Examination of the long-term stability of radiation survey meters and electronic pocket dosemeters

To describe the stability of radiation survey meters (RSMs) and electronic pocket dosemeters (EPDs), we examined 28 EPDs and 24 RSMs: 12 used NaI(Tl) scintillation RSMs and 12 used Geiger-Muller(GM) RSMs. We used simple methods for the relative calibration of the 24 RSMs and 28 EPDs. The RSM and EPD measurements were compared with a calibrated RSM and EPD (reference: traceable from the national standard of exposure) using a homemade measurement device to maintain the reproducibility of the measurements with reference radiation sources (i.e. 137Cs, 90Sr and 67Ga). The response of RSMs and EPDs, especially after prolonged use, should be checked periodically. In particular, GMRSMs that have been in use for many years have very low sensitivity and poor reproducibility. Our simple method for the relative calibration of RSMs and EPDs was shown to be effective for quality assurance purposes in checking RSMs and EPDs. We recommend regular checks and calibration for sustained performance of RSMs and EPDs.     

Techniques for imaging human metaphase chromosomes in liquid conditions by atomic force microscopy

The purpose of this study was to obtain three-dimensional images of wet chromosomes by atomic force microscopy (AFM) in liquid conditions. Human metaphase chromosomes-obtained either by chromosome spreads or by an isolation technique-were observed in a dynamic mode by AFM in a buffer solution. Under suitable operating conditions with a soft triangular cantilever (with the spring constant of 0.08-0.4?N?m(-1)), clear images of fixed chromosomes in the chromosome spread were obtained by AFM. For imaging isolated chromosomes with the height of more than 400?nm, a cantilever with a high aspect ratio probing tip was required. The combination of a Q-control system and the sampling intelligent scan (SIS) system in dynamic force mode AFM was useful for obtaining high-quality images of the isolated chromosomes, in which globular or cord-like structures about 50?nm thick were clearly observed on the surface of each chromatid.     

Fish test for endocrine-disruption and estimation of water quality of Japanese rivers

The LC50 values (72 h) of 17beta-estradiol (E2), p-nonylphenol (NP) and bis-phenol-A (BPA) to adult male and female medaka were 3.5 and 3.5, 0.85 and 0.87, and 6.8 and 8.3 mg L(-1), respectively; the LC50 values to embryos were 0.46, 0.13 and 5.1 mg L(-1), respectively. The IC50 values for inhibition to egg hatching were 0.47, 0.85 and 9.0 mg L(-1), respectively. These values were much higher than concentrations detected in river water in Japan and the chemicals were considered to have no lethal effect on the fish in an aquatic environment. Mature male medaka was continuously exposed to 0.005, 0.05 or 1.0 microg L(-1) of E2, or to 0.1, 10 or 100 microg L(-1) of NP or BPA. Female specific proteins (FSP) were induced in the blood of male medaka that were exposed for 5 weeks to E2 higher than 0.005 microg L(-1), NP higher than 0.1 microg L(-1), or BPA higher than 10 microg L(-1). Based on these FSP inducible concentrations and reported concentrations of E2, NP and BPA in Japanese river water, some river water contaminated by E2 or NP could be estimated as the FSP inducible in male medaka.     

Intraoperative monitoring of depth-dependent hemoglobin concentration changes during carotid endarterectomy by time-resolved spectroscopy

By measuring the adult human head during carotid endarterectomy, we investigate the depth sensitivity of two methods for deriving the absorption coefficient changes (Dmu(a)) from time-resolved reflectance data to absorption changes in inhomogeneous media: (1) the curve-fitting method based on the diffusion equation (DE-fit method) and (2) the time-independent calculation based on the modified Lambert-Beer law (MLB method). Remarkable differences in the determined values of Dmu(a) caused by clamping the external carotid artery and subsequently clamping the common carotid artery were observed between the methods. The DE-fit method was more sensitive to mu(a) changes in cerebral tissues, whereas the MLB method was rather sensitive to mu(a) changes in the extracerebral tissues. Our results indicated that the DE-fit was useful for monitoring the cerebral blood circulation and oxygenation during neurosurgical operations. In addition, the combined evaluation of mu(a) changes with the DE-fit and MLB methods will provide us with more available information about the hemodynamic changes in the depth direction.     

Mating Disruption of a Carpenter Moth, <Emphasis Type="Italic">Cossus insularis</Emphasis> (Lepidoptera: Cossidae) in Apple Orchards with Synthetic Sex Pheromone,and Registration of the Pheromone as an Agrochemical

Mating disruption of the carpenter moth, Cossus insularis (Staudinger) (Lepidoptera: Cossidae), with a synthetic version of its sex pheromone, a mixture of (E)-3-tetradecenyl acetate and (Z)-3-tetradecenyl acetate, was tested for three successive years in apple (Malus domestica Borkh.) orchards. Pheromone trap catches, percentage mating of tethered females and females enclosed with males in a mating cage, and tree damage were measured in both the pheromone-treated and untreated control orchards. The attraction of male moths to pheromone traps at heights of 1.5, 3, and 5 m was strongly disrupted when the pheromone dispensers were placed at 1.5 m height. Mating of tethered females placed at 1 m was completely inhibited, and the mating of tethered females at a height of 3 m was significantly reduced by the treatment in comparison to matings in an untreated control orchard. Similarly, mating of pairs of moths enclosed in mating cages was significantly reduced by the synthetic pheromone treatment in comparison to controls. The percentage of damaged trees in the pheromone-treated orchard also decreased significantly over the course of the experiment. These results suggest that mating disruption with the synthetic sex pheromone appears promising for reducing damage caused by C. insularis in apple orchards in Japan, and a commercial mating disruption product has been developed and registered.     

Elucidation of Softening Mechanism in Rinse-Cycle Fabric Softeners. Part 2: Uneven Adsorption—The Key Phenomenon to the Effect of Fabric Softeners

We investigated the actual factor determining the softening effect of a fabric softener. The adsorption area of the softener on model cotton cloths and yarns was identified using bromophenol blue. There was almost no softener at the cross-points of the yarns in the cloth samples or in the inner part of the yarns. The softening performance was better when there was less softener at the cross-points of the yarns than when the yarns were evenly covered by the softener. Thus we conclude that the presence of softener at the cross-points of yarns is not a vital factor in the softening effect. In addition, more softener was found on the outer part of the yarn than the inner part, indicating gradation in the adsorption pattern of the softener. Thus, we propose that more softener is adsorbed on the exposed part of the yarn in a cloth, and the formation of a hydrogen-bonding network containing bound water is inhibited, thus softening the outer part of the yarn. However, the presence of a small amount of softener in the inner part of the yarn preserves the hydrogen-bonding network. Favorable elasticity, or bounce, of the yarns and cloth is realized when an appropriate amount of softener is used. Excess softener would reach the inner part of the yarn, reducing the diameter of the core part of the yarn, making the cloth appear wilted.     

Evaluation of the implant type tissue-engineered cartilage by scanning acoustic microscopy

The tissue-engineered cartilages after implantation were nonuniform tissues which were mingling with biodegradable polymers, regeneration cartilage and others. It is a hard task to evaluate the biodegradation of polymers or the maturation of regenerated tissues in the transplants by the conventional examination. Otherwise, scanning acoustic microscopy (SAM) system specially developed to measure the tissue acoustic properties at a microscopic level. In this study, we examined acoustic properties of the tissue-engineered cartilage using SAM, and discuss the usefulness of this devise in the field of tissue engineering. We administered chondrocytes/atelocollagen mixture into the scaffolds of various polymers, and transplanted the constructs in the subcutaneous areas of nude mice for 2 months. We harvested them and examined the sound speed and the attenuation in the section of each construct by the SAM. As the results, images mapping the sound speed exhibited homogenous patterns mainly colored in blue, in all the tissue-engineered cartilage constructs. Contrarily, the images of the attenuation by SAM showed the variation of color ranged between blue and red. The low attenuation area colored in red, which meant hard materials, were corresponding to the polymer remnant in the toluidine blue images. The localizations of blue were almost similar with the metachromatic areas in the histology. In conclusion, the SAM is regarded as a useful tool to provide the information on acoustic properties and their localizations in the transplants that consist of heterogeneous tissues with various components.     

Assembly study for JT-60SA tokamak

The assembly scenarios and assembly tools of the major tokamak components for JT-60SA are studied in the following. (1) The assembly frame (with a dedicated 30-tonne crane), which is located around the JT-60SA tokamak, is adopted for effective assembly works in the torus hall and the temporary support of the components during assembly. (2) Metrology for precise positioning of the components is also studied by defining the metrology points on the components. (3) The sector segmentation for weld joints and positioning of the vacuum vessel (VV), the assembly scenario and tools for VV thermal shield (TS), the connection of the outer intercoil structure (OIS) and the installation of the final toroidal field coil (TFC) are studied, as typical examples of the assembly scenarios and tools for JT-60SA.     

Rising Tc in Bi and Cu co-doped BaTiO3

The solid solution (Ba_1−2xBi_2x)(Cu_xTi_1− x)O₃ (0.0 < x ≤ 0.10) was prepared by conventional high temperature reaction. In the region of x ≤ 0.040 single phases of tetragonal perovskite-type compounds were obtained and the c-axis increased up to x = 0.015 and the maximum of the a/c ratio was 1.0123 at x = 0.010. In x > 0.040 a small amount of an unknown impurity phase appeared in addition to a tetragonal perovskite-type phase. The Curie temperature Tc increased to 140 °C at x = 0.010. Rising Tc was confirmed by temperature dependence of the dielectric constants and the endothermic peaks observed in DTA curves. This is the first example for rising Tc in the solid solution based on BaTiO₃ except for doping of Pb²⁺ ion.     

A novel six-phase inverter system with 60-step output voltages forhigh-power motor drives

A novel six-phase voltage-fed inverter system is proposed. The system consists of two main three-phase inverters, coupling reactors, and an additional single-phase inverter. The ripple voltage injected into the DC link by the additional inverter results in 60-step load voltages with the help of the coupling reactors. The main inverters operate at the same frequency as the output, and the additional inverter operates at a frequency six times higher. The advantages and disadvantages of the system are quantitatively discussed