Dainichiseika (Japan)

Sheltering is one of the countermeasures used to mitigate radiation exposure during nuclear power plant accidents. The effectiveness of sheltering for inhalation exposure is often expressed by the reduction factor, which is defined as the ratio of the indoor to the outdoor cumulative radioactivity concentrations or doses. The indoor concentration is mainly controlled by the air exchange rate, penetration factor, and indoor deposition rate. Meanwhile, the air exchange rate depends on surrounding environmental conditions: the wind speed, leakage area normalised by the floor area of the house, and gross building coverage ratio. In this study, the ranges of the uncertainty of the reduction factors for particles and iodine in reactive gas form were investigated under various environmental conditions, and sensitivity analyses were conducted to understand the parameter with the most influence on the uncertainty of the reduction factor. From the results of the uncertainty analyses, the calculated reduction factor was highly variable depending on the environmental condition and the airtightness of the houses. The median and 95th percentile of the reduction factors for the older houses were 0.5 and 0.9 for particles and 0.07 and 0.4 for iodine in reactive gas form, respectively and these ranges were smaller for newer houses. From the results of the sensitivity analyses, the wind speed was the most influential parameter determining the reduction factor. Additionally, the wind speed was less influential for the reduction factor in newer houses.

In aquaculture, periodic measurement of fish body size is required to suitably assess growth progress. The aim of this study is to monitor the growth of free-swimming red sea bream, Pagrus major, farmed in net cages using multi-stereo-image measurement to determine the efficacy and potential applications of the method. After estimating appropriate sample sizes based on mean fork length and varying acceptable error ranges, we tracked fish growth using both multi-stereo-image measurement and traditional scoop-net capture methods for 1 year. Measurements were conducted four times every 3 months. In fish with fork length exceeding 40 cm, the appropriate sample sizes with acceptable error ranges of 1%, 2%, 3%, 4%, and 5% were around 100, 26, 12, 7, and 5 individuals, respectively, based on a 95% confidence interval. The fish exhibited most of their growth from June to December, with slower growth from February to June. This study provides evidence that multi-stereo-image measurement is an accurate and useful tool to enhance understanding of growth processes in cultured fish.

Degradation rate of hyaluronic acid to prolong its stability in vivo would be beneficial. We investigated a potential solution for prolonging the stability of hyaluronic acid within the body. We focused on decreasing the swelling ratio to slow the degradation rate of hyaluronic acid by insolubilizing sodium hyaluronate without using potentially harmful substances such as crosslinkers or modifiers. Hyaluronic acid formulations were created with three different swelling ratios and time-dependent morphological changes in hyaluronic acid formulations and were scored based on each swelling ratio. In vivo degradation was modeled in simulated body fluid and the extent of decay of test membranes were monitored over time. Results showed that, by adjusting the swelling ratio, the degradation rate of hyaluronic acid formulation could be controlled. Our research could lead to improvements in many products, not only preventive materials for postoperative adhesions, but also pharmaceutical products such as osteoarthritis treatments and cosmetic medicines.

A very short channel length was achieved in vertical-type metal-base organic transistors using a double-layered collector composed of N,N′-dimethyl-3,4,9,10-perylene tetracarboxylic diimide (Me-PTC) and N,N′-distearyl-3,4,9,10-perylene tetracarboxylic diimide (St-PTC). St-PTC showed low electric conductivities, but inserting it at the interface with the collector electrode improved the on/off ratio to 4 × 104 for a total collector thickness of 105 nm. The decrease in the off current was attributed to the low electric conductivity of St-PTC, and the increase in the on current was discussed from the viewpoint of the morphological change of the collector layer.

We employed a laser terahertz (THz) emission microscope (LTEM) as a novel tool for evaluating solar cells. LTEM images are obtained by exciting a polycrystalline silicon solar cell with femtosecond laser illumination and visualizing the local distribution of the optical response. THz emission signals also provide various types of information, such as the screening effect of the built-in electrical field near pn junctions. These results indicate that this technique can be used to evaluate the local photoelectric conversion efficiency distribution and dynamic behavior of optically excited carriers in solar cells.

A recently developed optical-write tool, incorporating a high-output laser with integrated grating light valve (i-GLV), has successfully been used to directly image high-resolution patterns useful for three-dimensional packaging schemes. This technology thus eliminates the need for masks for pattern creation. Automatic correction for any warpage from ultra-thin wafers is performed using a proprietary imaging technology. Different levels of dose intensity can be imaged on the resist in one exposure.

The antioxidant properties of different low molecular weight (LMW) chitosans (CS1; 22 kDa, CS2; 38 kDa, CS3; 52 kDa, CS4; 81 kDa) were examined for possible use in extended-release tablets. The criteria used were the ability of the chitosans to reduce Cu2+, and hydroxyl and superoxide radicals and N-centered radicals derived from 1,1'-diphenyl-2-picrylhydrazyl, via the use of ESR spectrometry. CS2 showed the highest scavenging activity. CS1 and CS3, however, were much less effective and CS4 was not a viable antioxidant. The results suggest that CS2 could be useful in combating the development of oxidative stress. A series of chitosan tablets were prepared using a spray drying method and evaluated as an extended-release matrix tablet using theophylline (TPH) as a model drug. The release of TPH from the different MW chitosan tablets increased with increasing MW of the chitosan used. CS2, CS3 and CS4 showed a reasonable release activity, but CS1 showed the shortest release activity. Moreover, the CS2-TPH tablet showed the highest scavenging activity of the three chitosan tablets (CS2-CS4) using 2,2’-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radicals. These results suggest that a CS2-TPH tablet could be potentially useful in an extended-release matrix tablet with a high antioxidant activity.

This paper presents the design and characteristics of a five-fingered haptic interface robot: HIRO III. The aim of the paper is to provide a high-precision force representation at the five human fingertips. HIRO III consists of a 15-degree-of-freedom (DOF) haptic hand, a 6 DOF interface arm and a control system. The haptic interface, which consists of a robot arm and hand, can be used in a large workspace and can provide multipoint contact between the user and a virtual environment. However, the following problems peculiar to a multi-DOF robot have resulted: a backlash, a large amount of friction, many motors, and many sensors. In order to solve these problems, a new mechanism and a wire-saving control system have been designed and developed. Furthermore, experiments in both free space and constraint space have been carried out. In comparison with the previous HIRO, the force errors in free space and in constraint space have been reduced to 30% and 57%, respectively. These results show a high-precision force representation and the great potential of HIRO III.