Synthesis of hydrogels with a gradient crosslinking structure by electron beam radiation to an aqueous solution of poly(sodium acrylate)

Hydrogels were prepared by electron beam (EB) radiation to the aqueous solutions of poly(sodium acrylate) in the presence of potassium and ammonium peroxodisulfates. The effects of EB radiation dose, as well as polymer, and initiator concentrations on the formation of gels, were investigated. On the basis of the storage modulus, loss modulus, and complex viscosity of the isolated gels determined by rheological measurement, the relationship between the radiation conditions and the rheological properties of the gels was discussed. Furthermore, hydrogels with a gradient crosslinking structure in a depth direction were synthesized by controlling EB radiation dose.     

Misfit Layer Compounds: A Platform for Heavily Doped 2D Transition Metal Dichalcogenides

Transition metal dichalcogenides (TMDs) display a rich variety of instabilities such as spin and charge orders, Ising superconductivity, and topological properties. Their physical properties can be controlled by doping in electric double-layer field-effect transistors (FET). However, for the case of single layer NbSe₂, FET doping is limited to ≈ 1 × 10¹⁴ cm⁻², while a somewhat larger charge injection can be obtained via deposition of K atoms. Here, by performing angle-resolved photoemission spectroscopy, scanning tunneling microscopy, quasiparticle interference measurements, and first-principles calculations it is shown that a misfit compound formed by sandwiching NbSe₂ and LaSe layers behaves as a NbSe₂ single layer with a rigid doping of 0.55–0.6 electrons per Nb atom or ≈ 6 × 10¹⁴ cm⁻². Due to this huge doping, the 3 × 3 charge density wave is replaced by a 2 × 2 order with very short coherence length. As a tremendous number of different misfit compounds can be obtained by sandwiching TMDs layers with rock salt or other layers, this work paves the way to the exploration of heavily doped 2D TMDs over an unprecedented wide range of doping.     

Development of a frameless and armless stereotactic neuronavigation system with ultrasonographic registration

OBJECTIVE: We have developed a frameless stereotactic neuronavigation system that allows navigation during neurosurgical procedures through an image formed from integrating ultrasonography and preoperative magnetic resonance (MR) imaging and/or x-ray computed tomography. METHODS: The system consists of a ultrasound imaging scanner, a workstation with an image capture board, and an ultrasonic tracking sensor with a 5-MHz ultrasonographic transducer. The ultrasonic tracking sensor measures the position and orientation of the ultrasonographic transducer. The oblique plane of the MR/computed tomographic image corresponding to the ultrasound image is then displayed on the workstation monitor. A three-dimensional computer graphic representation of the integrated image is also reported as a preliminary test. For the patient-image registration, the coordinates of digitized and imaged markers on a specifically developed reference frame are used. The reference frame is noninvasive because it is not bolted but only fastened to the patient's head with silicon. RESULTS: Based on the findings from the clinical application of the system in three cases, the system was advantageous because of the surgical procedures could be controlled by intraoperative ultrasonography as well as by preoperative MR/computed tomographic images. Missing parts in the ultrasonogram were supplemented with preoperative MR/computed tomographic images. At other times, spatial positioning and visualization by ultrasonography were useful for identifying anatomical objects in the image. CONCLUSION: This preliminary study of the frameless integration of ultrasonography into stereotactic space demonstrated its clinical usefulness. We believe that the concept of pre- and intraoperative image-guided surgery presented here will find increasing use in the future.     

Shock compaction of NiTi alloy powder

The shock recovery experiment for the equiatomic NiTi alloy powder was performed by the flyer impact technique. The powder samples with the initial density of 70% of full density were shock-treated in the dyer velocity range 0.65 to 1.7 km sec^?1. At the optimum flyer velocity of 1.3 km sec^?1, the powder sample is compacted up to 99.5% of the full density. With increasing flyer velocity, new pores are formed in the melted layer instead of the disappearance of initial interstices. Effects of the mechanical deformation and the annealing brought by the shock treatment evidently appear in the temperature dependence of electrical resistivity accompanied with the martensitic transformation. The shock state and the relaxation of the heterogeneous temperature by the shock treatment are estimated, which indicate the annealing condition caused by shock-loading and the formation of new pores.     

A case of polyangiitis overlap syndrome

PURPOSE: To examine the quality of life after repair of esophageal atresia, follow-up studies were performed in 58 of 71 surviving patients (81.7%). METHODS: Fifty patients with primary anastomosis and all eight surviving patients with colon interposition were seen. The mean age was 25.3 years (range, 20 to 31). Symptoms were evaluated by a standardized interview. Quality of life assessment was performed using a visual analogue scale (0 to 100 points), the Spitzer Index (5 dimensions, 10 points), and the Gastrointestinal Quality of Life Index (GIQLI, 5 dimensions, 128 points). RESULTS: After primary anastomosis the estimated meal capacity was unrestricted in 46 patients (92%), but numerous symptoms such as recidivating cough (60%), hold up (48%), and short breath (30%) were reported. All symptoms except cough were seen more frequently in patients with colon interposition, and all of these patients suffered from periods of short breath. Quality of life scores were higher in patients with primary anastomosis compared with colon interposition. The difference in the visual analogue scale score did not reach statistical significance, but the mean Spitzer Index was 9.7 compared with 8.8 after colon interposition (P < .05). The GIQLI after primary anastomosis was similar to that in healthy controls and was significantly lower in patients with colon interposition. This was because of specific symptoms, which scored 49.3 after colon interposition compared with 61.7 after primary anastomosis (P < .05) and to 54.8 (SD 5) in healthy controls (P < .05). Physical and social functions, emotions, and inconvenience of a medical treatment scored similar in patients with primary anastomosis, colon interposition, and healthy volunteers. CONCLUSIONS: The long-term quality of life after primary anastomosis was excellent. Patients with colon interposition suffer more frequently from various gastrointestinal and respiratory symptoms, but they lead an otherwise normal life.     

A comprehensive economic analysis of biomass gasification systems

This paper presents a comprehensive economic analysis of biomass gasification systems. There has recently been interest in promoting biomass energy systems in Japan's domestic sector. However, there are problems in achieving this project. The costs of plant construction are very high compared with conventional plants. Accordingly, the unit costs of electricity will be increased to levels comparable with those of other environmental energy systems. Copyright © 2004 Wiley Periodicals, Inc. In this paper, biomass energy systems using woody biomass are proposed from the viewpoint of successful environmental business. Biomass integrated gasification combined cycle (BIGCC) plants operated by independent power producers and biomass gasification cogeneration (BGCGS) plants in sawmills or asphalt‐concrete production factories have the potential for implementation in the near future. Our analysis concludes that the systems proposed in this paper provide the following outcomes with subsidies: (1) the generating cost of BIGCC ranges from 15.1 to 36.6 yen/kWh, (2) the generating cost of BGCGS ranges from 2.6 to 32.2 yen/kWh, and (3) the cost reduction of BGCGS products in asphalt factories amounts to about 60 million yen per year. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(3): 52–63, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20089     

Test run of combined propulsion,levitation and guidance system at Miyazaki test track

In commercializing the superconducting Maglev system it is important to reduce the cost, especially that of ground coils constructed along the whole length of the guideway. For this purpose we have examined the combined propulsion, levitation and guidance system (PLG system) which can generate levitation, guidance and propulsion forces by the same coil. This paper describes the test run of the PLG system, whose ground coils (PLG coil) are constructed in one part of the Miyazaki test track. In designing the PLG coil, we make clear the magnitudes of the force acting both under normal and unusual conditions because the electromagnetic force, which levitates, guides, and propels the vehicle, directly acts on the magnet winding of the PLG coil. In the experiment, we examine both the performance of the vehicle and the force of a PLG coil. The measurement of the force at the PLG coil gives not only propulsion force and levitation force directly, but also guidance stiffness by sifting the measured coil. Good correlation recognized between the calculation and the experiment in the propulsion force, levitation force, and guidance stiffness proves that the required characteristics can be expected from the PLG system even under combination of propulsion, levitation and guidance.