Planning for PACS at Osaka University Hospital.

We have a plan to adopt PACS as a medical image information system in the new hospital. In order to construct PACS suitable for our hospital, a preliminary survey was carried out to determine how PACS should be introduced and what are the physicians requirements for a new medical image system. The most important requirement of the physicians was a good quality workstation. Our plan of a new medical image information system is as follows. A primary database will be constructed according to each of modalities in the Department of Radiology. In the Department of Medical Information Science, we will make a secondary database according to the patient. Although it may be difficult for us to obtain a sufficient budget digitalizing all medical images by our move to the new hospital, our goal is to establish total PACS throughout the new hospital in 1995.     

Activity of oxygen in liquid In-Sb alloys

In order to provide fundamental insights into the role of the ratio of the solvent metallic valences (V _b/V_a) on the compositional dependence of In γo, the activity coefficients of oxygen, γo, in liquid In-Sb alloys at 1073 K have been measured by modified coulometric titrations on the galvanic cell:O in liquid In-Sb alloys/ZrO₂( + CaO)/Air, Pt. Present results indicated the Henrian behavior of oxygen in liquid In-Sb alloys. The dependence of the activity coefficient of oxygen on alloy composition is represented as follows: N_IN 0 0.07 0.15 0.30 0.45 0.60 0.80 0.90 1 −lnγo 8.24 8.96 9.64 10.80 11.71 12.59 13.35 13.57 13.64 These results differ significantly from those predicted by Jacob and Alcock's equation and by Wagner's equation combined with Chang et al's correlation of the energy parameter, h. However, by modifying Chang et al's definition of ( V_b/ V_a), the Wagner's equation has been found to be capable of approximately describing the compositional dependence of the activity coefficient of oxygen in liquid In-Sb alloys.     

Evaluation of tricuspid regurgitation by the ultrasonic pulsed Doppler technique from a transcutaneous approach (author's transl)

Severity of tricuspid regurgitation was assessed by using a combined system of the ultrasonic pulsed Doppler technique and two-dimensional echocardiography from a transcutaneous approach. The study group comprised 47 patients with various heart diseases, who were clinically presumed to have tricuspid regurgitation, and 10 healthy subjects. 1) Pansystolic abnormal flow signal was detected in an area from the tricuspid valve into the right atrial cavity in 43 patients including 8 patients without definitive signs of tricuspid regurgitation. Such abnormal flow had never been detected in healthy subjects and was considered to represent tricuspid regurgitant flow. Tricuspid regurgitant flow usually exhibited a wide band spectrum of velocity component indicating a disturbed flow. In 4 patients with clinical signs of severe tricuspid regurgitation, a laminar flow was detected in the right atrial cavity, which was considered to indicate a regurgitant jet in the central part of tricuspid regurgitant flow. 2) The area where tricuspid regurgitant flow was detected was interpreted as revealing the main direction and spread of tricuspid regurgitant flow. Based on this finding, severity of TR was classified into 4 grades by the assessment on the basis of the distance reached by tricuspid regurgitant flow in the right atrium. Severity of tricuspid regurgitation was also classified into 4 grades by right ventriculography. The grade of tricuspid regurgitation assessed by Doppler technique was nearly consistent with that assessed by right ventriculography. Severity of tricuspid regurgitation was also classified into 4 grades on the basis of the extent of the area where the regurgitant flow spread, and nearly the same results were obtained as those described above. 3) Thus, the combined use of Doppler flowmetry and two-dimensional echocardiography proved to be useful for detecting tricuspid regurgitant flow and assessing the severity of tricuspid regurgitation.     

Successful surgical treatment for type B aortic dissection with Marfan's syndrome after aortic root and mitral valve replacement: report of a case

A 30-year-old female with Marfan's syndrome underwent aortic root replacement for annuloaortic ectasia and mitral valve replacement for mitral regurgitation. She remained well until 16 months postoperatively when she had sudden onset of pain. Preoperative angiogram showed Stanford B aortic dissection. Thoracoabdominal aortic replacement was performed successfully under deep hypothermic bypass.     

Efficient global optimization applied to wind tunnel evaluation-based optimization for improvement of flow control by plasma actuators

A kriging-based genetic algorithm called efficient global optimization (EGO) was employed to optimize the parameters for the operating conditions of plasma actuators. The aerodynamic performance was evaluated by wind tunnel testing to overcome the disadvantages of time-consuming numerical simulations. The proposed system was used on two design problems to design the power supply for a plasma actuator. The first case was the drag minimization problem around a semicircular cylinder. In this case, the inhibitory effect of flow separation was also observed. The second case was the lift maximization problem around a circular cylinder. This case was similar to the aerofoil design, because the circular cylinder has potential to work as an aerofoil owing to the control of the flow circulation by the plasma actuators with four design parameters. In this case, applicability to the multi-variant design problem was also investigated. Based on these results, optimum designs and global design information were obtained while drastically reducing the number of experiments required compared to a full factorial experiment.     

Photoluminescence properties of a hollandite compound K2Ga2Sn6O16

A hollandite compound K₂Ga₂Sn₆O₁₆ (KGSO) has photocatalytic activity, although little is known about the optical properties of the compound. To design a higher quality photocatalyst, studies on its optical properties are required. In this study, a KGSO powder and a SnO₂ (rutile structure) powder were prepared by the sol—gel method. Photoluminescence (PL) and PL excitation spectra of the two powders were measured. To our knowledge, this is the first report of PL from a hollandite compound. It was found that the band gap energy of the KGSO powder is 3.6 eV, the value of which is identical with that of the band gap energy of SnO₂. This was confirmed by the result of the photoacoustic spectrum of the KGSO. The shapes of the PL excitation spectra of the two powders agreed. Moreover, the PL spectra of the two powders have one broad band around 600 nm. From these results, one can conclude that the mechanism of PL of KGSO is the same as that of SnO₂. In air with ethanol, however, the time-course of the KGSO powder was different from that of the SnO₂ powder. By adding ethanol vapor in air, the PL intensity of the SnO₂ powder increased, whereas the PL intensity of the KGSO powder remained unchanged. By comparing the PL time-courses of the two powders with those of a commercial rutile TiO₂ powder, it was concluded that the photodesorption of O₂ in air with ethanol occurs on the SnO₂ powder, not on the KGSO powder. This was supported by the results of the inorganic carbon concentrations on the two powders. These results indicate that the behavior of O₂ on the KGSO surface during a photocatalytic oxidation is different from that on the SnO₂ surface during the oxidation.

© 2003 Elsevier Ltd. All rights reserved.     

Fault-tolerant automobile steering based on diversity of steer-by-wire, braking and acceleration

Steer-by-wire (SBW) systems, which have no mechanical linkage between the steering wheel and front wheels, are expected to improve vehicle safety through better steering capability. SBW system failures, however, can cause hazardous driving situations. This paper introduces fault-tolerant architecture based on diversified steering mechanisms consisting of SBW backed up with steering by braking and acceleration during SBW failures. These backup steering functions are chosen according to driver's intention of deceleration and acceleration. A loss of SBW function during front-obstacle avoidance on a straight highway is investigated by driving simulator experiments. The results show that the driver can maneuver the vehicle by the steering wheel during the SBW failures. Both cost and volume increase by excessive redundancy within SBW is avoided by the diversified design, thus facilitating SBW application on new-generation vehicles.     

Treatment of aquarium water by denitrifying photosynthetic bacteria using immobilized polyvinyl alcohol beads

During the purification of an aquarium for carp breeding, a relatively high level of chemical oxygen demand (COD) was removed by filtration systems packed with both alginate- and polyvinyl alcohol (PVA)-immobilized gel beads of Rhodobacter sphaeroides S. Low nitrate accumulation was observed in the alginate gel beads packed system due to denitrification, but high levels of nitrate and nitrite accumulation were observed in the PVA gel beads packed system. This phenomenon was caused by the inhibitory effect of PVA on nitrite reductase. The boric acid used for hardening gel beads of PVA slightly inhibited nitrate reductase. On the other hand, during the denitrifying growth experiments for this strain, boric acid inhibited cell growth, but PVA only partially inhibited cell growth. Based on electron equivalent (Y(eq.)), growth yields using various kinds of concentrations of PVA were almost identical. It was suggested that PVA might only limit the growth rate of this strain by the inhibition of nitrite reductase.