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Retrospective studies of treatment of tympanostomy tube insertion in infantile otitis prone patients caused by Penicillin-resistant Streptococcus pneumoniae were performed. Insertion of the Koken B type tympanostomy tube was performed with local anesthesia. The results were as follows: 1. In 25 otitis prone children, 19 (76.0%) were not recognized as having otitis media and otorrhea, but 6 (24.0%) were recognized. 2. Of the 25 children, 20 had the tympanostomy tube removed. Eighteen were not recognized as having otitis media and otorrhea during tympanostomy tube insertion, but 2 were recognized. 3. In 18 children, 2 developed otitis media after tympanostomy tube removal, but the other 16 children did not. 4. In 2 children who were recognized as having otitis media and otorrhea during tympanostomy tube insertion, 1 child actually had otitis media, whereas the other did not. 5. From this study, tympanostomy tube insertion is a useful method for treating the otitis prone children caused by Penicillin-resistant Streptococcus pneumoniae.

Although the straightness of hand paths is a widely accepted feature of human multijoint reaching movement, detailed examinations have revealed slight curvatures in some regions of the workspace. This observation raises the question of whether planned trajectories are straight or curved. If they are straight, 3 possible factors can explain the observed curvatures: (a) imperfect control, (b) visual distortion, or (c) interaction between straight virtual trajectories and the dynamics of the arm. Participants instructed to generate straight movement paths produced movements much straighter than those generated spontaneously. Participants generated spontaneously curved trajectories in the frontoparallel plane, where visual distortion is not expected. Electromyograms suggested that participants generated straighter paths without an increase in arm stiffness. These findings argue against the 3 factors. It follows that planned trajectories are likely to be curved.

An experimental study of tracheal reconstruction after lower tracheal resection using the inverted bronchus was performed in 8 dogs. After right upper lobectomy, the five cartilage rings of the lower trachea, ending three cartilage rings above the carina, was circumferentially resected; the right bronchus was transected just above the right second carina, the portion of the transected trachea above the carina was closed, and the right bronchus was inverted. The peripheral end of the upper trachea was anastomosed to the inverted right bronchus, and the intermediate bronchus was anastomosed to the lateral wall of the left bronchus. After completion of the airway reconstruction, the anastomotic site was wrapped with an omental flap. Although anastomotic complication were observed in two dogs, all the dogs survived the operation. Bronchoscopically and histopathologically, the findings for the inverted bronchus were almost normal three to four weeks after the operation. The clinical relevance of such a tracheal reconstruction is discussed.

The performance of two Nb3Sn conductors for the ITER central solenoids was tested. The current sharing temperatures (T-cs) were measured over 17 050 electromagnetic cycles, including four thermal cycles between 4.2 K and room temperature. T-cs declined almost linearly over the 10 000 rated electromagnetic cycles. T-cs was nearly constant for 70% of the rated electromagnetic cycles, which implies the existence of a fatigue limit in the conductors. For 85% of the rated cycles, a very sharp T-cs degradation of approximately 0.2 K occurred. Some type of large deformation of strands, such as buckling, may have caused this sharp degradation. The effective strain degraded linearly with the electromagnetic force on the cable. The gradient after 10 000 cycles was 1.5 times greater than that before cycling. After 10 000 cycles, the ac losses of both conductors considerably decreased to less than half of those before cycling. These ac losses before cycling were less than a fourth of those of toroidal field conductors. After the test campaign, destructive inspection of the conductor clarified that on average, the distribution of residual strain along the cable was almost uniform at -32 ppm. It was also clarified that some strands were visibly deformed under a high magnetic field, whereas strands under a low magnetic field did not appear to be deformed. The deformations of the central solenoid cable were larger and wavier in subcables than those observed in the toroidal field cable. This plastic deformation of the strands could be one of the major reasons for the T-cs degradation during cyclic operation.

The performances of six Nb3Sn conductors for the ITER Toroidal Field coils were tested. Four of them showed similar degradation rates of their current sharing temperatures T-cs over 1,000 electromagnetic cycles. By contrast, two of them showed sharp T-cs degradations at 50 cycles, after which their slopes became similar to those of the other four conductors. These two cables seemed to shrink under high magnetic fields during the first 50 cycles, which caused the sharp T-cs degradation. This shrinkage might arise from a decline in cable rigidity due to, for example, the deformation of strands or the breakage of the Nb3Sn filaments. The four mass-produced conductors had roughly the same AC loss before cycling. After 1,000 cycles, the AC losses of all the conductors decreased markedly to less than half of those before cycling, and the values became approximately the same. After the test campaign, the destructive inspection of two of the conductors made it clear that the conductor had shrunk by about 520 ppm under the high magnetic field during the test. It was also clarified that some strands were visibly deformed under the high magnetic field, whereas those under the low magnetic field did not look distorted. This plastic deformation of the strands could be one of the major reasons for the T-cs degradation with cyclic operation.

A 13 T-46 kA Nb3Al conductor with steel jacket has been developed in the framework of ITER-EDA. The thermal strain will appear on the Nb3Al strands after heat treatment, when the steel jacket is used because of difference in their thermal expansion. The conductor critical current performance is degraded by this process. The critical current performance of this conductor was then studied to verify no degradation during the fabrication and small deterioration in the critical current performance even when the steel jacket is used. The thermal strain is evaluated to be < 0.4% for the developed Nb3Al conductor. The critical current deterioration for this case is < 10%. Also, the critical current of the conductor without the thermal strain shows good agreement with that calculated by the critical current of a strand multiplied by its number, 1152. Consequently, no degradation during the conductor fabrication process can be verified. Moreover, the critical current is expected to be more than 90 kA for the thermal strain of 0.4%, resulting in a large margin against the nominal current, 46 kA. 2001 Elsevier Science B.V. All rights reserved.

The performance of tour Nb3Sn conductors for the ITER central solenoids was tested. The current sharing temperatures (T-cs) were measured over approximately 9000 electromagnetic cycles, including two or three thermal cycles between 4.2 K and room temperature. T-cs, increased and became almost constant through the cycling. The gradient of the electric field against the temperature gradually decreased against cycling. The degradations caused by the electromagnetic force of the short twist pitch conductors were smaller than that of the original twist pitch conductor. The ac losses of short twist pitch conductors were several times higher than that of original twist pitch conductor. The dents and the removals of the Cr plating on the strands, which were formed during cabling, decreased the electric resistance between strands, which may cause the observed high ac loss. Inspection of the cable showed neither a clear bias of cable in the cross-sectional surface nor distorted strands in the lateral face. The high rigidity of the short twist pitch cable could prevent these plastic deformations, caused by the Lorentz force.

The optimization of the heat treatment of Nb3Sn conductors for toroidal field coils in ITER was attempted to improve the current sharing temperatures (T-CS). Using the strand, we chose the pattern at 570 degrees C for 250 h and 650 degrees C for 100 h as the best, which increased the critical current and maintained the residual resistivity ratio higher than 100. The behavior of the critical current of the strand vs. the magnetic field, temperature, and strain was also improved. This pattern was used on two conductors, and their performances were tested. T-CS was evaluated over 1000 electromagnetic cycles and one thermal cycle. A sharp T-CS occurred at 50 cycles. Then T-CS linearly. Although this tendency was similar to the conductors that were heat treated with the original pattern, the degradation rates were improved. The ac losses (Q) before cycling were approximately 10% lower than those of the original pattern. Q after cycling became almost equivalent between two patterns. The conductor was inspected after the test, which showed that the conductor under the high-magnetic-field zone had contracted by approximately 600 ppm during the test. Some clearly deformed strands were observed under the high-magnetic-field zone, which could degrade T-CS.