8,122 research outputs found
AGING-INDUCED WAVELENGTH SHIFTS IN 1.5-MU-M DFB LASERS
No full textWe report measured wavelength shifts of over one hundred 1.5-mum DFB lasers aged under three different conditions for a period corresponding to the system's lifetime (approximately 25 years). The results show that the lasers aged at lower temperature (thus higher optical power) have wider spread of wavelength shifts than the lasers aged at higher temperature. No correlation was observed between the wavelength shifts and the aging rates or the aging-induced changes in the threshold currents. The aging-induced wavelength shifts were relatively small (+/-1 angstrom) for most lasers. However, about 10% of the lasers exhibit larger wavelength shifts of up to about +/-4 angstrom
Epidemiological features of supracondylar fractures of the humerus in Chinese children.
No full textWe studied 450 children with a supracondylar fracture of the humerus in the period 1991 to 1995, and were able to collect full management details in 403 of them (253 boys and 150 girls). The median age at presentation was 6 years (6.6 years in boys, and 5 years in girls), with the nondominant humerus 1.5 times more commonly injured. Fifteen percent of children presented more than 1 day after the injury. Garland type III fractures constituted 45% of cases, type I 30%, and type II 24%, with flexion type fractures present only in 1% of the children. A nerve injury was associated with the fracture in 19 cases. Although the radial pulse was not palpable at presentation in nine patients, only one child had diminished distal circulation requiring exploration. Concomitant fractures were present in 14 patients. Elbow hyperextension was greater than in a comparable group of noninjured children. Open reduction was necessary in 20% of these children, most being managed by manipulation under anaesthesia, at times associated with percutaneous Kirschner wiring. The hospital stay was 2 days or less in two-thirds of the patients, with more than 90% discharged home within 1 week of admission. In conclusion, many Chinese patients attend hospital later than their Western counterparts, and the rate of flexion-type injuries is low
Bone mineralization gradient at the callotasis site.
No full textThirteen patients (18 lengthenings; mean age at operation, 11.0 years) underwent dual-energy X-ray absorptiometry (DEXA) scanning weekly during the distraction phase, at 2-week intervals until removal of the fixator, and at the time of each outpatient visit after removal of the apparatus for a median of 353 days. The three transverse regions remained significantly different in the 7 achondroplastic patients throughout the study, but the difference among these regions became nonsignificant by fixator removal in the 11 limb length discrepancy (LLD) patients. The most proximal region was significantly more mineralized throughout the study in the achondroplastic patients. The central region became the region of highest mineralization in the LLD patients by week 16 after removal of the fixator. The three longitudinal regions showed significantly different mineralization at all time points except at fixator removal. The central and medial regions always showed the highest mineralization. The mechanical characteristics of the fixator and the biomechanical features of the lengthening site may account for the mineralization gradient reported in this study and should probably be taken into account when planning removal of the fixator and subsequent weight-bearing
[Evaluation of knee peak torque in athletic and sedentary children].
No full textOBJECTIVES:
We examined the influence of sex, level of activity, and pubertal status on knee extension (Ext) and flexion (Fl) peak torque (PT) in children using an allometric modeling approach.
METHODS:
A total of 140 students (67 males, 73 females) aged 12/13 years were enrolled from a Hong Kong junior high school, whose curricula were based on physical education (n=69) or arts (n=71). Isokinetic concentric Ext and Fl PT of the dominant leg was assessed at 1.04 rad/sec using a Cybex II+ dynamometer and body mass, stature, and pubertal stage were measured. A repeated-measures ANOVA test was performed on absolute PT data with muscle action (Ext and Fl) as a within-subject factor and between-subject factors including sex, group, and pubertal stage. To assess the effects on body size-adjusted PT, linear ANCOVA and log-linear ANCOVA techniques were used with body mass and stature taken as covariates.
RESULTS:
Peak torque was significantly greater in boys compared to girls, and in the physical education group compared to the arts group. When PT was adjusted for differences in body size, there was a greater difference in PT between girls in the two groups compared to boys, and there was a significant effect of pubertal stage. Allometric analysis showed that PT was influenced more by stature than body mass, and PT increased at a greater rate than body size (both p<0.01).
CONCLUSION:
There may be a need for a physical activity intervention in sedentary 12/13 year old girls. Peak torque appears to increase disproportionately to body size. This may result from a greater increase in leg muscle mass relative to body mass
Inclusion of biological factors in parallel architecture NTCP model for radiation-induced liver disease
No full textTransurethral resection of bladder tumors followed by radiotherapy with or without chemotherapy for bladder preservation in patients with invasive bladder transitional cell carcinoma: Preliminary NTUH experience
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