Function after intersphincteric resection for low rectal cancer and its influence on quality of life.

AIM: The aim of the study was to investigate function and quality of life after different types of intersphincteric resection (ISR). METHOD: Between January 2006 and February 2008, 45 patients (34 men and 11 women) with distal third rectal cancer underwent curative ISR. Function was evaluated using the Memorial Sloan Kettering Cancer Center bowel function questionnaire and Wexner score, anal manometry and measurements of rectal capacity were also performed. Quality of life was assessed using the Serbian version of the European Organisation for Research and Treatment of Cancer, quality of life questionnaire (EORTC QLQ-C30) and the translated version of the fecal incontinence quality of life scale (FIQL). RESULTS: There were no postoperative deaths. Partial ISR was performed in 22 (48.9%) patients, subtotal ISR was performed in 19 (42.2%) patients and total ISR was performed in four (8.9%) patients. Anastomotic leakage occurred in nine (20%) patients. Five (11.1%) of 45 patients had major (complete) incontinence and a further six (13.3%) patients had continuing frequent faecal leakage 12 months after ileostomy reversal. There was no significant difference in quality of life between the groups in the EORTC QLQ-C30 scale, but this was significantly altered by internal anal sphincter resection in two of the FIQL scales (coping/behaviour and depression/self-perception). CONCLUSION: Although ISR does not affect quality of life in general, the extent of internal anal sphincter resection has a negative impact on symptom-specific quality of life owing to faecal incontinence.

Birefringence measurement in double-clad fiber lasers with large cross section.

We report on birefringence measurements in double-clad fibers with large cross section, doped with neodymium and ytterbium. The experimental results for rectangular double-clad fibers are compared with those for single-clad circular neodymium-doped fibers, taking into account existing models of stress- and geometry-induced birefringence. We demonstrated that the ellipticity of an outer silica cladding has no effect on birefringence in large-area double-clad fibers. The stress-induced birefringence is shown to depend on the ratio between the diameter of an internal silica support and the linear dimensions of the rectangular outer cladding. The stress-distribution pattern is derived to prove the experimental results.

High-power 390-nm laser source based on efficient frequency doubling of a tapered diode laser in an external resonant cavity.

We frequency doubled the single-frequency beam from an external-cavity tapered laser diode operating at 780 nm in a resonant cavity containing a beta -barium borate crystal to generate an output at 390 nm with high efficiency. Output powers as great as 233 mW were obtained, corresponding to an efficiency of 65%/W . The resonant-cavity design was a low-loss three-mirror configuration that provided compensation for astigmatism and coma. The laser diode frequency was locked to the doubling-cavity resonance by use of the Hänsch-Couillaud discrimination technique.

Nonlinear-optical modulator for high-power fiber lasers.

We propose a novel nonlinear-optical fiber modulator for high-power (>1-W) single-mode fiber lasers. The device is based on transferring the amplitude modulation from a low-power signal at the Stokes frequency onto a high-power beam through stimulated Raman scattering. The efficiency and limitations of the Raman modulator when highly Ge-doped fiber is used is considered. An insertion loss of less than 0.4 dB and an extinction ratio of 20 dB are predicted for modulation of a 10-W single-mode Nd-doped fiber laser.

Effects of previous muscle contractions on cyclic movement dynamics.

In addition to muscle elastic energy, enhancement of movement performance in a stretch-shortening cycle could also be due to an increase in initial muscle force during the stretching phase. This hypothesis was tested by examining 9 male physical education students during maximum voluntary knee extensions performed with and without previous knee flexion. In both conditions movements were performed with various external loads. In addition, the force-velocity curve (FVC) parameters of the knee extensor muscles were also determined. As simple model of a muscle impulse was constructed in order to select independent biomechanical variables relevant to movement dynamics. The experimental results demonstrated that previous knee flexion enhanced the maximum angular velocity of knee extension. This effect decreased with increasing movement duration (i.e. increased external load), as well as giving positive correlation coefficients between the magnitude of this effect and the rate of development of knee extensor tension. These results are discussed in relation to a model of the dynamics. It is shown that previous muscle contractions performed during braking in the negative movement phase might play an important role in enhancing performance in cyclic movements. This role would be especially important in transient contractions of primarily slow twitch fiber muscles.