Writing and visualization of low-threshold type II Bragg gratings in stressed optical fibers

Type II phase gratings were produced by the use of holographic side writing in high-birefringence optical fibers with UV fluences of 0.06 J/cm(2) over 10 times lower than that previously reported for standard fibers. The grating growth, transmission and reflection spectra, temperature response, short-wavelength light ejection, and high-resolution confocal microscopy images are reported. Diffraction theory is used to interpret the grating microstructure revealed by confocal microscopy. Each period of the grating is shown to consist of a plate of oriented cracks, and arguments relating to the arrangement of the cracks and crack growth are linked to the observed grating-growth dynamics.

Spatial distribution of 650-nm luminescence in UV-processed germanosilicate preforms

Broadband luminescence at ~650 nm obtained on excitation at 633 and 647.5 nm is shown to be markedly increased in a UV-processed germanosilicate preform. The luminescence profile across the core is found to follow that of the germanium concentration.

Exsanguinating hemorrhage from urinary ileal conduit in patient with portal hypertension

A patient with an ileal conduit diversion after cystectomy for carcinoma of the bladder is seen with cirrhosis and portal hypertension. Massive bleeding from the peristomal varices developed. Our experiences with conservative treatment is outlined.

A rapid method for the estimation of estriol in plasma during pregnancy

A rapid, reliable fluorimetric method for the determination of estriol (E3) in plasma is described. The method is eminently suitable for use in hospital laboratories and provides results within 5 hours of the reception of samples. It has several features not found in other methods. As little as 0.2 ml of plasma is required, all additions and aliquoting procedures are semi-automated an no special technical skill is necessary. A technician can carry out 20 determinations per day. Average recoveries of 70% are routinely achieved, and the accuracy (2.4%) and the precision (4.0%) of the method are remarkably good for an assay of this type. A spectrofluorometer of high sensitivity, counting equipment and a high temperature oven are the essential major pieces of equipment.