Endoscopic management of duodenal perforations caused by migrated biliary plastic stents.

Background and study aims Duodenal perforation by migration of plastic stents placed to treat biliary lesions is rare but can be life-threatening. Surgical management is preferred, but it may increase risks of mortality and morbidity, especially in patients with underlying comorbidities and those of advanced age. We describe five cases of duodenal perforation that were successfully managed endoscopically. Four patients were elderly, and one had end-stage renal disease. We used cylindrically adapted cap-fitted endoscopy to successfully retrieve migrated plastic stents and to close the perforated walls with hemoclips. No post-procedural complication was noted. In conclusion, endoscopic management is appropriate as a first-line approach in patients with duodenal perforations caused by plastic stent migration.

Mycobacterium intracellulare Pleurisy Identified on Liquid Cultures of the Pleural Fluid and Pleural Biopsy.

Pleural effusion is a rare complication in non-tuberculous mycobacterial infection. We report a case of Mycobacterium intracellulare pleuritis with idiopathic pulmonary fibrosis in a 69-year-old man presenting with dyspnea. Pleural effusion revealed lymphocyte dominant exudate. M. intracellulare was identified using a polymerase chain reaction-restriction fragment length polymorphism method and liquid cultures of pleural effusion and pleural biopsy. After combination therapy for M. intracellulare pulmonary disease, the patient was clinically well at a 1-month follow-up.

Color filter incorporating a subwavelength patterned grating in poly silicon.

A color filter based on a subwavelength patterned grating in poly silicon was proposed and realized on a quartz substrate. It was produced by utilizing the laser interference lithography technique to feature wide effective area compared to the costly e-beam lithography. An oxide layer was introduced on top of the silicon grating layer as a mask to facilitate the silicon-etching and to enhance the filtering selectivity as well. The structural parameters for the device include the grating pitch and height of 450 nm and 100 nm respectively, the silicon stripe width of 150 nm, and the oxide thickness of 200 nm. The fabricated device offered a spectral response suitable for a blue color filter, exhibiting the center wavelength of approximately 460 nm, the bandwidth approximately 90 nm and the peak transmission 40%. The positional dependence of its performance was examined to find the effective area of 3 x 3 mm(2), where the variation in the relative transmission efficiency and in the center wavelength was less than 10% and 2 nm respectively. Finally, the influence of the angle of the incident beam upon the transfer characteristics of the device was investigated to reveal that the rate of change in the relative transmission was equivalent to about 1.5%/degree.

Color filter based on a subwavelength patterned metal grating.

A color filter incorporating a subwavelength patterned grating in a metal film perforated with a square array of circular apertures on a quartz substrate was accomplished. Its performance was enhanced by applying a dielectric overlay to the grating layer so as to match the refractive indices of the media on either side of it. The device was designed by utilizing the finite-difference time-domain method and implemented by adopting the electron-beam direct-writing technique. Two different devices were fabricated with the structural parameters: the grating height of 50 nm and the pitch of 340 nm for the red color and 260 nm for the green color. For the red color filter the center wavelength was 680 nm and the peak transmission 57%, while for the green color one the center wavelength was 550 nm and the peak transmission 50%. It was confirmed the introduction of the index matching overlay led to an increase of ~15% in the transmission efficiency and helped combine double bands into a single dominant band as well, thereby improving the color selectivity of the filter.

Light extraction enhancement from nano-imprinted photonic crystal GaN-based blue light-emitting diodes.

The nano-imprint lithography method was employed to incorporate wide-area (375 x 330 mum(2)) photonic-crystal (PC) patterns onto the top surface of GaN-based LEDs. When the 280-nm-thick p-GaN was partly etched to ~140 nm, the maximal extraction-efficiency was observed without deteriorating electrical properties. After epoxy encapsulation, the light output of the PC LED was enhanced by 25% in comparison to the standard LED without pattern, at a standard current of 20 mA. By three-dimensional finite-difference time-domain method, we found that the extraction efficiency of the LED tends to be saturated as the etch-depth in the GaN epitaxial-layer becomes larger than the wavelength of the guided modes.