High-Q suspended optical resonators in 3C silicon carbide obtained by thermal annealing.

We fabricate suspended single-mode optical waveguides and ring resonators in 3C silicon carbide (SiC) that operate at telecommunication wavelength, and leverage post-fabrication thermal annealing to minimize optical propagation losses. Annealed optical resonators yield quality factors of over 41,000, which corresponds to a propagation loss of 7 dB/cm, and is a significant improvement over the 24 dB/cm in the case of the non-annealed chip. This improvement is attributed to the enhancement of SiC crystallinity and a significant reduction of waveguide surface roughness, from 2.4 nm to below 1.7 nm. The latter is attributed to surface layer oxide growth during the annealing step. We confirm that the thermo-optic coefficient, an important parameter governing high-power and temperature-dependent performance of SiC, does not vary with annealing and is comparable to that of bulk SiC. Our annealing-based approach, which is especially suitable for suspended structures, offers a straightforward way to realize high-performance 3C-SiC integrated circuits.

Bacterial Endocarditis Caused by Lactobacillus acidophilus Leading to Rupture of Sinus of Valsalva Aneurysm.

Lactobacillus acidophilus rarely causes bacterial endocarditis, because it usually resides in the mucosa of the vagina, gastrointestinal tract, and oropharynx. Moreover, sinus of Valsalva aneurysms are rare cardiac anomalies, either acquired or congenital. We present the case of a middle-aged man whose bacterial endocarditis, caused by Lactobacillus acidophilus, led to an aneurysmal rupture of the sinus of Valsalva into the right ventricular outflow tract. The patient underwent successful surgical repair, despite numerous complications and sequelae.

Comparison of microdebrider subcapsular tonsillectomy to harmonic scalpel and electrocautery total tonsillectomy.

OBJECTIVE: The aim of this study was to compare microdebrider subcapsular tonsillectomy (MST) with total tonsillectomies either by harmonic scalpel (TTH) or electrocautery (TTE) in children with obstructive sleep-disordered breathing from tonsillar hypertrophy. DESIGN: Retrospective review of prospectively collected data. SETTING: Tertiary academic hospital. PATIENTS: Eighty consecutive children with obstructive sleep-disordered breathing from tonsillar hypertrophy who underwent MST between January and April of 2003 were compared with a smaller historical cohort of 25 patients who underwent TTEs and TTHs from January to December of 2001. MAIN OUTCOME MEASURES: Primary: days to no narcotic pain medicine use and days to solid food intake; secondary: estimated blood loss, surgical time, and postoperative complications. RESULTS: Fifty-four patients who underwent MSTs and 25 patients who underwent total tonsillectomies met study criteria for a total of 79 patients. The cohorts showed no significant demographic differences between groups. The MST group had a significantly shorter duration of pain medicine use (3.7 +/- 0.5 days) than the TTE (7.0 +/- 0.6 days) or TTH groups (6.8 +/- 0.7 days; P < .001). The MST group (3.5 +/- 0.6 days) and the TTH group (3.6 +/- 0.8 days) achieved solid food intake faster than the TTE group (5.4 +/- 0.7 days; P = 0.004). There was a significantly higher estimated blood loss with the MST group (38.8 +/- 6.1 mL) than the TTH group (19 mL +/- 8.2) and the TTE group (15.1 +/- 7.4 mL; P < .001). TTH (27.3 +/- 3.1 minutes) took longer than MST (20.3 +/- 2.3 minutes) and TTE (21.9 +/- 2.8 minutes; P = .018). CONCLUSION: Microdebrider subcapsular tonsillectomy is valuable in treatment of children with tonsillar hypertrophy because of the decreased pain medicine use and more rapid return to solid food.