Latching operation in a tunable wavelength filter using Si sampled grating waveguide with ferroelectric liquid crystal cladding.

A tunable wavelength filter fabricated with a latching function is proposed. The proposed tunable wavelength filter consists of a silicon sampled grating waveguide and ferro-electric liquid crystal (FLC) cladding. The sampled grating waveguide in a silicon-on-insulator (SOI) wafer achieved narrower stop bands than that with the conventional uniform grating structure. Enhanced wavelength shift was also obtained due to the increased effect in FLC by using a thinner silicon core. Bistable switching operation with the fabricated device, which was latching without state-sustaining power, was successfully demonstrated. Its switching and latching characteristics are also reported.

A study on bone mineral density in patients with Crohn's disease.

Decreased bone mineral density is a complication to which we should always pay attention in the treatment of Crohn's disease (CD). However, there is still no clear consensus with regard to evaluation methods and the appropriate observation period for its detection. In the present study, we measured the bone mineral density of 30 CD patients who were treated at the outpatient clinic of our institution and investigated its relationship with various clinical characteristics including sex, age, duration of illness, history of enterectomy, total steroid consumption, body weight, and body mass index (BMI) and with bone metabolism markers. A decreased bone mineral density was detected in 9 patients (30%). The bone mineral density did not correlate with total steroid consumption, but showed a negative correlation with the Crohn's disease activity index (CDAI).When bone metabolism markers were investigated, the bone mineral density showed a negative correlation with Glu-osteocalcin (Glu-OC) and serum type I collagen cross-linked N-telopeptide (NTx) in patients with a low bone mineral density. Based on these results, the decrease of bone mineral density in CD patients was considered to the underlying disease itself. Therefore, control of disease activity is very important in CD patients, and periodic measurement of bone mineral density in combination with bone mineral markers (Glu-OC and serum NTx) may be useful for predicting a decrease of bone mineral density.