Measurement of composite shrinkage using a fibre optic Bragg grating sensor.

Fibre Bragg grating is used to determine resin-based composite shrinkage. Two composite resins (Freedom from SDI and Z100 from 3M) were tested to determine the polymerization contraction behaviour. Each sample of resin was prepared with an embedded fibre Bragg grating. A LED activation unit with wavelength from 430 nm to 470 nm (Dabi Atlante) was used for resin polymerization. The wavelength position of the peak in the optical reflection spectra of the sensor was measured. The wavelength shift was related to the shrinkage deformation of the samples. Temperature and strain evolution during the curing phase of the material was monitored. The shrinkage in the longitudinal direction was 0.15 +/- 0.02% for resin Z100 (3M) and 0.06+/-0.01% for Freedom (SDI); two-thirds of shrinkage occurred after the first 50 s of illumination.

Hypocholesterolemia, hypertriglyceridemia, suicide, and suicide ideation in children hospitalized for psychiatric diseases.

To assess relationships of total plasma cholesterol (TC) and triglyceride (TG) values to suicide, suicide ideation, and hospitalization for psychiatric disease, we studied 220 children, ages 5 to 18 y, hospitalized with affective, adjustment, disruptive, anxiety, schizophrenic, other, and organic psychiatric disorders. The 135 male and 85 female patients had higher TG values (p = 0.0001 and 0.0003, respectively) and higher Quetelet Indices (p = 0.0001 and 0.003, respectively) than the 732 male and 316 female schoolchild controls; male patients had higher TC values than male controls (p = 0.014). Substance abuse in patients was an independent inverse determinant of TC value (p = 0.05); TG value correlated positively with alcohol use (p < or = 0.1) and substance abuse (p < 0.05). After covariance adjustment for age, race, sex, and Quetelet, children having adjustment disorders with depression had much lower covariance-adjusted TC value than control schoolchildren (3.91 versus 4.29 mmol/L, p = 0.003), whereas those with disruptive behavior with oppositional defiant disorder had much higher adjusted TC value (5.09 mmol/L, p = 0.0001). After covariance adjusting for age, race, sex, Quetelet, cigarette smoking, alcohol use, and substance abuse, children having adjustment disorders with concomitant depression had the highest group suicide tendencies (attempts and ideation) and the lowest covariance-adjusted TC value (4.03 mmol/L). Conversely, children having disruptive behavior with attention deficit hyperactivity disorder or disruptive behavior with oppoistional defiant disorder had 50% lower suicide index than those with adjustment disorders with concomitant depression and higher adjusted TC levels (4.45 and 5.12 mmol/L, p = 0.0003).(ABSTRACT TRUNCATED AT 250 WORDS)