Photoelastic force measurements in granular materials

Photoelastic techniques are used to make both qualitative and quantitative measurements of the forces within idealized granular materials. The method is based on placing a birefringent granular material between a pair of polarizing filters, so that each region of the material rotates the polarization of light according to the amount of local of stress. In this review paper, we summarize past work using the technique, describe the optics underlying the technique, and illustrate how it can be used to quantitatively determine the vector contact forces between particles in a 2D granular system. We provide a description of software resources available to perform this task, as well as key techniques and resources for building an experimental apparatus

Speech Communication

Contains table of contents for Part V, table of contents for Section 1, reports on six research projects and a list of publications.C.J. Lebel FellowshipDennis Klatt Memorial FundNational Institutes of Health Grant R01-DC00075National Institutes of Health Grant R01-DC01291National Institutes of Health Grant R01-DC01925National Institutes of Health Grant R01-DC02125National Institutes of Health Grant R01-DC02978National Institutes of Health Grant R01-DC03007National Institutes of Health Grant R29-DC02525National Institutes of Health Grant F32-DC00194National Institutes of Health Grant F32-DC00205National Institutes of Health Grant T32-DC00038National Science Foundation Grant IRI 89-05249National Science Foundation Grant IRI 93-14967National Science Foundation Grant INT 94-2114

Effect of Fluconazole Prophylaxis on Candidiasis and Mortality in Premature Infants

IMPORTANCE: Invasive candidiasis in premature infants causes mortality and neurodevelopmental impairment. Fluconazole prophylaxis reduces candidiasis, but its effect on mortality and the safety of fluconazole is unknown. OBJECTIVE: To evaluate the efficacy and safety of fluconazole in preventing death or invasive candidiasis in extremely low-birth-weight infants. DESIGN, SETTING, AND PATIENTS: This study was a randomized, blinded, placebo-controlled trial of fluconazole in premature infants. Infants weighing less than 750 g at birth (N = 361) from 32 neonatal intensive care units (NICUs) in the United States were randomly assigned to receive either fluconazole or placebo twice weekly for 42 days. Surviving infants were evaluated at 18 to 22 months corrected age for neurodevelopmental outcomes. The study was conducted between November 2008 and February 2013. INTERVENTIONS: Fluconazole (6 mg/kg of body weight) or placebo. MAIN OUTCOMES AND MEASURES: The primary end point was a composite of death or definite or probable invasive candidiasis prior to study day 49 (1 week after completion of study drug). Secondary and safety outcomes included invasive candidiasis, liver function, bacterial infection, length of stay, intracranial hemorrhage, periventricular leukomalacia, chronic lung disease, patent ductus arteriosus requiring surgery, retinopathy of prematurity requiring surgery, necrotizing enterocolitis, spontaneous intestinal perforation, and neurodevelopmental outcomes—defined as a Bayley-III cognition composite score of less than 70, blindness, deafness, or cerebral palsy at 18–22-months corrected age. RESULTS: Among infants receiving fluconazole, the composite primary end point of death or invasive candidiasis was 16% (95% CI, 11%–22%) vs 21% in the placebo group (95% CI, 15%–28%; odds ratio 0.73 [95% CI 0.43–1.23]; P=.24; treatment difference −5% [95% CI, −13%–3%]). Invasive candidiasis occurred less frequently in the fluconazole group (3% [95% CI, 1%–6%] vs the placebo group (9% [95% CI, 5%–14%]; P=.02; treatment difference −6% [95% CI, −11%–−1%]). The cumulative incidences of other secondary outcomes were not statistically different between groups. Neurodevelopmental impairment did not differ between the groups (fluconazole 31% [95% CI, 21–41%] vs placebo, 27% [95% CI, 18–37%]; P=.60; treatment difference 4% [95% CI, −10–17%]). CONCLUSIONS AND RELEVANCE: Among infants with a birth weight of less 750 g, 42 days of fluconazole prophylaxis compared with placebo did not result in a lower incidence of the composite of death or invasive candidiasis. These findings do not support the universal use of prophylactic fluconazole in extremely-low-birth-weight infants. TRIAL REGISTRATION: ClinicalTrials.gov number NCT0073453