Investigation of Nonlinear Optical Processes in Mercury Sulfide Quantum Dots.

The authors report the third-harmonic generation, nonlinear refraction, and nonlinear absorption in HgS quantum dot (QD) suspensions and films using the nanosecond and femtosecond pulses. High conversion efficiency (7 × 10) towards the third harmonic (TH) of the 900-1700 nm, 150 fs laser in the thin (70 nm) films containing HgS QDs deposited on the glass substrates is obtained. The authors analyze spectral dependencies of the TH, nonlinear refractive indices, and nonlinear absorption coefficients of QDs in the 500-1700 nm range and discuss the relation between the TH process and the low-order nonlinear optical properties of these quantum dots.

Nonlinear Absorption and Refraction of Picosecond and Femtosecond Pulses in HgTe Quantum Dot Films.

We report measurements of the saturated intensities, saturable absorption, and nonlinear refraction in 70-nm thick films containing 4 nm HgTe quantum dots. We demonstrate strong nonlinear refraction and saturable absorption in the thin films using tunable picosecond and femtosecond pulses. Studies were carried out using tunable laser pulses in the range of 400-1100 nm.

Fall of platelet count in children with traumatic brain injury: is it of value?

Objective: Trauma is the leading cause of mortality and morbidity among young age groups in Saudi Arabia and developed countries. This study aimed to evaluate the fall of platelet count in children with traumatic brain injury (TBI) as a potential predictor for clinical severity and outcome.

Methods: Totally 74 patients with TBI were admitted to the Pediatric Intensive Care Unit (PICU) of our hospital from the beginning of January 2008 to the end of March 2010 (27 months).

Traumatic brain injury in pediatric age group; predictors of outcome in Pediatric Intensive Care Unit.

Objective: To determine predictors for outcomes of traumatic brain injury (TBI) in infants and children younger than twelve years admitted to our pediatric intensive care units (PICU).

Methods: This is a retrospective cohort study from 2004-5, done at the PICU of King Fahad Hofuf Hospital, Eastern Province, Saudi Arabia. One hundred and six patients with TBI; 65 boys and 41 girls ages 12 or under, with a mean age of 5.