Non-Intrusive Temperature Measurements Using Microscale Visualization Techniques

lPIV is a widely accepted tool for making measured. This method allows simultaneous non-intrusive temperature and velocity measurements in integrated accurate measurements in microscale flows. The particles cooling systems and lab-on-a-chip devices. that are used to seed the flow, due to their small size, undergo Brownian motion which adds a random noise component to the measurements. Brownian motion intro- duces an undesirable error in the velocity measurements, but also contains valuable temperature information. A PIV algorithm which detects both the location and broadening of the correlation peak can measure velocity as well as temperature simultaneously using the same set of images. The approach presented in this work eliminates the use of the calibration constant used in the literature (Hohreiter et al. in Meas Sci Technol 13(7):1072–1078, 2002), mak- ing the method system-independent, and reducing the uncertainty involved in the technique. The temperature in a stationary fluid was experimentally measured using this technique and compared to that obtained using the particle tracking thermometry method and a novel method, low image density PIV. The method of cross-correlation PIV was modified to measure the temperature of a moving fluid. A standard epi-fluorescence lPIV system was used for all the measurements. The experiments were conducted using spherical fluorescent polystyrene-latex particles suspended in water. Temperatures ranging from 20 to 80°C wer

NRG/RTOG 0837: Randomized, Phase II, Double-Blind, Placebo-Controlled Trial of Chemoradiation With or Without Cediranib in Newly Diagnosed Glioblastoma

BACKGROUND: A randomized, phase II, placebo-controlled, and blinded clinical trial (NCT01062425) was conducted to determine the efficacy of cediranib, an oral pan-vascular endothelial growth factor receptor tyrosine kinase inhibitor, versus placebo in combination with radiation and temozolomide in newly diagnosed glioblastoma. METHODS: Patients with newly diagnosed glioblastoma were randomly assigned 2:1 to receive (1) cediranib (20 mg) in combination with radiation and temozolomide; (2) placebo in combination with radiation and temozolomide. The primary endpoint was 6-month progression-free survival (PFS) based on blinded, independent radiographic assessment of postcontrast T1-weighted and noncontrast T2-weighted MRI brain scans and was tested using a 1-sided RESULTS: One hundred and fifty-eight patients were randomized, out of which 9 were ineligible and 12 were not evaluable for the primary endpoint, leaving 137 eligible and evaluable. 6-month PFS was 46.6% in the cediranib arm versus 24.5% in the placebo arm ( CONCLUSIONS: This study met its primary endpoint of prolongation of 6-month PFS with cediranib in combination with radiation and temozolomide versus placebo in combination with radiation and temozolomide. There was no difference in overall survival between the 2 arms

Visualization of Convection Patterns Near an Evaporating Meniscus using micro-PIV

Experimental visualizations of the three dimensional (3D) convection patterns generated near an evaporating meniscus in horizontally oriented capillary tubes are presented. These patterns are caused due to the differential evaporation along the meniscus. In this study, transparent capillary tubes with refractive index close to that of the evaporating liquid were used to minimize refraction effects and obtain velocity vectors near the walls. Polystyrene fluorescent particles of 0.5 lm diameter suspended in methanol were used to make the measure- ments in tubes of 75, 200 and 400 lm diameter. For the 75 lm tube, gravity was observed to have no effect on the flow patterns and an axisymmetric counter-rotating vortex pair was present along the horizontal and vertical center planes, suggesting the presence of a toroidal vortex near the meniscus. With an increase in tube size, buoyancy effects became apparent as the axisymmetric pattern broke down. A counter-rotating symmetric vortex pair was observed in the horizontal center plane, whereas in the vertical center plane, a single vortex dominated the flow and pushed the secondary vortex to a corner. Particle streak and lPIV images were obtained in multiple horizontal planes and a vertical center plane to understand this 3D flow behavior