OBJECTIVE To investigate orbital vascular resistance by Doppler velocimetry in patients with steady-state sickle cell anemia, as well as to characterize its relationship with biomarkers of hemolysis. MATERIALS AND METHODS This was a cross-sectional study of two groups: 71 outpatients with sickle cell anemia; and 32 age- and gendermatched, healthy subjects (control group). All participants und...

The advent of the laser as a relatively common tool for flow visualization has stimulated the development of velocimetry techniques based on the use of photosensitive molecules. While a variety of different molecules have been employed for this purpose, they share the common attribute that laser excitation is used to produce a defined pattern of long-lived tracers which are embedded within the ...

Transparent stereolithographic rapid prototyping (RP) technology has already demonstrated in literature to be a practical model construction tool for optical flow measurements such as digital particle image velocimetry (DPIV), laser doppler velocimetry (LDV), and flow visualization. Here, we employ recently available transparent RP resins and eliminate time-consuming casting and chemical curing...

Bidirectional laser Doppler velocimetry (LDV) and fundus photography were applied to investigate the effects of light and darkness on retinal blood flow. Blood flow had increased by an average of 67% after 5 min of darkness. This increase persisted for periods of darkness as long as 80 min (the longest period tested). The magnitude of this elevation, its time course, and its neutralization by t...

Investigation of Relative Importance of Some Error Sources in Particle Image Velocimetry

We present the photoacoustic imaging velocimetry (PAIV) method for flow-field measurement based on a linear transducer array. The PAIV method is realized by using a Q-switched pulsed laser, a linear transducer array, a parallel data-acquisition equipment and dynamic focusing reconstruction. Tracers used to track liquid flow field were real-timely detected, two-dimensional (2-D) flow visualizati...

We report on the dynamics and structure of the turbulent velocity field in a high-Rayleigh-number (Ra = 5.9 x 10(8))thermal convection cell with an aspect ratio of 4. Spectral density functions (measured with laser Doppler velocimetry) indicated the existence of a large-scale periodic component. The long-time mean flow field (measured with particle image velocimetry) revealed that the large-sca...

We suggest an approach to probing intermittency corrections to the Kolmogorov law in turbulent flows based on the autoregressive moving-average modeling of turbulent time series. We introduce an index Υ that measures the distance from a Kolmogorov-Obukhov model in the autoregressive moving-average model space. Applying our analysis to particle image velocimetry and laser Doppler velocimetry mea...