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Biomedical subjects

I Bankman

Publications and source records attributed to I Bankman.

4 recordsLinked to original sources
PubMed2000

Analytical model of Doppler spectra of coherent light backscattered from rotating cones and cylinders.

The interaction between a rotating object and laser beams has been studied in the field of laser Doppler velocimetry, where two incident laser beams are focused on one small spot of the rotating surface and interferometry is used. In the case of a single incident laser beam illuminating a relatively large area of the rotating surface, both the Doppler broadening and the reflected-power level are dictated by points distributed over a wide curved area at varying angles of incidence. An analytical model of spectra in backscatter from cones and cylinders rotating around their axes is presented. This analytical solution may contribute to laser Doppler velocimetry as well as ladar applications.

Laser-Doppler Flowmetry↗
PubMed1993

Automatic EEG spike detection: what should the computer imitate?

We conducted a study to explore how electroencephalographers (EEGers) read EEGs and reach clinical impressions based upon them. Eight EEGers and a rule-based computerized "spike" detector marked epileptiform discharges ("EDs") in 12 test records. Of all marked events, 18% were marked by all readers and 38% were marked by only one reader. Readers agreed on basic clinical features of the records, such as whether a record demonstrated EDs, the rank order of ED sources by location, and the ranking of test records in order of the number of EDs detected. Readers marked records in a consistent pattern that was independent of an objective measure of expertise and experience. Our computerized ED detector had lower sensitivity and selectivity than human readers, but either parameter could be adjusted to be comparable to human EEGers at the expense of the other. We propose that EEGers employ reproducible, quantitatively different styles of reading EEG tracings to reach qualitatively similar clinical impressions. In practice, EDs are not absolutely defined, but appear to represent a continuum of activity which lends itself better to description and rank ordering than to absolute quantitation. More than just counting EDs, a successful computerized ED detector should be adaptable to the style of individual readers in order to help them efficiently formulate their clinical impressions.

Brain↗
PubMed1989

Effect of positive nasal pressure on upper airway pressure-flow relationships.

To determine the influence of changes in nasal pressure (Pn) on airflow mechanics in the upper airway, we examined the effect of elevations in Pn on upper airway resistance and critical pressure (Pcrit) during stage I/II sleep in six patients with obstructive sleep apnea. When Pn was elevated above a Pcrit, periodic occlusions of the upper airway were eliminated and inspiratory airflow limitation was demonstrated by the finding that inspiratory airflow (VI) became maximal (VImax) and independent of fluctuations in hypopharyngeal pressure (Php) when Php fell below a specific Php (Php'). As Pn was elevated, VI vs. Php demonstrated 1) marked decreases in early and late inspiratory resistances from 75.9 +/- 34.7 and 54.6 +/- 19.0 to 8.0 +/- 1.7 and 7.6 +/- 1.6 cmH2O.l-1.s (P less than 0.05), respectively, and 2) increases in early and late inspiratory Php' to levels that exceeded Pcrit by 3.0 +/- 0.6 and 3.1 +/- 0.7 cmH2O, respectively, at the highest level of Pn applied (P less than 0.01). This latter finding suggests that elevations in Pn result in increases in Pcrit. We suggest that elevations in Pn produce distinct alterations in upper airway resistance and collapsibility, which may influence oppositely the level of airflow through the upper airway during sleep.

Adult↗