No abstract

The kinematics of tongue dorsum movements in speech were studied with pulsed ultrasound to assess similarities in the voluntary control of the speech articulators and the limbs. The stimuli were consonant--vowel syllables in which speech rate and stress were varied. The kinematic patterns for tongue dorsum movements were comparable to those observed in the rapid movement of the arms and hands. The maximum velocity of tongue dorsum raising and lowering was correlated with the extent of the gesture. The slope of the relationship differed for stressed and unstressed vowels but was unaffected by differences in speech rate. At each stress level the correlation between displacement and peak velocity was accompanied by a relatively constant interval from the initiation of the movement to the point of maximum velocity. The data are discussed with reference to systems that can be described with second-order differential equations. The increase in the slope of the displacement/peak-velocity relationship for unstressed versus stressed vowels is suggestive of a tonic increase in articulator stiffness. Variations in displacement are attributed to the level of phasic activity in the muscles producing the gesture.

A computerized system for the measurement of tongue dorsum movements with pulsed echo ultrasound is described. The presentation focuses on technical and methodological considerations in the on-line acquisition of vertical tongue movement information, its digital processing and display. Problems associated with transducer placement, peak detection, data averaging, and curve fitting are considered, and validation procedures based on x ray and indicators of measurement reliability are reported. The discussion centers on advantages and disadvantages of the technique and its applications.

The paper presents development and experimental validation of a real-time health monitoring and nondestructive evaluation (NDE) method for residual life prediction of ductile-alloy structures. Application areas include fatigue crack damage in mechanical structures such as those in aircraft, surface ship, submarines, civil infrastructures, and power plants. The technical approach relies on fusion of heterogeneous information derived from physics-based models of fatigue damage and realtime sensor data. This ultrasonic-sensor-based NDE method requires theoretical formulation and experimental validation: (i) a stochastic damage model under fatigue crack initiation and propagation; and (ii) filter algorithms for on-line damage estimation and remaining life. The analytical part of the work is supported by laboratory experimentation on a special-purpose fatigue test apparatus that is equipped with computer-based ultrasonic, optical, and mechanical sensing devices.

Personalized medicine holds great promise for cancer treatment, with the potential to address challenges associated with drug sensitivity and interpatient variability. Circulating tumor cells (CTC) can be useful for screening cancer drugs as they may reflect the severity and heterogeneity of primary tumors. Here we present a platform for rapidly evaluating individualized drug susceptibility. Treatment efficacy is evaluated directly in blood, employing a relevant environment for drug administration, and assessed by comparison of CTC counts in treated and control samples. Multiple drugs at varying concentrations are evaluated simultaneously to predict an appropriate therapy for individual patients.