The earlier report that the frequency dependence of ultrasonic absorption of mammalian testis memicked a single relaxation process is explained as an effect of ultrasonic beam width upon the transient thermoelectric technique. More detailed measurements show that the frequency dependence of the ultrasonic absorption in testis is much the same as the attenuation in other soft tissues, viz., a pr...

The ultrasonic absorption of sickle cells was compared with the morphological changes in these cells are produced by varying oxygen tensions and pH. A decrease in oxygen tension caused increased sickling and an increase in the ultrasonic absorption of the blood. An increase in pH reduced the ultrasonic absorption and decreased sickling. These findings indicate that ultrasonic absorption can det...

This paper constitutes a progress rersort on the develol•ment of an ultrasonic instrument for detecting microstructure. The principle of operation of the device (designated by the term "ultrasonic microscope") is as follows: The specimen is imbedded in a liquid, which closely matches it in acoustic impedance, and is irradiated with sho•t pulses of highdreqnency hound. Some of the ultrasonic ene...

A series of materials used for oil absorption based on cellulose fiber grafted with butyl acrylate (BuAc) have been prepared by radical polymerization under ultrasonic waves processing. Effects of ultrasonic dose for the maximum graft yield were considered. The dependency of optimum conditions for oil absorption rate on parameters such as ultrasonic processing time and ultrasonic power were als...

The ultrasonic absorption of aqueous solutions of salmon sperm deoxyribose nucleic acid (DNA), molecular weight of the order of 106, was determined as a function of pH in the neutral and acidic regions over the frequency range 5-50 MHz at 25øC. Tile viscous relaxation frequencies appear to be well below 1 MHz. At neutral pH values, viscosity and molecular conformation appear to contribute littl...

in this paper, the ultrasonic absorption of amino acids was measured using a small cylindrical resonator at physiological ph and 25°c and a concentration of 0.1. m. the absorption of mixtures of some amino acids was also measured. in the case of cysteine-histidine, the absorption of mixtures is much larger (more than twice) than the summation of absorption of the individual amino acid. this may...

The ultrasonic amlfiiLudc absorl)liou coelhcient has Iveen determined in aqueous solutions of four molecular weights (73 000, 186 000, 370 000, and 2 {DO 000) of dextran, a linear • (! --• 6) anhydroglucoae polysaccharide of biological origin, over the frequency range 3-69 Mc/sec at 22øC. It is found that the concentrationfree absorption spectrum exhibits a remarkable similarit)' to that of aqu...

The study described herein was undertaken to determine the role of proteins, in general, and collagen, in particular, in the observed absorption and speed of ultrasound in biological tissues. It had earlier been observed that ultrasonic absorption in tissues occurs at the macromolecular level, •'z though an additional contribution to attenuation arises from tissue structural features. a Each of...