Effects Of Ultrasonic Radiation Research Articles

Effects of ultrasonic radiation on induction period and nucleation kinetics of sodium sulfate

The effects of ultrasound on crystal nucleation and particle size distribution of sodium sulfate were investigated via determining the induction period and particle size. Crystal nucleation parameters and equations for primary nucleation were calculated. The experimental results show that the induction time decreases under the ultrasound irradiation, therefore, we can get a shorter induction period at a higher supersaturation level. Based on these observations, the growth mechanism of sodium sulfate is continuous growth because the value of the surface entropy factor f is smaller than 3. The induction period was observed shorter and particle size was smaller when the ultrasonic radiation time increased. Crystal growth improved with the longer crystallization time.

Cavitation effect on chitosan nanoparticle size: A possible approach to protect drugs from ultrasonic stress

The objective of this study was to verify the influence of different modes of ultrasonic radiation on both the mean diameter and the polydispersity index (PI) of chitosan (CH) nanoparticles, which were prepared by means of the ionotropic gelation method. The variations in duration, intensity and mode of cycle of ultrasonic radiation allowed us to highlight several optimal treatments in order to obtain a potential carrier for site-specific drug delivery. Despite the high utility, ultrasound may be a risk factor for sensitive drug-loaded nanoparticles; in order to protect the drug from thermal or mechanical stress, the effects of ultrasonic radiation only on the CH dispersion (instead of the chitosan/tripolyphosphate (TPP) mixture) were studied, without damaging the drug added to the TPP solution. The increase of the wave amplitude, mode of cycle and time of sonication decreased the particle mean diameter; moreover, the mode of cycle showed a greater effect than the other parameters on the PI of the nanoparticle system. Both the mean diameter and the PI of CH nanoparticles increased with increasing CH concentration. The application of ultrasound only on the CH dispersion showed interesting results, particularly in regard to formulations prepared from low and medium molecular weight chitosan.

The ultrasonic effect on the mechanism of cholesterol oxidase production by Brevibacterium sp.

The effects of ultrasonic radiation on cholesterol oxidase production by Brevibacterium sp. are studied in this paper. An ultrasonic wave with low intensity at 20 kHz, 200 W/ cm2 was employed to study the effects of irradiation at different lengths of time on the growth of Brevibacterium sp. cells. The result showed that the production of cholesterol oxidase from Brevibacterium sp. obviously increased, and was about 18.3%, when the culture was radiated for 1 min every 4 h. In order to investigate the action of ultrasonic on cell membrane and to facilitate enzyme excretion, transmission electron microscopy (TEM) was employed. Scanning of the bacterial cells by TEM also first revealed that holes appeared in the cytoplasmic region, then excluded from the cell barrage, and finally self-destructed with higher irradiating dosage.

化学ニッケル‐りんめっきにおける超音波の効果

Effects of ultrasonic radiation on the deposition rate of chemical nickel plating and on the properties of the nickel deposit have been studied. The deposition rate of nickel was increased remarkably by ultrasonic radiation in citrate baths, but no such large increment was obtained in succinate baths. The enhancement of the deposition rate might be attributable to the diffusion controlled process in chemical nickel plating.Ultrasonic radiation also influenced the crystallographic structure and hardness of the nickel deposits, and reduced the P content of the nickel deposits owing to the increased co-deposition of Tl. However, heat-treatment of the nickel deposits resulted in precipitation hardening due to Ni3P formation.The hardness of the deposits decreased with the ultrasonic radiation depending on the P content of the deposits. Changes in the properties of the nickel deposits with ultrasonic radiation was interpreted as a function of the P content of the nickel deposits.

Methods of improving settling of industrial pigment slurries

AbstractAn experimental study on improvement of settling of three industrial pigment slurries, with trade names chrome yellow, molybdate orange and semi‐blacktone iron blue is reported. Three methods for improvement were employed. Additions of common surfactants did not improve settling rate of any slurry. Additions of a flocculating agent with trade name Hercofloc 825.2, on the other hand, improved the settling rates of all three slurries very significantly. Settling of chrome yellow slurries was increased a phenomenally one hundred fold by additions of Hercofloc 825.2. The exposure of the slurries to low frequency (540 kHz and 765 kHz) ultrasonic radiation increased the settling rate as high as six to seven fold. The effects of ultrasonic radiation on the settling of iron blue slurry of various solids concentration, and initial slurry height were investigated. Exposure of the slurry to ultrasonic radiation appears to be a viable and practical method for improving settling of industrial pigment slurries.

Effects of ultrasonic radiation in experimental focal epilepsy in a cat

Effects of ultrasonic radiation in experimental focal epilepsy in a cat

Effects of ultrasonic radiation in experimental focal epilepsy in the cat

Experimental focal epilepsy was induced in thirty-seven cats by subcortical injection of 0.1 ml of alumina cream. Fifteen of these were treated by surgical removal of the epileptogenic focus, twelve by irradiation with focused ultrasound and nine with medication. One died before any therapy could be instituted. Ultrasonic irradiation effectively relieved the animals of the seizures and abnormal EEG patterns by eradication of the epileptogenic focus with less untoward effects and postoperative complications than did surgery. Medical therapy was ineffective. Post-mortem examination of the brains showed grossly that ultrasonic irradiation eradicated the epileptogenic focus without destroying extensively the overlying and adjacent brain tissue and without forming corticodural adhesions. Microscopically, irradiated foci could be distinguished from the surgically treated ones by inter alia absence of trabeculated loose vascular scar tissue and paucity of fibroblasts and collagen fibers.

Effects of ultrasonic radiation on Escherichia coli: Spectrophotometric studies

The heritably altered staining property of E. coli B with vital fluorochrome acridine orange after exposure to ultrasonic radiation is studied spectrophotometrically in the visible and ultraviolet regions. Sustained absorption spectral shifts are observed for bacterial suspensions in vivo immediately after ultrasonic treatment and subsequent staining in the visible and without staining in the ultraviolet regions. An increased uptake of the dye has also been observed after treatment. However, it is observed that the viability is substantially retained and there is no indication of any change in the growth rate or nutritional requirements. The possible role of the nucleic acids in these observed spectral shifts, the significance of these results and their genetic implications are discussed.

Some effects of ultrasonic radiation on normal tissues

Lesions can be produced in many different tissues with ultrasonic irradiation at intensities varying from 1 to 3 watts/sq cm for periods of 1 to 15 minutes. The higher the intensity and the longer the duration of treatment, the more severe were the lesions. Focused ultrasound waves of 37.5 total watts for 5 to 15 minutes produced localized areas of necrosis in liver. Other histologic lesions produced by various intensities and durations of treatment included necrosis, inflammation and edema of skin, subcutaneum, and muscle; degeneration, necrosis and giant cell reaction in testis; necrosis, ulcers, inflammation and hemorrhage in the intestines; and necrosis of bone and hyaline droplet change in renal tubular epithelium. Cavitation, probably due to the accumulation of bubbles of gas, was not observed in livers or other tissues of living animals that were treated. The change was produced in the livers of animals treated in situ after death and in livers removed from the body and treated.

Effects of ultrasonic radiation in Escherichia coli B using fluorochrome acridine orange as a vital stain.

Effects of Ultrasonic Radiation in Escherichia coli B using Fluorochrome Acridine Orange as a Vital Stain

Effects of Ultrasonic Radiation on the Viscosity of Cellulose Solutions

Effects of Ultrasonic Radiation on the Viscosity of Cellulose Solutions

Effects of ultrasonic radiation on growth and fermentation in the yeast, Saccharomyces cerevisiae

Samples from young and older cultures of S. cerevisiae, Strain 15.56, suspended to standard optical density in buffer solution, were exposed to CW or pulsed ultrasonic radiation for different periods. Frequency was i Mc; a plastic lens focussed the beam into a region in which average intensity, over an area of 0.78 cm 2, was about 10.5 W/cm 2. Pulsed radiation, repetition-rate 600/sec, was applied in 25% and 50% duty cycles. Effects were estimated by determination of fermentation rate and growth behaviour, in special flasks. Ten minutes' irradiation of young cells with CW ultrasound produced greater effects than longer exposure to pulsed radiation. Fermentation was markedly inhibited; the lag phase of cultures from irradiated cells was prolonged, and the relative growth rate depressed. Counts of killed cells (stained with eosin) showed that inhibition of fermentation could be accounted for on the basis of population reduction. This decrease in effective inoculum explains also the prolonged lag phase, but not the depressed growth rates. Growth inhibition may be caused by direct, sublethal damage to surviving cells, or by the production of toxic substances in the medium during irradiation. Cells from older cultures were essentially unaffected by radiation. Heating of the suspension is not the factor causing damage; other physical effects were not evaluated. The ineffectiveness of pulsed radiation is attributed to the provision of recovery periods between pulses.

Effects of Ultrasonic Radiation upon the Eye

Experiments have been made with ox eyes immersed in water. Ultrasonic radiation from a three megacycle per second source was focused at various points inside the eyes. Permanent localized opacities have been produced in the lens (cataracts) and on the cornea. The manner in which their production depends upon intensity and exposure time indicates that the effect is probably due to heating produced by absorption in the focal region. Temperature measurements made with a small thermocouple inserted in the lens at the sound focal region confirm this hypothesis.

The mechanism of the lethal effects of ultrasonic radiation

The mechanism of the lethal effects of ultrasonic radiation