ULTRASOUND: Its Chemical, Physical and Biological Effects
01 Feb 1990-Journal of the Acoustical Society of America (VCH Publishers)-Vol. 87, Iss: 2, pp 919-920
About: This article is published in Journal of the Acoustical Society of America.The article was published on 1990-02-01. It has received 1206 citations till now. The article focuses on the topics: Sonoluminescence & Ultrasound.
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TL;DR: Third-generation delivery systems target their effects to skin's barrier layer of stratum corneum using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound for delivery of macromolecules and vaccines.
Abstract: Transdermal drug delivery has made an important contribution to medical practice, but has yet to fully achieve its potential as an alternative to oral delivery and hypodermic injections. First-generation transdermal delivery systems have continued their steady increase in clinical use for delivery of small, lipophilic, low-dose drugs. Second-generation delivery systems using chemical enhancers, noncavitational ultrasound and iontophoresis have also resulted in clinical products; the ability of iontophoresis to control delivery rates in real time provides added functionality. Third-generation delivery systems target their effects to skin's barrier layer of stratum corneum using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound. Microneedles and thermal ablation are currently progressing through clinical trials for delivery of macromolecules and vaccines, such as insulin, parathyroid hormone and influenza vaccine. Using these novel second- and third-generation enhancement strategies, transdermal delivery is poised to significantly increase its impact on medicine.
2,595 citations
TL;DR: Various aspects of nanoparticle formulation, characterization, effect of their characteristics and their applications in delivery of drug molecules and therapeutic genes are reviewed.
Abstract: For the past few decades, there has been a considerable research interest in the area of drug delivery using particulate delivery systems as carriers for small and large molecules. Particulate systems like nanoparticles have been used as a physical approach to alter and improve the pharmacokinetic and pharmacodynamic properties of various types of drug molecules. They have been used in vivo to protect the drug entity in the systemic circulation, restrict access of the drug to the chosen sites and to deliver the drug at a controlled and sustained rate to the site of action. Various polymers have been used in the formulation of nanoparticles for drug delivery research to increase therapeutic benefit, while minimizing side effects. Here, we review various aspects of nanoparticle formulation, characterization, effect of their characteristics and their applications in delivery of drug molecules and therapeutic genes.
1,385 citations
TL;DR: In this paper, the synthesis of metallic glass powders using the microscopically extreme (yet macroscopically mild) conditions induced by high-intensity ultrasound was described, and the results showed that metallic glass powder is a highly active catalyst for the Fischer-Tropsch hydrogenation of carbon monoxide and for hydrogenolysis and dehydrogenation of saturated hydrocarbons.
Abstract: AMORPHOUS metallic alloys ('metallic glasses') lack long-range crystalline order and have unique electronic, magnetic and corrosion-resistant properties1–3. Their applications include use in power-transformer cores, magnetic storage media, cryothermometry and corrosion-resistant coatings. The production of metallic glasses is made difficult, however, by the extremely rapid cooling from the melt that is necessary to prevent crystallization. Cooling rates of about 105 to 107 K s−1 are generally required; for comparison, plunging red-hot steel into water produces cooling rates of only about 2,500 K s−1. Metallic glasses can be formed by splattering molten metal on a cold surface using techniques such as gun, roller or splat quenching4,5. Acoustic cavitation is known to induce extreme local heating in otherwise cold liquids, and to provide very rapid cooling rates6–11. Here we describe the synthesis of metallic-glass powders using the microscopically extreme (yet macroscopically mild) conditions induced by high-intensity ultrasound. The sonolysis of iron pentacarbonyl, a volatile organometallic compound, produces nearly pure amorphous iron. This amorphous iron powder is a highly active catalyst for the Fischer–Tropsch hydrogenation of carbon monoxide and for hydrogenolysis and dehydrogenation of saturated hydrocarbons.
1,149 citations
01 Jan 1992
TL;DR: The soil organic matter (SOM) pool encompasses plant, animal, and microbial residues in all stages of decay and a diversity of heterogeneous organic substances intimately associated with inorganic soil components.
Abstract: The soil organic matter (SOM) pool encompasses plant, animal, and microbial residues in all stages of decay and a diversity of heterogeneous organic substances intimately associated with inorganic soil components. The soil microbiota and fine roots may also be considered part of the SOM pool. The turnover of the different SOM components varies continuously due to the complex interaction of biological, chemical, and physical processes in soil. The complexity of SOM and its importance to soil fertility have challenged generations of soil scientists, and numerous studies, of which some date back more than two centuries (see historical review in Kononova, 1961), have covered a vast array of aspects of SOM.
1,095 citations
TL;DR: This tutorial review provides examples of how the chemical and physical effects of high intensity ultrasound can be exploited for the preparation or modification of a wide range of nanostructured materials.
Abstract: High intensity ultrasound can be used for the production of novel materials and provides an unusual route to known materials without bulk high temperatures, high pressures, or long reaction times. Several phenomena are responsible for sonochemistry and specifically the production or modification of nanomaterials during ultrasonic irradiation. The most notable effects are consequences of acoustic cavitation (the formation, growth, and implosive collapse of bubbles), and can be categorized as primary sonochemistry (gas-phase chemistry occurring inside collapsing bubbles), secondary sonochemistry (solution-phase chemistry occurring outside the bubbles), and physical modifications (caused by high-speed jets or shock waves derived from bubble collapse). This tutorial review provides examples of how the chemical and physical effects of high intensity ultrasound can be exploited for the preparation or modification of a wide range of nanostructured materials.
829 citations