Ultrasound sonication

The other way to introduce fullerenes C60 to biomedium, that we have used, was based on the transfer of these molecules from organic solvent (e.g., toluene) to the water using ultrasound sonication (Scharff et al., 2004). 

It is liquid-liquid reactions involving phase transfer catalysts which generally benefit from the use of ultrasound. Sonication produces homogenisation - i. e. very fine emulsions - which greatly increase the reactive interfacial area and allows faster reaction at lower temperatures. Davidson has reported an example of this with the ultrasonically enhanced saponification of wool waxes by aqueous sodium hydroxide using tetra n-heptyl ammonium bromide as a PTC [124]. 

Ultrasound (sonication) converts AC line voltage to 20-kHz high-frequency electrical energy, which is fed to a converter where, in turn, it is converted to mechanical vibrations. 

Fischer-type chromium carbene complexes of furans underwent Dotz benzannulation with alkynes to provide trisubstituted benzo [, ]furan derivatives. An example used in the synthesis of isodityrosine is depicted in Equation (39) <2005JOC7422>. The efficiency of the reaction could be improved by ultrasound sonication <19990L1721>. 

A similar effect on aryl halides is produced by using a suspension of zinc dust, nickel chloride and sodium iodide in moist hexamethylphosphoramide at 60 C under ultrasound sonication. Chlorobenzene is thus converted to benzene in 64—93% yields. ... 

Fig. 20. Average spatial temperature profiles produced by ultrasound sonications given in tumours implanted in the skeletal muscle of rabbits, (left) Phase difference image showing a localized area of heating, (middle) corresponding temperature profile across the focus (right) profile across the focus with a plastic lens placed in front of the transducer. (Reprinted from ref. 273 by permission of Wiley-Liss, Inc., a subsidiary of John Wiley Sons, Inc., Copyright 1998 John Wiley.)...

The most common extraction techniques for semivolatile and nonvolatile compounds from solid samples that can be coupled on-line with chromatography are liquid-solid extractions enhanced by microwaves, ultrasound sonication or with elevated temperature and pressures, and extraction with supercritical fluid. Elevated temperatures and the associated high mass-transfer rates are often essential when the goal is quantitative and reproducible extraction. In the case of volatile compounds, the sample pretreatment is typically easier, and solvent-free extraction methods, such as head-space extraction and thermal desorption/extraction cmi be applied. In on-line systems, the extraction can be performed in either static or dynamic mode, as long as the extraction system allows the on-line transfer of the extract to the chromatographic system. Most applications utilize dynamic extraction. However, dynamic extraction is advantageous in many respects, since the analytes are removed as soon as they are transferred from the sample to the extractant (solvent, fluid or gas) and the sample is continuously exposed to fresh solvent favouring further transfer of analytes from the sample matrix to the solvent. 

Fig. 29 Schematic illustration of the self-assembly of amphiphilic metallo-supramolecular block copolymers under encapsulation of cargo into micelles and disassembly of the micelles under release of the drug upon ultrasound sonication via dissociation of the metal-ligand complex. Upon cessation of the ultrasonication, the micelles re-assemble again [96]...

Recently, various methods have been proposed to obtain nanocellulosic fibrils from cellulosic fibres. Chemical and enzymatic treatments followed by mechanical disintegration, homogenisation, or ultrasound sonication are being used extensively... 

Highly stable water colloid solution of Cgo fnUerene (maximum concentration 2 mg/mL) was prepared by transfer of Cgo (purity >99.5%) from toluene to water using ultrasound sonication. Analysis of the UV/vis, Raman, FTIR, and SANS spectroscopic data showed that the water colloid solution of Cgo fullerenes contains single Cgo molecules in the hydrated state. However, their clusters and solids (nanocrystallites) have different sizes (1-36 nm in dependence of Qo concentration in water). The aggregation kinetics indicated that the structure of Cgo aggregates could be described as a fractal with a dimension of 1.8-2.0 nm. 

Ultrasound (sonication) This is a chemical-free process to cause cell disruption by inducing cavitation (bubbles) into a solution. The bubbles generate turbulence and pressure differences during both formation and bursting that can lead to rupture of microorganisms. The technique is still under research. 

Kabir, M. E., M. C. Saha, and S. Jeelani. 2007. Effect of ultrasound sonication in carbon nanofibers/polymethane foam composite. Mater. Sci. Eng. A—Struct. Mater. Prop. Microstruct. Proc. 459 111-116. 

From the environmental viewpoint, the solvent used for coating or film-forming materials is important. The macromonomer technique was therefore applied to form a miniemulsion system of PLA-graft copolymers, as a typical example of the use of water as a green solvent. Four MMm macromonomers (m = 4, 6, 8, and 12 Scheme 1) were prepared and used as comonomer. In the copolymerization, BMA or BA was employed as the vinyl monomer (reaction 2, Scheme 1) [41]. Sodium dodecyl sulfate (SDS) and sodium dioctyl sulfosuccinate (PEREX), both anionic, were found to be appropriate surfactants. To form a stable emulsion system, ultrasound sonication was applied to the mixture of comonomers and surfactant in water before the copolymerization. Then, radical copolymerization was carried out (Table 3) [41, 42]. Relevant to the use of water as reaction solvent. Sect. 4 describes the use of green solvents in enzyme-catalyzed polymerizations. 

The most commonly used buffer is phosphate buffer (Na2HP04 + NaH2P04, 100 mM, pH 7) or Tris-HCl buffer (10 mM, pH 7.4). Samples are further diluted with buffer solution in a quantity equivalent to ten times the tissue weight. An ultrasound sonication apparatus should be used to homogenize the sample. In the ease of a solid tissue it is better to use mechanical disruption by a mixer. 

Other conditions ultrasound-sonication other enol-ethers... 

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