Ultrasound devices for

Commercial ultrasound devices for high-throughput analysis... 

Figure 2.4. Commercial discrete devices for chemical reactions assisted by ultrasound probes. (A) Rosett cell, (B) indented cell, (C) Suslick cell and (D) cup horn.

One salient example of the need for degassing in the clinical field and of the effectiveness of ultrasound for this purpose is a prototype of ultrasonic micro-degassing device for portable dialysis systems. The bubbles inside these systems reduce the effective exchange surface area, which is extremely important here [104]. 

Types of devices for ultrasound-assisted slurry formation... 

In relation to applioation duration, most ultrasonio instruments utilize either pulsed (tone-burst or broad-band pulses) or continuous-wave US (Fig. 9.4). Ultrasound pulses are by far the most widely used choice as pulses are easily applied, measurements are rapid and non-invasive, and the ultrasound device can be readily automated. Continuous-wave teohniques have been traditionally used for highly aoourate measurements in speoialized research laboratories. 

After a brief description of the cavitation phenomenon and commercially available devices for the production of ultrasound, this chapter discusses its principal applications... 

Reisse and co-workers [147-149] were the first to describe a novel device for the production of metal powders using pulsed sonoelectrochemical reduction. This device exposes only the flat circular area at the end of the sonic tip to the electrodeposition solution. The exposed area acts as both cathode and ultrasound emitter, named by Reisse et al. as sonoelectrode . A pulse of electric current produces a high density of fine metal nuclei. This is immediately followed by a burst of ultrasonic energy that removes the metal particles from the cathode, cleans the surface of the cathode, and replenishes the double layer with metal cations by stirring the solution. In [145], a list is given of chemically pure fine crystalline powders, mostly metals or metallic alloys, prepared by this method, with particle sizes varying between 10 and 1000 run depending on deposition conditions. 

L-selectin ligand-specific USCA could be a candidate for an indirect method of lymphography for the safe and less-invasive ultrasonic identification of lymph nodes, e.g., when performing a biopsy. Lymph node-targeted microbubbles can be detected easily with any ultrasound device that has color Doppler capabilities. 

The determination of local intensities is quite difficult, and ultrasound devices are mostly characterized by calorimetric measurements. Sound-pressure measurements and methods for determining the local intensity with coated thermocouples or by chemical means are still under development. 

It might be expected that improved ultrasound technology and less expensive ultrasound devices will help to spread the use of this technology and to reduce expensive and unnecessary CT and MRI examinations. The use of contrast agents opens totally new prospects within the foreseeable future, on the one hand, and represents a challenge for every sonographer, on the other. 

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