Ultrasound gel

Insertion of a tampon is not necessary for adequate evaluation and may even distort vaginal anatomy (Fig. 12.6a). Instead, evaluation can be improved by filling and distending the vagina with ultrasound gel (Fig. 12.6b). 

There is also no agreement on opacification of the vagina in the literature. Usually ultrasound gel is instilled, which is an easy to handle and well tolerated contrast medium. Delineation of the entire vagina and especially of the posterior fornix and posterior wall is always achieved [24,30]. In addition, during Valsalva s maneuver the gel in the vagina is emptied passively and thus the movement of the organ itself is not impeded [21]. In this regard rubber tubes are not a recommended alternative [18]. 

For our own studies today we use only ultrasound gel as contrast medium with a special rectal olive applicator, with which we first install 20-30 ml gel into the vagina and subsequently 200-300 ml into the rectum. This proved to be a fast, easy to perform... 

Certain abnormalities may not be visualised if the transducer pressure is too great. Fluid and effusions may be compressed, leading to underestimation of volume. When examining for a muscle hernia or tendon subluxation the pressure of the probe may prevent visualisation. Similarly, when assessing Doppler flow the vessels maybe inadvertently compressed. The use of copious ultrasound gel is the simplest way to avoid applying excessive pressure. 

Fig. 5 J Intracardiac Ultrasound for Vascular Access. Use of vascular ultrasound to gain access to the axillary vein can greatly facihtate left ventricular lead implantation by improving vascular access at the beginning of the procedure. Typical ultrasound probes have frequencies of 7.5 or 9 MHz (a). The higher frequency probes are better for access for more superficial vascular structures like those in the neck, whereas the lower frequency 7.5 MHz transducers permit acceptable imaging of the axillary, cephahc and portions of the subclavian veins. Ultrasound gel must be placed inside the plastic probe cover to gain acceptable images (b, Panel A). The plastic cover is secured with sterile rubber bands (b, Panel B). To differentiate to the axillary vein (V) from artery (A), gentle compression is applied to the vessels, causing the vein to collapse while the artery does not (c).

The only references of antimony available in the literature were the reactions in ethanolic solutions. Nowak et al. [133] have reported the sonochemical synthesis of SbSI gel by irradiating an ethanolic solution containing elemental antimony, sulfur and iodine for 2 h by the ultrasound of 35 kHz and 2 W/cm2 at 50°C. They also... 

Paulusse JMJ, van Beek DJM, Sijbesma RP. Reversible switching of the sol-gel transition with ultrasound in rhodium(I) and iridium(I) coordination networks. J Am Chem Soc 2007 129 2392-2397. 

It is important to note that buffers, accelerants and materials introduced to facilitate the work-up can be used simultaneously. Thus, it is common to use molecular sieves plus NaOAc,233 silica gel plus ultrasounds,2213 Celite plus NaOAc,234 AcOH plus molecular sieves,195b mont-morillonite K10 plus ultrasounds,198 molecular sieves plus Celite ,235 Celite plus AcOH236 or AcOH plus Celite plus molecular sieves.214c... 

To transfer ultrasound energy to the body, a coupling medium is required to overcome the high impedance of air. The many types of coupling medium currently available for ultrasound transmission can be broadly classified as oils, water oil emulsions, aqueous gels, and ointments. 

Properties of 2% Gel of Potato Starch Modified by Ultrasound, X-Rays, y-Rays, and Ultraviolet Radiation5... 

Samec3,5 has conducted comparative studies on the effects of various types of radiation on the properties of the dextrins produced and found notable differences. The origin of the starch seems to be a factor of minor importance, at least upon sonication with 995 kc/s and 120 W. Potato and arrowroot starch gave similar results.309 The action of ultrasound on starch gels produces complex changes.312,313 The mechanism of disintegration has been discussed by Sozaburo.314... 

Preparation of DMS0-Soluble Starch-g-PAN Samples and Water-Soluble Starch-g-Polyacrylamide. Five grams of starch- -PAN (prepared by either ceric- or cobalt-60 initiation) was dispersed in 333 g of DMSO, and the dispersion was heated for 2 hr at 115°C. The cooled dispersion was then treated with ultrasound for 10 min to mechanically rupture gel particles and to render the polymer soluble (Branson Sonifier, Model S 125 ... 

The benzannulation reaction is usually performed in ethereal solvents under mild conditions of gentle warming. Modifications of this general protocol involve the use of ultrasound or a dry-state adsorption (DSA) methodology, which involves the adsorption of the reactants onto silica gel, which may speed up the reaction and simplify the work-up procedure in some cases [58a, 58b]. Similarly, photoirradiation of the reaction mixture with light from a xenon lamp has been employed to produce the uncoordinated phenol derivatives without subsequent oxidative work-up [58c]. 

Two other important sol-gel parameters are temperature and solvent. Both hot and cold plates are commercially available and can be used to increase and decrease the reaction rates, respectively. Varying the temperature is most effective when it can alter the relative rates of competing reactions. Solvent can change the nature of an alkoxide through solvent exchange or affect the condensation reaction directly. It is also possible to prepare a gel without a solvent as long as another means, such as ultrasound irradiation [10] (see Section A.8.6), is used to homogenize an otherwise immiscible alkoxide/water mixture. 

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