Mechanical pump approach

The mechanical pump approach employs miniature mechanical devices, such as implantable and portable infusion pumps and percutaneous infusion catheters, to deliver drugs into appro priate blood vessels or to a discrete site in the body. When compared with the... 

There is no one good way to prevent condensable vapors from affecting a mechanical pump. There are, however, two directions that one can take in dealing with the problem One is to limit them from getting to the pump, the other is to prevent them from affecting the pump once they are present. Neither is the best approach, and usually it takes combinations of the two to deal effectively with the problem. An alternative approach is to constantly change the pump oil. This solution however, is neither cost- nor time-effective. 

Later, other studies, typically in conjunction with much higher compression rates or increased force of compression (see Section 18.3.1.9), suggested that the rate in which compressions are performed maybe more important than the duty cycle (duration of the compression as Kttle as 20%). In addition, it became clear that only CPR performed mechanically (i.e., the Thumper ) is able to effectively perform short duty cycles at higher compression rates. Duty cycle alteration might be expected to effect output during CPR only from a thoracic pump approach [ 17]. 

This approach to fluidic propulsion does not rely on mechanical pumping rather, it is a surface-induced phenomenon. It requires an electrical insulator as the channel material and the ability of the surface to form a double layer. This tends to limit the appHca-bility to glass, surface modified silicon, and surface modifier polymer. EOF is best described by considering the situation occurring in a buffer-filled channel in a glass substrate. 

Equip a 500 ml. three-necked flask with a dropping funnel, a mechanical stirrer and a reflux condenser. Place a solution of 72 g. (65 ml.) of redistilled phenylhydrazine (Section IV,89) CAUTION poisonous) in 300 ml. of ether in the flask, stir vigorously, and add 33 g. (26 ml.) of A.R. carbon disulphide slowly during about 30 minutes. A precipitate is formed immediately upon the addition of the carbon disulphide, the mixture becomes warm and the temperature soon approaches the boiling point maintain the temperature just below the b.p. by cooling with ice water if necessary. When the addition is complete, stir for a further 30 minutes, then filter the precipitate at the pump, wash it with about 25 ml. of ether, and spread it upon filter paper for 20 minutes to permit of the evaporation of the ether. The yield of the salt (I) is 92 g. 

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