Freedom from contamination

These advantages include (a) Speed of assembly, (b) Well-fitting joints as these are made to accurate standards and joints of any given size are thus interchangeable, (c) Accurate alignment of assembly, for the use of incorrectly bored corks is obviated, d) Freedom from contamination of liquids by cork and rubber. 

Control fluid quality during use, involving checks on correct dilution and make-up, concentration and freedom from contamination in service, regular cleaning and fluid changing Provide and use appropriate personal protective equipment A high standard of personal hygiene... 

Inventory Reduce inventory of chemicals Continuous operation may be preferable to batch Low residence time contacting equipment may be better than cheaper alternatives etc. Monitor temperature, pressure flow, composition, freedom from contamination and other appropriate properties of all streams where relevant. Consider automatic control... 

The absence of corrosion, coupled with the fact that scale and other deposits appear to be dislocated by thermal cycling, result in a finish on tantalum heating surfaces that is as good as the original, even after 20 or 30 years in service, and also ensure that good heat-transfer properties are maintained throughout the life of the equipment. The use of tantalum for process equipment also ensures freedom from contaminations of the product. 

Monitor temperature, pressure flow, composition, freedom from contamination and other appropriate properties of all streams where relevant... 

Topical preparations, like all other dosage forms, must be formulated, manufactured, and packaged in a manner that assures that they meet general standards of bioavailability, physical (physical system) stability, chemical (ingredient) stability, freedom from contamination, and elegance. Like all other pharmaceuticals, these factors must remain essentially invariant over the stated shelf life of the product and they must be reproducible from batch to batch. 

In both research and practice, critical localised concentrations of metal contamination can be difficult to detect. Potassium hexacyanoferrate(II) (10.80) gives an intense deep blue coloration with iron(III), permitting extremely sensitive detection of tiny iron spots even by visual inspection. It is recommended as a quality control measure on batches of cotton destined for bleaching [237]. However, in view of the random distribution of metal traces, even the most sensitive test cannot guarantee freedom from contamination throughout a batch of goods to be bleached. 

The risk of viral contamination in plant-based medicinal products, and requirements for strategies to ensure that the product is consistently free of contaminating viruses, is discussed in detail in the EMEA document, while it is not addressed by the FDA. In addition to contamination by insect, bird and animal excreta or carcases, organic fertilizer, production personnel and equipment, the EMEA document lists plant virus infection as a source of contamination and claims that "... freedom from contamination with all types of viruses, irrespective of natural tropism, should be demonstrated. ... 

These workers conclude that the selective volatilisation technique is highly suitable for the determination of traces of molybdenum in synthetic (and most probably real) seawater samples. It has the advantages of freedom from contamination and loss during sample preparation and is faster, and cheaper, than procedures using separations. 

Rate of Solubility—The rath of solubility of small particles depends on a great number of variables. Eq (12-2) takes into account free surface energy (a) and particle surface (1 /d). These are purely surface considerations, and are scarcely complete in themselves. The shape of the surface and its physical state must also be specified, that is, its relative freedom from contamination which might influence the speed of reaction. The effect of packing density and the extent of agitation imparted to the particles are also important, particularly with regard to exposure of fresh surfaces and formation of possible gas pockets. The liquid and liquid-solid phases jointly are additional important considerations. The volume of the liquid, its temperature, and the amount of dissolved solid already in solution must enter into all calculations. Nor can we ignore the chemical nature of the substances involved in the... 

Neutron activation has been used to determine the concentrations of trace elements in polyethylene. A procedure has been optimized which involves three irradiations with a SICWFOKE nuclear reactor and four counts with a gamma-ray spectrometer. Phosphorus is determined with beta-ray spectrometry. The detection limits, most of which are below one ppm, have been determined for 42 elements. The merits of the method are discussed in terms of sensitivity, accuracy, ease of use, interferences, and freedom from contamination. 

The polarimeter is commonly used in organic and analytical chemistry as an aid in identification of optically active compounds (especially natural products) and in estimation of their purity and freedom from contamination by their optical enantiomers. The polarimeter has occasional application to chemical kinetics as a means of foUowing the course of a chemical reaction in which opticaUy active species are involved. Since the rotation a is a linear function of concentration, the polarimeter can be used in studying the acid-catalyzed hydrolysis of an optically active ester, acetal, glycocide, etc. 

Freedom from contamination is increasingly Important as solid state devices increase in complexity and decrease in size. Since corrosion control is a major problem in such devices, tests have been devised to assure the cleanliness level of manufactured parts. 

Measurement of color (ASTM D-156, ASTM D-848, ASTM D-1209, ASTM D-1555, ASTM D-5386, IP 17) provides a rapid method of checking the degree of freedom from contamination. Observation of the test for residue on evaporation (ASTM D-381, ASTM D-1353, IP 131) provides a further guard against adventitious contamination. 

Currently, most RTFs and mAbs are expressed in rodent, bacterial or yeast cell cultures (see Part IV, Chapter 13). A Master Cell Bank (MCB) should be estabbshed and tested for authenticity and freedom from contamination [5, 8, 11] (see also Part IV, Chapter 4). A Working Cell Bank (WCB) is extremely useful to extend the lifetime of the MCB. 

Several investigators have used neutron activation analysis (NAA) to determine the aluminium content of biological specimens both with and without some chemical processing. Instrumental neutron activation analysis involves the bombardment of a sample with neutrons and the measurement of the radioactivity induced by nuclear reactions. No chemical processing is required. Upon activation Al (100% isotopic abundance) forms the radioactive AI nuclide by a (n,y) reaction. There are a number of attractive features in this technique which include excellent sensitivity with relative independence from matrix effects and interferences. Also, there is relative freedom from contamination since the sample is analyzed directly with minimal handling. One major problem is the need to... 

Starting with the silicone elastomer hydrocephalus shunt in 1955, silicone elastomer has become widely used as a soft, flexible, elastomeric material of construction for artificial organs and implants for the human body. When prepared with controls to assure its duplication and freedom from contamination, specific formulations have excellent biocompatibility, biodurability, and a long history of clinical safety. Properties can be varied to meet the needs in many different implant applications. Silicone elastomer can be fabricated in a wide variety of forms and shapes by most all of the techniques used to fabricate thermosetting elastomers. Radiopacity can be increased by fillers such as barium sulfate or powdered metals. It can be sterilized by ethylene oxide, steam autoclave, dry heat, or radiation. Shelf-life at ambient conditions is indefinite. When implanted the host reaction is typically limited to encapsulation of... 

The measurements of performance capacities associated with human functions should conform to certain criteria. Details can be found in Brand and Crownshield [ 1981 ] and Chaffin [ 1982]. A general set of psychometric criteria is also discussed by Sanders and McCormick [1993]. It includes measurement accuracy, reliability, validity, sensitivity, and freedom from contamination. Meeting these criteria depends not only on the instruments used but also on the methods of analysis and the expertise of the analyst. It is almost impossible to satisfy these criteria perfectly, especially when the task is being performed in its natural environment (as opposed to a laboratory simulation). However, the analyst must always be aware of them and must be pragmatic in measuring task variables. Meister [1985] lists the following practical requirements for measurements (1) objective, (2) quantitative, (3) unobtrusive, (4) easy to collect, (5) requiring no special data-coUection techniques or instrumentation, and (6) of relatively low cost in terms of money and effort by the experimenter. However, these are not necessarily mutually exclusive. 

Surface resistivity is more a function of the nature of the plastic surface, its cleanliness, purity, and freedom from contamination. Surface resistivity is the ratio of the potential gradient parallel to the current along the surface to the current per unit width of surface. The most important factor about this measurement is the presence of moisture, which will significantly lower the surface resistance. 

Testing of powders and pressed parts to assure freedom from contamination (Ferroxyl test). 

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