Absence of biological activity

Conflicting results of various studies are attributed to type of preparation, route of administration, dosage, and presence or absence of biologically active compounds, among other factors. ... 

S-oxidation of sulfur-containing pesticides such as aldicarb, parathion, and malathion can be of importance in the absence of microbial activity (29). The products of chemical vs biological oxidation are generally identical (eq. 8). 

There is considerable experimental evidence indicating loss of biological activity of macromolecules such as globular proteins and enzymes at gas-Hquid [57], liquid-solid (Fig. 26) [107] and liquid-liquid [108] interfaces. The extent of inactivation has been shown to be strongly influenced by the prevailing flow field and by, many other factors including the presence and/or absence of additives and contaminants and the type of solid surfaces (Figs. 27 and 28) [107]. 

The absence of observed activity may represent either a true or false negative effect. If an assay is valid for the particular test article and fails to indicate activity, it is an appropriate indicator of future events (Green, 1997). However, if the assay is insensitive or incapable of response, the test represents a form of bias, albeit unconscious. Many biological products demonstrate a specificity of response that limits the utility of commonly employed safety studies. Specificity for many biologies arises from both their physicochemical properties and their similarity to endogenous substances that are regulated in a carefully controlled manner. To... 

As for the cultivation of other types of marine microorganisms, e.g., those with a specific potential for the production of biologically active metabolites, predominantly small-scale experiments (shake flasks) have been described. Alternatively, artificial seawater or 25 50 75 90% natural seawater has served as a basis for nutrient media. The concentrations of carbon and nitrogen sources reached up to 2 % (w/w) starch, glucose, molasses, glycerol, soybean oil, yeast extract, malt extract, beef extract, peptone, cornsteep liquor and NZ-amine. In the absence of artificial or natural seawater, high concentrations of... 

The design equations previously described are only valid when there are no factors which modify the kinetics of the immobilized biocatalyst (partition effects, heat and mass transfer effects and decay of biological activity) and the hydrodynamic characteristics of the reactor (back-mixing). Thus, the kinetic constants and used in those equations are intrinsic values obtained in the absence of those factors, being only dependent on the conformational and stereochemical effects inherent in the immobilization procedure used. 

However, the binding affinities of 197,206 and 207 [0.3%, 0.1% and <0.01%, respectively, relative to oestradiol (100%)] for the oestrogen specific acceptor protein of the rat uterus suggest that a steric or an electronic effect, rather than metabolic instability, is responsible for the absence of oestrogenic activity in these compounds. But a clear answer cannot be given because biological data of the direct 6,6-dimethyl-6-carba-analogues are not known so far. 

Biological treatment is the most common and most widespread technique used in effluent treatment, having been employed for over 150 years. There are two types of treatment, aerobic and anaerobic. The aerobic system needs air (oxygen) for the bacteria to perform the degradation process on the activated sludge, whereas anaerobic bacteria operate in the absence of air. Activated sludge usually removes only a moderate amount (10-20%) of the color. 

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