Biological counting

A typical microbiological analysis in a troubled carbon-steel service water system is given in Table 6.2. Table 6.3 shows a similar analysis for a cupronickel utility main condenser that showed no significant corrosion associated with sulfate reducers. When biological counts of sulfate reducers in solid materials scraped from corroded surfaces are more than about 10, significant attack is possible. Counts above 10 are common only in severely attacked systems. 

Clearly, the next step is the handling of a molecule as a real object with a spatial extension in 3D space. Quite often this is also a mandatory step, because in most cases the 3D structure of a molecule is closely related to a large variety of physical, chemical, and biological properties. In addition, the fundamental importance of an unambiguous definition of stereochemistry becomes obvious, if the 3D structure of a molecule needs to be derived from its chemical graph. The moleofles of stereoisomeric compounds differ in their spatial features and often exhibit quite different properties. Therefore, stereochemical information should always be taken into ac-count if chiral atom centers are present in a chemical structure. 

Y. Kobayashi and D. V. Maudsley, Biological Applications ofEiquid Scintillation Counting, Academic Press, Inc., New York, 1974. 

In order to discuss the biological mechanisms involved in the aetiology of genital tract malformations, testicular cancer and lowered sperm counts, some knowledge of the processes involved in the differentiation and development of the male reproductive tract and determination of normal testicular function is required. An early embryo has the potential to develop either a male or a female... 

Kucera J, Vobecky M, Soukal L, Zakoucky D, and Venos D (1997) Low level determination of thallium in biological and environmental reference materials by RNAA using several counting methods. J Radioanal Nud Chem 217 131-137. 

Classification methods for leukemia have evolved from simple schemes that were largely phenotypic and considered only age, gender, WBC count, and blast morphology to now-complex methods that include biologic features such as cell-surface receptor features and cytogenetics. 

Like age, the WBC count at presentation is a reliable indicator of CR rate and outcome. WBC count is indicative of tumor burden, although the underlying biologic mechanisms that account for the unfavorable outcomes associated with an elevated WBC count are unclear. Patients with WBC counts of less than 50 X 103/jliL (50 x 109/L) are considered standard risk, and a higher WBC count at presentation is associated with higher risk of treatment failure (Table 92-6). 

Guilmette RA, Bay AS. 1981. Radio assays of americium or curium in biological material by isoctyl acid phosphate solvent extraction and a liquid scintillation counting. Anal Chem 53 2351-2354. 

The automated EXAMS model consists of a set of FORTRAN programs which calculates the fate, exposure and dissipation of the chemical from input environmental data such as 1) Global parameters (rainfall, irradiance, latitude), 2) Biological parameters (biomass, bacterial counts, chlorophyll), 3) Depths and in-lows, 4) Sediment characteristics, 5) Wind, 6) Evaporation, 7) Aeration, 8) Advective and turbulent interconnections, 9) Water flow, 10) Sediment flow, 11) pH and pOH, and 12) Temperature. Also characteristics of the chemical are taken into account such as hydrolysis photolysis, oxidation, biolysis, and volatility. 

The lifetime resolution is the smallest variation in lifetime that can be detected. If external noise sources are ignored, the lifetime resolution depends essentially on the photon-economy of the system. For instance, if a 2 ns lifetime is measured with a 4 gate TG single-photon counting FLIM (F = 1.3) and 1000 photons, variations of about 80 ps can be resolved. However, for reasons discussed earlier, in biological samples these values could be higher. 

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