Methodology of Measurement

An absolute method is based on stoichiometric chemical reactions such as titrations (acid/base, redox, precipitation and chelometry, coulometry, voltammetry). Methods that are accepted or developed by official laboratories are usually accurate, precise and used by other laboratories throughout the world. A significant number of methods for atomic spectroscopy also fall into these categories and are readily available from the appropriate literature. Developed and accepted methods give confidence in reporting of results because all the teething problems and pitfalls associated with that method would have been observed and noted by other users. Standards must be as close as possible to the 

---

Pohl, E., F. Steinhausler, W. Hofmann, and J. Pohl-Ruling, Methodology of Measurements and Statistical Evaluation of Radiation Burden to Various Population Groups From All Internal and External Natural Sources, in Proceedings of Biological and Environmental Effects of Low-Level Radiation, International Atomic Energy Agency), Vol.II, pp. 305-315, Vienna, Austria (1976). 

Voltammetry The techniques and methodology of measuring current as a function of applied potential. 

Principles and Methodologies of Measuring Microbial Activity and Biomass in Soil... 

The basic methodologies of measuring JH titer and rates of biosynthesis will be mentioned here only briefly. JH titer is determined by either radioimmunoassay (3) or preferably by gas chromatography coupled with mass-spectrometry (4-6). Alternatively, JH biosynthesis can be determined with excised CA in vitro by the radiochemical (RCA) method (2). JH values obtained by titering reflect the equilibrium of rate of JH synthesis, its degradation and clearance from the hemolymph, its tissue uptake and excretion. The rate of de novo synthesis, as measured by the RCA method, is argued to correlate well with JH hemolymph titer (8.9). As we shall later show, the correlation of in vitro synthesis and ija vivo titers is not always maintained in L. migratoria under all experimental situations. 

In the paper, the methodology of measuring G c by using DCB specimens in the presence of large-scale bridging is adapted for investigating the delamination in 3D woven composites. 

It has to be remembered that the results of in vitro and ex vivo studies on the effect of n-3 LC-PUFA on LDL oxidation are equivocal. Many studies showed either no LDL oxidation under fish oil (27-32), or even a decrease in the rate and the extent of oxidation (33,34). These seemingly contradictory findings may be related to the methodology of measuring LDL oxidation, as well as to the actual variable chosen to evaluate LDL susceptibility. To what extent oxidative susceptibility of LDL measured ex vivo reflects oxidative susceptibility in vivo is unknown. 

In the previous sections the enzyme concentration was held constant for purposes of discussion. It is obvious from equation 9 that the velocity of an enzyme reaction is proportional to the amount of enzyme present. Van Slyke has very well presented the methodology of measuring the concentration of hydrolytic enzymes. For studies on purification it is often the case that the initial velocity constants, proportional to the enzyme concentration, can be used. In situations where the substrate concentration is kept low or Km is large, first-order kinetics predominate to the extent that Ki (equation 2) is proportional to the enzyme concentration. In cases where the substrate concentration can be raised high enough to saturate the enzyme, that is, where Km is small, the initial velocity of the reaction may be directly proportional to the enzyme concentration. ... 

---