Standard reference weight

VD Relative vapor density of the gaseous agent as compared to air. Unless otherwise indicated, these values are calculated based on the standard reference weight of air (i.e., 29). 

The approach adopted by CSIRO (2007) to calculate the protein requirement for gain is similar to that described for energy (see p. 355), with the NPg being calculated from the liveweight of the animal relative to its standard reference weight (SRAV) and its rate of gain as ... 

TABLE 8.17 Standard Reference Values pH for the Measurement of Acidity in 50 Weight Percent Methanol-Water... 

The reliability of the results depends in large measure on how well deviations from the (ideal) linear relationship between log / and dry weight per unit area can be eliminated or allowed for. As is well known, this can be accomplished by the comparative method (3.10), provided that standard (reference system) and unknown, identical in mass, shape, and elementary composition, are exposed to the same x-ray beam. In the cytological investigations, these conditions are difficult to meet, not only because the samples are complex in composition, but also because they are very small, as is clear from the units employed (micromicrograms per square micron or 10 12 gram per 10 8 sq cm). 

In order to measure the exact amount of a specific protein (analyte) by IHC signal intensity, a critical requirement is the availability of a standard reference material (present in a known amount by weight) that can be used to calibrate the assay (IHC stain). It is then possible to determine the amount of test analyte (protein) by a translation process from the intensity of IHC signals. In this respect it is helpful to consider the IHC stain as a tissue based ELISA assay (Enzyme Linked ImmunoSorbent Assay), noting that ELISA is used in the clinical laboratory as a standard quantitative method for measuring protein by weight in fluids, by reference to a calibrating reference standard. 

A standard reference material with an accepted analyte content of 5.85 ppm was used to compare the performance of two alternative methods of analysis. Solutions were prepared using a range of sample weights. Each solution was analysed by the two methods. Use the results obtained to assess any determinate errors exhibited by the methods. 

Determined by GPC with polymethyl methacrylate (PMMA) as the reference standard. "Molecular weight distributions. 

FIGURE 3.17 Three-dimensional plot of scattering intensity as a function of scattering angle and elution volume for a broad molecular weight distribution (MWD) polystyrene (PS) (NITS standard reference 706). (Courtesy of Wyatt Technology Corporation, Santa Barbara, CA 93117 wyatt wyatt.com. With permission.)... 

Wise, S. A., A. Deissler, and L. C. Sander, Liquid Chromatographic Determination of Polycyclic Aromatic Hydrocarbon Isomers of Molecular Weight 278 and 302 in Environmental Standard Reference Materials, Polycyclic Aromat. Compd., 3, 169-184(1993). 

Because sample homogeneity is particularly important for a Standard Reference Material, it was carefully assessed for both polystyrenes using solution viscosity, a measure of molecular weight, as an index. There is essentially no variation with location within the lot, or from pellet to pellet, within the limits of error of the viscosity measurements. Viscosity measurements may be made with a standard deviation of a single determination of about 0.3%. 

Standard Reference Material 705, Polystyrene (Narrow Molecular-Weight Distribution)... 

The values of AHf° and AGf° given in the tables represent the change in the appropriate thermodynamic quantity when one gram formula weight of the substance in its standard state is formed, isothermally at the indicated temperature, from the elements, each in its appropriate standard reference state. The standard reference state at 25 °C for each element has been chosen to be the standard state that is thermodynamically stable at 25 °C and 1 atm pressure. The standard reference states are indicated in the tables by the fact that the values of AHf° and AGf° are exactly zero. 

Analytical balances must be regularly checked against reference weights provided by the US National Institute of Technology and Standards (the old National Bureau of Standards). Other countries have similar calibration services. Some balances have an internal calibration standard, which periodically resets crucial software parameters that control the front-panel display. 

Procedure Transfer 10.0 mL of Solution II into a 19- x 150-mm cuvette, and continue as directed under Standard Reference Curve, beginning with add 4.0 mL of a freshly prepared 1 20 sodium metavanadate solution.. .. From the reference curve, determine the weight, in milligrams, of tartaric acid in the final dilution, multiply this by 20, and divide the result by the weight of the original sample to obtain the percentage of tartaric acid. 

---