Reference standards types

Rhinitis is characterized by nasal stuffiness with partial or full obstmction, and itching of the nose, eyes, palate, or pharynx, sneezing, and rhinorrhoea. If left untreated it can lead to more serious respiratory diseases such as sinusitis or asthma. Although several types of dmgs are available for treatment, nasal spray topical corticosteroids are widely regarded as the reference standard in rhinitis therapy (250). 

Radiographic Examination. Main load carrying components of the equipment shall be examined by means of gamma rays or x-rays. The procedure used shall be in accordance with applicable ASTM standards. Types and degrees of discontinuities considered shall be compared to the reference radiographs of ASTM as applicable. The extent of examination and the basis for acceptance shall be agreed upon by the manufacturer and purchaser. 

Tabic 1.1. Amino acids per thousand residues for standard type 1 collagen and 15 human bone collagen samples from St. Thomas Church cemetery. Samples are identified by burial numlter (Bx) followed by age midpoint for subadults and age range for adults in parentheses. For example, B17(0) refers to burial 17 who was aged as a newborn. 

Optical microscope asbestos reference standards for use in identifying and quantifying asbestos types are available both from NIST and the Institute of Occupational Medicine flOM) in Edinburgh, Scotland. The lOM materials consists of various asbestos materials actinolite, amosite, anthophyUite, chrysotile (both from Cassiar, Canada and Zimbabwe), crocidolite and tremoUte. 

Fig. 3.16 Schematic drawing of the MIMOS II Mossbauer spectrometer. The position of the loudspeaker type velocity transducer to which both the reference and main Co/Rh sources are attached is shown. The room temperature transmission spectrum for a prototype internal reference standard shows the peaks corresponding to hematite (a-Fe203), a-Fe, and magnetite (Fe304). The internal reference standards for MIMOS II flight units are hematite, magnetite, and metallic iron. The backscatter spectrum for magnetite (from the external CCT (Compositional Calibration Target) on the rover) is also shown...

RBE is used to denote the experimentally determined ratio of the absorbed dose from one radiation type to the absorbed dose of a reference radiation required to produce an identical biologic effect under the same conditions. Gamma rays from cobalt-60 and 200-250 keV x-rays have been used as reference standards. The term RBE has been widely used in experimental radiobiology, and the term quality factor used in calculations of dose equivalents for radiation safety purposes (ICRP 1977 NCRP 1971 UNSCEAR 1982). RBE applies only to a specific biological end point, in a specific exposure, under specific conditions to a specific species. There are no generally accepted values of RBE. 

Schirmer has succinctly summarized the strengths and limitations of phase solubility analysis [40]. The principal advantages are that (1) a reference standard known purity is not required, (2) the number and types of impurities in the sample need not be known, (3) all required solubility information is obtained from the analysis, (4) the technique can be applied to the analysis of any solute that can be dissolved in some solvent, (5) the deduced results are both precise and... 

The Cl shift of Mossbauer spectra provides a measure of the total electron density in the nucleus of an atom, i/r(o), relative to some reference standard. For Fe, 8 is quite sensitive to valence, coordination number, or number and type of bonds to its ligands. Unlike chemical shifts in NMR spectra which are frequently dominated by the spin... 

As it is imperative that the plant-derived hiopharmaceutical product must be obtained repeatedly and on a consistent basis, a master cell culture bank, seed bank for transgenic plants, or virus seed stock for transient expression systems must be constantly maintained. Storage conditions must therefore he optimized to prevent contamination and ensure viability. Both transgene stability (e.g., reversion to wild type or sequence drift of plant virus expression vectors) and protein expression levels must be monitored in a representative plant of a given bank or stock to minimize any possible variation in expression levels that may affect safety and consistency of the hnal product. A program that monitors lot-to-lot consistency of the hiochemical and biological properties by comparing the product with appropriate in-house reference standards could he implemented as a fundamental component of product development. 

Two sets of typical operating conditions are used for the simulations presented. These are shown in Table IV and will be referred to as standard type I or II conditions. Type I corresponds to operation at moderate to high temperatures, pressures, and flow rates with relatively low inlet CO and H2 concentrations and small amounts of inlet CH4, C02, and HzO either from recycle or from the upstream process. Type II is based on conditions for the industrial use of methanation in synthetic natural gas production. Note that the inlet methane concentration is much higher than in type I. 

External Standard. In this approach, related substance levels are determined by calculation using a standard curve. The concentration of related substance is determined by the response (i.e., peak area of individual related substance) and the calibration curve. A reference standard of the drug substance is typically used in the calibration. Therefore, a response factor correction may be required if the response of related substance is very different from that of the drug substance. A single-point standard curve (Figure 3.4) is appropriate when there is no significant v-intercept. Otherwise, a multipoint calibration curve (Figure 3.5) has to be used. Different types of calibration are discussed in Section 3.2.3. 

The purity of the reference standard used to prepare spiked samples can affect the study data. For this reason, an analytical reference standard of known identity and purity should be used to prepare solutions of known concentrations. If possible, the reference standard should be identical to the analyte. When this is not possible, an established chemical form (free base or acid, salt, or ester) of known purity can be used. Three types of reference standards are generally used ... 

Figure 16.24—Instrument for isotope ratio measurements. The high sensitivity required by these types of analyses is achieved by placing several Faraday-type detectors after the magnet, each recording the current at a single mass. A reference standard is injected with the sample.

These measure the change in thermal conductivity of a gas due to variations in pressure—usually in the range 0.75 torr (100 N/m2) to 7.5 x 10"4 torr (0.1 N/m2). At low pressures the relation between pressure and thermal conductivity of a gas is linear and can be predicted from the kinetic theory of gases. A coiled wire filament is heated by a current and forms one arm of a Wheatstone bridge network (Fig. 6.21). Any increase in vacuum will reduce the conduction of heat away from the filament and thus the temperature of the filament will rise so altering its electrical resistance. Temperature variations in the filament are monitored by means of a thermocouple placed at the centre of the coil. A similar filament which is maintained at standard conditions is inserted in another arm of the bridge as a reference. This type of sensor is often termed a Pirani gauge. 

This is a case for which only stabilization is of interest. It has not been treated explicitly as an excitation reaction. Its rate has been measured directly103-105 at low temperatures (300-450 °C) as have those for several other radical combinations. Without doubt, the combination of methyl radicals is the most important reaction of this type for chemical kinetics. It serves as a reference standard for the measurement of rates of many hydrogen abstraction reactions, but very little is known about the temperature dependence of its rate coefficient. 

The assay of stressed samples will usually require the use of some type of external standard. The external standard could be an established reference standard, however, the preferred method is to use the same material/lot as is being stressed. This is easily accomplished by weighing additional samples (that will not be stressed) for use as standards at the same time as the stress test samples are weighed. The standards should then be stored under conditions that will assure that no degradation will occur (e.g., freezer). At the time of analysis, the stressed samples are simply assayed vs. the freshly prepared unstressed standards and the results calculated as percent initial. 

Thin layer chromatography is yet another means for determining identity of moxalactam materials. The mobility of the moxalactam sample must be identical to the mobility of the moxalactam reference standard which is run on the same TLC plate. The developing solvent for TLC consists of 42 parts ethyl acetate 14 parts glacial acetic acid 14 parts acetonitrile and 18 parts water. A silica gel type F plate is used and is viewed under short wavelength UV light to detect the position of the components on the developed plate. 

This type of test is called parallel-line assay and is based on the comparison of a sample response with that of a reference standard (Finney, 1978). In general, it determines the response - at least by duplicates - of a series of dilutions of each preparation (sample and standard) while plotting the means of their corresponding doses on a logarithmic scale. As this test requires analysis of a linear portion of the curves, at least three points of each curve belonging to such a portion should be selected. The more selected points, the better the comparison. 

The method requires the use of a reference standard sample in order to set the sensitivity level before an unknown sample is tested for discontinuities. The type of reference discontinuities used in a particular application has been specified by the American Society for Testing Materials and the American Petroleum Institute. Some reference standards are depicted in Figure 2.10. Some of the discontinuities detected are seams, laps, cracks, slivers, scabs, pits, slugs, open welds, miswelds, improperly or misaligned welds, black or gray oxide weld penetrators, pinholes, hook cracks and surface cracks. 

By specifically and selectively reconstructing the total ion peak observed after a loop flow injection to display only the m/z values of interest, the area count for that ion can be extracted from the composite total ion peak. The measured area count can then be used to estimate the quantity of specific alkaloid by comparison to a calibration curve. Thus, component compounds in a mixture are separated by mass, as opposed to chromatography, for quantitation. To normalize the variability of the API response, an internal reference standard is added to the sample prior to loop injection. Alkaloids for which standards are not available are reported as equivalents of a closely related and available standard used to generate the calibration curve, for example, deltaline and methyllycaconitine have been used as calibration standards to represent the non-MSAL and MSAL types of alkaloids, respectively, in the plant material. Calibration curves for these two compounds were linear (r > 0.990) and there appears to be no selective suppression of lower-level alkaloids (figure 13.21). Multiple analyses of Delphinium barbeyi samples returned a level ofprecision that was less than 10 % (relative standard deviation) for all components [56]. 

Inhomogeneous structural disturbances, of course, can only be understood by comparison to a reference standard, or ideal stmcture. The types of disturbances discussed will... 

For both these reference electrode types, the potentials are accurately known relative to the standard hydrogen electrode (SHE) for which the chemical reaction is (5). The SHE is based upon a high surface area platinum black-coated electrode in contact with hydrogen gas (one atmosphere... 

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