Selectivity of response

Differentiation of vapor responses of the colloidal crystal film was accomplished with spectral measurements of the shape changes of the diffraction peak. Selectivity of response was obtained by applying multivariate data analysis to correlate these spectral changes to the effects of species of different chemical nature and to establish the identity and concentration of species. 

The analytical signal extraction block is based on determination of the maximum signal response and includes the following sections selection of response extremes, determination of the extreme parameters, elimination of the weak extremes and calculation of the analytical signal for pesticide quantification. The differences between the maxima in the biosensor response and baselines were used for the calculation of analytical signals, where the line drawn between two nearby minima within the limits of each injection was taken to be the base line. 

Factors may have associated values called levels of variations. Each state of a black box has a definite combination of factor levels. The more different states of the black box that exist, the more complex is the research subject. Formalization of preliminary information includes analysis of reference data, expert opinions and use of direct data, which enables correct selection of response, factors and null point or center of experiment. Factor limitations are also defined at this stage. If the research is linked with several following responses, then response limitations also have to be analyzed. The next phase refers to defining the research problem. When defining this problem one must keep in mind the research-subject model, and in a general case it is Eq. (2.1) that defines the link between the inlet and outlet of the black box. Defining the research problem is possible only now when its aim has been determined, the criteria established, the factors, limitations and null point defined. The problem is a simple one when only one response or optimization criterion is in... 

Ion mobility spectrometry (IMS) is an instrumental method where sample vapors are ionized and gaseous ions derived from a sample are characterized for speed of movement as a swarm in an electric field [1], The steps for both ion formation and ion characterization occur in most analytical mobility spectrometers at ambient pressure in a purified air atmosphere, and one attraction of this method is the simplicity of instrumentation without vacuum systems as found in mass spectrometers. Another attraction with this method is the chemical information gleaned from an IMS measurement including quantitative information, often with low limits of detection [2 1], and structural information or classification by chemical family [5,6], Much of the value with a mobility spectrometer is the selectivity of response that is associated with gas-phase chemical reactions in air at ambient pressure where substance can be preferentially ionized and detected while matrix interferences can be eliminated or suppressed. In 2004, over 20000 IMS-based analyzers such as those shown in Fig. 1 are placed at airports and other sensitive locations worldwide as commercially available instruments for the determination of explosives at trace concentration [7],... 

Statistical procedures for planning an experiment, i.e. collecting appropriate data which, after analysis by statistical methods, result in valid conclusions. The design includes the selection of experimental units, the specification of the experimental conditions, i.e. the specification of factors whose effect will be studied on the outcome of the experiment, the specification of the level of the factors involved and the combination of such factors, the selection of response to be measured, and the choice of statistical model to fit the data [Box et ai, 1978 Carlson, 1992]. 

Rathbone, D.L. Ge, Y., Selectivity of response in fluorescent polymers imprinted with M-benzylidene pyridine-2-carboxamidrazones, Anal. Chim. Acta. 2001, 435, 129-136... 

Selection of response actions that result in the recovery, or maintenance, of healthy local populations/communities of ecological receptors that are (or should be) present at the site furthermore, in support of proper risk management, risk assessors are advised to select assessment endpoints and measures (as defined in ERAGS) that are ecologically relevant to the site and include species that are exposed and sensitive to response to site contaminants, such as explosives. In addition, if individual threatened or endangered (T E) species or critical habitats for such species are present at a site, the Endangered Species Act may be declared an applicable or relevant and appropriate requirement (ARAR) within the ERA of the site. 

The term hyphenation was proposed by the late Thomas Hirschfeld [8.4] to emphasize a novel source of information obtained by a suitable combination of two mutually independent instrument responses with the purpose of enhancing tthe selectivity of response not attainable by a single instrument or even by the two individual instruments operated separately, but achieveable when these two instruments are appropriately linked— by a hyphen. Examples of well-known suitable combinations are GC-MS... 

The significance of the early membrane associated CL in monocytes is unknown, but appears to be specific, in that one of these unique peptides (f-Met-Phe) does cause CL and the other does not (f-Met-Ala). Support for specificity of this discriminatory response is provided by the data of Schiffman et al (1975), which point out that f-Met-Phe is more chemoattrac-tive for granulocytes than f-Met-Ala, This selectivity of response to dipeptides, the failure of zymosan to cause a burst of CL, and the dose response by latex particles, all suggest that early CL events are not spurious. On the other hand, their significance is currently only speculative. 

Selectivity of response to retinoids will be discussed, keeping in mind that certain isolated cell types have restricted metabolic activity. Particularly revealing are those studies that have employed a variety of retinoids. 

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