Other deconvolution methods

Several other deconvolution methods have been reported. Orthogonal libraries (168), subtractive deconvolution (169), omission libraries (170), bogus coin deconvolution (171), deletion synthesis deconvolution (172), and mutational SURF (Synthetic... 

The most stringent need for wavenumber axis calibration is in determinations based on band position. For this reason, qualitative analyses are likely to be affected by drifts or inaccuracy in the wavenumber axis [14]. Likewise, quantitative determinations based on band position, such as strain in diamond films [6], will be affected similarly. Other quantitative analyses may also be affected by band-position error. It is common to use the raw spectral intensities (intensity at every wavenumber) in a multivariate analysis. Although this approach can be very powerful, any unexpected shift in wavenumber calibration can cause severe error in the model. In essence, the spectral pattern to which the model has been trained has been shifted. The mathematics of the model are expecting a particular relationship of intensity between adjacent variables (wavenumbers) and cannot usually account for shifts [31], To some extent, multivariate models can be desensitized to inaccuracy and imprecision by assuring that the calibration samples also exhibit some of the same shifting features, but model sensitivity may suffer as a result. Although not in common use, other deconvolution methods have been introduced which may be applicable to removing shift effects of inaccurate wavenumber calibrations [37]. 

Finally, we suggest that a backlog of data on objects (spectra) of known properties be analyzed until the characteristics of the deconvolution method used are completely familiar. Only then should results yielded by unknown objects be judged. As in any other experimental work, the experiment should be repeated to verify reproducibility and develop confidence in the result. In this sense, the deconvolution process may be treated just like any piece of laboratory apparatus. Indeed, it takes on that identity when packaged in a laboratory microcomputer. 

Other approaches have been used for more complex models. These include curve stripping or the method of residuals,either manually or using a computer program such as CSTRIP and ESTRIF. These techniques can separate a multiexponential curve into its component parts for initial estimates. Other techniques include deconvolution methods specific to the one and two compartment pharmacokinetic models. The objective of the deconvolution method is to mathematically subtract the results obtained after IV administration from the oral or extravascular data. This results in information about the input or absorption process alone. More general methods have been presented by various researchers that do not rely on a particular compartmental model. ... 

Another recent study (Normand-Marleau, 2007) also included the lake Brome with several other lakes and rivers from Southern Quebec (123 samples). For the estimation of nitrate and total organic carbon with the above deconvolution method, the results were quite good with a correlation coefficient of 0.90 for both parameters. For nitrate, the concentration range was rather low (0 to 5 mg N/L) contrary to TOC range (0 to... 

The total concentration (C1 + C2) can be considered as a good estimation of global phenolic compounds concentration. According to the principle of the deconvolution method, the difference between the sample spectrum and the restituted one is defined by the quadratic error (see Chapter 3). If the quadratic error is higher than 5%, it means that other compounds are present and could interfere with the estimation of phenolic compound concentrations. In this case, no quantification is possible but a qualitative result can be displayed (presence of unknown compounds). 

The utility of HDC is somewhat limited by the relatively poor resolution and particle-size discrimination of the method, which restrict the precision of HDC in silica sol characterization. In principle, accurate particle-size distributions of silica sols also are possible with the HDC method. However, for such characterizations special software with corrections for the extensive band dispersion in HDC is required, along with a suitable band deconvolution method (28). Commercial HDC apparatus with this sophisticated software package apparently is no longer available. Standards are generally required, although quantitative retention relationships have been reported for capillary HDC systems in characterizing polymers (37). As with all of the other separation methods, careful selection of the mobile phase is required in HDC. Mobile phases generally are the same as those used for the FFF methods and SEC. 

The merit of deconvolution methods proposed in PK analysis only partially discussed by others - is appropriately judged by the extent to which data analysis errors discussed in this section are considered. 

An IR reference is available. If the absorption from an immediate-release (IR) formulation is a simple first-order process (i.e., described by a first-order absorption rate constant then it is possible by a relative deconvolution method or other means to obtain the shape of the absorption profile. ... 

There are several other nonlinear methods applied in different spectroscopies, the book edited by Jansson provides a broad review of nonlinear deconvolution. 

Correlations can be made between integrated infrared band intensity values (calculated using spectral deconvolution with baseline subtraction) and results from other characterization methods. The content of=Si-0-Ti= bonds in ST samples (Figure 2.10a, 960/800 cm- band area ratio) is found from integrated absorbance values from transmission spectra of thin films at room temperature, since surface adsorbed water does not interfere with these measurements. Additionally, diffuse reflectance spectra recorded at 573 K (Figure 2.9a, 960/1860 cm" band area ratio) give a similar... 

---