Multivariate screening

Multivariate screening has allowed identification of catalytic conditions that most likely would not have been uncovered by traditional searching [48]. Rapid, multivariable, automated screening will accelerate the development and optimization of catalytic reactions [49]. 

Fordedal H, Midttun O, Sjoblom J, Kvalheim OM, Schildberg Y, Voile JL. A multivariate screening analysis of W/O emulsions in high external electric fields as studied by means of dielectric time domain spectroscopy. II. Model emulsions stabilized by interfacially active fractions from crude oils. J. Colloid Interface Sci 1996 182 117-125. 

Multivariate screening tools are needed in order to model the underlying latent functional factors which determine what happens in the examined systems, and are the basis for an exploratory, inductive data strategy. 

A. J. Charlton, W. H. Farrington, P. Brereton 2002, (Application of 1H NMR and multivariate statistics for screening complex mixtures quality control and authenticity of instant coffee), J. Agric. Food Chem. 50, 3098-3103. 

Wavelength database libraries of >32000 analytical lines can be used for fast screening of the echellogram. Such databases allow the analyst to choose the best line(s) for minimum interferences, maximum sensitivity and best dynamic range. Further extension of the wavelength range (from 120 to 785 nm) is desirable for alkali metals, Cl, Br, Ga, Ge, In, B, Bi, Pb and Sn, and would allow measurement of several emission lines in a multivariate approach to spectral interpretation [185]. 

Wu et al. [46] used the approach of an artificial neural network and applied it to drug release from osmotic pump tablets based on several coating parameters. Gabrielsson et al. [47] applied several different multivariate methods for both screening and optimization applied to the general topic of tablet formulation they included principal component analysis and... 

Goodacre, R. Trew, S. Wrigley-Jones, C. Neal, M. J. Maddock, J. Ottley, T. W. Porter, N. Kell, D. B. Rapid screening for metabolite overproduction in fermentor broths using pyrolysis mass spectrometry with multivariate calibration and artificial neural networks. Biotechnol. Bioengin. 1994, 44,1205-1216. 

The traditional acute, subchronic, and chronic toxicity studies performed in rodents and other species also can be considered to constitute multiple endpoint screens. Although the numerically measured continuous variables (body weight, food consumption, hematology values) generally can be statistically evaluated individually by traditional means, the same concerns of loss of information present in the interrelationship of such variables apply. Generally, traditional multivariate methods are not available, efficient, sensitive, or practical (Young, 1985). 

Andersson M. Ringberg A. Gustafsson C. Multivariate methods in tablet formulation suitable for early drug development Predictive models from a screening design of several linked responses. Chemometrics and Intelligent Laboratory Systems, 2007, 87 (1), 151-156. 

During a screening campaign some plates and even entire batches can fail due to various reasons. To control the quality of plates, during a screen, we use the Z-primes and the Multivariate Z-primes nodes we have developed. Plates failing to fulfill a minimal criterion such as a Z-prime factor above 0.3 are eliminated from further analysis and scheduled for rescreening. A further useful node to verify the quality of plates is the CV node that calculates coefficients of variance for selected parameters. 

Conte, P. (2008). IH NMR spectroscopy with multivariate statistical analysis as a tool for a rapid screening of the molecular changes occurring during micro-oxygenation of an Italian red wine. Open Magn. Reson. J. 1, 77-80. 

Jacobsson, M., Liden, P., Stjernschantz, E., Bostrom, H., Norinder, U. Improving Structure-based Virtual Screening by Multivariate Analysis of Scoring Data./. Med. Chem. 2003, 46, 5781-5789. 

If values for the impact of emissions from different monitoring raster screens are submitted, or if differently loaded areas can be assumed from a knowledge of the emission structure and the specific territorial situation, it is obvious that differences in the impact of emissions can be classified in a multivariate maimer. 

The multivariate autocorrelation function of the measured values compared with the highest randomly possible correlation value shows significant correlation up to Lag 7. So, the range of multivariate correlation is more extended than that of univariate correlation (see Section 9.1.3.3.1). This fact must be understood because the computation of the MACF includes the whole data matrix with all interactions between the measured parameters. For characterization of the multivariate heavy metal load of the test area only 14 samples in the screen are necessary. 

M Jacobsson, P Liden, E Stjemschantz, H Bostrom, U Norinder (2003) Improving Structure-Based Virtual Screening by Multivariate Analysis of Scoring Data, J Med Chem 46(26) 5781—5789... 

An awareness of the influences of various factors on the biodiesel will give a clear picture of the possible independent variables which can be manipulated to improve or optimize production (the dependent variables). Among dozens of possible candidates, use of some is limited by consumer habit or by the unavailability of the required tool, while others may give a higher priority to those variables that are convenient to adjust, and leave those that demand more time and effort for later study. After screening, the remaining few may thus form the basis for a focused study. However, optimization is not easy even with only two or three variables. RSM has been developed particularly for the optimization of sophisticated multivariable systems where the quantitative relationship between key variables is not always clear, as is the case with a complex operation such as transesterification. RSM allows simultaneous consideration of more than one variable at different levels, and of the corresponding interactions between these variables, on the basis of a relatively small number of experiments. 

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