The Free–Wilson paradigm <i>redux</i>: Significance of the Free–Wilson coefficients, insignificance of coefficient ‘uncertainities’ and statistical sins

Duewer, David L.

doi:10.1002/cem.1180040405

Cited by 17 publications

(3 citation statements)

References 10 publications

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“…Any given value of the log-transform data is easily inverse-transformed back to the original measurements, y = 10 y‘ . However, an additively symmetrical interval for the log-transformed data, y ‘ ± ku ‘ = y ‘ − ku ‘ ≤ y ‘ ≤ y ‘ + ku ‘, becomes multiplicatively symmetrical when inverse-transformed back to the more familiar measurement domain, y × u k = ( y / u k ) ≤ y ≤ y × u k . The notation “×” is employed as the multiplicative analogue of “±”.…”

Section: Methodsmentioning

confidence: 99%

NIST Mixed Stain Study 3: DNA Quantitation Accuracy and Its Influence on Short Tandem Repeat Multiplex Signal Intensity

et al. 2003

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The Mixed Stain Study 3 (MSS3) interlaboratory challenge exercise evaluated the 2001 performance of STR multiplex DNA typing systems using a set of seven DNA extracts of designed concentration and composition. This initial report focuses on the linkages connecting the measurement of the concentration of DNA ([DNA]) to the observed STR multiplex signal intensities. There is a causal relationship between [DNA] measurement accuracy and the efficiency of STR multiplex analysis. There are no intrinsic measurement performance differences among the [DNA] measurement technologies reported. However, there are large differences in the efficiencies of amplification, separation, and detection among participants using the same nominal measurement systems.

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Section: Methodsmentioning

confidence: 99%

NIST Mixed Stain Study 3: DNA Quantitation Accuracy and Its Influence on Short Tandem Repeat Multiplex Signal Intensity

et al. 2003

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“…My introduction to the use of quantitative structure–activity and structure–property relationships (QSARs and QSPRs) in herbicide discovery took place a little over 25 years ago when I joined what was then the Monsanto Agricultural Company. While there, I had the privilege of working with several distinguished scientists, among them Dave Duewer1, 2 and Larry Brannigan 3–5. My involvement with the pyrazole phenyl ether synthesis program at Monsanto6, 7 also gave me the opportunity to collaborate with Stephen Duke's group at the US Department of Agriculture in their ground‐breaking work on protoporphyrinogen IX oxidase (PPO) as the target of diphenyl ether herbicides 8–10…”

Section: Introductionmentioning

confidence: 99%

A perspective on the role of quantitative structure–activity and structure–property relationships in herbicide discovery

Clark

2012

Pest Management Science

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“…some special features [3,4] requiring certain precautions in the application of direct methods of regression analysis.…”

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confidence: 99%

QSAR analysis of clophelin-like imidazolines on the basis of a listing description of molecular structure

Vityuk

1997

Pharm Chem J

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Choice of the type of description for the arialysis of quantitative structure-activity relationships (QSAR) of a given chemical structure is determined by the character of each particular problem and the time and effort required to obtain experimental and calculated data representing the structure. For the QSAR analysis of a group of compounds characterized by the same type of activity, whose structures comprise a main fragment (nucleus) and variable substituents, the minimum expenditures are provided by reducing the description to indicating the type of substituent and its position in a given molecule. In this approach, the structural signs of the molecule are essentially measured against a dichotomic (binary) scale refleeting the presence or absence of a specified quality in the given object [1].Such a binary scale for measuring the structural signs is used, in particular, in the Free-Wilson model [2], whose predicting ability is based on the assumption that the biological activity (A or log A ) of a molecule is determined by the sum of contributions due to the activities of substituents, that is tTl A=a0+ ~-~ aj X:-.( 1) j=lHere aj is the contribution ofthejth substituent (j = ~ ) to the total activity A, and X] is a binary variable equal to unity or zero, depending on whether thejth substituent is present or absent in the structure, respectively. The regression coefficients a are obtained by solving a system of n equations of type (1) for a sample set of n molecules (n >> m ). The Free -Wilson method is sill an attractive tool for the QSAR analysis [3 -6] despite a number of disadvantages inherent in this approach. For example, one essential feature of the method is the requirement for availability of considerable statistical material (the number of molecules n constituting the teaching set must significantly exceed m, the number of substructures). Moreover, the structure of the covariation matrix employed in the Free-Wilson method also exhibits 1 Odessa State Marine University, Odessa, Ukraine. 205some special features [3,4] requiring certain precautions in the application of direct methods of regression analysis.As is known, the use of regression techniques imposes certain limitations on the initial numerical data file [3]. Therefore, it is an interesting task to implement the heuristic Free -Wilson paradigm on the basis of an alternative, nonregressive approach capable of processing multidimensional bodies of experimental data for relatively small sample sets. For example, we employed the method oft-rend-vector [5] for determining the contributions of various substructures to the activity of a molecule. In this work, we suggest to employ the method ofbaricentric coordinates (BC) in the description of a multidimensional space of characteristics of the molecular substructures [6,7].In the BC system, each point in the m-dimensional space is represented as the center of gravity of an m-gon whosejth vertex has a mass proportional to Qy, the contribution of the correspondingjth structural sign Sj to the total ac...

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The Free–Wilson paradigm redux: Significance of the Free–Wilson coefficients, insignificance of coefficient ‘uncertainities’ and statistical sins

Cited by 17 publications

References 10 publications

NIST Mixed Stain Study 3: DNA Quantitation Accuracy and Its Influence on Short Tandem Repeat Multiplex Signal Intensity

NIST Mixed Stain Study 3: DNA Quantitation Accuracy and Its Influence on Short Tandem Repeat Multiplex Signal Intensity

A perspective on the role of quantitative structure–activity and structure–property relationships in herbicide discovery

QSAR analysis of clophelin-like imidazolines on the basis of a listing description of molecular structure

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