			Home About us Contact

Property Space (property + space)

Distribution by Scientific Domains

Chemistry	71%

Selected Abstracts

Multi-Criteria Material Selection of Monolithic and Multi-Materials in Engineering Design

ADVANCED ENGINEERING MATERIALS, Issue 1-2 2006
P. Sirisalee
Multi-materials are combinations of monolithic materials in a chosen configuration and scale. They can help populate the material property space and fill areas monolithic materials cannot reach. This paper presents a novel approach to compare the performance of monolithic materials and multi-materials in multi-criteria design problems, with the results being visualised through exchange constant charts. In this paper, a particular type of multi-materials, sandwich panels, is selected to demonstrate the approach. [source]

Controlling coverage of D-optimal onion designs and selections

JOURNAL OF CHEMOMETRICS, Issue 12 2004
Ing-Marie Olsson
Abstract Statistical molecular design (SMD) is a powerful approach for selection of compound sets in medicinal chemistry and quantitative structure,activity relationships (QSARs) as well as other areas. Two techniques often used in SMD are space-filling and D-optimal designs. Both on occasions lead to unwanted redundancy and replication. To remedy such shortcomings, a generalization of D-optimal selection was recently developed. This new method divides the compound candidate set into a number of subsets (,layers' or ,shells'), and a D-optimal selection is made from each layer. This improves the possibility to select representative molecular structures throughout any property space independently of requested sample size. This is important in complex situations where any given model is unlikely to be valid over the whole investigated domain of experimental conditions. The number of selected molecules can be controlled by varying the number of subsets or by altering the complexity of the model equation in each layer and/or the dependency of previous layers. The new method, called D-optimal onion design (DOOD), will allow the user to choose the model equation complexity independently of sample size while still avoiding unwarranted redundancy. The focus of the present work is algorithmic improvements of DOOD in comparison with classical D-optimal design. As illustrations, extended DOODs have been generated for two applications by in-house programming, including some modifications of the D-optimal algorithm. The performances of the investigated approaches are expected to differ depending on the number of principal properties of the compounds in the design, sample sizes and the investigated model, i.e. the aim of the design. QSAR models have been generated from the selected compound sets, and root mean squared error of prediction (RMSEP) values have been used as measures of performance of the different designs. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Musings on ADME Predictions and Structure,Activity Relations

CHEMISTRY & BIODIVERSITY, Issue 11 2005
Bernard Testa
The first part of the paper examines Structure,Activity Relations (SARs) and their components from a very general point of view. The various types of interpretation emerging from statistically valid relations will be examined, namely causal (mechanistic), contextual (empirical), fortuitous, and tautological correlations. Implications for ADME predictions will be seen when discussing the diversity of interactions between active compounds (e.g., drugs) and biological systems. The second part of the paper is more specific and presents the concept of molecular-property space, an all but neglected concept in SARs. Recent results from Molecular Dynamics (MD) simulations and Molecular Interaction Fields (MIF) computations of acetylcholine will be used to illustrate not only the well-known conformational space of this molecule, but also its property space as exemplified by its lipophilicity space. It will be seen that a molecule as small as acetylcholine is able to span a relatively broad property space. Most significantly in an ADME perspective, the molecule is able, within the limits of its property space, to adapt to the medium. This is equivalent to saying that the medium constrains the molecule to resemble it as much as feasible. [source]

Solvatochromic Analysis of Partition Coefficients in the o -Nitrophenyl Octyl Ether (o -NPOE)/Water System

HELVETICA CHIMICA ACTA, Issue 11 2003
Xiangli Liu
The objective of this study was to unravel the structural properties responsible for the partitioning of solutes in o -nitrophenyl octyl ether (o -NPOE)/H2O, a new solvent system for the determination of the partition coefficients of ions. A set of 88 compounds (including drugs) was selected to allow a regular and broad distribution of property spaces. Partition coefficients in o -NPOE/H2O (log,Pnpoe) were measured by the shake-flask or the potentiometric method. Linear solvation free-energy relationship (LSER) analyses showed that Van der Waals volume, H-bond-acceptor basicity, and H-bond-donor acidity are the three molecular descriptors of solutes determining their log,Pnpoe values. The partitioning mechanism of the investigated compounds in o -NPOE/H2O is controlled by the same structural properties as it is in 1,2-dichloroethane (DCE)/H2O. ,log,Poct,npoe Values (difference between log,Poct and log,Pnpoe) express mainly dipolarity/polarizability and H-bond-donor acidity. The solvent o -NPOE is shown to be a good candidate to replace DCE in measurements of lipophilicity. [source]

Shifting Common Spaces of Plant Genetic Resources in the International Regulation of Property

THE JOURNAL OF WORLD INTELLECTUAL PROPERTY, Issue 3 2008
Carolina Roa-Rodríguez
The appellative "common heritage of mankind" is often used as a description of the property domain that governed plant genetic resources (PGR) at an international level up until the end of the twentieth century. However, the concept is rarely elaborated on. In this article we explore the origins of common property in PGR and the shifting content and shape of the genetic commons over the past several decades. Using the theoretical framework of diverse common property regimes developed by Peter Drahos, we chart the way in which the emergence and interaction of various international regulatory regimes related to PGR reshape common property spaces, rights and obligations. We argue that these international agreements do not regulate a single property domain in isolation, but rather modify the content and boundaries of the complex set of property domains that apply to PGR: private, state, common and public. More than a theoretical conundrum, we show that any realistic appraisal of the implementation of the international regulatory regimes in relation to PGR must acknowledge the conflicting and complex dynamics of these interrelated property domains, as well as the way in which they are being put into place on the ground. [source]

Atomic Diversity, Molecular Diversity, and Chemical Diversity: The Concept of Chemodiversity

CHEMISTRY & BIODIVERSITY, Issue 8 2009
Bernard Testa
Abstract This minireview is meant as an introduction to the following paper. To this end, it presents the general background against which the joint paper should be understood. The first objective of the present paper is thus to clarify some concepts and related terminology, drawing a clear distinction between i) atomic diversity (i.e., atomic-property space), ii) molecular or macromolecular diversity (i.e., molecular- or macromolecular-property spaces), and iii) chemical diversity (i.e., chemical-diversity space). The first refers to the various electronic states an atom can occupy. The second encompasses the conformational and property spaces of a given (macro)molecule. The third pertains to the diversity in structure and properties exhibited by a library or a supramolecular assembly of different chemical compounds. The ground is thus laid for the content of the joint paper, which pertains to case ii, to be placed in its broader chemodiversity context. The second objective of this paper is to point to the concepts of chemodiversity and biodiversity as forming a continuum. Chemodiversity is indeed the material substratum of organisms. In other words, chemodiversity is the material condition for life to emerge and exist. Increasing our knowledge of chemodiversity is thus a condition for a better understanding of life as a process. [source]