Automakers used laminated glass in their windshields to optimize occupant safety during accidents and to protect passengers from projectiles during normal driving conditions. For all its benefits, though, the first types of laminated glass offered limited puncture resistance. Today's laminated glass consists of a thin layer of polyvinyl butyral PVB inserted between two layers of solid glass. In addition to laminated glass, automakers began to use tempered glass in the late s.
This type of glass is used in the vehicle's side and back windows and gains its strength through a heating and rapid cooling process that strengthens the glass' outer surface as well as its core. By the s, the American public had become increasingly aware that automobiles needed to be designed for more than just looks. This realization derived partly from consumer crusader Ralph Nader 's work to expose the dangers posed by certain vehicles and the need for government safety standards.
In response, the U. For Instructors Request Inspection Copy.
The Role of the Chemist in Automotive Design by H.K. Phlegm (Hardback, 2009)
A glance through the table of contents provides an overview of the issues commonly encountered by chemists in the automotive industry. The author discusses fuels cells, lithium ion batteries, carbon nanotubes, and nickel metal hydride technology, all of which require the technical knowledge of a chemist but cross the lines of various disciplines. He also covers future technology including items such as battery technology, fuel cell membranes, and environmentally friendly plastics such as nylons that use castor oil as a primary component.
The book examines environmental concerns such as CARB legislation and how the industry plans to deal with the new legislation with strategies such as Ozone Reduction Catalyst.
The increasing technological, environmental, and economic issues facing the auto industry underscores the need for a basic reference that covers technologies that can be used to make vehicle more fuel efficient, environmentally friendly, and cost efficient. Exploring the expanding role chemists will play in future automotive design and technology, this book delineates the areas and technologies that require the technical knowledge of a chemist but that cross the lines of many disciplines. We provide complimentary e-inspection copies of primary textbooks to instructors considering our books for course adoption.
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These other molecules may be used to derive a pharmacophore model that defines the minimum necessary structural characteristics a molecule must possess in order to bind to the target. Alternatively, a quantitative structure-activity relationship QSAR , in which a correlation between calculated properties of molecules and their experimentally determined biological activity, may be derived. These QSAR relationships in turn may be used to predict the activity of new analogs.
Structure-based drug design or direct drug design relies on knowledge of the three dimensional structure of the biological target obtained through methods such as x-ray crystallography or NMR spectroscopy. Using the structure of the biological target, candidate drugs that are predicted to bind with high affinity and selectivity to the target may be designed using interactive graphics and the intuition of a medicinal chemist.
Alternatively various automated computational procedures may be used to suggest new drug candidates. Current methods for structure-based drug design can be divided roughly into three main categories. This method is known as virtual screening. A second category is de novo design of new ligands. In this method, ligand molecules are built up within the constraints of the binding pocket by assembling small pieces in a stepwise manner.
These pieces can be either individual atoms or molecular fragments. The key advantage of such a method is that novel structures, not contained in any database, can be suggested. Binding site identification is the first step in structure based design. However, there may be unoccupied allosteric binding sites that may be of interest.
Furthermore, it may be that only apoprotein protein without ligand structures are available and the reliable identification of unoccupied sites that have the potential to bind ligands with high affinity is non-trivial.
In brief, binding site identification usually relies on identification of concave surfaces on the protein that can accommodate drug sized molecules that also possess appropriate "hot spots" hydrophobic surfaces, hydrogen bonding sites, etc. Structure-based drug design attempts to use the structure of proteins as a basis for designing new ligands by applying the principles of molecular recognition.
Selective high affinity binding to the target is generally desirable since it leads to more efficacious drugs with fewer side effects. Thus, one of the most important principles for designing or obtaining potential new ligands is to predict the binding affinity of a certain ligand to its target and known antitargets and use the predicted affinity as a criterion for selection. A more general thermodynamic "master" equation is as follows: The basic idea is that the overall binding free energy can be decomposed into independent components that are known to be important for the binding process.
Each component reflects a certain kind of free energy alteration during the binding process between a ligand and its target receptor. The Master Equation is the linear combination of these components. According to Gibbs free energy equation, the relation between dissociation equilibrium constant, K d , and the components of free energy was built. Various computational methods are used to estimate each of the components of the master equation.
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For example, the change in polar surface area upon ligand binding can be used to estimate the desolvation energy. The number of rotatable bonds frozen upon ligand binding is proportional to the motion term.
The configurational or strain energy can be estimated using molecular mechanics calculations. Finally the interaction energy can be estimated using methods such as the change in non polar surface, statistically derived potentials of mean force , the number of hydrogen bonds formed, etc.
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In practice, the components of the master equation are fit to experimental data using multiple linear regression. This can be done with a diverse training set including many types of ligands and receptors to produce a less accurate but more general "global" model or a more restricted set of ligands and receptors to produce a more accurate but less general "local" model. A particular example of rational drug design involves the use of three-dimensional information about biomolecules obtained from such techniques as X-ray crystallography and NMR spectroscopy.
Computer-aided drug design in particular becomes much more tractable when there is a high-resolution structure of a target protein bound to a potent ligand.
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This approach to drug discovery is sometimes referred to as structure-based drug design. The first unequivocal example of the application of structure-based drug design leading to an approved drug is the carbonic anhydrase inhibitor dorzolamide , which was approved in Another important case study in rational drug design is imatinib , a tyrosine kinase inhibitor designed specifically for the bcr-abl fusion protein that is characteristic for Philadelphia chromosome -positive leukemias chronic myelogenous leukemia and occasionally acute lymphocytic leukemia.
Imatinib is substantially different from previous drugs for cancer , as most agents of chemotherapy simply target rapidly dividing cells, not differentiating between cancer cells and other tissues. It has been argued that the highly rigid and focused nature of rational drug design suppresses serendipity in drug discovery.
Furthermore, the rational design of a drug may be limited by a crude or incomplete understanding of the underlying molecular processes of the disease it is intended to treat [54].