Download or read book On Chirality and the Universal Asymmetry written by Georges H. Wagnière and published by John Wiley & Sons. This book was released on 2008-09-26 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Until half a century ago, it was assumed that the forces of nature were symmetric and that they did not distinguish between right and left, between image and mirror image. The discovery of the violation of parity in 1956 was more than a sensation, for some it was a shock. It implied that the universe displays handedness, or chirality, and that it is fundamentally asymmetric. Remarkably, a most striking asymmetry is encountered in the realm of biology. Living organisms contain proteins built almost exclusively from L-amino acids, and nucleic acids derived from D-sugars only. Yet a mirror-image biochemistry, based on D-amino acids and L-sugars is, from a purely chemical standpoint, entirely conceivable. Where, then, does this extraordinary natural selectivity come from? Is it directly, or indirectly, connected to the universal violation of parity? This book is meant as a brief review of the various manifestations of handedness, or chirality, in the universe. It does not attempt to present a solution to basic questions which perhaps will never be unambiguously and conclusively answered. Rather, it is an excursion through nature, to observe and recognize how the chirality manifests itself at different structural levels. The excursion starts in the chemistry and physics laboratory. Then a journey into outer space and back in time is undertaken. After a return to our planet Earth, the focus is on the development of living organisms. The text should be accessible to anyone having the equivalent of a first-year university instruction in physics and chemistry. It is also hoped that a layperson with a more modest scientific formation may gain a general impression of the basic asymmetry in nature and of the fundamental significance of chirality. Mathematical expressions, wherever they occur, may then be overlooked. Some more difficult sections may be skipped. A Glossary preceding the Subject Index should be helpful.

Download or read book Mirror Image Asymmetry written by James P. Riehl and published by John Wiley & Sons. This book was released on 2010-03-22 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the importance and consequences of asymmetry from molecules to the macroscopic world As scientists have become more capable of probing the structure of three-dimensional objects at the molecular level, the need to understand the concept and the consequences of mirror-image asymmetry—chirality—has increased enormously. Written at an introductory level, Mirror-Image Asymmetry provides an overview of the importance and effects of asymmetry from the atomic and molecular world of physics and chemistry to the organisms and structures that we see and use in our everyday life. The reader will develop a broad appreciation of three-dimensional asymmetry from the microscopic molecular world to the macroscopic world of handedness, automobile driving, windmills, sports, and similar phenomena. The book features: An introduction to basic definitions and the nomenclature of asymmetric and dissymmetric molecules Up-to-date examples of the importance and consequences of asymmetry in modern drug applications, current theories of the origin of asymmetry in nature, and examples of molecular asymmetry in smell, taste, and insect communication Many illustrations, chemical structures, and photographs that enable the reader to connect the actual asymmetrical structures to the different phenomena that depend on structural asymmetry In the 150 years since Louis Pasteur discovered asymmetry in molecular structures, scientists have made great progress in understanding how interactions between chiral molecules influence biochemical processes. This knowledge is leading to very sophisticated asymmetric synthetic techniques that have greatly benefitted many research groups especially those in the pharmaceutical industry. This guide to the role of molecular and macroscopic chirality will inspire students and scientists in chemistry, biology, physics, and drug discovery.

Download or read book Mirror Image Asymmetry written by James P. Riehl and published by John Wiley & Sons. This book was released on 2011-04-22 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the importance and consequences of asymmetry from molecules to the macroscopic world As scientists have become more capable of probing the structure of three-dimensional objects at the molecular level, the need to understand the concept and the consequences of mirror-image asymmetry—chirality—has increased enormously. Written at an introductory level, Mirror-Image Asymmetry provides an overview of the importance and effects of asymmetry from the atomic and molecular world of physics and chemistry to the organisms and structures that we see and use in our everyday life. The reader will develop a broad appreciation of three-dimensional asymmetry from the microscopic molecular world to the macroscopic world of handedness, automobile driving, windmills, sports, and similar phenomena. The book features: An introduction to basic definitions and the nomenclature of asymmetric and dissymmetric molecules Up-to-date examples of the importance and consequences of asymmetry in modern drug applications, current theories of the origin of asymmetry in nature, and examples of molecular asymmetry in smell, taste, and insect communication Many illustrations, chemical structures, and photographs that enable the reader to connect the actual asymmetrical structures to the different phenomena that depend on structural asymmetry In the 150 years since Louis Pasteur discovered asymmetry in molecular structures, scientists have made great progress in understanding how interactions between chiral molecules influence biochemical processes. This knowledge is leading to very sophisticated asymmetric synthetic techniques that have greatly benefitted many research groups especially those in the pharmaceutical industry. This guide to the role of molecular and macroscopic chirality will inspire students and scientists in chemistry, biology, physics, and drug discovery.

Download or read book Principles of Asymmetric Synthesis written by Robert E. Gawley and published by Elsevier. This book was released on 2012-07-16 with total page 569 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world is chiral. Most of the molecules in it are chiral, and asymmetric synthesis is an important means by which enantiopure chiral molecules may be obtained for study and sale. The aim of this book is to present a detailed analysis of the factors that govern stereoselectivity in organic reactions.

Download or read book Possible Scenarios for Homochirality on Earth written by Michiya Fujiki and published by Buy this from MDPI Books. This book was released on 2019-11-14 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1978, Fred Hoyle proposed that interstellar comets carrying several viruses landed on Earth as part of the panspermia hypotheses. With respect to life, the origin of homochirality on Earth has been the greatest mystery because life cannot exist without molecular asymmetry. Many scientists have proposed several possible hypotheses to answer this long-standing L-D question. Previously, Martin Gardner raised the question about mirror symmetry and broken mirror symmetry in terms of the homochirality question in his monographs (1964 and 1990). Possible scenarios for the L-D issue can be categorized into (i) Earth and exoterrestrial origins, (ii) by-chance and necessity mechanisms, and (iii) mirror-symmetrical and non-mirror-symmetrical forces as physical and chemical origins. These scenarios should involve further great amplification mechanisms, enabling a pure L- or D-world.

Download or read book Chirality at the Nanoscale written by David B. Amabilino and published by John Wiley & Sons. This book was released on 2009-02-11 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: The only standard reference in this exciting new field combines the physical, chemical and material science perspectives in a synergic way. This monograph traces the development of the preparative methods employed to create nanostructures, in addition to the experimental techniques used to characterize them, as well as some of the surprising physical effects. The chapters cover every category of material, from organic to coordination compounds, metals and composites, in zero, one, two and three dimensions. The book also reviews structural, chemical, optical, and other physical properties, finishing with a look at the future for chiral nanosystems.

Download or read book Fundamentals Of Supramolecular Chirality written by Roberto Purrello and published by World Scientific. This book was released on 2021-10-18 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Supramolecular Chirality is a critical description of the start and advancement of supramolecular chirality. This book focuses on the noncovalent approach with some supplementary examples of covalent supramolecular chirality.This contribution to supramolecular chirality is not intended to be a mere catalogue and description of the work done. It also traces a philosophical path following the development and possible perspectives of this topic, providing not a review but a critical examination of the field.

Download or read book Asymmetry in Biological Homochirality written by David Hochberg and published by MDPI. This book was released on 2021-06-04 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chirality, or handedness, is a fundamental physical characteristic, which spans the length scales ranging from elementary particles to the chiral asymmetry of spiral galaxies. The way in which chirality in chemistry, or molecular handedness, may have emerged in a primitive terrestrial environment, and how it can be triggered, amplified, and transferred, are deeply challenging problems rooted in both fundamental scientific interests and the technological potentials for science and society. Chirality constitutes a unifying feature of the living world and is a prime driving force for molecular selection and genetic evolution in biology. In this book, we offer a selection of five distinct approaches to this problem by leading experts in the field. The selected topics range from protein chirality and its relevance to protein ageing, protein aggregation and neurodegeneration, entropy production associated with chiral symmetry breaking in closed systems, chiral oscillations in polymerization models involving higher-order oligomers, the mirror symmetry breaking in liquids and its implications for the development of homochirality in abiogenesis, the role of chirality in the chemical sciences, and some philosophical implications of chirality.

Download or read book Chirality in Supramolecular Assemblies written by F. Richard Keene and published by John Wiley & Sons. This book was released on 2016-12-20 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supramolecular chemistry deals with the organisation of molecules into defined assemblies using non-covalent interactions, including weaker and reversible interactions such as hydrogen bonds, and metal-ligand interactions. The aspect of stereochemistry within such chemical architectures, and in particular chirality, is of special interest as it impacts on considerations of molecular recognition, the development of functional materials, the vexed question of homochirality, nanoscale effects of interactions at interfaces, biocatalysis and enzymatic catalysis, and applications in organic synthesis. Chirality in Supramolecular Assemblies addresses many of these aspects, presenting a broad overview of this important and rapidly developing interdisciplinary field. Topics covered include: Origins of molecular and topological chirality Homochirogenesis Chirality in crystallinity Host-guest behavior Chiral influences in functional materials Chirality in network solids and coordination solids Aspects of chirality at interfaces Chirality in organic assemblies Chirality related to biocatalysis and enzymes in organic synthesis. This book is a valuable reference for researchers in the molecular sciences, materials science and biological science working with chiral supramolecular systems. It provides summaries and special insights by acknowledged international experts in the various fields.

Download or read book Organic Nanomaterials written by Tomas Torres and published by John Wiley & Sons. This book was released on 2013-10-14 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discover a new generation of organic nanomaterials and their applications Recent developments in nanoscience and nanotechnology have given rise to a new generation of functional organic nanomaterials with controlled morphology and well-defined properties, which enable a broad range of useful applications. This book explores some of the most important of these organic nanomaterials, describing how they are synthesized and characterized. Moreover, the book explains how researchers have incorporated organic nanomaterials into devices for real-world applications. Featuring contributions from an international team of leading nanoscientists, Organic Nanomaterials is divided into five parts: Part One introduces the fundamentals of nanomaterials and self-assembled nanostructures Part Two examines carbon nanostructures—from fullerenes to carbon nanotubes to graphene—reporting on properties, theoretical studies, and applications Part Three investigates key aspects of some inorganic materials, self-assembled monolayers, organic field effect transistors, and molecular self-assembly at solid surfaces Part Four explores topics that involve both biological aspects and nanomaterials such as biofunctionalized surfaces Part Five offers detailed examples of how organic nanomaterials enhance sensors and molecular photovoltaics Most of the chapters end with a summary highlighting the key points. References at the end of each chapter guide readers to the growing body of original research reports and reviews in the field. Reflecting the interdisciplinary nature of organic nanomaterials, this book is recommended for researchers in chemistry, physics, materials science, polymer science, and chemical and materials engineering. All readers will learn the principles of synthesizing and characterizing new organic nanomaterials in order to support a broad range of exciting new applications.

Download or read book Chiral Nanomaterials written by Zhiyong Tang and published by John Wiley & Sons. This book was released on 2018-03-05 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thorough and up-to-date, this book presents recent developments in this exciting research field. To begin with, the text covers the fabrication of chiral nanomaterials via various synthesis methods, including electron beam lithography, ion beam etching, chemical synthesis and biological DNA directed assembly. This is followed by the relevant theory and reaction mechanisms, with a discussion of the characterization of chiral nanomaterials according to the optical properties of metal nanoparticles, semiconductor nanocrystals, and nanoclusters. The whole is rounded off by a summary of applications in the field of catalysis, sensors, and biomedicine. With its comprehensive yet concise coverage of the whole spectrum of research, this is invaluable reading for senior researchers and entrants to the field of nanoscience and materials science.

Download or read book Chirality in Drug Design and Synthesis written by C. Brown and published by Academic Press. This book was released on 2013-10-22 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chirality in Drug Design and Synthesis is a collection of papers that discusses the property of asymmetry in the structural and synthetic chemistry of natural products, including the significance of chirality in medicinal chemistry. These papers examine the need for the preparation and study of pure enantiomers of chiral drug substances and their mechanism of interaction with enzymes and receptors. These papers also investigate the techniques in studying these interactions, as well as analyze the methods for their synthesis in enantiomerically pure form. One paper discusses the pharmacological and pharmacokinetic analyses made that point to the differences in the activity and disposition of enantiometric pairs. Another paper reviews the implications of the neglect of stereoselectivity at the different levels during the examination process of racemic drugs. Since no general guidelines exists for the development of drugs with chiral centers, one paper suggests a case-by-case approach in evaluating the safety and efficacy of drugs, particularly as regards how isomers differ in their effects. This collection is suitable for the pharmacologist, medicinal chemists, toxicologists, mechanistic chemists and synthetic organic chemists.

Download or read book Engineering of Crystalline Materials Properties written by Juan J. Novoa and published by Springer Science & Business Media. This book was released on 2007-12-14 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume collects the state of the art in molecular materials. It collects the lecture notes of a series of lectures given by some of the best specialists in the field at the 2007 Erice International School of Crystallography, and also a NATO-ASI course. The school first established "where we are" in terms of modeling, design, synthesis and applications of crystalline solids with predefined properties and then defined current and possible futuristic lines of development.

Download or read book Symmetry and Chirality written by C. Alden Mead and published by . This book was released on 1974 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Symmetry and Chirality written by C. A. Mead and published by . This book was released on 2014-01-15 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Revelation Rationality Knowledge Truth written by Hazrat Mirza Tahir Ahmad and published by Islam International Publications Ltd. This book was released on 1998-06-30 with total page 787 pages. Available in PDF, EPUB and Kindle. Book excerpt: Any divide between revelation and rationality, religion and logic has to be irrational. If religion and rationality cannot proceed hand in hand, there has to be something deeply wrong with either of the two. Does revelation play any vital role in human affairs? Is not rationality sufficient to guide man in all the problems which confront him? Numerous questions such as these are examined with minute attention. All major issues which intrigue the modern mind are attempted to be incorporated in this fascinatingly comprehensive statute. Whatever the intellectual or educational background of the reader, this book is bound to offer him something of his interest. It examines a very diverse and wide range of subjects including the concept of revelation in different religions, history of philosophy, cosmology, extraterrestrial life, the future of life on earth, natural selection and its role in evolution. It also elaborately discusses the advent of the Messiah, or other universal reformers, awaited by different religions. Likewise, many other topical issues which have been agitating the human mind since time immemorial are also incorporated. The main emphasis is on the ability of the Quran to correctly discuss all important events of the past, present and future from the beginning of the universe to its ultimate end. Aided by strong incontrovertible logic and scientific evidence, the Quran does not shy away from presenting itself to the merciless scrutiny of rationality. It will be hard to find a reader whose queries are not satisfactorily answered. We hope that most readers will testify that this will always stand out as a book among books – perhaps the greatest literary achievement of this century.

Download or read book Differentiation of Chiral Compounds Using NMR Spectroscopy written by Thomas J. Wenzel and published by John Wiley & Sons. This book was released on 2018-05-24 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: An updated guide to the most current information available for determining how to use NMR spectroscopy to differentiate chiral compounds Differentiation of Chiral Compounds Using NMR Spectroscopy offers a thoroughly revised second edition to the essential volume that puts the focus on the chiral systems that are commercially available and have been widely vetted for use in NMR spectroscopy. The text covers a broad range of reagents that make it possible to determine the enantiomeric purity and assign the absolute configuration of many classes of compounds. Comprehensive in scope, the text describes the chiral NMR differentiating agents as derivatizing agents, solvating agents, metal-based reagents and liquid crystals and gels, and explains the range and types of compounds for which they can be used for analysis. New to this edition are the most recent findings in the field as well as the development of advanced NMR measurement techniques that allow for the simplification of complex spectra resulting in more readily identified enantiodifferentiation. This important resource: Includes the most recent coverage of a large range of compounds that can be analyzed using chiral NMR reagents Explores the use of chiral NMR reagents and explains their relationship to the stereochemistry of the analyzed molecules Offers the essential information needed to help decide which method is the best NMR method to apply to a class or molecules Contains experimental strategies for using the reagents that are likely to improve the quality of the results Differentiation of Chiral Compounds Using NMR Spectroscopy is a comprehensive guide designed for investigators planning to use NMR spectroscopy to determine enantiomeric purity or assign the absolute configuration of a compound.