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Showing 17,701 through 17,725 of 72,788 results

Direct-Fed Microbials and Prebiotics for Animals: Science and Mechanisms of Action

by Todd R. Callaway Steven C. Ricke

In this exciting update, readers will learn how feeding direct-fed microbials (including eubiotics, postbiotics, prebiotics, and synbiotics) is becoming increasingly widespread during food animal production. Animal production must improve efficiency of growth, and the use of direct-fed microbial and prebiotic additives to domestic animals has become widely accepted and utilized. The benefits of probiotic-type approaches in cattle, pigs, fish, and poultry, include improved general animal health, reduced foodborne pathogen populations, increased growth rate and feed efficiency, improved milk and egg production, and have been reported world-wide. Successes from probiotic approaches in multiple species have ensured their adoption; however, several fundamental questions remain. Early establishment and retention of an ecological balance in the gastrointestinal tract is an important first step for an external biological additive to be effective in young animals, suggesting that some of the benefits of direct-fed microbials may be due to an early establishment of a “normal” native gut microbial population. Research has indicated that the establishment of a normal population can enhance gut epithelial integrity, preventing inflammation and improving animal health. Thus, it is important that we understand the key processes that occur during the establishment of the gut microbial population that can impact gastrointestinal fermentation and provide protection against pathogens of the animals and of human consumers. Knowing how these processes work and how they impact animal energy and protein expenditures can guide further improvements of available and future commercial products. Exciting research opportunities are discussed in this book, examining different characteristics of DFMs that are fed to animals to meet different production demands in different production scenarios (e.g., beef versus dairy versus swine versus fin fish). The advent of molecular and next-generation sequencing offers methods of developing tailored DFMs, and of early detection of successful DFM establishment in the gut. These techniques will further deepen our insight into understanding the microbial population of the gut and how these populations impact animal health, food safety, and sustainability of animal-derived protein production.

Direct-Fed Microbials and Prebiotics for Animals

by Todd R. Callaway Steven C. Ricke

The practice of supplementing direct fed microbial and prebiotic additives to domestic animals during growth is becoming more widespread in food animal production. Beneficial effects particularly in cattle, pigs and poultry, including improved general health, foodborne pathogen reduction, more efficient food utilization, faster growth rate and increased milk and egg production are common results. The success associated with direct fed microbial and prebiotic applications in multiple species ensures their continued commercialization and the widespread use of such additives. However, several fundamental questions remain about how and why probiotic products work, and which kind of probiotic products are best for specific production scenarios. It appears that early establishment and retention of an ecological balance in the gastrointestinal tract is an important first step for an external biological additive to be effective in young animals. Therefore, it is possible that the effectiveness of direct fed microbials and prebiotics in some animal species may only be an indirect consequence of speeding up the establishment and succession of the dominant microflora characteristic of the adult gastrointestinal tract. Consequently, an understanding of the key processes during establishment of microflora in the gastrointestinal system that lead to the subsequent fermentation characteristics and ecological balance exhibited by the highly protective microflora is needed. Several additional areas of future research directions are also suggested for further development and implementation of these biological approaches as new molecular and drug delivery technologies become available. Continued research on direct fed microbials and prebiotics in general should markedly expand their commercial applications.

Direct Hydroxylation of Methane: Interplay Between Theory and Experiment

by Kazunari Yoshizawa

This book focuses on theoretical and computational studies by the editor’s group on the direct hydroxylation of methane, which is one of the most challenging subjects in catalyst chemistry. These studies of more than 20 years include gas-phase reactions by transition-metal oxide ions, enzymatic reactions by two types of methane monooxygenase (soluble and particulate MMO), catalytic reactions by metal-exchanged zeolites, and methane C–H activation by metal oxide surfaces. Catalyst chemistry has been mostly empirical and based on enormous experimental efforts. The subject of the title has been tackled using the orbital interaction and computations based on extended Hückel, DFT, and band structure calculations. The strength of the theoretical studies is in the synergy between theory and experiment. Therefore, the group has close contacts with experimentalists in physical chemistry, catalyst chemistry, bioinorganic chemistry, inorganic chemistry, and surface chemistry. This resulting book will be useful for the theoretical analysis and design of catalysts.

Direct Measurement of the Hyperfine Structure Interval of Positronium Using High-Power Millimeter Wave Technology

by Akira Miyazaki

In this thesis, the author develops new high-power millimeter wave techniques for measuring the hyperfine structure of positronium (Ps-HFS) directly for the first time in the world. Indirect measurement of Ps-HFS in the literature might have systematic uncertainties related to the use of a static magnetic field. Development of the millimeter wave devices supports the precise determination of Ps-HFS by directly measuring the Breit-Wigner resonant transition from o-Ps to p-Ps without the magnetic field. At the same time, the width of the measured Breit-Wigner resonance directly provides the lifetime of p-Ps. This measurement is the first precise spectroscopic experiment involving the magnetic dipole transition and high-power millimeter waves. The development of a gyrotron and a Fabry-Pérot cavity is described as providing an effective power of over 20 kW, which is required to cause the direct transition from o-Ps to p-Ps. Those values measured by the newly developed millimeter wave device pave the way for examining the discrepancy observed between conventional indirect experiments on Ps-HFS and the theoretical predictions of Quantum Electrodynamics.

Direct Mechanisms in Cholesterol Modulation of Protein Function (Advances in Experimental Medicine and Biology #1135)

by Avia Rosenhouse-Dantsker Anna N. Bukiya

In this book, renowned scientists describe how cholesterol interacts with various proteins. Recent progress made in the high-resolution visualization of cholesterol-protein interactions using crystallography and cryogenic electron microscopy has substantially advanced the knowledge of critical features. These features enable specific recognition of the cholesterol molecule by proteins, a process that was built on earlier studies using binding assays, computational modeling and site-directed mutagenesis. Direct Mechanisms in Cholesterol Modulation of Protein Function offers comprehensive insights into the current understanding of cholesterol-driven modulation of protein function via direct sensing. Its nine chapters are organized into two distinct parts. In the first part, the chapters introduce the reader to the general characteristics of cholesterol binding sites in proteins. This part starts with a tour into common cholesterol recognition motifs, followed by an overview of the major classes of steroid-binding proteins. It then continues with two chapters that present a comprehensive analysis of molecular and structural characteristics of cholesterol binding sites in transmembrane and soluble protein domains. In the second part of the book, examples of cholesterol binding sites and consequences of specific cholesterol recognition for protein function are presented for G protein-coupled receptors, ion channels and cholesterol-transporting proteins. The book is valuable for undergraduate and graduate students in biochemistry and nutrition, as well as basic science and medical researchers with a keen interest in the biophysical properties of cholesterol and physiological consequences of cholesterol presence in biological systems.

Direct Methods: Methodological Progress and Engineering Applications (Lecture Notes in Applied and Computational Mechanics #95)

by Aurora Angela Pisano Konstantinos Vassilios Spiliopoulos Dieter Weichert

This book provides an overview of direct methods such as limit and shakedown analysis, which are intended to do away with the need for cumbersome step-by-step calculations and determine the loading limits of mechanical structures under monotone, cyclic or variable loading with unknown loading history. The respective contributions demonstrate how tremendous advances in numerical methods, especially in optimization, have contributed to the success of direct methods and their practical applicability to engineering problems in structural mechanics, pavement and general soil mechanics, as well as the design of composite materials. The content reflects the outcomes of the workshop “Direct Methods: Methodological Progress and Engineering Applications,” which was offered as a mini-symposium of PCM-CMM 2019, held in Cracow, Poland in September 2019.

Direct Methods for Limit State of Materials and Structures: Advanced Computational Algorithms and Material Modelling (Lecture Notes in Applied and Computational Mechanics #101)

by Giovanni Garcea Dieter Weichert

This book provides an overview of direct methods, such as limit and shakedown analysis, which are intended for avoiding cumbersome step-by-step calculations to determine the limit states of mechanical structures under monotone, cyclic or variable actions with unknown loading history. The book comprises several contributions that demonstrate how tremendous advances in numerical methods, especially in optimization, have contributed to the success of direct methods and their applicability to practical engineering problems in structural mechanics and mechanics of materials. The contents reflect the outcomes of the workshop “Direct Methods for Limit State of Materials and Structures,” held in Cosenza, Italy in June 2022.

Direct Natural Gas Conversion to Value-Added Chemicals

by Jianli Hu Dushyant Shekhawat

Direct Natural Gas Conversion to Value-Added Chemicals comprehensively discusses all major aspects of natural gas conversion and introduces a broad spectrum of recent technological developments. Specifically, the book describes heterogeneous and homogeneous catalysis, microwave-assisted conversion, non-thermal plasma conversion, electrochemical conversion, and novel chemical looping conversion approaches. Provides an excellent benchmark resource for the industry and academics Appeals to experienced researchers as well as newcomers to the field, despite the variety of contributing authors and the complexity of the material covered Includes all aspects of direct natural gas conversion: fundamental chemistry, different routes of conversion, catalysts, catalyst deactivation, reaction engineering, novel conversion concepts, thermodynamics, heat and mass transfer issues, system design, and recent research and development Discusses new developments in natural gas conversion and future challenges and opportunities This book is as an excellent resource for advanced students, technology developers, and researchers in chemical engineering, industrial chemistry, and others interested in the conversion of natural gas.

Direct-to-Consumer Genetic Testing: Summary of a Workshop

by Institute of Medicine National Research Council of the National Academies

Today, scores of companies, primarily in the United States and Europe, are offering whole genome scanning services directly to the public. The proliferation of these companies and the services they offer demonstrate a public appetite for this information and where the future of genetics may be headed; they also demonstrate the need for serious discussion about the regulatory environment, patient privacy, and other policy implications of direct-to-consumer (DTC) genetic testing. Rapid advances in genetic research already have begun to transform clinical practice and our understanding of disease progression. Existing research has revealed a genetic basis or component for numerous diseases, including Parkinson's disease, Alzheimer's disease, diabetes, heart disease, and several forms of cancer. The availability of the human genome sequence and the HapMap, plummeting costs of high-throughput screening, and increasingly sophisticated computational analyses have led to an explosion of discoveries of linkages between patterns of genetic variation and disease susceptibility. While this research is by no means a straight path toward better public health, improved knowledge of the genetic linkages has the potential to change fundamentally the way health professionals and public health practitioners approach the prevention and treatment of disease. Realizing this potential will require greater sophistication in the interpretation of genetic tests, new training for physicians and other diagnosticians, and new approaches to communicating findings to the public. As this rapidly growing field matures, all of these questions require attention from a variety of perspectives. To discuss some of the foregoing issues, several units of the National Academies held a workshop on August 31 and September 1, 2009, to bring together a still-developing community of professionals from a variety of relevant disciplines, to educate the public and policy-makers about this emerging field, and to identify issues for future study. The meeting featured several invited presentations and discussions on the many technical, legal, policy, and ethical questions that such DTC testing raises, including: (1) overview of the current state of knowledge and the future research trajectory; (2) shared genes and emerging issues in privacy; (3) the regulatory framework; and (4) education of the public and the medical community.

Directed-Energy Beam Weapons

by Bahman Zohuri

This book introduces modern directed-energy beam weaponry and emerging technical concepts based on unclassified and declassified information. The book covers laser systems, analyzing the interaction between high-power laser beams and matter, and examines penetration of high power beams such as microwave and scalar wave. It also covers the use of particle and high-power radar beams and scalar wave as weapons of the future. In-depth coverage of the relevant mathematical and engineering topics and concepts are included. The book will provide scientists and engineers with valuable guidance on the fundamentals needed to understand state-of-the-art directed energy weaponry technology research and applications.Provides guidance on the fundamentals of state-of-the-art directed-energy weaponry technology;Introduces the physics behind directed-energy weapons;Offers in-depth coverage of mathematical and engineering topics.

Directed Enzyme Evolution: Advances and Applications

by Miguel Alcalde

This book focuses on some of the most significant advances in enzyme engineering that have been achieved through directed evolution and hybrid approaches. On the 25th anniversary of the discovery of directed evolution, this volume is a tribute to the pioneers of this thrilling research field, and at the same time provides a comprehensive overview of current research and the state of the art. Directed molecular evolution has become the most reliable and robust method to tailor enzymes, metabolic pathways or even whole microorganisms with improved traits. By mirroring the Darwinian algorithm of natural selection on a laboratory scale, new biomolecules of invaluable biotechnological interest can now be engineered in a manner that surpasses the boundaries of nature. The volume is divided into two sections, the first of which provides an update on recent successful cases of enzyme ensembles from different areas of the biotechnological spectrum, including tryptophan synthases, unspecific peroxygenases, phytases, therapeutic enzymes, stereoselective enzymes and CO2-fixing enzymes. This section also provides information on the directed evolution of whole cells. The second section of the book summarizes a variety of the most applicable methods for library creation, together with the future trends aimed at bringing together directed evolution and in silico/computational enzyme design and ancestral resurrection.

Directed Enzyme Evolution

by George Georgiou Frances H. Arnold

Seasoned practitioners from many leading laboratories describe their best readily reproducible screening strategies for isolating useful clones. These techniques have been optimized for sensitivity, high throughput, and robustness, and are of proven utility for directed evolution purposes. The assays presented use a variety of techniques, including genetic complementation, microtiter plates, solid-phase screens with colorimetric substrates, and flow cytometric screens. An accompanying volume, Directed Evolution Library Creation: Methods and Protocols (ISBN 1-58829-285-1), describes readily reproducible methods for the creation of mutated DNA molecules and DNA libraries. Copy for Both Volumes Directed Evolution Library Creation: Methods and Protocols and Directed Enzyme Evolution: Screening and Selection Methods constitute an extraordinary collection of all the key methods used today for directed evolution research. Described in step-by-step detail to ensure robust experimental results, these methods will enable both newcomers and more experienced investigators to design and implement directed evolution strategies for the engineering of novel proteins. The first volume describes methods for the creation of mutated DNA molecules, or DNA libraries, encoding variants of desired proteins. The second volume describes methods for screening DNA libraries to isolate mutant proteins that exhibit a specified function.

Directed Evolution: Methods and Protocols (Methods in Molecular Biology #2461)

by Andrew Currin Neil Swainston

This volume explores the latest techniques used by researchers to study directed evolution (DE) at each stage of the Design-Build-Test-Learn cycle. Chapters in this book cover topics such as designing overlap extension PCR primers for protein mutagenesis; antha-guided automation of Darwin assembly for the construction of bespoke gene libraries; rapid cloning of random mutagenesis libraries using PTO-Quickstep; and DE of glycosyltransferases by a single-cell screening method. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Cutting-edge and comprehensive, Directed Evolution: Methods and Protocols is a valuable resource for scientists and researchers who are interested in learning more about this field and incorporating these studies into new experimental workflows.

Directed Evolution for Development and Production of Bioactive Agents

by Daniel Talmage

In 2012, the Defense Intelligence Agency (DIA) approached the National Research Council and asked that a committee be formed to develop a list of workshop topics to explore the impact of emerging science and technology. This book explains the objectives of the workshop.

Directed Evolution Library Creation

by Elizabeth M.J. Gillam Janine N. Copp David Ackerley

Directed Evolution Library Creation: Methods and Protocols, Second Edition presents user-friendly protocols for both proven strategies and cutting-edge approaches for the creation of mutant gene libraries for directed evolution. As well as experimental methods, information on current computational approaches is provided in a user-friendly format that will allow researchers to make informed choices without needing to comprehend the full technical details of each algorithm. Directed evolution has become a fundamental approach for engineering proteins to enhance activity and explore structure-function relationships, and has supported the rapid development of the field of synthetic biology over the last decade. Divided into three convenient sections, topics include point mutagenesis strategies, recombinatorial methods wherein genetic diversity is sourced from multiple parental genes that are combined via either homology-dependent or -independent techniques and a variety of computational methods to guide the design and analysis of mutant libraries. Written in the successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible protocols and notes on troubleshooting and avoiding known pitfalls. Authoritative and easily accessible, Directed Evolution Library Creation: Methods and Protocols, Second Edition will serve as a reliable manual for both novice and experienced protein engineers and synthetic biologists and will enable further technical innovation and the exploitation of directed evolution for a deeper understanding of protein design and function.

Directed Evolution Library Creation

by George Georgiou Frances H. Arnold

A comprehensive compendium of cutting-edge protocols for the generation of molecular diversity. Described in step-by-step detail to ensure experimental success, these protocols include readily reproducible methods for random mutagenesis of entire genes or segments of genes, for homologous and nonhomologus recombination, and for constructing in vivo libraries in bacteria and yeast. In addition to the various protocols for creating libraries, this volume also describes ways to analyze libraries, particularly those made by recombination. An accompanying volume, Directed Enzyme Evolution: Screening and Selection Methods (ISBN: 1-58829-286-X), is devoted entirely to selection and screening methods that can be applied to the directed evolution of enzymes. Copy for Both Volumes Directed Evolution Library Creation: Methods and Protocols and Directed Enzyme Evolution: Screening and Selection Methods constitute an extraordinary collection of all the key methods used today for directed evolution research. Described in step-by-step detail to ensure robust experimental results, these methods will enable both newcomers and more experienced investigators to design and implement directed evolution strategies for the engineering of novel proteins. The first volume describes methods for the creation of mutated DNA molecules, or DNA libraries, encoding variants of desired proteins. The second volume describes methods for screening DNA libraries to isolate mutant proteins that exhibit a specified function.

Directed Evolution of Selective Enzymes: Catalysts for Organic Chemistry and Biotechnology

by Manfred T. Reetz

Authored by one of the world's leading organic chemists, this authoritative reference provides an overview of basic strategies in directed evolution and introduces common gene mutagenesis, screening and selection methods. Throughout the text, emphasis is placed on methodology development to maximize efficiency, reliability and speed of the experiments and to provide guidelines for efficient protein engineering. Professor Reetz highlights the application of directed evolution experiments to address limitations in the field of enzyme selectivity, substrate scope, activity and robustness. He critically reviews recent developments and case studies, takes a look at future applications in the field of organic synthesis, and concludes with lessons learned from previous experiments.

Directed Selectivity in Organic Synthesis

by Tanja Gaich Ekkehard Winterfeldt

Is it possible to have access to all stereoisomers if you begin your synthesis with only one single starting material? This book shows ways and concepts how this can be achieved by using the right reagents, conditions or reaction sequences. Especially if the starting material is very cheap or readily available this approach has a very high value in academia and industry for example to build up a new compound library. This unique textbook presents numerous examples of this so-called "directed selectivity" which are often hidden in the original literature. The text is highly useful for every organic chemistry student.

Direction of Time

by Sergio Albeverio Philippe Blanchard

This edited book presents the problems of time and direction from an interdisciplinary point of view, concentrating in particular on the following relations: * Time and physics * Time, philosophy and psychology * Time, mathematics and information theory It is a unique contribution by philosophers and scientists who are active in mathematics, physics, biology, engineering, information theory and psychology. Questions such as the existence of a Big Bang, the neurobiological basis regarding the coexistence of free will and determinism, intercultural aspects of time, mathematical models of time, psychopathological features of time, and micro reversibility versus macroscopic irreversibility are studied. It also provides a truly interdisciplinary study of the problematic 'arrow of time'.

The Direction of Time

by Hans Reichenbach

Ever a source of philosophical conjecture and debate, the concept of time represents the beating heart of physics. This final work by the distinguished physicist Hans Reichenbach represents the culmination and integration of a lifetime's philosophical contributions and inquiries into the analysis of time. The result is an outstanding overview of such qualitative, or topological, attributes of time as order and direction.Beginning with a discussion of the emotive significance of time, Reichenbach turns to an examination of the time order of mechanics, the time direction of thermodynamics and microstatistics, the time direction of macrostatistics, and the time of quantum physics. He offers coherent explanations of the analytic methods of scientific philosophy in the investigation of probability, quantum mechanics, the theory of relativity, and causality — methods that he not only applies here but also helped to develop and refine.Physics Today observed that "For a generation Professor Reichenbach has worked as almost no other man to bring to the interpretation of modern physics the critical and reflective thinking of a trained philosopher. Most physicists who retain an interest in philosophy, and many who wanted simply to understand physics, have read some of the earlier books of Reichenbach. This one is . . . the best by a good deal." Introduction. Appendix. Index.

Directory of Approved Biopharmaceutical Products

by Stefania Spada Gary Walsh

Biopharmaceuticals, the term for genetically engineered therapeutic proteins, monoclonal antibodies, and nucleic acid-based products, have become an increasing part of the pharmaceutical armament. While this category of drugs accounts for approximately 25% of all new drugs coming to market, very few references exist that review these commercially a

Directory of Microbicides for the Protection of Materials

by Wilfried Paulus

This edition is divided into two parts. Part One presents extensively diversified contributions from 23 world experts, on such topics as: Microbicides with regard to the relationship between chemical structure and mode of action and activity; Research and development in consideration of registration procedures; Legislative aspects. The use of microbicides in 18 major application areas are described in detail. Part Two collects Microbicide Data, organized into 21 substance classes (e.g. alcohols, aldehydes, acids, amides, etc.), and including some 300 entries.

Directory of Therapeutic Enzymes

by Gary Walsh Barry M. McGrath

Carefully crafted to provide tightly focused and authoritative information, the Directory of Therapeutic Enzymes covers all approved therapeutic enzymes currently used in medicine. Written mainly by industry experts, the book includes information sourced directly from the company that developed or manufactured the product. It explores major

Dirofilariasis

by P. F. Boreham

Heartworm disease is probably the most well-known disease of dogs, and its epidemiology is being recorded in those countries in which the disease is routinely treated in the domestic dog. It is hoped that this text will be of benefit to us all and that our understanding of this disease will continue to grow and so enable us to resolve some of the exsiting problems associated with the treatment of this disease. To this end, the book aims to project some hypotheses in different areas that, while unproven, seem to be the most probable, based on our current knowledge.

Dirt Rich, Dirt Poor: America's Food and Farm Crisis (Routledge Library Editions: Agriculture #9)

by Joseph N. Belden Vincent P. Wilber Enid Kassner Rus Sykes Ed Cooney Lynn Parker Alan Sanders Cynthia Schneider Marsha Simon

This book, first published in 1986, is a major reference work for the political discussions arising out of the 1985 Congress revisions of US food and farm laws. It covers production, distribution and consumption of food, analyses international as well as domestic problems, and presents new ways forward. Emphasising public policy and programmes, the book has chapters on agricultural production; environmental and resource problems; food marketing; domestic hunger and nutrition; and world hunger and development.

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