elsevier science technology apr 1998 (5 risultati)

Taschenbuch. Condizione: Neu. Neuware - The IFAC International Workshop on Automation in the Steel Industry: Current Practice and Future Development (ASI'97) was held in Kyongju, Korea from 16th to 18th July 1997, with the Steel Processing Automation Research Center (SPARC) serving as the official host. The objective of the workshop was to bring together engineers and scientists with expertise in applying modern control theories and techniques to industrial problems, particularly those involved in the steel industry.

Buch. Condizione: Neu. Neuware - The rapid expansion of the area of free radical biology in the last 25 years has occurred within a framework of assumptions and preconceived notions that has at times directed the course of this movement. The most dominant of these notions has been the view that free radical production is without exception a bad thing, and that the more efficient our elimination of these toxic substances, the better off we will be. The very important observation by Bernard Babior and colleagues in 1973 that activated phagocytes produce superoxide in order to kill micro organisms, served to illustrate that constructive roles are possible for free radicals. For many in the field, however, this merely underscored the deadly nature of oxygen-derived radicals, both from the microbe's point of view and from the host's as well. (Phagocyte-produced superoxide is responsible in part for the tissue injury manifested as inflammation. See Harris and Granger, Chapter 5, and Leff, Hybertson and Repine, Chapter 6.)Mother Nature, however, has a penchant for being able to make a silk purse from a sow's ear. If one is dealt a bad hand, one must simply make the best of it. After two decades of focusing on the destructive side of free radicals, the last few years have begun to reveal a new and finer perspective on free radical metabolism - a role in regulation of cellular function (see Schulze-Osthoff and Baeuerle, Chapter 2). Evidence from a number of sources suggests that an increase in the oxidative status of cell encourages that cell to grow and divide. Increasing the expression of mangnese superoxide dismutase can suppress the malignant phenotype of melanon cells (see Oberley and Oberley, Chapter 3). Oxidative stress beyond a certain poitosis (from the Greek, literally 'to fall apart'). Is this suicide response an evolutionary fail-safe device to curtail tumorogenesis Does oxidative stress-induced apoptosis account for the loss of immune cells in AIDS (see Flores and McCor Chapter 4) This volume attempts to present the spectrum of roles, both good and bad played by active oxygen species as understood at this point in the evolution of this field of free radical biology.

Buch. Condizione: Neu. Neuware - It has been said more than once in psychology that one person's effect is another person's error term. By minimising and occasionally ignoring individual and group variability cognitive psychology has yieled many fine achievements. However, when investigators are working with special populations, the subjects, and the unique nature of the sample, come into focus and become the goal in itself. For developmental psychologists, gerontologists and psychopathologists, research progresses with an eye on their target populations of study. Yet every good study in any of these domains inevitably has another dimension. Whenever a study is designed to turn a spotlight on a special population, the light is also shed on the mainstream from which the target deviates.

Buch. Condizione: Neu. Neuware - Acronycine, a potent antitumor agent, was discovered in the bark of the small Australian Rutaceous tree, Acronychia baueri Schott. This new work presents a comprehensive survey of the isolation, structure determination, methods of synthesis, and the biological properties of acronycine, as well as an account of natural and synthetic analogues of acronycine, and their biological properties.Solanum alkaloids were reviewed in 1990 and this book surveys the new developments (isolation procedures, structural elucidation methods) and critically updates earlier reviews. In addition it presents the interesting chemistry and synthesis of cyclopeptide alkaloids. These cyclopeptide alkaloids have been isolated from ascidians, sea hares, and cyanobacteria. Also included are reviews of the use of the functionalized lactam, pyroglutamic acid, as a chiral template for the synthesis of alkaloids. The second review examines the on-line coupling of capillary electrophoresis (CE) and mass spectrometry (MS) for the analysis of alkaloid mixtures. Finally a review of oxygenated analogs of the alkaloid Marcfortine for their potent antiparasitic activity is included at the end of this work. Each chapter in this volume has been reviewed by at least one expert in the field. Indexes for both subjects and organisms are provided.

Buch. Condizione: Neu. Neuware - This book takes as a starting point, John Dewey's article, The Reflex Arc Concept in Psychology, in which Dewey was calling for, in short, the utilisation of systems theories within psychology, theories of behaviour that capture its nature as a vastly-complex dynamic coordination of nested coordinations. This line of research was neglected as American psychology migrated towards behaviourism, where perception came to be thought of as being both a neural response to an external stimulus and a mediating neural stimulus leading to, or causing a muscular response. As such, perception becomes a question of how it is the perceiver creates neural representations of the physical world. Gestalt psychology, on the other hand, focused on perception itself, utilising the term Phenomenological Field; a term that elegantly nests perception and the organism within their respective, as well as relative, levels of organisation. With the development of servo-mechanisms during the second world war, systems theory began to take on momentum within psychology, and then in the 1970s William T Powers brought the notion of servo-control to perception in his book, Behavior: The Control of Perception. Since then, scientists have come to see nature not as linear chain of contingent cause-effect relationships, but rather, as a non linear, unpredictable nesting of self referential, emergent coordinations, best described as Chaos theory. The implications for perception are astounding, while maintaining the double-aspect nature of perception espoused by the Gestalt psychologists. In short, system theories model perception within the context of a functioning organism, so that objects of experience come to be seen as scale-dependent, psychophysically-neutral, phenomenological transformations of energy structures, the dynamics of which are the result of evolution, and therefore, a priori to the individual case. This a priori, homological unity among brain perception and world is revealed through the use of systems theories and represents the thrust of this book. All the authors are applying some sort of systems theory to the psychology of perception. However, unlike Dewey we have close to a century of technology we can bring to bear upon the issue. This book should be seen as a collection of such efforts.