elsevier bv dez 1999 (4 risultati)

Buch. Condizione: Neu. Neuware - During the past several years there has been a shortage of flight opportunities for biological and medical projects. And those that were available usually had severe restrictions on instrumentation, number of subjects, duration, time allotted for performing the experiments, a possibility for repetition of experiments. It is our hope and expectation that this will change once the international Space Station is in full operation. The advantages of a permanent space station, already demonstrated by the Russian Mir station, are continuous availability of expert crew and a wide range of equipment, possibility of long-term experiments where this is waranted, increased numbers of subjects through larger laboratory space, proper controls in the large 1-G centrifuge, easier repeatability of experiments when needed.The limited number of flight opportunities during recent years probably explains why it has taken so long to acquire a sufficient number of high quality contributions for this seventh volume of Advances in Space Biology and Medicine. While initially the series wassailed at annually appearing volumes, we are now down to a biannual appearance. Hopefully, it will be possible to return to annual volumes in the future when results from space station experimentation at beginning to pour in.The first three chapters of this volume deal with muscle. Fejtek and Wassersug provide a survey of all studies on muscle of rodents flown in space, and include an interesting demography of this aspect of space research. Riley reviews our current knowledge of the effects of long-term spaceflight and re-entry on skeletal muscle, and considers the questions still to be answered before we can be satisfied that long-term space missions, such as on the space station, can be safely undertaken. Stein reviews our understanding of the nutritional and hormonal aspects of muscle loss in spaceflight, and concludes that the protein loss in space could be deleterious to health during flight and after return. Strollo summarizes our understanding of the major endocrine systems on the ground, then considers what we know about their functioning in space, concluding that there is much to be learned about the changes taking place during spaceflight. The many problems of providing life support (oxygen regeneration and food supply) during extended stay on the Moon, on Mars, or in space by means of plant cultivation are discussed by Salisbury. The challenges of utilizing electrophoresis in microgravity for the separation of cells and proteins are illustrated and explained by Bauer and colleagues. Finally, the chapter on teaching of space life sciences by Schmitt shows that this field of science has come of age, but also that its multidisciplinary character poses interesting challenges to teaching it.

Buch. Condizione: Neu. Neuware - Peptidomimetics have found wide application as bioavailable, and often potent mimetics of natural peptides. They form the basis of important classes of enzyme inhibitors, they act as receptor agonists and antagonists, and they have even been used to mimic DNA structure. Recent advances in the use of solid-phase organic synthesis have paved the way for the preparation of libraries of these structures to allow the rapid optimization of theri biological properties and hence therapeutic potential. We are also beginning to gain a greater understanding of the structural features of this class of compounds that influence their ability to permeate membranes, and their rate of clearance and metabolism. This volume brings together many of these critical issues by highlighting recent advances in a number of core peptidomimetic-based research.

Buch. Condizione: Neu. Neuware - In this book, fifteen authors from a wide spectrum of disciplines (ranging from the natural sciences to the arts) offer assessments of the way time enters their work, the definition and uses of time that have proved most productive or problematic, and the lessons their subjects can offer for our understanding of time beyond the classroom and laboratory walls. The authors have tried, without sacrificing analytical rigour, to make their contribution accessible to a cross-disciplinary readership.Each chapter reviews time's past and present application in its respective field, considers the practical and logical problems that remain, and assesses the methods researchers are using to escape or resolve them. Particular attention is paid to ways in which the technical treatment of time, for problem-solving and model-building around specific phenomena, call on - or clash with - our intuitive perceptions of what time is and does. The spans of time considered range from the fractions of seconds it takes unstable particles to disintegrate to the millions of years required for one species to give way to another. Like all central conceptual words, time is understood on several levels. By inviting input from a broad range of disciplines, the book aims to provide a fuller understanding of those levels, and of the common ground that lurks at their base. Much agreement emerges - not only on the nature of the problems time presents to modern intellectual thought, but also on the clues that recent discoveries may offer towards possible solutions.

Buch. Condizione: Neu. Neuware - The Second Sino-US Symposium Workshop on Recent Advancement of Computational Mechanics in Structural Engineering was held between May 25-28, 1998, in Dalian, China. The objectives were: to share the insights and experiences gained from recent developments in theory and practice; to assess the current state of knowledge in various topic areas of mechanics and computational methods and to identify joint research opportunities; to stimulate future cooperative research and to develop joint efforts in subjects of common needs and interests; to build and to strengthen the long-term bilateral scientific relationship between academic and professional practicing communities.Topics discussed covered the entire field of computational structural mechanics. These topics have advanced broad applications in the engineering practice of modern structural analysis, design and construction of buildings and other structures, and in natural hazard mitigation.