During the past decade we have witnessed not only an increase in knowledge of the "traditional" biophysical problems, but also an understanding of the molecular basis of various biological phenomena. The principles and methods of biophysics now provide an underpin ning of all of the basic biosciences and are the rational language for discussion between scientists of different disciplines. The International School on Biophysics Supramolecular Structure and Function held in Dubrovnik in September 1984 had as its goal to provide comprehensive discussions on a large number of subjects both for younger scientists at the doctoral or postdoctoral level interested in the molecular nature of fundamental biological entities, and for experienced scientists wishing to gain a broader insight into molecular structures and functions. The topics discussed at the School were inter- and intramolecular interactions in biological systems, and the structure, organization, and function of biological macromolecules and supramolecular assemblies. A number of topics were centered around either a biological problem or a physical technique, sometimes giving an unbalanced view of the field under discussion. Some of the topics required previous knowledge of basic biophysical principles, which were then applied to gain greater insight into the molecular functions of diverse supramolecular systems. Although not all the lectures could be prepared for publication in this volume, I hope that it contains valuable up-to-date information on various aspects of the molecular basis of life."

For centuries man knew about the lightning of the sky (atmospheric or physical electricity) and the numbing effects from contact with powerful electric fishes (animal electricity). Then, after proper experimentation and a synthetic ration ale, it began to appear that physical and animal electricity were related in fundamental respects. This realization was made at the end of the eighteenth century, since when the pages of history have been replete with exciting dis coveries and developments in electricity and magnetism, electrochemistry, and electrophysiology. It is hoped that this manual will enable some students to relive some of that excitement. The author remembers vividly the excitement when, as an undergraduate, he saw his first action potential. This book is not intended for any particular group of students; it should prove to be of some value to students in secondary schools, colleges, and gradu ate schools. Based on personal experience, the author feels that many teachers will also find it of use. Nor is the manual intended solely as a laboratory manual for an introductory course in neurophysiology. Some of the experiments might be introduced into the formallaboratory schedule of general or animal physiology courses. Alternatively, the various experiments might provide the bases for the beginning of special projects lasting for a full semester or even longer."

Recent improvements in the performance of light sources, i.e. reduction in pulse length and increases in wavelength range and power levels, have led to ultrafast technology becoming a basic tool in a wide variety of scientific fields. This book describes the remarkable technological improvements and results of new applications in the natural sciences and various engineering fields.

A sound knowledge of biology, mathematics, physics and chemistry in needed to understand how excitable cells function and the many basic concepts involved in acquiring this knowledge are described from first principles in this book. As these principles equally apply to other biological fields such as the study of membrane transport, artificial membranes, signal capturing, analysis in biological systems and general applications of mathematics and physics to biology, they are of general interest. An important feature of the book is the appendices, in which mathematical functions are derived, and which ensure the usefulness of the volume as a reference manual.

In the continuing quest to explore structure and to relate struc tural organization to functional significance, the scientist has developed a vast array of microscopes. The scanning electron microscope (SEM) represents a recent and important advance in the development of useful tools for investigating the structural organization of matter. Recent progress in both technology and methodology has resulted in numerous biological publications in which the SEM has been utilized exclusively or in connection with other types of microscopes to reveal surface as well as intracellular details in plant and animal tissues and organs. Because of the resolution and depth of focus presented in the SEM photograph when compared, for example, with that in the light microscope photographs, images recorded with the SEM have widely circulated in newspapers, periodicals and scientific journals in recent times. Considering the utility and present status of scanning electron microscopy, it seemed to us to be a particularly appropriate time to assemble a text-atlas dealing with biological applications of scanning electron microscopy so that such information might be presented to the student and to others not yet familiar with its capabilities in teaching and research. The major goal of this book, therefore, has been to assemble material that would be useful to those students beginning their study of botany or zoo logy, as well as to beginning medical students and students in advanced biology courses.

Activation by and desensitization to signals originating from the environment is common in all organisms, ranging from prokaryotes to higher eukaryotes. Recently, a number of novel mechanisms involved in activation and desensitization have been elucidated. The similarities of the molecular mechanisms of activation and desensitization in the various systems are striking. In the first book (1987) on this topic, the functional and structural similarities of the various mechanisms to attenuate the effect of an outward signal were emphasized. Justification to have a second book three years later is the explosive growth of information in the field. More components involved in signal transfer have been discovered and also that several more G-proteins appear to play a role during this process. The interest in signal attenuation concurs with these developments. The emphasis in this book is on the common signal transfer elements responsible for activation and desensitization in animals, plants and microorganisms.

6 Ions can pass through a single membrane channel at a rate of 10 ions/second. Over the last decade the ability to measure ion flux so precisely and to document the opening and closing of individual ion channels has provided a powerful tool to those working on smooth muscle physiology and vascular reactivity. The use of potassium channel blockers by Tom Lloyd in the 1960s and calcium channel blockers by Ivan McMurtry in the 1970s indicated the importance of ion flux in regulating pulmonary vascular tone. Recent advances in technology. principally the patch-clamp technique and fluorescent ion-sensitive dyes. now permit a more detailed description of physiologic mechanisms. This volume arises from the Sixth Grover Conference on the Pulmonary Circulation. a NATO Advanced Research Workshop. held in Colorado in October 1992. A group of international sCientists who are leaders in the field of ion flux focused their attention on the problems of the pulmonary vasculature. The chapters in this book describe the present state of knowledge of the movement and storage of ions in vascular endothelial and smooth muscle cells. Those who are not familiar with the techniques of patch clamping and calcium imaging will find an introduction to these methods in the chapters by Leblanc and Wan and Archer et al. The role of potassium channels in oxygen sensing illustrates the rapid progress which the study of ion currents has made possible.

Chemical Biophysics provides an engineering-based approach to biochemical system analysis for graduate-level courses on systems biology, computational bioengineering and molecular biophysics. It is the first textbook to apply rigorous physical chemistry principles to mathematical and computational modeling of biochemical systems for an interdisciplinary audience. The book is structured to show the student the basic biophysical concepts before applying this theory to computational modeling and analysis, building up to advanced topics and research. Topics explored include the kinetics of nonequilibrium open biological systems, enzyme mediated reactions, metabolic networks, biological transport processes, large-scale biochemical networks and stochastic processes in biochemical systems. End-of-chapter exercises range from confidence-building calculations to computational simulation projects.

Here for the first time in one book is a comprehensive and systematic approach to the dynamic modeling and control of biped locomotion robots. A survey is included of various approaches to the control of biped robots, and a new approach to the control of biped systems based on a complete dynamic model is presented in detail. The stability of complete biped system is presented for the first time as a highly nonlinear dynamic system. Also included is new software for the synthesis of a dynamically stable walk for arbitrary biped systems, presented here for the first time. A survey of various realizations of biped systems and numerous numerical examples are given. The reader is given a deep insight into the entire area of biped locomotion. The book covers all relevant approaches to the subject and gives the most complete account to date of dynamic modeling, control and realizations of biped systems.

The objective of this book is to make analytical methods available to students of ecology. The text deals with concepts of energy exchange, gas exchange, and chemical kinetics involving the interactions of plants and animals with their environments. The first four chapters are designed to show the applications of biophysical ecology in a preliminary, sim plified manner. Chapters 5-10, treating the topics of radiation, convec tion, conduction, and evaporation, are concerned with the physical environment. The spectral properties of radiation and matter are thoroughly described, as well as the geometrical, instantaneous, daily, and annual amounts of both shortwave and longwave radiation. Later chapters give the more elaborate analytical methods necessary for the study of photosynthesis in plants and energy budgets in animals. The final chapter describes the temperature responses of plants and animals. The discipline of biophysical ecology is rapidly growing, and some important topics and references are not included due to limitations of space, cost, and time. The methodology of some aspects of ecology is illustrated by the subject matter of this book. It is hoped that future students of the subject will carry it far beyond its present status. Ideas for advancing the subject matter of biophysical ecology exceed individual capacities for effort, and even today, many investigators in ecology are studying subjects for which they are inadequately prepared. The potential of modern science, in the minds and hands of skilled investigators, to of the interactions of organisms with their advance our understanding environment is enormous."

Structural biology is undergoing a revolution in both the sophistication of new biophysical methods and the complexity of problems in biomolecular structure and organization opened up for study. These changes are directly attributable to major advances in computer technology, computational methods, development of high intensity synchrotron radiation sources, new magnetic resonance methods, laser optical techniques, etc. Structure-function problems previously considered intractable may now be solved. As this area of specialisation continues to expand, there is a need to review the various physical methods currently being used and developed in struc tural molecular biology. At the same time that individual techniques and their applications become more specialized, the need for effect ive communication between investigators gains in imperative. It is vital to forge links among sub-disciplines and to emphasise the complementary nature of results observed by different biophysical methods. This publication contains the review lectures given at a meeting on "Current Methods in Structural Molecular Biology" spon sored by NATO as an Advanced Study Institute and by FEBS s Advanced Course No. 78. The aim of the meeting was to bring together, in a teaching environment, students and specialists in diverse biophysical methodologies with the specific purpose of exploring, questioning and critically assessing the present and future state of biological structure research. The scientific content of the interdisciplinary Study Institute centred around three interrelated aspects; biophysical methods and instrumentation, their application to biological structure problems, and derivation of structural information and insights."

In July 1989 a symposium was held at the Physiology Department of the Georg August University, G6ttingen, on the physiological, biophysical, biochemical, and technical principles of the coding of chemical substances both in nervous systems and artificial devices. This book is the collection of the papers presented at that meeting. Biological and artificial systems for odor coding both have in common that the stimulus selectivity of the receptor cells (sensors) is usually very poor, and the mechanisms which determine selectivity and sensitivity are largely unknown. However, a poor selectivity allows the coding of an enormous number of stimuli by combinations of receptor activities. In the field of chemosensory information coding there are thus two major problems: the function of the receptors and the network that processes and evaluates the primary information of the sensors. Accordingly, this volume has three parts: sensors, the network following the sensors, and the coding in this network. The expert secretarial assistance of M. Holtmann in preparing the camera-ready manuscript is gratefully acknowledged. D. Schild G6ttingen, August 1989 CONTENTS l. Response of olfactory receptor cells, isolated and in situ, to low concentrations of odorants 1 Stephan Frings, Bernd Lindemann 2. Excitation and adaptation of frog olfactory receptor neurones upon stimulation with second messengers and natural odorants 9 D. Schild, J. A. DeSimone, S. Hellwig 3. Receptor selectivity and dimensionality of odours at the stage of the olfactory receptor cells 21 GiJJes Sicard 4.

Ambiguity in Mind and Nature is the result of cognitive multistability, the phenomenon in which an unchanging stimulus, usually visual, gives rise in the subject to an oscillating perceptual interpretation. The vase/face picture is one of the most famous examples.
In this book scientists from many disciplines including physics, biology, psychology, maths and computer science, present recent progress in this fascinating area of cognitive science. Using the phenomenon of multistability as a paradigm they seek to understand how meaning originates in the brain as a consequence of cognitive processes. New advances are achieved by applying concepts such as self-organization, chaos theory and complex systems to the latest results of psychological and neurophysical experiments.

In our daily lives we conceive of our surroundings as an objectively given reality. The world is perceived through our senses, and ~hese provide us, so we believe, with a faithful image of the world. But occ~ipnally we are forced to realize that our senses deceive us, e. g. , by illusions. For a while it was believed that the sensation of color is directly r~lated to the frequency of light waves, until E. Land (the inventor of the polaroid camera) showed in detailed experiments that our perception of, say, a colored spot depends on the colors of its surrounding. On the other hand, we may experience hallucinations or dreams as real. Quite evidently, the relationship between the "world" and our "brain" is intricate. Another strange problem is the way in which we perceive time or the "Now". Psychophysical experiments tell us that the psychological "Now" is an extended period of time in the sense of physics. The situation was made still more puzzling when, in the nineteen-twenties, Heisenberg and others realized that, by observing processes in the microscopic world of electrons and other elementary particles, we strongly interfere with that world. The outcome of experiments - at least in general - can only be predicted statistically. What is the nature ofthis strange relationship between "object" and "observer"? This is another crucial problem of the inside-outside or endo-exo dichotomy.

"Mr. Wolkenstein's Physical Approaches to Biological Evolution, whether or not it proves to give the ultimate truth on the matters with which it deals, certainly deserves, by its breadth and scope and profundity, to be considered an impor tant event in the philosophical world." This is a quotation from an introduction written by Bertrand Russell for Ludwig Wittgenstein's Tractatus Logico-Philosophicus. I exchanged only name and subject. As for the rest, I could continue quoting Russell, but I would rather say something myself. As Wittgenstein did with formal logic, Wolkenstein rectifies our views on how to approach the logic of life from a formal theoretical basis. Many bio logists do not believe that their subject lends itself to the scrutiny of physical theory. They certainly admit that one can simulate biological phenomena by models that can be expressed in a mathematical form. However, they do not believe that biology can be given a theoretical foundation that is defined within the general framework of physics. Rather, they insist on a holistic approach, banning any reduction to fundamental principles subject to physical theory."

For a long time, immunology has been dominated by the idea of a simple linear cause-effect relationship between the exposure to an antigen and the production of specific antibodies against that antigen. Clonal selection was the name of the theory based on this idea and it has provided the main concepts to account for the known features of the immune response. More recently, immunologists have discovered a wealth of new facts, in the form of different regulatory cells (helpers, suppressors, antigen presenting cells), genetic determinations of immune responses such as those involved in graft re jections, different molecular structures responsible for intercellular interactions such as interleukins, cytokins, idiotype-antiidiotype recognition and others. While furthering our understanding of the local interactions (molecular and cellular) in volved in the immune response, these discoveries have led to a questioning of the simplicities of the classical clonal selection theory. It is clear today that every single immune response is a cooperative phenomenon involving several different molecular and cellular interactions taking place in a coupled manner. In addition, cross reactivity to different antigens has shown that responses of the whole im mune system to different antigens are not completely isolated from one another and that the history of encounters with different antigens plays a crucial role in the maturation of the whole system. Thus, problems of complexity, generation of di versity and self-organization have entered the field of immunology.

Adaptation to altitude hypoxia is characterized by a variety offunctional changes which collectively facilitate oxygen trans port from the ambient medium to the cells of the body. All of these changes can be seen at one time or another in the course of hypoxic exposure. Yet, as already stressed (Hannon and Vogel, 1977), an examination of the literature gives only a sketchy and often conflicting picture of the exact nature of these changes and how they interact as a function of exposure duration. This is partly because of the limited number of variables explored in a given study, but it is also attributable to differences in experimental design, differences among species in susceptibility to hypoxia, nonstandardized experimental conditions, lack of proper control of physical (e. g. , temperature) and physiological variables (e. g. , body mass), failure to take measurements at key periods of exposure, and gaps in knowledge about some fundamental mechanisms. Furthermore the available data on animals native to high altitude are meager and/or inconclusive. Extensive further work under well-controlled experimental conditions is required before a detailed picture can be made. Nevertheless, it has been a guiding principle in the prepara tion of this monograph rather to summarize the vastly dis persed material that constitutes the comparative physiology of adaptation to high altitude into a coherent picture, than to provide a comprehensive survey of the field.

Review articles by leading scientists in their fields are brought together in this volume to provide a comprehensive treatment of photoacoustic, photothermal and photochemical processes at surfaces and in thin films. The articles introduce the fields, review present knowledge and conclude with latest developments and future prospects. Topics covered include laser-induced desorption, ablation and surface damage; surface acoustic waves; photothermal and photoacoustic characterization of thin films and interfaces; depth profiling in the frequency and time domains; remote testing and nondestructive evaluation; materials characterization; and new theoretical approaches using fractals. The book will interest newcomers to photoacoustics, since it gives an overview of current research and details of experimental methods. It will also be a source of information for those already in the field due to its clear presentation of theory and experimental results. All relevant literature references in this rapidly expanding field are included.

According to its definition, synergetics is concerned with the cooperation of indi vidual parts of a system that produces macroscopic temporal, spatial or functional structures. A good deal of the volumes published within this series dealt with the formation of truly macroscopic structures which we can s. ee with our eyes. A common scheme could be developed to understand the formation of many patterns through self-organization. In particular, we have to use concepts which go beyond conventio nal thermodynamics. New ideas became crucial. We have to study kinetic processes, and often few highly excited degrees of freedom play the decisive role in the evo lution of structures. Over the past years it has turned out that quite similar lines of approach apply to a world which at first sight would be classified as "microsco pic." That world consists of processes in which biomolecules are involved. An impor tant example for the problems occurring there is provided by Manfred Eigen's theory of evolution of life at the molecular level (cf. his contribution to Volume 17 of this series). Another important example has been provided by Blumenfeld's book on problems of biological physics (Vol. 7 of this series). There it was proposed to treat biological molecules as machines which, in a certain sense, work through "macros copic" degrees of freedom."

The analysis of neurophysiological brain function is a highly interdisciplinary field of research. In addition to the traditional areas of psychology and neurobiology, various other scientific disciplines, such as physics, mathematics, computer science, and engineering, are involved. The book reviews a wide spectrum of model-based analyses of neurophysiological brain function. In the first part, physical and physiological models and synergetic concepts are presented. The second part focuses on analysis methods and their applications to EEG/MEG data sets. It reviews methods of source localization, the investigation of synchronization processes, and spatio-temporal modeling based on dynamical systems theory. The book includes contributions by well-known scientists such as Hermann Haken, Scott Kelso and Paul Nunez, among others. It is written for students and scientists from all the above-mentioned fields.

This monograph is the result of a course given to graduate students and to the faculty of the Dept. of Medical Physics and Biophysics of Nijmegen University, Nijmegen, The Netherlands, in the fall of 1984 and 1985. The course was intended to put together experi ment, theory, and analysis methods in order to study neural in teraction and coding in the brain. The following pages give a survey of neural interaction and its experimental substrate: cor related neural activity. The basic reason for restricting myself to vertebrate brains was to keep the material concise. As the text developed, however, it became more of a review, than a research monograph, in the attempt to balance theoretical and experimen tal aspects in brain research. Consequently, the book can be read from various points of view: that of requiring an overview of theories and theoretical principles, or an overview of experimental studies in neural interaction and the methods that can be used, or with the conviction that theory and experiment cannot be separat ed. In the latter case the book should be read from beginning to end. A way to read through the theoretical sections and the ex perimental sections of the book is presented in the following flow chart; Theory: /Chap. 2 -Chap. 4 -Chap. 5 ___ ~ Introduction -+ Chap. 1 \, Chap. 10 -+ Chap. 14 Experim~Chap. 3 -Chap. 6 -Chap. 7 -Chap. 8 ~ Chap.

The editors are pleased to present these Proceedings of the V Course of the "International School of Radiation Damage and Pro- tection" of the "E. Majorana Centre", held in Erice (Italy) in No- vember 1983. The lectures and discussions among leading scientists in various disciplines of physics, engineering, biophysics, cellular biology, physiology and medicine from 11 countries are included in this compilation. In this volume we have attempted to explore all aspects of the interaction of static and Extremely Low Frequency (ELF: 0-300 Hz) electric and magnetic fields with biological tissue, systems and whole organisms; we considered dosimetry and what is known or pre- sumed concerning basic interactions, responses from the cellular and molecular level to the whole organism. Discussions of medical appli- cations as well as epidemiologic investigations related to high volt- age transmission were held with critiques of methodologies used and recommendations for future approaches. Consideration was also given to the necessity and principles of setting protection standards for man and the environment. We believe this is the first attempt to put all this informa- tion together into one volume to provide perspective for understand- ing the influence of static and ELF electric and magnetic fields on biological systems. We hope our attempts were successful. Martino Grandolfo Sol M. Michaelson Alessandro Rindi v ACKNOWLEDGEMENTS This is the Fifth Course of the International School of Radia- tion Damage and Protection of the "Ettore Majorana" Centre for Sci- entific Culture directed by Professor A. Zichichi.

The field of capillary-tissue exchange physiology has been galvanized twice in the past 25 years. A 1969 conference at the National Academy of Sciences in Copenhagen resulted in the book Capillary Permeability: The Transfer of Mole cules and Ions Between the Capillary Blood and the Tissue (Crone and Lassen, 1970). It focused on the physiochemical aspects of transcapillary water and solute transport. The field has matured considerably since. This volume was designed as the successor to the 1970 book, and was created at a gathering of the authors at McGill University. It too captures the breadth of a field that has been dramatically enriched by numerous technical and conceptual advances. In 1970 it was already known that the capillary wall was not merely a "cellophane bag" exerting steric hindrances on solute particles. Instead, the endothelial surface was recognized as the site of binding reactions and permeation by passive or carrier-mediated trans port. Furthermore, the cells of the blood could traverse evanescent wide openings in the "zippered" clefts. Today, research priorities have turned more to cell-cell interactions, toward understanding the utility of the gap junctional connections between endothelial cells and neighboring smooth muscle cells, neuronal twigs, and the parenchymal cells of organs. New discoveries in the past few years have revealed the critical importance of the close relationships between the endothelial cells and the parenchymal cells."

Ecological Microcosms is a seminal work which reviews the expanding field of enclosed ecosystem research, and relates the results and models of microcosm studies to general concepts in ecology. Microcosms are miniaturized pieces of our biosphere, ranging from streams and lakes to terraria, agroecosystems, and waste systems. The study of these simplified ecosystems is providing provocative insights into ecological principles as well as issues of environmental management and global stability. The authors have used the well-known thermodynamic approach of H.T. Odum and numerous computer simulations. The book also includes an evaluation of alternative mesocosm approaches for the support of humans in space, as well as appendices to aid in the teaching of environmental concepts using student-created microcosms. Ecological Microcosms will be of interest to ecologists, environmental engineers, policy makers and environmental managers, space scientists, and educators. Robert J. Beyers is a Professor of Biology at the University of South Alabama. Howard T. Odum is Graduate Research Professor of Environmental Engineering Sciences at the University of Florida, and was awarded, with Eugene Odum, the 1987 Crafoord Prize in the Biosciences.

Nuclear magnetic resonance (NMR) is having an enormous liTIpact on biomedical research both at the basic science and clinical levels. In order to appreciate the elegance and power of this technology a historical perspective is in order. In 1924 Pauli suggested that hydrogen nuclei might possess a magnetic IIlOlllent. This was in fact confinned by Rabbi in 1939 who demonstrated that a beam of hydrogen molecules in the presence of a magnetic field could be mutated by radio frequency fields resonating at the Iarmor frequency. 'Ihe first successful NMR experiments in condensed matter were independently conducted in late 1945 by Purcell, Torrey and PoUnd and by Bloch, Hansen and Packard. 'Ihe Purcell group detected proton NMR in solid paraffin and the Bloch group detected proton in liquid water. Bloch and Purcell received the Nobel Prize in physics in 1952 for these observations . Until about 1952, studies of liquids and solids with broad resonance lines dominated the field of NMR. However, the reports of 3 1 P NMR chemical shifts in several corrpounds in 1949 by Khight, of 14 N resonances in several ions by Proctor and Yu in 1950, and of 1 9 F resonances in several corrpounds in 1950 by Dickinson led to the development of high resolution NMR in Itquids. since the molecular motions in liquids result in very narrow lines compared to those in solids, :much smaller chemical shifts could be detected.