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Book reviews

The Annals o f Biomedical Engineering has initiated a book review series under its newly formed section dedicated to Professional Technical Service. The book review section will bring timely and informative reviews of new books in biomedical engineering to our readers. Additional book reviewers are needed to support this effort. If you would be willing to write an occasional review in exchange for a copy of the book, please send your name, address, phone number and areas of interest to:

Professor R. McNeil Alexander is a zoologist who, over the last few decades, has clearly been a pioneer in the area of animal mechanics, especially in regard to how mechanical principles relate to tasks performed by various animals. In this delightful book he provides us with a wealth of insights that are based both on his practical experience as an astute observer of animals in motion and on his work in formal research. However, as mentioned in the preface, this book is directed primarily toward those in the biological sciences rather than bioengineers.
Chapter 1 provides the basic mathematical backbone for the book, defining: elasticity in terms of stress and strain; how elastic energy can be stored and retrieved; viscous losses; and the concept of tissue mechanical properties being time-and frequency-dependent. For the engineer, most of this will be a review. The sections on molecular mechanisms and muscle elasticity are informative reviews of basic knowledge necessary for full understanding of subsequent chapters.
The short chapter entitled "Springs and muscle antagonists" goes over three straightforward examples of uses for passive springs that work to oppose muscles 317 and/or gravity: ligaments of bivalve mollusc shells; the ligamentum nuchae (which serves as a tension band helping to hold up the head of various hoofed mammals); and elastic tissue within sea anemones (which, working antagonistically with muscles, allows incredible changes in the shapes of these animals). This chapter is followed by one on "Springs as energy stores: running," which develops the "bouncing ball" principle and then presents a number of examples including: running in humans (both a macro-analysis suggesting significant stored energy and an analysis of the arch of the foot as one of the "springs" responsible for this effect); hopping in kangaroos; and hoofed mammals trotting and galloping (where different mechanisms are suggested for these two cases). Interspersed is the development of a simple spring-mass-gravity model. Chapter 4 addresses the use of springs in swimming and flight. The first part of the chapter develops a number of concepts including: hydrodynamic work; the effects of series and parallel arrangements of springs; and how an "optimum" stiffness can depend on the system mass/inertia, the frequency of oscillation, and the structural location of the spring. The examples of hovering insects, insects in flight, and whales are interesting, although proof of spring mechanisms appear weaker in this chapter due to the limited availability of quantitative experimental data. A side note is that Professor Alexander treats elastic mechanisms as having linear (Hookean) properties. As an example, to explain the "clicking" mechanism of some flies, he proposes both compression and tension springs rather than a nonlinear spring with traditional concave upward load-extension properties.
Chapter 5 covers examples of elastic recoil in fibre-wound animals such as worms, certain fish, and whales. A helical type of weave is assumed in the mathematical development. The conceptual foundation lies in the assumption that bending of the animal causes elastic energy storage within fibers to change. Interestingly, model predictions are a dramatic function of boundary conditions, and in particular, whether or not the fibers attach to spines at two diametrically opposed locations along the long axis. For example, if they do (as might be true of certain fish), then the determination of which side of the body increases in stored elastic energy and which side decreases (and whether or not the animal becomes longer and thinner during oscillatory movements) depends on the angle of the helical weave, with fibers at 55-60 deg (relative to the long axis) being the neutral case of minimal storage.
Chapter 6, "Springs as catapults," uses locust jumping to show how a slowly contracting, powerful muscle can be the prime mover for a fast, explosive jump. During initial extensor contraction the leg is highly flexed, causing a low extensor moment arm and a high moment arm for the relatively weak flexor which is also contracting. With increased contraction, an amount of elastic energy sufficient for the jump is stored both within the extensor tendon and within the joint due to its elastic compression. When stimulation of both muscles ends, the flexor is able to relax more quickly, thus serving as the catapult that releases the stored energy-another fascinating example of the beneficial use of springs.
Chapter 7 on "Suspension springs and shock absorbers" starts by developing the framework for damped spring-dashpot-mass systems using the automobile as an example. Examples include a person carrying a weight on the head, paw pads on animals, vibration frequencies in the human skeleton, and breathing while running. To me personally, this chapter was somewhat disappointing since the role of muscles as active elements was not considered. However, the chapter was also one of the few occasions in which Professor Alexander acknowledged the possible value of a non-Hookean spring, where stiffness increases with force (as tends to be true for biological soft connective tissues (e.g. Fung, Am. J. Physiol., 213: 1532-1544, 1967).
The next chapter, "Springs and control," introduces the important question of how musculotendonous properties may affect strategies for the control of movement. Professor Alexander concentrates on the human hand and in particular on the frequency response work of Rack and Ross (J. Physiol., 241: 99-110, 1984) involving the thumb, which provides a worthwhile example. He also develops a simple muscle model and delayed length feedback due to spindle activity. At the end of this short chapter, there are two short paragraphs suggesting how variation in tendon stiffness with force may serve useful purposes for a control system and how cocontraction of antagonistic muscles might be an effective mechanism for stiffness variation. From the point of view of a bioengineer involved in neuromuscular control systems research, this scant coverage was disappointing. There was no mention of any of the recent work in movement control or robotics regarding stiffness regulation or impedance modulation. Professor Alexander may have missed an opportunity here to make a strong case for one of the most important uses of elasticity in animals and humans. However, given the audience that he was addressing, perhaps this book was not the appropriate medium.
The book concludes with a chapter entitled "Springs and size" which includes a nice development of the concepts of elastic and dynamic similarity and how they apply to scaling of body size, etc.--this is Professor Alexander at his best.
In summary, this is a very enjoyable book full of insights into animal mechanics that I highly recommend for its educational merit. However, it is not a book that would likely be suitable as a bioengineering textbook; nor, I suggest, was it intended to be. The field of biosensors has seen a considerable increase in research interest and activity during the past few years. This has been accompanied by a large increase in the volume of research literature in this area. This new book, Applied Biosensors, is part of the Butterworths Publishing Biotechnology Series and concerns itself primarily with the application of basic biosensor research in several different technological areas. The editor has elicited contributions from a truly worldwide collection of experts. (Contributions are included from Sweden, France, Israel, Japan, the UK, and the USSR in addition to several US centers). These contributions are organized into eleven chapters covering a wide range of different types and different application areas of biosensors.
The emphasis of the text, as reflected in the title and in most of the content, is application of biosensors to directly measure chemical or physical variables in the medical diagnostics and laboratory or process control areas. This emphasis on application distinguishes this book from some of the other very good recent texts that have been more theoretical or fundamental in their approach. Nevertheless, a large part of this book still deals with some very basic research, and much of the material describes bi-osensors that have yet to reach the stage of practical application, at least in terms of their wide-spread commercial success (e.g., in vivo glucose sensors). This is probably an accurate reflection of the state of development of the field of biosensors overall and should not be viewed as a failure of the text to always live up to its title. To the extent that biosensors have reached practical application, this book does a reasonable job of discussing most of those applications.
The topic areas covered in the various chapters are extremely diverse in terms of the variables measured, the technology that is employed to measure the variable, and the areas of application for the sensors. For example, there are chapters on miniature electrochemical sensors for determining concentrations of chemical analytes of biological interest such as catacholamines, penicillin, urea, glucose, and oxygen. Several chapters, rather than emphasizing a particular analyte, instead cover a particular technological approach to bi0sensing such as ISFETs or bioluminescence. Still other chapters consider biosensors that relate to a particular type of measured or transduced energy (e.g., electromagnetic or mechanical). Finally, there are chapters that deal with specific areas of application of biosensors such as diabetes mellitus or uterine monitoring. Overall, the book covers electromechanical and optical technologies, many different chemical analytes, several different physical variables and energy modalities, invasive and noninvasive approaches, and a considerable range of application areas.
There are both positive and negative aspects to this wide diversity of topic areas and to the different ways in which the contributors chose to organize their chapters. One nice aspect of the book's diversity is that it provides at least some interesting material to almost anyone who has an interest in biosensors of any kind. This diversity might also lead to the book's adoption as a text for a general course in biosensors, although the price would probably put it out of consideration as a textbook at many universities. Some individuals considering purchasing this book might view the diversity in a more negative light, since those with a research or application interest in a specific biosensor area might find only One or two chapters of much interest. The very different organizational approach to the various chapters has led to some overlap in material, such as the discussion of glucose sensors in the chapters on enzyme mem-braneS, ISFETs, and flow injection systems in addition to the major emphasis on this topic in the chapter on biosensors for diabetes. Another example is the discussion of ISFET fabrication techniques in several different chapters on different topics. The minor inconvenience associated with this spreading out of material on a given topic is reduced by the inclusion of a comprehensive index.
This book emphasizes application rather than theory and is timely at this juncture when biosensors are beginning to make their way out of the laboratory and into the "real world" with increasing frequency, The diversity of topics covered should appeal to those with a broad interest in the whole arena of biosensors, and they will probably want a copy for their own library. Those whose interest is confined to a specific biosensor technology or application area will more likely wish to read those particular chapters in a central library copy. Overall, Applied Biosensors is a valuable addition to the literature in this rapidly emerging field.
ROBERT This book is intended for medical practitioners or students desiring to introduce functional electrical stimulation (FES) into their rehabilitation environments (clinics) or as a new area of research. The authors' stated aim is to provide a logical, organized and up-to-date selection of basic knowledge and methodology from FES studies in the rehabilitation of spinal cord injured (SCI) patients.
The book begins with an excellent synopsis of approaches to FES restoration of the walking pattern in paraplegic subjects with complete SCI lesions. The synopsis includes comparisons of energy costs of walking ambulation with FES to alternate methods of functional mobility (i.e., wheelchair, mechanical passive orthoses, and hybrid orthotics for paraplegic subjects).
There is a general review of the basic electrical stimulation parameters and their effects on muscle measures. This precedes a presentation on clinical assessment of spasticity (multiple motor system dysfunctions) and the effect of electrical stimulation on agonist and antagonist muscle spasticity. Knee joint torque requirements for standing and walking are discussed along with various other useful measures.
More than one third of the book deals with restoration of standing and walking in SCI patients. Basic laws of motion, as applied to the biomechanics of standing, are reviewed, and a rigid model is expanded to a segmented structure (model) of the human body during standing. The book includes a section on the selection of patients according to lesion, neurological status and physiological status for functional electrical stimulation.
The latter third of the book describes FES therapeutic programs and FES-assisted programs for patients with incomplete spinal cord injury and gait-training/restoration and FES-assisted walking programs for patients with complete spinal cord injury.
In summary, the book presents an excellent overview of electrical stimulation of muscles in spinal cord injured patients, basic static biomechanics calculations during standing, and various FES therapeutic programs for medical practitioners and life-science students. For most engineers the value of this book is in the physiology and therapeutic programs; however, for the bioengineer it presents basic material generally covered in undergraduate classes. While the book may not serve as a textbook for engineering students, the synopsis of FES, the effects of electrical stimulation on muscle spasticity, and the therapeutic programs described in the latter part of the book would be of interest and of value to the young biomedical researcher. The strength of this publication lies in its presentation of the practical, established, clinical approach in the use of FES in rehabilitation of SCI patients. Just as important are the 341 references which should serve as an excellent starting point for new researchers in the FES rehabilitation area.
This monograph is a collection of nine chapters in the form of reviews dealing with various fundamental and applied problems associated with drug delivery using macromolecular systems or various sorts of molecular assemblies. For the most part, the reviews take a fairly physical approach, dealing with many of the physical chemical phenomena involved in what is a very complex area. The breadth of the contributions should make it useful to chemists, biochemists or engineers working in the general area of drug delivery. While the depth of the coverage varies, the book, for the most part, assumes only a good science or engineering background. Expertise in the area is not necessary for the book to provide a useful level of information about the sorts of vehicles and problems encountered in attempting to devise new systems for drug delivery. The lucid and thorough descriptions of some of the fundamental problems of kinetics and some of the critical descriptions of the state of the art make portions of the book especially valuable for people who are working in related areas or who might have a peripheral interest in drug delivery and are interested in increasing their understanding of the current problems and prospects in this developing area.
The book covers a diverse group of topics. It opens with a chapter dealing mainly with kinetic models of drug delivery systems. This is an especially important chapter and happens to be very well written. It will be useful both as a review for established workers and as an introduction to those new to the area. It is written at a level such that any technically trained person can understand it, and it offers interesting insights and provides a consolidated basis on which further topics can be considered. It is the most mathematical chapter, as would be expected for a chapter dealing with kinetics, but the math is kept to a very understandable level. Chapter 2 likewise is a generalized review. In this chapter, the structures and properties of various polymers which have been used for drug delivery are concisely surveyed. Problems and advantages of the range of polymeric materials used for drug delivery are emphasized. The cited references are reasonably current. This chapter probably has the most synthetic polymer chemistry described in it but is at a level which would be fully understandable to anyone who had a good course in sophomore organic chemistry. Chapter 3 describes various delivery systems applicable for parenteral administration of drugs. Important unresolved questions about targeting are discussed; however, they are not emphasized, and the bulk of the chapter is in the form of a summary of existing methodologies presented in a rather nonjudgmental way.
Chapter 4 provides a well written but brief introduction to the area of liquid crystals. It and the following chapters deal mainly with drug delivery using various sorts of molecular aggregate systems. This particular chapter takes the time to discuss some introductory material for those unfamiliar with the fundamentals of liquid crystals. As was true for the earlier chapters, there is some overlap with other chapters, especially with regard to those immediately following this chapter. However, each chapter was apparently written independently, and there has been no effort to refer readers to subsequent material.
Chapters 5, 6, and 7 deal with multiple water-oil-water emulsions, microemulsions and liposomes respectively. Chapter 8 continues in this vein with a discussion of solubilization and the structure of nucleic acids in reverse micelles. Of these four chapters, only 8 seems out of place in that it is more of a research paper. It contains relatively little information useful to someone not working in that specific area. The other three chapters do provide a good introduction to what aggregate systems there are, how they are prepared, their properties and likely applications and problems.
The last chapter deals with transdermal drug delivery systems and provides a wellwritten conclusion. It adopts a more critical and instructive approach than some of the chapters on aggregate phenomena. The current problems and status of transdermal devices are clearly discussed and some interesting problems are highlighted. Overall, the chapter provides a succinct but clear description of the approaches used for transport of drugs across the skin in terms anyone with a moderate background in science or technology should understand.
Overall, this book was more useful than many collections of reviews of this sort. For the most part, the chapters provided an excellent introduction while including much current chemistry. It is a book which clearly belongs in any credible research library. It would be a valuable reference to someone working in the area of drug delivery or who has an interest in undertaking research in this expanding area. This book contains forty-two chapters or papers that were presented at the first National Conference on Biomechanics (NCB '88), held at the Indian Institute of Technology Delhi, on December 17-19, 1988.
As stated in the Preface, the intent of the book and the conference at which these papers were presented, is to bring together those Indian scientists, engineers and physicians who are actively involved in biomechanics research, and to allow for the exchange of scholarly information. In this regard, I believe the book meets its stated objective.
The chapters cover a wide range of topics with different levels of comprehensiveness and complexity. Some of the chapters are quite impressive with regard to their presentation of the problem of interest and the methods used to investigate that problem. Other chapters, however, are more difficult to digest because of the complexity of the problem being investigated. The grammar is sometimes awkward to read, probably resulting from the author's use of a language other than his native language.
The chapters are not obviously categorized into subtopics, so it is difficult to scan the Table of Contents and get a grasp of the scope of the book. There is also no subject index, so it is not possible to look for individual areas of interest. Chapter topics range from investigations on models and materials for the repair of bone defects and fractures, to ion transport, perfusion, and filtration in tissues, to the evaluation of above-the-knee and other prostheses, and other types of biomechanical analyses.
Several of the chapters deal only casually with biomechanics and attempt to present a brief review of a broad topic area. For example, Chapter 2, "Biomaterials in Urological Practice," quickly covers several different urological biomaterials and applications.
Other chapters are misleading in their titles. Chapter 14, "Erythrocyte Membrane Dynamics," is in reality a two page explanation of a very eloquent experiment that deals with a much more specific topic than the title indicates.
There are other chapters of the book that indeed make it a valuable resource for Indian biomechanists. Chapter 1, "Appropriate Wheel Chairs for the Third World," and Chapter 26, "A Microcomputer-Based Foot Pressure Measurement in Leprosy," deal with unique problems that do not receive as high priority in the 'United States and Europe.
Adding to the diverse nature of the chapters are not only their topics, but also their perspective. There are roughly equal numbers of chapters dealing with either clinical evaluations or mathematical/theoretical models. This type of coverage is enlightening for the reader, but is nearly impossible to comprehend for any single individual. Chapter 5, "Biomechanical Consideration of Distal Transverse Metacarpal Arch to that of Carpal Disintegration," Chapter 21, "Temperature Distribution in Skin with Uniformly Perfused Tumor in Subdermal Tissues," and Chapter 42, "The Pressure-Volume Response of the Cranial and Craniospinal CSF Space in Dogs," are in sharp contrast to numerous chapters that deal solely with mathematical modeling and little with the clinical environment; although, some verification of model predictions is made. Chapter 16, "A Numerical Model for the Oxygen and Carbon Dioxide Transport in the Systemic Capillaries and the Surrounding Tissue," Chapter 17, "On the Behavior of a Small Disturbance in an Arterial Blood Flow," and Chapter 30, "A Theoretical Study of Catheter Probe in Stenosed Arteries," are among those chapters dealing with very complex mathematics. Some of the mathematical expressions are difficult to read because they are hand written.
As a whole, Biomechanics will not be of great value to a large number of investigators, and it is not a text book. It does do a reasonable job of identifying and presenting current research programs in India. Most of these areas are applicable to the international research community as a whole, but not all are. Because of the diversity in terms of the review and clinical, laboratory, and mathematical treatment of research problems presented, all investigators involved in biomechanics research should find some portion of the book valuable. This volume contains the proceedings of the European Congress on Biomaterials organized through the joint collaboration of the Rizzoli Orthopaedic Institute in Bologna and the European Society for Biomaterials. The meeting was held in Bologna, Italy, September 14-17, 1986. During the meeting, 26 keynote and invited lectures and 295 scientific papers were presented. This book contains 125 of these papers and covers a broad range of biomedical research areas. It is divided into seven sections:
Even though the papers published in this series are supposed to be equivalent to journal articles, I found them to be shorter and lacking in detail. In this way the book is similar to proceedings of other meetings. Also, as can be expected with any large collection of articles, the quality fluctuates significantly.
The book gives a good overview of the biomedical research in Europe (there are also papers from the U.S. and Japan). Papers from Italy dominate the book and it was interesting to find out about the large body of biomedical research going on in that country. The German and the Dutch papers were also interesting. In general, the hard tissue papers seemed to have higher quality than the soft tissue work, and the ceramic implant applications, both in orthopaedic and in dental areas, were especially intriguing. On the soft tissue side the contact lens and occular implant papers stood out, whereas the cardiovascular work was disappointing. The final section on standards also did not present any new ideas in this very important and controversial area. The keynote lectures left much to be desired, as they consisted primarily of a rehashing of old ideas.
Since many different areas are covered in this volume, it is very unlikely that the entire book would be of interest to a single scientist. Therefore, the price of $175 is high for personal use. On the other hand, it is a bargain to get the equivalent of one year of several journals for this price, especially for libraries. It is also an excellent tool for keeping track of developments and researchers in Europe. As book review editor I frequently receive unsolicited books from publishers. Some of these are relevant and move directly into our review process. Others are not relevant and are returned, set aside, or otherwise disposed of. The Chitin Sourcebook is an example of a work that arrived unsolicited. A quick look revealed that the origin of this book was the M.I.T. Sea Grant Program. Since, at the time, chitin meant nothing to me, this information was enough for me to put the book aside. Some months later I was reading the literature on resorbable sutures and came across an article suggesting chitin as a suitable source material for this application. This brought me back to the Chitin Sourcebook, and this time I discovered the section on biomedical applications.

FERTAC BILGE
For any readers who may be as ignorant as I was, chitin is a cellulose-related polysaccharide. Chitin, chitin derivatives, and chitin-related enzymes function as structural, protective, and/or scavenger compounds in almost all living organisms. Of special interest to the Sea Grant program is that these compounds occur in the shells of crustaceans and therefore represent an economic potential for industrial applications of this material as harvested from the sea.
The section on biomedical applications has 115 alphabetical index entries ranging from "Activation of macrophages by O-(Carboxymethyl) chitins" to "Wound-healing acceleration, chitin and chitosan." These applications include artificial membranes, thromboresistant materials, controlled release of drugs, burn treatments, vascular grafts, and sutures. These entries cite approximately 50 unique items. About one third of these are selections from the book Chitin in Nature and Technology, Edited by Muzzarelli, Jeuniaux and Goodway (Plenum Press, 1986). Another third are individual journal articles.
The remainder of the book provides some background information (Section I), eleven other application areas (e.g., animal nutrition, fibers and textiles, pharmaceuticals, etc.), and index sections on enzymes, methods of preparation and production, structure and properties, methods of analysis and characterization, and chemicals. There is also an author index and a 534 page bibliography containing 540 references.
This work has general interest in terms of the concept of finding uses for a naturally occurring and potentially economically important material. It is also of possible interest to researchers looking up specific applications, for whom it meets its goal of providing an entry point to the literature. It is a worthwhile research library resource, but probably of only one time value to the biomedical engineer for whom its price would be hard to justify. On another note, it would be an excellent candidate for a PC disk version. The general purpose of this text is to provide an introduction to tactile sensing for the senior or graduate level student. Tactile sensing has become an important issue in robotics for tasks of manipulation and force sensing. These concerns have been seen as a significant obstacle for robotics research in the past. Although the development of autonomous robots has been desired for some time, a significant application of tactile based robots is in the field of telerobotics. The precision and performance of the man/robot interface is crucial in many settings where the robot is remotely controlled by the human operator. The performance of tactile sensing is commonly compared with that of people. As such, it is not surprising that a number of significant tactile issues are pertinent to medicine as well as robotics. This text does an excellent job of relating these issues and combining the strengths and weaknesses of the different technologies when applied to both people and robots.
The primary tone is that of a textbook, with emphasis on instruction of the basic concepts. It is didactic with study questions at the end of each chapter. The references are current and numerous, which provides the reader with a ready source for further inquiry into each area. The book's primary emphasis is in the qualitative aspects of the different sensing technologies rather than detailed modeling and theory. It does, however, provide enough detail and application of tactile sensing technology to be extremely useful as a basic reference handbook. In addition to the various sections describing tactile technology and applications, there is a reference list of tactile sensor manufacturers.
The book is composed of 18 chapters written by eleven authors, all from the Department of Electrical and Computer Engineering at the University of Wisconsin. Although it is an excellent text, the lack of theoretical insight into the different sensor issues may be due to the background of the various authors. It would have been preferable to have authors from other institutions, with focussed strengths, writing their respective chapters.
The introduction does a good job of identifying tactile sensing issues; however, visual sensing is referred to as being "well developed," a rather strong overstatement. The importance of this book is for reliable measurement of forces in robotics and medicine, not merely augmentation of vision technology. Chapters 2 and 3 discuss physiological tactile sensing as well as pathoIogies related to physiological sensing. Somewhat misplaced, Chapter 18 discusses electrotactile stimulation and physiologic response. Chapter 4 addresses deformable materials in relation to human skin as well as robotics. Chapter 5 examines metal strain gaaages" and is the first chapter directly related to force measurement. Chapters 6 thru 12 discuss semiconductor strain gauges, conductive elastomers, carbon fibers, and piezoelectric, inductive, capacitive, and optoelectronic sensors. While some of these chapters are slightly stronger than others, appropriate emphasis is placed on each of the sensing technologies in accordance with its maturity and development. Chapters 13 through 17 address different aspects of tactile sensor application with a greater emphasis placed on medical applications.
In summary, this text should be of value to professionals in several fields, as well as being an excellent instructional text. Any professional concerned with the measurement of force, with emphasis on resolution, would find this text invaluable. The sensor researcher will find this text an excellent instructional tool; however, many professionals who develop tactile sensing technology would likely prefer references of a more theoretical nature.
The need for numerical methods in the biomedical sciences has increased with increasing technology. As newer technologies grow, the problems associated with biological modeling and numerical solution are also growing. The concept of this book provides a distinct service to those in the interdisciplinary field relating math, biology, and technology. Unfortunately, the nature of this text is not didactic; rather, it is strictly targeted to students with rigorous mathematical interests.
The book is composed of nine chapters, each of which discusses the theoretical concepts involved with the methods introduced. Applications toward biological sciences are mentioned; however, solutions and examples are sparse. Although numerical methods is a rather large field of study, the author discusses techniques and methods which are pertinent to biological systems. The chapters and the information in each are ordered in a logical fashion. The varying techniques build, where possible, on concepts previously presented. The organization of the text is its strongest point when compared to other numerical methods books. The first chapter deals with linear algebra where the concepts of vector norms, gradients, and eigenvalues are reviewed and discussed. Chapter 2 deals with interpolation and approximation. Nonlinear equations and nonlinear systems are discussed in Chapter 3. Chapter 4 introduces both differentiation and integration. First and second order equations are discussed in Chapters 5 and 6, respectively. Hyperbolic, parabolic, and elliptic equations are discussed in Chapters 7 through 9, respectively. Each chapter contains pertinent definitions, theorems, lemmas and proofs for mathematical rigor. The problems at the end of each chapter adequately cover the material presented; however, no solutions are provided. In addition to the main body of the text, two appendixes provide supplemental information. Appendix A briefly reviews some essential elements of calculus. Appendix B itemizes applicable routines in the NAG Fortran library. The text is concluded with an excellent, current bibliography for further reference.
This text would be of value in the fields of mathematical modeling, biomathematics, or biostatistics. However, it is not appropriate for most engineers, biologists, or physiologists, even at the graduate level. This volume contains eleven very interesting discussions of diagnostic, thera_peutic, or monitoring systems for medical applications. The descriptions of VLSI systems focuses on the system level use of VLSI components. That is to say, no discussion of schematic design or VLSI layout of a microchip is involved. Most of the systems involve the use of commercially available VLSI devices, even if these devices are custom fit for medical applications. The appropriate audience for this volume would be medical or engineering persons involved in system design of medical electronics, or VLSI designers interested in the current needs and practices of the medical electronics field.
All of the chapters present a self-contained discussion of a specific topic. This includes an introduction and history, a description of the medical or biological functions involved or addressed, and a system or current state-of-the-art description of the VLS[ electronics utilization in the application being discussed. A quick scan of the table of contents would show the interested reader the topics discussed, which include magnetic resonance imaging, neurometric analyzer, ultrasonic imaging, electrocardiography, Holter monitoring, cardiac pacemakers, neural stimulation, infusion pumps, and sensors. In addition, the introduction discusses VLSI trends and design approaches, and the final chapter considers the safety and reliability considerations for VLSI in medicine. This is a very valuable discussion for system designers who have not been involved in medical applications before.
Each chapter does a thorough job of presenting the topic being discussed and giving concrete examples, including parts numbers, of a specific system. Briefly the highlights of some of the unique presentations in each chapter include: * Magnetic Resonance Imaging. Basics of MRI and system requirements and descriptions as well as a perceptive discussion of marketing trends often encountered in VLSI production. 9 Neurometric Analyzer. Description of the need for an entire system for the analyzer, including important user friendly interfaces (graphics) and multi processor architectures. 9 Ultrasonic Imaging. Description of the various modes utilized and information about the market in this area, including a good discussion of opportunities and the future of VLSI in this area. 9 Electrocardiography. Microcomputer based systems and signal processing and whether semicustom or standard design strategies are warranted. 9 Holter monitoring. Requirements of the system and excellent block and component drawings of a system. 9 Pacemakers. Basics of pacemaker design and a discussion on automatic testing (for manufacturers) and packaging considerations. 9 Neural Stimulation. The microcomputer systems involved and the design philosophy used in this area. 9 Infusion pumps. Safety, reliability, and accuracy as well as cost advantages of VLSI based systems. 9 Sensors. Unique microelectronics structures for medical sensors and circuits for their use. 9 Safety and reliability. Standards for medical applications and reliability issues for VLSI components.
This volume provides good specific references for a reader interested in a specific topic, and is an excellent introduction to the wide use of VLSI electronics in medical applications. With the fairly recent technological advances in material science, various polymers are now readily available for implantation. As this technology continues to advance, we will need to further understand the effects of different materials on the body and the effect of the body on these materials. In order to understand these phenomena, we must have a systematic way of investigating material properties and biological responses. It is also imperative that we look at the basic chemical reactions occurring between the material and the body.

Department of Electrical Engineering Texas A &M University
This text starts with these assumptions, and, after a short introductory chapter, provides a basic discussion on physiology and cellular biology. In this chapter, the authors review the makeup of different structures of the body, dedicating considerable space to several tissues and organs, including connective tissue, nerves, muscles, and teeth. On the other hand, they provide just a paragraph on the auditory system and never even mention the liver. On the surface, the selection of tissues and organs reviewed in detail seems to be random. However, a plausible reason for the selection may be that the areas discussed are the "hottest" topics at this time. In addition, almost any implant will come in contact with connective tissue, nerves, and muscle. This chapter ends with a summary of the type of biomaterials needed for different injuries and illnesses.
The next chapter starts with a review of basic cellular biology. The authors then discuss the physical, chemical, and physiological cellular responses to injury and trauma with a focus on the reactions that occur when a cell contacts a biomaterial.
The next chapter logically progresses to the response of the body to injuries and wounds. This chapter moves from a cellular response to a structural one. A large amount of space is dedicated to the response of blood-the different pathways that lead to coagulation and the factors that can trigger or inhibit these pathways. The effects and phases of inflammation are also discussed. The chapter concludes with the healing and repair processes of selected tissues and organs. Following this basic physiological review, the next two chapters move to the chemistry and physics of polymers.
The first of these chapters is a combination of organic chemistry and material science. It begins with the chemical composition of a selected group of polymers and some of their medical applications. It then moves to material science, reviewing basic topics such as the stress-strain curve, glassy transition temperature, charpy impact test, and the fatigue-failure curve. The importance and significance of these tests is mentioned throughout the chapter. The second of these chapters addresses the chemical characterization of different polymers. The focus here is on determining the quality of the polymer being used, with emphasis on the repeating polymeric unit and the level of impurities in the sample. The different chemical and mechanical tests for determining these values are discussed.
The third section of the book begins by presenting the methods available for evaluating biocompatibility. Toxicity and thrombosis testing are discussed and the importance of these tests is stressed. This is followed by a review of inflammation and infection testing, again showing the processes involved in their execution.
The next four chapters are dedicated to specific applications of polymers. The first covers wound dressings and artificial skin. It discusses the properties of an ideal wound dressing and various types of skin grafts where artificial membranes might be used. The second chapter in this group is dedicated to the replacement of skeletal soft tissue. The anatomy of several different joints and specific facial features is presented. The authors then explore the design of artificial tendons, ligaments, and cartilage for specific use in the joints and face. The next chapter covers the history and present status of cardiovascular implants. This presentation includes successes and failures as well as the inherent problems in using artificial and natural materials for valve, cardiac, and vascular replacements. The final chapter of this group examines the different polymeric materials that have been used for drug delivery, including the effects of the drugs on the polymers in these systems.
The final chapter is dedicated to a brief overview of Vol. 2, which is dedicated to metals, ceramics, and composite materials. This chapter, which is only two pages long, gives the reader a brief taste of these materials and the role they play in medical devices and biocompatibility.
This book is an excellent primer for anyone interested in the basic principles behind biocompatibility. The authors do an excellent job of covering the basic ideas that are important, without going into too much detail. Although they do a good job discussing where we have been and where we are, they fail to mention in any detail the possibilities of where we might be going (or should be going) in this field. In spite of the fact that this volume focuses on polymers, many of the ideas and concepts presented can be applied to other materials. The text is printed in an easy to ready type and there are extensive figures. The forty-five dollar price is a worthwhile investment for anyone who would like to gain a basic understanding of biocompatibility. This book would make a good text for an introductory class on biocompatibility; although, both volumes would probably be required, thus doubling the cost.

TIMOTHY W. KING Bioengineering Program Texas A&M University College Station, Texas 77843
Oral Implantology and Biomaterials. Edited by Haruyuki Kawahara. Institute of Clinical Materials, Osaka, Japan. Elsevier Science Publishers, 1989. 310 pp. $147.25. This publication presents the proceedings of the 3rd International Congress of Implantology and Biomaterials in Stomatology held April 27-29, 1988, in Osaka, Japan. Restoration of a dysfunctional tooth structure, utilizing artificial materials, has become an important science within today's medical realm. Recent implant material and biomaterial developments for dentistry purposes have proven themselves substantially effective. Therefore, the objectives of the congress as well as the text were to present and particularize new techniques, applications, and procedures; evaluations and examinations; and developing problems and possible effects.
Fourteen Japanese, five Europeans, four Americans, two Canadians, an Australian, and a Finn made up a diverse editorial board and served as chairs for the congress. The contributors of the articles also represented an international perspective. Distributed under nine specific topics, the contents of the book range from the extremely technical (e.g., "Specificities of Dentoosseous Interface and Induction of the Mimic Structure") to the less complex ("Basic and Clinical Evaluation of Zarconia Ceramic Dental Implant Systems").
Only five of the 46 reports in the volume were submitted by a single author. Almost half contained five or more contributors, signifying the importance of group research in relation to an expanding scientific field. One of the most interesting features of the book involves the various methods utilized in test procedures. Depending on the characteristics of the experiment, both humans and animals served in clinical trials. Each article presents specific details and results of the tests, emphasizing significant reactions, observations, and comparisons. From the particulars emerges the importance of design and material in conjunction with the complex feedback system of the human body.
Established under specific guidelines, each article contains a simple structure, incorporating illustrations and adequate data so the contributor(s) may present their findings in a systematic fashion. While most of the reports cover the necessities, some are too narrow for general interest and others too detailed. This problem could only be avoided through a total recomposition into an integrated presentation. However, this would defeat the purpose of this work, which is a presentation of the proceedings, Due to the increasing clinical success rate of newly developed biomaterials and implant materials, this text provides an important overview of recent implant techniques. This work presents papers given at a 1987 ASTM symposium sponsored by ASTM Committee F-4 on Medical and Surgical Materials and Devices and the Committee on Biomaterial Engineering of the American Academy of Orthopedic Surgeons. The collection begins with the editors' proposition that performance standards need to be adopted for fixation devices for fractures and joint replacement implants to replace the long-used convention of design standards. The twenty papers about intramedullary rods in this book discuss the mechanical properties of various nails, the effect of design on performance, the application of various rods in dissimilar bones and fractures, different methods for testing rods, and the results of clinical trials. Also included in the text is an author index and a relatively limited subject index.
Most of the papers are well documented with photographs, illustrations, and tables, where appropriate. However, only two papers contain generous use of references. Six papers analyze the mechanical properties of various intramedullary rods such as Kuntscher nails, 55O7o nickel and 45O7o titanium rods, Schneider nails, Hansen-Street nails, and Brooker-Wills femoral nails. Every paper contains a very detailed description of test methods and the results. However, due to different methods of testing, it remains difficult to compare one type of rod to another. In addition, the same method of testing was performed on Kuntscher nails in three different papers with the same conclusion. While useful as confirmation, the repeated details are not optimum in book form.
One of the more interesting papers is about testing methods. Until recently, most testing has addressed bending strength, bending rigidity, and torsional strength as separate properties. In actuality, bending and torsion are applied simultaneously to an implanted intramedullary nail. This paper presents a technique for mimicking physiological loading incurred by an intramedullary nail during walking and the results of tests performed using this method.
Eight papers discuss the application of various nails on bones of dissimilar quality and on different types of fractures and locations. These papers can be of very high value to orthopedic surgeons. By examining and comparing the results, the surgeon can, in principle, select the more appropriate intramedullary rod for the patient's specific needs. In addition, three papers presented at the end of the text are clinical trial results of various rods. Although the researchers present some conclusions, one must examine these results with skepticism since the circumstances in which the rods were used were not identical.
This book is of clear value to anyone active in the field of orthopedic prostheses or, more generally, in the area of biomaterials and implantable medical devices. In addition to being an interesting collection of mostly high-quality papers, it could be used by orthopedic surgeons as a guide when choosing intramedullary rods for specific patients or for specific fractures. Although clearly not a textbook or a general reference, this work has significant potential as supplemental material in courses on biomechanics and/or biomaterials. Even though this book is probably more informative for engineers than for clinicians, it is suitable for both groups. This book contains papers presented at a symposium of the same title held in New .Orleans in 1987. The 23 chapters included are largely concerned with biomedical or agricultural considerations and consist primarily of recent research results and applications. Only a few reviews are provided, and with the papers not divided into sections, orientation to the collection is difficult for the reader. The length of the original research articles varies from 5 to 20 pages with 8 to 53 citations. Both of the most extensively referenced articles provide new data on the incorporation or attachment of various antibiotics onto or into polymers. Included are effects on bacterial adhesion and of tetramisole and its platinum polyamine on the diabetogenesis of the diabetogenic D variant of encephalomyocarditis virus (EMC-D) in mice.

YUN S. CHOI
Unfortunately, these papers along with some other closely related material of pharmacological content are scattered among the various other contributions. These include the use of chitin and its derivatives as a plant growth activator, controlled release systems from biodegradable polymers, and metal-mediated controlled release of chelating agents or various types of grafted polymers with varied potential medical application. The last topic is introduced by an interesting summarizing paper by Daly and Lee entitled "Graft Copolymers of Amino Acids onto Natural and Synthetic Polymers." This paper is 24 pages long and has a very extensive list of citations. In the introductory section, the literature on grafting aminoacid N-carboxyanhydrides (NCAs) to proteins, natural polymers, and vinyl polymers is reviewed. In the experimental part, it is shown that poly(aminomethylarylene ether sulfone) as a soluble macroinitiator is effective in initiating the polymerization of the NCA of gama-benzyl-L-glutamate to produce soluble graft copolymers.
The last paper of original research in the book, by Yannas et al., updates important research on burn wound treatment with the use of collagen modifications interacting with the natural body tissues. Although only 5 pages long with 26 citations, this paper was given the Doolittle Award by the Division of Polymeric Materials as the best paper presented in the Division at the American Chemical Society National Meeting, New York, August 1987.
Two summary articles are included as Chapters 1 and 2 (17 and 28 pages, 129 and 99 citations, respectively). Chapter 1 (by the editors of the book and authors of the Preface) is a highly concise but extensive overview of biologically active synthetic and modified natural macromolecules with an emphasis on applications not otherwise covered in the book. It provides the bioactivity definition and a detailed classification of bioactive polymeric systems into the following three main classes: 1. controlled release systems (e.g., microcapsules, erodible and diffusion controlled systems), 2. biologically active polymers (natural and synthetic polymers), 3. immobilized or encapsulated bioactive materials (e.g., living cells, antigens, antibodies, etc.).
A summary of the medical, agrichemical, veterinarian, wood preservation, food processing and home use applications of biologically active polymers is given concisely in a table.
Chapter 2 considers in great detail the usefulness and effectiveness of polymers in pesticide applications over the period from 1976-1987. This is relevant to the recent general discussion about the pros and cons of agricultural applications of bioactive polymers. An overview of applications (flocculation control, spray drift control, devices using bioactive pesticide polymers, military wraps, plastic mulch and others) is given in a separate section of this chapter.
A short preface (two pages) by the editors provides the reader with a general idea about the book, characterizing each chapter with one or two sentences. A brief subject index of a sufficient extent is provided at the end of the book as well as a list of addresses of contributors.
As noted in the preface, the book was word-processed by CG ENTREPRISES, probably in an effort by the organizers and publisher to issue the volume as quickly as possible. One of the great merits of the book is that it appeared in 1988 as a collection of papers from the original symposium, which was held in autumn 1987. From this point of view, some formal imperfections are not of primary importance. The citations in both original research articles and reviews are not overwhelming but very instructive so that the reader may find a respective chapter of value for further inquiry into a particular subject area. The style of the individual chapters is unified so that the text is easily readable.
The book represents, without a doubt, a valuable source of information for everyone active in or wishing to enter the extensive area of bioactive polymeric materials research. As the fourth in the series of books by the same editors, this volume details some of the very recent developments of biological and biomedical applications of polymeric materials. This is the great merit of the book.