Engineer a disciplinary mix

Introduction to Bioengineering covers many bioengineering topics, although not nearly all of them. Commenting on the generality of engineering fields, Edwin Lewis, who contributes a chapter titled “Network theory” , says: “Bioengineering is the most general of all; none of the physical realms of engineering is excluded from the bioengineer’s repertoire.” One is reminded of G.G. Simpson’s remark that biology is the field where all the sciences are embedded. Because all of engineering is probably embedded there, too, it is not surprising that an introductory book on bioengineering should be broad in scope.

The book developed out of a “team-taught” introductory bioengineering course at the University of California at Berkeley, where the authors are primarily located. Werner Goldsmith and Stanley A. Berger, of the department of mechanical engineering, and Edwin R. Lewis, of the department of electrical engineering and computer sciences, are the editors. It may be worth noting that bioengineering is the newest department - established in 1998 - on the university’s campus and that Thomas Budinger, one of the book’ s contributors, is now professor and c hair of this department, of which Berger is also a member. It is surprising that departmental status for bioengineering arrived so late at Berkeley because an engineering group (professors Howard Eberhart and Charles Radcliffe, among others), along with orthopaedic surgeon Verne Inman and associates from the University of California , San Francisco, conducted seminal bioengineering studies there on human movement and limb prosthetics more than 50 years ago. This was probably the first bioengineering research in the United States to receive support from US government agencies.

Team teaching of an introductory topic such as bioengineering has many advantages for students because they are exposed to a variety of viewpoints by a number of lecturers. A course taught by the likes of Harry Skinner, Steven Lehman, Rodger Kram, Claire Farley or Thomas Budinger - to name only those authors the reviewer has personally heard - would be highly stimulating to young students. However, the collection of their writings, without their live personalities, appears to be something less. Instead, this edited book of 14 chapters, about 500 pages, encompassing almost 20 authors, presents an eclectic collection of articles , likely to be of greatest value as a reference book.

Besides being a useful reference, a strength of the book is its problem sets and examples. Goldsmith’s worked examples are appealing because they potentially allow a student to observe how a prominent biomechanician thinks and goes about the process of problem - solving. Not all the chapters have problem sets, but the sets available are potentially valuable to educators in bioengineering because good problems that are relevant and solvable are difficult and time-consuming to develop.
However, while solvable problems for student instruction are desirable , they also pose a problem because they may give students new to the field the idea that biological problems are regularly solvable by engineering methods. Engineering hubris that over - exaggerates what engineering can contribute to biological problems needs to be avoided. Perhaps a failing of Introduction to Bioengineering is that the reader could easily believe that biological problems readily yield to the mathematical concepts presented in chapter one , “Biomechanics of solids ”, by Goldsmith; chapter two , “Fluid mechanics ”, by Lawrence Talbot; chapter six,“ Modelling of physiological systems ”, by E.L. Keller; and chapter seven , “ Network theory”, by Lewis. These four chapters constitute almost half the book and are highly formalised.

It would have been advantageous if some of the early chapters (one to seven), which are concerned with basic engineering principles and engineering analysis techniques, had pointed out some of the pitfalls of applying traditional engineering methods directly to biology. Engineers can learn basic engineering principles and methods through the many engineering texts and courses available to them, but they need to be aware of the limitations and hazards of applying these approaches to biological problems. The formalism of these chapters is well presented, and is eminently successful in idealised engineering applications, but it may place too much emphasis on engineering analysis for an introductory text on bioengineering. This is especially the case if one feels that traditional engineering approaches must be considered carefully when transferred to biological problems that are frequently non-linear and non-stationary and where cause and effect are often not obvious.

Chapter seven, with its philosophical insights and elementary transducer theory, is challenging and could potentially form the foundation for an interesting monograph on transducers and instrumentation in bioengineering. In fact, several of the chapters could provide strong foundations for monographs.

Lehman, Kram and Farley state that the primary goal of their chapter , “Locomotion and muscle mechanics”, is to show how physics and anatomy can elucidate physiology (ie function). Bioengineering, it seems to this reviewer, can often elucidate function, organise thinking and sometimes solve biological problems with existing engineering methods. Ultimately, bioengineering may need to develop its own formalism.

The authors of chapter ten present sections called “Open issues” , which are concerned with poorly understood aspects of their field (locomotion, musculoskeletal biomechanics and muscle mechanics). It would have been beneficial to readers if “Open issues ” had been presented for most of the bioengineering fields covered in this book. But the way musculoskeletal systems are viewed in chapter ten is somewhat different from the viewpoint in chapter six. A model shown in chapter six presents the spinal cord reflex as a kind of position servomechanism to maintain steady posture, which is a concept no longer supported by the literature. Differences in viewpoint are common in science and engineering and are not adverse for students to read about , but this difference is fundamental. There may not have been as much communication as desirable between the lecturers / authors, which is a common occurrence in team teaching and in books that contain the contributions of several authors.

Chapter three, “ Physiological fluid mechanics” by Berger; chapter four , “Mass transfer” , by Michael C. Williams ; and chapter five , “Bioheat transfer” , by Takeshi K. Eto and Boris Rubinsky are fundamental in approach but are somewhat more based on biology and real physiological processes than on the, more or less, straight engineering analyses exemplified by the other opening chapters. This approach links theory and practice effectively.

R. B. Martin’s “Biomaterials” (chapter eight) and Harry B. Skinner’s material on “The interaction of biomaterials and biomechanics” (chapter nine) are appropriately introduced with engineering analysis applied to a number of practical applications, particularly those related to the bioengineering and surgical successes associated with the field of orthopaedic implants. Skinner, an engineer as well as an orthopaedic surgeon, is representative of the many bioengineers today with interdisciplinary educations.

Chapter 11, “Principles of electrophoretic separations” by Paul D. Grossman and David S. Soane, is the book’s nod toward the burgeoning fields of molecular biology and biotechnology. Chapters 12 t o 14 deal with areas that are often referred to as medical physics. Thomas F. Budinger’s article, “Medical imaging” (chapter 12), is particularly readable for the neophyte bioengineer. “Biological application of ionising radiation” by Selig N. Kaplan and Howard Maccabee (chapter 13) and “Bioeffects of nonionizing electromagnetic fields” by Charles Süsskind (chapter 14) are germane to imaging and to hazards of modern technology. But chapter 14, which is quite brief, was probably written before questions about the possible radiation hazards of cellular telephones became a topic of public concern.

Dudley Childress is professor of biomedical engineering, Northwestern University, Chicago, United States.