bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atomic Force Microscopy
Authors: Myhra Sverre 
Published: April 2006

Abstract
Atomic force microscopy, AFM, has emerged as the most widely used member of a group of related techniques known as scanning probe microscopy, SPM. The physical principle of the technique consists of a surface being probed by a sharp tip, in a manner where the strength of interaction between surface and tip is sensed by a lever transducer. In the context of biomedical engineering AFM has the particular merit of being able to image and manipulate bio‐systems with molecular spatial resolution and at strengths of interactions down to the low‐pN range. The versatility and richness of AFM analysis arise from the range of operational modes. Those include contact, lateral force and intermitting contact imaging modes, where the contrast arises, respectively, from topography, lateral chemical differentiation, and mapping of variations in mechanical stiffness. In the force‐sensing/imposing modes the probe‐to‐surface interaction is monitored as a function of distance and can provide insight into molecular binding and recognition, bio‐molecular folding, intra‐cellular structure and dynamics. The AFM system also constitutes a platform for exploration of novel bio‐sensor concepts.
Biochemical Pathways Research
Authors: Sherley James L. 
Published: April 2006

Abstract
All life on the planet is based on a set of basic biochemical reactions that provide energy transformation, biosynthesis, metabolism, and catabolism in cells. A unique feature of biochemistry is that chemical reactions are catalyzed by enzymes, which are chemistry‐specific in their action. Conceptually, enzymes and the biomolecules on which they act are arranged in pathways of sequential biochemical reactions. Biochemical pathway research has been a major force in the development of the principles of biomedicine and has greatly impacted medical knowledge and practice. In recent years, engineering disciplines like biomedical engineering have set their sights on elucidation and manipulation of cells as a strategy to making advances in biomedical research and medicine. However, in large part, these early efforts have been divorced of longstanding knowledge and scientific principles that are the fruits of biochemical pathway research. Improved progress in cell and tissue engineering in the future will require recognition that the failure to incorporate biochemical pathway concepts and knowledge in biomedical engineering pursuits is a severely limiting oversight. Such a paradigmatic shift in intellectual framework and approach will not be without significant challenges, but the certain gains in biological knowledge and effective medical applications more than outweigh such reservations.
Biocompatibility of Engineering Materials
Authors: Baier Robert 
Published: April 2006

AbstractAfter 30 years of human implantation of various commodity materials, backed up byin vitroand animal studies along the way, a secure knowledge base now exists regarding the critical bioadhesive phenomena encountered by biomedical devices that must resist or develop secure biological attachments. Well‐healed “osseointegrated” implants in human jaws signaled the significant—and, in many ways, surprising—advances that attention to surface properties and, especially, to surface cleanliness and surface energy of biomedical materials could foster for related systems.Two of the many active, successful areas of current patient benefits from biocompatible engineering materials are dental restoratives and prosthetic implants. Others include the continuing development of surgical adhesives, extracorporeal circuits, cardiovascular devices, fixed‐film processors, bioreactors, and even improved coatings for the prevention of marine fouling on commercial ships. A short review of the fundamental issues in some of these areas follows to illustrate the branches of medicine that are being addressed and how the technology of biocompatibility control assists in each of them.It is emphasized that principles of adhesion science and technology, respected at the earliest stages of these efforts, were and remain the key principles allowing safe and effective interfacing of engineering materials with biological systems.One major difficulty that had to be overcome in many early studies of biomedical implants for any use, be it in the dental, orthopedic, or cardiovascular environment, had been the tendency of the investigators to focus mainly on either the mid‐term (hours to days) and the longer term behavior of the materials—from weeks to months to years post‐implantation. There are numerous active research programs to provide proper characterization and detailed knowledge of the original surface states of these implants at their time of placement and of the early bioadhesive sequela (over minutes, hours, and days) converting the initial surface properties to others that promote or inhibit adhesion of formed biological elements (such as tissue cells or bacteria).
Resorbable Materials in Orthopedic Surgery
Authors: Borden Mark 
Published: April 2006

Abstract
Current techniques in orthopedic surgery use of a variety of implants that are specifically designed to aid in the healing of bones, ligaments, and tendons throughout the skeleton. These implants are commonly used to provide temporary mechanical support and stabilization to the site of the injury while the tissue heals. However, once their function is complete, the implants remain and can be a source of long‐term complications. Resorbable implants, on the other hand, are a unique class of devices that have the ability to breakdown into harmless byproducts that are absorbed by the body. Composed of polymers, ceramics, or composites, these versatile materials have different mechanisms of resorption, degradation profiles, and mechanical properties. As a result, they have been used in a variety of clinical applications including fracture repair, sports medicine, and bone grafting. This chapter discusses the requirements and function of resorbable orthopedic devices and reviews the properties and healing behavior of common resorbable materials.
Bioimpedance
Authors: Grimnes Sverre , Martinsen Ørjan G. 
Published: April 2006

AbstractBioimpedance describes the passive electrical properties of biological materials and serves as an indirect transducing mechanism for physiological events, often in cases where no specific transducer for that event exists.The studied biomaterial may be living tissue, dead tissue, or organic material. Tissue is composed of cells with poorly conducting, thin‐cell membranes; therefore, tissue has capacitive properties: the higher the frequency, the lower the impedance. Tissue is also anisotropic. Impedance spectroscopy, hence, gives important information about tissue and membrane structures, as well as intra‐ and extracellular liquid distributions.The three most common electrode systems are described. Typical results obtained with three‐ and four‐electrode systems are shown, and dispersion is explained. The effect of electrode polarization is demonstrated.The importance of system geometry, sensitivity, and reciprocity is explained. How bioimpedance can be used for volume measurements (plethysmography) is described. The sensitivity field of an electrode system is defined and explained and examples are provided.Bioimpedance electrical models are based on tissue showing relaxation, but not resonance, phenomena. The choice between an impedance or admittance model is underlined. The Constant Phase Element (CPE) and the Cole models are critically described, and a new general model is introduced.Some electrode design concepts are treated. Lock‐in amplifiers are the preferred instrumentation for bioimpedance measurements, together with advanced software for data analysis. The electrical safety aspects are treated.Selected applications and future trends are described. Bibliography and sources for reference data are given.
Biomedical Transducers
Authors: Togawa Tatsuo 
Published: April 2006

Abstract
A transducer is a device that converts a measured object quantity into an electrical signal. Biomedical transducers are transducers with specific uses in biomedical applications, such as physiological measurement and patient monitoring, and in health care. The object quantities in biomedical measurements are physical and chemical quantities that reflect the physiological functions in a living body. Although some quantities, such as blood composition, can be determined from a sample extracted from the body, real‐time and continuous measurements can be achieved if a transducer is attached to the body, and use of a transducer attached to the body is essential when continuous monitoring of an object quantity is required.
Blood Flow Measurement
Authors: Masood Sharmeen , Yang Guang-Zhong 
Published: April 2006

Abstract

The measurement of blood flow is important to the understanding and management of cardiovascular disease. The development of new imaging methods has allowed detailed quantification of
in vivo
blood flow that has traditionally been difficult. Both invasive and noninvasive methods have been used to measure blood flow, and this chapter outlines the main techniques of blood flow measurement for cardiovascular research and practical clinical applications. A brief history and the basic principles of each of the methods are presented along with their relative merits and potential pitfalls. Recent development of noninvasive imaging techniques has allowed detailed depiction and quantification of
in vivo
flow patterns, the main focus of this chapter is therefore directed towards Doppler ultrasound and cardiovascular magnetic resonance (CMR). The future trend of combining different imaging modalities for investigating the relationships between morphological structure and the hemodynamic properties of flow is also outlined.
Bulk Modulus
Authors: Aritan Serdar 
Published: April 2006

Abstract
Understanding and characterizing the mechanical response of soft biological tissues is a fundamental problem in biomechanics. Adequate models are needed to allow the study of both normal tissue function and the effects of disease and injury on these tissues.
The mechanical behavior of biological materials is determined by their structure. The factors which control mechanical response include the gross (bulk) and microscopic tissue morphology, the chemical composition of the tissue, fluid flow in the tissue, directionality of tissue fibre structures, and the interfaces between various structures.
Computer Aided Design
Authors: Knopf George K. , Johnson James A. 
Published: April 2006

AbstractComputer‐aided design (CAD) plays a key role in a variety of medical applications including prosthesis design, surgical implant design, blood flow analysis, preoperative planning for surgical operations, and computer‐assisted surgery. CAD tools and technology developed for mechanical design have been successfully applied to geometric modeling, visualizing, animating, and analyzing the natural functional behavior of anatomical structures including human skeletal and vascular systems. These shape modeling and visualization tools provide a significant amount of design information concerning object shape, dimensional parameters, component materials, material flow, and interference checking. New developments in virtual reality (VR) and rapid prototyping (RP) technologies have also enabled biomedical engineers to create detailed three‐dimensional (3‐D) models of anatomical structures directly from the CAD database. The immersive VR environments provide designers, physicians, and surgeons with the ability to interactively manipulate the geometric CAD models with 3‐D displays and haptic devices. In contrast, the fabricated RP prototypes give surgeons a realistic hard copy of complex structures before a medical implant is inserted or a surgical procedure is performed. The shift from the purely graphical interpretation of complex geometric models displayed on a computer monitor to an interactive visual‐tactile representation of the anatomical structure has the ability to deliver a new level of spatial understanding to designers and medical personnel.
Cancer
Authors: Yang Jia-Lin , Yu Yan 
Published: April 2006

AbstractCancer is a group of lethal diseases caused by uncontrolled growth and spread of abnormal cells. The cause is often not clear, which makes early diagnosis and effective treatment very difficult. Advances in biomedical engineering have allowed for the development of novel diagnostic and therapeutic methods via different approaches ranging from engineered biomolecules to cells to tissues that have improved cancer research and treatment dramatically. This chapter introduces some applications of biomedical engineering in cancer diagnosis and treatment.
Cell Adhesion Molecules – Conversational Signalers
Authors: Douglas Mike R. , Buckley Christopher D. 
Published: April 2006

AbstractCellular actions and fates—gene expression, differentiation, proliferation, apoptosis, and migration—are modulated by a sequence of signals that include the multiple adhesive contacts found between cells and their extracellular environment. A family of cell surface proteins, termed cell adhesion molecules, are important in mediating interactions. These proteins are segregated into distinct families with a wide range of physical properties. Some members exhibit strong binding properties, important for the maintenance of tissue integrity, whereas other members form weaker, more dynamic binding interactions, which are important during cellular migration processes. Research has demonstrated that these proteins are extremely versatile biological players, not only providing a form of cellular glue but also providing a means for coordinating a wide range of intracellular signaling events (including receptor tyrosine kinases and phosphatases), which have important functional consequences for processes as diverse as gene expression, cellular differentiation, migration, proliferation, and apoptosis. This review will briefly highlight the physical and biochemical properties that categorize cell surface molecules as adhesion molecules and demonstrate how these proteins form important modulators of cellular conversation by acting as assembly points for cytosolic adaptor proteins. The examples in this review are restricted to the signaling events coordinated by the integrin, immunoglobulin superfamily (Ig) cell adhesion molecules, cadherin/catenin families, and the selectins. These families exhibit a broad spectrum of biophysical and biochemical characteristics and yet all clearly demonstrate common dynamic interactions, forming multiprotein complexes linked to intracellular proteins and resultant signaling events.
Chaos
Authors: Cohen Maurice E. 
Published: April 2006

AbstractThe theory of chaos was developed approximately 30 years ago and initially applied in meteorology. Chaotic systems are characterized by nonlinear representations whose long‐term behavior is sensitive to initial conditions. Although the results may appear random, the systems are in fact deterministic and repeatable if all conditions remain the same. Chaos theory has been applied to the analysis of biomedical time series, especially in electrocardiogram analysis for examination of cardiac disorders. Chaotic analysis is based on the use of one or more measures of chaos that include both graphical and numerical representations. Most chaotic models are discrete in nature.Examination of continuous models shows that some chaotic behavior is from the discrete representation, and the methods derived from continuous modeling can be used in both chaotic and nonchaotic situations. Chaos, nonlinear dynamics, and complex systems have become linked and have expanded into new areas of application in biomedicine, including examination of interactions of multiple components from the cellular to the body system level.
Clinical Trials
Authors: Bartoo Grace T. 
Published: April 2006

Abstract
Human subject studies or clinical trials of a medical device are often required before a new device can be sold in the marketplace. The goal of a human subject study is to show safety and efficacy of a new device. However, the history of using human subjects in experiments has had a checkered past, resulting in a mass of governmental regulation aimed at ensuring reasonable subject safety while enforcing reliable scientific method. This article offers a brief overview of the structure, relevant regulations, and major steps that make up a clinical trial. It defines the roles of the various participants and emphasizes the responsibilities required of the sponsor and the clinical investigator. A brief overview of relevant regulations, standards, and guidance documents is given, with specific links to useful websites. In addition, the different regulatory requirements of significant versus nonsignificant risk devices are discussed. Finally, a synopsis of the preparation, execution, and analysis and reporting of clinical studies is given. Human clinical trials are complex, but when methodical efforts are made to follow and comply with regulatory and scientific requirements, reliable data can be generated while treating human subjects in an ethical and safety‐conscious manner.
Closed‐Loop System Identification
Authors: Baselli Giuseppe , Bolzern Paolo 
Published: April 2006

AbstractSystem identification concerns modeling of system dynamics through the choice of suitable mathematical laws and the estimate of their parameters from experimental data. General issues of open‐loop identification and input/output prediction error methods are briefly recalled in order to introduce the problems of closed‐loop identification. The main approaches to closed‐loop identification of feedback control systems are mentioned: direct, indirect, and joint process. Hypotheses required for each approach are stressed and asymptotic results concerning estimate consistency, accuracy, and bias in the frequency domain are provided. Major classes of biomedical application problems are introduced: modeling of physiological control systems, artificial control of physiological variables, and human/machine interaction.
Cochlear Implants
Authors: McDermott Hugh J. 
Published: April 2006

AbstractCochlear implants (CIs) are electronic systems that provide a partial replacement of the sense of hearing to people who have hearing impairment that cannot be alleviated adequately by means of conventional acoustic aids. In most cases of hearing loss, conventional aids that function principally as sound amplifiers are satisfactory. However, if the loss of hearing sensitivity in both ears is severe or profound, particularly across a wide range of frequencies, then amplification with conventional hearing aids may be inadequate. CIs have been developed to bypass the dysfunctional parts of the auditory system. They create hearing sensations by delivering electric stimuli directly to the auditory nerve via one or more electrodes located inside the cochlea (or inner ear). Recipients of CIs wear a device similar in appearance to an acoustic hearing aid on the external ear. This device contains a microphone, a signal processor, and a battery. In most existing CI systems, the external device transmits digitally encoded signals to an implanted receiver‐stimulator via a pair of inductively coupled coils. The implanted device decodes these signals and generates precisely controlled pulses of current that are delivered to the electrodes to stimulate the auditory neurons. The patterns of current pulses are designed to represent selected components of the sound signal received by the microphone. Over the past 30 years, a considerable research effort has led to the development of various algorithms that convert sound signals into electric stimuli for CIs. The most successful of these schemes enable numerous CI users to understand speech and recognize many other types of sound by hearing alone, at least in favorable listening conditions. By the end of 2005, over 70,000 adults and children around the world were recipients of CI systems.
Coherence
Authors: Ropella Kristina M. , Imas Olga A. 
Published: April 2006

AbstractCoherence is a frequency‐domain measure of the linear correlation between two time series that has been used extensively in biomedical signal processing applications. A number of numerical methods exist for estimating coherence from two or more time series, including time‐frequency implementations for nonstationary processes. Coherence may also be used for system identification. Examples of coherence spectra applied to the description of cardiac arrhythmias, and electrical and hemodynamic brain activity are emphasized in this article.
Blood Flow Simulation, Patient‐Specificin‐vivo
Authors: Merrifield Robert , Long Quan , Xu Yun , Yang Guang-Zhong 
Published: April 2006

AbstractThe blood flow patternsin vivoare complex. They vary considerably from subject to subject and even more so in patients with cardiovascular diseases. Despite the importance of studying such flow patterns, the field is relatively immature primarily because of previous limitations in the methodologies involved in acquiring and calculating expected flow details. Althoughin vivoimaging provides a valuable investigative tool, the range of hemodynamic properties that can be measured is limited. Computational fluid dynamics (CFD), on the other hand, offers a complementary approach that permits the simulation of blood flow within patient specific cardiovascular models. It allows the calculation of high‐resolution flow fields and hemodynamic indices that cannot be measured using imaging alone. The parallel advancement of magnetic resonance imaging and CFD has now come to a stage that their combined application will allow for a more accurate and detailed measurement of complex flow patterns. This article introduces the main processes involved in flow simulation including imaging, segmentation, meshing, and numerical simulation. For each of these issues, the current approach and remaining challenges are discussed.
Computer Aided Surgery
Authors: Cleary Kevin , Buersmeyer Todd , Wood Bradford J. , Glossop Neil 
Published: April 2006

AbstractComputer‐aided surgery, in which computers are used to provide image guidance to physicians for invasive procedures, is still a relatively new field. Most developments have come over the last 10 years. Systems based on bony landmarks for applications such as the brain, spine, and ear, nose, and throat are now commercially available, and some institutions use them as the standard for care. However, systems for abdominal interventions and for other procedures with substantial organ motion and deformation have not yet been developed, and they constitute an area of current research.A typical computer‐aided surgery system has three major components: a control computer, a localizer for tracking instruments, and software for image processing and display. The localizer can be optical or electromagnetic; however, most commercial systems use optical localizers. Electromagnetic localizers show promise for future applications, including tracking of internal organs, but recent technological advances have only now rendered them serious contenders for this purpose.Computer‐aided surgery is an active area of research and emphasizes collaborations between biomedical engineers and clinical experts. Research areas include integration of real‐time modalities, such as ultrasound, to provide intraoperative updates; modeling of soft‐tissue deformation and respiratory motion; new registration and tracking techniques; multimodal image fusion; and improvement of visualization methods.