bluuebunny/crossref_metadata_2025 huggingface dataset:
Electroencephalography (EEG)
Authors: Blinowska Katarzyna , Durka Piotr
Published: April 2006

Electroencephalography is a domain concerning recording and interpretation of the electroencephalogram. Electroencephalogram (EEG) is a record of the electric signal generated by the cooperative action of brain cells, or more precisely, the time course of an extracellular field potentials generated by their synchronous action. Electroencephalogram derives from the Greek words enkephalo (brain) and graphein (to write). EEG can be measured by means of electrodes placed on the scalp or directly on the cortex. In the latter case, it is sometimes called electrocorticogram (ECoG). Electric fields measured intracortically were named Local Fields Potentials (LFP). EEG recorded in the absence of an external stimulus is called spontaneous EEG; EEG generated as a response to external or internal stimulus is called an event‐related potential (ERP. The amplitude of EEG of a normal subject in the awake state recorded with the scalp electrodes is 10–100 μV. In case of epilepsy, the EEG amplitudes may increase by almost an order of magnitude. In the cortex, amplitudes are in the range 500–1500 μV.
Electromagnetic Interference and Compatibility
Authors: Silva Ferran , Fernandez Mireya , Riu Pere J.
Published: April 2006

Electromagnetic compatibility (EMC) is defined as the ability of electronic equipment to work as intended in the presence of certain electromagnetic interferences. To achieve this goal in medical equipment, emissions and immunity must be addressed. Emissions from electronic equipment must be limited in order to not create an electromagnetic environment too harsh so that other equipment is unable to work. At the same time, equipment immunity must be achieved to avoid any critical malfunction when the equipment is working in a typical environment where a certain level of perturbation exists.
Extracellular Matrix
Authors: Melrose James , Whitelock John M.
Published: April 2006

The extracellular matrix (ECM) is a complex composite biomaterial with critical structural and functional roles to play in connective tissues. The cells embedded within the ECM provide the biosynthetic machinery for the synthesis and secretion of the complex array of interactive molecules that are required for its assembly. The major components of ECMs are glycoproteins, collagens, proteoglycans, and elastin. ECMs are heterogeneous both between connective tissues and within a single tissue type during development/maturation or with ECM remodeling events associated with pathologic processes. Some connective tissues are highly cellular and contain relatively little ECM (e.g., muscle, kidney, liver) whereas others contain an abundant ECM and relatively few cells (e.g., cartilage, tendon). Some tissues contain mineralized matrices (e.g., bone, dentine) whereas the ECM of others have gel‐like consistencies (e.g., vitreous humour, synovial fluid, Wharton's jelly), reflecting their relative contributions to weight bearing, internal organ cushioning, or lubrication of joint surfaces. For the purposes of this chapter, cartilage was selected as a representative tissue because of its relatively simple structure, containing ∼5% cells but approximately 90% ECM. The chondrocytes in hyaline cartilage, however, have well‐defined pericellular, territorial, and inter‐territorial matrices and characteristic cellular arrangements (chondrons) in the superficial, intermediate, and deep zones of this tissue. It is therefore possible to identify different functional compartments in the cartilage ECM and to categorize the proteins within them, which offers heuristic advantages.
Extracorporeal Membrane Oxygenation
Authors: Conrad Steven A. , Keith Scott L.
Published: April 2006

Extracorporeal membrane oxygenation (ECMO) is the provision of long‐term support for severe, potentially reversible cardiopulmonary failure through the use of extrathoracic cannulation and an extracorporeal circuit. The extracorporeal circuit is a modification of the heart‐lung machine used in cardiac bypass surgery and consists of a drainage reservoir, blood pump, artificial lung for oxygen and carbon dioxide exchange, a heat exchanger for maintenance of body temperature, cannulae for vascular access, and connecting tubing. ECMO is used in the management of severe, acute, potentially reversible cardiopulmonary failure in neonates, children, and adults. The modes of support include venoarterial (VA), venovenous (VV), arteriovenous (AV), and hybrid VA and VV (VVA). Venoarterial support bypasses the heart and lungs and provides cardiac and pulmonary support. Venovenous provides gas exchange in the central venous circulation, and it provides pulmonary support only. Arteriovenous is performed using an artificial lung without a pump, but provides carbon dioxide removal only. VVA mode combines partial cardiac support in addition to pulmonary support.

The performance of the ECMO circuit depends on several factors. Blood flow is dependent on geometry of the vascular cannulae, tubing, and artificial lung, and it includes laminar and turbulent flow. Pressure‐flow relationships for ECMO circuit components have been published. Gas exchange efficiency in venovenous ECMO is affected by recirculation. The determinants of artificial lung gas transfer are complex but based on principles of passive diffusion. Modern cross‐flow hollow fiber devices that have blood flow exterior to the fibers demonstrate the best blood flow and gas transfer performance.
Fatigue
Authors: Roca-Dorda Joaquin , Roca-González Joaquín , Martínez-Gonzalez Francisco , Guillamón-Frutos Antonio
Published: April 2006

The study of fatigue has increased by leaps and bounds; however, still no universal definition exists and fatigue remains a vague concept used as an umbrella term that comprises of physiological, emotional, and behavioral factors that can result in chronic physical or mental states affecting the cognitive, memory, motoric, and perceptive capacities. Biomedical engineering has faced fatigue evaluation from two different approaches: exercise‐induced fatigue (or metabolic fatigue) and central fatigue (related to the evolution of the subject condition caused by the execution of normal tasks). As metabolic fatigue is a complex mechanism usually discussed by exercise physiology, this work will center on central fatigue detection and evaluation, because of its importance within the field of human factors engineering in occupational health studies. Central fatigue has been referred to in various terms that are more or less mutually interchangeable in the research literature: loss of alertness or vigilance, fatigue, and drowsiness, although no significant difference exists among them.

Research has focused on the development of objective and reliable measurement techniques able to quantify the state of human deteriorated condition, although none of the proposed methods has been yet considered to be a gold standard. This work reviews several fatigue indicators that have been reported to reflect the different dimensions resulting from this state [heart‐related measures such as the heart rate (HR) and heart rate variability (HRV), muscles activity through electromyogram (EMG) and mechanomyogram (MMG), spectral analysis of the electroencephalograph (EEG) and event‐related potential (ERP), ocular metrics, speech parameters, etc].
Fiber Optic Sensors
Authors: Yin Stuart (Shizhuo) , Ruffin Paul
Published: April 2006

Fiber optic sensors have become indispensable tools for biomedical study because of their unique features such as (1) high sensitivity, (2) small footprint and endoscopic compatibility, (3) multiple agent distributive sensing capability, and (4) immunity from electromagnetic interference. In this chapter, we will provide a brief overview on the basic principle of fiber optic sensors, types of fiber optic sensors, and their applications to biomedical sensing. As a result of the page limitation, important work in this area may not be included in this chapter. Readers may find those contents in the listed reference material.
Force Measurement
Authors: Anderson I.A. , Lim K.
Published: April 2006

A variety of transduction technologies are available for the measurement of force. Some of the more common ones, including strain gauge and piezoelectric types, are described in this article. There are several important considerations when dealing with force measurement, which include measurement range, linearity, accuracy, sensitivity, frequency response, and aliasing. The accuracy of the force measurement can be limited by incorrect interpretation of the output from a transducer. Errors can occur due to poor sensitivity and nonlinear behavior. The measurement of dynamic force also requires consideration of the frequency response characteristics of a transducer. To avoid large errors, it is important to choose a force transducer with a natural frequency that is significantly greater than the maximum frequency of interest in the force measurement. Choice of transduction technology will deal with most of these issues to a greater or lesser degree. Examples of specific applications of force measurement in biomedical engineering will be presented in this article.
Forward Problem
Authors: de Munck J.C. , Heethaar R.M.
Published: April 2006

Forward problems show up when information is extracted from recorded data, which cannot be assessed directly. An example is the epi‐cardial potential distribution in a healthy volunteer. This article presents a short and qualitative overview of the forward problem, as it appears in biomedical engineering. The main focus is in electroencephalography (EEG) and impedance tomography (EIT). As in real applications the forward problem has to be solved for many combinations of parameters, computational speed is important. Also, the solution needs to be accurate, to avoid systematic errors.
Fuzzy Neural Networks
Authors: Melek William W. , Yeow John T.W.
Published: April 2006

This chapter provides a comprehensive review of fuzzy neural network models. Existing methods to combine fuzzy logic and neural networks are presented. Several classifications of fuzzy neural networks are provided. Those classifications are based on the type of application of the fuzzy neural network. Fuzzy neural network models with supervised learning features are also reviewed in detail. A review of various biomedical engineering applications that use fuzzy neural networks is also presented. Some future medical science applications of fuzzy neural networks are described. A complete bibliography is listed at the end of the chapter.
Haptic Devices and Interfaces
Authors: Repperger Daniel W. , Phillips Chandler A.
Published: April 2006

The sense of touch (somatic or haptic) involving force‐reflecting devices acting on, or in conjunction with, human movement, provides a powerful paradigm to assist individuals in shaping their biodynamic actions in specific tasks or scenarios. Haptics can behave as both a sensor (force display) or an actuator (controller) with much research accomplished in both areas. First a survey on current biomedical and rehabilitation applications is provided. A specific biomedical example is then presented that deals with modulating control motions made by physically challenged individuals that enabled more voluntary control. Finally, the future applicability of haptics or force reflecting technology is given.
Heart Rate Variability (HRV)
Authors: Akselrod Solange , Pinhas Itzik , Davrath Linda R. , Shinar Zvika , Toledo Eran
Published: April 2006

One of the important and challenging fields in cardiovascular research is the investigation of its control mechanisms, which regulate cardiovascular function in response to alterations in physiological, environmental, and emotional states. The main variables under control are heart rate (HR) and blood pressure (BP). Their role is to maintain homeostasis. Essential quantitative information about neural and humoral cardiovascular control can be noninvasively obtained by applying computerized, mathematical, and physical tools for the processing of basic signals, such as heart rate, blood pressure, blood flow, and other related physiological signals.

The measurement of the mean HR (or BP) is of utmost importance and is a first‐order indicator of the patient's well‐being. However, heart rate variability (HRV) completes the picture, expressing by its fluctuations the levels of autonomic neural input to the SA node. It is important to emphasize the noninvasiveness of this approach and its ability to extract valid continuous (beat‐to‐beat) information in the time domain, the frequency domain, and the time‐frequency domain.

Careful HRV analysis reveals noninvasive quantitative information of the parasympathetic, sympathetic (alpha and beta) activity and control (of the SA node), combined with all the active feedback mechanisms. Indirectly, it thus provides information on the BP control, mainly the direct vasomotor neural control as expressed by the reflex HR modulation. Respiration is a crucial contribution to HRV.

HRV provides insight into the autonomic nervous system and allows the computation of sensitive diagnostic parameters to be used for clinical applications.
Higher‐Order Spectral Analysis
Authors: Lipping Tarmo
Published: April 2006

The definitions of higher order moments, cumulants, and spectra are given. Direct and indirect methods of bispectrum estimation are described. The main properties of cumulants are presented together with the symmetry properties of the bispectrum. Finally, some application areas of higher order spectral analysis like removal of Gaussian noise, identification of non‐minimum phase systems, and detecting nonlinearities are discussed. The reader is referred to the literature containing thorough treatment of the subject.
Maximum Likelihood Estimation
Authors: Najarian Kayvan , Darvish Alireza
Published: April 2006

This article provides a brief survey of maximum likelihood estimation (MLE) and its applications in analysis of biomedical signals and images. The article also explains why MLE is a useful technique for both parameter estimation and pattern classification. Finally, some specific applications of MLE in biomedical engineering are briefly described.
Mechanical Testing
Authors: Gillies Ronald Mark
Published: April 2006

Mechanical testing is the investigation of the relationship between the structure and properties of a material. It is an avenue to evaluate the design of a structure‐property correlation, where the design must conform to an agreed standard. In biomedical engineering, these mechanical tests are usually the investigation of biocompatible devices and biological tissues. The mechanical tests or simulations may involve joint or organ kinematics and load deformation characteristics of soft tissues. The biomechanics involved in the motion of the joints are complex and require an ability to simulate the contraction and antagonistic relaxation of the involved muscle groups. The majority of mechanical testing specifications are normally defined by standards organizations or published guidelines.
Mechanomyography
Authors: Orizio Claudio , Gobbo Massimiliano
Published: April 2006

This chapter on surface mechanomyography (MMG) is aimed to provide basic information about a relatively new biological signal detectable at the muscle surface during contraction. The text will deal with the definition and terminology; the relationship between the activity of the single motor units and the signal generation process and, as a consequence, on the MMG reliability as a tool to reveal the motor units activation strategy, the relationship between MMG and muscle mechanics to disclose the possible use of this signal to get information about muscle contractile properties; and finally some examples of practical applications in physiological and clinical studies. The goal of this chapter is not to provide an extensive review on the MMG but only to underline some physiological and technical aspects that the spreading of its use may be based on.
Medical Device Acquisition
Authors: Silva Ricardo , Alkhateeb Abdalhameed , Gaumond Roger
Published: April 2006

A clinical institution is always in search of new technology and of new equipment. These purchases can wreck operating budgets if mishandled. The need for each purchase must be well understood, and the total costs, including all installation and operating costs, must be considered. A key element is the negotiation process between the hospital's acquisition committee and the vendor.
Medical Device Industry
Authors: Panescu Dorin
Published: April 2006

In its basic form, medical technology development has been reported since the early days of recorded history. However, most technologies and devices that markedly improved human health and increased life expectancy have been developed in the last half century. Although in the last two decades economic cycles and uncertainties have affected several industries, the medical device sector reaped the benefits of earlier investments and delivered unmatched improvements in life quality. The U.S. medical technology industry is the largest producer of medical devices and diagnostics, with production evaluated at $77 billion in 2002. Medical device firms invested about 11% of their revenues in research and development, more than any other industrial sector with the exception of pharmaceuticals manufacturers. As a result, between 1980 and 2000, the heart attack mortality decreased by about 40%, the stroke deaths declined by 37%, diabetes complications were 25% fewer, and breast cancer mortality was 20% lower. Americans now have a life expectancy at birth of 76.5 years. This article reviews the progress made in the medical device industry in the last 25 years.
Optical Microscopy
Authors: Diaspro Alberto , Usai Cesare
Published: April 2006

Microscopy studies the enlargement of the image of objects too small to be properly seen by the unaided eye. Microscopy accomplishes its task making use of the radiations emitted, absorbed, transmitted, or reflected by the specimen to be observed. The nature of the radiation specifies the type of microscopy: electron microscopy, x‐ray microscopy, acoustic microscopy, etc. The visible part of electromagnetic spectrum is the type of radiation used by optical microscopy.
Pattern Classification
Authors: Hudson Donna L.
Published: April 2006

The first computerized medical decision support systems were based on pattern classification techniques. Early applications were focused on the diagnosis of disease. The process involved determination of parameters that were potentially useful in classification of cases into two or more categories. The parameters, denoted features, were organized as vector components. Numerous learning algorithms were developed that were trained on available data both for supervised learning in which correct classification of cases was known and unsupervised learning in which the classification was unknown and occasionally even the number of classes was unknown. The models were very successful and multiplied rapidly. Applications of pattern recognition in decision making came to be known as pattern classification, whereas pattern recognition is more often associated with recognition of patterns in images. The basic techniques are the same, with the differences originating in the feature identification phase. Neural networks are special types of pattern classification algorithms that use architecture based on biological nervous systems.
Photodiodes
Authors: Gray Bonnie
Published: April 2006

A photodiode is a solid‐state sensor that responds to light by producing a measurable electronic current. Operating as a quantum threshold detector, a photodiode will only detect photons that exceed a certain energy level (the bandgap energy of the photodiode material) while not detecting photons below this level. This article covers the basics of pn‐junction, PIN, and avalanche photodiode operation, as well as the use of photodiodes in several example applications in biology and medicine. Photodiodes are attractive for biomedical applications because they are inexpensive compared with many other detection mechanisms, easy to use, small scale, readily available, and capable of operation in an array for parallel sensing. They are ideal for applications involving bed‐side monitoring such as pulse oximetry, rapid diagnosis including point‐of‐care instrumentation based on lab‐on‐a‐chip technology, and other instances where equipment benefits from greater miniaturization or portability. Semiconductor photodiodes are fabricated using similar methods used to produce transistors and integrated circuits and continue to evolve together with integrated circuits to be efficient and inexpensive photodetectors while maintaining their basic simplicity.
Plethysmography
Authors: Valentinuzzi Max , Belalcazar Andres
Published: April 2006

After introducing the concept of plethysmography, a basic elementary model is presented along with its mathematical description. The three sections that follow describe the main techniques traditionally used in this kind of measurement (i.e., mechanical plethysmography, photoplethysmography, and impedance plethysmography). The rest of the chapter deals with applications, first, as the so‐called body plethysmography for respiratory measurements, and second, as applied to specific body parts; these include the thorax, respiratory measurements, and the heart (for cardiac output). Finally, a brief reference is also made to limb's vascular assessment. A critical evaluation and discussion closes the chapter followed by a selected list of references.
Protein Structure, Folding, and Conformation
Authors: Najarian Kayvan , Ford Belma
Published: April 2006

The information needed to determine protein structure is contained in the amino acid sequence of the protein. The standard methods for determining protein structure, x‐ray crystallography and nuclear magnetic resonance (NMR), require a high‐quality crystal sample. Producing a quality sample is a time‐consuming and labor‐intensive process. This is the rate‐limiting step in structural proteomics. Researchers have turned to prediction methods to devise methods to predict a three‐dimensional protein structure. The most successful methods combine different techniques to address the challenge instead of relying only on sequence information. Some protein prediction method contains a model of the protein and the corresponding force field, a technique to scan the energy landscape, and techniques to analyze the prediction method. This article provides a brief survey of protein folding prediction methods.
Radiation Safety
Authors: Martin Colin J.
Published: April 2006

Radiation is used in a wide range of applications in hospitals and health care. It offers tremendous advantages in the ability to image, diagnose, and treat disease, but it can damage human health in various ways, the most important of which is increasing the risk of inducing cancer. This article discusses the risks from exposure to ionizing radiation, in both the short and the long term and considers the different routes through which staff and patients may be exposed to radiation in health care. The basic principles of radiation protection, detection of radiation, and management of radiation safety in a hospital environment are considered. The various types of risk from different applications are considered. For example, in radiology, the x‐rays are generated by equipment and present only an external hazard, whereas in nuclear medicine, radioactive materials are used that may be taken into the body and irradiate tissue from the inside. Finally, in radiotherapy, where radiation is used to kill cancer cells, the radiation levels are higher and greater precautions must be put in place to minimize the exposure of staff. Different ways in which radiation safety is achieved for the various applications are described. The article also considers the risks from nonionizing radiations in the form of optical radiations, i.e., lasers and ultraviolet that are hazardous to the eyes and skin, and electromagnetic fields, which heat tissue and may induce other effects.
Rehabilitation Engineering: An Overview
Authors: Cooper Rory A. , Ding Dan , Cooper Rosemarie , Wolf Erik , Algood David , Corfman Thomas , Rentschler Andrew J. , Boninger Michael L. , Chaves Eliana
Published: April 2006

Rehabilitation deals with correction or compensation for functional deficits not responsive to surgery or pharmacology. Rehabilitation engineering is the application of engineering science and technology to the medical rehabilitation of persons with disabilities. The scope of rehabilitation engineering extends from basic cellular and molecular engineering investigating potential therapies for people with disabilities to the other extreme, including direct clinical service delivery to persons with disabilities. The critical aspects of rehabilitation engineering education are that people are well grounded in engineering principles, scientific methods, clinical practices, advocacy and legislative issues, pathology, epidemiology, and disability.
Assistive Robotics
Authors: Hillman Michael R.
Published: April 2006

Robotic technology has great potential to benefit the lives of people with disabilities. Not only in the obvious role as a manipulator, whether mounted on a desk, wheelchair, mobile base, or body worn, but also as an aid to mobility, education, and communication. Assistive robotics is the bringing together of several technologies with the needs of people with various disabilities.
Spasticity and Upper Motor Neuron Dysfunction
Authors: Sherwood Arthur , McKay W. Barry
Published: April 2006

This chapter presents an overview of the set of symptoms generally classified as spasticity. Definitions of spasticity are reviewed, and this chapter suggests the use of a recently presented definition, “disordered sensori‐motor control, resulting from an upper motor neurone lesion, presenting as intermittent or sustained involuntary activation of muscles.” Following a brief discussion of mechanisms, assessment of spasticity is organized by consideration of the domains of the international classification of functioning, disability, and health (ICF) and clinical and laboratory scales reviewed.
Bioenergetics and Systemic Responses to Exercise
Authors: Verheyden Bart , Beckers Frank , Aubert André E.
Published: April 2006

Sport is the most popular form of culture in societies across the world. In the last 50 years, the multidisciplinary research area of exercise physiology has tremendously improved our knowledge about the systemic response and adaptations to exercise.

During exercise, the human metabolism gradually increases and is associated with a global increment in energy expenditure. Increased energy consumption is necessary to provide adenosine triphosphate (ATP) to the working musculature where it serves as the immediate source of energy. Muscle cells produce ATP by a single or a combination of three metabolic pathways depending on the type of exercise (intensity and duration). Generally, aerobic pathways provide a large amount of ATP low‐moderate intensities, whereas the anaerobic pathways provide a limited amount of ATP at near maximal to maximal intensities. A series of systemic structural and functional alterations enable an efficient energy delivery to the working musculature during exercise. Adaptations in the cardiovascular system enhance O2transport from the lungs to the target muscle. Increased pulmonary ventilation facilitates CO2removal and O2uptake in the lungs. The amount of O2that can be subtracted from the arterial capillaries in the working musculature can be improved by muscular adaptations to exercise. In fact, because exercise is a whole body commitment, acute alterations in a single exercise bout and adaptations to exercise will extend to all physiological systems of the body.

Although it is impossible to govern a detailed description of all the changes accompanying (repeated) physical exercise training, the first section of this chapter reviews some prior knowledge about the exercise metabolism and the most important systemic responses and adaptations to exercise. In the second section, an overview of the latest generation biomedical engineering contributions to the field of exercise physiology will be presented and some of the less known applications will be briefly described (e.g., pulse oximetry, magnetic resonance velocity mapping, and magnetic resonance spectroscopy).
Technology Assessment of Medical Devices
Authors: Cunningham David , King William , Henning Timothy
Published: April 2006

Technology assessment involves systematically gathering and weighing a wide variety of information in order to identify commercially viable opportunities. Small entrepreneurial companies and universities generate much of the new technology. A process often followed by large companies to find and evaluate new technologies is described with the aim of facilitating interactions between the holders of new technology and large companies. Technology assessment generally follows the steps of obtaining new leads, screening leads, evaluating preliminary technology, performing due diligence, and negotiating a deal. The importance of a clear business strategy and proper consideration of intellectual property are emphasized.
Telemedicine
Authors: Hung Kevin , Zhang Yuan-Ting
Published: April 2006

Telemedicine is the delivery of medical diagnosis, treatment, and patient care by means of telecommunication, information technologies, and electronic technologies with medical expertise. It helps to provide medical services to underserved areas and promotes medical resources sharing, cost reduction, and improvement in healthcare support for the current and foreseen aging population. Disciplines of telemedicine include teleanesthesia, telecardiology, teledermatology, teleconsultation, telemonitoring, home telecare, telepsychiatry, teleneurology, teleradiology, teleoncology, teleophthalmology, telepathology, and telesurgery. Various standards are used to ensure efficient communication between telemedicine systems and medical devices. A current trend is mobile telemedicine, which utilizes the emerging wireless communication and mobile computing platforms.
Ventilatory Pattern Variability in Mammals
Authors: Webber Charles L. , Zbilut Joseph P.
Published: April 2006

The mammalian ventilatory control system consists of coordinated actions of the central and peripheral nervous systems and muscles of breathing to effect dynamic expansions and contractions of the lungs. Mechanical and chemical feedbacks report on the status of the process in order to keep blood gas tensions of oxygen and carbon dioxide within homeostatic ranges. As a result of the nonlinear interactions of numerous variables, differential phasic delays between efferent and afferent signals, and the presence of noise and environmental perturbations, variables of breathing (tidal volume, cycle durations, etc.) normally exhibit fluctuations over many different time scales. Loss of dynamic flexibility because of central nervous system (CNS) damage or cardiovascular compromise can lead to abnormal and ominous breathing patterns incompatible with life. Mathematical models of ventilatory control instruct on how the breathing system is regulated in health and disease.
Virtual Instrumentation
Authors: Obrenović Željko , Starčević Dušan , Jovanov Emil
Published: April 2006

Virtual instrumentation merges sensing technologies with hardware and software technologies to create flexible and sophisticated instruments for various control and monitoring applications. Biomedical applications require sophisticated and flexible instrumentation, accomplished by using general‐purpose computing platforms with various application‐specific input/output devices. Virtual instrumentation brings many advantages over “conventional” instrumentation. Employing general‐purpose computing platforms significantly decreases the price of instruments. Standard system interfaces allow seamless integration of virtual instruments in a distributed system, whereas software reconfiguration facilitates flexibility and scalability. Most general virtual instrumentation concepts are directly applicable in biomedical applications; however, specific features of the biomedical instrumentation must be taken into account. In this article, we present a brief history and current state of virtual instrumentation for biomedical applications. We explain the general architecture of a virtual instrument, describe the most frequently used tools and platforms, and present typical examples of biomedical applications of virtual instrumentation.
Virtual Reality
Authors: Riva Giuseppe
Published: April 2006

The basis for the virtual reality (VR) idea is that a computer can synthesize a 3‐D graphical environment from numerical data. Using visual and auditory output devices, the human operator can experience the environment as if it was a part of the world. This computer‐generated world may be either a model of a real‐world object, such as a house, or an abstract world that does not exist in a real sense but is understood by humans, such as a chemical molecule or a representation of a set of data, or it might be in a completely imaginary science fiction world. Further, because input devices sense the operator's reactions and motions, the operator can modify the synthetic environment, creating the illusion of interacting with and thus being immersed within the environment.

These characteristics also allow a definition of VR in terms of human experience: a real or simulated environment in which a perceiver has the experience of presence in an environment by means of a communication medium. This definition clarifies the possible role of VR in medicine: a communication interface based on interactive 3‐D visualization, able to collect and integrate different inputs and datasets in a single real‐like experience.
Wheelchair Engineering
Authors: Cooper Rory , Ding Dan , Kwarciak Andrew M. , Cooper Rosemarie , Guo Songfeng , Spaeth Donald M. , Zipfel Emily , Kelleher Annmarie , Boninger Michael L.
Published: April 2006

The wheelchair is one of the most frequently used devices by people with disabilities. Wheelchairs provide mobility, seated support and access to the community. Designing, selecting, fitting and engineering wheelchairs is deceptively complex, and new technologies are adopting more and even leading areas such as robotics, and automotive engineering. There are a wide variety of wheelchairs needed to match the demands of users, and to accommodate the changing dynamics of disability. This chapter will describe various types of wheelchairs and their interfaces.
Wound Healing
Authors: Poole-Warren Laura A. , Ly Mai
Published: April 2006

Wound healing normally progresses via a cascade of events beginning with hemostatsis and migration of inflammatory cells, followed by angiogenesis, matrix deposition, epithelial regeneration (in cutaneous and other epithelialised tissues), and remodeling of the newly deposited tissue matrix. In nonhealing or chronic wounds, this process seems to be disrupted and often fails to produce the vascularized granulation tissue needed for tissue repair. Technological advances over the past two to three decades have provided many new approaches to wound therapy. These include novel biomaterials for wound dressings, engineered drugs and drug delivery systems, tissue‐engineered interactive wound coverings, hyperbaric oxygen therapy, nitric oxide releasing agents, and various physical therapies including devices for electrical stimulation and photostimulation. Many of these have reached clinical practice, and some have generated improvements in wound healing rates. Barriers to adoption of new technologies for wound healing include complex application methods, failure to demonstrate significant benefits in animal and clinical trials, and the vast differences between therapies required for different wound types at different stages. Consequently, this extremely crowded market offers a high degree of choice between the many therapies for which there is often insufficient evidence of efficacy. Although traditional therapies such as saline‐soaked gauze persist, the future offers hope in many forms, via better understanding of cell and molecular processes involved in wound healing and combined approaches to therapy.
Blood Oxygen Saturation Measurements
Authors: Teng Xiao-Fei , Zhang Yuan-Ting
Published: April 2006

Blood oxygen saturation indicates the percentage of hemoglobin molecules saturated with oxygen. It is a vital sign of a patient's health, considering that without a constant oxygen supply, a human being cannot survive for a prolonged time. Blood oxygen saturation measurements can be categorized into chemical methods and optical methods. Chemical methods need a blood sample forin vitroanalysis, whereas optical methods measure blood oxygen saturation by passing specific wavelengths of light through the blood. As optical methods can achieve measurements noninvasively, they have been widely used in clinical applications. Among the optical methods, pulse oximetry, which can measure blood oxygen saturation with comparable accuracy, is the one that has been widely used in clinical environments. Beyond its traditional applications for adults on extremities, pulse oximeters for fetal use and measurement at the retina are under active development.
Heart Sounds and Stethoscopes
Authors: Zhang Yuan-Ting , Chan Gregory , Zhang Xin-yu , Yip Lung
Published: April 2006

Heart sounds are the acoustic vibrations produced during the systole and diastole of the cardiac cycle. The art of evaluating the acoustic properties of heart sounds is known as heart auscultation. Heart auscultation has long been the most common technique for assessing the cardiac function of a patient. Conventional medical practice uses a mechanical stethoscope for auscultation. Often, the practitioners would need to rely on their hearing ability and their subjective judgement on the interpretation of the sounds. With the introduction of electronic stethoscopes, people are now hoping to measure and analyze heart sounds in a more objective manner. The rapid development in microchip technology in the past decade has resulted in electronic stethoscopes that are portable, robust to noise, and convenient to use. The future trend of electronic stethoscope would be a multifunctional auscultatory device with graphical display, wireless data transmission, real‐time signal processing for noise removal, selectable frequency response, etc. The newly developed electronic stethoscopes allow heart sounds to be digitally recorded and downloaded to a computer for analysis. Many of the computer‐based heart sound analysis techniques adopted by researchers, for example, wavelet transform and neural network, have already provided new insight into the diagnostic value of heart sound. The exploration of further techniques in the coming years would hopefully help to realize the full potential of heart sound auscultation as a tool the early detection of heart diseases.
Wireless Biomedical Sensing
Authors: Zhang Yuan-Ting , Lui Clifford K.C. , Luk B.L.
Published: April 2006

Wireless biomedical sensing is a technique that measures physiological signals of humans or animals from a distance without a wire connection. Its basic components are sensor/transducer, transmitter, and receiver with an electromagnetic wave as the most widely adopted transmission medium. The theory of wireless communication with an enhanced biomedical aspect is presented. The current status and future trends of this field are also discussed.
Telemedicine in Emergency Medical Services
Authors: Umpierrez Maria Fernanda Cabrera , Arredondo Maria Teresa
Published: April 2006

This chapter presents a new approach for the management of prehospital health emergencies: the integration of telemedicine services into an EMS community as a mean of improving the quality of care, accessibility, and cost‐effectiveness.

A reference architecture is specified based on a set of services that support the development of integrated prehospital health emergency management systems according to a proposed model.

The experimental work has been carried out with the collaboration of emergency medical services in Madrid that contributed to the initial design, the service provision, and the evaluation of the results. The evaluation of the proposed study cases has allowed determining the influence of the telemedicine services in the scenario of prehospital health emergency management.
Health Care Technology for the Developing World
Authors: Malkin Robert
Published: April 2006

To deliver health care effectively, even the most basic hospital must have functioning technology. Yet, in a developing world hospital, as much as 60% of the equipment does not work. Although it is tempting to blame the problem exclusively on the political or economic conditions of the third world, in fact, biomedical engineering has played a role in the failure to transfer the technological advances of the developed world to the population of the developing world. This article discusses the interaction of biomedical engineering and the developing world, as well as the tremendous opportunity that biomedical engineers have to contribute solutions to common third world problems.
EEG
‐Based Brain‐Computer Interface System
Authors: Pfurtscheller Gert , Graimann Bernhard , Neuper Christa
Published: April 2006

A brain computer interface (BCI) transforms electrophysiological signals originating from the human brain into commands that control devices or applications. In this way, a BCI provides a new nonmuscular communication channel, which can be extremely useful for people with severe neuromuscular disorders such as amyotrophic lateral sclerosis and brainstem stroke. The immediate goal of our current research is to provide these users with an opportunity to communicate with their environment. Future applications also include the field of multimedia and virtual reality.

Present day BCIs use a variety of electrophysiological signals such as slow cortical potentials, evoked potentials (P300), oscillatory activity recorded from scalp or subdural electrodes, and cortical neuronal activity recorded from implanted electrodes. EEG is by far the most frequently used input source, because it is readily available and noninvasive. The poor signal‐to‐noise ratio of scalp–recorded signals requires the application of advanced signal processing methods.

This article outlines and explains the current approaches and methods used in BCI research with emphasis on the signal processing part of the system, consisting of preprocessing, feature extraction, and classification. However, the success of a BCI depends not only on the methodologies applied, but also on the capability of the user to develop and maintain the skill to produce the brain patterns employed by the BCI. Therefore, the interaction between the BCI system and the user, in terms of adaptation and learning, is a challenging aspect of any BCI development and application.
Genomic Networks: Statistical Inference from Microarray Data
Authors: Zhou Xiaobo , Wang Xiaodong , Dougherty Edward R.
Published: April 2006

The huge amount of data provided by cDNA microarray measurements must be explored to answer fundamental questions about gene functions and their interdependence, and hopefully to provide answers to questions like what is the type of disease affecting the cells, or which genes have a strong influence on this disease? For given target genes, which genes have the strongest influences on them? Given a set of genes, how do they communicate with each other? The first question involves gene classification; the second question involves gene prediction; and the third question involves constructing genetic networks. In this article, we give a brief overview on modeling genetic networks and statistical inference of genetic networks based on microarray data.
Near‐Infrared Spectroscopic Imaging
Authors: Kotilahti Kalle , Kajava Timo , Noponen Tommi , Heino Jenni , Nissilä I. , Katila Toivo
Published: April 2006

Near‐infrared spectroscopic imaging is an emerging medical imaging modality based on the relatively low absorption of near‐infrared light in biological tissue. It allows noninvasive estimation and mapping of concentration changes of various chromophores (e.g., oxygenated and deoxygenated hemoglobin), which provide an indication of tissue physiology, so that the modality can be applied to functional studies of living tissue. In its simplest form, near‐infrared spectroscopic imaging can be carried out with inexpensive optoelectronic instrumentation, which measures the attenuation of light transferred through the object. More advanced time‐ and frequency‐domain instruments also measure the time the photons spend in tissue. Most tissue types scatter light strongly so that it is difficult to achieve useful spatial resolution and contrast with direct optical imaging like in x‐ray imaging. Therefore, the advanced imaging systems often use proper propagation models of diffuse light to aid the reconstruction of the optical properties inside the object. Potential applications of the modality include imaging of brain activation and hemorrhages, mammography, and monitoring of muscle oxygenation.
Artificial Blood
Authors: Sivan Sarit , Lotan Noah
Published: April 2006

The possibility of using human blood for transfusion is limited by requirements of blood‐typing, the danger of transmitting certain diseases, and a short shelf life of liquid blood. These limitations and the wide range of applications of blood substitutes have fueled a worldwide search for safe, effective, and universal blood substitute materials.

One major route to avoid the problems associated with blood (i.e., AIDS, Hepatitis, etc.) involves the use of isolated human hemoglobin (Hb) because of its high capacity of oxygen and hemocompatibility. However, cell‐free Hb has to be either molecularly modified or encapsulated in order to prevent its dissociation into dimers, decrease the high oxygen affinity, and increase the retention time in circulation. This route of research requires the use of specifically designed cross‐linker reagents necessary to modify the Hb protein.

With molecular engineering techniques, a new family of cross‐linking reagents was developed, based on nicotinamide‐adenine dinucleotide (NAD) derivatives. One of the reagents designed, namely oxidized beta‐NAD (o‐NAD), was reacted with deoxyHb to produce NAD‐derivatized hemoglobin (HbNAD). The latter was further polymerized to yield poly‐HbNAD.

Macroscopic properties of HbNAD and poly‐HbNAD were studied. From the results obtained, it is evident that poly‐HbNAD possesses a physiological oxygen‐carrying capacity and oncotic characteristics similar to whole blood. These properties make poly‐HbNAD a viable potential candidate as a resuscitation fluid.
Gene Expression Profiles, Nonlinear System Identification In
Authors: Korenberg Michael J.
Published: April 2006

The recent advent of the microarray has enabled simultaneous monitoring of the expression of thousands of genes, and with it have come vexing questions of how best to interpret the new wealth of data being gathered. Although many important uses have been made of this technology, such as for diagnosis, prediction of treatment response and clinical outcome, and prediction of metastatic status, we will focus attention on only these specific applications. It is clear that there is no consensus at present on the most effective methods for analysis of such gene expression data, and here we consider only some approaches that have forged a link between nonlinear system identification and construction of effective gene‐expression‐based class predictors. As we will discuss, one hallmark of these approaches is that they can produce effective predictors with considerably less training data than some statistically based prediction methods.