bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soft Tissue Scaffolds
Authors: Guan Jianjun , Stankus John J. , Wagner William R. 
Published: April 2006

AbstractThe effort to develop soft tissues is one of the most demanding and challenging applications in tissue engineering. Soft tissues such as myocardium, blood vessels, skeletal muscle, adipose tissue, and even cartilage often possess large volumes, have high cell densities, and can be mechanically active. 3‐D scaffolds that match the mechanical properties of the tissue that they are replacing are preferred for soft tissue engineering, because such materials might transmit mechanical forces to the developing tissue duringin vitroorin vivodevelopment. A well‐defined biodegradation rate is ideal so that host tissue can replace the scaffold and that stress can be transferred from the support scaffold to the new tissue over an appropriate time period. The scaffolds not only serve as a structural support, but also can play an important role in facilitating cell adhesion, growth, and vascularization throughout the scaffold both duringin vitrocell culture andin vivotissue regeneration.Currently used materials meeting these criteria are diverse and include entirely synthetic materials as well as those that are derived from natural sources, and formats that are continuous on a microscale (hydrogels) and those that have defined microporous architectures. Although natural materials have the inherent advantage of bioactivity, they also possess limitations when employed as soft tissue scaffolds that may be overcome with synthetics. Some limitations associated with natural materials include inducement of an immune response that can lead to rapid degradation as well as poor batch‐to‐batch consistencies. Synthetic polymers permit better control over chemical and physical properties leading to tunability in mechanical strength and degradation rate. Surface properties of synthetic materials can also be more easily modified for improved cell attachment or migration. Some disadvantages of synthetic tissue scaffolds consist of potential toxic degradation products and undesired inflammatory responses. In addition, fabrication methods can process materials into scaffolds of desired porosity, morphologies, and anisotropies. The focus of this article will provide a brief overview of the scaffold preparation, properties, and applications of soft tissue scaffolds.
Cartilage Scaffolds
Authors: Park Grace E. , Webster Thomas J. 
Published: April 2006

AbstractPerhaps due to its complex structure and composition, articular cartilage has been known to be one of the most common sources of pain and suffering in the body. Moreover, few biomaterials exist to treat the numerous problems associate cartilage decomposition and injury. This chapter will first present cartilage structure and properties useful in understanding cartilage problems and why it has been so difficult to repair cartilage damage. Then, this chapter will cover current technologies for articular cartilage repairs, emphasizing natural and synthetic materials. Lastly, this chapter will stress one promising approach for creating the next generation of cartilage scaffolds that involves nanotechnology. In this manner, this chapter will present a comprehensive view of cartilage structure, disease, and associate treatment methods.Many attempts to design better cartilage replacements are being attempted, from natural to synthetic materials. In the synthetic materials world, it seems that the best advances are being realized when attempting to mimic the unique nano‐ and micro‐structure of cartilage tissue, which includes mimicking the arrangement of collagen in each zone of cartilage tissue. It is through these attempts of manipulating chondrocyte function to regrow cartilage tissue that new materials may be found to heal this traditionally difficult anatomical area.
Batteries for Implantable Biomedical Applications
Authors: Holmes Curtis F. , Owens Boone B. 
Published: April 2006

AbstractBattery‐powered medical devices have been surgically implanted into the bodies of several million persons during the past one‐third of a century. Implantable devices have been used to treat an increasingly diverse number of conditions including cardiac arrhythmias, chronic pain, epilepsy, hearing loss, obesity, vision loss, and scoliosis. It is estimated that in the year 2004 over 500,000 heart pacemakers were implanted.A lithium primary battery powers the typical cardiac pacemaker. The reliability and the longevity of the pacemaker are determined by its design and manufacturing parameters, as well as therapy‐related variables. As battery failure results in a cessation of pacemaker output, the selection of the appropriate battery is an important step in the product development. A large number of battery designs have been developed to meet the unique requirements of implantable medical devices, ranging from the very‐low‐rate batteries that can power a pacemaker for many years, to the high‐rate batteries required for cardiac defibrillators.
Sensor Biocompatibility and Biofouling in Real‐Time Monitoring
Authors: Voskerician Gabriela , Anderson James 
Published: April 2006

AbstractThe development of reliable implantable electrochemical sensors for long‐term continuousin vivomonitoring of clinically important analytes remains one of the great challenges of biomedical engineering technology today. Although significant advances in the intravascular and subcutaneous biosensor development have been achieved, the biological response to the implantable biosensors continues to have a limiting impact on the performance and lifetime of such sensors, preventing their long‐term use in real‐time monitoring of critical analytes. Here, we examine the current status of research and development in this area, emphasizing the effect of the inflammatory and wound healing response on sensor biofouling. Also, the biocompatibility aspects of sensor implantation are discussed, as they are part of the inseparable dynamic continuum of biocompatibility and biofouling initiated by the presence of any foreign material/devicein vivo.
MRI Safety
Authors: Woods Terry O. 
Published: April 2006

Abstract
After the first MRI scanners were approved by the FDA in 1984, they were rapidly adopted by the clinical community and have become one of the most common imaging tools. The MR environment produces unique safety requirements for implants and other medical devices. The principal MR safety issues are magnetically induced force and torque, RF heating, and image artifact. This article defines MR characteristics that affect safety and outlines the potential hazards produced by medical devices in the MR environment. It also summarizes ASTM International test methods that can be used to evaluate the MR safety of medical devices and describes ongoing efforts in MR standards development.
Neuromuscular Coordination in Gait, EMG Analysis of
Authors: Pedotti Antonio , Frigo Carlo 
Published: April 2006

AbstractEMG signals are a neurological manifestation of the complex motor control mechanism. The relationship between EMG and its mechanical counterpart has been reviewed. Different ways to extract information from movement analysis are presented, and the role of advanced modeling procedures is discussed. The main concepts of multifactorial movement analysis are exemplified with reference to normal human walking.
Surface Electromyography (EMG) Signal Processing
Authors: Farina Dario 
Published: April 2006

AbstractAn overview of the common methods for processing surface electromyographic (EMG) signals is provided. The extraction of information from the surface EMG is based on the analysis of global properties of the interference signal or on the decomposition of the signal into single‐motor unit activities. Global analysis includes estimation of amplitude, power spectrum, average muscle fiber conduction velocity, and recurrence quantification. Single‐motor unit analysis is based on spatial filtering and spatial sampling. These techniques are reviewed and their limitations outlined. Finally, open issues in surface EMG signal processing are discussed.
Noise in Instrumentation
Authors: Chimeno Mireya Fernández , González Miguel Ángel García , Drechsler Manuel Vargas , Castro Juan José Ramos 
Published: April 2006

Abstract
Noise is an important factor to consider in the design of biomedical instrumentation systems. When calculating the total noise in an instrumentation system, it is necessary to consider the noise contributions of all elements: sensors, electronic systems, noise coming from external sources, etc. In this chapter, after an historical introduction, we define some mathematical properties of random processes useful for noise characterization; the different kinds of noise usually found in physical systems; the noise characteristics of sensors and electronic devices; and illustrate the methodology of analysis of complex systems from the point of view of biomedical applications when considering different noise sources. Finally, we provide an example for the noise analysis of a biomedical system.
Heart Rate Variability (HRV): Nonlinear HRV
Authors: Eyal Shulamit , Akselrod Solange 
Published: April 2006

AbstractThe cardiovascular system is considered to be a nonlinear system. Therefore, an effort exists to study its signals, such as heart rate and blood pressure, by applying nonlinear dynamics tools in addition to the commonly used linear tools. This chapter provides a brief introduction to the nonlinear field in conjunction with the main results obtained in studying heart rate variability. The main nonlinear methods discussed here are phase space portrait, surrogate data test for nonlinearity, and the two most commonly used parameters: the correlation dimension and the largest Lyapunov exponents. In order to complete the view on nonlinear analysis of the cardiovascular system, nonlinearity in blood pressure is presented briefly.
Electroporation
Authors: Miklavčič Damijan , Puc Marko 
Published: April 2006

Abstract
Electroporation is a transient phenomenon that increases permeability of the cell plasma membrane. In the state of high permeability, the plasma membrane allows ions and small and large molecules to be introduced into the cytoplasm, although the cell plasma membrane in its normal state represents a considerable barrier for them. Besides introduction of different substances to the cytoplasm, the permeabilized cell membrane allows cell fusion or insertion of proteins into cell membrane. Efficacy of electroporation and its applications strongly depends on parameters that can be divided into parameters of the electric field (i.e., pulse amplitude, pulse duration, pulse repetition frequency, number of pulses, and pulse shape), and parameters that define the state of cells, their surroundings, and cell geometry (i.e., temperature, osmotic pressure, cell size and shape, etc.). With properly chosen values of the electric field parameters, the process of electroporation is reversible and cells return into their normal physiological state. If these parameters exceed certain values (e.g., amplitude of pulses is too high or duration of pulses is too long), cells are irreversibly permeabilized and lose their viability.
Nanometer‐Scale Probes
Authors: Fletcher Dan 
Published: April 2006

Abstract
Scanning probe microscopes using nanometer‐scale probes enable imaging of materials with spatial resolution on the order of atoms. The most popular scanning probe techniques, including scanning tunneling microscopy (STM), scanning near‐field optical microscopy (SNOM), and atomic force microscopy (AFM), can be used to measure the topographical, electrical, optical, and mechanical properties of materials in environments including vacuum, air, and water. High spatial resolution is achieved by confining interactions between the probe and sample surface to the nanometer‐scale dimensions of the probe itself. As a result of their unique imaging and measurement capabilities, scanning probe microscopes using nanometer‐scale probes have become essential for high‐resolution characterization of biomaterials and biological molecules.
Scaffolds for Cell and Tissue Engineering
Authors: Jones Julian R. 
Published: April 2006

AbstractThe aim of tissue engineering is to combine the disciplines of engineering and biology to help the body's own regenerative mechanisms to repair diseased or damaged tissue to its original state and function. One strategy is to seed a patient's progenitor cells on a scaffold, which will act as a support and stimulus of tissue growth. The cells will lay down tissue in the shape of the scaffold and this biocomposite can be implanted into a defect with the scaffold dissolving as the tissue regenerates. Scaffold design is one of the important aspects of this strategy and will be discussed in this entry. The entry discusses the criteria for an ideal scaffold and the use of bioinert, bioresorble, and bioactive materials. The use of polymers, ceramics, glasses, and composites as scaffold materials and the processing techniques used to create tissue scaffolds are described and the advantages of using each material and each processing technique are discussed.
Tissue Engineering of Blood Vessels
Authors: Nerem Robert M. 
Published: April 2006

Abstract
A “holy grail” for cardiovascular researchers over the past half century has been the tissue engineering of a small‐diameter blood vessel substitute. There is a need for this substitute because blood vessel substitutes made from synthetic materials do not work in the small diameters required for coronary bypass surgery, and many patients do not have the native vessels normally used in such surgical procedures. Even in the replacement of larger blood vessels where synthetic grafts do work, it is hoped that an enhanced patency might be achieved through tissue engineering, i.e., a more biological approach.
Tissue‐Engineered Liver
Authors: Berthiaume François , Yarmush Martin L. 
Published: April 2006

Abstract
The severe donor liver shortage, high cost, and complexity of orthotopic liver transplantation have prompted the search for alternative treatment strategies for end‐stage liver disease, which would require less donor material, be cheaper, and be less invasive. Hepatic tissue engineering encompasses several approaches to develop adjunct internal liver support methods, such as hepatocyte transplantation and implantable hepatocyte‐based devices, as well as temporary extracorporeal liver support techniques, such as bioartificial liver assist devices. As hepatocytes are highly sensitive to various environmental parameters, such as culture medium, substrate composition and topology, the presence or absence of contacts with other cells, and physical forces, it is important to first develop a small‐scale liver functional unit that performs stable long‐term liver‐specific functions. This unit forms the basis of larger devices that contain sufficient numbers of cells to have a therapeutic benefit. The major hurdles in the scale‐up of liver cell‐based assist devices is the procurement of a sufficient number of cells, and the engineering of devices that provide good oxygen and nutrient transport to the cells. These remaining challenges must be resolved in order to develop the next generation of implantable and extracorporeal devices for adjunct or temporary liver assist.
Tissue‐Engineered Peripheral Nerve
Authors: Leach Jennie B. 
Published: April 2006

AbstractPeripheral nerves can be injured by a variety of mechanisms but can regenerate on their own if the injury is not extensive. Nerve grafts, the current standard of surgical care for repairing large nerve gaps, are successful, but they can be associated with several major drawbacks. To overcome these disadvantages, researchers are designing “off‐the‐shelf” nerve guide implants; thus, a multidisciplinary effort is underway to engineer nerve repair through a deeper understanding of the dynamic cell–cell and cell–environment interactions that occur during regeneration. This entry, which focuses on literature published in the last 5 years, first emphasizes new nerve guide designs that have been demonstrated to improve functional regenerationin vivo. The second section reviews studies that have deepened our understanding ofin vitroandin vivoneural regenerative responses via new biomaterials technologies and imaging techniques. These critical advancements in peripheral nerve tissue engineering provide templates for future mechanistic studies and improved strategies to aid functional regenerationin vivo.
Myoelectric Signal Processing
Authors: Morin Evelyn 
Published: April 2006

AbstractThe myoelectric signal or electromyogram (EMG) is recorded during voluntary contraction of skeletal muscle. Surface EMG (sEMG) is detected at the skin surface using electrodes attached to the skin over the muscle of interest. The resultant signal varies randomly about a zero mean value. This signal can be processed to provide information concerning the physiological and the biomechanical state of the muscle. This article covers two major processing paradigms—amplitude estimation and spectral analysis. sEMG amplitude estimation involves estimating the time‐varying standard deviation of the signal. Amplitude estimators from the simple integrated EMG to more complicated estimators, involving prewhitening filters, multiple channels of sEMG, and adaptive smoothing, are covered. Spectral analysis of sEMG is done to characterize the signal in the frequency domain, Fourier analysis of stationary sEMG, recorded during isometric, isotonic contractions, and time‐frequency analysis of nonstationary sEMG recorded during dynamic contractions, are discussed.
Myoelectric Manifestations of Muscle Fatigue
Authors: Merletti R. , Farina D. 
Published: April 2006

Abstract
Among physiologists, “fatigue” has been defined in different ways. One definition is the “failure to maintain the required or expected force.” This chapter examines muscle fatigue. After the introduction, the next section examines sites of neuromuscular fatigue. Equations that quantify fatigue are given. A later section discusses myoelectric manifestations of muscle fatigue. Finally, the chapter concludes with estimates of EMG variables and fatigue indexes.
Muscle Pain
Authors: Graven-Nielsen Thomas , Arendt-Nielsen Lars 
Published: April 2006

AbstractAcute and chronic pain originating from deep somatic structures represent a major part of complaints in patients seeking health services. In a large survey, it was found that approximately 50% of the respondents had experienced pain or unpleasantness originating from musculoskeletal structures within two weeks before the interview. Moreover, musculoskeletal pain complaints were the main reason for 10% of all visits to a clinical practice in the United States. Thus, it is generally accepted that pain from deep tissues constitutes a special diagnostic and therapeutic challenge, and insights into the peripheral and central neurobiological mechanisms are necessary to improve diagnosis and management strategies.
Homecare
Authors: Tilford Arthur R. 
Published: April 2006

Abstract
Until now, the “at best” or near “best” homecare environment has been so costly that few, except those with nearly unlimited financial resources, could demand it. Even those with unlimited funds were still at the mercy of the established medical facility when laboratory work was required or extensive surgery was indicated. However, with the dramatic surge of advancements in communications, computer technology, and biomedical products including materials, the homecare environment can reach the level of professionalism found only within the established medical facility or hospital.
Telesurgery
Authors: Sood Sanjay P. 
Published: April 2006

AbstractMedicine — inherently a forward‐looking domain of high social relevance — banks heavily upon technology for empowering clinicians and patients. Almost all sensational clinical developments are presumably the gifts of synergistic efforts of an extraordinary fusion of clinicians, engineers, and researchers. This synergy has transformed medicine into one of those few domains where technology is exploited to the maximum. Boundaries between medicine and technology are no longer distinct and definite. The role of engineers at the rear end is soaring, and someone has rightly said that the future of medicine is technology. Technologically fertile medical procedures like minimally invasive surgery have revolutionized surgical practices. Very mechanically, robotics has not only walked into medicine but has also secured a commanding position in critical procedures like surgeries. Besides fueling the basic developments, robotic surgery has enhanced precision, performance, and outcome. Continuing this technological march toward clinical excellence, clinicians, engineers, and researchers, in their stride, have been able to surmount an even more exciting technology calledtelesurgery. This novel technology enables surgeons to perform surgical procedures over a distance. Telesurgery is an umbrella term that implies the use of telemedicine in surgery. This extension has virtually ended the tyranny of geography as far as the duo of a surgeon and a patient is concerned. Telesurgery is a conglomerate of other state‐of‐the‐art technologies like virtual reality, haptics, 3‐dimensional simulation techniques, and networking technologies. Concepts like telementoring, teleproctoring, telepresence, and telerobotics fall under its domain. Consistent efforts by associated professionals are helping to get over initial issues and challenges to enable telesurgery to reach a level of application, at large.
Robotic Rehabilitation Therapy
Authors: Krebs Hermano I. , Hogan Neville 
Published: April 2006

AbstractThe demand for rehabilitation services is growing apace with the graying of the population, with the number of senior citizens 65 years of age and older projected to increase by 88% in the coming years. With this increase in the number of senior citizens comes increased incidence of age‐related pathologies including cerebral vascular accident (stroke). This situation creates both a need and an opportunity to deploy technologies such as robotics to assist recovery. In this chapter, the authors focus on the use of robotics to aid recovery after stroke, but the knowledge and know‐how may apply similarly to other diseases and afflictions. The authors focus solely on robots that support and enhance the productivity of clinicians in their efforts to facilitate a disabled individual's recovery. An overview of existing rehabilitation robots for the upper and lower extremity, of technology limitations, of design choices, and of clinical results is presented. The focus of the remainder of the chapter is on clinical results and on the biology of neuro‐recovery. This new class of interactive robotic devices, together with the understanding of its potentials and limitations, are poised to strongly influence how rehabilitation medicine will be practiced in the twenty‐first century.
Orthopedic Bone Cement
Authors: Deb Sanjukta 
Published: April 2006

Abstract
Acrylic bone cement has a distinctive place in the domain of synthetic biomaterials. It is one of the earliest synthetic polymers to be used in the body and is the most widely used materials in the anchoring of prosthesis to bone in a cemented arthroplasty. However, the cement is not without its own drawbacks and has often been related to the failure of a clinical arthroplasty. This article provides an understanding of the chemistry, composition, physical and mechanical properties, risks and failure mechanisms, improvements, and current trends of acrylic bone cements.