bluuebunny/crossref_metadata_2025_split huggingface dataset:
Haptic Interaction in Medical Virtual Environments
Authors: Nikolakis Georgios , Koutsonanos Dimitrios , Moustakas Konstantinos , Daras Petros , Tzovaras Dimitrios , Strintzis Michael G. 
Published: April 2006

AbstractIn recent years, there has been a growing interest in developing force feedback interfaces that allow people to access information presented in 3D virtual reality environments (VEs). One of the major application fields is medicine. Several cases exist where standard medical treatment cannot be applied to patients for several reasons, such as distance from hospital, lack of specialized doctor, and lack of medical equipment. The use of haptic‐enabled virtual environments provides an alternative solution in a variety of such cases, thus enabling assessment and treatment of patients. Furthermore, haptic‐enabled virtual environments provide a nonhazardous means of treatment for several disorders like phobia treatment, where the patient has to be exposed to the phobia object. Training of disabled people, like the visually impaired, is another important application of haptic‐enabled VEs. This chapter presents an extended description of haptic virtual environments and the major methodologies and techniques used in medical applications. Further, it demonstrates indicatively a number of applications in order to illustrate the applicability of VEs in several areas of medical treatment and training.
Biomedical Products, International Standards for
Authors: Marlowe Donald E. 
Published: April 2006

Abstract
International standards for biomedical products have become the coin‐of‐the‐realm in the discussions among governments, product manufacturers, and users. These stakeholders use these documents to allow a supplier and user of goods or services to describe to each other what is being supplied and to ensure or improve public safety and health. What are international standards? This article will discuss the topic at several levels and identify the sources of these standard for biomedical products.
Intestinal Motility
Authors: Garcia-Casado J. , Martinez-de-Juan J.L. , Ponce J.L. 
Published: April 2006

Abstract
Intestinal motility, i.e., gut mechanical activity, is associated with the functions of mixture and transport performed by the small bowel. Its information is of great interest for the diagnosis of such pathologies as intestinal ischemia, irritable bowel syndrome, paralytic ileum, or intestinal obstruction. Nevertheless, the difficult access to this portion of digestive tract and its length and irregular distribution in the abdominal cavity complicate its registration and study.
The measurement of intestinal mechanical activity has traditionally been carried out by manometric techniques. However, physiologic and technical problems derived from the use of these techniques raise doubts about its clinical applications. As there is a myoelectric activity generated by intestinal smooth muscle associated with its mechanical contraction, myoelectric techniques emerge as an alternative solution to the problem of monitoring intestinal motility.
Biomedical engineering proposes different techniques of analysis and registration in response to the necessity of studying these myoelectrical signals. Concretely, spectral analysis and analysis in the time‐frequency domain provide objective parameters to quantify small bowel activity. Even so, registering intestinal myoelectric activity requires surgical intervention for electrodes’ implantation in bowel serosa.
Nowadays, the trend of research studies is directed to the noninvasive measurement of intestinal motor activity by placing sensors on the external abdominal wall: microphones, magnetic flux detectors, or contact electrodes. If technological development of these techniques is achieved, new diagnostic tools of great interest for gastroenterology would be available.
Ischemia
Authors: Ferrero José M. , Ferrero Ángel , Trénor Beatriz , Montilla Fulgencio , Saiz Javier , Rodríguez Blanca 
Published: April 2006

AbstractThe word “ischemia” refers to a situation in which the blood flow is insufficient to meet the metabolic demands of a tissue or an organ. Ischemia is caused by the total or partial occlusion of an artery. It can create a life‐threatening situation, and the vascular diseases related to ischemia are among the first causes of mortality and morbidity in the world. In its acute form, ischemia is usually originated by the rupture of a vulnerable atherosclerotic plaque, by the lodge of an embolus in an artery, or less frequently, by an artery spasm. On the contrary, chronic ischemia is related to stable atherosclerotic plaques that narrow the artery lumen.Ischemia can affect different organs or tissues, but its most harmful (and frequent) forms are myocardial and cerebral ischemia. Limb, mesenteric, and renal ischemia are also clinically significant. Different techniques are used to diagnose ischemia, including analysis of bioelectric signals (electrocardiogram), ultrasonic techniques (ultrasonography and doppler‐echography), angiography, magnetic resonance imaging (MRI ), or computerized axial tomography (CAT scan). In the treatment of ischemia, percutaneous interventions (angioplasty), together with stent placement, are used in addition to surgery and pharmacological therapies.Acute myocardial ischemia is a life‐threatening form of ischemia. It causes different metabolic alterations that lead to changes in ionic concentrations, action potentials, and overall electrical activity of the heart, setting the stage for malignant arrhythmias to occur (e.g., ventricular fibrillation) and posing a critical threat on the life of the patient.
Intelligent Mobility Aids
Authors: Simpson Richard C. , Rentschler Andrew 
Published: April 2006

AbstractIndependent mobility is a critical component of a person's quality of life. Although many persons with mobility impairments can be accommodated by traditional mobility aids (e.g., canes, wheelchairs, scooters, and walkers), a segment of the disabled community exists who find it difficult or impossible to use traditional mobility aids independently. This population includes, but is not limited to, persons with low vision, visual field neglect, spasticity, tremors, and cognitive deficits. To accommodate this population, researchers have used technologies originally developed for mobile robots to create intelligent mobility aids. These devices typically consist of either a traditional mobility aid to which a computer and a collection of sensors have been added or a mobile robot base to which a seat and/or handlebars have been attached. In this article, we summarize research that has been conducted to date on intelligent mobility aids based on power wheelchairs and wheeled walkers (i.e., rollators).
Multiphoton Microscopy
Authors: Diaspro Alberto , Caorsi Valentina , Bianchini Paolo , Chirico Giuseppe , Usai Cesare 
Published: April 2006

Abstract
Nowadays, optical microscopy has evolved into three‐dimensional (3‐D) (x‐y‐z) and four‐dimensional (4‐D) (x‐y‐z‐t) analyses allowing researchers to probe even deeper into the intricate mechanisms of living systems. Within this scenario, two‐photon and multiphoton excitation (TPE, MPE) microscopy are probably the most relevant advancement in fluorescence optical microscopy since the introduction of confocal imaging in the 1980s. MPE microscopy has a 3‐D intrinsic ability coupled with almost five other interesting capabilities, namely: (1) MPE greatly reduces photo‐interactions and allows imaging of living specimens on long time periods; (2) MPE operates in a high‐sensitivity background‐free acquisition scheme; (3) MPE microscopy can image turbid and thick specimens down to a depth of a few hundred micrometers; (4) MPE allows simultaneous excitation of different fluorescent molecules reducing colocalization errors; and (5) MPE can be used to prime photochemical reactions within a subfemtoliter volume inside solutions, cells, and tissues. Besides, MPE fluorescence microscopy is not only revolutionary in its ability to provide the above‐mentioned features, together with other practical advantages, but also in its elegance and effectiveness of application of quantum physics. The MPE story, more specifically TPE, dates back to 1931, and its roots are in the theory originally developed by Maria Göppert‐Mayer that brought, passing through the scanning nonlinear microscope developed by Colin Sheppard in Oxford at the end of the 1970s, to the revolutionary and successful results on biological samples obtained at the Watt Webb laboratories by Winfried Denk and colleagues at the beginning of the 1990s. MPE can be considered a young microscopical technique. In general, it is more convenient to consider TPE, for the sake of simplicity.
Muscle, Skeletal
Authors: Felici Francesco , Sbriccoli Paola 
Published: April 2006

AbstractSkeletal muscle is the actuator of motor programs generated by the central nervous system (CNS). The CNS fine‐tuning of muscles’ activity makes very complex motor patterns appear extremely simple and smooth. This chapter will provide a synthetic summary of the most up‐to‐date knowledge in the field of muscle contractile properties and the relationships between muscle structure and function. To date, despite the large amount of information concerning muscle structure and function, the equations describing muscle mechanical behavior are yet to be fully defined, which can be largely attributed to the fact that the real muscle exerts its action along with other mechanical structures. Muscle forces must be transmitted to bones through the muscle‐tendon junction and the tendon. The mechanical properties of such elements may influence muscle force exertion and its mechanics, thus the necessity for developing models of muscle mechanics that are continuously updated with new results provided by the experiments. However, to respect the boundaries of this section, we will not refer either to CNS control of muscle activity or to the mechanical properties of noncontractile elements. Also, the energetic aspects of muscle contraction will not be discussed in this chapter.
Oculomotor Control
Authors: Hung George K. 
Published: April 2006

Abstract
The main aim of oculomotor control is to drive the eyes in a rapid, stable, and coordinated fashion to provide accurate bifixation of targets in space. Eye movement measurements have provided quantitative assessments of these control processes. Indeed, advances in eye movement measurement technology and cortical imaging techniques will continue to provide deeper insights into neurological processes that guide oculomotor responses under both normal and disease conditions.
Optoelectronics
Authors: Stroscio Michael A. , Dutta Mitra 
Published: April 2006

AbstractOptoelectronics embodies a broad range of scientific and technological knowledge and enables the design and application of devices with both optical and electronic inputs and outputs. Accordingly, optoelectronic devices operate in a greater variety of modes and are more functional than their purely electronic counterparts. This rich variety of operational modes has had an enormous positive influence on lightwave communication systems, on devices for light‐to‐electric energy conversion, and on optoelectronics‐based switching and logic elements. These devices also underlie many innovations such as bar‐code pricing, laser printers, laser readers, etc. Optoelectronic devices have unique abilities to monitor the amplitudes and temporal characteristics of radiation in the ultraviolet (UV), visible, and infrared (IR) regions of the electromagnetic spectrum. Moreover, optoelectronic devices are capable of producing radiation spanning the UV, visible, and IR spectra at ever‐increasing power levels and with temporal characteristics that may be controlled with sub‐nanosecond precision. These novel capabilities and expanded levels of functionality will continue to open many avenues for biomedical applications, thereby expanding the list of current applications such as laser surgery. In many cases, the optical properties of these devices are determined by the electronic properties of the materials used in the construction of the active components of an optoelectronic device or system. Optoelectronic devices span the range from simple devices, such as a detector of light based on the photoelectric effect discovered by Albert Einstein (1879–1955) in 1905, to modern monolithically integrated semiconductor heterostructure devices incorporating miniature lasers, photodiodes, and electronic components, such as amplifiers, all grown on the same semiconductor substrate. These devices generally function for the purpose of or by employing techniques for the processing of optical and electronic signals. The variety of optoelectronic devices has increased enormously in the last few decades because of advances in the materials science underlying the growth, fabrication, and production of components for optoelectronic devices and systems. The rich and growing diversity of optoelectronic devices is making possible continuously expanding applications of optoelectronics in biomedical engineering.
Nanoparticles in Biomedical Photonics
Authors: Chithrani B. Devika , Chan Warren C. W. 
Published: April 2006

Abstract
Photonics refers to the studies or applications of light or photons, which includes the study and design of lasers, the applications of fluorophores in diagnostics, or the use of light‐scattering technologies. Photonics is a broad research field. In this chapter, we will focus on an emerging subdiscipline of photonics, which is the development of gold nanostructures for biomedical applications. Gold nanostructures are of interest to the photonics community because these materials have interesting tunable optical properties. Biomedical engineers are exploiting these properties for development of new diagnostics, drug delivery, and therapeutics.
Piezoelectric Devices in Biomedical Applications
Authors: Lewin Peter A. , Reid John M. 
Published: April 2006

Abstract
We focus on piezoelectric devices in biomedical applications only. The devices are classified depending on their electrical, mechanical, or hybrid output signal. The hybrid device operates in a reversible mode and can generate both electrical and mechanical signals at its terminals. Electrical output piezoelectric sensors include frequency generators, force and pressure measurement sensors, accelerometers, velocity and displacement sensors, and receivers such as microphones. Linear scanning motors and acoustic wave generators fall into the category of mechanical output devices or actuators. Also, acoustic wave generators, such as lithotripters, loudspeakers, and ultrasonic therapy applicators, can be considered as actuators. Medical ultrasonic transducers used to generate images of internal organs of the body can be defined as hybrid or combination devices, as they act as both actuators and receivers producing an electrical signal proportional to the input mechanical stimulus at their terminals, and conversely, a mechanical displacement amplitude proportional to the electrical excitation.
Proteomics
Authors: Alterovitz Gil , Afkhami Ehsan , Barillari Joseph , Ramoni Marco 
Published: April 2006

AbstractResearch in proteomics involves studying the structure, expression, localization, interactions, and cellular roles of all proteins within a particular organism or subcomponent thereof. Researchers coined the term “proteomics” in the early 1990s to describe a new approach to studying proteins, focusing on high‐throughput analyses and on breadth rather than depth. Proteomics researchers aim to use experimental techniques that trade accuracy for volume in order to build up a complete picture of the function of large groups of proteins. Key research in the field focuses on the development of new high‐throughput techniques and the computational machinery needed to analyze the data those techniques produce.
Pulmonary Mechanics
Authors: Bates Jason H.T. 
Published: April 2006

AbstractPulmonary mechanics deals with relationships among gas pressures, flows, and volumes in the lung. Assessing pulmonary mechanics is important for diagnosing lung disease and for following the progress of therapy. Clinical assessment of lung function is usually based on empirical quantities derived from recordings of forceably exhaled volume, and from measurements made in the body plethysmograph. In the research laboratory, pulmonary mechanics are frequently assessed with system identification techniques to determine quantities such as input impedance. These quantities are interpreted using physiologically based mathematical models.
Pulmonary Medicine, Applications of Biomedical Engineering to
Authors: Cherniack Neil S. , Longobardo Guy S. 
Published: April 2006

Abstract
Pulmonary medicine is concerned with preventing and treating diseases that affect the lungs as well as the entire respiratory system, i.e., the muscles that create the pressures needed to bring air into and out of the lungs, as well as the sensors and the respiratory neurons that set the level and pattern of breathing. The respiratory system provides oxygen for body metabolic needs and rapidly removes in the form of carbon dioxide the acids produced as a result of metabolic processes. It is functionally and structurally linked to other systems such as the cardiovascular and renal system, which also act to maintain tissue oxygenation and acid–base balance.
The lung is the primary interface of the respiratory system with the outside world, and because breathing involves the daily exchange of almost 7500 L of air containing microorganisms and injurious particles, the lung is the part of the respiratory system most commonly affected by disease. However, disease can affect any part of the respiratory system. Unchecked, some respiratory diseases lead to respiratory failure characterized by hypoxia and elevated levels of carbon dioxide. In addition, intermittent hypoxia and hypercapnia can occur during sleep as a consequence of episodic upper airway obstruction.
Bioengineering applies the basic scientific approaches of biology, physics, chemistry, and engineering to the medicine of the respiratory system to develop mathematical models, which describe and explain pathophysiological processes and develop instruments and diagnostic processes to treat or support the respiratory system.
Ultrasonic Imaging
Authors: Insana Michael F. 
Published: April 2006

AbstractThe basic principles of ultrasonic B‐mode imaging are summarized. Tissue features that generate contrast and system features that control image quality are reviewed in the context of breast cancer imaging. Approaches to signal modeling, including B‐mode and Doppler techniques, are reviewed to guide methodological design and clinical evaluation. The article concludes with a brief summary of current research.
Ultrasonic Transducers for Medical Imaging
Authors: Lockwood Geoffery R. 
Published: April 2006

AbstractThe performance of modern ultrasound imaging systems is primarily determined by the characteristics of the ultrasound transducer. Early imaging systems were based on single‐element transducers. These transducers had a fixed focal distance and had to be mechanically scanned to create an image. The systems were cumbersome to use, and the image quality was relatively poor. Much of the success of modern ultrasound imaging can be attributed to the development of efficient transducer arrays. The ultrasound beam produced by an array can be electronically steered and focused. Electronic steering avoids the need to mechanically scan the transducer, whereas electronic focusing provides improved resolution over a large imaging depth. Since transducer arrays were first introduced in the late 1970s, there has been a steady improvement in the efficiency and resolution of arrays. Transducer arrays are now available in a variety of geometries and operating frequencies, each optimized for a particular imaging application. As new transducer materials and improved fabrication techniques have become available, there has been a corresponding improvement in the quality of the ultrasound images. The pace of this development has not slowed, and improvements in ultrasound imaging can be expected for many years to come.
Viscoelasticity
Authors: Bilston Lynne E. 
Published: April 2006

AbstractViscoelastic materials, which combine viscous and elastic characteristics, are abundant in the body. The theory of viscoelasticity is widely used to describe their response to mechanical loading, for both physiological and injurious levels of loading. Most viscoelastic materials are nonlinearly viscoelastic for strains of practical interest. This requires the use of nonlinear viscoelastic theories, of which quasi‐linear viscoelasticity is the most common. Structural viscoelastic models, which attempt to replicate the multiphase structure of soft biological tissues, have also been developed and are increasing in flexibility and complexity to better match the observed mechanical behavior of soft tissues. Future challenges in viscoelastic modeling of human body tissues include determiningin vivoproperties and developing computationally efficient models that can still capture the complex nonlinear viscoelastic behavior of these tissues.
Wide Area Networks
Authors: Yao Wenbing , Loo Kok-Keong 
Published: April 2006

Abstract
In this chapter, a general introduction to wide area networks (WANs) and the relevant popular WAN technologies are given. The definition of WAN, the development of WAN technologies, the international organizations that have important impact on the development of WAN technologies, and the classification of WANs are introduced. The broad‐band access technologies for WAN, including the xDSL and Cable Modem, are summarized. ISDN as a typical example of circuit‐switched WAN is also briefly explained. In the last section, the WAN transport technologies section, three key technologies, X.25, frame relay, and ATM, are discussed.
Magnetic Resonance Current Density Imaging
Authors: Eyüboğlu B. Murat 
Published: April 2006

Abstract
Magnetic resonance current density imaging (MRCDI) is an emerging modality that is used to image current density distribution created by an externally applied current to a conductor that contains nuclear magnetic resonance (NMR) active nuclei. Distribution of externally applied electrical current inside the body provides important information in many biomedical engineering applications: such as improvement of electrical stimulation devices by optimal electrode designs for electrosurgery, defibrillation, and cardiac pacing; optimization of defibrillation efficacy; determination of electrode geometry and current level in cancer treatment; electroconvulsive therapy; and noninvasive localization of epileptic spikes in the brain and determination of fatal current levels. Knowledge of current density distribution originating from a pair of electrodes can be used to calculate lead‐sensitivity maps of biopotential recording electrodes, and to improve the sensivity matrix used in electrical impedance tomography (EIT) image reconstruction. Finally, accurate measurement of current density distribution leads to high‐resolution conductivity imaging.