bluuebunny/crossref_metadata_2025_split huggingface dataset:
NeurologicalEEGMonitors: A Review
Authors: Gharieb R. R. , Thakor N. V. 
Published: April 2006

AbstractThis article presents a brief review of neurological monitors. Neurological monitors mainly utilize brain wave activity, namely, the electroencephalogram (EEG). The constituent components of the neurological monitor are the electrodes, amplifiers, analog‐to‐digital converter (ADC), and the monitoring display. Moreover, the monitor should provide digital storage and a readout of the ongoing EEG. Neurological diagnostic monitoring is accomplished using quantitative EEG analysis for assessment of the ongoing brain activity. The software of the monitor is designed to acquire and filter the raw EEG signal, remove artifacts, process the artifact‐free EEG signal, and utilize quantitative analysis of EEG to interpret neurological status of the brain. As such, the EEG monitors can be classified into two main categories based on their use in data monitoring and display and their use in providing quantitative EEG measures derived for assessment and tracking of the brain electrical activity in disease and brain injury. Several quantitative EEG (qEEG) analysis methods used in the more advanced diagnostic devices are reviewed. The article conclude by describing the most common specifications of an optimized monitor.
Electrocardiography, Computers in
Authors: Nazeran Homer 
Published: April 2006

Abstract
This article starts off with an attempt to present a distilled overview of the origin of bioelectric signals in general, and the electorcardiographic signal in particular. This overview sets the basis to briefly describe the cardiac vector and its projection along specific directions (leads) providing the surface ECG recordings and review the basic instrumentation necessary to record these signals. A detailed description of a high end computer‐based 12 lead clinical ECG acquisition and analysis system provides an example to appreciate the role of computers in diagnostic electrocardiography. An overview of the role of computers in high resolution electrocardiography (body surface potential mapping) and other ECG‐based diagnostic devices then follows. A brief introduction to computer‐based ECG monitoring systems and a block diagram description of a QRS detection algorithm illustrate how computer programming serves as a basis to detect cardiac arrhythmias. The article ends with a web‐based ECG telemonitoring system as an example.
Electroencephalography
Authors: Sherman David , Walterspacher Dirk 
Published: April 2006

AbstractThe following section will give an overview of the electroencephalogram (EEG), its origin, and its validity for diagnosis in clinical use. Since Berger demonstrated in 1929 that the activity of the brain can be measured using external electrodes placed directly on the intact skull, the EEG has been used to study functional states of the brain. Although the EEG signal is the most common indicator for brain injuries and functional brain disturbances, the complicated underlying process, creating the signal, is still not well understood.The section is organized as follows. The biophysical basis of the origin of the EEG signal is described first, followed by EEG recordings and classification. Afterward, the validity and scientific basis for using the EEG signal as a tool for studying brain function and dysfunction is presented. Finally, logistical and technical considerations as they have to be made in measuring and analyzing biomedical signals are mentioned.
Electroneurography
Authors: Sinkjær Thomas , Yoshida Ken , Jensen Winnie , Schnabel Veit 
Published: April 2006

AbstractAn essential part in the success of recording peripheral nerve signals is the neural interface. This article gives the theoretical basis of how the action potential in a nerve is generated, and how this, in turn, results in a change in the electric field in the extracellular space. These potentials can be detected using neural interfaces (electrodes) in mono‐ to multipolar recording configurations to maximize the neural signal detected and minimize the noise pickup. These configurations are discussed along with a characterization of the recorded electroneurogram (ENG). Whether the ENG signals are recorded from extrafascicular or intrafascicular neural interfaces, it can be seen that ENGs are low amplitude signals and require amplification of between 1000X and 100,000X to bring the amplitude into the ∼ 1 V range. Electrode impedance models are derived to illustrate how the common mode rejection ratio (CMRR) of an ENG amplifier is influenced by frequency depended impedances.Peripheral neural electrodes can be grouped according to the way that they interface with the peripheral neural tissue. The three main groups are regenerating, intraneural, and extraneural electrodes. Common for all electrode interfaces presented here are that they record the extracellular potential from one or many peripheral nerve axons simultaneously.This article concludes with a section on recent studies performed with chronically implanted nerve cuffs in animal models and disabled human subjects. Exmples are presented of the potential value of peripheral nerve recordings to furnish sensory information for feedback control in fully implantable neuroprostehsis systems.
Electrophoresis
Authors: Brewer John M. 
Published: April 2006

Abstract
Electrophoresis involves application of an electric field to solutions of ions, causing them to move. The aim is to separate charged molecules, particularly proteins and polynucleotides. Better separation may result from use of electrophoretic characteristics of different small ions (mobilities), from use of materials employed to prevent convective disturbances (support media), or higher voltages. Successive electrophoresis in two directions under different conditions on sheets of support media can resolve thousands of proteins. Electrophoresis in the presence of an ionic detergent is used to obtain protein subunit molecular weights. Electrophoretic separation of polynucleotides varying in length by one nucleotide is the basis of DNA sequencing. Clinical use of electrophoresis is for diagnostic purposes.
Electroretinography
Authors: Holder Graham E. 
Published: April 2006

Abstract
Electroretinography (ERG) objectively evaluates the function of the photoreceptor and inner nuclear layers of the retina by measuring the small electrical signals generated in response to controlled flashes of light. The stimuli are delivered via a Ganzfeld bowl, an integrating sphere, and are recorded using small electrodes in contact with the surface of the eye.
Manipulation of the adaptive state of the eye and variation in stimulus parameters enables separation of the function of different cell types and layers. In general, responses obtained under dark adaptation (scotopic) are rod‐dominated and those under light adapted conditions (photopic) are cone dominated. The function of the macula, the cone‐rich central area of the retina, can be quantified with the pattern electroretinogram (PERG, the response of the retina to a black and white reversing checkerboard or grating), which also, in relation to its inner retinal origins, enables retinal ganglion cell function directly to be ascertained. Assessment of central retinal cones can also be performed with multi‐focal ERG, which additionally provides spatial information.
The basics of recording electroretinographic signals are discussed, and the importance of performing all tests to published international standards is noted. An overview is presented of the value of the tests to the diagnosis and management of the patient.
Environmental Control
Authors: Anson Denis 
Published: April 2006

Abstract
Electronic aids to daily living (EADLs) are devices that can be used to control electrical devices in the client's environment. Before 1998, these devices were generally known by the shorter term, “Environmental Control Unit” (ECU). Technically, this term should be reserved for furnace thermostats and similar controls. The more generic EADL applies to control of lighting and temperature, but also applies to control of radios, televisions, telephones, and other electrical and electronic devices in the environment of the client.
These systems all contain some method for the user to provide input to the EADL, some means of determining the current state of the device to be controlled (although this is often visual inspection of the device itself, since EADLs are generally thought of as being applied to the immediate environment), and a means of exerting control over the targeted device. The degree and generalization of control differs among various EADL systems. These systems may provide a means of switching power to the target device, of controlling the features of an external device, or may subsume an external device to provide enhanced control internally.
Esophageal Manometry
Authors: Velanovich Vic 
Published: April 2006

Abstract
Esophageal manometry measures pressures of the intraesophageal space. These pressures are reflective of the function of the esophageal musculature. The structures primarily assessed are the upper esophageal sphincter, the esophageal body, and the lower esophageal sphincter. The device measures pressures through either a water‐perfused or solid‐state catheter connected to a pressure reading instrument. The device measures lower esophageal sphincter pressure, length, and relaxation; esophageal body contractions, coordination, peristalsis, and peristaltic pressure amplitudes; and upper esophageal pressure and relaxation. Esophageal manometry is useful in the assessment of dysphagia, gastroesophageal reflux disease, generalized diseases with esophageal manifestations, and the exclude esophageal disease in patients with anorexia nervosa.
Fetal Monitoring
Authors: Neuman Michael R. 
Published: April 2006

Abstract
Fetal monitoring is a special type of electronic patient monitoring aimed at obtaining a record of vital physiologic functions during pregnancy and birth. Such monitoring is applied in assessing the progress of pregnancy and labor, and it can identify conditions that concern the clinician caring for the patient. These nonreassuring recordings can lead to special considerations in caring for the pregnant patient and in managing her labor. Although these recordings are no longer considered to be definitive in identifying most forms of fetal distress, they can help to reassure patient and clinician that the fetus is able to withstand the physiologic stress of labor and delivery. The technology is also useful in assessing high‐risk pregnancies, which in most cases, is only reassuring as opposed to giving a definitive diagnosis. Although this technology is now recognized to have diagnostic limitations, it is still frequently used in the hospital and clinics as an adjunct to other diagnostic evaluations.
Fiber Optics in Medicine
Authors: Modell Mark D. , Perelman Lev T. 
Published: April 2006

Abstract
The goal of this article is to give the reader basic tools necessary to understand principles of biomedical fiber optics and its applications. In addition to diagnostic, imaging, and therapeutic applications that are described in this article, optical fibers have been employed in a number of biomedical applications, for example, laser surgery and fiber‐based transducers for monitoring physiologically important parameters (temperature, pressure, oxygen saturation, blood flow). All those subjects have been covered in detail in the dedicated articles of this encyclopedia.
The structure of this article is the following. The first section provides general physical and engineering principles of fiber optics needed to understand the rest of the article. It discusses the physics of total internal reflection and throughput, fiber propagation modes, optical fiber construction, and types of fibers. The next section provides the reader with the review of illumination applications of fibers in medicine. The third section discusses the diagnostic applications of the biomedical fibers, including imaging and spectroscopy. The last section reviews therapeutic applications of fibers.
Cardiac Output, Fick Technique for
Authors: Faddy Steven C. 
Published: April 2006

Abstract
Cardiac output (CO) is an important measurement in many medical investigations. It is the amount of blood pumped by the ventricles of the heart and can be defined as the product of stroke volume (SV) and heart rate (HR), where stroke volume is the amount of blood expelled by the ventricle with each contraction and the HR is the number of contractions per minute.
Cardiac output gives an indication of ventricular function and is also used in the calculation of a number of flow‐dependent parameters, such as cardiac index, systemic vascular resistance, pulmonary vascular resistance, valve areas, and intracardiac shunt ratios.
The Fick technique is the gold standard in CO measurement. It relies on direct measurement of oxygen consumption and expenditure to derive the rate of blood flow throughout the individual.
Flowmeters, Electromagnetic
Authors: Fontaine Arnold A. , Deutsch Steven , Manning Keefe B. 
Published: April 2006

AbstractFluid flow occurs throughout biomedical engineering ranging from air flow in the lungs to diffusion of nutrients through membranes and involvesin vivoandin vitromeasurements. Flows involve fluid media in the form of gas, liquid, or multiphase flows of both liquids and gas together or in combination with solid matter. They can involve relatively benign flows like that of saline through an intravenous tube to a biochemically active flow of a nonNewtonian fluid such as blood. Many biomedical or bioengineering processes require the quantification of some flow field that may be directly or indirectly related to the process. Such quantification can involve the measurement of volume or mass flow, the static and dynamic pressures, the local velocity of the fluid, the motion (speed and direction) of particles such as cells, the flow‐related shear, or the diffusion of a chemical species.
Fluorescence Measurements
Authors: Klebe Robert J. , Zardeneta Gustavo , Horowitz Paul M. 
Published: April 2006

Abstract
Fluorescence measurements can be used to detect a large number of compounds with a sensitivity rivaling that of radioisotopic methods. In addition to sensitivity, fluorescence analysis provides a means to identify compounds, and determine the concentration of a given compound in a complex mixture. Such analyses can be carried out under nondestructive conditions. This article presents an overview of the theoretical basis of fluorescence spectroscopy as well as a discussion of technical considerations involved in several practical applications of this analytical method.
Heart Valve Prostheses
Authors: Chandran K. B. 
Published: April 2006

AbstractHeart valve prostheses have been successfully implanted in humans with diseased native heart valves for >40 years. Patients with implanted prostheses lead a relatively normal life. The currently available prostheses can be broadly classified into mechanical and biological heart valve prostheses. Mechanical valve prostheses are made entirely out of blood compatible nonbiological material, and hence are highly durable. However, thrombo‐embolic complications are still the major problem with these valves, and hence the patient has to be under long‐term anticoagulant therapy. Biological valves with leaflets made of biological tissue generally do not require long‐term anticoagulant therapy. However, they lack in durability with replacements becoming necessary at 10–12 years after implantation on the average. It is clear that further improvements are needed in the valve designs in order to improve the quality of life for patients implanted with valve prostheses. This article discusses the history of development of valve prostheses, mechanical and bioprosthetic valves currently available for implantation, and efforts in our understanding of the relationship between the dynamics of valve function and the problems existing with the current valve prostheses.
Hyperbaric Oxygenation
Authors: Whelan Harry T. , Niezgoda Jeffrey A. , Lewis Matthew C. , Kindwall Eric P. , Cabigas Bernadette 
Published: April 2006

AbstractHyperbaric oxygen (HBO) is simply the delivery of molecular oxygen in very high dosage. Even though experience has shown HBO to be very useful in a number of conditions, the exact mechanism of action at the molecular level is not fully understood. This article reviews the various studies and results of HBO since its inception.
Hyperthermia, Ultrasonic
Authors: Patel Dimpi , Lakkireddy Dhanunjaya , Natale Andrea 
Published: April 2006

AbstractThis article compares and contrasts electromagnetic waves to ultrasonic waves as a heating modality, explains the physics behind ultrasound generation, and explores the thermal and mechanical biophysics involved with ultrasound delivery to tissue. Then, the medical fields that are currently benefitting from conventional ultrasound hyperthermia and HIFU are considered, and finally some of the many applicators involved with thermal ultrasound delivery are evaluated.
Impedance Plethysmography
Authors: Hutten Helmut 
Published: April 2006

AbstractThe term impedance plethysmography is commonly used in medicine to denote the estimation of a volume by measuring certain passive electrical properties of biological tissues. Since the first research work about these electrical properties about one century ago, both the technologies and the methodologies have expanded in a large number of different directions. Most of the diagnostic applications in medicine are patient‐near with the device directly connected to the patient. However, the number of applications in the field of laboratory medicine is steadily increasing. Although not all described bioimpedance‐based plethysmographic methodologies have actually found broad application in clinical routine, there is still the challenge to improve and to further evaluate technologies and methodologies, and to identify new fields of application.
Incubators, Infant
Authors: White Robert 
Published: April 2006

Abstract
Infant incubators were first developed to keep ill or preterm infants warm. Because the human infant is more complex than, say a chicken egg, and because much more intervention occurs with an ill infant than with the egg, incubators have become very sophisticated devices. In addition, the incubator is now often used as a delivery device for oxygen and humidity, as the platform for a number of other devices to support the ill newborn, and as a mechanism to control sensory stimuli to the developing brain. As these functional demands have increased, so has the mechanical complexity of the infant incubator. This article reviews the historical and scientific foundations of incubator design, and then describe some of the mechanical strategies used to respond to these functional demands of the present generation of infant incubators.
Intrauterine Surgical Techniques
Authors: Bruner Joseph P. , Wilson R. Douglas , Adzick N. Scott , Wilkins‐Haug Louise , Marshall Audrey C. , Quintero Ruben A. , Yamamoto M. , Ville Y. , Johnson Anthony , Moldenhauer Julie S. 
Published: April 2006

Abstract
Intrauterine surgery of the fetus or fetal adnexae is spreading rapidly throughout the world. In a broad sense, intrauterine surgery includes any procedure in which a medical device is purposely placed within the uterine cavity. For most physicians, however, the concept of intrauterine surgery excludes such commonly performed procedures as amniocentesis and chorionic villous sampling. Rather, the term usually refers to techniques requiring specialized knowledge, experience, and most especially, instrumentation. Procedures most commonly mentioned in discourses on intrauterine surgery include those specifically developed for the treatment of such serious anatomic defects as congenital cystic adenomatoid malformation (CCAM), sacrococcygeal teratoma (SCT), lower urinary tract obstruction (LUTO), myelomeningocele, aortic or pulmonic stenosis, gastroschisis, iatrogenic amniorhexis, twin‐to‐twin transfusion syndrome (TTTS), and twins discordant for severe anomalies. As no one person in the world is an expert in every one of these procedures, the remainder of this chapter is divided into individual sections, each authored by someone widely recognized as a leader in the treatment of that particular anomaly.
Joints, Biomechanics of
Authors: Papaioannou George , Yeni Yener N. 
Published: April 2006

AbstractBones in the skeleton join to form segments or links that provide for the attachment of muscles, ligaments, tendons, and so on. Altogether, these systems of bones and soft tissues, called joints, produce movement for the organism. Joint biomechanics traditionally is a division of biomechanics that studies the effect of forces on the joints of living organisms. Like all other organs, joints are subject to trauma and disease. Development of treatments, devices and exercise regimes for healthy joints, as well as learning from the great variety of naturally existing joints for the purpose of nature‐inspired technology, requires a fundamental understanding of the mechanics of joints and joint tissues, and their interaction with the underlying biological mechanisms. At the current state of the art, the definition of joint biomechanics can be broadened to encompass these complex interactions and the relevant technology. It is the purpose of this article to introduce a current understanding of joint biomechanics with an emphasis on the structure, kinematics, kinetics, modeling and joint stability of human joints. A detailed consideration of the mechanics of artifical joints and that of the tissues forming a joint is left for other articles.
Laryngeal Prosthetic Devices
Authors: Belforte Guido , Carello Massimiliana , Bongioannini Guido , Magnano Mauro 
Published: April 2006

Abstract
Larynx is a complicated organ strategically located at the division of the upper aerodigestive tract into the gastrointestinal tract and the airway. Alteration of its function can have a significant impact on vocal, digestive and respiratory physiology. Laryngeal cancer changes the anatomy and the patient is deprived on the vibrating source and he cannot speak. Different methods to recover phonation after total laryngectomies have been developed to produce a new voice from the 1860 to today, electrical or pneumatic types. Actually the most used technique are: the oesophageal speech, the electrolarynx and the phonatory prosthesis.
Lenses, Intraocular
Authors: Hamam Habib 
Published: April 2006

Abstract
The IOLs are microlenses placed inside the human eye to correct cataracts, nearsightedness, farsightedness, astigmatism, or presbyopia. There are two types of IOLs: anterior chamber lenses, which are placed in the anterior chamber of the eye between the iris and the cornea, and posterior chamber IOLs, which are placed in the posterior chamber behind the iris and rest against the capsular bag.
Linear Variable Differential Transformers
Authors: Kesavan Sunil , Reddy Narender 
Published: April 2006

AbstractLinear variable differential transformers (LVDTs) are electromechanical transducers that generate an electrical output that is proportional to the displacement of their movable cores. The LVDTs offer excellent resolution and have static and dynamic characteristics that are highly suited for medical applications. This article presents the theory, fabrication, advantages, and disadvantages of these versatile transducers. In addition, the excitation, amplification and demodulation instrumentation that are used with LVDTs are discussed. The sections on selection criteria and medical applications of LVDTs could help readers develop applications for these versatile and cost‐effective transducers.