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At least 469 records · Page 26Linked to original sources

PubMed2005

askMEDLINE: a free-text, natural language query tool for MEDLINE/PubMed.

BACKGROUND: Plain language search tools for MEDLINE/PubMed are few. We wanted to develop a search tool that would allow anyone using a free-text, natural language query and without knowing specialized vocabularies that an expert searcher might use, to find relevant citations in MEDLINE/PubMed. This tool would translate a question into an efficient search. RESULTS: The accuracy and relevance of retrieved citations were compared to references cited in BMJ POEMs and CATs (critically appraised topics) questions from the University of Michigan Department of Pediatrics. askMEDLINE correctly matched the cited references 75.8% in POEMs and 89.2 % in CATs questions on first pass. When articles that were deemed to be relevant to the clinical questions were included, the overall efficiency in retrieving journal articles was 96.8% (POEMs) and 96.3% (CATs.) CONCLUSION: askMEDLINE might be a useful search tool for clinicians, researchers, and other information seekers interested in finding current evidence in MEDLINE/PubMed. The text-only format could be convenient for users with wireless handheld devices and those with low-bandwidth connections in remote locations.

Academic Medical Centers↗

PubMed1994

[Computer-assisted measurement of ocular misalignment in infants and young children using the digital Purkinje reflection pattern procedure].

A digital image recording and processing system is presented that allows a quick diagnosis of microstrabismus in non-cooperative children. It is thus particularly suited for screening purposes. METHOD: The Purkinje Reflection Pattern Evaluation (RPE) method is used: three small flashes are used to produce the desired Purkinje images. Two horizontal rows of the three 1st Purkinje images (anterior corneal reflections) and of the three 4th Purkinje images (posterior crystalline lens reflections) stemming from the three light sources form the characteristic Purkinje image reflection pattern. Each eye's position is calculated from the shift between the upper and lower rows of reflections by means of two simple formulae. From the angles obtained in binocular fixation and monocular fixation the manifest angle of strabismus corresponding to the angle measured in the simultaneous prism-and-cover test is computed. The measurement is performed at a fixation distance of 50 cm under natural viewing conditions. To obtain a picture one only has to get the child's attention for a short moment. The primary position is triggered with the fixation light, which is operated by a switch. APPARATUS: The digital image recording is done with a hand-held device comprising two miniaturized video cameras, three photo flashes and a fixation light that is operated manually. An IBM-compatible PC equipped with a hard disk and two frame grabbers was adapted for the storage and processing of the pictures. The pictures are evaluated interactively in a few minutes on the workstation's monitor immediately after the measurement. To this end specially designed menu-driven software was implemented. RESULTS: Examples of the measuring procedure and clinical results in infants with microtropic highlight the potential of the system as a screening apparatus and for the exact measurement of small and large squint angles. Usually even 1-year-old children can cooperate well enough to get good-quality pictures in binocular fixation. The new digital system allows easy and rapid application of the Purkinje Reflection Pattern Evaluation method since the time-consuming photographic film processing and evaluation are no longer necessary. For the first time small angles of strabismus under 5 degrees (10 PD) can be measured with a precision of less than 1 degree (2 PD) under clinical conditions in non-cooperative children.

Adult↗

PubMed2000

Digital imaging for dental caries.

Laboratory studies show that digital intraoral radiography systems are as accurate as dental film for the detection of caries when a good-quality image is obtained, although more re-takes might be necessary because of positioning errors with the digital systems, particularly the charge-coupled device sensors. The phosphor plate is more comfortable for the patient than nondigital systems, and the dose can be further reduced with the storage phosphors. Cross-contamination does not pose a problem with digital systems if simple hygiene procedures are observed.

Cross Infection↗

PubMed1987

A simple electronic device and computer interface system for monitoring chewing behavior of stall-fed ruminant animals.

A simple and low cost electronic switching device interfaced to a microcomputer was developed and utilized to monitor the chewing behavior of stall-fed cattle. The system transforms jaw movements directly into binary notation. The device is attached to a halter and consists of two contact points inserted into a piece of rubber tubing. Elongation of the rubber tubing by the movements of the lower jaw breaks the electrical circuit between the contact points. Every break in the circuit is recorded as a chew by the time-clock-equipped microcomputer, which records animal and time of each chew (nearest second). Data are stored automatically at the end of every hour and later transferred to diskettes for permanent storage and future processing. Use of an interface card allows simultaneous monitoring of up to eight animals. A program was written to separate chewing during eating from chewing during rumination. The system has been used successfully for approximately 2500 steer-h and could be easily adapted to most species of ruminants.

Animals↗

PubMed1987

Electronic imaging system for direct and rapid quantitation of fluorescence from electrophoretic gels: application to ethidium bromide-stained DNA.

We have built an electronic imaging system based on a modified charge-coupled-device television camera that directly quantitates the distribution of fluorescence from electrophoretic gels, chromatograms, and other stationary sources. Exposure times can exceed 1 min. Unlike the photographic system that it replaces, the response of the camera is directly proportional to the intensity of incident fluorescence, and image data are digitized and stored in computer memory ready for analysis immediately upon completion of an exposure. We describe procedures for the display, normalization, and archival storage of image data and programs that use images of ethidium bromide-stained DNA in alkaline agarose gels to quantitate single-strand breaks in DNA.

DNA↗

PubMed1998

Electrogram signals recorded from acute and chronic pacemaker implantation sites in pacemaker patients.

Electrogram signals recorded from typical pacemaker implantation sites may be useful for a variety of pacemaker system functions including pacemaker follow-up, atrial and ventricular sensing (event detection), and triggered electrogram storage. We quantified the electrical characteristics of pacemaker pocket electrograms using a subcutaneous electrode array (SEA) in a population of 48 patients undergoing initial or replacement pacemaker implantation. SEA recorded intrinsic R wave amplitudes measured peak to peak averaged 118 microV and 65 microV for the two recorded SEA electrograms and were significantly different (P < 0.001); paced R wave amplitudes averaged 180 microV and 110 microV. P wave amplitudes averaged 39 microV and 26 microV. No statistically significant difference in amplitudes were observed between acute versus chronic pacemaker pocket or indication for pacing (AV block, sick sinus syndrome). Signal to noise ratios, using R wave amplitude as signal, were lower in the SEA electrogram on average (11 dB) compared to the intracardiac electrogram (27 dB), but sufficient for diagnostic assessment. R wave/P wave ratios for SEA signals were lower than surface and intracardiac values 3.1 and 2.7 compared to a range of 6.2-9.8, indicating a relative enhancement of P waves to R waves in SEA signals. In summary, SEA electrograms are of sufficient amplitude and signal quality (signal to noise ratio) to hold promise for future implantable device features such as electrogram telemetry, enhanced sensing, and diagnostic data storage.

Adult↗

PubMed1995

A double chamber system for producing constant radon concentration.

An experimental arrangement of a radon chamber with an intrinsic constancy of the relative radon concentration is described. The system consists of a reference chamber and an auxiliary storage chamber. The only active device is a timer-controlled pump or valve which feeds radon gas from the storage into the reference chamber. The switching pattern of the timer is extracted from model calculations and theoretically performs an exact compensation of the radon loss by radioactive decay. If the calculations are done in real time and online, every known external event influencing the radon concentration can be compensated. This paper presents a simple timer circuit and a computer code which generates the timer program. The influence of the air flow stability and the leakage of the chambers are discussed. It is planned to apply this theoretical approach to provide a constant radon gas concentration for an actual chamber.

Calibration↗

PubMed2005

Decoding of auditory cortex signals with a LAMSTAR neural network.

OBJECTIVES: Each neuron has a specific set of stimuli, which it preferentially responds to (the receptive field of the neuron). For implantable cortical prosthetic devices specific points of the cortex (or groups of neurons) have to be stimulated to create perceptions of sensory stimulus with specific attributes (such as frequency, temporal characteristics, etc). Such applications would need real time decoding of signals. Previously mathematical techniques, such as computing the receptive field (using electrophysiology data) and artificial neural networks (Kohonen network or SOM and back propagation network) have been used to decode neural signals. METHODS: A Large Adaptive Memory Storage and Retrieval (LAMSTAR) neural-network-based decoder was designed to decode responses recorded from neurons in the auditory cortex. It was designed to identify the frequency of the tonal stimuli that elicited a particular discharge rate pattern recorded on two channels of a tungsten wire electrode array. RESULTS: The network functioned efficiently as a decoder with 100% accuracy for the small sample of stimulus-response data used. DISCUSSION: The results show that the network is effective in studying the functional organization of the auditory cortex and other sensory systems. Depending on the input sub-word, information about the kind of stimuli that activates particular parts of the sensory cortex can be studied.

Acoustic Stimulation↗

PubMed1994

Evaluation of a dual bias dual metal oxide-silicon semiconductor field effect transistor detector as radiation dosimeter.

A new type of direct reading semiconductor dosimeter has been investigated as a radiation detector for photon and electron therapy beams of various energies. The operation of this device is based on the measurement of the threshold voltage shift in a custom-built metal oxide-silicon semiconductor field effect transistor (MOSFET). This voltage is a linear function of absorbed dose. The extent of the linearity region is dependent on the voltage controlled operation during irradiation. Operating two MOSFETS at two different biases simultaneously during irradiation will result in sensitivity (V/Gy) reproducibility better than +/- 3% over a range in dose of 100 Gy and at a dose per fraction greater than 20 x 10(-2) Gy. The modes of operation give this device many advantages, such as continuous monitoring during irradiation, immediate reading, and permanent storage of total dose after irradiation. The availability and ease of use of these MOSFET detectors make them very promising in clinical dosimetry.

Biophysical Phenomena↗

PubMed2005

Current products and practices: personal digital assistants in orthodontics.

Personal Digital Assistants (PDAs) have certain advantages over conventional diaries and are thought of as the 'electronic filofax'. They can be backed up, used for personal and professional organization, integrated with mobile phones for email and Internet access, image storage, logbook functions and audit. They are limited when used for desktop functions. This article attempts to highlight the current advantages and disadvantages of PDAs for use in orthodontics, and provides some guidance to those who are considering the purchase of such a device.

Cell Phone↗

PubMed2004

Security infrastructure services for electronic archives and electronic health records.

Communication and co-operation in the domain of healthcare and welfare require a well-defined set of security services based on a Public Key Infrastructure and provided by a Trusted Third Party (TTP). These services describe both status and relation of communicating principals, corresponding keys and attributes, and the access rights to applications and data. Additional services are needed to provide trustworthy information about dynamic issues of communication and co-operation such as time and location of processes, workflow relations, and system behaviour. Legal, social, behavioural and ethical requirements demand securely stored patient information and well-established access tools and tokens. Electronic (and more specifically digital) signatures--as important means for securing the integrity of a message or file--along with certified time stamps or time signatures are especially important for purposes of data storage in electronic archives and electronic health records (EHR). While just mentioning technical storage problems (e.g. lifetime of the storage devices, interoperability of retrieval and presentation software), this paper identifies mechanisms of securing data items, files, messages, sets of archived items or documents, electronic archive structures, and life-long electronic health records. Other workshop contributions will demonstrate related aspects of policies, patient privacy, and privilege management.

Access to Information↗

PubMed1998

SPring-8 beamline control system.

The SPring-8 beamline control system is now taking part in the control of the insertion device (ID), front end, beam transportation channel and all interlock systems of the beamline: it will supply a highly standardized environment of apparatus control for collaborative researchers. In particular, ID operation is very important in a third-generation synchrotron light source facility. It is also very important to consider the security system because the ID is part of the storage ring and is therefore governed by the synchrotron ring control system. The progress of computer networking systems and the technology of security control require the development of a highly flexible control system. An interlock system that is independent of the control system has increased the reliability. For the beamline control system the so-called standard model concept has been adopted. VME-bus (VME) is used as the front-end control system and a UNIX workstation as the operator console. CPU boards of the VME-bus are RISC processor-based board computers operated by a LynxOS-based HP-RT real-time operating system. The workstation and the VME are linked to each other by a network, and form the distributed system. The HP 9000/700 series with HP-UX and the HP 9000/743rt series with HP-RT are used. All the controllable apparatus may be operated from any workstation.

Journal Article↗

PubMed1980

A systematic approach to reconstructing microcircuitry by electron microscopy of serial sections.

To observe certain quantitative features of neuronal geometry and microcircuitry, it is necessary to reconstruct neurons from electron micrographs of serial, ultra-thin sections. We describe here an approach to preparing, photographing, and analyzing moderately long series (100-500 sections). A series is prepared using an assembly line approach: one operator cuts while a second mounts ribbons of sections using various mechanical aids. Photographs are taken in the electron microscope at low magnification and high accelerating voltage. Sequential negatives are aligned using an image combiner and copied, using quasi-coherent illumination, onto 35 mm film. The resulting "movie' is mounted on a precision film transport mounted on an X-Y stage controlled by stepping motors. The movie is viewed through a high resolution video system while a video storage device and switching system permit rapid alternation between frames for comparisons. The profiles of a process in successive frames are "microaligned' by small adjustments of the transport's X-Y position. The absolute X-Y biological coordinates for each frame and the correction necessary to bring it into alignment are stored in a Z80 microprocessor as a process vector. When the movie is re-examined with the stepping motors under control of the computer, the microaligned process shows almost no frame-to-frame jitter. The process vector may be used to generate a "branch schematic' of the neuron. The microaligned profiles can also be digitized and displayed as a reconstruction using a PDP 11/34 computer. Uses of the approach are presented with examples from the cat retina and visual cortex.

Animals↗

PubMed1985

Toxicology information systems: a historical perspective.

Toxicology information systems have evolved swiftly from early, library-based bibliographic tools to advanced packages utilizing sophisticated computer and telecommunication technologies. These systems have evolved concurrently with the rapid expansion of the science of toxicology itself. Bibliographic files such as TOXLINE represent first attempts to handle the toxicology literature through on-line retrieval. Subsequent approaches applied the use of computers to provide literature-derived data, as in TDB or RTECS, or to capture data directly in the laboratory. Societal concerns about hazardous substances, manifested in legislation and regulations, have been responsible for the creation of many computerized systems. Advanced, integrated information management systems are being explored as a method of accessing a large number of independently maintained toxicology databases. Changes in information technologies such as the trend toward microcomputers and novel high-density storage devices will affect the future of toxicology information systems as will impending developments in toxicology itself related to biotechnology, analytical methodology, and alternatives to whole animal testing.

History, 20th Century↗

PubMed2001

A connectivity standard for point-of-care testing.

A software standard has been designed that will facilitate the linking of all point-of-care testing (POCT) devices to information systems. This standard will replace the myriad of proprietary and incompatible solutions that currently exist. The standard is expected to be a feature of new POCT instruments by 2002.

Computer Communication Networks↗

PubMed1999

Taking advantage of sophisticated pacemaker diagnostics.

The ever-increasing complexity of pacing systems, combined with functions that vary from one manufacturer to another, can pose challenges during analysis of device function. Standard pacemaker diagnostics are measured data, electrogram telemetry, maker annotations and event counters, albeit with their current limitations. New diagnostic features discussed include time-based diagnostics, histograms of sensed amplitudes, pacing thresholds, or impedance trending. Mode-switching algorithms, combined with diagnostic features, facilitate the use of dual-chamber devices in patients with paroxysmal atrial tachyarrhythmias. The introduction of electrogram storage into pacemakers further improves diagnostic capabilities and allows a permanent validation and optimization of diagnostic and therapeutic algorithms. External diagnostic devices, which provide Holter recordings with continuous marker annotations and patient-triggered diagnostics, are additional features that will become increasingly important.

Arrhythmias, Cardiac↗

PubMed2003

[Initial experience with the EAS-1000 (NIDEK) anterior segment analyzer].

The analyzer of anterior segment EAS-1000 is one of recently developed diagnostic devices, used for digital photography for the analysis and storage of data about the anterior segment of the eye. The aim of the contribution is to inform the public about possible use of the apparatus in clinical and field practice.

Anterior Eye Segment↗

PubMed1996

An integrated approach to senology education: combination of a hypermedia program with a multimedia archive.

The aim of this work was to demonstrate the computerized system on senology, which combines a hypermedia application to a multimedia didactical archive, integrated with a radiological information system. These applications have been developed on Macintosh computers using the softwares Supercard and 4th Dimension. The hypermedia application deals with basic principles of anatomy as well as the radiologic semeiology and pathology through different imaging techniques in order to illustrate basic principles. Thus, students can modify their learning pathways and the timing as they wish. Limitations are related to time consumption in preparing the programs and technical difficulties in expanding them. Multimedia archive allows to classify a large number of difficult and uncommon clinical cases, creating an easily updatable teaching file in digital format which considerably improves access to stored image data, also reducing loss of films and film degradation. From initial experiences we conclude that these systems are valid devices in information and up to date for physicians dedicated to the study of breast pathology.

Breast↗