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PubMed1994

Data compression for medical report archiving.

In a hospital environment, where large numbers of reports are compiled, data compression offers a method for substantially reducing the required disk space whilst protecting the confidentiality of patient data. An analysis is given of the most important parameters that influence compression of free-text data, to realize an efficient implementation of an archiving system for medical reports. An overall reduction of the required disk space by more than 50% can be attained, as well as supplementary level of protection. A slight increase in access time is thereby inevitable, but almost insignificant. Such an archiving system constitutes a necessary component for an intelligent information retrieval system. The access to information contained in medical documents (by means of natural language processing and artificial intelligence techniques) is considered to be one of the key issues in the field of medical informatics for the coming decades.

Archives↗
PubMed1995

An interactive histology image-barcode manual for a videodisc image library.

UNLABELLED: Cell Biology and HISTOLOGY (alias Microanatomy, alias Microscopic Anatomy) is a required course for first-year medical and dental students in most health science centers. The traditional approach used in teaching this discipline is to present photomicrographic images of structures to students in lecture using 35 mm slides of fields seen through the microscope. The students then spend many hours viewing and studying specimens of tissues using a light microscope in a laboratory setting. Students in traditional courses of histology spend an inordinate amount of time learning the component structures by attempting to find and identify them in tissue sections using a microscope, where the structure being sought is surrounded by a multitude of other structures with which they are also not familiar. With the recent availability of videodisc stored image libraries of histological samples, it is now possible to study histological principles without the use of the microscope as the primary learning tool. A videodisc entitled " HISTOLOGY: A Photographic Atlas" by S. Downing (published by Image Premastering Services Limited, Minneapolis, MN, 1991) has been incorporated into our histology course. Fifteen videodisc player stations are provided for 150 students. Images are retrieved by students using a bar code scanner attached to a videodisc player (Pioneer CLD-2400). Using this kind of image library, students can now learn basic histological structure, such as cell and tissue types, without the use of a microscope or as a tool for facilitating microscopy. The use of a videodisc library of randomly accessible images simplifies learning the basic components which all organs are composed of by presenting the learner with clear-cut examples to avoid confusion with other structures. However, videodisc players and TV monitors are still not appropriately priced for every student to own. This presents a problem in that the same images studied in class are not available to study and review outside of class. There is a need for resources for additional study outside of the institutional setting, for students to have and interact with to reinforce the learning experience in the teaching laboratory. A hard copy manual was created and is being used in our course; it incorporates photos captured from the videodisc. The images displayed in the manual are chosen to give the student one example of each histological component. Additional labeling is added to the images, and each image is accompanied by a bar code that may be used at a videodisc player with a bar code reader to retrieve the same color image from the disc displayed in larger format on a TV monitor. Each topic in the manual is accompanied by learning objectives and a statement of clinical relevance. Following the presentation of the images in each section of the manual, the students are encouraged to practice by viewing multiple examples of each structural component presented in the lesson. They can do this by using the bar-coded catalog supplied with each disc. The presentation of each topic concludes with a quiz composed of questions about images that the student can retrieve from the videodisc using barcodes in the text of the manual. Some of the images on the quiz are printed in miniature in the manual to provide the student with an opportunity for personal review at home when hardware to obtain and display images from a video disc is not available. This manual provides an answer to the dilemma faced by the learner when access to hardware is not available; reinforcement is therefore facilitated outside the teaching laboratory. This allows learning to continue outside of the classroom, using the same materials. (abstract truncated)

Computer-Assisted Instruction↗
PubMed1999

Belt worn control system and battery for the percutaneous model of the Jarvik 2000 heart.

A belt worn controller and lithium-ion battery pack have been developed for use with the initial clinical trials of the Jarvik 2000 heart. Patient interface considerations, safety, and simplicity were major design inputs for the system. The controller was developed using all analog technology to avoid difficulties with electromagnetic interference (EMI), to minimize susceptibility to electrostatic discharge, and to avoid the need for software validation. Manual control of pump speed is accomplished by a patient operated knob, according to physician instructions for rest and exercise for each individual patient. The system includes alarms and indicators which show the following: the amount of remaining battery charge, if the battery is low and needs replacement, the power in watts being consumed, if the power consumed is above 15 W, if the pump is running below the selected speed setting, and if the pump stops. The control box, curved to be worn on the belt, is only 2.5 inches high for comfort when sitting. The battery pack, also form fitted for patient comfort, weighs just over 1 1/2 pounds and supplies 65 W-h of energy storage, sufficient to run the device for over 8 h at nominal load.

Computers, Analog↗
PubMed2001

Digital imaging modalities for dental practice.

The introduction of the computed tomograph in the 1970s revolutionized medical diagnosis by initiating the transition from analogue to digital imaging. During this period, more specialized equipment for image processing was developed, such as cathode-ray tubes for image display, special sensors for image acquisition, and storage devices for image archiving. Digital imaging systems designed exclusively for use in dentistry were developed in the latter half of the 1980s. Some are now being clinically applied under conditions of close scrutiny to determine diagnostic accuracy, image quality, and radiation exposure to patients. This article reviews the enabling technologies of digital systems used in dentistry, and focuses upon intraoral digital imaging systems, concepts for digital image acquisition, and variations in radiation dose and their effects on diagnostic accuracy of caries detection.

Data Display↗
PubMed2005

On the building of binary spelling interfaces for augmentative communication.

A criterion for design of optimal binary spelling interfaces (SI)--the average expectation of number of writing steps (trials) required to write one letter--is presented and discussed. This criterion is relevant for practical usage of any menu-oriented alternative communication system, mechanical device or brain-computer-interface, when a user (typically, a patient with devastating neuromuscular handicap) can not create an intended single binary response with an absolute reliability. An algorithm for building of a corresponding binary tree is developed and evaluated. This algorithm is efficient, when selection probabilities have essentially different values (the worst case).

Algorithms↗
PubMed1998

What's new in mammography.

Early diagnosis of breast cancer plays the leading role in reducing mortality rates and improving the patients' prognosis: mammography is the most sensitive technique currently available for the detection of nonpalpable lesions and therefore the method of choice. However, mammography has some limitations and the technique must be improved with technological devices without affecting image quality. This could be the target to increase diagnostic accuracy. Mammography sensitivity and specificity are now improved with the digital computer assisted technique, teleradiology, digital tomosynthesis or digital angiography--used to study microvascularization--3D imaging or synchrotron light, and laser mammography. Such other technological devices as Mammospot reduce breast thickness and provide better breast compression. Digital mammography can be carried out with film or direct digitization. The advantages of the digital technique are a shorter examination time, less storage space, electronic image recording, with image 'adjustments' made by the radiologist, and especially computerized analysis. The computer aided diagnosis can be defined as the diagnosis made by the radiologist who considers the results of computerized analysis as a 'second opinion'. In this way incidental mistakes made by radiologists, can be corrected by the computer analysis. Computers are a basic element also in teleradiology, which needs immediate and simultaneous admittance to the patient's history and permits radiology optimization in rural areas too. As for tomosynthesis, it permits to study a single slice of the breast without glandular tissue overlapping, which is useful in dense breasts where the diagnosis can be made with a lower X-ray dose. Moreover, this method fits the current mammographic systems easily. 3D imaging is still a work in progress. Synchrotron mammography is used only on surgery specimens, where it exhibits high resolution and contrast, depicting structures and details missed by conventional mammography. Breast DSA allows the study of vessels < 0.20 mm in diameter and of fine microvascular details; it can also demonstrate neoangiogenesis. Laser mammography permits bilateral examinations of the breast in 10-15 mins and is currently used also for breast cancer therapy, although only in animal trials. To conclude, after reviewing new techniques and evaluating the real cost/benefit ratio for each of them, conventional mammography remains the most sensitive tool for breast cancer diagnosis.

Angiography, Digital Subtraction↗
PubMed1997

Metabolic action of neuropeptide Y in relation to its effect on feeding.

Because energy homeostasis depends on a continuous balance between food intake, energy expenditure, and energy storage, it was expected that neuropeptide Y (NPY) could act not only on food intake but also on metabolic parameters. Using an original calorimetric device that allows the computation of the background metabolism (energy expenditure free from the cost of locomotor activity), we assessed the effect of a microinjection of NPY upon the quantitative (background metabolism, thermic effect of food) and qualitative (respiratory quotient) components of energy metabolism. NPY was injected into the juxtafornical hypothalamus at a dose that promotes feeding behavior (1 microg/0.5 microL) and enhances locomotor activity. Although total metabolism was increased proportionally to locomotion, no effect of NPY on background metabolism was observed when no food was available. Only following a calibrated meal given 30 min after the microinjection did NPY induce a delayed decrease in respiratory quotient whereas the postprandial background metabolism remained unaffected. In conclusion, only the new-generation calorimeters can show that the NPY-induced rise in overall metabolic rate is entirely accounted for by the unavoidable enhancement in locomotor activity and that the only metabolic effect of NPY is the delayed postprandial respiratory quotient decrease, suggesting a postabsorptive orientation toward more lipid utilization.

Animals↗
PubMed1982

Data acquisition and control system for multiparameter cell sorting based on DEC LSI-11 microprocessor.

A computer system has been developed to add data acquisition, display, storage, and processing capability to a multiparamenter flow cytometer/sorter. The system can handle one or two parameters in histogram mode. Alternatively one, two or more parameters are stored event-by-event on an external storage device in list-mode with a resolution of 12 bit. The processor can also control cell sorting. Usual multichannel analyzer features are implemented in software, using standard interface boards without special electronics. Data are accepted via Direct Memory Access (DMA), which depends only on hardware. Data acquisition deadtime is nearly independent of software routines such as graphics display and interactive work. Since more than 8000 events/sec are achieved for eight paramenter handling, the computer system has capacity for rapid data acquisition. Although there is no need for such high data acquisition rates in present flow cytometry, it gives the advantage of short single event acquisition and longer process control handling.

Cell Separation↗
PubMed1986

CD-ROM. A new advance in medical information retrieval.

The massive production of medical information is being met by new technologies for storing and retrieving knowledge. Recent years have witnessed the maturation of time-sharing information utilities into a full-blown industry. In medicine these services have provided bibliographic information but have recently expanded to full-text availability of journals and books. Now optical storage technology, most conspicuously the compact disk read only memory (CD-ROM), provides similar massive information storage and retrieval affordable to microcomputer users. Such devices might replace many of the functions of time-sharing.

Computers↗
PubMed1984

Two-dimensional, computer-controlled film scanner: quantitation of fluorescence from ethidium bromide-stained DNA gels.

A two-dimensional scanner based on a digital plotter is described. The device is used to analyze photographic negatives of ethidium bromide-stained DNA-agarose gels. Scanning is controlled by and photometric data transferred to a computer for processing, storage, display, and analysis such as integration of the areas under bands and determination of the mean distances of migration of polydisperse samples. An integral light source and detector module designed for reading optical "bar-codes" is mounted in place of the pen of the plotter. Spatial resolution and reproducibility are about 0.2 and 0.005 mm, respectively. Photometric precision as good as one part per thousand is achieved by sinusoidal modulation of the intensity of the light source and synchronous, phase-sensitive detection of the signal from the detector by a lock-in amplifier. No part of the sensor assembly touches the surface of the negative. In contrast to a densitometer, the computer transforms photometric data to values directly proportional to the amount of DNA at given points on the original gel. The ability to move the sensor in two dimensions over the negative allows for the integration across the width of a lane correctly allowing for the nonuniform distribution of the DNA.

Computers↗
PubMed1997

Simulation of radiation effects on three-dimensional computer optical memories.

A model was developed to simulate the effects of heavy charged-particle (HCP) radiation on the information stored in three-dimensional computer optical memories. The model is based on (i) the HCP track radial dose distribution, (ii) the spatial and temporal distribution of temperature in the track, (iii) the matrix-specific radiation-induced changes that will affect the response, and (iv) the kinetics of transition of photochromic molecules from the colored to the colorless isomeric form (bit flip). It is shown that information stored in a volume of several nanometers radius around the particle's track axis may be lost. The magnitude of the effect is dependent on the particle's track structure.

Biophysical Phenomena↗
PubMed2004

Text generation from Taiwanese Sign Language using a PST-based language model for augmentative communication.

This paper proposes a novel approach to the generation of Chinese sentences from ill-formed Taiwanese Sign Language (TSL) for people with hearing impairments. First, a sign icon-based virtual keyboard is constructed to provide a visualized interface to retrieve sign icons from a sign database. A proposed language model (LM), based on a predictive sentence template (PST) tree, integrates a statistical variable n-gram LM and linguistic constraints to deal with the translation problem from ill-formed sign sequences to grammatical written sentences. The PST tree trained by a corpus collected from the deaf schools was used to model the correspondence between signed and written Chinese. In addition, a set of phrase formation rules, based on trigger pair category, was derived for sentence pattern expansion. These approaches improved the efficiency of text generation and the accuracy of word prediction and, therefore, improved the input rate. For the assessment of practical communication aids, a reading-comprehension training program with ten profoundly deaf students was undertaken in a deaf school in Tainan, Taiwan. Evaluation results show that the literacy aptitude test and subjective satisfactory level are significantly improved.

Adolescent↗
PubMed2004

Error-tolerant sign retrieval using visual features and maximum a posteriori estimation.

This paper proposes an efficient error-tolerant approach to retrieving sign words from a Taiwanese Sign Language (TSL) database. This database is tagged with visual gesture features and organized as a multilist code tree. These features are defined in terms of the visual characteristics of sign gestures by which they are indexed for sign retrieval and displayed using an anthropomorphic interface. The maximum a posteriori estimation is exploited to retrieve the most likely sign word given the input feature sequence. An error-tolerant mechanism based on mutual information criterion is proposed to retrieve a sign word of interest efficiently and robustly. A user-friendly anthropomorphic interface is also developed to assist learning TSL. Several experiments were performed in an educational environment to investigate the system's retrieval accuracy. Our proposed approach outperformed a dynamic programming algorithm in its task and shows tolerance to user input errors.

Algorithms↗
PubMed2002

Microfluidic large-scale integration.

We developed high-density microfluidic chips that contain plumbing networks with thousands of micromechanical valves and hundreds of individually addressable chambers. These fluidic devices are analogous to electronic integrated circuits fabricated using large-scale integration. A key component of these networks is the fluidic multiplexor, which is a combinatorial array of binary valve patterns that exponentially increases the processing power of a network by allowing complex fluid manipulations with a minimal number of inputs. We used these integrated microfluidic networks to construct the microfluidic analog of a comparator array and a microfluidic memory storage device whose behavior resembles random-access memory.

Biochemistry↗
PubMed1992

The management of medical records.

An optical disk filing system is an efficient approach to storing medical records; however, this system has not yet been put to practical use because it is usually a "stand-alone" type indirectly connected to a hospital information system. We have developed a medical record management system with an optical disk filing system connected to the host computer in the hospital information system. We can retrieve and display the medical records through the CRT (Cathode Ray Tube) terminals of the hospital information system at every ward and outpatient clinic. The patient's clinical information can be sent to several areas in the hospital using the hospital information system.

Computer Communication Networks↗