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[General anesthesia outside the operating room in patients with Pierre-Robin syndrome].

Anesthesiologists are increasingly asked to involve in administering general anesthesia outside the operating room for such procedures as computed tomography, magnetic resonance imaging or angiography. Especially, pediatric patients require some kind of sedation or general anesthesia during these procedures. We report general anesthesia outside the operating room in patients with Pierre-Robin syndrome, who are expected to have possible difficult airway. A one-year-old girl and a 16-year-old boy were anesthetized for cardiac catheterization. General anesthesia was given at the angiography room which was located outside the operating room. Anesthesia was induced with oxygen, nitrous oxide and sevoflurane while portable storage unit for difficult airway was prepared including various types and size of laryngoscopes, laryngeal mask airway, fiberoptic intubation equipment and surgical airway access. Fortunately, tracheas were successfully intubated without using special devices, although cautious care during induction was taken. According to development of medical and surgical procedures, it is readily presumed that anesthesiologists will be more often involved in the sedation or anesthesia conducted outside the operating room in future. Anesthesiologists should always ensure enough staffing, proper monitoring and equipment when sedation or anesthesia is conducted outside the operating room, particularly if patients have anesthetic risks.

Adolescent↗

[Automated and semiautomated perimetry. Comparative trial of 3 devices (Baylor programmer, Friedmann Mark II campimeter, Octopus 2000 R.)].

Modern perimetry involves automated or semi-automated procedures, this computer assisted perimetry (CAP) providing results independent of the examiner, and with marked discrimination of light sensibility through quantification of points tested. A wide variety of CAP devices are available, and a comparative study was conducted in 50 patients using 3 perimetric apparatuses with similar supraliminal static techniques but with variable automated potentials: The Goldman perimeter modified by "Baylor visual fields programmer": static technique for the middle area and kinetic for the peripheral area. The Friedmann Mark II Visual Fields Analyser with a multiple stimulus static technique for the middle area. The Fankhauser Octopus 2000 R perimeter with a precise static technique for middle and peripheral areas. This perimeter, highly automated, also allows statistical evaluation of defects changes, owing to storage of results on magnetic discs. Patients studied had either: glaucoma (25 cases) or neuro-ophthalmologic and retinal disorders (24 cases). Conclusions drawn from the experience acquired by the authors during more than one year of use of the 3 devices were: Rate of detection of defects is excellent with the Octopus and quite good with the Friedmann MKII, but limited in the middle area. The Baylor program does not allow quantification of defects. The image is clear with the Octopus as far as the gray scale is concerned, and more exact as far as the comparative tables are concerned; is not clear with the Friedmann MKII; is typical and clear with the Baylor. The length of examination (which varies with the programs used as far as the Octopus is concerned, and with the patient's reaction time) is usually long with the Octopus and the Friedmann, but short with the Baylor. Time and energy can be gained by the use of the Octopus, since it supplies data obtained from use of the Baylor program associated with that of the Friedmann MKII. The authors prefer to follow up campimetric evolution of glaucomatous patients with the Octopus because it offers more sensibility and precision in quantifying losses. The application of the statistical evaluation delta program on the 2000 R device, which will soon be tested in the Ophthalmological Department, could in an objective way indicate whether there is stabilization or a real progression of glaucomatous defects.

Adenoma↗

Investigation of saddle trajectories for cardiac CT imaging in cone-beam geometry.

This paper investigates cone-beam tomography for a wide class of x-ray source trajectories called saddles. In particular, a mathematical analysis of the number of intersections between a saddle and an arbitrary plane is given. This analysis demonstrates that axially truncated cone-beam projections acquired along a saddle can be used for exact reconstruction at any point in a large volume. The reconstruction can be achieved either using a new algorithm presented herein or using a formula recently introduced by Katsevich (2003 Int. J. Math. Math. Sci. 21 1305-21). The shape of the reconstructed volume and the properties of saddles make saddles attractive for cardiac imaging. Three examples of saddles are presented with a discussion of implementation on devices similar to modern C-arm systems and multislice CT scanners. Reconstruction with one of these saddles has been tested using computer-simulated data, with and without truncation. The imaged phantom for the truncated data is a FORBILD head phantom (representing the heart) that has been modified and embedded inside the FORBILD thorax phantom. The non-truncated data were generated by excluding the thorax. The reconstructed images demonstrate the accuracy of the mathematical results.

Algorithms↗

Beyond the peak flow meter: newer technologies for determining and documenting changes in lung function in the workplace.

There are many potential problems with the use of serial peak expiratory flow (PEF) measurement to investigate potential occupational asthma. Among these are inaccurate and incomplete recording of results. However, PEF meters will continue to be used because of their relatively low cost and the availability of improved graphing methods and computer-assisted interpretation (OASYS-2). New technologies that automatically record PEF values and the time at which the maneuver was performed have improved the reliability of serial PEF measurements. Further, new hand-held spirometers not only record the test time but also the FEV&inf1; and FEV&inf6;, in addition to PEF. Automated assessment of maneuver quality with immediate feedback to the worker may improve test quality. The storage of raw volume-time or flow-volume curves, not yet widely available, can be used by reviewers to evaluate the quality of the maneuver on which PEF and FEV&inf1; values are based-further improving the reliability of serial measurements. Mechanical stimulators and testing waveforms are available to thoroughly test these new devices and insure that they meet the minimum ATS requirements for monitoring devices.

Asthma↗

A distributed approach to integrated inquiry and display for radiology.

Picture archive and communications (PACS) systems should be flexible and modular in design so that new advances in storage, computation, and display technology can be introduced into the system without a significant redesign of existing software. The acquisition, storage, and management of radiologic images must be carefully integrated with a radiology information system. Our architecture is based on a four-level data model: (1) patient information, (2) examination information and reports, (3) image information, and (4) instances of images. The PACS being developed at the Mallinckrodt Institute of Radiology within the Electronic Radiology Laboratory consists of three primary components: application clients, database servers and image servers. One type of application client is an image-capable workstation that supports a radiology image viewing application. The application client queries the database server for information regarding patient and examination data in response to user-level requests. The database server responds to the request by retrieving the appropriate patient demographics and examination information, along with a pointer to the image/instance data from a central database. The client then uses the image data pointer to query the image server for the actual pixel data. The image server responds by transmitting the pixel data to the requesting application client or a designated auxiliary display device. Other clients act as image data acquisition nodes. Queries to the database servers are made via a library of callable subroutines. Software integrity is maintained throughout the system by dynamically loading software from a code-control database. Inquiry and display transactions, supported on a local-area network (Ethernet), have been measured and analyzed. Results and observations are presented.

Computer Communication Networks↗

Development and validation of an isotope-dilution electrospray ionization tandem mass spectrometry method with an on-line sample clean-up device for the quantitative analysis of the benzene exposure biomarker S-phenylmercapturic acid in human urine.

An isotope-dilution electrospray ionization tandem mass spectrometry (ESI-MS/MS) method with an on-line sample clean-up device, for the quantitative analysis of human urine for the benzene exposure biomarker S-phenylmercapturic acid (SPMA), was developed and validated. The sample clean-up system was constructed from an autosampler, a reversed-phase C18 trap cartridge, a two-position switching valve, and controlling computer software and hardware. The sample clean-up system was interfaced via 1/20 splitting to the ESI source of a triple-quadrupole mass spectrometer using negative ion mode and multiple reaction monitoring for SPMA and the isotope-labeled internal standard. A strategy was adopted to acquire pooled blank urine matrix and quality control samples spiked with standards. Validated procedures and data on method specificity, detection limits, standard curves, precision and recovery, sample storage stability, and inter-laboratory comparison are presented. The analytical system was fully automated. No tedious manual sample clean-up procedures are required. With the selectivity and the sensitivity provided by ESI-MS/MS detection, the analytical system can be used for high-throughput and accurate determination of SPMA levels in human urine samples, as a biomarker for environmental as well as occupational benzene exposure.

Acetylcysteine↗

Communication with a chaotic traveling wave tube microwave generator.

Traveling wave tubes (TWTs) are vacuum electronic amplifiers (see Beck, Gittins, and Pierce) that are commonly used for communication in the centimeter wavelength range. Increasing demand for high data flow in wireless communication systems (satellite communication systems are a good example) raises needs for making TWT's more compact and efficient. Motivated by this we suggest a scheme in which a TWT with feedback is operated in a highly nonlinear regime where the device behaves chaotically. The chaos is controlled using small controls. Then, at the receiving end a receiving TWT synchronizes to the chaotic transmitter and amplifies the received signal with nearly no distortion. Results on numerical simulations of the proposed scheme are reported and used to evaluate its effectiveness.

Communication↗

[The disposing techniques of evoked potentials].

This paper is to bring forward the new disposing techniques of evoked potentials which include four aspect techniques of the averaging, the recording, digital sampling and filters about the averaging, evoked potential amplitude, evoked potential latency, evoked potential recording, and evoked potential generations. The technique of the averaging including signal filtering and a periodic averaging, can enhance EP dedection. The commercial EP machines also plot changes in latency between serial EP studies in order to detect trends in peak latency. The modern digital EP recording device consists of sensory stimator, recording amplifiers with analog filters, an analog-to-digital converter, a digital signal averager, and a display and storage system. A sample-and-hold function is one of the recent developments which used EP collectors that provide simultaneous recording with multiple channels employing different time and voltage scales and sampling rates. The EP data may be further processed following A-D conversion by digital filters.

Electroretinography↗

Progress on the development of the MediWatch ambulatory blood pressure monitor and related devices.

The MediWatch is a wrist-mounted noninvasive blood pressure monitor designed to capture the radial pulse waveform using arterial tonometry and yield blood pressure measurements when the waveform is calibrated. An early prototype of this monitor uses a pulse-sensing system with a cylindrical plunger to applanate the radial artery. This prototype was evaluated against simulated blood pressure generated by a pneumatic pressure-pulse generator. The simulation-based results show that the prototype gave accurate pressure measurements when the MediWatch waveforms were calibrated against the simulator's pressure, indicating that the pulse-sensing system was able to measure force accurately. The prototype was clinically evaluated against intra-arterial pressure on post-open heart surgery patients. The results show that, under stationary conditions, for short periods of time and when the MediWatch waveforms were calibrated against the intra-arterial pressure, the prototype gave measurements that satisfy some of the statistical criteria of the 1993 Association for the Advancement of Medical Instrumentation standard, the 1993 British Hypertension Society protocol and the 2002 European Society of Hypertension protocol. These clinical results indicate that, under the stated test conditions, the prototype was able to accurately track changes in the patients' systolic and diastolic pressures. The MediWatch is being developed into an ambulatory device that provides a macroscopic view of the patient's blood pressure through measurement at preprogrammed intervals over 24 h, as well as a microscopic view of the patient's pressure through the pulse waveform captured during each measurement cycle. The design features of the MediWatch are being adapted for other applications that require the arterial pulse waveform, calibrated beat-to-beat blood pressure or both. An improved MediWatch prototype has been developed that provides memory storage for measurement data and functions as an integral part of a Web-based system that allows measurement data to be accessed over the Internet. A pulse-wave analyser has been developed that allows the radial pulse waveform to be captured, calibrated and viewed in real time on a personal computer. A continuous noninvasive blood pressure monitoring system based on arterial tonometry is being developed for use as an alternative to the arterial line in invasive blood pressure monitoring.

Aged↗

Comparison of measured and calculated dose rates for the Castor HAW 20/28 CG.

In January 2003 neutron and gamma dose rate measurements at a CASTOR HAW 20/28 CG were performed by the Bundesamt für Strahlenschutz at Gorleben. First, commercial dose rate measurement devices were used, then spectral measurements with a Bonner sphere system were made to verify the results. Axial and circumferential dose rate profiles were measured near the cask surface and spectral measurements were performed for some locations. A shielding analysis of the cask was performed with the MCNP Monte Carlo Code with ENDF/B-VI cross section libraries. The cask was modelled 'as built', i.e. with its real inventory, dimensions and material densities and with the same configuration and position as in the storage facility. The average C/E-ratios are 1.3 for neutron dose rates and 1.4 for gamma dose rates. Both the measured and calculated dose rates show the same qualitative trends in the axial and circumferential direction. The spectral measurements show a variation in the spectra across the cask surface. This correlates with the variation found in the C/E-ratios. At cask midheight good agreement between the Bonner sphere system and the commercial device (LB 6411) is found with a 7% lower derived H*(10) dose rate from the Bonner sphere system.

Computer-Aided Design↗

Virtual rehabilitation--benefits and challenges.

OBJECTIVES: To discuss the advantages and disadvantages of rehabilitation applications of virtual reality. METHODS: VR can be used as an enhancement to conventional therapy for patients with conditions ranging from musculoskeletal problems, to stroke-induced paralysis, to cognitive deficits. This approach is called "VR-augmented rehabilitation." Alternately, VR can replace conventional interventions altogether, in which case the rehabilitation is "VR-based." If the intervention is done at a distance, then it is called "telerehabilitation." Simulation exercises for post-stroke patients have been developed using a "teacher object" approach or a video game approach. Simulations for musculo-skeletal patients use virtual replicas of rehabilitation devices (such as rubber ball, power putty, peg board). Phobia-inducing virtual environments are prescribed for patients with cognitive deficits. RESULTS: VR-augmented rehabilitation has been shown effective for stroke patients in the chronic phase of the disease. VR-based rehabilitation has been improving patients with fear of flying, Vietnam syndrome, fear of heights, and chronic stroke patients. Telerehabilitation interventions using VR have improved musculo-skeletal and post-stroke patients, however less data is available at this time. CONCLUSIONS: Virtual reality presents significant advantages when applied to rehabilitation of patients with varied conditions. These advantages include patient motivation, adaptability and variability based on patient baseline, transparent data storage, online remote data access, economy of scale, reduced medical costs. Challenges in VR use for rehabilitation relate to lack of computer skills on the part of therapists, lack of support infrastructure, expensive equipment (initially), inadequate communication infrastructure (for telerehabilitation in rural areas), and patient safety concerns.

Cognition Disorders↗

Image identification system based on an optical broadcast neural network processor.

We describe the implementation of a vision system based on a hardware neural processor. The architecture of the neural network processor has been designed to exploit the computational characteristics of electronics and the communication characteristics of optics in an optimal manner, thus it is based on an optical broadcast of input signals to a dense array of processing elements. The vision system has been built by use of a prototype implementation of a neural network processor with discrete optic and optoelectronic devices. It has been adapted to work as a Hamming classifier of the images taken with a 128 x 128 complementary metal-oxide semiconductor image sensor. Its results, performance characteristics of the image classification system, and an analysis of its scalability in size and speed, with the improvement of the optoelectronic neural processor, are presented.

Algorithms↗

Medical expert systems: design and applications in pulmonary medicine.

Expert systems are computer applications with a built-in knowledge of a special field to solve problems like a human expert on this subject. An expert system consists of an inference component for problem specification and solving, a knowledge base for storage of data, facts, rules and heuristics, an interface for knowledge acquisition, another for the interaction with the user, and a component for reasoning. Pulmonary expert systems are used for automatic interpretations of lung function data which are measured on-line and directly computed. There are also some expert systems for consultation in difficult pulmonary cases and for protection against overlooking rare diseases. Perhaps the most successful applications of pulmonary expert systems are for educational purposes and a large variety of teachware is available. Pulmonary expert systems are presently limited to small applications; often it is necessary to type in large amounts of data and to follow a deeply structured cumbersome dialog. Also, the problem of responsibility for computer decisions has to be mentioned. But pulmonary expert systems as integrated supplements of normal pulmonary measuring devices, as decision support, and as parts of pulmonary teachware will be helpful tools for the pneumological physician.

Artificial Intelligence↗

Mobile access to biological databases on the Internet.

We have developed a new way of accessing biological databases and bioinformatics applications on the Internet. This new service, bioinformatics wireless application protocol (BioWAP) service, which is accessible by mobile devices makes it possible to access bioinformatics services, where normal PC or personal digital assistant (PDA) connections are not feasible. The BioWAP service includes major biological databases and applications demonstrating a simple method of implementing WAP interfaces to uncompliant applications, i.e. the applications that are not WAP or Internet based. The BioWAP service can be browsed with any WAP terminal.

Computational Biology↗

Magnetic nanostructures and materials in magnetic random access memory.

The advances in magnetic random access memory provide a remarkable showcase for the rapid development and application of nanodevices. Several aspects of state-of-the-art magnetic nanoscience and nanotechnology are developed and utilized in this single device. Current magnetic random access memory design is built upon the discovery and understanding of physics issues such as giant magnetoresistance, spin-dependent tunneling, exchange bias, and magnetic anisotropy in small elements. Successful magnetic random access memory development requires future research in some of the key areas involving nanotechnology. For example, the uniformity of the barrier thickness across the entire device and magnetic switching stability of a nanosized element are challenging issues that lie ahead. The spin degree of freedom of electrons is an added dimension that is both unique and useful in electronic transport and information technology. Nonvolatile, high-density, high-speed, and low-power magnetic random access memory is one of the first examples of the application of spintronics.

Computer Systems↗

Laser-induced ultrafast spin reorientation in the antiferromagnet TmFeO3.

All magnetically ordered materials can be divided into two primary classes: ferromagnets and antiferromagnets. Since ancient times, ferromagnetic materials have found vast application areas, from the compass to computer storage and more recently to magnetic random access memory and spintronics. In contrast, antiferromagnetic (AFM) materials, though representing the overwhelming majority of magnetically ordered materials, for a long time were of academic interest only. The fundamental difference between the two types of magnetic materials manifests itself in their reaction to an external magnetic field-in an antiferromagnet, the exchange interaction leads to zero net magnetization. The related absence of a net angular momentum should result in orders of magnitude faster AFM spin dynamics. Here we show that, using a short laser pulse, the spins of the antiferromagnet TmFeO3 can indeed be manipulated on a timescale of a few picoseconds, in contrast to the hundreds of picoseconds in a ferromagnet. Because the ultrafast dynamics of spins in antiferromagnets is a key issue for exchange-biased devices, this finding can expand the now limited set of applications for AFM materials.

Journal Article↗

[Technical and methodologic aspects of ambulatory long-term blood pressure monitoring systems].

The development of noninvasive, portable blood pressure measuring units began in 1962 with semi-automatic devices and cassette recorders, followed by the first automatic unit in 1968 and the introduction of digital storage system in 1978. Systems in common use today consist of a portable, battery-driven blood pressure monitor and a print-out unit. In the following, the System 5200 from SpaceLabs, which has been in use for three years in our clinic, will be described. TECHNICAL ASPECTS: In a monitor unit, amplication and filtering of analogue data measured and differentiation between signal and noise is carried out. An A/D converter digitalizes the analogue data. An integrated microprocessor analyses measured data, regulates inflation and deflation of the cuff pressure, out-put of measured and calculated values on an LCD display and storage of data. Data from 200 measurements is stored in a 2K byte RAM CMOS system. A personal computer serves for programming the monitor and evaluation of the stored data. Blood pressure measurement is carried out auscultatory with a microphone or oscillometrically if Korotkoff sounds are not detected. If the signal is disturbed, measurement is repeated within two minutes. Blood pressure measurements are performed at freely-programmable intervals from six to 60 minutes; varying time intervals can also be chosen. AUSCULTATORY BLOOD PRESSURE MEASUREMENT: A miniature pump integrated in the monitor inflates the cuff within a few seconds to a pressure of 160 mmHg or, on subsequent measurements, to 25 mmHg above the last recorded systolic value. On registration of Korotkoff sounds, the cuff pressure is increased in steps of 25 mmHg until the sounds disappear and then deflated in steps of 3 to 5 mmHg. On detection of the first Korotkoff sound, the instantaneous cuff pressure (which is converted to an electric signal by a transducer) is stored as the systolic value. Further deflation then occurs rapidly to 90 mmHg or 10 mmHg above the last measured diastolic value. With higher diastolic values, again, there is an increase in cuff pressure in steps of 25 mmHg until the onset of Korotkoff sounds and then renewed deflation in steps of 3 to 5 mmHg. On disappearance of the Korotkoff sounds, the prevailing cuff pressure is recorded and stored as the diastolic value (Figure 1). To register the Korotkoff sounds optimally, the microphone is positioned above the brachial artery.(ABSTRACT TRUNCATED AT 400 WORDS)

Ambulatory Care↗

Internet based ECG medical information system.

Physiological monitoring of humans for medical applications is well established and ready to be adapted to the Internet. This paper describes the implementation of a Medical Information System (MIS-ECG system) incorporating an Internet based ECG acquisition device. Traditionally clinical monitoring of ECG is largely a labour intensive process with data being typically stored on paper. Until recently, ECG monitoring applications have also been constrained somewhat by the size of the equipment required. Today's technology enables large and fixed hospital monitoring systems to be replaced by small portable devices. With an increasing emphasis on health management a truly integrated information system for the acquisition, analysis, patient particulars and archiving is now a realistic possibility. This paper describes recent Internet and technological advances and presents the design and testing of the MIS-ECG system that utilises those advances.

Database Management Systems↗