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At least 127 records · Page 7Linked to original sources

Technical note: a compact data logger for ambulatory skin temperature measurement.

A miniature, body-worn data logger has been developed for multi-channel recording of small changes in skin surface temperature. The unit has been designed for small size, long battery life and high accuracy together with full programmability and an infra-red (contactless) transfer of parameters and data. Temperature is measured using thermistors with a resolution of 0.005 degrees C and an absolute accuracy of better than 0.05 degrees C. A comprehensive software package running on a laptop PC is used for initial setting of the logger parameters and downloading and displaying the temperature data. The present system records eight channels of temperature at intervals from 30 seconds to 99 minutes. It contains 64 K bytes of non-volatile memory allowing 3274 sets of readings including subject identification, battey status, date and time. The logger size is 55 mm x 31 mm x 9.5 mm and weighs 20 g.

Calibration↗

Potential problems associated with the Rustrak Ranger data logger's data storage technique.

To maximize the 8 kilobyte memory of the Rustrak Ranger data logger, a patented technique called adaptive storage was used. With adaptive storage, the data logger predicts the value of an incoming reading. Based on previously stored readings, the data logger predicts the next reading to be constant, linear, or exponential. If the reading falls outside a window surrounding the predictions, it is stored; otherwise, it is discarded. The size of the window affects the rate at which the readings are stored, and thus is adjusted so data can be collected for the specified sampling time. If the windows are made too large, there is a resultant loss in the resolution of the data. The characteristics of the instrument and the contaminant or physical agent being measured (i.e., air contaminant versus noise) also affect data resolution. In this evaluation, previously collected exposure data (air monitoring) were sent by a computer to the Rustrak Ranger for recording. To determine the effect of the sampling time on resolution, the recorded data were analyzed using two different methods. Sampling times varied from 2 to 120 minutes. These tests showed poor resolution for sampling times as short as 30 minutes, indicating that the Rustrak Ranger may not be suitable for certain types of sampling schemes. However, if used within its limitations, this data logger is a valuable tool for recording real-time industrial hygiene data.

Computer Storage Devices↗

Digital audio tape as a method of storing Doppler ultrasound signals.

Digital audio tape recorders perform significantly better than conventional tape recorders in respect of their frequency response, dynamic range, signal-to-noise ratio, and wow and flutter figures. They also have advantages in terms of their tape size and playing time, and their ability to record additional information as 'sub-codes'. The suitability of DAT recorders as a means for storing ultrasound Doppler signals has been evaluated. The results show that they are an ideal instrument for recording directional Doppler signals, but like conventional tape recorders are not suitable for storing quadrature Doppler signals.

Audiometry↗

Three novel lossless image compression schemes for medical image archiving and telemedicine.

In this article, three novel lossless image compression schemes, hybrid predictive/vector quantization lossless image coding (HPVQ), shape-adaptive differential pulse code modulation (DPCM) (SADPCM), and shape-VQ-based hybrid ADPCM/DCT (ADPCMDCT) are introduced. All are based on the lossy coder, VQ. However, VQ is used in these new schemes as a tool to improve the decorrelation efficiency of those traditional lossless predictive coders such as DPCM, adaptive DPCM (ADPCM), and multiplicative autoregressive coding (MAR). A new kind of VQ, shape-VQ, is also introduced in this article. It provides predictive coders useful information regarding the shape characters of image block. These enhance the performance of predictive coders in the context of lossless coding. Simulation results of the proposed coders applied in lossless medical image compression are presented. Some leading lossless techniques such as DPCM, hierarchical interfold (HINT), CALIC, and the standard lossless JPEG are included in the tests. Promising results show that all these three methods are good candidates for lossless medical image compression.

Computer Storage Devices↗

A cross-sectional international survey of continuous subcutaneous insulin infusion in 377 children and adolescents with type 1 diabetes mellitus from 10 countries.

OBJECTIVE: To document current practices using continuous subcutaneous insulin infusion (CSII) by downloading electronically the 90-d pump data held within the pump memory and relating that to clinical data from children and adolescents in different pediatric diabetes centers from Europe and Israel. METHODS: Data of patients (1-18 yr) treated with CSII in 23 centers from nine European countries and Israel were recorded with the encapture software (PEC International, Frankfurt, Germany). The number of patients who participated was 377 (48% female; mean diabetes duration +/- SD: 6.8 +/- 3.7 yr; age: 12.9 +/- 3.8 yr, preschool n = 33; prepubertal n = 95; adolescent n = 249; CSII duration: 1.6 +/- 1.2 yr; local HbA1c: 8.1 +/- 1.2%). RESULTS: The total insulin dose was lower than previously reported for injection therapy (0.79 +/- 0.20 U/kg/d). Covariance coefficient of daily total insulin was high in all age groups (adolescents 19 +/- 9%, prepubertal 18 +/- 8 and preschool 17 +/- 8). The distribution of basal insulin infusion rates over 24 hr (48 +/- 12% of total dose) varied significantly between centers and age groups. The number of boluses per day (7 +/- 3) was not significantly different between the age groups (average daily bolus amount: 0.42 +/- 0.16 U/kg). The rate of severe hypoglycemia (coma/convulsions) was 12.4 episodes per 100 patient-years and the number of diabetes-related hospital days was 124 per 100 patient-years. DISCUSSION: Pediatric CSII patients show a high variability in their insulin therapy. This relates both to age-dependent differences in the distribution of basal insulin as to the age-independent day-to-day variation in prandial insulin.

Adolescent↗

Maleficent magnets and mangled megabytes.

Personal computers have become common-place in physicians' practices and their use in cardiac pacing for programming and follow-up is increasing. The most commonly used media for mass data storage are ferromagnetic. That the toroidal and bar magnets used to activate reed switches pose a threat to such data is well known but the degree of care necessary in handling magnets around storage media, especially the vulnerable floppy diskettes, is not generally appreciated. The basic principles of magnetic data storage discussed herein elucidate the mechanism of data alteration by extraneous magnetic fields. The properties of the surface coatings, the requirements of applicable industry standards, and the field strengths of the pacemaker magnets suggest that data on diskettes should be secure if kept at least 6-7 cm from an isolated pacemaker magnet. Experiments with typical bar and toroidal magnets demonstrated that data recorded on representative diskettes actually remained unaltered until the magnets were placed < 1 cm from the recording surfaces.

Compact Disks↗

Computer files.

From what has been said, several recommendations can be made for users of small personal computers regardless of which operating system they use. If your computer has a large hard disk not specially required by any single application, organize the disk into a small number of volumes. You will then be using the computer as if it had several smaller disks, which will help you to create a logical file structure. The size of individual volumes has to be selected carefully with respect to the files kept in each volume. Otherwise, it may be that you will have too much space in one volume and not enough in another. In each volume, organize the structure of directories and subdirectories logically so that they correspond to the logic of your file content. Be aware of the fact that the directories suggested as default when installing new software are often not the optimum. For instance, it is better to put different graphics packages under a common subdirectory rather than to install them at the same level as all other packages including statistics, text processors, etc. Create a special directory for each task you use the computer. Note that it is a bad practice to keep many different and logically unsorted files in the root directory of any of your volumes. Only system and important service files should be kept there. Although any file may be written all over the disk, access to it will be faster if it is written over the minimum number of cylinders. From time to time, use special programs that reorganize your files in this way.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer Storage Devices↗

Diagnostic value of stored electrograms in single-lead VDD systems.

UNLABELLED: Evaluation of the quality of atrial sensing is indispensable to monitor the performance of VDD single-lead systems. In addition to counters, a new VDD system offers storage of intracardiac electrograms (EGMs). The clinical contribution of stored EGMs in a VDD pacemaker was prospectively examined in a multicenter study, and the reliability of its counters was evaluated on the basis of EGM information. METHODS: A VDD system (Pulsar 870, Guidant Co.) was implanted in 46 patients with atrioventricular block. EGM storage was activated upon detection of ventricular tachycardia (VT), recurrent premature ventricular complexes (PVCs), and mode switch ("atrial tachy reaction," ATR). Stored EGMs were retrieved before discharge of the patients from the hospital, and at 6-week, 3-month, and 6-month follow-up. RESULTS: A total of 440 stored EGMs were retrieved and analyzed. Of 30 VT episodes detected, 2 (7%) were confirmed, and all others were attributable to ventricular oversensing. One postmortem interrogation documented VT as the cause of sudden death. Of 175 EGMs stored upon detection of PVCs, 43 episodes (25%) were confirmed and 124 (70%) showed intermittent atrial undersensing with spontaneous AV conduction; in 8 episodes (5%) no abnormality was observed. Of 235 episodes stored upon ATR, 82 (35%) were confirmed and 153 were due to atrial oversensing. CONCLUSIONS: (1). Stored EGMs indicated a high percentage (69%) of event misdiagnosis by the pacemaker. Thus, pacemaker counter information without the availability of stored EGMs should be interpreted with caution. (2). Misclassified events are of high clinical importance since they unmask otherwise unsuspected intermittent under- or oversensing.

Aged↗

Image archival technologies.

A typical radiology department can create many gigabytes of image data per day and as much as 1 terabyte of data per year. Archiving and accessing this much data are substantial problems. One solution is data compression, which decreases data storage requirements and increases the rate of data transfer; however, standards are not yet available. Other solutions involve improvements in archival media. Jukebox subsystems allow automated access to multiple units. Digital magnetic tape, the standard medium, can store large amounts of information and enables easy updates or replacements; more practical technologies have been introduced in recent years. Digital videotape allows storage of digital video data and features a high rate of data transfer. Optical disks, now the preferred permanent archival medium, have a large storage capacity and provide excellent long-term stability. Optical tape is also being investigated as a solution to the archiving dilemma. Which technology to choose depends on many factors, including needs of the institution and the cost, stability, transfer time, and storage capacity of the system.

Computer Storage Devices↗

Radiation risk and cost-benefit analysis of a paediatric radiology procedure: results from a national study.

A national study was performed to investigate radiation doses and associated risks to patients during X-ray fluoroscopy-guided small intestinal biopsies in the investigation of coeliac disease. Thermoluminescent dosemeters (TLD) and questionnaires were sent to 42 of the 43 paediatric departments in Sweden performing these biopsies. During the study period (2 x 3 weeks) 257 biopsies were recorded, representing about 10% of annually performed paediatric investigations. The results show that the absorbed dose during biopsy ranged from 0.04 mGy to 23.8 mGy (mean 1.87 mGy). The fluoroscopy time ranged from 2 s to 663 s (mean 60 s). The collective dose from the procedure amounts to 4.7 manSv year(-1). Thus, the annual excess cancer mortality, including severe hereditary effects, can be estimated at 0.6-0.7 cases per year. However, significant dose saving can be obtained by proper choice of sedation and biopsy equipment.

Adolescent↗

Rescuing corrupted gel files from Model 377 and 373 DNA Sequencers.

Automated DNA sequencing requires the intensive use of computers to handle the large amount of data taken. When a computer failure occurs and the data are no longer accessible, all the expense and effort that went into the sequencing experiment is lost. By using the data storage architecture of Macintosh computers to our advantage, we may prevent this loss in the case of automatic sequencers from PE Applied Biosystems. The software required to allow the experimenter to do this has been written and is available free of charge.

Automation↗