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PubMed1990

New developments in the Life Table Analysis System of the National Institute for Occupational Safety and Health.

In the 1970s, the National Institute for Occupational Safety and Health developed a Life Table Analysis System to analyze occupational cohort studies. We have updated the original system by adding two new features: direct standardization with a test for linear trend, and analyses by lagged exposure (either duration of exposure or cumulative exposure). We have also updated US reference rates through 1989. The updated systems and documentation (version F) are available upon request. In collaboration with the National Cancer Institute, we have also developed multiple cause-of-death rate files, which consider contributory as well as underlying cause. These files (also available upon request) will enable investigators to derive the expected prevalence of diseases at death, which can then be compared with the observed prevalence in an exposed cohort. Work is currently underway to produce a personal computer version of the Life Table Analysis System.

Cause of Death↗

PubMed2004

The application of an automated allele concordance analysis system (CompareCalls) to ensure the accuracy of single-source STR DNA profiles.

A powerful method for validating a scientific result is to confirm specific results utilizing independent methodologies and processing pathways. Thus, we have designed, developed and validated an automated allele concordance analysis system (CompareCalls, patent pending) that performs comparisons between two independent DNA analysis platforms to ensure the highest accuracy for allele calls. Application of this system in a quality assurance role has shown the potential to eliminate greater than 90% of the STR analysis required of a DNA data analyst. While this system is broadly applicable for use with any two independent STR analysis programs, either prior to or following human data review, we are presenting its application to data generated with the ABI Prism Genotyper software system versus data generated with the SurelockID system. With the automated allele concordance analysis system, the GeneScan DNA fragment data generated from an ABI 377 gel image are analyzed in two independent pathways. In one analysis pathway, the GeneScan data are imported into Genotyper software where STR labels are assigned to the fragment data based upon the criteria of the Kazam 20% macro. The "Kazam" macro provided with the Genotyper program works by labeling all peaks in a category (or locus) and then filtering (or removing) the labels from peaks, such as those in stutter positions, that meet predefined criteria. In the second pathway, the GeneScan data are imported into the SurelockID analysis platform where STR labels and error messages are assigned to the fragment data based upon hard-coded allele calling criteria and quality parameters. The resulting STR allele calls for each analysis platform are then compared, utilizing the automated allele concordance analysis system. Any differences in the STR allele calls between the two systems are flagged in a discordance report for further review by a qualified DNA data analyst. The automated allele concordance analysis system guides the DNA data analyst to the discordant data generated by either analysis platform. Additionally, the analyst is also directed to data that are of less than pristine quality which may have an increased potential for errors in interpretation by either analysis platform or by a human DNA data analyst. Implementation of an automated allele concordance analysis system will yield high-quality data for CODIS and free the human DNA data analyst to perform other critical duties within the laboratory.

Alleles↗

PubMedDate not supplied

On-line determination of biomass in a microalga bioreactor using a novel computerized flow injection analysis system.

A flow injection analysis (FIA) device has been developed, which is able to assay successfully for biomass in a microalga bioreactor. The device is fully computerized and is operated via diluting small aliquots of the culture followed by measuring optical density (OD); this figure is then accurately correlated with biomass, in terms of both cell number and ash-free dry weight, during the entire culture time. Furthermore, the device is not expensive, is highly versatile, and is easy to operate owing to specifically developed, user-friendly software. The growth rate and biomass productivity of Pavlova lutheri, cultivated under batch and semicontinuous modes, were monitored as experimental testing model.

Biomass↗

PubMed1990

DNA ploidy in breast lesions. A comparative study using two commercial image analysis systems and flow cytometry.

DNA ploidy determinations on a series of 24 breast specimens were performed independently utilizing flow cytometry (FCM) and two separate commercially available computerized image analysis systems for image cytometry (ICM). The tissues analyzed were obtained from 20 carcinomas, 2 benign neoplasms and 2 benign reductive procedures. The results showed a close correlation between the DNA indices (DIs) obtained by all methods in 14 of the 24 cases. In four cases, all methods showed aneuploid peaks, but with differing DIs. In six cases (two benign and four malignant) FCM showed diploidy while ICM showed peridiploid cell populations. The results obtained with the two image analysis systems were in agreement for 20 of the 24 cases. ICM is an acceptable alternative to FCM for reproducible ploidy analysis. ICM-based measurements have the advantage of the visual discrimination of abnormal cells and therefore may have a greater sensitivity in identifying small aneuploid populations. Populations with DIs in the range of 1.0 to 1.3 need to be assessed carefully in ICM-based determinations due to the potential that these "aneuploid" peaks may represent shifted diploid populations.

Breast Diseases↗

PubMed2005

Accuracy, reliability, and validity of a spatiotemporal gait analysis system.

BACKGROUND: Making evidence-based decisions in the clinical management of gait dysfunction requires the ability to measure spatiotemporal gait variables validly and reliably. This study examined the accuracy, reliability, and validity of a clinical gait analysis system that is relatively inexpensive and portable, the GaitMat II (GM). METHODS: The trustworthiness of measures taken with the GM was investigated by comparing the placement of the switches on three different GM systems. Measures taken with the GM system were compared with the same measures taken simultaneously with the Vicon motion analysis system, using a repetitive dynamic signal presented to both systems. FINDINGS: Variability was present in the placement of switches on the surfaces of different GM systems. The variability in switch placement was much less than the normal variability of most gait variables measured with the GM. Excellent agreement was found between the GM and Vicon systems for timing variables but poor agreement was found for distance variables. The mean difference between the GM and Vicon measures for distance variables would have little clinical significance in adults for distance measures such as step length or stride length. CONCLUSION: The results of these studies support the reliability and validity of the GaitMat II as a clinical gait analysis tool.

Biomechanical Phenomena↗

PubMed2006

Using system analysis to build a safety culture: improving the reliability of epidural analgesia.

BACKGROUND: A potentially dangerous situation was revealed by an incident report describing the use of an inappropriate device to administer post-operative epidural analgesia to a patient on a surgical ward. The incident occurred in a 1200-bed university affiliated tertiary hospital (Geneva University Hospitals, HUG) and involved three clinical departments: anaesthesiology, the surgical intensive care unit and urology. METHODS: A multidisciplinary system analysis was carried out to identify care-delivery problems and contributory factors. Corrective actions were devised on the basis of their ability to prevent and absorb unsafe situations. RESULTS: The system analysis identified three care-delivery problems in relation to the management of epidural analgesia. It enabled medical and nursing managers to adopt an interdepartmental set of corrective actions: a common protocol for post-operative epidural analgesia, leading to the exclusive use of patient-controlled epidural analgesia (PCEA) pumps; greater availability of the patient-controlled pumps; the dissemination of guidelines; permanent proactive training of nurses by the acute-pain team; the clarification of medical responsibilities; and a common help-line phone number for all surgical departments. DISCUSSION: The analysis provided a convincing exposure of various care-delivery problems and their corresponding contributory factors, as well as an opportunity to address a systemic issue in a multidisciplinary way. By thus facilitating decisions and corrective actions, the analysis was instrumental in strengthening our safety culture.

Adult↗

PubMed1988

A microcomputer based automated, quantitative coronary angiographic analysis system.

Rapid and accurate assessment of coronary artery stenotic severity is important in therapy and understanding of coronary artery disease. Since automated systems minimize prejudice and variations in analysis, we developed an automated, quantitative coronary analysis system utilizing an IBM PC-XT computer. Film images (35 mm) were cine-to-video converted and subsequently digitized by an IBM PC-XT computer. Given an approximate center line, the computer automatically detected edges, corrected for X-ray magnification, and calculated arterial dimensions. On objects of known dimensional sizes, the correlation coefficient between actual and calculated dimensions was 0.996 (p less than 0.01) with a standard error of estimate of 0.07 mm and +/- 3.0% reproducibility. For objects less than 1 mm in diameter, the standard error of estimate was 0.05 mm with +/- 4.1% reproducibility. However, with minimal contrast material (25%), the standard error of estimate increased to 0.20 mm with +/- 7.2% reproducibility. The results indicate that automated, quantitative coronary angiography can be achieved using an inexpensive IBM PC-XT based system, provided that the vessels are adequately opacified.

Adult↗

PubMed1999

Qualitative and quantitative analysis of voice onset by means of a multidimensional voice analysis system (MVAS) using high-speed imaging.

High-speed filming is one of the most informative methods for assessing voice physiology data. Tracing high-speed images of the glottis provides quantitative parameters such as the glottal area and the glottal width function. By way of example, a number of studies are discussed which extract quantitative data from high-speed images showing voice onsets. Furthermore, a new computer system (MVAS; multi-dimensional voice analysis system) is presented that synchronously displays a laryngoscopic high-speed film, the electroglottographical signal, and several acoustic analyses of the recorded voice sample. The automatic measurement of glottal width and glottal area from the laryngoscopic images is also provided. Looking at former studies and our analyses of voice onsets reveals a tremendous intersubject and even intrasubject variability (different prephonatory closure, different time span until full amplitude is reached, different open quotient).

Equipment Design↗

PubMed2005

Reliability of segmental accelerations measured using a new wireless gait analysis system.

The purpose of this study was to determine the inter- and intra-examiner reliability, and stride-to-stride reliability, of an accelerometer-based gait analysis system which measured 3D accelerations of the upper and lower body during self-selected slow, preferred and fast walking speeds. Eight subjects attended two testing sessions in which accelerometers were attached to the head, neck, lower trunk, and right shank. In the initial testing session, two different examiners attached the accelerometers and performed the same testing procedures. A single examiner repeated the procedure in a subsequent testing session. All data were collected using a new wireless gait analysis system, which features near real-time data transmission via a Bluetooth network. Reliability for each testing condition (4 locations, 3 directions, 3 speeds) was quantified using a waveform similarity statistic known as the coefficient of multiple determination (CMD). CMD's ranged from 0.60 to 0.98 across all test conditions and were not significantly different for inter-examiner (0.86), intra-examiner (0.87), and stride-to-stride reliability (0.86). The highest repeatability for the effect of location, direction and walking speed were for the shank segment (0.94), the vertical direction (0.91) and the fast walking speed (0.91), respectively. Overall, these results indicate that a high degree of waveform repeatability was obtained using a new gait system under test-retest conditions involving single and dual examiners. Furthermore, differences in acceleration waveform repeatability associated with the reapplication of accelerometers were small in relation to normal motor variability.

Acceleration↗

PubMedDate not supplied

A systems analysis approach to planned change in a clinical psychiatric program.

In health car facilities, systems studies are commonly conducted as ivory-tower operations with minimal impact and little practical result. A real-life case study was presented to demonstrate how it can be used effectively in a collaborative manner to implement constructive change. Systems Analysis techniques were succe-sfully used with the staff of a psychiatric ward to plan for a satellite outpatient treatment program. The focus was on collaboration to help the ward to obtain objective information for decisions concerning the need for changes in their existing system.

California↗

PubMed1997

Accuracy of reconstructed angular estimates obtained with the Ariel Performance Analysis System.

BACKGROUND AND PURPOSE: Three-dimensional computerized gait analysis continues to grow in use among physical therapists and other clinical specialists interested in quantitative data regarding human ambulation. This study documented the accuracy of reconstructed angular estimates under static and dynamic conditions using the Ariel Performance Analysis System. METHODS: Angular velocity was systematically increased by raising the release position of a T-shaped pendulum. Angular velocities were examined by releasing the pendulum from four angles (0 degree-static, 45 degrees, 90 degrees, and 120 degrees). Twelve reference angles were estimated over 20 autodigitized frames for 10 trials at each release position. Intraclass correlation coefficients (ICCs) and analysis-of-variance (ANOVA) procedures were used to test the hypothesis that the error of angular estimates grows with increasing angular velocity. RESULTS: Mean errors of the reconstructed angles were consistently within +/- 1.0 degree, regardless of angular velocity. An ANOVA revealed a statistically significant angular velocity effect, characterized by release position. The 90-degree release position produced the greatest error, followed by the 120-, 45-, and 0-degree release positions. The error was not significantly different between the 120- and 45-degree release positions. Intraclass correlation coefficients greater than .90 were found for all frame-to-frame angular velocities, except for the 90-degree release position. The angle estimates consistently underestimated the reference angles, regardless of release position. CONCLUSION AND DISCUSSION: The results suggest that clinically accurate angular estimates can be obtained across the range of angular velocities used in this study.

Biomechanical Phenomena↗

PubMed1994

Monte Carlo modelling of neutron depth dose distributions in optimizing prompt gamma in vivo neutron activation analysis systems.

Optimization of prompt gamma in vivo neutron activation analysis systems is best achieved using Monte Carlo simulation. In this study the modelling of the dimensions and materials for source holders and collimators is described and compared with experimentally derived results where feasible. Results show that valid depth doses are obtained by modelling only the central part of an IVNAA system and that the use of borated paraffin as a reflector provides acceptable thermal fluence and depth dose.

Americium↗

PubMed1978

Systems analysis of an aeromedical evacuation mission.

The author applies general systems theory to the analysis of a social system. Through an examination of information processing in an aeromedical evacuation mission, more meaningful levels of coordination evolve. Thus system analysis, as applied here, is an approach used to not only describe an organization but, more importantly, to clearly discern the interrelationships inherent in an activity of major significance such that change or improvement, if needed, may the more readily result.

Aerospace Medicine↗

PubMed1982

Some extensions to the GELLAB two-dimensional electrophoretic gel analysis system.

Several important extensions to the GELLAB 2D electrophoresis gel analysis system are discussed, including concepts that lead to the generation of consistent gel maps for a particular cell line, as illustrated by some recent results for the P388D1 cell system, GELLAB is an interactive graphics computer system that facilitates (a) image accessioning, (b) spot-data extraction from the image with position and density quantitation, (c) pairing of corresponding spots between gels, and (d) spot analysis for a large number of corresponding spots (over 3000 per gel) for up to 128 gels. Multiple gels are accessioned into the system used to create a composite gel data base. These then may be partitioned into multiple classes of gels and searched for statistically significant interclass spot differences, which can be visualized in reference map images of selected spot sets as well as mosaic images of particular spots in all gels. In addition to the visual feedback that is available during the gel analysis, various statistical, numerical, and other displays may be generated in the CGELP interactive program of the GELLAB system.

Animals↗

PubMed1990

Evaluation of the semi-automated Autosperm semen analysis system. I. Accuracy and comparison with the conventional method and the automated Hamilton-Thorn system.

The accuracy of measurements by the semi-automated Autosperm (Amsaten N.V.S.A. Corp., DePinte, Belgium) semen analysis system was assessed by recounting and manually tracking sperm recorded on videotape during analysis of 51 ejaculates. Mean inaccuracies in the analysis of sperm concentration and percentage motility were 15% and 22%, respectively. Measurements of sperm movement characteristics relied on the skill of the operator and discrepancies (means around 10%, maximum 57% to 184%) depended on the straightness of sperm paths. Although less expensive than the fully automated system, semen analysis by Autosperm is a subjective and labor-intensive method. Furthermore in comparison, data obtained using Autosperm also provide less information, and agreements of matched data with those obtained by the conventional methods were not significantly better.

Humans↗

PubMed1999

[Human motion analysis system based on common video-camera].

A new human motion analysis system based on common video-camera is introduced in this paper. The image processing technique is used to recognize and track anatomic landmarks, which makes data processing more quickly and accurately. The system is cost-effective and can be easily operated because the common video-cameras instead of special instruments are used. Furthermore, the system can also be used for detection and analysis of other low-speed moving objects.

Algorithms↗

PubMed1997

The effect of a plaster cast on lumbosacral joint motion. An in vivo assessment with precision motion analysis system.

STUDY DESIGN: This study was conducted to assess the effect of a plaster cast on the mobility of the lumbosacral joint in 10 patients with chronic low back pain. During static and dynamic exercises, movements between the proximal vertebra (L4 or L5) and the sacrum were registered in 10 patients without a support and after the application of a plaster cast, and with and without unilateral hip immobilization, respectively. OBJECTIVES: To investigate whether plaster casts actually immobilize the lumbosacral joint. SUMMARY OF BACKGROUND DATA: The presumed stabilizing effect of a lumbar orthosis on the lumbosacral joint has been the subject of many studies in the past years, and contradictory reports have been published. METHODS: The measurements were performed by means of Precision Motion Analysis System, an optoelectronic three-dimensional motion analysis system using infrared light. The patients were asked to perform maximal spinal flexion to extension, maximal pelvic tilt (static test conditions), and to walk within the measurement volume (dynamic test condition). This procedure was repeated with the patients wearing a plaster cast with and without unilateral hip fixation. Mobility was expressed in translations and rotations around three axes. For statistical analysis, repeated measurements two-way analysis of variance was used. RESULTS: Considerable rotations were found only in the sagittal plane. Both plaster casts appeared to decrease mobility during the static test conditions. During the dynamic test condition, however, no significant decrease of mobility of the lumbosacral joint by either of the casts could be observed. In both cast conditions, considerably more sagittal rotation was found during walking than with the other two exercises. CONCLUSION: In the sagittal plane, a plaster cast with or without unilateral hip immobilization can decrease motion during spinal flexion-extension. This stabilizing effect on the lumbosacral joint could not be observed during walking.

Adult↗

PubMed2001

Automated metabolic gas analysis systems: a review.

The use of automated metabolic gas analysis systems or metabolic measurement carts (MMC) in exercise studies is common throughout the industrialised world. They have become essential tools for diagnosing many hospital patients, especially those with cardiorespiratory disease. Moreover, the measurement of maximal oxygen uptake (VO2max) is routine for many athletes in fitness laboratories and has become a defacto standard in spite of its limitations. The development of metabolic carts has also facilitated the noninvasive determination of the lactate threshold and cardiac output, respiratory gas exchange kinetics, as well as studies of outdoor activities via small portable systems that often use telemetry. Although the fundamental principles behind the measurement of oxygen uptake (VO2) and carbon dioxide production (VCO2) have not changed, the techniques used have, and indeed, some have almost turned through a full circle. Early scientists often employed a manual Douglas bag method together with separate chemical analyses, but the need for faster and more efficient techniques fuelled the development of semi- and full-automated systems by private and commercial institutions. Yet, recently some scientists are returning back to the traditional Douglas bag or Tissot-spirometer methods, or are using less complex automated systems to not only save capital costs, but also to have greater control over the measurement process. Over the last 40 years, a considerable number of automated systems have been developed, with over a dozen commercial manufacturers producing in excess of 20 different automated systems. The validity and reliability of all these different systems is not well known, with relatively few independent studies having been published in this area. For comparative studies to be possible and to facilitate greater consistency of measurements in test-retest or longitudinal studies of individuals, further knowledge about the performance characteristics of these systems is needed. Such information, along with the costs and the common features associated with these systems, may aid physicians and scientists to select a system that is best suited to their requirements and may also improve the quality of these frequently-reported physiological measures.

Automation↗