Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Systems Analysis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed2005

Quantitative determination of total lipid hydroperoxides by a flow injection analysis system.

A flow injection analysis (FIA) system coupled with a fluorescence detection system using diphenyl-1-pyrenylphosphine (DPPP) was developed as a highly sensitive and reproducible quantitative method of total lipid hydroperoxide analysis. Fluorescence analysis of DPPP oxide generated by the reaction of lipid hydroperoxides with DPPP enabled a quantitative determination of the total amount of lipid hydroperoxides. Use of 1-myristoyl-2-(12-((7-nitro-2-1,3-benzoxadiazol-4-yl)amino) dodecanoyl)-sn-glycero-3-phosphocholine as the internal standard improved the sensitivity and reproducibility of the analysis. Several commercially available edible oils, including soybean oil, rape-seed oil, olive oil, corn oil, canola oil, safflower oil, mixed vegetable oils, cod liver oil, and sardine oil were analyzed by the FIA system for the quantitative determination of total lipid hydroperoxides. The minimal amounts of sample oils required were 50 microg of soybean oil (PV = 2.71 meq/kg) and 3 mg of sardine oil (PV = 0.38 meq/kg) for a single injection. Thus, sensitivity was sufficient for the detection of a small amount and/or low concentration of hydroperoxides in common edible oils. The recovery of sample oils for the FIA system ranged between 87.2+/-2.6% and 102+/-5.1% when PV ranged between 0.38 and 58.8 meq/kg. The CV in the analyses of soybean oil (PV = 3.25 meq/kg), cod liver oil (PV = 6.71 meq/kg), rapeseed oil (PV = 12.3 meq/kg), and sardine oil (PV = 63.8 meq/kg) were 4.31, 5.66, 8.27, and 11.2%, respectively, demonstrating sufficient reproducibility of the FIA system for the determination of lipid hydroperoxides. The squared correlation (r2) between the FIA system and the official AOCS iodometric titration method in a linear regression analysis was estimated at 0.9976 within the range of 0.35-77.8 meq/kg of PV (n = 42). Thus, the FIA system provided satisfactory detection limits, recovery, and reproducibility. The FIA system was further applied to evaluate changes in the total amounts of lipid hydroperoxides in fish muscle stored on ice.

Animals↗
PubMed1999

Cataract Image Analysis System.

A system for sequential colour video capture and analysis of lens opacities is described. A sensitive RGB (Red-Green-Blue) camera is coupled to a 486 DX2/66 IBM-compatible computer to obtain high-resolution images of cataracts. Vacuoles, retro-dots, suture opacities, wedge opacities, cortical and posterior subcapsular opacities and nuclear sclerosis can be digitised and subjected to various analysis systems and colour prints obtained. The size and number of vacuoles and opacities can be determined by selecting areas of interest, and line tracings of whole lens, isolated opacities or nuclear sclerosis can be separated by analysis into 16.8 million plus colour gradients. The Cataract Image Analysis System represents a precise and new digitised procedure for cataract documentation and may be of value in determining cataract progression and evaluation of medical therapy.

Cataract↗
PubMed2001

Comparison of capillary electrophoresis sequencing with the new CEQ 2000 DNA Analysis System to conventional gel based systems for HIV drug resistance analysis.

To date the majority of sequencing technologies have been based on use of gel plates. In this study sequencing by capillary electrophoresis for HIV-1 genotyping on the CEQ 2000 sequencer (Beckman Coulter Inc.) has been investigated and compared to an 'in house' protocol on the Prism-377 sequencer (Applied Biosystems) and to the HIV-1 TruGene kit (Visible Genetics Inc.), two gel plate-based systems. Plasma from 20 HAART-treated patients with virological failure were analyzed for protease (PR) and reverse transcriptase (RT) genes. A total of 520 RT codons (26/patient) and 360 PR codons (18/patient) related to antiretroviral drug resistance were evaluated. The overall agreement between CEQ 2000 and Prism-377 results was 100% for the RT and PR primary and secondary mutations. The overall agreement between CEQ 2000 and TruGene was 100% for primary and > or =97% for secondary mutations. Discrepant results would have never led to errors in genotype interpretation. Performances for a 24 patients/week/one technician genotyping throughput were analyzed. For Prism-377, TruGene and CEQ 2000, manual processing required 5, 4 and 2,5 days, sequence data analysis needed additional 3, 1 and 2 days and cost/patient was approximately 49, 214 and 39 $, respectively. The CEQ 2000 sequencer offers a reliable alternative for fast and cost effective HIV drug resistance analysis.

Anti-HIV Agents↗
PubMed1984

A multidetector alpha spectroscopy analysis system.

This document describes the attributes of an alpha spectroscopy counting and analysis system called Low Level Pulse Height Analysis (LLPHA). It was developed for multi-sample alpha spectroscopy analysis. The LLPHA system is controlled by a MIK-11/2 microcomputer with 28K of memory and uses a double-density, dual floppy disk for data storage. Detectors are interfaced to the computer via CAMAC (Computer Automated Measurement and Control) equipment. The system simultaneously supports 32 active and independent surface-barrier alpha-particle detectors. It operates with the total collection rate of up to 300 counts/sec from all active detectors, using 128 channels per spectrum and a dynamic energy range of 1.4 MeV. The system is not limited, however, to these conditions. In addition to spectral acquisition, the system provides analysis functions which include peak identification, curve-smoothing, integration, linear and logarithmic scale graphics, and corrections for base-line shift, dead-time, and background counts. These functions can be implemented while other spectra are being collected. The LLPHA system represents a highly cost-effective means of acquiring alpha spectrometric data from a large number of samples simultaneously and with rapid data analysis capability.

Alpha Particles↗
PubMed2005

Performance characteristics of gas analysis systems: what we know and what we need to know.

It is important that sources of variation in gas analysis measurements are identified and described in an accurate and informative manner. In this paper, we discussed the potential sources of error, which should be considered in any measurement study on gas analysis systems. We then covered how errors in various terms associated with gas laws propagate to outcome measurements of gas exchange to help quantify the relative importance of sources of error. Finally, we performed a literature survey to explore the statistical methods researchers have employed to arrive at conclusions on the performance characteristics of gas analysis methods. We found examples of excellent practice in the literature, but there were also gaps in the knowledge of error in gas analysis systems. Consequently, we supplied guidelines for future method comparison studies. These guidelines included (i) a sample size of at least 40 participants and the citation of confidence intervals, (ii) a description of the relationships between systematic and random errors and the size of measured value, (iii) the parallel examination of test-retest error within a method comparison study, and (iv) an a priori-made judgement on how much systematic and random error between methods is acceptable for practical applications. We stressed that this judgement should be based on expert-agreed position statements about acceptable error, which unfortunately have yet to be formulated for gas analysis systems.

Breath Tests↗
PubMed1994

Features of the nutrient database and analysis system for the Modification of Diet in Renal Disease Study.

This article describes the features of the nutrient database and analysis system developed for the Modification of Diet in Renal Disease (MDRD) Study and outlines the development process itself, an example of tailoring a database and analysis system for a complex, long-term clinical trial. The MDRD Study was a 15-center trial for men and women aged 18 to 70 years with chronic renal disease who were not on dialysis and who had not had a kidney transplant. The effects of three levels of protein and phosphorus intake and two levels of blood pressure management were assessed on the rate of decline in kidney function. This paper describes the development, structure, contents, and application of the nutrient database and analysis system that was used to enter, analyze, and report the MDRD Study dietary data.

Adolescent↗
PubMed2006

A novel method of producing a repetitive dynamic signal to examine reliability and validity of gait analysis systems.

Gait dysfunction is a common functional complaint of clients who seek medical care. Gait dysfunction can be caused by musculoskeletal disorders such as osteoarthritis or fractures, or it can be caused by neuromuscular disorders such as multiple sclerosis or cerebrovascular accident. Decisions made by health care providers working with these clients could be enhanced by the availability of valid and reliable gait measurement. Valid and reliable gait measurement is possible with laboratory-based motion analysis systems, but these are not universally available. Several portable systems collect footfall data and provide a relatively inexpensive alternative to sophisticated motion analysis systems. However, data collected by these portable systems cannot be used with confidence because of the lack of verification of the validity and reliability of the data they collect about movement. This paper describes a novel method of examining test-retest reliability and concurrent validity that produces a signal with minimal variation. To produce repetitive distance and timing events, a cylindrical weight was rolled across the field of both the laboratory motion analysis system and the system to be evaluated. Measures of the weight's movement were taken simultaneously with both systems. A reference point was chosen to allow for comparison between the systems. The spatial measure that was compared between systems was the horizontal distance between successive repetitions of the reference point's vertical position. The temporal measure that was compared between systems was the time between successive repetitions of the reference point's vertical position. The method described in this paper provides a minimally variable repetitive signal that can be used to investigate concurrent validity of gait analysis systems.

Biomechanical Phenomena↗
PubMed2004

Accuracy and reliability of a Cosmed K4b2 portable gas analysis system.

The purpose of this study was to assess the validity and reliability of a Cosmed K4b2 portable telemetric gas analysis system. Twelve physically fit males performed a treadmill running session consisting of an easy 10 min run, a hard 3 min run and a 1 min sprint (with rest periods of 10 min separating each run), on four separate occasions. Sessions were identical with the exception of the apparatus used to measure VO2. During two (test-retest) sessions a Cosmed K4b2 portable gas analysis system was used; in another, a laboratory metabolic cart and, in one session, both systems were used to measure VO2 simultaneously. Comparison of Cosmed K4b2 and metabolic cart measurements in isolation revealed significantly (p < 0.05) increased values of VO2, VCO2, FE CO2 (except FE CO2 at 10 min) and lower values of FE O2 for each run duration by the Cosmed system. Linear regression equations to predict metabolic cart results from Cosmed values were, respectively; cart VO2 = 0.926 (Cosmed VO2-0.227 (r2 = 0.84) and cart VCO2 = 1.057 (Cosmed VCO2-0.606 (r2 = 0.92). Bland-Altman plots and comparison of the test-retest cosmed measurements revealed that the K4b2 system showed good repeatability of measurement for measures of VE, VO2 and VCO2, particularly for 10 min and 3 min tests (ICC = 0.7-0.9, p < 0.05). In conclusion, the Cosmed K4b2 portable gas analysis system recorded consistently higher VO2 and VCO2 measurements in comparison to a metabolic cart. However, satisfactory test-retest reliability of the system was demonstrated.

Adult↗
PubMed2006

Increasing the number of gait trial recordings maximises intra-rater reliability of the CODA motion analysis system.

OBJECTIVE: This study investigates the optimum number of gait trial recordings to maximise intra-rater reliability with the CODA motion analysis system in a normal population. Potential sources of variability in test-retest experimental procedures will be discussed. BACKGROUND: The most recent study by [Maynard V, Bakheit AMO, Oldham J, Freeman J. Intra-rater and inter-rater reliability of gait measurements with CODA mpx30 motion analysis system. Gait Posture 2003;17:59-67] that evaluated the Cartesian Optoelectronic Dynamic Anthropometer (CODA) motion analysis system exhibited poor correlation for intra-rater reliability of kinematic and kinetic parameters. It is unknown what the optimum number of gait trials is required during testing to represent an individuals gait pattern during normal walking. DESIGN: Ten healthy subjects (mean 28.5 years) were tested on two occasions by an experienced well trained rater during normal walking to establish intra-rater reliability using 1-2, 1-4, 1-6, 1-8, and 1-10 gait trial recordings to represent the mean. The 3D kinematic, kinetic parameters of hip, knee and ankle joints and spatio-temporal parameters were recorded during normal walking. Intra-class correlation coefficient and Bland and Altman limits of agreement were chosen to analyse the results. RESULTS: Spatio-temporal parameters exhibited least test-retest variability, as measurement of only two gait trials to represent the mean produced similar variability in test-retest as when higher numbers of trials were measured. Kinematic parameters were more variable than kinetic while for both variability decreased with increasing numbers of trials measured and would advocate measuring 10 gait trials for future analysis when measuring these parameters. CONCLUSIONS: Generally intra-rater reliability improves when larger number of gait trial recordings represent a subject's gait.

Adult↗
PubMed1988

Quantitative evaluation of coat-color patterns in artificially produced chimeras of the mouse by means of a microcomputer-based video-image analysis system.

The possible application of microcomputer-based video-image analysis systems for the quantitative description of coat-color patterns in artificially produced chimeras and genetic mosaics of mice was investigated using a program developed by the author. This system is capable of extracting, from sampled images of pelts, the morphometric image features as defined by Pratt [1978] that are essential to the quantitative description of coat-color patterns in these animals. It does so with reasonable accuracy and speed and at low cost. No description of any similar system has been published in the literature. Performance of our system is described using C3H/HeJ----BALB/c chimeras as examples. The complex phenotypic expression of hair pigmentation in mice makes the use of a video-image analysis system like this one essential to evaluate the morphometric parameters of the patterns (e.g., the mixing ratios between the two components, the number of different-colored stripes, etc.) more precisely and reproducibly than has been done yet in the literature. The results indicate that the number of melanoblast clones in mice, as estimated from the number of minimal recognizable stripes (MRS), might be considerably larger than previously indicated; the figure presently obtained, i.e., 22.3 +/- 2.16 unilaterally in terms of the hypothetical maximum number of stripes (HMNS) (28.73 +/- 1.55, after correction for the random clumping) in the thoracicolumbar region of the mouse closely approximates the number of the somites in that region. Concerning the degree of mixing between the two components, it was proposed that the unmixed portion of the components derived from one strain increases in proportion to the second power of the increase in the relative total content of the same components. Work is in progress in our laboratory to analyze a large number of the chimeric pelts using the system described in this paper.

Animals↗
PubMed1980

Applicability of white-noise nonlinear system analysis to the peripheral auditory system.

A functional series is capable of describing the input-output relationship of a general class of systems, linear or nonlinear. Wiener and his associates demonstrated methods by which these functionals could be measured from the response of the system to white noise. This paper is a critique of the application of this functional series approach to the measurement of the input-output relationship of the peripheral auditory system. The Wiener functionals are shown to be dependent on the parameters of the white noise used to measure them. The approximation of the output of a system by a truncated Wiener series is shown to have unpredictable error properties when inputs other than white Gaussian noise are used. Estimates of the Wiener functionals using the white-noise approach do not converge when the system has a point process output (e.g., spike train output).

Humans↗
PubMed2004

[An analysis system of physical training workload based on Polar Sports Tester].

The polar sports tester made in Finland as one of the most widespread instruments in physical training is of importance for sports training. In this paper, we have developed a set of system for analysis of physical training workload using the measured data of the Polar Sports Tester, and have established a set of analysis indices and reports of the physical training workload, including five categories and 127 quantitative indices. It can reflect the distribution of physical workload and provide a series of parameters for coaches to direct scientific training and raise sport level.

Adaptation, Physiological↗
PubMedDate not supplied

A new microcomputer-controlled neutron activation and analysis system. Description and applications for the analysis of bioenvironmental specimens.

A microcomputer-controlled irradiation and measurement system and a microprocessor-controlled sample changer have been installed at the SLOWPOKE-2 Facility at the Royal Military College of Canada (RMC). These systems can provide the gamut of instrumental neutron activation analysis (INAA) techniques for the analyst. Custom software has been created for system control, data acquisition, and off-line spectral analysis using programs that incorporate Gaussian peak-fitting methods of analysis. The design and use of the equipment is discussed, and the performance is illustrated with results obtained from the analysis of marine sediment and biological reference materials.

Microcomputers↗