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Results for “Systems Analysis”

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At least 37 records · Page 2Linked to original sources
PubMed1990

Evaluation of the semi-automated Autosperm semen analysis system. II. Comparison with conventional method, time-exposure photomicrography, and automated CellSoft system.

Semen analysis results obtained by a recently developed semi-automated Autosperm system (Amsaten N.V.S.A. Corp., De Pinte, Belgium) were compared with those obtained by the conventional, time-exposure photomicrographic, and automated CellSoft system (Cryo Resources Inc., New York, NY) analyses. The Autosperm system either over- or underestimated the sperm concentration in comparison with the conventional analysis and more often underestimated the sperm concentration in comparison with the automated CellSoft system analysis. Comparison of the results for percent sperm motility by the conventional and Autosperm analyses showed that the latter tended to underestimate the percentage of fast-swimming spermatozoa and overestimate the percentage of slow-swimming spermatozoa. There were considerable variations in the measurement of sperm movement characteristics between the Autosperm and time-exposure photomicrographic and automated CellSoft system analyses, respectively. These findings demonstrate that the performance of the Autosperm system does not agree well with those of the currently available methods employed in the present study. Part of the disagreement in measurements of sperm parameters could be because of the subjective elements inherent in the semi-automated Autosperm analysis.

Humans↗
PubMedDate not supplied

Novel flow injection analysis systems for drug analysis.

Flow injection analysis (FIA) has become a versatile tool for rapid and automated analyses. As its capabilities have increased, so have the complexity and operation of the apparatus. We have been investigating ways to simplify both the apparatus and the application of injection techniques. A novel cam-driven syringe pump and the development of sequential injection analysis (SIA) are reviewed, and some applications presented. Flow injection coulometric titrations are presented as a means to further alleviate reagent stability and calibration problems. These systems have potential for automatically carrying out many drug assays.

Calibration↗
PubMedDate not supplied

Miniaturized total analysis systems for biological analysis.

This review article discusses and documents the basic philosophies, concepts and current advances in the field of micro-TAS development, with special emphasis on applications in the arena of biosciences. After a brief overview of miniaturization theory and fabrication techniques, areas of microfluidic component development, detection protocols, biochemical assays, and integrated biological analyses are addressed.

Biochemical Phenomena↗
PubMed1994

Systems analysis of yeast glycolysis using perturbations of external pH: physiological parameters, non-parametric analysis, and general properties of the system dynamics.

A global systems analysis approach to yeast glycolysis is presented. Starting from a high flux steady state of anaerobic glycolysis rapid changes of external pH are applied. The dynamics of the transduction of the pH signal to the in vivo fluorescence of reduced pyridine nucleotides are investigated. Physiological studies indicate no significant influence of external pH on glycolytic flux and energy charge, but stationary concentrations of metabolites are increased after increasing the external pH from 5-7 particularly in the distal part of the glycolytic chain. Most of the changes in reduced pyridine fluorescence are due to glycolytically accessible NADH. As a first stage of system analytic investigations the premises for the approach were tested. The dynamic properties of the system are stable and the response is linear with respect to the input amplitude. The dynamic properties of the system depend on the state of adaptation to a certain external pH. The non-parametric model derived from single step experiments was used to correctly predict the response to pulses of variable duration. This indicates that the linear macroscopic approach to systems analysis with pH as input is applicable. The dynamics of the system response includes strongly damped oscillatory components. Their period lengths are similar to those found with temperature inputs and with the switching from low to high glycolytic flux under anaerobic conditions. This indicates that the three different signals may trigger common regulatory interactions. The order of the signal transduction process, indicating the number of basic processes involved, can be estimated to be 4 or higher.

Glycolysis↗
PubMed1992

[Progress on chromosome image analysis systems].

This is a review of the development of automated systems of chromosome analysis. The history of its development reflects the progress of image analysis systems and that of method of chromosome analysis in man. It can be chronologically summarized as follows. Period I: 1960s-early 1970s when chromosome banding methods were discovered. Period II: early 1970s-early 1980s when the first image analysis system of chromosome was commercialized. Period III: early 1980s-present. Research and development of the automated analysis system of radiation induced chromosome aberrations, conducted under the national project of cross-over research on underlying technology of nuclear energy, Science and Technology Agency, Japan, is briefly reported.

Chromosomes↗
PubMed1992

Role of visuo-vestibular interaction in pathological ocular oscillation: new model and control system analysis.

Control system engineering is a relatively newer field of engineering which is directly applicable to performance analysis of neuronal networks. Visuo-vestibular interaction (VVI) represents a neuronal control system which has most benefited from such analysis. In this paper, we present a new model of VVI derived from our previously reported model by adding cortical pursuit feedback. Mathematical analysis of abnormal eye oscillations and stability analysis of the VVI system provided us with a plausible hypothesis that the pathological ocular oscillations seen in oculopalatal myoclonus and see-saw nystagmus are indeed due to an unstable VVI control system. The former is due to degeneration of the inferior olivary nucleus resulting in loss of cerebellar learning effects, while the latter is due to disruption of the pathway conveying retinal error signals.

Animals↗
PubMed2005

Systems analysis of urban wastewater systems--two systematic approaches to analyse a complex system.

This work was aimed at performing an analysis of the integrated urban wastewater system (catchment area, sewer, WWTP, receiving water). It focused on analysing the substance fluxes going through the system to identify critical pathways of pollution, as well as assessing the effectiveness of energy consumption and operational/capital costs. Two different approaches were adopted in the study to analyse urban wastewater systems of diverse characteristics. In the first approach a wide ranged analysis of a system at river basin scale is applied. The Nete river basin in Belgium, a tributary of the Schelde, was analysed through the 29 sewer catchments constituting the basin. In the second approach a more detailed methodology was developed to separately analyse two urban wastewater systems situated within the Ruhr basin (Germany) on a river stretch scale. The paper mainly focuses on the description of the method applied. Only the most important results are presented. The main outcomes of these studies are: the identification of stressors on the receiving water bodies, an extensive benchmarking of wastewater systems, and the evidence of the scale dependency of results in such studies.

Belgium↗
PubMed1975

[The usefulness of system analysis to reduce the anaesthetic risk (author's transl)].

The attempt is made to increase the safety of anaestesia by the method of categorizing separate risk factors. It is very important to minimize these risk factors, but I do not think this is the way to do it. I propose to tackle this problem by the method of systems analysis. Systems analysis would also result in a certain levelling out of the demands made on both the staff and the equipment of an anesthesiology department and help to build a bridge between us and our industrial supplies. Systems analysis rejects the examination of separate risk factors in order to study the system as a whole and the functional cohesion of the various elements within it. In anesthesia, there are 3 different systems to be studied: the induction phase, the phase of true anesthesia, the recovery phase. The induction phase is discussed in this paper as an example of the thought processes and steps involved in a study by means of systems analysis.

Anesthesia↗
PubMedDate not supplied

Systems analysis of a clinical error.

Systems analysis is an approach used in situations requiring high reliability. In the past, the investigation and prevention of clinical error focused on the actions of individuals. A systems analysis approach to medical errors can identify and correct multiple contributing factors resulting in safer patient care systems. Recent analysis of a clinical error that occurred in public health practice identified multiple factors contributing to its occurrence. The use of the systems analysis approach resulted in high staff satisfaction and creative suggestions for operating a safer clinic and providing better patient care.

Community Health Centers↗
PubMed2002

Systems analysis of matrix metalloproteinase mRNA expression in skeletal tissues.

The availability of human genome sequences provides life scientists and biomedical engineers with a challenging opportunity to develop computational and experimental tools for quantitatively analyzing biological processes. In response to a growing need to integrate experimental mRNA expression data with human genome sequences, we present here a unique analysis named "Promoter-Based Estimation (PROBE)" analysis. The PROBE analysis is "systems analysis" of transcriptional processes using control and estimation theories. A linear model was built in order to estimate the mRNA levels of a group of genes from their regulatory DNA sequences. The model was also used to interpret two independent datasets in skeletal tissues. The results demonstrated that the mRNA levels of a family of matrix metalloproteinases can be modeled from a distribution of cis-acting elements on regulatory DNA sequences. The model accurately predicted a stimulatory role of cis-acting elements such as AP1, NFY, PEA3, and Sp1 as well as an inhibitory role of AP2. These predictions are consistent with biological observations, and a specific assay for testing such predictions is proposed. Although eukaryotic transcription is a complex mechanism, the two examples presented here support the potential use of the described analysis for elucidating the functional significance of DNA regulatory elements.

Algorithms↗
PubMed1989

Characterization of normal brain tissue using seven calculated MRI parameters and a statistical analysis system.

A statistical analysis system for classifying normal brain tissue has been applied to the analysis of MRI scans on 45 volunteers. The Bayes Maximum Likelihood method was used to achieve a discrimination accuracy of 84% for 13 tissue types among three age group sets, with classification accuracies for individual regions ranging from 50 to 100%. In order to attain this level of discrimination a set of seven derived relaxation-type parameters was used to categorize the tissue types. Values for these experimentally estimated parameters were derived from the MRI intensities of eight images in the following pulse sequences: (1) a Carr-Purcell-Meiboom-Gill (CPMG) four-echo train, (2) a single-echo inversion recovery, and (3) three single-echo sequences with varying repetition times, TR, and echo delays, TE. The T2 values derived from ratios of single-echo intensities showed better discrimination power than those from the four-echo CPMG train. The general precision of the seven estimated parameters was excellent, with percentage standard deviations ranging from 4 to 18% for the various regions studied. The tissue discrimination achieved by use of just three relaxation parameters, T1, T2, and proton density, calculated from intensities of images from a four-echo sequence, an inversion recovery sequence, and a short TR single-echo sequence, was not as good, being only 55%.

Adult↗
PubMed1996

Linear systems analysis of activating processes of complement system as a defense mechanism.

The complement system is an important element of the host defense mechanism, although its kinetics and characteristics as a system are still unclear. We have investigated its temporal changes and system properties from the view point of system engineering. The temporal changes of sequential activating processes of the system were expressed by 26 non-linear differential equations using reported values of rate constants and serum concentration for each component. The intermediate products in the activating processes increased parabolically while the membrane attack component as the final product, increased linearly. The little change in inactive precursors afforded validity for system linearization. Linear systems analysis revealed that the system which was insensitive to the changes in rate constants was unstable. The system became stable when the feed-back input from the final product was set to operate on the first step of the activating processes. Seven uncontrollable variables were insensitive to changes in rate constants or system optimization that minimized the changes in concentrations of components in the complement system. The singular values of the complement system were reduced and the impulse responses of the system were improved when the system was optimized. When stronger minimization was imposed on the changes of concentration of the components in the complement system, the singular values were reduced more, the magnitude of the impulse responses was depressed further and the responses terminated earlier than those when the elements in the weighting matrix of concentration of the components were set to be unity. By this potent minimization, the influences of changes in rate constants on the singular values were diminished. The present theoretical analysis is presented to evaluate the ability of defense mechanism of complement system.

Animals↗
PubMed1990

Electrocardiographic ambulatory monitoring with a real-time analysis system.

The analysis of records collected during long-term ambulatory electrocardiographic monitoring has traditionally involved the review of massive data, either manually or with the aid of interactive scanning computers. Many factors complicate this analysis, including the use of analog tape for storage of electrocardiographic waveforms, the need to analyze 100,000 waveforms from an average 24-hour study, and the need to deal with an interface that compresses 24 hours of data into as little as 6 minutes on a screen. Today, the computer incorporated in the monitor can scrutinize each cardiac cycle in real time. The system produces a statistical report based on every heart beat and also performs data reduction and storage of electrocardiograph samples. To assess real-time analysis we examined data collected from the Circadian CircaMed ambulatory electrocardiography system. We found that it could detect and quantify simple or complex ventricular ectopic beats, brady- or tachyarrhythmic events, and ST-segment deviation. One hundred fifty patients 21 to 85 years old with symptoms or clinical finding suggestive of ischemia, cardiac arrhythmia, or conductive defects were referred to our electrocardiography laboratory for ambulatory monitoring. The results demonstrate that this system can detect the full range of cardiac disease found with the traditional method. Of the 150 patients, ambulatory electrocardiographic tests were positive in 93 (62%). In addition, we developed a methodology for lead placement when using two bipolar leads, as is typical for ambulatory electrocardiography. We present a procedure for determining the optimum lead placement that is based on the patient's history and a 12-lead electrocardiogram.

Adult↗
PubMed1992

Comparison of the accuracy and reproducibility of the keratometer and the EyeSys Corneal Analysis System Model I.

The EyeSys Corneal Analysis System Model I measures corneal topography using digital image analysis of placido rings reflected off the cornea. With three observers, we compared the accuracy and reproducibility (precision) of the Marco Keratometer Model 1 and EyeSys Corneal Analysis System Model I using four poly(methyl methacrylate) spheres (37.50, 42.51, 47.54, and 55.06 diopters [D]), three steel spheres (40.50, 42.50, and 44.75 D), and 20 normal human eyes (41.50 to 46.00 D). For the spheres, the standard deviations of intra-observer and overall reproducibility for both devices were less than 0.12 D; the absolute mean differences between the measurements of the seven spheres and the known values were 0.25 D or more for two spheres as measured by the keratometer and none as measured by the EyeSys. For the normal corneas, the standard deviations of intra-observer and overall reproducibility for dioptric measurements were 0.07 D and 0.14 D for the keratometer and 0.13 D and 0.19 D for the EyeSys. The EyeSys Corneal Analysis System Model I exceeds keratometer accuracy in reading calibrated spheres and approaches keratometer reproducibility in measuring the 3-mm zone of normal human corneas.

Cornea↗
PubMed1995

Ergonomic analysis of working posture in nursing personnel: example of modified Ovako Working Analysis System application.

A postural analysis system was developed using a biomechanical approach to identify low back pain related working postures of nursing personnel. The Ovako Working Analysis System (OWAS) was modified for doing postural recording. Chaffin's biomechanical model was used to calculate the associated work stress on the L5/S1. The system was applied to examine the working postures of 64 nurses of 16 departments. The frequency distribution of the trunk showed 15.9% of the 8,629 observed postures were bending more than 15 degrees. Based on the calculated stress, 17.0% of the observed postures generated forces higher than the recommended action limit of the National Institute for Occupational Safety and Health (NIOSH). In addition to patient transfers, potentially health hazardous postures were identified in nursing tasks of inspection, nursing techniques, instrumentation, physical examination, taking inventory, and documentation.

Adult↗
PubMed1989

The Communication Analysis System.

The Communication Analysis System (CAS) was developed to facilitate efficient, effective treatment of conversational performance for persons with aphasia. The CAS provides frequent, objective, accurate, ratio-quality measures of ten classes of communicative behaviors for the patient and 11 for the clinician. The clinician using the CAS records the time of occurrence of communicative behaviors by a single keystroke on a keypad attached to an inexpensive microcomputer. The CAS software permits the analysis of data before the next clinical session and includes a method for assessing accuracy and reliability. Sample between-session data show the progress of one patient over several months, whereas within-session data illustrate a use of the CAS to measure a patient's performance under different communicative conditions. Simultaneously, measures of the clinician's communicative performance provide an accurate record of the treatment. This, in turn, allows observation of changes in the patient's behavior as a function of changes in the clinician's behavior. Clinical treatment can thereby be tailored precisely to the individual, optimizing the patient's rehabilitation.

Aged↗