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Results for “Systems Analysis”

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At least 667 records · Page 37Linked to original sources
PubMed1991

[The systems analysis of the central hemodynamics in parathyroprival hypocalcemia].

In experiments on cats under parathyroid hypocalcemia the reaction of cardiovascular system on adrenalin and physiological solution administration was investigated. It is shown that after removing the parathyroid glands, parathyroid hypocalcemia decreases the parameters of central hemodynamics. In this case, administration of adrenalin causes an extreme pressor effect due to vascular component of common hemodynamic reaction. Parathyroid deficiency decreases the cardial component in response to the action of physiological solution and adrenalin. The role of calcium-regulating hormonal system in the changes of central hemodynamics before and after physiological loads is discussed.

Animals↗
PubMed2004

Chloride-selective membrane electrodes and optodes based on an indium(III) porphyrin for the determination of chloride in a sequential injection analysis system.

Two quasi-independent methods for potentiometric and optical determination of chloride were simultaneously implemented in a flow system, providing real-time assessment of the quality of results. A potentiometric and an optical polymeric membrane doped with the same indium(III) octaethyl-porphyrin were used as sensor ionophore. The working mechanism and the analytical characteristics of these porphyrin-based sensors with respect to dynamic range, selectivity, repeatability and lifetime are discussed. These sensors, utilised as detectors in a flow system, were applied for the analysis of chloride in pharmaceutical solutions. The quality of the results obtained was evaluated by comparison with those provided by the reference method and no significant statistical differences at the 95% confidence level were observed. The simultaneous attainment of two measurements permitted the standardisation of results in real time and the detection of failures in the procedure.

Calibration↗
PubMed1989

Characterization of a computerized semen analysis system.

In the present studies we have evaluated the optimal operating conditions for the Hamilton-Thorn HTM-2000 computerized semen analyzer (Hamilton-Thorn, Danvers, MA). The best reproducibility in measurement of sperm concentration was obtained using 20 frames acquired at 19 frames/s. The measurement of sperm concentration was not adversely affected by the number of fields analyzed. The intrasample and intersample coefficients of variation for sperm concentration were 9.5% and 25.5%; sperm motility, 18.4% and 28.9%; lateral head displacement, 16.5% and 19.9%; path velocity, 6.8% and 13.9%; progressive velocity, 4.5% and 9.9%; and linear index, 2.5% and 4.2%; respectively. These differences suggest that sampling error has a significant influence on the reliability of sperm evaluation. The precision and rapidity of the HTM-2000 compares favorably with data previously reported from other systems available for clinical semen analysis.

Diagnosis, Computer-Assisted↗
PubMed2004

Micro wet analysis system using multi-phase laminar flows in three-dimensional microchannel network.

A three-dimensional microchannel network with two-level crossings of channels was constructed in a glass microchip by sandwiching an insulating glass plate between two glass plates with microchannels followed by thermal bonding. Pressure-driven stable multi-phase laminar flows inside the three-dimensional channel network were realized by balancing flow rates of syringe pumps. Micro unit operations for mixing, reaction, solvent extraction, and detection were properly arranged in the multi-phase laminar flows, so that four parallel analyses, comprising twenty unit operations in total, could be integrated onto a single chip. Two chelating reagents and two sample solutions containing heavy metal ions (Fe(ii) or Co(ii)) were mixed and reacted in four different combinations using the three-dimensional channel network. After chelating reactions were completed, post processing (solvent extraction or addition of acid) was applied to each solution stream to remove the interferences of coexisting metal ions. Finally, target metal complexes were detected using a thermal lens microscope (TLM). Integrity of the micro system was confirmed by qualitative analysis of Fe(ii) and Co(ii). This is the first example of continuous flow chemical processing utilizing multi-phase laminar flow realized in a three-dimensional channel network.

Glass↗
PubMed2006

Systems analysis of circadian time-dependent neuronal epidermal growth factor receptor signaling.

BACKGROUND: Identifying the gene regulatory networks governing physiological signal integration remains an important challenge in circadian biology. Epidermal growth factor receptor (EGFR) has been implicated in circadian function and is expressed in the suprachiasmatic nuclei (SCN), the core circadian pacemaker. The transcription networks downstream of EGFR in the SCN are unknown but, by analogy to other SCN inputs, we expect the response to EGFR activation to depend on circadian timing. RESULTS: We have undertaken a systems-level analysis of EGFR circadian time-dependent signaling in the SCN. We collected gene-expression profiles to study how the SCN response to EGFR activation depends on circadian timing. Mixed-model analysis of variance (ANOVA) was employed to identify genes with circadian time-dependent EGFR regulation. The expression data were integrated with transcription-factor binding predictions through gene group enrichment analyses to generate robust hypotheses about transcription-factors responsible for the circadian phase-dependent EGFR responses. CONCLUSION: The analysis results suggest that the transcriptional response to EGFR signaling in the SCN may be partly mediated by established transcription-factors regulated via EGFR transcription-factors (AP1, Ets1, C/EBP), transcription-factors involved in circadian clock entrainment (CREB), and by core clock transcription-factors (Ror alpha). Quantitative real-time PCR measurements of several transcription-factor expression levels support a model in which circadian time-dependent EGFR responses are partly achieved by circadian regulation of upstream signaling components. Our study suggests an important role for EGFR signaling in SCN function and provides an example for gaining physiological insights through systems-level analysis.

Animals↗
PubMed2001

BPR (business process redesign) and systems analysis and design: making the case for integration.

The question of what role business process redesign (BPR) should play in information systems development is one that draws strong opinions on either side of the issue. Some argue that BPR is absolutely necessary in forging a synergy between organizational structure, people, technology, and tasks. However, consultation and application development continue today without sufficient workflow analysis, as if BPR was irrelevant altogether. This article examines major BPR theories and the similarities and differences between BPR and information systems development and engages in a discussion of the merits of including BPR in any information systems development project.

Efficiency, Organizational↗
PubMed2006

Flow injection analysis system equipped with a newly designed electrochemiluminescent detector and its application for detection of 2-thiouracil.

A new flow injection analysis (FIA) system equipped with an electrochemiluminescent (ECL) detector has been developed and applied for the ECL detection of 2-thiouracil. The FIA-ECL system used a specially designed flow-through ECL thin-layer cell to reduce the dead volume, the IR drop across the cell, and the probability of accumulation of gas bubbles in the cell. It was thus envisioned to improve the detection limit of the FIA-ECL method. After being established, the new FIA-ECL system was used to investigate the ECL response of 2-thiouracil in the presence of the ECL of Ru(bpy)3(2+). It was found that 2-thiouracil could enhance the ECL of Ru(bpy)3(2+) over a wide pH range (pH 4.0-12.0). A highly sensitive method for detection of 2-thiouracil in biological samples was developed by the new FIA-ECL system after optimizing several experimental conditions, such as the applied potential of the working electrode, the pH value of the aqueous solution, the flow rate of carrier solution, and the concentration of Ru(bpy)3(2+).

Electrochemistry↗
PubMedDate not supplied

[Methodology for evaluation of disinfectants on the basis of system analysis].

The paper proposes a methodology based on the operation study theory, which can compare disinfectants by a combination of all their properties, which is integrated in the cost of tackling a disinfectological task rather than by the presence or magnitude of these or those useful properties.

Costs and Cost Analysis↗
PubMed2005

Denaturing high-performance liquid chromatography using the WAVE DNA fragment analysis system.

Denaturing high-performance liquid chromatography (DHPLC) is a chromatographic mutation analysis technique that is based on temperature-dependent separation of DNA containing mismatched base pairs from polymerase chain reaction (PCR)-amplified DNA fragments. The WAVE system, developed for DHPLC analysis, allows for unattended analysis of 96 samples directly from a PCR plate under a number of different conditions. It utilizes a Peltier cooling platform to maintain sample integrity. Sample detection is achieved via UV absorbance at 260 nm, thereby avoiding the cost, safety, variability, or waste disposal issues associated with radioisotopic, enzyme-linked, or fluorescence detection systems. There are four key aspects to successfully detecting mutations on the WAVE: (1) PCR primer design, (2) PCR protocol, (3) separation gradient, and (4) separation temperature. Provided these procedures are carried out correctly, almost 100% detection of single-nucleotide polymorphisms (SNPs) and small deletion/insertion mutations can be achieved. For this reason, DHPLC is a powerful tool for identifying mutations in candidate genes for hypertension.

Chromatography, High Pressure Liquid↗