Search PubMed⌕ Search

PubMed · 355243

Cardiovascular system simulation requirements.

Abstract

Circulatory system characteristics are considered with respect to specifying model design parameters for simulators and pulse duplicators. The requirements are investigated to determine what characteristics and parameters are important in design and construction. The specific design depends on the functions of the device to be investigated. The single most important quantity is the modeled proximal capacitance or compliance of the large vessels. More detailed study specifications require more detailed models.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

W M Swanson, R E Clark. 1977. Cardiovascular system simulation requirements.. https://pubmed.ncbi.nlm.nih.gov/355243/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

C-reactive protein (CRP), a comparison of pre- and post-mortem blood levels.

During autopsy of 26 inpatients with elevated CRP levels (14-536 mg/l) blood was taken from the femoral vessels and analysed for the content of CRP. The post-mortem CRP values were compared with the results of CRP analysis performed within the last 24h before death. This showed that the post-mortem values of CRP in average were reduced with 35% compared to the ante-mortem values. The decrease in CRP levels was not significantly influenced by the time interval from death until blood was drawn for analysis, at least up to 6 days. When blood taken from healthy individuals killed in accidents was analysed, no elevated CRP values were observed, indicating that there is negligible risk for false positive results. It is also shown that frozen blood can be used for CRP analysis if an immunometric kit assay based on whole blood is applied. The results demonstrate that an elevated level of CRP in post-mortem blood is a good marker for an ongoing inflammatory process prior to death. CRP analysis may therefore be a helpful tool in post-mortem examinations, especially in non-hospitalised individuals without medical records.

Blood↗

Incorporation of oxyethylene units between hydrocarbon chain and pseudoglyceryl backbone in cationic lipid potentiates gene transfection efficiency in the presence of serum.

Four novel cationic lipids with different numbers of oxyethylene units at the linkage region between the pseudoglyceryl backbone and the hydrocarbon chains have been synthesized and used as mixtures with 1,2-dioleoyl-L-alpha-glycero-3-phosphatidyl ethanolamine (DOPE) for liposome-mediated gene transfection. Incorporation of different numbers of oxyethylene (-CH(2)CH(2)O-) units between long hydrocarbon chain at the C-1 and C-2 positions of the pseudoglyceryl skeleton improved the transfection efficiency considerably compared to the one in which the chains were connected via simple ether links. A pronounced improvement in the gene transfer efficiency was observed with the unsymmetrical cationic lipid 3 in which the long hydrocarbon at the C-1 position of the pseudoglyceryl segment is connected via two (-CH(2)CH(2)O-) units. Notably, the transfection ability of lipid 3 with DOPE in the presence of serum was significantly greater than LIPOFECTAMINE. This suggests that introduction of oxyethylene units between long hydrocarbon chains at the C-1 and C-2 positions of the pseudoglyceryl skeleton provides a novel strategy to achieve efficient gene transfer, especially in conditions where the presence of serum is critical.

Blood↗

Errors in the estimation of the distance of fall and angles of impact blood drops.

This paper presents derived equations for the estimation of the variances in the estimated distance of fall and the estimated angle of impact for blood droplets. The derived equation for the variance of the estimated distance of fall predicts that as the blood drop size approaches that of a blood droplet falling at terminal velocity, the variance of the estimate grows without limit. The derived equation for the variance in the estimated angle of impact shows that as the angle of impact approaches 90 degrees, the variance grows without limit. The validity of the equation for the estimated variance of the angle of impact was tested for five angles of impact (15, 30, 45, 60 and 75 degrees); the equation correctly predicted the observed variance up to an angle of 60 degrees.

Blood↗