PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Systems Analysis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 1,009 records · Page 56Linked to original sources
PubMed1985

Endarterectomy of the left coronary system. Analysis of a 10 year experience.

Between January, 1971, and June, 1981, 278 patients undergoing coronary artery bypass grafting had additional endarterectomy to the left coronary system. This constitutes 28% of all patients undergoing bypass grafting. Additional endarterectomy of the left anterior descending was performed in 250 and of the circumflex in 75 (an average of 1.2 endarterectomies to the left coronary system per patient). Five hundred thirty-six additional grafts to other vessels were performed, for a total of 861 grafts (three grafts per patient). There were 11 (4%) early and 29 (10%) late deaths. The actuarial survival rate was 93% at 3 years and 80% at 6 years. The incidence of perioperative myocardial infarction was 12%. Of the survivors, 94% were either asymptomatic or improved. Two hundred forty-three grafts (75%) were restudied early (2 weeks to 1 year). The early patency rate of the grafts to the left anterior descending was 83% (156/188) and to the circumflex 75% (41/55). In 75 patients (81 grafts), restudied 1 year or more after operation, the patency rate was 75% (61/81). The runoff of grafts to the left coronary system was judged to be good in 76%, moderate in 14%, and poor in 10%.

Adult↗
PubMed2000

Determination of depolymerization kinetics of amylose, amylopectin, and soluble starch by Aspergillus oryzae alpha-amylase using a fluorimetric 2-p-toluidinylnaphthalene-6-sulfonate/flow-injection analysis system.

This study reports on the determination of the depolymerization kinetics of amylose, amylopectin, and soluble starch by Aspergillus oryzae alpha-amylase using flow-injection analysis with fluorescence detection and 2-p-toluidinylnaphthalene-6-sulfonate as the fluorescent probe. The experimental data points, corresponding to the evolution of the concentration of "detectable" substrate with depolymerization time, were fit to a single exponential decay curve in the case of amylose and to a double exponential decay curve in the cases of amylopectin and soluble starch. For all the assayed substrates, the determined depolymerization rates at time zero correlated well with the initial enzyme and substrate concentrations through the usual Michaelis-Menten hyperbola. Therefore, this methodology allows the determination of alpha-amylase activity using any of these substrates. For amylopectin and soluble starch, the value of the total depolymerization rate at any depolymerization time was the result of the additive contribution of two partial depolymerization rates. In contrast, the total depolymerization rate for amylose was always a single value. These results, in conjunction with the relative time evolution of the two partial depolymerization rates (for amylopectin and soluble starch), are in good agreement with a linear molecular structure for amylose, a "grape-like" cluster molecular structure for amylopectin, and an extensively degraded grape-like cluster structure for soluble starch.

Amylopectin↗
PubMed2006

Comparison of five different abdominal access trocar systems: analysis of insertion force, removal force, and defect size.

Trocar designs have evolved in response to concerns about complication rates and surgical ergonomics. Functional properties of trocar systems that can be objectively measured include insertion force, removal force and the size of the tissue defect. This study will evaluate these properties in 5 common trocar designs. A porcine model was used to evaluate five different trocar systems for insertion force, removal force, and functional and measured tissue defect. Insertion force was lowest for cutting trocars and highest for radially dilating trocars. Removal force was similar for all trocars. Functional and measured tissue defect size was smallest for the hybrid type and radially dilating trocars. An ideal trocar system incorporates a low insertion force, secure retention, and a minimal tissue defect. Of the systems we tested, the hybrid type trocar has similar wound characteristics to the radially dilating trocar with the benefit of reduced insertion force. Further study is required to determine if these properties translate to an actual improvement in patient outcome.

Abdomen↗
PubMed1987

Cuba and the Philippines: contrasting cases in world-system analysis.

Cuba and the Philippines are countries with broad similarities in historical background yet sharp divergences in political economic developments and relations to the capitalist world-system in recent times. U.S. economic and political interests dominated both countries during the first half of the 20th century. The changes generated by the Cuban revolution resulted in the end of U.S. power in Cuba in 1959. The Philippines, however, remain profoundly dependent on the United States. The approach taken in this article contrasts these countries, asking what the results of their divergent paths are in terms of health and health services. The ability of Cuba and the Philippines to support the primary health care (PHC) approach by fostering socioeconomic justice, authentic citizen participation, and a regionalized health system is examined. It is clear that the last 25 years of socialist-oriented development in Cuba reversed the negative effects of the previous market economy by providing improved social and health services. The success of the political economy and the fully regionalized health system, supportive of the PHC approach in Cuba, is reflected in the high-level health status of the people. In contrast, poverty, gross social and economic inequities, high prevalence of infectious disease, and inaccessible, inadequate, and uncoordinated health services persist in the Philippines after some 85 years of international and national capitalist development. The poor health status of the Philippine people is a direct reflection of this underdeveloped system.

Community Participation↗
PubMed2003

Electrokinetic parameters of colloidal model systems: analysis and comparison between dilute and concentrated dispersions.

In the last decades, the interest of many scientists has been focused on the atypical electrokinetic behavior of charged colloidal systems since several studies have shown, in most cases; it is not so ideal as expected. Particularly, two interesting phenomena have not been clearly explained yet. First, the zeta potential magnitude does not decrease monotonically with increasing ionic strength, as expected according to the Gouy-Chapmann model predicts. Second, the zeta potential obtained from different techniques shows discrepancies. More specifically, the zeta potential obtained from streaming potential is lower (in absolute value) than that measured through electrophoretic mobility. However, a recent work has pointed out that these discrepancies seem to disappear if certain conditions (related with the surface charge density) are satisfied. This work also revealed that unexpected results are found when the electric conductivity was used. Spherical polystyrene particles of appropriate particle size and charge density are employed as polymeric colloidal model in the present work. Common and adequate models are used to make clear and easy our theoretical analysis and its interpretation. To test the surface conductance and ionic mobility effects at the solid-liquid interface, both water medium and alcohol-water mixtures are used.

Journal Article↗
PubMed2002

Systems analysis of Ran transport.

The separate components of nucleocytoplasmic transport have been well characterized, including the key regulatory role of Ran, a guanine nucleotide triphosphatase. However, the overall system behavior in intact cells is difficult to analyze because the dynamics of these components are interdependent. We used a combined experimental and computational approach to study Ran transport in vivo. The resulting model provides the first quantitative picture of Ran flux between the nuclear and cytoplasmic compartments in eukaryotic cells. The model predicts that the Ran exchange factor RCC1, and not the flux capacity of the nuclear pore complex (NPC), is the crucial regulator of steady-state flux across the NPC. Moreover, it provides the first estimate of the total in vivo flux (520 molecules per NPC per second and predicts that the transport system is robust.

Active Transport, Cell Nucleus↗
PubMed2004

CyDAS: a cytogenetic data analysis system.

For statistical analyses in cancer cytogenetics, the genomic changes encoded by the karyotype must be translated into numerical codes. We developed a program, which extracts chromosomal gains and losses as well as breakpoints from the karyotype. The changes are compiled in tables according to the chromosome bands involved and/or depicted in projection to the respective chromosome ideogram. The data are ready to be integrated into further statistical analyses. The program may be run as desktop or Internet application.

Chromosome Aberrations↗
PubMed2005

Systemic analysis and zygosity determination of the RHD gene in a D-negative Chinese Han population reveals a novel D-negative RHD gene.

BACKGROUND AND OBJECTIVES: The aim of this study was to systemically analyse the genetic background of D negativity in a Chinese Han population. MATERIALS AND METHODS: DNA of 74 D-negative samples was analysed by using an RHD multiplex polymerase chain reaction (MPX PCR) for the presence of RHD and by PCR-restriction fragment length polymorphism (PCR-RFLP) for RHD zygosity determination. Sixty-five samples were additionally analysed by using real-time quantitative PCR on RHD exon 7. RHD exon-specific sequencing was performed on discrepant samples. RESULTS: Forty-six samples (62%) showed the absence of RHD-specific exons by RHD MPX PCR and homozygous RHD negativity by PCR-RFLP. Twenty-two samples (30%) showed a 1227G>A mutation, characteristic for the Del phenotype. Five (7%) samples showed all characteristics of the RHD(1-2)-CE(3-9)-D(10) hybrid gene. One sample (1.4%) showed a novel 933C>A nonsense mutation in RHD exon 6, which resulted in a premature stop codon. CONCLUSIONS: The RHD gene deletion, RHD-CE-D hybrid genes and one novel 93C>A mutation were found to be the three mechanisms that cause D negativity in our samples. The 1227G>A Del mutation was found to be the major cause of discrepant results between genotyping and phenotyping strategies, favouring genotyping of D-negative samples.

China↗
PubMed1996

A two-hybrid system analysis shows interactions between 6-phosphofructo-1-kinase and 6-phosphofructo-2-kinase but not between other glycolytic enzymes of the yeast Saccharomyces cerevisiae.

The yeast two-hybrid system was used to investigate whether protein-protein interactions between enzymes of the early reactions of glycolysis exist in the yeast Saccharomyces cerevisiae. Various glycolytic enzymes were fused either to the GAL4 transcription-activating or DNA-binding domain and were tested for their ability to restore GAL4-dependent gene activation. All the different fusion proteins complemented the growth and enzymatic defects caused by the deletion of the respective genes, which indicates that these proteins are still functional. Interactions between the two phosphofructo-1-kinase subunits PFK1 and PFK2, interactions between the phosphofructo-2-kinase subunits, and dimerization of phosphoglucose isomerase were demonstrated. Dimerization of hexokinase 2, however, could not be demonstrated neither with N-terminal nor C-terminal fusions. A direct interaction between the hexose-6-phosphate interconverting enzymes hexokinase 2, phosphoglucose isomerase, and phosphofructo-1-kinase could also not be demonstrated. Nevertheless, our results indicate a weak interaction between phosphofructo-1-kinase and phosphofructo-2-kinase.

Base Sequence↗
PubMed1995

[Neurosarcoidosis of the central nervous system. Analysis of the long-term follow-up of 8 cases].

We present retrospective and follow-up data of eight patients with sarcoidosis involving the central nervous system (CNS). The diagnosis was established definitely by histological evidence in seven cases. Biopsies were taken directly from the CNS or the covering meninges in two of them. Additionally, we included a further case with the characteristic triad of arthralgia, erythema nodosum and pulmonary hilar adenopathy on X-ray, representing Löfgren's syndrome. Systemic manifestation of sarcoidosis was hardly recognized in some cases and sometimes became evident only in the long term after recurring manifestations. The symptomatology in our cases can be summarized as follows: Mostly, meningopolyneuritic and meningoencephalopathic syndromes occurred, with, in addition, one case of chronic meningitis and two cases of spinal involvement. In two cases, CNS symptoms represented the initial manifestation of the disease. Furthermore, the stringent interdependency of non-neurologic and neurologic episodes of the disease was not recognized easily. Under these circumstances, the histological confirmation was often difficult. Thus, the latency between the first neurological signs of the disease and the diagnosis of neurosarcoidosis may be long, as in our cases (mean 27 months). The course of the disease was followed for a mean 8.1 (range 1-15) years. Seven patients showed at least partial recovery from progressive disease after corticosteroid therapy. One patient developed, subacutely, a fatal pontine-medullary syndrome. The potentially poor prognosis emphasizes the importance of diagnostic efforts.

Adrenal Cortex Hormones↗
PubMed2004

Automatic control of the extra-corporal bypass: system analysis, modelling and evaluation of different control modes.

Automatic control of the blood gas parameters during extracorporeal circulation has the potential to improve the quality of this procedure and to relieve the personnel from a time consuming task. This paper describes a model of the underlying system for a standard clinical set-up and pinpoints the major difficulties which are the variations of the process gains and the blood- and gas-flow dependent dead times and time constants. Scheduled PI-controllers both for the arterial oxygen as well as for the carbon dioxide partial pressure were designed. Scheduling was based on the blood flow rate. These controllers were tested in a simulation environment. The control systems remained stable under all tested operating condition, but if the blood flow rate was changed abruptly rather large load errors occurred. The performance was improved markedly by adding a feed-forward control path which directly influences the actuating signals based on the actual blood flow rate and the hemoglobin contents, variables which are measured anyway. The major conclusion of this study is to use such direct feed-forward compensation even if more sophisticated control algorithms are used.

Algorithms↗
PubMed2001

In situ XAFS analysis system for high-pressure catalytic reactions and its application to CO2 hydrogenation over a Rh/Y-zeolite catalyst.

An in-situ XAFS cell was developed and used for the structural analysis of a Rh ion-exchanged zeolite catalyst during high-pressure hydrogenation of carbon dioxide. The in-situ cell enabled analyses of the catalyst structures that changed with the reaction atmosphere and elapsed time; the peak assigned to Rh-O scattering changed to that assigned to Rh-Rh scattering at 404 K during the pretreatment by hydrogen. After 30 min. of the carbon dioxide hydrogenation reaction, the peak intensity assigned to Rh-Rh scattering increased corresponding to the increase in the catalytic activity.

Journal Article↗
PubMed2004

The dromotropic pacemaker: system analysis and design considerations.

Patients suffering from chronotropic incompetence are generally treated with a rate-responsive pacemaker that stimulates the heart at a rate derived from a strain related sensor signal. The pacemaker concept described here uses a well-defined time interval in the electrogram as sensor parameter (AVCT: atrio-ventricular conduction time). AVCT is directly controlled by the autonomic nervous system. The design of the new algorithm was based on a thorough experimental analysis of AVCT subject to variations of the exercise rate and the pacing frequency. There it was demonstrated that AVCT is disturbed by the respiratory activity. The new rate-responsive algorithm which uses the internal model control principle explicitly takes into account the closed-loop nature of the underlying system. The major design objectives were: a) extended range of the individual heart rate, b) effective attenuation of the respiratory related disturbance and c) dynamic stability. Seven patients undergoing an incremental exercise test were paced with the new AVCT-based algorithm. When paced with this algorithm the paced heart rate was 126 +/- 12 min(-1) whereas the peak intrinsic heart rate was only 100 +/- 20 min(-1). The increase which was significant (26 +/- 13 min(-1); 15.53 min(-1)) clearly demonstrated the potential of this concept to restore chronotropic competence. A reanalysis of the experiments was undertaken in order to facilitate the individual parameterization in clinical practice. It could be demonstrated that a rather simple screening test is sufficient to gain the knowledge necessary for the individual parameterisation.

Algorithms↗
PubMedDate not supplied

Systems analysis of the neuroimmunological mechanisms of memory.

Experimental data on the role of immunomodulators in the mechanisms of neurological memory are presented and assessed from the point of view of functional systems theory. It is demonstrated that the immunomodulator interleukin-1 beta and the alpha-2-interferon fragment RITLY improve the processes of learning and reproduction of an active defensive habit. These substances were found to have effects on the productivity of behavior, on orientational-investigative reactions, and on vocalization in response to a conditioned signal. A positive correlation between intersignal activity and productivity is demonstrated as a reflection of the mechanisms of anticipatory reorganization of behavior during learning. However, interleukin has a selective action depending on the ethological conditions obtained during learning.

Adjuvants, Immunologic↗