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  1. Simulations of time harmonic blood flow in the Mesenteric artery: comparing finite element and lattice Boltzmann methods

    Directory of Open Access Journals (Sweden)

    Hose Rod

    2009-10-01

    Full Text Available Abstract Background Systolic blood flow has been simulated in the abdominal aorta and the superior mesenteric artery. The simulations were carried out using two different computational hemodynamic methods: the finite element method to solve the Navier Stokes equations and the lattice Boltzmann method. Results We have validated the lattice Boltzmann method for systolic flows by comparing the velocity and pressure profiles of simulated blood flow between methods. We have also analyzed flow-specific characteristics such as the formation of a vortex at curvatures and traces of flow. Conclusion The lattice Boltzmann Method is as accurate as a Navier Stokes solver for computing complex blood flows. As such it is a good alternative for computational hemodynamics, certainly in situation where coupling to other models is required.

  2. Finite volume numerical solution to a blood flow problem in human artery

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    Wijayanti Budiawan, Inge; Mungkasi, Sudi

    2017-01-01

    In this paper, we solve a one dimensional blood flow model in human artery. This model is of a non-linear hyperbolic partial differential equation system which can generate either continuous or discontinuous solution. We use the Lax–Friedrichs finite volume method to solve this model. Particularly, we investigate how a pulse propagates in human artery. For this simulation, we give a single sine wave with a small time period as an impluse input on the left boundary. The finite volume method is successful in simulating how the pulse propagates in the artery. It detects the positions of the pulse for the whole time period.

  3. A finite element study of balloon expandable stent for plaque and arterial wall vulnerability assessment

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    Karimi, Alireza; Navidbakhsh, Mahdi; Razaghi, Reza

    2014-07-01

    The stresses induced within plaque tissues and arterial layers during stent expansion inside an atherosclerotic artery can be exceeded from the yield stresses of those tissues and, consequently, lead to plaque or arterial layer rupture. The distribution and magnitude of the stresses in each component involved in stenting might be clearly different for different plaque types and different arterial layers. In this study, a nonlinear finite element simulation was employed to investigate the effect of plaque composition (calcified, cellular, and hypocellular) on the stresses induced in the arterial layers (intima, media, and adventitia) during implantation of a balloon expandable coronary stent into a stenosed artery. The atherosclerotic artery was assumed to consist of a plaque and normal/healthy arterial tissues on its outer side. The results indicated a significant influence of plaque types on the maximum stresses induced within the plaque wall and arterial layers during stenting but not when computing maximum stress on the stent. The stress on the stiffest calcified plaque wall was in the fracture level (2.38 MPa), whereas cellular and hypocellular plaques remain stable owing to less stress on their walls. Regardless of plaque types, the highest von Mises stresses were observed on the stiffest intima layer, whereas the lowest stresses were seen to be located in less stiff media layer. The computed stresses on the intima layer were found to be high enough to initiate a rupture in this stiff layer. These findings suggest a higher risk of arterial vascular injury for the intima layer, while a lower risk of arterial injury for the media and adventitia layers.

  4. Arterial elasticity imaging: comparison of finite-element analysis models with high-resolution ultrasound speckle tracking

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    Park Dae

    2010-06-01

    Full Text Available Abstract Background The nonlinear mechanical properties of internal organs and tissues may be measured with unparalleled precision using ultrasound imaging with phase-sensitive speckle tracking. The many potential applications of this important noninvasive diagnostic approach include measurement of arterial stiffness, which is associated with numerous major disease processes. The accuracy of previous ultrasound measurements of arterial stiffness and vascular elasticity has been limited by the relatively low strain of nonlinear structures under normal physiologic pressure and the measurement assumption that the effect of the surrounding tissue modulus might be ignored in both physiologic and pressure equalized conditions. Methods This study performed high-resolution ultrasound imaging of the brachial artery in a healthy adult subject under normal physiologic pressure and the use of external pressure (pressure equalization to increase strain. These ultrasound results were compared to measurements of arterial strain as determined by finite-element analysis models with and without a surrounding tissue, which was represented by homogenous material with fixed elastic modulus. Results Use of the pressure equalization technique during imaging resulted in average strain values of 26% and 18% at the top and sides, respectively, compared to 5% and 2%, at the top and sides, respectively, under physiologic pressure. In the artery model that included surrounding tissue, strain was 19% and 16% under pressure equalization versus 9% and 13% at the top and sides, respectively, under physiologic pressure. The model without surrounding tissue had slightly higher levels of strain under physiologic pressure compared to the other model, but the resulting strain values under pressure equalization were > 60% and did not correspond to experimental values. Conclusions Since pressure equalization may increase the dynamic range of strain imaging, the effect of the

  5. Finite element formulation and analysis for an arterial wall with residual and active stresses.

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    Kida, Naoki; Adachi, Taiji

    2015-08-01

    In this study, for predicting arterial function and pathogenesis from a mechanical viewpoint, we develop a continuum mechanical model of an arterial wall that embodies residual and active stresses following a traditional anisotropic passive constitutive law. The residual and active stresses are incorporated into finite element methods based on a two-field variational principle described in the Lagrangian form. The linearisation of nonlinear weak-form equations derived from this variational principle is then described for developing an original finite element algorithm. Numerical simulations reveal the following: (i) residual stresses lead to a reduction in stress gradient regardless of the magnitude of external load; (ii) active stresses help homogenise stress distribution under physiological external load, but this homogeneity collapses under pathological external load; (iii) when residual and active stresses act together, the effect of the residual stresses is relatively obscured by that of the active stresses. We conclude that residual stresses have minor but persistent mechanical effects on the arterial wall under both physiological and pathological external loads; active stresses play an important role in the physiological functions and pathogenesis of arteries, and the mechanical effect of residual stresses is dependent on the presence/absence of active stresses.

  6. Thermal buckling comparative analysis using Different FE (Finite Element) tools

    Energy Technology Data Exchange (ETDEWEB)

    Banasiak, Waldemar; Labouriau, Pedro [INTECSEA do Brasil, Rio de Janeiro, RJ (Brazil); Burnett, Christopher [INTECSEA UK, Surrey (United Kingdom); Falepin, Hendrik [Fugro Engineers SA/NV, Brussels (Belgium)

    2009-12-19

    High operational temperature and pressure in offshore pipelines may lead to unexpected lateral movements, sometimes call lateral buckling, which can have serious consequences for the integrity of the pipeline. The phenomenon of lateral buckling in offshore pipelines needs to be analysed in the design phase using FEM. The analysis should take into account many parameters, including operational temperature and pressure, fluid characteristic, seabed profile, soil parameters, coatings of the pipe, free spans etc. The buckling initiation force is sensitive to small changes of any initial geometric out-of-straightness, thus the modeling of the as-laid state of the pipeline is an important part of the design process. Recently some dedicated finite elements programs have been created making modeling of the offshore environment more convenient that has been the case with the use of general purpose finite element software. The present paper aims to compare thermal buckling analysis of sub sea pipeline performed using different finite elements tools, i.e. general purpose programs (ANSYS, ABAQUS) and dedicated software (SAGE Profile 3D) for a single pipeline resting on an the seabed. The analyses considered the pipeline resting on a flat seabed with a small levels of out-of straightness initiating the lateral buckling. The results show the quite good agreement of results of buckling in elastic range and in the conclusions next comparative analyses with sensitivity cases are recommended. (author)

  7. Effects of Crimping on Mechanical Performance of Nitinol Stent Designed for Femoral Artery: Finite Element Analysis

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    Nematzadeh, F.; Sadrnezhaad, S. K.

    2013-11-01

    Nitinol stents are used to minimize improper dynamic behavior, low twistability, and inadequate radial mechanical strength of femoral artery stents. In this study, finite element method is used to investigate the effect of crimping and Austenite finish temperature ( A f) of Nitinol on mechanical performance of Z-shaped open-cell femoral stent under crimping conditions. Results show that low A f Nitinol has better mechanical and clinical performance due to small chronic outward force, large radial resistive force, and appropriate superelastic behavior.

  8. Prediction of coronary plaque location on arteries having myocardial bridge, using finite element models.

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    Nikolić, Dalibor; Radović, Miloš; Aleksandrić, Srđan; Tomašević, Miloje; Filipović, Nenad

    2014-11-01

    This study was performed to evaluate the influences of the myocardial bridges on the plaque initializations and progression in the coronary arteries. The wall structure is changed due to the plaque presence, which could be the reason for multiple heart malfunctions. Using simplified parametric finite element model (FE model) of the coronary artery having myocardial bridge and analyzing different mechanical parameters from blood circulation through the artery (wall shear stress, oscillatory shear index, residence time), we investigated the prediction of "the best" position for plaque progression. We chose six patients from the angiography records and used data from DICOM images to generate FE models with our software tools for FE preprocessing, solving and post-processing. We found a good correlation between real positions of the plaque and the ones that we predicted to develop at the proximal part of the myocardial bridges with wall shear stress, oscillatory shear index and residence time. This computer model could be additional predictive tool for everyday clinical examination of the patient with myocardial bridge.

  9. A comparative study of finite element and finite difference methods for Cauchy-Riemann type equations

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    Fix, G. J.; Rose, M. E.

    1983-01-01

    A least squares formulation of the system divu = rho, curlu = zeta is surveyed from the viewpoint of both finite element and finite difference methods. Closely related arguments are shown to establish convergence estimates.

  10. Application of finite element analysis for assessing biocompatibility of intra-arterial catheters and probes.

    Science.gov (United States)

    Bedingham, W; Neavin, T D

    1991-01-01

    A commercial finite element modeling program (FIDAP) was adapted to compute the fluid dynamics of laminar blood flow around an intra-arterial catheter and/or sensor probe. The model provided an accurate transient solution to the Navier-Stokes equations under pulsatile blood flow conditions. To simulate the compliance in the catheter tubing set, a second order convolution integral was incorporated into the boundary conditions. The saline drip rate and catheter compliance could be specified, and the bulk blood flow, blood pressure, and heart rate were varied to simulate specific patient conditions. Analysis of the transient solution was used to assess probable sites for thrombus activation and deposition. The transient velocity and pressure fields identified regions of separated flow and recirculation. The computed shear rates and stresses were used to predict hemolysis, platelet activation, and thrombus formation. Analysis of particle paths provided an estimate of residence times and thrombus deposition sites.

  11. COMPARATIVE MORPHOFUNCTIONAL CHARACTERISTIC OF ADRENAL GLANDS IN ARTERIAL HYPERTENSION

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    S. Yu. Alyabyeva

    2015-01-01

    Full Text Available The article is devoted to the study of morphological changes of the adrenal glands in arterial hyperten-sion. Adrenals investigated persons who do not suffer in life and suffering from hypertension during the life of hypertension and died from various causes – is incompatible with the life of a mechanical trauma, cerebral hemorrhage, and acute left ventricular failure. In each case, each of the adrenal glands were assessed: the presence and severity of focal and diffuse mononuclear infiltration, the number of lympho-cytes, monocytes, plasma cells and fibroblasts arranged in the respective zones of the cortex and medulla, the severity of hyperemia and edema of various structural parts, the number of zones cortex and medulla endocrinocytes with pycnotic nuclei in the reticular zone evaluated the distribution of secretory cells with lipofuscin and the degree of saturation of the cytoplasm of the secretory cells, in secretory cells of medul-la evaluated nuclear-cytoplasmic ratio, the severity of vacuolization and basophils cytoplasm revealed a number of regularities of morphological changes depending from the various clinical manifestations of hypertension, defining the ultimate option of dying. At the heart tanatogenesis version are more pro-nounced morphological features hyperfunctions glomerular zone – namely delipidization left and right glands. The beam and netted areas contralateral glands embodiment of dying of a heart compared to the brain, is more pronounced hyperemia. When cardiac variant tanatogenesis more pronounced focal lym-phoid infiltration and vacuolization in secretory cells of left adrenal medulla.

  12. FINITE ELEMENT GALERKIN APPROACH FOR A COMPUTATIONAL STUDY OF ARTERIAL FLOW

    Institute of Scientific and Technical Information of China (English)

    G.C.Sharma(G.C.夏玛); Madhu Jain(马德胡·珍); Anil Kumar(阿尼尔·克乌玛)

    2001-01-01

    A finite element solution for the Navier-Stokes equations for steady flow through a double branched two dimensional section of three dimensional model of canine aorta is obtained. The numerical technique involves transformation of the physical coordinates to a curvilinear boundary fitted coordinate system. The shear stress at the wall is calculated for Reynolds number of 1000 with branch to main aortic flow rate ratio as a parameter. The results are compared with earlier works involving experimental data and it is observed that the results are very close to their solutions. This work in fact is an improvement of the work of Sharma and Kapoor (1995) in the sense that computations scheme is economic and Reynolds number is large.

  13. Discrepant ratios of arterial versus venous thrombosis in hemophilia A as compared with hemophilia B.

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    Girolami, Antonio; Bertozzi, Irene; de Marinis, Giulia Berti; Tasinato, Valentina; Sambado, Luisa

    2014-04-01

    The occurrence of thrombosis in patients with congenital bleeding disorders represents an exceptional event. Hemophilia A and hemophilia B patients have been showed to present both arterial and venous thrombosis (85 cases of arterial thrombosis and 34 cases of venous thrombosis). The great majority of arterial thrombosis are myocardial infarction or other acute coronary syndromes, whereas the majority of venous thrombosis are deep vein thrombosis and/or pulmonary embolisms. However there are discrepancies in the proportion of arterial and venous thrombosis seen in hemophilia A versus hemophilia B. The ratio of arterial versus venous thrombosis in hemophilia A is 3.72 whereas that for hemophilia B is 1.12. This indicates that arterial thrombosis is more frequent in hemophilia A as compared to hemophilia B and the opposite is true for venous thrombosis. The potential significance of this discrepancy is discussed.

  14. Finite element analyses for design evaluation of biodegradable magnesium alloy stents in arterial vessels

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    Wu Wei [Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan (Italy); Gastaldi, Dario, E-mail: dario.gastaldi@polimi.it [Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan (Italy); Yang Ke; Tan Lili [Division of Specialized Materials and Devices, Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China); Petrini, Lorenza; Migliavacca, Francesco [Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan (Italy)

    2011-12-15

    Biodegradable magnesium alloy stents (MAS) can provide a great benefit for diseased vessels and avoid the long-term incompatible interactions between vessels and permanent stent platforms. However, the existing MAS showed insufficient scaffolding to the target vessels due to short degradation time. In this study, a three dimensional finite element model combined with a degradable material model of AZ31 (Al 0.03, Zn 0.01, Mn 0.002 and Mg balance, mass percentage) was applied to three different MAS designs including an already implanted stent (Stent A), an optimized design (Stent B) and a patented stent design (Stent C). One ring of each design was implanted through a simulation in a vessel model then degraded with the changing interaction between outer stent surface and the vessel. Results showed that a proper stent design (Stent B) can lead to an increase of nearly 120% in half normalized recoil time of the vessel compared to the Stent A; moreover, the expectation that the MAS design, with more mass and optimized mechanical properties, can increase scaffolding time was verified numerically. The Stent C has more materials than Stent B; however, it only increased the half normalized recoil time of the vessel by nearly 50% compared to the Stent A because of much higher stress concentration than that of Stent B. The 3D model can provide a convenient design and testing tool for novel magnesium alloy stents.

  15. Nitinol Stent Oversizing in Patients Undergoing Popliteal Artery Revascularization: A Finite Element Study.

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    Gökgöl, Can; Diehm, Nicolas; Nezami, Farhad Rikhtegar; Büchler, Philippe

    2015-12-01

    Nitinol stent oversizing is frequently performed in peripheral arteries to ensure a desirable lumen gain. However, the clinical effect of mis-sizing remains controversial. The goal of this study was to provide a better understanding of the structural and hemodynamic effects of Nitinol stent oversizing. Five patient-specific numerical models of non-calcified popliteal arteries were developed to simulate the deployment of Nitinol stents with oversizing ratios ranging from 1.1 to 1.8. In addition to arterial biomechanics, computational fluid dynamics methods were adopted to simulate the physiological blood flow inside the stented arteries. Results showed that stent oversizing led to a limited increase in the acute lumen gain, albeit at the cost of a significant increase in arterial wall stresses. Furthermore, localized areas affected by low Wall Shear Stress increased with higher oversizing ratios. Stents were also negatively impacted by the procedure as their fatigue safety factors gradually decreased with oversizing. These adverse effects to both the artery walls and stents may create circumstances for restenosis. Although the ideal oversizing ratio is stent-specific, this study showed that Nitinol stent oversizing has a very small impact on the immediate lumen gain, which contradicts the clinical motivations of the procedure.

  16. Mechanical Interaction of an Expanding Coiled Stent with a Plaque-Containing Arterial Wall: A Finite Element Analysis.

    Science.gov (United States)

    Welch, Tré R; Eberhart, Robert C; Banerjee, Subhash; Chuong, Cheng-Jen

    2016-03-01

    Wall injury is observed during stent expansion within atherosclerotic arteries, related in part to stimulation of the inflammatory process. Wall stress and strain induced by stent expansion can be closely examined by finite element analysis (FEA), thus shedding light on procedure-induced sources of inflammation. The purpose of this work was to use FEA to examine the interaction of a coiled polymer stent with a plaque-containing arterial wall during stent expansion. An asymmetric fibrotic plaque-containing arterial wall model was created from intravascular ultrasound (IVUS) images of a diseased artery. A 3D model for a coil stent at unexpanded state was generated in SolidWorks. They were imported into ANSYS for FEA of combined stent expansion and fibrotic plaque-distortion. We simulated the stent expansion in the plaqued lumen by increasing balloon pressure from 0 to 12 atm in 1 atm step. At increasing pressure, we examined how the expanding stent exerts forces on the fibrotic plaque and vascular wall components, and how the latter collectively resist and balance the expansive forces from the stent. Results show the expanding coiled stent creates high stresses within the plaque and the surrounding fibrotic capsule. Lower stresses were observed in adjacent medial and adventitial layers. High principal strains were observed in plaque and fibrotic capsule. The results suggest fibrotic capsule rupture might occur at localized regions. The FEA/IVUS method can be adapted for routine examination of the effects of the expansion of selected furled stents against IVUS-reconstructed diseased vessels, to improve stent deployment practices.

  17. Quantification of blood flow velocity in stenosed arteries by the use of finite elements: an observer-independent noninvasive method.

    Science.gov (United States)

    Mühlthaler, Hannes; Quatember, Bernhard; Fraedrich, Gustav; Mühlthaler, Markus; Pfeifer, Bernhard; Greiner, Andreas; Schocke, Michael F H

    2008-10-01

    Interventions for peripheral arterial disease should be designed to treat a physiological rather than an anatomic defect. Thus, for vascular surgeons, functional information about stenoses is as important as the anatomic one. In case of finding a stenosis by the use of magnetic resonance angiography, it would be a matter of particular interest to derive automatically and directly objective information about the hemodynamic influence on blood flow, caused by patient-specific stenoses. We developed a methodology to noninvasively perform numerical simulations of a patient's hemodynamic state on the basis of magnetic resonance images and by the means of the finite element method. We performed patient-specific three-dimensional simulation studies of the increase in systolic blood flow velocity due to stenoses using the commercial computational fluid dynamic software package FIDAP 8.52. The generation of a mesh defining the flow domain with a stenosis and some simulation results are shown.

  18. Comparably improved health-related quality of life after total arterial revascularization versus conventional coronary surgery--Copenhagen arterial revascularization randomized patency and outcome trial

    DEFF Research Database (Denmark)

    Damgaard, Sune; Lund, Jens T; Lilleør, Nikolaj B

    2011-01-01

    OBJECTIVE: We compared health-related quality of life up to 11 months after coronary artery bypass grafting using total arterial revascularization versus conventional coronary surgery. METHODS: In this randomized single-center trial, 161 patients underwent total arterial revascularization using.......01). For total arterial revascularization, there were also not statistically significant improvements for 'physical component summary' (P=0.09), 'bodily pain' (P=0.07) and 'vitality' (P=0.08). CONCLUSION: Health-related quality of life up to 1 year after total arterial revascularization is equal or slightly...... of the general Danish population. On all scales of the SF-36, there was statistically significant improvement at 3 and 11 months in both groups. For 'social functioning', the improvement following total arterial revascularization was significantly higher than following conventional revascularization (P=0...

  19. Neurological Complications Comparing Endoscopically vs. Open Harvest of the Radial Artery

    Science.gov (United States)

    2016-07-05

    Complications Due to Coronary Artery Bypass Graft; Coronary Artery Disease; Myocardial Ischemia; Coronary Disease; Heart Diseases; Cardiovascular Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Vascular Diseases

  20. Age-related arterial telomere uncapping and senescence is greater in women compared with men.

    Science.gov (United States)

    Walker, Ashley E; Morgan, R Garrett; Ives, Stephen J; Cawthon, Richard M; Andtbacka, Robert H I; Noyes, Dirk; Lesniewski, Lisa A; Richardson, Russell S; Donato, Anthony J

    2016-01-01

    Telomere uncapping increases with advancing age in human arteries and this telomere uncapping is associated with increased markers of senescence, independent of mean telomere length. However, whether there are sex specific differences in arterial telomere uncapping is unknown. We found that telomere uncapping (serine 139 phosphorylated histone γ-H2A.X in telomeres) in arteries was ~2.5 fold greater in post-menopausal women (n=17, 63±2 years) compared with pre-menopausal women (n=11, 30±2 years, p=0.02), while there was only a trend towards greater telomere uncapping in older men (n=26, 66±2 years) compared with young men (n=11, 31±2, p=0.11). Senescence markers, p53 bound to the p21 gene promoter and p21 gene expression, were 3-4 fold greater in post-menopausal compared with pre-menopausal women (p=0.01-0.02), but only 1.5-2 fold greater in older compared with young men (p=0.02-0.08). Blood glucose was related to telomere uncapping in women, while systolic blood pressure, pulse pressure and serum creatinine were related to telomere uncapping in men. Mean arterial telomere length decreased similarly in women and men with age (ptelomere uncapping and senescence is greater in women than men, despite similar age-related reductions in mean telomere length in both sexes.

  1. Inflammatory response in patients undergoing uterine artery embolization as compared to patients undergoing conventional hysterectomy

    DEFF Research Database (Denmark)

    Brøchner, A C; Mygil, B; Elle, B;

    2009-01-01

    : To investigate whether uterine artery embolization generates a reduced inflammatory response as compared with conventional hysterectomy. MATERIAL AND METHODS: 40 women, 20 in each group, entered this prospective, non-randomized study. The two groups were comparable concerning age, comorbidity, and body......-mass index (BMI). RESULTS: We found a significant difference between the inflammatory responses in women undergoing embolization compared with the inflammatory response in women having an abdominal hysterectomy. Women undergoing embolization were subjected to a much smaller inflammatory burden, their total...... morphine consumption was lower, and their return to work was faster than women subjected to conventional hysterectomy. CONCLUSION: Uterine artery embolization generates a reduced inflammatory response compared with conventional hysterectomy....

  2. Pituitary dysfunction in survivors of spontaneous subarachnoid hemorrhage of anterior communicating artery and middle cerebral artery aneurysms: A comparative study

    Directory of Open Access Journals (Sweden)

    Pinaki Dutta

    2012-01-01

    Full Text Available Background: The data on incidence of hypopituitarism after SAH are conflicting. Furthermore, it is still not known whether there is any difference in hormonal deficiencies between SAH due to anterior communicating artery (A-com and middle cerebral artery (MCA aneurysms. Materials and Methods: This study includes both retrospective and prospective arms. The data collected included baseline demographic profile, clinical severity on admission to the hospital by the Hunt and Hess grading system and World Federation of Neurological Surgeons (WFNS grading, radiological severity of bleed by the Fisher′s classification, and treatment details. All the patients underwent detailed hormonal evaluation at baseline and 6 months in prospective group while at the end of 1 year in the retrospective group. Hormonal deficiencies between patients with A-com and MCA aneurysmal SAH were compared using appropriate statistical tests. Results: Of 60 patients studied, 47 patients (A-com: 28 and MCA: 19 were in the retrospective group, while 13 patients (A-com-9, MCA-4 were in the prospective group. The baseline data were comparable between the two groups. At or after 6 months follow-up, 19 (31.6% patients, 10 patients with A-com and 9 patients with MCA aneurysmal SAH, had some form of hormone deficiency. Furthermore, there was no difference in endocrine dysfunctions between the two groups. There was no correlation between the severity of hormonal deficiency and the clinical severity of SAH grade by Hunt and Hess and radiological grade of SAH by Fisher′s grade. Conclusion: Hormonal deficiencies are not uncommon in patients with SAH. There is no difference in hormonal deficiencies and severity of hypopituitarism in patients with SAH due to A-com and MCA bleed.

  3. MONOPOLAR ELECTROCAUTERY VS SURGICAL CLIPS IN CONTROL OF CYSTIC ARTERY IN LAPAROSCOPIC CHOLECYSTECTOMY: A COMPARATIVE STUDY

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    Ridipta Sekha

    2016-04-01

    Full Text Available BACKGROUND Laparoscopic cholecystectomy has been extensively accepted since Mouret first successfully introduced the procedure in 1987. During this procedure the cystic artery can be controlled using surgical clips, harmonic scalpel and ligature or monopolar cautery. The extensive use of surgical clips in laparoscopic surgery has led to a variety of complications. Monopolar electrocoagulation can be used to control the cystic artery as it is cheap and universally available. Hence in this study, we compared monopolar electrocautery with clip application for securing haemostasis and to identify the safest and least complicated way for haemostasis of the cystic artery in laparoscopic cholecystectomy. METHODS A retrospective analysis of 201 patients were done who were planned for laparoscopic cholecystectomy. Among them 3 were converted to open cholecystectomy due to intraoperative bleeding. The rest 198 patients underwent successful laparoscopic cholecystectomy. In 42 patients the cystic artery was ligated using Ligaclip 300, while in 156 patients the artery was coagulated using monopolar cautery with hook. The patients were observed for any incidences of post-operative haemorrhage and bile leak, difference in length of hospital stay and post-operative complications. RESULTS The mean age was 40.26 years with M:F ratio 1:4. About 86% (135 and 88% (37 patients, respectively in electrocautery and Ligaclip group were discharged on the first post-operative day itself. Only 3 (1.5% patients, 2 in electrocautery and 1 in Ligaclip group developed post-operative port site infection. These differences were not statistically significant. CONCLUSION We conclude that monopolar electrocautery can be used as a safer alternative to surgical clips in control of cystic artery, especially in developing countries.

  4. Tympanic, Infrared Skin, and Temporal Artery Scan Thermometers Compared with Rectal Measurement in Children: A Real-Life Assessment

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    Karel Allegaert, MD, PhD

    2014-12-01

    Conclusions: All noninvasive techniques underperformed compared with rectal measurement. The temporal artery scan deviations were smallest, but all noninvasive techniques overestimate lower temperatures and underestimate higher temperatures compared with rectal measurement. In our hands, temporal artery scan measurement seems to be second best, but not yet ideal.

  5. Metabolic syndrome and coronary artery disease in Ossabaw compared with Yucatan swine.

    Science.gov (United States)

    Neeb, Zachary P; Edwards, Jason M; Alloosh, Mouhamad; Long, Xin; Mokelke, Eric A; Sturek, Michael

    2010-08-01

    Metabolic syndrome (MetS), a compilation of associated risk factors, increases the risk of type 2 diabetes and coronary artery disease (CAD, atherosclerosis), which can progress to the point of artery occlusion. Stents are the primary interventional treatment for occlusive CAD, and patients with MetS and hyperinsulinemia have increased restenosis. Because of its thrifty genotype, the Ossabaw pig is a model of MetS. We tested the hypothesis that, when fed high-fat diet, Ossabaw swine develop more features of MetS, greater native CAD, and greater stent-induced CAD than do Yucatan swine. Animals of each breed were divided randomly into 2 groups and fed 2 different calorie-matched diets for 40 wk: control diet (C) and high-fat, high-cholesterol atherogenic diet (H). A bare metal stent was placed in the circumflex artery, and pigs were allowed to recover for 3 wk. Characteristics of MetS, macrovascular and microvascular CAD, in-stent stenosis, and Ca(2+) signaling in coronary smooth muscle cells were evaluated. MetS characteristics including, obesity, glucose intolerance, hyperinsulinemia, and elevated arterial pressure were elevated in Ossabaw swine compared to Yucatan swine. Ossabaw swine with MetS had more extensive and diffuse native CAD and in-stent stenosis and impaired coronary blood flow regulation compared with Yucatan. In-stent atherosclerotic lesions in Ossabaw coronary arteries were less fibrous and more cellular. Coronary smooth muscle cells from Ossabaw had impaired Ca(2+) efflux and intracellular sequestration versus cells from Yucatan swine. Therefore, Ossabaw swine are a superior model of MetS, subsequent CAD, and cellular Ca(2+) signaling defects, whereas Yucatan swine are leaner and relatively resistant to MetS and CAD.

  6. TNM Method Results Compared with Finite Element Analysis for a 30 KW SCIM Motor

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    A. Ravi Prasad

    2015-10-01

    Full Text Available The Thermal network model (TNM of ten node 37 thermal resistances is considered as the highly detailed one for thermal distribution of all the TNM models. This model is reported to be the one that can take care of most of the complexities in geometry and estimation of convective heat transfer coefficients. Results obtained for the 30 KW motor using the above TNM model have been compared with that of Finite element Analysis using ANSYS. Listing of the MATLAB programs is presented as annexure.

  7. [Comparative characteristics of the open and endovascular methods of treatment for carotid artery stenoses].

    Science.gov (United States)

    Krotovskiĭ, G S; Uchkin, I G; Shugushev, Z Kh; Zudin, A M; Kagdasarian, A G

    2010-01-01

    The article is dedicated to the problem concerning treatment for stenoses of the extracranial portions of carotid arteries. From March 2004 to November 2009 at the Department of Vascular Surgery No 2 of the N. A. Semashko Central Clinical Hospital No 2 we treated a total of 364 patients presenting with stenotic lesions of the extracranial portion of the carotid arteries. Of these, 176 patients underwent revascularization of the carotid basin: 120 patients endured open carotid endarterectomy (CEAE), 56 patients sustained carotid angioplasty and stenting (CAS), with a total of 128 CEAE and 67 CAS interventions performed. The following conclusion was made: with high skill of surgeons and broad experience in carrying out revascularization of the carotid basin, the CEAE and CAS procedures possess comparable efficacy and safety with CEAE possessing reliable advantage in terms of the parameters of the patient's quality of life.

  8. [Comparative assessment of immediate outcomes of surgical treatment of patients with coronary artery disease and lesion of the brachiocephalic arteries].

    Science.gov (United States)

    Drozhzhin, E V; Ibragimov, O R; Koval'chuk, D N; Efanov, Iu M; Zor'kin, A A; Ibragimova, E A; Urvantseva, I A

    2014-01-01

    From 2000 to 2011, a total of 52 patients with combined atherosclerotic lesions of the coronary and brachiocephalic arteries were subjected to a single-stage operation. Depending on the type of operative intervention, all patients were subdivided into two groups: Group One comprising 13 patients who underwent coronary artery bypass grafting (CABG) in a combination with simultaneous stenting of the internal carotid artery, and Group Two consisting of 39 patients subjected to CABG with simultaneous carotid endarterectomy. Assessing the intraoperative parameters revealed that in Group One patients the average duration of operations was significantly lower (179.6±6.4 minutes versus 273.2±5.6 minutes in Group Two, partery with the development of intestinal gangrene and peritonitis. In the structure of hospital complications cardiac insufficiency was prevalent (23.1% and 59.0% for Groups One and Group Two patients, respectively, pcoronary and brachiocephalic arteries makes it possible to increase the overall survival rate in patients suffering this disease and to decrease the incidence rate of ischaemic impairments of the coronary and cerebral circulation. The hybrid method of treatment on arteries of various vascular basins may be an alternative to carotid endarterectomy and CABG, especially in patients running high surgical risk.

  9. A comparative study on the customized design of mandibular reconstruction plates using finite element method

    Directory of Open Access Journals (Sweden)

    Abdulrahman Al-Ahmari

    2015-07-01

    Full Text Available Mandible defects and its deformities are serious complications and its precise reconstruction is one of the most challenging tasks in oral maxillofacial surgery. The commercially available standard mandible implants are manually bended before surgery to custom fit the patient’s jaw. A slight mismatch in the plate and bone alignment may result in the implant failure. However, with the integration of computer-aided design, rapid prototyping, and advanced imaging systems (computed tomography or magnetic resonance imaging, it is possible to produce a customized mandible implant that can precisely fit the patient’s jaw. The aim of this article is to compare a new design of customized mandible implant (sinewave plate and compare it with the commonly used straight implant design. The finite element–simulated results reveal that the commonly used straight reconstruction plates are more prone to loosening of the screws due to its higher strain concentration on the screw hole when compared to newly designed sinewave reconstruction plate. Moreover, the straight plate is more sensitive to the chewing load variations and develops almost 20% increase in the stresses when compared to sinewave plate. The study reveals that the sinewave reconstruction plate can significantly enhance the stability and safety of the mandible implant.

  10. Comparative Transcriptome Analysis Identifies CCDC80 as a Novel Gene Associated with Pulmonary Arterial Hypertension

    Directory of Open Access Journals (Sweden)

    Yuhei eNishimura

    2016-06-01

    Full Text Available Pulmonary arterial hypertension (PAH is a heterogeneous disorder associated with a progressive increase in pulmonary artery resistance and pressure. Although various therapies have been developed, the 5-year survival rate of PAH patients remains low. There is thus an important need to identify novel genes that are commonly dysregulated in PAH of various etiologies and could be used as biomarkers and/or therapeutic targets. In this study, we performed comparative transcriptome analysis of five mammalian PAH datasets downloaded from a public database. We identified 228 differentially expressed genes (DEGs from a rat PAH model caused by inhibition of vascular endothelial growth factor receptor under hypoxic conditions, 379 DEGs from a mouse PAH model associated with systemic sclerosis, 850 DEGs from a mouse PAH model associated with schistosomiasis, 1598 DEGs from one cohort of human PAH patients, and 4260 DEGs from a second cohort of human PAH patients. Gene-by-gene comparison identified four genes that were differentially upregulated or downregulated in parallel in all five sets of DEGs. Expression of coiled-coil domain containing 80 (CCDC80 and anterior gradient 2 genes was significantly increased in the five datasets, whereas expression of SMAD family member 6 and granzyme A was significantly decreased. Weighted gene co-expression network analysis revealed a connection between CCDC80 and collagen type I alpha 1 (COL1A1 expression. To validate the function of CCDC80 in vivo, we knocked out ccdc80 in zebrafish using the clustered regularly interspaced short palindromic repeats (CRISPR/Cas9 system. In vivo imaging of zebrafish expressing a fluorescent protein in endothelial cells showed that ccdc80 deletion significantly increased the diameter of the ventral artery, a vessel supplying blood to the gills. We also demonstrated that expression of col1a1 and endothelin-1 mRNA was significantly decreased in the ccdc80-knockout zebrafish. Finally, we

  11. Comparable three months' outcome of total arterial revascularization versus conventional coronary surgery: Copenhagen Arterial Revascularization Randomized Patency and Outcome trial

    DEFF Research Database (Denmark)

    Damgaard, S.; Lund, J.T.; Lilleor, N.B.;

    2008-01-01

    .9 in the conventional group (P = .004). Three months' follow-up for the arterial versus conventional groups showed the following: deaths: 1 (0.6%) versus 0; stroke: 3 (1.9%) versus 3 (1.8%); myocardial infarction: 6 (3.7%) versus 4 (2.4%); sternal wound reoperation: 4 (2.5%) versus 0 (P = .054); arm and leg wound...

  12. Cost-utility of enoxaparin compared with unfractionated heparin in unstable coronary artery disease

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    Milne Ruairidh

    2001-10-01

    Full Text Available Abstract Background Low molecular weight heparins hold several advantages over unfractionated heparin including convenience of administration. Enoxaparin is one such heparin licensed in the UK for use in unstable coronary artery disease (unstable stable angina and non-Q wave myocardial infarction. In these patients, two large randomised controlled trials and their meta-analysis showed small benefits for enoxaparin over unfractionated heparin at 30–43 days and potentially at one year. We found no relevant published full economic evaluations, only cost studies, one of which was conducted in the UK. The other studies, from the US, Canada and France, are difficult to interpret since their resource use and costs may not reflect UK practice. Methods We aimed to compare the benefits and costs of short-term treatment (two to eight days with enoxaparin and unfractionated heparin in unstable coronary artery disease. We used published data sources to estimate the incremental cost per quality adjusted life year (QALY, adopting a NHS perspective and using 1998 prices. Results The base case was a 0.013 QALY gain and net cost saving of £317 per person treated with enoxaparin instead of unfractionated heparin. All but one sensitivity analysis showed net savings and QALY gains, the exception (the worst case being a cost per QALY of £3,305. Best cases were a £495 saving and 0.013 QALY gain, or a £317 saving and 0.014 QALY gain per person. Conclusions Enoxaparin appears cost saving compared with unfractionated heparin in patients with unstable coronary artery disease. However, cost implications depend on local revascularisation practice.

  13. Research related to improved computer aided design software package. [comparative efficiency of finite, boundary, and hybrid element methods in elastostatics

    Science.gov (United States)

    Walston, W. H., Jr.

    1986-01-01

    The comparative computational efficiencies of the finite element (FEM), boundary element (BEM), and hybrid boundary element-finite element (HVFEM) analysis techniques are evaluated for representative bounded domain interior and unbounded domain exterior problems in elastostatics. Computational efficiency is carefully defined in this study as the computer time required to attain a specified level of solution accuracy. The study found the FEM superior to the BEM for the interior problem, while the reverse was true for the exterior problem. The hybrid analysis technique was found to be comparable or superior to both the FEM and BEM for both the interior and exterior problems.

  14. A randomised trial comparing weight loss with aerobic exercise in overweight individuals with coronary artery disease

    DEFF Research Database (Denmark)

    Pedersen, Lene Rørholm Engelbrecht; Olsen, Rasmus H; Jürs, Anders

    2015-01-01

    BACKGROUND: We aimed to compare the effect of aerobic interval training (AIT) versus a low energy diet (LED) on physical fitness, body composition, cardiovascular risk factors and symptoms in overweight individuals with coronary artery disease (CAD). METHODS AND DESIGN: Seventy non...... their antihypertensive treatment reduced following LED (between-group, p = 0.032). Canadian Cardiovascular Society (CCS), New York Heart Association (NYHA) and anxiety scores were improved, while depressive symptoms remained unchanged. Intention-to-treat analyses including 65 participants (93%) were similar to per...... protocol analysis. CONCLUSION: Both interventions were feasible and effective in achieving the desired effects. LED was superior in improving body composition and blood pressure, whereas effects on lipids and symptoms were similar in the two groups. Thus, both AIT and LED improve the cardiovascular risk...

  15. Comparing Two Ovulation Induction Methods by Brachial Artery Ultrasonography in Infertile Women with Polycystic Ovary Syndrome

    Directory of Open Access Journals (Sweden)

    B Ghorbani Yekta

    2012-07-01

    Full Text Available Background: Endothelial dysfunction can influence fertility rate in women with polycystic ovary syndrome (PCOS as flow mediated dilatation (FMD is impaired in patients with the disease. The aim of this study was to compare two methods of ovulation induction by letrozole or letrozole plus human menopausal gonadotropins (HMGs in infertile women with PCOS who were resistant to clomiphene citrate based on brachial artery ultrasound findings.Methods: In this double -blind randomized clinical trial, 59 infertile women who had the inclusion criteria for PCOS were evaluated in the Infertility Clinic of Shariati Hospital in Tehran, Iran in 2010-2011. The patients were assigned to two letrozole and letrozole plus HMG groups and were evaluated for FMD in the brachial artery by transvaginal ultrasonography. Later, the values were recorded and analyzed statistically.Results: In the letrozole group, infertility treatment was successful in 15 (57.7% but it failed in 11 (42.3% patients. In letrozole plus HMG group, the treatment was successful in 18 (54.5% while it failed in 15 (45.5% patients. The mean FMD values in the groups with successful and unsuccessful treatment results were 19.42±10% and 18.57±7.2%, respectively, but the difference was not statistically significant (P=0.712. Moreover, the average endometrial thickness in groups with successful and unsuccessful treatment results were 8.4±1.3 mm and 9.8±3.9 mm, respectively but the difference was not significant either (P=0.06.Conclusion: In infertile women with polycystic ovary syndrome that are resistant to clomiphene, letrozole or letrozole combined with gonadotropin can be equally effective for ovulation induction.

  16. Comparative effects of enoxaparin and heparin on arterial and venous clot lysis with alteplase in dogs.

    Science.gov (United States)

    Stassen, J M; Rapold, H J; Vanlinthout, I; Collen, D

    1993-05-03

    The effects of Enoxaparin with a specific anti-thrombin (anti-IIa) activity of 32 U/mg and a specific anti-factor-XA (anti-Xa) activity of 96 U/mg, and of heparin with a specific anti-IIa and anti-Xa activity of 192 U/mg, on thrombolysis with alteplase (Actilyse) were compared in a randomized blinded study using a combined arterial and venous thrombosis model in the dog. All dogs received an intravenous bolus of 5 mg/kg lysine-acetyl salicylate and 0.5 mg/kg alteplase over 60 min. Twenty-eight dogs were randomly assigned to seven treatment groups: placebo, Enoxaparin 1.5, 3 or 6 mg/kg, or heparin 0.5, 1 or 2 mg/kg, given as a 50% intravenous bolus and a 50% infusion over 2 h. Steady-state plasma levels ranged from 0.37 to 1.0 anti-IIa U/ml and 0.9 to 3.1 anti-Xa U/ml for Enoxaparin and from 0.4 to 2.3 anti-IIa U/ml and 0.42 to 3.2 anti-Xa U/ml for heparin. The activated thromboplastin time with 6 mg/kg Enoxaparin prolonged to 94 +/- 19 s and with 2 mg/kg heparin to > 150 s. The time to reflow was 120 +/- 36 min with placebo, 19 +/- 5 min with 6 mg/kg Enoxaparin (p = 0.03 vs control), and 22 +/- 5 min with 2 mg/kg of heparin (p = 0.03 vs control). Arterial patency, expressed in min reflow during the 180 min observation period correlated significantly with the dose of anticoagulant given (r = 0.73, p = 0.003 for Enoxaparin and r = 0.61, p = 0.012 for heparin).(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Comparing DG and Nedelec finite element discretisations of the second-order time-domain Maxwell equation

    NARCIS (Netherlands)

    Sármány, D.; Botchev, M.A.; Vegt, van der J.J.W.; Verwer, J.G.

    2009-01-01

    This article compares the discontinuous Galerkin finite element method (DG-FEM) with the $H(\\mathrm{curl})$-conforming FEM in the discretisation of the second-order time-domain Maxwell equations with possibly nonzero conductivity term. While DG-FEM suffers from an increased number of degrees of free

  18. Minimally invasive compared to conventional approach for coronary artery bypass grafting improves outcome

    Directory of Open Access Journals (Sweden)

    Jitumoni Baishya

    2017-01-01

    Full Text Available Introduction: Minimally invasive (MI cardiac surgery is a rapidly gaining popularity, globally as well as in India. We aimed to compare the outcome of MI to the conventional approach for coronary artery bypass graft (CABG surgery. Methods: This prospective, comparative study was conducted at a tertiary care cardiac surgical center. All patients who underwent CABG surgery via MI approach (MI group from July 2015 to December 2015 were enrolled and were compared against same number of EuroSCORE II matched patients undergoing CABG through conventional mid-sternotomy approach (CON group. Demographic, intra- and post-operative variables were collected. Results: In MI group, duration of the surgery was significantly longer (P = 0.029. Intraoperative blood loss lesser (P = 0.002, shorter duration of ventilation (P = 0.002, shorter Intensive Care Unit stay (P = 0.004, shorter hospital stay (P = 0.003, lesser postoperative analgesic requirements (P = 0.027, and lower visual analog scale scores on day of surgery (P = 0.032 and 1 st postoperative day (P = 0.025. No significant difference in postoperative blood loss, blood transfusion, or duration of inotrope requirement observed. There was no conversion to mid-sternotomy in any patients, 8% of patients had desaturation intraoperatively. There was no operative mortality. Conclusion: MI surgery is associated with lesser intraoperative blood loss, better analgesia, and faster recovery.

  19. Comparing an evolved finite state controller for hybrid system to a lookahead design

    DEFF Research Database (Denmark)

    Dupuis, Jean-Francois; Fan, Zhun

    2010-01-01

    This paper presents a comparison of an evolutionary methodology for evolving finite state controller to the lookahead controller for hybrid system. To illustrate the advantages and disadvantages of both controllers two case studies, namely a two-tanks system and a single-input double-output DC...

  20. A comparative study on transradial vs transfemoral artery access for primary percutaneous coronary intervention in patients with acute myocardial infarction

    Institute of Scientific and Technical Information of China (English)

    傅向华

    2003-01-01

    A comparative study on transradial vs transfemoral artery access for primary percutaneous coronary intervention in patients with acute myocardial infarction!050000$河北医科大学第二医院河北医科大学心脏介入中心@傅向华

  1. Comparing Supervised Exercise Therapy to Invasive Measures in the Management of Symptomatic Peripheral Arterial Disease

    Directory of Open Access Journals (Sweden)

    Thomas Aherne

    2015-01-01

    Full Text Available Peripheral arterial disease (PAD is associated with considerable morbidity and mortality. Consensus rightly demands the incorporation of supervised exercise training (SET into PAD treatment protocols. However, the exact role of SET particularly its relationship with intervention requires further clarification. While supervised exercise is undoubtedly an excellent tool in the conservative management of mild PAD its use in more advanced disease as an adjunct to open or endovascular intervention is not clearly defined. Indeed its use in isolation in this cohort is incompletely reported. The aim of this review is to clarify the exact role of SET in the management of symptomatic PAD and in particular to assess its role in comparison with or as an adjunct to invasive intervention. A systematic literature search revealed a total 11 randomised studies inclusive of 969 patients. All studies compared SET and intervention with monotherapy. Study results suggest that exercise is a complication-free treatment. Furthermore, it appears to offer significant improvements in patients walk distances with a combination of both SET and intervention offering a superior walking outcome to monotherapy in those requiring invasive measures.

  2. [Comparative anatomical study of the ventral brain arteries of the Pudu pudu (Molina, 1782) with those of the cow].

    Science.gov (United States)

    Schweitzer-Delaunoy, W

    1997-06-01

    Comparative anatomical study of the ventral brain arteries of the Pudú pudu (Molina, 1782) with those of the cow. A comparison using the corrosion method was made between Pudú pudu (Molina, 1782) ventral brain arteries and those of the cow. The Pudú's Rete mirabile epidurale rostrale (Nomina Anatomica Veterinaria, 1994) is ventrally formed by branches of the A. maxillaris, and caudally formed by the A. vertebralis. The Hypophysis is surrounded by the Rete mirabile rostrale. The lateral parts are rostrally joined to that gland by a thin vascular bridge and caudally by thick arteries. The Pudú's Circulus arteriosus cerebri asymmetrical, that is, on the right side the A. cerebri rostralis ends in the A. cerebri media. The left-side A. cerebri rostralis irrigates every rostral portion of the encephalon. In the cow, practically the same arteries come out of the Circulus arteriosus cerebri, which is not asymmetrical. The A. cerebri caudalis comes first out of the A. communicans caudalis and then the branches for the Pons, and finally the A. cerebelli rostralis. In this species, there are arterial blocks that are not present in Pudú.

  3. Comparative Evaluation of Tractor Trolley Axle by Using Finite Element Analysis Approach

    Directory of Open Access Journals (Sweden)

    Sanjay Aloni

    2012-04-01

    Full Text Available Tractor trolley or trailers are very popular and cheaper mode of goods transport in rural as well as urban area. But these trailers are manufactured in small scale to moderate scale industry. Especially in the small- and middle-scale agricultural machinery industry, insufficient use of new technology and new design features can cause problems such as breakdowns and failures during field operations. In Present work finite element analysis approach is used to modify existing rear axle of tractor trolley. Fatigue failure of the rear axle finite element model was predicted after the dynamic load was imposed on it. For analysis, a 6.0 ton 2 wheeler tractor trolley i.e. semitrailer manufactured by Awachat Industries Ltd., Wardha is selected. The finite element analysis of existing rear axle of tractor trolley revealed the stresses distribution on rear axle. So, an effort is made to modify the design of existing rear axle along with change of material so that advantage of weight reduction along with safe stress can be obtained.

  4. An Analysis Technique/Automated Tool for Comparing and Tracking Analysis Modes of Different Finite Element Models

    Science.gov (United States)

    Towner, Robert L.; Band, Jonathan L.

    2012-01-01

    An analysis technique was developed to compare and track mode shapes for different Finite Element Models. The technique may be applied to a variety of structural dynamics analyses, including model reduction validation (comparing unreduced and reduced models), mode tracking for various parametric analyses (e.g., launch vehicle model dispersion analysis to identify sensitivities to modal gain for Guidance, Navigation, and Control), comparing models of different mesh fidelity (e.g., a coarse model for a preliminary analysis compared to a higher-fidelity model for a detailed analysis) and mode tracking for a structure with properties that change over time (e.g., a launch vehicle from liftoff through end-of-burn, with propellant being expended during the flight). Mode shapes for different models are compared and tracked using several numerical indicators, including traditional Cross-Orthogonality and Modal Assurance Criteria approaches, as well as numerical indicators obtained by comparing modal strain energy and kinetic energy distributions. This analysis technique has been used to reliably identify correlated mode shapes for complex Finite Element Models that would otherwise be difficult to compare using traditional techniques. This improved approach also utilizes an adaptive mode tracking algorithm that allows for automated tracking when working with complex models and/or comparing a large group of models.

  5. Multi-section CT angiography compared with digital subtraction angiography in diagnosing major arterial hemorrhage in inflammatory pancreatic disease

    Energy Technology Data Exchange (ETDEWEB)

    Hyare, Harpreet [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom)]. E-mail: hhyare@doctors.org.uk; Desigan, Sharmini [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom); Nicholl, Helen [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom); Guiney, Michael J. [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom); Brookes, Jocelyn A. [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom); Lees, William R. [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom)

    2006-08-15

    Purpose: Major arterial hemorrhage is an uncommon but serious complication of pancreatitis with high morbidity and mortality. Digital subtraction angiography (DSA) has long been the gold standard for the detection of a visceral artery pseudoaneurysm or for the site of active bleeding in patients with pancreatitis. Multi-section CT angiography is a minimally invasive technique which can provide high-resolution and high-contrast images of the arterial lumen and wall, with a much lower risk of complication and morbidity compared to DSA. The aim of this study was to determine the accuracy of multi-section CT angiography for the diagnosis of arterial complications of inflammatory pancreatitic disease. Materials and methods: A retrospective analysis of all patients undergoing visceral angiography for major bleeding as a complication of pancreatitis between 1998 and 2004 was performed. Twenty-nine studies in 25 patients (20 males, 5 females) with a mean age of 50.9 years (range 11-67 years) were identified where multi-section CT angiography was performed in the 24 h preceding the digital subtraction angiogram. Results: Digital subtraction angiography detected a pseudoaneurysm or contrast extravasation in 19 studies and no bleeding was demonstrated in 9 studies. CT angiography correctly identified the site and type of bleeding in 18 of the 19 positive studies. CT angiography detected extravasation of contrast in one study that was not demonstrated on digital subtraction angiography. The sensitivity and specificity for multi-section CT angiography for the detection of major arterial bleeding on a background of pancreatitis were 0.947 and 0.900, respectively. Conclusion: Multi-section CT angiography is a sensitive and accurate technique for the detection of major arterial hemorrhage in inflammatory pancreatic disease and should be considered as the first investigation in the management of these patients.

  6. Comparing Blast Effects on Human Torso Finite Element Model against Existing Lethality Curves

    Science.gov (United States)

    2010-07-15

    Torso FEM Development Geometry The anatomical geometry for the finite element model originated from the geometry supplied by the 4D NURBS -based...by the WORLDSID project (Moss 2000). The geometry was imported as NURBS surfaces and manipulated to contain distinct organs and bones. The Human...Volume 40, Issue 1, 2007, Pages 125‐ 136.  Segars, W.P. Development of a new dynamic  NURBS ‐based cardiac‐torso (NCAT) phantom. The  University of North

  7. Total aortic arch replacement: superior ventriculo-arterial coupling with decellularized allografts compared with conventional prostheses.

    Directory of Open Access Journals (Sweden)

    Alexander Weymann

    Full Text Available To date, no experimental or clinical study provides detailed analysis of vascular impedance changes after total aortic arch replacement. This study investigated ventriculoarterial coupling and vascular impedance after replacement of the aortic arch with conventional prostheses vs. decellularized allografts.After preparing decellularized aortic arch allografts, their mechanical, histological and biochemical properties were evaluated and compared to native aortic arches and conventional prostheses in vitro. In open-chest dogs, total aortic arch replacement was performed with conventional prostheses and compared to decellularized allografts (n = 5/group. Aortic flow and pressure were recorded continuously, left ventricular pressure-volume relations were measured by using a pressure-conductance catheter. From the hemodynamic variables end-systolic elastance (Ees, arterial elastance (Ea and ventriculoarterial coupling were calculated. Characteristic impedance (Z was assessed by Fourier analysis.While Ees did not differ between the groups and over time (4.1±1.19 vs. 4.58±1.39 mmHg/mL and 3.21±0.97 vs. 3.96±1.16 mmHg/mL, Ea showed a higher increase in the prosthesis group (4.01±0.67 vs. 6.18±0.20 mmHg/mL, P<0.05 in comparison to decellularized allografts (5.03±0.35 vs. 5.99±1.09 mmHg/mL. This led to impaired ventriculoarterial coupling in the prosthesis group, while it remained unchanged in the allograft group (62.5±50.9 vs. 3.9±23.4%. Z showed a strong increasing tendency in the prosthesis group and it was markedly higher after replacement when compared to decellularized allografts (44.6±8.3 dyn·sec·cm(-5 vs. 32.4±2.0 dyn·sec·cm(-5, P<0.05.Total aortic arch replacement leads to contractility-afterload mismatch by means of increased impedance and invert ventriculoarterial coupling ratio after implantation of conventional prostheses. Implantation of decellularized allografts preserves vascular impedance thereby improving

  8. Effectiveness of sublingual nitroglycerin before puncture compared with conventional intra-arterial nitroglycerin in transradial procedures: a randomized trial

    Energy Technology Data Exchange (ETDEWEB)

    Turan, Burak, E-mail: drburakturan@gmail.com; Daşlı, Tolga; Erkol, Ayhan; Erden, İsmail

    2015-10-15

    Aim: Sublingual (SL) nitroglycerin administered before radial artery puncture can improve cannulation success and decrease the incidence of radial artery spasm (RAS) compared with intra-arterial (IA) nitroglycerin in transradial procedures. Methods: Patients undergoing diagnostic transradial angiography were randomized to IA (200 mcg) or SL (400 mcg) nitroglycerin. Primary endpoints were puncture time and puncture attempts. Secondary endpoint was the incidence of RAS. Results: Total of 101 participants (mean age 60 ± 11 years, 53% male) were randomized (51 in IA and 50 in SL groups). Puncture time (50 [36–75] vs 50 [35–90] sec), puncture attempts (1.18 ± 0.48 vs 1.20 ± 0.49), multiple punctures (13.7 vs 16.0%) and RAS (19.6 vs 24.0%) were not statistically different between IA vs SL groups respectively. A composite endpoint of all adverse events related to transradial angiography (multiple punctures, RAS, access site crossover, hypotension/bradycardia associated with nitroglycerin and radial artery occlusion) was very similar in IA vs SL groups (39 vs 40%, respectively). However puncture time was significantly longer with SL nitroglycerin in patients < 1.65 m height (47 [36–66] vs 63 [41–110] sec, p = 0.042). Multiple punctures seemed higher with SL nitroglycerin in patients with diabetes (0 vs 30%, p = 0.028) or in patients < 1.65 m height (7.4 vs 25%, p = 0.085). Likewise, RAS with SL nitroglycerin seemed more frequent in smokers compared to IA nitroglycerin (0 vs 27%, p = 0.089). Conclusions: SL nitroglycerin was not different from IA nitroglycerin in terms of efficiency and safety in overall study population. However it may be inferior to IA nitroglycerin in certain subgroups (shorter individuals, diabetics and smokers). - Highlights: • Improvement in radial artery puncture time and success with subcutaneous nitrate was reported. • Giving nitrate sublingually may have vasodilation along entire length of radial artery and may prevent RAS

  9. Uterine artery remodeling in pseudopregnancy is comparable to that in early pregnancy.

    NARCIS (Netherlands)

    Heijden, O.W. van der; Essers, Y.P.; Spaanderman, M.E.A.; Mey, J.G. de; Eys, G. van; Peeters, L.L.

    2005-01-01

    During pregnancy, the lumenal diameter and wall mass of the uterine artery (UA) increase, most likely in response to the increased hemodynamic strain resulting from the chronically elevated uterine blood flow (UBF). In this remodeling process, the phenotype of vascular smooth-muscle cells (VSMC) is

  10. Stress distribution among periodontally compromised abutments: A comparative study using three-dimensional finite element analysis

    Directory of Open Access Journals (Sweden)

    Rajkiran Chitumalla

    2012-01-01

    Full Text Available Aims: The aim of the study was to evaluate the stress distribution patterns in teeth and supporting structures of fixed prosthesis and design modifications in a fixed prosthesis with either normal or reduced bone support of an additional abutment. Study was also undertaken to disprove Ante′s law. Materials and Methods: Main models and variations of main models (modification 1, 2, 3, 4, 5, 6, 7, 8 were subjected to 200 N at angulations of 90° and 15° on functional cusps. Results for each loading were obtained as stress distribution color images and numerical values were recorded. A three-dimensional finite element analysis study of variations of normal models was performed using two finite element softwares, namely PRO-Engineer wildfire version 1.0 manufacturer: Parametric technology corporation, Needham, MA 02494 U.S.A. Results: When periodontal compromised abutment teeth was splinted with an additional abutment an increase of stress was observed in periodontally compromised abutments so an additional abutment is not required. Eventhough the pericemental area of compromised abutments with an additional abutment (canine was more than the combined pericemental area of pontics to be replaced, stress generated was more on abutments. This disproves Ante′s law. Hence, it may be a reference, but should not be the ultimate criterion in determining the number of multiple abutments. Conclusions: When periodontal compromised abutment teeth was splinted with an additional abutment an increase of stress was observed in periodontally compromised abutments so an additional abutment is not required. Even though the pericemental area of compromised abutments with an additional abutment (canine was more than combined pericemental area of pontics to be replaced, stress generated was more on abutments. This disproves Ante′s law. Hence, it may be a reference, but should not be the ultimate criterion in determining the number of multiple abutments.

  11. A randomised trial comparing the effect of exercise training and weight loss on microvascular function in coronary artery disease

    DEFF Research Database (Denmark)

    Olsen, Rasmus Huan; Pedersen, Lene Rørholm; Jürs, Anders

    2015-01-01

    BACKGROUND: Coronary microvascular function is associated with outcome and is reduced in coronary artery disease (CAD) and obesity. We compared the effect of aerobic interval training (AIT) and weight loss on coronary flow reserve (CFR) and peripheral vascular function in revascularised obese CAD...... might impact prognosis of CAD through improvement of coronary microvascular function. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01724567....

  12. To compare the effect of Telmisartan with Metoprolol on arterial stiffness in hypertension: Prospective randomized parallel group trial

    Science.gov (United States)

    Sumbria, Minakshi; Negi, Prakash C.; Sahai, Ashok K.; Kaundal, Purshotam K.

    2014-01-01

    Background Hypertension is often complicated by increased arterial stiffness and is an independent predictor of adverse cardiovascular (CV) outcome. Beta blockers and angiotensin receptor blockers (ARBs) are commonly used antihypertensive agents. The effect of beta blockers and ARBs on arterial stiffness has not been compared adequately. The aim of the present study is to compare the effect of telmisartan with metoprolol on arterial stiffness in hypertensive patients in prospective open label randomized parallel group intervention study. Methods 100 patients of hypertension, not on any antihypertensive agents, were enrolled after obtaining informed consent. Baseline recording of data related to demographics, CV risk factors, anthropometry and BP were made. Arterial stiffness was measured noninvasively by recording pulse wave velocity (PWV) using periscope (Genesis medical system). Left ventricular (LV) mass was measured using 2D guided M-mode echocardiography. Blood sugar, renal function, lipids and uric acid estimations were done in fasting state. Patients were randomized to receive metoprolol and telmisartan using stratified randomization technique. Dose of the study drugs were titrated to achieve target BP of <140/90 mmHg. Data related to PWV, BP, anthropometry and blood biochemistry was repeated after 6 months of treatment with study drugs. Results Telmisartan resulted in significantly greater reduction in arterial stiffness index (ASI) in left and right lower limb arterial bed (39.9 ± 11.7 vs. 46.8 ± 17.0 m/s, p < 0.02) and (36.4 ± 9.6 vs. 44.86 ± 15.1 m/s, p < 0.002) respectively and systolic blood pressure (SBP) (−4.9 mmHg with 95% C.I. of −8.0–1.7 mmHg, p < 0.003) compared to metoprolol. Reduction in diastolic blood pressure (DBP) in telmisartan and metoprolol groups was not different statistically (−1.0 mmHg with 95% C.I. of −3.3–1.2 mmHg, p < 0.3). The change in LV mass was not significantly different between the

  13. Aortic root performance after valve sparing procedure: a comparative finite element analysis.

    Science.gov (United States)

    Soncini, Monica; Votta, Emiliano; Zinicchino, Silvia; Burrone, Valeria; Mangini, Andrea; Lemma, Massimo; Antona, Carlo; Redaelli, Alberto

    2009-03-01

    David and Yacoub sparing techniques are the most common procedures adopted for the surgical correction of aortic root aneurysms. These surgical procedures entail the replacement of the sinuses of Valsalva with a synthetic graft, inside which the cusps are re-suspended. Root replacement by a synthetic graft may result in altered valve behaviour both in terms of coaptation and stress distribution, thus leading to the failure of the correction. A finite element approach was used to investigate this phenomenon; four 3D models of the aortic root were developed to simulate the root in physiological, pathological and post-operative conditions after the two different surgical procedures. The physiological 3D geometrical model was developed on the basis of anatomical data obtained from echocardiographic images; it was then modified to obtain the pathological and post-operative models. The effectiveness of both techniques was assessed by comparison with the first two simulated conditions, in terms of stresses acting on the root, leaflet coaptation and interaction between leaflets and the graft during valve opening. Results show that both sparing techniques are able to restore aortic valve coaptation and to reduce stresses induced by the initial root dilation. Nonetheless, both techniques lead to altered leaflet kinematics, with more evident alterations after David repair.

  14. Finite state projection based bounds to compare chemical master equation models using single-cell data

    Science.gov (United States)

    Fox, Zachary; Neuert, Gregor; Munsky, Brian

    2016-08-01

    Emerging techniques now allow for precise quantification of distributions of biological molecules in single cells. These rapidly advancing experimental methods have created a need for more rigorous and efficient modeling tools. Here, we derive new bounds on the likelihood that observations of single-cell, single-molecule responses come from a discrete stochastic model, posed in the form of the chemical master equation. These strict upper and lower bounds are based on a finite state projection approach, and they converge monotonically to the exact likelihood value. These bounds allow one to discriminate rigorously between models and with a minimum level of computational effort. In practice, these bounds can be incorporated into stochastic model identification and parameter inference routines, which improve the accuracy and efficiency of endeavors to analyze and predict single-cell behavior. We demonstrate the applicability of our approach using simulated data for three example models as well as for experimental measurements of a time-varying stochastic transcriptional response in yeast.

  15. Comparative study on triangular and quadrilateral meshes by a finite-volume method with a central difference scheme

    KAUST Repository

    Yu, Guojun

    2012-10-01

    In this article, comparative studies on computational accuracies and convergence rates of triangular and quadrilateral meshes are carried out in the frame work of the finite-volume method. By theoretical analysis, we conclude that the number of triangular cells needs to be 4/3 times that of quadrilateral cells to obtain similar accuracy. The conclusion is verified by a number of numerical examples. In addition, the convergence rates of the triangular meshes are found to be slower than those of the quadrilateral meshes when the same accuracy is obtained with these two mesh types. © 2012 Taylor and Francis Group, LLC.

  16. Two-Fluid Mathematical Models for Blood Flow in Stenosed Arteries: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Sankar DS

    2009-01-01

    Full Text Available The pulsatile flow of blood through stenosed arteries is analyzed by assuming the blood as a two-fluid model with the suspension of all the erythrocytes in the core region as a non-Newtonian fluid and the plasma in the peripheral layer as a Newtonian fluid. The non-Newtonian fluid in the core region of the artery is assumed as a (i Herschel-Bulkley fluid and (ii Casson fluid. Perturbation method is used to solve the resulting system of non-linear partial differential equations. Expressions for various flow quantities are obtained for the two-fluid Casson model. Expressions of the flow quantities obtained by Sankar and Lee (2006 for the two-fluid Herschel-Bulkley model are used to get the data for comparison. It is found that the plug flow velocity and velocity distribution of the two-fluid Casson model are considerably higher than those of the two-fluid Herschel-Bulkley model. It is also observed that the pressure drop, plug core radius, wall shear stress and the resistance to flow are significantly very low for the two-fluid Casson model than those of the two-fluid Herschel-Bulkley model. Hence, the two-fluid Casson model would be more useful than the two-fluid Herschel-Bulkley model to analyze the blood flow through stenosed arteries.

  17. Comparative anatomy of the arterial system of the foot in primates. 1. Macaque.

    Science.gov (United States)

    Matsumoto, S; Ikeda, A

    1990-01-01

    Using stereoscopic angiography, the entire arterial system of the foot of the macaque was analyzed. The arteria saphena, instead of the a. tibialis anterior, reaches the dorsum of the foot, and its branches supply most of the foot. The dorsal arteries are dominant as far as the metatarsal spaces of the lateral four toes. The a. metatarsea dorsalis II showed a tendency to be the single dominant artery and to give rise to even the a. digitalis communis plantaris IV through the catella plantaris distalis. This tendency was observed more clearly in other macaques species than the Japanese monkey. The perforating branch at the second proximal metatarsal space forms the arcus plantaris profundus, which is accompanied by the deep branch of the nervus plantaris lateralis. Beneath the arch, the catella plantaris proximalis is formed on the metatarsal bones among the perforating branches of the aa. metatarseae dorsales. The a. tibialis posterior forms the arcus plantaris superficialis, whose thin branches commonly enter the aa. digitales communes plantares.

  18. Comparative imaging study in ultrasound, MRI, CT, and DSA using a multimodality renal artery phantom

    Energy Technology Data Exchange (ETDEWEB)

    King, Deirdre M.; Fagan, Andrew J.; Moran, Carmel M.; Browne, Jacinta E. [Medical Ultrasound Physics and Technology Group, School of Physics, Dublin Institute of Technology, Dublin 8 (Ireland); Centre for Advanced Medical Imaging (CAMI), St James' s Hospital, Dublin 8 (Ireland); Department of Medical Physics, University of Edinburgh, Edinburgh EH16 4TJ (United Kingdom); Medical Ultrasound Physics and Technology Group, School of Physics, Dublin Institute of Technology, Dublin 8 (Ireland)

    2011-02-15

    Purpose: A range of anatomically realistic multimodality renal artery phantoms consisting of vessels with varying degrees of stenosis was developed and evaluated using four imaging techniques currently used to detect renal artery stenosis (RAS). The spatial resolution required to visualize vascular geometry and the velocity detection performance required to adequately characterize blood flow in patients suffering from RAS are currently ill-defined, with the result that no one imaging modality has emerged as a gold standard technique for screening for this disease. Methods: The phantoms, which contained a range of stenosis values (0%, 30%, 50%, 70%, and 85%), were designed for use with ultrasound, magnetic resonance imaging, x-ray computed tomography, and x-ray digital subtraction angiography. The construction materials used were optimized with respect to their ultrasonic speed of sound and attenuation coefficient, MR relaxometry (T{sub 1},T{sub 2}) properties, and Hounsfield number/x-ray attenuation coefficient, with a design capable of tolerating high-pressure pulsatile flow. Fiducial targets, incorporated into the phantoms to allow for registration of images among modalities, were chosen to minimize geometric distortions. Results: High quality distortion-free images of the phantoms with good contrast between vessel lumen, fiducial markers, and background tissue to visualize all stenoses were obtained with each modality. Quantitative assessments of the grade of stenosis revealed significant discrepancies between modalities, with each underestimating the stenosis severity for the higher-stenosed phantoms (70% and 85%) by up to 14%, with the greatest discrepancy attributable to DSA. Conclusions: The design and construction of a range of anatomically realistic renal artery phantoms containing varying degrees of stenosis is described. Images obtained using the main four diagnostic techniques used to detect RAS were free from artifacts and exhibited adequate contrast

  19. Comparative Finite Element Analysis of the Effects of Tillage Tool Geometry on Soil Disturbance and Reaction Forces

    Directory of Open Access Journals (Sweden)

    Mohamed Ahmed Elbashir

    2014-04-01

    Full Text Available In this study a comparative finite element analysis was conducted to investigate the effects of tillage tool geometry on soil disturbance and reaction forces. A nonlinear three dimensional finite element model, using ANSYS software, was developed to study the soil cutting process by trapezoidal (T1 and rectangular (T2 flat tools that inclined to the horizontal at three rake angles (R1 = 30°, R2 = 60° and R3 = 90°, therefore a total of six treatments were considered in this analysis. The soil media was assumed as elastic-perfectly plastic material with Drucker-Prager’s model. Results of this study revealed that the maximum vertical soil displaced by T1 is greater than that of T2; hence T1 disturbed the soil better than T2 . Results also showed that a significant reduction in draft force was noticed when cutting the soil with T1 in comparison to T2 . Designing the tool in the form of T1 significantly reduces the surface area of the tool; thus conserving the engineering material.

  20. Carotid artery stenting compared with endarterectomy in patients with symptomatic carotid stenosis (International Carotid Stenting Study) : an interim analysis of a randomised controlled trial

    NARCIS (Netherlands)

    Ederle, Joerg; Dobson, Joanna; Featherstone, Roland L.; Bonati, Leo H.; van der Worp, H. Bart; de Borst, Gert J.; Lo, T. Hauw; Gaines, Peter; Dorman, Paul J.; Macdonald, Sumaira; Lyrer, Philippe A.; Hendriks, Johanna M.; McCollum, Charles; Nederkoorn, Paul J.; Brown, Martin M.; Algra, A.; Bamford, J.; Beard, J.; Bland, M.; Bradbury, A. W.; Brown, M. M.; Clifton, A.; Gaines, P.; Hacke, W.; Halliday, A.; Malik, I.; Mas, J. L.; McGuire, A. J.; Sidhu, P.; Venables, G.; Bradbury, A.; Brown, M. M.; Clifton, A.; Gaines, P.; Collins, R.; Molynewc, A.; Naylor, R.; Warlow, C.; Ferro, J. M.; Thomas, D.; Bonati, L. H.; Coward, L.; Dobson, J.; Ederle, J.; Featherstone, R. F.; Tindall, H.; McCabe, D. J. H.; Wallis, A.; Brooks, M.; Chambers, B.; Chan, A.; Chu, P.; Clark, D.; Dewey, H.; Donnan, G.; Fell, G.; Hoare, M.; Molan, M.; Roberts, A.; Roberts, N.; Beiles, B.; Bladin, C.; Clifford, C.; Fell, G.; Grigg, M.; New, G.; Bell, R.; Bower, S.; Chong, W.; Holt, M.; Saunder, A.; Than, P. G.; Gett, S.; Leggett, D.; McGahan, T.; Quinn, J.; Ray, M.; Wong, A.; Woodruff, P.; Foreman, R.; Schultz, D.; Scroop, R.; Stanley, B.; Allard, B.; Atkinson, N.; Cambell, W.; Davies, S.; Field, P.; Milne, P.; Mitchell, P.; Tress, B.; Yan, B.; Beasley, A.; Dunbabin, D.; Stary, D.; Walker, S.; Cras, P.; d'Archambeau, O.; Hendriks, J. M. H.; Van Schil, P.; Bosiers, M.; Deloose, K.; van Buggenhout, E.; De Letter, J.; Devos, V.; Ghekiere, J.; Vanhooren, G.; Astarci, P.; Hammer, F.; Lacroix, V.; Peeters, A.; Verhelst, R.; DeJaegher, L.; Peeters, A.; Verbist, J.; Blair, J-F; Caron, J. L.; Daneault, N.; Giroux, M-F; Guilbert, F.; Lanthier, S.; Lebrun, L-H; Oliva, V.; Raymond, J.; Roy, D.; Soulez, G.; Weill, A.; Hill, M.; Hu, W.; Hudion, M.; Morrish, W.; Sutherland, G.; Wong, J.; Alback, A.; Harno, H.; Ijas, P.; Kaste, M.; Lepantalo, M.; Mustanoja, S.; Paananen, T.; Porras, M.; Putaala, J.; Railo, M.; Sairanen, T.; Soinne, L.; Vehmas, A.; Vikatmaa, P.; Goertler, M.; Halloul, Z.; Skalej, M.; Brennan, P.; Kelly, C.; Leahy, A.; Moroney, J.; Thornton, J.; Koelemay, M. J. W.; Nederkoorn, P. J.; Reekers, J. A. A.; Roos, Y. B. W. E. M.; Hendriks, J. M.; Koudstaal, P. J.; Pattynama, P. M. T.; van der Lugt, A.; van Dijk, L. C.; van Sambeek, M. R. H. M.; van Urk, H.; Verhagen, H. J. M.; Bruininckx, C. M. A.; de Bruijn, S. F.; Keunen, R.; Knippenberg, B.; Mosch, A.; Treurniet, F.; van Dijk, L.; van Overhagen, H.; Wever, J.; de Beer, F. C.; van den Berg, J. S. P.; van Hasselt, B. A. A. M.; Zeilstra, D. J.; Boiten, J.; van Otterloo, J. C. A. de Mol; de Vries, A. C.; Nieholt, G. J. Lycklama A.; van der Kallen, B. F. W.; Blankensteijn, J. D.; De Leeuw, F. E.; Kool, L. J. Schultze; van der Vliet, J. A.; de Borst, G. J.; de Kort, G. A. P.; Kapelle, L. J.; Lo, T. H.; Mali, W. P. Th M.; Moll, F.; van der Worp, H. Bart; Verhagen, H.; Barber, P. A.; Bourchier, R.; Hill, A.; Holden, A.; Stewart, J.; Bakke, S. J.; Krohg-Sorensen, K.; Skjelland, M.; Tennoe, B.; Bialek, P.; Biejat, Z.; Czepiel, W.; Czlonkowska, A.; Dowzenko, A.; Jedrzejewska, J.; Kobayashi, A.; Lelek, M.; Polanski, J.; Kirbis, J.; Milosevic, Z.; Zvan, B.; Blasco, J.; Chamorro, A.; Macho, J.; Obach, V.; Riambau, V.; San Roman, L.; Branera, J.; Canovas, D.; Estela, Jordi; Gimenez Gaibar, A.; Perendreu, J.; Bjorses, K.; Gottsater, A.; Ivancev, K.; Maetzsch, T.; Sonesson, B.; Berg, B.; Delle, M.; Formgren, J.; Gillgren, P.; Kall, T-B; Konrad, P.; Nyman, N.; Takolander, R.; Andersson, T.; Malmstedt, J.; Soderman, M.; Wahlgren, C.; Wahlgren, N.; Binaghi, S.; Hirt, L.; Michel, P.; Ruchat, P.; Bonati, L. H.; Engelter, S. T.; Fluri, F.; Guerke, L.; Jacob, A. L.; Kirsch, E.; Lyrer, P. A.; Radue, E-W; Stierli, P.; Wasner, M.; Wetzel, S.; Bonvin, C.; Kalangos, A.; Lovblad, K.; Murith, N.; Ruefenacht, D.; Sztajzel, R.; Higgins, N.; Kirkpatrick, P. J.; Martin, P.; Adam, D.; Bell, J.; Bradbury, A. W.; Crowe, P.; Gannon, M.; Henderson, M. J.; Sandler, D.; Shinton, R. A.; Scriven, J. M.; Wilmink, T.; D'Souza, S.; Egun, A.; Guta, R.; Punekar, S.; Seriki, D. M.; Thomson, G.; Brennan, A.; Enevoldson, T. P.; Gilling-Smith, G.; Gould, D. A.; Harris, P. L.; McWilliams, R. G.; Nasser, H-C; White, R.; Prakash, K. G.; Serracino-Inglott, F.; Subramanian, G.; Symth, J. V.; Walker, M. G.; Clarke, M.; Davis, M.; Dixit, S. A.; Dolman, P.; Dyker, A.; Ford, G.; Golkar, A.; Jackson, R.; Jayakrishnan, V.; Lambert, D.; Lees, T.; Louw, S.; Macdonald, S.; Mendelow, A. D.; Rodgers, H.; Rose, J.; Stansby, G.; Wyatt, M.; Baker, T.; Baldwin, N.; Jones, L.; Mitchell, D.; Munro, E.; Thornton, M.; Baker, D.; Davis, N.; Hamilton, G.; McCabe, D.; Platts, A.; Tibballs, J.; Beard, J.; Cleveland, T.; Dodd, D.; Gaines, P.; Lonsdale, R.; Nair, R.; Nassef, A.; Nawaz, S.; Venables, G.; Belli, A.; Clifton, A.; Cloud, G.; Halliday, A.; Markus, H.; McFarland, R.; Morgan, R.; Pereira, A.; Thompson, A.; Chataway, J.; Cheshire, N.; Gibbs, R.; Hammady, M.; Jenkins, M.; Malik, I.; Wolfe, J.; Adiseshiah, M.; Bishop, C.; Brew, S.; Brookes, J.; Brown, M. M.; Jaeger, R.; Kitchen, N.; Ashleigh, R.; Butterfield, S.; Gamble, G. E.; McCollum, C.; Nasim, A.; O'Neill, P.; Wong, J.; Edwards, R. D.; Lees, K. R.; MacKay, A. J.; Moss, J.; Rogers, P.

    2010-01-01

    Background Stents are an alternative treatment to carotid endarterectomy for symptomatic carotid stenosis, but previous trials have not established equivalent safety and efficacy. We compared the safety of carotid artery stenting with that of carotid endarterectomy. Methods The International Carotid

  1. Carotid artery stenting compared with endarterectomy in patients with symptomatic carotid stenosis (International Carotid Stenting Study): an interim analysis of a randomised controlled trial.

    LENUS (Irish Health Repository)

    Ederle, Jörg

    2010-03-20

    Stents are an alternative treatment to carotid endarterectomy for symptomatic carotid stenosis, but previous trials have not established equivalent safety and efficacy. We compared the safety of carotid artery stenting with that of carotid endarterectomy.

  2. Intra-arterial MR-angiography on an open-bore MR-scanner compared to digital-subtraction angiography of the infra-popliteal runoff in patients with peripheral arterial occlusive disease

    Energy Technology Data Exchange (ETDEWEB)

    Huegli, Rolf W. [Department of Radiology University Hospital of Basel, Petersgraben 4, 4031 Basel (Switzerland)], E-mail: rhuegli@uhbs.ch; Thalhammer, Christoph [Department of Angiology, University Hospital of Basel, Petersgraben 4, 4031 Basel (Switzerland)], E-mail: cthalhammer@uhbs.ch; Jacob, Augustinus L. [Department of Radiology University Hospital of Basel, Petersgraben 4, 4031 Basel (Switzerland)], E-mail: ajacob@uhbs.ch; Jaeger, Kurt [Department of Angiology, University Hospital of Basel, Petersgraben 4, 4031 Basel (Switzerland)], E-mail: kjaeger@uhbs.ch; Bilecen, Deniz [Department of Radiology University Hospital of Basel, Petersgraben 4, 4031 Basel (Switzerland)], E-mail: dbilecen@uhbs.ch

    2008-06-15

    Purpose: To evaluate the diagnostic value of contrast-enhanced intra-arterial 3D-MR-angiography (IA-MRA) of the infra-popliteal arteries in an open-bore magnet. Number, severity of arterial lesions, and artefacts were compared to routinely performed intra-arterial digital-subtraction angiography (IA-DSA) in patients suffering from symptomatic peripheral arterial occlusive disease (PAOD). Material and methods: Fifteen patients admitted for PAOD underwent percutaneous transluminal angioplasty (PTA) by IA-DSA. After PTA, IA-MRA of the infra-popliteal station was performed on an open-bore 1.5 T MR-scanner applying a low dose intra-arterial contrast-enhanced 3D-gradient-echo-MRA with gadopentate dimeglumine. The reading was performed by three blinded readers distinguishing moderate ({<=}50%), significant stenoses (51-99%) and vessel occlusions. Imaging artefacts were recorded and binary classified as not disturbing or compromising the observation of the arterial tree. Results: Overall IA-DSA revealed 36 moderate stenoses ({<=}50%), 38 significant stenoses (51-99%), and 10 vessel occlusions. For the detection of significant stenoses and occlusions, the overall sensitivity, specificity, positive predictive value, negative predictive value and accuracy of IA-MRA were 96%, 83%, 88%, 94% and 90%. The only observed artefact was venous overlay in four stations. The readout was not hampered in any case. Conclusion: Intra-arterial contrast-enhanced 3D-gradient-echo-MRA on an open-bore MR-scanner offers an acceptable diagnostic accuracy in diagnosing peripheral arterial occlusive disease in the infra-popliteal region and correlates well with DSA.

  3. Meta-analysis of randomized trials comparing the effectiveness of on-pump and off-pump coronary artery bypass

    Institute of Scientific and Technical Information of China (English)

    CHEN Yong-bing; SHU Jian; YANG Wen-tao; SHI Li; GUO Xu-feng; WANG Fei-ge; QIAN Yong-yue

    2012-01-01

    Background The growing enthusiasm for coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB) is emerging,but the role of off-pump coronary artery bypass (OPCAB) in clinical practice remains controversial.The purpose of this study was to assess differences in the incidences of stroke,atrial fibrillation (AF),and myocardial infarction (MI) between OPCAB and conventional coronary artery bypass grafting (CCABG) by meta-analyses of randomized clinical trials.Methods A literature search for the period before March 2010 supplemented with manual bibliographic review was performed for all Chinese or English publications in Medline,the Science Citation Index Expanded,the Cochrane Central Register of Controlled Trials (CENTRAL) and CBMdisc.A systematic overview (meta-analyses) of randomized clinical trials was conducted to evaluate the differences between OPCAB and CCABG in the incidences of stroke,AF,and MI.The meta-analysis was performed using RevMan 5 software.Results Forty-three randomized clinical trials were selected for meta-analysis after screening a total of 356 references,with 8104 patients in the OPCAB group and 8724 cases in the CCABG group.The meta-analyses of these trials showed no significant difference between OPCAB and CCABG in the incidences of stroke (odds ratio (OR)=0.80,95% confidence interval (CI)=0.52-1.22,P=0.30) and MI (OR=0.73,95%CI=0.52-1.02,P=0.06).However,we found a significantly reduced risk of AF (OR=0.65,95%CI =0.52-0.82,P=0.0002)in off-pump patients.Conclusions Our meta-analyses suggest that OPCAB reduces the risk of postoperative AF compared with CCABG,but there is no significant difference in the incidences of stroke and MI between OPCAB and CCABG.

  4. COMPARATIVE EFFICIENCY OF THE COMBINED THERAPY IN PATIENT’S WITH ARTERIAL HYPERTENSION

    Directory of Open Access Journals (Sweden)

    V. V. Shchekotov

    2014-07-01

    Full Text Available Objective — to assess influence of the combined therapy on a functional condition endothelium, the central haemodynamics and geometry of heart in patients with hypertensive disease.Subjects and methods. The volume of supervision has made 40 patients with arterial hypertension grade II hypertension, moderate — highrisk. Patients of the first group received the combined therapy lisinopril — 20 mg and hydrochlortiazid — 12.5 mg (iruzid — “Belupo”, Croatia, patients of the second group — therapy trandolapril and verapamil (tarka — “Ebbot”, Germany — 2 and 180 mg accordingly.Results. The combined therapy trandolapril and verapamil renders more expressed antihypertension effect, than lisinopril and hydrochlortiazid.Appointment of the combined therapy promoted normalization morphofunctional heart indicators: in group of tarka ejection fraction(EF has authentically increased by 4.34 % (р = 0,02, the thickness to a back wall of the left ventricle has decreased for 5.8 % (р = 0,03 in group of iruzid. Also in both groups optimization functional a condition endothelium vessels as on level desquamation endotheliocytes, a function indicator endothelium and on a level of a factor of Willebrand was marked. Authentically more expressed positive influence on endothelium tarka in comparison with iruzid has been noticed.Conclusion. At comparison of combinations fat-soluble ACE inhibitor with verapamil (tarka and water-soluble ACE inhibitor in a combination with hydrochlortiazid (iruzid the insignificant superiority of the first combination over the second for level of positive influence on endothelium of vessels has been revealed, more expressed antihypertensive effect and ability authentically to increase EF.

  5. COMPARATIVE EFFICIENCY OF THE COMBINED THERAPY IN PATIENT’S WITH ARTERIAL HYPERTENSION

    Directory of Open Access Journals (Sweden)

    V. V. Shchekotov

    2011-01-01

    Full Text Available Objective — to assess influence of the combined therapy on a functional condition endothelium, the central haemodynamics and geometry of heart in patients with hypertensive disease.Subjects and methods. The volume of supervision has made 40 patients with arterial hypertension grade II hypertension, moderate — highrisk. Patients of the first group received the combined therapy lisinopril — 20 mg and hydrochlortiazid — 12.5 mg (iruzid — “Belupo”, Croatia, patients of the second group — therapy trandolapril and verapamil (tarka — “Ebbot”, Germany — 2 and 180 mg accordingly.Results. The combined therapy trandolapril and verapamil renders more expressed antihypertension effect, than lisinopril and hydrochlortiazid.Appointment of the combined therapy promoted normalization morphofunctional heart indicators: in group of tarka ejection fraction(EF has authentically increased by 4.34 % (р = 0,02, the thickness to a back wall of the left ventricle has decreased for 5.8 % (р = 0,03 in group of iruzid. Also in both groups optimization functional a condition endothelium vessels as on level desquamation endotheliocytes, a function indicator endothelium and on a level of a factor of Willebrand was marked. Authentically more expressed positive influence on endothelium tarka in comparison with iruzid has been noticed.Conclusion. At comparison of combinations fat-soluble ACE inhibitor with verapamil (tarka and water-soluble ACE inhibitor in a combination with hydrochlortiazid (iruzid the insignificant superiority of the first combination over the second for level of positive influence on endothelium of vessels has been revealed, more expressed antihypertensive effect and ability authentically to increase EF.

  6. Assessment of the efficacy of phentolamine to prevent radial artery spasm during cardiac catheterization procedures: a randomized study comparing phentolamine vs. verapamil.

    Science.gov (United States)

    Ruiz-Salmerón, Rafael J; Mora, Ramón; Masotti, Mónica; Betriu, Amadeo

    2005-10-01

    The objective of this study was to evaluate phentolamine as radial artery spasmolytic in transradial catheterization procedures. Radial artery spasm is a relatively frequent complication during transradial approach, causing patient discomfort or even making it impossible to continue the procedure. As radial artery spasm is mediated by the stimulation of alpha-adrenoreceptors, the use of the alpha-blocker phentolamine could make sense as spasmolytic. We designed a randomized double-blind study to compare phentolamine vs. verapamil, the standard spasmolytic agent. Five hundred patients (250 in each arm) submitted to a transradial cardiac catheterization were consecutively included and randomly assigned to receive 2.5 mg of verapamil or 2.5 mg of phentolamine after sheath insertion. Both vasodilator agents induced a significant radial artery diameter increase (from 2.22 +/- 0.53 to 2.48 +/- 0.57 mm, P phentolamine). However, verapamil was more efficacious to prevent radial artery spasm (13.2% compared with 23.2% in phentolamine-treated patients; P = 0.004). Follow-up (20 +/- 18 days) evaluation of the radial artery patency by plestismography and pulse oximetry showed no differences between the two groups in the rate of radial occlusion (3.0% vs. 3.2% in verapamil and phentolamine treated patients, respectively). Phentolamine was an effective radial vasodilator agent, although it showed less ability to prevent radial artery spasm than verapamil. Radial artery occlusion rate was almost identical for both vasodilators. Thus, phentolamine could be a valid alternative to verapamil as a radial artery spasmolytic agent.

  7. Carotid artery stenting compared with endarterectomy in patients with symptomatic carotid stenosis (International Carotid Stenting Study): an interim analysis of a randomised controlled trial

    OpenAIRE

    Ederle, J; Dobson, J.; Featherstone, RL; Bonati, LH; van der Worp, HB; de Borst, GJ; lo, TH; Gaines, P.; Dorman, PJ; Macdonald, S; Lyrer, PA; Hendriks, JM; McCollum, C; Nederkoorn, PJ; Brown, MM

    2010-01-01

    Summary Background Stents are an alternative treatment to carotid endarterectomy for symptomatic carotid stenosis, but previous trials have not established equivalent safety and efficacy. We compared the safety of carotid artery stenting with that of carotid endarterectomy. Methods The International Carotid Stenting Study (ICSS) is a multicentre, international, randomised controlled trial with blinded adjudication of outcomes. Patients with recently symptomatic carotid artery stenosis were ra...

  8. A Comparative Analysis of Series And Finite Element Solutions For Flow In Multi-layer Aquifers With Contiguous Layers

    Science.gov (United States)

    Wong, S.; Craig, J. R.

    2009-05-01

    Recently, Wong S. & J.R. Craig [Computational Methods in Water Resources XVII International Conference, 2008] have developed a semi-analytic series (SAS) solution method for simulating 2D steady-state groundwater flow in multi-layer aquifers with natural unconformity. The advantages of the approach include the capability to predict groundwater flow in aquifer systems with a geometrically complex structure, i.e., layers that are contiguous but vary (sometimes dramatically) in thickness across the modelled domain. The SAS approach is unorthodox compared to numerical scheme such as finite element (FE) method when handling an aquifer basin with contiguous layers. This research attempts to compare the robustness of the SAS solution with that of the FE solution under variety of different geometric conditions, including the increasing of system aspect ratios and the inclusion of pinching layers. It was found that the SAS approach is a useful benchmarking tool and that for contiguous layers, both FE methods continue to be highly accurate at even large aspect ratios. Based on the benchmarking experiments, some rules of thumb for mesh generation in FE models of regional aquifer systems with both contiguous and discontiguous layering are identified.

  9. Coronary artery calcium score using electron beam tomography in the patients with acute obstructive coronary arterial disease : comparative study within asymptomatic high-risk group of atherosclerosis and chronic obstructive coronary arterial disease group

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Seok Jong; Choi, Byoung Wook; Choe, Kyu Ok [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

    2001-04-01

    To compare, through analysis of the coronary artery calcium (CAC) score and the risk factors for atherosclerosis, the characteristics of acute coronary syndrome between an asymptomatic high-risk group of atherosclerosis patients and a chronic coronary arterial obstructive disease(CAOD) group. The CAC scores of an asymptomatic high-risk group of atherosclerosis patients (group I, n=284), a chronic CAOD croup (group II, n=39) and an acute coronary syndrome group (group III, n=21) were measured by electron beam tomography. Forty-seven patients with CAOD from groups II and III underwent coronary angiography, and we scrutinized age, sex and risk factors including diabetes mellitus, hypertension, obesity, smoking, hypercholesterolemia and low high-density lipoproteinemia. The numbers of stenotic coronary arterial branches and degree of stenosis revealed by coronary angiography were also recorded. We determined the differences between the three groups in terms of CAC score and the risk factors, the relationship between CAC score and risk factors, and the characteristic features of each type of CAOD group. The mean CA score of group III (135.1) was not statistically different from that of group I (135.7) or group II (365.8). Among patients aged below 50, the mean CAC score of group III (127.4) was significantly higher than that of group I (6.2), (p=0.0006). The mean CAC score at the sixth decade was also significantly different between group I(81.5) and group II (266.9). The mean age of group III (54.2 years) was significantly lower than that of group I (58.1 years) (p=0.047) and of group II (60.1) (p=0.022). There was significant correlation between the number of stenotic coronary arterial branches and log(CAC +1) (p<.01). The square root of the CAC score and the maximal degree of stenosis was also well correlated (p<.01). There was no difference in the mean number of risk factors among the three groups, though the incidence of smoking in group III was significantly

  10. Comparism of Computer Based Yield Line Theory with Elastic Theory and Finite Element Methods for Solid Slabs

    Directory of Open Access Journals (Sweden)

    J.O. Akinyele

    2011-02-01

    Full Text Available The complexity and conservative nature of the Yield Line Theory and its being an upper bound theory have made many design engineers to jettison the use of the analytical method in the analysis of slabs. Before now, the method has basically been a manual or hand methodwhich some engineers did not see a need for its use since there are many computer based packages in the analysis and design of slabs and other civil engineering structures. This paper presents a computer program that has adopted the yield line theory in the analysis of solid slabs. Two rectangular slabs of the same depth but differentdimensions were investigated. The Yield Line Theory was compared with two other analytical methods namely, Finite Element Method and Elastic Theory Method. The results obtained for a two-way spanning slab showed that the yield line theory is truly conservative, butincreasing the result by 25% caused the moment obtained to be very close to the results of the other two methods. Although it was still conservative, the check for deflections showed that it is reliable and economical in terms of reinforcement provision. For a one way spanning slab the results without any increment falls in between the two other methods with the Elastic method giving a conservative results. The paper concludes that the introduction of a computer-based yield line theory program will make the analytical method acceptable to design engineers in the developing countries of the world.

  11. Aggressive lipid-lowering therapy compared with angioplasty in stable coronary artery disease

    NARCIS (Netherlands)

    Pitt, B; Waters, D; Brown, WV; van Boven, AJ; Schwartz, L; Title, LM; Eisenberg, D; Shurzinske, L; McCormick, LS

    1999-01-01

    Background Percutaneous coronary revascularization is widely used in improving symptoms and exercise performance in patients with ischemic heart disease and stable angina pectoris. In this study, we compared percutaneous coronary revascularization with lipid-lowerin Methods We studied 341 patients w

  12. Validation and absolute quantification of MR perfusion compared with CT perfusion in patients with unilateral cerebral arterial stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Fang-Ying, E-mail: fychiou@hotmail.com [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei City, Taiwan (China); Kao, Yi-Hsuan, E-mail: yhkao@ym.edu.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei City, Taiwan (China); Teng, Michael Mu Huo, E-mail: mhteng@gmail.com [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei City, Taiwan (China); School of Medicine, National Yang-Ming University, Taipei City, Taiwan (China); Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan (China); Chung, Hsiao-Wen, E-mail: chung@cc.ee.ntu.edu.tw [Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan (China); Chang, Feng-Chi, E-mail: fcchang374@gmail.com [School of Medicine, National Yang-Ming University, Taipei City, Taiwan (China); Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan (China); Cho, I-Chieh, E-mail: jessie8030@yahoo.com.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei City, Taiwan (China); Chen, Wen-Chun, E-mail: sky7408695@hotmail.com [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei City, Taiwan (China)

    2012-12-15

    Objective: The aim of the study was to assess absolute quantification of dynamic susceptibility contrast-enhanced magnetic resonance perfusion (MRP) comparing with computed tomography perfusion (CTP) in patients with unilateral stenosis. Materials and methods: We retrospectively post-processed MRP in 20 patients with unilateral occlusion or stenosis of >79% at the internal carotid artery or the middle cerebral artery (MCA). Absolute quantification of MRP was performed after applying the following techniques: cerebrospinal fluid removal, vessel removal, and automatic segmentation of brain to calculate the scaling factors to convert relative cerebral blood volume (rCBV) and relative cerebral blood flow (rCBF) values to absolute values. For comparison between MRP and CTP, we manually deposited regions of interest in bilateral MCA territories at the level containing the body of the lateral ventricle. Results: The correlation between MRP and CTP was best for mean transit time (MTT) (r = 0.83), followed by cerebral blood flow (CBF) (r = 0.52) and cerebral blood volume (CBV) (r = 0.43). There was no significant difference between CTP and MRP for CBV, CBF, and MTT on the lesion side, the contralateral side, the lesion-contralateral differences, or the lesion-to-contralateral ratios (P > 0.05). The mean differences between MRP and CTP were as follows: CBV −0.57 mL/100 g, CBF 2.50 mL/100 g/min, and MTT −0.90 s. Conclusion: Absolute quantification of MRP is possible. Using the proposed method, measured values of MRP and CTP had acceptable linear correlation and quantitative agreement.

  13. Arterial luminal curvature and fibrous-cap thickness affect critical stress conditions within atherosclerotic plaque: an in vivo MRI-based 2D finite-element study.

    Science.gov (United States)

    Teng, Zhongzhao; Sadat, Umar; Li, Zhiyong; Huang, Xueying; Zhu, Chengcheng; Young, Victoria E; Graves, Martin J; Gillard, Jonathan H

    2010-10-01

    High mechanical stress in atherosclerotic plaques at vulnerable sites, called critical stress, contributes to plaque rupture. The site of minimum fibrous cap (FC) thickness (FC(MIN)) and plaque shoulder are well-documented vulnerable sites. The inherent weakness of the FC material at the thinnest point increases the stress, making it vulnerable, and it is the big curvature of the lumen contour over FC which may result in increased plaque stress. We aimed to assess critical stresses at FC(MIN) and the maximum lumen curvature over FC (LC(MAX)) and quantify the difference to see which vulnerable site had the highest critical stress and was, therefore, at highest risk of rupture. One hundred patients underwent high resolution carotid magnetic resonance (MR) imaging. We used 352 MR slices with delineated atherosclerotic components for the simulation study. Stresses at all the integral nodes along the lumen surface were calculated using the finite-element method. FC(MIN) and LC(MAX) were identified, and critical stresses at these sites were assessed and compared. Critical stress at FC(MIN) was significantly lower than that at LC(MAX) (median: 121.55 kPa; inter quartile range (IQR) = [60.70-180.32] kPa vs. 150.80 kPa; IQR = [91.39-235.75] kPa, p LC(MAX) only was used, then 112 out of 352 would be underestimated. Stress analysis at FC(MIN) and LC(MAX) should be used for a refined mechanical risk assessment of atherosclerotic plaques, since material failure at either site may result in rupture.

  14. Predicting long-term independency in activities of daily living after middle cerebral artery stroke: does information from MRI have added predictive value compared with clinical information?

    NARCIS (Netherlands)

    Schiemanck, S.K.; Kwakkel, G.; Post, M.W.; Kappelle, L.J.; Prevo, A.J.

    2006-01-01

    BACKGROUND AND PURPOSE: To investigate whether neuroimaging information has added predictive value compared with clinical information for independency in activities of daily living (ADL) 1 year after stroke. METHODS: Seventy-five first-ever middle cerebral artery stroke survivors were evaluated in l

  15. Cardiovascular events in acute coronary syndrome patients with peripheral arterial disease treated with ticagrelor compared to clopidogrel: Data from the PLATO trials

    DEFF Research Database (Denmark)

    Patel, Manesh R.; Becker, Richard C.; Wojdyla, Daniel M.;

    Abstract 14299: Cardiovascular Events in Acute Coronary Syndrome Patients With Peripheral Arterial Disease Treated With Ticagrelor Compared to Clopidogrel: Data From the PLATO Trial Manesh R Patel1; Richard C Becker1; Daniel M Wojdyla2; Håkan Emanuelsson3; William Hiatt4; Jay Horrow5; Steen Husted6...

  16. Arterial spin-labeling MR imaging in moyamoya disease compared with clinical assessments and other MR imaging finings

    Energy Technology Data Exchange (ETDEWEB)

    Noguchi, Tomoyuki, E-mail: tnogucci@radiol.med.kyushu-u.ac.jp [Department of Radiology, Faculty of Medicine, Saga University, 5-1-1, Nabeshima, Saga 849-8501 (Japan); Kawashima, Masatou [Department of Neurosurgery, Faculty of Medicine, Saga University, 5-1-1, Nabeshima, Saga 849-8501 (Japan); Nishihara, Masashi; Hirai, Tetsuyoshi [Department of Radiology, Faculty of Medicine, Saga University, 5-1-1, Nabeshima, Saga 849-8501 (Japan); Matsushima, Toshio [Department of Neurosurgery, Faculty of Medicine, Saga University, 5-1-1, Nabeshima, Saga 849-8501 (Japan); Irie, Hiroyuki [Department of Radiology, Faculty of Medicine, Saga University, 5-1-1, Nabeshima, Saga 849-8501 (Japan)

    2013-12-01

    Purpose: Our purpose was to identify the causal factors for the perfusion distribution obtained with ASL-MRI by comparing ASL-MRI with clinical information and other MRI findings in moyamoya disease. Methods: Seventy-one patients with moyamoya disease underwent ASL-MRI and other MRI, including fluid-attenuated inversion recovery imaging (FLAIR) and three-dimensional time-of-flight magnetic resonance angiography (MRA) on 3.0-Tesla MRI system. Cerebral blood flow (CBF) values (ASL values) for the cerebral hemispheres (142 sides) were measured on CBF maps generated by ASL-MRI. Relationships between the ASL values and the following 9 factors were assessed: sex, family history, revascularization surgery, age at MR exam, age at onset, the steno-occlusive severity on MRA (MRA score), degree of basal collaterals, degree of leptomeningeal high signal intensity seen on FLAIR, and size of ischemic or hemorrhagic cerebrovascular accident lesion (CVA score). Results: Patients with a family history had significantly higher ASL values than those without such a history. There were significant negative correlations between ASL values and age at MR exam, MRA score, and CVA score. Conclusions: ASL-MRI may have cause-and-effect or mutual associations with family history, current patient age, size of CVA lesion, and intracranial arterial steno-occlusive severity in Moyamoya disease.

  17. INTRAVASCULAR ULTRASOUND EVALUATING CORONARY STENTS FOR PATIENTS WITH CORONARY ARTERY DISEASE: COMPARED OLD WITH NEW MULTILINK STENTS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Objective.It was suggested that coronary stent design and coating may affect stent performance and hence induce varying degrees of thrombogenesis and neointimal hyperplasia.The purpose of this study is to compare the 6 month follow up results between old and new Multilink stents with the method of intravascular ultrasound (IVUS) imaging.Methods.We have performed old (n=40) and new (n=35) Multilink stent implantations on 75 patients with coronary artery disease.Coronary angiography was performed before,immediately after,and 6 months after the in stent procedure respectively.Six month follow up IVUS imaging was performed and analyzed off line.Results.Minimal lumen cross sectional area (CSA) of new Multilink stents was significantly larger than that of old Multilink stents (P=0.0053).Mean stent lumen area of new Multilink stents was significantly larger than that of old Multilink stents (P=0.040).Similarly,minimal lumen diameter (MLD) of new Multilink stents was larger than that of old Multilink stents (P= 0.011).Old Multilink stents had a higher percentage of plaque area than new Multilink stents.Conclusion.The new Multilink stent is obviously superior to old Multilink stents,in particular,in the stent MLD and lumen CSA- - major determinants of the restenosis.

  18. Effect of aliskiren on arterial stiffness, compared with ramipril in patients with mild to moderate essential hypertension

    Institute of Scientific and Technical Information of China (English)

    GUO Jian-qiang; WANG Hong-yi; SUN Ning-ling

    2013-01-01

    Background Aliskiren is a novel blood pressure-lowering agent acting as an oral direct renin inhibitor.The aim of this study was to assess the effect of aliskiren on arterial stiffness,compared with that of ramipril in mild to moderate essential hypertensive patients.Methods Following a two week placebo run-in period,patients with a mean sitting diastolic blood pressure (ms-DBP) >95 and <110 mmHg (1 mmHg=0.133 kPa),and a mean sitting systolic blood pressure (ms-SBP) <180 mmHg were randomly allocated to treatment with aliskiren (150 mg/d,n=20) or ramipril (5 mg/d,n=20) for eight weeks.Blood pressure,plasma renin activity,and the brachial-ankle pulse wave velocity (ba-PWV) were measured before and after eight weeks of treatment.Results Eight weeks of treatment significantly decreased systolic blood pressure and diastolic blood pressure in both the aliskiren group and ramipril group.The hypotensive effect did not differ between the two groups.Plasma renin activity decreased after aliskiren treatment and increased after ramipril treatment.There was no significant difference in baseline ba-PWV between the aliskiren and ramipril groups (P=-0.892).The ba-PWV was significantly reduced in both the aliskiren group (1535 (1405-1666) vs.1464 (1360-1506) cm/s) (P <0.01) and the ramipril group (1544 (1433-1673) vs.1447 (1327-1549) cm/s) (P <0.01).No statistically significant difference was found in the decline of ba-PWV between the two groups (P=0.766).Conclusions The current study revealed that aliskiren (150 mg/d) could ameliorate arterial stiffness and its effect was similar to ramipril (5 mg/d) in mild to moderate hypertensive patients,indicating that in addition to lowering blood pressure,aliskiren had beneficial effect on vascular protection.

  19. Pulmonary Artery Catheter (PAC Accuracy and Efficacy Compared with Flow Probe and Transcutaneous Doppler (USCOM: An Ovine Cardiac Output Validation

    Directory of Open Access Journals (Sweden)

    Robert A. Phillips

    2012-01-01

    Full Text Available Background. The pulmonary artery catheter (PAC is an accepted clinical method of measuring cardiac output (CO despite no prior validation. The ultrasonic cardiac output monitor (USCOM is a noninvasive alternative to PAC using Doppler ultrasound (CW. We compared PAC and USCOM CO measurements against a gold standard, the aortic flow probe (FP, in sheep at varying outputs. Methods. Ten conscious sheep, with implanted FPs, had measurements of CO by FP, USCOM, and PAC, at rest and during intervention with inotropes and vasopressors. Results. CO measurements by FP, PAC, and USCOM were 4.0±1.2 L/min, 4.8±1.5 L/min, and 4.0±1.4 L/min, respectively, (=280, range 1.9 L/min to 11.7 L/min. Percentage bias and precision between FP and PAC, and FP and USCOM was −17 and 47%, and 1 and 36%, respectively. PAC under-measured Dobutamine-induced CO changes by 20% (relative 66% compared with FP, while USCOM measures varied from FP by 3% (relative 10%. PAC reliably detected −30% but not +40% CO changes, as measured by receiver operating characteristic area under the curve (AUC, while USCOM reliably detected ±5% changes in CO (AUC>0.70. Conclusions. PAC demonstrated poor accuracy and sensitivity as a measure of CO. USCOM provided equivalent measurements to FP across a sixfold range of outputs, reliably detecting ±5% changes.

  20. A comparative study of experimental and finite element analysis on submillimeter flaws by laser and ultrasonic excited thermography

    Science.gov (United States)

    Zhang, Hai; Fernandes, Henrique; Yu, Lingyao; Hassler, Ulf; Genest, Marc; Robitaille, François; Joncas, Simon; Sheng, Yunlong; Maldague, Xavier

    2016-05-01

    Stitching is used to reduce dry-core and reinforce T-joint structure. However, it might cause new types of flaws, especially submillimeter flaws. In this paper, new approaches including micro-VT, lock-in micro-LLT and micro-LST based on both lock-in and pulse methods are used to detect submillimeter flaws in stitched CFRP. A comparison of laser excitation thermography and micro-VT on micro-porosities is conducted. Micro-CT is used to validate the infrared results. Then, a finite element analysis (FEA) is performed. The geometrical model needed for finite element discretization was developed from micro-CT measurements. The model is validated for the experimental results. Finally a comprehensive experimental and simulation comparison of micro-LLT and micro-LST based on both lock-in and pulse methods is conducted.

  1. Comparative analysis of early and middle outcomes of the arterial switch operation in children with complete transposition of the great arteries with ventricular septal defect and severe pulmonary artery hypertension

    Institute of Scientific and Technical Information of China (English)

    LIU Cheng-hu; SU Jun-wu; LI Zhi-qiang; FAN Xiang-ming; CHEN Yan; HE Yan; LIU Ying-long

    2013-01-01

    Background The best age for the arterial switch operation (ASO) in complete transposition of great arteries with ventricular septal defect is usually considered to be within six months.This is because of severe pulmonary arterial hypertension and pulmonary arterial obstructive pathological changes.There are few reports on ASO surgery in children older than three years old.Methods We studied 41 children,including 24 males and 17 females,from January 2010 to December 2011.They were divided into three groups by operation age; 15 patients were <1 year old,13 were 1-3 years old,and 13 were >3 years old.Associated cardiac abnormalities included patent ductus arteriosus in six cases,atrial septal defect in five cases,and mitral regurgitation in two cases.All the patients had echocardiography before the operation.Seventeen patients underwent a coronary computed tomography examination and five patients underwent right heart catheterization.All ASO surgeries were performed under inhalation anesthesia and hypothermic cardiopulmonary bypass.Results Three operative deaths occurred.Two were in the <1 year old group,who died from severe postoperative low cardiac output.The other was two years old and died of postoperative multiple organ failure.There was no significant difference in postoperative mortality and the recent mid-term survival rate among the three groups.Thirty-eight cases were followed up for an average of 11.2 months,ranging 6-20 months.One seven years old patient died of acute diarrhea and electrolyte disturbance arrhythmia caused by food poisoning.Three patients more than three years old still had residual pulmonary arterial hypertension.Conclusion Children older than three years old can still undergo the ASO procedure,but residual pulmonary hypertension is present.

  2. Comparative reactivity of the myeloperoxidase-derived oxidants hypochlorous acid and hypothiocyanous acid with human coronary artery endothelial cells.

    Science.gov (United States)

    Lloyd, Mitchell M; Grima, Michael A; Rayner, Benjamin S; Hadfield, Katrina A; Davies, Michael J; Hawkins, Clare L

    2013-12-01

    In the immune response, hypohalous acids are generated by activated leukocytes via the release of myeloperoxidase and the formation of H2O2. Although these oxidants have important bactericidal properties, they have also been implicated in causing tissue damage in inflammatory diseases, including atherosclerosis. Hypochlorous acid (HOCl) and hypothiocyanous acid (HOSCN) are the major oxidants formed by myeloperoxidase under physiological conditions, with the ratio of these oxidants dependent on diet and smoking status. HOCl is highly reactive and causes marked cellular damage, but few data are available on the effects of HOSCN on mammalian cells. In this study, we have compared the actions of HOCl and HOSCN on human coronary artery endothelial cells (HCAEC). HOCl reacts rapidly with the cells, resulting in extensive cell death by both apoptosis and necrosis, with necrosis dominating at higher oxidant doses. In contrast, HOSCN is consumed more slowly, with cell death occurring only by apoptosis. Exposure of HCAEC to HOCl and HOSCN induces changes in mitochondrial membrane permeability, which, in the case of HOSCN, is associated with mitochondrial release of proapoptotic factors, including cytochrome c, apoptosis-inducing factor, and endonuclease G. With each oxidant, apoptosis appears to be caspase-independent, with the inactivation of caspases 3/7 observed, and pretreatment of the cells with the caspase inhibitor Z-VAD-fmk having no effect on the extent of cell death. Loss of cellular thiols, depletion of glutathione, and the inactivation of thiol-dependent enzymes, including glyceraldehyde-3-phosphate dehydrogenase, were seen with both oxidants, though to a much greater extent with HOCl. The ability of myeloperoxidase-derived oxidants to induce endothelial cell apoptosis may contribute to the formation of unstable lesions in atherosclerosis. The results with HOSCN may be particularly significant for smokers, who have elevated plasma levels of SCN(-), the precursor

  3. Comparative Evaluation of the Implant Made of Yttrium-partially Stabilized Zirconia and Pure Titanium on Stress Distribution by Anisotropic Finite Element Method

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The purpose of this research is to analyze and compare stress distribution patterns around dental implant made of pure titanium and yttrium-partial stabilized zirconia (YPSZ) in anisotropic versus isotropic finite element method under vertical and oblique loads. Although the properties of implant and crown were changed,similar stress distribution and close stress level were observed in two different implant finite element models. The stress values were a little lower in the YPSZ model. In the bone, anisotropy increased the stress values by 30%-70% in the isotropic cases. The YPSZ implant could be more valuable choice for implant because of esthetic requirement. Anisotropy had subtle, yet significant effects on the stress level.

  4. Cranial arterial pattern of the Sri Lankan spotted chevrotain, Moschiola memmina, and comparative basicranial osteology of the Tragulidae.

    Science.gov (United States)

    O'Brien, Haley D

    2015-01-01

    The cranial arterial pattern of artiodactyls deviates significantly from the typical mammalian pattern. One of the most striking atypical features is the rete mirabile epidurale: a subdural arterial meshwork that functionally and anatomically replaces the arteria carotis interna. This meshwork facilitates an exceptional ability to cool the brain, and was thought to be present in all artiodactyls. Recent research, however, has found that species of mouse deer (Artiodactyla: Tragulidae) endemic to the Malay Archipelago possess a complete a. carotis interna instead of a rete mirabile epidurale. As tragulids are the sister group to pecoran ruminants, the lack of a rete mirabile epidurale in these species raises intriguing evolutionary questions about the origin and nature of artiodactyl thermoregulatory cranial vasculature. In this study, cranial arterial patterns are documented for the remaining species within the Tragulidae. Radiopaque latex vascular injection, computed tomography (CT-scanning), and digital 3-dimensional anatomical reconstruction are used to image the cranial arteries of a Sri Lankan spotted chevrotain, Moschiola meminna. Sites of hard and soft tissue interaction were identified, and these osteological correlates were then sought in nine skulls representative of the remaining tragulid species. Both hard and soft tissue surveys confirm that the presence of an a. carotis interna is the common condition for tragulids. Moreover, the use of a 3-D, radiographic anatomical imaging technique enabled identification of a carotico-maxillary anastomosis that may have implications for the evolution of the artiodactyl rete mirabile epidurale.

  5. COMPARATIVE EVALUATION OF CENTRAL VENOUS VERSUS ARTERIAL BLOOD SAMPLE FOR REPETITIVE MEASUREMENTS IN CRITICALLY ILL PATIENTS ADMITTED IN INTENSIVE CARE UNIT

    Directory of Open Access Journals (Sweden)

    Rukhsana

    2015-08-01

    Full Text Available OBJECTIVES: The purpose of present study was to evaluate the reliability of central venous blood gas monitoring as an alternative to arterial blood gas monitoring and to assess that the central venous catheter is convenient and reliable source of blood for repetitive measurement of pH bicarbonate and PCO2 in critically ill patients admitted in surgical intensive care unit (SICU. METHODS: We took one hundred patients who required ABG analysis between 20 - 60 years of age. The cases were divided in four groups which constituted major admissions in SICU in one year. Out of one hundred patients for the study there were 19 Poisoning patients, 15 Trauma patients, 40 Major abdominal surgery patients, 26 Hypovolemic shock patients and others. Central Venous blood drawn within 5 min of an ABG measurement and the samples analyzed immediately on automated ABG analyzer were compared. RESULTS: Bland Altman plots demonstrated a high degree of agreement between the two corresponding sets of measurements of arterial and venous blood with coefficient of correlation 0.979 for pH. The coefficient of correlation was highly positive i.e. 0.926 for PCO 2 and 0.955 for HCO 3 - which is statistically significant. There was also positive correlation for saturation between arterial and venous blood i.e. 0.57 with clinically acceptable difference and is statistically significant. The difference in pO 2 measurements was however higher with correlation coefficient of 0.259 although the arterial saturation and finger oximetry reveals a good degree of agreement with clinically acceptable bias. CONCLUSION: Venous blood gas (VBG analysis clearly does not replace ABG analysis in determining exact pO 2 status and arterial puncture may still be required for invasive arterial BP monitoring. With positive correlation and regression plots obtained, venous samples can be used as an alternative to arterial samples depending on the significant positive correlation values obtained for

  6. Finite Element Method Modeling of Sensible Heat Thermal Energy Storage with Innovative Concretes and Comparative Analysis with Literature Benchmarks

    Directory of Open Access Journals (Sweden)

    Claudio Ferone

    2014-08-01

    Full Text Available Efficient systems for high performance buildings are required to improve the integration of renewable energy sources and to reduce primary energy consumption from fossil fuels. This paper is focused on sensible heat thermal energy storage (SHTES systems using solid media and numerical simulation of their transient behavior using the finite element method (FEM. Unlike other papers in the literature, the numerical model and simulation approach has simultaneously taken into consideration various aspects: thermal properties at high temperature, the actual geometry of the repeated storage element and the actual storage cycle adopted. High-performance thermal storage materials from the literatures have been tested and used here as reference benchmarks. Other materials tested are lightweight concretes with recycled aggregates and a geopolymer concrete. Their thermal properties have been measured and used as inputs in the numerical model to preliminarily evaluate their application in thermal storage. The analysis carried out can also be used to optimize the storage system, in terms of thermal properties required to the storage material. The results showed a significant influence of the thermal properties on the performances of the storage elements. Simulation results have provided information for further scale-up from a single differential storage element to the entire module as a function of material thermal properties.

  7. Comparative Investigation on Modal analysis of LM25 Aluminium alloy with other Aluminim alloys using Finite element analysis software

    Science.gov (United States)

    Arunkumar, S.; Baskaralal, V. P. M.; Muthuraman, V.

    2017-03-01

    The rudimentary steps of the modal analysis and simulation are carried out. The modal analysis is carried out on the different Aluminum Alloys cantilever beam. The cantilever beam is designed in the graphical environment of the ANSYS. The cantilever beam was fine-tuned on one end with all degree of liberation on this end were taken, beam cannot move and rotate. Mode shapes and natural frequencies are premeditated in platforms ANSYS with arithmetical formulation of the direct solver including the block Lanczos method. Aluminum alloys are widely utilized in much application due to their estimable weight to vigor property. Many examination works have been distributed out to make developments the mechanical properties of aluminum alloys. The composition of alloying elements plays a consequential role in deciding the properties of an alloy. In this study a numerical analysis implement i.e., finite element analysis (FEA) is utilized. The work obtainable in this paper is aimed at the study of effect of modal analysis of different aluminum alloys. The modeling and analysis is carried out utilizing ANSYS FEA software. A modal analysis is carried out to understand the modes of frequency demeanor of the material considered. The modal analysis play a vital role in the design of components subjected to high vibration.

  8. [Upper extremity arterial diseases].

    Science.gov (United States)

    Becker, F

    2007-02-01

    Compared to lower limb arterial diseases, upper limb arterial diseases look rare, heterogeneous with various etiologies and a rather vague clinical picture, but with a negligible risk of amputation. Almost all types of arterial diseases can be present in the upper limb, but the anatomical and hemodynamic conditions particular to the upper limb often confuse the issue. Thus, atherosclerosis affects mainly the subclavian artery in its proximal segment where the potential of collateral pathway is high making the symptomatic forms not very frequent whereas the prevalence of subclavian artery stenosis or occlusion is relatively high. The clinical examination and the etiologies are discussed according to the clinical, anatomical and hemodynamic context.

  9. Comparative study of on-pump and off-pump coronary bypass surgery in patients with triple-vessel coronary artery disease

    Institute of Scientific and Technical Information of China (English)

    陈鑫; 徐明; 史宏伟; 穆心伟; 陈振强; 邱志兵

    2004-01-01

    Background Studies on selected patients undergoing off-pump versus on-pump coronary artery bypass surgery have produced inconsistent results, especially in patients with multiple coronary artery disease. This study compared the clinical results of on-pump and off-pump coronary bypass surgery in patients with triple-vessel disease.Methods A total of 300 consecutive isolated, multiple coronary artery bypass grafting (CABG) patients were assigned to the off-pump coronary artery bypass (OPCAB, n=150) or CABG with cardiopulmonary bypass (CCABG, n=150) groups. There were no significant differences regarding degree of angina, history of myocardial infarction or diabetes, and presence of left main coronary artery disease between the two groups. Ejection fraction in the OPCAB group before surgery was lower than in the CCABG group (P<0.01). In addition, more patients had a history of stroke and abnormal renal function preoperatively in the OPCAB group(P< 0.01). In OPCAB patients, single deep pericardial stay suture with a sling snared down was used to expose the target vessels, along with a stabilizer and a coronary shunt. A Medi-Stim Butterfly Flowmeter was used to measure blood flow through grafts in both groups.Results No OPCAB patient was converted to the CCABG group. The average numbers of distal anastomoses and the indexes of completeness of revascularization (ICR) were similar in both groups. Postoperative respiratory support time and the volumes of chest tube drainage and of blood transfusions were less in the OPCAB group than in the CCABG group (both P<0.01). The postoperative incidences of pulmonary dysfunction and renal insufficiency were lower in the OPCAB group than in the CCABG group (both P<0.05). There were no significant differences between the two groups in mortality and other causes of morbidity (periopetative myocardial infarction, stroke, atrial fibrillation). Conclusions OPCAB can be applied to patients with triple-vessel coronary artery disease and can

  10. Effect of root canal treatment procedures with a novel rotary nickel titanium instrument (TRUShape) on stress in mandibular molars: a comparative finite element analysis.

    Science.gov (United States)

    Bonessio, Noemi; Arias, Ana; Lomiento, Guiseppe; Peters, Ove A

    2017-01-01

    The aim of this study was to investigate and compare, via finite element analysis (FEA), the effects of endodontic access and canal preparation on stress distribution under functional loading of a mandibular molar treated with novel (TRUShape) and conventional (Vortex) rotary root canal preparation instruments. Identical plastic mandibular molars with natural anatomy had all 4 canals shaped with either TRUShape or a conventional rotary, Vortex (#20 and #30, both by Dentsply Tulsa Dental). Finite element analysis was used to evaluate stress distribution in untreated and treated models. Micro-computed tomography (MCT) of the extracted teeth shaped in vitro was used to inform the FEA model regarding the geometry of root canals and external surfaces. Modeling the intact periodontal support and cancellous/cortical bone was based on anatomical data. Profiles of average and maximum von Mises stresses in dentin of the four treated conditions under functional loading were compared to the untreated model. This comparison was performed for each tooth model with and without root canal obturation and composite restoration. On average, the dentin sections with the most changes after preparation were located in the access cavity, with average stress increase up to +5.7, +8.5, +8.9, and +10.2 % for the TRUShape #20, Vortex #20, TRUShape #30 and Vortex #30, respectively, relative to the untreated model. Within the root canal system, the average stress differences were smaller than finite element analysis, preparation of the access cavity resulted in increased von Mises stresses under functional occlusal load. The limited (up to 0.7 %) retained radicular dentin in the TRUShape versus the Vortex cavity proved effective in reducing masticatory stresses. The bonded restoration modeled in this study only partially counterbalance the combined effects of access cavity and root canal preparation.

  11. Effect of androgen suppression compared with androgen receptor blockade on arterial stiffness in men with prostate cancer.

    Science.gov (United States)

    Dockery, Frances; Bulpitt, Christopher J; Agarwal, Sanjiv; Vernon, Clare; Rajkumar, Chakravarthi

    2009-01-01

    Endogenous testosterone and estradiol are thought to be cardio-protective in men. We wanted to determine the effects of 2 different anti-androgen therapies on arterial stiffness as one suppresses (goserelin--a gonadotrophin-releasing hormone analog) while the other increases (bicalutamide--an androgen receptor blocker) both testosterone and estradiol. We conducted a randomized trial on 43 men (mean age, 71.2 +/- 6.2 years) with localized prostate cancer. They received either goserelin or bicalutamide for 24 weeks. Carotid-femoral (C-F) and carotid-radial (C-R) pulse wave velocities (PWVs) were measured. Twenty age- and disease-matched men with prostate cancer on no active treatment were studied in a similar manner. After 12 weeks of goserelin, radial artery PWV increased significantly from baseline and a nonsignificant increase was observed in femoral PWV (change from baseline radial: +1.4 m/s, P = .002, femoral: +0.9 m/s, P = .127) Both PWV measures increased significantly with bicalutamide (change from baseline radial: +0.8, femoral: +0.9 m/s, P change from baseline radial: +1.7, femoral: +1.3 m/s, P change from baseline radial: +0.4, femoral: +0.4 m/s, P not significant [NS]); however, comparison of changes between the 2 drugs were not significantly different at either 12 or 24 weeks (P >or= .967 at 12 weeks and P >or= .07 at 24 weeks). The untreated men studied in parallel showed no changes at 12 or 24 weeks in either PWV measure. Anti-androgen treatment in men might increase large artery stiffness, an adverse cardiovascular risk factor; however, the effect was not maintained with testosterone receptor blockade, in the longer term, but tended to be sustained with suppression therapy. This could relate to the different sex hormone effects of the 2 therapies.

  12. A Markov model to compare the long-term effect of aspirin, clopidogrel and clopidogrel plus aspirin on prevention of recurrent ischemic stroke due to intracranial artery stenosis

    Directory of Open Access Journals (Sweden)

    Jinqiu Yang

    2014-01-01

    Full Text Available Background: Given the importance of intracranial stenosis as a cause of recurrent ischemic stroke and the lack of evidence supporting a clear choice for prevention of recurrent ischemic events, a computer simulation model for prognostic prediction could be used to improve decision making. Aims: The aim of the following study is to compare the long-term effect of aspirin, clopidogrel and clopidogrel plus aspirin for prevention of recurrent stroke due to atherosclerotic intracranial artery stenosis. Setting and Design: The cohort consisted of 206 patients from 2006 to 2011. Materials and Methods: A two-state Markov model was used to predict the prognosis of patients with stroke or transient ischemic attack (TIA caused by angiographically verified 50-99% stenosis of a major intracranial artery to receive aspirin, clopidogrel, or dual therapy. Statistical Analysis: Two tests were used: Pearson Chi-square test or Fisher′s exact test (for percentages and Kruskal Wallis test (for rank order data. Results: In the 10-year Markov cohort analysis, 36.24% of patients who were treated with clopidogrel plus aspirin developed to recurrent stroke while the probability for patients in the aspirin group and clopidogrel group was 42.60% and 48.39% respectively. Patients with clopidogrel plus aspirin had the highest quality-adjusted life years, followed by aspirin and clopidogrel. Conclusion: To prevent recurrent stroke in patients with intracranial artery stenosis, especially in those patients with a history of TIA or coronary artery disease, medical therapy with clopidogrel plus aspirin should be considered in preference to aspirin alone.

  13. An antithrombotic fucoidan, unlike heparin, does not prolong bleeding time in a murine arterial thrombosis model: a comparative study of Undaria pinnatifida sporophylls and Fucus vesiculosus.

    Science.gov (United States)

    Min, Soon-Ki; Kwon, Oh-Choon; Lee, Sub; Park, Ki-Hyuk; Kim, Jong-Ki

    2012-05-01

    The antithrombotic activities and bleeding effects of selected fucoidans (source from either Undaria pinnatifida sporophylls or from Fucus vesiculosus) have been compared with heparin in the ferric chloride-induced arterial thrombus mouse model. Thrombosis was induced by applying 5% ferric chloride for 3 min on the carotid artery region of Balb/c mouse. Five minutes prior to thrombus induction, mice were infused through the tail vein with either saline (control) or polysaccharides. Either fucoidan or heparin was dosed at 0.1, 1.25, 2.5, 5.0, 10, 25, or 50 mg/kg intravenously (i.v.) The carotid blood flow was monitored until more than 60 min post-thrombus induction. Mouse tail transection bleeding time was measured up to 60 min after making a cut in the mouse tail. Both antithrombotic and bleeding effects were observed in a dose-dependent manner for both fucoidans and heparin. Thrombus formation was totally (reflected by Doppler flow meter) inhibited at either 5 or 50 mg/kg of unfractionated Undaria fucoidan or a low-molecular-weight Undaria fucoidan fraction, respectively, without prolonging the time-to-stop bleeding compared with the control (p Fucus fucoidan at 25 mg/kg where the time-to-stop bleeding was still significantly prolonged, by as much as 8 ± 1.7 min (p < 0.02). In contrast the heparin-treated group showed total inhibition of thrombus formation even at a small dose of 0.8 mg/kg (400 IU) at which bleeding continued until 60 min. In conclusion algal fucoidans are highly antithrombotic without potential haemorrhagic effects compared with heparin in the arterial thrombus model, but this property differs from algal species to species, and from the molecular structure of fucoidans.

  14. Finite Automation

    OpenAIRE

    2005-01-01

    This self-paced narrated tutorial covers the following about Finite Automata: Uses, Examples, Alphabet, strings, concatenation, powers of an alphabet, Languages (automata and formal languages), Deterministic finite automata (DFA) SW4600 Automata, Formal Specification and Run-time Verification

  15. Finite-element simulation of the performance of a superconducting meander structure shielding for a cryogenic current comparator

    Science.gov (United States)

    De Gersem, H.; Marsic, N.; Müller, W. F. O.; Kurian, F.; Sieber, T.; Schwickert, M.

    2016-12-01

    The ferrite core and measuring coil of a cryogenic current comparator have to be shielded against external magnetic fields by a compact, efficient meander structure made of superconducting niobium. A design with minimized material and production costs is only feasible when a highly accurate magnetic field simulator is available. 3D field models become prohibitively large. The cylindrical symmetry of the devices motivates to develop a quasi-3D field solver, exploiting the symmetry while still capable of representing 3D field distributions.

  16. The morphogenesis of the arteries of the pelvic extremity. A comparative study of mammals with special reference to the tree shrew Tupaia belangeri (Tupaiidae, Scandentia, Mammalia).

    Science.gov (United States)

    Funke, C; Kuhn, H J

    1998-01-01

    The ontogeny of the arteries of the pelvic extremity of Tupaia belangeri was investigated by light microscopy on the basis of serial sections of 30 embryos, dating from day 17 to day 42 post-copulation. In Tupaia, the gestational period takes approximately 43 days. Additionally, a 3-D reconstruction of the pelvic region and the right leg of a 22-day embryo was prepared. The arteries of an adult Tupaia were studied on the basis of a corrosion cast. The results were compared with the ontogeny of the arterial system of other mammals. In the 17-day embryo, the anlage of the pelvic extremity is penetrated by a capillary plexus. In the 18-day embryo, the a. ischiadica reaches the pelvic limb bud, representing the primary axial artery. On day 19, its r. perforans tarsi extends from the plantar to the dorsal aspect of the foot plate. The a. ischiadica is the main artery of the leg until the stage of the 22-day embryo. Afterwards, the peripheral arteries supplied by it are taken over by the a. iliaca externa and its extension, the a. femoralis. The a. iliaca externa springs from the a. iliaca communis in the 19-day embryo. From day 21 to day 22, the capillary plexus, which is nourished by the a. femoralis, closely approaches the a. ischiadica, and finally, a connecting branch joins the a. ischiadica. The a. ischiadica is then reduced to the a. glutea caudalis, and the aa. femoralis, poplitea profunda (at the cranial aspect of the m. popliteus), and interossea become the main arteries of the pelvic extremity. The a. poplitea superficialis, lying at the caudal aspect of the m. popliteus, and its continuation in the crural region, the a. peronea, develop until the 25-day embryo. The a. peronea gives rise to an r. perforans which penetrates the membrana interossea towards the dorsum of the foot. As a result of a shift of the origin of the a. iliaca externa in the proximal direction, the length of the a. iliaca communis gradually decreases until, on day 24, the a. iliaca externa

  17. Comparative effect of grape seed extract (Vitis vinifera and ascorbic acid in oxidative stress induced by on-pump coronary artery bypass surgery

    Directory of Open Access Journals (Sweden)

    Naser Safaei

    2017-01-01

    Full Text Available Background: This study aimed to test the beneficial effect of grape seed extract (GSE (Vitis vinifera and Vitamin C in oxidative stress and reperfusion injury induced by cardiopulmonary bypass (CPB in coronary artery bypass surgery. Patients and Methods: In this randomized trial, 87 patients undergoing elective and isolated coronary bypass surgery included. The patients were randomly assigned into three groups (n = 29 each: (1 Control group with no treatment, (2 GSE group who received the extract 24 h before operation, 100 mg every 6 h, orally, (3 Vitamin C group who received 25 mg/kg Vitamin C through CPB during surgery. Blood samples were taken from coronary sinus at (T1 just before aortic cross clamp; (T2 just before starting controlled aortic root reperfusion; and (T3 10 min after root reperfusion. Some clinical parameters and biochemical markers were compared among the groups. Results: There were significant differences in tracheal intubation times, sinus rhythm return, and left ventricular function between treatment groups compared with control (P 0.05 in all cases. Conclusions: In our patients, GSE and Vitamin C had antioxidative effects and reduced deleterious effects of CPB during coronary artery bypass grafting surgery.

  18. Comparative Effect of Grape Seed Extract (Vitis Vinifera) and Ascorbic Acid in Oxidative Stress Induced by On-pump Coronary Artery Bypass Surgery

    Science.gov (United States)

    Safaei, Naser; Babaei, Hossein; Azarfarin, Rasoul; Jodati, Ahmad-Reza; Yaghoubi, Alireza; Sheikhalizadeh, Mohammad-Ali

    2017-01-01

    Background: This study aimed to test the beneficial effect of grape seed extract (GSE) (Vitis vinifera) and Vitamin C in oxidative stress and reperfusion injury induced by cardiopulmonary bypass (CPB) in coronary artery bypass surgery. Patients and Methods: In this randomized trial, 87 patients undergoing elective and isolated coronary bypass surgery included. The patients were randomly assigned into three groups (n = 29 each): (1) Control group with no treatment, (2) GSE group who received the extract 24 h before operation, 100 mg every 6 h, orally, (3) Vitamin C group who received 25 mg/kg Vitamin C through CPB during surgery. Blood samples were taken from coronary sinus at (T1) just before aortic cross clamp; (T2) just before starting controlled aortic root reperfusion; and (T3) 10 min after root reperfusion. Some clinical parameters and biochemical markers were compared among the groups. Results: There were significant differences in tracheal intubation times, sinus rhythm return, and left ventricular function between treatment groups compared with control (P Vitamin C groups at T2 and T3 times. In reperfusion period, malondialdehyde level was increased in control group; however, it was significantly lower for the grape seed group (P = 0.04). The differences in the mean levels of superoxide dismutase and glutathione peroxidase among the three groups were not significant (P > 0.05 in all cases). Conclusions: In our patients, GSE and Vitamin C had antioxidative effects and reduced deleterious effects of CPB during coronary artery bypass grafting surgery. PMID:28074795

  19. Differential Short-Term Repeated Forearm Hyperaemic Reactivity in Coronary Artery Disease Patients Compared to Healthy Low Risk Participants

    Directory of Open Access Journals (Sweden)

    Simon L. Bacon

    2012-01-01

    Full Text Available The hyperaemic response of the forearm is a widely used technique to assess the vascular reactivity. Little is known about the short-term reproducibility and the possible exhaustion of this response in normal or diseased states. As such, the current study was conducted to assess this phenomenon using a unique nuclear medicine- (NM- based technique. 19 patients with coronary artery disease (CAD undergoing NM exercise stress tests and 15 low risk (LR participants completed 2 reactive hyperaemia tests, using a SPECT-based technique, separated by 15  min. Analyses revealed that CAD patients had lower hyperaemic responses than LR participants (P<.001, and that there was a significant group × time interaction (P<.005, such that LR participants showed a larger decrease in the reactivity (5.2±0.4 to 3.6±0.4 than the CAD patients (2.9±0.3 to 2.6±0.3. These results suggest that there is a variability, due to disease states, in the reproducibility of the hypaeremic reactivity. This needs to be taken into account in short-term repeated measure studies.

  20. A multi-center, comparative, phase 3 study to determine the efficacy of gadofosveset-enhanced magnetic resonance angiography for evaluation of renal artery disease

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, Robert [St. Boniface General Hospital, Winnipeg, Manitoba (Canada); Vymazal, Josef [Hospital Na Homolce, Prague (Czech Republic); Martinez-Lopez, Manuel [Hospital Medica Sur, Mexico City (Mexico); Neuwirth, Jiri [Faculty Hospital Motol, Prague (Czech Republic); Salgado, Perla [American British Cowdray Medical Center, Mexico City (Mexico); Beregi, Jean-Paul [Hopital Cardiologique, Lille (France); Peduto, Anthony [Westmead Hospital, Westmead New South Wales (Australia); Pena-Almaguer, Erasmo de la [Christus-Muguerza Medical Center, Monterrey, Nuevo Leon (Mexico); Slater, Greg J. [Greenslopes Private Hospital, Greenslopes, Queensland (Australia); Shamsi, Kohkan [Berlex Laboratories, Montville, NJ (United States); Parsons, Edward C. [EPIX Pharmaceuticals, Inc., Lexington, MA (United States)], E-mail: eparsons@epixpharma.com

    2008-02-15

    Purpose: To determine prospectively the safety and efficacy of the blood-pool contrast agent gadofosveset trisodium in renal artery magnetic resonance angiography (MRA). Materials and methods: Gadofosveset (0.03 mmol/kg) was administered to adult patients with known or suspected renal arterial disease in a multi-center phase 3 single dose study. The drug binds reversibly to albumin, prolonging the blood residence time, and allowing collection of images in the first-pass and steady-state phases. The combination of these images was compared to non-contrast MRA, using catheter X-ray angiography (XRA) as the standard of reference (SOR). All MRA images were collected at 1.5 T in one imaging session for direct comparison, and XRA within 30 days. Sensitivity, specificity, and accuracy for diagnosing significant disease (stenosis {>=}50%) were calculated for MRA using three independent blinded readers. Patient safety was monitored for 72-96 h. Results: A total of 145 patients at 18 centers were enrolled and received gadofosveset; the 127 with complete efficacy data entered the primary efficacy analysis. Gadofosveset-enhanced MRA led to significant improvement (p < 0.01) in sensitivity (+25%, +26%, +42%), specificity (+23%, +25%, +29%), and accuracy (+23%, +28%, +29%) over non-enhanced MRA for the three readers. The rate of uninterpretable examinations decreased from 30% to less than 2%. There were no serious adverse events, and the most common adverse events were nausea, pruritis, and headache (8% each). No significant trends in clinical chemistry parameters, nor significant changes in serum creatinine, were found following administration of gadofosveset. Conclusion: In patients with known or suspected renal arterial disease, multi-phase gadofosveset-enhanced MRA significantly improves sensitivity, specificity, and accuracy versus non-enhanced MRA. Gadofosveset was safe and well tolerated in this patient population.

  1. Arterial microcalcification in atherosclerotic patients with and without chronic kidney disease: a comparative high-resolution scanning X-ray diffraction analysis.

    Science.gov (United States)

    Fischer, Dagmar-Christiane; Behets, Geert J; Hakenberg, Oliver W; Voigt, Mathias; Vervaet, Benjamin A; Robijn, Stef; Kundt, Günther; Schareck, Wolfgang; D'Haese, Patrick C; Haffner, Dieter

    2012-06-01

    Vascular calcification, albeit heterogeneous in terms of biological and physicochemical properties, has been associated with ageing, lifestyle, diabetes, and chronic kidney disease (CKD). It is unknown whether or not moderately impaired renal function (CKD stages 2-4) affects the physiochemical composition and/or the formation of magnesium-containing tricalcium phosphate ([Ca,Mg](3)[PO(4)](2), whitlockite) in arterial microcalcification. Therefore, a high-resolution scanning X-ray diffraction analysis (European Synchrotron Radiation Facility, Grenoble, France) utilizing histological sections of paraffin-embedded arterial specimens derived from atherosclerotic patients with normal renal function (n = 15) and CKD (stages 2-4, n = 13) was performed. This approach allowed us to spatially assess the contribution of calcium phosphate (apatite) and whitlockite to arterial microcalcification. Per group, the number of samples (13 vs. 12) with sufficient signal intensity and total lengths of regions (201 vs. 232 μm) giving rise to diffractograms ("informative regions") were comparable. Summarizing all informative regions per group into one composite sample revealed calcium phosphate/apatite as the leading mineral phase in CKD patients, whereas in patients with normal renal function the relative contribution of whitlockite and calcium phosphate/apatite was on the same order of magnitude (CKD, calcium phosphate/apatite 157 μm, whitlockite 38.7 μm; non-CKD, calcium phosphate/apatite 79.0 μm, whitlockite 94.1 μm; each p < 0.05). Our results, although based on a limited number of samples, indicate that chronic impairment of renal function affects local magnesium homeostasis and thus contributes to the physicochemical composition of microcalcification in atherosclerotic patients.

  2. Comparative effects of percutaneous coronary intervention for infarct-related artery only or for both infarct-and non-infarct-related arteries in patients with ST-elevation myocardial infarction and multi-vessel disease

    Institute of Scientific and Technical Information of China (English)

    HAN Ya-ling; WANG Bin; WANG Xiao-zeng; LI Yi; WANG Shou-li; JING Quan-min; WANG Geng; MA Ying-yan; LUAN Bo

    2008-01-01

    Background Rapid recanalization of infarct-related artery (IRA) has become the major target during primary percutaneous coronary intervention (PCI) for patients with ST-elevation myocardial infarction (MI),but strategy for treatment of non-IRA lesions in this setting remains unclear.This study aimed to compare long-term effects between PCI for IRA only and that for both IRA and non-IRA in ST-elevation MI patients with multi-vessel disease.Methods A total of 242 eligible patients with ST-elevation MI and at least two diseased coronary arteries (luminal narrowing≥70%) undergoing primary PCI were included.Of them,149 patients underwent primary PCI for IRA only (group 1),and 93 received primary PCI for IRA followed by elective PCI for non-IRA 7 to 15 days after acute myocardial infarction (AMI) (group 2).Drug-eluting stents (DESs) were deployed in more than 90% of the patients.Results The two groups did not differ with respect to baseline clinical and angiographic characteristics.No significant differences were observed in 12-month clinical follow-up results regarding major adverse cardiac events (11.5% vs 15.1%,P>0.05) and target lesion revascularization (8.1% vs 7.6%,P>0.05) between the two groups.However,patients in group 1 had higher rates of recurrent angina (10.1% vs 2.1%,P<0.05) and depressed left ventricular ejection fraction evaluated by echocardiography (0.56±0.22 vs 0.63±0.25,P <0.05).Conclusion With the use of DESs,complete revascularization with elective PCI for non-IRA after primary PCI may exert a beneficial effect on long-term symptomatology and left ventricular function in patients with ST-elevation MI and multi-vessel disease.

  3. A comparative clinical study of dexmedetomidine versus placebo to attenuate hemodynamic response to endotracheal intubation in patients undergoing off pump coronary arterial bypass grafting

    Directory of Open Access Journals (Sweden)

    Soniya R Sulhyan

    2014-01-01

    Full Text Available Context: Direct laryngoscopy and endotracheal intubation are the most stressful periods during induction of anesthesia. These events can lead to hypertension, tachycardia, arrhythmias and myocardial ischaemia. Aims: (1 To evaluate the haemodynamic response to laryngoscopy and endotracheal intubation with a single preinduction infusion of dexmedetomidine (DEX 1 μg/kg over a 10 min period, (2 To assess the incidence of side effects, that is, rebound hypertension, bradycardia and hypotension etc., associated with the use of DEX. Settings and Design: This was a prospective, double-blind, parallel group randomized clinical trial of DEX (1 μg/kg before anesthetic induction to study the attenuation of hemodynamic response to endotracheal intubation in 60 adult patients undergoing elective off pump coronary arterial bypass grafting. Materials and Methods: Patients were randomly allocated to receive either DEX (DEX group, n = 30 or 0.9% normal saline (PLA group, n = 30. Hemodynamic variables were recorded at baseline (Abbreviated as TB, after completion of drug infusion (Abbreviated as TC, 3 min after induction and immediately before intubation (T0, at the 1 st (T1, 3 rd (T3 and 5 th (T5 min after intubation. Statistical Analysis Used: The data are presented as mean ± standard deviation. Demographic data were analysed by Student′s t-test between the two groups. Analysis of variance for repeated measures f-test was used to analyze changes over time. A P < 0.05 was considered as significant and P < 0.01 or 0.001 was considered as highly significant. Results: All the hemodynamic variables were comparable in both groups at baseline. Heart rate values were statistically significantly lower in the DEX group at TC and highly statistically significantly lower at T1, T3 and T5 values. Systolic blood pressure values were statistically significantly lower in the DEX group at T0 and highly statistically significantly lower at T1, T3 and T5. Diastolic blood

  4. Comparative Study of Compensatory Liver Regeneration in a Rat Model: Portal Vein Ligation Only versus Sequential Ligation of the Portal Vein and Hepatic Artery

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Soo Young [Dept. of Pathology, Dongnam Institute of Radiological and Medical Sciences, Busan (Korea, Republic of); Jeon, Gyeong Sik [Dept. of Radiology, CHA Bundang Medical Center, College of Medicine, CHA University, Seongnam (Korea, Republic of); Lee, Byung Mo [Dept. of Surgery, Seoul Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of)

    2013-04-15

    To compare the volume change and the regenerative capacity between portal vein ligation (embolization) (PVL) and heterochronous PVL with hepatic artery ligation (HAL) in a rodent model. The animals were separated into three groups: group I, ligation of the left lateral and median portal vein branches; group II, completion of PVL, followed by ligation of the same branches of the hepatic artery after 48 h; control group, laparotomy without ligation was performed. Five rats from each group were sacrificed on 1, 3, 5, and 7 days after the operation. Volume change measurement, liver function tests and immunohistochemical analysis were performed. The volume of the nonligated lobe between groups I and II was not significantly different by day 5 and day 7. Mean alanine aminotransferase and total bilirubin levels were significantly higher in group II, while the albumin level was higher in group I. Both c-kit- and MIB-5-positive cells used in the activity detection of regeneration were more prevalent in group I on day 1, 3, and 5, with statistical significance. There was no operation related mortality. PVL alone is safe and effective in compensatory liver regeneration. Performing both PVL and HAL does not confer any additional benefits.

  5. A randomized trial comparing the effect of weight loss and exercise training on insulin sensitivity and glucose metabolism in coronary artery disease

    DEFF Research Database (Denmark)

    Pedersen, Lene Rørholm; Olsen, Rasmus Huan; Jürs, Anders

    2015-01-01

    AIM: The majority of patients with coronary artery disease (CAD) exhibit abnormal glucose metabolism, which is associated with mortality even at non-diabetic glucose levels. This trial aims to compare the effects of a considerable weight loss and exercise with limited weight loss on glucose...... followed by 2-4 weeks' weight maintenance diet. Glucose tolerance, insulin action, β-cell function and suppression of lipolysis were assessed using a 3-h oral glucose tolerance test. ISI-composite and ISI-HOMA (=1/HOMA-IR) were calculated as surrogate measures of whole-body and hepatic insulin sensitivity......, respectively. Magnetic resonance imaging estimated abdominal adipose tissue. Twenty-six (74%) AIT and 29 (83%) LED participants completed intervention per protocol. LED increased ISI-composite by 55% and ISI-HOMA by 70% (p0.7) revealing a significant...

  6. Diagnostic performance of cardiac imaging methods to diagnose ischaemia-causing coronary artery disease when directly compared with fractional flow reserve as a reference standard

    DEFF Research Database (Denmark)

    Danad, Ibrahim; Szymonifka, Jackie; Twisk, Jos W R

    2016-01-01

    ), and cardiac magnetic resonance (MRI) imaging when directly compared with an FFR reference standard. METHOD AND RESULTS: PubMed and Web of Knowledge were searched for investigations published between 1 January 2002 and 28 February 2015. Studies performing FFR in at least 75% of coronary vessels......AIMS: The aim of this study was to determine the diagnostic performance of single-photon emission computed tomography (SPECT), stress echocardiography (SE), invasive coronary angiography (ICA), coronary computed tomography angiography (CCTA), fractional flow reserve (FFR) derived from CCTA (FFRCT...... for the diagnosis of ischaemic coronary artery disease (CAD) were included. Twenty-three articles reporting on 3788 patients and 5323 vessels were identified. Meta-analysis was performed for pooled sensitivity, specificity, likelihood ratios (LR), diagnostic odds ratio, and summary receiver operating characteristic...

  7. A comparative study of simple methods to quantify cerebral blood flow with acetazolamide challenge by using iodine-123-IMP SPECT with one-point arterial sampling

    Energy Technology Data Exchange (ETDEWEB)

    Ohkubo, Masaki [Niigata Univ. (Japan). School of Health Sciences; Odano, Ikuo

    2000-04-01

    The aim of this study was to compare the accuracy of simplified methods for quantifying rCBF with acetazolamide challenge by using {sup 123}I-N-isopropyl-p-iodoamphetamine (IMP) and SPECT with one-point arterial sampling. After acetazolamide administration we quantified rCBF in 12 subjects by the following three methods: (a) the modified microsphere method, (b) the IMP-autoradiographic (ARG) method based on a two-compartment one-parameter model, and (c) the simplified method based on a two-compartment two-parameter model (functional IMP method). The accuracy of these methods was validated by comparing rCBF values with those obtained by the standard method: the super-early microsphere method with continuous withdrawal of arterial blood. On analyzing rCBF in each flow range (0-0.25, 0.25-0.5, 0.5-0.75 and more than 0.75 ml/g/min), rCBF values obtained by both methods (a) and (c) showed significant correlations (p<0.01) with those obtained by the standard method in every range, but rCBF values obtained by method (b) did not significantly correlated in the high flow range (0.5-0.75 and more than 0.75 ml/g/min). Method (c) was found to be the most accurate, even though it needs two serial SPECT scans. When requiring one SPECT scan, method (a) was considered to be superior to method (b) because of its accuracy, especially in high flow regions loaded with acetazolamide. (author)

  8. Efficacy and safety of radiofrequency ablation combined with transcatheter arterial chemoembolization for hepatocellular carcinomas compared with radiofrequency ablation alone: A time to event meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xin; Hu, Yanan; Ren, Mudan; Lu, Xin Lan; Lu, Gui Fang; He, Shui Xiang [Dept. of Gastroenterology, First Affiliated Hospital of Xi' an Jiaotong University, Xi' an (China)

    2016-02-15

    To compare the efficacy and safety of combined radiofrequency ablation (RFA) and transcatheter arterial chemoembolization (TACE) with RFA alone for hepatocellular carcinomas (HCC). Randomized controlled trial (RCT) studies that compared the clinical or oncologic outcomes of combination therapy of TACE and RFA versus RFA for the treatment of HCC were identified through literature searches of electronic databases (Pubmed, Embase, Cochrane Library, China Biology Medicine disc, China National Knowledge Infrastructure, and Google Scholar). Hazard ratios (HRs) or odds ratios (ORs) with their corresponding 95% confidence interval (CI) were combined as the effective value to assess the summary effects. The strength of evidence was rated by the Grading of Recommendations Assessment, Development, and Evaluation system. Six RCTs with 534 patients were eligible for inclusion in this meta-analysis. The meta-analysis showed that the combination of TACE and RFA is associated with a significantly longer overall survival (HR = 0.62, 95% CI: 0.49-0.78, p < 0.001) and recurrence-free survival (HR = 0.55, 95% CI: 0.40-0.76, p < 0.001) in contrast with RFA monotherapy. The seemingly higher incidence of major complications in the combination group compared with RFA group did not reach statistical significance (OR = 1.17, 95% CI: 0.39-3.55, p = 0.78). In patients with HCC, the combination of TACE and RFA is associated with significantly higher overall survival and recurrence-free survival, as compared with RFA monotherapy, without significant difference in major complications.

  9. Cardiac output measurement by bioimpedance and noninvasive pulse contour analysis compared with the continuous pulmonary artery thermodilution technique

    NARCIS (Netherlands)

    Maass, Saskia W. M. C.; Roekaerts, Paul M. H. J.; Lance, Marcus D.

    2014-01-01

    Objective: The aim of the present study was to compare 2 noninvasive cardiac output measurement methods with the continuous cardiac output thermodilution (CCO-TD) method. Design: A single-center prospective design. Setting: A university hospital. Participants: Fifty-three consecutive patients schedu

  10. Comparative study of graft flow between on-pump and off-pump coronary bypass surgery for patients with multivessel coronary artery disease

    Institute of Scientific and Technical Information of China (English)

    Xin Chen; Ming Xu; Zhibing Qiu; Yinshuo Jiang; Liming Wang; Liqiong Xiao

    2006-01-01

    Objective: To Comparatively study grafts flow between on-pump and off-pump coronary bypass surgery for patients with triple coronary artery disease. Methods: The grafts flow was studied in 100 patients of OPCAB and compared with100 cases of CCABG by means of Medi-Stim Butterfly Flowmeter measurement intraoperatively. Results: The mean number of the distal anastomosis was 3.78+ 1.11 in CCABG group, and 3.83 + 0.93 in OPCAB group. The index of completeness of revascularization in CCABG group was 1.01 + 0.08, and 1.10+ 0.09 in OPCAB group. The flow of grafts was satisfied in all patients. The PI values were all under 5. There was no significant difference in the mean graft flow and PI value between two groups.Conclusion: OPCAB can provide the same grafts flow and similar completeness of revascularization when compared with CCABG which indicates the similar anastomosis quality of grafts in OPCAB and CCABG groups.

  11. Numerical computation of transonic flows by finite-element and finite-difference methods

    Science.gov (United States)

    Hafez, M. M.; Wellford, L. C.; Merkle, C. L.; Murman, E. M.

    1978-01-01

    Studies on applications of the finite element approach to transonic flow calculations are reported. Different discretization techniques of the differential equations and boundary conditions are compared. Finite element analogs of Murman's mixed type finite difference operators for small disturbance formulations were constructed and the time dependent approach (using finite differences in time and finite elements in space) was examined.

  12. [Comparative effects of pindolol and atenolol on blood pressure and lipids in mild to moderate arterial hypertension].

    Science.gov (United States)

    Herpin, D; Guillard, O; Piriou, A; Amiel, A; Boutaud, P; Ciber, M A; Demange, J

    1988-01-01

    Twenty-one patients with mild or moderate hypertension were randomised to receive either Atenolol 100 mg (N = 10) or Pindolol 15 mg (N = 11) in a once daily dosage over a two month period. The effects of these two betablockers on the blood pressure and plasma lipid profile were studied. Special attention was paid to the methodology: obese patients (30% over theoretical weight derived from the Lorenz formula) and those with pre-treatment triglyceride levels higher than 1.82 mmol/l were excluded because of the well documented biological instability of such patients. The selected patients were given placebo for two weeks. At the end of the placebo period those subjects whose body weight, total cholesterol, apolipoproteins or triglycerides had varied by more than 10%, 15% and 30% respectively, were also excluded from the study. At the end of the 60 days active treatment period, a comparable fall in the blood pressure was observed in both groups and there was no significant difference in the biological parameters as compared with pre-treatment values. In addition, the cardiovascular risk, evaluated by the B/A1 apolipoprotein ratio, increased in only one patient in the group receiving Atenolol and one patient receiving Pindolol.

  13. Comparing Alterations of Blood Glucose Level in type II Diabetic Patients Taking Metformin and Withhold of Metformin on the Morning of Coronary Artery Bypass Graft Surgery

    Directory of Open Access Journals (Sweden)

    M. Tarbiat

    2016-07-01

    Full Text Available Introduction & Objective: In the context effect of metformin in patients with acute coronary syndrome, available evidence supports cardiac effect. Yet, there is doubt about continuation or discontinuation of metformin before major surgery. The aim of the present study is to determine the efficacy of continuing metformin in plasma glucose, renal function index, arterial PH in type II diabetic patients after coronary artery bypass graft surgery. Materials & Methods: In this clinical-experimental study, 90 type II diabetic patients with ASA class II admitted for CABG surgery in Hamadan Ekbatan Hospital were enrolled in the study in 2014 and were randomly assigned to two groups , one group treated with insulin and continued metformin and the other group treated with insulin and discontinued metformin.In the beginning indicators such as age, sex, body mass index (BMI were compared which were not significantly different in the two groups. Then, other parameters such as blood glucose, BUN, Cr, arterial blood PH, cardiac arrhythmia and need for inotrope were compared. Used inotropes in this study included dopamine, dobutamine, epinephrine, norepinephrine, milrinon to achieve systolic blood presser pressure over 100mmHg. Results: Average plasma BUN after surgery and one day after surgery in the group who discontinued metformin significantly were higher compared with the metformin group, but no differences were observed in average plasma BUN in the 2nd and 3rd days after surgery in the two groups. During 3 days after surgery, average plasma creatinine was significantly lower in metformin group compared to non- metformin group. Although there was no difference between the two groups in pH parameter before surgery but in the metformin group, average pH was lower than non-metformin group after surgery. Before and 3 days after surgery mean blood glucose level was not significantly different between the two groups. During surgery, average need for inotrope in

  14. Oxygenation and release of inflammatory mediators after off-pump compared with after on-pump coronary artery bypass surgery

    DEFF Research Database (Denmark)

    Rasmussen, B.S.; Laugesen, Helle; Sollid, J.

    2007-01-01

    the use of CPB (OPCAB) would affect post-operative oxygenation and release of inflammatory mediators less compared with CABG. Methods: Low-risk patients scheduled for elective coronary revascularization were randomly assigned to one of two groups (CABG, n = 17 or OPCAB, n = 18). Two parameters...... of oxygenation, shunt (%) and ventilation-perfusions mismatch, described as ΔPO2 (kPa), were estimated for up to 5 days post-operatively. Systemic release of interleukin (IL)-6, -8 and -10, C-reactive protein (CRP) and neutrophils were measured in peripheral blood samples for up to 3 days post......-operatively. The lungs participation in the cytokine response was evaluated from mixed venous blood samples taken within the first 16 h post-operatively. Results: OPCAB was followed by a higher shunt (P = 0.047), with no difference (P = 0.47) in the deterioration of ΔPO2 between the groups. OPCAB was followed...

  15. Comparison of an Additional Transdermal Fentanyl Patch Compared to Intravenous NSAID and Opioid Analgesics within 24 Hours of an Uterine Artery Embolization for Myoma and Adenomyosis

    Energy Technology Data Exchange (ETDEWEB)

    Song, Suk Yun; Kang, Byung Chul; Rho, Kyung Min [Dept. of Radiology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul (Korea, Republic of)

    2011-05-15

    To evaluate the effectiveness of an additional transdermal fentanyl patch compared to intravenous analgesics in pain control during the 24-hour period following uterine artery embolization (UAE) for myoma and adenomyosis. Between September 2009 and August 2010, 42 patients underwent UAE for myoma or adenomyosis. Of these, 21 received an intravenous opioid (pethidine) and a nonsteroidal anti-inflammatory drug (group A), and 21 received an additional transdermal fentanyl patch (group B). Pain perception levels were established verbally on a 0-10 scale during the 24-hour period following UAE. Differences in pain trends, mean dose of intravenous pethidine, and adverse effects were compared between the two groups. Pain perception was most severe at 6 hours after UAE and the mean pain level of group B at that time was 6.3 {+-} 0.7, which was significantly lower than that of group A, 8.2 {+-} 0.7 (p<0.05). The mean dose of intravenous pethidine was 114.3 {+-} 59.5 mg in group A and 90.5 {+-} 49.0 mg in group B, while the incidence of nausea was 67% in group A and 77% in group B. In both cases, the differences were not significantly different (p>0.05), and no evidence of respiratory distress was demonstrated. The addition of a transdermal fentanyl patch to intravenous analgesics is effective in reducing post-embolization pain during the 24-hour period after UAE.

  16. A comparative study of perfusion CT and 99mTc-Hmpao spect measurement to assess cerebrovascular reserve capacity in patients with internal carotid artery occlusion

    Directory of Open Access Journals (Sweden)

    Eicker S

    2011-11-01

    Full Text Available Abstract Background and purpose Patients with internal carotid artery (ICA occlusion can demonstrate impaired cerebral vascular reserve (CVR. The detection of CVR using single photon emission CT (SPECT is nowadays widely accepted as a predictor in the diagnostic pathway in patients considered for cerebral revascularization. Recently perfusion CT (PCT gained widely acceptance in stroke imaging The present study was aimed at comparing the results of perfusion CT (PCT and 99mTc-HMPAO SPECT with acetazolamide challenge in patients with ICA occlusion. Methods 13 patients were included in the prospective evaluation. Both PCT and 99mTc-HMPAO SPECT were performed before and after the administration of acetazolamide. In detail, regional cerebral blood flow (rCBF, regional cerebral blood volume (rCBV, adapted time to peak (Tmax and mean transit times (MTT were compared with SPECT data. Results 99mTc-HMPAO SPECT demonstrated an impairment of CVR in six patients. A preserved CVR was present in seven patients. All patients with impaired CVR proven by SPECT had a delayed MTT (mean +2.98 s and a delayed Tmax (mean + 5.9 s, (both p Conclusion The prospective study demonstrated a highly significant correlation of perfusion parameters as' detected by 99mTc-HMPAO SPECT and the Tmax as detected by PCT in patients with ICA occlusion. Therefore this easy-to-perform technique seems to be an adequate method for the evaluation of cerebral perfusion in patients with ICA occlusion.

  17. Drugs and lifestyle for the treatment and prevention of coronary artery disease: comparative analysis of the scientific basis.

    Science.gov (United States)

    Luz, P L da; Nishiyama, M; Chagas, A C P

    2011-10-01

    In this article, we compare two strategies for atherosclerosis treatment: drugs and healthy lifestyle. Statins are the principal drugs used for the treatment of atherosclerosis. Several secondary prevention studies have demonstrated that statins can significantly reduce cardiovascular events including coronary death, the need for surgical revascularization, stroke, total mortality, as well as fatal and non-fatal myocardial infarction. These results were observed in both men and women, the elderly, smokers and non-smokers, diabetics and hypertensives. Primary prevention studies yielded similar results, although total mortality was not affected. Statins also induce atheroma regression and do not cause cancer. However, many unresolved issues remain, such as partial risk reduction, costs, several potential side effects, and long-term use by young patients. Statins act mainly as lipid-lowering drugs but pleiotropic actions are also present. Healthy lifestyle, on the other hand, is effective and inexpensive and has no harmful effects. Five items are associated with lower cardiac risk: non-smoking, BMI ≤25, regular exercise (30 min/day), healthy diet (fruits, vegetables, low-saturated fat, and 5-30 g alcohol/day). Nevertheless, there are difficulties in implementing these measures both at the individual and population levels. Changes in behavior require multidisciplinary care, including medical, nutritional, and psychological counseling. Participation of the entire society is required for such implementation, i.e., universities, schools, media, government, and medical societies. Although these efforts represent a major challenge, such a task must be faced in order to halt the atherosclerosis epidemic that threatens the world.

  18. Finite element modelling versus classic beam theory: comparing methods for stress estimation in a morphologically diverse sample of vertebrate long bones.

    Science.gov (United States)

    Brassey, Charlotte A; Margetts, Lee; Kitchener, Andrew C; Withers, Philip J; Manning, Phillip L; Sellers, William I

    2013-02-01

    Classic beam theory is frequently used in biomechanics to model the stress behaviour of vertebrate long bones, particularly when creating intraspecific scaling models. Although methodologically straightforward, classic beam theory requires complex irregular bones to be approximated as slender beams, and the errors associated with simplifying complex organic structures to such an extent are unknown. Alternative approaches, such as finite element analysis (FEA), while much more time-consuming to perform, require no such assumptions. This study compares the results obtained using classic beam theory with those from FEA to quantify the beam theory errors and to provide recommendations about when a full FEA is essential for reasonable biomechanical predictions. High-resolution computed tomographic scans of eight vertebrate long bones were used to calculate diaphyseal stress owing to various loading regimes. Under compression, FEA values of minimum principal stress (σ(min)) were on average 142 per cent (±28% s.e.) larger than those predicted by beam theory, with deviation between the two models correlated to shaft curvature (two-tailed p = 0.03, r(2) = 0.56). Under bending, FEA values of maximum principal stress (σ(max)) and beam theory values differed on average by 12 per cent (±4% s.e.), with deviation between the models significantly correlated to cross-sectional asymmetry at midshaft (two-tailed p = 0.02, r(2) = 0.62). In torsion, assuming maximum stress values occurred at the location of minimum cortical thickness brought beam theory and FEA values closest in line, and in this case FEA values of τ(torsion) were on average 14 per cent (±5% s.e.) higher than beam theory. Therefore, FEA is the preferred modelling solution when estimates of absolute diaphyseal stress are required, although values calculated by beam theory for bending may be acceptable in some situations.

  19. Acute arterial occlusion - kidney

    Science.gov (United States)

    Acute renal arterial thrombosis; Renal artery embolism; Acute renal artery occlusion; Embolism - renal artery ... kidney can often result in permanent kidney failure. Acute arterial occlusion of the renal artery can occur after injury or trauma to ...

  20. Sensitivity of 3D gradient recalled echo susceptibility-weighted imaging technique compared to computed tomography angiography for detection of middle cerebral artery thrombus in acute stroke

    Directory of Open Access Journals (Sweden)

    Amit Agarwal

    2014-11-01

    Full Text Available We aimed at comparing the sensitivity of magnetic resonance (MR susceptibility-weighted imaging (SWI with computed tomography angiography (CTA in the detection of middle cerebral artery (MCA thrombus in acute stroke. Seventy-nine patients with acute MCA stroke was selected using our search engine software; only the ones showing restricted diffusion in the MCA territory on diffusion-weighted images were included. We finally selected 35 patients who had done both MRI (including SWI and CTA. Twenty random subjects with completely normal MRI (including SWI exam were selected as control. Two neuroradiologists (blinded to the presence or absence of stroke reviewed the SW images and then compared the findings with CT angiogram (in patients with stroke. The number of MCA segments showing thrombus in each patient was tabulated to estimate the thrombus burden. Thrombus was detected on SWI in one or more MCA segments in 30 out of 35 patients, on the first review. Of the 30, SWI showed thrombus in more than one MCA segments in 7 patients. CTA depicted branch occlusion in 31 cases. Thrombus was seen on both SWI and CTA in 28 patients. Thrombus was noted in two patients on SWI only, with no corresponding abnormality seen on CTA. Two patients with acute MCA showed no vascular occlusion or thrombus on either CTA or SWI. Only two case of false-positive thrombus was reported in normal control subjects. Susceptibility-weighted images had sensitivity and specificity of 86% and 90% respectively, with positive predictive value 94%. Sensitivity was 86% for SWI, compared with 89% for CTA, and this difference was statistically insignificant (P>0.05. Of all the positive cases on CTA (31 corresponding thrombus was seen on SWI in 90% of subjects (28 of 31. Susceptibility-weighted imaging has high sensitivity for detection of thrombus in acute MCA stroke. Moreover, SWI is a powerful technique for estimation of thrombus burden, which can be challenging on CTA.

  1. Comparing coronary artery calcium and thoracic aorta calcium for prediction of all-cause mortality and cardiovascular events on low-dose non-gated computed tomography in a high-risk population of heavy smokers.

    NARCIS (Netherlands)

    Jacobs, P.C.; Prokop, M.; Graaf, Y. van der; Gondrie, M.J.; Janssen, K.J.; Koning, H.J. de; Isgum, I.; Klaveren, R.J.J. van; Oudkerk, M.; Ginneken, B. van; Mali, W.P.Th.

    2010-01-01

    BACKGROUND: Coronary artery calcium (CAC) and thoracic aorta calcium (TAC) can be detected simultaneously on low-dose, non-gated computed tomography (CT) scans. CAC has been shown to predict cardiovascular (CVD) and coronary (CHD) events. A comparable association between TAC and CVD events has yet t

  2. Comparing coronary artery calcium and thoracic aorta calcium for prediction of all-cause mortality and cardiovascular events on low-dose non-gated computed tomography in a high-risk population of heavy smokers

    NARCIS (Netherlands)

    Jacobs, Peter C.; Prokop, Mathias; van der Graaf, Yolanda; Gondrie, Martijn J.; Janssen, Kristel J.; de Koning, Harry J.; Isgum, Ivana; van Klaveren, Rob J.; Oudkerk, Matthijs; van Ginneken, Bram; Mali, Willem P.

    2010-01-01

    Background: Coronary artery calcium (CAC) and thoracic aorta calcium (TAC) can be detected simultaneously on low-dose, non-gated computed tomography (CT) scans. CAC has been shown to predict cardiovascular (CVD) and coronary (CHD) events. A comparable association between TAC and CVD events has yet t

  3. Pulsatile compared with nonpulsatile perfusion using a centrifugal pump for cardiopulmonary bypass during coronary artery bypass grafting. Effects on systemic haemodynamics, oxygenation, and inflammatory response parameters.

    Science.gov (United States)

    Driessen, J J; Dhaese, H; Fransen, G; Verrelst, P; Rondelez, L; Gevaert, L; van Becelaere, M; Schelstraete, E

    1995-01-01

    The present study investigated the influence of pulsatile or nonpulsatile flow delivery with a centrifugal pump for cardiopulmonary bypass (CPB) during coronary artery bypass grafting (CABG) in two randomized groups of 19 patients each. All patients received a standard anaesthetic and surgical protocol. Pulsatile perfusion during CPB was created by accelerating the baseline pump speed of the Sarns centrifugal pump at a rate of 50 cycles per minute. Measurements included perioperative systemic haemodynamics and oxygen exchange, total haemolytic complement (CH50), polymorphonuclear (neutrophil) granulocyte (PMN) count and plasma granulocyte elastase bound to alpha 1-proteinase inhibitor (E-alpha 1-PI). Laboratory measurements were corrected for haemodilution. During and after CPB there were only a few significant differences between the groups in systemic haemodynamics and oxygenation, i.e. a lower mean arterial blood pressure after the end of CPB in the nonpulsatile group (65 mmHg, SD = 11 vs 76 mmHg, SD = 11) and a lower SvO2 during rewarming on CPB in the nonpulsatile group (62%, SD = 8 vs 67%, SD = 8). The decrease in percentage of PMNs in the total white blood cell count during CPB was greater in the nonpulsatile group than in the pulsatile group (from 61 to 46% vs 63 to 53% of prebypass value). The steep increase of PMN count at the end of CPB and postoperatively was comparable in both groups. The maximal decrease of CH50 levels, occurring after surgery, was significantly higher in the nonpulsatile group (70% SD = 15 vs 79%, SD = 16, of baseline value), suggesting a greater complement activation. E-alpha 1-PI levels increased significantly in both groups during and after CPB with higher peak levels, obtained at one hour after admission to an intensive care unit, in the nonpulsatile group (316 micrograms/l, SD = 102) than in the pulsatile group (247 micrograms/l, SD = 106). There was a partly inverse correlation between the peak postoperative elastase levels and

  4. Comparative study of effects of bone marrow cell vs. Ad5-HGF administration via non infarct-related artery injection in myocardial infarction in swine

    Institute of Scientific and Technical Information of China (English)

    Liansheng Wang; Jun Huang; Zhijian Yang; Wei Wang; Dongchao Ma; Shunlin Xu; Yuqing Zhang; Fang Zhou; Bo Chen; Kejiang Cao

    2007-01-01

    Objective: To evaluate the effect of transplanting bone marrow-derived mesenchymal stem cells (BM-MSCs) or adenovirus5-hepatocyte growth factor(Ad5-HGF) via non-infarct-related artery injection in swine myocardial infarction models. Methods :BMMSCs were obtained from swine bone marrow and expanded in vitro to a purity of >50%. A myocardial infarction(MI) was created by ligating the distal left anterior descending artery in swine. Either BM-MSCs (5 × 106/ml) or Ad5-HGF (4 × 109 pfu) were transfused via the right coronary artery (non-infarcted artery) four weeks after MI. Gate-controled cardiac perfusion imaging was performed at the end of four and seven weeks after LAD ligation, to evaluate heart function and cardiac perfusion. Morphologic and histologic characteristics of the hearts were also studied. Results: (1)The gate-controlled cardiac perfusion imaging showed that the improvement in LVEF was greater in both treatment groups than in control group at the 4th weeks. (2)In both treatment groups, capillary density was significantly higher than that of control group (P < 0.05). Conclusion:BM-MSCs or Ad5-HGF transplantation via non-infarcted artery administration can stimulate angiogenesis and improve heart function, but there was no difference in therapeutic efficacy between BM-MSCs and Ad5-HGF.

  5. Short term non-invasive ventilation post-surgery improves arterial blood-gases in obese subjects compared to supplemental oxygen delivery - a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Zoremba Norbert

    2011-05-01

    Full Text Available Abstract Background In the immediate postoperative period, obese patients are more likely to exhibit hypoxaemia due to atelectasis and impaired respiratory mechanics, changes which can be attenuated by non-invasive ventilation (NIV. The aim of the study was to evaluate the duration of any effects of early initiation of short term pressure support NIV vs. traditional oxygen delivery via venturi mask in obese patients during their stay in the PACU. Methods After ethics committee approval and informed consent, we prospectively studied 60 obese patients (BMI 30-45 undergoing minor peripheral surgery. Half were randomly assigned to receive short term NIV during their PACU stay, while the others received routine treatment (supplemental oxygen via venturi mask. Premedication, general anaesthesia and respiratory settings were standardized. We measured arterial oxygen saturation by pulse oximetry and blood gas analysis on air breathing. Inspiratory and expiratory lung function was measured preoperatively (baseline and at 10 min, 1 h, 2 h, 6 h and 24 h after extubation, with the patient supine, in a 30 degrees head-up position. The two groups were compared using repeated-measure analysis of variance (ANOVA and t-test analysis. Statistical significance was considered to be P Results There were no differences at the first assessment. During the PACU stay, pulmonary function in the NIV group was significantly better than in the controls (p Conclusion Early initiation of short term NIV during in the PACU promotes more rapid recovery of postoperative lung function and oxygenation in the obese. The effect lasted 24 hours after discontinuation of NIV. Patient selection is necessary in order to establish clinically relevant improvements. Trial Registration# DRKS00000751; http://www.germanctr.de

  6. Numerical Simulation of Coronary Artery Bypass Graft with an Assistant Graft

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; WANG Feng

    2014-01-01

    The conventional bypass design is to implant a graft on the stenosed host artery allowing blood to flow bypass the stenotic artery. However, restenosis is a challenging problem which finally results in reoperation. The purpose of this paper is to propose a new bypass graft design of coronary artery with an assistant graft for the treatment of coronary artery stenosis. An additional assistant graft was employed in the new design compared with the conventional ETS anastomosis. Numerical simulations were performed by means of finite volume method using computational fluid dynamics (CFD) solver. Results demonstrated that the new anastomoses model provided a more smooth flow at the distal ETS anastomosis without any stagnation point on anastomotic bed and vortex formation in the heel region. Oscillatory shear index (OSI) and time-averaged wall shear stress gradient (TAWSSG) at the artery bed of the distal ETS anastomosis were reduced. The coronary artery bypass graft with an assistant graft is feasible to improve the local hemodynamics and diminish the probability of restenosis in the treatment of coronary artery stenosis.

  7. Prospective Evaluation of Transcatheter Arterial Chemoembolization (TACE) with Multiple Anti-Cancer Drugs (Epirubicin, Cisplatin, Mitomycin C, 5-Fluorouracil) Compared with TACE with Epirubicin for Treatment of Hepatocellular Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Sahara, Shinya; Kawai, Nobuyuki; Sato, Morio, E-mail: morisato@mail.wakayama-med.ac.jp; Tanaka, Takami; Ikoma, Akira; Nakata, Kouhei; Sanda, Hiroki; Minamiguchi, Hiroki; Nakai, Motoki; Shirai, Shintaro; Sonomura, Tetsuo [Wakayama Medical University, Department of Radiology (Japan)

    2012-12-15

    Purpose: To compare the efficacy of transcatheter arterial chemoembolization (TACE) using multiple anticancer drugs (epirubicin, cisplatin, mitomycin C, and 5-furuorouracil: Multi group) with TACE using epirubicin (EP group) for hepatocellular carcinoma (HCC). Materials and Methods: The study design was a single-center, prospective, randomized controlled trial. Patients with unrespectable HCC confined to the liver, unsuitable for radiofrequency ablation, were assigned to the Multi group or the EP group. We assessed radiographic response as the primary endpoint; secondary endpoints were progression-free survival (PFS), safety, and hepatic branch artery abnormality (Grade I, no damage or mild vessel wall irregularity; Grade II, overt stenosis; Grade III, occlusion; Grades II and III indicated significant hepatic artery damage). A total of 51 patients were enrolled: 24 in the Multi group vs. 27 in the EP group. Results: No significant difference in HCC patient background was found between the groups. Radiographic response, PFS, and 1- and 2-year overall survival of the Multi vs. EP group were 54% vs. 48%, 6.1 months vs. 8.7 months, and 95% and 65% vs. 85% and 76%, respectively, with no significant difference. Significantly greater Grade 3 transaminase elevation was found in the Multi group (p = 0.023). Hepatic artery abnormality was observed in 34% of the Multi group and in 17.1% of the EP group (p = 0.019). Conclusion: TACE with multiple anti-cancer drugs was tolerable but appeared not to contribute to an increase in radiographic response or PFS, and caused significantly more hepatic arterial abnormalities compared with TACE with epirubicin alone.

  8. Ex Vivo and in Silico Study of Human Common Carotid Arteries Pressure Response in Physiological and Inverted State

    Science.gov (United States)

    Piechna, A.; Cieślicki, K.; Lombarski, L.; Ciszek, B.

    2015-02-01

    Arterial walls are a multilayer structures with nonlinear material characteristics. Furthermore, residual stresses exist in unloaded state (zero-pressure condition) and they affect arterial behavior. To investigate these phenomena a number of theoretical and numerical studies were performed, however no experimental validation was proposed and realized yet. We cannot get rid of residual stresses without damaging the arterial segment. In this paper we propose a novel experiment to validate a numerical model of artery with residual stresses. The inspiration for our study originates from experiments made by Dobrin on dogs' arteries (1999). We applied the idea of turning the artery inside out. After such an operation the sequence of layer is reversed and the residual stresses are re-ordered. We performed several pressure-inflation tests on human Common Carotid Arteries (CCA) in normal and inverted configurations. The nonlinear responses of arterial behavior were obtained and compared to the numerical model. Computer simulations were carried out using the commercial software which applied the finite element method (FEM). Then, these results were discussed.

  9. Reference values for local arterial stiffness. Part B : femoral artery

    NARCIS (Netherlands)

    Bossuyt, Jelle; Engelen, Lian; Ferreira, Isabel; Stehouwer, Coen D; Boutouyrie, Pierre; Laurent, Stéphane; Segers, Patrick; Reesink, Koen; Van Bortel, Luc M

    2015-01-01

    OBJECTIVE: Carotid-femoral pulse wave velocity (PWV) is considered the gold standard measure of arterial stiffness, representing mainly aortic stiffness. As compared with the elastic carotid and aorta, the more muscular femoral artery may be differently associated with cardiovascular risk factors (C

  10. COMPARATIVE STUDY OF COMBINED DRUGS OF ENALAPRIL MALEATE AND HYDROCHLOROTHIAZIDE: «RENIPRIL HT» AND «CO-RENITEC» IN PATIENTS WITH MILD TO MODERATE ARTERIAL HYPERTENSION

    Directory of Open Access Journals (Sweden)

    S. Y. Martsevich

    2015-12-01

    Full Text Available Aim. Tto study efficiency and safety of new combined drug of enalapril maleate and hydrochlorothiazide “Renipril HT: in patients with mild to moderate arterial hypertension (AH in comparison with the original combined drug with the same substances – “Co-renitec”, possibility of reaching target blood pressure (BP level with separate treatment with each drug, and in combination with atenolol if necessary.Material and methods. 30 patients (11 men and 19 women with mild to moderate AH took part in randomized, open, cross over study. 10-14 days before the study started, previous antihypertensive treatment had been canceled for all the patients. Each patient by turns was treated during 6 weeks with Renipril HT (RH and Co-renitec (CR. Efficiency of antihypertensive therapy was assessed at visits to physician every 2 weeks within the whole period of study. Within first 2 weeks patients were treated with RH 10/12,5 mg daily or CR 10/6,25 mg daily. Within next 2 weeks doses of drugs were doubled if target BP level (<140/90 mmHg was not reached. If therapy with doubled doses of combined drugs was inefficient, atenolol 25 mg daily was added for the last 2 weeks of treatment with each drug. After 6-week treatment with the first randomized drug, antihypertensive therapy was canceled for 7-14 days depending on addition of atenolol to the therapy.Results. After 6-week treatment with RH average level of systolic BP reduced by 21,8 mmHg compared to the initial level, after 6-week treatment with CR – by 23,8 mmHg. Average level of diastolic BP reduced by 10,8 and 13,5 mmHg respectively (differences between drugs in BP decrease are not significant. By the end of 6-week treatment with RH target BP level was reached in 74% of patients, with CR - in 64% of patients. Bigger number of side-effects was registered in treatment with RH (p=0,03, but most part of them were not severe and didn’t demand therapy correction.Conclusion. New combined drug of enalapril

  11. COMPARATIVE STUDY OF COMBINED DRUGS OF ENALAPRIL MALEATE AND HYDROCHLOROTHIAZIDE: «RENIPRIL HT» AND «CO-RENITEC» IN PATIENTS WITH MILD TO MODERATE ARTERIAL HYPERTENSION

    Directory of Open Access Journals (Sweden)

    S. Y. Martsevich

    2005-01-01

    Full Text Available Aim. Tto study efficiency and safety of new combined drug of enalapril maleate and hydrochlorothiazide “Renipril HT: in patients with mild to moderate arterial hypertension (AH in comparison with the original combined drug with the same substances – “Co-renitec”, possibility of reaching target blood pressure (BP level with separate treatment with each drug, and in combination with atenolol if necessary.Material and methods. 30 patients (11 men and 19 women with mild to moderate AH took part in randomized, open, cross over study. 10-14 days before the study started, previous antihypertensive treatment had been canceled for all the patients. Each patient by turns was treated during 6 weeks with Renipril HT (RH and Co-renitec (CR. Efficiency of antihypertensive therapy was assessed at visits to physician every 2 weeks within the whole period of study. Within first 2 weeks patients were treated with RH 10/12,5 mg daily or CR 10/6,25 mg daily. Within next 2 weeks doses of drugs were doubled if target BP level (<140/90 mmHg was not reached. If therapy with doubled doses of combined drugs was inefficient, atenolol 25 mg daily was added for the last 2 weeks of treatment with each drug. After 6-week treatment with the first randomized drug, antihypertensive therapy was canceled for 7-14 days depending on addition of atenolol to the therapy.Results. After 6-week treatment with RH average level of systolic BP reduced by 21,8 mmHg compared to the initial level, after 6-week treatment with CR – by 23,8 mmHg. Average level of diastolic BP reduced by 10,8 and 13,5 mmHg respectively (differences between drugs in BP decrease are not significant. By the end of 6-week treatment with RH target BP level was reached in 74% of patients, with CR - in 64% of patients. Bigger number of side-effects was registered in treatment with RH (p=0,03, but most part of them were not severe and didn’t demand therapy correction.Conclusion. New combined drug of enalapril

  12. Patient Satisfaction After Femoral Arterial Access Site Closure Using the ExoSeal{sup ®} Vascular Closure Device Compared to Manual Compression: A Prospective Intra-individual Comparative Study

    Energy Technology Data Exchange (ETDEWEB)

    Pieper, Claus Christian, E-mail: claus.christian.pieper@ukb.uni-bonn.de; Thomas, Daniel, E-mail: daniel.thomas@ukb.uni-bonn.de [University of Bonn, Department of Radiology (Germany); Nadal, Jennifer, E-mail: jennifer.nadal@ukb.uni-bonn.de [University of Bonn, Institute for Medical Biometry, Informatics and Epidemiology (Germany); Willinek, Winfried A., E-mail: w.willinek@bk-trier.de; Schild, Hans Heinz, E-mail: hans.schild@ukb.uni-bonn.de; Meyer, Carsten, E-mail: carsten.meyer@ukb.uni-bonn.de [University of Bonn, Department of Radiology (Germany)

    2016-01-15

    PurposeTo intra-individually compare discomfort levels and patient satisfaction after arterial access closure using the ExoSeal{sup ®} vascular closure device (VCD) and manual compression (MC) in a prospective study design.MethodsPatients undergoing two planned interventions from 07/2013 to 09/2014 could participate in the study. Access closure was performed with an ExoSeal{sup ®}-VCD in one and MC in the other intervention. Patients were clinically and sonographically examined and were given questionnaires 1 day after intervention [groin- and back-pain during bedrest (100-point visual analog scale; 0: no pain); comfortability of bedrest (10-point Likert scale, 1: comfortable), satisfaction with closure (10-point Likert scale, 1: very satisfied)]. Results were analyzed in a cross-over design.Results48 patients (29 male, median age 62.5 (32–88) years) were included. An ExoSeal{sup ®}-VCD was used first in 25 cases. As four of these subsequently refused MC as second intervention, data from 44 patients could be analyzed. All closures were technically successful (successful device deployment) without major complications. Groin- and back-pain after VCD-use/MC was 0 (0–15) vs. 10 (0–80) and 0 (0–75) vs. 25 (0–90), respectively (p < 0.0001). Bedrest after VCD-use was more comfortable than after MC [1 (range 1–7) vs. 6 (2–10); p < 0.0001]. Satisfaction with the closure procedure and with the intervention in general was higher after VCD-use compared to MC [1 (1–3) vs. 5 (2–10) and 1 (1–2) vs. 2 (1–4), respectively; p < 0.0001].ConclusionIntra-individual comparison showed pain levels and discomfort to be significantly lower after ExoSeal{sup ®} use compared to MC. VCD closure was associated with higher satisfaction both with the closure itself and with the intervention in general.

  13. Nitinol Stent Fatigue in a Peripheral Human Artery Subjected to Pulsatile and Articulation Loading

    Science.gov (United States)

    Harvey, Sean Michael

    2011-07-01

    Nitinol self-expanding stents are used to treat peripheral occluded vessels such as the superficial femoral artery or the carotid. The complex vessel articulation requires a stent device that is flexible and kink resistant yet durable. The present study shows how the latest advances in commercially available engineering software tools permit engineering simulations of the many aspects of the Nitinol stent design and analysis. Two stent geometries are evaluated: a helical type stent design, and a more traditional straight strut, with multiple crowns design. The fatigue performance of the two stents is compared. The results show that advanced nonlinear finite element simulations and fatigue predictions of the Nitinol stent are possible today inside realistic simulated human arteries. The finite element analysis software used in this study is SimXpert, Marc, and Mentat (MSC Software, Santa Ana, CA).

  14. RADAR – A randomised, multi-centre, prospective study comparing best medical treatment versus best medical treatment plus renal artery stenting in patients with haemodynamically relevant atherosclerotic renal artery stenosis

    Directory of Open Access Journals (Sweden)

    Hauk Michael

    2009-07-01

    Full Text Available Abstract Background Prospective, international, multi-centre, randomised (1:1 trial to evaluate the clinical impact of percutaneous transluminal renal artery stenting (PTRAS on the impaired renal function measured by the estimated glomerular filtration rate (eGFR in patients with haemodynamically significant atherosclerotic renal artery stenosis. Methods Patients will be randomised to receive either PTRAS using the Dynamic Renal Stent system plus best medical treatment or best medical treatment. Renal stenting will be performed under angiographic imaging. For patients randomised to best medical treatment the degree of stenosis measured by renal duplex sonography (RDS will be confirmed by MR angio or multi-slice CT where possible. Best medical treatment will be initiated at randomisation or post procedure (for PTRAS arm only, and adjusted as needed at all visits. Best medical treatment is defined as optimal drug therapy for control of the major risk factors (blood pressure ≤ 125/80 mmHg, LDL cholesterol ≤ 100 mg/dL, HbA1c ≤ 6.5%. Data recordings include serum creatinine values, eGFR, brain natriuretic peptide, patients' medical history and concomitant medication, clinical events, quality of life questionnaire (SF-12v2™, 24 hour ambulatory blood pressure measurement, renal artery duplex ultrasound and echocardiography. Follow-up intervals are at 2, 6, 12 and 36 months following randomisation. The primary endpoint is the difference between treatments in change of eGFR over 12 months. Major secondary endpoints are technical success, change of renal function based on the eGFR slope change between pre-treatment and post-treatment (i.e. improvement, stabilisation, failure, clinical events overall such as renal or cardiac death, stroke, myocardial infarction, hospitalisation for congestive heart failure, progressive renal insufficiency (i.e. need for dialysis, need of target vessel revascularisation or target lesion revascularisation, change in

  15. Carotid artery surgery

    Science.gov (United States)

    Carotid endarterectomy; CAS surgery; Carotid artery stenosis - surgery; Endarterectomy - carotid artery ... through the catheter around the blocked area during surgery. Your carotid artery is opened. The surgeon removes ...

  16. Age, hypertension and arterial function.

    Science.gov (United States)

    McEniery, Carmel M; Wilkinson, Ian B; Avolio, Albert P

    2007-07-01

    1. Ageing exerts a marked effect on the cardiovascular system and, in particular, the large arteries. Using a variety of techniques to assess arterial stiffness, many cross-sectional studies have demonstrated a significant relationship between age and aortic stiffness, although the age-related changes observed in peripheral arteries appear to be less marked. 2. The relationship between arterial stiffness and hypertension is more complex. The distending, or mean arterial, pressure is an important confounder of measurements of arterial stiffness and, therefore, must be taken into consideration when assessing arterial stiffness in hypertensive subjects or investigating the effect of antihypertensive agents. Current methods for correcting for differences in distending pressure involve pharmacological manipulation, statistical correction or mathematical manipulation of stiffness indices. 3. Many studies have provided evidence that both peripheral (muscular) and central (elastic) arteries are stiffer in subjects with mixed (systolic/diastolic) hypertension compared with normotensive subjects. However, it is unclear to what extent differences in mean arterial pressure explain the observed differences in hypertensive subjects. In contrast, isolated systolic hypertension is associated with increased aortic, but not peripheral artery, stiffness, although the underlying mechanisms are somewhat unclear. 4. Traditional antihypertensive agents appear to reduce arterial stiffness, but mostly via an indirect effect of lowering mean pressure. Therefore, therapies that target the large arteries to reduce stiffness directly are urgently required. Agents such as nitric oxide donors and phosphodiesterase inhibitors may be useful in reducing stiffness via functional mechanisms. In addition, inhibitors or breakers of advanced glycation end-product cross-links between proteins, such as collagen and elastin, hold substantial promise.

  17. Poisson׳s ratio of arterial wall - Inconsistency of constitutive models with experimental data.

    Science.gov (United States)

    Skacel, Pavel; Bursa, Jiri

    2016-02-01

    Poisson׳s ratio of fibrous soft tissues is analyzed in this paper on the basis of constitutive models and experimental data. Three different up-to-date constitutive models accounting for the dispersion of fibre orientations are analyzed. Their predictions of the anisotropic Poisson׳s ratios are investigated under finite strain conditions together with the effects of specific orientation distribution functions and of other parameters. The applied constitutive models predict the tendency to lower (or even negative) out-of-plane Poisson׳s ratio. New experimental data of porcine arterial layer under uniaxial tension in orthogonal directions are also presented and compared with the theoretical predictions and other literature data. The results point out the typical features of recent constitutive models with fibres concentrated in circumferential-axial plane of arterial layers and their potential inconsistence with some experimental data. The volumetric (in)compressibility of arterial tissues is also discussed as an eventual and significant factor influencing this inconsistency.

  18. Diagnóstico clínico diferencial entre oclusão da artéria carótida interna e da artéria cerebral média A comparative symptomatological study of internal carotid artery occlusion and middle cerebral artery occlusion

    Directory of Open Access Journals (Sweden)

    Roberto Melaragno

    1971-03-01

    Full Text Available Foi feito um estudo comparativo entre o quadro clínico inicial de 61 casos de oclusão da artéria carótida interna e o de 23 casos de oclusão da artéria cerebral média, diagnosticados pela angiografia cerebral e/ou pela necropsia em pacientes submetidos ou não à cirurgia vascular. Os autores comparam a idade dos pacientes, o sexo, o modo de início da afecção, a existência ou não de convulsões e/ou cefaléias, a ocorrência do acidente cerebral durante o sono ou em vigília, a existência de ictos prévios, os níveis de pressão arterial, o grau de consciência, a força muscular, os achados eletrencefalográficos, a palpação e ausculta das carótidas em nível cervical. Os resultados são demonstrados em índices percentuais, pelos quais os autores inferem que não há significância estatística nesses elementos com três exceções: a maior ocorrência de convulsões nas oclusões da artéria cerebral média em relação às da carótida, a oftalmodinamometria e a sintomatologia carotídea cervical. A oftalmodinamometria revela valores significantemente menores nas pressões da artéria central da retina, no mesmo lado da trombose da carótida em 70,0% dos casos, enquanto que medidas normais e simétricas verificaram-se em todos os casos de oclusão da artéria cerebral média em que o exame foi realizado. No que concerne a sinais arteriais no pescoço, havia anormalidades palpatórias e auscultatórias em 52,4% dos pacientes com trombose da carótida e em 8,6% dos casos com oclusão da cerebral média. Concluem os autores, portanto, que apenas a angiografia cerebral permite um diagnóstico seguro entre ambas as sedes da oclusão.A comparative study of the early clinical picture in 61 cases of internal carotid artery occlusion and 23 cases of middle cerebral artery occlusion, diagnosed by cerebral angiography and/or necropsy in patients who were either submitted to surgery or not operated upon is reported. The authors had

  19. Coronary artery fistula

    Science.gov (United States)

    Congenital heart defect - coronary artery fistula; Birth defect heart - coronary artery fistula ... A coronary artery fistula is often congenital, meaning that it is present at birth. It generally occurs when one of the coronary arteries ...

  20. Comparing iterative solvers for linear systems associated with the finite difference discretisation of the forward problem in electro-encephalographic source analysis.

    Science.gov (United States)

    Mohr, M; Vanrumste, B

    2003-01-01

    Model-based reconstruction of electrical brain activity from electro-encephalographic measurements is of growing importance in neurology and neurosurgery. Algorithms for this task involve the solution of a 3D Poisson problem on a realistic head geometry obtained from medical imaging. In the model, several compartments with different conductivities have to be distinguished, leading to a problem with jumping coefficients. Furthermore, the Poisson problem needs to be solved repeatedly for different source contributions. Thus efficient solvers for this subtask are required. Experience with different iterative solvers is reported, i.e. successive over-relaxation, (preconditioned) conjugate gradients and algebraic multigrid, for a discretisation based on cell-centred finite differences. It was found that: first, the multigrid-based solver performed the task 1.8-3.5 times faster, depending on the platform, than the second-best contender; secondly, there was no need to introduce a reference potential that forced a unique solution; and, thirdly, neither the grid- nor matrix-based implementation of the solvers consistently gave a smaller run time.

  1. NONLINEAR ELASTICITY OF BLOOD ARTERIAL DUCT

    Institute of Scientific and Technical Information of China (English)

    黄孟才; 顾忠; 沈俊; 唐复勇

    1991-01-01

    The paper deals with nonlinear elasticity of blood arterial duct, in which the artery is modeled to bea locally triclinic, transverse isotropic, incorapressible, axisymmetric and thickwalled tube with large deformations, The nonlinear coustitutive relationship of arterial tissues is based on the theorv of Green and Adkins. A nonlinear strain energy density function is introduced for nonlinear stress-strain relationship of second order, in which the coefficient of each term is expressed by means of a Lame’s constant, The elasticity constants are nqcessary to describe such a uonlinear finite strain etastieity of the second order, These constants are determined by means of the stress-strain increment theory.

  2. A comparative study on the uniaxial mechanical properties of the umbilical vein and umbilical artery using different stress-strain definitions.

    Science.gov (United States)

    Karimi, Alireza; Navidbakhsh, Mahdi

    2014-12-01

    The umbilical cord is part of the fetus and generally includes one umbilical vein (UV) and two umbilical arteries (UAs). As the saphenous vein and UV are the most commonly used veins for the coronary artery disease treatment as a coronary artery bypass graft (CABG), understating the mechanical properties of UV has a key asset in its performance for CABG. However, there is not only a lack of knowledge on the mechanical properties of UV and UA but there is no agreement as to which stress-strain definition should be implemented to measure their mechanical properties. In this study, the UV and UA samples were removed after caesarean from eight individuals and subjected to a series of tensile testing. Three stress definitions (second Piola-Kichhoff stress, engineering stress, and true stress) and four strain definitions (Almansi-Hamel strain, Green-St. Venant strain, engineering strain, and true strain) were employed to determine the linear mechanical properties of UVs and UAs. The nonlinear mechanical behavior of UV/UA was computationally investigated using hyperelastic material models, such as Ogden and Mooney-Rivlin. The results showed that the effect of varying the stress definition on the maximum stress measurements of the UV/UA is significant but not when calculating the elastic modulus. In the true stress-strain diagram, the maximum strain of UV was 92 % higher, while the elastic modulus and maximum stress were 162 and 42 % lower than that of UA. The Mooney-Rivlin material model was designated to represent the nonlinear mechanical behavior of the UV and UA under uniaxial loading.

  3. Brachial artery vasomotion and transducer pressure effect on measurements by active contour segmentation on ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Cary, Theodore W.; Sultan, Laith R.; Sehgal, Chandra M., E-mail: sehgalc@uphs.upenn.edu [Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Reamer, Courtney B.; Mohler, Emile R. [Department of Medicine, Division of Cardiovascular Medicine, Section of Vascular Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2014-02-15

    Purpose: To use feed-forward active contours (snakes) to track and measure brachial artery vasomotion on ultrasound images recorded in both transverse and longitudinal views; and to compare the algorithm's performance in each view. Methods: Longitudinal and transverse view ultrasound image sequences of 45 brachial arteries were segmented by feed-forward active contour (FFAC). The segmented regions were used to measure vasomotion artery diameter, cross-sectional area, and distention both as peak-to-peak diameter and as area. ECG waveforms were also simultaneously extracted frame-by-frame by thresholding a running finite-difference image between consecutive images. The arterial and ECG waveforms were compared as they traced each phase of the cardiac cycle. Results: FFAC successfully segmented arteries in longitudinal and transverse views in all 45 cases. The automated analysis took significantly less time than manual tracing, but produced superior, well-behaved arterial waveforms. Automated arterial measurements also had lower interobserver variability as measured by correlation, difference in mean values, and coefficient of variation. Although FFAC successfully segmented both the longitudinal and transverse images, transverse measurements were less variable. The cross-sectional area computed from the longitudinal images was 27% lower than the area measured from transverse images, possibly due to the compression of the artery along the image depth by transducer pressure. Conclusions: FFAC is a robust and sensitive vasomotion segmentation algorithm in both transverse and longitudinal views. Transverse imaging may offer advantages over longitudinal imaging: transverse measurements are more consistent, possibly because the method is less sensitive to variations in transducer pressure during imaging.

  4. Myocardial scintigraphy with iodine-123 phenylpentadecanoic acid and thallium-201 in patients with coronary artery disease: A comparative dual-isotope study

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, R.; Rauch, B.; Kapp, M.; Neumann, F.J.; Seitz, F.; Kuebler, W. (Heidelberg Univ. (Germany). Dept. of Cardiology); Bubeck, B. (Heidelberg Univ. (Germany). Dept. of Nuclear Medicine); Mall, G. (Heidelberg Univ. (Germany). Dept. of Pathology); Tillmanns, H. (Giessen Univ. (Germany). Dept. of Cardiology); Stokstad, P.

    1992-11-01

    To characterise the clinical usefulness of serial myocardial scintigraphy with iodine-123 phenylpentadecanoic acid (IPPA) in comparison with thallium-201, dual-isotope investigations were performed in 41 patients with angiographically documented coronary artery disease. Both tracers were adminstered simultaneously during symptom-limited ergometry. Planar scintigrams were acquired immediately after stress, and delayed imaging was performed after 1 h for IPPA and 4 h for {sup 201}Tl. Scintigrams were evaluated both qualitatively and quantitatively using a newly developed algorithm for automated image superposition. Initial myocardial uptake of both tracers was closely correlated (r=0.75, p<0.001). Both tracers also revealed a similar sensitivity for the identification of individual coronary artery stenoses {>=}75% (IPPA: 70%, {sup 201}Tl: 66.3%, P=NS) with identical specificity (69.8%). The number of persistent defects, however, was significantly higher with IPPA (P=0.021), suggesting that visual analysis of serial IPPA scintigrams may overestimate the presence of myocardial scar tissue. On the other hand, previous Q wave myocardial infarction was associated with a decreased regional IPPA clearance (29%{+-}11% vs 44%{+-}11% in normal myocardium, P<0.05). The data indicate that serial myocardial scintigraphy with IPPA is essentially as sensitive as scintigraphy with {sup 201}Tl for the detection of stress-induced perfusion abnormalities. Quantitative analysis of myocardial IPPA kinetics, however, is required for the evaluation of tissue viability. (orig.).

  5. Waist circumference compared with other obesity parameters as determinants of coronary artery disease in essential hypertension: a 6-year follow-up study.

    Science.gov (United States)

    Dimitriadis, Kyriakos; Tsioufis, Costas; Mazaraki, Anastasia; Liatakis, Ioannis; Koutra, Evaggelia; Kordalis, Athanasios; Kasiakogias, Alexandros; Flessas, Dimitrios; Tentolouris, Nicholas; Tousoulis, Dimitris

    2016-06-01

    This study aimed to assess the predictive role of body mass index (BMI), waist circumference (WC) and the waist-to-hip ratio (WHR) for the incidence of coronary artery disease (CAD) in a cohort of essential hypertensive patients. We followed up 2266 essential hypertensive individuals (mean age, 57.8 years; males, 1083; office blood pressure (BP), 143/89 mm Hg) who were free of cardiovascular disease for a mean period of 6 years. All subjects had at least one annual visit and, at baseline, underwent blood sampling and a complete echocardiographic study to determine the left ventricular (LV) mass index. CAD was defined as a history of myocardial infarction or significant coronary artery stenosis that was revealed by angiography or a coronary revascularization procedure. The incidence of CAD throughout the follow-up period was 2.33%. Hypertensive individuals who developed CAD (n=53) had a greater baseline WC (101.1±11.7 vs. 96.4±12 cm, P=0.005), WHR (0.94±0.07 vs. 0.89±0.08 cm, Pobesity.

  6. Association between internal carotid artery dissection and arterial tortuosity

    Energy Technology Data Exchange (ETDEWEB)

    Saba, Luca; Piga, Mario [Azienda Ospedaliero Universitaria (A.O.U.), Department of Radiology, Monserrato, Cagliari (Italy); Argiolas, Giovanni Maria; Siotto, Paolo [Azienda Ospedaliero Brotzu (A.O.B.), Department of Radiology, di Cagliari (Italy); Sumer, Suna; Wintermark, Max [Neuroradiology Division, Neuroradiology, UVA Department of Radiology, Charlottesville, VA (United States); Raz, Eytan [New York University School of Medicine, Department of Radiology, New York, NY (United States); Sapienza University of Rome, Department of Neurology and Psychiatry, Rome (Italy); Sanfilippo, Roberto; Montisci, Roberto [Azienda Ospedaliero Universitaria (A.O.U.), Department of Vascular Surgery, di Cagliari (Italy)

    2014-10-18

    Carotid artery dissection is an important cause of ischemic stroke in all age groups, particularly in young patients. The purpose of this work was to assess whether there is an association between the presence of an internal carotid artery dissection (ICAD) and the arterial tortuosity. This study considered 124 patients (72 males and 52 females; median age 57 years) with CT/MR diagnosis of ICAD of the internal carotid artery were considered in this multi-centric retrospective study. The arterial tortuosity was evaluated and, when present, was categorized as elongation, kinking, or coiling. For each patient, both the right and left sides were considered for a total number of 248 arteries in order to have the same number of cases and controls. Fisher's exact test was applied to test the association between elongation, kinking, coiling, dissection, and the side affected by CAD. Fisher's exact test showed a statistically significant association between the ICAD and kinking (p = 0.0089) and coiling (p = 0.0251) whereas no statistically significant difference was found with arterial vessel elongation (p = 0.444). ICAD was more often seen on the left side compared to the right (p = 0.0001). These results were confirmed using both carotid arteries of the same patient as dependent parameter with p = 0.0012, 0.0129, and 0.3323 for kinking, coiling, and elongation, respectively. The presence of kinking and coiling is associated with ICAD. (orig.)

  7. Obesity and arterial compliance alterations.

    Science.gov (United States)

    Seifalian, Alexander M; Filippatos, Theodosios D; Joshi, Jatin; Mikhailidis, Dimitri P

    2010-03-01

    Obesity is associated with increased cardiovascular disease (CVD) risk, especially when excess body fat is distributed preferentially within the abdominal region. Obese subjects usually have increased arterial stiffness compared with non-obese subjects of similar age. The factors associated with increased arterial stiffness in obesity include endothelial dysfunction (decreased nitric oxide bioavailability), impaired smooth muscle cell function, insulin resistance, as well as elevated cholesterol and C-peptide levels. Furthermore, visceral fat, the adipose tissue-related renin-angiotensin-aldosterone system and hyperleptinaemia contribute to the obesity-associated impaired arterial compliance. Weight loss improves CVD risk factors and arterial compliance. Because increased arterial stiffness is a marker of CVD risk these findings support the concept that the presence of obesity has vascular implications.

  8. The contrast-enhanced Doppler ultrasound with perfluorocarbon exposed sonicated albumin does not improve the diagnosis of renal artery stenosis compared with angiography

    Directory of Open Access Journals (Sweden)

    Bortolotto Luiz A

    2004-09-01

    Full Text Available Abstract There are no studies investigating the effect of the contrast infusion on the sensitivity and specificity of the main Doppler criteria of renal artery stenosis (RAS. Our aim was to evaluate the accuracy of these Doppler criteria prior to and following the intravenous administration of perfluorocarbon exposed sonicated albumin (PESDA in patients suspected of having RAS. Thirty consecutive hypertensive patients (13 males, mean age of 57 ± 10 years suspected of having RAS by clinical clues, were submitted to ultrasonography (US of renal arteries before and after enhancement using continuous infusion of PESDA. All patients underwent angiography, and haemodynamically significant RAS was considered when ≥50%. At angiography, it was detected RAS ≥50% in 18 patients, 5 with bilateral stenosis. After contrast, the examination time was slightly reduced by approximately 20%. In non-enhanced US the sensitivity was better when based on resistance index (82.9% while the specificity was better when based on renal aortic ratio (89.2%. The predictive positive value was stable for all indexes (74.0%–88.0% while negative predictive value was low (44%–51%. The specificity and positive predictive value based on renal aortic ratio increased after PESDA injection respectively, from 89 to 97.3% and from 88 to 95%. In hypertensives suspected to have RAS the sensitivity and specificity of Duplex US is dependent of the criterion evaluated. Enhancement with continuous infusion of PESDA improves only the specificity based on renal aortic ratio but do not modify the sensitivity of any index.

  9. Evaluation of renal artery stenosis using color Doppler sonography in young patients with multiple renal arteries

    Institute of Scientific and Technical Information of China (English)

    QIN Wei; ZHANG Xin; YANG Min; ZHONG Xu-hui; ZHAO Ming-hui

    2011-01-01

    Background Some individuals have multiple renal arteries. Severe stenosis in one of the arteries may cause refractory hypertension. The detection of stenosis within one of the multiple renal arteries usually required invasive procedures, such as computed tomographic angiography (CTA) and magnetic resonance angiography (MRA). This study reported the application of color Doppler sonography (CDS) in the detection of severe stenosis in one of the multiple arteries.Methods Patients with multiple renal arteries and one of the arteries with severe stenosis were retrospectively studied. Peak systolic velocities (PSV) of renal arteries and the intrarenal CDS patterns were collected and compared. The diagnosis was confirmed by digital subtraction angiography (DSA).Results Four children with multiple renal arteries and one of the arteries with stenosis were investigated. They were admitted due to refractory hypertension. CDS screening identified two renal arteries in one kidney of each patient with one of the two renal arteries having stenosis >70%. The PSV of the stenosed arteries were much higher, and the intrarenal CDS patterns supplied by the stenosed arteries changed into T-P patterns.Conclusion Non-invasive CDS technology may be a useful method to identify severe stenosis in one of multiple renal arteries in young patients.

  10. 冠状动脉螺旋CT成像与冠状动脉造影的对比性研究%A comparative study of coronary artery imaging with MSCT and coronary angiography

    Institute of Scientific and Technical Information of China (English)

    李忠银

    2008-01-01

    Objective To evaluate the value of multi-slice spiral CT (sixteen - detector row spiral CT) in diagnosing cor- onary artery disease. Methods One hundred and two patients of suspected coronary artery diseases have undergone sixteen slice spiral CT coronary angiography and conventional percutaneous coronary angiography. Then coronary artery stenosis were quantita- tively assessed in coronary artery segments. We considered the result of percutaneous coronary angiography as the gold standard and compared results of the two different diagnostic methods to determine the accuracy of 16 slice spiral CT. Results Compared with percutaneous coronary angiography, the sensitivity of sixteen slice spiral CT in diagnosing moderate and severe coronary ste- nosis was 92. 5% (210/227), and the specificness, positive predictive value, negative predictive value and degree of accuracy was 89.2% (544/610), 76.1% (210/276), 96.9% (544/561) and 90.0% (754/837) respectively. By including nonasses- sable arteries, the overall degree of accuracy decreased to 73.9% (754/1020). Conclusion Sixteen slice spiral CT coronary angiography has clinical value in diagnosing coronary artery disease, but its diagnostic accuracy is limited and it can' t replace the conventional percutaneous coronary angiography at present.%目的 探讨多层螺旋CT(16层螺旋CT)冠状动脉成像对冠心病的诊断价值.方法 对102例临床疑诊冠心病的患者行16层螺旋CT冠状动脉成像和经皮选择性冠状动脉造影术.对16层螺旋CT显示冠状动脉狭窄和经皮选择性冠状动脉造影显示冠状动脉狭窄进行定量评价.以经皮选择性冠状动脉造影结果作为诊断的金标准.依冠脉节段计算出16层螺旋CT冠状动脉成像对冠状动脉狭窄的诊断准确性指标.结果 16层螺旋CT冠状动脉成像对照经皮选择性冠状动脉造影对冠状动脉中、重度狭窄显示的对照结果:敏感性92.5%(210/227)、特异性89.2%(544/610)

  11. A comparative study of intra canal stress pattern in endodontically treated teeth with average sized canal diameter and reinforced wide canals with three different post systems using finite element analysis

    Directory of Open Access Journals (Sweden)

    Kaur Amandeep

    2010-01-01

    Full Text Available Study methodology: This is a comparative study of intra canal stress patterns in endodontically treated maxillary central incisor with: average sized canal diameter and wide canals reinforced with three different post systems - cast post and core, carbon fiber post, stainless steel post; restored with ceramic crown using finite element analysis (FEA. All the models were subjected to a force of 100N applied at 450 to the long axis of the tooth at the middle third of the palatal surface of the restored ceramic crown. Results: The FEA revealed that all the post systems showed maximum stress in the coronal and middle third of the root. Maximum stress was seen on the inner dentinal wall in case of stainless steel post followed by cast gold and carbon fiber post, both in the models without reinforcement as well as in the reinforced models.

  12. Comparative stress distribution of implant-retained mandibular ball-supported and bar-supported overlay dentures: a finite element analysis.

    Science.gov (United States)

    Vafaei, Fariborz; Khoshhal, Masoumeh; Bayat-Movahed, Saeed; Ahangary, Ahmad Hassan; Firooz, Farnaz; Izady, Alireza; Rakhshan, Vahid

    2011-08-01

    Implant-retained mandibular ball-supported and bar-supported overlay dentures are the two most common treatment options for the edentulous mandible. The superior option in terms of strain distribution should be determined. The three-dimensional model of mandible (based on computerized tomography scan) and its overlying implant-retained bar-supported and ball-supported overlay dentures were simulated using SolidWorks, NURBS, and ANSYS Workbench. Loads A (60 N) and B (60 N) were exerted, respectively, in protrusive and laterotrusive motions, on second molar mesial, first molar mesial, and first premolar. The strain distribution patterns were assessed on (1) implant tissue, (2) first implant-bone, and (3) second implant-bone interfaces. Protrusive: Strain was mostly detected in the apical of the fixtures and least in the cervical when bar design was used. On the nonworking side, however, strain was higher in the cervical and lower in the apical compared with the working side implant. Laterotrusive: The strain values were closely similar in the two designs. It seems that both designs are acceptable in terms of stress distribution, although a superior pattern is associated with the application of bar design in protrusive motion.

  13. Oxygen transfer in human carotid artery bifurcation

    Institute of Scientific and Technical Information of China (English)

    Z.G.Zhang; Y.B.Fan; X.Y.Deng

    2007-01-01

    Arterial bifurcations are places where blood flow may be disturbed and slow recirculation flow may occur.To reveal the correlation between local oxygen transfer and atherogenesis, a finite element method was employed to simulate the blood flow and the oxygen transfer in the human carotid artery bifurcation. Under steady-state flow conditions, the numerical simulation demonstrated a variation in local oxygen transfer at the bifurcation, showing that the convective condition in the disturbed flow region may produce uneven local oxygen transfer at the blood/wall interface.The disturbed blood flow with formation of slow eddies in the carotid sinus resulted in a depression in oxygen supply to the arterial wall at the entry of the sinus, which in turn may lead to an atherogenic response of the arterial wall, and contribute to the development of atherosclerotic stenosis there.

  14. Peripheral arterial line (image)

    Science.gov (United States)

    A peripheral arterial line is a small, short plastic catheter placed through the skin into an artery of the arm or leg. The purpose of a peripheral arterial line is to allow continuous monitoring of ...

  15. Astrocytic tumour grading: a comparative study of three-dimensional pseudocontinuous arterial spin labelling, dynamic susceptibility contrast-enhanced perfusion-weighted imaging, and diffusion-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Hua-Feng [302 Hospital of Chinese People' s Liberation Army, Department of Radiology, Beijing (China); Chen, Zhi-Ye; Wang, Yu-Lin; Wang, Yan; Ma, Lin [People' s Liberation Army General Hospital, Department of Radiology, Beijing (China); Lou, Xin [People' s Liberation Army General Hospital, Department of Radiology, Beijing (China); University of California, Department of Neurology, Los Angeles, CA (United States); Gui, Qiu-Ping [People' s Liberation Army General Hospital, Department of Pathology, Beijing (China); Shi, Kai-Ning; Zhou, Zhen-Yu; Zheng, Dan-Dan [General Electric Healthcare (China) Co., Ltd., Beijing; Wang, Danny J.J. [University of California, Department of Neurology, Los Angeles, CA (United States)

    2015-12-15

    We hypothesized that three-dimensional pseudocontinuous arterial spin labelling (pCASL) may have similar efficacy in astrocytic tumour grading as dynamic susceptibility contrast-enhanced perfusion-weighted imaging (DSC-PWI), and the grading accuracy may be further improved when combined with apparent diffusion coefficient (ADC) values. Forty-three patients with astrocytic tumours were studied using diffusion weighted imaging (DWI), pCASL, and DSC-PWI. Histograms of ADC and normalized tumour cerebral blood flow values (nCBF on pCASL and nrCBF on DSC-PWI) were measured and analyzed. The mean 10 % ADC value was the DWI parameter that provided the best differentiation between low-grade astrocytoma (LGA) and high-grade astrocytoma (HGA). The nCBF and nrCBF (1.810 ± 0.979 and 2.070 ± 1.048) in LGA were significantly lower than those (4.505 ± 2.270 and 5.922 ± 2.630) in HGA. For differentiation between LGA and HGA, the cutoff values of 0.764 x 10{sup -3} mm{sup 2}/s for mean 10 % ADC, 2.374 for nCBF, and 3.464 for nrCBF provided the optimal accuracy (74.4 %, 86.1 %, and 88.6 %, respectively). Combining the ADC values with nCBF or nrCBF could further improve the grading accuracy to 97.7 % or 95.3 %, respectively. pCASL is an alternative to DSC-PWI for astrocytic tumour grading. The combination of DWI and contrast-free pCASL offers a valuable choice in patients with risk factors. (orig.)

  16. Comparing the Use of Uterine Artery Embolization to Gonadotropin-Releasing Hormone Agonists in Shrinking Fibroid Size: A Pilot Study in Kazakhstan

    Directory of Open Access Journals (Sweden)

    Balkenzhe Imankulova

    2015-09-01

    Full Text Available Introduction: Uterine fibroids are the most common benign tumor in women in Kazakhstan. In the past two decades, endoscopic surgery has played an important role in the development of gynecologic surgery, particularly in the treatment of uterine fibroids. The goal of this paper is to evaluate whether uterine artery embolization (UAE or gonadotropin-releasing hormone agonists (GnRHa prior to myomectomy was more effective in decreasing fibroid size and improving surgical outcomes in a pilot study of women in Kazakhstan.Methods: This pilot investigation included 24 patients separated into 2 groups: medication group (pre-treatment with GnRHa – 13 patients and embolization group (pre-treatment with UAE – 11 patients. All patients had uterine fibroids, 3-10 cm in diameter, and were treated with myomectomy at the National Research Center for Maternal and Child Health, Astana, Kazakhstan. All patient data were obtained by a retrospective medical records review. Descriptive statistics were utilized to characterize participant demographics data. Independent t-tests were used to analyze continuous variables, and Chi-square and Fisher’s exact tests were used where appropriate for count data.Results: The group treated with GnRHa had an operating time of 40±10 minutes longer than the group treated with UAE, due to the peri-operative difficulties encountered by surgeons in detecting the layer between the myometrium and fibroid capsule. The group treated with UAE experienced better patient outcomes (less blood loss, less surgical time, and reduced use of anesthesia and was a technically easier surgery due to visible differences in uterine layers.Conclusions: Despite the fact that both treatments (GnRHa and UAE were effective for fibroid shrinking, embolization resulted in more optimal surgical time and improved patient outcomes. Results of this pilot study need to be confirmed in a randomized clinical trial, specifically focused on Kazakhstan and the

  17. Comparative analysis of umbilical artery and middle cerebral artery in fetus with cord around neck%脐绕颈胎儿脐动脉及大脑中动脉血流动力学指标的比较分析

    Institute of Scientific and Technical Information of China (English)

    解婷婷; 范雪梅

    2011-01-01

    Objective: To analyze of the dynamic parameter umbilical artery and middle cerebral artery of fetus with the umbilical cord around neck to provide objective proofs diagnosing intrauterine fetal anoxia.Methods: To compare umbilical artery(UA) with middle cerebral artery's (MCA's), Doppler parameter was used in 200 healthy cases and 209 cases with cord around neck, taking pulse index ( PI), resistance index (RI) and the peak-systolic/diastolic ratio(S/D) as analysis target.Results: In the normal group, the PI, RI and S/D of UA and MCA were negatively correlated with ages of women.In the cord around neck group, the PI, RI and S/D of UA were increased significantly, the PI, RI and S/D of MCA were decreased significantly.PI, RI and S/D of the UA and MCA in the two groups had significant differences.Conclusion: Before we deliver a baby, the blood flow of UA and MCA of the fetus should be monitored in order to know the fetal placenta circulation and the fetal brain circulation, thus to prevent intrauterine fetal anoxia from happening.%目的:分析脐带绕颈胎儿脐动脉和大脑中动脉血流动力学参数,为临床判断宫内缺氧提供客观依据.方法:比较彩色多普勒超声检测200例正常妊娠胎儿和209例脐带绕颈胎儿脐动脉(UA)及大脑中动脉(MCA)血液动力学指标,以搏动指数(PI)、阻力指数(RI)、收缩期峰值/舒张期峰值(S/D)为分析指标.结果:正常妊娠胎儿UA和MCA的PI、RI、S/D与孕年呈负相关,脐带绕颈胎儿UA阻力指数增高明显,而MCA阻力指数降低显著.两组UA和MCA的PI、RI、S/D有显著性差异.结论:产前监测脐带绕颈胎儿的UA、MCA血流指数,可以了解胎儿胎盘循环和颅脑循环状态,预测胎儿宫内血氧状况,对了解胎儿血循环状况和及时预防胎儿宫内窘迫具有实用价值.

  18. Renal Artery Stent Outcomes

    Science.gov (United States)

    Murphy, Timothy P.; Cooper, Christopher J.; Matsumoto, Alan H.; Cutlip, Donald E.; Pencina, Karol M.; Jamerson, Kenneth; Tuttle, Katherine R.; Shapiro, Joseph I.; D’Agostino, Ralph; Massaro, Joseph; Henrich, William; Dworkin, Lance D.

    2016-01-01

    BACKGROUND Multiple randomized clinical trials comparing renal artery stent placement plus medical therapy with medical therapy alone have not shown any benefit of stent placement. However, debate continues whether patients with extreme pressure gradients, stenosis severity, or baseline blood pressure benefit from stent revascularization. OBJECTIVES The study sought to test the hypothesis that pressure gradients, stenosis severity, and/or baseline blood pressure affects outcomes after renal artery stent placement. METHODS Using data from 947 patients with a history of hypertension or chronic kidney disease from the largest randomized trial of renal artery stent placement, the CORAL (Cardiovascular Outcomes in Renal Atherosclerotic Lesions) study, we performed exploratory analyses to determine if subsets of patients experienced better outcomes after stent placement than the overall cohort. We examined baseline stenosis severity, systolic blood pressure, and translesion pressure gradient (peak systolic and mean) and performed interaction tests and Cox proportional hazards analyses for the occurrence of the primary endpoint through all follow-up, to examine the effect of these variables on outcomes by treatment group. RESULTS There were no statistically significant differences in outcomes based on the examined variables nor were there any consistent nonsignificant trends. CONCLUSIONS Based on data from the CORAL randomized trial, there is no evidence of a significant treatment effect of the renal artery stent procedure compared with medical therapy alone based on stenosis severity, level of systolic blood pressure elevation, or according to the magnitude of the transstenotic pressure gradient. (Benefits of Medical Therapy Plus Stenting for Renal Atherosclerotic Lesions [CORAL]; NCT00081731) PMID:26653621

  19. Noninvasive pulse wave analysis for the determination of central artery stiffness

    DEFF Research Database (Denmark)

    Wittrock, Marc; Scholze, Alexandra; Compton, Friederike;

    2009-01-01

    Central artery stiffness predicts cardiovascular structural damage and clinical outcome. It is controversial whether central artery stiffness can be determined by noninvasive measurements. We compared noninvasive determination of central artery stiffness obtained from applanation tonometry of the...

  20. Convergence acceleration for partitioned simulations of the fluid-structure interaction in arteries

    Science.gov (United States)

    Radtke, Lars; Larena-Avellaneda, Axel; Debus, Eike Sebastian; Düster, Alexander

    2016-06-01

    We present a partitioned approach to fluid-structure interaction problems arising in analyses of blood flow in arteries. Several strategies to accelerate the convergence of the fixed-point iteration resulting from the coupling of the fluid and the structural sub-problem are investigated. The Aitken relaxation and variants of the interface quasi-Newton -least-squares method are applied to different test cases. A hybrid variant of two well-known variants of the interface quasi-Newton-least-squares method is found to perform best. The test cases cover the typical boundary value problem faced when simulating the fluid-structure interaction in arteries, including a strong added mass effect and a wet surface which accounts for a large part of the overall surface of each sub-problem. A rubber-like Neo Hookean material model and a soft-tissue-like Holzapfel-Gasser-Ogden material model are used to describe the artery wall and are compared in terms of stability and computational expenses. To avoid any kind of locking, high-order finite elements are used to discretize the structural sub-problem. The finite volume method is employed to discretize the fluid sub-problem. We investigate the influence of mass-proportional damping and the material model chosen for the artery on the performance and stability of the acceleration strategies as well as on the simulation results. To show the applicability of the partitioned approach to clinical relevant studies, the hemodynamics in a pathologically deformed artery are investigated, taking the findings of the test case simulations into account.

  1. Systematic comparison of the effectiveness of radial artery and saphenous vein or right internal thoracic artery coronary bypass grafts in non-left anterior descending coronary arteries

    Institute of Scientific and Technical Information of China (English)

    Xiang HU; Qiang ZHAO

    2011-01-01

    Coronary artery bypass grafting surgery is increasingly being carried out on patients with multi-vessel coronary artery disease, but the best grafting candidate for non-left antetior descending coronary arteries is unclear.This research sought to systematically compare the efficacies and safeties of coronary bypass with radial artery and other available grafts. A systematic literature retrieval was performed for all clinical trials comparing the outcomes of coronary artery bypass surgery with radial artery and other grafts in PubMed, EMBASE, and the Cochrane Library.Seven eligible clinical studies, comparing radial artery and great saphenous vein grafts, were found between 1966 and 2010: one prospective non-randomized and six prospective randomized trials. The pooling analysis obtained a relative risk of 0.507 (P<0.05) of graft occlusion in radial arteries compared with great saphenous veins. There was a significantly lower infection rate in arms (i.e., harvest sites for radial arteries) relative to legs (harvest sites for veins), with a pooled relative risk of 0.140 (P<0.05). From the reports on mortality after follow-up ranging from one year to six years,there was no significant difference in mortality between the two graft types (P=0.927). In addition, four cohort controlled trials for radial and right internal thoracic artery grafts were included. The radial graft was associated with less cardiac related events relative to the right intemal thoracic artery graft (P=0.014), but with comparable mortality and comparable rates of repeat percutaneous transluminal coronary angioplasty. Subjects with radial arteries seemed to have a lower occlusion rate and a lower graft harvest site infection rate than those with great saphenous veins. Moreover there were fewer cardiac related events with radial arteries relative to the right internal thoracic artery grafts. More studies are needed to confirm these findings concerning the favorable outcomes of coronary artery

  2. Comparative study on image quality of two different periods of pulmonary artery CTA scanning%两期不同肺动脉CT血管造影术扫描的影像质量对比研究

    Institute of Scientific and Technical Information of China (English)

    黄迪开; 谭莉平; 陆建常; 罗城

    2013-01-01

    Objective To compare the image quality of 16-slice spiral CT angiography in pulmonary artery(CTPA) for pulmonary embolism(PE) with two ways,including intelligent tracking trigger scanning and delay scan,and to confirm its clinical application value and several CTPA techniques.Methods Thirty-four PE patients were performed CTPA with routine scan,then intelligent tracking trigger scanning and delay scan two lung CTA enhancement scanning.All image data were record,including CT features,displayed rate of different pulmonary artery,and were statistically analyzed.Results The direct signs of pulmonary embolism and image quality in two aspects of intelligent tracking trigger scanning were better than the delay scanning(16-21 s).Two scan mode for indirect signs and the trunk of the pulmonary artery,right and left pulmonary artery,leaf and segmental pulmonary arteries display rate were the same,with no significant difference.Conclusion Intelligent tracking trigger scanning can precisely control the scan delay time,so its image quality is better than the delay scanning.%目的 对16层螺旋CT肺动脉造影(CTPA)在诊断肺动脉栓塞(PE)时应用智能追踪触发扫描和延时扫描所得的影像质量进行对比分析,探讨CTPA的临床应用价值和技术要点.方法 对34例PE患者均采用肺部平扫后,再行智能追踪触发扫描和延时扫描两期肺部CTPA增强扫描,所有的影像资料包括CT征象、图像质量、各级肺动脉的显示率等方面进行综合性分析并做好记录,对其结果进行统计学分析.结果 两者在PE直接征象中显示的病灶数方面与图像质量优、良这两个等级的总数方面,智能追踪触发扫描均优于延时扫描(16~21 s).两种扫描方式对于PE的间接征象和肺动脉主干、左右肺动脉、叶及段肺动脉显示率相同,无明显差别.结论 智能追踪触发扫描可以精确控制延迟扫描时间,图像质量明显优于延时扫描.

  3. Finite length Taylor Couette flow

    Science.gov (United States)

    Streett, C. L.; Hussaini, M. Y.

    1987-01-01

    Axisymmetric numerical solutions of the unsteady Navier-Stokes equations for flow between concentric rotating cylinders of finite length are obtained by a spectral collocation method. These representative results pertain to two-cell/one-cell exchange process, and are compared with recent experiments.

  4. Critical Phenomena in Finite Systems

    CERN Document Server

    Bonasera, A; Chiba, S

    2001-01-01

    We discuss the dynamics of finite systems within molecular dynamics models. Signatures of a critical behavior are analyzed and compared to experimental data both in nucleus-nucleus and metallic cluster collisions. We suggest the possibility to explore the instability region via tunneling. In this way we can obtain fragments at very low temperatures and densities. We call these fragments quantum drops.

  5. Independent component analysis applied to pulse oximetry in the estimation of the arterial oxygen saturation (SpO2) - a comparative study

    DEFF Research Database (Denmark)

    Jensen, Thomas; Duun, Sune Bro; Larsen, Jan

    2009-01-01

    ), and Mean Field ICA (ICAMF). The signal processing includes pre-processing bandpass filtering to eliminate noise, and post-processing by calculating the SpO2. The algorithms are compared to the commercial state-of-the-art algorithm Discrete Saturation Transform (DST) by Masimo Corporation...

  6. Prevalence of eight putative periodontal pathogens in atherosclerotic plaque of coronary artery disease patients and comparing them with noncardiac subjects: A case-control study

    Directory of Open Access Journals (Sweden)

    Jaideep Mahendra

    2015-01-01

    Conclusion: It is concluded that CAD subjects had higher prevalence of periodontal pathogens in subgingival biofilms as compared to the non cardiac subjects. Further, the number of bacteria was significantly associated between the subgingival and atherosclerotic plaques of the cardiac patients in south Indian population.

  7. Local effects of atherosclerotic plaque on arterial distensibility.

    Science.gov (United States)

    Giannattasio, C; Failla, M; Emanuelli, G; Grappiolo, A; Boffi, L; Corsi, D; Mancia, G

    2001-11-01

    Hypertension, diabetes, and hypercholesterolemia are characterized by a reduction in arterial distensibility and by accelerated atherosclerosis. Whether arterial stiffening is an inherent feature of these conditions or just the consequence of the atherosclerotic clinical or subclinical lesions is not known, however. Our aim was to obtain information on this issue by directly measuring, in humans, arterial distensibility both at the site of an atherosclerotic lesion and at the proximal normal site. In 10 patients (8 men; mean+/-SEM age, 65.2+/-3.4 years) affected by monolateral hemodynamic significant internal carotid artery stenosis, we measured arterial distensibility (Wall Track System; PIE Medical) bilaterally, both at the internal carotid artery and at the common carotid artery level. In the common carotid artery, measurements were made 3 cm below the bifurcation. In the affected internal carotid artery, measurements were made at the plaque shoulder (wall thickness of 2 mm). Measurements were made in the contralateral internal carotid artery at a symmetrical level. Arterial wall thickness was measured in the same site of arterial distensibility. Arterial distensibility was less in the internal than in the common carotid artery, with a marked reduction at the plaque internal carotid artery level compared with the corresponding contralateral site (-45%, P<0.01). It was also less, however, in the common carotid artery branching into the atherosclerotic internal carotid artery than in the contralateral common carotid artery (-25%, P<0.05). Wall thickness was similar in the 2 common carotid arteries and obviously greater in the affected internal carotid artery than in the contralateral artery. Arterial distensibility was markedly less in the internal carotid artery where there was a plaque compared with the intact contralateral internal carotid artery; it was also less, however, in the common carotid artery of the affected side in comparison with the contralateral

  8. Heart transplantation and arterial elasticity

    Directory of Open Access Journals (Sweden)

    Colvin-Adams M

    2013-12-01

    Full Text Available Monica Colvin-Adams,1 Nonyelum Harcourt,1 Robert LeDuc,2 Ganesh Raveendran,1 Yassir Sonbol,3 Robert Wilson,1 Daniel Duprez11Cardiovascular Division, University of Minnesota, Minneapolis, MN, USA; 2Division of Biostatistics University of Minnesota, Minneapolis, MN, USA; 3Cardiovascular Division, St Luke's Hospital System, Sugar Land, TX, USAObjective: Arterial elasticity is a functional biomarker that has predictive value for cardiovascular morbidity and mortality in nontransplant populations. There is little information regarding arterial elasticity in heart transplant recipients. This study aimed to characterize small (SAE and large (LAE artery elasticity in heart transplant recipients in comparison with an asymptomatic population free of overt cardiovascular disease. A second goal was to identify demographic and clinical factors associated with arterial elasticity in this unique population.Methods: Arterial pulse waveform was registered noninvasively at the radial artery in 71 heart transplant recipients between 2008 and 2010. SAEs and LAEs were derived from diastolic pulse contour analysis. Comparisons were made to a healthy cohort of 1,808 participants selected from our prevention clinic database. Multiple regression analyses were performed to evaluate associations between risk factors and SAE and LAE within the heart transplant recipients.Results: LAE and SAE were significantly lower in heart transplant recipients than in the normal cohort (P <0.01 and P < 0.0001, respectively. Female sex and history of ischemic cardiomyopathy were significantly associated with reduced LAE and SAE. Older age and the presence of moderate cardiac allograft vasculopathy were also significantly associated with reduced SAE. Transplant duration was associated with increased SAE.Conclusion: Heart transplants are associated with peripheral endothelial dysfunction and arterial stiffness, as demonstrated by a significant reduction in SAE and LAE when compared with a

  9. Variational collocation on finite intervals

    Energy Technology Data Exchange (ETDEWEB)

    Amore, Paolo [Facultad de Ciencias, Universidad de Colima, Bernal DIaz del Castillo 340, Colima, Colima (Mexico); Cervantes, Mayra [Facultad de Ciencias, Universidad de Colima, Bernal DIaz del Castillo 340, Colima, Colima (Mexico); Fernandez, Francisco M [INIFTA (Conicet, UNLP), Diag. 113 y 64 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)

    2007-10-26

    In this paper, we study a set of functions, defined on an interval of finite width, which are orthogonal and which reduce to the sinc functions when the appropriate limit is taken. We show that these functions can be used within a variational approach to obtain accurate results for a variety of problems. We have applied them to the interpolation of functions on finite domains and to the solution of the Schroedinger equation, and we have compared the performance of the present approach with others.

  10. Arterial function of carotid and brachial arteries in postmenopausal vegetarians

    Directory of Open Access Journals (Sweden)

    Su T

    2011-08-01

    Full Text Available Ta-Chen Su1, Pao-Ling Torng2, Jiann-Shing Jeng3, Ming-Fong Chen1, Chiau-Suong Liau1,41Division of Cardiology, Department of Internal Medicine, 2Department of Obstetrics and Gynecology, 3Department of Neurology, National Taiwan University Hospital, National Taiwan University College of Medicine, 4Cardiovascular Center, Taipei Buddist Tzu-Chi Hospital, Hsin-Dian, Taipei, TaiwanBackground: Vegetarianism is associated with a lower risk of cardiovascular disease. However, studies of arterial function in vegetarians are limited.Methods: This study investigated arterial function in vegetarianism by comparing 49 healthy postmenopausal vegetarians with 41 age-matched omnivores. The arterial function of the common carotid artery was assessed by carotid duplex, while the pulse dynamics method was used to measure brachial artery distensibility (BAD, compliance (BAC, and resistance (BAR. Fasting blood levels of glucose, lipids, lipoprotein (a, high-sensitivity C-reactive protein, homocysteine, and vitamin B12 were also measured.Results: Vegetarians had significantly lower serum cholesterol, high-density and low-density lipoprotein, and glucose compared with omnivores. They also had lower vitamin B12 but higher homocysteine levels. Serum levels of lipoprotein (a and high-sensitivity C-reactive protein were no different between the two groups. There were no significant differences in carotid beta stiffness index, BAC, and BAD between the two groups even after adjustment for associated covariates. However, BAR was significantly lower in vegetarians than in omnivores. Multiple linear regression analysis revealed that age and pulse pressure were two important determinants of carotid beta stiffness index and BAD. Vegetarianism is not associated with better arterial elasticity.Conclusion: Apparently healthy postmenopausal vegetarians are not significantly better in terms of carotid beta stiffness index, BAC, and BAD, but have significantly decreased BAR than

  11. Original Research: Sickle cell anemia and pediatric strokes: Computational fluid dynamics analysis in the middle cerebral artery.

    Science.gov (United States)

    Rivera, Christian P; Veneziani, Alessandro; Ware, Russell E; Platt, Manu O

    2016-04-01

    Children with sickle cell anemia (SCA) have a high incidence of strokes, and transcranial Doppler (TCD) identifies at-risk patients by measuring blood velocities in large intracerebral arteries; time-averaged mean velocities greater than 200 cm/s confer high stroke risk and warrant therapeutic intervention with blood transfusions. Our objective was to use computational fluid dynamics to alter fluid and artery wall properties, to simulate scenarios causative of significantly elevated arterial blood velocities. Two-dimensional simulations were created and increasing percent stenoses were created in silico, with their locations varied among middle cerebral artery (MCA), internal carotid artery (ICA), and anterior cerebral artery (ACA). Stenoses placed in the MCA, ICA, or ACA generated local increases in velocity, but not sufficient to reach magnitudes > 200 cm/s, even up to 75% stenosis. Three-dimensional reconstructions of the MCA, ICA, and ACA from children with SCA were generated from magnetic resonance angiograms. Using finite element method, blood flow was simulated with realistic velocity waveforms to the ICA inlet. Three-dimensional reconstructions revealed an uneven, internal arterial wall surface in children with SCA and higher mean velocities in the MCA up to 145 cm/s compared to non-SCA reconstructions. There were also greater areas of flow recirculation and larger regions of low wall shear stress. Taken together, these bumps on the internal wall of the cerebral arteries could create local flow disturbances that, in aggregate, could elevate blood velocities in SCA. Identifying cellular causes of these microstructures as adhered blood cells or luminal narrowing due to endothelial hyperplasia induced by disturbed flow would provide new targets to treat children with SCA. The preliminary qualitative results provided here point out the critical role of 3D reconstruction of patient-specific vascular geometries and provide qualitative insight to complex

  12. Sound radiation from finite surfaces

    DEFF Research Database (Denmark)

    Brunskog, Jonas

    2013-01-01

    A method to account for the effect of finite size in acoustic power radiation problem of planar surfaces using spatial windowing is developed. Cremer and Heckl presents a very useful formula for the power radiating from a structure using the spatially Fourier transformed velocity, which combined...... with spatially windowing of a plane waves can be used to take into account the finite size. In the present paper, this is developed by means of a radiation impedance for finite surfaces, that is used instead of the radiation impedance for infinite surfaces. In this way, the spatial windowing is included...... in the radiation formula directly, and no pre-windowing is needed. Examples are given for the radiation efficiency, and the results are compared with results found in the literature....

  13. Second order tensor finite element

    Science.gov (United States)

    Oden, J. Tinsley; Fly, J.; Berry, C.; Tworzydlo, W.; Vadaketh, S.; Bass, J.

    1990-01-01

    The results of a research and software development effort are presented for the finite element modeling of the static and dynamic behavior of anisotropic materials, with emphasis on single crystal alloys. Various versions of two dimensional and three dimensional hybrid finite elements were implemented and compared with displacement-based elements. Both static and dynamic cases are considered. The hybrid elements developed in the project were incorporated into the SPAR finite element code. In an extension of the first phase of the project, optimization of experimental tests for anisotropic materials was addressed. In particular, the problem of calculating material properties from tensile tests and of calculating stresses from strain measurements were considered. For both cases, numerical procedures and software for the optimization of strain gauge and material axes orientation were developed.

  14. Diagnostic value of18F-FDG PET in the assessment of myocardial viability in coronary artery disease:A comparative study with99mTc SPECT and echocar-diography

    Institute of Scientific and Technical Information of China (English)

    Mansour Al Moudi; Zhong-Hua Sun

    2014-01-01

    ObjectiveTo investigate the diagnostic value of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in the as-sessment of myocardial viability in patients with known coronary artery disease (CAD) when compared to99mTc single photon emission computed tomography (SPECT) and echocardiography, with invasive coronary angiography as the gold standard.MethodsThirty patients with diagnosed CAD met the selection criteria, with 10 of them (9 men, mean age 59.5 ± 10.5 years) undergoing all of these imaging proce-dures consisting of SPECT and PET, echocardiography and invasive angiography. Diagnostic sensitivity of these less invasive modalities for detection of myocardial viability was compared to invasive coronary angiography. Inter- and intra-observer agreement was assessed for di-agnostic performance of SPECT and PET.ResultsOf all patients with proven CAD, 50% had triple vessel disease. Diagnostic sensitivity of SPECT, PET and echocardiography was 90%, 100% and 80% at patient-based assessment, respectively. Excellent agreement was achieved between inter-observer and intra-observer agreement of the diagnostic value of SPECT and PET in myocardial viability (k= 0.9). Conclusion18F-FDG PET has high diagnostic value in the assessment of myocardial viability in patients with known CAD when com-pared to SPECT and echocardiography. Further studies based on a large cohort with incorporation of18F-FDG PET into patient management are warranted.

  15. Finite Random Domino Automaton

    CERN Document Server

    Bialecki, Mariusz

    2012-01-01

    Finite version of Random Domino Automaton (FRDA) - recently proposed a toy model of earthquakes - is investigated. Respective set of equations describing stationary state of the FRDA is derived and compared with infinite case. It is shown that for the system of big size, these equations are coincident with RDA equations. We demonstrate a non-existence of exact equations for size N bigger then 4 and propose appropriate approximations, the quality of which is studied in examples obtained within Markov chains framework. We derive several exact formulas describing properties of the automaton, including time aspects. In particular, a way to achieve a quasi-periodic like behaviour of RDA is presented. Thus, based on the same microscopic rule - which produces exponential and inverse-power like distributions - we extend applicability of the model to quasi-periodic phenomena.

  16. Relaxed incremental variational approach for the modeling of damage-induced stress hysteresis in arterial walls.

    Science.gov (United States)

    Schmidt, Thomas; Balzani, Daniel

    2016-05-01

    In this paper, a three-dimensional relaxed incremental variational damage model is proposed, which enables the description of complex softening hysteresis as observed in supra-physiologically loaded arterial tissues, and which thereby avoids a loss of convexity of the underlying formulation. The proposed model extends the relaxed formulation of Balzani and Ortiz [2012. Relaxed incremental variational formulation for damage at large strains with application to fiber-reinforced materials and materials with truss-like microstructures. Int. J. Numer. Methods Eng. 92, 551-570], such that the typical stress-hysteresis observed in arterial tissues under cyclic loading can be described. This is mainly achieved by constructing a modified one-dimensional model accounting for cyclic loading in the individual fiber direction and numerically homogenizing the response taking into account a fiber orientation distribution function. A new solution strategy for the identification of the convexified stress potential is proposed based on an evolutionary algorithm which leads to an improved robustness compared to solely Newton-based optimization schemes. In order to enable an efficient adjustment of the new model to experimentally observed softening hysteresis, an adjustment scheme using a surrogate model is proposed. Therewith, the relaxed formulation is adjusted to experimental data in the supra-physiological domain of the media and adventitia of a human carotid artery. The performance of the model is then demonstrated in a finite element example of an overstretched artery. Although here three-dimensional thick-walled atherosclerotic arteries are considered, it is emphasized that the formulation can also directly be applied to thin-walled simulations of arteries using shell elements or other fiber-reinforced biomembranes.

  17. Simple Finite Jordan Pseudoalgebras

    Directory of Open Access Journals (Sweden)

    Pavel Kolesnikov

    2009-01-01

    Full Text Available We consider the structure of Jordan H-pseudoalgebras which are linearly finitely generated over a Hopf algebra H. There are two cases under consideration: H = U(h and H = U(h # C[Γ], where h is a finite-dimensional Lie algebra over C, Γ is an arbitrary group acting on U(h by automorphisms. We construct an analogue of the Tits-Kantor-Koecher construction for finite Jordan pseudoalgebras and describe all simple ones.

  18. Simple Finite Jordan Pseudoalgebras

    Science.gov (United States)

    Kolesnikov, Pavel

    2009-01-01

    We consider the structure of Jordan H-pseudoalgebras which are linearly finitely generated over a Hopf algebra H. There are two cases under consideration: H = U(h) and H = U(h) # C[Γ], where h is a finite-dimensional Lie algebra over C, Γ is an arbitrary group acting on U(h) by automorphisms. We construct an analogue of the Tits-Kantor-Koecher construction for finite Jordan pseudoalgebras and describe all simple ones.

  19. Handbook of finite fields

    CERN Document Server

    Mullen, Gary L

    2013-01-01

    Poised to become the leading reference in the field, the Handbook of Finite Fields is exclusively devoted to the theory and applications of finite fields. More than 80 international contributors compile state-of-the-art research in this definitive handbook. Edited by two renowned researchers, the book uses a uniform style and format throughout and each chapter is self contained and peer reviewed. The first part of the book traces the history of finite fields through the eighteenth and nineteenth centuries. The second part presents theoretical properties of finite fields, covering polynomials,

  20. Finite Unification: phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Heinemeyer, S; Ma, E; Mondragon, M; Zoupanos, G, E-mail: sven.heinemeyer@cern.ch, E-mail: ma@phyun8.ucr.edu, E-mail: myriarn@fisica.unam.mx, E-mail: george.zoupanos@cern.ch

    2010-11-01

    We study the phenomenological implications of Finite Unified Theories (FUTs). In particular we look at the predictions for the lightest Higgs mass and the s-spectra of two all-loop finite models with SU(5) as gauge group. We also consider a two-loop finite model with gauge group SU(3){sup 3}, which is finite if and only if there are exactly three generations. In this latter model we concetrate here only on the predictions for the third generation of quark masses.

  1. Finite element procedures

    CERN Document Server

    Bathe, Klaus-Jürgen

    2015-01-01

    Finite element procedures are now an important and frequently indispensable part of engineering analyses and scientific investigations. This book focuses on finite element procedures that are very useful and are widely employed. Formulations for the linear and nonlinear analyses of solids and structures, fluids, and multiphysics problems are presented, appropriate finite elements are discussed, and solution techniques for the governing finite element equations are given. The book presents general, reliable, and effective procedures that are fundamental and can be expected to be in use for a long time. The given procedures form also the foundations of recent developments in the field.

  2. Finite Symplectic Matrix Groups

    OpenAIRE

    2011-01-01

    The finite subgroups of GL(m, Q) are those subgroups that fix a full lattice in Q^m together with some positive definite symmetric form. A subgroup of GL(m, Q) is called symplectic, if it fixes a nondegenerate skewsymmetric form. Such groups only exist if m is even. A symplectic subgroup of GL(2n, Q) is called maximal finite symplectic if it is not properly contained in some finite symplectic subgroup of GL(2n, Q). This thesis classifies all conjugacy classes of maximal finite symplectic subg...

  3. Mesenteric artery ischemia

    Science.gov (United States)

    ... medlineplus.gov/ency/article/001156.htm Mesenteric artery ischemia To use the sharing features on this page, please enable JavaScript. Mesenteric artery ischemia occurs when there is a narrowing or blockage ...

  4. Finite length microchannel flow in transitional regime (-Analytical prediction compared with experiment)%有限长度的过渡领域微槽道流动(-分析预测和试验的比较)

    Institute of Scientific and Technical Information of China (English)

    沈青; 蒋建政

    2008-01-01

    In a steady finite length channel of gas flow, analytical expressions of the pressure distribution along the channel axis and of mass flow rate are obtained by the global mass conservation law for continuum and slip flow regimes. In the transitional flow regime a strict kinetic theoretical solution of the channel flow pressure distribution is also provided, when the kinetic theoretical solution of the mass flux for the Poiseuille flow is known, the equation governing the pressure distribution is shown to be the degenerated Reynolds equation transplanted by the senior author from the bearing lubrication problem to the microchannel problem.Analytical expression of the flow mass rate is also obtained and compared with the available experimental data and excellent agreement is obtained.%在连续介质和滑流区有限长度槽道内的稳定气流,通过整体质量守恒规律得到了沿槽道轴向的压力分布和质量流率的分析表达式.在过渡领域区,也提供了槽道流动压力分布的严格的动理学理论解.在Poiseuille流动的质量流率动理学理论解给定的情况下,压力分布的控制方程被证实是被前一作者从轴承润滑问题移植到解微槽道问题的退化Reynolds方程.同时得到了质量流率分析表达式,它们和现有试验数据的比较相符很好.

  5. Estudo comparativo randomizado do implante de Stent de aço inoxidável recoberto por carbono semelhante ao diamante versus não recoberto em pacientes com doença arterial coronariana Randomized comparative study of diamond-like carbon coated stainless steel stent versus uncoated stent implantation in patients with coronary artery disease

    Directory of Open Access Journals (Sweden)

    George César Ximenes Meireles

    2007-04-01

    Full Text Available OBJETIVO: Comparar as taxas de reestenose e de eventos cardíacos maiores em um e seis meses pós-implante de stents recobertos com CSD com os não-recobertos. MÉTODOS: Estudo comparativo, prospectivo, randomizado, de 180 pacientes com diagnóstico de insuficiência coronária, submetidos a implante de stent recoberto com CSD (Phytis® ou stent não-recobertos (Penta®, no período de janeiro de 2003 a julho de 2004. Foram critérios de inclusão: lesão de novo com porcentual de estenose em diâmetro > 50% em artéria coronária com diâmetro de referência > 2,5 mm e OBJECTIVE: To compare restenosis and major cardiac event rates at one and six months after DLC-coated stent implantation with those of uncoated stents. METHODS: Randomized, prospective, comparative study of 180 patients with coronary insufficiency undergoing DLC coated stent (Phytis™ or uncoated stent (Penta™ implantation, from January, 2003 to July, 2004. Inclusion criteria were: de novo lesion with >50% diameter stenosis in a coronary artery with reference diameter > 2,5 mm and < 4 mm, and length < 20 mm. Exclusion criteria were: left main coronary artery and bifurcation lesions, chronic total occlusion, and in-stent restenosis. RESULTS: Clinical and angiographic baseline characteristics of the groups were similar. Procedural success was achieved in 98.9% of the patients in both groups. One cardiac death occurred in each group during hospitalization. Reference diameter and acute gain were greater in the Penta™ group (3.21±0.37 mm vs. 3.34±0.8 mm, p=0.02 and 2.3±0.5 vs. 2.49±0.5, p=0.009, respectively. Angiographic follow-up at six months showed similar rates of restenosis (24.3% vs. 21.8%, p=0.84 and of major cardiac events (16.8% vs. 17.5%, p=1. CONCLUSION: DLC coated stents did not provide better outcomes in relation to uncoated stents.

  6. Upper limb arterial thromboembolism

    DEFF Research Database (Denmark)

    Andersen, L V; Lip, Gregory Y.H.; Lindholt, J S;

    2013-01-01

    The aim of this review is to focus on risk factors, risk-modifying drugs and prognosis for upper limb arterial thromboembolism, and the relationship between upper limb arterial thromboembolism and atrial fibrillation (AF).......The aim of this review is to focus on risk factors, risk-modifying drugs and prognosis for upper limb arterial thromboembolism, and the relationship between upper limb arterial thromboembolism and atrial fibrillation (AF)....

  7. Computational modeling of hypertensive growth in the human carotid artery

    Science.gov (United States)

    Sáez, Pablo; Peña, Estefania; Martínez, Miguel Angel; Kuhl, Ellen

    2014-06-01

    Arterial hypertension is a chronic medical condition associated with an elevated blood pressure. Chronic arterial hypertension initiates a series of events, which are known to collectively initiate arterial wall thickening. However, the correlation between macrostructural mechanical loading, microstructural cellular changes, and macrostructural adaptation remains unclear. Here, we present a microstructurally motivated computational model for chronic arterial hypertension through smooth muscle cell growth. To model growth, we adopt a classical concept based on the multiplicative decomposition of the deformation gradient into an elastic part and a growth part. Motivated by clinical observations, we assume that the driving force for growth is the stretch sensed by the smooth muscle cells. We embed our model into a finite element framework, where growth is stored locally as an internal variable. First, to demonstrate the features of our model, we investigate the effects of hypertensive growth in a real human carotid artery. Our results agree nicely with experimental data reported in the literature both qualitatively and quantitatively.

  8. Designs and finite geometries

    CERN Document Server

    1996-01-01

    Designs and Finite Geometries brings together in one place important contributions and up-to-date research results in this important area of mathematics. Designs and Finite Geometries serves as an excellent reference, providing insight into some of the most important research issues in the field.

  9. On finitely recursive programs

    CERN Document Server

    Baselice, Sabrina; Criscuolo, Giovanni

    2009-01-01

    Disjunctive finitary programs are a class of logic programs admitting function symbols and hence infinite domains. They have very good computational properties, for example ground queries are decidable while in the general case the stable model semantics is highly undecidable. In this paper we prove that a larger class of programs, called finitely recursive programs, preserves most of the good properties of finitary programs under the stable model semantics, namely: (i) finitely recursive programs enjoy a compactness property; (ii) inconsistency checking and skeptical reasoning are semidecidable; (iii) skeptical resolution is complete for normal finitely recursive programs. Moreover, we show how to check inconsistency and answer skeptical queries using finite subsets of the ground program instantiation. We achieve this by extending the splitting sequence theorem by Lifschitz and Turner: We prove that if the input program P is finitely recursive, then the partial stable models determined by any smooth splittin...

  10. Transradial artery coronary angioplasty.

    Science.gov (United States)

    Kiemeneij, F; Laarman, G J; de Melker, E

    1995-01-01

    This study explored the feasibility and safety of percutaneous coronary balloon angioplasty (PTCA) with miniaturized PTCA equipment via the radial artery. Coronary angioplasty (PTCA) via the femoral or brachial arteries may be associated with rare vascular complications such as bleeding and damage to the artery and adjacent structures. It was postulated that PTCA via the radial artery with miniaturized angioplasty equipment is feasible and that no major puncture site-related complications occur because hemostasis is obtained easily and because no major structures are near the radial artery. With double blood supply to the hand, radial artery occlusion is well tolerated. In 100 patients with collateral blood supply to the right hand, PTCA was attempted with 6F guiding catheters and rapid-exchange balloon catheters for exertional angina (87 patients) or nonexertional angina (13 patients). Angioplasty was attempted in 122 lesions (type A n = 67 [55%], Type B n = 37 [30%], and type C n = 18 [15%]). Pre- and post-PTCA computerized quantitative coronary analysis was performed. Radial artery function and structure were assessed clinically and with Doppler and two-dimensional ultrasound on the day of discharge. Coronary catheterization via the radial artery was successful in 94 patients (94%). The 6 remaining patients had successful PTCA via the femoral artery (n = 5) or the brachial artery (n = 1). Procedural success (120 of 122 lesions) was achieved in 92 patients (98%) via the radial artery and in 98 patients of the total study population.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Percutaneous coronary intervention versus coronary-artery bypass grafting for severe coronary artery disease

    NARCIS (Netherlands)

    P.W.J.C. Serruys (Patrick); M-C. Morice (Marie-Claude); A.P. Kappetein (Arie Pieter); A. Colombo (Antonio); D.R. Holmes Jr (David); M.J. Mack (Michael); E. Stahle (Elisabeth); T.E. Feldman (Ted); M.J.B.M. van den Brand (Marcel); E.J. Bass (Eric); N. van Dyck (Nic); K. Leadly (Katrin); K.D. Dawkins (Keith); F.W. Mohr (Friedrich)

    2009-01-01

    textabstractBACKGROUND Percutaneous coronary intervention (PCI) involving drug-eluting stents is increasingly used to treat complex coronary artery disease, although coronary-artery bypass grafting (CABG) has been the treatment of choice historically. Our trial compared PCI and CABG for treating pat

  12. Percutaneous transluminal angioplasty of the superficial femoral artery by retrograde catheterization via the popliteal artery

    DEFF Research Database (Denmark)

    Tønnesen, K H; Sager, P; Karle, A;

    1988-01-01

    We report the results of 50 angioplasty procedures via the popliteal artery. A 3-year follow-up including control of blood pressures at ankle and toe levels show results comparable to reports in the literature. This new approach for angioplasty of the superficial femoral artery and eventually...

  13. Effect of Stent Radial Force on Stress Pattern After Deployment: A Finite Element Study

    Science.gov (United States)

    Borghi, Alessandro; Murphy, Olive; Bahmanyar, Reza; McLeod, Chris

    2014-07-01

    The present article presents a method for assessing the radial stiffness of nitinol stents. An idealized stent model was created, and its radial stiffness was calculated by means of finite element modeling. The calculations were validated against experimental measurements. The variation of radial stiffness with geometrical dimensions was calculated, and the effect of increasing radial stiffness on endovascular deployment was analyzed. Peak tensile and compressive stresses as well as stent penetration were calculated in the case of an idealized pulmonary artery model having realistic dimensions as well as stiffness. The results of stress calculations were compared with a second set of simulations, where an idealized behavior of the stent (uniform expansion to a theoretical contact diameter) was modeled. The results show how in reality nitinol stents behave in a non-ideal way, having a non-uniform expansion and exerting non-uniform pressure on the contact areas with the artery. Such non-ideality decreases though with the increase in radial stiffness. The radial force alone may be insufficient in describing the stent-artery interaction, and numerical modeling proves to be necessary for capturing such complexity.

  14. Acute occlusion of the left subclavian artery with artery dissection

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Subclavian steal syndrome is cerebral or brain stem ischemia resulting from diversion of blood flow from the basilar artery to the subclavian artery, which is caused by occlusive disease of either the subclavian artery or the innominate artery before they branch off at the vertebral artery. In the patients with subclavian steal syndrome the subclavian artery is fed by retrograde flow from the vertebral artery via the carotids and the circle of Willis.

  15. Anatomic study of the dorsal arterial system of the hand Estudo anatômico do sistema arterial dorsal da mão

    OpenAIRE

    Marcelo Rosa de Rezende; Rames Mattar Júnior; Álvaro Baik Cho; Oswaldo Hideo Hasegawa; Samuel Ribak

    2004-01-01

    Historically, the dorsal arterial system of the hand received less attention than the palmar system. The studies concerning dorsal arterial anatomy present some controversies regarding the origin and presence of the dorsal metacarpal artery branches. Knowledge of the anatomy of dorsal metacarpal arteries is especially applied in the surgical planning for flaps taken from the dorsum of the hand. The purpose of this study is to analyze the arterial anatomy of the dorsum of the hand, compare our...

  16. Finite-volume scheme for anisotropic diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Es, Bram van, E-mail: bramiozo@gmail.com [Centrum Wiskunde & Informatica, P.O. Box 94079, 1090GB Amsterdam (Netherlands); FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, The Netherlands" 1 (Netherlands); Koren, Barry [Eindhoven University of Technology (Netherlands); Blank, Hugo J. de [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, The Netherlands" 1 (Netherlands)

    2016-02-01

    In this paper, we apply a special finite-volume scheme, limited to smooth temperature distributions and Cartesian grids, to test the importance of connectivity of the finite volumes. The area of application is nuclear fusion plasma with field line aligned temperature gradients and extreme anisotropy. We apply the scheme to the anisotropic heat-conduction equation, and compare its results with those of existing finite-volume schemes for anisotropic diffusion. Also, we introduce a general model adaptation of the steady diffusion equation for extremely anisotropic diffusion problems with closed field lines.

  17. Finite elements and approximation

    CERN Document Server

    Zienkiewicz, O C

    2006-01-01

    A powerful tool for the approximate solution of differential equations, the finite element is extensively used in industry and research. This book offers students of engineering and physics a comprehensive view of the principles involved, with numerous illustrative examples and exercises.Starting with continuum boundary value problems and the need for numerical discretization, the text examines finite difference methods, weighted residual methods in the context of continuous trial functions, and piecewise defined trial functions and the finite element method. Additional topics include higher o

  18. Drug delivery patterns for different stenting techniques in coronary bifurcations: a comparative computational study.

    Science.gov (United States)

    Cutrì, Elena; Zunino, Paolo; Morlacchi, Stefano; Chiastra, Claudio; Migliavacca, Francesco

    2013-08-01

    The treatment of coronary bifurcation lesions represents a challenge for the interventional cardiologists due to the lower rate of procedural success and the higher risk of restenosis. The advent of drug-eluting stents (DES) has dramatically reduced restenosis and consequently the request for re-intervention. The aim of the present work is to provide further insight about the effectiveness of DES by means of a computational study that combines virtual stent implantation, fluid dynamics and drug release for different stenting protocols currently used in the treatment of a coronary artery bifurcation. An explicit dynamic finite element model is developed in order to obtain realistic configurations of the implanted devices used to perform fluid dynamics analysis by means of a previously developed finite element method coupling the blood flow and the intramural plasma filtration in rigid arteries. To efficiently model the drug release, a multiscale strategy is adopted, ranging from lumped parameter model accounting for drug release to fully 3-D models for drug transport to the artery. Differences in drug delivery to the artery are evaluated with respect to local drug dosage. This model allowed to compare alternative stenting configurations (namely the Provisional Side Branch, the Culotte and the Inverted Culotte techniques), thus suggesting guidelines in the treatment of coronary bifurcation lesions and addressing clinical issues such as the effectiveness of drug delivery to lesions in the side branch, as well as the influence of incomplete strut apposition and overlapping stents.

  19. Bilateral accessory thoracodorsal artery.

    Science.gov (United States)

    Natsis, Konstantinos; Totlis, Trifon; Tsikaras, Prokopios; Skandalakis, Panagiotis

    2006-09-01

    The subscapular artery arises from the third part of the axillary artery and gives off the circumflex scapular and the thoracodorsal arteries. Although anatomical variations of the axillary artery are very common, the existence of a unilateral accessory thoracodorsal artery has been described in the literature only once. There are no reports of bilateral accessory thoracodorsal artery, in the literature. In the present study, a bilateral accessory thoracodorsal artery, originating on either side of the third part of the axillary artery, is described in a 68-year-old female cadaver. All the other branches of the axillary artery had a typical origin, course, distribution and termination. This extremely rare anatomical variation apart from the anatomical importance also has clinical significance for surgeons in this area. Especially, during the dissection or mobilization of the latissimus dorsi that is partly used for coverage problems in many regions of the body and also in dynamic cardiomyoplasty, any iatrogenic injury of this accessory artery may result in ischemia and functional loss of the graft.

  20. Quarks in finite nuclei

    CERN Document Server

    Guichon, P A M; Thomas, A W

    1996-01-01

    We describe the development of a theoretical description of the structure of finite nuclei based on a relativistic quark model of the structure of the bound nucleons which interact through the (self-consistent) exchange of scalar and vector mesons.

  1. Advanced finite element technologies

    CERN Document Server

    Wriggers, Peter

    2016-01-01

    The book presents an overview of the state of research of advanced finite element technologies. Besides the mathematical analysis, the finite element development and their engineering applications are shown to the reader. The authors give a survey of the methods and technologies concerning efficiency, robustness and performance aspects. The book covers the topics of mathematical foundations for variational approaches and the mathematical understanding of the analytical requirements of modern finite element methods. Special attention is paid to finite deformations, adaptive strategies, incompressible, isotropic or anisotropic material behavior and the mathematical and numerical treatment of the well-known locking phenomenon. Beyond that new results for the introduced approaches are presented especially for challenging nonlinear problems.

  2. Estudo comparativo entre efedrina e etilefrina como vasopressor para correção da hipotensão arterial materna em cesarianas eletivas com raquianestesia Estudio comparativo entre efedrina y etilefrina como vasopresor para correción de la hipotensión materna en cesáreas electivas con raquianestesia Ephedrine and etilefrine as vasopressor to correct maternal arterial hypotension during elective cesarean section under spinal anesthesia. Comparative study

    Directory of Open Access Journals (Sweden)

    Sérgio D. Belzarena

    2006-06-01

    grupos iguales. Todas recibieron raquianestesia con bupivacaína, fentanil y morfina. Se les midió la presión arterial no invasiva y la frecuencia cardiaca. Los recién nacidos fueron evaluados con el índice de Apgar. La incidencia de hipotensión arterial, la cantidad de vasopresor necesaria para corrección y los efectos adversos fueron registrados. RESULTADOS: Ocurrió hipotensión arterial materna con frecuencia en los dos grupos, siendo un 68% del grupo etilefrina y un 63% del grupo efedrina. En la mayoría de las embrazadas, se corrigió con la primera dosis del vasopresor, sin diferencia entre los grupos (66% etilefrina, 58% efedrina. La hipotensión arterial necesitó dos o más dosis de vasopresor para ser corregida o se registró hipertensión reactiva en pocas pacientes (un 24% y un 10% del grupo etilefrina y 34% y 8% del grupo efedrina, respectivamente, sin diferencia estadística significativa. No hubo diferencia en los efectos adversos y en las pruebas de los recién nacidos. CONCLUSIONES: Con el método de administración empleado y con las dosis de vasopresor seleccionadas no hubo diferencia entre la efedrina y la etilefrina cuando se utilizaron para corregir la hipotensión arterial materna en cesáreas con raquianestesia.BACKGROUND AND OBJECTIVES: Ephedrine is the most popular vasopressor for obstetrics and etilefrine is widely used in regional anesthesia. This study aimed at comparing ephedrine and etilefrine to correct maternal arterial hypotension during elective Cesarean section under spinal anesthesia. METHODS: Participated in this study 120 pregnant patients who were randomly distributed in two equal groups. All patients received spinal anesthesia with bupivacaine, fentanyl and morphine. Noninvasive blood pressure and heart rate were monitored. Neonates were evaluated by the Apgar score. The incidence of hypotension, the amount of vasopressor needed to correct it and adverse effects were recorded. RESULTS: Maternal hypotension was similar in

  3. Comparative finite element analysis of fixations for posterior malleolar fracture%后踝骨折内固定方法的有限元模拟比较研究

    Institute of Scientific and Technical Information of China (English)

    金丹; 付苏; 梅刚; 邹振吕; 刘松; 王尚冲; 刘军

    2014-01-01

    Objective To compare the tube plate,T-plate and screws in fixation of posterior malleolar fracture in terms of biomechanical stability.Methods The CT data of the ankle obtained from a normal male volunteer was used to make a three-dimensional reconstruction by software mimics 14.0 and geomagic 2012.After we built a three-dimensional finite element model of the ankle along with its stimulated ligaments in software ANSYS,the validity of the model was verified.The model of posterior malleolar fracture was cut from the posteromedial point of the tibia to the one-fourth point of the distance from the posterior to the anterior margin in the software Solidworks 2012.Models of screws,1/4 tube plate and T-plate were also constructed in Solidworks 2012.According to the established method in the literature,2 screws,a 1/4 tube plate and a T-plate were applied respectively.Under the same neutral weight bearing,the flexion and external loadings,the fragmental displacement,the stresses of fracture and fixation were calculated by finite element analysis.Results Under neutral or external loading,T-plate fixation caused the smallest fragmental displacement compared with the other 2 fixations and the 2 plate fixations caused a smaller displacement in Z-axis under neutral loading than screws fixation.However,similar displacements were identified in all fixations under flexion loading.Under all loading conditions,excessive concentration of the stress was not observed.Conclusions T-plate shows a better biomechanical stability than 1/4 tube-plate and screws while plating reduces the upward displacement than screws.All the 3 fixations show no obvious excessive concentration of the stress.%目的 使用有限元法分析比较螺钉、管型钢板、3孔T型钢板固定治疗后踝骨折的生物力学稳定性.方法 取1名23岁男性健康志愿者的足踝CT数据进行三维重建,建立带有周围韧带的踝关节有限元模型并进行有效性验证,将模型导入Solidworks软

  4. A Finite Element Model for Mixed Porohyperelasticity with Transport, Swelling, and Growth.

    Science.gov (United States)

    Armstrong, Michelle Hine; Buganza Tepole, Adrián; Kuhl, Ellen; Simon, Bruce R; Vande Geest, Jonathan P

    2016-01-01

    The purpose of this manuscript is to establish a unified theory of porohyperelasticity with transport and growth and to demonstrate the capability of this theory using a finite element model developed in MATLAB. We combine the theories of volumetric growth and mixed porohyperelasticity with transport and swelling (MPHETS) to derive a new method that models growth of biological soft tissues. The conservation equations and constitutive equations are developed for both solid-only growth and solid/fluid growth. An axisymmetric finite element framework is introduced for the new theory of growing MPHETS (GMPHETS). To illustrate the capabilities of this model, several example finite element test problems are considered using model geometry and material parameters based on experimental data from a porcine coronary artery. Multiple growth laws are considered, including time-driven, concentration-driven, and stress-driven growth. Time-driven growth is compared against an exact analytical solution to validate the model. For concentration-dependent growth, changing the diffusivity (representing a change in drug) fundamentally changes growth behavior. We further demonstrate that for stress-dependent, solid-only growth of an artery, growth of an MPHETS model results in a more uniform hoop stress than growth in a hyperelastic model for the same amount of growth time using the same growth law. This may have implications in the context of developing residual stresses in soft tissues under intraluminal pressure. To our knowledge, this manuscript provides the first full description of an MPHETS model with growth. The developed computational framework can be used in concert with novel in-vitro and in-vivo experimental approaches to identify the governing growth laws for various soft tissues.

  5. Selective thrombolysis performed through meningo-ophthalmic artery in central retinal artery occlusion.

    Science.gov (United States)

    Cohen, José E; Moscovici, Samuel; Halpert, Michael; Itshayek, Eyal

    2012-03-01

    The poor natural history of central retinal artery occlusion (CRAO) is usually not modified with conventional, conservative management techniques. Guidelines for selective intraarterial ophthalmic thrombolysis are still lacking. While many centers continue to perform this procedure with promising results, others are reluctant due to conflicting findings in recent studies. We present our experience in a 36-year-old male with CRAO. Based on the patient's clinical presentation, we planned to perform selective intraarterial ophthalmic thrombolysis via the ophthalmic artery. When angiography demonstrated that the retina was not supplied by the ophthalmic artery, but by a meningo-ophthalmic artery branching from the internal maxillary artery, we instead administered thrombolytic agents via the meningo-ophthalmic artery. The patient's vision recovered completely, with visual acuity and visual field examination at 30 day follow up comparable to his pre-treatment status. This case emphasizes the need for external carotid artery examination in cases of nonvisualization of the ophthalmic artery. In addition, it illustrates the successful use of the meningo-ophthalmic artery to perform selective intraarterial thrombolysis for CRAO.

  6. The new technique of using the epigastric arteries in renal transplantation with multiple renal arteries

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Amirzargar

    2013-01-01

    Full Text Available The most common anatomic variant seen in the donor kidneys for renal transplantation is multiple renal arteries (MRA, which can cause an increased risk of complications. We describe the long-term outcomes of 16 years of experience in 76 kidney transplantations with MRAs. In a new reconstruction technique, we remove arterial clamps after anastomosing the donor to the recipient′s main renal vessels, which cause backflow from accessory arteries to prevent thrombosis. By this technique, we reduce the ischemic times as well as the operating times. Both in live or cadaver donor kidneys, lower polar arteries were anastomosed to the inferior epigastric artery and upper polar arteries were anastomosed to the superior epigastric arteries. Injection of Papaverine and ablation of sympathic nerves of these arteries dilate and prevent them from post-operative spasm. Follow-up DTPA renal scan in all patients showed good perfusion and function of the transplanted kidney, except two cases of polar arterial thrombosis. Mean creatinine levels during at least two years of follow-up remained acceptable. Patient and graft survival were excellent. No cases of ATN, hypertension, rejection and urologic complications were found. In conclusion, this technique can be safely and successfully utilized for renal transplantation with kidneys having MRAs, and may be associated with a lower complication rate and better graft function compared with the existing techniques.

  7. Capsaicin and arterial hypertensive crisis.

    Science.gov (United States)

    Patanè, Salvatore; Marte, Filippo; La Rosa, Felice Carmelo; La Rocca, Roberto

    2010-10-08

    Chili peppers are rich in capsaicin. The potent vasodilator calcitonin gene-related peptide (CGRP) is stored in a population of C-fiber afferents that are sensitive to capsaicin. CGRP and peptides released from cardiac C fibers have a beneficial effect in myocardial ischemia and reperfusion. It has been reported that capsaicin pretreatment can deplete cardiac C-fiber peptide stores. Furthermore, it has also been reported that capsaicin-treated pigs have significantly increased mean arterial blood pressure compared with controls, and that the decrease in CGRP synthesis and release contributes to the elevated blood pressure. A case has also been reported of an arterial hypertensive crisis in a patient with a large ingestion of peppers and chili peppers the day before. We present a case of an arterial hypertensive crisis in a 19-year-old Italian man with an abundant ingestion of peppers and of chili peppers the preceding day. This case describes an unusual pattern of arterial hypertensive crisis due to capsaicin.

  8. Celiac Artery Compression Syndrome

    Directory of Open Access Journals (Sweden)

    Mohammed Muqeetadnan

    2013-01-01

    Full Text Available Celiac artery compression syndrome is a rare disorder characterized by episodic abdominal pain and weight loss. It is the result of external compression of celiac artery by the median arcuate ligament. We present a case of celiac artery compression syndrome in a 57-year-old male with severe postprandial abdominal pain and 30-pound weight loss. The patient eventually responded well to surgical division of the median arcuate ligament by laparoscopy.

  9. Popliteal artery entrapment syndrome.

    LENUS (Irish Health Repository)

    O'Leary, D P

    2010-01-01

    Popliteal artery entrapment syndrome is a rare abnormality of the anatomical relationship between the popliteal artery and adjacent muscles or fibrous bands in the popliteal fossa. The following is a case report of a 19 year old female, in whom popliteal artery entrapment syndrome was diagnosed, and successfully treated surgically. A review of literature is also presented and provides details on how PAES is classified, diagnosed both clinically and radiologically, and treated surgically.

  10. Bilateral Internal Thoracic Artery Configuration for Coronary Artery Bypass Surgery

    Science.gov (United States)

    Boodhwani, Munir; Hanet, Claude; de Kerchove, Laurent; Navarra, Emiliano; Astarci, Parla; Noirhomme, Philippe; El Khoury, Gebrine

    2016-01-01

    Background— Bilateral internal thoracic arteries (BITA) have demonstrated superior patency and improved survival in patients undergoing coronary artery bypass grafting. However, the optimal configuration for BITA utilization and its effect on long-term outcome remains uncertain. Methods and Results— We randomly assigned 304 patients undergoing coronary artery bypass grafting using BITA to either in situ or Y grafting configurations. The primary end point was 3-year angiographic patency. Secondary end points included major adverse cardiac and cerebrovascular events (ie, death from any cause, stroke, myocardial infarction, or repeat revascularization) at 7 years. More coronary targets were able to be revascularized using internal thoracic arteries in patients randomized to Y grafting versus in situ group (3.2±0.8 versus 2.4±0.5 arteries/patient; P<0.01). The primary end point did not show significant differences in graft patency between groups. Secondary end points occurred more frequently in the in situ group (P=0.03), with 7-year rates of 34±10% in the in situ and 25±12% in the Y grafting groups, driven largely by a higher incidence of repeat revascularization in the in situ group (14±4.5% versus 7.4±3.2% at 7 years; P=0.009). There were no significant differences in hospital mortality or morbidity or in late survival, myocardial infarction, or stroke between groups. Conclusions— Three-year systematic angiographic follow-up revealed no significant difference in graft patency between the 2 BITA configurations. However, compared with in situ configuration, the use of BITA in a Y grafting configuration results in lower rates of major adverse cardiovascular and cerebrovascular events at 7 years. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01666366. PMID:27406988

  11. Prevalence of type 2 diabetes is higher in peripheral artery disease than in coronary artery disease patients.

    Science.gov (United States)

    Silbernagel, Guenther; Rein, Philipp; Saely, Christoph H; Engelberger, Rolf P; Willenberg, Torsten; Do, Dai-Do; Kucher, Nils; Baumgartner, Iris; Drexel, Heinz

    2015-03-01

    Type 2 diabetes mellitus and pre-diabetes are risk factors for atherosclerosis and are highly prevalent in patients with coronary artery disease. However, the prevalence of impaired glucose metabolism in patients with peripheral artery disease is not as well elucidated. We aimed at comparing prevalence rates of type 2 diabetes mellitus and pre-diabetes, which were diagnosed according to the current American Diabetes Association criteria, among 364 patients with peripheral artery disease, 529 patients with coronary artery disease and 383 controls. The prevalence of type 2 diabetes mellitus in peripheral artery disease patients was 49.7%. It was significantly higher in these patients than in coronary artery disease patients (34.4%; p disease group with the coronary artery disease group (p disease group with controls (p prevalence of pre-diabetes among non-diabetic subjects was high in all three study groups (64.5% in peripheral artery disease patients, 63.4% in coronary artery disease patients and 61.8% in controls), without significant between-group differences. In conclusion, the prevalence of type 2 diabetes mellitus is even higher in peripheral artery disease patients than in coronary artery disease patients. This observation underlines the need to consider impaired glucose regulation in the management of peripheral artery disease.

  12. Arterial waveform analysis.

    Science.gov (United States)

    Esper, Stephen A; Pinsky, Michael R

    2014-12-01

    The bedside measurement of continuous arterial pressure values from waveform analysis has been routinely available via indwelling arterial catheterization for >50 years. Invasive blood pressure monitoring has been utilized in critically ill patients, in both the operating room and critical care units, to facilitate rapid diagnoses of cardiovascular insufficiency and monitor response to treatments aimed at correcting abnormalities before the consequences of either hypo- or hypertension are seen. Minimally invasive techniques to estimate cardiac output (CO) have gained increased appeal. This has led to the increased interest in arterial waveform analysis to provide this important information, as it is measured continuously in many operating rooms and intensive care units. Arterial waveform analysis also allows for the calculation of many so-called derived parameters intrinsically created by this pulse pressure profile. These include estimates of left ventricular stroke volume (SV), CO, vascular resistance, and during positive-pressure breathing, SV variation, and pulse pressure variation. This article focuses on the principles of arterial waveform analysis and their determinants, components of the arterial system, and arterial pulse contour. It will also address the advantage of measuring real-time CO by the arterial waveform and the benefits to measuring SV variation. Arterial waveform analysis has gained a large interest in the overall assessment and management of the critically ill and those at a risk of hemodynamic deterioration.

  13. The Relation of Finite Element and Finite Difference Methods

    Science.gov (United States)

    Vinokur, M.

    1976-01-01

    Finite element and finite difference methods are examined in order to bring out their relationship. It is shown that both methods use two types of discrete representations of continuous functions. They differ in that finite difference methods emphasize the discretization of independent variable, while finite element methods emphasize the discretization of dependent variable (referred to as functional approximations). An important point is that finite element methods use global piecewise functional approximations, while finite difference methods normally use local functional approximations. A general conclusion is that finite element methods are best designed to handle complex boundaries, while finite difference methods are superior for complex equations. It is also shown that finite volume difference methods possess many of the advantages attributed to finite element methods.

  14. Diagnostic performance of cardiac imaging methods to diagnose ischaemia-causing coronary artery disease when directly compared with fractional flow reserve as a reference standard: a meta-analysis

    Science.gov (United States)

    Danad, Ibrahim; Szymonifka, Jackie; Twisk, Jos W.R.; Norgaard, Bjarne L.; Zarins, Christopher K.; Knaapen, Paul

    2017-01-01

    Aims The aim of this study was to determine the diagnostic performance of single-photon emission computed tomography (SPECT), stress echocardiography (SE), invasive coronary angiography (ICA), coronary computed tomography angiography (CCTA), fractional flow reserve (FFR) derived from CCTA (FFRCT), and cardiac magnetic resonance (MRI) imaging when directly compared with an FFR reference standard. Method and results PubMed and Web of Knowledge were searched for investigations published between 1 January 2002 and 28 February 2015. Studies performing FFR in at least 75% of coronary vessels for the diagnosis of ischaemic coronary artery disease (CAD) were included. Twenty-three articles reporting on 3788 patients and 5323 vessels were identified. Meta-analysis was performed for pooled sensitivity, specificity, likelihood ratios (LR), diagnostic odds ratio, and summary receiver operating characteristic curves. In contrast to ICA, CCTA, and FFRCT reports, studies evaluating SPECT, SE, and MRI were largely retrospective, single-centre and with generally smaller study samples. On a per-patient basis, the sensitivity of CCTA (90%, 95% CI: 86–93), FFRCT (90%, 95% CI: 85–93), and MRI (90%, 95% CI: 75–97) were higher than for SPECT (70%, 95% CI: 59–80), SE (77%, 95% CI: 61–88), and ICA (69%, 95% CI: 65–75). The highest and lowest per-patient specificity was observed for MRI (94%, 95% CI: 79–99) and for CCTA (39%, 95% CI: 34–44), respectively. Similar specificities were noted for SPECT (78%, 95% CI: 68–87), SE (75%, 95% CI: 63–85), FFRCT (71%, 95% CI: 65–75%), and ICA (67%, 95% CI: 63–71). On a per-vessel basis, the highest sensitivity was for CCTA (pooled sensitivity, 91%: 88–93), MRI (91%: 84–95), and FFRCT (83%, 78–87), with lower sensitivities for ICA (71%, 69–74), and SPECT (57%: 49–64). Per-vessel specificity was highest for MRI (85%, 79–89), FFRCT (78%: 78–81), and SPECT (75%: 69–80), whereas ICA (66%: 64–68) and CCTA (58%: 55

  15. Gravity-induced stresses in finite slopes

    Science.gov (United States)

    Savage, W.Z.

    1994-01-01

    An exact solution for gravity-induced stresses in finite elastic slopes is presented. This solution, which is applied for gravity-induced stresses in 15, 30, 45 and 90?? finite slopes, has application in pit-slope design, compares favorably with published finite element results for this problem and satisfies the conditions that shear and normal stresses vanish on the ground surface. The solution predicts that horizontal stresses are compressive along the top of the slopes (zero in the case of the 90?? slope) and tensile away from the bottom of the slopes, effects which are caused by downward movement and near-surface horizontal extension in front of the slope in response to gravity loading caused by the additional material associated with the finite slope. ?? 1994.

  16. Anomalous origin of right coronary artery from pulmonary artery

    Directory of Open Access Journals (Sweden)

    Rajat Gupta

    2012-01-01

    Full Text Available Anomalous origin of coronary artery from the pulmonary artery is a rare anomaly that most frequently involves the left coronary artery and very rarely the right coronary artery. These lesions can be missed on echocardiography unless carefully looked for. We describe a case of isolated anomalous origin of right coronary artery from pulmonary artery diagnosed on echocardiography and confirmed by computed tomography (CT angiography.

  17. Estudo comparativo de diferentes prescrições de braquetes pré-ajustados em modelos virtuais pelo Método de Elementos Finitos Comparative study of different pre-adjusted brackets prescriptions on virtual models, by Finite Elements Method

    Directory of Open Access Journals (Sweden)

    Murilo Fernando Neuppmann Feres

    2009-08-01

    Full Text Available OBJETIVOS: comparar os efeitos de diferentes prescrições de braquetes pré-ajustados na movimentação dentária dos dentes anterossuperiores, por meio da utilização do Método de Elementos Finitos (MEF. MÉTODOS: foi utilizado um modelo tridimensional composto por um incisivo central, um incisivo lateral e um canino, todos do hemiarco superior esquerdo. Esses elementos foram submetidos à atuação de vetores de força que simularam a ação dos pré-ajustes de angulação e torque dos braquetes das prescrições de Alexander, Andrews, Capelozza, MBT, Ricketts e Roth. Após a simulação, os dados referentes ao deslocamento espacial dos pontos incisais e apicais foram registrados de forma que o novo posicionamento admitido pelos longos eixos dentários e seus pontos constituintes fossem determinados. RESULTADOS: a maioria das prescrições se comportou similarmente em relação aos parâmetros avaliados. As diferenças significativas encontradas no estudo se referem ao incisivo lateral superior que continha o braquete com a prescrição de Ricketts, que apresentou uma menor inclinação vestibular de seu longo eixo. Além disso, o canino superior da mesma prescrição apresentou uma maior inclinação de seu longo eixo para mesial e uma maior inclinação vestibular de seu longo eixo em relação às outras. A avaliação qualitativa da movimentação do incisivo central superior indicou um maior deslocamento distal dos ápices radiculares para as prescrições cujos autores estipularam maiores valores de angulação (Andrews, Capelozza, Roth e Alexander, e um maior deslocamento vestibular da coroa para as prescrições que estipularam os maiores valores de torque para os incisivos centrais (Ricketts, MBT, Alexander e Roth.AIM: The aim of the present study was to compare the effects of different prescriptions on anterior superior tooth movement simulation through a Finite Element Method (FEM. METHODS: It was utilized a 3D model, which was

  18. Normal hips and the hips covered with protective brace A finite-element comparative analysis%正常髋部与佩戴保护支具髋部的有限元对比分析

    Institute of Scientific and Technical Information of China (English)

    何剑颖; 董谢平

    2011-01-01

    BACKGROUND: Finite element method has become an important means for biomechanical study against sideways falls because of its unlimited sample size, small experimental error and good repeatability.OBJECTIVE: To establish three-dimensional normal pelvis and brace-covered pelvis models and then to analyze the stress, strain and displacement distribution during sideways fall and to verify the effectiveness of hip brace.METHODS: Digital human Abaqus 6.51 software was used to build three-dimensional normal pelvis and brace-covered pelvis models. The rigid constraint surface was fixed. The whole pelvic model was loaded with 2 m/s loading. The stress, strain and displacement variation with time and contours were detected prior to and after wearing the hip brace. RESULTS AND CONCLUSION: Compared with the normal model, the contact force between the pelvis and the ground, the maximal compression strain of the cancellous bone when the maximal contact force between the pelvis and the ground generated, the maximal strain of the greater trochanter and femoral neck, the maximal von-Mises stress of the greater trochanter and femoral neck, and the mean stress of the greater trochanter and femoral neck were significantly reduced in the brace-covered pelvis model during sideways falls. These findings indicate that the hip brace can play a protective role in the greater trochanter, and effectively reduce the incidence of intertrochanteric fractures during sideways fall.%背景:有限元法因其具有不受样本量限制,实验误差小,重复性好等优点而成为防滑倒生物力学研究的重要手段.目的:建立正常骨盆以及佩戴护具骨盆的三维有限元模型,分析滑倒过程中骨盆各部位的应力、应变和位移分布,验证护具的有效性.方法:以中国数字人原始资料应用Abaqus 6.51软件构建正常骨盆以及佩戴护具骨盆的三维有限元模型,固定约束地面刚体,对整个骨盆模型加载2 m/s的速度载荷,程序运算

  19. Coronary artery bypass graft (CABG) surgery patients in a clinical pathway gained less in health-related quality of life as compared with patients who undergo CABG in a conventional-care plan

    NARCIS (Netherlands)

    El Baz, Noha; Middel, Berrie; van Dijk, Jitse P.; Boonstra, Piet W.; Reijneveld, Sijmen A.

    2009-01-01

    The aim of this study is to determine the difference between clinical pathway (CP) and conventional care in terms of health-related quality of life (HRQoL) domains, depression and anxiety, as well as to determine the relative contribution of CP towards an improved HRQoL after coronary artery bypass

  20. Carotid artery stenting will replace carotid endarterectomy.

    Science.gov (United States)

    McCormick, Daniel J; Vlad, Tudor; Fasseas, Panayotis

    2007-09-01

    Stroke is the third leading cause of death in the United States. Carotid artery stenosis represents one of the most common etiologies of stroke. The current treatment modalities available for the treatment of carotid artery stenosis are carotid endarterectomy (CEA) and carotid artery stenting (CAS). Several clinical trials comparing CEA with medical management showed superiority of the surgical arm; however, the applicability of these results to the general population is limited by the fact that the patients and surgeons enrolled in these trials were carefully selected, and the optimal medical therapy used does not meet the current treatment standards. Carotid artery stenting has emerged as a treatment alternative to CEA, as shown in randomized trials comparing the 2 treatment modalities. Recent data from large-volume CAS registries indicate that percutaneous treatment of carotid artery stenosis compares favorably to CEA. Furthermore, the CAS trial designs make these results more applicable to the community standards. These data suggest that CAS will become the treatment of choice in patients with carotid artery stenosis.

  1. Mathematical modelling of triple arterial stenoses.

    Science.gov (United States)

    Ang, K C; Mazumdar, J

    1995-06-01

    This paper examines the effects of triple stenoses (ie. three stenoses in series) in a reasonably large artery. The model developed is axi-symmetric and blood is assumed to be a Newtonian fluid. The governing equations are the Navier-Stokes equations and the continuity equation. These equations are solved using the Finite Element Method and the FIDAP computational fluid dynamics (C.F.D.) package. Various combinations of differing degrees of stenosis in the triplet are considered. Pressure drop profiles and streamline plots of the solutions to these models show that the effects of milder stenoses are diminished in the presence of more severe ones. Also, a pressure recovery is observed whenever a mild stenosis follows a more severe stenosis in multiply stenosed arteries.

  2. Assessment Of Coronary Artery Aneurysms Using Transluminal Attenuation Gradient And Computational Modeling In Kawasaki Disease Patients

    Science.gov (United States)

    Grande Gutierrez, Noelia; Kahn, Andrew; Shirinsky, Olga; Gagarina, Nina; Lyskina, Galina; Fukazawa, Ryuji; Owaga, Shunichi; Burns, Jane; Marsden, Alison

    2015-11-01

    Kawasaki Disease (KD) can result in coronary artery aneurysms (CAA) in up to 25% of patients, putting them at risk of thrombus formation, myocardial infarction and sudden death. Clinical guidelines recommend CAA diameter >8 mm as the arbitrary criterion for initiating systemic anticoagulation. KD patient specific modeling and flow simulations suggest that hemodynamic data can predict regions at increased risk of thrombosis. Transluminal Attenuation Gradient (TAG) is determined from the change in radiological attenuation per vessel length and has been proposed as a non-invasive method for characterizing coronary stenosis from CT Angiography. We hypothesized that CAA abnormal flow could be quantified using TAG. We computed hemodynamics for patient specific coronary models using a stabilized finite element method, coupled numerically to a lumped parameter network to model the heart and vascular boundary conditions. TAG was quantified in the major coronary arteries. We compared TAG for aneurysmal and normal arteries and we analyzed TAG correlation with hemodynamic and geometrical parameters. Our results suggest that TAG may provide hemodynamic data not available from anatomy alone. TAG represents a possible extension to standard CTA that could help to better evaluate the risk of thrombus formation in KD.

  3. Feeding Arteries of Primary Tongue Cancers on Intra-arterial Infusion Chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kamitani, Takeshi, E-mail: kamitani@radiol.med.kyushu-u.ac.jp [Kyushu University, Department of Clinical Radiology, Graduate School of Medical Sciences (Japan); Kawanami, Satoshi, E-mail: kawanami-01@mac.com [Kyushu University, Department of Molecular Imaging and Diagnosis, Graduate School of Medical Sciences (Japan); Asayama, Yoshiki, E-mail: asayama@radiol.med.kyushu-u.ac.jp; Matsuo, Yoshio, E-mail: yymatsuo@radiol.med.kyushu-u.ac.jp; Yonezawa, Masato, E-mail: ymasato@radiol.med.kyushu-u.ac.jp; Yamasaki, Yuzo, E-mail: yyama@radiol.med.kyushu-u.ac.jp [Kyushu University, Department of Clinical Radiology, Graduate School of Medical Sciences (Japan); Nagao, Michinobu, E-mail: minagao@radiol.med.kyushu-u.ac.jp [Kyushu University, Department of Molecular Imaging and Diagnosis, Graduate School of Medical Sciences (Japan); Yamanouchi, Torahiko, E-mail: tora0228@radiol.med.kyushu-u.ac.jp [Kyushu University, Department of Clinical Radiology, Graduate School of Medical Sciences (Japan); Yabuuchi, Hidetake, E-mail: h-yabu@med.kyushu-u.ac.jp [Kyushu University, Department of Health Sciences, Graduate School of Medical Sciences (Japan); Nakamura, Katsumasa, E-mail: nakam@radiol.med.kyushu-u.ac.jp [Kyushu University, Department of Clinical Radiology, Graduate School of Medical Sciences (Japan); Nakashima, Torahiko, E-mail: nakatora@qent.med.kyushu-u.ac.jp [Kyushu University, Department of Otorhinolaryngology, Graduate School of Medical Sciences (Japan); Honda, Hiroshi, E-mail: honda@radiol.med.kyushu-u.ac.jp [Kyushu University, Department of Clinical Radiology, Graduate School of Medical Sciences (Japan)

    2016-02-15

    PurposeTo evaluate the frequency and the predictive factor of each feeding artery on intra-arterial infusion chemotherapy (IAIC) in primary tongue cancer.Materials and MethodsWe retrospectively evaluated 20 patients who received IAIC for primary tongue cancer. The main and accompanying feeding arteries were identified on super-selective angiography of the branches of the external carotid artery. Tumor diameter, and extension to the contralateral side, tongue extrinsic muscles (TEMs), and lateral mesopharyngeal wall were determined based on magnetic resonance imaging or computed tomography findings.ResultsThe main feeding artery was the ipsilateral lingual artery (LA) in 15 of the 20 examined tumors and the contralateral LA in the other 5. Ten cancers had only one feeding artery, and multiple feeding arteries were detected in the remaining 10. Tumors >4 cm (n = 9), those with extension to the contralateral side (n = 13), and those with extension to TEMs (n = 15) were supplied by significantly larger numbers of feeding arteries compared to tumors without these features (P = 0.01, 0.049, and 0.02, respectively). The frequency of feeding from the contralateral LA was 64 % (9/14) and 17 % (1/6) in tumors with and without extension to the contralateral side, respectively. Feeding from a facial artery (FA) was not detected in tumors ≤4 cm, while 5 of the 9 (56 %) tumors >4 cm were supplied by a FA (P = 0.01).ConclusionA careful search for feeding arteries is required, especially in large tumors with extension to the contralateral side or to TEMs.

  4. Finite Discrete Gabor Analysis

    DEFF Research Database (Denmark)

    Søndergaard, Peter Lempel

    2007-01-01

    can also be related by sampling and periodization. This thesis extends on this theory by showing new results for window construction. It also provides a discussion of the problems associated to discrete Gabor bases. The sampling and periodization connection is handy because it allows Gabor systems...... on the real line to be well approximated by finite and discrete Gabor frames. This method of approximation is especially attractive because efficient numerical methods exists for doing computations with finite, discrete Gabor systems. This thesis presents new algorithms for the efficient computation of finite......, discrete Gabor coefficients. Reconstruction of a signal from its Gabor coefficients is done by the use of a so-called dual window. This thesis presents a number of iterative algorithms to compute dual and self-dual windows. The Linear Time Frequency Toolbox is a Matlab/Octave/C toolbox for doing basic...

  5. A comparative study on plaque vulnerability using constitutive equations.

    Science.gov (United States)

    Karimi, A; Navidbakhsh, M; Faghihi, S

    2014-03-01

    Atherosclerosis is the most serious and common form of cardiovascular disease in which plaque builds up inside the arteries. Peak plaque stress is considered as the main reason for plaque rupture, which results in heart attack and stroke. In the current research, the finite element method is used to anticipate plaque vulnerability, using human samples. A total of 23 healthy and atherosclerotic human coronary arteries (14 healthy and 9 atherosclerotic) were removed within 5 h postmortem. The samples were mounted on a uniaxial tensile test machine and the obtained mechanical properties were used in finite element models. The peak plaque stresses for the Ogden hyperelastic model were compared to the Mooney-Rivlin and Neo-Hookean outcomes. The results indicated that hypocellular plaque in all three models has the highest stress values compared to the cellular and calcified ones and, as a result, is quite prone to rupture. The calcified plaque type, in contrast, has the lowest stress values and remains stable. The results can be used in plaque vulnerability prediction and have clinical implications for interventions and surgeries such as balloon-angioplasty, cardiopulmonary bypass and stenting.

  6. Adaptive finite difference for seismic wavefield modelling in acoustic media.

    Science.gov (United States)

    Yao, Gang; Wu, Di; Debens, Henry Alexander

    2016-08-05

    Efficient numerical seismic wavefield modelling is a key component of modern seismic imaging techniques, such as reverse-time migration and full-waveform inversion. Finite difference methods are perhaps the most widely used numerical approach for forward modelling, and here we introduce a novel scheme for implementing finite difference by introducing a time-to-space wavelet mapping. Finite difference coefficients are then computed by minimising the difference between the spatial derivatives of the mapped wavelet and the finite difference operator over all propagation angles. Since the coefficients vary adaptively with different velocities and source wavelet bandwidths, the method is capable to maximise the accuracy of the finite difference operator. Numerical examples demonstrate that this method is superior to standard finite difference methods, while comparable to Zhang's optimised finite difference scheme.

  7. A multigrid solution method for mixed hybrid finite elements

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, W. [Universitaet Augsburg (Germany)

    1996-12-31

    We consider the multigrid solution of linear equations arising within the discretization of elliptic second order boundary value problems of the form by mixed hybrid finite elements. Using the equivalence of mixed hybrid finite elements and non-conforming nodal finite elements, we construct a multigrid scheme for the corresponding non-conforming finite elements, and, by this equivalence, for the mixed hybrid finite elements, following guidelines from Arbogast/Chen. For a rectangular triangulation of the computational domain, this non-conforming schemes are the so-called nodal finite elements. We explicitly construct prolongation and restriction operators for this type of non-conforming finite elements. We discuss the use of plain multigrid and the multilevel-preconditioned cg-method and compare their efficiency in numerical tests.

  8. Arterial hypoxaemia in cirrhosis

    DEFF Research Database (Denmark)

    Møller, S; Hillingsø, Jens; Christensen, E

    1998-01-01

    BACKGROUND: Although low arterial oxygen tension (Po2) has been claimed to occur in one to two thirds of patients with cirrhosis, hypoxaemia appears to be rare in clinical practice. AIMS: To assess the frequency of arterial hypoxaemia in cirrhosis in relation to clinical and haemodynamic......%, 96%, 96%, and 93% (NS). So2 was below the lower limit of 92% in 0%, 9%, 7%, and 24% (p arterial carbon dioxide tension, a low systemic vascular...... resistance, and a low indocyanine green clearance (p arterial hypoxaemia in cirrhosis is about 22% in patients without encephalopathy, but it varies from 10-40% depending on the degree of hepatic dysfunction. Arterial hypoxaemia in patients with cirrhosis of differing...

  9. Artery by Neuropeptides

    Directory of Open Access Journals (Sweden)

    Esmeralda Sofia Costa Delgado

    2012-01-01

    Methods. Isolated rabbit eyes (n=12 were perfused in situ with tyrode through the external ophthalmic artery. Effects of intra-arterial injections of NPY 200 μg/ml (Group A; n=6 and VIP 200 μg/ml (Group B; n=6 on the recorded pressure were obtained. For statistical analysis, Student's paired t-test and Fast Fourier Transform were used. Results. Spontaneous oscillations were observed before any drug administration in the 12 rabbit models. NPY produced an increase in total vascular resistance and a higher frequency and amplitude of oscillations, while VIP evoked the opposite effects. Conclusions. This study provides evidence of vasomotion in basal conditions in rabbit external ophthalmic artery. Concerning drug effects, NPY increased arterial resistance and enhanced vasomotion while VIP produced opposite effects which demonstrates their profound influence in arterial vasomotion.

  10. [Transposition of Great Artery].

    Science.gov (United States)

    Konuma, Takeshi; Shimpo, Hideto

    2015-07-01

    Transposition of the great artery is one of common congenital cardiac disease resulting cyanosis. Death occurs easily in untreated patients with transposition and intact ventricular septal defect (VSD) in infancy at a few days of age when posterior descending coronary artery (PDA) closed. Since there are 2 parallel circulations, flow from pulmonary to systemic circulation is necessary for systemic oxygenation, and Balloon atrial septostomy or prostaglandin infusion should be performed especially if patient do not have VSD. Although the advent of fetal echocardiography, it is difficult to diagnose the transposition of the great arteries (TGA) as abnormality of great vessels is relatively undistinguishable. The diagnosis of transposition is in itself an indication for surgery, and arterial switch procedure is performed in the case the left ventricle pressure remains more than 2/3 of systemic pressure. Preoperative diagnosis is important as associated anomalies and coronary artery branching patterns are important to decide the operative indication and timing of surgery.

  11. Finite element analysis

    CERN Document Server

    2010-01-01

    Finite element analysis is an engineering method for the numerical analysis of complex structures. This book provides a bird's eye view on this very broad matter through 27 original and innovative research studies exhibiting various investigation directions. Through its chapters the reader will have access to works related to Biomedical Engineering, Materials Engineering, Process Analysis and Civil Engineering. The text is addressed not only to researchers, but also to professional engineers, engineering lecturers and students seeking to gain a better understanding of where Finite Element Analysis stands today.

  12. Finite element mesh generation

    CERN Document Server

    Lo, Daniel SH

    2014-01-01

    Highlights the Progression of Meshing Technologies and Their ApplicationsFinite Element Mesh Generation provides a concise and comprehensive guide to the application of finite element mesh generation over 2D domains, curved surfaces, and 3D space. Organised according to the geometry and dimension of the problem domains, it develops from the basic meshing algorithms to the most advanced schemes to deal with problems with specific requirements such as boundary conformity, adaptive and anisotropic elements, shape qualities, and mesh optimization. It sets out the fundamentals of popular techniques

  13. The finite Bruck Loops

    CERN Document Server

    Baumeister, Barbara

    2009-01-01

    We continue the work by Aschbacher, Kinyon and Phillips [AKP] as well as of Glauberman [Glaub1,2] by describing the structure of the finite Bruck loops. We show essentially that a finite Bruck loop $X$ is the direct product of a Bruck loop of odd order with either a soluble Bruck loop of 2-power order or a product of loops related to the groups $PSL_2(q)$, $q= 9$ or $q \\geq 5$ a Fermat prime. The latter possibillity does occur as is shown in [Nag1, BS]. As corollaries we obtain versions of Sylow's, Lagrange's and Hall's Theorems for loops.

  14. Skin autofluorescence is increased in patients with carotid artery stenosis and peripheral artery disease.

    Science.gov (United States)

    Noordzij, Marjon J; Lefrandt, Joop D; Loeffen, Erik A H; Saleem, Ben R; Meerwaldt, Robbert; Lutgers, Helen L; Smit, Andries J; Zeebregts, Clark J

    2012-02-01

    Advanced glycation end products (AGEs) have a pivotal role in atherosclerosis. We evaluated skin autofluorescence (SAF), a non-invasive measurement of tissue AGE accumulation, in patients with carotid artery stenosis with and without coexisting peripheral artery occlusive disease (PAOD). SAF was measured using the AGE Reader™ in 56 patients with carotid artery stenosis and in 56 age- and sex-matched healthy controls without diabetes, renal dysfunction or known atherosclerotic disease. SAF was higher in patients with carotid artery stenosis compared to the control group: mean 2.81 versus 2.46 (P = 0.002), but especially in the younger age group of 50-60 years old: mean 2.82 versus 1.94 (P = 0.000). Patients with carotid artery stenosis and PAOD proved to have an even higher SAF than patients with carotid artery stenosis only: mean 3.28 versus 2.66 (P = 0.003). Backward linear regression analysis showed that age, smoking, diabetes mellitus, renal function and the presence of PAOD were the determinants of SAF, but carotid artery stenosis was not. SAF is increased in patients with carotid artery stenosis and PAOD. The univariate and multivariate associations of SAF with age, smoking, diabetes, renal insufficiency and PAOD suggest that increased SAF can be seen as an indicator of widespread atherosclerosis.

  15. Comparative Efficacy and Safety of Different Antiplatelet Agents for Prevention of Major Cardiovascular Events and Leg Amputations in Patients with Peripheral Arterial Disease: A Systematic Review and Network Meta-Analysis

    Science.gov (United States)

    Katsanos, Konstantinos; Spiliopoulos, Stavros; Saha, Prakash; Diamantopoulos, Athanasios; Karunanithy, Narayan; Krokidis, Miltiadis; Modarai, Bijan; Karnabatidis, Dimitris

    2015-01-01

    There is a lack of consensus regarding which type of antiplatelet agent should be used in patients with peripheral arterial disease (PAD) and little is known on the advantages and disadvantages of dual antiplatelet therapy. We conducted a systematic review and network meta-analysis of available randomized controlled trials (RCT) comparing different antiplatelet drugs (Aspirin, Ticlopidine, Clopidogrel, Ticagrelor, Cilostazol, Picotamide and Vorapaxar as monotherapies or in combination with aspirin) in PAD patients (PROSPERO public database; CRD42014010299).We collated evidence from previous relevant meta-analyses and searched online databases. Primary efficacy endpoints were: (1) the composite rate of major adverse cardiovascular events (MACE; including vascular deaths, non-fatal myocardial infarction and non-fatal stroke), and (2) the rate of major leg amputations. The primary safety endpoint was the rate of severe bleeding events. Bayesian models were employed for multiple treatment comparisons and risk-stratified hierarchies of comparative efficacy were produced to aid medical decision making. Number-Needed-to-Treat (NNT) and Number-Needed-to-Harm (NNH) are reported in case of significant results. We analyzed 49 RCTs comprising 34,518 patients with 88,358 person-years of follow-up with placebo as reference treatment. Aspirin, Cilostazol, Vorapaxar and Picotamide were ineffective in reducing MACE. A significant MACE reduction was noted with Ticagrelor plus aspirin (RR: 0.67; 95%CrI: 0.46–0.96, NNT = 66), Clopidogrel (RR: 0.72; 95%CrI: 0.58–0.91, NNT = 80), Ticlopidine (RR: 0.75; 95%CrI: 0.58–0.96, NNT = 87), and Clopidogrel plus aspirin (RR: 0.78; 95%CrI: 0.61–0.99, NNT = 98). Dual antiplatelet therapy with Clopidogrel plus aspirin significantly reduced major amputations following leg revascularization (RR: 0.68; 95%CrI: 0.46–0.99 compared to aspirin, NNT = 94). The risk of severe bleeding was significantly higher with Ticlopidine (RR: 5.03; 95%CrI: 1

  16. Simulation of stent deployment in a realistic human coronary artery

    Directory of Open Access Journals (Sweden)

    van der Steen Anton FW

    2008-08-01

    Full Text Available Abstract Background The process of restenosis after a stenting procedure is related to local biomechanical environment. Arterial wall stresses caused by the interaction of the stent with the vascular wall and possibly stress induced stent strut fracture are two important parameters. The knowledge of these parameters after stent deployment in a patient derived 3D reconstruction of a diseased coronary artery might give insights in the understanding of the process of restenosis. Methods 3D reconstruction of a mildly stenosed coronary artery was carried out based on a combination of biplane angiography and intravascular ultrasound. Finite element method computations were performed to simulate the deployment of a stent inside the reconstructed coronary artery model at inflation pressure of 1.0 MPa. Strut thickness of the stent was varied to investigate stresses in the stent and the vessel wall. Results Deformed configurations, pressure-lumen area relationship and stress distribution in the arterial wall and stent struts were studied. The simulations show how the stent pushes the arterial wall towards the outside allowing the expansion of the occluded artery. Higher stresses in the arterial wall are present behind the stent struts and in regions where the arterial wall was thin. Values of 200 MPa for the peak stresses in the stent strut were detected near the connecting parts between the stent struts, and they were only just below the fatigue stress. Decreasing strut thickness might reduce arterial damage without increasing stresses in the struts significantly. Conclusion The method presented in this paper can be used to predict stresses in the stent struts and the vessel wall, and thus evaluate whether a specific stent design is optimal for a specific patient.

  17. A Meta-analysis of transcatheter arterial chemoembolization comparing stereotactic body radiation the-rapy in patients for primary hepatic carcinoma%TACE联合SBRT治疗原发性肝癌的Meta分析

    Institute of Scientific and Technical Information of China (English)

    陈亚平; 姜晓晓; 蒋冠; 冯守信

    2015-01-01

    目的:系统评价经导管肝动脉化疗栓塞术( TACE )单用与联合应用体部立体定向放疗( SBRT)治疗原发性肝癌的疗效和不良反应,为临床实践提供参考。方法检索PubMed、Cochrane Library、EMBase、Ovid、MEDLINE、中国期刊全文数据库、中国生物医学文献数据库、中文科技期刊全文数据库、医学期刊全文数据库,查找关于TACE和SBRT治疗原发性肝癌的临床对照试验研究。按照Cochrane协作网的RevMan 5.2软件进行Meta分析。分析TACE单用与联合应用SBRT两组间的近期疗效,肿瘤局部控制率,1、2、3、5年生存率的差异。结果共有10篇文献,1143例患者满足纳入标准。Meta分析结果显示, TACE联合SBRT组比单纯TACE组近期疗效,肿瘤局部控制率,1、2、3、5生存率均高(RR=1.43,95%CI为1.32~1.56,P﹤0.00001;RR=2.09,95%CI为1.63~2.69,P﹤0.00001;RR=1.31,95%CI 为1.21~1.42,P﹤0.00001;RR=1.46,95%CI为1.23~1.72,P﹤0.00001;RR=1.76,95%CI为1.14~2.71,P=0.01;RR=2.29,95%CI为1.22~4.32,P=0.01)。白细胞减少( RR=0.97,P=0.61)、血小板减少( RR=0.99,P=0.85)、血红蛋白减少(RR=0.95,P=0.63)、恶心呕吐(RR=1.00,P=0.98)、肝功能损害(RR=0.98,P=0.87)的发生率两组之间差异无统计学意义。结论与TACE相比,TACE联合SBRT能明显提高患者近期疗效,提高肿瘤局部控制率和1、2、3、5生存率,同时不增加不良反应发生率,但其长期疗效和安全性尚需开展更多大样本、高质量的临床对照试验加以验证。%Objective To compare the clinical efficacy and the adverse reaction of transcatheter arteri-al chemoembolization( TACE)alone and combined with stereotactic body radiation therapy( SBRT)in patients with primary hepatic carcinoma by a Meta-analysis. Methods PubMed,Cochrane Library,EMBase,Ovid, MEDLIN,CNKI,CBMdisc,VIP and Wanfang were

  18. Finite Complements in English

    Institute of Scientific and Technical Information of China (English)

    Ronald W. Langacker

    2008-01-01

    This paper explores the conceptual basis of finite complimentation in English.It first considem the distinguishing property of a finite clause,namely grounding,effeeted by tense and the modals.Notions crucial for clausal grounding--including a reality conception and the striving for control at the effective and epistemic levelsalso figure in the semantic import of eomplementation.An essential feature of complement constructions is the involvement of multiple conceptualizers,each with their own conception of reality.The different types of complement and their grammatical markings can be characterized on this basis.Finite complements differ from other types by virtue of expressing an autonomous proposition capable of being apprehended by multiple conceptualizers,each from their own vantage point.Acognitive model representing phases in the striving for epistemic control provides a partial basis for the semantic description of predicates taking finite complements.The same model supports the description of both personal and impersonal complement constructions.

  19. Finite unified models

    Energy Technology Data Exchange (ETDEWEB)

    Kapetanakis, D. (Technische Univ. Muenchen, Garching (Germany). Physik Dept.); Mondragon, M. (Technische Univ. Muenchen, Garching (Germany). Physik Dept.); Zoupanos, G. (National Technical Univ., Athens (Greece). Physics Dept.)

    1993-09-01

    We present phenomenologically viable SU(5) unified models which are finite to all orders before the spontaneous symmetry breaking. In the case of two models with three families the top quark mass is predicted to be 178.8 GeV. (orig.)

  20. Gluons at finite temperature

    CERN Document Server

    Silva, P J; Dudal, D; Bicudo, P; Cardoso, N

    2016-01-01

    The gluon propagator is investigated at finite temperature via lattice simulations. In particular, we discuss its interpretation as a massive-type bosonic propagator. Moreover, we compute the corresponding spectral density and study the violation of spectral positivity. Finally, we explore the dependence of the gluon propagator on the phase of the Polyakov loop.

  1. Finite q-oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Atakishiyev, Natig M [Centro de Ciencias FIsicas, UNAM, Apartado Postal 48-3, 62251 Cuernavaca, Morelos (Mexico); Klimyk, Anatoliy U [Centro de Ciencias FIsicas, UNAM, Apartado Postal 48-3, 62251 Cuernavaca, Morelos (Mexico); Wolf, Kurt Bernardo [Centro de Ciencias FIsicas, UNAM, Apartado Postal 48-3, 62251 Cuernavaca, Morelos (Mexico)

    2004-05-28

    The finite q-oscillator is a model that obeys the dynamics of the harmonic oscillator, with the operators of position, momentum and Hamiltonian being functions of elements of the q-algebra su{sub q}(2). The spectrum of position in this discrete system, in a fixed representation j, consists of 2j + 1 'sensor'-points x{sub s} = 1/2 [2s]{sub q}, s element of {l_brace}-j, -j+1, ..., j{r_brace}, and similarly for the momentum observable. The spectrum of energies is finite and equally spaced, so the system supports coherent states. The wavefunctions involve dual q-Kravchuk polynomials, which are solutions to a finite-difference Schroedinger equation. Time evolution (times a phase) defines the fractional Fourier-q-Kravchuk transform. In the classical limit as q {yields} 1 we recover the finite oscillator Lie algebra, the N = 2j {yields} {infinity} limit returns the Macfarlane-Biedenharn q-oscillator and both limits contract the generators to the standard quantum-mechanical harmonic oscillator.

  2. Finite q-oscillator

    Science.gov (United States)

    Atakishiyev, Natig M.; Klimyk, Anatoliy U.; Wolf, Kurt Bernardo

    2004-05-01

    The finite q-oscillator is a model that obeys the dynamics of the harmonic oscillator, with the operators of position, momentum and Hamiltonian being functions of elements of the q-algebra suq(2). The spectrum of position in this discrete system, in a fixed representation j, consists of 2j + 1 'sensor'-points x_s={\\case12}[2s]_q, s\\in\\{-j,-j+1,\\ldots,j\\} , and similarly for the momentum observable. The spectrum of energies is finite and equally spaced, so the system supports coherent states. The wavefunctions involve dual q-Kravchuk polynomials, which are solutions to a finite-difference Schrödinger equation. Time evolution (times a phase) defines the fractional Fourier-q-Kravchuk transform. In the classical limit as q rarr 1 we recover the finite oscillator Lie algebra, the N = 2j rarr infin limit returns the Macfarlane-Biedenharn q-oscillator and both limits contract the generators to the standard quantum-mechanical harmonic oscillator.

  3. Algorithms for finite rings

    NARCIS (Netherlands)

    Ciocanea Teodorescu I.,

    2016-01-01

    In this thesis we are interested in describing algorithms that answer questions arising in ring and module theory. Our focus is on deterministic polynomial-time algorithms and rings and modules that are finite. The first main result of this thesis is a solution to the module isomorphism problem in

  4. Inside finite elements

    CERN Document Server

    Weiser, Martin

    2016-01-01

    All relevant implementation aspects of finite element methods are discussed in this book. The focus is on algorithms and data structures as well as on their concrete implementation. Theory is covered as far as it gives insight into the construction of algorithms. Throughout the exercises a complete FE-solver for scalar 2D problems will be implemented in Matlab/Octave.

  5. Hemodynamic analysis in an idealized artery tree: differences in wall shear stress between Newtonian and non-Newtonian blood models.

    Directory of Open Access Journals (Sweden)

    Jared C Weddell

    Full Text Available Development of many conditions and disorders, such as atherosclerosis and stroke, are dependent upon hemodynamic forces. To accurately predict and prevent these conditions and disorders hemodynamic forces must be properly mapped. Here we compare a shear-rate dependent fluid (SDF constitutive model, based on the works by Yasuda et al in 1981, against a Newtonian model of blood. We verify our stabilized finite element numerical method with the benchmark lid-driven cavity flow problem. Numerical simulations show that the Newtonian model gives similar velocity profiles in the 2-dimensional cavity given different height and width dimensions, given the same Reynolds number. Conversely, the SDF model gave dissimilar velocity profiles, differing from the Newtonian velocity profiles by up to 25% in velocity magnitudes. This difference can affect estimation in platelet distribution within blood vessels or magnetic nanoparticle delivery. Wall shear stress (WSS is an important quantity involved in vascular remodeling through integrin and adhesion molecule mechanotransduction. The SDF model gave a 7.3-fold greater WSS than the Newtonian model at the top of the 3-dimensional cavity. The SDF model gave a 37.7-fold greater WSS than the Newtonian model at artery walls located immediately after bifurcations in the idealized femoral artery tree. The pressure drop across arteries reveals arterial sections highly resistive to flow which correlates with stenosis formation. Numerical simulations give the pressure drop across the idealized femoral artery tree with the SDF model which is approximately 2.3-fold higher than with the Newtonian model. In atherosclerotic lesion models, the SDF model gives over 1 Pa higher WSS than the Newtonian model, a difference correlated with over twice as many adherent monocytes to endothelial cells from the Newtonian model compared to the SDF model.

  6. Hemodynamic analysis in an idealized artery tree: differences in wall shear stress between Newtonian and non-Newtonian blood models.

    Science.gov (United States)

    Weddell, Jared C; Kwack, JaeHyuk; Imoukhuede, P I; Masud, Arif

    2015-01-01

    Development of many conditions and disorders, such as atherosclerosis and stroke, are dependent upon hemodynamic forces. To accurately predict and prevent these conditions and disorders hemodynamic forces must be properly mapped. Here we compare a shear-rate dependent fluid (SDF) constitutive model, based on the works by Yasuda et al in 1981, against a Newtonian model of blood. We verify our stabilized finite element numerical method with the benchmark lid-driven cavity flow problem. Numerical simulations show that the Newtonian model gives similar velocity profiles in the 2-dimensional cavity given different height and width dimensions, given the same Reynolds number. Conversely, the SDF model gave dissimilar velocity profiles, differing from the Newtonian velocity profiles by up to 25% in velocity magnitudes. This difference can affect estimation in platelet distribution within blood vessels or magnetic nanoparticle delivery. Wall shear stress (WSS) is an important quantity involved in vascular remodeling through integrin and adhesion molecule mechanotransduction. The SDF model gave a 7.3-fold greater WSS than the Newtonian model at the top of the 3-dimensional cavity. The SDF model gave a 37.7-fold greater WSS than the Newtonian model at artery walls located immediately after bifurcations in the idealized femoral artery tree. The pressure drop across arteries reveals arterial sections highly resistive to flow which correlates with stenosis formation. Numerical simulations give the pressure drop across the idealized femoral artery tree with the SDF model which is approximately 2.3-fold higher than with the Newtonian model. In atherosclerotic lesion models, the SDF model gives over 1 Pa higher WSS than the Newtonian model, a difference correlated with over twice as many adherent monocytes to endothelial cells from the Newtonian model compared to the SDF model.

  7. Wall shear stress in intracranial aneurysms and adjacent arteries

    Institute of Scientific and Technical Information of China (English)

    Fuyu Wang; Bainan Xu; Zhenghui Sun; Chen Wu; Xiaojun Zhang

    2013-01-01

    Hemodynamic parameters play an important role in aneurysm formation and growth. However, it is difficult to directly observe a rapidly growing de novo aneurysm in a patient. To investigate possible associations between hemodynamic parameters and the formation and growth of intracranial aneurysms, the present study constructed a computational model of a case with an internal carotid artery aneurysm and an anterior communicating artery aneurysm, based on the CT angiography findings of a patient. To simulate the formation of the anterior communicating artery aneurysm and the growth of the internal carotid artery aneurysm, we then constructed a model that virtually removed the anterior communicating artery aneurysm, and a further two models that also progressively decreased the size of the internal carotid artery aneurysm. Computational simulations of the fluid dynamics of the four models were performed under pulsatile flow conditions, and wall shear stress was compared among the different models. In the three aneurysm growth models, increasing size of the aneurysm was associated with an increased area of low wall shear stress, a significant decrease in wall shear stress at the dome of the aneurysm, and a significant change in the wall shear stress of the parent artery. The wall shear stress of the anterior communicating artery remained low, and was significantly lower than the wall shear stress at the bifurcation of the internal carotid artery or the bifurcation of the middle cerebral artery. After formation of the anterior communicating artery aneurysm, the wall shear stress at the dome of the internal carotid artery aneurysm increased significantly, and the wall shear stress in the upstream arteries also changed significantly. These findings indicate that low wall shear stress may be associated with the initiation and growth of aneurysms, and that aneurysm formation and growth may influence hemodynamic parameters in the local and adjacent arteries.

  8. Doppler indicates of uterine artery Doppler velocimetry by placental location

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sung Shik; Park, Yong Won; Cho, Jae Sung; Kwon, Hye Kyeung; Kim, Jae Wook [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2001-09-15

    Our purpose was to investigate the relation between the vascular resistance of uterine artery and placental location and to establish the reference value of Doppler index in uterine artery by placental location. Placental location and flow velocity waveforms of both uterine arteries in 7,016 pregnant women after 18 weeks gestation were examined using color Doppler ultrasonography. Placental location was classified as central and lateral placental and the uterine artery with lateral placental were divided into ipsilateral uterine artery (same side of the placental) and contralateral uterine artery (opposite side of the placenta). The uterine artery with central placental was classified as the central uterine artery. Systolic-Diastolic ratio (S/D ratio) of uterine arteries by gestational weeks were calculated and compared with the placental location and perinatal outcomes. In the lateral placental group, the S/D ratio of the contralateral uterine artery was higher than the ipsilateral one (mean=2.08+0.34 vs 1.89+0.34, p=0.0001). S/D ratio of the uterine artery decreased during second trimester and the ratio after 27 weeks was a tendency to have a constant values(ipsilateral: 1.85+ 0.34, central : 1.96+ 0.40, contralateral: 2.01+0.54). S/D ratio of the uterine artery was affected by placental location. So when we evaluate Doppler spectrum of uterine artery, placental location should be considered and we established the reference value of Doppler index of uterine artery by placental location.

  9. Propagation of liquid surface waves over finite graphene structured arrays of cylinders

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Based on the multiple scattering method,this paper investigates a benchmark problem of the propagation of liquid surface waves over finite graphene (or honeycomb) structured arrays of cylinders.Comparing the graphene structured array with the square structured and with triangle structured arrays,it finds that the finite graphene structure can produce more complete band gaps than the other finite structures,and the finite graphene structure has less localized ability than the other finite structures.

  10. Coronary artery aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Koischwitz, D.; Harder, T.; Schuppan, U.; Thurn, P.

    1982-04-01

    Seven saccular coronary artery aneurysms have been demonstrated in the course of 1452 selective coronary artery angiograms. In six patients they were arterio-sclerotic; in one patient the aneurysm must have been congenital or of mycotic-embolic origin. The differential diagnosis between true aneurysms and other causes of vascular dilatation is discussed. Coronary artery aneurysms have a poor prognosis because of the possibility of rupture with resultant cardiac tamponade, or the development of thrombo-embolic myocardial infarction. These aneurysms can only be diagnosed by means of coronary angiography and require appropriate treatment.

  11. Coronary Artery Bypass

    Directory of Open Access Journals (Sweden)

    Kadri Ceberut

    2011-01-01

    Full Text Available Ancient schwannoma is a rare variant of neural tumors though rarely seen in the thorax. The combination with coronary artery diseases is also rare. Here we describe a 66 year-old male who had undergone one-stage combined surgery for thoracic ancient schwannomas removal and coronary artery disease. The masses were, respectively, 13 cm in the middle mediastinum and 5 cm in diameter originating from the intercostal nerve. The tumors were successfully removed using sternotomy, and then a coronary artery bypass grafting was performed. Here we discuss this rare tumor in relation to the relevant literature.

  12. 犬冠状动脉和脑动脉多巴胺受体亚型对比研究%Comparative studies on the characteristics of dopamine receptors in canines' coronary and cerebral arteries

    Institute of Scientific and Technical Information of China (English)

    王毅; 朱琳; 郑丽丽; 赵荣瑞

    2001-01-01

    Aim:To study the (DA) receptor subtypes and functional significance in canine coronary and cerebral arteries.Methods:Vascular ring technique was used for determining vasorelaxing response to fenoldopam and PBDA in canine coronary and cerebral arteries.Results:①DA1 receptors were distributed in the coronary and cerebral arteries,however,a great variation in their functional potency existed;②DA2 receptors were only present in the cerebral artery. Conclusion:To clarify the heterogeneity in subtype and responsiveness of DA receptors in the coronary and cerebral arteries may help to evaluate the physiological signifiance of DA receptors.%目的:对比分析犬冠状动脉和脑动脉多巴胺(DA)受体亚型类别与反应特性。方法:利用离体血管微量生物反应检测技术,测定多巴胺1(DA1)受体激动剂非诺多泮(Fenoldopam,FODA)和多巴胺2(DA2)受体激动剂propylbutyl-dopamine(PBDA)对冠状动脉和脑动脉血管环的舒张反应。结果:①冠状动脉和脑动脉均有DA1受体分布,但其分布密度存在明显差别;②脑动脉内既有DA1受体又有DA2受体分布;③用6-羟多巴胺(6-OHDA)处理后的实验进一步证实脑动脉存在有DA2受体。结论:冠状动脉和脑动脉DA受体亚型存在明显的异质性,阐明这种异质性将有助于了解多巴胺受体对冠脉循环和脑循环的不同生理反应。

  13. Renal arteries (image)

    Science.gov (United States)

    A renal angiogram is a test used to examine the blood vessels of the kidneys. The test is performed ... main vessel of the pelvis, up to the renal artery that leads into the kidney. Contrast medium ...

  14. Coronary Artery Bypass Surgery

    Science.gov (United States)

    ... t help, you may need coronary artery bypass surgery. The surgery creates a new path for blood to flow ... more than one bypass. The results of the surgery usually are excellent. Many people remain symptom-free ...

  15. Carotid Artery Disease

    Science.gov (United States)

    ... make them more vulnerable to damage. Tobacco use. Nicotine can irritate the inner lining of your arteries. ... your physical and mental capabilities such as strength, memory and speech. After that, your doctor may recommend: ...

  16. Pulmonary Arterial Hypertension

    Science.gov (United States)

    Pulmonary Arterial Hypertension What Is Pulmonary Hypertension? To understand pulmonary hypertension (PH) it helps to understand how blood ows throughout your body. While the heart is one organ, it ...

  17. Heritability of cilioretinal arteries

    DEFF Research Database (Denmark)

    Taarnhøj, Nina Charlotte; Munch, Inger C; Kyvik, Kirsten O;

    2005-01-01

    PURPOSE: To determine whether the presence of one or more cilioretinal arteries, a distinct element of the pattern of fundus vessels, is genetically programmed, influenced by environmental factors, or the result of random mechanisms of vascular development. METHODS: The fundi of 112 pairs...... environmental factors. CONCLUSIONS: The presence or absence of one or more cilioretinal arteries in healthy persons is markedly influenced by genetic factors....

  18. Finite unified theories

    Energy Technology Data Exchange (ETDEWEB)

    Mondragon, M [Inst. de Fisica, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, Mexico 01000 D.F. (Mexico); Zoupanos, G, E-mail: myriam@fisica.unam.m, E-mail: zoupanos@mail.cern.c [Physics Department, National Technical University of Athens, Zografou Campus: Heroon Polytechniou 9, 15780 Zografou, Athens (Greece)

    2009-06-01

    All-loop Finite Unified Theories (FUTs) are very interesting N=1 GUTs in which a complete reduction of couplings has been achieved. FUTs realize an old field theoretical dream and have remarkable predictive power. Reduction of dimensionless couplings in N=1 GUTs is achieved by searching for renormalization group invariant (RGI) relations among them holding beyond the unification scale. Finiteness results from the fact that there exists RGI relations among dimensionless couplings that guarantee the vanishing of the beta-functions in certain N=1 supersymmetric GUTS even to all orders. Furthermore, developments in the soft supersymmetry breaking sector of N=1 GUTs and FUTs lead to exact RGI relations also in this dimensionful sector of the theories. Of particular interest for the construction of realistic theories is a RGI sum rule for the soft scalar masses holding to all orders.

  19. Finite Quantum Gravity

    CERN Document Server

    Modesto, Leonardo

    2013-01-01

    We hereby present a class of multidimensional higher derivative theories of gravity that realizes an ultraviolet completion of Einstein general relativity. This class is marked by a "non-polynomal" entire function (form factor), which averts extra degrees of freedom (including ghosts) and improves the high energy behavior of the loop amplitudes. By power counting arguments, it is proved that the theory is super-renormalizable in any dimension, i.e. only one-loop divergences survive. Furthermore, in odd dimensions there are no counter terms for pure gravity and the theory turns out to be "finite." Finally, considering the infinite tower of massive states coming from dimensional reduction, quantum gravity is finite in even dimension as well.

  20. Effects of Hindlimb Unweighting on Arterial Contractile Responses in Mice

    Science.gov (United States)

    Ma, Jia; Ren, Xin-Ling; Purdy, Ralph E.

    2003-01-01

    The aim of this work was to determine if hindlimb unweighting in mice alters arterial contractile responses. Sixteen male C57B/6 mice and 16 male Chinese Kunming mice were divided into control and 3 weeks hindlimb unweighting groups, respectively. Using isolated arterial rings from different arteries of mouse, effects of 3 weeks hindlimb unweighting on arterial contractile responsiveness were examined in vitro. The results showed that, in arterial rings from both C57B/6 and Chinese Kunming mice, maximum isometric contractile tensions evoked by either KCl or phenylephrine were significantly lower in abdominal aortic, mesenteric arterial and femoral arterial rings from hindlimb unweighting, compared to control mice. However, the maximal contractile responses of common carotid rings to KCl and PE were not significantly different between control and hindlimb unweighting groups. The sensitivity (EC(sub 50)) of all arteries to KCl or PE showed no significant differences between control and hindlimb unweighting mice. These data indicated that 3 weeks hindlimb unweighting results in a reduced capacity of the arterial smooth muscle of the hindquarter to develop tension. In addition, the alterations in arterial contractile responses caused by hindlimb unweighting in mice are similar as those in rats. Our work suggested that hindlimb unweighting mouse model may be used as a model for the study of postflight cardiovascular deconditioning.

  1. Finite element modeling of a progressively expanding shape memory stent.

    Science.gov (United States)

    Thériault, Philippe; Terriault, Patrick; Brailovski, Vladimir; Gallo, Richard

    2006-01-01

    Cardiovascular stents are small cylindrical devices introduced in stenosed arteries to reopen the lumen and restore blood flow. However, this treatment presents complications, including restenosis, which is the reclosing of the artery's diameter after the insertion of a stent. The structure of the prosthesis penetrates into and injures the walls of the patient's artery. There then follows a proliferation of cells and the formation of scar tissue around the injury, similar to the scarring of other organic tissues. This reaction to the trauma subjects the artery to close. The proposed solution is to develop a Nitinol stent with a progressive expansion device made of polyethylene, allowing smooth and gradual contact between the stent and the artery's wall by creep effect. The purpose of this paper is to describe the technology and methodology for the numerical study of this kind of stent through the finite element method. ANSYS 8.0 software is used to perform the analysis. The Nitinol is modeled with a superelastic law and the polyethylene with a yield hardening law. A first simulation determines the final geometry of the stent laser cut from a small tube. A second simulation examines the behavior of the prosthesis during surgery and over the 4 weeks following the operation. The results demonstrate that a compromise can be reached between a limited expansion prior the inflation of the expandable balloon and a significant expansion by creep of the polymer rings.

  2. Investigation Of Interaction Between Nitinol Stent And A Vascular Plaque Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Recep Güneş

    2012-06-01

    Full Text Available In this study, the interaction between the Nitinol stent and the artery with plaque was investigated using finite element method. The occurring pressure values during the cardiac contraction (systolic and loosening (diastolic were applied as loading to the modeled system with Nitinol stent. In the light of the stress values, the suitability of the Nitinol stent in an artery with plaque was investigated. In the analysis, Nitinol stent was assumed to be shape memory alloy, and artery and plaque were assumed to behave linearly elastic. As a result, the stress and deformations in the plaque and artery due to the interference of Nitinol stent were discussed and concluded that the structure of artery with plaque can be expanded in accordance with Nitinol stent.

  3. Quantum mechanics in finite dimensional Hilbert space

    CERN Document Server

    de la Torre, A C

    2002-01-01

    The quantum mechanical formalism for position and momentum of a particle in a one dimensional cyclic lattice is constructively developed. Some mathematical features characteristic of the finite dimensional Hilbert space are compared with the infinite dimensional case. The construction of an unbiased basis for state determination is discussed.

  4. Nonstandard finite difference schemes for differential equations

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdizadeh Khalsaraei

    2014-12-01

    Full Text Available In this paper, the reorganization of the denominator of the discrete derivative and nonlocal approximation of nonlinear terms are used in the design of nonstandard finite difference schemes (NSFDs. Numerical examples confirming then efficiency of schemes, for some differential equations are provided. In order to illustrate the accuracy of the new NSFDs, the numerical results are compared with standard methods.

  5. Hemisphere jet mass distribution at finite Nc

    Directory of Open Access Journals (Sweden)

    Yoshikazu Hagiwara

    2016-05-01

    Full Text Available We perform the leading logarithmic resummation of nonglobal logarithms for the single-hemisphere jet mass distribution in e+e− annihilation including the finite-Nc corrections. The result is compared with the previous all-order result in the large-Nc limit as well as fixed-order perturbative calculations.

  6. Arterial Transit Time Mapping Obtained by Pulsed Continuous 3D ASL Imaging with Multiple Post-Label Delay Acquisitions: Comparative Study with PET-CBF in Patients with Chronic Occlusive Cerebrovascular Disease.

    Science.gov (United States)

    Tsujikawa, Tetsuya; Kimura, Hirohiko; Matsuda, Tsuyoshi; Fujiwara, Yasuhiro; Isozaki, Makoto; Kikuta, Ken-Ichiro; Okazawa, Hidehiko

    2016-01-01

    Arterial transit time (ATT) is most crucial for measuring absolute cerebral blood flow (CBF) by arterial spin labeling (ASL), a noninvasive magnetic resonance (MR) perfusion assessment technique, in patients with chronic occlusive cerebrovascular disease. We validated ASL-CBF and ASL-ATT maps calculated by pulsed continuous ASL (pCASL) with multiple post-label delay acquisitions in patients with occlusive cerebrovascular disease. Fifteen patients underwent MR scans, including pCASL, and positron emission tomography (PET) scans with 15O-water to obtain PET-CBF. MR acquisitions with different post-label delays (1.0, 1.5, 2.0, 2.5 and 3.0 sec) were also obtained for ATT correction. The theoretical framework of 2-compartmental model (2CM) was also used for the delay compensation. ASL-CBF and ASL-ATT were calculated based on the proposed 2CM, and the effect on the CBF values and the ATT correction characteristics were discussed. Linear regression analyses were performed both on pixel-by-pixel and region-of-interest bases in the middle cerebral artery (MCA) territory. There were significant correlations between ASL-CBF and PET-CBF both for voxel values (r = 0.74 ± 0.08, slope: 0.87 ± 0.22, intercept: 6.1 ± 4.9) and for the MCA territorial comparison in both affected (R2 = 0.67, y = 0.83x + 6.3) and contralateral sides (R2 = 0.66, y = 0.74x + 6.3). ASL-ATTs in the affected side were significantly longer than those in the contralateral side (1.51 ± 0.41 sec and 1.12 ± 0.30 sec, respectively, p <0.0005). CBF measurement using pCASL with delay compensation was feasible and fairly accurate even in altered hemodynamic states.

  7. An object-oriented modelling framework for the arterial wall.

    Science.gov (United States)

    Balaguera, M I; Briceño, J C; Glazier, J A

    2010-02-01

    An object-oriented modelling framework for the arterial wall is presented. The novelty of the framework is the possibility to generate customizable artery models, taking advantage of imaging technology. In our knowledge, this is the first object-oriented modelling framework for the arterial wall. Existing models do not allow close structural mapping with arterial microstructure as in the object-oriented framework. In the implemented model, passive behaviour of the arterial wall was considered and the tunica adventitia was the objective system. As verification, a model of an arterial segment was generated. In order to simulate its deformation, a matrix structural mechanics simulator was implemented. Two simulations were conducted, one for an axial loading test and other for a pressure-volume test. Each simulation began with a sensitivity analysis in order to determinate the best parameter combination and to compare the results with analogue controls. In both cases, the simulated results closely reproduced qualitatively and quantitatively the analogue control plots.

  8. Breast arterial calcification on mammogram: correlation with carotid arterial atherosclerosis on ultrasonogram

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Nam Ju; Suh, Jung Ho [School of Medicine, Ajou Univ., Suwon (Korea, Republic of); Kim, Ji Hyung [College of Medicine, KonYang Univ., Nonsan (Korea, Republic of)

    2002-01-01

    To investigate the incidence of breast arterial calcification in Korean women, and to determine its association with systemic diseases and carotid arterial atherosclerosis. One thousand seven hundred and thirteen female subjects who underwent mammography at a health care center between May 1999 and May 2000 were included in this study. Of the total, 172 were found to have breast arterial calcification, and were classified according to age. The coincidence of hypertension, diabetes mellitus and hyperlipidemia was examined in both the subject group and the control group selected on the same age basis. To investigate the presence and degree of carotid atherosclerosis, sonographic imaging was performed and the findings were compared between the two groups. The incidence of breast arterial calcification showed statistically significant differences according to age, with a higher incidence in older patients (p<0.05). However, there was no statistical difference in the incidence of hypertension, hyperlipidemia, and diabetes mellitus between groups. Carotid atherosclerosis was subjects more prevalent among subjects than in the control group (p<0.05), though there was no statistically significant difference in the degree of luminal stenosis. The most common pathologic cause of breast arterial calcification is arteriosclerosis. Breast arterial calcification is demonstrated at mammography, along with other clinical risk factors for atherosclerosis or coincidental neurologic symptoms. We stress that further evaluation of the carotid artery is necessary.

  9. Echocardiographic evaluation of external iliac artery Doppler waveform in patients with coronary artery disease.

    Science.gov (United States)

    Styczynski, Grzegorz; Szmigielski, Cezary; Kaczynska, Anna; Kuch-Wocial, Agnieszka

    2014-04-01

    Visual interpretation of the Doppler waveform in the common femoral or distal external iliac artery (EIA) was reported to be useful in screening for proximal peripheral artery occlusive disease (PAOD) in patients with lower limb ischemia. Commonly patients with coronary artery disease (CAD) referred for echocardiography have coexistent arterial pathology. Therefore, we decided to study whether echocardiographic evaluation of the distal EIA flow can be useful for detection of PAOD in patients with CAD. We studied 150 consecutive patients (pts) with CAD referred for echocardiography. At the end of an echocardiographic examination, evaluation of the flow in the distal EIA with an echocardiographic probe was performed. The Doppler waveform was classified as normal-with early diastolic flow reversal or abnormal-without early diastolic flow reversal. Echocardiographic findings were compared in a blinded fashion with the results of the ankle brachial index measurements (ABI). Based on the ABI ≤ 0.9, peripheral artery disease was diagnosed in 54 pts (36%) and abnormal external iliac Doppler waveform was found in 27 pts (18%). Sensitivity of abnormal external iliac Doppler waveform in predicting PAOD was 48%, specificity 99%, positive predictive value (PPV) 96%, and negative predictive value 77%. Peripheral arterial occlusive disease is common in patients with CAD referred for echocardiographic study. Echocardiographic assessment of distal EIA Doppler waveform has low sensitivity, but high specificity and high PPV in the diagnosis of peripheral arterial occlusive disease.

  10. Vibration Analysis of Beams by Spline Finite Element

    Institute of Scientific and Technical Information of China (English)

    YANG Hao; SUN Li

    2011-01-01

    In this paper,the spline finite element method is developed to investigate free vibration problems of beams.The cubic B-spline functions are used to construct the displacement field.The assembly of elements and the introduction of boundary conditions follow the standard finite element procedure.The results under various boundary conditions are compared with those obtained by the exact method and the finite difference method.It shows that the results are in excellent agreement with the analytical results and much more accurate than the results obtained by the finite difference method,especially for higher order modes.

  11. Finite rotation and nonlinear beam kinematics

    Science.gov (United States)

    Hodges, Dewey H.

    1987-01-01

    Standard means of representing finite rotation in rigid-body kinematics, including orientation angles, Euler parameters, and Rodrigues parameters, are reviewed and compared. General kinematical relations for a beam theory that treats arbitrarily large rotation are then presented. The standard methods of representing finite rotations are applied to these kinematical expressions, and comparison is made among the standard methods and additional methods found in the literature, such as quasi-coordinates and linear combinations of projection angles. The method of Rodrigues parameters is shown to stand out for both its simplicity and generality when applied to beam kinematics, a result that is really missing from the literature.

  12. Finite-Time Robust Stabilization for Stochastic Neural Networks

    Directory of Open Access Journals (Sweden)

    Weixiong Jin

    2012-01-01

    Full Text Available This paper is concerned with the finite-time stabilization for a class of stochastic neural networks (SNNs with noise perturbations. The purpose of the addressed problem is to design a nonlinear stabilizator which can stabilize the states of neural networks in finite time. Compared with the previous references, a continuous stabilizator is designed to realize such stabilization objective. Based on the recent finite-time stability theorem of stochastic nonlinear systems, sufficient conditions are established for ensuring the finite-time stability of the dynamics of SNNs in probability. Then, the gain parameters of the finite-time controller could be obtained by solving a linear matrix inequality and the robust finite-time stabilization could also be guaranteed for SNNs with uncertain parameters. Finally, two numerical examples are given to illustrate the effectiveness of the proposed design method.

  13. Coronary anomaly: the single coronary artery

    Institute of Scientific and Technical Information of China (English)

    QIN Xu-guang; XIONG Wei-guo; LU Chun-peng; GONG Cheng-jie; SHANG Li-hua

    2010-01-01

    @@ Single coronary artery (SCA), defined as an artery that arises from the arterial trunk and nourishes the entire myocardium, is rare. We report two cases of SCA, one is the right coronary artery (RCA) originating from the middle of left descending artery (LAD), and the other is the left main coronary artery (LMCA) arising from the proximal right coronary artery.

  14. 柔性基层和半刚性基层沥青路面有限元对比分析%Finite Element Comparative Analysis for Asphalt Pavement with Flexible Base Course and Semi-rigid Base Course

    Institute of Scientific and Technical Information of China (English)

    刘鹏飞; 杨刚; 梁乃兴

    2013-01-01

    Based on graded gravel bearing plate test this paper establishes formulae of constitutive model of nonlinear bearing capacity of base course materials of graded gravel and builds planar model of typical structure of asphalt pavement with flexible base course by means of ANSYS universal finite element software.The paper analyzes structural stress of asphalt pavement with aggregate base course and semirigid base course,including propagation laws of stress and strain of asphalt pavement with flexible base course under different stress conditions and propagation differences of stress and strain from asphalt pavement with semi-rigid base course.%通过级配碎石承载板试验建立级配碎石基层材料的非线性承载力本构模型公式,利用ANSYS通用有限元软件建立柔性基层沥青路面典型结构平面模型.对粒料基层沥青路面和半刚性基层沥青路面结构受力进行分析,包括柔性基层沥青路面在不同受力条件下应力、应变的传播规律以及与半刚性基层沥青路面之间的应力、应变传播差异.

  15. Coronary Artery and Pulmonary Artery Fistula Originated from Significant Stenosis in the Left Anterior Descending Artery

    Directory of Open Access Journals (Sweden)

    Alper Sami Kunt

    2013-01-01

    Full Text Available Coronary artery fistula (CAF is defined as a rare anomalous connection between a coronary artery and a major vessel or a cardiac chamber. We report a case of a left anterior descending coronary (LAD stenosis and coronary artery fistula between the LAD coronary artery and the pulmonary artery (PA. CAF is often diagnosed by coronary angiogram. We describe our diagnostic approach and review the literature on the epidemiology, the pathophysiology, the diagnostic modalities, and the treatment options.

  16. Mathematical model for blood flow through a bifurcated artery using couple stress fluid.

    Science.gov (United States)

    Srinivasacharya, D; Madhava Rao, G

    2016-08-01

    In this article, the blood flow through a bifurcated artery with mild stenosis is investigated taking blood as couple stress fluid. The artery configuring bifurcation is assumed to be symmetric about the axis of the artery and straight cylinders of finite length. The governing equations are non-dimensionalized and coordinate transformation is used to convert the irregular boundary to a regular boundary. The resulting system of equations is solved numerically using the finite difference method. The variation of shear stress, flow rate and impedance near the apex with pertinent parameters are studied graphically. It has been noticed that shear stress, flow rate and impedance have been changing suddenly with all the parameters on both sides of the apex. This occurs because of the backflow of the streaming blood at the onset of the lateral junction and secondary flow near the apex in the daughter artery.

  17. Propagation of dissection in a residually-stressed artery model.

    Science.gov (United States)

    Wang, Lei; Roper, Steven M; Hill, Nicholas A; Luo, Xiaoyu

    2017-02-01

    This paper studies dissection propagation subject to internal pressure in a residually-stressed two-layer arterial model. The artery is assumed to be infinitely long, and the resultant plane strain problem is solved using the extended finite element method. The arterial layers are modelled using the anisotropic hyperelastic Holzapfel-Gasser-Ogden model, and the tissue damage due to tear propagation is described using a linear cohesive traction-separation law. Residual stress in the arterial wall is determined by an opening angle [Formula: see text] in a stress-free configuration. An initial tear is introduced within the artery which is subject to internal pressure. Quasi-static solutions are computed to determine the critical value of the pressure, at which the dissection starts to propagate. Our model shows that the dissection tends to propagate radially outwards. Interestingly, the critical pressure is higher for both very short and very long tears. The simulations also reveal that the inner wall buckles for longer tears, which is supported by clinical CT scans. In all simulated cases, the critical pressure is found to increase with the opening angle. In other words, residual stress acts to protect the artery against tear propagation. The effect of residual stress is more prominent when a tear is of intermediate length ([Formula: see text]90[Formula: see text] arc length). There is an intricate balance between tear length, wall buckling, fibre orientation, and residual stress that determines the tear propagation.

  18. Assessment of distributed arterial network models.

    Science.gov (United States)

    Segers, P; Stergiopulos, N; Verdonck, P; Verhoeven, R

    1997-11-01

    The aim of this study is to evaluate the relative importance of elastic non-linearities, viscoelasticity and resistance vessel modelling on arterial pressure and flow wave contours computed with distributed arterial network models. The computational results of a non-linear (time-domain) and a linear (frequency-domain) mode were compared using the same geometrical configuration and identical upstream and downstream boundary conditions and mechanical properties. pressures were computed at the ascending aorta, brachial and femoral artery. In spite of the identical problem definition, computational differences were found in input impedance modulus (max. 15-20%), systolic pressure (max. 5%) and pulse pressure (max. 10%). For the brachial artery, the ratio of pulse pressure to aortic pulse pressure was practically identical for both models (3%), whereas for the femoral artery higher values are found for the linear model (+10%). The aortic/brachial pressure transfer function indicates that pressure harmonic amplification is somewhat higher in the linear model for frequencies lower than 6 Hz while the opposite is true for higher frequencies. These computational disparities were attributed to conceptual model differences, such as the treatment of geometric tapering, rather than to elastic or convective non-linearities. Compared to the effect of viscoelasticity, the discrepancy between the linear and non-linear model is of the same importance. At peripheral locations, the correct representation of terminal impedance outweight the computational differences between the linear and non-linear models.

  19. Classical and all-floating FETI methods for the simulation of arterial tissues

    CERN Document Server

    Augustin, Christoph M; Steinbach, Olaf

    2015-01-01

    High-resolution and anatomically realistic computer models of biological soft tissues play a significant role in the understanding of the function of cardiovascular components in health and disease. However, the computational effort to handle fine grids to resolve the geometries as well as sophisticated tissue models is very challenging. One possibility to derive a strongly scalable parallel solution algorithm is to consider finite element tearing and interconnecting (FETI) methods. In this study we propose and investigate the application of FETI methods to simulate the elastic behavior of biological soft tissues. As one particular example we choose the artery which is - as most other biological tissues - characterized by anisotropic and nonlinear material properties. We compare two specific approaches of FETI methods, classical and all-floating, and investigate the numerical behavior of different preconditioning techniques. In comparison to classical FETI, the all-floating approach has not only advantages co...

  20. Performance and scalability of finite-difference and finite-element wave-propagation modeling on Intel's Xeon Phi

    NARCIS (Netherlands)

    Zhebel, E.; Minisini, S.; Kononov, A.; Mulder, W.A.

    2013-01-01

    With the rapid developments in parallel compute architectures, algorithms for seismic modeling and imaging need to be reconsidered in terms of parallelization. The aim of this paper is to compare scalability of seismic modeling algorithms: finite differences, continuous mass-lumped finite elements a

  1. 薄壁箱体楼盖与密肋楼盖有限元对比分析%Study on comparative analysis of clamped thin-wall box floor and ribbed floor finite element

    Institute of Scientific and Technical Information of China (English)

    吴享树

    2012-01-01

    高强薄壁箱体楼盖是一种与密肋楼盖在结构上很相似的新型空心楼盖,为研究这两种楼盖结构受力性能的异同,进行了这两种楼盖的有限元对比分析,研究表明,薄壁箱体楼盖的刚度比密肋楼盖大,薄壁箱体楼盖的弹性内力比密肋楼盖的弹性内力小,且薄壁箱体楼盖的极限承载力也比密肋楼盖大,证明了这种新型空心楼盖的优越性。%High strength thin-wall floor is a new kind of hollow floor which is similar to ribbed floor in structure.To study on the differences of the mechanical properties of the two floor structure.In this paper,the finite element analysis of the two floor systems was carried out.Research showed that,thin-wall box floor is of larger rigidity than ribbed floor,the elastic force of thin-wall box floor is smaller than that of ribbed floor,and the thin-wall box floor has a better ultimate bearing capacity than ribbed floor,which proved the superiority of this new type of hollow floor.

  2. A method to quantify and visualize femoral head intraosseous arteries by micro-CT.

    Science.gov (United States)

    Qiu, Xing; Shi, Xiaotian; Ouyang, Jun; Xu, Dachuan; Zhao, Dewei

    2016-08-01

    We describe a technique for perfusing a barium sulphate suspension into the intraosseous artery. Following the perfusion of abarium sulphate suspension into 14 fresh lower limbs of Chinese cadavers, micro-CT scanning was applied to digitize, quantify and visualize the intraosseous arteries in the human femoral heads. Then, the femoral heads were removed and subjected to micro-CT scanning. The data were imported into the amira and mimics programs to reconstruct and quantify the intraosseous arteries. The femoral head intraosseous artery lengths, areas, volumes, and femoral head bone volumes were quantified. The artery densities and artery ratios were calculated and analysed with independent-samples t-tests. The intraosseous vasculature volume renderings were displayed as screenshots and videos made with amira. Many intraosseous artery study technologies were compared. The barium sulphate suspension was milky white in colour. The perfusion of the barium sulphate suspension followed by micro-CT scanning provided a good representation of the intraosseous artery. The femoral head intraosseous artery lengths, areas and volumes, and the femoral head bone volumes were displayed as the X¯±S . No differences were observed between the left and right femoral head intraosseous arteries in terms of the artery densities or artery ratios. The volume renderings and 3-D orthogonal projections displayed the overall distributions of the intraosseous arteries. The videos clearly demonstrated the entry sites of the nutrition-carrying arteries, their courses and branches, and the intraosseous arterial anastomoses. Our technique is the simplest and least time-consuming method of producing accurate vascular three-dimensional reconstructions. The perfusion of a barium sulphate suspension into intraosseous arteries combined with micro-CT scanning can deliver high-resolution 3-D digitized data and images of intraosseous arteries. This technique does not require bone decalcification or bone

  3. Computing with Hereditarily Finite Sequences

    CERN Document Server

    Tarau, Paul

    2011-01-01

    e use Prolog as a flexible meta-language to provide executable specifications of some fundamental mathematical objects and their transformations. In the process, isomorphisms are unraveled between natural numbers and combinatorial objects (rooted ordered trees representing hereditarily finite sequences and rooted ordered binary trees representing G\\"odel's System {\\bf T} types). This paper focuses on an application that can be seen as an unexpected "paradigm shift": we provide recursive definitions showing that the resulting representations are directly usable to perform symbolically arbitrary-length integer computations. Besides the theoretically interesting fact of "breaking the arithmetic/symbolic barrier", the arithmetic operations performed with symbolic objects like trees or types turn out to be genuinely efficient -- we derive implementations with asymptotic performance comparable to ordinary bitstring implementations of arbitrary-length integer arithmetic. The source code of the paper, organized as a ...

  4. Combinatorics of finite sets

    CERN Document Server

    Anderson, Ian

    2011-01-01

    Coherent treatment provides comprehensive view of basic methods and results of the combinatorial study of finite set systems. The Clements-Lindstrom extension of the Kruskal-Katona theorem to multisets is explored, as is the Greene-Kleitman result concerning k-saturated chain partitions of general partially ordered sets. Connections with Dilworth's theorem, the marriage problem, and probability are also discussed. Each chapter ends with a helpful series of exercises and outline solutions appear at the end. ""An excellent text for a topics course in discrete mathematics."" - Bulletin of the Ame

  5. Finite Density Fat QCD

    CERN Document Server

    Aloisio, R; Di Carlo, G; Galante, A; Grillo, A F

    2000-01-01

    Lattice formulation of Finite Baryon Density QCD is problematic from computer simulation point of view; it is well known that for light quark masses the reconstructed partition function fails to be positive in a wide region of parameter space. For large bare quark masses, instead, it is possible to obtain more sensible results; problems are still present but restricted to a small region. We present evidence for a saturation transition independent from the gauge coupling $\\beta$ and for a transition line that, starting from the temperature critical point at $\\mu=0$, moves towards smaller $\\beta$ with increasing $\\mu$ as expected from simplified phenomenological arguments.

  6. Additional renal arteries: incidence and morphometry.

    Science.gov (United States)

    Satyapal, K S; Haffejee, A A; Singh, B; Ramsaroop, L; Robbs, J V; Kalideen, J M

    2001-01-01

    Advances in surgical and uro-radiological techniques dictate a reappraisal and definition of renal arterial variations. This retrospective study aimed at establishing the incidence of additional renal arteries. Two subsets were analysed viz.: a) Clinical series--130 renal angiograms performed on renal transplant donors, 32 cadaver kidneys used in renal transplantation b) Cadaveric series--74 en-bloc morphologically normal kidney pairs. The sex and race distribution was: males 140, females 96; African 84, Indian 91, White 43 and "Coloured" 18, respectively. Incidence of first and second additional arteries were respectively, 23.2% (R: 18.6%; L: 27.6%) and 4.5% (R: 4.7%; L: 4.4%). Additional arteries occurred more frequently on the left (L: 32.0%; R: 23.3%). The incidence bilaterally was 10.2% (first additional arteries, only). The sex and race incidence (first and second additional) was: males, 28.0%, 5.1%; females, 16.4%, 3.8% and African 31.1%, 5.4%; Indian 13.5%, 4.5%; White 30.9%, 4.4% and "Coloured" 18.5%, 0%; respectively. Significant differences in the incidence of first additional arteries were noted between sex and race. The morphometry of additional renal arteries were lengths (cm) of first and second additional renal arteries: 4.5 and 3.8 (right), 4.9 and 3.7 (left); diameters: 0.4 and 0.3 (right), 0.3 and 0.3 (left). Detailed morphometry of sex and race were also recorded. No statistically significant differences were noted. Our results of the incidence of additional renal arteries of 27.7% compared favourably to that reported in the literature (weighted mean 28.1%). The study is unique in recording detailed morphometry of these vessels. Careful techniques in the identification of this anatomical variation is important since it impacts on renal transplantation surgery, vascular operations for renal artery stenosis, reno-vascular hypertension, Takayasu's disease, renal trauma and uro-radiological procedures.

  7. Implantable blood pressure sensor for analyzing elasticity in arteries

    Science.gov (United States)

    Franco-Ayala, Marco; Martínez-Piñón, Fernando; Reyes-Barranca, Alfredo; Sánchez de la Peña, Salvador; Álvarez-Chavez, José A.

    2009-03-01

    MEMS technology could be an option for the development of a pressure sensor which allows the monitoring of several electronic signals in humans. In this work, a comparison is made between the typical elasticity curves of several arteries in the human body and the elasticity obtained for MEMS silicon microstructures such as membranes and cantilevers employing Finite Element analysis tools. The purpose is to identify which types of microstructures are mechanically compatible with human arteries. The goal is to integrate a blood pressure sensor which can be implanted in proximity with an artery. The expected benefits for this type of sensor are mainly to reduce the problems associated with the use of bulk devices through the day and during several days. Such a sensor could give precise blood pressure readings in a continuous or periodic form, i.e. information that is especially important for some critical cases of hypertension patients.

  8. Is arterial wall-strain stiffening an additional process responsible for atherosclerosis in coronary bifurcations?: an in vivo study based on dynamic CT and MRI.

    Science.gov (United States)

    Ohayon, Jacques; Gharib, Ahmed M; Garcia, Alberto; Heroux, Julie; Yazdani, Saami K; Malvè, Mauro; Tracqui, Philippe; Martinez, Miguel-Angel; Doblare, Manuel; Finet, Gérard; Pettigrew, Roderic I

    2011-09-01

    Coronary bifurcations represent specific regions of the arterial tree that are susceptible to atherosclerotic lesions. While the effects of vessel compliance, curvature, pulsatile blood flow, and cardiac motion on coronary endothelial shear stress have been widely explored, the effects of myocardial contraction on arterial wall stress/strain (WS/S) and vessel stiffness distributions remain unclear. Local increase of vessel stiffness resulting from wall-strain stiffening phenomenon (a local process due to the nonlinear mechanical properties of the arterial wall) may be critical in the development of atherosclerotic lesions. Therefore, the aim of this study was to quantify WS/S and stiffness in coronary bifurcations and to investigate correlations with plaque sites. Anatomic coronary geometry and cardiac motion were generated based on both computed tomography and MRI examinations of eight patients with minimal coronary disease. Computational structural analyses using the finite element method were subsequently performed, and spatial luminal arterial wall stretch (LW(Stretch)) and stiffness (LW(Stiff)) distributions in the left main coronary bifurcations were calculated. Our results show that all plaque sites were concomitantly subject to high LW(Stretch) and high LW(Stiff), with mean amplitudes of 34.7 ± 1.6% and 442.4 ± 113.0 kPa, respectively. The mean LW(Stiff) amplitude was found slightly greater at the plaque sites on the left main coronary artery (mean value: 482.2 ± 88.1 kPa) compared with those computed on the left anterior descending and left circumflex coronary arteries (416.3 ± 61.5 and 428.7 ± 181.8 kPa, respectively). These findings suggest that local wall stiffness plays a role in the initiation of atherosclerotic lesions.

  9. Left Coronary Artery-Pulmonary Artery Fistula in Coronary Artery Disease

    Directory of Open Access Journals (Sweden)

    Orhan Veli Doğan

    2012-08-01

    Full Text Available Coroner artery fistula which is rare and congenital or acquired arise from whole coroner artery drainage all of cardiac chamber and great artery. Although coroner artery fistula is uncommon, it can cause significant mortality and morbidity rates. The article is presented which coroner artery disease and coroner-pulmonary artery fistula was accomplishment committed. Sixty three year-old male patient admitted to the hospital with chest pain. Non-ST myocardial infarction was diagnosed in the examinations. After coroner angiography, it was found coronary artery disease in addition between LAD proximal portion and main pulmonary artery fistula. Fistula repair and coronary bypass were performed successfully under cardiopulmonary bypass. Without hemodynamic problem in intensive care and service follow-up, the patient was discharged from the hospital in the seventh postoperative day. We think that surgical treatment of coronary fistulas in patients with coronary artery lesion is done at the earliest time would enable improvement in mortality and morbidity rates.

  10. Physical inactivity and arterial stiffness in COPD

    Directory of Open Access Journals (Sweden)

    Sievi NA

    2015-09-01

    Full Text Available Noriane A Sievi,1 Daniel Franzen,1 Malcolm Kohler,1,2 Christian F Clarenbach1 1Division of Pulmonology, University Hospital of Zurich, 2Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland Background: Arterial stiffness is an important predictor of cardiovascular risk besides classic cardiovascular risk factors. Previous studies showed that arterial stiffness is increased in patients with COPD compared to healthy controls and exercise training may reduce arterial stiffness. Since physical inactivity is frequently observed in patients with COPD and exercise training may improve arterial stiffness, we hypothesized that low daily physical activity may be associated with increased arterial stiffness. Methods: In 123 patients with COPD (72% men; mean [standard deviation] age: 62 [7.5] years; median [quartile] forced expiratory volume in 1 second 35 [27/65] %predicted, arterial stiffness was assessed by augmentation index (AI. Daily physical activity level (PAL was measured by an activity monitor (SenseWear Pro™ >1 week. The association between AI and PAL was investigated by univariate and multivariate regression analysis, taking into account disease-specific characteristics and comorbidities. Results: Patients suffered from moderate (35%, severe (32%, and very severe (33% COPD, and 22% were active smokers. Median (quartile PAL was 1.4 (1.3/1.5 and mean (standard deviation AI 26% (9.2%. PAL showed a negative association with AI (B=-9.32, P=0.017 independent of age, sex, blood pressure, and airflow limitation. Conclusion: In COPD patients, a higher PAL seems to favorably influence arterial stiffness and therefore may reduce cardiovascular risk. Clinical Trial Registration: www.ClinicalTrials.gov, NCT01527773 Keywords: activity monitor, airflow limitation, COPD, physical activity level

  11. Comparative study of image quality and radiation dose between prospective and retrospective ECG gating technique in coronary artery imaging with 64-slice spiral CT%64排螺旋CT冠状动脉成像的前瞻性与回顾性心电门控技术的图像质量及辐射剂量的比较研究

    Institute of Scientific and Technical Information of China (English)

    刘建新; 刘剑; 窦砚彬; 王继琛; 孙洪跃

    2009-01-01

    目的 研究前瞻性心电门控触发(prospective ECG-triggering)与回顾性心电门控(retrosp-ective ECG gating)两种技术方法行冠状动脉CTA检查时,对冠状动脉图像质量及辐射剂量的比较.方法 33名疑似冠状动脉疾病的患者分两组进行对比研究.前瞻组16例为前瞻性心电门控成像,心率小于65次/min;回顾组17例为回顾性心电门控成像,心率小于75次/min.记录两组的辐射剂量并统计分析,同时进行图像质量评价.结果 两组图像质量比较,差异无统计学意义(P0.05).前瞻性心电门控冠状动脉CTA的平均DLP 234.4 mGy·cm,占回顾性心电门控冠状动脉CTA的平均DLP 974.4 mGy·cm的24.1%.前瞻性心电门控冠状动脉CTA的患者的平均有效剂量为3.2 mSy,回顾心电门控冠状动脉CTA患者的为13.6 mSv,降低76.47%.结论 64排螺旋CT在前瞻性心电门控冠状动脉CTA与回顾性心电门控冠状动脉CTA比较可以获得相似的图像质量,可大幅降低患者的有效剂量对于不能接受高辐射剂量且心率较低的受检人群具有重要的临床价值.%Objective To compare the image quality and radiation dose between prospective ECG-trigering and retrospective ECG gating technique in coronary artery imaging. Methods 33 patients suspected coronary artery disease were included in this study and divided into experimental group (prospective ECG-triggering coronary artery imaging, heart rate < 65 bpm, 16 patients)and control group (retrospective ECG gating coronary artery imaging, heart rate < 75 bpm, 17 patients). Radiation dose was recorded for statistical analysis. At the same time, image quality was evaluated. Results There were no significant differences in image quality 3.2 msy. Effective dose reduced 76.47 %. Conclusions Prospective ECG gating coronary artery imaging can obtain the similar image quality compared with prospective ECG gating coronary artery imaging but the effective dose reduced 76.47 %. Prospective ECG

  12. Arterial hypertension and cancer.

    Science.gov (United States)

    Milan, Alberto; Puglisi, Elisabetta; Ferrari, Laura; Bruno, Giulia; Losano, Isabel; Veglio, Franco

    2014-05-15

    Arterial hypertension and cancer are two of the most important causes of mortality in the world; correlations between these two clinical entities are complex and various. Cancer therapy using old (e.g., mitotic spindle poisons) as well as new (e.g., monoclonal antibody) drugs may cause arterial hypertension through different mechanisms; sometimes the increase of blood pressure levels may be responsible for chemotherapy withdrawal. Among newer cancer therapies, drugs interacting with the VEGF (vascular endothelial growth factors) pathways are the most frequently involved in hypertension development. However, many retrospective studies have suggested a relationship between antihypertensive treatment and risk of cancer, raising vast public concern. The purposes of this brief review have then been to analyse the role of chemotherapy in the pathogenesis of hypertension, to summarize the general rules of arterial hypertension management in this field and finally to evaluate the effects of antihypertensive therapy on cancer disease.

  13. Safety and efficacy of coronary drug eluting stent for atherosclerotic stenosis of the small renal artery

    Institute of Scientific and Technical Information of China (English)

    LI Chun-jie; WU Zheng; YAN Hong-bing; WANG Jian; ZHAO Han-jun

    2009-01-01

    @@ Small diameter renal artery refers to the renal artery with the cross-section diameter less than 5 mm, the incidence of which is approximately 8%.1 Small diameter renal artery is common in patients with congenital multi-branch renal arteries, diabetes and multi-coronary artery lesions. Renal artery bare-mental stent (BMS) implantation is the standard treatment for ostial renal artery stenosis.2,3 However, the restenosis rate4-6 is too high and becomes one of the relative contraindications for small diameter renal artery stent implantation. Clinical trials (e.g. RAVEL,7,8 SIRIUS9 and TAXUS-IV10) have proved that drug eluting stent (DES), compared with BMS, can reduce the restenosis rate after the percutanous coronary intervention (PCI). And Huda et al11 claimed that DES had the better results than BMS in the treatment of obstructive superficial femoral artery disease. However,there are few studies involved restenosis after the renal artery intervention. We hypothesized that coronary DES applied in renal artery stenosis might inhibit intimal proliferation effectively as in coronary artery disease;therefore we evaluated the results of 25 patients with atherosclerotic renal artery stenosis treated using coronary DES to assess the safety and efficacy of coronary DES in patients with small renal artery stenotic lesions.

  14. Fifty-eight cases of ocular ischemic diseases caused by carotid artery stenosis

    Institute of Scientific and Technical Information of China (English)

    LUO Rong-jiang; LIU Shao-rui; LI Xiao-min; ZHUO Ye-hong; TIAN Zhen

    2010-01-01

    Background The blood supply to the eye comes from the retinal central vascular system of the ophthalmic artery and the ciliary vascular system. The ophthalmic artery stems from the ipsilateral internal carotid artery. If occlusion or stenosis occurs in the carotid artery, the blood perfusion to the ophthalmic artery becomes insufficient, leading to signs and symptoms of anterior and posterior ocular ischemia. The objective of this study was to evaluate the clinical characteristics and risk factors of ocular ischemic diseases caused by carotid artery stenosis.Methods This study was a retrospective review of 145 patients with carotid artery stenosis. Fifty-eight patients who had symptoms of ocular ischemic disease caused by carotid artery stenosis formed group A and the other 87 patients who only had carotid artery stenosis formed group B. We analyzed the causes and course of disease, and relative risk factors,by comparing the two groups.Results The degree of carotid artery stenosis in group A was higher than that in group B. And group A had a greater decrease of ophthalmic artery flow. Male, hypertension, hyperlipidemia, and smoking were significantly related to carotid artery stenosis. Amaurosis fugax was the most common ocular symptom in group A. The ocular ischemic diseases mainly included ischemic optic neuropathy, central/branch retinal artery occlusion, ophthalmoplegia externa, and ocular ischemic syndrome.Conclusions Carotid artery stenosis correlates with ocular ischemic diseases. Ophthalmologists must observe for ocular symptoms, which were the onset symptoms in some patients.

  15. Mechanical thrombectomy in basilar artery thrombosis

    DEFF Research Database (Denmark)

    Fesl, Gunther; Holtmannspoetter, Markus; Patzig, Maximilian;

    2014-01-01

    PURPOSE: Multiple endovascular devices have been used for mechanical thrombectomy (MT) in basilar artery occlusion (BAO) for >10 years. Based on a single-center experience during the course of one decade, we present data on safety and efficacy of previous MT devices compared with modern stent ret...

  16. Finite quantum gauge theories

    Science.gov (United States)

    Modesto, Leonardo; Piva, Marco; Rachwał, Lesław

    2016-07-01

    We explicitly compute the one-loop exact beta function for a nonlocal extension of the standard gauge theory, in particular, Yang-Mills and QED. The theory, made of a weakly nonlocal kinetic term and a local potential of the gauge field, is unitary (ghost-free) and perturbatively super-renormalizable. Moreover, in the action we can always choose the potential (consisting of one "killer operator") to make zero the beta function of the running gauge coupling constant. The outcome is a UV finite theory for any gauge interaction. Our calculations are done in D =4 , but the results can be generalized to even or odd spacetime dimensions. We compute the contribution to the beta function from two different killer operators by using two independent techniques, namely, the Feynman diagrams and the Barvinsky-Vilkovisky traces. By making the theories finite, we are able to solve also the Landau pole problems, in particular, in QED. Without any potential, the beta function of the one-loop super-renormalizable theory shows a universal Landau pole in the running coupling constant in the ultraviolet regime (UV), regardless of the specific higher-derivative structure. However, the dressed propagator shows neither the Landau pole in the UV nor the singularities in the infrared regime (IR).

  17. Acute arterial infarcts in patients with severe head injuries

    Directory of Open Access Journals (Sweden)

    Deepak Agrawal

    2012-01-01

    Full Text Available Aims and Objectives: To study the incidence, demographic profile, and outcome of patients with severe closed head injuries who develop acute arterial infarcts. Materials and Methods: Patients with severe head injury (Glasgow coma score (GCS ≤8 presenting within 8 h of injury in the Department of Neurosurgery over a period of 5 months were enrolled in the study. Patients with penetrating head injury, infarct due to herniation and iatrogenic arterial injuries were excluded from the study. Only arterial infarcts developing within 8 h of injury were included in the study. A computed tomography (CT head was done on all patients within 8 h of injury and repeated if necessary. Arterial infarct was defined as well-demarcated wedge-shaped hypodensity corresponding to an arterial territory on plain CT of the head. Outcome was assessed using Glasgow outcome score (GOS at 1 month post-injury or at death (whichever came earlier. Results: Forty-four patients of severe head injury were included in the study during the above period. Of these, four patients (9.1% had arterial infarcts on the initial CT scan. The male:female ratio was 1:3. The mean age was 54 years (range 3-85 years. Two patients had infarcts in the middle cerebral artery distribution and two in the superior cerebellar artery distribution. Poor outcome (GOS 1-3 was seen in 100% of the patients with arterial infarct compared to 52.5% (n=21 in patients with severe head injury without arterial infarct. Conclusions: A significant percentage of patients with severe head injury have arterial infarcts on admission, which may imply arterial injury. Our study shows that these patients have a poorer prognosis vis-a-vis patient without these findings.

  18. Elective vs non-elective radial artery grafts: comparing midterm results through 64-Slice computed tomography Enxertos de artéria radial eletivos vs emergência: comparando resultados em seguimento a médio prazo

    Directory of Open Access Journals (Sweden)

    Roberto Rocha-e-Silva

    2007-01-01

    Full Text Available BACKGROUND: Left internal thoracic artery to left anterior descending artery (LITA-LADA grafting has become a fundamental part of the coronary artery bypass graft procedure (CABG. This grafting in turn has led to an increased use of other arterial conduits, of which the radial artery (RA is most popular. Whether RA grafting can be used in the emergency patient is controversial. METHODS: 47 patients with critical stenosis (>70% in all target vessels underwent CABG with LITA and RA grafts from 1996 to 2003. Patients were divided into elective (23 patients and non-elective groups (24 patients with LITA and RA grafts per patient being similar in both groups. Of these 47 patients, 5 died from non-cardiac complications and 12 were unavailable. Thus, 30 patients (71% of survivors were studied by multidetector computed tomography. A total of 36 LITA and 64 RA grafts were studied. RESULTS: The RA patency rate for elective and non-elective grafts were 82% (31/38 and 85% (22/26, respectively (p=0.75. The RA had a similar patency rate for all target vessels ranging from 73% to 100%. Only one patient had a redo CABG and 29 (97% are free from angina or re-intervention. LITA-LADA had a 92% (11/12 and 100% (10/10 patency rate for elective and non-elective groups, respectively (p=0.37. The sequential LITA-diagonal-LADA in the elective group had a 50% (03/06 patency rate, which was significantly lower than the 100% (08/08 patency rate of the non-elective group (p=0.02. CONCLUSION: Radial Artery grafts can be used in both elective and non-elective patients with excellent results.INTRODUÇÃO: A anastomose da artéria torácica interna esquerda com a artéria descendente anterior (ATIE-DA se tornou parte fundamental da cirurgia de revascularização do miocárdio (RM. Esta técnica levou ao aumento de utilização de outros enxertos arteriais, entre os quais, a artéria radial (AR é muito usasa. Na literatura há controvérsia se a AR pode ser usada em pacientes

  19. 圆环形薄板大挠度变形有限元分析比较研究%Comparative Study of Finite Element of Large Deflection of Circular Thin Plates

    Institute of Scientific and Technical Information of China (English)

    陈杰平; 李进; 乔印虎

    2016-01-01

    Annular thin plate is an important part of automobile shock absorber,which belongs to the typical non-linear deformation of large deflection. Traditional calculation method will cause large errors,or complicated cal-culation which can not be used in engineering conveniently. With the aid of and modern engineering analysis software,the large deflection of circular thin plate of different shock absorbers specifications were studied using the method of finite element analysis. According to von Kármán differential equation,combining with Chien per-turbation method,the analytical expression of the large deflection were presented. Undetermined coefficients of the analytical expression were been fitting out. For different situations,such as fixed radial ratio,or inner/out-side diameter,the calculation analysis and error comparison were carried out. Numerical calculation showed that the method is reasonable and reliable,simple and quick,with an error below 3%,and precision is higher,which can meet with the needs of engineering design and analysis.%环形薄板是汽车减振器中的一个重要零件,属于典型的大挠度非线性变形,传统的计算方法要么产生误差较大,或者计算繁琐不利于工程应用。本文借助于现代分析软件,利用有限元分析方法对汽车减振器中不同规格环形薄板的大挠度变形情况进行了研究。根据von Kármán提出的微分方程,结合钱氏摄动法给出了求解大挠曲变形的解析表达式,拟合出了解析式中的待定系数的数学表达式,并针对固定半径比、内/外径等不同情况进行了计算分析和误差比较。数值计算证明,使用的方法合理可靠,求解精度高、简单快捷实用,误差在3%以下,完全可以满足工程设计分析的需要。

  20. Idiopathic pulmonary artery aneurysm.

    Science.gov (United States)

    Kotwica, Tomasz; Szumarska, Joanna; Staniszewska-Marszalek, Edyta; Mazurek, Walentyna; Kosmala, Wojciech

    2009-05-01

    Pulmonary artery aneurysm (PAA) is an uncommon lesion, which may be associated with different etiologies including congenital cardiovascular diseases, systemic vasculitis, connective tissue diseases, infections, and trauma. Idiopathic PAA is sporadically diagnosed by exclusion of concomitant major pathology. We report a case of a 56-year-old female with an idiopathic pulmonary artery dilatation identified fortuitously by echocardiography and confirmed by contrast-enhanced computed tomography. Neither significant pulmonary valve dysfunction nor pulmonary hypertension and other cardiac abnormalities which might contribute to the PAA development were found. Here, we describe echocardiographic and computed tomography findings and review the literature on PAA management.

  1. Arterial Windkessels in marine mammals.

    Science.gov (United States)

    Shadwick, R E; Gosline, J M

    1995-01-01

    In marine mammals, the aortic arch is enlarged relative to the descending aorta to varying degrees in different species. The ratio of maximal diameter of the arch to that of the thoracic aorta is about 2.3 in the harbour seal (Phoca vitulina), 3.6 in the Weddell seal (Leptonychotes weddelli) and 3.2 in the fin whale (Balaenoptera physalus), compared with only 1.4 in the dog. This anatomical specialisation probably provides increased volume capacitance in the arterial circulation as an adaptation to diving bradycardia. Data on the morphometric and mechanical properties of aortic tissues from seals and fin whale are compared. In the harbour seal, more than 80% of the volume change in the entire thoracic aorta that results from a pressure pulse occurs in the bulbous arch, and this is more than 90% in the Weddell seal and fin whale. The enhanced capacitance of the arch in the harbour seal is primarily due to its larger diameter, as the relative wall thickness and elasticity of the arch and thoracic aorta are the same. A similar situation appears to exist in the larger Weddell seal, although extrapolation of the pressure-volume curves suggests that the arch might be somewhat less stiff than the thoracic aorta. In addition to being greatly expanded, the aortic arch of the fin whale is also much more distensible than the relatively thin-walled and much stiffer descending aorta. At the estimated mean blood pressure, the elastic modulus of this vessel is 12 MPa, or 30 times that of the aortic arch. The major haemodynamic consequence of this type of arterial modification is that the aortic arch acts as a Windkessel, i.e. the capacitance of the aorta is increased significantly close to the heart, leading to a reduced characteristic impedance and probably reduced pulsatility in the descending aorta. In the extreme case of the whale, the arterial capacitance is shifted entirely to the arch, and the impedance change at the entrance to the thoracic aorta is so high that this

  2. Left Anterior Descending Artery-Pulmonary Artery Fistula

    Directory of Open Access Journals (Sweden)

    Turan Ege

    2011-12-01

    Full Text Available Despite the fact that coronary arteriovenous fistulas constitute approximately half (48% of coronary artery anomalies, they are rarely seen anomalies. In this report,we aim to present a coronary arteriovenous fistula case detected during a coronary angiography between left anterior descending artery and pulmonary artery.

  3. Pulmonary arterial hypertension in children after neonatal arterial switch operation

    NARCIS (Netherlands)

    Zijlstra, Willemijn Mh; Elmasry, Ola; Pepplinkhuizen, Shari; Ivy, D Dunbar; Bonnet, Damien; Lévy, Marilyne; Gavilan, Jose Luis; Torrent-Vernetta, Alba; Mendoza, Alberto; Del Cerro, Maria Jesus; Moledina, Shahin; Berger, Rolf M. F.

    2017-01-01

    OBJECTIVES: Paediatric pulmonary arterial hypertension (PAH) after neonatal arterial switch operation (ASO) for transposition of the great arteries (TGA) is a clinically recognised entity with an estimated incidence of 0.6%-1.0%. Nevertheless, a clinical characterisation is lacking. We present an in

  4. Femoropopliteal artery centerline interpolation using contralateral shape.

    Science.gov (United States)

    Tran, David N; Fleischmann, Dominik; Rakshe, Tejas; Roos, Justus E; Rosenberg, Jarrett; Straka, Matus; Napel, Sandy

    2007-09-01

    Curved planar reformation allows comprehensive visualization of arterial flow channels, providing information about calcified and noncalcified plaques and degrees of stenoses. Existing semiautomated centerline-extraction algorithms for curved planar reformation generation fail in severely diseased and occluded arteries. We explored whether contralateral shape information could be used to reconstruct centerlines through femoropopliteal occlusions. We obtained CT angiography data sets of 29 subjects (16m/13f, 19-86yo) without peripheral arterial occlusive disease and five consecutive subjects (1m/4f, 54-85yo) with unilateral femoropopliteal arterial occlusions. A gradient-based method was used to extract the femoropopliteal centerlines in nondiseased segments. Centerlines of the five occluded segments were manually determined by four experts, two times each. We interpolated missing centerlines in 2475 simulated occlusions of various occlusion lengths in nondiseased subjects. We used different curve registration methods (reflection, similarity, affine, and global polynomial) to align the nonoccluded segments, matched the end points of the occluded segments to the corresponding patent end points, and recorded maximum Euclidean distances to the known centerlines. We also compared our algorithm to an existing knowledge-based PCA interpolation algorithm using the nondiseased subjects. In the five subjects with real femoropopliteal occlusions, we measured the maximum Euclidean distance and the percentage of the interpolation that remained within a typical 3 mm radius vessel. In the nondiseased subjects, we found that the rigid registration methods were not significantly (pinterpolation of centerlines through arterial occlusions.

  5. Reduced artery diameters in Klinefelter syndrome.

    Science.gov (United States)

    Foresta, C; Caretta, N; Palego, P; Ferlin, A; Zuccarello, D; Lenzi, A; Selice, R

    2012-10-01

    Various epidemiological studies in relatively large cohorts of patients with Klinefelter syndrome (KS) described the increased morbidity and mortality in these subjects. Our aim was to study the structure and function of arteries in different districts to investigate in these subjects possible alterations. A total of 92 patients having non-mosaic KS, diagnosed in Centre for Human Reproduction Pathology at the University of Padova, and 50 age-matched healthy male controls were studied. Klinefelter syndrome subjects and controls evaluation included complete medical history, physical examination, measurement of concentrations of the reproductive hormones, lipidic and glycidic metabolism, AR function and sensitivity, ultrasound examinations (diameters, carotid intima-media thickness and brachial flow-mediated dilation) of brachial, common carotid and common femoral artery and abdominal aorta. Klinefelter syndrome patients showed significantly reduced artery diameters in all districts evaluated. On the contrary no statistically significant difference was found in cIMT and brachial FMD values between KS patients and controls. Furthermore, we found no statistically significant correlation of artery diameters with reproductive hormones, metabolic parameters, anthropometric measures and weighted CAG repeats. To our knowledge, this is the first study finding a reduced artery diameter in several districts in KS patients compared with that of normal male subjects and overlapping to that of female subjects. We have not an explanation for this phenomenon, even if a possible involvement of genes controlling the development of vascular system might be hypothesized, and further research is required to verify this hypothesis.

  6. Estudo comparativo da pressão arterial e da prevalência de hipertensão arterial em duas coortes sucessivas (1975-1976 de estudantes de 16 a 25 anos, Botucatu, SP, Brasil Blood pressure levels and hipertension prevalence in 16 to 25 year-old students in Botucatu, S. Paulo, Brazil. A comparative study of two successive cohorts, 1975-1976

    Directory of Open Access Journals (Sweden)

    Dináh Borges de Almeida

    1978-12-01

    Full Text Available Com o objetivo de determinar os níveis de pressão arterial e a prevalência de hipertensão arterial em uma população jovem, foram realizados pesquisas em dois anos sucessivos em 1.288 e 736 estudantes de Botucatu, SP (Brasil tendo sido comparados os resultados obtidos. As médias das pressões sistólicas da população estudada e dos dois grupos etários desta população (16 a 20 anos e 21 a 25 anos foram idênticas em ambos os anos, tendo as médias das pressões diastólicas diferido de no máximo 2 mmHg; as médias, tanto sistólicas quanto diastólicas, dos dois sexos e da parcela branca da população estudada quanto à idade e sexo também diferiram de no máximo 2 mmHg. As médias da população estudada e sua parcela branca, em ambos os anos, foram superiores no sexo masculino e no grupo etário de 21 a 25 anos. Na população negra e amarela houve disparidade de resultados entre 1975 e 1976, indicando influência da exiguidade do tamanho dos contigentes negro e amarelo desta população. A prevalência de hipertensão arterial (pressão sistólica igual ou maior que 140 mmHg e diastólica igual ou maior que 90 mmHg foi de 5,04% em 1975 e 6,22% em 1976, tendo sido em ambos os anos maior no sexo masculino do que no feminino e no grupo de 21 a 25 do que no de 16 a 20 anos.To determine the prevalence of hypertension and blood pressure levels in a young population group, two groups, one of 1288 students and another of 736, all from Botucatu, were investigated during two consecutive years, and the results were then compared. The mean values for systolic readings of the whole population, as for the two age groups (16 to 20 and 21 to 25 years old, were identical for both years studied; the diastolic mean values differed by 2 mmHg at most. The mean systolic and diastolic reading for both sexes and among the whites also differed by 2 mmHg at most. The mean values for the whole population and among the white population were higher for males

  7. Coronary artery anomalies in Turner Syndrome

    DEFF Research Database (Denmark)

    Viuff, Mette H; Trolle, Christian; Wen, Jan;

    2016-01-01

    BACKGROUND: Congenital heart disease, primarily involving the left-sided structures, is often seen in patients with Turner Syndrome. Moreover, a few case reports have indicated that coronary anomalies may be more prevalent in Turner Syndrome than in the normal population. We therefore set out...... to systematically investigate coronary arterial anatomy by computed tomographic coronary angiography (coronary CTA) in Turner Syndrome patients. METHODS: Fifty consecutive women with Turner Syndrome (mean age 47 years [17-71]) underwent coronary CTA. Patients were compared with 25 gender-matched controls. RESULTS......: Coronary anomaly was more frequent in patients with Turner Syndrome than in healthy controls [20% vs. 4% (p = 0.043)]. Nine out of ten abnormal cases had an anomalous left coronary artery anatomy (absent left main trunk, n = 7; circumflex artery originating from the right aortic sinus, n = 2). One case had...

  8. Pharmacological modulation of arterial stiffness.

    LENUS (Irish Health Repository)

    Boutouyrie, Pierre

    2011-09-10

    Arterial stiffness has emerged as an important marker of cardiovascular risk in various populations and reflects the cumulative effect of cardiovascular risk factors on large arteries, which in turn is modulated by genetic background. Arterial stiffness is determined by the composition of the arterial wall and the arrangement of these components, and can be studied in humans non-invasively. Age and distending pressure are two major factors influencing large artery stiffness. Change in arterial stiffness with drugs is an important endpoint in clinical trials, although evidence for arterial stiffness as a therapeutic target still needs to be confirmed. Drugs that independently affect arterial stiffness include antihypertensive drugs, mostly blockers of the renin-angiotensin-aldosterone system, hormone replacement therapy and some antidiabetic drugs such as glitazones. While the quest continues for \\'de-stiffening drugs\\

  9. Pulmonary artery sling: Case report

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Gil Hyun; Lee, Sun Wha; Cha, Sung Ho [Kyunghee University College of Medicine, Seoul (Korea, Republic of)

    1993-09-15

    Aberrant left-sided pulmonary artery(pulmonary artery sling) is an uncommon anomaly,which may cause significant respiratory abnormality. We report a case of pulmonary artery sling which is combined with persistent left superior vena cava and dextrocardia. This case were identified by esophagogram and CT and confirmed by MRI and angiography. We consider that MRI is a valuable new method for the diagnosis of aberrant left-sided pulmonary artery.

  10. Non deterministic finite automata for power systems fault diagnostics

    Directory of Open Access Journals (Sweden)

    LINDEN, R.

    2009-06-01

    Full Text Available This paper introduces an application based on finite non-deterministic automata for power systems diagnosis. Automata for the simpler faults are presented and the proposed system is compared with an established expert system.

  11. Mass-radius relations of white dwarfs at finite temperatures

    OpenAIRE

    Boshkayev, Kuantay; Rueda, Jorge A.; Ruffini, Remo; Zhami, Bakytzhan; Kalymova, Zhanerke; Balgimbekov, Galymdin

    2016-01-01

    We construct mass-radius relations of white dwarfs taking into account the effects of rotation and finite temperatures. We compare and contrast the theoretical mass-radius relations with observational data.

  12. Comparison of different precondtioners for nonsymmtric finite volume element methods

    Energy Technology Data Exchange (ETDEWEB)

    Mishev, I.D.

    1996-12-31

    We consider a few different preconditioners for the linear systems arising from the discretization of 3-D convection-diffusion problems with the finite volume element method. Their theoretical and computational convergence rates are compared and discussed.

  13. A comparative assessment of torque capabilities between lingual and labial brackets using three-dimension finite element%唇舌侧托槽转矩控制性能的有限元对比分析

    Institute of Scientific and Technical Information of China (English)

    黄思源; 周吉; 黄跃

    2016-01-01

    目的:分析唇舌侧托槽转矩控制性能的差异,同时探讨不同材质不同尺寸的弓丝对舌侧托槽转矩控制的影响规律。方法:建立左上尖牙到右上尖牙的唇舌侧托槽三维有限元模型,在弓丝尺寸及材质不同的情况下,模拟临床左上中切牙转矩加载±20°。结果:随着转矩角度的增大,唇舌侧托槽转矩值逐渐增大,舌侧托槽转矩值为唇侧托槽的3~5倍;0.48 mm ×0.64 mm 弓丝的转矩值大于0.43 mm ×0.64 mm;弓丝尺寸相同时,不锈钢丝(SS),β-钛丝(TMA),镍钛丝(NiTi),转矩值依次减小。结论:唇舌侧托槽转矩均随着转矩角度和弓丝的弹性模量的增大而增大;在相同的转矩角度下,舌侧托槽产生的转矩值大于唇侧托槽;舌侧托槽的转矩值与弓丝尺寸及材质有关。%Objective:To analyse the difference of torque performance between lingual and labial brackets as well as the influence of the archwires of different materials with different dimension on the torque capability of lingual brackets.Methods:The 3D finite mo-del of lingual and labial brackets from the right upper canine to the left upper canine was established,all brackets were with 0.56 mm slot size.The center of the bracket slot of the left upper central incisor was used as the central point and the two brackets were rotated clockwise and counterclockwise with a rotation angle of ±20°along the horizontal axis of bracket slot.The torque load on the left up-per central incisors with different materials and dimensions of the archwires was simulated.Results:The torque force of both lingual and labial brackets increased with the increase of rotation angle and the elastic modulus of archwire.The lingual archwire generated torque force was nearly 3 -5 times more than the labial system under the same torque angle.The torque value generated with 0.48 mm ×0.64 mm archwires was greater than 0.43 mm ×0.64 mm

  14. Intracranial artery dissection

    NARCIS (Netherlands)

    Sikkema, T.; Uyttenboogaart, Maarten; Eshghi, O.; De Keyser, J.; Brouns, R.; van Dijk, J.M.C.; Luijckx, G. J.

    2014-01-01

    The aim of this narrative review is to evaluate the pathogenesis, clinical features, diagnosis, treatment and prognosis of intracranial artery dissection (IAD). IAD is a rare and often unrecognized cause of stroke or subarachnoid haemorrhage (SAH), especially in young adults. Two types of IAD can be

  15. Popliteal artery entrapment syndrome

    DEFF Research Database (Denmark)

    Altintas, Ümit; Helgstrand, Ulf Johan Vilhelm; Hansen, Marc A;

    2013-01-01

    The purpose of this study was to report our experience with popliteal artery entrapment syndrome (PAES) with special emphasis on the applicability of duplex ultrasound scanning (DUS) when diagnosing PAES. In addition to examining the correlation between DUS and intraoperative findings...

  16. Arterial Emboli Complicating Cisplatin Therapy

    OpenAIRE

    Tait, Campbell D.; Rankin, Elaine M

    2012-01-01

    We report three cases of arterial emboli in patients with lung cancer treated with cisplatin chemotherapy. All three patients were managed without surgical intervention but subsequent oncological treatment was complicated by the sequelae of arterial emboli. We discuss the issues surrounding these patients and the importance of identifying patients at risk of arterial embolic phenomena with cisplatin treatment.

  17. Neoclassical toroidal plasma viscosity with effects of finite banana width for finite aspect ratio tokamaks

    Science.gov (United States)

    Shaing, K. C.; Sabbagh, S. A.

    2016-07-01

    Theory for neoclassical toroidal plasma viscosity has been developed to model transport phenomena, especially, toroidal plasma rotation for tokamaks with broken symmetry. Theoretical predictions are in agreement with the results of the numerical codes in the large aspect ratio limit. The theory has since been extended to include effects of finite aspect ratio and finite plasma β. Here, β is the ratio of the plasma thermal pressure to the magnetic field pressure. However, there are cases where the radial wavelength of the self-consistent perturbed magnetic field strength B on the perturbed magnetic surface is comparable to the width of the trapped particles, i.e., bananas. To accommodate those cases, the theory for neoclassical toroidal plasma viscosity is further extended here to include the effects of the finite banana width. The extended theory is developed using the orbit averaged drift kinetic equation in the low collisionality regimes. The results of the theory can now be used to model plasma transport, including toroidal plasma rotation, in real finite aspect ratio, and finite plasma β tokamaks with the radial wavelength of the perturbed symmetry breaking magnetic field strength comparable to or longer than the banana width.

  18. Value of contrast-enhanced CT in detecting arterial injury with pelvic fracture

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Keigo; Iwase, Toshiki; Ohshima, Takeshi; Tsuboi, Masaki; Sugiura, Sakae; Hara, Suguru [Okazaki City Hospital, Aichi (Japan)

    2000-04-01

    Computed tomography (CT) was used for detecting ongoing pelvic hemorrhage in patients with pelvic fracture, and for deciding an indication or transcatheter arterial embolization. The authors compared plane CT with contrast-enhanced CT to examine the value of contrast-enhanced CT in detecting arterial injury with pelvic fracture. The diagnosis of arterial injury was made by angiography. CT-determined hematoma was detected in 10 parts according to bleeding sites. Each hematoma was counted and compared with angiographic arterial injury. Contrast-enhanced CT was more useful than plane CT, but the hemorrhage sites determined by contrast-enhanced CT were not identical with those of angiographic arterial injuries. (author)

  19. Upregulation of 5-hydroxytryptamine receptor signaling in coronary arteries after organ culture.

    Directory of Open Access Journals (Sweden)

    Chun-Yu Deng

    Full Text Available BACKGROUND: 5-Hydroxytryptamine (5-HT is a powerful constrictor of coronary arteries and is considered to be involved in the pathophysiological mechanisms of coronary-artery spasm. However, the mechanism of enhancement of coronary-artery constriction to 5-HT during the development of coronary artery disease remains to be elucidated. Organ culture of intact blood-vessel segments has been suggested as a model for the phenotypic changes of smooth muscle cells in cardiovascular disease. METHODOLOGY/PRINCIPAL FINDINGS: We wished to characterize 5-HT receptor-induced vasoconstriction and quantify expression of 5-HT receptor signaling in cultured rat coronary arteries. Cumulative application of 5-HT produced a concentration-dependent vasoconstriction in fresh and 24 h-cultured rat coronary arteries without endothelia. 5-HT induced greater constriction in cultured coronary arteries than in fresh coronary arteries. U46619- and CaCl2-induced constriction in the two groups was comparable. 5-HT stimulates the 5-HT2A receptor and cascade of phospholipase C to induce coronary vasoconstriction. Calcium influx through L-type calcium channels and non-L-type calcium channels contributed to the coronary-artery constrictions induced by 5-HT. The contractions mediated by non-L-type calcium channels were significantly enhanced in cultured coronary arteries compared with fresh coronary arteries. The vasoconstriction induced by thapsigargin was also augmented in cultured coronary arteries. The decrease in Orai1 expression significantly inhibited 5-HT-evoked entry of Ca2+ in coronary artery cells. Expression of the 5-HT2A receptor, Orai1 and STIM1 were augmented in cultured coronary arteries compared with fresh coronary arteries. CONCLUSIONS: An increased contraction in response to 5-HT was mediated by the upregulation of 5-HT2A receptors and downstream signaling in cultured coronary arteries.

  20. Cerebral Arterial Fenestrations

    Science.gov (United States)

    Cooke, Daniel L; Stout, Charles E; Kim, Warren T; Kansagra, Akash P; Yu, John Paul; Gu, Amy; Jewell, Nicholas P; Hetts, Steven W; Higashida, Randall T; Dowd, Christopher F; Halbach, Van V

    2014-01-01

    Summary Arterial fenestrations are an anatomic variant with indeterminate significance. Given the controversy surrounding fenestrations we sought their prevalence within our practice along with their association with other cerebrovascular anomalies. We retrospectively reviewed 10,927 patients undergoing digital subtraction angiography between 1992 and 2011. Dictated reports were searched for the terms “fenestration” or “fenestrated” with images reviewed for relevance, yielding 228 unique cases. A Medline database search from February 1964 to January 2013 generated 304 citations, 127 cases of which were selected for analysis. Cerebral arterial fenestrations were identified in 228 patients (2.1%). At least one aneurysm was noted in 60.5% of patients, with an aneurysm arising from the fenestration in 19.6% of patients. Aneurysmal subarachnoid hemorrhage or non-aneurysmal subarachnoid hemorrhage were present in 60.1% and 15.8%, respectively. For the subset of patients with an aneurysm arising directly from a fenestration relative to those patients with an aneurysm not immediately associated with a fenestration, the prevalence of aneurysmal subarachnoid hemorrhage was 66.7% vs. 58.6% (p = 0.58). Fenestrations were more often within the posterior circulation (73.2%) than the anterior circulation (24.6%), though there was no difference in the prevalence of aneurysms within these groups (61.1% vs. 60.7%, p = 1.0). Cerebral arterial fenestrations are an anatomic variant more often manifesting at the anterior communicating arterial complex and basilar artery and with no definite pathological relationship with aneurysms. PMID:24976087

  1. Finite elements and finite differences for transonic flow calculations

    Science.gov (United States)

    Hafez, M. M.; Murman, E. M.; Wellford, L. C.

    1978-01-01

    The paper reviews the chief finite difference and finite element techniques used for numerical solution of nonlinear mixed elliptic-hyperbolic equations governing transonic flow. The forms of the governing equations for unsteady two-dimensional transonic flow considered are the Euler equation, the full potential equation in both conservative and nonconservative form, the transonic small-disturbance equation in both conservative and nonconservative form, and the hodograph equations for the small-disturbance case and the full-potential case. Finite difference methods considered include time-dependent methods, relaxation methods, semidirect methods, and hybrid methods. Finite element methods include finite element Lax-Wendroff schemes, implicit Galerkin method, mixed variational principles, dual iterative procedures, optimal control methods and least squares.

  2. A COMPARATIVE STUDY OF EFFICACY AND TOLERABILITY OF GENERIC AND ORIGINAL LOW-DOSE BISOPROLOL/HYDROCHLOROTHIAZIDE COMBINATION IN PATIENTS WITH ARTERIAL HYPERTENSION OF 1-2 DEGREES. RESULTS OF CLINICAL RANDOMIZED CROSSOVER STUDY

    Directory of Open Access Journals (Sweden)

    S. Yu. Martsevich

    2015-09-01

    Full Text Available Aim. To study the clinical equivalence of the two low-dose combined drugs on the base of generic and original bisoprolol and hydrochlorothiazide (HCTZ: BISANGIL® (Ozon, Russia and LODOZ® (NYCOMED, Merck KGaA, Germany in patients with arterial hypertension (HT of 1-2 degrees.Material and methods. Patients with HT of 1-2 degrees (n=30; 11 men and 19 women; aged 62.7±10.7 years were included in open crossover randomized trial. Duration of the study for each patient was 18 weeks: two 6-week courses of active treatment with each drug and two 2-week washout periods prior to each treatment course. The sequence of treatment courses was determined by randomization. Increase in bisoprolol dose and/or amlodipine addition occurred when effect was not sufficient. Therapy effectiveness (office blood pressure (BP, heart rate and safety was monitored at visits.Results. BP reduction after 6 weeks of therapy was -21.6±11.1/10.4±11.3 mm Hg in LODOZ® group and -22.9±9.7/11.7±13.5 mm Hg in BISANGIL® group (p<0.0001 for both, intergroup differences were insignificant. Target BP after 6 weeks of therapy was achieved in 26 (87% and 28 (93% patients, respectively.Conclusion. The therapeutic equivalence of the studied fixed combinations of bisoprolol/HCTZ was demonstrated in treatment of patients with HT of 1-2 degrees.

  3. Smoking and hyperlipidemia are important risk factors for coronary artery spasm

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Objective To investigate the role of coronary artery spasm in the etiology of chest pain lacking significant coronary stenosis and to identify the clinical risk factors related to coronary artery spasm. Methods Two hundred and seventy five patients with chest pain, but without significant coronary artery stenosis underwent the intracoronary acetylcholine test. Coronary artery spasm was diagnosed while coronary artery stenosis increased to 90% and was accompanied by the usual chest pain with or without ischemic changes on electrocardiogram. Logistic regression was employed to investigate the relationships between coronary artery spasm and sex, age, hypertension, diabetes mellitus, smoking, hyperlipidemia and results of electrocardiographic treadmill stress test. Left ventricular ejection fraction and end diastolic pressure were compared between spasm group and non-spasm group. Results Coronary artery spasm was detected in 103 out of 271 patients, a rate of 38%. Logistic regression analysis showed that smoking and hyperlipidemia increased the relative risk of coronary artery spasm 4.2 times and 2.3 times, respectively. There was a significantly negative relationship between diabetes mellitus and coronary artery spasm. Furthermore, there was no coronary artery spasm detected in left ventricular ejection fraction and end diastolic pressure. Conclusions Coronary artery spasm was one of the important etiological factors for patients with chest pain but no coronary artery stenosis. Smoking and hyperlipidemia were the main clinical risk factors for coronary artery spasm.

  4. Computational model of collagen turnover in carotid arteries during hypertension.

    Science.gov (United States)

    Sáez, P; Peña, E; Tarbell, J M; Martínez, M A

    2015-02-01

    It is well known that biological tissues adapt their properties because of different mechanical and chemical stimuli. The goal of this work is to study the collagen turnover in the arterial tissue of hypertensive patients through a coupled computational mechano-chemical model. Although it has been widely studied experimentally, computational models dealing with the mechano-chemical approach are not. The present approach can be extended easily to study other aspects of bone remodeling or collagen degradation in heart diseases. The model can be divided into three different stages. First, we study the smooth muscle cell synthesis of different biological substances due to over-stretching during hypertension. Next, we study the mass-transport of these substances along the arterial wall. The last step is to compute the turnover of collagen based on the amount of these substances in the arterial wall which interact with each other to modify the turnover rate of collagen. We simulate this process in a finite element model of a real human carotid artery. The final results show the well-known stiffening of the arterial wall due to the increase in the collagen content.

  5. Interval Finite Element Analysis of Wing Flutter

    Institute of Scientific and Technical Information of China (English)

    Wang Xiaojun; Qiu Zhiping

    2008-01-01

    The influences of uncertainties in structural parameters on the flutter speed of wing are studied. On the basis of the deterministic flutter analysis model of wing, the uncertainties in structural parameters are considered and described by interval numbers. By virtue of first-order Taylor series expansion, the lower and upper bound curves of the transient decay rate coefficient versus wind velocity are given. So the interval estimation of the flutter critical wind speed of wing can be obtained, which is more reasonable than the point esti- mation obtained by the deterministic flutter analysis and provides the basis for the further non-probabilistic interval reliability analysis of wing flutter. The flow chart for interval finite element model of flutter analysis of wing is given. The proposed interval finite element model and the stochastic finite element model for wing flutter analysis are compared by the examples of a three degrees of freedorn airfoil and fuselage and a 15° swepthack wing, and the results have shown the effectiveness and feasibility of the presented model. The prominent advantage of the proposed interval finite element model is that only the bounds of uncertain parameters axe required, and the probabilistic distribution densities or other statistical characteristics are not needed.

  6. Finite groups with transitive semipermutability

    Institute of Scientific and Technical Information of China (English)

    Lifang WANG; Yanming WANG

    2008-01-01

    A group G is said to be a T-group (resp. PT-group, PST-group), if normality (resp. permutability, S-permutability) is a transitive relation. In this paper, we get the characterization of finite solvable PST-groups. We also give a new characterization of finite solvable PT-groups.

  7. THE FINITE-STATE PLAYGROUND

    Directory of Open Access Journals (Sweden)

    Michael Hammond

    2008-06-01

    Full Text Available Finite-state methods are finding ever increasing use among linguists as a way of modeling phonology and morphology and as a method for manipulating and modeling text. This paper describes a suite of very simple finite-state tools written by the author that can be used to investigate this area and that can be used for simple analysis.

  8. Solution of Finite Element Equations

    DEFF Research Database (Denmark)

    Krenk, Steen

    An important step in solving any problem by the finite element method is the solution of the global equations. Numerical solution of linear equations is a subject covered in most courses in numerical analysis. However, the equations encountered in most finite element applications have some special...

  9. Quark Degrees of Freedom in Finite Nuclei

    CERN Document Server

    Tsushima, K; Thomas, A W; Tsushima, Kazuo; Saito, Koichi; Thomas, Anthony W.

    1996-01-01

    Properties of finite nuclei are investigated based on relativistic Hartree equations which have been derived from a relativistic quark model of the structure of bound nucleons. Nucleons are assumed to interact through the (self-consistent) exchange of scalar ($\\sigma$) and vector ($\\omega$ and and the rms charge radius in $^{40}$Ca. Calculated properties of static, closed-shell nuclei, as well as symmetric nuclear matter are compared with experimental data and with the results of Quantum Hadrodynamics (QHD).

  10. Probabilistic and quantum finite automata with postselection

    CERN Document Server

    Yakaryilmaz, Abuzer

    2011-01-01

    We prove that endowing a real-time probabilistic or quantum computer with the ability of postselection increases its computational power. For this purpose, we provide a new model of finite automata with postselection, and compare it with the model of L\\={a}ce et al. We examine the related language classes, and also establish separations between the classical and quantum versions, and between the zero-error vs. bounded-error modes of recognition in this model.

  11. Finite element model of needle electrode sensitivity

    Science.gov (United States)

    Høyum, P.; Kalvøy, H.; Martinsen, Ø. G.; Grimnes, S.

    2010-04-01

    We used the Finite Element (FE) Method to estimate the sensitivity of a needle electrode for bioimpedance measurement. This current conducting needle with insulated shaft was inserted in a saline solution and current was measured at the neutral electrode. FE model resistance and reactance were calculated and successfully compared with measurements on a laboratory model. The sensitivity field was described graphically based on these FE simulations.

  12. Implicit finite difference methods on composite grids

    Science.gov (United States)

    Mastin, C. Wayne

    1987-01-01

    Techniques for eliminating time lags in the implicit finite-difference solution of partial differential equations are investigated analytically, with a focus on transient fluid dynamics problems on overlapping multicomponent grids. The fundamental principles of the approach are explained, and the method is shown to be applicable to both rectangular and curvilinear grids. Numerical results for sample problems are compared with exact solutions in graphs, and good agreement is demonstrated.

  13. A comparison of the finite difference and finite element methods for heat transfer calculations

    Science.gov (United States)

    Emery, A. F.; Mortazavi, H. R.

    1982-01-01

    The finite difference method and finite element method for heat transfer calculations are compared by describing their bases and their application to some common heat transfer problems. In general it is noted that neither method is clearly superior, and in many instances, the choice is quite arbitrary and depends more upon the codes available and upon the personal preference of the analyst than upon any well defined advantages of one method. Classes of problems for which one method or the other is better suited are defined.

  14. STUDY OF PROFUNDA FEMORIS ARTERY OF HUMAN CADAVERS IN RAJKOT CITY, INDIA

    Directory of Open Access Journals (Sweden)

    Pradip R. Chauhan

    2015-03-01

    Full Text Available Background: The profunda femoris artery is the major branch of the femoral artery. It is at critical place in relation to femoral artery for various interventions. Aim: To study the origin of profunda femoris artery. And to compare the cross sectional area of profunda femoris artery between right and left limbs. Material and methods: In this cross sectional study, 51 human femoral triangles from 26 (18 male and 08 female human cadavers in P.D.U. Government Medical College, Rajkot were dissected and studied during regular dissection classes. Site of origin of profunda femoris artery was noted in relation to femoral artery. The distance of origin of profunda femoris artery from the midpoint of inguinal point was measured and noted. Circumference of profunda femoris artery at the level of origin was measured. The cross sectional area was calculated. Collected data was analyzed by standard statistical formulas with the help of Microsoft excel 2007 and Epi info TM 7 software. Result: Most common (52.95% cases site of origin was posterolateral from femoral artery. The mean distance of origin of profunda femoris artery from the midpoint of inguinal ligament was 30.17 mm. There was no significant difference in cross sectional area of right and left profunda femoris artery (at 95% confidence interval Conclusion: Profunda femoris artery is used for angiography, ultrasonography and cardiac catheterization also. It is the major blood supply of the thigh. Its relations with femoral artery, femoral vein and femoral nerve makes it important structure for clinicians. Variations in origin of profunda femoris artery must be considered to avoid complication like aneurism and faulty passage of the catheter. High origin of profunda femoris artery is more prone to damage while accessing femoral artery.

  15. Implication of the presence of a variant hepatic artery during the Whipple procedure

    Directory of Open Access Journals (Sweden)

    Mercedes Rubio-Manzanares-Dorado

    2015-07-01

    Full Text Available Introduction: The anatomical variants of the hepatic artery may have important implications for pancreatic cancer surgery. The aim of our study is to compare the outcome following a pancreatoduodenectomy (PD in patients with or without a variant hepatic artery arising from superior mesenteric artery. Material and methods: We reviewed 151 patients with periampullary tumoral pathology. All patients underwent oncological PD between January 2005 and February 2012. Our series was divided into two groups: Group A: Patients with a hepatic artery arising from superior mesenteric artery; and Group B: Patients without a hepatic artery arising from superior mesenteric artery. We expressed the results as mean ± standard deviation for continuous variables and percentages for qualitative variables. Statistical tests were considered significant if p < 0.05. Results: We identified 11 patients with a hepatic artery arising from superior mesenteric artery (7.3%. The most frequent variant was an aberrant right hepatic artery (n = 7, following by the accessory right hepatic artery (n = 2 and the common hepatic artery trunk arising from the superior mesenteric artery (n = 2. In 73% of cases the diagnosis of the variant was intraoperative. R0 resection was performed in all patients with a hepatic artery arising from superior mesenteric artery. There were no significant differences in the tumor resection margins and the incidence of postoperative complications. Conclusion: Oncological PD is feasible by the presence of a hepatic artery arising from superior mesenteric artery. The complexity of having it does not seem to influence in tumor resection margins, complications and survival.

  16. Massively Parallel Finite Element Programming

    KAUST Repository

    Heister, Timo

    2010-01-01

    Today\\'s large finite element simulations require parallel algorithms to scale on clusters with thousands or tens of thousands of processor cores. We present data structures and algorithms to take advantage of the power of high performance computers in generic finite element codes. Existing generic finite element libraries often restrict the parallelization to parallel linear algebra routines. This is a limiting factor when solving on more than a few hundreds of cores. We describe routines for distributed storage of all major components coupled with efficient, scalable algorithms. We give an overview of our effort to enable the modern and generic finite element library deal.II to take advantage of the power of large clusters. In particular, we describe the construction of a distributed mesh and develop algorithms to fully parallelize the finite element calculation. Numerical results demonstrate good scalability. © 2010 Springer-Verlag.

  17. Caliber-Persistent Artery

    Directory of Open Access Journals (Sweden)

    Sabrina Araújo Pinho Costa

    2015-01-01

    Full Text Available Caliber-persistent artery (CPLA of the lip is a common vascular anomaly in which a main arterial branch extends to the surface of the mucous tissue with no reduction in its diameter. It usually manifests as pulsatile papule, is easily misdiagnosed, and is observed more frequently among older people, suggesting that its development may involve a degenerative process associated with aging; CPLA is also characterized by the loss of tone of the adjacent supporting connective tissue. Although the diagnosis is clinical, high-resolution Doppler ultrasound is a useful noninvasive tool for evaluating the lesion. This report describes the case of a 58-year-old male patient who complained of a lesion of the lower lip with bleeding and recurrent ulceration. The patient was successfully treated in our hospital after a diagnosis of CPLA and is currently undergoing a clinical outpatient follow-up with no complaints.

  18. Finite element and finite difference methods in electromagnetic scattering

    CERN Document Server

    Morgan, MA

    2013-01-01

    This second volume in the Progress in Electromagnetic Research series examines recent advances in computational electromagnetics, with emphasis on scattering, as brought about by new formulations and algorithms which use finite element or finite difference techniques. Containing contributions by some of the world's leading experts, the papers thoroughly review and analyze this rapidly evolving area of computational electromagnetics. Covering topics ranging from the new finite-element based formulation for representing time-harmonic vector fields in 3-D inhomogeneous media using two coupled sca

  19. Case Report: Coronary arterial spasm in single right coronary artery

    Institute of Scientific and Technical Information of China (English)

    En-zhi JIA; Qi-jun SHAN; Zhi-jian YANG; Tie-bing ZHU; Lian-sheng WANG; Ke-jiang CAO; Wen-zhu MA

    2009-01-01

    We presented a case of anomalous single-coronary artery detected incidentally during routine coronary angiography. A 32-year-old male Chinese patient presented with recurrent pre-syncope and six episodes of syncope. Coronary angiography and coronary-computed tomography (CT)-angiography performed by a dual-source computed tomography (DSCT) revealed that the patient had a single large right coronary artery. A moderately large branch originated from the proximal part of the single right coronary artery and extended to the left, passing the anterior to the pulmonary artery, and divided into the anterior descending artery branch and circumflex branch at the base of the left auricular appendage. The episodes of the syncope were suspected to be caused by coronary arterial spasm, so this patient was on a regimen of 30 mg of diltiazem every 6 h and had no recurrence of syncope during follow-up.

  20. Análise comparativa entre a vascularização arterial ventricular e do nó sinoatrial em corações de cães Comparative analysis between both ventricular and sinoatrial node arterial vascularization in heart of dogs

    Directory of Open Access Journals (Sweden)

    Caio Biasi

    2013-01-01

    Full Text Available Utilizamos nesta pesquisa 40 corações de cães adultos, machos e fêmeas, de idades variadas, que não portavam nenhuma afecção cardíaca. Os corações tiveram as artérias coronárias injetadas, separadamente, com Neoprene Látex 450, corado com pigmento vermelho, e posteriormente dissecados. Em todas estas preparações verificamos que na vascularização dos ventrículos predominava a artéria coronária esquerda que fornecia os ramos interventriculares paraconal e subsinuoso. Já, a região ocupada pelo nó sinoatrial ficava mais frequentemente (17 vezes, 42,5% na dependência do ramo proximal atrial esquerdo ou de colateral deste vaso, oriundo do ramo circunflexo esquerdo, ou deste vaso associado ao ramo distal atrial direito (8 vezes, 20%, procedente do ramo circunflexo direito. Com menor frequência (14 vezes, 30%, a área tomada pelo nó sinoatrial, encontramos apenas colaterais do ramo circunflexo direito, mais exatamente somente o ramo distal atrial direito (10 vezes, 25%, apenas o ramo proximal atrial direito (3 vezes, 7,5% ou ainda exclusivamente o ramo intermédio atrial direito (1 vez, 2,5%. Em um único caso (1 vez, 2,5% no território do nó sinoatrial observamos apenas colateral do ramo circunflexo esquerdo, isto é o ramo distal atrial esquerdo. A análise destes resultados permite concluir, que nesta espécie não existe qualquer tipo de relação entre o tipo de vascularização dos ventrículos e a irrigação do nó sinoatrial. Sendo assim, considerar os ramos ventriculares isoladamente não é suficiente para um entendimento clínico-cirúrgico aplicado, uma vez que os ramos atriais apresentam uma importante contribuição para a vascularização do nó sinoatrial.We analyzed 40 hearts of adult dogs, males and females of different ages, without cardiac disease. The hearts had the coronary arteries inject using Neoprene Latex 450, colored with red pigment, and which was then dissected. In the ventricular

  1. Massive cerebral arterial air embolism following arterial catheterization

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C.W. [Northwestem University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States); Yang, B.P. [Northwestern University Feinberg School of Medicine, Department of Neurological Surgery, Chicago, IL (United States)

    2005-12-01

    Microscopic cerebral arterial air embolism (CAAE) has been described in many patients undergoing cardiac surgery as well as other invasive diagnostic and therapeutic procedures. However, massive CAAE is rare. We report a 42-year-old woman who initially presented with thalamic and basal ganglia hemorrhages. Shortly after a radial arterial catheter was inserted, the patient suffered a generalized seizure and CT demonstrated intra-arterial air in bilateral cerebral hemispheres. (orig.)

  2. Finite-time consensus of heterogeneous multi-agent systems

    Institute of Scientific and Technical Information of China (English)

    Zhu Ya-Kun; Guan Xin-Ping; Luo Xiao-Yuan

    2013-01-01

    We investigate the finite-time consensus problem for heterogeneous multi-agent systems composed of first-order and second-order agents.A novel continuous nonlinear distributed consensus protocol is constructed,and finite-time consensus criteria are obtained for the heterogeneous multi-agent systems.Compared with the existing results,the stationary and kinetic consensuses of the heterogeneous multi-agent systems can be achieved in a finite time respectively.Moreover,the leader can be a first-order or a second-order integrator agent.Finally,some simulation examples are employed to verify the efficiency of the theoretical results.

  3. COMPARATIVE STUDY OF NEW DRUG OF LONG ACTING METOPROLOL TARTRATE - EGILOK RETARD AND ORIGINAL DRUG OF METOPROLOL SUCCINATE – BETALOC ZOK IN PATIENTS WITH MILD TO MODERATE ARTERIAL HYPERTENSION

    Directory of Open Access Journals (Sweden)

    J. V. Lukina

    2005-01-01

    Full Text Available Aim. To study efficiency and safety of new drug of long acting metoprolol tartrate, “Egilok retard” (ER in patients with mild to moderate arterial hypertension (AH in comparison with the original drug of metoprolol succinat, “Betaloc ZOK” (BZ, possibility of reaching target blood pressure (BP level with treatment with each drug.Material and methods. 30 patients (11 men and 19 women with mild to moderate AH took part in randomized, open, cross over study. Previous antihypertensive treatment had been canceled for all the patients 10-14 days before the study started. Each patient by turns was treated during 6 weeks with ER and BZ 50-100 mg daily. After cancellation of the previous antihypertensive therapy, BZ and ER were prescribed (according to the randomization table in dose 50 mg daily. Drugs were taken once per day. 29 patients completed therapy with the first drug of randomization, 25 patients – with the second. After 2 weeks efficiency of treatment was assessed by target BP level achievement (< 140/90 mmHg. If efficiency of beta-adrenoblocker (BB was not sufficient, the dose of the drug was doubled to 100 mg daily, if target level was reached – the dose remained unchanged. Treatment with the settled dose was held within next 4 weeks. After 6-week treatment with the first randomized drug antihypertensive therapy was canceled for 10-14 days depending on the BB dose. At each visit office BP and heart rate were assessed, EKG was registered. Side-effects were registered according to the self-control diary, questionnaire results, examination and EKG data.Results. After 6-week treatment with ER and BZ average level of systolic BP reduced by 15,7 and 15,2 mmHg, of diastolic BP – by 8,0 and 4,5 mmHg, heart rate – by 4,1 and 4,3 beat/min respectively. Differences between antihypertensive and heart rate lowering effect of the studied drugs were not significant. Target BP level with treatment with both drugs was reached in approximately

  4. Compare and Research the Radiation dose and Image Quality on Dual Energy Dual Source Spiral CT Pulmonary Artery Imaging%双源双能量螺旋CT肺动脉成像辐射剂量与图像质量的对比研究

    Institute of Scientific and Technical Information of China (English)

    张筱双

    2015-01-01

    Objective To compare the difference of the radiation dose and image quality on dual energy dual source spiral CT pulmonary artery imaging.Methods 80 cases of pulmonary embolism patients in our hospital were selected as the research object. All patients were willing to accept CTPA examination, 40 cases in each group. A group used tube voltage 80/Sn140KV check, B group used tube voltage 100/Sn140KV examination, compared two groups’ pulmonary artery, pulmonary artery, the dorsal fat CT value, other indicators and CT image treatment subjective evaluation, calculation of signal to noise ratio (SNR), contrast to noise ratio (CNR) and effective dose (ED).Results The average CT value of A group’s pulmonary artery, mean CNR index were signiifcantly higher than those of group B(P<0.05), subjective CT image quality evaluation results show score were not signiifcantly different between A group and B group, but ed level of group A was signiifcantly lower than that of group B(P<0.05).Conclusion Dual source dual energy CT pulmonary artery imaging using scanning 80/Sn140 kV has high value in the diagnosis of CT images at the same time, and can greatly reduce the radiation dose during examination, which has clinical application and popularization value.%目的:对比第二代双源双能量螺旋CT肺动脉成像(CTPA)不同辐射剂量下CT图像质量的差异性。方法筛选我院收治的肺栓塞患者80例,作为研究对象。所有患者均自愿接受CTPA检查,每组40例,其中A组管电压80/Sn140KV检查,B组管电压100/Sn140KV检查,比较两组患者肺动脉主干、肺动脉段、背部脂肪CT值等指标,并对CT影像治疗进行主观评分,计算信噪比(SNR)、对比噪声比(CNR)、有效剂量(ED)等。结果 A组患者肺动脉平均CT值、平均CNR指标明显高于B组(P<0.05),主观CT影像质量评价结果显示A组与B组评分无显著差异,但A组ED水平明显低于B组(P<0.05)。结论

  5. Morphometric analysis of Willis circle arteries

    Directory of Open Access Journals (Sweden)

    Alma Voljevica

    2013-01-01

    Full Text Available Introduction: Willis arterial circle (circulus arteriosus cerebri Willisi is the most important part of the collateral circulatory system of the brain. It functions in normal and pathological situations such as valvular mechanism and thus allows optimal blood supply of all parts of the brain tissue, which reduces the risk of transient ischemic attack (TIA and stroke. The main pre-requisite for the normal function of the circle is its completeness and the lack of hypoplastic vessels. Materials and Methods: In this research, we used 100 angiograms of carotid system shown by serial angiography by Seldinger taken from the archives of the Department of Radiology, Clinical Center University of Sarajevo. For morphometric analysis of blood vessels, we used specially designed software program ELLIPSE (ViDiTo, Zoltan Tomoris, Kosice, Slovak Republic, tomori@saske.sk. In this way, it was possible to more easily store and analyze angiograms that were used for morphometric analysis. Results: In our study, larger diameters of blood vessels in Willis circle were observed in the younger subjects compared to older except the diameter of the internal carotid artery, which was about 0.2 to 0.3 mm larger in the older subjects. In both age groups among males, we recorded larger diameters of the internal carotid artery and segment before the circle of the posterior cerebral artery in relation to the female population, while the rear communicating artery in females was 0.1 mm wider in diameter compared to men in category of younger respondents.

  6. Automatic Construction of Finite Algebras

    Institute of Scientific and Technical Information of China (English)

    张健

    1995-01-01

    This paper deals with model generation for equational theories,i.e.,automatically generating (finite)models of a given set of (logical) equations.Our method of finite model generation and a tool for automatic construction of finite algebras is described.Some examples are given to show the applications of our program.We argue that,the combination of model generators and theorem provers enables us to get a better understanding of logical theories.A brief comparison betwween our tool and other similar tools is also presented.

  7. Finite element computational fluid mechanics

    Science.gov (United States)

    Baker, A. J.

    1983-01-01

    Finite element analysis as applied to the broad spectrum of computational fluid mechanics is analyzed. The finite element solution methodology is derived, developed, and applied directly to the differential equation systems governing classes of problems in fluid mechanics. The heat conduction equation is used to reveal the essence and elegance of finite element theory, including higher order accuracy and convergence. The algorithm is extended to the pervasive nonlinearity of the Navier-Stokes equations. A specific fluid mechanics problem class is analyzed with an even mix of theory and applications, including turbulence closure and the solution of turbulent flows.

  8. Doppler examination of the periorbital arteries adds valuable hemodynamic information in carotid artery disease

    DEFF Research Database (Denmark)

    Sillesen, H; Schroeder, T; Steenberg, H J;

    1987-01-01

    The periorbital flow direction and internal carotid artery (ICA) angiogram were compared to the ICA pressure gradient across the stenosis and the distal ICA pressure in 51 patients subjected to carotid endarterectomy. All 17 patients with inverted periorbital flow had stenoses exceeding 50%. The ...

  9. Arterial stiffness as a risk factor for coronary artery disease.

    Science.gov (United States)

    Liao, Josh; Farmer, John

    2014-02-01

    Hypertension is a major modifiable risk factor, and clinical trials have demonstrated that successful reduction of elevated blood pressure to target levels translates into decreased risk for the development of coronary artery disease, stroke, heart failure, and renal failure. The arterial system had previously been regarded as a passive conduit for the transportation of arterial blood to peripheral tissues. The physiologic role the arterial system was greatly expanded by the recognition of the central role of the endothelial function in a variety of physiologic processes. The role of arterial function and structure in cardiovascular physiology was expanded with the development of a variety of parameters that evaluate arterial stiffness. Markers of arterial stiffness have been correlated with cardiovascular outcomes, and have been classified as an emerging risk factor that provides prognostic information beyond standard stratification strategies involving hypertension, diabetes, obesity, dyslipidemia and smoking. Multiple epidemiologic studies have correlated markers of arterial stiffness such as pulse-wave velocity, augmentation index and pulse pressure with risk for the development of fatal and nonfatal cardiovascular events. Additionally, measurements of arterial stiffness had clarified the results of clinical trials that demonstrated differing impacts on clinical outcomes, despite similar reductions in blood pressure, as measured by brachial and sphygmomanometry.

  10. Finite volume form factors and correlation functions at finite temperature

    CERN Document Server

    Pozsgay, Balázs

    2009-01-01

    In this thesis we investigate finite size effects in 1+1 dimensional integrable QFT. In particular we consider matrix elements of local operators (finite volume form factors) and vacuum expectation values and correlation functions at finite temperature. In the first part of the thesis we give a complete description of the finite volume form factors in terms of the infinite volume form factors (solutions of the bootstrap program) and the S-matrix of the theory. The calculations are correct to all orders in the inverse of the volume, only exponentially decaying (residual) finite size effects are neglected. We also consider matrix elements with disconnected pieces and determine the general rule for evaluating such contributions in a finite volume. The analytic results are tested against numerical data obtained by the truncated conformal space approach in the Lee-Yang model and the Ising model in a magnetic field. In a separate section we also evaluate the leading exponential correction (the $\\mu$-term) associate...

  11. Coronary CT angiography in coronary artery disease: Opportunities and challenges

    Directory of Open Access Journals (Sweden)

    Zhonghua Sun

    2016-06-01

    Full Text Available Coronary CT angiography is widely recognised as a reliable imaging modality for the diagnosis of coronary artery disease. Coronary CT angiography not only provides excellent visualisation of anatomical changes in the coronary artery with high diagnostic value in the detection of lumen stenosis or occlusion, but also offers quantitative characterisation of coronary plaque components. Furthermore, coronary CT angiography allows myocardial perfusion imaging with diagnostic value comparable to the reference standard method. Coronary CT angiography-derived haemodynamic analysis has the potential to evaluate functional significance of coronary lesions. This review article aims to provide an overview of clinical applications of coronary CT angiography in coronary artery disease.

  12. Excess mortality during the first year after arterial trauma

    DEFF Research Database (Denmark)

    Thomsen, Lars; Lindholt, Jes; Roeder, Ole

    2015-01-01

    INTRODUCTION: Extant studies on arterial trauma originate from outside Denmark and their findings may therefore not apply to a Danish setting. The aim of the present study was to investigate the long-term mortality and clinical characteristics of patients with arterial trauma treated in Odense...... was compared with the expected mortality from the entire Danish population, matched to age, sex and date of trauma. RESULTS: A total of 231 patients were analysed. The median follow-up period was 6.9 years (range: 0-22.47). Traffic was the most common cause of arterial trauma, violence the least common...

  13. Coronary artery anomalies: prevalence and clinical profile in elderly patients

    Institute of Scientific and Technical Information of China (English)

    Gianluca Rigatelli; Giorgio Rigatelli; Mario Trivellato

    2004-01-01

    Objective Although congenital heart diseases are uncommon in the elderly, coronary artery anomalies may be incidentally discovered in old age. We sought to determine the incidence and clinical features of coronary artery anomalies (CAAs) in patients over 65 years of age. Patients and methods Medical records of patients undergoing coronary artery angiography in the years 1997-2002 at the Legnago General Hospital were retrospectively reviewed, The clinical profiles of all patients with CAAs and CAA subtypes were noted. Comparison between patients under and over 65 was performed. Data are given as mean standard deviation and as percentages. Results Sixtysix patients (1.21%, Female/Male 22/44, mean age 65.3 ± 10.6 years) out of the 5450 who underwent coronary angiography in the years 1997-2002 had CAAs. In mast cases (63%, 41/66 patients), the patients were over 65.CAAs were discovered incidentally in these elderly patients while undergoing coronary artery angiography for dilated cardiomyopathy, ischemic heart disease, and valvular heart disease in 75% of the cases (30/41 patients). Patients over 65 had more cardiac comorbidities and .a higher incidence of coronary atherosclerosis. Conclusions The angiographic incidence of CAAs in elderly patients is increasing as the population ages and this occurrence calls for a wider knowledge of the anatomy and pathophysiology of CAAs among geriatric cardiologists. Elderly patients seem to present with lower risk coronary anomalies (separated origin of left anterior descending coronary artery and circanfflex artery, origin of circumflex artery from the right sinus or the right coronary artery, double coronary artery)but have a higher risk profile compared to younger patients due to the frequency of cardiac comorbidities and superimposed coronary artery atherosclerosis.

  14. The finite element modeling of spiral ropes

    Institute of Scientific and Technical Information of China (English)

    Juan Wu

    2014-01-01

    Accurate understanding the behavior of spiral rope is complicated due to their complex geometry and complex contact conditions between the wires. This study proposed the finite element models of spiral ropes subjected to tensile loads. The parametric equations developed in this paper were implemented for geometric modeling of ropes. The 3D geometric models with different twisting manner, equal diameters of wires were generated in details by using Pro/ENGINEER software. The results of the present finite element analysis were on an acceptable level of accuracy as compared with those of theoretical and experimental data. Further development is ongoing to analysis the equivalent stresses induced by twisting manner of cables. The twisting manner of wires was important to spiral ropes in the three wire layers and the outer twisting manner of wires should be contrary to that of the second layer, no matter what is the first twisting manner of wires.

  15. Finite element modelling of solidification phenomena

    Indian Academy of Sciences (India)

    K N Seetharamu; R Paragasam; Ghulam A Quadir; Z A Zainal; B Sathya Prasad; T Sundararajan

    2001-02-01

    The process of solidification process is complex in nature and the simulation of such process is required in industry before it is actually undertaken. Finite element method is used to simulate the heat transfer process accompanying the solidification process. The metal and the mould along with the air gap formation is accounted in the heat transfer simulation. Distortion of the casting is caused due to non-uniform shrinkage associated with the process. Residual stresses are induced in the final castings. Simulation of the shrinkage and the thermal stresses are also carried out using finite element methods. The material behaviour is considered as visco-plastic. The simulations are compared with available experimental data and the comparison is found to be good. Special considerations regarding the simulation of solidification process are also brought out.

  16. Towards finite density QCD with Taylor expansions

    CERN Document Server

    Karsch, Frithjof; Wagner, Mathias; Wambach, Jochen

    2011-01-01

    We analyze general convergence properties of the Taylor expansion of observables to finite chemical potential in the framework of an effective 2+1 flavor Polyakov-quark-meson model. To compute the required higher order coefficients a novel technique based on algorithmic differentiation has been developed. Results for thermodynamic observables as well as the phase structure obtained through the series expansion up to 24th order are compared to the full model solution at finite chemical potential. The available higher order coefficients also allow for resummations, e.g. Pade series, which improve the convergence behavior. In view of our results we discuss the prospects for locating the QCD phase boundary and a possible critical endpoint with the Taylor expansion method.

  17. Arterial responses during migraine headache

    DEFF Research Database (Denmark)

    Iversen, Helle Klingenberg; Nielsen, T H; Olesen, J

    1990-01-01

    The superficial temporal artery has been thought to be the main focus of pain during migraine attacks, but its diameter has never been measured directly. The use of a new, high-resolution ultrasound machine to measure arterial size in 25 migraine patients with unilateral head pain showed...... that the lumen was wider on the painful than on the non-painful side during a migraine attack. The diameters of both radial arteries and the temporal artery on the non-painful side were smaller during than between attacks. The generalised vasoconstriction was not shared by the temporal artery on the affected...... side, which suggests a local vasodilatory response. The findings suggest that cephalic arteries may play a role in migraine pathogenesis....

  18. True aneurysm of brachial artery.

    Science.gov (United States)

    Hudorović, Narcis; Lovričević, Ivo; Franjić, Dario Bjorn; Brkić, Petar; Tomas, Davor

    2010-10-01

    True upper extremity peripheral artery aneurysms are a rarely encountered arterial disorder. Following computer-tomography angiographic (CT-a) imaging examination, true saccular aneurysm, originating from the left brachial artery was diagnosed in the 77-year-old female without history of trauma. The aneurysm was resected by surgical intervention, and primary repair of the brachial artery was performed by interposition of a part of great saphenous vein harvested from the left groin and creation of two end-to-end anastomoses between interposition graft and previously resected part of brachial artery. No complication was observed during the follow-up. Surgical intervention for upper extremity aneurysms should be initiated without delay. Factors combined with minimal morbidity associated with repair suggest that surgical repair should be performed routinely for true upper extremity arterial aneurysms.

  19. Finite Field Arithmetic Architecture Based on Cellular Array

    Directory of Open Access Journals (Sweden)

    Kee-Won Kim

    2015-05-01

    Full Text Available Recently, various finite field arithmetic structures are introduced for VLSI circuit implementation on cryptosystems and error correcting codes. In this study, we present an efficient finite field arithmetic architecture based on cellular semi-systolic array for Montgomery multiplication by choosing a proper Montgomery factor which is highly suitable for the design on parallel structures. Therefore, our architecture has reduced a time complexity by 50% compared to typical architecture.

  20. Average dynamics of a finite set of coupled phase oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Dima, Germán C., E-mail: gdima@df.uba.ar; Mindlin, Gabriel B. [Laboratorio de Sistemas Dinámicos, IFIBA y Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 1, Ciudad Universitaria, Buenos Aires (Argentina)

    2014-06-15

    We study the solutions of a dynamical system describing the average activity of an infinitely large set of driven coupled excitable units. We compared their topological organization with that reconstructed from the numerical integration of finite sets. In this way, we present a strategy to establish the pertinence of approximating the dynamics of finite sets of coupled nonlinear units by the dynamics of its infinitely large surrogate.

  1. Intracranial arterial anatomy: evaluation by computed tomography angiography; Anatomia arterial intracraniana: avaliacao por angiotomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Regattieri, Neysa Aparecida Tinoco, E-mail: neysa@utfpr.edu.b [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Haetinger, Rainer Guilherme; Liberti, Edson Aparecido [Universidade de Sao Paulo (ICB III/USP), SP (Brazil). Inst. de Ciencias Biomedicas; Piske, Ronie Leo [Hospital Beneficencia Portuguesa de Sao Paulo, SP (Brazil)

    2010-07-01

    By many decades, the intracranial arteries study was realized exclusively by angiography through selective arterial catheterization. Nowadays, with the technologic evaluation of computerized tomography devices with multi detectors allowing acquisitions with even more thinner slices, higher speed and better resolution, it had appeared a new modality of investigation: the computed tomography angiography, less invasive and with minor morbidity than conventional arteriography. Many studies in the literature have been analyzing the sensibility of the new method for the detection of intracranial aneurysms and comparing them with the conventional arteriography. There is a necessity to recognize the normal intracranial arterial anatomy and its variations using images obtained from multiplanar reformations, in order to give important information for surgeries strategies, such as wall calcifications, aneurismatic neck position and relationships with surrounding anatomical structures. (author)

  2. The right hepatic artery syndrome

    Institute of Scientific and Technical Information of China (English)

    Kazumi Miyashita; Katsuya Shiraki; Takeshi Ito; Hiroki Taoka; Takeshi Nakano

    2005-01-01

    Various benign and malignant conditions could cause biliary obstruction. Compression of extrahepatic bile duct (EBD) by right hepatic artery was reported as a right hepatic artery syndrome but all cases were compressed EBD from stomach side. Our case compressed from dorsum was not yet reported, so it was thought to be a very rare case. We present here the first case of bile duct obstruction due to the compression of EBD from dorsum by right hepatic artery.

  3. Drug-eluting stents in renal artery stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Zaehringer, M. [Marienhospital Stuttgart, Department of Radiology, Stuttgart (Germany); Pattynama, P.M.T. [Erasmus MC-University Medical Center Rotterdam, Rotterdam (Netherlands); Talen, A. [genae associates nv, Antwerp (Belgium); Sapoval, M. [Hopital Europeen Georges Pompidou, Service de Radiologie Cardio-Vasculaire, Paris (France); Inserm U 780 epidemiologie Cardio Vasculaire, Paris (France)

    2008-04-15

    Because of higher acute and long-term success rates compared with balloon angioplasty alone, percutaneous stent implantation has become an accepted therapy for the treatment of atherosclerotic renal artery stenosis. Restenosis rates after successful renal stent placement vary from 6 up to 40%, depending on the definition of restenosis, the diameter of the treated vessel segment and comorbidities. The safety and efficacy of drug-eluting stents for the treatment of renal-artery stenosis is poorly defined. The recently published GREAT study is the only prospective study, comparing bare-metal and sirolimus-coated low profile stent systems in renal artery stenosis, showing a relative risk reduction of angiographic binary in-stent restenosis by 50%. This is an opinion paper on indications, current treatment options and restenosis rates following renal artery stenting and the potential use of drug-eluting stents for this indication. (orig.)

  4. Anatomical variation of the origin of the left vertebral artery

    Directory of Open Access Journals (Sweden)

    Patasi B

    2009-08-01

    Full Text Available This paper presents and describes the anatomical variation of the left vertebral artery originating from the arch of aorta as a case report. This variation was found in one of the cadavers at the Division of Clinical and Functional Anatomy, Faculty of Medicine, University of Ottawa. During routine dissection of a male cadaver, in the superior mediastinum and the neck we observed an atypical origin of the left vertebral artery. Atypical origin was compared to the typical origin of the left vertebral artery in the anatomical literature. We compared our findings with different possible variations of the origin of the left vertebral artery reported in the literature. The clinical importance of the variation is discussed.

  5. Combinatorial Properties of Finite Models

    CERN Document Server

    Hubicka, Jan

    2010-01-01

    We study countable embedding-universal and homomorphism-universal structures and unify results related to both of these notions. We show that many universal and ultrahomogeneous structures allow a concise description (called here a finite presentation). Extending classical work of Rado (for the random graph), we find a finite presentation for each of the following classes: homogeneous undirected graphs, homogeneous tournaments and homogeneous partially ordered sets. We also give a finite presentation of the rational Urysohn metric space and some homogeneous directed graphs. We survey well known structures that are finitely presented. We focus on structures endowed with natural partial orders and prove their universality. These partial orders include partial orders on sets of words, partial orders formed by geometric objects, grammars, polynomials and homomorphism orders for various combinatorial objects. We give a new combinatorial proof of the existence of embedding-universal objects for homomorphism-defined...

  6. Language dynamics in finite populations.

    Science.gov (United States)

    Komarova, Natalia L; Nowak, Martin A

    2003-04-01

    Any mechanism of language acquisition can only learn a restricted set of grammars. The human brain contains a mechanism for language acquisition which can learn a restricted set of grammars. The theory of this restricted set is universal grammar (UG). UG has to be sufficiently specific to induce linguistic coherence in a population. This phenomenon is known as "coherence threshold". Previously, we have calculated the coherence threshold for deterministic dynamics and infinitely large populations. Here, we extend the framework to stochastic processes and finite populations. If there is selection for communicative function (selective language dynamics), then the analytic results for infinite populations are excellent approximations for finite populations; as expected, finite populations need a slightly higher accuracy of language acquisition to maintain coherence. If there is no selection for communicative function (neutral language dynamics), then linguistic coherence is only possible for finite populations.

  7. Comparative study of lower extremity CTA and enhanced MRA in patients with arterial occlusive disease of lower extremity%双下肢CTA和增强MRA在双下肢动脉硬化闭塞症中的对比研究

    Institute of Scientific and Technical Information of China (English)

    黄德珍; 徐向阳; 周红梅; 李莹; 张慧娟; 丁蓓; 柳湘洁

    2016-01-01

    Objective:To comparatively study the value and advantage of CT angiography (CTA) and Contrast‐enhanced magnetic resonance angiography (CE‐MRA ) in diagnosing the lower extremity arteriosclerosis obliterans syndrome (LEASO) ,compared with digital subtraction angiography (DSA) as a gold standard .Methods :The images of CTA and CE‐MRA of 40 cases proven LEASO by DSA and clinical symptoms were analyzed ,and the diagnosis accuracy of obliteration sites and stenosis degree checked by CTA and CE‐MRA were analyzed by statistical methods .Results :The stenosis degree of 305 arteries diagnosed by DSA were more than 50% ,including 63 iliac ar‐teries ,128 femoral and popliteal arteries and 114 tibiofibular arteries .The consistent rate of CTA and CE‐MRA in the diagnosis of vascular lesions was 90 .82% and 84 .59% respectively ,and the consistency of CTA and CE‐MRA compared with DSA in diagnosing each segment of artery was higher ,and there was no significant difference(P>0 . 05) .The coincidence rate of assessment of stenosis degree by CTA compared with DSA was 90 .51% ,which was higher than that by CE‐MRA ,and the difference was significant (P<0 .01) .Conclusion: It is valuable o f both CTA and CE‐MRA in diagnosing the LEASO ,and both them has the same value in the location diagnosis .But the assessment accuracy of stenosis degree by CTA is higher ,which can be as a reliable diagnostic method of LEASO .%目的:探讨CT 动脉血管成像(CTA)和增强磁共振血管成像(CE‐MRA)在双下肢动脉硬化闭塞症(LEASO )诊断中的价值和优势。方法:对本院经DSA 和临床确诊为LEASO的40例患者的下肢CTA和CE‐MRA的图像进行分析,并用统计学方法分析两种检查方法对闭塞部位诊断及评估狭窄程度的准确性。结果:经DSA诊断狭窄程度大于50%的共有305段血管,其中髂动脉段有63段,股腘动脉段有128段,经胫腓动脉段有114段;CTA和CE‐MRA对病变血管的定

  8. Peripheral pulmonary arteries: identification at multi-slice spiral CT with 3D reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Coche, Emmanuel; Pawlak, Sebastien; Dechambre, Stephane; Maldague, Baudouin [Department of Radiology, St. Luc Hospital, UCL, Avenue Hippocrate, 10, 1200 Brussels (Belgium)

    2003-04-01

    Our objective was to analyze the peripheral pulmonary arteries using thin-collimation multi-slice spiral CT. Twenty consecutive patients underwent enhanced-spiral multi-slice CT using 1-mm collimation. Two observers analyzed the pulmonary arteries by consensus on a workstation. Each artery was identified on axial and 3D shaded-surface display reconstruction images. Each subsegmental artery was measured at a mediastinal window setting and compared with anatomical classifications. The location and branching of every subsegmental artery was recorded. The number of well-visualized sub-subsegmental arteries at a mediastinal window setting was compared with those visualized at a lung window setting. Of 800 subsegmental arteries, 769 (96%) were correctly visualized and 123 accessory subsegmental arteries were identified using the mediastinal window setting. One thousand ninety-two of 2019 sub-subsegmental arteries (54%) identified using the lung window setting were correctly visualized using the mediastinal window setting. Enhanced multi-slice spiral CT with thin collimation can be used to analyze precisely the subsegmental pulmonary arteries and may identify even more distal pulmonary arteries. (orig.)

  9. Peripheral pulmonary arteries: identification at multi-slice spiral CT with 3D reconstruction.

    Science.gov (United States)

    Coche, Emmanuel; Pawlak, Sebastien; Dechambre, Stéphane; Maldague, Baudouin

    2003-04-01

    Our objective was to analyze the peripheral pulmonary arteries using thin-collimation multi-slice spiral CT. Twenty consecutive patients underwent enhanced-spiral multi-slice CT using 1-mm collimation. Two observers analyzed the pulmonary arteries by consensus on a workstation. Each artery was identified on axial and 3D shaded-surface display reconstruction images. Each subsegmental artery was measured at a mediastinal window setting and compared with anatomical classifications. The location and branching of every subsegmental artery was recorded. The number of well-visualized sub-subsegmental arteries at a mediastinal window setting was compared with those visualized at a lung window setting. Of 800 subsegmental arteries, 769 (96%) were correctly visualized and 123 accessory subsegmental arteries were identified using the mediastinal window setting. One thousand ninety-two of 2019 sub-subsegmental arteries (54%) identified using the lung window setting were correctly visualized using the mediastinal window setting. Enhanced multi-slice spiral CT with thin collimation can be used to analyze precisely the subsegmental pulmonary arteries and may identify even more distal pulmonary arteries.

  10. Cranial and caudal mesenteric arteries of the paca (Cuniculus paca, L. 1766

    Directory of Open Access Journals (Sweden)

    Isabela Cristina de Souza Marques

    2013-03-01

    Full Text Available The paca (Cuniculus paca, Linnaeus, 1766 is a medium-sized rodent that occurs in Brazil; however, there is little information regarding its morphology. The goal of this study was to describe the origin and branching of the cranial and caudal mesenteric arteries of this rodent in order to contribute to comparative anatomy studies. Ten animals (males and females were used. After death, their thoracic inlet was opened between the fourth and sixth ribs to expose the thoracic aorta, which was cannulated caudally. A stained, neoprene latex solution was then injected, in order to fill the arterial system, and the preparations were fixed in a 10% aqueous formalin solution for over 72h. The fixed specimens were dissected to identify the cranial and caudal mesenteric arteries. The cranial mesenteric artery started at the abdominal aorta, caudally to the celiac artery, and originated in the following arterial branches: caudal pancreatic duodenal, pancreatic, jejunal, ileum colic and cecal. The origin of the caudal mesenteric artery occurred next to the end of abdominal aorta and this vessel issued the left colic artery and cranial rectal artery from which the sigmoid arteries initiated. It was found that there was little difference in the branching pattern of the arteries compared to other rodents and domestic mammals.

  11. Countercurrent aortography via radial artery

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Hyung Kuk; Lee, Young Chun; Lee, Seung Chul; Jeon, Seok Chol; Joo, Kyung Bin; Lee, Seung Ro; Kim, Soon Yong [College of Medicine, Hanyang University, Seoul (Korea, Republic of)

    1987-06-15

    Countercurrent aortography via radial artery was performed for detection of aortic arch anomalies in 4 infants with congenital heart disease. Author's cases of aortic arch anomalies were 3 cases of PDA, 1 case of coarctation of aorta, and 1 case of occlusion of anastomosis site on subclavian artery B-T shunt. And aberrant origin of the right SCA, interrupted aortic arch, hypoplastic aorta, anomalous origin of the right pulmonary artery from the ascending aorta can be demonstrated by this method. Countercurrent aortography affords an safe and simple method for detection of aortic arch anomalies without retrograde arterial catheterization, especially in small infants or premature babies.

  12. Arterial Abnormalities Leading to Tinnitus.

    Science.gov (United States)

    Miller, Timothy R; Serulle, Yafell; Gandhi, Dheeraj

    2016-05-01

    Tinnitus is a common symptom that usually originates in the middle ear. Vascular causes of pulsatile tinnitus are categorized by the location of the source of the noise within the cerebral-cervical vasculature: arterial, arteriovenous, and venous. Arterial stenosis secondary to atherosclerotic disease or dissection, arterial anatomic variants at the skull base, and vascular skull base tumors are some of the more common causes of arterial and arteriovenous pulsatile tinnitus. Noninvasive imaging is indicated to evaluate for possible causes of pulsatile tinnitus, and should be followed by catheter angiography if there is a strong clinical suspicion for a dural arteriovenous fistula.

  13. Pulmonary arterial hypertension in pregnancy.

    Science.gov (United States)

    Običan, Sarah G; Cleary, Kirsten L

    2014-08-01

    Pulmonary hypertension is a medical condition characterized by elevated pulmonary arterial pressure and secondary right heart failure. Pulmonary arterial hypertension is a subset of pulmonary hypertension, which is characterized by an underlying disorder of the pulmonary arterial vasculature. Pulmonary hypertension can also occur secondarily to structural cardiac disease, autoimmune disorders, and toxic exposures. Although pregnancies affected by pulmonary hypertension and pulmonary arterial hypertension are rare, the pathophysiology exacerbated by pregnancy confers both high maternal and fetal mortality and morbidity. In light of new treatment modalities and the use of a multidisciplinary approach to care, maternal outcomes may be improving.

  14. Anesthetic Management of Pediatric Pulmonary Arterial Hypertension

    Directory of Open Access Journals (Sweden)

    Mediha Turktan

    2015-06-01

    Full Text Available Pulmonary arterial hypertension is the most important cause of morbidity and mortality associated with congenital heart disease. Patients in this group have a greater peroperative cardiovascular risks including cardiac arrest, pulmonary hypertensive crisis and death compared the normal population. The main purpose of anesthesia is to avoid increased pulmonary vascular resistance and myocardial depression. [Archives Medical Review Journal 2015; 24(2.000: 149-158

  15. Pulmonary arterial hypertension in children: diagnosis using ratio of main pulmonary artery to ascending aorta diameter as determined by multi-detector computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Caro-Dominguez, Pablo; Manson, David E. [University of Toronto, Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, Toronto, ON (Canada); Compton, Gregory [University of Toronto, Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, Toronto, ON (Canada); Epworth Hospital, Epworth Medical Imaging, Richmond, VIC (Australia); Humpl, Tilman [University of Toronto, Division of Cardiology, Department of Pediatrics, The Hospital for Sick Children, Toronto, ON (Canada)

    2016-09-15

    The ratio of the transverse diameter of the main pulmonary artery (MPA) to ascending aorta as determined at multi-detector CT is a tool that can be used to assess the pulmonary arterial size in cases of pulmonary arterial hypertension in children. To establish a ratio of MPA to ascending aorta diameter using multi-detector CT imaging suggestive of pulmonary arterial hypertension in children. We hypothesize that a defined ratio of MPA to ascending aorta is identifiable on multi-detector CT and that higher ratios can be used to reliably diagnose the presence of pulmonary arterial hypertension in children. We calculated the multi-detector CT ratio of MPA to ascending aorta diameter in 44 children with documented pulmonary arterial hypertension by right heart catheterization and in 44 age- and gender-matched control children with no predisposing factors for pulmonary arterial hypertension. We compared this multi-detector-CT-determined ratio with the MPA pressure in the study group, as well as with the ratio of MPA to ascending aorta in the control group. A threshold ratio value was calculated to accurately identify children with pulmonary arterial hypertension. Children with documented primary pulmonary arterial hypertension have a significantly higher ratio of MPA to ascending aorta (1.46) than children without pulmonary arterial hypertension (1.11). A ratio of 1.3 carries a positive likelihood of 34 and a positive predictive value of 97% for the diagnosis of pulmonary arterial hypertension. The pulmonary arteries were larger in children with pulmonary arterial hypertension than in a control group of normal children. A CT-measured ratio of MPA to ascending aorta of 1.3 should raise the suspicion of pulmonary arterial hypertension in children. (orig.)

  16. Anatomical variation of the origin of the left vertebral artery

    OpenAIRE

    Patasi B; Yeung A; Goodwin S; Jalali A

    2009-01-01

    This paper presents and describes the anatomical variation of the left vertebral artery originating from the arch of aorta as a case report. This variation was found in one of the cadavers at the Division of Clinical and Functional Anatomy, Faculty of Medicine, University of Ottawa. During routine dissection of a male cadaver, in the superior mediastinum and the neck we observed an atypical origin of the left vertebral artery. Atypical origin was compared to the typical origin of the left ver...

  17. HISTOLOGICAL STUDY OF MEDIUM SIZED ARTERIES OF NECK IN RELATION WITH THEIR PULSE PRESSURE AND PULSATORY POWER

    Directory of Open Access Journals (Sweden)

    Prerana

    2014-11-01

    Full Text Available : INTRODUCTION: There are several studies on the microstructure of main arteries of the body but limited have been dealt with the neck arteries. It has been mentioned that the vascular pathologies like the thrombo-embolism, atherosclerosis and infarction are common in the branches of vertebral and internal carotid artery as compared to the branches of external carotid artery. OBJECTIVE: To study the histological structure of the 3 medium sized arteries of neck namely external carotid, internal carotid and vertebral artery, calculation of their mean pulse pressure and pulsatory power and to find any association between them if present. METHOD: Fresh samples of external carotid, internal carotid and vertebral artery each measuring 10mm in length were taken from five cadavers and prepared for histological examination under microscope using orcein and H&E stain. The mean pressure and pulsatory power of these arteries were calculated by taking the measurements such as wall thickness, lumen circumference, arterial wall area, and smooth muscle fibre density in tunica media in that arterial segment. RESULT: The pulsatory power of external carotid artery, internal carotid artery and vertebral artery is found to be 120, 273.3, 400 Joules /heart beat and the mean pressure is 17.1 mm Hg, 27.3 mm Hg and 33.3 mm Hg respectively. CONCLUSION: The thickness of tunica media of an artery is directly proportional to its pulsatory power. The mean pulse pressure, pulsatory power as well the number of smooth muscles fibres in tunica media are more in internal carotid artery and vertebral artery in comparison to external carotid artery. It may be a very important reason why vascular pathologies are less common in branches of external carotid as compare to internal carotid and vertebral artery.

  18. [Measurement of arterial pressure].

    Science.gov (United States)

    Rorive, G

    1998-03-01

    The casual determination of blood pressure remains the basis of the diagnosis of arterial hypertension and the criteria for usefulness of drug therapy. The reference values usually in use concern determinations by the doctor in very well defined conditions, rest, size of the bladder, etc.... The poor reproductibility of the determinations made by the doctor in casual conditions has produced a large interest for new approaches: autodetermination by the patient at home, and ambulatory blood pressure determinations using automatic devices. These new approaches have their own reference values, specific indications and limitations.

  19. Dual anterior descending coronary artery associated with coronary artery disease

    Directory of Open Access Journals (Sweden)

    Siqueira Luciane da L. V.

    2003-01-01

    Full Text Available The patient is a male with risk factors for coronary artery disease, who was referred for cardiac catheterization after acute myocardial infarction in the inferior wall. The patient underwent transluminal coronary angioplasty in the right coronary artery with successful stent implantation.

  20. Finite Element Calculation of the Flexural Stiffness of Corroded RC Eccentric Compressive Members

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hua; WEI Jun; PAN Qiao; HUANG Ying

    2010-01-01

    A finite element calculation model of corroded RC eccentric compressive members was build using finite element software ANSYS. The model considers the decline of mechanical properties and the effective section of a corroded steel bar, as well as the deterioration of bond character between corroded reinforcement and concrete. The reliability of the finite element model was evaluated by comparing the results of the finite element calculation with the data from experiments. Based on the finite element analysis results, the influence of corrosion degree, the diameter change of the longitudinal reinforcing bars and the spacing change of stirrups on the flexural stiffness were calculated and analyzed.

  1. Presence of anomalous coronary seen on angiogram is not associated with increased risk of significant coronary artery disease.

    Science.gov (United States)

    Suryanarayana, Prakash; Kollampare, Shubha; Riaz, Irbaz Bin; Lee, Justin; Husnain, Muhammad; Luni, Faraz Khan; Movahed, Mohammad Reza

    2014-12-01

    It is unclear if anomalous coronary arteries are at higher risk for atherosclerosis. The link between anomalous coronary artery and early coronary artery disease has been suggested. The aim of this study is to determine whether the coronary artery anomaly predisposes to development of significant coronary disease. Using retrospective chart review, patients with documented anomalous coronary arteries recognized during coronary angiography between years 2000 to 2007 were analyzed. Prevalence of significant atherosclerotic coronary artery disease (defined as more than 50% luminal narrowing) was compared between normal and anomalous coronaries. A total of 147 patients with anomalous coronary arteries were found. Right coronary artery was the most common anomalous artery 128 of 148 (86.5%) in our dataset. There was no difference in the occurrence of atherosclerosis between anomalous and nonanomalous coronaries. Significant atherosclerosis was present in 59 of the 148 anomalous coronary arteries (37.8%), and 112 of the 293 nonanomalous coronary arteries (38.2%, p = 0.9). On the basis of our study, there is no evidence that anomalous coronary arteries predispose to significant coronary artery disease in comparison to normal coronary arteries.

  2. Endovascular nonthermal irreversible electroporation: a finite element analysis.

    Science.gov (United States)

    Maor, Elad; Rubinsky, Boris

    2010-03-01

    Tissue ablation finds an increasing use in modern medicine. Nonthermal irreversible electroporation (NTIRE) is a biophysical phenomenon and an emerging novel tissue ablation modality, in which electric fields are applied in a pulsed mode to produce nanoscale defects to the cell membrane phospholipid bilayer, in such a way that Joule heating is minimized and thermal damage to other molecules in the treated volume is reduced while the cells die. Here we present a two-dimensional transient finite element model to simulate the electric field and thermal damage to the arterial wall due to an endovascular NTIRE novel device. The electric field was used to calculate the Joule heating effect, and a transient solution of the temperature is presented using the Pennes bioheat equation. This is followed by a kinetic model of the thermal damage based on the Arrhenius formulation and calculation of the Henriques and Moritz thermal damage integral. The analysis shows that the endovascular application of 90, 100 mus pulses with a potential difference of 600 V can induce electric fields of 1000 V/cm and above across the entire arterial wall, which are sufficient for irreversible electroporation. The temperature in the arterial wall reached a maximum of 66.7 degrees C with a pulse frequency of 4 Hz. Thermal damage integral showed that this protocol will thermally damage less than 2% of the molecules around the electrodes. In conclusion, endovascular NTIRE is possible. Our study sets the theoretical basis for further preclinical and clinical trials with endovascular NTIRE.

  3. Chiral interpolation in a finite volume

    CERN Document Server

    Fukaya, H; Hashimoto, S; Kaneko, T; Matsufuru, H; Noaki, J; Onogi, T; Yamada, N

    2011-01-01

    A simulation of lattice QCD at (or even below) the physical pion mass is feasible on a small lattice size of \\sim 2 fm. The results are, however, subject to large finite volume effects. In order to precisely understand the chiral behavior in a finite volume, we develop a new computational scheme to interpolate the conventional epsilon and p regimes within chiral perturbation theory. In this new scheme, we calculate the two-point function in the pseudoscalar channel, which is described by a set of Bessel functions in an infra-red finite way as in the epsilon regime, while chiral logarithmic effects are kept manifest as in the p regime. The new ChPT formula is compared to our 2+1- flavor lattice QCD data near the physical up and down quark mass, mud \\sim 3 MeV on an L \\sim 1.8 fm lattice. We extract the pion mass = 99(4) MeV, from which we attempt a chiral "interpolation" of the observables to the physical point.

  4. Genetics Home Reference: pulmonary arterial hypertension

    Science.gov (United States)

    ... Home Health Conditions pulmonary arterial hypertension pulmonary arterial hypertension Enable Javascript to view the expand/collapse boxes. ... PDF Open All Close All Description Pulmonary arterial hypertension is a progressive disorder characterized by abnormally high ...

  5. Patient-Specific Simulation of Coronary Artery Pressure Measurements: An In Vivo Three-Dimensional Validation Study in Humans

    Directory of Open Access Journals (Sweden)

    Panagiotis K. Siogkas

    2015-01-01

    Full Text Available Pressure measurements using finite element computations without the need of a wire could be valuable in clinical practice. Our aim was to compare the computed distal coronary pressure values with the measured values using a pressure wire, while testing the effect of different boundary conditions for the simulation. Eight coronary arteries (lumen and outer vessel wall from six patients were reconstructed in three-dimensional (3D space using intravascular ultrasound and biplane angiographic images. Pressure values at the distal and proximal end of the vessel and flow velocity values at the distal end were acquired with the use of a combo pressure-flow wire. The 3D lumen and wall models were discretized into finite elements; fluid structure interaction (FSI and rigid wall simulations were performed for one cardiac cycle both with pulsatile and steady flow in separate simulations. The results showed a high correlation between the measured and the computed coronary pressure values (coefficient of determination [r2] ranging between 0.8902 and 0.9961, while the less demanding simulations using steady flow and rigid walls resulted in very small relative error. Our study demonstrates that computational assessment of coronary pressure is feasible and seems to be accurate compared to the wire-based measurements.

  6. Different radiation impedance models for finite porous materials

    DEFF Research Database (Denmark)

    Nolan, Melanie; Jeong, Cheol-Ho; Brunskog, Jonas;

    2015-01-01

    coupled to the transfer matrix method (TMM). These methods are found to yield comparable results when predicting the Sabine absorption coefficients of finite porous materials. Discrepancies with measurement results can essentially be explained by the unbalance between grazing and non-grazing sound field...... the infinite case. Thus, in order to predict the Sabine absorption coefficients of finite porous samples, one can incorporate models of the radiation impedance. In this study, different radiation impedance models are compared with two experimental examples. Thomasson’s model is compared to Rhazi’s method when...

  7. Cadaveric study: study of lateral circumflex femoral arterial origin in Rajkot

    Directory of Open Access Journals (Sweden)

    Pradip Rameshbhai Chauhan

    2015-05-01

    Full Text Available Background: Lateral circumflex femoral artery contributes cruciate, trochanteric and knee joint anastomosis. In addition Lateral circumflex femoral artery flaps are used for the reconstruction of large tissue loss in the head and neck region, aortopopliteal bypass, coronary artery bypass grafting and extracranial intracranial bypass surgery. This work was carried out (a to study the origin of lateral circumflex femoral artery and (b to measure and compare (between male and female the circumference at its origin. Methods: In this cross sectional study, 51 femoral triangles from 26 (18 male and 08 female human adult cadavers were dissected and studied at P.D.U. government medical college, Rajkot, Gujarat. Site of origin of lateral circumflex femoral artery was identified and noted. The distance of origin of the artery from the origin of profunda femoris artery was measured and noted. Circumference at the level of origin was measured and diameter was calculated. Collected data was analysed by standard statistical formulas with the help of Microsoft excel 2013 and Epi info 7TM software. Results: 90.19% lateral circumflex femoral arteries originated from the profunda femoris artery and remaining 9.81% from the femoral artery. The mean distance of origin of the artery from the origin of profunda femoris artery was 18.44 mm. Lateral circumflex femoral artery circumference and diameter were significantly different between male and female (95% confidence interval, P <0.05. Conclusion: In this presented study maximum distance of origin of the artery from the origin was 65 mm while minimum distance of origin was 6 mm. In addition difference in circumference of the artery was statistically significant. [Int J Res Med Sci 2015; 3(5.000: 1066-1069

  8. Anisotropic micro-sphere-based finite elasticity applied to blood vessel modelling

    Science.gov (United States)

    Alastrué, V.; Martínez, M. A.; Doblaré, M.; Menzel, A.

    2009-01-01

    A fully three-dimensional anisotropic elastic model for vascular tissue modelling is presented here. The underlying strain energy density function is assumed to additively decouple into volumetric and deviatoric contributions. A straightforward isotropic neo-Hooke-type law is used to model the deviatoric response of the ground substance, whereas a micro-structurally or rather micro-sphere-based approach will be employed to model the contribution and distribution of fibres within the biological tissue of interest. Anisotropy was introduced by means of the use of von Mises orientation distribution functions. Two different micro-mechanical approaches—a, say phenomenological, exponential ansatz, and a worm-like-chain-based formulation—are applied to the micro-fibres and illustratively compared. The passage from micro-structural contributions to the macroscopic response is obtained by a computational homogenisation scheme, namely numerical integration over the surface of the individual micro-spheres. The algorithmic treatment of this integration is discussed in detail for the anisotropic problem at hand, so that several cubatures of the micro-sphere are tested in order to optimise the accuracy at reasonable computational cost. Moreover, the introduced material parameters are identified from simple tension tests on human coronary arterial tissue for the two micro-mechanical models investigated. Both approaches are able to recapture the experimental data. Based on the identified sets of parameters, we first discuss a homogeneous deformation in simple shear to evaluate the models' response at the micro-structural level. Later on, an artery-like two-layered tube subjected to internal pressure is simulated by making use of a non-linear finite element setting. This enables to obtain the micro- and macroscopic responses in an inhomogeneous deformation problem, namely a blood vessel representative boundary value problem. The effect of residual stresses is additionally

  9. Infinite to finite: An overview of finite element analysis

    Directory of Open Access Journals (Sweden)

    Srirekha A

    2010-01-01

    Full Text Available The method of finite elements was developed at perfectly right times; growing computer capacities, growing human skills and industry demands for ever faster and cost effective product development providing unlimited possibilities for the researching community. This paper reviews the basic concept, current status, advances, advantages, limitations and applications of finite element method (FEM in restorative dentistry and endodontics. Finite element method is able to reveal the otherwise inaccessible stress distribution within the tooth-restoration complex and it has proven to be a useful tool in the thinking process for the understanding of tooth biomechanics and the biomimetic approach in restorative dentistry. Further improvement of the non-linear FEM solutions should be encouraged to widen the range of applications in dental and oral health science.

  10. Isolated superior mesenteric artery dissection

    Directory of Open Access Journals (Sweden)

    Lalitha Palle

    2010-01-01

    Full Text Available Isolated superior mesenteric artery (SMA dissection without involvement of the aorta and the SMA origin is unusual. We present a case of an elderly gentleman who had chronic abdominal pain, worse after meals. CT angiography, performed on a 64-slice CT scanner, revealed SMA dissection with a thrombus. A large artery of Drummond was also seen. The patient was managed conservatively.

  11. Epigenetics and Peripheral Artery Disease.

    Science.gov (United States)

    Golledge, Jonathan; Biros, Erik; Bingley, John; Iyer, Vikram; Krishna, Smriti M

    2016-04-01

    The term epigenetics is usually used to describe inheritable changes in gene function which do not involve changes in the DNA sequence. These typically include non-coding RNAs, DNA methylation and histone modifications. Smoking and older age are recognised risk factors for peripheral artery diseases, such as occlusive lower limb artery disease and abdominal aortic aneurysm, and have been implicated in promoting epigenetic changes. This brief review describes studies that have associated epigenetic factors with peripheral artery diseases and investigations which have examined the effect of epigenetic modifications on the outcome of peripheral artery diseases in mouse models. Investigations have largely focused on microRNAs and have identified a number of circulating microRNAs associated with human peripheral artery diseases. Upregulating or antagonising a number of microRNAs has also been reported to limit aortic aneurysm development and hind limb ischemia in mouse models. The importance of DNA methylation and histone modifications in peripheral artery disease has been relatively little studied. Whether circulating microRNAs can be used to assist identification of patients with peripheral artery diseases and be modified in order to improve the outcome of peripheral artery disease will require further investigation.

  12. Pulmonary arterial hypertension : an update

    NARCIS (Netherlands)

    Hoendermis, E. S.

    2011-01-01

    Pulmonary arterial hypertension (PAH), defined as group 1 of the World Heart Organisation (WHO) classification of pulmonary hypertension, is an uncommon disorder of the pulmonary vascular system. It is characterised by an increased pulmonary artery pressure, increased pulmonary vascular resistance a

  13. 对比增强血管造影双期扫描在头颈部血管狭窄的临床应用%Comparative analyses of dual-phase contrast-enhanced MR angiography (CE-MRA) in the clinical application of head and ca-rotid artery stenosis

    Institute of Scientific and Technical Information of China (English)

    韦寅; 陈鹏; 谭璨; 李燕华; 严健明

    2015-01-01

    Objective To explore the application of dual‐phase 3D CE‐MRA in head and carotid artery stenosis .Methods The dual‐phase 3D CE‐MRA and digital subtraction angiography (DSA) were performed in 51 cases suspected with head and carotid artery stenosis .We made a correlated comparison concerning the diagnostic results of arterial‐phase 3D CE‐MRA ,dual‐phase 3D CE‐MRA and DSA .Results Compared with the results of DSA ,which was regarded as the “gold standard” ,the sensitivity ,specificity ,positive predictive values ,negative predictive values and the total corresponding rate of arterial‐phase and dual‐phase 3D CE‐MRA in head and carotid artery stenosis were 90 .81% and 90 .81% ,92 .96%and 95 .62% ,98 .09% and 98 .14% ,71 .79% and 80 .38% ,92 .6% and 94 .83% ,respectively .The consistent rates in di‐agnosis on mid‐stenosis ,moderate‐stenosis ,severe‐stenosis and complete occlusion were 81 .10% and 89 .86% ;60 .65%and 74 .07% ;91 .30% and 95 .45% ;78 .58% and 91 .67% .Conclusion Compared with the arterial‐phase 3D CE‐MRA , the dual‐phase 3D CE‐MRA is less time‐consuming .It results in fewer doses of the contrast media ,reducing patience’s cost ,but providing more accurate diagnosis .The dual‐phase 3D CE‐MRA has particular advantage and will be a safe ,non‐invasive ,reliable and new examination in diagnosis of head and carotid artery stenosis .%目的:探讨一次增强完成头颈部双期扫描在头颈部血管狭窄中的应用价值。方法对51例可疑头颈部动脉狭窄的患者分别行3D CE‐M RA双期和DSA检查,对成像结果进行相关性比较。结果与DSA相比,3D CE‐M RA动脉期及3D CE‐M RA双期诊断头颈部动脉狭窄灵敏度、特异度、阳性预测值、阴性预测值、总符合率分别为90.81%和90.81%、92.96%和95.62%、71.79%和80.38%、98.09%和98.14%、92.6%和94.83%;诊断头颈部动脉轻度、中度、重度狭窄、

  14. Geometrical Underpinning of Finite Dimensional Hilbert space

    CERN Document Server

    Revzen, M

    2011-01-01

    Finite geometry is employed to underpin operators in finite, d, dimensional Hilbert space. The central role of Hilbert space operators that form mutual unbiased bases (MUB) states projectors is exhibited. Interrelation among them revealed through their (finite) dual affine plane geometry (DAPG) underpinning is studied. Transcription to (finite) affine plane geometry (APG) is given and utilized for their interpretation.

  15. Geometrical Underpinning of Finite Dimensional Hilbert space

    OpenAIRE

    Revzen, M.

    2011-01-01

    Finite geometry is employed to underpin operators in finite, d, dimensional Hilbert space. The central role of mutual unbiased bases (MUB) states projectors is exhibited. Interrelation among operators in Hilbert space, revealed through their (finite) dual affine plane geometry (DAPG) underpinning is studied. Transcription to (finite) affine plane geometry (APG) is given and utilized for their interpretation.

  16. A Finite Speed Curzon-Ahlborn Engine

    Science.gov (United States)

    Agrawal, D. C.

    2009-01-01

    Curzon and Ahlborn achieved finite power output by introducing the concept of finite rate of heat transfer in a Carnot engine. The finite power can also be achieved through a finite speed of the piston on the four branches of the Carnot cycle. The present paper combines these two approaches to study the behaviour of output power in terms of…

  17. Comparison Study on the Performances of Finite Volume Method and Finite Difference Method

    Directory of Open Access Journals (Sweden)

    Renwei Liu

    2013-01-01

    Full Text Available Vorticity-stream function method and MAC algorithm are adopted to systemically compare the finite volume method (FVM and finite difference method (FDM in this paper. Two typical problems—lid-driven flow and natural convection flow in a square cavity—are taken as examples to compare and analyze the calculation performances of FVM and FDM with variant mesh densities, discrete forms, and treatments of boundary condition. It is indicated that FVM is superior to FDM from the perspective of accuracy, stability of convection term, robustness, and calculation efficiency. Particularly ,when the mesh is coarse and taken as 20×20, the results of FDM suffer severe oscillation and even lose physical meaning.

  18. Arterial Stiffness: Recommendations and Standardization

    Science.gov (United States)

    Townsend, Raymond R.

    2017-01-01

    The use of arterial stiffness measurements in longitudinal cohorts of normal populations, hypertensive patients, diabetic patients, healthy elderly, and patients on hemodialysis have confirmed the value of this important measure of arterial health, and established its complementary role to measures of blood pressure. Its contribution to understanding cardiovascular and mortality risk beyond blood pressure measurements has moved measures of arterial stiffness into the ranks of factors such as elevated cholesterol, diabetes, and left ventricular hypertrophy in considering cardiovascular risk. The recent international collaboration's publication of reference ranges for normal people and those with hypertension, along with the American Heart Association's recent scientific statement on standardizing arterial stiffness measurements are important aspects to consider in future studies employing these valuable methods, particularly as interventions that not only lower blood pressure but improve arterial function are tested in the clinical arena. PMID:28275588

  19. Liver cirrhosis and arterial hypertension

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik; Møller, Søren

    2006-01-01

    blood pressure. This review considers the alterations in systemic hemodynamics in patients with cirrhosis in relation to essential hypertension and arterial hypertension of the renal origin. Subjects with arterial hypertension (essential, secondary) may become normotensive during the development...... of cirrhosis, and arterial hypertension is rarely manifested in patients with cirrhosis, even in cases with renovascular disease and high circulating renin activity. There is much dispute as to the understanding of homoeostatic regulation in cirrhotic patients with manifest arterial hypertension. This most......Characteristic findings in patients with cirrhosis are vasodilatation with low overall systemic vascular resistance, high arterial compliance, increased cardiac output, secondary activation of counter-regulatory systems (renin-angiotensin-aldosterone system, sympathetic nervous system, release...

  20. Liver cirrhosis and arterial hypertension

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik; Møller, Søren

    2006-01-01

    blood pressure. This review considers the alterations in systemic hemodynamics in patients with cirrhosis in relation to essential hypertension and arterial hypertension of the renal origin. Subjects with arterial hypertension (essential, secondary) may become normotensive during the development...... of cirrhosis, and arterial hypertension is rarely manifested in patients with cirrhosis, even in cases with renovascular disease and high circulating renin activity. There is much dispute as to the understanding of homoeostatic regulation in cirrhotic patients with manifest arterial hypertension. This most...... likely includes the combination of vasodilatation and vasoconstriction in parallel. Arterial compliance; Central vascular filling; Chyperdynamic circulation; Kidney function, Nitric oxide; Blood pressure regulation; Renin–angiotensin–aldosterone system; Sympathetic nervous system; Vasodilatation...

  1. Combinatorial Properties of Finite Models

    Science.gov (United States)

    Hubicka, Jan

    2010-09-01

    We study countable embedding-universal and homomorphism-universal structures and unify results related to both of these notions. We show that many universal and ultrahomogeneous structures allow a concise description (called here a finite presentation). Extending classical work of Rado (for the random graph), we find a finite presentation for each of the following classes: homogeneous undirected graphs, homogeneous tournaments and homogeneous partially ordered sets. We also give a finite presentation of the rational Urysohn metric space and some homogeneous directed graphs. We survey well known structures that are finitely presented. We focus on structures endowed with natural partial orders and prove their universality. These partial orders include partial orders on sets of words, partial orders formed by geometric objects, grammars, polynomials and homomorphism orders for various combinatorial objects. We give a new combinatorial proof of the existence of embedding-universal objects for homomorphism-defined classes of structures. This relates countable embedding-universal structures to homomorphism dualities (finite homomorphism-universal structures) and Urysohn metric spaces. Our explicit construction also allows us to show several properties of these structures.

  2. A prospective multicenter parallel-controlled trial of TIVOLI biodegradable-polymer-based sirolimus-eluting stent compared to ENDEAVOR zotarolimus-eluting stent for the treatment of coronary artery disease: 8-month angiographic and 2-year clinical follow-up results

    Institute of Scientific and Technical Information of China (English)

    XU Bo; LI Wei-min; CHEN Ji-yan; WANG Lei; WANG Yong; GE Jun-bo; LI Wei; GAO Run-lin; DOU Ke-fei; HAN Ya-ling; L(U) Shu-zheng; YANG Yue-jin; HUO Yong; WANG Le-feng; CHEN Yun-dai; WANG Hai-chang

    2011-01-01

    Background Available drug-eluting stents (DES) have achieved great success in reducing restenosis rates. Recently,investigators have demonstrated that the durable polymer carrier plays a significant role in DES-related hypersensitive reaction and delays vessel healing. TIVOLI stent is a novel sirolimus-eluting coronary stent with biodegradable coating containing sirolimus and polylactic-co-glycolic acid (PLGA) polymer. The present study sought to evaluate the effectiveness and safety of the TIVOLI biodegradable-polymer-based sirolimus-eluting stent in treating patients with coronary artery disease.Methods A prospective, multicenter clinical trial comparing TIVOLI biodegradable coated sirolimus-eluting stent with ENDEAVOR zotarolimus-eluting stent was conducted in 324 patients (TIVOLI group: 168 patients; ENDEAVOR group:156 patients) at 12 centers in China to demonstrate the non-inferiority of in-stent late loss with TIVOLI stent compared to ENDEAVOR stent in subjects with a maximum of two de novo native coronary artery lesions (lesion length ≤40 mm,reference vessel diameter 2.25-4.00 mm). The primary end point was angiographic in-stent late loss at 8-month. The secondary end points were clinical outcomes at 2 years,including major adverse cardiac events (cardiac death,myocardial infarction, or target-lesion revascularization) and stent thrombosis.Results Angiographic late lumen loss at 8 months in the TIVOLI group was superior to the ENDEAVOR group (in-stent (0.25±0.33) mm vs. (0.57±0.55) mm, diff (95% CI)-0.23 (-0.32, -0.14), P <0.0001; in-segment (0.25±-0.33) mm vs. (0.42±-0.55) mm, diff (95% CI) -0.13 (-0.23, -0.02),P=0.0083). The rate of in-stent binary restenosis at 8 months was reduced from 8.6% in the ENDEAVOR group to 2.9% in the TIVOLI group (P=0.0229). Compared to ENDEAVOR stent, TIVOLI stent resulted in a significant reduction in target-lesion revascularization (4.2% vs. 9.6%, P=0.0495) at 2 years. The two-year major adverse cardiac events (MACE

  3. Differential effects of relaxin deficiency on vascular aging in arteries of male mice.

    Science.gov (United States)

    Jelinic, Maria; Tare, Marianne; Conrad, Kirk P; Parry, Laura J

    2015-08-01

    Exogenous treatment with the naturally occurring peptide relaxin increases arterial compliance and reduces vascular stiffness. In contrast, relaxin deficiency reduces the passive compliance of small renal arteries through geometric and compositional vascular remodeling. The role of endogenous relaxin on passive mechanical wall properties in other vascular beds is unknown. Importantly, no studies have investigated the effects of aging in arteries of relaxin-deficient mice. Therefore, we tested the hypothesis that mesenteric and femoral arteries stiffen with aging, and this is exacerbated with relaxin deficiency. Male wild-type (Rln (+/+)) and relaxin knockout (Rln (-/-)) mice were aged to 3, 6, 12, 18, and 23 months. Passive mechanical wall properties were assessed by pressure myography. In both genotypes, there was a significant increase in circumferential stiffening in mesenteric arteries with aging, whereas in the femoral artery, aging reduced volume compliance. This was associated with a reduced ability of the artery to lengthen with aging. The predominant phenotype observed in Rln (-/-) mice was reduced volume compliance in young mice in both mesenteric and femoral arteries. In summary, aging induces circumferential stiffening in mesenteric arteries and axial stiffening in femoral arteries. Passive mechanical wall properties of Rln (-/-) mouse arteries predominantly differ at younger ages compared with Rln (+/+) mice, suggesting that a lack of endogenous relaxin only has a minor effect on vascular aging.

  4. [Architectonics of gastric arterial bed in norm, after Nissen fundoplication, and its different combination with splenectomy and left gastric artery ligation].

    Science.gov (United States)

    Alekseyev, V S; Gaivoronskiy, I V; Kotiv, B N; Kuz'min, A A; Nichiporuk, G I

    2014-01-01

    A comparative study of the effect of the combination of Nissen fundoplication, different variants of splenectomy ligation of left gastric artery on stomach wall arterial bed blood fillability was carried out on 40 human corpses in 6 research series. The red lead paint suspension was used for the injection of arterial bed. It was shown that combination of Nissen operation andligation of stomach short arteries during splenectomy and left gastric artery trunk in its intraligamental part resulted in the impairment of the stomach wall blood supply. In the gastric fundus area avascular zones measuring from 2.5 x 3.0 to 5.0 x 10.0 cm and larger, were detected. The stomach wall of the given areas is potentially prone to necrosis. Avascular zones in the stomach wall were not observed when short gastric arteries were preserved.

  5. Revascularisation versus medical treatment in patients with stable coronary artery disease

    DEFF Research Database (Denmark)

    Windecker, Stephan; Stortecky, Stefan; Stefanini, Giulio G;

    2014-01-01

    OBJECTIVE: To investigate whether revascularisation improves prognosis compared with medical treatment among patients with stable coronary artery disease. DESIGN: Bayesian network meta-analyses to combine direct within trial comparisons between treatments with indirect evidence from other trials...... stent, early generation paclitaxel eluting stent, sirolimus eluting stent, and zotarolimus eluting (Endeavor) stent, and new generation everolimus eluting stent, and zotarolimus eluting (Resolute) stent among patients with stable coronary artery disease. DATA SOURCES: Medline and Embase from 1980......: Among patients with stable coronary artery disease, coronary artery bypass grafting reduces the risk of death, myocardial infarction, and subsequent revascularisation compared with medical treatment. All stent based coronary revascularisation technologies reduce the need for revascularisation...

  6. Fatal dissection of the pulmonary artery in pulmonary arterial hypertension

    Directory of Open Access Journals (Sweden)

    B. Degano

    2009-09-01

    Full Text Available A 41-yr-old patient with chronic stable idiopathic pulmonary arterial hypertension (PAH presented with sudden chest pain and unusual dyspnoea during physical exertion. The patient had been diagnosed with PAH at the age of 12 yrs and was in New York Heart Association functional class I/II. The patient was being treated with an anticoagulant regimen, low-dose diuretics and continuous intravenous epoprostenol therapy. A computed tomography scan showed ancient massive thrombi in dilated central pulmonary arteries, which were not haemodynamically significant (perfusion lung scans did not demonstrate segmental or larger defects, and extensive dissection of the right pulmonary artery starting from the intermediate branch. Due to the extensiveness of the dissection, the patient was immediately considered for heart–lung transplantation, but died 72 h after the onset of symptoms. Permission for post mortem examination was denied. Pulmonary artery dissection should be suspected in PAH patients presenting with chest pain and worsening dyspnoea. In the current case, the factors possibly associated with increased risk for dissection may include dilatation of the pulmonary artery, local inflammation favoured by in situ thrombosis, and acute increase of pulmonary pressure secondary to physical exertion. Extensive pulmonary artery dissection is a life-threatening complication of PAH, and urgent heart/lung transplantation might be the treatment of choice in eligible patients. In addition, better identification of the risk factors for pulmonary artery dissection may help in considering transplantation for selected patients at risk.

  7. MR manifestations of vertebral artery injuries in cervical spine trauma

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jeong Sik; Chung, Tae Sub; Kim, Young Soo; Cho, Yong Eun; Kang, Byung Chul; Kim, Dong Ik [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

    1996-11-01

    To assess the diagnostic efficacy of magnetic resonance (MR) imaging in the detection of a vertebral artery injury occurring from major cervical spine trauma. Conventional MR findings of 63 patients and 63 control subjects were compared to detect a possible change in the vertebral arteries resulted from trauma. Plain films, CT and clinical records were also reviewed to correlate the degree of cervical spine injury with vascular change. Nine cases of absent flow signals in vessel lumen were observed in eight patients and one was observed in the control group. Patients more frequently demonstrated other abnormalities such as intraluminal linear signals (n=3) or focal luminal narrowing (n=9) but there was no statistical significance. There was a close relationship between degree of cord damage and occlusion of the vertebral artery. Conventional MR imaging is useful in the detection of vertebral artery occlusion resulting from cervical spine trauma.

  8. Finiteness conditions for unions of semigroups

    OpenAIRE

    Abu-Ghazalh, Nabilah Hani

    2013-01-01

    In this thesis we prove the following: The semigroup which is a disjoint union of two or three copies of a group is a Clifford semigroup, Rees matrix semigroup or a combination between a Rees matrix semigroup and a group. Furthermore, the semigroup which is a disjoint union of finitely many copies of a finitely presented (residually finite) group is finitely presented (residually finite) semigroup. The constructions of the semigroup which is a disjoint union of two copies of the f...

  9. Radon Transform in Finite Dimensional Hilbert Space

    OpenAIRE

    Revzen, M.

    2012-01-01

    Novel analysis of finite dimensional Hilbert space is outlined. The approach bypasses general, inherent, difficulties present in handling angular variables in finite dimensional problems: The finite dimensional, d, Hilbert space operators are underpinned with finite geometry which provide intuitive perspective to the physical operators. The analysis emphasizes a central role for projectors of mutual unbiased bases (MUB) states, extending thereby their use in finite dimensional quantum mechani...

  10. Superrosy dependent groups having finitely satisfiable generics

    CERN Document Server

    Ealy, Clifton; Pillay, Anand

    2007-01-01

    We study a model theoretic context (finite thorn rank, NIP, with finitely satisfiable generics) which is a common generalization of groups of finite Morley rank and definably compact groups in o-minimal structures. We show that assuming thorn rank 1, the group is abelian-by-finite, and assuming thorn rank 2 the group is solvable by finite. Also a field is algebraically closed.

  11. Relationship of cerebral arterial stenosis to cognitive and memory disorders

    Institute of Scientific and Technical Information of China (English)

    Jifeng Li; Zhou Wang; Shenggang Sun; Gaomei Cai; Kejin Gu; Yaoqun Li

    2006-01-01

    BACKGROUND: Cerebral arterial stenosis can cause cerebral hypoperfusion, and than result in the decline of cognitive function, whereas the cognitive dysfunction induced by different cerebral arterial stenosis have different manifestations and types.OBJECTIVE: To observe the differences of cognitive and memory dysfunctions in patients with cerebral arterial stenosis of different types.DESIGN: A comparative observation.SETTING: Affiliated Hospital of Jining Medical College.PARTICIPANTS: Forty-two outpatients or inpatients with cerebral arterial stenosis were selected from the Department of Neurology, Affiliated Hospital of Jining Medical College from February 2005 to January 2006,including 25 males and 17 females. There were 18 cases of internal carotid arterial stenosis, 14 cases of vertebrobasilar arterial stenosis and 10 cases of whole cerebral arterial stenosis. The diagnostic standards for cerebral arterial stenosis were identified according to North American Symptomatic Carotid Endarterectomy Trial (NAS CET). Meanwhile, 18 healthy physical examinees were enrolled as the control group, including 10males and 8 females, aged 58-80 years old. All the enrolled subjects were informed and agreed with the detection and evaluation.METHODS: ① The memory function was evaluated using revised Wechsler memory scale for adults, including long-term memory (experience, orientation and counting), short-term memory (visual recognition, picture memory, visual regeneration, association and thigmesthesia) and sensory memory (forward and backward recitation of numbers). The scale scores were turned to memory quotients. The higher the scores, the better the memory function. ② The cognitive function was evaluated using revised Wechsler adult intelligence scale:It consisted of eleven subtests, including six language scales (information, digit span, vocabulary, arithmetics,apprehension, similarity) and five operation scales (picture completion, picture arrangement, block design

  12. Finite element methods for engineers

    CERN Document Server

    Fenner, Roger T

    2013-01-01

    This book is intended as a textbook providing a deliberately simple introduction to finite element methods in a way that should be readily understandable to engineers, both students and practising professionals. Only the very simplest elements are considered, mainly two dimensional three-noded “constant strain triangles”, with simple linear variation of the relevant variables. Chapters of the book deal with structural problems (beams), classification of a broad range of engineering into harmonic and biharmonic types, finite element analysis of harmonic problems, and finite element analysis of biharmonic problems (plane stress and plane strain). Full Fortran programs are listed and explained in detail, and a range of practical problems solved in the text. Despite being somewhat unfashionable for general programming purposes, the Fortran language remains very widely used in engineering. The programs listed, which were originally developed for use on mainframe computers, have been thoroughly updated for use ...

  13. Local density approximations from finite systems

    CERN Document Server

    Entwistle, Mike; Wetherell, Jack; Longstaff, Bradley; Ramsden, James; Godby, Rex

    2016-01-01

    The local density approximation (LDA) constructed through quantum Monte Carlo calculations of the homogeneous electron gas (HEG) is the most common approximation to the exchange-correlation functional in density functional theory. We introduce an alternative set of LDAs constructed from slab-like systems of one, two and three electrons that resemble the HEG within a finite region, and illustrate the concept in one dimension. Comparing with the exact densities and Kohn-Sham potentials for various test systems, we find that the LDAs give a good account of the self-interaction correction, but are less reliable when correlation is stronger or currents flow.

  14. [Grafting of carotid arteries].

    Science.gov (United States)

    Belov, Iu V; Stepanenko, A B; Gens, A P; Bazylev, V V; Seleznev, M N; Savichev, D D

    2005-01-01

    Over 5-years, 167 reconstructive surgeries for stenosis of internal carotid arteries (ICA) were performed in 124 patients. Mean age of the patients was 63.5 years. One hundred and twenty-nine carotid endarterectomies (CEAE) in 86 patients and 38 reconstructive operations of ICA in 38 patients were performed. There were no lethal outcomes in short- and long-term postoperative period. In short-term period after prosthesis of ICA restenosis was revealed in 3% patients, after eversion CEAE in 3% patients the embolism was seen, after standard CEAE restenosis were diagnosed in 8% patients and thrombosis -- in 3%. In long-term period after grafting of ICA the strokes were seen in 3%, stenosis -- in 6% patients, after eversion endarterectomy -- in 0 and 3% patients, and after standard CEAE -- in 3 and 24% patients, respectively. It is concluded that grafting of ICA is adequate surgical method of reconstruction and stroke prevention in specific variants of carotid atherosclerosis.

  15. Spontaneous Coronary Artery Dissection.

    Science.gov (United States)

    Tweet, Marysia S; Gulati, Rajiv; Hayes, Sharonne N

    2016-07-01

    Spontaneous coronary artery dissection is an important etiology of nonatherosclerotic acute coronary syndrome, myocardial infarction, and sudden death. Innovations in the catheterization laboratory including optical coherence tomography and intravascular ultrasound have enhanced the ability to visualize intimal disruption and intramural hematoma associated with SCAD. Formerly considered "rare," these technological advances and heightened awareness suggest that SCAD is more prevalent than prior estimates. SCAD is associated with female sex, young age, extreme emotional stress, or extreme exertion, pregnancy, and fibromuscular dysplasia. The clinical characteristics and management strategies of SCAD patients are different than for atherosclerotic heart disease and deserve specific consideration. This review will highlight recent discoveries about SCAD as well as describe current efforts to elucidate remaining gaps in knowledge.

  16. Automated carotid artery intima layer regional segmentation

    Energy Technology Data Exchange (ETDEWEB)

    Meiburger, Kristen M; Molinari, Filippo [Biolab, Department of Electronics, Politecnico di Torino, Torino (Italy); Acharya, U Rajendra [Department of ECE, Ngee Ann Polytechnic (Singapore); Saba, Luca [Department of Radiology, A.O.U. di Cagliari, Cagliari (Italy); Rodrigues, Paulo [Department of Computer Science, Centro Universitario da FEI, Sao Paulo (Brazil); Liboni, William [Neurology Division, Gradenigo Hospital, Torino (Italy); Nicolaides, Andrew [Vascular Screening and Diagnostic Centre, London (United Kingdom); Suri, Jasjit S, E-mail: filippo.molinari@polito.it [Fellow AIMBE, CTO, Global Biomedical Technologies Inc., CA (United States)

    2011-07-07

    Evaluation of the carotid artery wall is essential for the assessment of a patient's cardiovascular risk or for the diagnosis of cardiovascular pathologies. This paper presents a new, completely user-independent algorithm called carotid artery intima layer regional segmentation (CAILRS, a class of AtheroEdge(TM) systems), which automatically segments the intima layer of the far wall of the carotid ultrasound artery based on mean shift classification applied to the far wall. Further, the system extracts the lumen-intima and media-adventitia borders in the far wall of the carotid artery. Our new system is characterized and validated by comparing CAILRS borders with the manual tracings carried out by experts. The new technique is also benchmarked with a semi-automatic technique based on a first-order absolute moment edge operator (FOAM) and compared to our previous edge-based automated methods such as CALEX (Molinari et al 2010 J. Ultrasound Med. 29 399-418, 2010 IEEE Trans. Ultrason. Ferroelectr. Freq. Control 57 1112-24), CULEX (Delsanto et al 2007 IEEE Trans. Instrum. Meas. 56 1265-74, Molinari et al 2010 IEEE Trans. Ultrason. Ferroelectr. Freq. Control 57 1112-24), CALSFOAM (Molinari et al Int. Angiol. (at press)), and CAUDLES-EF (Molinari et al J. Digit. Imaging (at press)). Our multi-institutional database consisted of 300 longitudinal B-mode carotid images. In comparison to semi-automated FOAM, CAILRS showed the IMT bias of -0.035 {+-} 0.186 mm while FOAM showed -0.016 {+-} 0.258 mm. Our IMT was slightly underestimated with respect to the ground truth IMT, but showed uniform behavior over the entire database. CAILRS outperformed all the four previous automated methods. The system's figure of merit was 95.6%, which was lower than that of the semi-automated method (98%), but higher than that of the other automated techniques.

  17. Role of radial artery in total arterial myocardial revascularization in coronary bypass surgery

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Background Total arterial revascularization (TAR) was widely utilized in coronary artery bypass grafting (CABG) as a result of its better long-term effect compared with vein grafts.Of the arterial conduits,radial artery (RA) gained popularity for its easy availability and reported long-term patency.Thus,the objective of this study was to investigate the effect of RA in TAR in CABG.Methods From January 2000 to December 2006,85 patients (56 male and 29 female) at a mean age of 57.0±5.2 years,underwent TAR in CABG RA and left internal mammary artery (LIMA) with composite Y or T and seauential grafting techniques were used.Post-operative complications were recorded and follow-up was performed.Results Eighty-five LIMA and 149 RA grafts including 21 single and 64 bilateral RA were collected.A total of 87 distal anastomoses were done with the LIMA and another 152 were done with the RA,with the mean number of diStal anastOmosis per patient of 2.81±0.47.The proximal RA ends were anastomsed directly to the aorta in 140 grafts with Y or T graft off in situ LIMA in 9,Yor T graft off Rain 9.The distal end was anastomsed to right coronary artery system in 92,to Obtuse margma in 46,to diagonal in 19 and to ramous intermedius in 5.Nine sequential anastomoses were Derformed with RA.Nine composite Y or T grafts were constructed with RA and LIMA while another 9 were constructed with RA and RA.One (1.2%) patient died,3 patients (3.5%) experienced acute renal failure and 2 (2.4%) developed stroke.All patienfs were still alive and no patient had evidences of newly occurred myocardial infarction or angina after a mean tollow-up of 36.5±4.1 months (6-67 months).Postoperatively at 6 month,mean left ventricular ejective fraction was increased to 0.49±0.09,compared with that of 0.43±0.11 preoperatively (P=0.027).Postoperative mean New York Heart Association class was 2.5±0.5,compared with that of 3.0±0.4 preoperatively (P=0.003).Conclusions TAR with arterial conduits of which RA was

  18. Middle meningeal artery arising from the basilar artery.

    Science.gov (United States)

    Salem, Mohamed M; Fusco, Matthew R; Dolati, Parviz; Reddy, Arra S; Gross, Bradley A; Ogilvy, Christopher S; Thomas, Ajith J

    2014-12-01

    Various anomalies for the origin of the middle meningeal artery (MMA) have been described in the literature. However, origin of the MMA from the basilar trunk is an extremely rare variant. We report on a 54-year-old female who presented with frequent headaches; magnetic resonance imaging showed a right parietal meningioma. The abnormal origin of the middle meningeal artery from the basilar artery was diagnosed by angiography performed for preoperative embolization of the tumor. We report on the case with a review of the embryologic basis, possible explanations for this aberrant origin, and its clinical implications.

  19. Off-pump coronary artery bypass grafting or percutaneous transluminal coronary angioplasty with stenting for proximal left anterior descending coronary artery disease?

    NARCIS (Netherlands)

    Drenth, Derk Jan

    2005-01-01

    This thesis describes and discusses the results of a prospective randomized controlled clinical trial comparing percutaneous coronary angioplasty with stenting (stenting) and off-pump coronary artery bypass grafting with a left internal mammary artery (surgery) in patients with a high-grade stenosis

  20. EXERCISE-INDUCED ARTERIAL ADAPTATIONS IN ELITE JUDO ATHLETES

    Directory of Open Access Journals (Sweden)

    Panagiotis Karagounis

    2009-09-01

    Full Text Available The purpose of this study was to examine exercise-induced arterial adaptations in elite Judo male and female athletes. 27 male Judo athletes (age 24.06 ± 2 years, 11 female Judoka (age 24.27 ± 1 years, 27 sedentary healthy men (age 24.01 ± 2 years and 11 women (age 24.21 ± 1 years participated in the current study. The examined vessels included brachial, radial, ulnar, popliteal, anterior and posterior tibial arteries. The experimental parameters were recorded with the use of Duplex ultrasound at rest. Diastolic diameter and blood mean flow velocity of the examined arteries in Judo athletes were found to be both significantly increased (p < 0.05 compared to the findings of the control groups. In male Judo athletes the brachial (p < 0.001, radial (p < 0.001, and anterior tibial artery (p < 0.001 presented the highest difference on the diastolic diameter, compared with the control male group. In female Judo athletes, ulnar (p < 0.001, radial (p < 0.001, and brachial (p < 0.001 arteries illustrated the highest diastolic diameter. The highest blood mean flow velocity was recorded in ulnar (p < 0.001 and popliteal arteries (p < 0.001 of the Judo athletes groups. Recording differences between the two genders, male participants presented larger arteries than females. Conclusively, Judo has been found to be a highly demanding physical sport, involving upper and lower limbs leading to significant arterial adaptations. Obtaining vascular parameters provide a useful tool to the medical team, not only in the direction of enhancement of the efficacy of physical training, but in unknown so far parameters that may influence athletic performance of both male and female elite Judokas

  1. Finite elements of nonlinear continua

    CERN Document Server

    Oden, J T

    2000-01-01

    Geared toward undergraduate and graduate students, this text extends applications of the finite element method from linear problems in elastic structures to a broad class of practical, nonlinear problems in continuum mechanics. It treats both theory and applications from a general and unifying point of view.The text reviews the thermomechanical principles of continuous media and the properties of the finite element method, and then brings them together to produce discrete physical models of nonlinear continua. The mathematical properties of these models are analyzed, along with the numerical s

  2. FINITE ELEMENT ANALYSIS OF STRUCTURES

    Directory of Open Access Journals (Sweden)

    PECINGINA OLIMPIA-MIOARA

    2015-05-01

    Full Text Available The application of finite element method is analytical when solutions can not be applied for deeper study analyzes static, dynamic or other types of requirements in different points of the structures .In practice it is necessary to know the behavior of the structure or certain parts components of the machine under the influence of certain factors static and dynamic . The application of finite element in the optimization of components leads to economic growth , to increase reliability and durability organs studied, thus the machine itself.

  3. Total Arterial Revascularization with Internal Mammary Artery or Radial Artery Graft Configuration

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    To investigate the clinical use of π graft in total arterial revascularization and its outcomes, a retrospective analysis of 23 patients out of 1000 patients undergoing total arterial coronary bypass surgery with a π graft between September 1994 and December 2004 was performed. In the selected patients for the management of triple vessel disease with middle diagonal/intermediate ramus disease such that a skip with the left internal mammary artery (LIMA) or radial artery (RA),the main stem of π graft, to the left anterior descending coronary artery (LAD) will not work and the right internal mammary artery (RIMA) or right gastroepiploic artery (RGEA) cannot pick up the diagonal/intermediate ramus, hence the LAD and diagonal/intermediate ramus were grafted with a mini Y graft using the distal segment of LIMA, RIMA, RA or RGEA, together with the bilateral internal mammary artery (BIMA) or LIMA-RA T graft to compose π graft. Twenty-three patients (18 males, 5 females) underwent the π graft procedure. There were no deaths or episodes of myocardial infarction, stroke, and deep sternal wound infection. One patient required reopening for controlling bleeding. Until the end of 2004, during a mean follow-up of 81.0 ±28.4 months, no angina needing re-intervention or operative therapy or coronary related death occurred. In conclusion, in patients with specific coronary artery anatomy/stenosis, the BIMA (sometimes LIMA with RA or RGEA) π graft can be successfully performed for total arterial revascularization with good midterm outcomes.

  4. Accurate finite difference beam propagation method for complex integrated optical structures

    DEFF Research Database (Denmark)

    Rasmussen, Thomas; Povlsen, Jørn Hedegaard; Bjarklev, Anders Overgaard

    1993-01-01

    A simple and effective finite-difference beam propagation method in a z-varying nonuniform mesh is developed. The accuracy and computation time for this method are compared with a standard finite-difference method for both the 3-D and 2-D versions......A simple and effective finite-difference beam propagation method in a z-varying nonuniform mesh is developed. The accuracy and computation time for this method are compared with a standard finite-difference method for both the 3-D and 2-D versions...

  5. Cerebellar arteries originating from the internal carotid artery: angiographic evaluation and embryologic explanations

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Young; Han, Moon Hee; Yu, In Gyu; Chang, Ki Hyun [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of); Kim, Eui Jong [Kyunghee Univ. College of Medicine, Seoul (Korea, Republic of); Kim, Dae Ho [Soonchunhyang Univ. College of Medicine, Asan(Korea, Republic of)

    1997-06-01

    To find and describe the cerebellar arteries arising from the internal carotid artery, explain them embryologically, and evaluate their clinical implication. To determine the point in the internal carotid artery from which the cereballar artery arose anomalously, consecutive angiographic studies performed in the last three years were reviewed. The distribution of such anomalous cerebellar arteries, the point in the internal carotid artery from which the anomalous vessels originated, and associated findings were analyzed. Five anomalous origins of cerebellar arteries arising arising directly from the internal carotid artery were found in five patients. Three anterior inferior cerebellar arteries (AICA) and one common trunk of an AICA and a posterior inferior cerebellar artery (PICA) were found to originate from the internal carotid artery at a point close to the origin of the primitive trigeminal artery. A PICA arose from an artery presenting a course similar to the proatlantal intersegmental artery. Intracranial aneurysms in two patients, Moyamoya disease in one, and facial arteriovenous malformation in one. In our series, AICAs supplied from the arteries considered to be persistent trigeminal artery variants were the most common type. A correlation between type of anomalous cerebellar artery and type of carotid-vertebrobasilar anastomosis may exist. Cerebellar arteries originating anomalously from the internal carotid artery seem to occur as a result of the persistence of carotid-vertebrobasilar anastomoses associated with incomplete fusion of the longitudinal neural arteries. An understanding of these anomalous cerebellar arteries may help prevent accidents during therapeutic embolization and surgical treatment, as well as misinterpretation.

  6. Induction of anesthesia in coronary artery bypass graft surgery: the hemodynamic and analgesic effects of ketamine

    OpenAIRE

    Elif Basagan-Mogo; Suna Goren; Gulsen Korfali; Gurkan Turker; Fatma Nur Kaya

    2010-01-01

    OBJECTIVE: The aim of this prospective, randomized study was to evaluate the hemodynamic and analgesic effects of ketamine by comparing it with propofol starting at the induction of anesthesia until the end of sternotomy in patients undergoing coronary artery bypass grafting surgery. INTRODUCTION: Anesthetic induction and maintenance may induce myocardial ischemia in patients with coronary artery disease. A primary goal in the anesthesia of patients undergoing coronary artery bypass grafting ...

  7. Embolisation of the splenic artery

    Energy Technology Data Exchange (ETDEWEB)

    Essler, G.; Duex, A.

    1982-09-01

    In bleeding of oesophageal varices with resistance to common treatment embolisation of the splenic artery causes depression of the portal hypertension by forty per cent. Thrombosis of the splenic or portal vein as in splenectomies are not to be expected. The splenic vein remains open for later spleno-renal anastomosis. By occlusion of the splenic artery we were successful in stopping oesophageal bleeding. In a patient with dominant hypersplenism in portal hypertension the severity of the syndrome decreased after embolisation of the splenic artery. Thrombocytes, leukocytes and gammaglobulin increased.

  8. Access to the ophthalmic artery by retrograde approach through the posterior communicating artery for intra-arterial chemotherapy of retinoblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Chi-Tuan; Blanc, Raphael; Pistocchi, Silvia; Bartolini, Bruno; Piotin, Michel [Fondation Rothschild Hospital, Department of Interventional Neuroradiology, Paris (France); Lumbroso-Le Rouic, Livia [Institut Curie, Department of Ocular Oncology, Paris (France)

    2012-08-15

    Intra-arterial infusion of chemotherapy into the ophthalmic artery for treatment of retinoblastoma has been realized after catheterization of the internal carotid and temporary balloon occlusion beyond the orifice of the ophthalmic artery, or more recently after superselective canulation of the ophthalmic artery by a microcatheter. The superselective catheterization of the ophthalmic artery could be cumbersome because of the implantation of the ostium on the carotid siphon or because of the tortuosity of the carotid siphon. We report our experience of using a retrograde approach through the posterior communicating artery that allows a more direct angle of access to the origin of the ophthalmic artery. (orig.)

  9. Implicit finite-difference simulations of seismic wave propagation

    KAUST Repository

    Chu, Chunlei

    2012-03-01

    We propose a new finite-difference modeling method, implicit both in space and in time, for the scalar wave equation. We use a three-level implicit splitting time integration method for the temporal derivative and implicit finite-difference operators of arbitrary order for the spatial derivatives. Both the implicit splitting time integration method and the implicit spatial finite-difference operators require solving systems of linear equations. We show that it is possible to merge these two sets of linear systems, one from implicit temporal discretizations and the other from implicit spatial discretizations, to reduce the amount of computations to develop a highly efficient and accurate seismic modeling algorithm. We give the complete derivations of the implicit splitting time integration method and the implicit spatial finite-difference operators, and present the resulting discretized formulas for the scalar wave equation. We conduct a thorough numerical analysis on grid dispersions of this new implicit modeling method. We show that implicit spatial finite-difference operators greatly improve the accuracy of the implicit splitting time integration simulation results with only a slight increase in computational time, compared with explicit spatial finite-difference operators. We further verify this conclusion by both 2D and 3D numerical examples. © 2012 Society of Exploration Geophysicists.

  10. Finite Element Model Updating Using Response Surface Method

    CERN Document Server

    Marwala, Tshilidzi

    2007-01-01

    This paper proposes the response surface method for finite element model updating. The response surface method is implemented by approximating the finite element model surface response equation by a multi-layer perceptron. The updated parameters of the finite element model were calculated using genetic algorithm by optimizing the surface response equation. The proposed method was compared to the existing methods that use simulated annealing or genetic algorithm together with a full finite element model for finite element model updating. The proposed method was tested on an unsymmetri-cal H-shaped structure. It was observed that the proposed method gave the updated natural frequen-cies and mode shapes that were of the same order of accuracy as those given by simulated annealing and genetic algorithm. Furthermore, it was observed that the response surface method achieved these results at a computational speed that was more than 2.5 times as fast as the genetic algorithm and a full finite element model and 24 ti...

  11. Peripancreatic artery ligation and artery infusion chemotherapy for advanced pancreatic carcinoma

    Institute of Scientific and Technical Information of China (English)

    纪宗正; 王永向; 陈熹; 吴涛

    2003-01-01

    Objective To develop a new treatment for advanced pancreatic carcinoma. Methods Twenty-nine patients with advanced pancreatic carcinoma (12 patients with liver metastasis at the same time) were randomly divided into two groups. In group A (n=11), patients underwent bilio-enterostomy and/or gastro-enterostomy combined with systemic chemotherapy after surgery. In group B (n=18), patients underwent bilio-enterostomy and/or gastro-enterostomy combined with peripancreatic arterial ligation and arterial infusion regional chemotherapy. Twenty-four patients were followed up for 3-18 months. The palliation of clinical symptoms, changes in carcinoma size by B ultrasound (BUS) and CT scan, survival period and serum carcinoembryonic antigen (CEA) were observed and compared between the two groups. Results Symptoms were alleviated in most patients in group B, and BUS and CT scan showed that tumor volume decreased in group B. The response rate was 66.7% in group B and 18.2% in group A (P0.05). Conclusion Peripancreatic arterial ligation combined with arterial infusion regional chemotherapy is effective against both pancreatic carcinoma and with liver metastases. It can alleviate clinical symptoms, postpone the growth rate of tumor and prolong the survival period.

  12. Finite-dimensional (*)-serial algebras

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Let A be a finite-dimensional associative algebra with identity over a field k. In this paper we introduce the concept of (*)-serial algebras which is a generalization of serial algebras. We investigate the properties of (*)-serial algebras, and we obtain suficient and necessary conditions for an associative algebra to be (*)-serial.

  13. Essays on Finite Mixture Models

    NARCIS (Netherlands)

    A. van Dijk (Bram)

    2009-01-01

    textabstractFinite mixture distributions are a weighted average of a ¯nite number of distributions. The latter are usually called the mixture components. The weights are usually described by a multinomial distribution and are sometimes called mixing proportions. The mixture components may be the sam

  14. 体外循环及非体外循环冠状动脉旁路移植术后患者急性胃肠功能损伤的对比研究%Incidence of Acute Gastrointestinal Injury After On -pump and Off -pump Coronary Artery Bypass Surgery:A Comparative Study

    Institute of Scientific and Technical Information of China (English)

    吴昆鹏; 陈莹; 言彩红; 张凤文; 李方; 黄治家

    2015-01-01

    目的:比较体外循环及非体外循环冠状动脉旁路移植术后患者急性胃肠功能损伤的发生情况。方法回顾性分析2010年1月—2012年12月南华大学附属第二医院行冠状动脉旁路移植术治疗的冠心病患者536例,根据手术方式分为体外循环组412例,非体外循环组124例。观察两组患者一般情况、基础疾病、超声心动图结果、术后血流动力学、血管活性药物总量、日均尿量,术后急性胃肠功能损伤发生率及急性胃肠功能损伤分级。结果体外循环组与非体外循环组患者性别、年龄、体质量、纽约心脏病学会( NYHA )心功能分级、高血压发生率、糖尿病发生率、高脂血症发生率、慢性阻塞性肺疾病发生率、左心室舒张末期内径、左心室射血分数、术后日均心率、日均动脉压、日均中心静脉压、血管活性药物总量(去甲肾上腺素、多巴胺、多巴酚丁胺、肾上腺素)比较,差异均无统计学意义(P>0.05);体外循环组患者日均尿量较非体外循环组增多(P<0.05)。体外循环组22例(5.3%)发生急性胃肠功能损伤,其中Ⅰ级7例、Ⅱ级13例、Ⅲ级1例、Ⅳ级1例;非体外循环组6例(4.8%)发生急性胃肠功能损伤,均为Ⅰ级。两组患者急性胃肠功能损伤发生率比较,差异无统计学意义(χ2=0.048, P=0.519)。结论体外循环与非体外循环冠状动脉旁路移植术后患者急性胃肠功能损伤发生率无差异,但非体外循环冠状动脉旁路移植术后均为Ⅰ级。%Objective To compare the incidence of acute gastrointestinal injury ( AGI) after on -pump and off -pump coronary artery bypass surgery .Methods Conducted a retrospective analysis on 536 patients with coronary heart disease who received coronary artery bypass surgery in the Second Hospital Affiliated to South China University from January 2010 to December 2012.According to

  15. Comparative study on hepatic artery CO2-DSA and conventional-DSA in patients with liver cancer after iodine%肝癌患者经肝动脉 CO2-DSA 和常规碘-DSA诊断的对照研究

    Institute of Scientific and Technical Information of China (English)

    秦伟; 胡天刚; 赵景昊; 姜扬; 鲁云伟; 王海英; 漆素兰

    2014-01-01

    Objective To investigate the clinical efficacy and safety in patients with hepatocellular carcinoma after hepatic artery CO2-DSA and conventionaliodine-DSA ,for clinical use of CO2-DSA technology for the liver cancer patients for further diagnosis provides the reference value .Methods A total of 282 cases of hepatocellular carcinoma patients in our hospitaloncology and were divided into observation group (150 cases) and control group (132 cases) by transcatheter arterial CO2-DSA ,the control group using conventionaliodine-DSA via hepatic artery ,compared with two groups of portal vein tumor thrombus in the portal vein display ,display rate of fistula ,arteriovenous differences ,diag-nosis the image quality ,the adverse reaction rate index .Results To observe the image quality group for level 1 of the 139 cases ,98 cases were significantly higher than control group ,quality level 3 in 3 cases was less than 13 cases in the control group ,statistically significant 3 level two groups of image quality difference (P<0 .05);observation group (4 .6 ± 0 .4) portal vein was showed significantly higher scores in the control group (3 .8 ± 0 .7) ,observation group (2 .7 ± 0 .3) contour display scores were higher than those in the control group was (2 .1 ± 0 .6) ,the adverse reactions observed score was 1 .2 ± 0 .4 ,significantly lower than the control group (2 .8 ± 0 .9) ,with statistical significance of the a-bove index difference between the two groups (P<0 .05) .For observation group ,the hepatic artery and portal vein fistula ,hepatic artery hepatic vein fistula ,portal vein tumor thrombus was showed 63 (42% ) , 35 (23 .33% ) , 25 (16 .67% ) was significantly higher than that in control group 38 (28 .79% ) ,17 (12 .88% ) ,11 (8 .33% ) ,more than two sets of each index statistics difference was statistically significance (P<0 .05) .Conclusion It can improve the diagnostic image quality ,improve the accuratediagnosis rate ,reduce the adverse reaction occurred via

  16. Effect of Body Acceleration on Pulsatile Flow of Micropolar Fluid through an Irregular Arterial Stenosis

    Science.gov (United States)

    Abdullah, Ilyani; Amin, Norsarahaida

    2008-01-01

    The present study deals with the effect of body acceleration together with surface irregularities on blood flow in artery. Prolonged exposure to high level unintended acceleration may cause serious health problems in the cardiovascular system. The situations like riding in vehicles, flying in airplanes and fast body movements during sport activities can lead to the impairment of certain physiological functions. A micropolar model of blood flow through an irregular arterial stenosis is considered. The governing equations involving unsteady nonlinear two-dimensional partial differential equations are solved employing finite difference scheme. Computational results on the velocity profiles and the flow characteristics are presented.

  17. 256层ICT探测冠状动脉钙化在不稳定心绞痛与稳定心绞痛患者中的对比%Detection of Coronary Artery Calcification Score and Compare it in Patients Diagnosed Clinically as Stable and Unstable Angina by 256 ICT

    Institute of Scientific and Technical Information of China (English)

    朱大光

    2013-01-01

    目的:探讨256层ICT在探测冠状动脉钙化积分中的意义。方法:采用256层ICT对2组患者进行冠状动脉钙化积分扫描,钙化积分由工作站软件自动获得,132例患者分为2组,55例稳定心绞痛,77不例稳定心绞痛。结果:不稳定心绞痛患者的钙化积分要显著大于稳定心绞痛患者(p<0.05),不稳定心绞痛患者的血管钙化数目要明显多于稳定心绞痛组。结论:不稳定心绞痛患者的钙化更明显,因此预测冠状动脉情况冠状动脉钙化积分可以作为重要指标。%Objective:To detect Coronary calcification score and compare it in patients diagnosed clinically of having stable and unsta -ble angina and they being more prone for cardiovascular risk .Methods:Coronary artery calcification was scanned and its scores ( CACS) were measured through 256-slice ICT in 132 patients diagnosed of having stable and unstable angina .(55 stable and 77 unstable angi-na).the result were analyzed statistically by 2-grouped test.Also some associated risk factors were also taken into concideraton (HTN, total cholesterol ,Triglycerides etc ) .Results:The calcification scores in patients with unstable angina were comparatively more than those with patients having stable angina (p<0.05).Also it found that 3-vesssel calcification was more significant with unstable angina ,where as 1-vesssel calcification was more significant with stable angina cases .Conclusion:Coronary artery calcification scores is of great value in predicting cardiovascular enets .

  18. Isotropy and anisotropy of the arterial wall.

    Science.gov (United States)

    Weizsacker, H W; Pinto, J G

    1988-01-01

    The passive biomechanical response of intact cylindrical rat carotid arteries is studied in vitro and compared with the mechanical response of rubber tubes. Using true stress and natural strain in the definition of the incremental modulus of elasticity, the tissue wall properties are analyzed over wide ranges of simultaneous circumferential and longitudinal deformations. The type of loading chosen is 'physiological' i.e. symmetric: the cylindrical segments are subjected to internal pressure and axial prestretch without torsion or shear. Several aspects pertaining to the choice of parameters characterizing the material are discussed and the analysis pertaining to the deformational behavior of a hypothetical compliant tube with Hookean wall material is presented. The experimental results show that while rubber response can be adequately represented as linearly elastic and isotropic, the overall response of vascular tissue is highly non-linear and anisotropic. However, for states of deformation that occur in vivo, the elasticity of arteries is quite similar to that of rubber tubes and as such the arterial wall may be viewed as incrementally isotropic for the range of deformations that occur in vivo.

  19. Finite Canonical Measure for Nonsingular Cosmologies

    CERN Document Server

    Page, Don N

    2011-01-01

    The total canonical (Liouville-Henneaux-Gibbons-Hawking-Stewart) measure is finite for completely nonsingular Friedmann-Robertson-Walker classical universes with a minimally coupled massive scalar field and a positive cosmological constant. For a cosmological constant very small in units of the square of the scalar field mass, most of the measure is for nearly de Sitter solutions with no inflation at a much more rapid rate. However, if one restricts to solutions in which the scalar field energy density is ever more than twice the equivalent energy density of the cosmological constant, then the number of e-folds of rapid inflation must be large, and the fraction of the measure is low in which the spatial curvature is comparable to the cosmological constant at the time when it is comparable to the energy density of the scalar field. The measure for such classical FRW-Lambda-phi models with both a big bang and a big crunch is also finite. Only the solutions with a big bang that expand forever, or the time-revers...

  20. Vein graft adaptation and fistula maturation in the arterial environment.

    Science.gov (United States)

    Lu, Daniel Y; Chen, Elizabeth Y; Wong, Daniel J; Yamamoto, Kota; Protack, Clinton D; Williams, Willis T; Assi, Roland; Hall, Michael R; Sadaghianloo, Nirvana; Dardik, Alan

    2014-05-01

    Veins are exposed to the arterial environment during two common surgical procedures, creation of vein grafts and arteriovenous fistulae (AVF). In both cases, veins adapt to the arterial environment that is characterized by different hemodynamic conditions and increased oxygen tension compared with the venous environment. Successful venous adaptation to the arterial environment is critical for long-term success of the vein graft or AVF and, in both cases, is generally characterized by venous dilation and wall thickening. However, AVF are exposed to a high flow, high shear stress, low-pressure arterial environment and adapt mainly via outward dilation with less intimal thickening. Vein grafts are exposed to a moderate flow, moderate shear stress, high-pressure arterial environment and adapt mainly via increased wall thickening with less outward dilation. We review the data that describe these differences, as well as the underlying molecular mechanisms that mediate these processes. Despite extensive research, there are few differences in the molecular pathways that regulate cell proliferation and migration or matrix synthesis, secretion, or degradation currently identified between vein graft adaptation and AVF maturation that account for the different types of venous adaptation to arterial environments.

  1. Vein graft adaptation and fistula maturation in the arterial environment

    Science.gov (United States)

    Lu, Daniel Y; Chen, Elizabeth Y; Wong, Daniel J; Yamamoto, Kota; Protack, Clinton D; Williams, Willis T; Assi, Roland; Hall, Michael R; Sadaghianloo, Nirvana; Dardik, Alan

    2014-01-01

    Veins are exposed to the arterial environment during two common surgical procedures, creation of vein grafts and arteriovenous fistulae (AVF). In both cases veins adapt to the arterial environment that is characterized by different hemodynamic conditions and increased oxygen tension compared to the venous environment. Successful venous adaptation to the arterial environment is critical for long term success of the vein graft or AVF, and in both cases is generally characterized by venous dilation and wall thickening. However, AVF are exposed to a high flow, high shear stress, low pressure arterial environment, and adapt mainly via outward dilation with less intimal thickening. Vein grafts are exposed to a moderate flow, moderate shear stress, high pressure arterial environment, and adapt mainly via increased wall thickening with less outward dilation. We review the data that describe these differences, as well as the underlying molecular mechanisms that mediate these processes. Despite extensive research, there are few differences in the molecular pathways that regulate cell proliferation and migration or matrix synthesis, secretion, or degradation currently identified between vein graft adaptation and AVF maturation that account for the different types of venous adaptation to arterial environments. PMID:24582063

  2. Audiometric changes after coronary artery bypass graft

    Directory of Open Access Journals (Sweden)

    Khorsandi M T

    2007-09-01

    Full Text Available Background: Hearing is one of the most significant senses; There fore, any defect can be frightening. The incidence of sever hearing loss following coronary artery bypass surgery has been estimated as one per thousand. This Prospective study carried out to determine hearing effects of coronary artery bypass surgery."nMethods: age, audiometric changes before and after surgery (hearing levels at multiple frequencies, speech reception threshold and speech discrimination score, minimum blood pressure during the operation, and the time on bypass, measured on One hundred consecutive patients who candidate for coronary artery bypass surgery and the results analysed."nResults: One hundred patients completed the tests. Based on hearing changes found on pre- and post-operative tests, the patients were divided into 3 groups: Those with no change (47 patients according to their audiometric results; those with slight changes ≤10 db (43 patients; and those having average deficits of more than 10 db (10 patients. All the patients were male. None of the patients had complete or severe sensorineural hearing loss. The third group had more prolonged pumping duration when compared with the others groups (p=0.002. Furthermore, 90 percent of patients with a sensorineural hearing loss more than 10 db had diabetes mellitus and hyperlipidemia as risk factors."nConclusion: Sudden sensorineural hearing loss is a sequela in patients who undergoing coronary artery bypass surgery; however, it was usually mild and asymptomatic. Pumping time during the operation is a significant factor in occurring of this complication. With proper treatment of underlying diseases and eliminating the risk factors with improvement of our cardiopulmonary pumps we probably can get better hearing results.

  3. Thrombophilia And Arterial Ischemic Stroke

    Directory of Open Access Journals (Sweden)

    A.A. Abrishamizadeh

    2017-02-01

    Full Text Available Ischemic stroke (IS is a common cause of morbidity and mortality with significant socioeconomic impact especially when it affects young patients. Compared to the older adults, the incidence, risk factors, and etiology are distinctly different in younger IS. Hypercoagulable states are relatively more commonly detected in younger IS patients. Thrombophilic states are disorders of hemostatic mechanisms that result in a predisposition to thrombosis .Thrombophilia is an established cause of venous thrombosis. Therefore, it is tempting to assume that these disorders might have a similar relationship with arterial thrombosis. Despite this fact that 1-4 % of ischemic strokes are attributed to Thrombophillia, this   alone rarely causes arterial occlusions .Even in individuals with a positive thrombophilia screen and arterial thrombosis, the former might not be the primary etiological factor. Thrombophilic   disorders can be broadly divided into inherited or acquired conditions. Inherited thrombophilic states include deficiencies of natural anticoagulants such as protein C, protein S, and antithrombin III (AT III deficiency, polymorphisms causing resistance to activated protein C(Factor V Leiden mutation, and disturbance in the clotting balance (prothrombin gene 20210G/A variant. Of all the inherited  thrombophilic disorders, Factor V Leiden mutation is perhaps the commonest cause. On the contrary, acquired thrombophilic disorders are more common and include conditions such as the antiphospholipid syndrome, associated with lupus anticoagulant and anticardiolipin antibodies. The more useful and practical approach of ordering various diagnostic tests for the uncommon thrombophilic states tests should be determined by a detailed clinical history, physical examination, imaging studies and evaluating whether an underlying hypercoagulable state appears more likely. The laboratory thrombophilia   screening should be comprehensive and avoid missing the

  4. Non-Newtonian effects of blood on LDL transport inside the arterial lumen and across multi-layered arterial wall with and without stenosis

    Science.gov (United States)

    Deyranlou, Amin; Niazmand, Hamid; Sadeghi, Mahmood-Reza; Mesri, Yaser

    2016-06-01

    Blood non-Newtonian behavior on low-density lipoproteins (LDL) accumulation is analyzed numerically, while fluid-multilayered arteries are adopted for nonstenotic and 30%-60% symmetrical stenosed models. Present model considers non-Newtonian effects inside the lumen and within arterial layers simultaneously, which has not been examined in previous studies. Navier-Stokes equations are solved along with the mass transport convection-diffusion equations and Darcy’s model for species transport inside the luminal flow and across wall layers, respectively. Carreau model for the luminal flow and the modified Darcy equation for the power-law fluid within arterial layers are employed to model blood rheological characteristics, appropriately. Results indicate that in large arteries with relatively high Reynolds number Newtonian model estimates LDL concentration patterns well enough, however, this model seriously incompetent for regions with low WSS. Moreover, Newtonian model for plasma underestimates LDL concentration especially on luminal surface and across arterial wall. Therefore, applying non-Newtonian model seems essential for reaching to a more accurate estimation of LDL distribution in the artery. Finally, blood flow inside constricted arteries demonstrates that LDL concentration patterns along the stenoses inside the luminal flow and across arterial layers are strongly influenced as compared to the nonstenotic arteries. Additionally, among four stenosis severity grades, 40% stenosis is prone to more LDL accumulation along the post-stenotic regions.

  5. Idiopathic arterial calcification in childhood

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Maya [Department of Paediatric Radiology, Red Cross Children' s Hospital, Cape Town (South Africa); Red Cross Children' s Hospital, School of Child and Adolescent Health, University of Cape Town, Klipfontein Road, Rondebosch, Cape Town (South Africa); Andronikou, Savvas; Solomon, Rustum; Sinclair, Paul; McCulloch, Mignon [Department of Paediatric Radiology, Red Cross Children' s Hospital, Cape Town (South Africa)

    2004-08-01

    Idiopathic arterial calcification in infancy is usually fatal with death in early life and diagnosis at post mortem. This report describes a unique, late presentation with hypertension and cardiac failure in a child aged 33 months, found to have widespread arterial calcification at radiological imaging. The calcium-phosphate axis was normal and there was no other demonstrable cause for calcification. Additionally, the histological features of arterial calcification at renal biopsy paralleled the findings in infants with this disorder. The late presentation in this case is unusual and has not been previously reported. Ultrasound and CT are sensitive for calcification, and the disease should be suspected in children presenting with cardiac or respiratory manifestations and features of arterial calcification, where no metabolic cause is established. (orig.)

  6. Peripheral Artery Disease and Diabetes

    Science.gov (United States)

    ... Venous Thromboembolism Aortic Aneurysm More Peripheral Artery Disease & Diabetes Updated:Jan 26,2016 People with diabetes are ... life. This content was last reviewed January 2016. Diabetes • Home • About Diabetes • Why Diabetes Matters Introduction Cardiovascular ...

  7. Robotics and coronary artery surgery.

    Science.gov (United States)

    Magee, Mitchell J; Mack, Michael J

    2002-11-01

    Significant progress in cardiac surgery, and specifically the surgical management of coronary artery disease, has been due in large part to enabling technology. Robotic systems have been recently developed and refined for use in cardiac surgery to facilitate, among other procedures, a totally endoscopic approach to coronary artery bypass surgery. These systems enhance precision through endoscopic approaches by specifically addressing the inherent limitations of conventional endoscopic coronary microsurgical instrumentation via computerized, digital interface, telemanipulation technology. With a combined experience of 125 patients, several groups have independently demonstrated the clinical feasibility of totally endoscopic coronary artery bypass with two commercially available robotic telemanipulation systems. Additional enabling technology is needed to overcome the challenges currently limiting development and widespread application of totally endoscopic off-pump multivessel coronary artery bypass surgery.

  8. Update in pulmonary arterial hypertension.

    Science.gov (United States)

    Mejía Chew, C R; Alcolea Batres, S; Ríos Blanco, J J

    2016-11-01

    Pulmonary arterial hypertension is a rare and progressive disease that mainly affects the pulmonary arterioles (precapillary), regardless of the triggering aetiology. The prevalence of pulmonary hypertension and pulmonary arterial hypertension in Spain is estimated at 19.2 and 16 cases per million inhabitants, respectively. The diagnosis of pulmonary arterial hypertension is based on haemodynamic criteria (mean pulmonary artery pressure ≥25mmHg, pulmonary capillary wedge pressure ≤15mmHg and pulmonary vascular resistance >3 Wood units) and therefore requires the implementation of right cardiac catheterisation. Sequential therapy with a single drug has been used in clinical practice. However, recent European guidelines recommend combined initial therapy in some situations. This review conducts a critical update of our knowledge of this disease according to the latest guidelines and recommendations.

  9. FINITE DIFFERENCE SIMULATION OF LOW CARBON STEEL MANUAL ARC WELDING

    Directory of Open Access Journals (Sweden)

    Laith S Al-Khafagy

    2011-01-01

    Full Text Available This study discusses the evaluation and simulation of angular distortion in welding joints, and the ways of controlling and treating them, while welding plates of (low carbon steel type (A-283-Gr-C through using shielded metal arc welding. The value of this distortion is measured experimentally and the results are compared with the suggested finite difference method computer program. Time dependent temperature distributions are obtained using finite difference method. This distribution is used to obtain the shrinkage that causes the distortions accompanied with structural forces that act to modify these distortions. Results are compared with simple empirical models and experimental results. Different thickness of plates and welding parameters is manifested to illustrate its effect on angular distortions. Results revealed the more accurate results of finite difference method that match experimental results in comparison with empirical formulas. Welding parameters include number of passes, current, electrode type and geometry of the welding process.

  10. The outcome of living related kidney transplantation with multiple renal arteries

    Directory of Open Access Journals (Sweden)

    Hafiz Shahzad Ashraf

    2013-01-01

    Full Text Available The aim of our study was to compare the surgical complications and short-term outcome of renal transplants with single and multiple renal artery grafts. We reviewed the records of 105 kidney transplantations performed consecutively at our institution from July 2006 to May 2010. The data of 33 (31.4% renal transplants with multiple arteries were compared with the 72 transplants with single artery (68.6%, and the incidence of surgical complications, post-transplant hypertension, acute tubular necrosis, acute graft rejection, mean creatinine level, and patient and graft survival was analyzed. We further subdivided the study recipients into three groups: group A (n = 72 with one-renal-artery allografts and one-artery anastomosis, group B (n = 6 with mul-tiple-artery allografts with single-artery anastomosis, and group C (n = 27 with multiple-artery allografts with multiple arterial anasatomosis, and compared their outcome. No significant diffe-rences were observed among the recipients of all the three groups regarding early vascular and urological complications, post-transplant hypertension, acute tubular necrosis, acute rejection, creatinine level, and graft and patient survival. The mean cold ischemia time in groups B and C was significantly higher (P <0.05. One patient in group A developed renal vein thrombosis resulting in graft nephrectomy. None of the patients with multiple renal arteries developed either vascular or urological complications. In conclusion, kidney transplantation using grafts with mul-tiple renal arteries is equally safe as using grafts with single renal artery, regarding vascular, urological complications, as well as patient and graft survival.

  11. Finite Dimensional KP \\tau-functions I. Finite Grassmannians

    CERN Document Server

    Balogh, F; Harnad, J

    2014-01-01

    We study \\tau-functions of the KP hierarchy in terms of abelian group actions on finite dimensional Grassmannians, viewed as subquotients of the Hilbert space Grassmannians of Sato, Segal and Wilson. A determinantal formula of Gekhtman and Kasman involving exponentials of finite dimensional matrices is shown to follow naturally from such reductions. All reduced flows of exponential type generated by matrices with arbitrary nondegenerate Jordan forms are derived, both in the Grassmannian setting and within the fermionic operator formalism. A slightly more general determinantal formula involving resolvents of the matrices generating the flow, valid on the big cell of the Grassmannian, is also derived. An explicit expression is deduced for the Pl\\"ucker coordinates appearing as coefficients in the Schur function expansion of the \\tau-function.

  12. Vascular reactivity of rabbit isolated renal and femoral resistance arteries in renal wrap hypertension.

    Science.gov (United States)

    Khammy, Makhala M; Angus, James A; Wright, Christine E

    2016-02-15

    In rabbits with cellophane renal wrap hypertension, hindquarter and total vascular resistance changes to pressor and depressor agents are amplified compared to those of normotensive rabbits. The aim of the present study was to evaluate the in vitro pharmacodynamics of hypertensive and normotensive rabbit small artery segments isolated from the renal and hindquarter vascular beds. Using wire myography, the full range (Emax) and sensitivity (EC50) to a range of agonists of segments of renal interlobar (≈ 600 µm i.d.), renal arcuate (≈ 250 µm i.d.) and deep femoral branch (≈ 250 µm i.d.) arteries were assessed under normalised conditions of passive tension. Interlobar arteries from hypertensive rabbits were more sensitive (EC50) than those from normotensive rabbits to noradrenaline (6-fold), methoxamine (3-fold) and angiotensin II (3-fold). Arcuate artery reactivity was largely unaffected by hypertension. Deep femoral arteries from hypertensive rabbits had enhanced sensitivity only to noradrenaline (2-fold) and methoxamine (4-fold). Sensitivity to relaxation by acetylcholine was unaffected by hypertension in all arteries. Deep femoral arteries from hypertensive rabbits were more sensitive to sodium nitroprusside than normotensive counterparts. Adenosine caused little relaxation in renal arteries, but full relaxation in deep femoral arteries, unaltered by hypertension. This study found substantial heterogeneity in the pharmacodynamic profile of vessels isolated from different vascular beds and between arterial segments within the kidney. These profiles were differentially affected by hypertension suggesting that hypertension per se is not a resultant of general vascular dysfunction.

  13. Diabetes is a predictor of coronary artery stenosis in patients hospitalized with heart failure.

    Science.gov (United States)

    Kosuga, Tsuneharu; Komukai, Kimiaki; Miyanaga, Satoru; Kubota, Takeyuki; Nakata, Kotaro; Suzuki, Kenichiro; Yamada, Takayuki; Yoshida, Jun; Kimura, Haruka; Yoshimura, Michihiro

    2016-05-01

    In patients with heart failure, coronary artery disease is the most common underlying heart disease, and is associated with increased mortality. However, estimating the presence or absence of coronary artery disease in patients with heart failure is sometimes difficult without coronary imaging. We reviewed 155 consecutive patients hospitalized with heart failure who underwent coronary angiography. The patients were divided into two groups: patients with (N = 59) and without (N = 96) coronary artery stenosis. The clinical characteristics and blood sampling data were compared between the two groups. The patients with coronary artery stenosis were older than those without. The prevalence of diabetes mellitus (DM), dyslipidemia and a history of revascularization was higher in the patients with coronary artery stenosis. Patients with coronary artery stenosis tended to have wall motion asynergy more frequently than those without. On the other hand, the prevalence of atrial fibrillation (AF) was lower in patients with coronary artery stenosis. The serum hemoglobin level and estimated glomerular filtration rate were lower in patients with coronary artery stenosis than in those without. In the multivariate analysis, DM (odds ratio 3.517, 95 % CI 1.601-7.727) was found to be the only the predictor of the presence of coronary artery stenosis in patients with heart failure. In conclusion, coronary imaging is strongly recommended for heart failure patients with DM to confirm the presence of coronary artery stenosis.

  14. Imaging and finite element analysis: a methodology for non-invasive characterization of aortic tissue.

    Science.gov (United States)

    Flamini, Vittoria; Creane, Arthur P; Kerskens, Christian M; Lally, Caitríona

    2015-01-01

    Characterization of the mechanical properties of arterial tissues usually involves an invasive procedure requiring tissue removal. In this work we propose a non-invasive method to perform a biomechanical analysis of cardiovascular aortic tissue. This method is based on combining medical imaging and finite element analysis (FEA). Magnetic resonance imaging (MRI) was chosen since it presents relatively low risks for human health. A finite element model was created from the MRI images and loaded with systolic physiological pressures. By means of an optimization routine, the structural material properties were changed until average strains matched those measured by MRI. The method outlined in this work produced an estimate of the in situ properties of cardiovascular tissue based on non-invasive image datasets and finite element analysis.

  15. Liver cirrhosis and arterial hypertension

    Institute of Scientific and Technical Information of China (English)

    Jens H Henriksen; Soren Moller

    2006-01-01

    Characteristic findings in patients with cirrhosis are vasodilatation with low overall systemic vascular resistance, high arterial compliance, increased cardiac output, secondary activation of counter-regulatory systems (renin-angiotensin-aldosterone system,sympathetic nervous system, release of vasopressin),and resistance to vasopressors. The vasodilatory state is mediated through adrenomedullin, calcitonin generelated peptide, nitric oxide, and other vasodilators,and is most pronounced in the splanchnic area.This constitutes an effective (although relative)counterbalance to increased arterial blood pressure.This review considers the alterations in systemic hemodynamics in patients with cirrhosis in relation to essential hypertension and arterial hypertension of the renal origin. Subjects with arterial hypertension (essential, secondary) may become normotensive during the development of cirrhosis, and arterial hypertension is rarely manifested in patients with cirrhosis, even in cases with renovascular disease and high circulating renin activity. There is much dispute as to the understanding of homoeostatic regulation in cirrhotic patients with manifest arterial hypertension. This most likely includes the combination of vasodilatation and vasoconstriction in parallel.

  16. Off-pump sequential bilateral internal mammary artery grafting combined with selective arterialization of the coronary venous system

    Institute of Scientific and Technical Information of China (English)

    YU Yang; YAN Xiao-lei; WEI Hua; YANG Jun-feng; GU Cheng-xiong

    2011-01-01

    Background Off-pump coronary artery bypass surgery (OPCAB) has been widely applied in recent years as a less invasive method of myocardial revascularization. This study evaluated the sequential bilateral internal mammary artery grafting combined with selective arterialization of the coronary venous system during OPCAB.Methods From April 2004 to August 2010, patients with diffuse right coronary lesions were studied retrospectively and divided into two groups. Group 1 included seventeen patients who underwent this surgery while group 2 included twenty-one patients without right coronary artery surgical therapy. All patients presented with symptoms of angina. Blood flow of bridged vessels was measured. The perioperative ventricular parameters including left ventricular ejection fraction and end diastolic diameter were compared. During follow-up, myocardial nuclide imaging and coronary angiography were carried out.Results Off-pump coronary artery bypass was performed with an average of 3.6 grafts per patient. Hospital mortality was zero. At the time of follow-up, the patients in group 1 recovered better than in group 2 (P<0.05). In both groups, the mean New York Heart Association (NYHA) class and ejection fraction increased significantly (P<0.001) and the mean left ventricular end-diastolic diameter decreased significantly (P <0.05). Myocardial blood supply of inferior wall in group 1 was obviously improved by myocardial nuclide imaging. Coronary angiography for eight patients in group 1 verified that there was blood flow to myocardium in the arterialized vein.Conclusions Sequential bilateral internal mammary artery grafting combined with selective arterialization of the coronary venous system can be performed during OPCAB. A postoperative improvement in the cardiac functions and the quality of life was documented, increasing our expectation for extensive application.

  17. Abnormal pulmonary artery stiffness in pulmonary arterial hypertension: in vivo study with intravascular ultrasound.

    Directory of Open Access Journals (Sweden)

    Edmund M T Lau

    Full Text Available BACKGROUND: There is increasing recognition that pulmonary artery stiffness is an important determinant of right ventricular (RV afterload in pulmonary arterial hypertension (PAH. We used intravascular ultrasound (IVUS to evaluate the mechanical properties of the elastic pulmonary arteries (PA in subjects with PAH, and assessed the effects of PAH-specific therapy on indices of arterial stiffness. METHOD: Using IVUS and simultaneous right heart catheterisation, 20 pulmonary segments in 8 PAH subjects and 12 pulmonary segments in 8 controls were studied to determine their compliance, distensibility, elastic modulus and stiffness index β. PAH subjects underwent repeat IVUS examinations after 6-months of bosentan therapy. RESULTS: AT BASELINE, PAH SUBJECTS DEMONSTRATED GREATER STIFFNESS IN ALL MEASURED INDICES COMPARED TO CONTROLS: compliance (1.50±0.11×10(-2 mm(2/mmHg vs 4.49±0.43×10(-2 mm(2/mmHg, p<0.0001, distensibility (0.32±0.03%/mmHg vs 1.18±0.13%/mmHg, p<0.0001, elastic modulus (720±64 mmHg vs 198±19 mmHg, p<0.0001, and stiffness index β (15.0±1.4 vs 11.0±0.7, p = 0.046. Strong inverse exponential associations existed between mean pulmonary artery pressure and compliance (r(2 = 0.82, p<0.0001, and also between mean PAP and distensibility (r(2 = 0.79, p = 0.002. Bosentan therapy, for 6-months, was not associated with any significant changes in all indices of PA stiffness. CONCLUSION: Increased stiffness occurs in the proximal elastic PA in patients with PAH and contributes to the pathogenesis RV failure. Bosentan therapy may not be effective at improving PA stiffness.

  18. Relation of epicardial adipose tissue with arterial compliance and stiffness in patients with hypertension.

    Science.gov (United States)

    Korkmaz, Levent; Cirakoglu, Omer Faruk; Ağaç, Mustafa Tarik; Erkan, Hakan; Korkmaz, Ayca Ata; Acar, Zeydin; Kul, Selim; Hatem, Engin; Çelik, Şükrü

    2014-09-01

    The main aim of the present study was to investigate the association between epicardial adipose tissue (EAT) and arterial function in patients with asymptomatic hypertension. Patients with hypertension (n = 155) were enrolled consecutively. Patients with decreased arterial compliance (AC) and increased cardioankle vascular index (CAVI) had higher EAT values compared with those with normal AC and CAVI (6.23 ± 1.67 vs 4.91 ± 1.40, P arterial function in patients with asymptomatic hypertension. The link between EAT and arterial stiffness deserves further investigation.

  19. Finite difference solutions to shocked acoustic waves

    Science.gov (United States)

    Walkington, N. J.; Eversman, W.

    1983-01-01

    The MacCormack, Lambda and split flux finite differencing schemes are used to solve a one dimensional acoustics problem. Two duct configurations were considered, a uniform duct and a converging-diverging nozzle. Asymptotic solutions for these two ducts are compared with the numerical solutions. When the acoustic amplitude and frequency are sufficiently high the acoustic signal shocks. This condition leads to a deterioration of the numerical solutions since viscous terms may be required if the shock is to be resolved. A continuous uniform duct solution is considered to demonstrate how the viscous terms modify the solution. These results are then compared with a shocked solution with and without viscous terms. Generally it is found that the most accurate solutions are those obtained using the minimum possible viscosity coefficients. All of the schemes considered give results accurate enough for acoustic power calculations with no one scheme performing significantly better than the others.

  20. Stent-induced coronary artery stenosis characterized by multimodal nonlinear optical microscopy

    Science.gov (United States)

    Wang, Han-Wei; Simianu, Vlad; Locker, Mattew J.; Cheng, Ji-Xin; Sturek, Michael

    2011-02-01

    We demonstrate for the first time the applicability of multimodal nonlinear optical (NLO) microscopy to the interrogation of stented coronary arteries under different diet and stent deployment conditions. Bare metal stents and Taxus drug-eluting stents (DES) were placed in coronary arteries of Ossabaw pigs of control and atherogenic diet groups. Multimodal NLO imaging was performed to inspect changes in arterial structures and compositions after stenting. Sum frequency generation, one of the multimodalities, was used for the quantitative analysis of collagen content in the peristent and in-stent artery segments of both pig groups. Atherogenic diet increased lipid and collagen in peristent segments. In-stent segments showed decreased collagen expression in neointima compared to media. Deployment of DES in atheromatous arteries inhibited collagen expression in the arterial media.

  1. Long-term results of interventional treatment of large unresectable hepatocellular carcinoma (HCC): significant survival benefit from combined transcatheter arterial chemoembolization (TACE) and percutaneous ethanol injection (PEI) compared to TACE monotherapy; Langzeitergebnisse der interventionellen Therapie von grossen, inoperablen hepatozellulaeren Karzinomen (HCC): signifikanter Ueberlebensvorteil von transarterieller Chemoembolisation (TACE) und perkutaner Ethanolinjektion (PEI) gegenueber der TACE-Monotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Lubienski, A.; Bitsch, R.G.; Grenacher, L.; Kauffmann, G.W. [Radiologische Universitaetsklinik Heidelberg, Abt. Radiodiagnostik, Heidelberg (Germany); Schemmer, P. [Chirurgische Universitaetsklinik Heidelberg (Germany); Duex, M. [Radiologisches Zentralinstitut Krankenhaus Nordwest Frankfurt (Germany)

    2004-12-01

    Purpose: A retrospective analysis of long-term efficacy of combined transcatheter arterial chemoembolization (TACE) and percutaneous ethanol injection (PEI) and TACE monotherapy was conducted in patients with large, non-resectable hepatocellular carcinoma (HCC). Methods and Materials: Fifty patients with large, unresectable HCC lesions underwent selective TACE. Liver cirrhosis was present in 42 patients, due to alcohol abuse (n = 22) and viral infection (n = 17). In three patients, the underlying cause for liver cirrhosis remained unclear. Child A cirrhosis was found in 22 and Child B cirrhosis in 20 patients. Repeated and combined TACE and PEI were performed in 22 patients and repeated TACE monotherapy was performed in 28 patients. Survival and complication rates were determined and compared. Results: The 6-, 12-, 24- and 36-month survival rates were 61%, 21%, 4%, and 4% for TACE monotherapy and 77%, 55%, 39% and 22% for combined TACE and PEI (Kaplan-Meier method). The kind of treatment significantly affected the survival rate (p=0.002 log-rank test). Severe side effects were present in two patients of the monotherapy group and in three patients of the combination therapy group. (orig.)

  2. Infinite Possibilities for the Finite Element.

    Science.gov (United States)

    Finlayson, Bruce A.

    1981-01-01

    Describes the uses of finite element methods in solving problems of heat transfer, fluid flow, etc. Suggests that engineers should know the general concepts and be able to apply the principles of finite element methods. (Author/WB)

  3. Elements with Square Roots in Finite Groups

    Institute of Scientific and Technical Information of China (English)

    M.S. Lucido; M.R. Pournaki

    2005-01-01

    In this paper, we study the probability that a randomly chosen element in a finite group has a square root, in particular the simple groups of Lie type of rank 1, the sporadic finite simple groups and the alternating groups.

  4. Conforming finite elements with embedded strong discontinuities

    NARCIS (Netherlands)

    Dias-da-Costa, D.; Alfaiate, J.; Sluys, L.J.; Areias, P.; Fernandes, C.; Julio, E.

    2012-01-01

    The possibility of embedding strong discontinuities into finite elements allowed the simulation of different problems, namely, brickwork masonry fracture, dynamic fracture, failure in finite strain problems and simulation of reinforcement concrete members. However, despite the significant contributi

  5. Arterial spin labeling in patients with chic cerebral artery steno-occlusive disease - Correlation with {sup 15}O-PET

    Energy Technology Data Exchange (ETDEWEB)

    Kamano, Hironori; Yoshiura, Takashi; Hiwatashi, Akio; Abe, Koichiro; Yamashita, Koji; Honda, Hiroshi [Dept. of Clinical Radiology, Graduate School of Medical Sciences, Kyushu Univ., Fukuoka (Japan)], e-mail: tsu@radiol.med.kyushu-u.ac.jp; Togao, Osamu [Dept. of Molecular Imaging and Diagnosis, Graduate School of Medical Sciences, Kyushu Univ., Fukuoka (Japan)

    2013-02-15

    Background: Heterogeneity of arterial transit time due to cerebral artery steno-occlusive lesions hampers accurate regional cerebral blood flow measurement by arterial spin labeling (ASL). Purpose: To assess the feasibility of regional cerebral blood flow measurement by ASL with multiple-delay time sampling in patients with steno-occlusive diseases by comparing with positron emission tomography (PET), and to determine whether regional arterial transit time measured by this ASL technique is correlated with regional mean transit time, a PET index of perfusion pressure. Material and Methods: Sixteen patients with steno-occlusive diseases received both ASL and {sup 15}O-PET. The mean regional cerebral blood flow measured by ASL and PET, regional arterial transit time by ASL, and regional mean transit time by PET were obtained by a region-of-interest analysis. Correlation between regional cerebral blood flow by ASL and that by PET, and correlation between regional arterial transit time by ASL and regional mean transit time by PET were tested using Pearson's correlation coefficient for both absolute and relative values. A multivariate regression analysis was performed to test whether regional arterial transit time by ASL was a significant contributor in modeling regional mean transit time by PET after controlling the effect of regional cerebral blood flow by ASL. Results: A significant positive correlation was found between regional cerebral blood flow by ASL and that by PET for both absolute (r = 0.520, P < 0.0001) and relative (r = 0.691, P < 0.0001) values. A significant positive correlation was found between regional arterial transit time by ASL and regional mean transit time by PET both for absolute (r = 0.369, P = 0.0002) and relative (r = 0.443, P < 0.0001) values. The regression analysis revealed that regional arterial transit time by ASL was a significant contributor in modeling regional mean transit time by PET after controlling regional cerebral blood flow by

  6. Gender-related difference in arterial elastance during exercise in patients with hypertension.

    Science.gov (United States)

    Park, Sungha; Ha, Jong-Won; Shim, Chi Young; Choi, Eui-Young; Kim, Jin-Mi; Ahn, Jeong-Ah; Lee, Se-Wha; Rim, Se-Joong; Chung, Namsik

    2008-04-01

    Exercise intolerance and heart failure with preserved ejection fraction are common in females. Recently, arterial stiffness has been suggested to be a significant contributor in the development of heart failure. How gender difference affects arterial stiffening and its response to exercise is not well known. We hypothesized that arterial elastance index during exercise would be more abnormal in females with hypertension than males. Arterial elastance index was estimated as arterial end systolic pressure/stroke volume controlled for body surface area and was measured at rest and during graded supine bicycle exercise (25 watts, 3-minute increments) in 298 patients with hypertension (149 males; 149 females; mean age, 59). The subjects were divided into 2 groups by gender. Exercise duration was significantly shorter in females compared to males (692+/-222 versus 483+/-128 seconds, Parterial elastance index at baseline was significantly higher in males, the magnitude of increase was steeper in females with the magnitude of change at 75 W of exercise being significantly higher in females compared to males (0.69+/-0.83 versus 0.43+/-0.69, P=0.018). Arterial elastance index at each stage of exercise up to 75 W was independently associated with decreased exercise duration. In conclusion, despite lower arterial elastance index at rest, the increase during exercise was steeper in women with hypertension, suggesting a gender-related difference in dynamic arterial stiffness. The arterial elastance index during exercise was significantly associated with exercise duration in patients with hypertension.

  7. Selective Smoothed Finite Element Method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The paper examines three selective schemes for the smoothed finite element method (SFEM) which was formulated by incorporating a cell-wise strain smoothing operation into the standard compatible finite element method (FEM). These selective SFEM schemes were formulated based on three selective integration FEM schemes with similar properties found between the number of smoothing cells in the SFEM and the number of Gaussian integration points in the FEM. Both scheme 1 and scheme 2 are free of nearly incompressible locking, but scheme 2 is more general and gives better results than scheme 1. In addition, scheme 2 can be applied to anisotropic and nonlinear situations, while scheme 1 can only be applied to isotropic and linear situations. Scheme 3 is free of shear locking. This scheme can be applied to plate and shell problems. Results of the numerical study show that the selective SFEM schemes give more accurate results than the FEM schemes.

  8. Representation theory of finite monoids

    CERN Document Server

    Steinberg, Benjamin

    2016-01-01

    This first text on the subject provides a comprehensive introduction to the representation theory of finite monoids. Carefully worked examples and exercises provide the bells and whistles for graduate accessibility, bringing a broad range of advanced readers to the forefront of research in the area. Highlights of the text include applications to probability theory, symbolic dynamics, and automata theory. Comfort with module theory, a familiarity with ordinary group representation theory, and the basics of Wedderburn theory, are prerequisites for advanced graduate level study. Researchers in algebra, algebraic combinatorics, automata theory, and probability theory, will find this text enriching with its thorough presentation of applications of the theory to these fields. Prior knowledge of semigroup theory is not expected for the diverse readership that may benefit from this exposition. The approach taken in this book is highly module-theoretic and follows the modern flavor of the theory of finite dimensional ...

  9. Quantum Computing over Finite Fields

    CERN Document Server

    James, Roshan P; Sabry, Amr

    2011-01-01

    In recent work, Benjamin Schumacher and Michael~D. Westmoreland investigate a version of quantum mechanics which they call "modal quantum theory" but which we prefer to call "discrete quantum theory". This theory is obtained by instantiating the mathematical framework of Hilbert spaces with a finite field instead of the field of complex numbers. This instantiation collapses much the structure of actual quantum mechanics but retains several of its distinguishing characteristics including the notions of superposition, interference, and entanglement. Furthermore, discrete quantum theory excludes local hidden variable models, has a no-cloning theorem, and can express natural counterparts of quantum information protocols such as superdense coding and teleportation. Our first result is to distill a model of discrete quantum computing from this quantum theory. The model is expressed using a monadic metalanguage built on top of a universal reversible language for finite computations, and hence is directly implementab...

  10. Automation of finite element methods

    CERN Document Server

    Korelc, Jože

    2016-01-01

    New finite elements are needed as well in research as in industry environments for the development of virtual prediction techniques. The design and implementation of novel finite elements for specific purposes is a tedious and time consuming task, especially for nonlinear formulations. The automation of this process can help to speed up this process considerably since the generation of the final computer code can be accelerated by order of several magnitudes. This book provides the reader with the required knowledge needed to employ modern automatic tools like AceGen within solid mechanics in a successful way. It covers the range from the theoretical background, algorithmic treatments to many different applications. The book is written for advanced students in the engineering field and for researchers in educational and industrial environments.

  11. Factorization Properties of Finite Spaces

    CERN Document Server

    Simkhovich, B; Zak, J; 10.1088/1751-8113/43/4/045301

    2010-01-01

    In 1960 Schwinger [J. Schwinger, Proc.Natl.Acad.Sci. 46 (1960) 570- 579] proposed the algorithm for factorization of unitary operators in the finite M dimensional Hilbert space according to a coprime decomposition of M. Using a special permutation operator A we generalize the Schwinger factorization to every decomposition of M. We obtain the factorized pairs of unitary operators and show that they obey the same commutation relations as Schwinger's. We apply the new factorization to two problems. First, we show how to generate two kq-like mutually unbiased bases for any composite dimension. Then, using a Harper-like Hamiltonian model in the finite dimension M = M1M2, we show how to design a physical system with M1 energy levels, each having degeneracy M2.

  12. DOLFIN: Automated Finite Element Computing

    CERN Document Server

    Logg, Anders; 10.1145/1731022.1731030

    2011-01-01

    We describe here a library aimed at automating the solution of partial differential equations using the finite element method. By employing novel techniques for automated code generation, the library combines a high level of expressiveness with efficient computation. Finite element variational forms may be expressed in near mathematical notation, from which low-level code is automatically generated, compiled and seamlessly integrated with efficient implementations of computational meshes and high-performance linear algebra. Easy-to-use object-oriented interfaces to the library are provided in the form of a C++ library and a Python module. This paper discusses the mathematical abstractions and methods used in the design of the library and its implementation. A number of examples are presented to demonstrate the use of the library in application code.

  13. Recurrent ischemia resulting from left internal mammary artery-to-pulmonary artery fistula.

    Science.gov (United States)

    Madu, E C; Hanumanthu, S K; Kim, C; Prudoff, A

    2001-03-01

    This report describes a case series of recurrent ischemia after coronary artery bypass grafting resulting from left internal mammary artery-to-pulmonary artery fistula. An angiographic demonstration of this fistula is presented.

  14. Finite Metric Spaces of Strictly Negative Type

    DEFF Research Database (Denmark)

    Hjorth, Poul; Lisonek, P.; Markvorsen, Steen

    1998-01-01

    We prove that, if a finite metric space is of strictly negative type, then its transfinite diameter is uniquely realized by the infinite extender (load vector). Finite metric spaces that have this property include all spaces on two, three, or four points, all trees, and all finite subspaces of Eu...... by Kelly, we conjecture that all finite subspaces of hyperbolic spaces are hypermetric and regular, and hence of strictly negative type. (C) 1998 Elsevier Science Inc....

  15. Flux tubes at Finite Temperature

    CERN Document Server

    Bicudo, Pedro; Cardoso, Marco

    2016-01-01

    We show the flux tubes produced by static quark-antiquark, quark-quark and quark-gluon charges at finite temperature. The sources are placed in the lattice with fundamental and adjoint Polyakov loops. We compute the square densities of the chromomagnetic and chromoelectric fields above and below the phase transition. Our results are gauge invariant and produced in pure gauge SU(3). The codes are written in CUDA and the computations are performed with GPUs.

  16. Finite Operator-Valued Frames

    OpenAIRE

    Meng, Bin

    2010-01-01

    Operator-valued frames are natural generalization of frames that have been used in quantum computing, packets encoding, etc. In this paper, we focus on developing the theory about operator-valued frames for finite Hilbert spaces. Some results concerning dilation, alternate dual, and existence of operator-valued frames are given. Then we characterize the optimal operator-valued frames under the case which one packet of data is lost in transmission. At last we construct the operator-valued fram...

  17. Finite mathematics models and applications

    CERN Document Server

    Morris, Carla C

    2015-01-01

    Features step-by-step examples based on actual data and connects fundamental mathematical modeling skills and decision making concepts to everyday applicability Featuring key linear programming, matrix, and probability concepts, Finite Mathematics: Models and Applications emphasizes cross-disciplinary applications that relate mathematics to everyday life. The book provides a unique combination of practical mathematical applications to illustrate the wide use of mathematics in fields ranging from business, economics, finance, management, operations research, and the life and social sciences.

  18. Maximal subgroups of finite groups

    Directory of Open Access Journals (Sweden)

    S. Srinivasan

    1990-01-01

    Full Text Available In finite groups maximal subgroups play a very important role. Results in the literature show that if the maximal subgroup has a very small index in the whole group then it influences the structure of the group itself. In this paper we study the case when the index of the maximal subgroups of the groups have a special type of relation with the Fitting subgroup of the group.

  19. Commutators with Finite Spectrum Ⅱ

    Institute of Scientific and Technical Information of China (English)

    Nadia BOUDI

    2009-01-01

    The purpose of this paper is to study derivations d, d' defined on a Banach algebra A such that the spectrum σ([dx, d'x]) is finite for all x ∈ A. In particular we show that if the algebra is semisimple, then there exists an element a in the socle of A such that [d, d'] is the inner derivation implemented by a.

  20. Simulated lipoprotein transport in the wall of branched arteries.

    Science.gov (United States)

    Darbeau, M Z; Lutz, R J; Collins, W E

    2000-01-01

    Study of arterial blood flow dynamics improves our understanding of the development of cardiovascular diseases such as atherosclerosis. The transport and accumulation of macromolecules in the arterial wall can be influenced by local fluid mechanics. We used numeric simulations to investigate such transport in a T-junction model. Presumably an in vitro experiment would consist of gel segments inserted in the walls of a mechanical flow T-junction model near branch points where separation and recirculation zones are expected. The transport of low density lipoprotein (LDL) was investigated theoretically at these sites in a two dimensional numeric T-branch model. In the numeric model, the hydraulic conductivity of the porous gel wall segments was varied for a fixed species diffusivity to provide simulations with wall transmural Peclet numbers ranging from 0.3 to 30. Steady state flow patterns in the lumen of the two dimensional T-branch were simulated at Reynolds numbers of 250 and 500, using the software package FIDAP 7.61 to implement the finite element method. The simulations demonstrated that wall Peclet numbers greater than 1.0 were needed to achieve species concentration gradients within the wall that varied in the axial direction, thereby reflecting the influence of disturbed flow and pressure patterns in the lumen. As expected, the transmural concentration gradients were steeper when convection predominated. Blood flow in the lumen can influence the distribution of macromolecules in the arterial wall and needs to be investigated for the relevance to atherosclerosis.

  1. Differential analysis of clinical features in atherosclerotic renal artery stenosis and benign nephrosclerosis

    Institute of Scientific and Technical Information of China (English)

    郭云珊

    2006-01-01

    Objective To analyze and compare the clinical characteristics of atherosclerotic renal artery stenosis (ARAS) and benign nephrosclerosis (BN) in order to distinguish the ARAS from BN. Methods A retrospective study was performed on 82 hypertensive patients with renal injury. Patients were divided into BN and ARAS group according to renal artery doppler scanning. The

  2. [Acute extremity ischemia based on the popliteal artery aneurysm thrombosis--combined thrombolytic and surgical management].

    Science.gov (United States)

    Danek, T; Janousek, R; Havlícek, K

    2006-03-01

    Authors present their experience with combined trombolytic-surgical treatment of acute ischaemia of low extremity based on trombosis of popliteal artery aneurysm. This treatment was performed in three patients. Authors compare results of intraarterial catheter pharmacological trombolysis of infrapopliteal arteries with indirect surgical trombolysis.

  3. In-depth characterization of CGRP receptors in human intracranial arteries

    DEFF Research Database (Denmark)

    Jansen-Olesen, Inger; Jørgensen, Linda; Engel, Ulla;

    2003-01-01

    meningeal arteries. Removal of the endothelium neither changed the maximum relaxant response nor the pIC(50) values for alpha- and beta-CGRP as compared to the responses in arteries with an intact endothelium. Human alpha-CGRP-(8-37) caused a shift of h alpha- and h beta-CGRP-induced relaxations in cerebral...

  4. DETERMINATION OF AMMONIA IN EAR-LOBE CAPILLARY BLOOD IS AN ALTERNATIVE TO ARTERIAL BLOOD AMMONIA

    NARCIS (Netherlands)

    HUIZENGA, [No Value; GIPS, CH; CONN, HO; JANSEN, PLM

    1995-01-01

    Blood ammonia determination is a laboratory test to diagnose hepatic encephalopathy. Arterial blood is superior to peripheral venous blood ammonia because of ammonia metabolism in muscle. We have compared capillary with arterial whole blood ammonia as capillary sampling is an attractive alternative.

  5. First clinical experience with Celt ACD(®) : a femoral arterial puncture closure device.

    LENUS (Irish Health Repository)

    Jan, Aftab

    2013-08-01

    This prospective nonrandomized study compared the safety and efficacy of a novel arterial closure device (ACD) in common femoral artery procedures to that of the FDA submitted historical manual pressure control group, who underwent either a diagnostic angiogram (DA) or a percutaneous coronary intervention (PCI) procedure.

  6. Capsaicin- resistant arterial baroreceptors

    Directory of Open Access Journals (Sweden)

    Andresen Michael C

    2006-05-01

    Full Text Available Abstract Background Aortic baroreceptors (BRs comprise a class of cranial afferents arising from major arteries closest to the heart whose axons form the aortic depressor nerve. BRs are mechanoreceptors that are largely devoted to cardiovascular autonomic reflexes. Such cranial afferents have either lightly myelinated (A-type or non-myelinated (C-type axons and share remarkable cellular similarities to spinal primary afferent neurons. Our goal was to test whether vanilloid receptor (TRPV1 agonists, capsaicin (CAP and resiniferatoxin (RTX, altered the pressure-discharge properties of peripheral aortic BRs. Results Periaxonal application of 1 μM CAP decreased the amplitude of the C-wave in the compound action potential conducting at 0.50 but completely inhibited discharge of an irregularly discharging BR (C-type. CAP at high concentrations (10–100 μM depressed BR sensitivity in regularly discharging BRs, an effect attributed to non-specific actions. RTX (≤ 10 μM did not affect the discharge properties of regularly discharging BRs (n = 7, p > 0.18. A CAP-sensitive BR had significantly lower discharge regularity expressed as the coefficient of variation than the CAP-resistant fibers (p Conclusion We conclude that functional TRPV1 channels are present in C-type but not A-type (A-δ myelinated aortic arch BRs. CAP has nonspecific inhibitory actions that are unlikely to be related to TRV1 binding since such effects were absent with the highly specific TRPV1 agonist RTX. Thus, CAP must be used with caution at very high concentrations.

  7. Selforthogonal modules with finite injective dimension

    Institute of Scientific and Technical Information of China (English)

    黄兆泳

    2000-01-01

    The category consisting of finitely generated modules which are left orthogonal with a cotilting bimodule is shown to be functorially finite. The notion of left orthogonal dimension is introduced , and then a necessary and sufficient condition of selforthogonal modules having finite injective dimension and a characterization of cotilting modules are given.

  8. Selforthogonal modules with finite injective dimension

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The category consisting of finitely generated modules which are left orthogonal with a cotilting bimodule is shown to be functorially finite. The notion of left orthogonal dimension is introduced, and then a necessary and sufficient condition of selforthogonal modules having finite injective dimension and a characterization of cotilting modules are given.

  9. Finite Metric Spaces of Strictly negative Type

    DEFF Research Database (Denmark)

    Hjorth, Poul G.

    If a finite metric space is of strictly negative type then its transfinite diameter is uniquely realized by an infinite extent (“load vector''). Finite metric spaces that have this property include all trees, and all finite subspaces of Euclidean and Hyperbolic spaces. We prove that if the distance...

  10. FINITE RIODAN MATRIX AND RIODAN GROUP

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Riodan Matrix is a lower triangular matrix of in finite order with certainly restricted conditions.In this paper,the author defines two kinds of finite Riodan matrices which are not limited to lower triangular.Properties of group theory of the two kinds matrices are considered.Applications of the finite Riodan matrices are researched.

  11. LQR control for scalar finite and infinite platoons

    NARCIS (Netherlands)

    Curtain, R.F.; Iftime, O.V.; Zwart, H.J.; El Jai, A.; Afifi, L.; Zerrik, E.

    2009-01-01

    In this paper we compare the behaviour of the LQR solution for a finite platoon model with its infinite version. We give examples where these are similar and some where they are quite different. For the scalar case we obtain sufficient conditions for the LQR solutions to be similar by relating the T

  12. Meson Effects on the Chiral Condensate at Finite Density

    Institute of Scientific and Technical Information of China (English)

    HUANG Mei; ZHUANG Peng-Fei; ZHAO Wei-Qin

    2002-01-01

    Meson corrections on the chiral condensate up to next-to-leading order in a 1/Nc expansion at finite densityare investigated in the NJL model with explicit chiral symmetry breaking. Compared with mean-field results, the chiralphase transition is still of the first order while the properties near the critical density for chiral phase transition are foundto change significantly.

  13. Numerical Radius Inequalities for Finite Sums of Operators

    Directory of Open Access Journals (Sweden)

    Mirmostafaee Alireza Kamel

    2014-12-01

    Full Text Available In this paper, we obtain some sharp inequalities for numerical radius of finite sums of operators. Moreover, we give some applications of our result in estimation of spectral radius. We also compare our results with some known results.

  14. POWER OPTIMIZATION OF FINITE STATE MACHINE BASED ON GENETIC ALGORITHM

    Institute of Scientific and Technical Information of China (English)

    Xia Yinshui; A.E.A. Almaini; Wu Xunwei

    2003-01-01

    Using state assignment to minimize power dissipation and area for finite state ma-chines is computationally hard. Most of published results show that the reduction of switchingactivity often trades with area penalty. In this paper, a new approach is proposed. Experimentalresults show a significant reduction of switching activity without area penalty compared withprevious publications.

  15. Retinal artery occlusions in children.

    Science.gov (United States)

    Dharmasena, Aruna; Wallis, Simon

    2014-01-01

    The purpose of this study is to present a case of RAO in a 13 year old girl with a preceding history of hyperextension of the neck at her hairdressers for a long duration and use of her mobile phone handset resting it against the side of her neck presumably exerting some pressure on carotids during the same time. Materials and methods of this study was reported as case report and review of literature. A 13 year-old girl presented with the left supero-nasal scotoma due to an inferior temporal branch retinal artery occlusion (BRAO). She underwent extensive investigations and no underlying cause was discovered. She gave a history of cervical extension over a long period of time while having the hair coloured twice in the preceding week. She also mentioned that she was using her mobile phone more or less continuously during both these occasions keeping it against her neck. Given the above history it is possible that the pressure on the ipsilateral carotid arteries or the prolong neck extension may have been responsible for the formation of a platelet embolus resulting in the BRAO. In conclusion, although cerebro-vascular accidents due to 'beauty parlor stroke syndrome' (JAMA 269:2085-2086, 1993) have been reported previously it has not been reported in children to our knowledge. On the other hand, 'beauty parlor stroke syndrome' occurs due to a dissection of the vertebral arteries or due to mechanical compression of the vertebral arteries during the prolonged hyperextension of the neck. The central retinal artery originates from the internal carotid circulation and it is highly unlikely for an embolus to enter the retinal circulation from the vertebral arteries. Therefore, the authors favour the possibility that the compulsive use of a mobile phone exerting pressure on the carotid arteries for a long time may have led to the formation of an embolus and subsequent RAO in this case.

  16. Generalized multiscale finite element methods: Oversampling strategies

    KAUST Repository

    Efendiev, Yalchin R.

    2014-01-01

    In this paper, we propose oversampling strategies in the generalized multiscale finite element method (GMsFEM) framework. The GMsFEM, which has been recently introduced in Efendiev et al. (2013b) [Generalized Multiscale Finite Element Methods, J. Comput. Phys., vol. 251, pp. 116-135, 2013], allows solving multiscale parameter-dependent problems at a reduced computational cost by constructing a reduced-order representation of the solution on a coarse grid. The main idea of the method consists of (1) the construction of snapshot space, (2) the construction of the offline space, and (3) construction of the online space (the latter for parameter-dependent problems). In Efendiev et al. (2013b) [Generalized Multiscale Finite Element Methods, J. Comput. Phys., vol. 251, pp. 116-135, 2013], it was shown that the GMsFEM provides a flexible tool to solve multiscale problems with a complex input space by generating appropriate snapshot, offline, and online spaces. In this paper, we develop oversampling techniques to be used in this context (see Hou and Wu (1997) where oversampling is introduced for multiscale finite element methods). It is known (see Hou and Wu (1997)) that the oversampling can improve the accuracy of multiscale methods. In particular, the oversampling technique uses larger regions (larger than the target coarse block) in constructing local basis functions. Our motivation stems from the analysis presented in this paper, which shows that when using oversampling techniques in the construction of the snapshot space and offline space, GMsFEM will converge independent of small scales and high contrast under certain assumptions. We consider the use of a multiple eigenvalue problems to improve the convergence and discuss their relation to single spectral problems that use oversampled regions. The oversampling procedures proposed in this paper differ from those in Hou and Wu (1997). In particular, the oversampling domains are partially used in constructing local

  17. PERFORMANCE MODELING AND ANALYSIS OF BLOOD FLOW IN ELASTIC ARTERIES

    Institute of Scientific and Technical Information of China (English)

    Anil Kumar; C.L. Varshney; G.C. Sharma

    2005-01-01

    Two different non-Newtonian models for blood flow are considered, first a simple power law model displaying shear thinning viscosity, and second a generalized Maxwell model displaying both shear thinning viscosity and oscillating flow viscous-elasticity. These models are used along with a Newtonian model to study sinusoidal flow of blood in rigid and elastic straight arteries in the presence of magnetic field. The elasticity of blood does not appear to influence its flow behavior under physiological conditions in the large arteries,purely viscous shear thinning model should be quite realistic for simulating blood flow under these conditions. On using the power law model with high shear rate for sinusoidal flow simulation in elastic arteries, the mean and amplitude of the flow rate were found to be lower for a power law fluid compared to Newtonian fluid for the same pressure gradient. The governing equations have been solved by Crank-Niclson scheme. The results are interpreted in the context of blood in the elastic arteries keeping the magnetic effects in view. For physiological flow simulation in the aorta, an increase in mean wall shear stress, but a reduction in peak wall shear stress were observed for power law model compared to a Newtonian fluid model for matched flow rate wave form. Blood flow in the presence of transverse magnetic field in an elastic artery is investigated and the influence of factors such as morphology and surface irregularity is evaluated.

  18. Impeller deflection and modal finite element analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Nathan A.

    2013-10-01

    Deflections of an impeller due to centripetal forces are calculated using finite element analysis. The lateral, or out of plane, deflections are an important design consideration for this particular impeller because it incorporates an air bearing with critical gap tolerances. The target gap distance is approximately 10 microns at a rotational velocity of 2500 rpm. The centripetal forces acting on the impeller cause it deflect in a concave fashion, decreasing the initial gap distance as a function of radial position. This deflection is characterized for a previous and updated impeller design for comparative purposes. The impact of design options such as material selection, geometry dimensions, and operating rotational velocity are also explored, followed by a sensitivity study with these parameters bounded by specific design values. A modal analysis is also performed to calculate the impeller's natural frequencies which are desired to be avoided during operation. The finite element modeling techniques continue to be exercised by the impeller design team to address specific questions and evaluate conceptual designs, some of which are included in the Appendix.

  19. The representation of boundary currents in a finite element shallow water model

    CERN Document Server

    Düben, Peter D

    2015-01-01

    We evaluate the influence of local resolution, eddy viscosity, coastline structure, and boundary conditions on the numerical representation of boundary currents in a finite element shallow-water model. The use of finite element discretization methods offers a higher flexibility compared to finite difference and finite volume methods, that are mainly used in previous publications. This is true for the geometry of the coast lines and for the realization of boundary conditions. For our investigations we simulate steady separation of western boundary currents from idealized and realistic coast lines. The use of grid refinement allows a detailed investigation of boundary separation at reasonable numerical cost.

  20. A case report: accessory right renal artery

    Directory of Open Access Journals (Sweden)

    Patasi B

    2009-10-01

    Full Text Available Anatomical variations in the origin of the arteries in the abdominal area are very common. The arteries that show frequent variations include the celiac trunk, renal and gonadal arteries. During a routine dissection of a male cadaver, one main and one inferior accessory renal artery were found in the abdominal region. We discovered that the inferior accessory renal artery that originated from the right anterolateral aspect of abdominal aorta was running into the lower pole of the right kidney. The origin of the main right renal artery and the inferior accessory right renal artery were 19.8 mm and 53 mm below the superior mesenteric artery, respectively. The inferior accessory right renal artery ran directly into the inferior pole of the right kidney, in the area where the accessory right renal vein was leaving the right kidney. These anatomical variations and anomalies are important to know before any therapeutic or diagnostic procedures are performed in the abdominal area.