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

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    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. Tactile Distinction of an Artery and a Tumor in a Soft Tissue by Finite Element Method

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    Ali A.  Mehrizi

    2008-01-01

    Full Text Available Tactile detection of a tumor and an artery in a tissue and distinction of a healthy artery from a stenotic artery, using finite element method, are presented. Four 2D models of tissue have been created: tissue itself, tissue including a tumor (TIT, tissue including a healthy artery (TIHA, and tissue including a stenotic artery (TISA. After solving four models with similar boundary conditions and loadings, the 2D tactile mappings and stress graphs for upper nodes of models, which have key importance for transferring tactile data, were explored. Then, by comparing these results, if the stress values of nodes were constant and equal, tissue is unlikely to have any tumor or artery embedded. Otherwise, if the stress graph included a peak, the tissue had a tumor or an artery. Additionally, it was observed that the stress graph of tissue including an artery is time-dependent in comparison with the tissue including a tumor. Further, it was concluded that a stenotic artery had larger stress peak than a healthy artery.

  3. Finite cell method compared to h-version finite element method for elasto-plastic problems

    Institute of Scientific and Technical Information of China (English)

    A.ABEDIAN; J.PARVIZIAN; A.D USTER; E.RANK

    2014-01-01

    The finite cell method (FCM) combines the high-order finite element method (FEM) with the fictitious domain approach for the purpose of simple meshing. In the present study, the FCM is used to the Prandtl-Reuss flow theory of plasticity, and the results are compared with the h-version finite element method (h-FEM). The numerical results show that the FCM is more efficient compared to the h-FEM for elasto-plastic problems, although the mesh does not conform to the boundary. It is also demonstrated that the FCM performs well for elasto-plastic loading and unloading.

  4. 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.

  5. 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

  6. 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.

  7. 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)

  8. 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.

  9. Iatrogenic and noniatrogenic arterial trauma: a comparative study.

    Science.gov (United States)

    Lazarides, M K; Arvanitis, D P; Liatas, A C; Dayantas, J N

    1991-01-01

    During a 6-year period 22 patients were operated on because of iatrogenic arterial trauma (group A) and 43 sustained noniatrogenic arterial injury (group B). The group A injuries were caused by various arterial catheterization procedures for angiography or cardiac investigation (55%) or surgical interventions (45%). Haemorrhage was more common in group B than in group A (p less than 0.001). The mortality rate did not differ significantly between the groups (14% vs. 9%). Permanent disability was more common in group B (p less than 0.05), due mainly to higher incidence of associated venous, neural, skeletal or visceral injuries. Bypass operations tended to be more often performed in group B than in group A, but the difference was not statistically significant. Retrospective assessment of the appropriateness of technique, made separately by two vascular surgeons, revealed instances of potentially avoidable iatrogenic arterial injury. The rising incidence of iatrogenic arterial trauma may therefore be considered 'reducible'. PMID:1675876

  10. 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.

  11. Comparative analysis of finite field-dependent BRST transformations

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    Moshin, Pavel Yu

    2016-01-01

    We present a review of our recent study (A. Reshetnyak, IJMPA 29 (2014) 1450128; P. Moshin, A. Reshetnyak, Nucl. Phys. B 888 (2014) 92; Phys. Lett B 739 (2014) 110; IJMPA 29 (2014) 1450159; IJMPA 30 (2015) 1550021; [arxiv:1506.04660 [hep-th]), in which the concept of finite field-dependent BRST and BRST-antiBRST transformations for gauge theories was introduced, and their properties investigated. An algorithm of exact calculation for the Jacobian of a respective change of variables in the path integral is presented. Applications to the Yang--Mills theory and Standard Model, in view of infra-red (Gribov) peculiarities, are discussed.

  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.

    Science.gov (United States)

    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.

    Science.gov (United States)

    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. COMPARATIVE EVALUATION OF COLOR DOPPLER AND CONVENTIONAL DIGITAL SUBTRACTION ANGIOGRAPHY IN INFRA GENICULAR ARTERIAL DISEASE: A PROSPECTIVE COMPARATIVE STUDY

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    Akshara

    2015-03-01

    Full Text Available Patient suffering from infragenicular peripheral arterial occlusive disease is not an uncommon clinical scenario. In our setup Buergers Disease and Atherosclerotic disease are the most common cause of arterial insufficiency, particularly in middle aged smokers of low socioeconomic status apart from vasculitis, th romboembolism and trauma. Color Doppler (CD is a good modality for assessment of supragenicular arterial system, however infragenicular arteries are many times cannot be examined properly because of their deeper position. Digital Subtraction Arteriography ( DSA is a better modality in this situation . The aim of this study is to compare color doppler and conventionional digital subtraction arteriography in patients of infragenicular arterial disease. This prospective study was designed in the department of Radiodiagnosis G.R. Medical College Gwalior Madhya - Pradesh, India . 50 patients of lower limb ischemia formed the subjects and their affected lower limbs were evaluated by CD (COLOR DOPPLER and DSA (Digital Subtraction Arteriography, for localization and grading of lesions in the arteries, into normal, insignificant stenosis, significant stenosis and occlusion. The results were analyzed in a blind fashion in a total of 150 vascular segments. Results were analyzed by two way contingency tables and kappa statistics. In our study we observed that in the infragenicular arterial system disease, color doppler had a Sensitivity = 83%, Specificity = 92%, PPV = 66%, NPV = 96% Therefore it can be concluded that a normal color flow and spectral waveform in Color Doppler examination of inferiorgenicular arteries excludes the need of arteriography. However DSA is definitely helpful in patient where abnormal/absent color flow and/or spectral wave form is seen because of lower PPV (66% Color Doppler.

  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. Modeling blood flow circulation in intracranial arterial networks: a comparative 3D/1D simulation study.

    Science.gov (United States)

    Grinberg, L; Cheever, E; Anor, T; Madsen, J R; Karniadakis, G E

    2011-01-01

    We compare results from numerical simulations of pulsatile blood flow in two patient-specific intracranial arterial networks using one-dimensional (1D) and three-dimensional (3D) models. Specifically, we focus on the pressure and flowrate distribution at different segments of the network computed by the two models. Results obtained with 1D and 3D models with rigid walls show good agreement in massflow distribution at tens of arterial junctions and also in pressure drop along the arteries. The 3D simulations with the rigid walls predict higher amplitude of the flowrate and pressure temporal oscillations than the 1D simulations with compliant walls at various segments even for small time-variations in the arterial cross-sectional areas. Sensitivity of the flow and pressure with respect to variation in the elasticity parameters is investigated with the 1D model. PMID:20661645

  19. Automatic Generation of Individual Finite-Element Models for Computational Fluid Dynamics and Computational Structure Mechanics Simulations in the Arteries

    Science.gov (United States)

    Hazer, D.; Schmidt, E.; Unterhinninghofen, R.; Richter, G. M.; Dillmann, R.

    2009-08-01

    Abnormal hemodynamics and biomechanics of blood flow and vessel wall conditions in the arteries may result in severe cardiovascular diseases. Cardiovascular diseases result from complex flow pattern and fatigue of the vessel wall and are prevalent causes leading to high mortality each year. Computational Fluid Dynamics (CFD), Computational Structure Mechanics (CSM) and Fluid Structure Interaction (FSI) have become efficient tools in modeling the individual hemodynamics and biomechanics as well as their interaction in the human arteries. The computations allow non-invasively simulating patient-specific physical parameters of the blood flow and the vessel wall needed for an efficient minimally invasive treatment. The numerical simulations are based on the Finite Element Method (FEM) and require exact and individual mesh models to be provided. In the present study, we developed a numerical tool to automatically generate complex patient-specific Finite Element (FE) mesh models from image-based geometries of healthy and diseased vessels. The mesh generation is optimized based on the integration of mesh control functions for curvature, boundary layers and mesh distribution inside the computational domain. The needed mesh parameters are acquired from a computational grid analysis which ensures mesh-independent and stable simulations. Further, the generated models include appropriate FE sets necessary for the definition of individual boundary conditions, required to solve the system of nonlinear partial differential equations governed by the fluid and solid domains. Based on the results, we have performed computational blood flow and vessel wall simulations in patient-specific aortic models providing a physical insight into the pathological vessel parameters. Automatic mesh generation with individual awareness in terms of geometry and conditions is a prerequisite for performing fast, accurate and realistic FEM-based computations of hemodynamics and biomechanics in the

  20. COMPARATIVE EVALUATION OF COLOR DOPPLER AND CONVENTIONAL DIGITAL SUBSTRACTION ANGIOGRAGRAPHY IN SUPRGENICULAR ARTERIAL DISEASE: A PROSPECIVE COMPARATIVE STUDY

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    Sikarwar

    2014-02-01

    Full Text Available AIMS AND OBJECTIVES : To evaluate and correlate the findings of CD with arteriography as the gold standard , in PAOD of the lower extremities in supra - genicular part and to define whether color Doppler , is an alternative or an adjunct to DSA. S ETTINGS AND DESIGN : This prospective study was designed in the department of Radiodiagnosis G.R. Medical college Gwalior Madhya - Pradesh. + Patients were subjected to CFD scan followed by arteriography , to evaluate the lower limb arteries. MATERIALS AND METHODS : Those Patients who were due for DSA were subjected to CD scan followed by arteriography , to evaluate the lower limb arteries.50 patients of PAOD formed the subjects and their affected lower limbs evaluated by CD and arteriography , for localization and grading of lesion in the arteries , into normal/insignificant stenosis , significant stenosis and occlusion. The results were analyzed in a blind fashion in a total of 58 limbs comprising of 300 vascular segments. Statistical Analysis : Results were analyzed by two way contingency tables , using calculator , and SSP software . RESULTS : There was good stati stical agreement and sensitivity of CD was 91%specificity was 97% , PPV was 87% , and NPV was 98%in supragenicular part. CONCLUSION : The agreement between CD and DSA was generally good , irrespective of the severity of ischemia . CD performed well compared wit h DSA. Hence color Doppler can be an alternative to DSA in diagnosing peripheral arterial occlusive diseases in supragenicular part of lower limb arteries.

  1. 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...

  2. 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

  3. 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...

  4. Transcutaneous monitoring of blood gases: is it comparable with arterialized earlobe sampling?

    Science.gov (United States)

    Dawson, S; Cave, C; Pavord, I; Potter, J F

    1998-03-01

    Researchers are increasingly looking for reliable non-invasive methods of assessing blood gas concentrations, and several new techniques have recently become available. Values derived using arterialized earlobe samples have been found to be comparable with conventional arterial samples, and recent studies have compared transcutaneous blood gas analysis with the traditional arterial samples and found a reasonable level of agreement in particular for the partial pressure of carbon dioxide. There are no data comparing oxygen and carbon dioxide partial pressures (pO2, pCO2) derived from arterialized samples with one of the newer transcutaneous techniques. We therefore simultaneously studied arterialized earlobe blood gas samples and values for pO2 and pCO2 obtained by a transcutaneous monitor (TINA, Radiometer, Copenhagen) in 26 subjects with varying blood gas values. There was a close agreement between the two methods for assessment of pCO2 [mean difference (95% C.I.) between transcutaneous and earlobe values 0.25 kPa (-0.004, 0.5 kPa)], but not for pO2 [1.71 kPa (0.35, 3.07 kPa)]. Similarly, the limits of agreement were narrow for pCO2 compared to those for pO2 (-0.98, 1.47 kPa and -6.44, 3.02 kPa respectively). We conclude that transcutaneous measurement of pCO2 using the TINA is acceptable in the research setting, whereas assessment of pO2 cannot reliably be made using this technique. PMID:9692127

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

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    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.

  6. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. COMPARATIVE EVALUATION OF HEMODYNAMIC CHARACTERISTICS IN PATIENTS WITH RHEUMATOID ARTHRITIS AND ARTERIAL HYPERTENSION

    Directory of Open Access Journals (Sweden)

    Y. E. Teregulov

    2015-09-01

    Full Text Available Aim. To study the peculiarities of hemodynamic disorders in patients with rheumatoid arthritis (RA and arterial hypertension (HT, and in patients with hypertension but without RA using the integral indicators of arterial stiffness.Material and methods. The study included 106 RA patients (group 1, among them 83 (78% women and 23 (22% men, mean age 45.3±10.3 years. The group of comparison (group 2 included 63 patients (22 (35% women and 41 (65% men, mean age 47.9±12.8 years with HT stages 1-3. The control group (group 3 consisted of 32 healthy volunteers: 19 women and 13 men, mean age 24.7±5.34 years. All patients underwent ECG and echocardiography. The model of cardiovascular system was used to calculate the modulus of volume elasticity (MVE, mean arterial blood pressure (BP and total peripheral vascular resistance (TPR; stroke volume and cardiac output were measured using echocardiography.Results. Significant differences in the parameters of BP, arterial stiffness and TPR were identified in patients with RA and HT as compared with the patients of the control group. Arterial stiffness in RA patients with HT, as well as without it, was significantly higher and TPR was lower than in hypertensive patients. RA patients with HT were older and had significantly higher values of cardiac output than those without HT. In RA patients hyperkinetic type of hemodynamics was observed in 53.8% of the cases, eukinetic - in 34.9%, hypokinetic - in 11.3%. Hypertensive patients had same types of hemodynamics in 3.2%, 61.9%, and 34.9%, respectively. In healthy people hyperkinetic type was observed in 22.9% of the cases, eukinetic - in 65.6%, hypokinetic - in 12.5%.Conclusions. RA patients as compared with healthy people had significantly higher arterial stiffness indices regardless of BP. At that, hyperkinetic type of hemodynamics prevailed in RA patients, while in hypertensive patients and healthy people - the eukinetic one. Increased stroke volume and cardiac

  9. [Comparative study of two methods of arterialization of foot veins in ischemic crisis].

    Science.gov (United States)

    Lengua, F; Nuss, J M; Buffet, J M; Lechner, R

    1993-01-01

    Between February 1974 and December 1991, a total of 28 arterializations of the venous network of foot were performed in patients with stage IIIB or IV arteriopathies presenting disseminated femoropopliteal and more distal lesions excluding revascularization by conventional arterial shunt operations. Two groups of patients could be distinguished. The first group, of 8 patients, underwent arterialization by shunt operation with end to end fistula at the distal part of leg and return blood emptying at the dorsal surface of foot (3 cases). The procedure was successful in 50% of cases after a mean follow up of 76 months. The intervention in the second group, of 20 patients, was by end to side fistula of foot after preoperative countercurrent phlebography and the use of a material better adapted for the destruction of the valves. Results were evaluated as successful in 70% of cases at 31 month follow up. After spontaneous closure of the fistula, the collateral circulation provoked by it was sufficient to conserve the acquired benefit. No deaths or cases of cardiac overload were reported as a result of the intervention. Comparative analysis of results showed that the use of the second procedure allowed amputation to be avoided in more than 2/3rds of cases, provided relief from pain, provoked healing of necrosed areas and permitted renewal of walking. The results of this study have demonstrated that venous arterialization of the foot by this method represents an interesting alternative in the saving of a limb destined for amputation. PMID:8496251

  10. [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.

  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

    Directory of Open Access Journals (Sweden)

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

    Science.gov (United States)

    Sasagawa, Shota; Nishimura, Yuhei; Sawada, Hirofumi; Zhang, Erquan; Okabe, Shiko; Murakami, Soichiro; Ashikawa, Yoshifumi; Yuge, Mizuki; Kawaguchi, Koki; Kawase, Reiko; Mitani, Yoshihide; Maruyama, Kazuo; Tanaka, Toshio

    2016-01-01

    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 two genes was significantly increased in the five datasets, whereas expression of SMAD family member six 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 examined Ccdc

  14. Decreased pre-surgical CD34+/CD144+ cell number in patients undergoing coronary artery bypass grafting compared to coronary artery disease-free valvular patients

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    Redondo Santiago

    2012-01-01

    Full Text Available Abstract Background Cardiovascular disease has been linked to endothelial progenitor cell (EPC depletion and functional impairment in atherosclerosis and aortic stenosis. EPCs may play a pivotal role in vascular grafting. However, the EPC depletion in coronary artery bypass grafting (CABG patients has not been compared to coronary artery disease-free valvular replacement patients with aortic stenosis. Methods We aimed to assess the basal number of CD34+/KDR+ and CD34+/CD144+ cells in CABG patients, compared to aortic stenosis valvular replacement patients. 100 patients (51 CABG and 49 valvular surgery ones were included in the present study. All CABG or valvular patients had angiographic demonstration of the presence or the absence of coronary artery disease, respectively. Numbers of CD34+/KDR+ and CD34+/CD144+ were assessed by flow cytometry of pre-surgical blood samples. Results We found a lower number of CD34+/CD144+ cells in CABG patients compared to valvular patients (0.21 ± 0.03% vs. 0.47 ± 0.08%, and this difference remained statistically significant after the P was adjusted for multiple comparisons (P = 0.01428. Both groups had more EPCs than healthy controls. Conclusions Pre-surgical CD34+/CD144+ numbers are decreased in CABG patients, compared to valvular patients with absence of coronary disease.

  15. 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.

  16. Magnetic resonance imaging compared with echocardiography in the evaluation of pulmonary artery abnormalities in children with tetralogy of Fallot following palliative and corrective surgery

    International Nuclear Information System (INIS)

    Background. Abnormalities of the pulmonary arteries following palliative or corrective surgery for tetralogy of Fallot (TOF) are common. Our purpose was to compare the usefulness of magnetic resonance imaging (MRI) and echocardiography in the post- operative evaluation of the pulmonary arteries in children with TOF. Objective. Our hypothesis was that MRI is more sensitive than echocardiography in the detection of branch pulmonary artery abnormalities in children with TOF. Materials and methods. Pulmonary artery MRI and echocardiography were performed in 20 children following palliative and/or corrective surgery for TOF. MRI and echocardiography were compared in their ability to detect abnormalities of the pulmonary arteries. Angiographic or surgical correlation was available in 15 children. A perfusion scan for confirmation of pulmonary artery patency was available in one additional child. Results. Abnormalities of the branch pulmonary arteries identified by MRI included: absence or occlusion (2), focal stenosis (15), hypoplasia (2), aneurysm (1), and non-confluence (1). Echocardiography could not adequately visualize the right and left branch pulmonary arteries in eight and ten children, respectively. Echocardiography missed stenosis in 13 branch pulmonary arteries, patency of hypoplastic pulmonary arteries in two children, non-confluence of the pulmonary arteries in one child, and a left pulmonary artery aneurysm in one child. Abnormalities identified by MRI were confirmed in 16 children by angiography, surgery or perfusion scan. Conclusion. MRI is more sensitive than echocardiography for the evaluation of branch pulmonary artery abnormalities in children following surgery for TOF. (orig.)

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

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    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.

  18. Comparative evaluation of despeckle filtering in ultrasound imaging of the carotid artery.

    Science.gov (United States)

    Loizou, Christos P; Pattichis, Constantinos S; Christodoulou, Christodoulos I; Istepanian, Robert S H; Pantziaris, Marios; Nicolaides, Andrew

    2005-10-01

    It is well-known that speckle is a multiplicative noise that degrades the visual evaluation in ultrasound imaging. The recent advancements in ultrasound instrumentation and portable ultrasound devices necessitate the need of more robust despeckling techniques for enhanced ultrasound medical imaging for both routine clinical practice and teleconsultation. The objective of this work was to carry out a comparative evaluation of despeckle filtering based on texture analysis, image quality evaluation metrics, and visual evaluation by medical experts in the assessment of 440 (220 asymptomatic and 220 symptomatic) ultrasound images of the carotid artery bifurcation. In this paper a total of 10 despeckle filters were evaluated based on local statistics, median filtering, pixel homogeneity, geometric filtering, homomorphic filtering, anisotropic diffusion, nonlinear coherence diffusion, and wavelet filtering. The results of this study suggest that the first order statistics filter lsmv, gave the best performance, followed by the geometric filter gf4d, and the homogeneous mask area filter lsminsc. These filters improved the class separation between the asymptomatic and the symptomatic classes based on the statistics of the extracted texture features, gave only a marginal improvement in the classification success rate, and improved the visual assessment carried out by the two experts. More specifically, filters lsmv or gf4d can be used for despeckling asymptomatic images in which the expert is interested mainly in the plaque composition and texture analysis; and filters lsmv, gf4d, or lsminsc can be used for the despeckling of symptomatic images in which the expert is interested in identifying the degree of stenosis and the plaque borders. The proper selection of a despeckle filter is very important in the enhancement of ultrasonic imaging of the carotid artery. Further work is needed to evaluate at a larger scale and in clinical practice the performance of the proposed

  19. 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

  20. The Bahaviour of Non-finite Verbs in Translation: A Comparative Case Study of English, Malay and French

    Directory of Open Access Journals (Sweden)

    Mohamed Abdou Moindjie

    2016-07-01

    Full Text Available Non-finite verbs are verbs which are void of tenses but have definite meanings. Their behaviour in translation may bring about meaning loss or gain. This study is an investigation on their translation behaviour from English into Malay and French.  Analyses are carried out following Toury comparative translation theory for translation modeling. The text used is Shakespeare’s Hamlet; it is a literary text whose findings are expected to be reflexive to other genres.  The analysis reveals that English language use more non-finites verbs than Malay and French; this behaviour is determined by some factors relative to language peculiarity and language norms in terms of translators’ decisions and choices. Although English has historically some impacts on Malay language, it is found that Malay and French share more characteristics than do Malay and English as far as non-finite verb translation is concerned.Keywords: Non-finite verbs, finite verbs, language peculiarities, translatability, translation norms, English- French translation, English-Malay translation

  1. The comparative study of 64-slices spiral CT angiography with DSA in lower extremity arterial occlusive diseases

    International Nuclear Information System (INIS)

    Objective: To study the clinical value of 64-slices spiral CTA with DSA comparatively in diagnosis of lower extremity arterial occlusive diseases. Methods: 31 patients with lower extremity arterial occlusive diseases underwent 64-slice spiral CT angiography of lower extremity arteries and they also underwent digital subtraction angiography (DSA)two weeks later. Reconstruction by maximum intensity projection (MIP), volume render (VR)and multiplanar reformatting (MPR)in working-station was undertaken comparing with the bolus chase DSA and traditional DSA for diagnostic accuracy. Results: The 216 arterial segments of lower extremity were selected, including 157 segments with consistent results in demonstrating degree of stenosis by both examinations. On CT angiography, 5 segmental stenosis were overestimated and 9 were underestimated. When stenosis of detected segments is more than 50%, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of CTA were 98.21%, 96.15%, 97.22%, 96.49%, and 98.04%, respectively. Conclusion: 64-slices spiral CT angiography is an effective and reliable method for evaluating the lower extremity arterial occlusive diseases and may provide precious information for planning interventional therapy. (authors)

  2. 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-DC...

  3. 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

  4. [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.

  5. Finite Element Modeling of the Deformation of a Thin Magnetoelastic Film Compared to a Membrane Model

    Energy Technology Data Exchange (ETDEWEB)

    Barham, M; White, D; Steigmann, D; Rudd, R

    2009-04-08

    Recently a new class of biocompatible elastic polymers loaded with small ferrous particles (magnetoelastomer) was developed at Lawrence Livermore National Laboratory. This new material was formed as a thin film using spin casting. The deformation of this material using a magnetic field has many possible applications to microfluidics. Two methods will be used to calculate the deformation of a circular magneto-elastomeric film subjected to a magnetic field. The first method is an arbitrary Lagrangian-Eulerian (ALE) finite element method (FEM) and the second is based on nonlinear continuum electromagnetism and continuum elasticity in the membrane limit. The comparison of these two methods is used to test/validate the finite element method.

  6. 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.

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

    International Nuclear Information System (INIS)

    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

  8. 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

  9. Finite element analysis of vibration energy harvesting using lead-free piezoelectric materials: A comparative study

    Directory of Open Access Journals (Sweden)

    Anuruddh Kumar

    2014-06-01

    Full Text Available In this article, the performance of various piezoelectric materials is simulated for the unimorph cantilever-type piezoelectric energy harvester. The finite element method (FEM is used to model the piezolaminated unimorph cantilever structure. The first-order shear deformation theory (FSDT and linear piezoelectric theory are implemented in finite element simulations. The genetic algorithm (GA optimization approach is carried out to optimize the structural parameters of mechanical energy-based energy harvester for maximum power density and power output. The numerical simulation demonstrates the performance of lead-free piezoelectric materials in unimorph cantilever-based energy harvester. The lead-free piezoelectric material K0.5Na0.5NbO3-LiSbO3-CaTiO3 (2 wt.% has demonstrated maximum mean power and maximum mean power density for piezoelectric energy harvester in the ambient frequency range of 90–110 Hz. Overall, the lead-free piezoelectric materials of K0.5Na0.5NbO3-LiSbO3 (KNN-LS family have shown better performance than the conventional lead-based piezoelectric material lead zirconate titanate (PZT in the context of piezoelectric energy harvesting devices.

  10. 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

    BACKGROUND: Uterine fibroids are benign tumors seen in 20-40% of women of childbearing age, and these fibroids are usually treated by hysterectomy. During the last decade, embolization of the uterine arteries with polyvinyl alcohol microparticles has become an alternative treatment. PURPOSE: To...

  11. 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

  12. 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.

  13. 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....

  14. COMPARATIVE STUDY OF EXTRACRANIAL CAROTID AND VERTEBRAL ARTERY DOPPLER WITH CONTRAST ENHANCED MR ANGIOGRAPHY IN PATIENTS WITH STROKE

    Directory of Open Access Journals (Sweden)

    Archana

    2016-01-01

    Full Text Available CONTEXT Cerebrovascular accident or stroke is one of the most common causes of death. Ultrasonography of the carotid arteries is an easily available, cost effective, non-invasive method of evaluation. Treatment of stroke depends on reaching the most accurate diagnosis. Accurate and prompt diagnosis is crucial because timely and appropriate therapy can significantly reduce the risk of stroke and long-term sequelae. Several modalities of investigation are available to determine carotid artery status. The value of safe, non-invasive screening test is therefore great. AIMS The purpose of this study is to compare the diagnostic value of extracranial carotid and vertebral artery Doppler and Magnetic Resonance Angiography for the diagnosis of carotid artery pathology in patients with stroke. SETTINGS AND DESIGN The principal appealing points in favour of sonography are patient comfort, accuracy and lack of risk. MR Angiography produces reproducible three dimensional image of carotid bifurcation with good sensitivity for high-grade stenosis. METHODS AND MATERIAL After taking consent, 50 patients presenting with focal neurological deficit underwent Colour Doppler and Gadolinium enhanced MRA examination of the carotid and vertebral arteries at KIMS Hospital, Bangalore, with the help of VOLUSON 730 [WIPRO GE ULTRASOUND MACHINE] and GE SIGNA HDXT 1.5 TESLA 16 CHANNEL MRI. RESULTS The highest incidence of stroke was found in the age group of 50-70 years with male population commonly affected. The various risk factors include family history of stroke, hypertension and diabetes mellitus. Total pathologies were most commonly found on the right side. Most common site for atheromatous plaque was carotid bifurcation. Grading of stenosis was done based on the NASCET criteria and the findings of Doppler and MRA were compared. MRA had a better role than Doppler for detecting 80-99% stenosis. CONCLUSIONS MRA has progressively gained clinical relevance in the

  15. 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.

  16. 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.

  17. 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......-attendance ≥ 60% and weight loss ≥ 5%, respectively. CFR was assessed by Doppler echocardiography of the LAD. Peripheral vascular function was assessed by arterial tonometry as reactive hyperaemia index (RHI) and augmentation index. Most participants had impaired CFR with a mean CFR of 2.38 (SD 0.59). Twenty...... might impact prognosis of CAD through improvement of coronary microvascular function. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01724567....

  18. Finite Difference Radiative Transfer Model Calculations Compared to Measurements at the Top and Bottom of the Atmosphere

    Science.gov (United States)

    LeCroy, Stuart R.; Whitlock, Charles H.; Suttles, John T.

    1997-01-01

    A finite difference radiative transfer program was developed to handle most anisotropic scattering and reflectance problems encountered in the Earth's atmospheric system. The model has been used to reproduce the radiance received by both satellite and ground based radiation measuring instruments. It accurately replicates the radiance measured by both narrow and wide field-of-view instruments with either narrow or broadband wavelength ranges located on the surface and at satellite altitudes. The output of the finite difference code is compared to the measurements by surface pyranometers and a spectroradiometer aboard a high flying aircraft. The program output is also compared to ERBE measurements aboard the ERBS and NOAA-9 satellites as well as the visible bands aboard the GOES-6 and GOES-7 satellites and AVHRR bands 1 and 2 of the NOAA-9 and NOAA-1 1 satellites. The model is within 0.2 % of the radiance received by pyranometers, within 0.6 % of the ERBE radiances, and within 3 % of the radiances measured by the visible bands of the GOES and NOAA AVHRR radiometers.

  19. 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

  20. Cross-Sectional Elasticity Imaging of Arterial Wall by Comparing Measured Change in Thickness with Model Waveform

    Science.gov (United States)

    Tang, Jiang; Hasegawa, Hideyuki; Kanai, Hiroshi

    2005-06-01

    For the assessment of the elasticity of the arterial wall, we have developed the phased tracking method [H. Kanai et al.: IEEE Trans. Ultrason. Ferroelectr. Freq. Control 43 (1996) 791] for measuring the minute change in thickness due to heartbeats and the elasticity of the arterial wall with transcutaneous ultrasound. For various reasons, for example, an extremely small deformation of the wall, the minute change in wall thickness during one heartbeat is largely influenced by noise in these cases and the reliability of the elasticity distribution obtained from the maximum change in thickness deteriorates because the maximum value estimation is largely influenced by noise. To obtain a more reliable cross-sectional image of the elasticity of the arterial wall, in this paper, a matching method is proposed to evaluate the waveform of the measured change in wall thickness by comparing the measured waveform with a template waveform. The maximum deformation, which is used in the calculation of elasticity, was determined from the amplitude of the matched model waveform to reduce the influence of noise. The matched model waveform was obtained by minimizing the difference between the measured and template waveforms. Furthermore, a random error, which was obtained from the reproducibility among the heartbeats of the measured waveform, was considered useful for the evaluation of the reliability of the measured waveform.

  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. 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.

    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

  3. 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.

  4. Non-invasive continuous arterial pressure and pulse pressure variation measured with Nexfin(®) in patients following major upper abdominal surgery: a comparative study.

    Science.gov (United States)

    de Wilde, R B P; de Wit, F; Geerts, B F; van Vliet, A L; Aarts, L P H J; Vuyk, J; Jansen, J R C

    2016-07-01

    We compared the accuracy and precision of the non-invasive Nexfin(®) device for determining systolic, diastolic, mean arterial pressure and pulse pressure variation, with arterial blood pressure values measured from a radial artery catheter in 19 patients following upper abdominal surgery. Measurements were taken at baseline and following fluid loading. Pooled data results of the arterial blood pressures showed no difference between the two measurement modalities. Bland-Altman analysis of pulse pressure variation showed significant differences between values obtained from the radial artery catheter and Nexfin finger cuff technology (mean (SD) 1.49 (2.09)%, p agreement -2.71% to 5.69%). The effect of volume expansion on pulse pressure variation was identical between methods (concordance correlation coefficient 0.848). We consider the Nexfin monitor system to be acceptable for use in patients after major upper abdominal surgery without major cardiovascular compromise or haemodynamic support. PMID:27291598

  5. Anastomose arterial com fio de polidioxanona e fio de polipropileno. Estudo comparativo em cães Arterial anastomose with polydioxanone and polypropilene suture. Comparative study in dogs

    Directory of Open Access Journals (Sweden)

    Eloísa de Brida Tormena

    2002-03-01

    Full Text Available Este estudo teve por objetivo comparar os efeitos do fio absorvível de polidioxanona com o fio inabsorvível de polipropileno, em anastomoses término-terminais, em artérias femorais de cães. Foram utilizados 20 cães, separados em dois grupos, para observação no 7º e no 30º dia de pós-operatório. Cada cão teve suas artérias femorais seccionadas e aproximadas em um lado com pontos separados de fio de polidioxanona 6-0, e no lado contralateral com o fio de polipropileno 6-0. A escolha do fio foi feita por sorteio, totalizando 40 anastomoses. Para análise estatística dos resultados aplicaram-se os testes de Fisher, Mac Nemar, Wilcoxon, Mann-Witney e o teste T de Student (a ≤ 0,05. Nas avaliações clínicas não foram observadas diferenças significantes entre os fios utilizados. Os resultados obtidos nas avaliações arteriográfica e macroscópica dos segmentos arteriais foram semelhantes, assim como na análise histológica morfológica. Na análise histológica morfométrica o fio de polipropileno apresentou número de células gigantes de corpo estranho significativamente maior que o fio de polidioxanona aos 7 e 30 dias de pós-operatório. Os resultados nos permitem concluir que, apesar da maior reação de corpo estranho observada com o fio de polipropileno, o fio de polidioxanona apresentou resultados semelhantes ao fio de polipropileno, em anastomoses arteriais em cães.The objetive of this study was to compare the effects of the absorbable polidioxanone suture to the nonabsorbable polypropylene suture, in end-to-end anastomoses, using dog’s femoral arteries. Twenty dogs were separated in two groups for observation on the 7th and 30th post-operatory day. Each dog had its femoral arteries seccioned and then aproximated one side with separate stitches of polidioxanone 6-0 suture, and the other side with polypropylene 6-0 suture. For the statistical studies Fisher, Mac nemar, Wilsoxon, Mann-Witney and T of Student tests (a

  6. 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.

  7. Comparing Ovarian Radiation Doses in Flat-Panel and Conventional Angiography During Uterine Artery Embolization: A Randomized Clinical Trial

    International Nuclear Information System (INIS)

    Uterine artery embolization (UAE) is a minimally invasive procedure performed under fluoroscopy for the treatment of uterine fibroids and accompanied by radiation exposure. To compare ovarian radiation doses during uterine artery embolization (UAE) in patients using conventional digital subtraction angiography (DSA) with those using digital flat-panel technology. Thirty women who were candidates for UAE were randomly enrolled for one of the two angiographic systems. Ovarian doses were calculated according to in-vitro phantom study results using entrance and exit doses and were compared between the two groups. The mean right entrance dose was 1586±1221 mGy in the conventional and 522.3±400.1 mGy in the flat panel group (P=0.005). These figures were 1470±1170 mGy and 456±396 mGy, respectively for the left side (P=0.006). The mean right exit dose was 18.8±12.3 for the conventional and 9.4±6.4 mGy for the flat panel group (P=0.013). These figures were 16.7±11.3 and 10.2±7.2 mGy, respectively for the left side (P=0.06). The mean right ovarian dose was 139.9±92 in the conventional and 23.6±16.2 mGy in the flat panel group (P<0.0001). These figures were 101.7±77.6 and 24.6±16.9 mGy, respectively for the left side (P=0.002). Flat panel system can significantly reduce the ovarian radiation dose during UAE compared with conventional DSA

  8. 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

  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

    International Nuclear Information System (INIS)

    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. 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.

  11. 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.

  12. 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

  13. 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.

  14. Bronchopulmonary arterial anastomosis at the precapillary level in human lung. Visualization using CT angiography compared with microangiography of autopsied lung

    International Nuclear Information System (INIS)

    To investigate the interrelationships between the bronchial and pulmonary circulations including the existence of precapillary bronchopulmonary arterial anastomoses, CT of bronchial arteriography (BAG-CT) was performed in 10 patients and BAG-CT during a pulmonary artery block test (PA-block) in 5 patients with lung cancer. Bronchial and pulmonary circulations were evaluated in 5 autopsied normal lungs by injecting silicone rubber with different colors into the bronchial and pulmonary arteries. BAG-CT correlated well with the findings at silicone rubber injection into lung autopsy samples. BAG-CT demonstrated inflow of contrast medium into the pulmonary artery during PA-block in all cases, while no inflow was observed before and following reversal of PA-block. Mixed silicone rubber was observed in the lobar to subsubsegmental bronchial arteries in all cases and in the subsubsegmental pulmonary artery in one case. Precapillary bronchopulmonary arterial anastomoses may exist at the level of the lobar bronchi to the periphery. If either the pulmonary or bronchial circulation is disturbed, flow occurs inside the anastomoses to supplement the other flow, especially flow from the bronchial to the pulmonary arteries via the anastomoses, which occurs within 30 min

  15. Bronchopulmonary arterial anastomosis at the precapillary level in human lung. Visualization using CT angiography compared with microangiography of autopsied lung

    International Nuclear Information System (INIS)

    Purpose: To investigate the interrelationships between the bronchial and pulmonary circulations including the existence of precapillary bronchopulmonary arterial anastomoses. Material and Methods: CT of bronchial arteriography (BAG-CT) was performed in 10 patients and BAG-CT during a pulmonary artery block test (PA-block) in 5 patients with lung cancer. Bronchial and pulmonary circulations were evaluated in 5 autopsied normal lungs by injecting silicone rubber with different colors into the bronchial and pulmonary arteries. Results: BAG-CT correlated well with the findings at silicone rubber injection into lung autopsy samples. BAG-CT demonstrated inflow of contrast medium into the pulmonary artery during PA-block in all cases, while no inflow was observed before and following reversal of PA-block. Mixed silicone rubber was observed in the lobar to subsubsegmental bronchial arteries in all cases and in the subsubsegmental pulmonary artery in one case. Conclusion: Precapillary bronchopulmonary arterial anastomoses may exist at the level of the lobar bronchi to the periphery. If either the pulmonary or bronchial circulation is disturbed, flow occurs inside the anastomoses to supplement the other flow, especially flow from the bronchial to the pulmonary arteries via the anastomoses, which occurs within 30 min. (orig.)

  16. 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

  17. 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...

  18. 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.

  19. 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.

  20. 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.

  1. Comparative study of myocardial perfusion imaging and 64 multi-slice spiral CT for the diagnosis of coronary artery disease

    International Nuclear Information System (INIS)

    Objective: To compare the diagnostic value of myocardial perfusion imaging (MPI) and 64 multi-slice spiral CT (64-MSCT) for coronary artery disease (CAD). Methods: Fifty-two patients with suspected or known CAD were included in the study. Each patient underwent both stress and rest MPI, MSCT as well as conventional coronary angiography (CAG) within 1 month. The stress and rest MPI were scored by a 5-grade criteria (0-4) based on 17 coronary artery segments. The difference between summed stress and rest scores > 1 was defined as myocardial ischemia. Stenosis in one main vessel or one main branch of the main vessel ≥50% was defined as myocardial ischemia by MSCT. CAG was used as the reference for comparison. Statistical analysis was performed using SPSS 13.0 software. Kappa value was used to test the accordance of MPI and MSCT results. χ2 test was used to evaluate the difference between MPI and MSCT results. Results: The patient-based sensitivity, specificity, positive and negative predictive values and accuracy of MPI and MSCT for the diagnosis of CAD were 86.7% (26/30), 77.3% (17/22),83.9% (26/31), 81.0% (17/21), 82.7% (43/52) and 83.3% (25/30), 86.4% (19/22), 89.3%( 25/28), 79.2% (19/24), 84.6% (44/52), respectively. The vessel-based sensitivity, specificity, positive and negative predictive values and accuracy of MPI and MSCT were 74.5% (38/51), 81.0% (85/105), 65.5% (38/58), 86.7% (85/98), 78.8% (123/156) and 90.2% (46/51), 88.6% (93/105),79.3 % (46/58), 94.9% (93/98), 89.1% (139/156), respectively. There was no statistically significant difference between MPI and MSCT for either patient or lesion-based diagnosis (χ2 =0.44, 0.21, both P>0.05). 96.0% (24/25) patients with both abnormal MPI and MSCT positive were validated by CAG while 83.3% (15/18) patients with both MPI and MSCT negative were excluded by CAG. Conclusions: Both MPI and MSCT are reliable diagnostic modalities for CAD. They also provide complementary diagnostic value to each other. (authors)

  2. Acute cerebrovascular incident in a young woman: Venous or arterial stroke? – Comparative analysis based on two case reports

    International Nuclear Information System (INIS)

    Cerebrovascular diseases are the most common neurological disorders. Most of them are arterial strokes, mainly ischemic, less often of hemorrhagic origin. Changes in the course of cerebral venous thrombosis are less common causes of acute cerebrovascular events. Clinical and radiological presentation of arterial and venous strokes (especially in emergency head CT) may pose a diagnostic problem because of great resemblance. However, the distinction between arterial and venous stroke is important from a clinical point of view, as it carries implications for the treatment and determinates patient’s prognosis. In this article, we present cases of two young women (one with an acute venous infarction, the second with an arterial stroke) who presented with similar both clinical and radiological signs of acute vascular incident in the cerebral cortex. We present main similarities and differences between arterial and venous strokes regarding the etiology, clinical symptoms and radiological appearance in various imaging techniques. We emphasize that thorough analysis of CT (including cerebral vessels), knowledge of symptoms and additional clinical information (e.g. risk factors) may facilitate correct diagnosis and allow planning further diagnostic imaging studies. We also emphasize the importance of MRI, especially among young people, in the differential diagnosis of venous and arterial infarcts

  3. Acute cerebrovascular incident in a young woman: Venous or arterial stroke? – Comparative analysis based on two case reports

    Science.gov (United States)

    Sleiman, Katarzyna; Zimny, Anna; Kowalczyk, Edyta; Sąsiadek, Marek

    2013-01-01

    Summary Background Cerebrovascular diseases are the most common neurological disorders. Most of them are arterial strokes, mainly ischemic, less often of hemorrhagic origin. Changes in the course of cerebral venous thrombosis are less common causes of acute cerebrovascular events. Clinical and radiological presentation of arterial and venous strokes (especially in emergency head CT) may pose a diagnostic problem because of great resemblance. However, the distinction between arterial and venous stroke is important from a clinical point of view, as it carries implications for the treatment and determinates patient’s prognosis. Case Report In this article, we present cases of two young women (one with an acute venous infarction, the second with an arterial stroke) who presented with similar both clinical and radiological signs of acute vascular incident in the cerebral cortex. We present main similarities and differences between arterial and venous strokes regarding the etiology, clinical symptoms and radiological appearance in various imaging techniques. Conclusions We emphasize that thorough analysis of CT (including cerebral vessels), knowledge of symptoms and additional clinical information (e.g. risk factors) may facilitate correct diagnosis and allow planning further diagnostic imaging studies. We also emphasize the importance of MRI, especially among young people, in the differential diagnosis of venous and arterial infarcts. PMID:24505227

  4. 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.

  5. Comparing the Effects of Morphine Sulfate and Diclofenac Suppositories on Postoperative Pain in Coronary Artery Bypass Graft Patients

    Science.gov (United States)

    Imantalab, Vali; Mirmansouri, Ali; Sedighinejad, Abbas; Naderi Nabi, Bahram; Farzi, Farnoush; Atamanesh, Hadi; Nassiri, Nassir

    2014-01-01

    Background: Simple and efficient way of pain management after Coronary Artery Bypass Graft (CABG) surgery is an important aspect of patients' care. Objectives: This study aimed to compare the effects of morphine and diclofenac suppositories on postoperative pain management. Patients and Methods: In this double-blinded clinical trial study, 120 patients aged 30-65 years old, undergone CABG, were equally divided into two groups of A (morphine) and B (diclofenac). All patients were anesthetized with intravenous fentanyl 10 μg/kg, etomidate 0.2 mg/kg and cisatracurium 0.2 mg/kg. Anesthesia was maintained with oxygen 50% and air 50%, propofol 50 μg/kg/min, fentanyl 1-2 μg/kg/h and atracurium 0.6 mg/kg/h. Analgesics were administered after the operation at intensive care unit (ICU) and Visual Analogue Score (VAS) was evaluated in both groups in 4-hour intervals after extubation for 24 hours. After extubation in case of VAS > 3, morphine suppository 10 mg (group A) or diclofenac suppository 50 mg (group B) was administered for patients. Results: No significant statistical relationship was found between the two groups regarding gender, age, BMI, paracetamol consumption, length of operation time, cardiopulmonary bypass pump (CPB) time, and stay time at ICU (P Value ≥ 0.05). Total dosage of used morphine was 22 ± 8.3 mg in each patient and total dosage of used diclofenac was 94 ± 32.01 mg. Average variation of VAS at measured intervals was significant (P Value ≤ 0.0001), but these variations were not significantly different when comparing the two groups (P Value = 0.023). Conclusions: Both morphine and diclofenac suppositories reduced pain significantly and similarly after CABG surgery. PMID:25346897

  6. 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.

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

    OpenAIRE

    Claudio Ferone; Francesco Colangelo; Domenico Frattini; Giuseppina Roviello; Raffaele Cioffi; Rosa di Maggio

    2014-01-01

    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 vario...

  8. 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.

  9. Comparative study on percutaneous coronary intervention of unprotected left main coronary artery disease: transradial versus transfemoral approach

    Directory of Open Access Journals (Sweden)

    Quan-min JING

    2011-11-01

    Full Text Available Objective To compare the safety,feasibility,and clinical efficacy of transradial approach(TRA percutaneous coronary intervention(PCI with transfemoral approach(TFA PCI for unprotected left main coronary artery(ULMCA disease.Methods The current study selected 286 patients who underwent PCI for ULMCA lesions in the General Hospital of Shenyang Military Region between Jan.2007 and Dec.2008,which included 144(TRA group patients with TRA PCI and 142(TFA group with TFA PCI for review analysis.Difference in coronary angiography(CAG,operation success rate,implantation of complex bifurcate lesion stent,X-ray exposure period,contrast agent dosage,local vascular complications,major adverse cardiac events(MACE rate during hospitalization and visiting period,post-PCI ambulation,post-PCI hospitalization period,and the total hospitalization period between the two groups were compared.Results The two groups have similar baseline features.The difference between the TRA and TFA groups in CAG and operation success rate(96.5% and 98.6% for TRA and 92.3% and 97.9% for TFA,respectively has no statistical significance(P=0.116,P=0.641.The difference between the TRA and TFA groups in terms of implantation rate(29.9% vs 26.8% of complex bifurcate lesion stent(crushed,culotte,T stent,exposure period(53.1min±10.42min vs 51.23min±9.80min,and contrast agent dosage(247.66ml±106.98ml vs 267.26ml±136.09ml has no statistical significance(P=0.561,P=0.105,P=0.175.The TRA group has lower local vascular complications(10.4% vs 19.7% than the TFA group(P=0.028.MACE during hospitalization in the TRA group(6.3% is lower than that in the TFA group(12.7%,but the difference has no statistical significance(P=0.066.Neither group has post-PCI myocardial infarction,stroke,or emergency coronary artery bypass grafting.The TRA group has shorter(P < 0.001 post-PCI ambulation period(1.37days±0.62days vs 2.40days±1.45days,post-PCI hospitalization period(4.16days±3.19days vs 7.75days±5.29days

  10. Intra-arterial infusion of MTX for the treatment of cesarean scar pregnancy: a comparative study between different doses

    International Nuclear Information System (INIS)

    Objective: To investigate the effective dose of methotrexate (MTX) via intra-arterial infusion for the treatment of cesarean scar pregnancy. Methods: Thirty-six cases of incisional scar pregnancy at the gestational age of 5-9 weeks received bilateral uterine arterial infusion of MTX. According to the dose of MTX used, the patients were randomly and equally divided into four groups with MTX dose of 60, 100, 150 and 200 mg respectively. After the perfusion was completed the embolization of both uterine arteries with Gelfoam was carried out until the uterine arteries were no longer visualized on DSA. Uterine curettage was conducted within 1-7 days after the treatment. Results: In one week after the procedure, the difference in the decreasing rate of serum β-HCG and progesterone between group 60 mg and group 200 mg was of statistical significance (P 0.05). The hospitalization days of group 60 mg was the longest, while that of group 200 mg was the shortest. Conclusion: The recommended dose of MTX used via intra-arterial infusion in treating cesarean scar pregnancy is 200 mg. The interventional procedure can kill the embryo tissue and quickly lower the serum β-HCG and progesterone levels,it can also shorten the patient's hospitalization time. (authors)

  11. Comparative study of coronary flow reserve, coronary anatomy and results of radionuclide exercise tests in patients with coronary artery disease

    International Nuclear Information System (INIS)

    A comparative assessment of regional coronary flow reserve, quantitative percent diameter coronary stenosis and exercise-induced perfusion and wall motion abnormalities was performed in 39 patients with coronary artery disease. Coronary flow reserve was determined by a digital angiographic technique utilizing contrast medium as the hyperemic agent. Percent diameter stenosis was calculated by an automated quantification program applied to orthogonal cineangiograms. Thallium-201 scintigraphy and radionuclide ventriculography were used to assess regional perfusion and wall motion abnormalities, respectively, at rest and during exercise. In Group A, 19 patients without transmural infarction or collateral vessels, coronary flow reserve was inversely related to percent diameter stenosis (r = -0.61, p less than 0.0001), and scintigraphic abnormalities occurred only in vascular distributions with a coronary flow reserve of less than 2.00. There was a strong relation among abnormal regional exercise results, stenoses greater than 50% and reactive hyperemia of less than 2.00. Patients with multivessel disease, however, often had normal exercise scintigrams in regions associated with greater than 50% stenosis and low coronary flow reserve when other regions had a lower coronary flow reserve or higher grade stenosis, or both. In Group B, 20 patients with angiographically visible collateral vessels, 12 of whom had prior myocardial infarction, coronary flow reserve correlated less well with percent diameter stenosis than in Group A (r = -0.47, p less than 0.004). As in Group A patients, there was a significant relation between abnormal exercise test results and stenoses greater than 50%. However, reactive hyperemia values were generally lower than in Group A, and positive exercise stress results were strongly correlated only with highly impaired flow reserves of 1.3 or less

  12. Evaluation of batroxobin in preventing vascular restenosis in diabetic patients after infrapopliteal arterial angioplasty: a randomized comparative study

    International Nuclear Information System (INIS)

    Objective: To evaluate batroxobin in preventing vascular restenosis in diabetic patients after infrapopliteal arterial angioplasty through comparing the clinical results of the combination use of batroxobin and aspirin with that of simple use of aspirin. Methods: After a successful angioplasty, fifty-two diabetic patients with symptomatic infrapopliteal obstructions were randomly divided into the study group (n=26) and the control group (n=26). Patients in both groups received 100 aspirin everyday, but the patients in study group additionally received 5 IU batroxobin intravenous drip every day for six times. At the end of the follow-up period lasting for 12 months, magnetic resonance angiography (MRA) or Doppler ultrasonic angiography was performed to check the vessels to see if there was any restenosis or reocclusion. The relief degree of clinical symptoms were observed, and both preoperative and postoperative ankle-brachial index (ABI) were regularly determined and compared. Kaplan-Meier curves were constructed to evaluate restenosis/reocclusion-free rate, limb salvage rate and amputation-free rate. Results: During the follow-up period the occurrence of restenosis/reocclusion in study group and control group was 22.0% and 34.5% respectively (P=0.0307). Statistically significant difference in ABI existed between two groups both after the procedure (P<0.05) and at 12 months after the treatment (P=0.0094). Clinical improvement and tissue healing in study group and control group were observed in 23 and 19 patients respectively (P=0.0544). Twelve months after angioplasty, Kaplan-Meier analysis showed that the restenosis/reocclusion-free rate, the limb salvage rate and the amputation-free rate for study group were 74.0%, 96.2% and 84.6% respectively, while they was 54.8%, 92.3% and 84.6% respectively for control group. Conclusion: The results of this study indicate that the use of the clinical therapeutic efficacy and markedly relieve the symptoms, although this

  13. COMPARATIVE EVALUATION OF THE ANTIHYPERTENSIVE EFFECT OF PERINDOPRIL AND LOSARTAN POTASSIUM IN PATIENTS WITH ARTERIAL HYPERTENSION AND STENOTIC CORONARY ATHEROSCLEROSIS BEFORE REVASCULARIZATION: AN OPEN RANDOMIZED COMPARATIVE STUDY

    Directory of Open Access Journals (Sweden)

    O. A. Osipova

    2011-01-01

    Full Text Available Aim. To compare effects of perindopril and losartan potassium on the parameters of the ambulatory blood pressure (BP monitoring (ABPM and circadian BP profile in patients with arterial hypertension (HT and stenotic coronary atherosclerosis before myocardium revascularization. Material and methods. 59 patients with HT degree 2-3 at the age of 35-69 were examined. ABPM was performed in all patients. Daily profile was assessed by the degree of nocturnal BP reduction. Patients were randomized to receive perindopril or losartan potassium. Perindopril was administered at dose of 4 mg/day with subsequent rising up to 8 mg/day in next 7 days. The initial dose of losartan potassium was 25 mg with subsequent rising up to 50 mg 2 times a day. Duration of observation was 8 weeks. Results. Perindopril reduced 24-hour and daytime systolic BP (SBP by 17.2% (p<0.0001, nighttime SBP - by 22.5% (p<0.0001, 24-hour and daytime diastolic BP (DBP - by 18.3% and 17.6% (p<0.0001, respectively , nighttime DBP - by 27.2% (p<0.0001. Losartan potassium reduced 24-hour SBP by 25.7% (p<0.0001, daytime SBP - by 23.6% (p<0.0001, night-time SBP – by 25.5% (p<0.0001, 24-hour DBP - by 27.4%, daytime DBP - by 26.3%, nighttime DBP - by 18.5% (p=0.003. Perindopril decreased in number of non-dippers by 24,3% and night-peakers by 5.4% as well as increased in number of dippers by 27% and over-dippers by 2.7%. A number of patients with SAD profile corresponding to non-dipper type was 45.5% more in losartan taking than this when perindopril receiving (p=0.027. Conclusion. In patients with HT and stenotic coronary atherosclerosis perindopril therapy increases a number of patients with normal BP profile before myocardium revascularization.

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

    OpenAIRE

    Jensen, Thomas; Duun, Sune Bro; Larsen, Jan; Haahr, Rasmus Grønbek; Toft, M. H.; Belhage, B.; Thomsen, Erik Vilain

    2009-01-01

    We examine various independent component analysis (ICA) digital signal processing algorithms for estimating the arterial oxygen saturation (SpO2) as measured by a reflective pulse oximeter. The ICA algorithms examined are FastICA, Maximum Likelihood ICA (ICAML), Molgedey and Schuster ICA (ICAMS), 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 commer...

  15. Less invasive coronary artery revascularization with a minimized extracorporeal circulation system: preliminary results of a comparative study with off-pump-procedures

    OpenAIRE

    Wittwer, Thorsten; Sabashnikov, Anton; Rahmanian, Parwis B; Choi, Yeong-Hoon; Zeriouh, Mohamed; Mehler, Thorsten O; Wahlers, Thorsten

    2013-01-01

    Background Coronary-artery-bypass-grafting (CABG) with conventional extracorporeal circulation (CECC) is associated with adverse effects such as systemic inflammatory response leading to a decrease in systemic vascular resistance and hemodynamic instability. Modern "less invasive" procedures have been established recently which potentially avoid negative side effects of CECC. The aim of this study was to compare perioperative outcome following coronary revascularization using either a minimiz...

  16. 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

    OpenAIRE

    Jinqiu Yang; Lukui Chen; Naveen Chitkara; Qiang Xu

    2014-01-01

    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 sten...

  17. 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

    OpenAIRE

    Amit Agarwal; Kanupriya Vijay; Krishnamoorthy Thamburaj; Sangam Kanekar; Paul Kalapos

    2014-01-01

    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...

  18. 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.

  19. Transmission in nonuniform ducts - A comparative evaluation of finite element and weighted residuals computational schemes. [acoustic propagation

    Science.gov (United States)

    Eversman, W.; Astley, R. J.; Thanh, V. P.

    1977-01-01

    The Method of Weighted Residuals (MWR) and the Finite Element Method (FEM) are considered as computational schemes in the problem of acoustic transmission in nonuniform ducts. MWR is presented in an improved form which includes the interaction of acoustic modes (irrotational) and hydrodynamic modes (rotational). FEM is based on a weighted residuals formulation using eight noded isoparametric elements. Both are applicable to two-dimensional and axially symmetric problems. Calculations are made for several sample problems to demonstrate accuracy and relative efficiency. One test case has implications in the phenomenon of subsonic acoustic choking and it is found that a large transmission loss is not an automatic consequence of propagation against a high subsonic mean flow.

  20. [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.

  1. 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.

  2. ALL-CERAMIC AND PORCELAIN-FUSED-TO-METAL FIXED PARTIAL DENTURES: A COMPARATIVE STUDY BY 2D FINITE ELEMENT ANALYSES

    OpenAIRE

    Andréa Barreira Motta; Luiz Carlos Pereira; da Cunha, Andréia R.C.C

    2007-01-01

    All-ceramic fixed partial dentures (FPDs) have an esthetic approach for oral rehabilitation. However, metal-ceramic FPDs are best indicated in the posterior area where the follow-up studies found a lower failure rate. This 2D finite element study compared the stress distribution on 3-unit all-ceramic and metal-ceramic FPDs and identified the areas of major risk of failure. Three FPD models were designed: (1) metal-ceramic FPD; (2) All-ceramic FPD with the veneering porcelain on the occlusal a...

  3. 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

  4. Comparative Finite Element Analysis of Short Implants and Lateralization of the Inferior Alveolar Nerve With Different Prosthesis Heights.

    Science.gov (United States)

    Jayme, Sérgio J; Ramalho, Paulo R; De Franco, Leonardo; Jugdar, Ricardo Elias; Shibli, Jamil Awad; Vasco, Marco A A

    2015-11-01

    The lateralization of the inferior alveolar nerve (LIAN) and short implants are efficient options for rehabilitation of the posterior atrophic mandible. However, the loss of bone leads to prosthesis with greater height and lever effect that in turn can have different impact on treatments. Through the finite element method, the present study tests the hypothesis that conventional implants placed under LIAN and short implants have similar risk of bone loss regarding variable height of the crown and that crown-to-implant ratio is not a reliable resource to evaluate risk in these treatments. Computed tomography scans of mandibles were processed and implants and prosthetic components were reverse engineered for reconstruction of three-dimensional models to simulate 3 elements fixed partial dentures supported by 2 osseointegrated implants. The models of implants were based on MK III implants (Nobel Biocare, Zurich, Switzerland) with 4 mm in diameter by 7 mm in length representing short implants, and 15 mm in length representing implants used in LIAN. The implant/crown ratio for short implants was 1:1.5, 1:2, and 1:2.5 and LIAN models were modeled with exactly the same prosthesis, resulting in implant/crown ratios of 1:0.67, 1:0.89, and 1:1.12. The results partially rejected the hypothesis that LIAN and short implants have similar risk of bone loss, showing that although LIAN results were better in the models evaluated, the variations in height had proportionally similar impact on both treatments and accepted the hypothesis that crown-to-implant ratio was not a reliable resource to evaluate risk. PMID:26491923

  5. 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.

  6. Peripheral Arterial Disease. Contrast-Enhanced 3D MR Angiography of the Lower Leg and Foot Compared with Conventional Angiography

    International Nuclear Information System (INIS)

    Purpose: To determine whether contrast-enhanced 3D MR angiography (CE MRA) could replace digital subtraction angiography (DSA) for the evaluation of atherosclerotic peripheral vascular disease of the lower leg and foot. Material and Methods: Thirty-five patients with symptoms of atherosclerotic disease of the leg were examined prospectively with CE MRA of the foot and the lower legs as well as with DSA from the aorta to the pedal arches. The MRA technique was focused on optimal imaging of the arteries of the foot. Results: The agreement between CE MRA and DSA for grading of stenosis was moderate to good (weighted -values 0.48-0.80). The sensitivity of CE MRA for detection of significant stenosis (50%) was 92% and the specificity was 64% with DSA as gold standard. Conclusion: CE MRA is a fairly accurate method for the demonstration of atherosclerotic disease below the knee including the pedal arches. It can replace DSA for the assessment of distal arteries in patients with impaired renal function. However, image quality and resolution still needs to be improved before CE MRA can become the method of choice in all patients

  7. Comparative evaluation of stresses in tooth implant connected fixed partial denture by varying the implant design and position: A 3D finite element study

    Directory of Open Access Journals (Sweden)

    K V Pratheep

    2013-01-01

    Full Text Available Aim: This study aims at evaluating stresses generated in a fixed tooth to implant connected fixed partial denture (FPD by finite element method by varying implant design and position, in unilateral distal extension cases, i.e. for replacing mandibular 1 st and 2 nd molars. Materials and Methods: Four models were created, Model 1-A finite element model (FEA model of a crestal implant-tooth connected metal ceramic FPD with pontic in 36 region. The 35 region simulated the second premolar. Model 2-A FEA model of a basal implant-tooth connected metal ceramic FPD. Model 3-A FEA model of a crestal implant in 36 region connected to tooth 35 and cantilevered posteriorly with pontic in 37 region, made of metal ceramic. Model 4-A FEA model of a basal implant in 36 region connected to tooth 35 and cantilevered posteriorly with pontic in 37 region, made of metal ceramic. A vertical force of 100N directed evenly on the nodes on the occlusal surface of each of the three crowns. The models displayed stress both numerically and by color coding. Results: On comparing models 1 and 2, the model 1 showed comparatively more stresses in crestal bone area of the implant. On comparing models 3 and 4, model 3 showed lesser von misses stress values. Conclusion: In case of tooth implant connected FPDs without any cantilevers, basal implants show better stress distribution when compared to crestal implants. In case of cantilever designs, crestal implant design showed lower stress values, but the difference in stresses were less.

  8. 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

  9. Combination of pulse volume recording (PVR) parameters and ankle-brachial index (ABI) improves diagnostic accuracy for peripheral arterial disease compared with ABI alone.

    Science.gov (United States)

    Hashimoto, Tomoko; Ichihashi, Shigeo; Iwakoshi, Shinichi; Kichikawa, Kimihiko

    2016-06-01

    The ankle-brachial index (ABI) measurement is widely used as a screening tool to detect peripheral arterial disease (PAD). With the advent of the oscillometric ABI device incorporating a system for the measurement of pulse volume recording (PVR), not only ABI but also other parameters, such as the percentage of mean arterial pressure (%MAP) and the upstroke time (UT), can be obtained automatically. The purpose of the present study was to compare the diagnostic accuracy for PAD with ABI alone with that of a combination of ABI, %MAP and UT. This study included 108 consecutive patients on whom 216 limb measurements were performed. The sensitivity, specificity and positive and negative predictive values of ABI, %MAP, UT and their combination were evaluated and compared with CT angiography that was used as a gold standard for the detection of PAD. The diagnostic accuracy as well as the optimal cutoff values of %MAP and UT were evaluated using receiver operating characteristic (ROC) curve analysis. The combination of ABI, %MAP and UT achieved higher sensitivity, negative predictive value and accuracy than ABI alone, particularly for mild stenosis. The areas under the ROC curve for the detection of 50% stenosis with UT and %MAP were 0.798 and 0.916, respectively. The optimal UT and %MAP values to detect ≧50% stenosis artery were 183 ms and 45%, respectively. The combination of ABI, %MAP and UT contributed to the improvement of the diagnostic accuracy for PAD. Consideration of the values of %MAP and UT in addition to ABI may have a significant impact on the detection of early PAD lesions.

  10. Variations in the Prevalence of Risk Factors for Coronary Artery Disease in Rio Grande do Sul-Brazil: A Comparative Analysis between 2002 and 2014

    Directory of Open Access Journals (Sweden)

    Iseu Gus

    2015-01-01

    Full Text Available AbstractBackground:Due to the importance of coronary artery disease (CAD, continuous investigation of the risk factors (RFs is needed.Objective:To evaluate the prevalence of RFs for CAD in cities in Rio Grande do Sul State, and compare it with that reported in a similar study conducted in the same cities in 2002.Methods:Cross-sectional study on 1,056 healthy adults, investigating the prevalence and absolute and relative frequencies of the following RFs for CAD: obesity, systemic arterial hypertension (SAH, dyslipidemias, smoking, sedentary lifestyle, diabetes mellitus, and family history, as well as age and sex. Data was collected in 19 cities, host of the Offices of the Regional Coordinators of Health, as in the 2002 study.Results:Twenty-six percent of the sample consisted of older adults and 57% were women. The prevalence of sedentary lifestyle was 44%, history family 50%, smoking 23%, overweight/obesity 68%, dyslipidemia (high cholesterol levels 43%, SAH 40%, and diabetes 11%. When compared to the 2002 study, the prevalence of active smoking and sedentary behavior decreased, whereas the prevalence of hypertension, dyslipidemia and obesity increased. Obesity is the most prevalent RF in women, and SAH the most prevalent in men.Conclusions:The prevalence of RFs for CAD in Rio Grande do Sul State remains high. Hypertension, obesity and dyslipidemia are still prevalent and require major prevention programs. Smoking and physical inactivity have decreased in the state, suggesting the efficacy of related campaigns.

  11. Finite Divergence

    DEFF Research Database (Denmark)

    Hansen, Michael Edberg; Pandya, P. K.; Chaochen, Zhou

    1995-01-01

    of behaviour arises in many representations of hybrid systems, and also in theories of nonlinear systems. The aim is to provide a theory where pathological behaviour such as finite divergence can be analysed-if only to prove that it does not occur in systems of interest. Finite divergence is studied using......Real-time and hybrid systems have been studied so far under the assumption of finite variability. In this paper, we consider models in which systems exhibiting finite divergence can also be analysed. In such systems, the state of the system can change infinitely often in a finite time. This kind...

  12. Comparative Analysis of Two Proposed Models of Connecting rods for Crank-rocker Engines Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Mohammed Salah Eldin

    2014-07-01

    Full Text Available In this study, static load analysis was performed on two proposed models of connecting rods (conventional and Y-shape con-rod intended for use in the crank-rocker engine. The analysis was done by modeling the model using CATIA V5 software which was then analyzed using ANSYS Workbench 14.0 software. A static analysis was done to determine the von-misses stresses under tensile and compressive loading conditions. Two cases were studied, firstly, the load was applied at the rocker pin end and fixed at the crank end as a compressive load, and secondly, the load was applied at the same position as a tensile load with both cases under the same constant load. It was found from the analysis that the conventional connecting rod has yielded lower stress values for both cases as compared to the Y-shaped connecting rod. Based on the results, it was concluded that the normal connecting rod is better to be used for the crank-rocker engine.

  13. 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.

  14. 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.

  15. [Comparative analysis of action of beta-phenyl derivatives of glutamic and gamma-aminobutyric acid on cerebral blood flow and cerebrovascular endothelium after irreversible occlusion of the common carotid artery].

    Science.gov (United States)

    Volotova, E V; Kurkin, D V; Mazina, N V; Berestovitskaia, V M; Vasil'eva, O S

    2013-01-01

    A comparative analysis of the effect of phenyl derivatives of glutamic (RGPU-135) and gamma-aminobutyric acid (Phenibut) on cerebral blood flow, vasodilatory endothelial function and the number of circulating endothelial cells desquamated in animals after irreversible occlusion of the common carotid arteries. It was found that animals treated prophylactically by RGPU-135, after occlusion of the common carotid arteries have higher cerebral blood flow and lower the severity of endothelial dysfunction than in animals treated with Phenibut. PMID:24003482

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

    International Nuclear Information System (INIS)

    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.

  17. 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.

  18. Arterial Ageing

    OpenAIRE

    Lee, Seung-Jun; Park, Sung-Ha

    2013-01-01

    Arterial ageing is characterized by age associated degeneration and sclerosis of the media layer of the large arteries. However, besides ageing, clinical conditions, which enhance oxidative stress and inflammation act to accelerate the degree of arterial ageing. In this review, we summarized the pathophysiology and contributing factors that accelerate arterial ageing. Among them, we focused on hypertension, the renin-angiotensin-aldosterone system and vascular inflammation which are modifiabl...

  19. Curved Beam Computed Tomography based Structural Rigidity Analysis of Bones with Simulated Lytic Defect: A Comparative Study with Finite Element Analysis

    Science.gov (United States)

    Oftadeh, R.; Karimi, Z.; Villa-Camacho, J.; Tanck, E.; Verdonschot, N.; Goebel, R.; Snyder, B. D.; Hashemi, H. N.; Vaziri, A.; Nazarian, A.

    2016-09-01

    In this paper, a CT based structural rigidity analysis (CTRA) method that incorporates bone intrinsic local curvature is introduced to assess the compressive failure load of human femur with simulated lytic defects. The proposed CTRA is based on a three dimensional curved beam theory to obtain critical stresses within the human femur model. To test the proposed method, ten human cadaveric femurs with and without simulated defects were mechanically tested under axial compression to failure. Quantitative computed tomography images were acquired from the samples, and CTRA and finite element analysis were performed to obtain the failure load as well as rigidities in both straight and curved cross sections. Experimental results were compared to the results obtained from FEA and CTRA. The failure loads predicated by curved beam CTRA and FEA are in agreement with experimental results. The results also show that the proposed method is an efficient and reliable method to find both the location and magnitude of failure load. Moreover, the results show that the proposed curved CTRA outperforms the regular straight beam CTRA, which ignores the bone intrinsic curvature and can be used as a useful tool in clinical practices.

  20. Curved Beam Computed Tomography based Structural Rigidity Analysis of Bones with Simulated Lytic Defect: A Comparative Study with Finite Element Analysis.

    Science.gov (United States)

    Oftadeh, R; Karimi, Z; Villa-Camacho, J; Tanck, E; Verdonschot, N; Goebel, R; Snyder, B D; Hashemi, H N; Vaziri, A; Nazarian, A

    2016-01-01

    In this paper, a CT based structural rigidity analysis (CTRA) method that incorporates bone intrinsic local curvature is introduced to assess the compressive failure load of human femur with simulated lytic defects. The proposed CTRA is based on a three dimensional curved beam theory to obtain critical stresses within the human femur model. To test the proposed method, ten human cadaveric femurs with and without simulated defects were mechanically tested under axial compression to failure. Quantitative computed tomography images were acquired from the samples, and CTRA and finite element analysis were performed to obtain the failure load as well as rigidities in both straight and curved cross sections. Experimental results were compared to the results obtained from FEA and CTRA. The failure loads predicated by curved beam CTRA and FEA are in agreement with experimental results. The results also show that the proposed method is an efficient and reliable method to find both the location and magnitude of failure load. Moreover, the results show that the proposed curved CTRA outperforms the regular straight beam CTRA, which ignores the bone intrinsic curvature and can be used as a useful tool in clinical practices. PMID:27585495

  1. Embolization of the Gastroduodenal Artery Before Selective Internal Radiotherapy: A Prospectively Randomized Trial Comparing Standard Pushable Coils with Fibered Interlock Detachable Coils

    International Nuclear Information System (INIS)

    The purpose of this study was compare embolization of the gastroduodenal artery (GDA) using standard pushable coils with the Interlock detachable coil (IDC), a novel fibered mechanically detachable long microcoil, in patients scheduled for selective internal radiotherapy (SIRT). Fifty patients (31 male and 19 female; median age 66.6 ± 8.1 years) were prospectively randomized for embolization using either standard coils or IDCs. Procedure time, radiation dose, number of embolization devices, complications, and durability of vessel occlusion at follow-up angiography were recorded. The procedures differed significantly in time (14:32 ± 5:56 min for standard coils vs. 2:13 ± 1:04 min for IDCs; p < 0.001); radiation dose for coil deployment (2479 ± 1237 cGycm² for standard coils vs. 275 ± 268 cGycm² for IDCs; p < 0.001); and vessel occlusion (17:18 ± 6:39 min for standard coils vs. 11:19 ± 7:54 min for IDCs; p = 0.002). A mean of 6.2 ± 1.8 coils (n = 27) were used in the standard coil group, and 1.3 ± 0.9 coils (p < 0.0001) were used in the IDC group (n = 23) because additional pushable coils were required to achieve GDA occlusion in 4 patients. In 2 patients, the IDC could not be deployed through a Soft-VU catheter. One standard coil dislodged in the hepatic artery and was retrieved. Vessel reperfusion was noted in only 1 patient in the standard coil group. Controlled embolization of the GDA with fibered IDCs was achieved more rapidly than with pushable coils. However, vessel occlusion may not be obtained using a single device only, and the use of sharply angled guiding catheters hampered coil pushability.

  2. 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.

  3. All-ceramic and porcelain-fused-to-metal fixed partial dentures: a comparative study by 2D finite element analyses

    Directory of Open Access Journals (Sweden)

    Andréa Barreira Motta

    2007-10-01

    Full Text Available All-ceramic fixed partial dentures (FPDs have an esthetic approach for oral rehabilitation. However, metal-ceramic FPDs are best indicated in the posterior area where the follow-up studies found a lower failure rate. This 2D finite element study compared the stress distribution on 3-unit all-ceramic and metal-ceramic FPDs and identified the areas of major risk of failure. Three FPD models were designed: (1 metal-ceramic FPD; (2 All-ceramic FPD with the veneering porcelain on the occlusal and cervical surface of the abutment tooth; (3 All-ceramic FPD with the veneering porcelain only on the occlusal surface. A 100 N load was applied in an area of 0.5 mm² on the working cusps, following these simulations: (1 on the abutment teeth and the pontic; (2 only on the abutment teeth; and (3 only on the pontic. Relative to the maximum stress values found for the physiological load, all-ceramic FPD with only occlusal veneering porcelain produced the lowest stress value (220 MPa, followed by all-ceramic FPD with cervical veneering porcelain (322 MPa and metal-ceramic FPD (387 MPa. The stress distribution of the load applied on the abutments was significantly better compared to the other two load simulations. The highest principal stress values were low and limited in a small area for the three types of models under this load. When the load was applied on the pontic, the highest stress values appeared on the connector areas between the abutments and pontic. In conclusion, the best stress values and distribution were found for the all-ceramic FPD with the veneering porcelain only on the occlusal surface. However, in under clinical conditions, fatigue conditions and restoration defects must be considered.

  4. Finite Earth

    Science.gov (United States)

    2015-10-01

    The world has agreed on 17 Sustainable Development Goals, to be adopted this week. This is great progress towards acknowledging that the planet's finite resources need to be managed carefully in the face of humanity's unlimited aspirations.

  5. 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

    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...... by an attenuated systemic release of IL-8 (P = 0.041) and IL-10 (P = 0.006), while the release of IL-6 (P = 0.94), CRP (P = 0.121) and neutrophils (P = 0.078) did not differ between the groups. Indications of an uptake of cytokines in the lungs were found after OPCAB. Conclusions: When comparing OPCAB with CABG...

  6. COMPARATIVE EFFICACY OF LONG-TERM ANTIHYPERTENSIVE MONOTHERAPY IN PATIENTS WITH ARTERIAL HYPERTENSION AT THE WORK PLACE

    Directory of Open Access Journals (Sweden)

    О. N. Antropova

    2016-01-01

    Full Text Available Aim. To compare effects of 12-month monotherapy with nebivolol, enalapril and indapamide on blood pressure (BP, left ventricular hypertrophy and quality of life in the locomotive engineers and their assistants with stress-associated hypertension at the work place (HTwp.Material and methods. 96 locomotive engineers (20- 53 y.o and their assistants with HTwp were observed. The patients were randomized to receive nebivolol (1 group, enalapril (2 group or indapamide (3 group. 24-hour BP monitoring, echocardiography and quality of life interview with SF–36 questionnaire were performed at the start and after 12 months of the treatment.Results. Long-term therapy lead to achievement of target BP level, improved quality of life and reduced in left ventricular hypertrophy in patients with HTwp. Nebivolol reduced systolic “BP load” more significantly than indapamide did, exerted favorable influence on circadian BP rhythm and reduced heart rate. Monotherapy with nebivolol showed benefits in effect on quality of life.Conclusion. Nebivolol has some advantages in comparison with indapamide and enalapril in antihypertensive therapy of patients with stress-associated HT.

  7. 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.

  8. 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.

  9. Decision making in the treatment of peripheral arterial disease - A single-institution comparative study using information from color doppler and digital subtraction angiogram studies

    Directory of Open Access Journals (Sweden)

    Chiramel G Koshy

    2011-01-01

    Full Text Available Background: Numerous studies have compared the accuracy of color Doppler (CD with that of digital subtraction angiography (DSA in the diagnosis of peripheral arterial disease (PAD. However, only a few have looked at the influence of these diagnostic tests on the treatment decision in PAD. Aim: This study evaluated the differences in treatment decisions that were based on CD and with those based on DSA findings. Methods and Materials: Findings from CD and DSA studies obtained in 40 patients were entered on line diagrams by two radiologists working separately. These were randomized and sent to three experienced clinicians - two vascular surgeons and one interventional radiologist. The treatment decisions of the clinicians based on each proforma were collected and analyzed to look for the degree of agreement between Doppler-based and DSA-based decisions. Results: There was fair to moderate agreement between CD-based and DSA-based decisions for all three clinicians, with some improvement in agreement with the addition of clinical data. The vascular surgeons showed better agreement with each other on treatment decisions compared to the interventional radiologist who showed a fair-to-moderate level of agreement with the vascular surgeons, which did not significantly change with the addition of clinical data. Conclusion: There is a fair to moderate agreement between treatment decisions based on CD findings and those based on DSA findings. We conclude that CD along with clinical data is sufficient to make decisions in the treatment of PAD.

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

    Directory of Open Access Journals (Sweden)

    P.L. da Luz

    2011-10-01

    Full Text Available 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.

  11. 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.

  12. Comparative measurement of silicon and major elements (P,S,Cl,K,Ca) in arterial walls using macro and microbeam analysis

    International Nuclear Information System (INIS)

    There are few techniques available for the measurement of silicon at trace levels in biological materials. PIXE and prompt nuclear reaction analysis were used to locate and measure silicon and major elements in arterial walls. Macrobeam analysis, carried out by the Van de Graaff accelerator at CENBG, enabled measurement of mean tissue levels. Microbeam analysis, using the nuclear microprobe at Karlsruhe, yielded the distribution of these elements through the thickness of the arterial wall. The microanalyses were performed on arterial walls from healthy rabbits and the macrobeam study was carried out on the same samples and also on human aorta specimens

  13. 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.

  14. Experimental Embolization of Rabbit Renal Arteries to Compare the Effects of Poly L-Lactic Acid Microspheres With and Without Epirubicin Release Against Intraarterial Injection of Epirubicin

    International Nuclear Information System (INIS)

    Purpose: We performed a basic investigation using white rabbits of the sustained release and embolizing effects of poly L-lactic acid microspheres (PLA) to determine their usefulness for chemoembolization.Methods: Fifteen male Japanese white rabbits were used. Sustained release of an embolizing material, EPI-PLA was accomplished with 1 mg of PLA containing 0.03 mg of epirubicin hydrochloride (EPI). Embolization with 50 mg of PLA (total dose of EPI 1.5 mg) was performed after the renal artery of the rabbits was selected (Chemo-TAE group). A group in which a bolus of 1.5 mg EPI alone was injected through the renal artery (TAI group) was established as a control group. Furthermore, a group in which embolization was performed with 50 mg of PLA alone (TAE group) was also established. These three groups, each consisting of five rabbits, were compared.Results: Blood EPI levels were serially measured. The blood EPI level in the TAI group rapidly reached a peak more than 30 min after injection, then decreased to almost zero 24 hr after injection. In the Chemo-TAE group, the blood EPI level was transiently increased 30 min after embolization, but remained low thereafter until 24 hr after embolization. EPI levels in kidney tissue isolated 24 hr after embolization were measured. In the Chemo-TAE group, the tissue EPI level was significantly higher than that in the TAI group. When isolated kidneys were macroscopically and histologically examined, atrophy of the entire embolized kidney, as well as infarction and necrosis in the renal cortex, were observed in both the TAE group and the Chemo-TAE group. However, there were no such findings in the TAI group. The area of the infarction in the renal cortex did not significantly differ between the Chemo-TAE group and the TAE group; however, there was vascular injury in the Chemo-TAE group and none in the TAE group.Conclusion: It was demonstrated that EPI-PLA, a chemoembolizing material, maintained high local concentrations of the

  15. Experimental embolization of rabbit renal arteries to compare the effects of poly L-lactic acid microspheres with and without epirubicin release against ntraarterial injection of epirubicin

    International Nuclear Information System (INIS)

    Purpose: We performed a basic investigation using white rabbits of the sustained release and embolizing effects of poly L-lactic acid microspheres (PLA) to determine their usefulness for chemoembolization.Methods: Fifteen male Japanese white rabbits were used. Sustained release of an embolizing material, EPI-PLA was accomplished with l m g of PLA containing 0.03 mg of epirubicin hydrochloride (EPI). Embolization with 50 mg of PLA (total dose of EPI l.5 mg) was performed after the renal artery of the rabbits was selected (Chemo-TAE group). A group in which a bolus of 1.5 mg EPI alone was injected through the renal artery (TAI group) was established as a control group. Furthermore, a group in which embolization was performed with 50 mg of PLA alone (TAE group) was also established. These three groups, each consisting of five rabbits, were compared.Results: Blood EPI levels were serially measured. The blood EPI level in the TAI group rapidly reached a peak more than 30 min after injection, then decreased to almost zero 24 hr after injection. In the Chemo-TAE group, the blood EPI level was transiently increased 30 min after embolization, but remained low thereafter until 24 hr after embolization. EPI levels in kidney tissue isolated 24 hr after embolization were measured. In the Chemo-TAE group, the tissue EPI level was significantly higher than that in the TAI group. When isolated kidneys were macroscopically and histologically examined, atrophy of the entire embolized kidney, as well as infarction and necrosis in the renal cortex, were observed in both the TAE group and the Chemo-TAE group. However, there were no such findings in the TAI group. The area of the infarction in the renal cortex did not significantly differ between the Chemo-TAE group and the TAE group; however, there was vascular injury in the Chemo-TAE group and none in the TAE group.Conclusion: It was demonstrated that EPI-PLA, a chemo-embolizing material, maintained high local concentrations of the

  16. 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

  17. Quantitative and qualitative assessment of non-obstructive left main coronary artery plaques using 64-multislice computed tomography compared with intravascular ultrasound

    Institute of Scientific and Technical Information of China (English)

    SHEN Yi; QIAN Ju-ying; WANG Ming-hui; LIU Yuan; LIU Xue-bo; GE Lei; MA Jian-ying; GE Jun-bo

    2010-01-01

    Background There are few reports of quantitative and qualitative measuring of left main coronary artery (LMCA) plaques by multislice computed tomography coronary angiography (MSCTA), especially when compared with intravascular ultrasound (IVUS) as reference standard. The aim of this study was to evaluate the use of 64-MSCTA in the diagnosis of LMCA disease, and the accuracy of MSCTA in the quantitative and qualitative assessment of the LMCA lesion as compared with IVUS.Methods A total of 91 patients (53 men, 38 women, mean age (64.78±9.19) years) were examined by 64-MSCTA and IVUS. Compared with the IVUS, the sensitivity, specificity, positive and negative predictive values (PPV and NPV) of the MSCTA on the diagnosis of LMCA diseases were calculated. Also, kappa index (K) for the agreement between MSCTA and IVUS was calculated. Minimal lumen area (MLA), external elastic membrane cross-sectional area (EEM-CSA) and plaque burden were measured by two blinded and independent operators on MSCTA cross-sectional reconstruction and compared with the parameters measured from IVUS by manually tracing. The CT value of soft, fibrous and calcific plaques was measured using IVUS classification of the plaques.Results The sensitivity, specificity, PPV and NPV of MSCTA for detecting LMCA plaques were 93.1%, 84.2%, 95.7%, 76.2%, respectively. Kappa index (K=0.744, P<0.001) indicated excellent agreement between MSCTA and IVUS. The Pearson index between MLA on IVUS and MLA on MSCTA was 0.815 (P <0.01). The Pearson index of plaque burden and EEM-CSA between IVUS and MSCTA was 0.736 and 0.740 respectively (both P <0.01). The CT value of soft plaque, fibrous plaque and calcific plaque compared with IVUS were (52.52±15.71) HU, (108.32±43.44) HU and (604.16±377.67) HU (P<0.001). Receiver operating characteristic curve analysis of CT value of non-calcific plaques for predicting soft plaques showed the cutpoint was 54.35 HU, with a sensitivity of 83.3% and specificity of 94

  18. 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.

  19. 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.

  20. 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

  1. A comparative study on inhibition of total astragalus saponins and astragaloside IV on TNFR1-mediated signaling pathways in arterial endothelial cells.

    Directory of Open Access Journals (Sweden)

    Qin-she Liu

    Full Text Available BACKGROUND: Both total astragalus saponins (AST and it's main component astragaloside IV (ASIV have been used in China as cardiovascular protective medicines. However, the anti-inflammatory activities that are beneficial for cardiovascular health have never been compared directly and the molecular mechanisms remain unresolved. This study was conducted to compare the inhibitory effects of these drugs on TNFα-induced cell responses, related signaling pathways, and the underlying mechanisms in mouse arterial endothelial cells. METHODOLOGY/PRINCIPAL FINDINGS: Real-time qRT-PCR was performed to determine the expression of cell adhesion molecule (CAM genes. Immunofluorescent staining was used to detect the nuclear translocation of transcription factor NF-κB-p65. Western Blot analysis was used to identify TNFα-induced NF-κB-p65 phosphorylation, IκBα degradation, and caspase-3 cleavage. Cell surface proteins were isolated and TNFα receptor-1(TNFR1 expression was determined. The results suggest that both AST and ASIV attenuate TNFα-induced up-regulation of CAMs mRNA and upstream nuclear translocation and phosphorylation of NF-κB-p65. However, TNFR1-mediated IκBα degradation, cleavage of caspase-3 and apoptosis were inhibited only by AST. These differences in the actions of AST and ASIV could be explained by the presence of other components in AST, such as ASII and ASIII, which also had an inhibitory effect on TNFR1-induced IκBα degradation. Moreover, AST, but not ASIV, was able to reduce TNFR1 protein level on the cell surface. Furthermore, mechanistic investigation demonstrated that TNFR1-mediated IκBα degradation was reversed by the use of TAPI-0, an inhibitor of TNFα converting enzyme (TACE, suggesting the involvement of TACE in the modulation of surface TNFR1 level by AST. CONCLUSION: ASIV was not a better inhibitor than AST, at least on the inhibition of TNFα-induced inflammatory responses and TNFR1-mediated signaling pathways in

  2. 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.

  3. 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

    We examine various independent component analysis (ICA) digital signal processing algorithms for estimating the arterial oxygen saturation (SpO2) as measured by a reflective pulse oximeter. The ICA algorithms examined are FastICA, Maximum Likelihood ICA (ICAML), Molgedey and Schuster ICA (ICAMS...

  4. 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.

  5. 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).

  6. 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 ...

  7. 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

  8. 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

  9. Carotid Artery Screening

    Science.gov (United States)

    ... Resources Professions Site Index A-Z Carotid Artery Screening What is carotid artery screening? Who should consider ... about carotid artery screening? What is carotid artery screening? Screening examinations are tests performed to find disease ...

  10. 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.

  11. 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.

  12. Accurate Finite Difference Algorithms

    Science.gov (United States)

    Goodrich, John W.

    1996-01-01

    Two families of finite difference algorithms for computational aeroacoustics are presented and compared. All of the algorithms are single step explicit methods, they have the same order of accuracy in both space and time, with examples up to eleventh order, and they have multidimensional extensions. One of the algorithm families has spectral like high resolution. Propagation with high order and high resolution algorithms can produce accurate results after O(10(exp 6)) periods of propagation with eight grid points per wavelength.

  13. $\\delta$-Expansion at Finite Temperature

    OpenAIRE

    Ramos, Rudnei O.

    1996-01-01

    We apply the $\\delta$-expansion perturbation scheme to the $\\lambda \\phi^{4}$ self-interacting scalar field theory in 3+1 D at finite temperature. In the $\\delta$-expansion the interaction term is written as $\\lambda (\\phi^{2})^{ 1 + \\delta}$ and $\\delta$ is considered as the perturbation parameter. We compute within this perturbative approach the renormalized mass at finite temperature at a finite order in $\\delta$. The results are compared with the usual loop-expansion at finite temperature.

  14. 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.)

  15. 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.

  16. Locally Finite Root Supersystems

    OpenAIRE

    YOUSOFZADEH, Malihe

    2013-01-01

    We introduce the notion of locally finite root supersystems as a generalization of both locally finite root systems and generalized root systems. We classify irreducible locally finite root supersystems.

  17. 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.

  18. [COMPARATIVE CEREBROPROTECTIVE EFFECT OF PREVENTIVE ADMINISTRATION OF MAGNESIUM HYDROXYBUTYRATE VERSUS MAGNESIUM SULFATE AND CAVINTON IN RATS WITH COMMON CAROTID ARTERY OCCLUSION].

    Science.gov (United States)

    Tyurenkov, I N; Litvinov, A A; Kurkin, D V; Volotova, E V; Darmanyan, A P; Ozerov, A A

    2016-01-01

    Dose-dependent cerebroprotective effect of magnesium hydroxybutyrate (MHB) on common carotid artery occlusion model in rats was established. Administration of 150 mg/kg MHB led to significant decrease in animal mortality (up to 9.3 times) in comparison to control (p McGraw scale in comparison to control and magnesium sulfate (50% and 20%, respectively). The MHB treated animals also showed improved locomotor and exploratory performance in the open-field test and retained memory performance in the passive avoidance test and extrapolation escape task test. The administration of 150 mg/kg MHB produced three-fold (p < 0.05) decrease of brain edema in animals with cerebral blood flow impairment in comparison to animals treated with magnesium sulfate and cavinton. PMID:27455571

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

    OpenAIRE

    Serruys, Patrick; Morice, Marie-Claude; Kappetein, Arie Pieter; Colombo, Antonio; Holmes, David; Mack, Michael; Stahle, E.; Feldman, Ted; Brand, Marcel, van den; Bass, Eric; Dyck, Nic; Leadly, Katrin; Dawkins, Keith; 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 patients with previously untreated three-vessel or left main coronary artery disease (or both). METHODS We randomly assigned 1800 patients with three-vessel or left main coronary artery disease to und...

  20. A STUDY ON THE PATTERNS OF CIRCUMFLEX FEMORAL ARTERIES

    Directory of Open Access Journals (Sweden)

    R. Chitra

    2015-09-01

    Full Text Available Context: Many different patterns have been described to classify the origins of circumflex femoral arteries by many authors since from 1860.The aim of the present study was to classify the circumflex femoral arteries in 100 lower limbs of adult cadavers of both sexes following the recent classification and to compare with the previous studies. Materials and Methods: A total of 100 lower limbs of 50 embalmed human adult cadavers (Male: 37, Female: 13 were dissected and observed for the origins of circumflex femoral arteries in femoral triangle in routine educational dissection in the period of 2005-2009 Results: The medial and lateral circumflex femoral arteries have been classified into three different patterns based on the levels of their origin. Pattern I: Both arteries arose from the profunda femoris artery (56%. Type Ia, medial circumflex femoral artery origin was proximal to the lateral circumflex femoral artery origin (69%; Type Ib, lateral circumflex femoral artery origin was proximal to medial circumflex femoral artery origin (16 %; Type Ic, both arteries arose from a common trunk or at same level (14%. Pattern II: One of the arteries arose from the femoral artery and the other from the profunda femoris artery (36%. Type IIa, the medial circumflex femoral artery arose from the femoral artery (75% and Type IIb, the lateral circumflex femoral artery arose from the femoral artery (25%.Pattern III: Both arteries arose from the femoral artery (7%. The medial circumflex femoral artery was absent in a female cadaver on right side. Conclusion: In every pattern or type, there was significantly unilateral higher occurrence than bilateral occurrence. A precise knowledge of the circumflex femoral arteries in relation to the profunda femoris artery is important in surgical interventions of the hip region

  1. Angioplasty and stent placement -- peripheral arteries

    Science.gov (United States)

    Percutaneous transluminal angioplasty - peripheral artery; PTA - peripheral artery; Angioplasty - peripheral arteries; Iliac artery -angioplasty; Femoral artery - angioplasty; Popliteal artery - angioplasty; Tibial ...

  2. A non-Newtonian fluid model for blood flow through arteries under stenotic conditions.

    Science.gov (United States)

    Misra, J C; Patra, M K; Misra, S C

    1993-09-01

    This paper presents an analytical study on the behaviour of blood flow through an arterial segment having a mild stenosis. The artery has been treated as a thin-walled initially stressed orthotropic non-linear viscoelastic cylindrical tube filled with a non-Newtonian fluid representing blood. The analysis is restricted to propagation of small-amplitude harmonic waves, generated due to blood flow whose wave length is large compared to the radius of the arterial segment. For the equations of motion of the arterial wall consideration is made of a pair of appropriate equations derived by using suitable constitutive relations and the principle of superimposition of a small additional deformation on a state of known finite deformation. It has been shown through numerical computations of the resulting analytical expressions that the resistance to flow and the wall shear increase as the size of the stenosis increases. A quantitative analysis is also made for the frequency variation of the flow rate at different locations of the artery, as well as of the phase velocities and transmission per wavelength.

  3. Carotid Artery Disease

    Science.gov (United States)

    ... brain with blood. If you have carotid artery disease, the arteries become narrow, usually because of atherosclerosis. ... one of the causes of stroke. Carotid artery disease often does not cause symptoms, but there are ...

  4. 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 ...

  5. 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.

  6. 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.

  7. Evaluation of contrast-enhanced magnetic resonance angiography (MRA) using Gd-DOTA compared with time-of-flight MRA in the diagnosis of clinically significant non-coronary arterial disease

    International Nuclear Information System (INIS)

    This trial assessed diagnostic accuracy of contrast-enhanced magnetic resonance angiography (MRA) with meglumine gadoterate (Gd-DOTA) at 3 Tesla (T) over unenhanced MRA at 3 T in non-coronary arterial diseases by comparing their accuracy with that of the gold standard, x-ray angiography. Ninety-two patients with suspected non-coronary arterial disease underwent in fixed sequence unenhanced time-of flight (TOF) MRA, contrast-enhanced MRA using a Gd-DOTA bolus (intravenous bolus 0.1 mmol/kg) and x-ray angiography. Eighty-four patients (71 male, 13 female; median age 64.5 years) were included in an intent-to-treat efficacy analysis. Targeted vascular areas were aorto-iliac, calf, carotid, femoral, popliteal and renal. Within-patient accuracy was significantly higher with contrast-enhanced MRA using Gd-DOTA than with unenhanced MRA (p = 0.0003). There was 84.4 ± 17.5% agreement between contrast-enhanced MRA (Gd-DOTA) and x-ray angiography, compared with 76.8 ± 20.4% between non-enhanced MRA and x-ray angiography. Sensitivity and specificity were also better with Gd-DOTA compared with non-enhanced MRA at the segment level. Duration of the MRA procedure was 3.5 times shorter with Gd-DOTA compared with non-enhanced MRA. Six patients reported six mild or moderate adverse events. No serious adverse events occurred. Contrast-enhanced MRA using Gd-DOTA at 3 T was superior to unenhanced TOF MRA in the vascular territories investigated. (orig.)

  8. 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.)

  9. 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

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

    International Nuclear Information System (INIS)

    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 10-3 mm2/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.)

  11. 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...

  12. Early outcomes of laparoscopic donor nephrectomy with multiple renal arteries

    Directory of Open Access Journals (Sweden)

    Fernando Meyer

    2012-08-01

    Full Text Available PURPOSE: We evaluated our experience with laparoscopic donor nephrectomy in patients with multiple renal arteries, comparing operative outcomes and early graft function with patients with a single renal artery. MATERIALS AND METHODS: From January 2003 to February 2009, 130 patients underwent laparoscopic donor nephrectomy at our institution, 108 (83% with a single renal artery and 22 (17% with multiple arteries. Donor and recipient outcomes for single artery and multiple arteries allografts were compared. RESULTS: The LDN operative time was similar between the single artery and multiple arteries groups (162 vs 163 min, respectively, p = 0.87. Allografts with multiple arteries had significantly longer warm ischemia time (3.9 vs 4.9 min, p = 0.05 and cold ischemia time (72 vs 94 min, p < 0.001 than those with single artery. The conversion rate was similar between single and multiple arteries groups (6% vs 4.5%, respectively, p = 0.7. Multiple arteries grafts had a non statistically significant higher rate of poor graft function when compared to single artery grafts (23% vs 12%, respectively, p = 0.18. Five patients in the single artery group (4.6% and one patient in the multiple arteries group (4.5% needed dialysis during the first postoperative week. Overall, recipient complication rates were similar between single and multiple arteries groups (12.9% vs 18.1%, respectively, p = 0.51. CONCLUSION: Laparoscopic donor nephrectomy with multiple arteries was associated with a non statistically significant higher rate of poor early graft function. The procedure appears to be safe in patients with multiple arteries, with similar complications rates. Multiple arteries should not be a contraindication for laparoscopic donor nephrectomy.

  13. 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

  14. 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.

  15. 经左桡动脉与右桡动脉入路冠状动脉造影术安全性和有效性比较%Safety and efficiency of coronary angiography via left radial artery compared with right radial artery ap-proach

    Institute of Scientific and Technical Information of China (English)

    聂斌; 张维君; 杨清; 马涵英; 王建龙; 周玉杰

    2012-01-01

    目的 探讨经左桡动脉行冠状动脉造影术的安全性和有效性.方法 将463例择期行冠状动脉造影术的患者完全随机分入左桡动脉入路组(231例)和右桡动脉入路组(232例).比较2组患者手术成功率、手术时间、X线透视时间、对比剂用量、单导管技术成功率、血管并发症发生率等.结果 左桡动脉入路组手术成功率98.3%(227/231),右桡动脉入路组手术成功率97.4%(226/232),组间差异无统计学意义(P>0.05).2组手术时间、X线透视时间、对比剂用量、血管并发症发生率、单导管技术成功率等均相似,差异均无统计学意义(均P>0.05).结论 经左桡动脉入路行冠状动脉造影有着与右桡动脉入路相似的成功率和安全性,左桡动脉入路单导管技术完全可行,并且在头臂干迂曲患者中有优势.%Objective To explore the efficiency and safety of coronary angiography (CA)via left radial artery compared with right radial artery approach.Methods All 463 consecutive patients undergoing elective CA were randomized divided into left radial artery group (L-TRA,231 cases)and right radial artery group (R-TRA,232 cases).The study endpoints included procedure success rate,procedure duration,fluoroscopy time,consumption of contrast media,success rate of single catheter technique and vascular related complications.Results Both L-TRA and R-TRA group had similarly high procedure success rate [98.3% (227/231)vs 97.4% (226/232)],and there was no significant difference(P > 0.05).Regarding procedure duration,fluoroscopy time,contrast media dosage,success rate of single catheter and vascular complications,two groups had no significant diffrernce(P >0.05).Conclusions Left radial artery approach has similar safety and efficiency in terms of performing CA compared to right RA.The single catheter technique is feasible in left RA approach.

  16. A case-controlled evaluation of the Medtronic Resting Heart System compared with conventional cardiopulmonary bypass in patients undergoing isolated coronary artery bypass surgery†

    OpenAIRE

    Nozohoor, Shahab; Johnsson, Per; Scicluna, Sara; Wallentin, Per; Andell, Elisabeth; Nilsson, Johan

    2012-01-01

    The Medtronic Resting Heart System (RHS) is a heparin-coated, closed perfusion circuit. Clinical results indicate less haemodilution and reduced complement activation, when compared with a traditional circuit leading to fewer postoperative blood transfusions. We evaluated the potential clinical benefits, including reduced transfusion requirements, when using the RHS compared with conventional cardiopulmonary bypass (cCPB). The study group (n = 330) consisted of patients undergoing isolated co...

  17. 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.

  18. Finite Pluricomplex energy measures

    OpenAIRE

    Di Nezza, Eleonora

    2015-01-01

    We investigate probability measures with finite pluricomplex energy. We give criteria insuring that a given measure has finite energy and test these on various examples. We show that this notion is a biholomorphic but not a bimeromorphic invariant.

  19. 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

  20. 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

  1. 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

    -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%: 55-61) yielded a lower specificity. CONCLUSIONS: In this meta-analysis comparing cardiac imaging methods directly to FFR, MRI had the highest performance for diagnosis of ischaemia-causing......), 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...

  2. 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.

  3. 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.

  4. 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.

  5. Computational analysis of anterior communicating artery aneurysm shear stress before and after aneurysm formation

    Science.gov (United States)

    Castro, Marcelo A.; Putman, Christopher M.; Cebral, Juan R.

    2011-12-01

    It is widely accepted that complexity in the flow pattern at the anterior communicating artery (AComA) is associated with the high rate of aneurysm formation at that location observed in large studies. The purpose of this work is to study associations between hemodynamic patterns, and AComA aneurysm initiation by comparing hemodynamics in the aneurysm and the normal model where the aneurysm was computationally removed. Vascular models of both right and left circulation were independently reconstructed from three-dimensional rotational angiography images using deformable models after image registration of both images, and fused using a surface merging algorithm. The geometric models were then used to generate high-quality volumetric finite element grids of tetrahedra with an advancing front technique. For each patient, the second anatomical model was created by digitally removing the aneurysm. It was iteratively achieved by applying a Laplacian smoothing filter and remeshing the surface. Finite element blood flow numerical simulations were performed for both the pathological and normal models under the same personalized pulsatile flow conditions imposed at the inlets of both models. The Navier-Stokes equations were numerically integrated by using a finite-element formulation. It was observed that aneurysms initiated in regions of high and moderate WSS in the counterpart normal models. Adjacent or close to those regions, low WSS portions of the arterial wall were not affected by the disease. These results are in line with previous observations at other vascular locations.

  6. A classification of finite quantum kinematics

    International Nuclear Information System (INIS)

    Quantum mechanics in Hilbert spaces of finite dimension N is reviewed from the number theoretic point of view. For composite numbers N possible quantum kinematics are classified on the basis of Mackey's Imprimitivity Theorem for finite Abelian groups. This yields also a classification of finite Weyl-Heisenberg groups and the corresponding finite quantum kinematics. Simple number theory gets involved through the fundamental theorem describing all finite discrete Abelian groups of order N as direct products of cyclic groups, whose orders are powers of not necessarily distinct primes contained in the prime decomposition of N. The representation theoretic approach is further compared with the algebraic approach, where the basic object is the corresponding operator algebra. The consideration of fine gradings of this associative algebra then brings a fresh look on the relation between the mathematical formalism and physical realizations of finite quantum systems

  7. A Bayesian Bootstrap for a Finite Population

    OpenAIRE

    Lo, Albert Y.

    1988-01-01

    A Bayesian bootstrap for a finite population is introduced; its small-sample distributional properties are discussed and compared with those of the frequentist bootstrap for a finite population. It is also shown that the two are first-order asymptotically equivalent.

  8. 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.

  9. 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....

  10. 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.

  11. Mixed finite element-finite volume methods

    OpenAIRE

    Zine Dine, Khadija; Achtaich, Naceur; Chagdali, Mohamed

    2010-01-01

    This paper is devoted to present a numerical methods for a model of incompressible and miscible flow in porous media. We analyze a numerical scheme combining a mixed finite element method (MFE) and finite volume scheme (FV) for solving a coupled system includes an elliptic equation (pressure and velocity) and a linear convection-diffusion equation (concentration). The (FV) scheme considered is "vertex centered" type semi implicit. We show that this scheme is $L^{\\infty...

  12. [Abnormal popliteal arteries].

    Science.gov (United States)

    Elbaz, C

    1975-01-01

    Arteriopathy restricted to the popliteal artery, except in cases of atheroma, must indicate three of four unusual diagnoses: the trapped popliteal artery and the dessicating haematoma are anatomo-clinical entities that have been identified only relatively recently. The popliteal artery may be trapped by the medial gastrocnomius muscle, round the tendon of which the artery passes (totally or partially). This results in compression of the artery and eventually in thrombosis. Clinically, intermittent claudication is seen that may deteriorate and lead to gangrene of the toes. Arteriography makes it possible to diagnose the condition as the condition as the artery is considerably displaced inwards. Surgical correction is simple: sectioning of the tendon and repositioning of the artery. Dessicating haematoma of the popliteal artery is due essentially to atheroma, associated with medianecrosis. A "egg-timer" stenosis is found by arteriography and this condition also progresses towards thrombosis. Arterial restoration is called for, usually by bridging. PMID:1230799

  13. 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.

  14. Duplex ultrasound scanning of peripheral arterial disease of the lower limb

    DEFF Research Database (Denmark)

    Eiberg, Jonas Peter; Rasmussen, John Bøje Grønvall; Hansen, Marc Allan;

    2010-01-01

    To assess the reliability and applicability of duplex ultrasound scanning (DUS) of lower limb arteries, compared with digital subtraction angiography (DSA), in patients with peripheral arterial disease (PAD).......To assess the reliability and applicability of duplex ultrasound scanning (DUS) of lower limb arteries, compared with digital subtraction angiography (DSA), in patients with peripheral arterial disease (PAD)....

  15. The comparative analysis of the two dimensional Laplace equation using the Galerkin finite element method with the exact solution for various domains (circular and rectangular with triangular elemental meshing

    Directory of Open Access Journals (Sweden)

    Sarah Balkissoon

    2015-02-01

    Full Text Available Laplace Equation is used in many areas of studies such as potential theory and the fundamental forces of nature, Newtonian theory of gravity and electrostatics. It is used in Probability theory and Markov Chains as well as potential flows in fluid mechanics. Laplace Equation is used in various research areas and for this reason, to determine an accurate solution to this equation is of importance. In this study, the Finite Element Method is used to approximate the solution of the 2D Laplace Equation for two regions, circular and rectangular domains. These are compared to the exact solutions of the systems subjected to various physical restrictions; boundary conditions. This was done by using a mesh generator in Matlab, Distmesh, to obtain a mesh of triangular elements and then using Matlab to plot the exact and the approximated solutions as well as to determine the errors;   norm. For these domains, the number of elements in the mesh was incremented and it was noted there was a convergence of the approximated to the actual solution. The boundary conditions were altered to observe the changes in the regions' field variable distribution (intensity values of the Matlab plots.

  16. Comparative study of percutaneous coronary intervention via transradial artery and transfemoral artery in the treatment of coronary artery disease%经桡动脉与股动脉两种路径介入治疗冠心病的对比研究

    Institute of Scientific and Technical Information of China (English)

    谢静; 郑时康; 王甲文; 祝鹏; 任晖; 刘胜强; 马晶晶; 刘菲; 周俊; 宋大坤; 屈兰燕

    2013-01-01

    目的 探讨经桡动脉路径行经皮冠状动脉介入治疗的优越性.方法 回顾分析经皮冠状动脉介入治疗的423 例冠心病患者资料,其中经桡动脉路径组213 例(观察组),经股动脉路径组210 例(对照组),比较两组间首次穿刺置管成功率、手术成功率、平均住院天数及术后并发症的发生率.结果 观察组与对照组首次穿刺置管成功率(96.8% vs 98.7%)、手术成功率(98.2% vs 99.0%)比较差异无统计学意义(P>0.05);平均住院天数[(6.12±0.67) d vs (9.02±0.81) d]、局部血肿(2/12)、尿潴留(0/18)、失眠(2/20)、烦躁(3/14)及并发症的总发生率(5.6%vs 37.1%)比较差异有统计学意义(P0.05. Statistically significant difference was found between the two groups in the mean length of hospital stay [(6.12±0.67) vs (9.02±0.81)], the incidence of local hematoma (2 vs 12), urinary retention (0 vs 18), insomnia (2 vs 20), irritability (3 vs 14), the total incidence of postoperative complications (5.6% vs 37.1%), P<0.05. Conclusion Percutaneous coronary intervention via transradial artery was safe and feasible, which should be the first choice for treating coronary artery disease.

  17. 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.

  18. 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. PMID:26341795

  19. [A comparative evaluation of the importance of transesophageal electrical stimulation of the left atrium and of bicycle ergometry in the diagnosis of ischemic heart disease in patients with arterial hypertension].

    Science.gov (United States)

    Azizov, V A; Gorshkov, A Sh; Kivaeva, G M; Gadzhiev, R Sh; Bekzhigitov, S B; Arabidze, G G; At'kov, O Iu

    1992-07-01

    To make a comparative assessment of transesophageal left atrial pacing (TLAP) and bicycle ergometry (BE) in the diagnosis of coronary heart disease (CHD) in patients with arterial hypertension (AH) of different origin, the authors examined 56 patients. The patients underwent TLAP and selective coronary angiography, of them 39 patients had BE testing. No significant differences were found in their specificity (73 and 78%) and sensitivity (92 and 81%) between TLAP and BE, respectively. The maximum heart rate in CHD patients with AH was significantly higher (130 +/- 6 per min) during TLAP than that in BE (112 +/- 5 per min, p > 0.05), ischemic changes occurring at the same value of double product despite the mode of myocardial ischemia induction in these functional tests (240 +/- 10 and 236 +/- 12 arbitrary units, respectively; p < 0.05). The mean systolic blood pressure was higher in TLAP and in BE (210 +/- 10 and 185 +/- 8 mm Hg). This follows that TLAP and BE finding are comparable and no profound changes occur in TLAP, hence it can be recommended for wide application in the diagnosis of CHD in AH patients. PMID:1487876

  20. On the Compressibility of Arterial Tissue.

    Science.gov (United States)

    Nolan, D R; McGarry, J P

    2016-04-01

    Arterial tissue is commonly assumed to be incompressible. While this assumption is convenient for both experimentalists and theorists, the compressibility of arterial tissue has not been rigorously investigated. In the current study we present an experimental-computational methodology to determine the compressibility of aortic tissue and we demonstrate that specimens excised from an ovine descending aorta are significantly compressible. Specimens are stretched in the radial direction in order to fully characterise the mechanical behaviour of the tissue ground matrix. Additionally biaxial testing is performed to fully characterise the anisotropic contribution of reinforcing fibres. Due to the complexity of the experimental tests, which entail non-uniform finite deformation of a non-linear anisotropic material, it is necessary to implement an inverse finite element analysis scheme to characterise the mechanical behaviour of the arterial tissue. Results reveal that ovine aortic tissue is highly compressible; an effective Poisson's ratio of 0.44 is determined for the ground matrix component of the tissue. It is also demonstrated that correct characterisation of material compressibility has important implications for the calibration of anisotropic fibre properties using biaxial tests. Finally it is demonstrated that correct treatment of material compressibility has significant implications for the accurate prediction of the stress state in an artery under in vivo type loading. PMID:26297340

  1. 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.

  2. 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.

  3. Combination of Rare Right Arterial Variation with Anomalous Origins of the Vertebral Artery, Aberrant Subclavian Artery and Persistent Trigeminal Artery

    Science.gov (United States)

    Ishihara, H.; San Millán Ruíz, D.; Abdo, G.; Asakura, F.; Yilmaz, H.; Lovblad, K.O.; Rüfenacht, D.A.

    2011-01-01

    Summary A 32-year-old woman hospitalized for subarachnoid hemorrhage showed rare arterial variation on the right side with anomalous origins of the vertebral artery, aberrant subclavian artery and persistent trigeminal artery. Angiography showed the right vertebral artery to originate from the right common carotid artery, the right subclavian artery to arise separately from the descending aorta, and persistent trigeminal artery on the right side. The possible embryonic mechanism of this previously unreported variant combination is discussed. PMID:22005696

  4. On Renal Artery Stenosis

    OpenAIRE

    Eklöf, Hampus

    2005-01-01

    Renal artery stenosis (RAS) is a potentially curable cause of hypertension and azotemia. Besides intra-arterial renal angiography there are several non-invasive techniques utilized to diagnose patients with suspicion of renal artery stenosis. Removing the stenosis by revascularization to restore unobstructed blood flow to the kidney is known to improve and even cure hypertension/azotemia, but is associated with a significant complication rate. To visualize renal arteries with x-ray technique...

  5. Vertebral artery aneurysms.

    Directory of Open Access Journals (Sweden)

    Ravi Kumar C

    2000-04-01

    Full Text Available Vertebral artery (VA aneurysms are rare. We present our experience with three cases of VA aneurysms. Two aneurysms were located close to the origin of basilar artery while the third patient had a giant posterior inferior cerebellar artery aneurysm. These aneurysms were operated by the far lateral inferior suboccipital approach with good results.

  6. Retinal artery occlusion

    Science.gov (United States)

    ... artery occlusion; Branch retinal artery occlusion; CRAO; BRAO Images Retina References Sanborn GE, Magargal LE. Arterial obstructive disease ... A.M. Editorial team. Related MedlinePlus Health Topics ... audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among ...

  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. Volumetric-modulated arc therapy for left-sided breast cancer and all regional nodes improves target volumes coverage and reduces treatment time and doses to the heart and left coronary artery, compared with a field-in-field technique

    International Nuclear Information System (INIS)

    We compared two intensity-modulated radiotherapy techniques for left-sided breast treatment, involving lymph node irradiation including the internal mammary chain. Inverse planned arc-therapy (VMAT) was compared with a forward-planned multi-segment technique with a mono-isocenter (MONOISO). Ten files were planned per technique, delivering a 50-Gy dose to the breast and 46.95 Gy to nodes, within 25 fractions. Comparative endpoints were planning target volume (PTV) coverage, dose to surrounding structures, and treatment delivery time. PTV coverage, homogeneity and conformality were better for two arc VMAT plans; V95%PTV-T was 96% for VMAT vs 89.2% for MONOISO. Homogeneity index (HI)PTV-T was 0.1 and HIPTV-N was 0.1 for VMAT vs 0.6 and 0.5 for MONOISO. Treatment delivery time was reduced by a factor of two using VMAT relative to MONOISO (84 s vs 180 s). High doses to organs at risk were reduced (V30left lung = 14% using VMAT vs 24.4% with MONOISO; dose to 2% of the volume (D2%)heart = 26.1 Gy vs 32 Gy), especially to the left coronary artery (LCA) (D2%LCA = 34.4 Gy vs 40.3 Gy). However, VMAT delivered low doses to a larger volume, including contralateral organs (mean dose [Dmean]right lung = 4 Gy and Dmeanright breast = 3.2 Gy). These were better protected using MONOISO plans (Dmeanright lung = 0.8 Gy and Dmeanright breast = 0.4 Gy). VMAT improved PTV coverage and dose homogeneity, but clinical benefits remain unclear. Decreased dose exposure to the LCA may be clinically relevant. VMAT could be used for complex treatments that are difficult with conventional techniques. Patient age should be considered because of uncertainties concerning secondary malignancies. (author)

  9. 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

    International Nuclear Information System (INIS)

    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.)

  10. Finite Boltzmann schemes

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2006-01-01

    In the special case of relaxation parameter = 1 lattice Boltzmann schemes for (convection) diffusion and fluid flow are equivalent to finite difference/volume (FD) schemes, and are thus coined finite Boltzmann (FB) schemes. We show that the equivalence is inherent to the homology of the Maxwell-Bolt

  11. 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...

  12. 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; 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

  13. Vasorelaxing effects of estetrol in rat arteries.

    Science.gov (United States)

    Hilgers, Rob H P; Oparil, Suzanne; Wouters, Wout; Coelingh Bennink, Herjan J T

    2012-10-01

    This study compared ex vivo relaxing responses to the naturally occurring human hormone estetrol (E(4)) vs 17β-estradiol (E(2)) in eight different vascular beds. Arteries were mounted in a myograph, contracted with either phenylephrine or serotonin, and cumulative concentration-response curves (CRCs) to E(4) and E(2) (0·1-100  μmol/l) were constructed. In all arteries tested, E(4) had lower potency than E(2), although the differential effect was less in larger than smaller arteries. In uterine arteries, the nonselective estrogen receptor (ER) blocker ICI 182 780 (1  μmol/l) caused a significant rightward shift in the CRC to both E(4) and E(2), indicating that the relaxation responses were ER dependent. Pharmacological blockade of nitric oxide (NO) synthases by N(ω)-nitro-L-arginine methyl ester (L-NAME) blunted E(2)-mediated but not E(4)-mediated relaxing responses, while inhibition of prostaglandins and endothelium-dependent hyperpolarization did not alter relaxation to either E(4) or E(2) in uterine arteries. Combined blockade of NO release and action with L-NAME and the soluble guanylate cyclase (sGC) inhibitor ODQ resulted in greater inhibition of the relaxation response to E(4) compared with E(2) in uterine arteries. Endothelium denudation inhibited responses to both E(4) and E(2), while E(4) and E(2) concentration-dependently blocked smooth muscle cell Ca(2)(+) entry in K(+)-depolarized and Ca(2)(+)-depleted uterine arteries. In conclusion, E(4) relaxes precontracted rat arteries in an artery-specific fashion. In uterine arteries, E(4)-induced relaxations are partially mediated via an endothelium-dependent mechanism involving ERs, sGC, and inhibition of smooth muscle cell Ca(2)(+) entry, but not NO synthases or endothelium-dependent hyperpolarization. PMID:22798015

  14. A COMPARATIVE STUDY OF THE EFFICACY AND TOLERABILITY OF ORIGINAL AND GENERIC BISOPROLOL IN MONOTHERAPY OR IN COMBINATION WITH S-AMLODIPINE AND INDAPAMIDE IN PATIENTS WITH ARTERIAL HYPERTENSION 1-2 DEGREES. RESULTS OF THE CLINICAL RANDOMIZED CROSSOVER STUDY

    Directory of Open Access Journals (Sweden)

    S. Yu. Martsevich

    2011-01-01

    Full Text Available Aim. To study the clinical equivalence of original and generic drugs of bisoprolol in patients with arterial hypertension (HT 1-2 degrees according to protocol recommended by the Society of Cardiology of the Russian Federation for comparative studies. Material and methods. 30 patients with HT 1-2 degrees were examined. Patients were randomized into group 1 (original bisoprolol 5 mg/day or group 2 (generic bisoprolol 5 mg/day. In case of insufficient antihypertensive effect bisoprolol dose was increased or S-amlodipine and then indapamide were added. After the first treatment period (8 weeks was completed 2-week wash-out period started and then the second period (8 weeks of treatment (taking alternative medicine of bisoprolol began. Blood pressure (BP, heart rate, ECG, adverse effects were recorded in patients. Results. After 8 weeks of therapy BP reduction was 27.2±12.2/12.0±6.1 mm Hg in group 1 and 29.9±10.5/12.5±7.2 mm Hg in group 2 (p<0.001 for both groups, intergroup differences were insignificant. Target BP levels were achieved in 79.3% of patients in both groups. Heart rate decrease was 11.1±12.9 in group 1 and 8.5±8.6 beats/min in group 2 (p<0.05 for both groups. Significant dynamics of PQ interval were not found in both groups. The groups were comparable in terms of treatment safety and tolerability. Conclusion. Therapeutic equivalence of original and generic bisoprolol is shown in patients with HT 1-2 degrees.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. Angioplasty and stent placement - peripheral arteries - discharge

    Science.gov (United States)

    Percutaneous transluminal angioplasty - peripheral artery - discharge; PTA - peripheral artery - discharge; Angioplasty - peripheral artery - discharge; Balloon angioplasty - peripheral artery- discharge; PAD - PTA ...

  3. 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. PMID:27078495

  4. 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.

  5. Superselective intra-arterial infusion via the superficial temporal artery and occipital artery for gingival carcinoma of the mandible. Simultaneous catheter placement to the maxillary artery and facial artery

    International Nuclear Information System (INIS)

    Superselective intra-arterial infusion via the superficial temporal artery (STA) has become useful for oral cancer. Approaching via the occipital artery (OA) enables superselective intra-arterial infusion when catheter placement via the STA is impossible. Therefore, simultaneous catheter placement via the STA and OA is possible. We report a surgical method of simultaneous catheter placement via the STA and OA to achieve retrograde superselective intra-arterial infusion for gingival carcinoma of the mandible. Preoperatively, three-dimensional computed tomography angiography was performed to identify the route of the external carotid artery and branches such as the STA, OA, maxillary artery, and facial artery (FA). Thirteen patients with mandibular gingival cancer underwent catheter placement via the STA and OA under local anesthesia. Catheter placement via the STA and OA was superselectively successful in all the patients. The mean operating time was 150.8 min. Catheter placed to the FA via the OA was dislocated during the treatment in one patient, and so the catheter was replaced. This method is useful to enable superselective intra-arterial chemotherapy to the whole gingival carcinoma of the mandible from the start of treatment compared with approaching via the STA. (author)

  6. Rascal finite sets

    Directory of Open Access Journals (Sweden)

    Pier Luigi Papini

    2004-12-01

    Full Text Available In this paper we consider finite sets in a normed, infinite dimensional space. First, we study the following problem: given a finite set $F$, does there exist a sphere containing $F$ on its surface? We indicate some results and we collect some examples concerning this problem, also for sets of small cardinality. Then we give an example of a three-point set, in a Hilbert space, without incenter.

  7. 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

  8. 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.

  9. [Popliteal artery entrapment syndrome].

    Science.gov (United States)

    Musumeci, S; Iuppa, A; Beneventano, G; Rinella, P; Mammano, M; Cinquegrani, E

    1986-12-15

    Trapped popliteal artery syndrome is relatively uncommon: the literature reports some 60 cases. The clinical picture is linked to compression of the popliteal artery by the gastrocnemius as it contracts, thus distorting the arterial route. The result is an interruption in the blood flow distally to the area involved due to stenosis of the blood vessel that is at first functional but becomes organic. PMID:3808379

  10. 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.

  11. Fluid-structure interaction simulations of cerebral arteries modeled by isotropic and anisotropic constitutive laws

    Science.gov (United States)

    Tricerri, Paolo; Dedè, Luca; Deparis, Simone; Quarteroni, Alfio; Robertson, Anne M.; Sequeira, Adélia

    2015-03-01

    This paper considers numerical simulations of fluid-structure interaction (FSI) problems in hemodynamics for idealized geometries of healthy cerebral arteries modeled by both nonlinear isotropic and anisotropic material constitutive laws. In particular, it focuses on an anisotropic model initially proposed for cerebral arteries to characterize the activation of collagen fibers at finite strains. In the current work, this constitutive model is implemented for the first time in the context of an FSI formulation. In this framework, we investigate the influence of the material model on the numerical results and, in the case of the anisotropic laws, the importance of the collagen fibers on the overall mechanical behavior of the tissue. With this aim, we compare our numerical results by analyzing fluid dynamic indicators, vessel wall displacement, Von Mises stress, and deformations of the collagen fibers. Specifically, for an anisotropic model with collagen fiber recruitment at finite strains, we highlight the progressive activation and deactivation processes of the fibrous component of the tissue throughout the wall thickness during the cardiac cycle. The inclusion of collagen recruitment is found to have a substantial impact on the intramural stress, which will in turn impact the biological response of the intramural cells. Hence, the methodology presented here will be particularly useful for studies of mechanobiological processes in the healthy and diseased vascular wall.

  12. Heritability of cilioretinal arteries

    DEFF Research Database (Denmark)

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

    2005-01-01

    of healthy monozygotic and dizygotic twins were examined using digital fundus photography and visual assessment of grayscale fundus photographs and color transparencies to detect the presence of cilioretinal arteries. RESULTS: Cilioretinal arteries were present in 45.1% of participants and 28.8% of eyes....... The majority of cilioretinal arteries, 88.2%, were located temporally, and 11.8% were located nasally. Monozygotic twins had higher concordance rates for cilioretinal arteries than dizygotic twins. Tetrachoric correlations and Mantel-Haenszel odds ratios demonstrated statistically significant evidence...

  13. Peripheral artery disease - legs

    Science.gov (United States)

    ... if they have a history of: Abnormal cholesterol Diabetes Heart disease (coronary artery disease) High blood pressure ( hypertension ) Kidney disease involving hemodialysis Smoking Stroke ( cerebrovascular disease )

  14. Physical inactivity and arterial stiffness in COPD

    OpenAIRE

    Sievi NA; Franzen D; Kohler M.; Clarenbach CF

    2015-01-01

    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 ...

  15. Right Coronary Artery Arising from Circumflex Artery: A Case of Single Coronary Artery Anomaly

    Directory of Open Access Journals (Sweden)

    Hekim Karapınar

    2013-08-01

    Full Text Available Coronary artery anomalies could be cause of conflicts for catheterization, especially, in the setting of acute coronary syndrome. We described a case of rare single coronary anomaly which the right coronary artery arisen from terminal part of left circumflex artery. Patient was presented with non-ST segment elevation myocardial infarction. Coronary angiography revealed subtotal stenosis of left anterior descending artery at the mid portion. Left circumflex artery lying in usual route and branch out the posterior descending artery. The right coronary artery arisen from terminal circumflex artery. Left anterior descending artery lesion was stented without any complication.

  16. Comparison Study on the Performances of Finite Volume Method and Finite Difference Method

    OpenAIRE

    Bo Yu(Brookhaven National Lab); Dongjie Wang; Xinyu Zhang; Wang Li; Renwei Liu

    2013-01-01

    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 pe...

  17. 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

  18. 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.

  19. A Finite Element Framework for Some Mimetic Finite Difference Discretizations

    OpenAIRE

    Rodrigo, Carmen; Gaspar, Francisco; Hu, Xiaozhe; Zikatanov, Ludmil

    2015-01-01

    In this work we derive equivalence relations between mimetic finite difference schemes on simplicial grids and modified N\\'ed\\'elec-Raviart-Thomas finite element methods for model problems in $\\mathbf{H}(\\operatorname{\\mathbf{curl}})$ and $H(\\operatorname{div})$. This provides a simple and transparent way to analyze such mimetic finite difference discretizations using the well-known results from finite element theory. The finite element framework that we develop is also crucial for the design...

  20. Artery Agenesis: Ipsilateral Common Carotid Artery Hypoplasia

    Directory of Open Access Journals (Sweden)

    Omer Kaya

    2014-01-01

    Full Text Available A 42-year-old female patient, who had been diagnosed with an occlusion of her left internal carotid artery (ICA following Doppler ultrasonographic (US and digitally-subtracted angiographic (DSA examinations performed in an outer healthcare center in order to eliminate the underlying cause of her complaint of amorosis fugax, later applied to our hospital with the same complaint. At Doppler US performed in our hospital’s radiology department, her right common carotid artery (CCA was normal, but her left CCA was hypoplastic. The right internal artery (ICA was validated as normal. At the left side, however, the ICA was apparent only as a stump and it did not demonstrate a continuity. The diagnosis of ICA agenesis was confirmed by the utilization of Doppler US, CT, and DSA imaging, and it was concluded also that ipsilateral CCA hypoplasia could be evaluated as an important clue to the diagnosis of ICA agenesis.

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. Diagnosis of Intracranial Artery Dissection

    Science.gov (United States)

    KANOTO, Masafumi; HOSOYA, Takaaki

    2016-01-01

    Cerebral arterial dissection is defined as a hematoma in the wall of a cervical or an intracranial artery. Cerebral arterial dissection causes arterial stenosis, occlusion, and aneurysm, resulting in acute infarction and hemorrhage. Image analysis by such methods as conventional angiography, computed tomography, magnetic resonance imaging, and so on plays an important role in diagnosing cerebral arterial dissection. In this study, we explore the methods and findings involved in the diagnosis of cerebral arterial dissection. PMID:27180630

  6. 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.

  7. Finite Blaschke products: a survey

    OpenAIRE

    Garcia, Stephan Ramon; Mashreghi, Javad; Ross, William T.

    2015-01-01

    A finite Blaschke product is a product of finitely many automorphisms of the unit disk. This brief survey covers some of the main topics in the area, including characterizations of finite Blaschke products, approximation theorems, derivatives and residues of finite Blaschke products, geometric localization of zeros, and selected other topics.

  8. Difference in carotid artery elasticity in subjects with different brachial artery kinetic of vasodilatation.

    Science.gov (United States)

    Tripolino, C; Gnasso, A; Carallo, C; Scavelli, F B; Irace, C

    2016-08-01

    Increased carotid stiffness and impaired brachial artery flow-mediated dilatation (FMD) associate with cardiovascular events. We have previously reported three FMD patterns based on the time of maximal dilatation. The aim of the present study was to verify whether different FMD patterns associate with carotid artery stiffness. In all, 133 subjects were enrolled. All participants underwent complete clinical examination, blood sampling and ultrasound study. FMD was used as a measure of endothelial function. Based on the maximal brachial artery FMD, subjects were divided into Early dilators (peak FMD at 50 s), Late dilators (peak FMD over 50 s) and No dilators. Echo-Doppler evaluation of carotid arteries was performed in order to calculate elastic indexes (strain, β-stiffness index and distensibility). In all, 64 subjects were classified as Early FMD, 36 as Late FMD and 33 as No dilators. Age, gender and cardiovascular risk factors were comparable among three groups. Early FMD had higher values of strain compared with both Late and no Dilators (PFMD and No Dilators were detected. Our results demonstrate that common carotid artery elasticity indexes significantly differ among Early, Late and No dilators. Subjects with delayed or absent brachial artery dilatation have stiffer common carotid arteries compared with subjects with early dilatation. In conclusion, our research suggests that the assessment of the kinetics of FMD in a clinical setting might represent a useful screening tool to improve the cardiovascular risk stratification. PMID:26467820

  9. Proximity of arteries to the anterior ulna with changing flexion.

    Science.gov (United States)

    Enad, Jerome G; Douglas, Thomas J; Ruland, Robert T

    2015-04-01

    During surgery for elbow fracture, wires and screws crossing the elbow from posterior to anterior place the brachial and ulnar arteries at risk for inadvertent penetration. The authors' goal was to define the sagittal proximity of the brachial and ulnar arteries to the proximal ulna throughout an arc of elbow motion using dynamic fluoroscopy. The brachial artery was injected with barium in 10 fresh-frozen cadaveric elbows. Sagittal fluoroscopic images were obtained at elbow flexion angles of 0°, 30°, 60°, 90°, and 120°. Two measurements were obtained at each flexion angle: (1) the distance between the coronoid tip and the brachial artery and (2) the distance between the coronoid base and the ulnar artery. One-way analysis of variance was used to compare mean distances for each flexion angle within each measurement group. A coronal image identified the mediolateral course of the brachial artery. The distance from the coronoid tip to the brachial artery significantly increased with increasing flexion from 0° to 60° (P120° (P<.002). The brachial artery traversed lateral to the coronoid in 9 of 10 specimens. The brachial and ulnar arteries are located further from the coronoid with increasing elbow flexion to at least 60°, and the brachial artery is typically located lateral to the coronoid in the coronal plane. These measurements can be used as surgical guides to reduce the risk of arterial injury during olecranon fracture surgery. PMID:25901616

  10. Splanchnic artery aneurysms

    Directory of Open Access Journals (Sweden)

    Davidović Lazar B.

    2006-01-01

    Full Text Available Introduction. Splanchnic artery aneurysms are uncommon but important vascular entity because nearly 25% of all cases present as surgical emergency. Objective. The purpose of our study was to present nine patients operated on at the Institute of cardiovascular diseases, as well as literature review of clinical presentation of the disease. Method. There were three splenic artery aneurysms, two celiac trunk aneurysms, and one aneurysm of the hepatic, superior mesenteric, inferior mesenteric and gastroduodenal artery. All patients were males, mean aged 67.5 years (60-73. In four patients, splanchnic artery aneurysm was discovered accidentally during routine ultrasonographic and angiographic examinations of the abdominal aorta. At that time, arteriovenous fistula was diagnosed in a patient No 1; it was formed after rupture of the splenic artery aneurysm into the splenic vein. Three aneurysms were manifested by abdominal pain and palpable pulsating abdominal mass. Two patients were admitted as urgent cases in the state of hemorrhagic shock and signs of intraabdominal bleeding due to rupture of the splenic and hepatic arteries. In 7 cases, diagnosis was made preoperatively by means of ultrasonography and angiography; in two patients, accurate diagnosis was confirmed during surgery. Results. Proximal and distal ligation of the artery was performed in a patient with rupture of the splenic aneurysm into the splenic vein that caused arteriovenous fistula. Gastroduodenal artery aneurysm was treated by trans-aneurysmatic ligation of its "entering" and "exiting" branches. Aneurysms of distal part of the superior mesenteric and splenic artery were resected without further reconstruction. Partial resection of the aneurysm and endoaneurysmorrhaphy was carried out in one case of celiac trunk aneurysm, and in another, after aneurysm resection, the restoration of blood flow through the hepatic and lienal artery was achieved by Dacron grafts. In a patient with the

  11. 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.

  12. 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. PMID:21336554

  13. 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.

  14. [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.

  15. Role of non-contrast balanced steady-state free precession megnetic resonance angiography compared to contrast-enhanced megnetic resonance angiography in diagnosing renal artery stenosis: a meta-analysis

    Institute of Scientific and Technical Information of China (English)

    Tao Weijing; Shen Yang; Guo Lili; Bo Genji

    2014-01-01

    Background Balanced steady-state free precession MR angiography (b-SSFP MRA) has shown great promise in diagnosing renal artery stenosis (RAS) as a non-contrast MR angiography (NC-MRA) method.However,results from related studies are inconsistent.The purpose of this meta-analysis was to assess the accuracy of b-SSFP MRA compared to contrast-enhanced MR angiography (CE-MRA) in diagnosing RAS.Methods English and Chinese studies that were published prior to September 4,2013 and that assessed b-SSFP MRA diagnostic performance in RAS patients were reviewed.Quality of the literature was assessed independently by two observers.The statistical analysis was adopted by the software of Meta-Disc version 1.4.Using the heterogeneity test,a statistical effect model was chosen to calculate different pooled weighted values.The receiver operator characteristic (ROC) space and Spearman correlation coefficient were to explore threshold effect.Sensitivity analysis and the publication bias were performed to demonstrate if the pooled estimates were stable and reliable.We produced forest plots to calculate the pooled values and corresponding 95% confidence interval (C/) of sensitivity,specificity,positive likelihood ratio (PLR),negative likelihood ratio (NLR),diagnostic odds ratio (DOR),and constructed a summary receiver operating characteristic curve (SROC) to calculate the area under the curve (AUC).Results A total of 10 high quality articles were used in this meta-analysis.The studies showed a high degree of heterogeneity.The "shoulder-arm" shape in the ROC plot and the Spearman correlation coefficient between the log(SEN) and log(1-SPE) suggested that there was a threshold effect.Sensitivity analysis demonstrated that the actual combined effect size was equal to the theoretical combined effect size.The publication bias was low after quality evaluation of the literature and the construction of a funnel plot.The pooled sensitivity was 0.88 (95% CI,0.83-0.91) and pooled specificity

  16. Determination of the threshold of cardiac troponin I associated with an adverse postoperative outcome after cardiac surgery: a comparative study between coronary artery bypass graft, valve surgery, and combined cardiac surgery

    Science.gov (United States)

    Fellahi, Jean-Luc; Hedoire, François; Le Manach, Yannick; Monier, Emmanuel; Guillou, Louis; Riou, Bruno

    2007-01-01

    Introduction The objective of the present study was to compare postoperative cardiac troponin I (cTnI) release and the thresholds of cTnI that predict adverse outcome after elective coronary artery bypass graft (CABG), after valve surgery, and after combined cardiac surgery. Methods Six hundred and seventy-five adult patients undergoing conventional cardiac surgery with cardiopulmonary bypass were retrospectively analyzed. Patients in the CABG (n = 225) and valve surgery groups (n = 225) were selected after matching (age, sex) with those in the combined surgery group (n = 225). cTnI was measured preoperatively and 24 hours after the end of surgery. The main endpoint was a severe postoperative cardiac event (sustained ventricular arrhythmias requiring treatment, need for inotropic support or intraaortic balloon pump for at least 24 hours, postoperative myocardial infarction) and/or death. Data are presented as the median and the odds ratio (95% confidence interval). Results Postoperative cTnI levels were significantly different among the three groups (combined surgery, 11.0 (9.5–13.1) ng/ml versus CABG, 5.2 (4.7–5.7) ng/ml and valve surgery, 7.8 (7.6–8.0) ng/ml; P < 0.05). The thresholds of cTnI predicting severe cardiac event and/or death were also significantly different among the three groups (combined surgery, 11.8 (11.5–14.8) ng/ml versus CABG, 7.8 (6.7–8.8) ng/ml and valve surgery, 9.3 (8.0–14.0) ng/ml; P < 0.05). An elevated cTnI above the threshold in each group was significantly associated with a severe cardiac event and/or death (odds ratio, 4.33 (2.82–6.64)). Conclusion The magnitude of postoperative cTnI release is related to the type of cardiac surgical procedure. Different thresholds of cTnI must be considered according to the procedure type to predict early an adverse postoperative outcome. PMID:17888156

  17. 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.

  18. 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.

  19. Finite temperature field theory

    CERN Document Server

    Das, Ashok

    1997-01-01

    This book discusses all three formalisms used in the study of finite temperature field theory, namely the imaginary time formalism, the closed time formalism and thermofield dynamics. Applications of the formalisms are worked out in detail. Gauge field theories and symmetry restoration at finite temperature are among the practical examples discussed in depth. The question of gauge dependence of the effective potential and the Nielsen identities are explained. The nonrestoration of some symmetries at high temperature (such as supersymmetry) and theories on nonsimply connected space-times are al

  20. 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.

  1. 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

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

    Science.gov (United States)

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

    2016-01-01

    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. PMID:27491333

  3. 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.

  4. 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.

  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. PMID:25897758

  7. Impaired arterial reactivity following cytomegalovirus infection in the immunosuppressed rat.

    OpenAIRE

    Eerdmans, P. H.; Persoons, M. C.; Debets, S. J.; Struijker Boudier, H. A.; Smits, J. F.; Bruggeman, C. A.; De Mey, J. G.

    1996-01-01

    1. Cytomegalovirus (CMV) is a major pathogen in immunocompromised individuals and may participate in the pathogenesis of atherosclerosis in the general population. We evaluated whether CMV-infection alters the function of arterial smooth muscle. 2. Blood pressure (BP) and arterial reactivity were recorded in immunosuppressed rats that had been infected with CMV (10(5) plaque forming units i.p.). Furthermore, the reactivity of isolated arteries was compared between CMV-infected rats and rats i...

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Finite fields and cryptology

    Directory of Open Access Journals (Sweden)

    Ennio Cortellini

    2003-10-01

    Full Text Available The problem of a computationally feasible method of finding the discrete logarithm in a (large finite field is discussed, presenting the main algorithms in this direction. Some cryptographic schemes based on the discrete logarithm are presented. Finally, the theory of linear recurring sequences is outlined, in relation to its applications in cryptology.

  13. Finite fields and cryptology

    OpenAIRE

    Ennio Cortellini

    2003-01-01

    The problem of a computationally feasible method of finding the discrete logarithm in a (large) finite field is discussed, presenting the main algorithms in this direction. Some cryptographic schemes based on the discrete logarithm are presented. Finally, the theory of linear recurring sequences is outlined, in relation to its applications in cryptology.

  14. Finite-dimensional utilities

    OpenAIRE

    Yutaka Nakamura

    2000-01-01

    Sufficient axioms are identified for the existence of a finite- dimensional quasilinear utility function whose lexicographically ordered vectors preserve a decision maker's preference order on a mixture set ${\\cal M}$. It is shown that those axioms are also necessary for the linear lexicographic representation when the underlying set ${\\cal M}$ is a mixture space.

  15. Tibolone and its metabolites acutely relax rabbit coronary arteries in vitro

    DEFF Research Database (Denmark)

    Lund, Claus Otto; Nilas, Lisbeth; Pedersen, Susan Helene;

    2004-01-01

    OBJECTIVES: To compare the acute effects of estradiol, tibolone and its metabolites on coronary arteries in vitro and to investigate possible vascular mechanisms. METHODS: Coronary artery ring segments from female rabbits were mounted in myographs for isometric tension recordings. Concentration...

  16. 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.

  17. 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。

  18. Nonlinear, finite deformation, finite element analysis

    Science.gov (United States)

    Nguyen, Nhung; Waas, Anthony M.

    2016-06-01

    The roles of the consistent Jacobian matrix and the material tangent moduli, which are used in nonlinear incremental finite deformation mechanics problems solved using the finite element method, are emphasized in this paper, and demonstrated using the commercial software ABAQUS standard. In doing so, the necessity for correctly employing user material subroutines to solve nonlinear problems involving large deformation and/or large rotation is clarified. Starting with the rate form of the principle of virtual work, the derivations of the material tangent moduli, the consistent Jacobian matrix, the stress/strain measures, and the objective stress rates are discussed and clarified. The difference between the consistent Jacobian matrix (which, in the ABAQUS UMAT user material subroutine is referred to as DDSDDE) and the material tangent moduli ( C e ) needed for the stress update is pointed out and emphasized in this paper. While the former is derived based on the Jaumann rate of the Kirchhoff stress, the latter is derived using the Jaumann rate of the Cauchy stress. Understanding the difference between these two objective stress rates is crucial for correctly implementing a constitutive model, especially a rate form constitutive relation, and for ensuring fast convergence. Specifically, the implementation requires the stresses to be updated correctly. For this, the strains must be computed directly from the deformation gradient and corresponding strain measure (for a total form model). Alternatively, the material tangent moduli derived from the corresponding Jaumann rate of the Cauchy stress of the constitutive relation (for a rate form model) should be used. Given that this requirement is satisfied, the consistent Jacobian matrix only influences the rate of convergence. Its derivation should be based on the Jaumann rate of the Kirchhoff stress to ensure fast convergence; however, the use of a different objective stress rate may also be possible. The error associated

  19. One-pion exchange potential at finite temperature and finite density

    International Nuclear Information System (INIS)

    By means of the real-time temperature Green function method, we extend the one-pion exchange potential (OPEP) with pseudovector coupling and pseudoscalar coupling to finite density and finite temperature. After summing all the bubble diagrams of the exchange of the pion, we find that the density effects on the effective mass of pion and OPEP are considerable at low temperature. The density effects and the temperature effects of OPEP are compared. (author)

  20. Elastomeric PGS scaffolds in arterial tissue engineering.

    Science.gov (United States)

    Lee, Kee-Won; Wang, Yadong

    2011-01-01

    Cardiovascular disease is one of the leading cause of mortality in the US and especially, coronary artery disease increases with an aging population and increasing obesity. Currently, bypass surgery using autologous vessels, allografts, and synthetic grafts are known as a commonly used for arterial substitutes. However, these grafts have limited applications when an inner diameter of arteries is less than 6 mm due to low availability, thrombotic complications, compliance mismatch, and late intimal hyperplasia. To overcome these limitations, tissue engineering has been successfully applied as a promising alternative to develop small-diameter arterial constructs that are nonthrombogenic, robust, and compliant. Several previous studies have developed small-diameter arterial constructs with tri-lamellar structure, excellent mechanical properties and burst pressure comparable to native arteries. While high tensile strength and burst pressure by increasing collagen production from a rigid material or cell sheet scaffold, these constructs still had low elastin production and compliance, which is a major problem to cause graft failure after implantation. Considering these issues, we hypothesized that an elastometric biomaterial combined with mechanical conditioning would provide elasticity and conduct mechanical signals more efficiently to vascular cells, which increase extracellular matrix production and support cellular orientation. The objective of this report is to introduce a fabrication technique of porous tubular scaffolds and a dynamic mechanical conditioning for applying them to arterial tissue engineering. We used a biodegradable elastomer, poly (glycerol sebacate) (PGS) for fabricating porous tubular scaffolds from the salt fusion method. Adult primary baboon smooth muscle cells (SMCs) were seeded on the lumen of scaffolds, which cultured in our designed pulsatile flow bioreactor for 3 weeks. PGS scaffolds had consistent thickness and randomly distributed macro

  1. Coronary artery spasm

    Science.gov (United States)

    ... blocker or a long-acting nitrate long-term. Beta-blockers are another type of medicine that is used with other coronary artery problems. However, beta-blockers may make this problem worse. They should be ...

  2. Peripheral Arterial Disease

    Science.gov (United States)

    Peripheral arterial disease (PAD) happens when there is a narrowing of the blood vessels outside of your heart. The cause of ... smoking. Other risk factors include older age and diseases like diabetes, high blood cholesterol, high blood pressure, ...

  3. 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 ...

  4. 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 ...

  5. Coronary Artery Bypass Surgery

    Science.gov (United States)

    ... don't help, you may need coronary artery bypass surgery. The surgery creates a new path for ... narrowed area or blockage. This allows blood to bypass (get around) the blockage. Sometimes people need more ...

  6. 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.

  7. FINITE DIFFERENCE MODEL OF A CIRCULAR FIN WITH RECTANGULAR PROFILE

    OpenAIRE

    GİRGİN, İbrahim; EZGİ, Cüneyt

    2015-01-01

    Numerical methods are commonly used in engineering where the analytical resultsare not reached or as a support of experimental studies. Various techniques are being usedas a numeritical method as finite difference, finite volume or finite elements, etc. In thisstudy, numerical solutions are obtained for a circular fin of rectangular profile using finitedifference method, and the results are compared to the analytical solutions. It is seen thatthe analytical solution and numerical results are ...

  8. 症状性颅、颈部动脉狭窄在3.0T上的MRA与DSA比较研究%Evaluation of 3.0 Tesla MRA in diagnosing symptomatic craniocervicai artery stenosis: a comparative study with DSA

    Institute of Scientific and Technical Information of China (English)

    李梅; 李明华; 王建波; 王珏; 方淳; 乔瑞华

    2009-01-01

    目的 前瞻性分析3.0T应用SENSE技术的高分辨率对比增强容积扫描MRA(CEMRA)和3DTOFMRA在临床疑有颅、颈部动脉狭窄性病变患者中的应用价值.方法 46例临床怀疑颅、颈部动脉狭窄的患者接受头颅MRI平扫、头颅3DTOFMRA和颈部CEMRA检查.动脉狭窄的程度与DSA检查结果进行相关性比较.结果 MRA显示各段颅、颈部动脉狭窄的不同程度和DSA检查显著相关(Rs=0.97,P<0.01).以DSA结果为金标准,狭窄程度超过50%者MRA诊断灵敏度为100%,特异度为99.4%、准确率为99.4%.结论 3.0T的3DTOFMRA和高分辨率CEMRA检查能可靠和有效地评价颅、颈部动脉狭窄性病变,可作为DSA术前必要的检查技术,或可替代传统DSA诊断性检查.%Objective To prospectively evaluate 3D time-of-flight magnetic resonance angiography (3DTOF MRA) and high resolution contrast enhanced volume scan magnetic resonance angiography (CEMRA) with sensitivity encoding in diagnosing craniocervical artery stenosis. Methods Forty-six patients suspected with craniocervical artery diseases underwent MRI, 3DTOF MRA of the head and also CEMRA of the neck. The images of MRA were reconstructed with MIP and VR. The degree of arterial stenosis demonstrated on MRA was compared with that showed on digital subtraction angiography(DSA), and the data were analyzed with Spearman rank correlation coefficient (Rs). Results Excellent correlation in determining the degree of craniocervical artery stenosis existed between MRA and DSA (Rs = 0.97). With DSA as a golden standard, the sensitivity, specificity and accuracy of MRA in detecting over 50% arterial stenosis were 100%, 99.4% and 99.4% respectively. Conclusion 3DTOF MRA and CEMRA with sensitivity encoding at 3.0T are reliable and effective examinations for evaluating craniocervical artery disease. These techniques can be used as the necessary exams before DSA and can even substitute for the conventional DSA in some instances.

  9. 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.

  10. 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.

  11. 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.

  12. Hadronic property at finite density

    OpenAIRE

    Takaishi, Tetsuya

    2004-01-01

    We report on three topics on finite density simulations: (i) the derivative method for hadronic quantities, (ii) phase fluctuations in the vicinity of the critical temperature and (iii) the density of states method at finite isospin density.

  13. Supersymmetry at finite temperature

    International Nuclear Information System (INIS)

    The consequences of the incorporation of finite temperature effects in fields theories are investigated. Particularly, we consider the sypersymmetric non-linear sigma model, calculating the effective potencial in the large N limit. Initially, we present the 1/N expantion formalism and, for the O(N) model of scalar field, we show the impossibility of spontaneous symmetry breaking. Next, we study the same model at finite temperature and in the presence of conserved charges (the O(N) symmetry's generator). We conclude that these conserved charges explicitly break the symmetry. We introduce a calculation method for the thermodynamic potential of the theory in the presence of chemical potentials. We present an introduction to Supersymmetry in the aim of describing some important concepts for the treatment at T>0. We show that Suppersymmetry is broken for any T>0, in opposition to what one expects, by the solution of the Hierachy Problem. (author)

  14. Finite Sets and Counting

    OpenAIRE

    Preston, Chris

    2008-01-01

    We start by presenting a theory of finite sets using the approach which is essentially that taken by Whitehead and Russell in Principia Mathematica}, and which does not involve the natural numbers (or any other infinite set). This theory is then applied to prove results about structures which, like the natural numbers, satisfy the principle of mathematical induction, but do not necessarily satisfy the remaining Peano axioms.

  15. Infrared finite electron propagator

    International Nuclear Information System (INIS)

    We investigate the properties of a dressed electron which reduces, in a particular class of gauges, to the usual fermion. A one-loop calculation of the propagator is presented. We show explicitly that an infrared finite, multiplicative, mass shell renormalization is possible for this dressed electron, or, equivalently, for the usual fermion in the above-mentioned gauges. The results are in complete accord with previous conjectures. copyright 1997 The American Physical Society

  16. 晚期直肠癌动脉化疗灌注术与全身化疗对比分析%Comparative analysis of efficacy between arterial infusion chemotherapy and systemic chemotherapy in advanced rectal cancer

    Institute of Scientific and Technical Information of China (English)

    杨光华

    2011-01-01

    目的 对直肠癌动脉化疗灌注疗效进行分析.方法 将14例Dukes'D期直肠癌行动脉灌注化疗的设为观察组,将同时期24例晚期直肠癌行单纯化疗的设为对照组进行对比研究.结果 观察组总有效率为100%(14/14),对照组总有效率为70.83%(17/24),有统计学意义(P<0.05).结论 Dukes'D期直肠癌患者动脉化疗灌注术及栓塞术比单纯化疗短期疗效明显提高.%Objective To analyze the efficacy of arterial infusion chemotherapy in advanced rectal cancer. Methods Totally 14 patients in Dukes' D period rectal cancer were selected for experimental group and 24 patients with advanced rectal cancer in the same period were selected for control group.The experimental group was treated by arterial infusion chemotherapy and the control group was treated with systemic chemotherapy. Results The total effective rate of the experimental group and the control group were respectively 14/14 (100%), 17/24 (70.83%). The differences between the two groups had statistically significant ( P < 0.05 ). Conclusions The efficacy of arterial infusion chemotherapy was obviously superior to systemic chemotherapy in patients with Dukes' D period rectal cancer.

  17. On Finite Alphabet Compressive Sensing

    OpenAIRE

    Das, Abhik Kumar; Vishwanath, Sriram

    2013-01-01

    This paper considers the problem of compressive sensing over a finite alphabet, where the finite alphabet may be inherent to the nature of the data or a result of quantization. There are multiple examples of finite alphabet based static as well as time-series data with inherent sparse structure; and quantizing real values is an essential step while handling real data in practice. We show that there are significant benefits to analyzing the problem while incorporating its finite alphabet natur...

  18. 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.

  19. Arterial stiffness, hypertension, and rational use of nebivolol

    Directory of Open Access Journals (Sweden)

    Enrico Agabiti-Rosei

    2009-05-01

    Full Text Available Enrico Agabiti-Rosei, Enzo Porteri, Damiano RizzoniClinica Medica, Department of Medical and Surgical Sciences, University of Brescia, ItalyAbstract: Arterial stiffness plays a key role in the pathophysiology of the cardiovascular system. Some indices of arterial stiffness (pulse wave velocity, augmentation index, characteristics of central blood pressure waveform may be presently calculated and evaluated in the clinical setting. Age and blood pressure are the two major clinical determinants of increased arterial stiffness, while molecular determinants of arterial stiffness are related to fibrotic components of the extracellular matrix, mainly elastin, collagen and fibronectin. Increased arterial stiffness has been consistently observed in conditions such as hypertension, dyslipidemia and diabetes. Arterial stiffness evaluated by means of carotid-femoral pulse wave velocity yielded prognostic significance beyond and above traditional risk factors. A more favorable effect of calcium channel blockers, diuretics and ACE inhibitors compared with β-blockers on indices of arterial stiffness was observed in several studies. It is conceivable that newer β-blockers with additional vasodilating properties, such as nebivolol, which has favorable effects on carbohydrate and lipid metabolism, as well as on endothelial function and on oxidative stress, may have favorable effects on arterial stiffness, compared with atenolol. In fact, in recent studies, nebivolol was demonstrated to improve artery stiffness to a greater extent than older β-blockers. Because endothelial dysfunction and increased arterial stiffness play an important role in the early atherosclerotic processes and are associated with poor outcomes and increased mortality, independently of blood pressure, the ability of nebivolol to enhance release of endothelium-derived nitric oxide, and consequently improve endothelial function and arterial stiffness, may have significant clinical

  20. Finite extensions of Bessel sequences

    OpenAIRE

    Bakić, Damir; Berić, Tomislav

    2015-01-01

    The paper studies finite extensions of Bessel sequences in infinite-dimensional Hilbert spaces. We provide a characterization of Bessel sequences that can be extended to frames by adding finitely many vectors. We also characterize frames that can be converted to Parseval frames by finite-dimensional perturbations. Finally, some results on excesses of frames and near-Riesz bases are derived.

  1. 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.

  2. Can one classify finite Postnikov pieces?

    CERN Document Server

    Moller, Jesper M

    2009-01-01

    We compare the classical approach of constructing finite Postnikov systems by k-invariants and the global approach of Dwyer, Kan, and Smith. We concentrate on the case of 3-stage Postnikov pieces and provide examples where a classification is feasible. In general though the computational difficulty of the global approach is equivalent to that of the classical one.

  3. Finite Element Analysis to Compare Stress Distribution of Four Different Framework Designs Zirconia Based Fixed Partial Denture%四种不同底层冠设计固定桥应力分布的有限元分析

    Institute of Scientific and Technical Information of China (English)

    郑志强; 林捷; 李厚轩; 陈群; 卢兆杰

    2013-01-01

    目的:使用三维有限元模型分析4种不同底层冠设计的3单位固定桥中界面应力分布情况。方法建立三维上颌第二前磨牙缺失3单位固定桥有限元模型,并进行4种不同底层冠设计。在桥体上施加600 N的垂直方向静荷载,以模拟最大咬合力。使用有限元分析不同设计的应力分布。结果Ⅰ型设计的最大拉应力在牙合面和龈端的饰瓷和底层冠交界处集中。Ⅱ型设计的最大拉应力在牙合面的饰瓷和底层冠交界处集中,龈端应力集中于桥体底部。Ⅲ型设计和Ⅳ型设计的拉应力分散于桥体底部。结论随着饰瓷包被面积减少,最大拉应力趋于从饰瓷和底层冠交界处向桥体和连接体底部分散。%Objective To use 3-dimensional finite element modeling to simulate stresses at the in-terface of 3-unit posterior fixed partial dentures (FPDs) made with 4 different framework designs . Meth-ods A 3-unit FPD was digitized and used to create 3-dimensional models of 4 framework preparation con-figurations . A load of 600 N was applied at the central point of the pontic’s occlusion surface . The stress values of 4 framework designs were calculated by finite element analysis . Results Tensile stress of Type Ⅰ design was maximal at the occlusal and gingival veneer-core interfaces . Tensile stress of TypeⅡ design was maximal at the occlusal veneer-core interface . Tensile stresses of Type Ⅲ and Type Ⅳ de-sign extended in the bottom of pontic . Conclusion In general ,the maximal tensile stresses of veneer-core interface extend in the bottom of pontic and connecters as the veneer area was decreased .

  4. Superselective pseudo-continuous arterial spin labeling angiography

    Energy Technology Data Exchange (ETDEWEB)

    Jensen-Kondering, Ulf [Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel (Germany); Lindner, Thomas, E-mail: thomas.lindner@uksh.de [Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel (Germany); Osch, Matthias J.P. van [C. J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden (Netherlands); Rohr, Axel; Jansen, Olav [Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel (Germany); Helle, Michael [Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel (Germany); Now with Philips GmbH Innovative Technologies, Research Laboratories, Hamburg (Germany)

    2015-09-15

    Highlights: • Superselective arterial spin labeling was capable of acquiring angiograms of individually selected arteries. • Image quality was similar compared with a routinely used time-of-flight angiography. • Superselective arterial spin labeling was utilized in patients with arterio-venous malformations and made it possible to visualize individual feeding vessels in a complete non-invasive way - Abstract: Purpose: To evaluate the utility of a novel non-contrast enhanced, vessel-selective magnetic resonance angiography (MRA) approach based on superselective pseudo-continuous arterial spin labeling (ASL) for the morphologic assessment of intracranial arteries when compared to a clinically used time-of-flight (TOF) MRA. Materials and methods: Three sets of selective ASL angiographies (right and left internal carotid artery, basilar artery) as well as one TOF data set were obtained from each of the five volunteers included in this study on a clinical 1.5T system. The depiction of arterial segments as well as their delineation was evaluated and independently analyzed by two radiologists. Additionally, the ASL angiography approach was performed in two patients suffering from arterio-venous malformations (AVM) in order to illustrate potential applications in a clinical setting. Results: In both angiography techniques, intracranial arteries and their segments (distal branches up to A5 segments of the anterior cerebral arteries, M8 segments of the middle cerebral arteries, and P5 segments of the posterior cerebral arteries) were continuously depicted with excellent inter-reader agreement (κ > 0.81). In AVM patients, reconstructed images of the TOF angiography presented similar information about the size and shape of the AVM as did superselective ASL angiography. In addition, the acquired ASL angiograms of selected vessels allowed assessing the blood supply of individually labeled arteries to the AVM which could also be confirmed by digital subtraction angiography

  5. Hepatocellular carcinoma with extensive hepatic artery injury: transcatheter arterial chemoembolization through collaterals after coil embolizatoin of gastric arteries

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gab Choul; Yoon, Hyun Ki; Hwang, Jae Cheol; Lee, Duck Hee; Song, Ho Young; Suh, Dong Jin; Lee, Yung Sang; Chung, Young Hwa; Sung, Gyu Bo [Ulsan Univ. College of Medicine, Seoul (Korea, Republic of); Ko, Ki Young [Catholic Univ. College of Medicine, Seoul (Korea, Republic of)

    1999-09-01

    To evaluate the efficacy and safety of transcatheter arterial chemoembolization(TACE) after coil embolization of the gastroduodenal artery in hepatocellular carcinoma cases with multiple collateral arteries caused by proper hepatic artery injury. Between March 1997 and November 1998, a prospective trial of transcatheter arterial chemoembolization (TACE) was performed through collaterals from the gastroduodenal artery of 31 hepatocellular carcinoma patients with extensive proper hepatic artery injury due to repeated TACE. Among this number, 16 (group A) underwent TACE after coil embolization of the right gastric and gastroduodenal artery. The other 15 patients (group B) underwent TACE without coil embolization. The two groups had the same TNM stage and Clild-Pugh status. During the follow-up period, group A underwent additional TACE 3.3 times, and group B 2.8 times. The therapeutic effect of TACE was evaluated with computed tomography and by measuring alpha-fetoprotein levels. Complications were evaluated by means of gastrofibroscopy, laboratory data, and evaluation of the patients' clinical symptoms. The results obtained after six months and one year were compared within and between each group. At six months follow-up, CT findings had improved or were unchanged in 11 patients(69 %) in group A, and four patients(27 %) in group B(p = 0.032). In ten patients in each group, the level of alpha-fetoprotein was above 200 ng/ml. Its level was decreased in five patients(50 %) and three patients(30 %), respectively. The six-month survival rate was 81 % (13/16) in group A and 67% (10/15) in group B (p 0.43), while the one-year survival figures for these two groups were 50 % (8/16) and 20 % (3/15), respectively(p = 0.135). In group A, the CT findings were steady in five out of eight patients(63 %), while in groupB, CT findings showed that tumors with increased alpha-fetoprotein levels had increased in size and/or number. In group A, it was found that in two (33 %) of six

  6. 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.

  7. 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.

  8. Applications of an exponential finite difference technique

    Science.gov (United States)

    Handschuh, Robert F.; Keith, Theo G., Jr.

    1988-01-01

    An exponential finite difference scheme first presented by Bhattacharya for one dimensional unsteady heat conduction problems in Cartesian coordinates was extended. The finite difference algorithm developed was used to solve the unsteady diffusion equation in one dimensional cylindrical coordinates and was applied to two and three dimensional conduction problems in Cartesian coordinates. Heat conduction involving variable thermal conductivity was also investigated. The method was used to solve nonlinear partial differential equations in one and two dimensional Cartesian coordinates. Predicted results are compared to exact solutions where available or to results obtained by other numerical methods.

  9. 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.

  10. 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...

  11. Calculation of narrowband lowpass filters with finite impulse response

    OpenAIRE

    Lanne, A. A.; Merkucheva, T. V.; Solonina, A. I.

    2009-01-01

    This study provides a review of digital filters known under the name “interpolated finite impulse response filters” (IFIR filters) that make it possible to create narrowband lowpass filters (LPF) with substantially reduced computational load and, consequently, a simpler design as compared with the conventional finite impulse response filters (FIR filters).

  12. Solution-adaptive finite element method in computational fracture mechanics

    Science.gov (United States)

    Min, J. B.; Bass, J. M.; Spradley, L. W.

    1993-01-01

    Some recent results obtained using solution-adaptive finite element method in linear elastic two-dimensional fracture mechanics problems are presented. The focus is on the basic issue of adaptive finite element method for validating the applications of new methodology to fracture mechanics problems by computing demonstration problems and comparing the stress intensity factors to analytical results.

  13. Object scrambling and finiteness in Turkish agrammatic production

    NARCIS (Netherlands)

    Duman, Tuba Yarbay; Aygen, Gulsat; Ozgirgin, Nese; Bastiaanse, Roelien; Özgirgin, N.

    2007-01-01

    This study investigates word order and finiteness in Turkish agrammatic aphasia. We compared the production of simple active sentences in base order (SOV) with active sentences in which the object moves over the subject, i.e., object scrambling (OSV). We elicited the same finite verbs for both sente

  14. 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.

  15. EFFECT OF MAGNETIC FIELD ON BLOOD FLOW THROUGH AN ARTERY: A NUMERICAL MODEL

    OpenAIRE

    J Misra; Shit, G.

    2007-01-01

    In this paper we have investigated the unsteady flow of blood by treating it as an incompressible, Newtonian, electrically conducting fluid in a straight segment of an elastic artery subject to a uniform transverse magnetic field. The problem is solved numerically with the theoretical assumption of 'local flow' model [?]. A sinusoidal variation of the arterial wall motion and a pulsatile pressure gradient have been studied. An implicit finite difference technique is used to analyze the flow. ...

  16. Translation operator for finite dmensional electromagnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Howard, A.Q. Jr.

    1981-04-01

    Computation of electromagnetic fields in particular applications is usually accompanied by the adhoc assumption that the field contains a finite number of degrees of freedom. Herein, this assumption is made at the outset. It is shown that if an annular region between two closed surfaces contains no sources or sinks and is isotropic, lossless and homogeneous, a unique translation operator can be defined algebraically. Conservation of energy defines the translation operator T to within an arbitrary unitary transformation. The conditions of causality, unitarity and energy conservation are shown to uniquely determine T. Both scalar and vector fields are treated. In both of these cases, frequency and time domain transforms are computed. The transform T is compared with the analagous one as derived from the time domain Stratton-Chu Formulation. The application to a radiation condition boundary constraint on finite difference and finite element computations is discussed.

  17. [Splenic artery aneurysms].

    Science.gov (United States)

    Colović, R; Davidović, L; Bilanović, D; Krivokapić, Z; Grubor, N; Cvetković, S; Radak, V; Marković, M

    2006-01-01

    Although the third most frequent aneurysm in the abdomen, after aneurysms of the aorta and iliac arteries, and most frequent aneurisms of visceral arteries, splenic artery aneurysms are rare, but not very rare. Thanks to the new imaging techniques, first of all ultrasonography, they have been discovered with increasing frequency. We present a series of 9 splenic artery aneurysms. Seven patients were female and two male of average age 49 years (ranging from 28 to 75 years). The majority of afected women were multiparae, with average 3 children (ranging from 1 to 6). One patient had a subacute rupture, and 2 had ruptures into the splenic vein causing portal hypertension. The spleen was enlarged in 7 out of 9 patients. The average size of aneurysms was 3,2 cm (ranging from 2 to 8 cm). The preoperative diagnosis of splenic artery aneurysm was established in 6 patients while in 3 patients aneurism was accidentally found during other operations, during splenectomy in 2, and during the excision of a retroperitoneal tumour in 1 patient. Aneurysmectomy was carried out in 7 patients, while a ligation of the incoming and outcoming wessels was performed in 2 patients with arteriovenous fistula. Splenectomy was performed in 6 patients, while pancreatic tail resection, cholecystectomy and excision of the retroperitoneal tumor were performed in 3 patients. Additional resection of the abdominal aortic aneurysm with reconstruction of aortoiliac segment was performed in 2 patients. There were no mortality and the postoperative recovery was uneventful in all patients. PMID:16989145

  18. 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.

  19. 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.

  20. BILATERAL DUPLICATION OF RENAL ARTERIES

    Directory of Open Access Journals (Sweden)

    Prajkta A Thete

    2014-09-01

    Full Text Available Routine dissection of a male cadaver revealed the presence of bilateral double renal arteries. On the right side the accessory renal artery originated from the abdominal aorta just above the main renal artery. On the left side the accessory renal artery originated from the abdominal aorta about 1 cm above the main renal artery. Knowledge of the variations of renal vascular anatomy has importance in exploration and treatment of renal trauma, renal transplantation, renal artery embolization, surgery for abdominal aortic aneurysm and conservative or radical renal surgery

  1. 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.

  2. Structured Tree Outflow Condition for Blood Flow in Arteries

    Science.gov (United States)

    Olufsen, Mette

    1998-11-01

    Modeling blood flow and especially propagation of the pulse wave in the systemic arteries is of interests to the medical society because of the significance of the dicrotic wave. The pulse wave propagating along the larger arteries is reflected because of tapering and branching of the vessels, as well as the peripheral resistance, which is mainly stemming from the smaller arteries and arterioles. In order to avoid artificial reflections it is important to determine a boundary condition, representing the smaller arteries and arterioles, which is physiologically correct. In this work we have proposed a boundary condition based on a structured tree model. The result will be compared both with other modeling approaches as well as with results from measurements of flow and pressure at a number of locations along the larger arteries. The model for the larger arteries is based on the axisymmetrical Navier Stokes equations where the blood is assumed Newtonian and incompressible and the vessels are tapering. In the structured tree the model is based on a linearization of the axisymmetrical Navier-Stokes equations. The reason for setting up a structured tree is that the smaller arteries consist of an almost binary tree. Furthermore, the role of the smaller arteries is to allow blood perfusion of specific tissues. This is done in a structured and optimal way such that the smaller arteries cover the tissue evenly using a minimization principle.

  3. 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.

  4. 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.

  5. Anomalous right coronary artery arising from left anterior descending artery

    Directory of Open Access Journals (Sweden)

    M.L. Sreenivas Kumar

    2012-07-01

    Full Text Available A 54-year-old male patient presented with acute myocardial infarction involving left anterior descending and right coronary artery territories. Coronary angiogram showed a single coronary artery with right coronary artery arising from left anterior descending artery (LAD, which coursed anterior to right ventricular outflow tract and thrombotic lesion in mid left anterior descending artery before origin of right coronary artery. The patient was treated with thrombolytic therapy and glycoprotein IIb/IIIa inhibitors. Anomalous origin of right coronary artery as a branch of LAD is a very rare type of congenital coronary artery anomalies. It is important to recognize this anomaly as it can be associated with extensive myocardial ischemia and sudden cardiac death in young persons even without atherosclerosis.

  6. 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.

  7. 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

  8. 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 ...

  9. 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

  10. Finite Temperature Quark Confinement

    OpenAIRE

    Meisinger, Peter N.; Ogilvie, Michael C.

    1997-01-01

    Confinement may be more easily demonstrated at finite temperature using the Polyakov loop than at zero temperature using the Wilson loop. A natural mechanism for confinement can arise via the coupling of the adjoint Polyakov loop to F_{mu nu}^2. We demonstrate this mechanism with a one-loop calculation of the effective potential for SU(2) gluons in a background field consisting of a non-zero color magnetic field and a non-trivial Polyakov loop. The color magnetic field drives the Polyakov loo...

  11. 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...

  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. Visceral periadventitial adipose tissue regulates arterial tone of mesenteric arteries.

    Science.gov (United States)

    Verlohren, Stefan; Dubrovska, Galyna; Tsang, Suk-Ying; Essin, Kirill; Luft, Friedrich C; Huang, Yu; Gollasch, Maik

    2004-09-01

    Periadventitial adipose tissue produces vasoactive substances that influence vascular contraction. Earlier studies addressed this issue in aorta, a vessel that does not contribute to peripheral vascular resistance. We tested the hypothesis that periadventitial adipose tissue modulates contraction of smaller arteries more relevant to blood pressure regulation. We studied mesenteric artery rings surrounded by periadventitial adipose tissue from adult male Sprague-Dawley rats. The contractile response to serotonin, phenylephrine, and endothelin I was markedly reduced in intact vessels compared with vessels without periadventitial fat. The contractile response to U46619 or depolarizing high K+-containing solutions (60 mmol/L) was similar in vessels with and without periadventitial fat. The K+ channel opener cromakalim induced relaxation of vessels precontracted by serotonin but not by U46619 or high K+-containing solutions (60 mmol/L), suggesting that K+ channels are involved. The intracellular membrane potential of smooth muscle cells was more hyperpolarized in intact vessels than in vessels without periadventitial fat. Both the anticontractile effect and membrane hyperpolarization of periadventitial fat were abolished by inhibition of delayed-rectifier K+ (K(v)) channels with 4-aminopyridine (2 mmol/L) or 3,4-diaminopyridine (1 mmol/L). Blocking other K+ channels with glibenclamide (3 micromol/L), apamin (1 micromol/L), iberiotoxin (100 nmol/L), tetraethylammonium ions (1 mmol/L), tetrapentylammonium ions (10 micromol/L), or Ba2+ (3 micromol/L) had no effect. Longitudinal removal of half the perivascular tissue reduced the anticontractile effect of fat by almost 50%, whereas removal of the endothelium had no effect. We suggest that visceral periadventitial adipose tissue controls mesenteric arterial tone by inducing vasorelaxation via K(v) channel activation in vascular smooth muscle cells. PMID:15302842

  14. ARTERIAL ELASTICITY IN AMERICAN INDIAN AND CAUCASIAN CHILDREN, ADOLESCENTS, AND YOUNG ADULTS

    OpenAIRE

    Gardner, Andrew W; Parker, Donald E.

    2011-01-01

    We compared arterial elasticity in American Indian and Caucasian children, adolescents, and young adults, and we assessed whether demographic, body composition, and ambulatory activity measures were predictive of arterial elasticity within each group. Fifty-one American Indians and 66 Caucasians between the ages of 8 and 30 years were assessed on large artery elasticity index, small artery elasticity index, body fat percentage, and daily ambulatory activity during seven consecutive days. Amer...

  15. Transcutaneous measurement of the arterial input function in positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) provides a powerful tool in medical research. Biochemical function can be both precisely localized and quantitatively measured. To achieve reliable quantitation it is necessary to know the time course of activity concentration in the arterial blood during the measurement. In this study the arterial blood curve from the brachial artery is compared to the activity measured in the internal carotid artery with a new transcutaneous detector

  16. 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

  17. Intima-media thickness and arterial stiffness of carotid artery in Korean patients with Behçet's disease.

    Science.gov (United States)

    Rhee, Moo-Yong; Chang, Hyun Kyu; Kim, Seong-Kyu

    2007-06-01

    Behçet's disease (BD) is a systemic vasculitis involving diverse sizes of arteries and veins. We performed this study to evaluate the vascular changes by assessment of the arterial stiffness and intima-media thickness (IMT) of carotid artery in Korean patients with BD. Forty-one patients with BD and age-, and sex-matched 53 healthy subjects were recruited in this study. Carotid arterial stiffness and IMT were assessed by using high-resolution B-mode ultrasonography. Arterial stiffness parameters such as carotid arterial distensibility coefficient, stiffness index, and incremental elastic modulus (E(inc)) were significantly increased in BD patients compared with those in healthy subjects, but not in IMT. Positive relationship was noted between age and IMT, whereas age of onset was significantly associated with arterial stiffness in BD. This finding suggests impaired endothelial function before visible structural changes of arterial wall in BD. Age and age of onset may be an independent risk factor for carotid IMT and arterial stiffness, respectively. Further studies in more large populations are required to confirm our results. PMID:17596642

  18. 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).

  19. 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

  20. 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...

  1. 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\\

  2. 自然单元法与有限元法和无单元法的比较%Comparative study on natural element method, finite element method and meshless method

    Institute of Scientific and Technical Information of China (English)

    琚宏昌; 刘平伟; 张胜利

    2012-01-01

    In order to analyze the characteristics of the natural element method (NEM), comparison among NEM and the finite element method (FEM) and the meshless method (MM) is carried out. The basic principles of NEM is introduced in this paper, that is, NEM is based on the Voronoi tessellation of a set of nodes and the Delaunay triangulation of the topological dual of the Voronoi diagram, taking the natural neighbor interpolation as trial function and building the equilibrium equations to solve problems. NEM is considered to be a meshless method, and its shape functions can be constructed simply. By analyzing the basic properties of the three methods, the paper shows that the three methods have the same condition: partition of unity. Similar to FEM, NEM can exactly interpolate piece-wise linear boundary conditions. However, NEM is advantageous over the traditional FEM in solving problems with propagation of crack and large deformation and so on.%为了分析自然单元法的特点,进行了自然单元法与有限元法、无单元法的比较,介绍了自然单元法的基本原理,即基于点集的Voronoi图及其对偶Delaunay三角剖分,以自然邻节点为插值试函数,构建平衡方程进行求解.剖析了3种方法的基本性质,说明自然单元法、有限元法和无单元法均具有单位分解条件.认为自然单元法是一种无网格方法,其形函数构造简单,能与有限元法一样直接施加本质边界条件,可以求解有限元法较难处理的裂纹扩展和大变形等问题.

  3. 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

  4. Combination of rare right arterial variation with anomalous origins of the vertebral artery, aberrant subclavian artery and persistent trigeminal artery. A case report.

    Science.gov (United States)

    Ishihara, H; San Millán Ruíz, D; Abdo, G; Asakura, F; Yilmaz, H; Lovblad, K O; Rüfenacht, D A

    2011-09-01

    A 32-year-old woman hospitalized for subarachnoid hemorrhage showed rare arterial variation on the right side with anomalous origins of the vertebral artery, aberrant subclavian artery and persistent trigeminal artery. Angiography showed the right vertebral artery to originate from the right common carotid artery, the right subclavian artery to arise separately from the descending aorta, and persistent trigeminal artery on the right side. The possible embryonic mechanism of this previously unreported variant combination is discussed. PMID:22005696

  5. 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...

  6. 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.

  7. Comparative on comparison between central aortic pressure and brachial artery pressure of hypertension pa-tients in elderly%老年高血压患者中心动脉压与肱动脉压的对比分析

    Institute of Scientific and Technical Information of China (English)

    冬兰; 周冬翠; 尹秋生; 毕磊

    2015-01-01

    Objective To compare the difference between central aortic pressure and brachial artery pressure in elderly patients with hypertension.Methods One hundred and fifty-two elderly patients with hypertension were enrolled this study.The central aortic pressure of each patient was measured by Sphygmo Cor(Australia),respective-ly,and compared with brachial artery pressure.Results The brachial artery systolic pressure and pulse pressure were higher than central aortic systolic pressure and pulse pressure[(134.34 ±16.38)mm Hg vs.(116.21 ±14.71)mm Hg,(61.16 ±14.74)mm Hg vs.(37.55 ±7.92)mm Hg]and the difference was significant (P <0.01).But the brachial artery diastolic pressure was lower than central aortic diastolic pressure,the difference was significantly statis-tically (P <0.01).Compared with hypertension patients of grade-Ⅰ,systolic pressure and pulse pressure of brachial artery,augmentation pressure and augmentation index of central aortic were significantly higher in hypertension pa-tients of grade-Ⅲ (P <0.05).Conclusion There is significant difference between central aortic pressure and bra-chial artery pressure,it is necessary to measure the central aortic pressure for diagnosis and treatment of hypertension in elderly patients.%目的:对老年高血压患者的中心动脉压(CAP)和肱动脉血压进行对比分析,观察 CAP 与肱动脉压的差异。方法采用动脉脉搏波分析仪测量152例老年高血压患者的 CAP,并与肱动脉血压进行比较分析。结果老年高血压患者的肱动脉收缩压(SBP)、脉压(PP)显著高于中心动脉的收缩压(cSBP)、脉压(cPP)[(134.34±16.38)mm Hg 比(116.21±14.71)mm Hg;(61.16±14.74)mm Hg 比(37.55±7.92) mm Hg],而肱动脉舒张压(DBP)则显著低于中心动脉的舒张压(cDBP)[(73.03±9.66)mm Hg 比(79.34± 11.23)mm Hg],差异均有统计学意义(P <0.01)。与Ⅰ级高血压患者相

  8. Finite, primitive and euclidean spaces

    Directory of Open Access Journals (Sweden)

    Efim Khalimsky

    1988-01-01

    Full Text Available Integer and digital spaces are playing a significant role in digital image processing, computer graphics, computer tomography, robot vision, and many other fields dealing with finitely or countable many objects. It is proven here that every finite T0-space is a quotient space of a subspace of some simplex, i.e. of some subspace of a Euclidean space. Thus finite and digital spaces can be considered as abstract simplicial structures of subspaces of Euclidean spaces. Primitive subspaces of finite, digital, and integer spaces are introduced. They prove to be useful in the investigation of connectedness structure, which can be represented as a poset, and also in consideration of the dimension of finite spaces. Essentially T0-spaces and finitely connected and primitively path connected spaces are discussed.

  9. 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...

  10. Persistent Trigeminal Artery

    Directory of Open Access Journals (Sweden)

    Dijo T George

    2015-04-01

    Full Text Available Trigeminal artery is the commonest of the four primitive anastomoses between the carotid and vertebrobasilar system that may rarely persist in adults, with an angiographic incidence of 0.1 - 0.6%. We present the CT and MR angiograms of a patient who presented with a minor stroke and was detected to have this anomaly and briefly discuss the significance

  11. 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

  12. Finite element modelling

    International Nuclear Information System (INIS)

    The Finite Element Method (FEM) is a numerical technique for finding approximate solutions to boundary value problems. While FEM is commonly used to solve solid mechanics equations, it can be applied to a large range of BVPs from many different fields. FEM has been used for reactor fuels modelling for many years. It is most often used for fuel performance modelling at the pellet and pin scale, however, it has also been used to investigate properties of the fuel material, such as thermal conductivity and fission gas release. Recently, the United Stated Department Nuclear Energy Advanced Modelling and Simulation Program has begun using FEM as the basis of the MOOSE-BISON-MARMOT Project that is developing a multi-dimensional, multi-physics fuel performance capability that is massively parallel and will use multi-scale material models to provide a truly predictive modelling capability. (authors)

  13. Nonstandard finite difference schemes

    Science.gov (United States)

    Mickens, Ronald E.

    1995-01-01

    The major research activities of this proposal center on the construction and analysis of nonstandard finite-difference schemes for ordinary and partial differential equations. In particular, we investigate schemes that either have zero truncation errors (exact schemes) or possess other significant features of importance for numerical integration. Our eventual goal is to bring these methods to bear on problems that arise in the modeling of various physical, engineering, and technological systems. At present, these efforts are extended in the direction of understanding the exact nature of these nonstandard procedures and extending their use to more complicated model equations. Our presentation will give a listing (obtained to date) of the nonstandard rules, their application to a number of linear and nonlinear, ordinary and partial differential equations. In certain cases, numerical results will be presented.

  14. Basilar Artery Aneurysm at a Persistent Trigeminal Artery Junction

    Science.gov (United States)

    Aguiar, G.B.; Conti, M.L.M.; Veiga, J.C.E.; Jory, M.; Souza, R.B.

    2011-01-01

    Summary The trigeminal artery is an anastomosis between the embryonic precursors of the vertebrobasilar and carotid systems, and may persist into adult life. The association of the persistent primitive trigeminal artery (PTA) with cerebral aneurysm is well documented in the literature and, in general, aneurysms are located in the anterior circulation. We describe a patient who presented with a panencephalic Fisher III subarachnoid hemorrhage due to rupture of an intracranial aneurysm. Digital arteriography showed a saccular aneurysm in the middle third of the basilar artery, adjacent to the junction with a persistent trigeminal artery. She was submitted to endovascular treatment with embolization of the basilar artery aneurysm with coils. Aneurysms at the PTA junction with the basilar artery are rare. This paper describes a case of PTA associated with an aneurysm in the basilar artery at PTA junction and briefly reviews the literature. PMID:22005697

  15. 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.

  16. 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.

  17. 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.

  18. Renyi Entropy of the Ideal Gas in Finite Momentum Intervals

    CERN Document Server

    Bialas, A

    2003-01-01

    Coincidence probabilities of multiparticle events, as measured in finite momentum intervals for Bose and Fermi ideal gas, are calculated and compared with the exact expressions given in statistical physics.

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

    CERN Document Server

    Boshkayev, Kuantay; 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.

  20. 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.

  1. Remodelling of the microarchitecture of resistance arteries in cardiovascular diseases

    DEFF Research Database (Denmark)

    Bloksgaard, Maria; Brewer, Jonathan R.; Leurgans, Thomas;

    in comparison to other well-studied microvascular beds (e.g. rat mesentery). In the future we aim to compare the microarchitecture of small resistance arteries from parietal pericardial biopsies between patients with and without (treated) hypertension, diabetes and/or ischemic heart disease. 1. Buus, N.H., et...... is largely unknown, and the presented project aims to investigate this. Innovative multiphoton excitation microscopy will be applied on live (vital), isolated, cannulated and pressurized arteries from parietal pericardial biopsies obtained during open cardiac surgery (coronary artery bypass grafting......Small resistance artery structure is an independent predictor of cardiovascular events in essential hypertension [1, 2] and diabetes (types I and II) [3, 4]. In particular, the media-to-lumen ratio (M:L) is predictive of cardiovascular events. The exact nature of this resistance artery remodeling...

  2. Pulsatile flow of shear-dependent fluid in a stenosed artery

    Directory of Open Access Journals (Sweden)

    Mandal Shankar Mani

    2012-01-01

    Full Text Available This paper aims to investigate the blood flow in a bell-shaped constricted rigid tube, modeled as stenosed artery. The flow is assumed to be axi-symmetric, laminar and of oscillatory type. A mathematical model of shear-thinning fluid corresponding to the shear-dependent blood viscosity (mainly due to the behavior of the red blood cells in suspension of the flowing blood is considered. The governing equations of motion are presented with the help of stream function-vorticity and are solved numerically by finite-difference technique. The shear-thinning fluid model for the flowing blood has significant contribution in the dynamics of oscillatory blood flow. The results reveal that the arterial wall shear stress reduced significantly and the peak value of the wall shear stress at the maximum area reduction is comparatively low for Newtonian fluid viscosity. The lengths of recirculating regions formed after the constriction are reduced for the shear-thinning blood viscosity model and also for its different material parameters.

  3. 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.

  4. 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.

  5. 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.

  6. A unified approach to Mimetic Finite Difference, Hybrid Finite Volume and Mixed Finite Volume methods

    OpenAIRE

    Droniou, Jerome; Eymard,, Robert; Gallouët, Thierry; Herbin, Raphaele

    2008-01-01

    International audience We investigate the connections between several recent methods for the discretization of ani\\-so\\-tropic heterogeneous diffusion operators on general grids. We prove that the Mimetic Finite Difference scheme, the Hybrid Finite Volume scheme and the Mixed Finite Volume scheme are in fact identical up to some slight generalizations. As a consequence, some of the mathematical results obtained for each of the method (such as convergence properties or error estimates) may ...

  7. Hemodynamics of left internal mammary artery bypass graft: Effect of anastomotic geometry, coronary artery stenosis, and postoperative time.

    Science.gov (United States)

    Fan, Tingting; Lu, Yuan; Gao, Yan; Meng, Jie; Tan, Wenchang; Huo, Yunlong; Kassab, Ghassan S

    2016-03-21

    Although the left internal mammary artery (LIMA) bypass graft is the best choice for surgical revascularization, its hemodynamics are still complex and can result in long-term graft failure. Here, we performed a hemodynamic analysis of the LIMA-coronary artery with end-to-side/side-to-side anastomoses based on 15 patient-specific CTA images at various postoperative periods. We hypothesize that hemodynamic patterns are determined by the interplay of LIMA geometry, anastomotic configuration, and severity of native coronary artery stenosis, which are strongly affected by the postoperative time. A 3D finite volume method with the inlet pressure wave and outlet resistance boundary conditions was used to compute the distribution of pressure and flow, from which the time-averaged wall shear stress (TAWSS), oscillation shear index (OSI), time-averaged WSS gradient (TAWSSG), and transverse WSS (transWSS) were determined. To characterize the hemodynamic environment, we defined surface area ratios of low TAWSS (≤4dynes/cm(2)), high OSI (≥0.15), TAWSSG (≥500dynes/cm(3)), and transWSS (≥6dynes/cm(2)) in the LIMA graft and at the anastomosis between LIMA graft and coronary artery. These ratios were determined by the interplay of multiple morphometric parameters in the LIMA-coronary artery, but increased with postoperative time. These findings have significant implications for understanding LIMA graft patency. PMID:26900034

  8. Reactor kinetic formulation using the finite element method

    International Nuclear Information System (INIS)

    This research has the objective of solving the spatial Kinetic equations for two energy groups using the finite element method. In the methodology, was applied the direct method, such that matrix equations coefficients from spatial discretization was generated by finite element method. The formulation of the time-dependent problem was obtained by analytical integration of precursor concentration equation and using the Euler implicit scheme in the dynamic diffusion problem. A 2D example of a reactor static diffusion problem was solved using a linear triangular finite element. This solution was compared with the numerical benchmark solution, found in the literature, and the numerical results calculated by the finite difference methods. This comparison shows the capacity of the finite element method to obtain a precise solution. (author)

  9. 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...

  10. Finite strain discrete dislocation plasticity

    NARCIS (Netherlands)

    Deshpande, VS; Needleman, A; Van der Giessen, E

    2003-01-01

    A framework for carrying out finite deformation discrete dislocation plasticity calculations is presented. The discrete dislocations are presumed to be adequately represented by the singular linear elastic fields so that the large deformations near dislocation cores are not modeled. The finite defor

  11. 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.

  12. On stochastic finite difference schemes

    OpenAIRE

    Gyongy, Istvan

    2013-01-01

    Finite difference schemes in the spatial variable for degenerate stochastic parabolic PDEs are investigated. Sharp results on the rate of $L_p$ and almost sure convergence of the finite difference approximations are presented and results on Richardson extrapolation are established for stochastic parabolic schemes under smoothness assumptions.

  13. Stabilized Finite Elements with Matlab

    OpenAIRE

    Asensio, M. I.; A. Russo

    2002-01-01

    The purpose of this note is to explain the MATLAB code developed to solve an advection diffusion-reaction problem, with different Finite Element Methods: Standard Galerkin [7], Streamline Upwind/ Petrov-Galerkin (SUPG) [6], Unsual Stabilized [8, 9] and Residual-Free Bubbles [3, 4, 5], for both linear (P1) (see [1]) and quadratic (P2) (see [2]) triangular finite elements.

  14. 脉冲式及伪连续式动脉自旋标记技术静息态脑灌注对比研究%Comparative Study of Cerebral Perfusion by Using Pulsed and Pseudo Continuous Arterial Spin Labeling Techniques in Resting State

    Institute of Scientific and Technical Information of China (English)

    陈春晓; 郭超; 郑罡; 王利; 赵铁柱; 卢光明

    2013-01-01

    比较研究了脉冲式动脉自旋标记(pulsed arterial spin labeling,PASL)和伪连续式动脉自旋标记(pseudo continuous arterial spin labeling,pCASL)两种磁共振成像技术在静息态脑灌注中的应用.在静息态下,采用两种动脉自旋标记技术采集了10例健康志愿者的脑灌注数据,并计算脑血流量.两种技术的测量结果均显示,人脑默认网络中的楔前叶、角回、岛叶和后扣带回的相对脑血流量高于全脑平均灌注,而pCASL更敏感.在白质、额叶、顶叶、小脑和小脑蚓区域,pCASL和PASL测量得到的灌注值有显著性差异,除枕叶、小脑和小脑蚓外,PASL测量得到的灌注量小于pCASL.在全脑范围内,pCASL的信噪比明显高于PASL,且负灌注量很少.实验表明,pCASL可以提供比PASL更准确的测量结果.%The comparative study between pulsed arterial spin labeling (PASL) and pseudo continuous arterial spin labeling (pCASL) in resting cerebral perfusion were investigated. The PASL and pCASL data of 10 healthy subjects were acquired by a 3.0 T MR scanner during resting state, and the relative cerebral blood flows (rCBF) were then respectively quantified and analyzed. The results revealed that both techniques were able to detect the rCBF. CBFs in the precuneus, angular gyrus, insula, posterior cingulate cortex in default network were higher than the mean CBF in the whole brain, and pCASL was much more sensitive. Comparison with PASL sequence, CBFs obtained by the pCASL were significantly higher in white matter, frontal and parietal lobe, cerebellum and cerebellar vermis than that of PASL. Moreover, in the whole brain, higher SNR and less negative perfusion voxels were found in pCASL. The experimental results show that pCASL provides more accurate measurements than PASL in cerebral blood flow perfusion.

  15. 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).

  16. 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.

  17. 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.

  18. 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.

  19. Gestational pulmonary arterial hypertension

    OpenAIRE

    Moll, Matthew; Payne, Julie G.; Tukey, Melissa H.; Farber, Harrison W.

    2015-01-01

    Pulmonary arterial hypertension (PAH) is a progressive disease marked by the irreversible pulmonary vascular changes of vasoconstriction, thrombosis, and proliferation of smooth muscle and endothelial cells. The untreated clinical course is characterized by progressive dyspnea and a median survival of less than 3 years. Many of these patients are of child-bearing age; however, pregnancy leads to physiologic changes that are particularly poorly tolerated in PAH, conferring a 30%–56% mortality....

  20. CAROTID ARTERY DISEASE

    OpenAIRE

    Van Damme, H

    2009-01-01

    Carotid artery disease (CAD) become a commonly seen disease in general medical practice, due to the general population aging. Stroke, one of the most frequent complications of CAD and represents the third cause of death in Western countries. The leading cause of stroke in CAD is atheroembolism rather than flow-reduction. This paper reviewed imaging techniques, medical treatment and esepecially carotid endarterectomy (from point of view of indications, surgical technique and results) and caro...

  1. Myocardial arterial spin labeling

    OpenAIRE

    Kober, Frank; Jao, Terrence; Troalen, Thomas; Nayak, Krishna S.

    2016-01-01

    Arterial spin labeling (ASL) is a cardiovascular magnetic resonance (CMR) technique for mapping regional myocardial blood flow. It does not require any contrast agents, is compatible with stress testing, and can be performed repeatedly or even continuously. ASL-CMR has been performed with great success in small-animals, but sensitivity to date has been poor in large animals and humans and remains an active area of research. This review paper summarizes the development of ASL-CMR techniques, c...

  2. Finite-g Strings

    CERN Document Server

    Vicedo, Benoit

    2008-01-01

    In view of one day proving the AdS/CFT correspondence, a deeper understanding of string theory on certain curved backgrounds such as AdS_5xS^5 is required. In this dissertation we make a step in this direction by focusing on RxS^3. It was discovered in recent years that string theory on AdS_5xS^5 admits a Lax formulation. However, the complete statement of integrability requires not only the existence of a Lax formulation, but also that the resulting integrals of motion are in pairwise involution. This idea is central to the first part of this thesis. Exploiting this integrability we apply algebro-geometric methods to string theory on RxS^3 and obtain the general finite-gap solution. The construction is based on an invariant algebraic curve previously found in the AdS_5xS^5 case. However, encoding the dynamics of the solution requires specification of additional marked points. By restricting the symplectic structure of the string to this algebro-geometric data we derive the action-angle variables of the syste...

  3. Mimetic finite difference method

    Science.gov (United States)

    Lipnikov, Konstantin; Manzini, Gianmarco; Shashkov, Mikhail

    2014-01-01

    The mimetic finite difference (MFD) method mimics fundamental properties of mathematical and physical systems including conservation laws, symmetry and positivity of solutions, duality and self-adjointness of differential operators, and exact mathematical identities of the vector and tensor calculus. This article is the first comprehensive review of the 50-year long history of the mimetic methodology and describes in a systematic way the major mimetic ideas and their relevance to academic and real-life problems. The supporting applications include diffusion, electromagnetics, fluid flow, and Lagrangian hydrodynamics problems. The article provides enough details to build various discrete operators on unstructured polygonal and polyhedral meshes and summarizes the major convergence results for the mimetic approximations. Most of these theoretical results, which are presented here as lemmas, propositions and theorems, are either original or an extension of existing results to a more general formulation using polyhedral meshes. Finally, flexibility and extensibility of the mimetic methodology are shown by deriving higher-order approximations, enforcing discrete maximum principles for diffusion problems, and ensuring the numerical stability for saddle-point systems.

  4. Usefulness of multidetector-row CT (MD-CT) for assessment of coronary artery stenosis

    International Nuclear Information System (INIS)

    Coronary arteries stenosis were evaluated in 49 cases by volume rendering (VR) and partial maximum intensity projection (partial MIP) using multidetector-row CT (MD-CT). Left main trunk (LMT) and left anterior descending artery (LAD) were less affected by cardiac pulsation artifact and presented good images. Right coronary artery (RCA) was affected by cardiac pulsation artifact and image quality was inferior as compared to left coronary artery (LCA). It is suggested that MD-CT is useful for assessment of coronary artery stenosis, especially LCA. (author)

  5. 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.

  6. 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

  7. 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 ...

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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. PMID:20865459

  13. 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....

  14. 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)

  15. Finite element coiled cochlea model

    Science.gov (United States)

    Isailovic, Velibor; Nikolic, Milica; Milosevic, Zarko; Saveljic, Igor; Nikolic, Dalibor; Radovic, Milos; Filipović, Nenad

    2015-12-01

    Cochlea is important part of the hearing system, and thanks to special structure converts external sound waves into neural impulses which go to the brain. Shape of the cochlea is like snail, so geometry of the cochlea model is complex. The simplified cochlea coiled model was developed using finite element method inside SIFEM FP7 project. Software application is created on the way that user can prescribe set of the parameters for spiral cochlea, as well as material properties and boundary conditions to the model. Several mathematical models were tested. The acoustic wave equation for describing fluid in the cochlea chambers - scala vestibuli and scala timpani, and Newtonian dynamics for describing vibrations of the basilar membrane are used. The mechanical behavior of the coiled cochlea was analyzed and the third chamber, scala media, was not modeled because it does not have a significant impact on the mechanical vibrations of the basilar membrane. The obtained results are in good agreement with experimental measurements. Future work is needed for more realistic geometry model. Coiled model of the cochlea was created and results are compared with initial simplified coiled model of the cochlea.

  16. quadratic spline finite element method

    Directory of Open Access Journals (Sweden)

    A. R. Bahadir

    2002-01-01

    Full Text Available The problem of heat transfer in a Positive Temperature Coefficient (PTC thermistor, which may form one element of an electric circuit, is solved numerically by a finite element method. The approach used is based on Galerkin finite element using quadratic splines as shape functions. The resulting system of ordinary differential equations is solved by the finite difference method. Comparison is made with numerical and analytical solutions and the accuracy of the computed solutions indicates that the method is well suited for the solution of the PTC thermistor problem.

  17. Some Notes on Finite Sets

    OpenAIRE

    Preston, Chris

    2015-01-01

    These notes aim to give a gentle account to one approach to the theory of finite sets without making use of the natural numbers. They were written to be used as the basis for a student seminar. There are no real prerequisites except for a certain familiarity with the kind of mathematics seen in the first couple of years of a university mathematics course. The definition of being finite employed in these notes is usually called Kuratowski-finiteness and it is essentially that employed by White...

  18. Photon propagators at finite temperature

    International Nuclear Information System (INIS)

    We have used the real time formalism to compute the one-loop finite temperature corrections to the photon self energies in spinor and scalar QED. We show that, for a real photon, only the transverse components develop the temperature-dependent masses, while, for an external static electromagnetic field applied to the finite temperature system, only the static electric field is screened by thermal fluctuations. After showing how to compute systematically the imaginary parts of the finite temperature Green functions, we have attempted to give a microscopic interpretation of the imaginary parts of the self energies. (author)

  19. Smooth distributions are finitely generated

    CERN Document Server

    Drager, Lance D; Park, Efton; Richardson, Ken

    2010-01-01

    A subbundle of variable dimension inside the tangent bundle of a smooth manifold is called a smooth distribution if it is the pointwise span of a family of smooth vector fields. We prove that all such distributions are finitely generated, meaning that the family may be taken to be a finite collection. Further, we show that the space of smooth sections of such distributions need not be finitely generated as a module over the smooth functions. Our results are valid in greater generality, where the tangent bundle may be replaced by an arbitrary vector bundle.

  20. 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.

  1. 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.

  2. Non-Linear Finite Element Modeling of THUNDER Piezoelectric Actuators

    Science.gov (United States)

    Taleghani, Barmac K.; Campbell, Joel F.

    1999-01-01

    A NASTRAN non-linear finite element model has been developed for predicting the dome heights of THUNDER (THin Layer UNimorph Ferroelectric DrivER) piezoelectric actuators. To analytically validate the finite element model, a comparison was made with a non-linear plate solution using Von Karmen's approximation. A 500 volt input was used to examine the actuator deformation. The NASTRAN finite element model was also compared with experimental results. Four groups of specimens were fabricated and tested. Four different input voltages, which included 120, 160, 200, and 240 Vp-p with a 0 volts offset, were used for this comparison.

  3. Nonlinear finite element modeling of THUNDER piezoelectric actuators

    Science.gov (United States)

    Taleghani, Barmac K.; Campbell, Joel F.

    1999-06-01

    A NASTRAN non-linear finite element model has been developed for predicting the dome heights of THUNDER (Thin Layer Unimorph Ferroelectric Driver) piezoelectric actuators. To analytically validate the finite element model, a comparison was made with a non-linear plate solution using Von Karmen's approximation. A 500 volt input was used to examine the actuator deformation. The NASTRAN finite element model was also compared with experimental results. Four groups of specimens were fabricated and tested. Four different input voltages, which included 120, 160, 200, and 240 Vp-p with a 0 volts offset, were used for this comparison.

  4. 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.

  5. 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...

  6. Arterial mapping of lower limbs

    International Nuclear Information System (INIS)

    A bibliographic review is realized in the arterial mapping of lower limbs by ultrasonographic. The physical properties of the Doppler effect applied to diagnostic ultrasound are described. The anatomical characteristics of the general arterial system and specifically of the lower limbs arterial system are mentioned. Pathologies of the ischemic arterial disease of lower limbs are explained. The study characteristics of lower limbs arterial mapping are documented to determine its importance as appropriate method for the assessment of lower limb ischemia. An adequate arterial mapping of lower limbs is recognized in atherosclerotic ischemic disease as a reliable initial method alternative to arteriography. Arteriography is considered as reference pattern for therapeutic decision making in patients with critical ischemia of the lower limbs. Non-invasive methods to assess the arterial system of lower limbs has evidenced the advantages of the arterial mapping with Doppler, according to the consulted literature. The combination morphological and hemodynamic information has been possible and a map of the explored zone is made. The arterial mapping by ultrasonography has offered similar reliability to angiography

  7. Non-invasive diagnostic methods of intracranial arteries

    OpenAIRE

    Ramgren, Birgitta

    2014-01-01

    Aims of this thesis were to compare the agreement of different magnetic resonance angiography(MRA) techniques and digital subtraction angiography (DSA) in follow-up of intracranial aneurysms treated with coils in order to select the best MRA method, to evaluate the impact of increased iodine concentration in contrast medium and decreased tube voltage on arterial attenuation and image quality in computed tomography angiography (CTA) of intracranial arteries, and finally to evaluate the diag...

  8. An Ultrastructural Analysis of Collagen in Tissue Engineered Arteries

    OpenAIRE

    Dahl, Shannon L. M.; Vaughn, Megann E.; Niklason, Laura E.

    2007-01-01

    Collagen is the structural molecule that is most correlated with strength in blood vessels. In this study, we compared the properties of collagen in engineered and native blood vessels. Transmission electron microscopy (TEM) was used to image sections of engineered and native arteries. Band periodicities of engineered and native collagen fibrils indicated that spacing between collagen molecules was similar in engineered and native tissues. Engineered arteries, however, had thinner collagen fi...

  9. 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

  10. Order 1 autoregressive process of finite length

    CERN Document Server

    Vamos, Calin; Craciun, Maria

    2007-01-01

    The stochastic processes of finite length defined by recurrence relations request additional relations specifying the first terms of the process analogously to the initial conditions for the differential equations. As a general rule, in time series theory one analyzes only stochastic processes of infinite length which need no such initial conditions and their properties are less difficult to be determined. In this paper we compare the properties of the order 1 autoregressive processes of finite and infinite length and we prove that the time series length has an important influence mainly if the serial correlation is significant. These different properties can manifest themselves as transient effects produced when a time series is numerically generated. We show that for an order 1 autoregressive process the transient behavior can be avoided if the first term is a Gaussian random variable with standard deviation equal to that of the theoretical infinite process and not to that of the white noise innovation.

  11. Finite Element Analysis of Honeycomb Impact Attenuator

    Science.gov (United States)

    Yang, Seung-Yong; Choi, Seung-Kyu; Kim, Nohyu

    To participate in Student Formula Society of Automotive Engineers (SAE) competitions, it is necessary to build an impact attenuator that would give an average deceleration not to exceed 20g when it runs into a rigid wall. Students can use numerical simulations or experimental test data to show that their car satisfies this safety requirement. A student group to study formula cars at the Korea University of Technology and Education has designed a vehicle to take part in a SAE competition, and a honeycomb structure was adopted as the impact attenuator. In this paper, finite element calculations were carried out to investigate the dynamic behavior of the honeycomb attenuator. Deceleration and deformation behaviors were studied. Effect of the yield strength was checked by comparing the numerical results. ABAQUS/Explicit finite element code was used.

  12. 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.

  13. Finite dynamic deformations of smart structures

    Science.gov (United States)

    Batra, R. C.; Liang, X. Q.

    We study transient finite deformations of a neoHookean beam or plate with piezoelectric (PZT) patches bonded to its upper and lower surfaces. The constitutive relations for the PZTs are taken to be linear in the Green-Lagrange strain tensor but quadratic in the driving voltage. A finite element code using 8-noded brick elements has been developed and validated by comparing computed results with either analytical solutions or experimental observations. For flexural waves propagating through a cantilever beam, the sensor output is influenced a little by the presence of a defect placed symmetrically about the centroidal axis. A simple feedback control algorithm is shown to control the motion of a neoHookean plate subjected to an impulsive load.

  14. 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.

  15. Finite volume hydromechanical simulation in porous media

    OpenAIRE

    Nordbotten, Jan Martin

    2014-01-01

    Cell-centered finite volume methods are prevailing in numerical simulation of flow in porous media. However, due to the lack of cell-centered finite volume methods for mechanics, coupled flow and deformation is usually treated either by coupled finite-volume-finite element discretizations, or within a finite element setting. The former approach is unfavorable as it introduces two separate grid structures, while the latter approach loses the advantages of finite volume methods for the flow equ...

  16. 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.

  17. Supersymmetry at finite temperature revisited

    Energy Technology Data Exchange (ETDEWEB)

    Paranjape, M.B.; Taormina, A.; Wijewardhana, L.C.R.

    1983-05-02

    The authors have formulated sypersymmetry at finite temperature, generalizing the recent observations by Van Hove. They find that in a two-dimensional model broken supersymmetry is not restored at high temperature.

  18. Supersymmetry at Finite Temperature Revisited

    Science.gov (United States)

    Paranjape, M. B.; Taormina, A.; Wijewardhana, L. C. R.

    1983-05-01

    The authors have formulated supersymmetry at finite temperature, generalizing the recent observations by Van Hove. They find that in a two-dimensional model broken supersymmetry is not restored at high temperature.

  19. Purity Relative to Classes of Finitely Presented Modules

    OpenAIRE

    Mehdi, Akeel Ramadan

    2013-01-01

    Any set of finitely presented left modules defines a relative purity for left modules and also apurity for right modules. Purities defined by various classes are compared and investigated,especially in the contexts of modules over semiperfect rings and over tame hereditary, andmore general, finite-dimensional algebras. Connections between the indecomposable relativelypure-injective modules and closure in the full support topology (a refinement of theZiegler spectrum) are described.Duality bet...

  20. 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.

  1. 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.

  2. Isovector collective response function of nuclear matter at finite temperature

    International Nuclear Information System (INIS)

    We study isovector collective excitations in nuclear matter by employing the linearized Landau–Vlasov equation with and without a non-Markovian binary collision term at finite temperature. We calculate the giant dipole resonance (GDR) strength function for finite nuclei using the Steinwedel–Jensen model and also by Thomas–Fermi approximation, and we compare them for 120Sn and 208Pb with experimental results. (author)

  3. Quantum entanglement of localized excited states at finite temperature

    OpenAIRE

    Caputa, Pawel; Simón, Joan; Štikonas, Andrius(School of Mathematics and Maxwell Institute for Mathematical Sciences, University of Edinburgh, King’s Buildings, Edinburgh, EH9 3FD, U.K.); Takayanagi, Tadashi

    2015-01-01

    In this work we study the time evolutions of (Renyi) entanglement entropy of locally excited states in two dimensional conformal field theories (CFTs) at finite temperature.We consider excited states created by acting with local operators on thermal states and give both field theoretic and holographic calculations. In free field CFTs, we find that the growth of Renyi entanglement entropy at finite temperature is reduced compared to the zero temperature result by a small quantity proportional ...

  4. 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.

  5. [The single coronary artery].

    Science.gov (United States)

    Godart, F; Berzin, B; Rihani, R; Pecheux, M; Dutoit, A

    1992-04-01

    Single coronary artery is a fairly rare entity which may nevertheless be found in 0.4 per cent of coronary arteriograms. The authors report 3 cases seen in 2 departments of cardiology. In each patient, despite the existence of definite cardiovascular risk factors, this distribution was a factor worsening coronary ischemia, leading to complete thrombosis in one case. Although most often a chance discovery, a review of the literature justifies the attribution to this anomaly of the onset of angina, infarction or even sudden death. PMID:1642437

  6. Patent arterial duct

    OpenAIRE

    Martin Robin P; Elmasry Ola A; Forsey Jonathan T

    2009-01-01

    Abstract Patent arterial duct (PAD) is a congenital heart abnormality defined as persistent patency in term infants older than three months. Isolated PAD is found in around 1 in 2000 full term infants. A higher prevalence is found in preterm infants, especially those with low birth weight. The female to male ratio is 2:1. Most patients are asymptomatic when the duct is small. With a moderate-to-large duct, a characteristic continuous heart murmur (loudest in the left upper chest or infraclavi...

  7. Formal and finite order equivalences

    CERN Document Server

    Zaitsev, Dmitri

    2009-01-01

    We show that two families of germs of real-analytic subsets in $C^{n}$ are formally equivalent if and only if they are equivalent of any finite order. We further apply the same technique to obtain analogous statements for equivalences of real-analytic self-maps and vector fields under conjugations. On the other hand, we provide an example of two sets of germs of smooth curves that are equivalent of any finite order but not formally equivalent.

  8. Finite Size Corrections for Dimers

    CERN Document Server

    Nigro, Alessandro

    2012-01-01

    In this paper we derive the finite size corrections to the energy eigenvalues of the energy for 2D dimers on a square lattice. These finite size corrections, as in the case of Critical Dense Polymers, are proportional to the eigenvalues of the Local Integrals of Motion of Bazhanov Lukyanov and Zamolodchikov for central charge $c=-2$. This sheds more light on the status of the Dimer model as a conformal field theory with this value of the certral charge.

  9. 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.

  10. Comparison of Coronary Artery Bypass Grafting with Percutaneous Coronary Intervention for Unprotected Left Main Coronary Artery Disease

    OpenAIRE

    Kawecki, Damian; Morawiec, Beata; Fudal, Marcin; Milejski, Wojciech; Jacheć, Wojciech; Nowalany-Kozielska, Ewa

    2011-01-01

    Purpose Coronary artery bypass grafting (CABG) is the optimal treatment option for left main coronary artery disease (LMCAD). However, LMCAD remains a constant topic of discussion between cardiac surgeons and interventional cardiologists. The aim of this study was to assess the efficacy of LMCAD treatments by comparing the mid-term outcomes of CABG and percutaneous coronary intervention (PCI) using bare metal stents or drug-eluting stents (DESs). Materials and Methods The study population was...

  11. 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

  12. 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; PURL: http://www.clinicaltrials.gov. Unique identifier: NCT01666366. PMID:27406988

  13. True arterial system compliance estimated from apparent arterial compliance.

    Science.gov (United States)

    Quick, C M; Berger, D S; Hettrick, D A; Noordergraaf, A

    2000-03-01

    A new method has been developed to estimate total arterial compliance from measured input pressure and flow. In contrast to other methods, this method does not rely on fitting the elements of a lumped model to measured data. Instead, it relies on measured input impedance and peripheral resistance to calculate the relationship of arterial blood volume to input pressure. Generally, this transfer function is a complex function of frequency and is called the apparent arterial compliance. At very low frequencies, the confounding effect of pulse wave reflection disappears, and apparent compliance becomes total arterial compliance. This study reveals that frequency components of pressure and flow below heart rate are generally necessary to obtain a valid estimate of compliance. Thus, the ubiquitous practice of estimating total arterial compliance from a single cardiac cycle is suspect under most circumstances, since a single cardiac cycle does not contain these frequencies. PMID:10784093

  14. 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. ... All Open All Close All Description Pulmonary arterial hypertension is a progressive disorder characterized by abnormally high ...

  15. 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.

  16. 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

  17. Effects of simulated microgravity on arterial nitric oxide synthase and nitrate and nitrite content

    Science.gov (United States)

    Ma, Jin; Kahwaji, Chadi I.; Ni, Zhenmin; Vaziri, Nosratola D.; Purdy, Ralph E.

    2003-01-01

    The aim of the present work was to investigate the alterations in nitric oxide synthase (NOS) expression and nitrate and nitrite (NOx) content of different arteries from simulated microgravity rats. Male Wistar rats were randomly assigned to either a control group or simulated microgravity group. For simulating microgravity, animals were subjected to hindlimb unweighting (HU) for 20 days. Different arterial tissues were removed for determination of NOS expression and NOx. Western blotting was used to measure endothelial NOS (eNOS) and inducible NOS (iNOS) protein content. Total concentrations of NOx, stable metabolites of nitric oxide, were determined by the chemiluminescence method. Compared with controls, isolated vessels from simulated microgravity rats showed a significant increase in both eNOS and iNOS expression in carotid arteries and thoracic aorta and a significant decrease in eNOS and iNOS expression of mesenteric arteries. The eNOS and iNOS content of cerebral arteries, as well as that of femoral arteries, showed no differences between the two groups. Concerning NOx, vessels from HU rats showed an increase in cerebral arteries, a decrease in mesenteric arteries, and no change in carotid artery, femoral artery and thoracic aorta. These data indicated that there were differential alterations in NOS expression and NOx of different arteries after hindlimb unweighting. We suggest that these changes might represent both localized adaptations to differential body fluid redistribution and other factors independent of hemodynamic shifts during simulated microgravity.

  18. 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.

  19. [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.

  20. 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...

  1. Liver cirrhosis and arterial hypertension

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik; Møller, Søren

    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...... 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...

  2. Noninvasive measurements of arterial stiffness: Repeatability and interrelationships with endothelial function and arterial morphology measures

    Directory of Open Access Journals (Sweden)

    Corey J Huck

    2007-07-01

    Full Text Available Corey J Huck1, Ulf G Bronas1, Eric B Williamson1, Christopher C Draheim1, Daniel A Duprez2, Donald R Dengel1,31School of Kinesiology, University of Minnesota, Minneapolis, MN, USA; 2Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, MN; 3Research Service, Minneapolis Veterans Affairs Medical Center, Minneapolis, MN, USABackground: Many noninvasive arterial assessment techniques have been developed, measuring different parameters of arterial stiffness and endothelial function. However, there is little data available comparing different devices within the same subject. Therefore, the purpose of this study was to examine the repeatability and interrelationships between 3 different techniques to measure arterial stiffness and to compare this with forearm-mediated dilation.Methods: Carotid-radial pulse wave velocity was measured by the Sphygmocor (SPWV and Complior (CPWV devices, cardio-ankle vascular index (CAVI was measured by the VaSera device, vascular structure and function was assessed using ultrasonography and evaluated for reliability and compared in 20 apparently healthy, college-aged men and women.Results: The intraclass correlation coefficient and standard error of the mean for the Sphygmocor (R = 0.56, SEM = 0.69, Complior (R = 0.62, SEM = 0.69, and VaSera (R = 0.60, SEM = 0.56, indicated moderate repeatability. Bland-Altman plots indicated a mean difference of 0.11 ± 0.84 for SPWV, 0.13 ± 1.15 for CPWV, and –0.43 ± 0.90 for CAVI. No significant interrelationships were found among the ultrasound measures and SPWV, CPWV, and CAVI.Conclusions: The three noninvasive modalities to study arterial stiffness reliably measures arterial stiffness however, they do not correlate with ultrasound measures of vascular function and structure in young and apparently healthy subjects.Keywords: Pulse wave velocity, intima-media thickness, flow-mediated dilation

  3. Improved finite element forms for the shallow-water wave equations

    OpenAIRE

    Williams, R T; Zienkiewicz, O.C.

    1981-01-01

    This paper presents new finite element formulations of the shallow-water wave equations which use different basis functions for the velocity and height fields. These arrangements are analysed with the Fourier transform technique which was developed by Schoenstadt,' and they are also compared with other finite difference and finite element schemes. The new schemes are integrated in time for two initial states and compared with analytic solutions and numerical solutions from other s...

  4. 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

  5. On the Finite Volume Reformulation of the Mixed Finite Elements Method on Triangles

    OpenAIRE

    Chavent, Guy; Younès, Anis; Mosé, Robert; Ackerer, Philippe

    1999-01-01

    We analyse the finite volume reformulation of the triangular mixed finite element approximation for the porous flow equation, as proposed in [10] [9]. We show that the finite volumes are obtained by aggregation of finite elements (usually one, sometimes two or more), that the matrix of the finite volume equations is regular, but generally not symmetrical, and that the finite volume formulation is algebraically equivalent to the mixed approximation. The finite volume matrix becomes symmetrical...

  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. Patent arterial duct

    Directory of Open Access Journals (Sweden)

    Martin Robin P

    2009-07-01

    Full Text Available Abstract Patent arterial duct (PAD is a congenital heart abnormality defined as persistent patency in term infants older than three months. Isolated PAD is found in around 1 in 2000 full term infants. A higher prevalence is found in preterm infants, especially those with low birth weight. The female to male ratio is 2:1. Most patients are asymptomatic when the duct is small. With a moderate-to-large duct, a characteristic continuous heart murmur (loudest in the left upper chest or infraclavicular area is typical. The precordium may be hyperactive and peripheral pulses are bounding with a wide pulse pressure. Tachycardia, exertional dyspnoea, laboured breathing, fatigue or poor growth are common. Large shunts may lead to failure to thrive, recurrent infection of the upper respiratory tract and congestive heart failure. In the majority of cases of PAD there is no identifiable cause. Persistence of the duct is associated with chromosomal aberrations, asphyxia at birth, birth at high altitude and congenital rubella. Occasional cases are associated with specific genetic defects (trisomy 21 and 18, and the Rubinstein-Taybi and CHARGE syndromes. Familial occurrence of PAD is uncommon and the usual mechanism of inheritance is considered to be polygenic with a recurrence risk of 3%. Rare families with isolated PAD have been described in which the mode of inheritance appears to be dominant or recessive. Familial incidence of PAD has also been linked to Char syndrome, familial thoracic aortic aneurysm/dissection associated with patent arterial duct, and familial patent arterial duct and bicuspid aortic valve associated with hand abnormalities. Diagnosis is based on clinical examination and confirmed with transthoracic echocardiography. Assessment of ductal blood flow can be made using colour flow mapping and pulsed wave Doppler. Antenatal diagnosis is not possible, as PAD is a normal structure during antenatal life. Conditions with signs and symptoms of

  8. 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

  9. 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.

  10. Finite volume form factors in the presence of integrable defects

    Energy Technology Data Exchange (ETDEWEB)

    Bajnok, Z. [MTA Lendület Holographic QFT Group, Wigner Research Centre for Physics, H-1525 Budapest 114, P.O. Box 49 (Hungary); Buccheri, F. [MTA-BME “Momentum” Statistical Field Theory Research Group, Budafoki út 8, 1111 Budapest (Hungary); Hollo, L.; Konczer, J. [MTA Lendület Holographic QFT Group, Wigner Research Centre for Physics, H-1525 Budapest 114, P.O. Box 49 (Hungary); Takacs, G. [MTA-BME “Momentum” Statistical Field Theory Research Group, Budafoki út 8, 1111 Budapest (Hungary); Department of Theoretical Physics, Budapest University of Technology and Economics, Budafoki út 8, 1111 Budapest (Hungary)

    2014-05-15

    We developed the theory of finite volume form factors in the presence of integrable defects. These finite volume form factors are expressed in terms of the infinite volume form factors and the finite volume density of states and incorporate all polynomial corrections in the inverse of the volume. We tested our results, in the defect Lee–Yang model, against numerical data obtained by truncated conformal space approach (TCSA), which we improved by renormalization group methods adopted to the defect case. To perform these checks we determined the infinite volume defect form factors in the Lee–Yang model exactly, including their vacuum expectation values. We used these data to calculate the two point functions, which we compared, at short distance, to defect CFT. We also derived explicit expressions for the exact finite volume one point functions, which we checked numerically. In all of these comparisons excellent agreement was found.

  11. Application of the Finite Element Method to Rotary Wing Aeroelasticity

    Science.gov (United States)

    Straub, F. K.; Friedmann, P. P.

    1982-01-01

    A finite element method for the spatial discretization of the dynamic equations of equilibrium governing rotary-wing aeroelastic problems is presented. Formulation of the finite element equations is based on weighted Galerkin residuals. This Galerkin finite element method reduces algebraic manipulative labor significantly, when compared to the application of the global Galerkin method in similar problems. The coupled flap-lag aeroelastic stability boundaries of hingeless helicopter rotor blades in hover are calculated. The linearized dynamic equations are reduced to the standard eigenvalue problem from which the aeroelastic stability boundaries are obtained. The convergence properties of the Galerkin finite element method are studied numerically by refining the discretization process. Results indicate that four or five elements suffice to capture the dynamics of the blade with the same accuracy as the global Galerkin method.

  12. Finite Mordell-Tornheim multiple zeta values

    OpenAIRE

    Kamano, Ken

    2016-01-01

    We investigate a finite analogue of the Mordell-Tornheim multiple zeta values (the finite Mordell-Tornheim multiple zeta values). These values can be expressed by a linear combination of finite multiple zeta values, and its rules are described by the shuffle product. As a~corollary, we give a certain relation among finite multiple zeta values.

  13. 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…

  14. Lung effect on the hemodynamics in pulmonary artery

    Science.gov (United States)

    Tsai, S. F.; Sheu, Tony W. H.; Chang, T. M.

    2001-06-01

    The present study investigates blood flow in a pulmonary artery. The aim is to gain a better understanding of offset value in vascular circulation through a two-dimensional analysis of the Navier-Stokes equations. In this study, the hemodynamics in a blood vessel with truncated outlets at which constant pressure is specified is examined. To simplify the analysis, the vessel walls are regarded as being rigid. In quadratic elements, the streamline upwind Petrov-Galerkin finite element model is employed to simulate the incompressible Newtonian blood flow. The adopted finite element model introduces artificial damping terms solely in the streamline direction. With these terms added to the formulation, the discrete system is enhanced while solution accuracy is maintained without deterioration due to numerical diffusion errors. Copyright

  15. 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

  16. 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

  17. Automated carotid artery intima layer regional segmentation

    Science.gov (United States)

    Meiburger, Kristen M.; Molinari, Filippo; Rajendra Acharya, U.; Saba, Luca; Rodrigues, Paulo; Liboni, William; Nicolaides, Andrew; Suri, Jasjit S.

    2011-07-01

    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™ 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.

  18. 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.

  19. Surgical techniques of arterialized orthotopic liver transplantation in rats

    Institute of Scientific and Technical Information of China (English)

    MA Yi; WANG Guo-dong; GUO Zhi-yong; GUO Zhi-gang; HE Xiao-shun; CHEN Gui-hua

    2007-01-01

    Background Recently, much attention has been paid to hepatic artery reconstruction in rat liver transplantation, which can prevent bile duct ischemia and preserve better liver structure. In this study, three methods of graft arterialization,including sleeve, cuff, and stent anastomosis, were conducted and the results were compared.Methods Orthotopic liver transplantation (OLT) with rearterialization was conducted in 90 rats, which were divided into sleeve, cuff, and stent groups (n=30 in each). Ninety-six rats received OLTs with standardized two-cuff technique without rearterialization as a control. The sleeve technique included an end-to-end anastomosis between the donor common hepatic artery and recipient proper hepatic artery, or between the donor celiac artery and recipient common hepatic artery.Cuff technique involved an anastomosis between the donor common hepatic artery and recipient common hepatic artery.In the stent technique, the recipient hepatic artery and donor hepatic artery were connected using an intraluminal polyethylene stent. The arterial anastomosis time and arterial patency rate in each group were recorded. The liver graft survival and bile duct complication rates were measured.Results The total surgical time of OLT with rearterialization was (118.3±12.9) minutes in the sleeve group, (106.2±11.6)minutes in the cuff, (93.8±10.2) minutes in the stent, and (88.2±9.6) minutes in the control. The corresponding anhepatic phase was (19.6±2.8), (19.2±2.2), (18.6±1.8), and (20.0±2.5) minutes respectively in the sleeve, cuff, stent, and control groups. One-week survival rate was 86.5% in the control, and 86.7% in the groups with rearterialization. No significant difference was detected in the survival rate between them (P>0.05). The incidence of biliary complications in non-rearterialized group (17.7%) was significantly higher than that in the rearterialized group (6.7%, P<0.05). No significant difference was found in the incidence of biliary

  20. Left main coronary artery compression in pulmonary arterial hypertension

    DEFF Research Database (Denmark)

    Al-Badri, Kadhem Helo Abbas; Jensen, Jesper Møller; Christiansen, Evald H;

    2015-01-01

    In patients with pulmonary arterial hypertension (PAH), chest pain is most likely due to right ventricular demand ischemia. We report a patient with idiopathic PAH who developed severe angina due to extrinsic compression of the left main coronary artery (LMCA) from a dilated pulmonary artery trunk....... The diagnosis was verified by electrocardiogram after exercise, coronary angiography including intravascular ultrasound, and cardiac multidetector computed tomography (MDCT). The origin of the LMCA was high in the left coronary sinus, facilitating extrinsic compression. The patient was successfully treated...

  1. 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.

  2. 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. PMID:27216840

  3. A case of primitive persistent hypoglossal artery

    Energy Technology Data Exchange (ETDEWEB)

    Park, C. K.; Koh, B. H.; Kim, Y. S.; Kang, S. R. [Hangyang University College of Medicine, Seoul (Korea, Republic of)

    1979-06-15

    Three kinds of carotid-basilar anastomosis have been found, they were named as persistent primitive trigeminal artery, persistent primitive acoustic (or otic) artery and persistent primitive hypoglossal artery, among them, the persistent primitive hypoglossal artery is by far the least common type of the internal carotid-basilar anastomosis which have been demonstrate in human postembryonic stages. Persistent primitive by hypoglossal artery is usually found incidentally. This vascular anomaly, however,have been reported to be associated with multiple congenital anomalies, such as unilateral or bilateral vertebral artery hypoplasia, absence of the posterior communicating artery, hypoplasia of the proximal portion of the posterior cerebral artery, aneurysm of the circle of Willis, the origin of both pericallosal arteries from a single anterior cerebral artery, retarded mental development dating from infancy, carotid-cavernous fistula formation etc. A case of persistent primitive hypoglossal artery in an young Korean male was reported with brief review of the literature.

  4. The C-finite Ansatz

    CERN Document Server

    Zeilberger, Doron

    2011-01-01

    While it is trivial to multiply two C-finite sequences (just like integers), it is not quite so trivial to "factorize" them, or to decide whether they are "prime". The former is plain linear algebra, while the latter is heavy-duty non-linear algebra, getting hairy systems of algebraic equations that can be solved, in principle, using Gr\\"obner bases and the Buchberger algorithm, but, alas, sooner or later it becomes too hard even for the fastest and largest computers. The main technical novely of this article is a fast "algorithm" (it cheats and uses floating-point arithmetic, please don't tell anyone!) for deciding whether a given C-finite sequence can be written as a product of C-finite sequences of lower order. This article accompanies the Maple package Cfinite available from http://www.math.rutgers.edu/~zeilberg/tokhniot/Cfinite .

  5. 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 ...

  6. 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.

  7. Measurement of Blood Pressure Using an Arterial Pulsimeter Equipped with a Hall Device

    OpenAIRE

    Jong-Gu Choi; Keun-Ho Kim; Woo-Beom Lee; Dong-Hyun Nam; Il-Ho Son; You-Sik Hong; Sang-Suk Lee

    2011-01-01

    To measure precise blood pressure (BP) and pulse rate without using a cuff, we have developed an arterial pulsimeter consisting of a small, portable apparatus incorporating a Hall device. Regression analysis of the pulse wave measured during testing of the arterial pulsimeter was conducted using two equations of the BP algorithm. The estimated values of BP obtained by the cuffless arterial pulsimeter over 5 s were compared with values obtained using electronic or liquid mercury BP meters. The...

  8. Genes Involved in Systemic and Arterial Bed Dependent Atherosclerosis - Tampere Vascular Study

    OpenAIRE

    Mari Levula; Niku Oksala; Nina Airla; Rainer Zeitlin; Juha-Pekka Salenius; Otso Järvinen; Maarit Venermo; Teemu Partio; Jukka Saarinen; Taija Somppi; VeliPekka Suominen; Jyrki Virkkunen; Juha Hautalahti; Reijo Laaksonen; Mika Kähönen

    2012-01-01

    BACKGROUND: Atherosclerosis is a complex disease with hundreds of genes influencing its progression. In addition, the phenotype of the disease varies significantly depending on the arterial bed. METHODOLOGY/PRINCIPAL FINDINGS: We characterized the genes generally involved in human advanced atherosclerotic (AHA type V-VI) plaques in carotid and femoral arteries as well as aortas from 24 subjects of Tampere Vascular study and compared the results to non-atherosclerotic internal thoracic arterie...

  9. Assessment of normal and atherosclerotic arterial wall thickness with an intravascular ultrasound imaging catheter.

    OpenAIRE

    Mallery, JA; Tobis, JM; Griffith, J.; Gessert, J; McRae, M; Moussabeck, O; Bessen, M; Moriuchi, M; Henry, WL

    1990-01-01

    A prototype intravascular ultrasound imaging catheter with a 20 MHz transducer was used to obtain 59 cross-sectional images in 14 segments of human atherosclerotic arteries. Three distinct components of the arterial wall were visualized on the ultrasound images: a highly reflective intima, an echolucent media, and a moderately reflective adventitia. Images were obtained at 1 mm increments in vitro and were compared with histologic sections at the same levels. Measurements of the arterial laye...

  10. Effect of stenosed and occluded coronary arteries on immediate and late myocardial uptake of thallium-201.

    OpenAIRE

    Clitsakis, D; Layton, C A; Battersby, W; Johns, M; Stockley, A V

    1981-01-01

    Exercise and redistribution myocardial scintigraphy using thallium-201 was compared with the left ventricular angiogram and with the presence of stenosis or occlusion of coronary arteries on angiography. Irreversible scintigraphic defects representing areas of myocardial infarction were found in all patients with occlusion of the left anterior descending artery but nearly one-third of patients with stenosis of that artery also showed evidence of infarction. For the right coronary or circumfle...

  11. 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.

  12. Finite element solutions of free surface flows

    Science.gov (United States)

    Zarda, P. R.; Marcus, M. S.

    1977-01-01

    A procedure is presented for using NASTRAN to determine the flow field about arbitrarily shaped bodies in the presence of a free surface. The fundamental unknown of the problem is the velocity potential which must satisfy Laplace's equation in the fluid region. Boundary conditions on the free surface may involve second order derivatives in space and time. In cases involving infinite domains either a tractable radiation condition is applied at a truncated boundary or a series expansion is used and matched to the local finite elements. Solutions are presented for harmonic, transient, and steady state problems and compared to either exact solutions or other numerical solutions.

  13. Finite element simulation of asphalt fatigue testing

    DEFF Research Database (Denmark)

    Ullidtz, Per; Kieler, Thomas Lau; Kargo, Anders

    1997-01-01

    damage mechanics.The paper describes how continuum damage mechanics may be used with a finite element program to explain the progressive deterioration of asphalt mixes under laboratory fatigue testing. Both constant stress and constant strain testing are simulated, and compared to the actual results from...... three point and four point fatigue test on different mixes. It is shown that the same damage law, based on energy density, may be used to explain the gradual deterioration under constant stress as well as under constant strain testing.Some of the advantages of using this method for interpreting fatigue...

  14. A finite element model of ultrasonic extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, M [Department of Mechanical Engineering, University of Glasgow, G12 8QQ (United Kingdom); Daud, Y, E-mail: m.lucas@mech.gla.ac.u [College of Science and Technology, UTM City Campus, Kuala Lumpur (Malaysia)

    2009-08-01

    Since the 1950's researchers have carried out investigations into the effects of applying ultrasonic excitation to metals undergoing elastic and plastic deformation. Experiments have been conducted where ultrasonic excitation is superimposed in complex metalworking operations such as wire drawing and extrusion, to identify the benefits of ultrasonic vibrations. This study presents a finite element analysis of ultrasonic excitation applied to the extrusion of a cylindrical aluminium bar. The effects of friction on the extrusion load are reported for the two excitation configurations of radially and axially applied ultrasonic vibrations and the results are compared with experimental data reported in the literature.

  15. STUDY OF MEDIAL CIRCUMFLEX ARTERY

    Directory of Open Access Journals (Sweden)

    Pavan P Havaldar

    2014-06-01

    Full Text Available Background: The proper knowledge of the course and ramification of blood vessels of lower limbs is very important for surgeons and interventional radiologist. Medial circumflex femoral artery usually originates from posteromedial aspect of the profunda femoris, but often originates from femoral artery itself. It has an important role in supplying blood to femoral neck and head, fatty tissue in acetabular fossa and used in flaps reconstructive surgery. Methods: 50 adult lowerlimbs were procured from embalmed cadavers of J.J.M. Medical College and S.S.I.M.S & R.C, Davangere, Karnataka, India for the study. Dissection of femoral triangle was carried out according to Cunningham’s manual. Site and mode of origin of the branches of femoral artery were studied, configuration of the femoral origins of medial and lateral circumflex femoral artery and their prevalence were studied. Results: Out of 50 extremities, Medial circumflex femoral artery took origin from profunda femoris in 41 specimens and from femoral artery in 9 specimens. Conclusion: The knowledge of normal origin and variation of medial circumflex femoral artery is very valuable in preventing iatrogenic injury to these vessels during surgical procedures of femoral triangle.

  16. Anomalous Origin of Right Coronary Artery from Distal Left Circumflex Artery: A Very Rare Variant of Single Coronary Artery Anomaly

    OpenAIRE

    Arash Gholoobi

    2016-01-01

    Among coronary anomalies, Single Coronary Artery (SCA) is a rare anomaly in which one coronary artery stems from a single coronary ostium from the aortic sinuses, nourishing the entire heart. A very rare subtype of this anomaly is the anomalous origin of the Right Coronary Artery (RCA) from the distal Left Circumflex (LCx) artery.

  17. 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.

  18. 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.

  19. 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

  20. Formal and finite order equivalences

    OpenAIRE

    Zaitsev, Dmitri

    2009-01-01

    PUBLISHED We show that two families of germs of real-analytic subsets in Cn are formally equivalent if and only if they are equivalent of any finite order. We further apply the same technique to obtain analogous statements for equivalences of real-analytic self-maps and vector fields under conjugations. On the other hand, we provide an example of two sets of germs of smooth curves that are equivalent of any finite order but not formally equivalent. Supported in part by the Science Found...

  1. 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.)

  2. Access to the ophthalmic artery by retrograde approach through the posterior communicating artery for intra-arterial chemotherapy of retinoblastoma

    International Nuclear Information System (INIS)

    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.)

  3. Peripheral arterial stenosis and coronary artery disease coincidence

    Directory of Open Access Journals (Sweden)

    Reza Ghasemi

    2014-12-01

    Full Text Available Atherosclerosis is a chronic slow-developing condition affecting medium-size and large blood vessels. It is the principal underlying pathology of coronary heart disease and stroke. In some countries, coronary artery disease (CAD is the cause of nearly half (48% of the deaths and, loss of productivity life. Peripheral arterial disease (PAD is defined as atherosclerosis in peripheral arteries instead of coronary arteries. CAD and PAD have same risk factors and underlying pathophysiological processes. Therefore, patient with CAD should be considered for PAD. Ankle brachial index (ABI, duplex sonography, and some other non-invasive techniques are recommended for PAD diagnosis in patients with the history of CAD. Pharmacotherapy, endovascular interventions, and surgical management could be chosen according to the patient’s situation. Cardiologists and general practitioners should consider PAD in a patient with CAD or DM as a strong correlated disease.      

  4. 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.

  5. 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.

  6. Endovascular treatment of ectopic bronchial artery aneurysm with brachiocephalic artery stent placement and coil embolization

    Science.gov (United States)

    Di, Xiao; Ji, Dong-Hua; Chen, Yu; Liu, Chang-Wei; Liu, Bao; Yang, Juan

    2016-01-01

    Abstract Background: Bronchial artery aneurysm (BAA) is an uncommon but potentially life-threatening disease, and multiple BAAs are even rarer. Clinically, the tortuous and short neck of a BAA may present significant challenges for invasive intervention. Methods: This report describes the detailed process of diagnosis and treatment and includes a literature review of the etiology, clinical presentation, and therapeutic management of BAA. Results: A rare case of multiple BAAs, with one having an inflow artery arising from the brachiocephalic trunk, was referred to our hospital. The patient was successfully treated with coil embolization and brachiocephalic artery stent placement. In addition, we conducted a literature review involving 63 cases of BAA. BAA was most commonly associated with bronchiectasis and was located predominantly in the mediastinum. There was no significant difference between the diameters of the ruptured aneurysms and those of the nonruptured aneurysms (P = 0.115). Transcatheter arterial embolization was the most commonly adopted technique to treat BAA, while thoracic aortic endovascular repair was selected if the neck between the aneurysm and the aorta was short. Subgroup analysis suggested that patients with > 1 BAA were significantly more likely to be female than male (χ2 test, P = 0.034). Conclusion: Transcatheter coil embolization combined with stent placement could be a reasonable treatment option for BAAs with a tortuous and short neck. According to our literature review, patients with multiple BAAs display distinctive clinical characteristics compared with patients with a single BAA. PMID:27583854

  7. Local Intra-Arterial Fibrinolysis in Acute Basilar Artery Occlusion

    OpenAIRE

    Enomoto, Y.; Yoshimura, S.; Kitajima, H.; Tamakawa, N.; Iwama, T

    2007-01-01

    Acute basilar artery (BA) occlusion is typically associated with poor outcome; however newer diagnostic and treatment modalities have the potential to improve prognosis. In this study, six patients with acute BA occlusion were followed and the effectiveness of local intra-arterial fibrinolysis (LIF) and subsequent percutaneous transluminal angioplasty (PTA) with a balloon catheter were assessed. Of the six patients with BA occlusion observed in this study, two had extended brain stem infarcti...

  8. 大脑前动脉A1段的显微解剖与数字减影血管造影对照观测及临床意义%Microanatomy and digital subtraction angiography comparative observation of the A1 segment of anterior cerebral artery and its clinical significance

    Institute of Scientific and Technical Information of China (English)

    范锡印; 王怀彬; 付升旗; 赵东方; 苗莹莹

    2014-01-01

    anterior cerebral artery originated from its posterior and superior wall,the branches of the proximal,middle and distal segment were 2.55 ±0.39,0.52 ±0.46,and 1.12 ±0.10,respectively.There were significant differences in the perforators among the proximal,middle and distal segment (all P values < 0.05).The male A1 segment of anterior cerebral artery was longer than that of the female,there were significant differences in length and diameter respectively (all P values < 0.05).Conclusions Microanatomy and digital subtraction angiography comparative observation of the A1 segment of anterior cerebral artery has an important clinical significance for selecting the types and placing parts of vascular stent,avoiding obstruction the opening parts of perforators,preventing postoperative ischemia of the supply area of perforators.

  9. 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

  10. Peripheral artery disease in patients with coronary artery disease.

    Science.gov (United States)

    Atmer, B; Jogestrand, T; Laska, J; Lund, F

    1995-03-01

    The prevalence of peripheral vascular disease in patients with coronary artery disease has been investigated in many different ways and depends on the diagnostic methods and the definition of the atherosclerotic manifestations in the different vascular beds. In this study we used the non-invasive methods digital volume pulse plethysmography and ankle and toe blood pressure measurements to identify arterial abnormalities in the lower limbs in 58 patients (49 males and 9 females; age 37-72 years) examined with coronary angiography. The prevalence of peripheral artery disease was 22%, in agreement with the results of most previous investigations. There was a tendency towards increasing prevalence of peripheral artery disease with more advanced coronary artery disease: 14% of the patients with no or minimal coronary atheromotous lesions, 18% of the patients with moderate coronary atheromotous lesions and 32% of the patients with marked coronary atheromotous disease. For this reason a non-invasive investigation of the peripheral arterial circulation should be included early in the clinical consideration of patients with chest pain or similar symptoms suggesting coronary heart disease. Toe pressure measurement appears to be the most appropriate technique being rather simple in management and also in evaluation of results. PMID:7658111

  11. 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.

  12. [Variability of the celiac artery and its branches in sheep].

    Science.gov (United States)

    Karmona, Kh; Kovachev, G

    1985-01-01

    Contrast matter was used with a total of 363 sheep fetuses, newborn lambs, and adult sheep to study the variability of the coeliac artery and its branches. It was found that the artery and some of its branches, such as arteria ruminalis sinistra, arteria reticularis, and arteria lienalis often showed variations, resp., deviations in their branching and distribution. Others, such as arteria ruminalis dextra and arteria hepatica showed no variations whatever. Both the coeliac artery and the anterior intestinal artery in the sheep were most often shown to branch from the aorta alone (in 71.07 per cent of the cases) as against the rarely observed common truncus coeliacomesentericus (in 28.93 per cent of the cases). The most commonly observed form of branching of arteria coeliaca seemed to be tripus coeliacus, while the branching with the formation of a short truncus hepatogastricus was comparatively a rare phenomenon. It was also established that the left ruminal artery was much more frequently the branch of truncus lienoruminalis than the branch of arteria gastrica sinistra. So far as the place in which arteria reticularis arose three variants were observed. Most frequently this artery was shown to be the branch of arteria gastrica sinistra. PMID:4013078

  13. Arterial Stiffening and Clinical Outcomes in Dialysis Patients.

    Science.gov (United States)

    Kato, Akihiko

    2015-09-01

    Cardiovascular disease (CVD) is an important cause of morbidity and mortality in dialysis patients. Brachial-ankle pulse wave velocity (baPWV) is more efficient to handily assess arteriosclerosis than aortic PWV. The cardio-ankle vascular index (CAVI) is also a novel blood pressure-independent arterial stiffness parameter. In dialysis patients, both baPWV and CAVI are increased compared to general subjects. Several studies have demonstrated that increased baPWV is associated with carotid atherosclerosis and diastolic left ventricular dysfunction in hemodialysis (HD) patients. In addition, higher baPWV is related to all-cause and cardiovascular (CV) mortality. CAVI is similarly associated with CVD. However, baPWV is superior to CAVI as a predictor of CV outcomes in HD patients. Besides these outcomes, a close relationship exists between sarcopenia, abdominal visceral obesity and arterial stiffening. Reduction of thigh muscle mass is inversely correlated with baPWV and CAVI in males. Abdominal fatness is also associated with increased arterial stiffness in females. These observations provide further evidence of higher risk of CV events in HD patients with sarcopenic obesity. In addition, arterial stiffness is associated with cerebral small vessel disease and decreased cognitive function in the elderly. However, it is unknown whether arterial stiffness may be useful as an early indicator of cognitive decline in dialysis patients. Because dialysis patients are at risk of developing dementia, more studies are needed to elucidate the causal link between arterial stiffness and cognitive impairment. PMID:26587457

  14. 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

  15. 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.

  16. Pulmonary arterial hypertension.

    Science.gov (United States)

    Montani, David; Günther, Sven; Dorfmüller, Peter; Perros, Frédéric; Girerd, Barbara; Garcia, Gilles; Jaïs, Xavier; Savale, Laurent; Artaud-Macari, Elise; Price, Laura C; Humbert, Marc; Simonneau, Gérald; Sitbon, Olivier

    2013-01-01

    Pulmonary arterial hypertension (PAH) is a chronic and progressive disease leading to right heart failure and ultimately death if untreated. The first classification of PH was proposed in 1973. In 2008, the fourth World Symposium on PH held in Dana Point (California, USA) revised previous classifications. Currently, PH is devided into five subgroups. Group 1 includes patients suffering from idiopathic or familial PAH with or without germline mutations. Patients with a diagnosis of PAH should systematically been screened regarding to underlying mutations of BMPR2 gene (bone morphogenetic protein receptor type 2) or more rarely of ACVRL1 (activine receptor-like kinase type 1), ENG (endogline) or Smad8 genes. Pulmonary veno occusive disease and pulmonary capillary hemagiomatosis are individualized and designated as clinical group 1'. Group 2 'Pulmonary hypertension due to left heart diseases' is divided into three sub-groups: systolic dysfonction, diastolic dysfonction and valvular dysfonction. Group 3 'Pulmonary hypertension due to respiratory diseases' includes a heterogenous subgroup of respiratory diseases like PH due to pulmonary fibrosis, COPD, lung emphysema or interstitial lung disease for exemple. Group 4 includes chronic thromboembolic pulmonary hypertension without any distinction of proximal or distal forms. Group 5 regroup PH patients with unclear multifactorial mechanisms. Invasive hemodynamic assessment with right heart catheterization is requested to confirm the definite diagnosis of PH showing a resting mean pulmonary artery pressure (mPAP) of ≥ 25 mmHg and a normal pulmonary capillary wedge pressure (PCWP) of ≤ 15 mmHg. The assessment of PCWP may allow the distinction between pre-capillary and post-capillary PH (PCWP > 15 mmHg). Echocardiography is an important tool in the management of patients with underlying suspicion of PH. The European Society of Cardiology and the European Respiratory Society (ESC-ERS) guidelines specify its role

  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. 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...

  19. 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.

  20. 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.