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Sample records for arch aneurysm model

  1. Mycotic Aneurysm of the Aortic Arch

    Directory of Open Access Journals (Sweden)

    Ji Hye Seo

    2014-08-01

    Full Text Available A mycotic aneurysm of the thoracic aorta is rare. We report a case of mycotic aneurysm that developed in the aortic arch. An 86-year-old man was admitted with fever and general weakness. Blood culture yielded methicillin-resistant Staphylococcus aureus. Chest X-ray showed an enlarged aortic arch, and computed tomography scan revealed an aneurysm in the aortic arch. The patient was treated only with antibiotics and not surgically. The size of the aneurysm increased rapidly, resulting in bronchial obstruction and superimposed pneumonia. The patient died of respiratory failure.

  2. Dilatation of the aneurysmal sac after total arch replacement.

    Science.gov (United States)

    Watanuki, Hirotaka; Ogino, Hitoshi; Matsuda, Hitoshi; Minatoya, Kenji; Sasaki, Hiroaki; Fukuda, Tetsuya; Kitamura, Soichiro

    2008-02-01

    In our institution, total arch replacement for distal arch aneurysms is performed through a median sternotomy with antegrade selective cerebral perfusion. The distal anastomosis to the completely transected descending aorta is made through the aneurysmal sac. We report on three interesting cases presenting late dilatation of the aneurysmal sac due to collateral flow after total arch replacement.

  3. Aneurysm of the superficial palmar arch: a case report.

    Science.gov (United States)

    Estrella, Emmanuel P; Lee, Ellen Y

    2008-01-01

    Aneurysms of the hand are uncommon lesions. The most common location is the ulnar artery. We present a case of a young female who consulted us for a hand mass with a history of trauma to the hand. Pre-operative arteriogram showed a superficial palmar arch aneurysm. The mass was excised and the arch was reconstructed using a reversed Y-shaped vein graft. Fourteen months after surgery, there was no recurrence of the aneurysm and the patient only reported occasional cold intolerance.

  4. Right-sided aortic arch with Kommerell′s aneurysm

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    Sanjay Orathi Patangi

    2014-01-01

    Full Text Available We present a case report of a 55-year-old lady who presented with progressive dysphagia and was diagnosed with a Kommerell′s aneurysm and a right-sided aortic arch. This case report outlines our management strategy and the challenges encountered during the perioperative period in a patient with this rare anomaly.

  5. Importance of stent-graft design for aortic arch aneurysm repair

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    C Singh

    2017-02-01

    Full Text Available Aneurysm of the aorta is currently treated by open surgical repair or endovascular repair. However, when the aneurysm occurs in regions between the aortic arch and proximal descending aorta, it can be a complex pathology to treat due to its intricate geometry. When complex aortic aneurysms are treated with the conventional procedures, some of the patients present with significant post-operative complications and high mortality rate. Consequently, a clinically driven hybrid innovation known as the frozen elephant trunk procedure was introduced to treat complex aortic aneurysms. Although this procedure significantly reduces mortality rate and operating time, it is still associated with complications such as endoleaks, spinal cord ischemia, renal failure and stroke. Some of these complications are consequences of a mismatch in the biomechanical behaviour of the stent-graft device and the aorta. Research on complex aneurysm repair tended to focus more on the surgical procedure than the stent-graft design. Current stent-graft devices are suitable for straight vessels. However, when used to treat aortic aneurysm with complex geometry, these devices are ineffective in restoring the normal biological and biomechanical function of the aorta. A stent-graft device with mechanical properties that are comparable with the aorta and aortic arch could possibly lead to fewer post-operative complications, thus, better outcome for patients with complex aneurysm conditions. This review highlights the influence stent-graft design has on the biomechanical properties of the aorta which in turn can contribute to complications of complex aneurysm repair. Design attributes critical for minimising postoperative biomechanical mismatch are also discussed.

  6. Mouse models of intracranial aneurysm.

    Science.gov (United States)

    Wang, Yutang; Emeto, Theophilus I; Lee, James; Marshman, Laurence; Moran, Corey; Seto, Sai-wang; Golledge, Jonathan

    2015-05-01

    Subarachnoid hemorrhage secondary to rupture of an intracranial aneurysm is a highly lethal medical condition. Current management strategies for unruptured intracranial aneurysms involve radiological surveillance and neurosurgical or endovascular interventions. There is no pharmacological treatment available to decrease the risk of aneurysm rupture and subsequent subarachnoid hemorrhage. There is growing interest in the pathogenesis of intracranial aneurysm focused on the development of drug therapies to decrease the incidence of aneurysm rupture. The study of rodent models of intracranial aneurysms has the potential to improve our understanding of intracranial aneurysm development and progression. This review summarizes current mouse models of intact and ruptured intracranial aneurysms and discusses the relevance of these models to human intracranial aneurysms. The article also reviews the importance of these models in investigating the molecular mechanisms involved in the disease. Finally, potential pharmaceutical targets for intracranial aneurysm suggested by previous studies are discussed. Examples of potential drug targets include matrix metalloproteinases, stromal cell-derived factor-1, tumor necrosis factor-α, the renin-angiotensin system and the β-estrogen receptor. An agreed clear, precise and reproducible definition of what constitutes an aneurysm in the models would assist in their use to better understand the pathology of intracranial aneurysm and applying findings to patients.

  7. "Squid-capture" modified in situ stent-graft fenestration technique for aortic arch aneurysm repair.

    Science.gov (United States)

    Hongo, Norio; Miyamoto, Shinji; Shuto, Rieko; Wada, Tomoyuki; Kamei, Noritaka; Sato, Aiko; Matsumoto, Shunro; Kiyosue, Hiro; Mori, Hiromu

    2014-08-01

    An 83-year-old female was found to have an fusiform aneurysm in the aortic arch. She was deemed to be a high surgical risk; therefore, endovascular stent-graft placement followed by revascularization of the brachiocephalic trunk using in situ stent-graft fenestration was considered. However, the safe application of fenestration was deemed difficult due to the tortuosity of the brachiocephalic artery. The patient was successfully treated with the aid of the "squid-capture" technique, which consists of deployment of the stent-graft in a snare wire loop that was advanced from the brachiocephalic artery and fenestration of the stent-graft with the support of the loop. A follow-up exam revealed complete sealing of the aneurysm without any complications. The squid-capture technique allows for the safe and secure puncture of the graft.

  8. Medical image of the week: atherosclerotic aneurysm of aortic arch and descecnding thoracic aorta

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    Parasram M

    2016-02-01

    Full Text Available No abstract available. Article truncated after 150 words. A 94-year-old Spanish-speaking woman presented to the hospital with intermittent episodes of dyspnea and abdominal pain for one week. Her past medical history was notable for 30 pack-year smoking history and hypertension, which was reportedly controlled with medical therapy. Physical exam showed trace peripheral edema bilaterally, intact peripheral pulses, and a mild abdominal bruit. Work up at the emergency department revealed a non-ST elevation myocardial infarction with troponin T of 0.34 ng/mL but no ST-wave abnormality on electrocardiography. Chest x-ray displayed an incidental thoracic aneurysm (Figure 1. Chest computed tomography with contrast demonstrated a continuous aneurysm of the aortic arch and descending thoracic aorta with diameters measuring 6.8 cm and 6 cm, respectively (Figure 2A and 2B. Eccentric thrombi are noted in the aortic arch and the descending aorta. Interestingly, the distal descending thoracic aorta curves as it transitions to the abdominal aorta, which is evidence of a tortuous descending ...

  9. Fractionally Integrated Models With ARCH Errors

    OpenAIRE

    Hauser, Michael A.; Kunst, Robert M.

    1993-01-01

    Abstract: We introduce ARFIMA-ARCH models which simultaneously incorporate fractional differencing and conditional heteroskedasticity. We develop the likelihood function and a numerical estimation procedure for this model class. Two ARCH models - Engle- and Weiss-type - are explicitly treated and stationarity conditions are derived. Finite-sample properties of the estimation procedure are explored by Monte Carlo simulation. An application to the Standard & Poor 500 Index indicates existence o...

  10. Subject-specific modeling of intracranial aneurysms

    Science.gov (United States)

    Cebral, Juan R.; Hernandez, Monica; Frangi, Alejandro; Putman, Christopher; Pergolizzi, Richard; Burgess, James

    2004-04-01

    Characterization of the blood flow patterns in cerebral aneurysms is important to explore possible correlations between the hemodynamics conditions and the morphology, location, type and risk of rupture of intracranial aneurysms. For this purpose, realistic patient-specific models are constructed from computed tomography angiography and 3D rotational angiography image data. Visualizations of the distribution of hemodynamics forces on the aneurysm walls as well as the intra-aneurysmal flow patterns are presented for a number of cerebral aneurysms of different sizes, types and locations. The numerical models indicate that there are different classes of intra-aneurysmal flow patterns, that may carry different risks of rupture.

  11. A Binomial Integer-Valued ARCH Model.

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    Ristić, Miroslav M; Weiß, Christian H; Janjić, Ana D

    2016-11-01

    We present an integer-valued ARCH model which can be used for modeling time series of counts with under-, equi-, or overdispersion. The introduced model has a conditional binomial distribution, and it is shown to be strictly stationary and ergodic. The unknown parameters are estimated by three methods: conditional maximum likelihood, conditional least squares and maximum likelihood type penalty function estimation. The asymptotic distributions of the estimators are derived. A real application of the novel model to epidemic surveillance is briefly discussed. Finally, a generalization of the introduced model is considered by introducing an integer-valued GARCH model.

  12. Hybrid repair of penetrating aortic ulcer associated with right aortic arch and aberrant left innominate artery arising from aneurysmal Kommerell's diverticulum with simultaneous repair of bilateral common iliac artery aneurysms.

    Science.gov (United States)

    Guo, Yuanyuan; Yang, Bin; Cai, Hongbo; Jin, Hui

    2014-02-01

    We present the first case of a hybrid endovascular approach to a penetrating aortic ulcer on the left descending aorta with a right aortic arch and aberrant left innominate artery arising from an aneurysmal Kommerell's diverticulum. The patient also had bilateral common iliac artery aneurysms. The three-step procedure consisted of a carotid-carotid bypass, followed by endovascular exclusion of the ulcer and the aneurysmal Kommerell's diverticulum, and then completion by covering the iliac aneurysms. The patient had no complications at 18 months after surgery. In such rare configurations, endovascular repair is a safe therapeutic option.

  13. Modelling subset multivariate ARCH model via the AIC principle

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper we consider the problem of identifying a parsimonious subset multivariate ARCH model based on the AIC principle. The proposed approach can reduce the number of parameters in the final ARCH specification and allows for non-constant correlations between the components. Some simulation results illustrate the viability of the proposed procedure.

  14. A Functional Version of the ARCH Model

    CERN Document Server

    Hormann, Siegfried; Reeder, Ron

    2011-01-01

    Improvements in data acquisition and processing techniques have lead to an almost continuous flow of information for financial data. High resolution tick data are available and can be quite conveniently described by a continuous time process. It is therefore natural to ask for possible extensions of financial time series models to a functional setup. In this paper we propose a functional version of the popular ARCH model. We will establish conditions for the existence of a strictly stationary solution, derive weak dependence and moment conditions, show consistency of the estimators and perform a small empirical study demonstrating how our model matches with real data.

  15. Asymptotics of the QMLE for General ARCH(q) Models

    DEFF Research Database (Denmark)

    Kristensen, Dennis; Rahbek, Anders Christian

    2009-01-01

    Asymptotics of the QMLE for Non-Linear ARCH Models Dennis Kristensen, Columbia University Anders Rahbek, University of Copenhagen Abstract Asymptotic properties of the quasi-maximum likelihood estimator (QMLE) for non-linear ARCH(q) models -- including for example Asymmetric Power ARCH and log......-ARCH -- are derived. Strong consistency is established under the assumptions that the ARCH process is geometrically ergodic, the conditional variance function has a finite log-moment, and finite second moment of the rescaled error. Asymptotic normality of the estimator is established under the additional assumption...... that certain ratios involving the conditional variance function are suitably bounded, and that the rescaled errors have little more than fourth moment. We verify our general conditions, including identification, for a wide range of leading specific ARCH models....

  16. A novel arterial pouch model of saccular aneurysm by concomitant elastase and collagenase digestion

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Background: An ideal aneurysm model of cerebral aneurysm is of great importance for studying the pathogenesis of the lesion and testing new techniques for diagnosis and treatment. Several models have been created in rabbits and are now widely used in experimental studies; however, every model has certain intrinsic limitations. Here we report the development of a novel saccular aneurysm model in rabbits using an arterial pouch that is subject to in vitro pre-digestion with combined elastase and collagenase. Methods: A segment of right common carotid artery (CCA) was dissected out and treated with elastase (60 U/ml, 20 min) followed by type I collagenase (1 mg/ml, 15 min) in vitro. The graft was anastomosed to an arterial arch built with the left CCA and the remaining right CCA, while the other end of the graft was ligated. The dimension and tissue structure of the pouch were analysed immediately, 2 or 8 weeks after operation. Findings: Ten terminal aneurysms were produced. The gross morphology of the aneurysm resembles the human cerebral terminal aneurysms. We have observed the following pathological changes:(1) growth of the aneurysm (mean diameter increased from (2.0±0.1) to (3.2±0.3) mm at 2 weeks, P<0.001, n=7~10); (2) thinning of the aneurysmal wall (the mean wall thickness decreased to 44% at 2 weeks), which was accompanied by significant losses of elastic fibres, collagen and the cellular component; and (3) spontaneous rupture (3 out of 9, one aneurysm ruptured 24 h after operation with the other two at 2 and 4 weeks respectively). Conclusion: This rabbit arterial pouch model mimics human cerebral aneurysms in relation to morphology and histology. In particular, this model exhibited an increased tendency of spontaneous rupture.

  17. Mathematical model of a moment-less arch.

    Science.gov (United States)

    Lewis, W J

    2016-06-01

    This paper presents a mathematical model for predicting the geometrical shapes of rigid, two-pin, moment-less arches of constant cross section. The advancement of this work lies in the inclusion of arch self-weight and the ability to produce moment-less arch forms for any span/rise ratio, and any ratio of uniformly distributed load per unit span, w, to uniformly distributed arch weight per unit arch length, q. The model is used to derive the shapes of two classical 'moment-less' arch forms: parabolic and catenary, prior to demonstrating a general case, not restricted by the unrealistic load assumptions (absence of q, in the case of a parabolic form, or no w, in the case of a catenary arch). Using the same value of span/rise ratio, and w/q>1, the behaviour of the moment-less and parabolic arches under permanent loading, (w+q), is analysed. Results show the former to be developing much lower stresses than its parabolic rival, even when there are relatively small differences in the two geometries; for a medium span/rise ratio of 4 and w/q=2, differences in the parabolic and moment-less arch geometries would, in practical terms, be viewed as insignificant, but the stresses in them are different.

  18. Level-ARCH Short Rate Models with Regime Switching

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

    This paper introduces regime switching volatility into level- ARCH models for the short rates of the US, the UK, and Germany. Once regime switching and level effects are included there are no gains from including ARCH effects. It is of secondary importance exactly how the regime switching is spec...

  19. Surgical management of a hypoplastic distal aortic arch and coarctation of aorta in a patient with Klippel-Feil syndrome, ascending aortic aneurysm and bicuspid aortic valve.

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    Sabol, Frantisek; Kolesar, Adrián; Toporcer, Tomás; Bajmoczi, Milan

    2014-10-01

    Klippel-Feil syndrome has been associated with cardiovascular malformations, but only 3 cases have been reported to be associated with aortic coarctation and surgical management is not defined. A 51-year old woman with Klippel-Feil syndrome associated with an aneurysm of the ascending aorta, hypoplastic aortic arch and aortic coarctation at the level of the left subclavian artery presented with shortness of breath 2 years after diagnosis. Imaging identified interim development of a 7.2-cm aneurysm at the level of the aortic coarctation. She underwent surgical repair with a Dacron interposition graft under hypothermic circulatory arrest. She continues to do well 18 months following repair.

  20. Game model of safety monitoring for arch dam deformation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Arch dam deformation is comprehensively affected by water pressure,temperature,dam’s structural behavior and material properties as well as other factors.Among them the water pressure and temperature are external factors(source factors) that cause dam deformation,and dam’s structural behavior and material properties are the internal factors of deformation(resistance factors).The dam deformation is the result of the mutual game playing between source factors and resistance factors.Therefore,resistance factors of structure and materials that reflect resistance character of arch dam structure are introduced into the traditional model,where structure factor is embodied by the flexibility coefficient of dam body and the maximum dam height,and material property is embodied by the elastic modulus of dam.On the basis of analyzing the correlation between dam deformation and resistance factors,the game model of safety monitoring for arch dam deformation is put forward.

  1. Endovascular treatment of aortic arch aneurysms Tratamento endovascular dos aneurismas de arco aórtico

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    Roberto Chiesa

    2008-06-01

    Full Text Available BACKGROUND: Endovascular approach to the aortic arch is an appealing solution for selected patients. OBJECTIVE: To compare the technical and clinical success recorded in the different anatomical settings of endografting for aortic arch disease. METHODS: Between June 1999 and October 2006, among 178 patients treated at our institution for thoracic aorta disease with a stent-graft, the aortic arch was involved in 64 cases. According to the classification proposed by Ishimaru, aortic zone 0 was involved in 14 cases, zone 1 in 12 cases and zone 2 in 38 cases. A hybrid surgical procedure of supra-aortic debranching and revascularization was performed in 37 cases. RESULTS: Zone 0. Proximal neck length: 44±6 mm. Initial clinical success was 78.6%: two deaths (stroke, one type Ia endoleak. At a mean follow-up of 16.4±11 months the midterm clinical success was 85.7%. Zone 1. Proximal neck length: 28±5 mm. Initial clinical success was 66.7%: 0 deaths, four type Ia endoleaks. At a mean follow-up of 16.9±17.2 months the midterm clinical success was 75.0%. Zone 2. Proximal neck length: 30±5 mm. Initial clinical success was 84.2%: two deaths (one cardiac arrest, one multiorgan embolization, three type Ia endoleaks, one case of open conversion. Two cases of delayed transitory paraparesis/paraplegia were observed. At a mean follow-up of 28.0±17.2 months the midterm clinical success was 89.5%. CONCLUSIONS: This study and a literature review demonstrated that hybrid procedure for aortic arch pathology is feasible in selected patients at high risk for conventional surgery. Our experience is still limited by the relatively small sample size. We propose to reserve zone 1 for patients unfit for sternotomy or in cases with aortic neck length > 30 mm following left common carotid artery debranching. We recommend to perform complete aortic rerouting of the aortic arch in cases with lesser comorbidities and shorter aortic neck.CONTEXTO: O tratamento endovascular

  2. From bench to bedside: utility of the rabbit elastase aneurysm model in preclinical studies of intracranial aneurysm treatment.

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    Brinjikji, Waleed; Ding, Yong H; Kallmes, David F; Kadirvel, Ramanathan

    2016-05-01

    Preclinical studies are important in helping practitioners and device developers improve techniques and tools for endovascular treatment of intracranial aneurysms. Thus an understanding of the major animal models used in such studies is important. The New Zealand rabbit elastase induced arterial aneurysm of the common carotid artery is one of the most commonly used models in testing the safety and efficacy of new endovascular devices. In this review we discuss: (1) the various techniques used to create the aneurysm, (2) complications of aneurysm creation, (3) natural history of the arterial aneurysm, (4) histopathologic and hemodynamic features of the aneurysm, (5) devices tested using this model, and (6) weaknesses of the model. We demonstrate how preclinical studies using this model are applied in the treatment of intracranial aneurysms in humans. The model has similar hemodynamic, morphological, and histologic characteristics to human aneurysms, and demonstrates similar healing responses to coiling as human aneurysms. Despite these strengths, however, the model does have many weaknesses, including the fact that the model does not emulate the complex inflammatory processes affecting growing and ruptured aneurysms. Furthermore, the extracranial location of the model affects its ability to be used in preclinical safety assessments of new devices. We conclude that the rabbit elastase model has characteristics that make it a simple and effective model for preclinical studies on the endovascular treatment of intracranial aneurysms, but further work is needed to develop aneurysm models that simulate the histopathologic and morphologic characteristics of growing and ruptured aneurysms.

  3. The NIG-S&ARCH Model

    DEFF Research Database (Denmark)

    Jensen, Morten Berg; Lunde, Asger

    2001-01-01

    This paper examines the capabilities of the Normal Inverse Gaussian distribution as a model for stock returns. We extend the model of Barndorff-Nielsen (1997) to allow for a richer volatility structure and compare with the existing GARCH-type models. We conclude that the proportional model...... outperforms some of the most praised GARCH-M models. In particular, we make a big gain in modelling the skewness of equity returns...

  4. Modelling autogenous expansion for magnesia concrete in arch dams

    Institute of Scientific and Technical Information of China (English)

    Feng JIN; Guoxin ZHANG; Xiaoqing LUO; Chuhan ZHANG

    2008-01-01

    Magnesia Concrete is a kind of expansive con-crete used in Chinese hydraulic engineering more and more widely. To evaluate the effects of autogenous expan-sion on the stresses of arch dams, a simple model of auto-genous expansion for Magnesia Concrete in dam engineering is presented. This model is based on three assumptions: 1) the total amount of autogenous expan-sion of Magnesia Concrete is related only to the properties of materials and mixing of concrete; 2) the autogenous expansion of Magnesia Concrete is irreversible due to the irreversibility of hydration reaction of Magnesia in the concrete; 3) the autogenous expansion strain rates of Magnesia Concrete bear a relation between temperature and residual Magnesia per unit volume of concrete. The model is verified by some experimental data of autogen-ous expansion of Magnesia Concrete and field-measured data of an arch dam in China. Embedded into finite ele-ment arch dam simulation software, this model is employed to simulate the effects of autogenous expansion of Magnesia Concrete in hydraulic engineering.

  5. Thrombosis modeling in intracranial aneurysms: a lattice Boltzmann numerical algorithm

    Science.gov (United States)

    Ouared, R.; Chopard, B.; Stahl, B.; Rüfenacht, D. A.; Yilmaz, H.; Courbebaisse, G.

    2008-07-01

    The lattice Boltzmann numerical method is applied to model blood flow (plasma and platelets) and clotting in intracranial aneurysms at a mesoscopic level. The dynamics of blood clotting (thrombosis) is governed by mechanical variations of shear stress near wall that influence platelets-wall interactions. Thrombosis starts and grows below a shear rate threshold, and stops above it. Within this assumption, it is possible to account qualitatively well for partial, full or no occlusion of the aneurysm, and to explain why spontaneous thrombosis is more likely to occur in giant aneurysms than in small or medium sized aneurysms.

  6. PREDICTIVE CAPACITY OF ARCH FAMILY MODELS

    Directory of Open Access Journals (Sweden)

    Raphael Silveira Amaro

    2016-03-01

    Full Text Available In the last decades, a remarkable number of models, variants from the Autoregressive Conditional Heteroscedastic family, have been developed and empirically tested, making extremely complex the process of choosing a particular model. This research aim to compare the predictive capacity, using the Model Confidence Set procedure, than five conditional heteroskedasticity models, considering eight different statistical probability distributions. The financial series which were used refers to the log-return series of the Bovespa index and the Dow Jones Industrial Index in the period between 27 October 2008 and 30 December 2014. The empirical evidences showed that, in general, competing models have a great homogeneity to make predictions, either for a stock market of a developed country or for a stock market of a developing country. An equivalent result can be inferred for the statistical probability distributions that were used.

  7. A mathematical model of aortic aneurysm formation

    Science.gov (United States)

    Hao, Wenrui; Gong, Shihua; Wu, Shuonan; Xu, Jinchao; Go, Michael R.; Friedman, Avner; Zhu, Dai

    2017-01-01

    Abdominal aortic aneurysm (AAA) is a localized enlargement of the abdominal aorta, such that the diameter exceeds 3 cm. The natural history of AAA is progressive growth leading to rupture, an event that carries up to 90% risk of mortality. Hence there is a need to predict the growth of the diameter of the aorta based on the diameter of a patient’s aneurysm at initial screening and aided by non-invasive biomarkers. IL-6 is overexpressed in AAA and was suggested as a prognostic marker for the risk in AAA. The present paper develops a mathematical model which relates the growth of the abdominal aorta to the serum concentration of IL-6. Given the initial diameter of the aorta and the serum concentration of IL-6, the model predicts the growth of the diameter at subsequent times. Such a prediction can provide guidance to how closely the patient’s abdominal aorta should be monitored. The mathematical model is represented by a system of partial differential equations taking place in the aortic wall, where the media is assumed to have the constituency of an hyperelastic material. PMID:28212412

  8. Surgical repair of left-sided cervical aortic arch aneurysm%左颈位主动脉弓动脉瘤的外科治疗

    Institute of Scientific and Technical Information of China (English)

    郑铁; 朱俊明; 孙立忠; 钟永亮; 齐瑞东; 程力剑; 葛翼鹏; 陈雷; 刘巍; 里程楠; 邢晓燕

    2016-01-01

    目的:总结颈位主动脉弓(cervical aortic arch,CAA)动脉瘤的外科治疗方法及术后早中期效果。方法2010年1月至2014年12月,收治22例CAA动脉瘤患者,均为左位CAA。其中男6例,女16例,年龄(34.09±13.14)岁。术前合并主动脉假性狭窄9例,高血压3例,主动脉瓣反流、Stanford B型主动脉夹层、大脑中动脉瘤各1例。所有患者均采用人工血管替换术行主动脉弓重建。4例(4/22,18.18%)经胸骨正中切口,中度低温停循环、选择性顺行脑灌注下手术,其中同期行主动脉瓣置换术1例;18例(18/22,81.82%)经左后外侧第4肋间切口手术,其中10例体外循环辅助下实施手术,8例直接阻断下手术。结果全组平均呼吸机辅助(13.05±4.73) h,ICU停留(19.14±8.08) h。术后二次开胸止血1例,切口延迟愈合1例,一过性肝功能不全1例。无院内死亡。术后19例随访平均34.73个月,失访3例。随访期间无死亡。结论 CAA动脉瘤患者应积极手术治疗。根据CAA动脉瘤的位置、类型以及合并的其他近端心血管疾病,选择个体化的手术切口、辅助技术及手术方法,一期行主动脉弓重建手术治疗CAA动脉瘤可获得满意的临床效果。%Objective To summarize our experience of surgical repair for cervical aortic arch(CAA) aneurysm and eval-uate early and midterm results of these patients.Methods From January 2010 to December 2014, 22 patients with left-sided CAA aneurysm admitted in our center.There were 6 male and 16 female patients with a mean age of(34.09 ±13.14) years. Comorbidities included pseudocoarctation in 9 patients, hypertension in 4 patients, and aortic valve insufficiency, Stanford type B aortic dissection and middle cerebral artery aneurysm each had 1 patient.All of the patients underwent surgical aortic arch re-construction using artificial graft replacement.Among them, 4(4/22, 18.18%) were

  9. The murine angiotensin II-induced abdominal aortic aneurysm model: rupture risk and inflammatory progression patterns

    Directory of Open Access Journals (Sweden)

    Richard Y Cao

    2010-07-01

    Full Text Available An abdominal aortic aneurysm (AAA is an enlargement of the greatest artery in the body defined as an increase in diameter of 1.5-fold. AAAs are common in the elderly population and thousands die each year from their complications. The most commonly used mouse model to study the pathogenesis of AAA is the angiotensin II (Ang II infusion method delivered via osmotic mini-pump for 28 days. Here, we studied the site-specificity and onset of aortic rupture, characterized three-dimensional (3D images and flow patterns in developing AAAs by ultrasound imaging, and examined macrophage infiltration in the Ang II model using 65 apolipoprotein E deficient mice. Aortic rupture occurred in 16 mice (25 % and was nearly as prevalent at the aortic arch (44 % as it was in the suprarenal region (56 % and was most common within the first seven days after Ang II infusion (12 of 16; 75 %. Longitudinal ultrasound screening was found to correlate nicely with histological analysis and AAA volume renderings showed a significant relationship with AAA severity index. Aortic dissection preceded altered flow patterns and macrophage infiltration was a prominent characteristic of developing AAAs. Targeting the inflammatory component of AAA disease with novel therapeutics will hopefully lead to new strategies to attenuate aneurysm growth and aortic rupture.

  10. Development of the human aortic arch system captured in an interactive three-dimensional reference model.

    Science.gov (United States)

    Rana, M Sameer; Sizarov, Aleksander; Christoffels, Vincent M; Moorman, Antoon F M

    2014-06-01

    Variations and mutations in the human genome, such as 22q11.2 microdeletion, can increase the risk for congenital defects, including aortic arch malformations. Animal models are increasingly expanding our molecular and genetic insights into aortic arch development. However, in order to justify animal-to-human extrapolations, a human morphological, and molecular reference model would be of great value, but is currently lacking. Here, we present interactive three-dimensional reconstructions of the developing human aortic arch system, supplemented with the protein distribution of developmental markers for patterning and growth, including T-box transcription factor TBX1, a major candidate for the phenotypes found in patients with the 22q11.2 microdeletion. These reconstructions and expression data facilitate unbiased interpretations, and reveal previously unappreciated aspects of human aortic arch development. Based on our reconstructions and on reported congenital anomalies of the pulmonary trunk and tributaries, we postulate that the pulmonary arteries originate from the aortic sac, rather than from the sixth pharyngeal arch arteries. Similar to mouse, TBX1 is expressed in pharyngeal mesenchyme and epithelia. The endothelium of the pharyngeal arch arteries is largely negative for TBX1 and family member TBX2 but expresses neural crest marker AP2α, which gradually decreases with ongoing development of vascular smooth muscle. At early stages, the pharyngeal arch arteries, aortic sac, and the dorsal aortae in particular were largely negative for proliferation marker Ki67, potentially an important parameter during aortic arch system remodeling. Together, our data support current animal-to-human extrapolations and future genetic and molecular analyses using animal models of congenital heart disease. © 2013 Wiley Periodicals, Inc.

  11. The impact of deformation of an aneurysm model under pulsatile flow on hemodynamic analysis.

    Science.gov (United States)

    Kawakami, T; Takao, H; Ichikawa, C; Kamiya, K; Murayama, Y; Motosuke, M

    2016-08-01

    Hemodynamic analysis of cerebral aneurysms has been widely carried out to clarify the mechanisms of their growth and rupture. In several cases, patient-specific aneurysm models made of transparent polymers have been used. Even though periodic changes in aneurysms due to the pulsation of blood flow could be important, the deformation of the model geometry and its effect on hemodynamic evaluation has not been fully investigated. In addition, the fabrication accuracy of aneurysm models has not been evaluated even though it may affect the hemodynamic parameters to be analyzed. In this study, the fabrication accuracy of a silicone aneurysm model was investigated. Additionally, the deformation of the model under pulsatile flow as well as its correlation with flow behavior was evaluated. Consequently, a fabrication method for an aneurysm model with high accuracy was established and the importance of the wall thickness of the model was also specified.

  12. Early Diagnosis and Repair of Double Saccular Aneurysms of the Aortic Arch Associated With Aortic Coarctation in an Infant With Loeys-Dietz Syndrome.

    Science.gov (United States)

    Ilyin, Vladimir N; Kornoukhov, O Ju; Khovrin, Valery V; Kryukov, Vladislav A; Valitova, Asia A; Ilina, Maria V

    2016-03-01

    Multiple saccular aneurysms of the thoracic aorta in neonates and infants are exceedingly rare. An association of these aneurysms with Loeys-Dietz syndrome (LDS) in older age-groups is well known. This case report describes the diagnosis and subsequent successful repair of aortic coarctation associated with double saccular aneurysms of the thoracic aorta in patient with LDS during the first year of life.

  13. Endovascular Broad-Neck Aneurysm Creation in a Porcine Model Using a Vascular Plug

    Energy Technology Data Exchange (ETDEWEB)

    Muehlenbruch, Georg, E-mail: gmuehlenbruch@ukaachen.de; Nikoubashman, Omid; Steffen, Bjoern; Dadak, Mete [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, University Hospital (Germany); Palmowski, Moritz [RWTH Aachen University, Department of Nuclear Medicine, University Hospital (Germany); Wiesmann, Martin [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, University Hospital (Germany)

    2013-02-15

    Ruptured cerebral arterial aneurysms require prompt treatment by either surgical clipping or endovascular coiling. Training for these sophisticated endovascular procedures is essential and ideally performed in animals before their use in humans. Simulators and established animal models have shown drawbacks with respect to degree of reality, size of the animal model and aneurysm, or time and effort needed for aneurysm creation. We therefore aimed to establish a realistic and readily available aneurysm model. Five anticoagulated domestic pigs underwent endovascular intervention through right femoral access. A total of 12 broad-neck aneurysms were created in the carotid, subclavian, and renal arteries using the Amplatzer vascular plug. With dedicated vessel selection, cubic, tubular, and side-branch aneurysms could be created. Three of the 12 implanted occluders, two of them implanted over a side branch of the main vessel, did not induce complete vessel occlusion. However, all aneurysms remained free of intraluminal thrombus formation and were available for embolization training during a surveillance period of 6 h. Two aneurysms underwent successful exemplary treatment: one was stent-assisted, and one was performed with conventional endovascular coil embolization. The new porcine aneurysm model proved to be a straightforward approach that offers a wide range of training and scientific applications that might help further improve endovascular coil embolization therapy in patients with cerebral aneurysms.

  14. High arch

    Science.gov (United States)

    Pes cavus; High foot arch ... High foot arches are much less common than flat feet. They are more likely to be caused ... difficult to fit into shoes. People who have high arches most often need foot support. A high ...

  15. Stationary solution and parametric estimation for Bilinear model driven by ARCH noises

    Institute of Scientific and Technical Information of China (English)

    潘家柱; 李国栋; 谢衷洁

    2002-01-01

    Bilinear model driven by ARCH (1) noises is proposed. Existence, uniqueness and form of sta-tionary solution to this new model are presented. Maximum likelihood estimation of the model is discussedand some simulation results are given to evaluate our algorithm.

  16. Modeling and forecasting crude oil markets using ARCH-type models

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Chin Wen [Research Centre of Mathematical Sciences, Faculty of Information Technology, Multimedia University, 63100 Cyberjaya, Selangor (Malaysia)

    2009-06-15

    This study investigates the time-varying volatility of two major crude oil markets, the West Texas Intermediate (WTI) and Europe Brent. A flexible autoregressive conditional heteroskedasticity (ARCH) model is used to take into account the stylized volatility facts such as clustering volatility, asymmetric news impact and long memory volatility among others. The empirical results indicate that the intensity of long-persistence volatility in the WTI is greater than in the Brent. It is also found that for the WTI, the appreciation and depreciation shocks of the WTI have similar impact on the resulting volatility. However, a leverage effect is found in Brent. Although both the estimation and diagnostic evaluations are in favor of an asymmetric long memory ARCH model, only the WTI models provide superior in the out-of-sample forecasts. On the other hand, from the empirical out-of-sample forecasts, it appears that the simplest parsimonious generalized ARCH provides the best forecasted evaluations for the Brent crude oil data. (author)

  17. Asymptotic normality of the QMLE in the level-effect ARCH model

    DEFF Research Database (Denmark)

    Dahl, Christian Møller; Iglesias, Emma M.

    In this paper consistency and asymptotic normality of the quasi maximum like-lihood estimator in the level-effect ARCH model of Chan, Karolyi, Longstaff and Sanders (1992) is established. We consider explicitly the case where the parameters of the conditional heteroskedastic process...... are in the stationary region and discuss carefully how the results can be extended to the region where the conditional heteroskedastic process is nonstationary. The results illustrate that Jensen and Rahbek's (2004a,2004b) approach can be extended further than to traditional ARCH and GARCH models....

  18. Comparative study of dental arch width in plaster models, photocopies and digitized images

    Directory of Open Access Journals (Sweden)

    Maria Cristina Rosseto

    2009-06-01

    Full Text Available The aim of this study was to comparatively assess dental arch width, in the canine and molar regions, by means of direct measurements from plaster models, photocopies and digitized images of the models. The sample consisted of 130 pairs of plaster models, photocopies and digitized images of the models of white patients (n = 65, both genders, with Class I and Class II Division 1 malocclusions, treated by standard Edgewise mechanics and extraction of the four first premolars. Maxillary and mandibular intercanine and intermolar widths were measured by a calibrated examiner, prior to and after orthodontic treatment, using the three modes of reproduction of the dental arches. Dispersion of the data relative to pre- and posttreatment intra-arch linear measurements (mm was represented as box plots. The three measuring methods were compared by one-way ANOVA for repeated measurements (α = 0.05. Initial / final mean values varied as follows: 33.94 to 34.29 mm / 34.49 to 34.66 mm (maxillary intercanine width; 26.23 to 26.26 mm / 26.77 to 26.84 mm (mandibular intercanine width; 49.55 to 49.66 mm / 47.28 to 47.45 mm (maxillary intermolar width and 43.28 to 43.41 mm / 40.29 to 40.46 mm (mandibular intermolar width. There were no statistically significant differences between mean dental arch widths estimated by the three studied methods, prior to and after orthodontic treatment. It may be concluded that photocopies and digitized images of the plaster models provided reliable reproductions of the dental arches for obtaining transversal intra-arch measurements.

  19. Unsteady velocity measurements in a realistic intracranial aneurysm model

    Science.gov (United States)

    Ugron, Ádám; Farinas, Marie-Isabelle; Kiss, László; Paál, György

    2012-01-01

    The initiation, growth and rupture of intracranial aneurysms are intensively studied by computational fluid dynamics. To gain confidence in the results of numerical simulations, validation of the results is necessary. To this end the unsteady flow was measured in a silicone phantom of a realistic intracranial aneurysm. A flow circuit was built with a novel unsteady flow rate generating method, used to model the idealised shape of the heartbeat. This allowed the measurement of the complex three-dimensional velocity distribution by means of laser-optical methods such as laser doppler anemometry (LDA) and particle image velocimetry (PIV). The PIV measurements, available with high temporal and spatial distribution, were found to have good agreement with the control LDA measurements. Furthermore, excellent agreement was found with the numerical results.

  20. Characterization of the transport topology in patient-specific abdominal aortic aneurysm models

    Science.gov (United States)

    Arzani, Amirhossein; Shadden, Shawn C.

    2012-08-01

    Abdominal aortic aneurysm (AAA) is characterized by disturbed blood flow patterns that are hypothesized to contribute to disease progression. The transport topology in six patient-specific abdominal aortic aneurysms was studied. Velocity data were obtained by image-based computational fluid dynamics modeling, with magnetic resonance imaging providing the necessary simulation parameters. Finite-time Lyapunov exponent (FTLE) fields were computed from the velocity data, and used to identify Lagrangian coherent structures (LCS). The combination of FTLE fields and LCS was used to characterize topological flow features such as separation zones, vortex transport, mixing regions, and flow impingement. These measures offer a novel perspective into AAA flow. It was observed that all aneurysms exhibited coherent vortex formation at the proximal segment of the aneurysm. The evolution of the systolic vortex strongly influences the flow topology in the aneurysm. It was difficult to predict the vortex dynamics from the aneurysm morphology, motivating the application of image-based flow modeling.

  1. Collapse Modeling of a Masonry Arch Dam Using the Cohesive Interface Elements

    Directory of Open Access Journals (Sweden)

    Jianwen Pan

    2015-01-01

    Full Text Available A finite element (FE approach with zero-thickness cohesive interface elements is presented to simulate collapse of continuum structures. The element removal technique merged with the general contact algorithm is adapted in the FE approach to achieve modeling for a transition from continua to discontinua, that is, fracture, fragmentation, and collapse. Collapse process of Meihua masonry arch dam, which is a famous disaster in dam engineering in China, is simulated and the failure mechanism is studied. The collapse process obtained from the presented procedure coincides with the field observation after the dam failure. The failure of Meihua arch dam can be attributed to reducing shear strength of the peripheral joint between the dam body and the concrete pedestal by daubing a layer of asphalt there. With low sliding resistance strength, the masonry dam body may slide upwards along the peripheral joint under hydrostatic pressure, leading to weakening of the arch action, fracturing, and final collapse of the dam.

  2. Estimation and asymptotic inference in the first order AR-ARCH model

    DEFF Research Database (Denmark)

    Lange, Theis; Rahbek, Anders; Jensen, Søren Tolver

    2011-01-01

    This article studies asymptotic properties of the quasi-maximum likelihood estimator (QMLE) for the parameters in the autoregressive (AR) model with autoregressive conditional heteroskedastic (ARCH) errors. A modified QMLE (MQMLE) is also studied. This estimator is based on truncation of individual...... terms of the likelihood function and is related to the recent so-called self-weighted QMLE in Ling (2007b). We show that the MQMLE is asymptotically normal irrespectively of the existence of finite moments, as geometric ergodicity alone suffice. Moreover, our included simulations show that the MQMLE...... for the QMLE to be asymptotically normal. Finally, geometric ergodicity for AR-ARCH processes is shown to hold under mild and classic conditions on the AR and ARCH processes....

  3. Normalized least-squares estimation in time-varying ARCH models

    OpenAIRE

    Fryzlewicz, Piotr; Sapatinas, Theofanis; Subba Rao, Suhasini

    2008-01-01

    We investigate the time-varying ARCH (tvARCH) process. It is shown that it can be used to describe the slow decay of the sample autocorrelations of the squared returns often observed in financial time series, which warrants the further study of parameter estimation methods for the model. ¶ Since the parameters are changing over time, a successful estimator needs to perform well for small samples. We propose a kernel normalized-least-squares (kernel-NLS) estimator which has a closed form...

  4. COMPARISON OF CELLULOSE ACETATE POLYMER AND ELECTROLYTIC DETACHABLE COILS FOR TREATMENT OF CANINE ANEURYSMAL MODELS

    Institute of Scientific and Technical Information of China (English)

    杨新健; 吴中学; 李佑祥; 孙异临; 尹可

    2002-01-01

    Objective.Electrolytic detachable coils (EDC) have been the main embolic materials for intracranial aneurysms.Liquid aneurysmal embolic materials represented by cellulose acetate polymer (CAP) are still in controversy.In this research,the embolization results and pathological reactions after embolization of canine aneurysmal models with EDC or CAP were observed and compared. Methods.The canine aneurysmal models constructed by anastomosis of venous pouches were randomly grouped.The aneurysms were respectively occluded with CAP and electrolytic detachable coils that was named by Wu electrolytic detachable coil (WEDC) and made by us.Angiogram follow ups were performed at 24 hour,2 week,and 2 month after embolization.The occluded aneurysms were dissected in each stage for light microscopic,electron microscopic,and histochemical research. Results.The effect of embolization was significantly better with WEDC than that with CAP ( χ 2=5.56,P< 0.05) .Post embolized complications such as aneurysm rupture and stenosis of parent arteries could only be found in CAP group.Pathological research showed that CAP mass could packed the aneurysms more densely than coils.Acute chemical damage of aneurysmal wall and inflammatory cell infiltration was prominently found in early stage after CAP embolization.Organization of thrombus inside aneurysms and formation of endothelial tissue over the orifices of aneurysmal necks could be found in both groups 2 months after embolization.But parts of coils might be exposed outside endothelial layer. Conclusions.EDC are still the most safe,efficient,and reliable instruments to embolize aneurysm.CAP should be improved further to solve the problem of strong chemical corrosion and difficulty in control before it is widely used.

  5. Tratamento cirúrgico dos aneurismas e dissecções do arco aórtico Surgical treatment of aneurysms and dissections of the aortic arch

    Directory of Open Access Journals (Sweden)

    Bayard GONTIJO FILHO

    1999-10-01

    ; 31 patients were male (66.0% and ages ranged from 26-74 years (mean = 54.9 ± 10.9. Aortic dissection was present in 33 patients (70.2% and fusiform or sacular aneurysms in 14 (29.8%. Previous cardíac procedures had been performed in 11 patients (23.4%, rupture with cardíac tamponade was present in 4 patients. Median sternotomy was used in 42 cases and bilateral thoracotomy in 5. Deep hypothermia with circulatory arrest was used in 97.8% of cases with the arrest period ranging from 15 to 60 minutes (m = 30.6 ± 12.6. Anterior hemiarch reconstruction was used in 19 patients (40.4%, posterior hemiarch in 5 (10.6%, total arch replacement in 18 (38.3% aortoplasty in 4 (8.5% and extra-anatomic bypass with exclusion in 1 (2.1%. The main associated procedures were: myocardial revascularization (9, ascending aorta replacement by a valved conduit (15, elephant trunk (5 and aortic valve replacement (3. Hospital mortality was 12,3% (6 patients and respiratory insufficiency was the most common non-fatal complication (7 cases. Determinant factors for hospital mortality showed a statistical tendency for age over 60 years (p = 0.17 and for acute aortic dissection (p = 0.07. Late follow-up was achieved in 95.12% of the hospital survivors. There were 3 late deaths (1 cerebro-vascular accident, 2 reoperations. The 9 year survival rate is 80.85%.

  6. ARCH模型的诊断分析%Diagnose analysis in ARCH models

    Institute of Scientific and Technical Information of China (English)

    柯珂; 张世英

    2001-01-01

    探讨了ARCH模型的诊断分析和变结构建模问题.所提出的分整增广GARCH-M模型包括了几乎所有现有的ARCH模型,基于分整增广GARCH-M模型克服了ARCH模型在模型设定检验,长记忆检验和参数估计等方面的障碍.利用分段建模方法来检测模型结构变化点和分段变化模型的选择.最后,以上海证券综合事业股票指数为数据,验证了诊断分析方法的有效性.%The diagnose analysis and modeling problem with structure changein ARCH models are discussed in this paper.The paper proposses fractional integrated augmented GARCH-M model which can embrace almost all the current ARCH models. Based on the fractional integrated augmented GARCH-M model, the handicap in model specification test, long memory test and parameters estimation is oversome.The segment-modeling method is used to detect the structure changing points of the ARCH model and test the models for segment-changing models.Finally, with the composite index of closing price in Shanghai stock market, it is shown to illustrate the effectiveness of the diagnose analysis.

  7. Ambient modal testing of a double-arch dam: the experimental campaign and model updating

    Science.gov (United States)

    García-Palacios, Jaime H.; Soria, José M.; Díaz, Iván M.; Tirado-Andrés, Francisco

    2016-09-01

    A finite element model updating of a double-curvature-arch dam (La Tajera, Spain) is carried out hereof using the modal parameters obtained from an operational modal analysis. That is, the system modal dampings, natural frequencies and mode shapes have been identified using output-only identification techniques under environmental loads (wind, vehicles). A finite element model of the dam-reservoir-foundation system was initially created. Then, a testing campaing was then carried out from the most significant test points using high-sensitivity accelerometers wirelessly synchronized. Afterwards, the model updating of the initial model was done using a Monte Carlo based approach in order to match it to the recorded dynamic behaviour. The updated model may be used within a structural health monitoring system for damage detection or, for instance, for the analysis of the seismic response of the arch dam- reservoir-foundation coupled system.

  8. Animal Models Used to Explore Abdominal Aortic Aneurysms

    DEFF Research Database (Denmark)

    Lysgaard Poulsen, J; Stubbe, J; Lindholt, J S

    2016-01-01

    OBJECTIVE: Experimental animal models have been used to investigate the formation, development, and progression of abdominal aortic aneurysms (AAAs) for decades. New models are constantly being developed to imitate the mechanisms of human AAAs and to identify treatments that are less risky than...... those used today. However, to the authors' knowledge, there is no model identical to the human AAA. The objective of this systematic review was to assess the different types of animal models used to investigate the development, progression, and treatment of AAA and to highlight their advantages...... and limitations. METHODS: A search protocol was used to perform a systematic literature search of PubMed and Embase. A total of 2,830 records were identified. After selection of the relevant articles, 564 papers on animal AAA models were included. RESULTS: The most common models in rodents, including elastase...

  9. Bin-objective shape optimization based on linear programming model of arch dam

    Institute of Scientific and Technical Information of China (English)

    JIN Hai; LIN Gao; YANG Ming-sheng

    2007-01-01

    Bin-objective shape optimization of arch dam based on linear programming model is discussed to minimize both dam volume and maximal tensile stress. The importance of weight coefficient of the above two objectives is chosen according to the value of importance ratio. The influence of weight coefficient to the optimization result is discussed in detail and the numerical example shows that both the model and method proposed is doable.

  10. Finite element model for arch bridge vibration dynamics considering effect of suspender length adjustment on geometry stiffness matrix

    Institute of Scientific and Technical Information of China (English)

    ZHONG Yi-feng; WANG Rui; YING Xue-gang; CHEN Huai

    2006-01-01

    In this paper, we established a finite element (FEM) model to analyze the dynamic characteristics of arch bridges. In this model, the effects of adjustment to the length of a suspender on its geometry stiffness matrix are stressed. The FEM equations of mechanics characteristics, natural frequency and main mode are set up based on the first order matrix perturbation theory. Applicantion of the proposed model to analyze a real arch bridge proved the improvement in the simulation precision of dynamical characteristics of the arch bridge by considering the effects of suspender length variation.

  11. Variable-intercept panel model for deformation zoning of a super-high arch dam.

    Science.gov (United States)

    Shi, Zhongwen; Gu, Chongshi; Qin, Dong

    2016-01-01

    This study determines dam deformation similarity indexes based on an analysis of deformation zoning features and panel data clustering theory, with comprehensive consideration to the actual deformation law of super-high arch dams and the spatial-temporal features of dam deformation. Measurement methods of these indexes are studied. Based on the established deformation similarity criteria, the principle used to determine the number of dam deformation zones is constructed through entropy weight method. This study proposes the deformation zoning method for super-high arch dams and the implementation steps, analyzes the effect of special influencing factors of different dam zones on the deformation, introduces dummy variables that represent the special effect of dam deformation, and establishes a variable-intercept panel model for deformation zoning of super-high arch dams. Based on different patterns of the special effect in the variable-intercept panel model, two panel analysis models were established to monitor fixed and random effects of dam deformation. Hausman test method of model selection and model effectiveness assessment method are discussed. Finally, the effectiveness of established models is verified through a case study.

  12. Fast Virtual Stenting with Active Contour Models in Intracranical Aneurysm.

    Science.gov (United States)

    Zhong, Jingru; Long, Yunling; Yan, Huagang; Meng, Qianqian; Zhao, Jing; Zhang, Ying; Yang, Xinjian; Li, Haiyun

    2016-02-15

    Intracranial stents are becoming increasingly a useful option in the treatment of intracranial aneurysms (IAs). Image simulation of the releasing stent configuration together with computational fluid dynamics (CFD) simulation prior to intervention will help surgeons optimize intervention scheme. This paper proposed a fast virtual stenting of IAs based on active contour model (ACM) which was able to virtually release stents within any patient-specific shaped vessel and aneurysm models built on real medical image data. In this method, an initial stent mesh was generated along the centerline of the parent artery without the need for registration between the stent contour and the vessel. Additionally, the diameter of the initial stent volumetric mesh was set to the maximum inscribed sphere diameter of the parent artery to improve the stenting accuracy and save computational cost. At last, a novel criterion for terminating virtual stent expanding that was based on the collision detection of the axis aligned bounding boxes was applied, making the stent expansion free of edge effect. The experiment results of the virtual stenting and the corresponding CFD simulations exhibited the efficacy and accuracy of the ACM based method, which are valuable to intervention scheme selection and therapy plan confirmation.

  13. Density Forecasts of Crude-Oil Prices Using Option-Implied and ARCH-Type Models

    DEFF Research Database (Denmark)

    Tsiaras, Leonidas; Høg, Esben

      The predictive accuracy of competing crude-oil price forecast densities is investigated for the 1994-2006 period. Moving beyond standard ARCH models that rely exclusively on past returns, we examine the benefits of utilizing the forward-looking information that is embedded in the prices...... of derivative contracts. Risk-neutral densities, obtained from panels of crude-oil option prices, are adjusted to reflect real-world risks using either a parametric or a non-parametric calibration approach. The relative performance of the models is evaluated for the entire support of the density, as well...... obtained by option prices and non-parametric calibration methods over those constructed using historical returns and simulated ARCH processes....

  14. Density forecasts of crude-oil prices using option-implied and ARCH-type models

    DEFF Research Database (Denmark)

    Høg, Esben; Tsiaras, Leonicas

    2011-01-01

    The predictive accuracy of competing crude-oil price forecast densities is investigated for the 1994–2006 period. Moving beyond standard ARCH type models that rely exclusively on past returns, we examine the benefits of utilizing the forward-looking information that is embedded in the prices...... of derivative contracts. Risk-neutral densities, obtained from panels of crude-oil option prices, are adjusted to reflect real-world risks using either a parametric or a non-parametric calibration approach. The relative performance of the models is evaluated for the entire support of the density, as well...... obtained by option prices and non-parametric calibration methods over those constructed using historical returns and simulated ARCH processes. © 2010 Wiley Periodicals, Inc. Jrl Fut Mark...

  15. A quantitative method for defining high-arched palate using the Tcof1(+/-) mutant mouse as a model.

    Science.gov (United States)

    Conley, Zachary R; Hague, Molly; Kurosaka, Hiroshi; Dixon, Jill; Dixon, Michael J; Trainor, Paul A

    2016-07-15

    The palate functions as the roof of the mouth in mammals, separating the oral and nasal cavities. Its complex embryonic development and assembly poses unique susceptibilities to intrinsic and extrinsic disruptions. Such disruptions may cause failure of the developing palatal shelves to fuse along the midline resulting in a cleft. In other cases the palate may fuse at an arch, resulting in a vaulted oral cavity, termed high-arched palate. There are many models available for studying the pathogenesis of cleft palate but a relative paucity for high-arched palate. One condition exhibiting either cleft palate or high-arched palate is Treacher Collins syndrome, a congenital disorder characterized by numerous craniofacial anomalies. We quantitatively analyzed palatal perturbations in the Tcof1(+/-) mouse model of Treacher Collins syndrome, which phenocopies the condition in humans. We discovered that 46% of Tcof1(+/-) mutant embryos and new born pups exhibit either soft clefts or full clefts. In addition, 17% of Tcof1(+/-) mutants were found to exhibit high-arched palate, defined as two sigma above the corresponding wild-type population mean for height and angular based arch measurements. Furthermore, palatal shelf length and shelf width were decreased in all Tcof1(+/-) mutant embryos and pups compared to controls. Interestingly, these phenotypes were subsequently ameliorated through genetic inhibition of p53. The results of our study therefore provide a simple, reproducible and quantitative method for investigating models of high-arched palate.

  16. In vivo response to an implanted shape memory polyurethane foam in a porcine aneurysm model.

    Science.gov (United States)

    Rodriguez, Jennifer N; Clubb, Fred J; Wilson, Thomas S; Miller, Matthew W; Fossum, Theresa W; Hartman, Jonathan; Tuzun, Egemen; Singhal, Pooja; Maitland, Duncan J

    2014-05-01

    Cerebral aneurysms treated by traditional endovascular methods using platinum coils have a tendency to be unstable, either due to chronic inflammation, compaction of coils, or growth of the aneurysm. We propose to use alternate filling methods for the treatment of intracranial aneurysms using polyurethane-based shape memory polymer (SMP) foams. SMP polyurethane foams were surgically implanted in a porcine aneurysm model to determine biocompatibility, localized thrombogenicity, and their ability to serve as a stable filler material within an aneurysm. The degree of healing was evaluated via gross observation, histopathology, and low vacuum scanning electron microscopy imaging after 0, 30, and 90 days. Clotting was initiated within the SMP foam at time 0 (<1 h exposure to blood before euthanization), partial healing was observed at 30 days, and almost complete healing had occurred at 90 days in vivo, with minimal inflammatory response.

  17. Ex Vivo Aneurysm models mimicking real cases for the preoperative training of the clipping technique

    Directory of Open Access Journals (Sweden)

    Martin D.

    2016-06-01

    Full Text Available Training in a specialty like cerebrovascular neurosurgery becomes more and more difficult as the access to training is limited by the increasing number of neurosurgical departments and the lack of expert centers for specific pathology. This is why an increased investment in experimental training is encountered in many centers worldwide. The best models for training the clipping technique are ex Vivo on cadaveric heads aneurysm models, animal models or augmented reality models. We present a few ex Vivo models of aneurysms mimicking ACOA, ACM bifurcation and basil are tip aneurysms using a pulsed continuous perfusion system. Clipping training on aneurysm models is an invaluable tool both for the residents and for the specialists with a special interest in cerebrovascular surgery.

  18. An Interactive Tool for Automatic Predimensioning and Numerical Modeling of Arch Dams

    Directory of Open Access Journals (Sweden)

    D. J. Vicente

    2017-01-01

    Full Text Available The construction of double-curvature arch dams is an attractive solution from an economic viewpoint due to the reduced volume of concrete necessary for their construction as compared to conventional gravity dams. Due to their complex geometry, many criteria have arisen for their design. However, the most widespread methods are based on recommendations of traditional technical documents without taking into account the possibilities of computer-aided design. In this paper, an innovative software tool to design FEM models of double-curvature arch dams is presented. Several capabilities are allowed: simplified geometry creation (interesting for academic purposes, preliminary geometrical design, high-detailed model construction, and stochastic calculation performance (introducing uncertainty associated with material properties and other parameters. This paper specially focuses on geometrical issues describing the functionalities of the tool and the fundamentals of the design procedure with regard to the following aspects: topography, reference cylinder, excavation depth, crown cantilever thickness and curvature, horizontal arch curvature, excavation and concrete mass volume, and additional elements such as joints or spillways. Examples of application on two Spanish dams are presented and the results obtained analyzed.

  19. Statistical Analysis and Calculation Model of Flexibility Coefficient of Low- and Medium-Sized Arch Dam

    Directory of Open Access Journals (Sweden)

    Su Huaizhi

    2012-01-01

    Full Text Available The flexibility coefficient is popularly used to implement the macroevaluation of shape, safety, and economy for arch dam. However, the description of flexibility coefficient has not drawn a widely consensus all the time. Based on a large number of relative instance data, the relationship between influencing factor and flexibility coefficient is analyzed by means of partial least-squares regression. The partial least-squares regression equation of flexibility coefficient in certain height range between 30 m and 70 m is established. Regressive precision and equation stability are further investigated. The analytical model of statistical flexibility coefficient is provided. The flexibility coefficient criterion is determined preliminarily to evaluate the shape of low- and medium-sized arch dam. A case study is finally presented to illustrate the potential engineering application. According to the analysis result of partial least-squares regression, it is shown that there is strong relationship between flexibility coefficient and average thickness of dam, thickness-height ratio of crown cantilever, arc height ratio, and dam height, but the effect of rise-span ratio is little relatively. The considered factors in the proposed model are more comprehensive, and the applied scope is clearer than that of the traditional calculation methods. It is more suitable for the analogy analysis in engineering design and the safety evaluation for arch dam.

  20. 3D MODELLING OF PROPHYLACTIC FOOTWEAR FOR A HIGH ARCHED FOOT

    Directory of Open Access Journals (Sweden)

    COSTEA Mariana

    2016-05-01

    Full Text Available This article approaches the methodology of designing customized footwear for high arched foot. The authors propose to reconsider the classical structure of footwear bottom components for people with high arched foot and recommend incorporating custom components, with the role of compensation or adjustment. This study continues the authors’ research, starting from a foot’s 3D shape obtained by 3D scanning, the anthropometrical and biomechanical parameters, shoe lasts’ 3D modelling and continuing with 3D footwear design. Including customized orthosis can help to stop the evolution of abnormalities, diminishes sensations of pain during walking and improves performance in various physical activities carried out during the day, walking, running, and standing. The prophylactic footwear has to meet four main requirements: to protect the foot and ankle during walking and static; to ensure the normal resistance systems (bones, muscle and joint of the foot; to prevent the installation of irreversible structural changes by reducing stress on the foot; to contribute to increased performance in conducting regular physical activity. It is presented the steps of modelling an orthosis, a virtual simulation of its cutting process, followed by the integration and development of the insole, filling and sole for a customized shoe. Delcam Crispin CAD system and its applications for orthopaedics are used to design the bottom components of prophylactic footwear for a high arched foot.

  1. ARCH-M模型的经验似然估计%Empirical likelihood estimation for ARCH-M models

    Institute of Scientific and Technical Information of China (English)

    孙岩; 李元

    2012-01-01

    This paper deals with the metric of risk aversion.Test statistics are constructed by the empirical likelihood method.Under mild conditions,asymptotic x2 distributions of test statistics are obtained,based on which confidence regions for risk aversion are given.Simulations show that the empirical likelihood method behaves well.%基于ARCH-M模型研究市场总体风险厌恶的度量问题.首先应用经验似然方法构造了检验统计量,并在一定的条件下,证明了所构造的统计量的渐近分布为卡方分布,在此基础上构造了市场总体风险厌恶的置信区间.模拟结果表明,经验似然方法表现良好.

  2. Tail dependence of random variables from ARCH and heavy tailed bilinear models

    Institute of Scientific and Technical Information of China (English)

    潘家柱

    2002-01-01

    Discussed in this paper is the dependent structure in the tails of distributions of random variables from some heavy-tailed stationary nonlinear time series. One class of models discussed is the first-order autoregressive conditional heteroscedastic (ARCH) process introduced by Engle (1982). The other class is the simple first-order bilinear models driven by heavy-tailed innovations. We give some explicit formulas for the asymptotic values of conditional probabilities used for measuring the tail dependence between two random variables from these models. Our results have significant meanings in finance.

  3. GEOTECHNICAL MODELS OF THE ARCH FOUNDATIONS OF THE MASLENICA BRIDGE

    Directory of Open Access Journals (Sweden)

    Tomislav Novosel

    1998-12-01

    Full Text Available On the site of Maslenica bridge structural tectonic, geophysical and engineering geological investigations, geotechnical drilling and laboratory sample testings were performed. Maslenica anticline is characteristic for the investigated area. It is built from the limestone of Cretaceous age. The anticline has an asymmetrical form with the vergence of the axial plane towards the north. Reverse faults with recent activities are present. The recent activity was proved by the discovery of the broken stalactite with the displacement of 11 cm, whose age is 36000 years. On quite young stalactites (stalagmites in the cave on the west side, no displacements were noticed. For the next period of 500 years the maximal possible displacement of 2.0 cm is foreseen. Smaller caves with the dimensions of 1 m3, were formed on the intersections of the reverse faults and greater joints. The canyon Novsko ždrilo was formed in the fault shear zone with tectonic transport to the right. According to the range of fracture, three characteristic types of rock masses were separated by engineering geological investigations. According to »Geomechanical classification« (RMR the first type corresponds to II to III class, while the second type corresponds to IV class, and the third type corresponds to V class (mylonite. Because of the complexity of the terrain structure, original engineering geological bases of design have not enabled the direct application of the analysis of stress-strain behaviour. Because of that the simplified geotechnical models were done. They enabled the projecting of foundation in the rock mass and renewal of poor quality rock mass.

  4. The use of silicone materials to model abdominal aortic aneurysm behaviour

    OpenAIRE

    Doyle, Barry J.; Callanan, Anthony; Corbett, Timothy J.; Cloonan, Aidan J.; O'Donnell, Michael R.; Vorp, David A.; McGloughlin, Timothy M

    2008-01-01

    peer-reviewed This paper aims to identify the rupture locations of abdominal aortic aneurysms. Dow Corning Sylgard 184 was mechanically characterised. Five idealised models were then manufactured using this silicone rubber which were subsequently inflated to rupture with the images recorded using a high speed camera. Four of the five models tested ruptured at inflection points in the proximal and distal regions of the aneurysm sac, and not at regions of maximum diameter. US National Hea...

  5. ARCH Models Efficiency Evaluation in Prediction and Poultry Price Process Formation

    Directory of Open Access Journals (Sweden)

    Behzad Fakari Sardehae

    2016-09-01

    Full Text Available Introduction: Poultry is an important commodity for household consumption. In recent years, price fluctuation for this commodity has caused an uncertain condition for consumers and poultry prices over the past two years has changed a lot. This has caused many changes and uncertainty in a purchase decision. Analysis of changes and volatility modeling can be a great help to predict the poultry prices and great facilities in creating appropriate policies in future. The prices of staples such as poultry consumption basket is highly variable because much of the protein is necessary for daily energy are supplied in this way to households. So when the price of chicken which has been changed over the past two years and has always been in the press and media attention, has been selected in this study. Fluctuations in price of chicken have caused a surge in consumer expectations and contributed in volatility of chicken price. Materials and Methods: In this study ARCH models have been used for daily price of poultry of Iran’s market and this was investigated for2012-13and2013-14.BecauseARCH models can model the impact of heterogeneous variance over time in time series data then the variance of time series, which is limited in time, has no time limit. Many time series are more complex than a linear patterns, thus, non-linear models are of particular importance in Economic Sciences and Econometrics. Accordingly, Engle presented that ARCH model can model the heterogeneous variance components of the error term. That is a disturbing element and modeling can help to examine and explore the relationship between the components can be found disturbing. Basically, these models fit the data to a cluster and periodic oscillations with high volatility and low volatility associated with the period. In this study, we used several different models like ARCH, GARCH, IGARCH, and TGARCH. The distribution of the error term of the model also followt-student distribution

  6. A Mathematical Model of Intracranial Saccular Aneurysms: Evidence of Hemodynamic Instability

    Science.gov (United States)

    Calvisi, Michael; Davis, Stephen; Miksis, Michael

    2010-11-01

    Intracranial saccular aneurysms tend to form at the apex of arterial bifurcations and often assume a nominally spherical shape. In certain cases, the aneurysm growth can become unstable and lead to rupture. While the mechanisms of instability are not well understood, hemodynamics almost certainly play an important role. In this talk, a mathematical model of a saccular aneurysm is presented that describes the shape deformations of an initially spherical membrane interacting with a viscous fluid in the interior. The governing equations are derived from the equations of a thin shell supplemented with a constitutive model that is representative of aneurysmal tissue. Among the key findings are that two families of free vibration modes exist and, for certain values of the membrane properties, one family of nonspherical, axisymmetric modes is unstable to small perturbations. In addition, the presence of a vortical interior flow of sufficient strength can excite resonance of the membrane -- an unstable phenomenon that might cause eventual rupture.

  7. Experimental Model of Saccular Abdominal Aortic Aneurysm in Swines with Pericardium Sac

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    Maurício de Amorim Aquino

    2016-02-01

    Full Text Available Abstract Objective: To consider modifications in an experimental model of saccular aortic aneurysm, aiming at better reproducibility, to be used in the development of vascular prostheses. Methods: Experimental study in two phases, developed in the Center of Experimental Surgery and Bioterium (CCEB of the University of Health Sciences of Alagoas (UNCISAL, with 11 hybrid swine, female, mean weight of 20 ± 5 kg, according to modifications in the Perini technique was performed. In the first phase, the aneurysm was confectioned with bovine pericardial patch. In the second phase, fifteen days later, the patency of the aneurysms was confirmed by Doppler ultrasonography. The described variables were aortic and aneurysm sac patency, incidence of rupture, morbidity and mortality. The statistical analysis program used was STATA v.8. Results: All animals survived to the procedures. Surgical mean time was 73 minutes. Aneurysm rupture, proximal or distal aortic thrombosis, visceral or legs ischemia weren't observed. Parietal thrombus formation was observed in all of the aneurysms, two of which (18%; IC 95% = 3.98 - 48.84 were occluded and nine (82%; IC 95% = 51.15 - 96.01 were patent. Conclusion: In this series, the modifications carried out in the technique related to the surgical approach, race, anesthesia, and imaging exams reproduced the experimental model, reducing its costs, without hindering the analysis of the variables. The satisfactory patency ratio allows the method to be used in experimental models for the development of vascular prostheses.

  8. Estimating the Volatility of Cocoa Price Return with ARCH and GARCH Models

    Directory of Open Access Journals (Sweden)

    Lya Aklimawati

    2013-08-01

    Full Text Available Dynamics of market changing as a result of market liberalization have an impact on agricultural commodities price fluctuation. High volatility on cocoa price movement reflect its price and market risk. Because of price and market uncertainty, the market players face some difficulties to make a decision in determining business development. This research was conducted to 1 understand the characteristics of cocoa price movement in cocoa futures trading, and 2analyze cocoa price volatility using ARCH and GARCH type model. Research was carried out by direct observation on the pattern of cocoa price movement in the futures trading and volatility analysis based on secondary data. The data was derived from Intercontinental Exchange ( ICE Futures U.S. Reports. The analysis result showed that GARCH is the best model to predict the value of average cocoa price return volatility, because it meets criteria of three diagnostic checking, which are ARCH-LM test, residual autocorrelation test and residual normality test. Based on the ARCH-LM test, GARCH (1,1did not have heteroscedasticity, because p-value  2 (0.640139and F-statistic (0.640449 were greater than 0.05. Results of residual autocorrelation test indicated that residual value of GARCH (1,1 was random, because the statistic value of Ljung-Box (LBon the 36 th lag is smaller than the statistic value of  2. Whereas, residual normality test concluded the residual of GARCH (1,1 were normally distributed, because AR (29, MA (29, RESID (-1^2, and GARCH (-1 were significant at 5% significance level. Increasing volatility value indicate high potential risk. Price risk can be reduced by managing financial instrument in futures trading such as forward and futures contract, and hedging. The research result also give an insight to the market player for decision making and determining time of hedging. Key words: Volatility, price, cocoa, GARCH, risk, futures trading

  9. Experimental unsteady flow study in a patient-specific abdominal aortic aneurysm model

    Science.gov (United States)

    Stamatopoulos, Ch.; Mathioulakis, D. S.; Papaharilaou, Y.; Katsamouris, A.

    2011-06-01

    The velocity field in a patient-specific abdominal aneurysm model including the aorto-iliac bifurcation was measured by 2D PIV. Phase-averaged velocities obtained in 14 planes reveal details of the flow evolution during a cycle. The aneurysm expanding asymmetrically toward the anterior side of the aorta causes the generation of a vortex at its entrance, covering the entire aneurysm bulge progressively before flow peak. The fluid entering the aneurysm impinges on the left side of its distal end, following the axis of the upstream aorta segment, causing an increased flow rate in the left (compared to the right) common iliac artery. High shear stresses appear at the aneurysm inlet and outlet as well as along the posterior wall, varying proportionally to the flow rate. At the same regions, elevated flow disturbances are observed, being intensified at flow peak and during the deceleration phase. Low shear stresses are present in the recirculation region, being two orders of magnitude smaller than the previous ones. At flow peak and during the deceleration phase, a clockwise swirling motion (viewed from the inlet) is present in the aneurysm due to the out of plane curvature of the aorta.

  10. Aneurisma do ducto arterioso associado a interrupção do arco aórtico Aneurysm of the arterial duct associated to aortic arch interruption

    Directory of Open Access Journals (Sweden)

    Paulo Zielinsky

    1998-07-01

    Full Text Available É relatado um caso de aneurisma de ducto arterioso, com diagnóstico pré-natal, o que é muito raro, numa gestante com 33 semanas, onde o feto apresentou uma dilatação aneurismática do canal arterial, com calibre uniformemente aumentado, inserindo-se na aorta descendente, associado à interrupção do arco aórtico. A criança nasceu de parto cesáreo e manteve-se estável com o uso de prostaglandina até o 9º dia de vida, quando foi levada à cirurgia, tendo falecido durante o procedimento por falência biventricular. Este é o primeiro relato da associação desta anomalia com outra malformação cardiovascular intra-uterina, mostrando que este achado nem sempre é associado a uma evolução benigna.Aneurysm of the arterial duct is an infrequent finding, which is very rarely detected prenatally. A case of antenatal diagnosis in a pregnant patient (33 weeks is reported. The fetus presented an aneurysmatic dilation of the arterial duct with uniformly enlarged diameter, inserting into the descending aorta, which was interrupted. The neonate was born by cesarean section and was kept on postaglandins till the 9th day of life, when he was sent to surgery. During the surgical procedure, the baby died as a result of biventricular failure. This is the first report of prenatal association of aneurysm of the ducts anteriosus with other cardiovascular malformations and emphasizes that this finding does not always have a benign course.

  11. Modeling variations in the cedi/dollar exchange rate in Ghana: an autoregressive conditional heteroscedastic (ARCH) models.

    Science.gov (United States)

    Techie Quaicoe, Michael; Twenefour, Frank B K; Baah, Emmanuel M; Nortey, Ezekiel N N

    2015-01-01

    This research article aimed at modeling the variations in the dollar/cedi exchange rate. It examines the applicability of a range of ARCH/GARCH specifications for modeling volatility of the series. The variants considered include the ARMA, GARCH, IGARCH, EGARCH and M-GARCH specifications. The results show that the series was non stationary which resulted from the presence of a unit root in it. The ARMA (1, 1) was found to be the most suitable model for the conditional mean. From the Box-Ljung test statistics x-squared of 1476.338 with p value 0.00217 for squared returns and 16.918 with 0.0153 p values for squared residuals, the null hypothesis of no ARCH effect was rejected at 5% significance level indicating the presence of an ARCH effect in the series. ARMA (1, 1) + GARCH (1, 1) which has all parameters significant was found to be the most suitable model for the conditional mean with conditional variance, thus showing adequacy in describing the conditional mean with variance of the return series at 5% significant level. A 24 months forecast for the mean actual exchange rates and mean returns from January, 2013 to December, 2014 made also showed that the fitted model is appropriate for the data and a depreciating trend of the cedi against the dollar for forecasted period respectively.

  12. Self-Expandable Stent for Repairing Coarctation of the Left-Circumferential Aortic Arch with Right-sided Descending Aorta and Aberrant Right Subclavian Artery with Kommerell's Aneurysm.

    Science.gov (United States)

    Khajali, Zahra; Sanati, Hamid Reza; Pouraliakbar, Hamidreza; Mohebbi, Bahram; Aeinfar, Kamran; Zolfaghari, Reza

    2017-01-01

    Endovascular treatment offers a great advantage in the management of main arteries stenoses. However, simultaneous presence of a group of anomalies may complicate the situation. Here we present a case of 21-year-old man with aortic coarctation. Radiographic imaging and angiography demonstrated aortic coarctation of the left-circumferential aortic arch, right-sided descending aorta, and Kommerell's diverticulum at the origin of right subclavian artery. These anomalies have rarely been reported to concurrently exist in the same case and the treatment is challenging. Percutaneous treatment for repair of aortic coarctation was successfully performed with deployment of self-expanding nitinol stents. Follow-up demonstrated the correction of blood pressure and improvement of the symptoms. It appears that deployment of self-expandable nitinol stents present a viable option for the management of coarcted aorta in patients having all or some of these anomalies together.

  13. Effects of Hydroxyapatite on Bone Graft Resorption in an Experimental Model of Maxillary Alveolar Arch Defects

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    Ozgur Pilanci

    2013-06-01

    Full Text Available Most commonly used treatments use autologous bone grafts to address bony defects in patients with cleft palate. Major disadvantages of autogenous bone grafts include donor site morbidity and resorption. Suggestions to overcome such problems include biomaterials that can be used alone or in combination with bone. We examined the effect of hydroxyapatite cement on bone graft resorption in a rabbit maxillary alveolar defect model. We divided 16 young adult albino New Zealand rabbits into two groups. A defect 1 cm wide was created in each rabbit's maxillary arch. In Group 1, the removed bone was disrupted, and the pieces were replaced in the defect. In the other group, the pieces were replaced after mixing (1:1 with hydroxyapatite cement. Quantitative computed tomographic evaluation of these grafts was performed in axial and coronal planes for each rabbit at 2 and 12 weeks. In axial images at 12 weeks, the group without cement showed mean bone resorption of 15%. In the cement group, a mean volumetric increase of 68% was seen. No resorption occurred when bone grafts were mixed with hydroxyapatite cement. [Arch Clin Exp Surg 2013; 2(3.000: 170-175

  14. Novel technique for arch and visceral artery debranching using ascending aortic inflow.

    Science.gov (United States)

    Mussa, Firas F; Walkes, Jon-Cecil; Lumsden, Alan B; Reardon, Michael J

    2008-01-01

    Aortic arch aneurysms extending proximally to the left subclavian artery have traditionally been approached through a median sternotomy and a staged elephant trunk procedure requiring a left thoracotomy or thoracoabdominal incision. We describe a novel technique for repair of such aneurysms in a single-stage, hybrid approach using bypass grafts arising from the ascending aorta to all arch and upper abdominal visceral arteries followed by endovascular exclusion of the aortic aneurysm.

  15. The analysis of volatility of gold coin price fluctuations in Iran using ARCH & VAR models

    Directory of Open Access Journals (Sweden)

    Younos Vakilolroaya

    2014-03-01

    Full Text Available The aim of this study is to investigate the changes in gold price and modeling of its return volatility and conditional variance model. The study gathers daily prices of gold coins as the dependent variable and the price of gold in world market, the price of oil in OPEC, exchange rate USD to IRR and index of Tehran Stock Exchange from March 2007 to July 2013 and using ARCH family models and VAR methods, the study analysis the data. The study first examines whether the data are stationary or not and then it reviews the household stability, Arch and Garch models. The proposed study investigates the causality among variables, selects different factors, which could be blamed of uncertainty in the coin return. The results indicate that the effect of sudden changes of standard deviation and after a 14-day period disappears and gold price goes back to its initial position. In addition, in this study we observe the so-called leverage effect in Iran’s Gold coin market, which means the good news leads to more volatility in futures market than bad news in an equal size. Finally, the result of analysis of variance implies that in the short-term, a large percentage change in uncertainty of the coin return is due to changes in the same factors and volatility of stock returns in the medium term, global gold output, oil price and exchange rate fluctuation to some extent will show the impact. In the long run, the effects of parameters are more evident.

  16. Investigation of magnetic nanoparticle targeting in a simplified model of small vessel aneurysm

    Science.gov (United States)

    Mirzababaei, S. N.; Gorji, Tahereh B.; Baou, M.; Gorji-Bandpy, M.; Fatouraee, Nasser

    2017-03-01

    An in simulacra study was conducted to investigate the capture efficiency (CE) of magnetic nanoparticles (MNPs) in aneurysm model, under the effect of a bipolar permanent magnetic system positioned at the vicinity of the model vessel. The bipolar magnetic system with an active space of 9 cm was designed by FEMM software. The MNPs were magnetite nanoparticles synthesized by the hydrothermal method which were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope and magnetometer measurements. Ferrofluid velocity, magnetic field strength, and aneurysm volume all proved to be important parameters which affect the capturing of MNPs. Overall, the results of this in simulacra study confirmed the effectiveness of magnetic targeting for possible aneurysm embolization.

  17. Induction of continuous expanding infrarenal aortic aneurysms in a large porcine animal model

    DEFF Research Database (Denmark)

    Kloster, Brian Ozeraitis; Lund, Lars; Lindholt, Jes S.

    2015-01-01

    BackgroundA large animal model with a continuous expanding infrarenal aortic aneurysm gives access to a more realistic AAA model with anatomy and physiology similar to humans, and thus allows for new experimental research in the natural history and treatment options of the disease. Methods10 pigs...

  18. Induction of continuous expanding infrarenal aortic aneurysms in a large porcine animal model

    DEFF Research Database (Denmark)

    Kloster, Brian Ozeraitis; Lund, Lars; Lindholt, Jes S.

    2015-01-01

    BACKGROUND: A large animal model with a continuous expanding infrarenal aortic aneurysm gives access to a more realistic AAA model with anatomy and physiology similar to humans, and thus allows for new experimental research in the natural history and treatment options of the disease. METHODS: 10...

  19. [Rapid 3-Dimensional Models of Cerebral Aneurysm for Emergency Surgical Clipping].

    Science.gov (United States)

    Konno, Takehiko; Mashiko, Toshihiro; Oguma, Hirofumi; Kaneko, Naoki; Otani, Keisuke; Watanabe, Eiju

    2016-08-01

    We developed a method for manufacturing solid models of cerebral aneurysms, with a shorter printing time than that involved in conventional methods, using a compact 3D printer with acrylonitrile-butadiene-styrene(ABS)resin. We further investigated the application and utility of this printing system in emergency clipping surgery. A total of 16 patients diagnosed with acute subarachnoid hemorrhage resulting from cerebral aneurysm rupture were enrolled in the present study. Emergency clipping was performed on the day of hospitalization. Digital Imaging and Communication in Medicine(DICOM)data obtained from computed tomography angiography(CTA)scans were edited and converted to stereolithography(STL)file formats, followed by the production of 3D models of the cerebral aneurysm by using the 3D printer. The mean time from hospitalization to the commencement of surgery was 242 min, whereas the mean time required for manufacturing the 3D model was 67 min. The average cost of each 3D model was 194 Japanese Yen. The time required for manufacturing the 3D models shortened to approximately 1 hour with increasing experience of producing 3D models. Favorable impressions for the use of the 3D models in clipping were reported by almost all neurosurgeons included in this study. Although 3D printing is often considered to involve huge costs and long manufacturing time, the method used in the present study requires shorter time and lower costs than conventional methods for manufacturing 3D cerebral aneurysm models, thus making it suitable for use in emergency clipping.

  20. Glossary to ARCH (GARCH)

    DEFF Research Database (Denmark)

    Bollerslev, Tim

    The literature on modeling and forecasting time-varying volatility is ripe with acronyms and abbreviations used to describe the many different parametric models that have been put forth since the original linear ARCH model introduced in the seminal Nobel Prize winning paper by Engle (1982......).  The present paper provides an easy-to-use encyclopedic reference guide to this long list of ARCH acronyms.  In addition to the acronyms associated with specific parametric models, I have also included descriptions of various abbreviations associated with more general statistical procedures and ideas...

  1. Proactive monitoring and adaptive management of social carrying capacity in Arches National Park: an application of computer simulation modeling.

    Science.gov (United States)

    Lawson, Steven R; Manning, Robert E; Valliere, William A; Wang, Benjamin

    2003-07-01

    Public visits to parks and protected areas continue to increase and may threaten the integrity of natural and cultural resources and the quality of the visitor experience. Scientists and managers have adopted the concept of carrying capacity to address the impacts of visitor use. In the context of outdoor recreation, the social component of carrying capacity refers to the level of visitor use that can be accommodated in parks and protected areas without diminishing the quality of the visitor experience to an unacceptable degree. This study expands and illustrates the use of computer simulation modeling as a tool for proactive monitoring and adaptive management of social carrying capacity at Arches National Park. A travel simulation model of daily visitor use throughout the Park's road and trail network and at selected attraction sites was developed, and simulations were conducted to estimate a daily social carrying capacity for Delicate Arch, an attraction site in Arches National Park, and for the Park as a whole. Further, a series of simulations were conducted to estimate the effect of a mandatory shuttle bus system on daily social carrying capacity of Delicate Arch to illustrate how computer simulation modeling can be used as a tool to facilitate adaptive management of social carrying capacity.

  2. Blood flow in intracranial aneurysms treated with Pipeline embolization devices: computational simulation and verification with Doppler ultrasonography on phantom models

    Directory of Open Access Journals (Sweden)

    Anderson Chun On Tsang

    2015-04-01

    Full Text Available Purpose: The aim of this study was to validate a computational fluid dynamics (CFD simulation of flow-diverter treatment through Doppler ultrasonography measurements in patient-specific models of intracranial bifurcation and side-wall aneurysms. Methods: Computational and physical models of patient-specific bifurcation and sidewall aneurysms were constructed from computed tomography angiography with use of stereolithography, a three-dimensional printing technology. Flow dynamics parameters before and after flow-diverter treatment were measured with pulse-wave and color Doppler ultrasonography, and then compared with CFD simulations. Results: CFD simulations showed drastic flow reduction after flow-diverter treatment in both aneurysms. The mean volume flow rate decreased by 90% and 85% for the bifurcation aneurysm and the side-wall aneurysm, respectively. Velocity contour plots from computer simulations before and after flow diversion closely resembled the patterns obtained by color Doppler ultrasonography. Conclusion: The CFD estimation of flow reduction in aneurysms treated with a flow-diverting stent was verified by Doppler ultrasonography in patient-specific phantom models of bifurcation and side-wall aneurysms. The combination of CFD and ultrasonography may constitute a feasible and reliable technique in studying the treatment of intracranial aneurysms with flow-diverting stents.

  3. Flow modification in canine intracranial aneurysm model by an asymmetric stent: studies using digital subtraction angiography (DSA) and image-based computational fluid dynamics (CFD) analyses

    Science.gov (United States)

    Hoi, Yiemeng; Ionita, Ciprian N.; Tranquebar, Rekha V.; Hoffmann, Kenneth R.; Woodward, Scott H.; Taulbee, Dale B.; Meng, Hui; Rudin, Stephen

    2006-03-01

    An asymmetric stent with low porosity patch across the intracranial aneurysm neck and high porosity elsewhere is designed to modify the flow to result in thrombogenesis and occlusion of the aneurysm and yet to reduce the possibility of also occluding adjacent perforator vessels. The purposes of this study are to evaluate the flow field induced by an asymmetric stent using both numerical and digital subtraction angiography (DSA) methods and to quantify the flow dynamics of an asymmetric stent in an in vivo aneurysm model. We created a vein-pouch aneurysm model on the canine carotid artery. An asymmetric stent was implanted at the aneurysm, with 25% porosity across the aneurysm neck and 80% porosity elsewhere. The aneurysm geometry, before and after stent implantation, was acquired using cone beam CT and reconstructed for computational fluid dynamics (CFD) analysis. Both steady-state and pulsatile flow conditions using the measured waveforms from the aneurysm model were studied. To reduce computational costs, we modeled the asymmetric stent effect by specifying a pressure drop over the layer across the aneurysm orifice where the low porosity patch was located. From the CFD results, we found the asymmetric stent reduced the inflow into the aneurysm by 51%, and appeared to create a stasis-like environment which favors thrombus formation. The DSA sequences also showed substantial flow reduction into the aneurysm. Asymmetric stents may be a viable image guided intervention for treating intracranial aneurysms with desired flow modification features.

  4. Establishment of a chronic left ventricular aneurysm model in rabbit

    Institute of Scientific and Technical Information of China (English)

    Cang-Song XIAO; Chang-Qing GAO; Li-Bing LI; Yao WANG; Tao ZHAO; Wei-Hua YE; Chong-Lei REN; Zhi-Yong LIU; Yang WU

    2014-01-01

    Objectives To establish a cost-effective and reproducible procedure for induction of chronic left ventricular aneurysm (LVA) in rabbits. Methods Acute myocardial infarction (AMI) was induced in 35 rabbits via concomitant ligation of the left anterior descending (LAD) coronary artery and the circumflex (Cx) branch at the middle portion. Development of AMI was co n-firmed by ST segment elevation and akinesis of the occluded area. Echocardiography, pathological evaluation, and agar i n-tra-chamber casting were utilized to validate the formation of LVA four weeks after the surgery. Left ventricular end systolic pressure (LVESP) and diastolic pressure (LVEDP) were measured before, immediately after and four weeks after ligation. D i-mensions of the ventricular chamber, thickness of the interventricular septum (IVS) and the left ventricular posterior wall (LVPW) left ventricular end diastolic volume (LVEDV) and systolic volume (LVESV), and ejection fraction (EF) were recorded by echo-cardiography. Results Thirty one (88.6%) rabbits survived myocardial infarction and 26 of them developed aneurysm (83.9%). The mean area of aneurysm was 33.4% ± 2.4% of the left ventricle. LVEF markedly decreased after LVA formation, whereas LVEDV, LVESV and the thickness of IVS as well as the dimension of ventricular chamber from apex to mitral valve annulus significantly increased. LVESP immediately dropped after ligation and recovered to a small extent after LVA formation. LVEDP progressively increased after ligation till LVA formation. Areas in the left ventricle (LV) that underwent fibrosis included the apex, anterior wall and lateral wall but not IVS. Agar intra-chamber cast showed that the bulging of LV wall was prominent in the area of aneurysm. Conclusions Ligation of LAD and Cx at the middle portion could induce develo pment of LVA at a mean area ratio of 33.4%±2.4%which involves the apex, anterior wall and lateral wall of the LV.

  5. PIV-measured versus CFD-predicted flow dynamics in anatomically realistic cerebral aneurysm models.

    Science.gov (United States)

    Ford, Matthew D; Nikolov, Hristo N; Milner, Jaques S; Lownie, Stephen P; Demont, Edwin M; Kalata, Wojciech; Loth, Francis; Holdsworth, David W; Steinman, David A

    2008-04-01

    Computational fluid dynamics (CFD) modeling of nominally patient-specific cerebral aneurysms is increasingly being used as a research tool to further understand the development, prognosis, and treatment of brain aneurysms. We have previously developed virtual angiography to indirectly validate CFD-predicted gross flow dynamics against the routinely acquired digital subtraction angiograms. Toward a more direct validation, here we compare detailed, CFD-predicted velocity fields against those measured using particle imaging velocimetry (PIV). Two anatomically realistic flow-through phantoms, one a giant internal carotid artery (ICA) aneurysm and the other a basilar artery (BA) tip aneurysm, were constructed of a clear silicone elastomer. The phantoms were placed within a computer-controlled flow loop, programed with representative flow rate waveforms. PIV images were collected on several anterior-posterior (AP) and lateral (LAT) planes. CFD simulations were then carried out using a well-validated, in-house solver, based on micro-CT reconstructions of the geometries of the flow-through phantoms and inlet/outlet boundary conditions derived from flow rates measured during the PIV experiments. PIV and CFD results from the central AP plane of the ICA aneurysm showed a large stable vortex throughout the cardiac cycle. Complex vortex dynamics, captured by PIV and CFD, persisted throughout the cardiac cycle on the central LAT plane. Velocity vector fields showed good overall agreement. For the BA, aneurysm agreement was more compelling, with both PIV and CFD similarly resolving the dynamics of counter-rotating vortices on both AP and LAT planes. Despite the imposition of periodic flow boundary conditions for the CFD simulations, cycle-to-cycle fluctuations were evident in the BA aneurysm simulations, which agreed well, in terms of both amplitudes and spatial distributions, with cycle-to-cycle fluctuations measured by PIV in the same geometry. The overall good agreement

  6. A new flow-diverter(the FloWise): In vivo evaluation in an elastase-induced rabbit aneurysm model

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byung Moon; Kim, Dong Joon; Kim, Dong Ik [Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2016-02-15

    We aimed to evaluate the efficacy and safety of a newly developed, partially retrievable flow-diverter (the FloWise) in an elastase-induced rabbit aneurysm model. We developed a partially retrievable flow diverter composed of 48 strands of Nitinol and platinum wire. The FloWise is compatible with any microcatheter of 0.027-inch inner diameter, and is retrievable up to 70% deployment. The efficacy and safety of the FloWise were evaluated in the elastase-induced rabbit aneurysm model. The rate of technical success (full coverage of aneurysm neck) and assessment of aneurysm occlusion and stent patency was conducted by angiograms and histologic examinations at the 1-month, 3-month, and 6-month follow-up. The patency of small arterial branches (intercostal or lumbar arteries) covered by the FloWise were also assessed in the 5 subjects. We attempted FloWise insertion in a total of 32 aneurysm models. FloWise placement was successful in 31 subjects (96.9%). Two stents (6.2%) were occluded at the 3-month follow-up, but there was no evidence of in-stent stenosis in other subjects. All stented aneurysms showed progressive occlusion: grade I (complete aneurysm occlusion) in 44.4% and grade II (aneurysm occlusion > 90%) in 55.6% at 1 month; grade I in 90% and II in 10% at 3 months; and grade I in 90% and II in 10% at 6 months. All small arterial branches covered by the FloWise remained patent. A newly developed, partially retrievable flow-diverter seems to be a safe and effective tool of aneurysm occlusion, as evaluated in the rabbit aneurysm model.

  7. Fluid structure interaction simulation in three-layered aortic aneurysm model under pulsatile flow: comparison of wrapping and stenting.

    Science.gov (United States)

    Gao, Feng; Ueda, Hiroshi; Gang, Li; Okada, Hiroshi

    2013-04-26

    One treatment method for aortic aneurysm is the invasive insertion of a stent into the aneurysm. Another method is wrapping the aneurysm using newly developed expanded polytetrafluoroethylene (PTFE) material. A virtual stented aneurysm model and a wrapped aneurysm model were created to study the flow and wall dynamics by means of fluid-structure interaction analyses. The flow velocity and pressure distribution as well as the deformation and wall stress were investigated. Stenting significantly changed the blood flow pattern and the vortexes in the aneurysm. Wrapping increased the thickness of the aneurysm wall and increased the strength of the vessel wall. The maximum von Mises stress in the stented model was found to be 220,494 Pa and 228,218 Pa at the time of peak flow and peak pressure, respectively. This was reduced by 37.8% and 36.7% to 137,200 and 144,354 Pa, respectively, in the wrapped model. Our results provide information that may improve the understanding of the biomechanics of stenting and wrapping.

  8. Deformation Monitoring of Geomechanical Model Test and Its Application in Overall Stability Analysis of a High Arch Dam

    Directory of Open Access Journals (Sweden)

    Baoquan Yang

    2015-01-01

    Full Text Available Geomechanical model testing is an important method for studying the overall stability of high arch dams. The main task of a geomechanical model test is deformation monitoring. Currently, many types of deformation instruments are used for deformation monitoring of dam models, which provide valuable information on the deformation characteristics of the prototype dams. However, further investigation is required for assessing the overall stability of high arch dams through analyzing deformation monitoring data. First, a relationship for assessing the stability of dams is established based on the comprehensive model test method. Second, a stability evaluation system is presented based on the deformation monitoring data, together with the relationships between the deformation and overloading coefficient. Finally, the comprehensive model test method is applied to study the overall stability of the Jinping-I high arch dam. A three-dimensional destructive test of the geomechanical model dam is conducted under reinforced foundation conditions. The deformation characteristics and failure mechanisms of the dam abutments and foundation were investigated. The test results indicate that the stability safety factors of the dam abutments and foundation range from 5.2 to 6.0. These research results provide an important scientific insight into the design, construction, and operation stages of this project.

  9. Effect of Low-Pressurized Perfusion with Different Concentration of Elastase on the Aneurysm Formation Rate in the Abdominal Aortic Aneurysm Model in Rabbits.

    Science.gov (United States)

    Nie, Maoxiao; Yan, Yunfeng; Li, Xinhe; Feng, Tingting; Zhao, Xin; Zhang, Mingduo; Zhao, Quanming

    2016-01-01

    Establishing an animal model of abdominal aortic aneurysm (AAA) is the key to study the pathogenesis and the pathophysiological features of AAAs. We investigated the effects of low-pressurized perfusion with different concentrations of elastase on aneurysm formation rate in the AAA model. Fifty male New Zealand white rabbits were randomly divided into A, B, C, D, and E groups. 10 μL of normal saline was perfused into the abdominal aorta in group A and 1 U/mL, 10 U/mL, 100 U/mL, or 200 U/mL of elastase was, respectively, perfused for the other four groups. All the animals were perfused for 7 min. Doppler ultrasound examinations of the abdominal aorta were performed before surgery and on day 14 after surgery. The rabbits were sacrificed and the perfused segment of the abdominal aorta was observed visually and after staining. The aneurysm formation rate of group A, group B, group C, group D, and group E was, respectively, 0%, 0%, 33.3%, 102.5-146.8%, and 241.5-255.2%. The survival rate of five groups was 90%, 90%, 90%, 90%, and 40%, respectively. So, we concluded that low-pressurized perfusion with 100 U/mL of elastase can effectively establish AAAs in rabbits with a high aneurysm formation rate.

  10. Hemodynamic flow modeling through an abdominal aorta aneurysm using data mining tools.

    Science.gov (United States)

    Filipovic, Nenad; Ivanovic, Milos; Krstajic, Damjan; Kojic, Milos

    2011-03-01

    Geometrical changes of blood vessels, called aneurysm, occur often in humans with possible catastrophic outcome. Then, the blood flow is enormously affected, as well as the blood hemodynamic interaction forces acting on the arterial wall. These forces are the cause of the wall rupture. A mechanical quantity characteristic for the blood-wall interaction is the wall shear stress, which also has direct physiological effects on the endothelial cell behavior. Therefore, it is very important to have an insight into the blood flow and shear stress distribution when an aneurysm is developed in order to help correlating the mechanical conditions with the pathogenesis of pathological changes on the blood vessels. This insight can further help in improving the prevention of cardiovascular diseases evolution. Computational fluid dynamics (CFD) has been used in general as a tool to generate results for the mechanical conditions within blood vessels with and without aneurysms. However, aneurysms are very patient specific and reliable results from CFD analyses can be obtained by a cumbersome and time-consuming process of the computational model generation followed by huge computations. In order to make the CFD analyses efficient and suitable for future everyday clinical practice, we have here employed data mining (DM) techniques. The focus was to combine the CFD and DM methods for the estimation of the wall shear stresses in an abdominal aorta aneurysm (AAA) underprescribed geometrical changes. Additionally, computing on the grid infrastructure was performed to improve efficiency, since thousands of CFD runs were needed for creating machine learning data. We used several DM techniques and found that our DM models provide good prediction of the shear stress at the AAA in comparison with full CFD model results on real patient data.

  11. Spectral algorithm for non-destructive damage localisation: Application to an ancient masonry arch model

    Science.gov (United States)

    Masciotta, Maria-Giovanna; Ramos, Luís F.; Lourenço, Paulo B.; Vasta, Marcello

    2017-02-01

    Structural monitoring and vibration-based damage identification methods are fundamental tools for condition assessment and early-stage damage identification, especially when dealing with the conservation of historical constructions and the maintenance of strategic civil structures. However, although the substantial advances in the field, several issues must still be addressed to broaden the application range of such tools and to assert their reliability. This study deals with the experimental validation of a novel method for non-destructive damage identification purposes. This method is based on the use of spectral output signals and has been recently validated by the authors through a numerical simulation. After a brief insight into the basic principles of the proposed approach, the spectral-based technique is applied to identify the experimental damage induced on a masonry arch through statically increasing loading. Once the direct and cross spectral density functions of the nodal response processes are estimated, the system's output power spectrum matrix is built and decomposed in eigenvalues and eigenvectors. The present study points out how the extracted spectral eigenparameters contribute to the damage analysis allowing to detect the occurrence of damage and to locate the target points where the cracks appear during the experimental tests. The sensitivity of the spectral formulation to the level of noise in the modal data is investigated and discussed. As a final evaluation criterion, the results from the spectrum-driven method are compared with the ones obtained from existing non-model based damage identification methods.

  12. Fluid-structure Interaction Modeling of Aneurysmal Conditions with High and Normal Blood Pressures

    Science.gov (United States)

    Torii, Ryo; Oshima, Marie; Kobayashi, Toshio; Takagi, Kiyoshi; Tezduyar, Tayfun E.

    2006-09-01

    Hemodynamic factors like the wall shear stress play an important role in cardiovascular diseases. To investigate the influence of hemodynamic factors in blood vessels, the authors have developed a numerical fluid-structure interaction (FSI) analysis technique. The objective is to use numerical simulation as an effective tool to predict phenomena in a living human body. We applied the technique to a patient-specific arterial model, and with that we showed the effect of wall deformation on the WSS distribution. In this paper, we compute the interaction between the blood flow and the arterial wall for a patient-specific cerebral aneurysm with various hemodynamic conditions, such as hypertension. We particularly focus on the effects of hypertensive blood pressure on the interaction and the WSS, because hypertension is reported to be a risk factor in rupture of aneurysms. We also aim to show the possibility of FSI computations with hemodynamic conditions representing those risk factors in cardiovascular disease. The simulations show that the transient behavior of the interaction under hypertensive blood pressure is significantly different from the interaction under normal blood pressure. The transient behavior of the blood-flow velocity, and the resulting WSS and the mechanical stress in the aneurysmal wall, are significantly affected by hypertension. The results imply that hypertension affects the growth of an aneurysm and the damage in arterial tissues.

  13. Measurement with microscopic MRI and simulation of flow in different aneurysm models

    Energy Technology Data Exchange (ETDEWEB)

    Edelhoff, Daniel, E-mail: daniel.edelhoff@tu-dortmund.de; Frank, Frauke; Heil, Marvin; Suter, Dieter [Experimental Physics III, TU Dortmund University, Otto-Hahn-Street 4, Dortmund 44227 (Germany); Walczak, Lars; Weichert, Frank [Computer Science VII, TU Dortmund University, Otto-Hahn-Street 16, Dortmund 44227 (Germany); Schmitz, Inge [Institute for Pathology, Ruhr Universität Bochum, Bürkle-de-la-Camp-Platz 1, Bochum 44789 (Germany)

    2015-10-15

    Purpose: The impact and the development of aneurysms depend to a significant degree on the exchange of liquid between the regular vessel and the pathological extension. A better understanding of this process will lead to improved prediction capabilities. The aim of the current study was to investigate fluid-exchange in aneurysm models of different complexities by combining microscopic magnetic resonance measurements with numerical simulations. In order to evaluate the accuracy and applicability of these methods, the fluid-exchange process between the unaltered vessel lumen and the aneurysm phantoms was analyzed quantitatively using high spatial resolution. Methods: Magnetic resonance flow imaging was used to visualize fluid-exchange in two different models produced with a 3D printer. One model of an aneurysm was based on histological findings. The flow distribution in the different models was measured on a microscopic scale using time of flight magnetic resonance imaging. The whole experiment was simulated using fast graphics processing unit-based numerical simulations. The obtained simulation results were compared qualitatively and quantitatively with the magnetic resonance imaging measurements, taking into account flow and spin–lattice relaxation. Results: The results of both presented methods compared well for the used aneurysm models and the chosen flow distributions. The results from the fluid-exchange analysis showed comparable characteristics concerning measurement and simulation. Similar symmetry behavior was observed. Based on these results, the amount of fluid-exchange was calculated. Depending on the geometry of the models, 7% to 45% of the liquid was exchanged per second. Conclusions: The result of the numerical simulations coincides well with the experimentally determined velocity field. The rate of fluid-exchange between vessel and aneurysm was well-predicted. Hence, the results obtained by simulation could be validated by the experiment. The

  14. Mathematical modeling and numerical analysis of thermal distribution in arch dams considering solar radiation effect.

    Science.gov (United States)

    Mirzabozorg, H; Hariri-Ardebili, M A; Shirkhan, M; Seyed-Kolbadi, S M

    2014-01-01

    The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams.

  15. Implantation of 3D-Printed Patient-Specific Aneurysm Models into Cadaveric Specimens: A New Training Paradigm to Allow for Improvements in Cerebrovascular Surgery and Research

    Directory of Open Access Journals (Sweden)

    Arnau Benet

    2015-01-01

    Full Text Available Aim. To evaluate the feasibility of implanting 3D-printed brain aneurysm model in human cadavers and to assess their utility in neurosurgical research, complex case management/planning, and operative training. Methods. Two 3D-printed aneurysm models, basilar apex and middle cerebral artery, were generated and implanted in four cadaveric specimens. The aneurysms were implanted at the same anatomical region as the modeled patient. Pterional and orbitozygomatic approaches were done on each specimen. The aneurysm implant, manipulation capabilities, and surgical clipping were evaluated. Results. The 3D aneurysm models were successfully implanted to the cadaveric specimens’ arterial circulation in all cases. The features of the neck in terms of flexibility and its relationship with other arterial branches allowed for the practice of surgical maneuvering characteristic to aneurysm clipping. Furthermore, the relationship of the aneurysm dome with the surrounding structures allowed for better understanding of the aneurysmal local mass effect. Noticeably, all of these observations were done in a realistic environment provided by our customized embalming model for neurosurgical simulation. Conclusion. 3D aneurysms models implanted in cadaveric specimens may represent an untapped training method for replicating clip technique; for practicing certain approaches to aneurysms specific to a particular patient; and for improving neurosurgical research.

  16. Induction of continuous expanding infrarenal aortic aneurysms in a large porcine animal model

    DEFF Research Database (Denmark)

    Kloster, Brian Ozeraitis; Lund, Lars; Lindholt, Jes S.

    2015-01-01

    BACKGROUND: A large animal model with a continuous expanding infrarenal aortic aneurysm gives access to a more realistic AAA model with anatomy and physiology similar to humans, and thus allows for new experimental research in the natural history and treatment options of the disease. METHODS: 10...... ultrasound, hereafter the pigs were euthanized for inspection and AAA wall sampling for histological analysis. RESULTS: In group A, all pigs developed continuous expanding AAA's with a mean increase in AP-diameter to 16.26 ± 0.93 mm equivalent to a 57% increase. In group B the AP-diameters increased to 11...... in group A. The most frequent complication was a neurological deficit in the lower limbs. CONCLUSION: In pigs it's possible to induce continuous expanding AAA's based upon proteolytic degradation and pathological flow, resembling the real life dynamics of human aneurysms. Because the lumbars are preserved...

  17. Empirical Results of Modeling EUR/RON Exchange Rate using ARCH, GARCH, EGARCH, TARCH and PARCH models

    Directory of Open Access Journals (Sweden)

    Andreea – Cristina PETRICĂ

    2017-03-01

    Full Text Available The aim of this study consists in examining the changes in the volatility of daily returns of EUR/RON exchange rate using on the one hand symmetric GARCH models (ARCH and GARCH and on the other hand the asymmetric GARCH models (EGARCH, TARCH and PARCH, since the conditional variance is time-varying. The analysis takes into account daily quotations of EUR/RON exchange rate over the period of 04th January 1999 to 13th June 2016. Thus, we are modeling heteroscedasticity by applying different specifications of GARCH models followed by looking for significant parameters and low information criteria (minimum Akaike Information Criterion. All models are estimated using the maximum likelihood method under the assumption of several distributions of the innovation terms such as: Normal (Gaussian distribution, Student’s t distribution, Generalized Error distribution (GED, Student’s with fixed df. Distribution, and GED with fixed parameter distribution. The predominant models turned out to be EGARCH and PARCH models, and the empirical results point out that the best model for estimating daily returns of EUR/RON exchange rate is EGARCH(2,1 with Asymmetric order 2 under the assumption of Student’s t distributed innovation terms. This can be explained by the fact that in case of EGARCH model, the restriction regarding the positivity of the conditional variance is automatically satisfied.

  18. Significance of the spatial reconstruction based on mathematical modeling in the surgical treatment of giant intracranial aneurysms

    Directory of Open Access Journals (Sweden)

    Nikolić Igor M.

    2006-01-01

    Full Text Available Background. The use of computer models for the 3- dimensional reconstruction could be a reliable method to overcome technical imperfections of diagnostic procedures for the microsurgical operation of giant intracranial aneurysms. Case report. We presented a case of successfully operated 52-year-old woman with giant intracranial aneurysm, in which the computer 3-dimensional reconstruction of blood vessels and the aneurysmal neck had been decisive for making the diagnosis. The model for 3- dimensional reconstruction of blood vessels was based on the two 2-dimensional projections of the conventional angiography. Standard neuroradiologic diagnostic procedures showed a giant aneurysm on the left middle cerebral artery, but the conventional subtraction and CT angiography did not reveal enough information. By the use of a personal computer, we performed a 3-dimensional spatial reconstruction of the left carotid artery to visualize the neck of aneurysm and its supplying blood vessels. Conclusion. The 3-dimensional spatial reconstruction of the cerebral vessels of a giant aneurysm based on the conventional angiography could be useful for planning the surgical procedure.

  19. A microfabricated microfluidic bioMEMS device to model human brain aneurisms: the aneurysm-on-a-chip

    Science.gov (United States)

    Reece, Lisa M.; Khor, Jian Wei; Thakur, Raviraj; Amin, Ahmed; Wereley, Steven T.; Leary, James F.

    2015-03-01

    Aneurysms are pockets of blood that collect outside blood vessel walls forming dilatations and leaving arterial walls very prone to rupture. There is little information concerning the causes of intracranial aneurysm formation, growth, and rupture. Current treatments include: (1) clipping, and (2) coil embolization, including stent-assisted coiling. Further, the evolution of any aneurysm is assumed to be caused by the remodeling of the affected blood vessel's material constituents (tunica intima, tunica media, or tunica adventitia). Velocity, pressure, and wall shear stresses aid in the disease development of aneurysmal growth, while the shear force mechanisms effecting wound closure are elusive. To study aneurysm pathogenesis, a lab-on-a-chip device is the key to discovering the underlying mechanisms of these lesions. A two-dimensional microfluidic model, the Aneurysm-on-a-Chip™ (AOC), was the logical answer to study particle flow within an aneurysm "sac". The AOC apparatus can track particles/cells when it is coupled to particle image velocimetry software (PIV) package. The AOC fluid flow was visualized using standard microscopy techniques with commercial microparticles and human aortic smooth muscle cells (HASMC). Images were taken during fluid flow experiments and PIV was utilized to monitor the flow of particles within the "sac" region, as well as particles entering and exiting the device. Quiver plots were generated from fluid flow experiments using standard 7 μm latex particles and fixed HASMC in PBS. PIV analysis shows that the particles flowed nicely from input to output. Wall shear stress provided evidence that there was some back flow at the edges of the "sac" - an indicator of aneurysm development in human patients.

  20. Multilocular True Ulnar Artery Aneurysm in a Pediatric Patient

    OpenAIRE

    Stalder, Mark W.; Sanders, Christopher; Lago, Mary; Hilaire, Hugo St.

    2016-01-01

    Summary: Ulnar artery aneurysms are an exceedingly rare entity in the pediatric population and have no consistent etiologic mechanism. We present the case of a 15-year-old male with a multilocular ulnar artery aneurysm in the setting of no antecedent history of trauma, no identifiable connective tissue disorders, and no other apparent etiological factors. Furthermore, the patient’s arterial palmar arch system was absent. The aneurysm was resected, and arterial reconstruction was successfully ...

  1. Using ArchE in the Classroom: One Experience

    Science.gov (United States)

    2007-09-01

    displaying the new itinerary The team initially adopted the Model-View-Controller ( MVC ) architecture as the top-level architecture . The...CMU/SEI-2007-TN-001 Software Architecture Technology Initiative Unlimited distribution subject to the copyright. This report was prepared...SOFTWARE ENGINEERING INSTITUTE | v vi | CMU/SEI-2007-TN-001 Abstract The Architecture Expert (ArchE) tool serves as a software architecture

  2. 胸降主动脉瘤伴主动脉右弓右降手术的护理配合%Nursing cooperation in the operation of descending thoracic aortic aneurysm with right-sided aortic arch and right-sided descending aorta

    Institute of Scientific and Technical Information of China (English)

    李红; 翟跃军; 赵子英

    2010-01-01

    目的 探讨临床少见的右位主动脉弓、右位降主动脉、胸降主动脉瘤外科手术中的护理配合,以提高手术配合质量,减少手术相关并发症的发生.方法 针对8例行右弓、右降胸降主动脉瘤手术的病例进行术前准备、麻醉配合、体位管理和皮肤保护、术中配合、术后交接等护理配合.结果 8例患者于术后4~7 h清醒,无左上肢缺血、无皮肤压伤感染等护理问题.结论 术前心理护理、麻醉配合、正确的体位摆放以及充分显露术野和娴熟的手术配合是确保手术顺利进行的关键因素之一.%Objective To discuss the nursing cooperation in operation of right-sided aortic arch, rightsided descending aorta, descending thoracic aortic aneurysm, to provide basis for high quality of operative cooperation and complication reducing. Methods To carry out preoperative preparation, anesthesia cooperation, body position management, skin protection, operative cooperation, postoperative relay in 8 patients underwent operation of right-sided aortic arch, right-sided descending aorta, descending thoracic aortic aneurysm. Results 8 patients got consciousness 4 ~ 7 hours post operation, there were no left upper limb ischemia and compression injury infection. Conclusions Preoperative mental nursing, anesthesia cooperation,correct body position, sufficient surgery field exposure and expert operative cooperation are the key factors of success operation.

  3. Endovascular biopsy: Technical feasibility of novel endothelial cell harvesting devices assessed in a rabbit aneurysm model

    Science.gov (United States)

    Bauer, Diana; Sun, Zhengda; Stillson, Carol; Nelson, Jeffrey; Barry, David; Hetts, Steven W; Higashida, Randall T; Dowd, Christopher F; Halbach, Van V; Su, Hua; Saeed, Maythem M

    2015-01-01

    The lack of safe and reliable methods to sample vascular tissue in situ limits discovery of the underlying genetic and pathophysiological mechanisms of many vascular disorders, including aneurysms. We investigated the feasibility and comparable efficacy of in vivo vascular endothelial cell sampling using a spectrum of endovascular devices. Using the rabbit elastase carotid aneurysm model we evaluated the performance of existing aneurysmal coils, intracranial stents, and stent-like devices to collect vascular endothelial cells. Additionally, we modified a subset of devices to assess the effects of alterations to coil pitch, coil wire contour, and stent surface finishing. Device performance was evaluated by (1) the number of viable endothelial cells harvested, (2) the degree of vascular wall damage analyzed using digital subtraction angiography and histopathological analysis, and (3) the ease of device navigability and retrieval. Isolated cells underwent immunohistochemical analysis to confirm cell type and viability. Coil and stent specifications, technique, and endothelial cell counts were tabulated and statistical analysis performed. Using conventional detachable-type and modified aneurysm coils 11 of 14 (78.6%) harvested endothelial cells with a mean of 7.93 (±8.33) cells/coil, while 15 of 15 (100%) conventional stents, stent-like devices and modified stents harvested endothelial cells with a mean of 831.33 (±887.73) cells/device. Coil stiffness was significantly associated with endothelial cell count in univariate analysis (p = 0.044). For stents and stent-like devices univariate analysis demonstrated stent-to-aorta diameter ratios (p = 0.001), stent length (p = 0.049), and the use of a pulling retrieval technique (p = 0.019) significantly predictive of endothelial cell counts, though a multivariate model using these variables demonstrated only the stent-to-aorta diameter ratio (p = 0.029) predictive of endothelial cell counts. Modified

  4. In vitro and in vivo evaluation of a shape memory polymer foam-over-wire embolization device delivered in saccular aneurysm models.

    Science.gov (United States)

    Boyle, Anthony J; Landsman, Todd L; Wierzbicki, Mark A; Nash, Landon D; Hwang, Wonjun; Miller, Matthew W; Tuzun, Egemen; Hasan, Sayyeda M; Maitland, Duncan J

    2016-10-01

    Current endovascular therapies for intracranial saccular aneurysms result in high recurrence rates due to poor tissue healing, coil compaction, and aneurysm growth. We propose treatment of saccular aneurysms using shape memory polymer (SMP) foam to improve clinical outcomes. SMP foam-over-wire (FOW) embolization devices were delivered to in vitro and in vivo porcine saccular aneurysm models to evaluate device efficacy, aneurysm occlusion, and acute clotting. FOW devices demonstrated effective delivery and stable implantation in vitro. In vivo porcine aneurysms were successfully occluded using FOW devices with theoretical volume occlusion values greater than 72% and rapid, stable thrombus formation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1407-1415, 2016.

  5. Parametric modeling of arch dam based on Excel-VBA and APDL%基于Excel-VBA与APDL的拱坝参数化建模方法

    Institute of Scientific and Technical Information of China (English)

    周强

    2015-01-01

    Modeling of arch dam is growing more and more difficult as its complex shape. To get the re-quired coordinates of arch dam modeling, this paper does secondary development of Excel by VBA. And acquired coordinates could generate executable APDL code, which would make establishing double-cur-vature arch dam model more quickly and efficiently. It could save a lot of time for the next simulation analysis and calculation of arch dam. The result shows that the parameterized modeling of arch dam be-comes more convenient and accurate by the method combining Excel-VBA and APDL.%由于拱坝体形较为复杂,拱坝建模难度较大.笔者利用VBA对Excel进行二次开发,得出拱坝建模中所需的点坐标.根据这些点坐标生成ANSYS中可执行的APDL代码,快捷高效地建立了双曲拱坝模型,为此后的拱坝仿真计算创造了条件.实例表明,Excel-VBA与APDL的结合使用,可以使ANSYS中拱坝的参数化建模更为方便和准确.

  6. Brain Aneurysm

    Science.gov (United States)

    A brain aneurysm is an abnormal bulge or "ballooning" in the wall of an artery in the brain. They are sometimes called berry aneurysms because they ... often the size of a small berry. Most brain aneurysms produce no symptoms until they become large, ...

  7. Fluid-Structure Interaction in Abdominal Aortic Aneurysm: Effect of Modeling Techniques

    Directory of Open Access Journals (Sweden)

    Shengmao Lin

    2017-01-01

    Full Text Available In this work, the impact of modeling techniques on predicting the mechanical behaviors of abdominal aortic aneurysm (AAA is systematically investigated. The fluid-structure interaction (FSI model for simultaneously capturing the transient interaction between blood flow dynamics and wall mechanics was compared with its simplified techniques, that is, computational fluid dynamics (CFD or computational solid stress (CSS model. Results demonstrated that CFD exhibited relatively smaller vortexes and tends to overestimate the fluid wall shear stress, compared to FSI. On the contrary, the minimal differences in wall stresses and deformation were observed between FSI and CSS models. Furthermore, it was found that the accuracy of CSS prediction depends on the applied pressure profile for the aneurysm sac. A large pressure drop across AAA usually led to the underestimation of wall stresses and thus the AAA rupture. Moreover, the assumed isotropic AAA wall properties, compared to the anisotropic one, will aggravate the difference between the simplified models with the FSI approach. The present work demonstrated the importance of modeling techniques on predicting the blood flow dynamics and wall mechanics of the AAA, which could guide the selection of appropriate modeling technique for significant clinical implications.

  8. Fluid-Structure Interaction in Abdominal Aortic Aneurysm: Effect of Modeling Techniques.

    Science.gov (United States)

    Lin, Shengmao; Han, Xinwei; Bi, Yonghua; Ju, Siyeong; Gu, Linxia

    2017-01-01

    In this work, the impact of modeling techniques on predicting the mechanical behaviors of abdominal aortic aneurysm (AAA) is systematically investigated. The fluid-structure interaction (FSI) model for simultaneously capturing the transient interaction between blood flow dynamics and wall mechanics was compared with its simplified techniques, that is, computational fluid dynamics (CFD) or computational solid stress (CSS) model. Results demonstrated that CFD exhibited relatively smaller vortexes and tends to overestimate the fluid wall shear stress, compared to FSI. On the contrary, the minimal differences in wall stresses and deformation were observed between FSI and CSS models. Furthermore, it was found that the accuracy of CSS prediction depends on the applied pressure profile for the aneurysm sac. A large pressure drop across AAA usually led to the underestimation of wall stresses and thus the AAA rupture. Moreover, the assumed isotropic AAA wall properties, compared to the anisotropic one, will aggravate the difference between the simplified models with the FSI approach. The present work demonstrated the importance of modeling techniques on predicting the blood flow dynamics and wall mechanics of the AAA, which could guide the selection of appropriate modeling technique for significant clinical implications.

  9. Fluid-Structure Interaction in Abdominal Aortic Aneurysm: Effect of Modeling Techniques

    Science.gov (United States)

    Lin, Shengmao; Han, Xinwei; Bi, Yonghua; Ju, Siyeong

    2017-01-01

    In this work, the impact of modeling techniques on predicting the mechanical behaviors of abdominal aortic aneurysm (AAA) is systematically investigated. The fluid-structure interaction (FSI) model for simultaneously capturing the transient interaction between blood flow dynamics and wall mechanics was compared with its simplified techniques, that is, computational fluid dynamics (CFD) or computational solid stress (CSS) model. Results demonstrated that CFD exhibited relatively smaller vortexes and tends to overestimate the fluid wall shear stress, compared to FSI. On the contrary, the minimal differences in wall stresses and deformation were observed between FSI and CSS models. Furthermore, it was found that the accuracy of CSS prediction depends on the applied pressure profile for the aneurysm sac. A large pressure drop across AAA usually led to the underestimation of wall stresses and thus the AAA rupture. Moreover, the assumed isotropic AAA wall properties, compared to the anisotropic one, will aggravate the difference between the simplified models with the FSI approach. The present work demonstrated the importance of modeling techniques on predicting the blood flow dynamics and wall mechanics of the AAA, which could guide the selection of appropriate modeling technique for significant clinical implications. PMID:28321413

  10. Variable Density Flow Modeling for Simulation Framework for Regional Geologic CO{sub 2} Storage Along Arches Province of Midwestern United States

    Energy Technology Data Exchange (ETDEWEB)

    Joel Sminchak

    2011-09-30

    The Arches Province in the Midwestern U.S. has been identified as a major area for carbon dioxide (CO{sub 2}) storage applications because of the intersection of Mt. Simon sandstone reservoir thickness and permeability. To better understand large-scale CO{sub 2} storage infrastructure requirements in the Arches Province, variable density scoping level modeling was completed. Three main tasks were completed for the variable density modeling: Single-phase, variable density groundwater flow modeling; Scoping level multi-phase simulations; and Preliminary basin-scale multi-phase simulations. The variable density modeling task was successful in evaluating appropriate input data for the Arches Province numerical simulations. Data from the geocellular model developed earlier in the project were translated into preliminary numerical models. These models were calibrated to observed conditions in the Mt. Simon, suggesting a suitable geologic depiction of the system. The initial models were used to assess boundary conditions, calibrate to reservoir conditions, examine grid dimensions, evaluate upscaling items, and develop regional storage field scenarios. The task also provided practical information on items related to CO{sub 2} storage applications in the Arches Province such as pressure buildup estimates, well spacing limitations, and injection field arrangements. The Arches Simulation project is a three-year effort and part of the United States Department of Energy (U.S. DOE)/National Energy Technology Laboratory (NETL) program on innovative and advanced technologies and protocols for monitoring/verification/accounting (MVA), simulation, and risk assessment of CO{sub 2} sequestration in geologic formations. The overall objective of the project is to develop a simulation framework for regional geologic CO{sub 2} storage infrastructure along the Arches Province of the Midwestern U.S.

  11. Seismic damage analysis of the outlet piers of arch dams using the finite element sub-model method

    Science.gov (United States)

    Song, Liangfeng; Wu, Mingxin; Wang, Jinting; Xu, Yanjie

    2016-09-01

    This study aims to analyze seismic damage of reinforced outlet piers of arch dams by the nonlinear finite element (FE) sub-model method. First, the dam-foundation system is modeled and analyzed, in which the effects of infinite foundation, contraction joints, and nonlinear concrete are taken into account. The detailed structures of the outlet pier are then simulated with a refined FE model in the sub-model analysis. In this way the damage mechanism of the plain (unreinforced) outlet pier is analyzed, and the effects of two reinforcement measures (i.e., post-tensioned anchor cables and reinforcing bar) on the dynamic damage to the outlet pier are investigated comprehensively. Results show that the plain pier is damaged severely by strong earthquakes while implementation of post-tensioned anchor cables strengthens the pier effectively. In addition, radiation damping strongly alleviates seismic damage to the piers.

  12. Embryonic tongue morphogenesis in an organ culture model of mouse mandibular arches: blocking Sonic hedgehog signaling leads to microglossia.

    Science.gov (United States)

    Torii, Daisuke; Soeno, Yuuichi; Fujita, Kazuya; Sato, Kaori; Aoba, Takaaki; Taya, Yuji

    2016-01-01

    Mouse tongue development is initiated with the formation of lateral lingual swellings just before fusion between the mediodorsal surfaces of the mandibular arches at around embryonic day 11.0. Here, we investigated the role of Sonic hedgehog (Shh) signaling in embryonic mouse tongue morphogenesis. For this, we used an organ culture model of the mandibular arches from mouse embryos at embryonic day 10.5. When the Shh signaling inhibitor jervine was added to the culture medium for 24-96 h, the formation of lateral lingual swellings and subsequent epithelial invagination into the mesenchyme were impaired markedly, leading to a hypoplastic tongue with an incomplete oral sulcus. Notably, jervine treatment reduced the proliferation of non-myogenic mesenchymal cells at the onset of forming the lateral lingual swellings, whereas it did not affect the proliferation and differentiation of a myogenic cell lineage, which created a cell community at the central circumferential region of the lateral lingual swellings as seen in vivo and in control cultures lacking the inhibitor. Thus, epithelium-derived Shh signaling stimulates the proliferation of non-myogenic mesenchymal cells essential for forming lateral lingual swellings and contributes to epithelial invagination into the mesenchyme during early tongue development.

  13. Ambient Vibration Tests of an Arch Dam with Different Reservoir Water Levels: Experimental Results and Comparison with Finite Element Modelling

    Directory of Open Access Journals (Sweden)

    Sergio Vincenzo Calcina

    2014-01-01

    Full Text Available This paper deals with the ambient vibration tests performed in an arch dam in two different working conditions in order to assess the effect produced by two different reservoir water levels on the structural vibration properties. The study consists of an experimental part and a numerical part. The experimental tests were carried out in two different periods of the year, at the beginning of autumn (October 2012 and at the end of winter (March 2013, respectively. The measurements were performed using a fast technique based on asynchronous records of microtremor time-series. In-contact single-station measurements were done by means of one single high resolution triaxial tromometer and two low-frequency seismometers, placed in different points of the structure. The Standard Spectral Ratio method has been used to evaluate the natural frequencies of vibration of the structure. A 3D finite element model of the arch dam-reservoir-foundation system has been developed to verify analytically determined vibration properties, such as natural frequencies and mode shapes, and their changes linked to water level with the experimental results.

  14. Biomechanical effects of titanium implants with full arch bridge rehabilitation on a synthetic model of the human jaw.

    Science.gov (United States)

    De Santis, Roberto; Mollica, Francesco; Zarone, Fernando; Ambrosio, Luigi; Nicolais, Luigi

    2007-01-01

    A composite model of the mandible, constituted by an inner polymeric core and a glass fibre reinforced outer shell, has been developed and equipped with six ITI titanium implants and a full gold alloy arch bridge prosthesis. The effects of this oral rehabilitation on the biomechanics of the mandible are investigated through a simulation of the lateral component of the pterygoid muscles. These muscles are involved as the mouth is opened and closed, hence their activity is very frequent. An increase of the mandible stiffness due to the prosthesis is observed; moreover, the coupling of the relatively stiff rehabilitation devices with the natural tissue analogue leads to stress-shielding and stress-concentration in the incisal and molar regions, respectively. Although the amplitude of the force generated by pterygoid muscles is quite small, high strains over the incisal region are measured. A stress-shielding effect, of about 20%, is observed at the symphysis as the full arch bridge prosthesis is fixed on the implants. Therefore, the presence of the prosthesis leads to significant modification of the stress field experienced by the mandible, and this may be relevant in relation to the biomechanics of mandibular bone remodelling.

  15. Calculation Model of Equivalent Strength for Induced Crack Based on Double-K Fracture Theory and Its Optimizing Setting in RCC Arch Dam

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaogang; SONG Yupu; WU Zhimin

    2005-01-01

    By means of fracture testing on roller-compacted concrete (RCC) three-point bending beams with two different specimen sizes, the P-CMOD complete curve for RCC was gained. Furthermore, by applying double-K fracture theory, KiniⅠC,KunⅠC, as well as the critical effective crack length and the critical crack tip opening displacement, were evaluated. Based on the double-K fracture parameters above, the calculation model of equivalent strength for induced crack was established, thus the calculation method on its initiation, stable propagation and unstable fracture was ascertained. Moreover, the finite element simulation analysis of stress field in ShaPai arch dam and the on-site observational splaying points of induced crack at different altitudes validated the reliability of the model. Finally, crack inducer's optimal setting in RCC arch dam was studied. It improves the design level of induced crack in RCC arch dam and satisfies the necessity of engineering practice.

  16. Magnesium alloy covered stent for treatment of a lateral aneurysm model in rabbit common carotid artery: An in vivo study

    Science.gov (United States)

    Wang, Wu; Wang, Yong-Li; Chen, Mo; Chen, Liang; Zhang, Jian; Li, Yong-Dong; Li, Ming-Hua; Yuan, Guang-Yin

    2016-11-01

    Magnesium alloy covered stents have rarely been used in the common carotid artery (CCA). We evaluated the long-term efficacy of magnesium alloy covered stents in a lateral aneurysm model in rabbit CCA. Magnesium alloy covered stents (group A, n = 7) or Willis covered stents (group B, n = 5) were inserted in 12 New Zealand White rabbits and they were followed up for 12 months. The long-term feasibility for aneurysm occlusion was studied through angiograms; the changes in vessel area and lumen area were assessed with IVUS. Complete aneurysmal occlusion was achieved in all aneurysms. Angiography showed that the diameter of the stented CCA in group A at 6 and 12 months was significantly greater than the diameter immediately after stent placement. On intravascular ultrasound (IVUS) examination, the mean lumen area of the stented CCA in group A was significantly greater at 6 and 12 months than that immediately after stent placement; the mean lumen area was also significantly greater in group A than in group B at the same time points. The magnesium alloy covered stents proved to be an effective approach for occlusion of lateral aneurysm in the rabbit CCA; it provides distinct advantages that are comparable to that obtained with the Willis covered stent.

  17. Influence of scanning and reconstruction parameters on quality of three-dimensional surface models of the dental arches from cone beam computed tomography

    NARCIS (Netherlands)

    Hassan, B.; Souza, P.C.; Jacobs, R.; Berti, S.D.; van der Stelt, P.

    2010-01-01

    The study aim is to investigate the influence of scan field, mouth opening, voxel size, and segmentation threshold selections on the quality of the three-dimensional (3D) surface models of the dental arches from cone beam computed tomography (CBCT). 3D models of 25 patients scanned with one image in

  18. Modeling contrast agent flow in cerebral aneurysms: comparison of CFD with medical imaging

    Science.gov (United States)

    Rayz, Vitaliy; Vali, Alireza; Sigovan, Monica; Lawton, Michael; Saloner, David; Boussel, Loic

    2016-11-01

    PURPOSE: The flow in cerebral aneurysms is routinely assessed with X-ray angiography, an imaging technique based on a contrast agent injection. In addition to requiring a patient's catheterization and radiation exposure, the X-ray angiography may inaccurately estimate the flow residence time, as the injection alters the native blood flow patterns. Numerical modeling of the contrast transport based on MRI imaging, provides a non-invasive alternative for the flow diagnostics. METHODS: The flow in 3 cerebral aneurysms was measured in vivo with 4D PC-MRI, which provides time-resolved, 3D velocity field. The measured velocities were used to simulate a contrast agent transport by solving the advection-diffusion equation. In addition, the flow in the same patient-specific geometries was simulated with CFD and the velocities obtained from the Navier-Stokes solution were used to model the transport of a virtual contrast. RESULTS: Contrast filling and washout patterns obtained in simulations based on MRI-measured velocities were in agreement with those obtained using the Navier-Stokes solution. Some discrepancies were observed in comparison to the X-ray angiography data, as numerical modeling of the contrast transport is based on the native blood flow unaffected by the contrast injection. NIH HL115267.

  19. 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.

  20. PIV Measurement of Wall Shear Stress and Flow Structures within an Intracranial Aneurysm Model

    Science.gov (United States)

    Chow, Ricky; Sparrow, Eph; Campbell, Gary; Divani, Afshin; Sheng, Jian

    2012-11-01

    The formation and rupture of an intracranial aneurysm (IA) is a debilitating and often lethal event. Geometric features of the aneurysm bulb and upstream artery, such as bulb size, bulb shape, and curvature of the artery, are two groups of factors that define the flow and stresses within an IA. Abnormal flow stresses are related to rupture. This presentation discusses the development of a quasi-3D PIV technique and its application in various glass models at Re = 275 and 550 to experimentally assess at a preliminary level the impact of geometry and flow rate. Some conclusions are to be drawn linking geometry of the flow domain to rupture risk. The extracted results also serve as the baseline case and as a precursor to a companion presentation by the authors discussing the impact of flow diverters, a new class of medical devices. The PIV experiments were performed in a fully index-matched flow facility, allowing for unobstructed observations over complex geometry. A reconstruction and analysis method was devised to obtain 3D mean wall stress distributions and flow fields. The quasi 3D measurements were reconstructed from orthogonal planes encompassing the entire glass model, spaced 0.4mm apart. Wall shear stresses were evaluated from the near-wall flow viscous stresses.

  1. Flow of a blood analogue fluid in a compliant abdominal aortic aneurysm model: experimental modelling.

    Science.gov (United States)

    Deplano, Valérie; Knapp, Yannick; Bailly, Lucie; Bertrand, Eric

    2014-04-11

    The aim of this work is to develop a unique in vitro set-up in order to analyse the influence of the shear thinning fluid-properties on the flow dynamics within the bulge of an abdominal aortic aneurysm (AAA). From an experimental point of view, the goals are to elaborate an analogue shear thinning fluid mimicking the macroscopic blood behaviour, to characterise its rheology at low shear rates and to propose an experimental device able to manage such an analogue fluid without altering its feature while reproducing physiological flow rate and pressure, through compliant AAA. Once these experimental prerequisites achieved, the results obtained in the present work show that the flow dynamics is highly dependent on the fluid rheology. The main results point out that the propagation of the vortex ring, generated in the AAA bulge, is slower for shear thinning fluids inducing a smaller travelled distance by the vortex ring so that it never impacts the anterior wall in the distal region, in opposition to Newtonian fluids. Moreover, scalar shear rate values are globally lower for shear thinning fluids inducing higher maximum stress values than those for the Newtonian fluids. Consequently, this work highlights that a Newtonian fluid model is finally inadequate to obtain a reliable prediction of the flow dynamics within AAA.

  2. Fractional modeling of viscoelasticity in 3D cerebral arteries and aneurysms

    Science.gov (United States)

    Yu, Yue; Perdikaris, Paris; Karniadakis, George Em

    2016-10-01

    We develop efficient numerical methods for fractional order PDEs, and employ them to investigate viscoelastic constitutive laws for arterial wall mechanics. Recent simulations using one-dimensional models [1] have indicated that fractional order models may offer a more powerful alternative for modeling the arterial wall response, exhibiting reduced sensitivity to parametric uncertainties compared with the integer-calculus-based models. Here, we study three-dimensional (3D) fractional PDEs that naturally model the continuous relaxation properties of soft tissue, and for the first time employ them to simulate flow structure interactions for patient-specific brain aneurysms. To deal with the high memory requirements and in order to accelerate the numerical evaluation of hereditary integrals, we employ a fast convolution method [2] that reduces the memory cost to O (log ⁡ (N)) and the computational complexity to O (Nlog ⁡ (N)). Furthermore, we combine the fast convolution with high-order backward differentiation to achieve third-order time integration accuracy. We confirm that in 3D viscoelastic simulations, the integer order models strongly depends on the relaxation parameters, while the fractional order models are less sensitive. As an application to long-time simulations in complex geometries, we also apply the method to modeling fluid-structure interaction of a 3D patient-specific compliant cerebral artery with an aneurysm. Taken together, our findings demonstrate that fractional calculus can be employed effectively in modeling complex behavior of materials in realistic 3D time-dependent problems if properly designed efficient algorithms are employed to overcome the extra memory requirements and computational complexity associated with the non-local character of fractional derivatives.

  3. Patient-Specific Simulation Models of the Abdominal Aorta With and Without Aneurysms

    DEFF Research Database (Denmark)

    Enevoldsen, Marie Sand

    This research study presents computational simulation models for analysis of parameters which are in evidence of development and clinical management of abdominal aortic aneurysms (AAA). The research covers three main areas: interpretation of material parameters, implementation of the constitutive....... The collagen fibers are grouped in four directions of orientation. The purpose of the first study was to investigate whether significant risk factors related to AAA development can be identified from a specific pattern in the material parameters of the 4FF model. Smoking is a leading self-inflicted risk factor...... to be isotropic, which may allow simpler phenomenological models to capture these effects. There is a pressing need, however, for more detailed histological information coupled with more complete experimental data for the systemic arteries. The second study was aimed at developing computational simulation models...

  4. Physiologically-relevant measurements of flow through coils and stents: towards improved modeling of endovascular treatment of intracranial aneurysms

    Science.gov (United States)

    Barbour, Michael; Levitt, Michael; Geindreau, Christian; Rolland Du Roscoat, Sabine; Johnson, Luke; Chivukula, Keshav; Aliseda, Alberto

    2016-11-01

    The hemodynamic environment in cerebral aneurysms undergoing flow-diverting stent (FDS) or coil embolization treatment plays a critical role in long-term outcomes. Standard modeling approaches to endovascular coils and FDS simplify the complex geometry into a homogenous porous volume or surface through the addition of a Darcy-Brinkman pressure loss term in the momentum equation. The inertial and viscous loss coefficients are typically derived from published in vitro studies of pressure loss across FDS and coils placed in a straight tube, where the only fluid path is across the treatment - an unrealistic representation of treatment apposition in vivo. The pressure drop across FDS and coils in side branch aneurysms located on curved parent vessels is measured. Using PIV, the velocity at the aneurysm neck plane is reconstructed and used to determine loss coefficients for better models of endovascular coils or FDS that account for physiological placement and vessel curvature. These improved models are incorporated into CFD simulations and validated against in vitro model PIV velocity, as well as compared to microCT-based coil/stent-resolving CFD simulations of patient-specific treated aneurysm flow.

  5. Modeling and visualization techniques for virtual stenting of aneurysms and stenoses.

    Science.gov (United States)

    Egger, Jan; Grosskopf, Stefan; Nimsky, Christopher; Kapur, Tina; Freisleben, Bernd

    2012-04-01

    In this work, we present modeling and visualization techniques for virtual stenting of aneurysms and stenoses. In particular, contributions to support the computer-aided treatment of artery diseases - artery enlargement (aneurysm) and artery contraction (stenosis) - are made. If an intervention takes place, there are two different treatment alternatives for this kind of artery diseases: open surgery and minimally invasive (endovascular) treatment. Computer-assisted optimization of endovascular treatments is the main focus of our work. In addition to stent simulation techniques, we also present a computer-aided simulation of endoluminal catheters to support the therapy-planning phase. The stent simulation is based on a three-dimensional Active Contour Method and is applicable to both non-bifurcated (I-stents) and bifurcated stents (Y-stents). All methods are introduced in detail and are evaluated with phantom datasets as well as with real patient data from the clinical routine. Additionally, the clinical prototype that is based upon these methods is described.

  6. Three-band decomposition analysis in multiscale FSI models of abdominal aortic aneurysms

    Science.gov (United States)

    Nestola, Maria G. C.; Gizzi, Alessio; Cherubini, Christian; Filippi, Simonetta

    2016-07-01

    Computational modeling plays an important role in biology and medicine to assess the effects of hemodynamic alterations in the onset and development of vascular pathologies. Synthetic analytic indices are of primary importance for a reliable and effective a priori identification of the risk. In this scenario, we propose a multiscale fluid-structure interaction (FSI) modeling approach of hemodynamic flows, extending the recently introduced three-band decomposition (TBD) analysis for moving domains. A quantitative comparison is performed with respect to the most common hemodynamic risk indicators in a systematic manner. We demonstrate the reliability of the TBD methodology also for deformable domains by assuming a hyperelastic formulation of the arterial wall and a Newtonian approximation of the blood flow. Numerical simulations are performed for physiologic and pathologic axially symmetric geometry models with particular attention to abdominal aortic aneurysms (AAAs). Risk assessment, limitations and perspectives are finally discussed.

  7. Computational Fluid Dynamics modeling of contrast transport in basilar aneurysms following flow-altering surgeries.

    Science.gov (United States)

    Vali, Alireza; Abla, Adib A; Lawton, Michael T; Saloner, David; Rayz, Vitaliy L

    2017-01-04

    In vivo measurement of blood velocity fields and flow descriptors remains challenging due to image artifacts and limited resolution of current imaging methods; however, in vivo imaging data can be used to inform and validate patient-specific computational fluid dynamics (CFD) models. Image-based CFD can be particularly useful for planning surgical interventions in complicated cases such as fusiform aneurysms of the basilar artery, where it is crucial to alter pathological hemodynamics while preserving flow to the distal vasculature. In this study, patient-specific CFD modeling was conducted for two basilar aneurysm patients considered for surgical treatment. In addition to velocity fields, transport of contrast agent was simulated for the preoperative and postoperative conditions using two approaches. The transport of a virtual contrast passively following the flow streamlines was simulated to predict post-surgical flow regions prone to thrombus deposition. In addition, the transport of a mixture of blood with an iodine-based contrast agent was modeled to compare and verify the CFD results with X-ray angiograms. The CFD-predicted patterns of contrast flow were qualitatively compared to in vivo X-ray angiograms acquired before and after the intervention. The results suggest that the mixture modeling approach, accounting for the flow rates and properties of the contrast injection, is in better agreement with the X-ray angiography data. The virtual contrast modeling assessed the residence time based on flow patterns unaffected by the injection procedure, which makes the virtual contrast modeling approach better suited for prediction of thrombus deposition, which is not limited to the peri-procedural state.

  8. A comparison of modelling techniques for computing wall stress in abdominal aortic aneurysms

    Directory of Open Access Journals (Sweden)

    McGloughlin Timothy M

    2007-10-01

    Full Text Available Abstract Background Aneurysms, in particular abdominal aortic aneurysms (AAA, form a significant portion of cardiovascular related deaths. There is much debate as to the most suitable tool for rupture prediction and interventional surgery of AAAs, and currently maximum diameter is used clinically as the determining factor for surgical intervention. Stress analysis techniques, such as finite element analysis (FEA to compute the wall stress in patient-specific AAAs, have been regarded by some authors to be more clinically important than the use of a "one-size-fits-all" maximum diameter criterion, since some small AAAs have been shown to have higher wall stress than larger AAAs and have been known to rupture. Methods A patient-specific AAA was selected from our AAA database and 3D reconstruction was performed. The AAA was then modelled in this study using three different approaches, namely, AAA(SIMP, AAA(MOD and AAA(COMP, with each model examined using linear and non-linear material properties. All models were analysed using the finite element method for wall stress distributions. Results Wall stress results show marked differences in peak wall stress results between the three methods. Peak wall stress was shown to reduce when more realistic parameters were utilised. It was also noted that wall stress was shown to reduce by 59% when modelled using the most accurate non-linear complex approach, compared to the same model without intraluminal thrombus. Conclusion The results here show that using more realistic parameters affect resulting wall stress. The use of simplified computational modelling methods can lead to inaccurate stress distributions. Care should be taken when examining stress results found using simplified techniques, in particular, if the wall stress results are to have clinical importance.

  9. Modelos animais de aneurisma de aorta Animal models of aortic aneurysm

    Directory of Open Access Journals (Sweden)

    Rodrigo Argenta

    2009-06-01

    Full Text Available Os modelos experimentais em animais vêm sendo utilizados em cirurgia vascular há décadas. O desenvolvimento de novas técnicas para tratamento endovascular dos aneurismas requer a criação de bons modelos experimentais para testar esses dispositivos e estudar seu impacto sobre a progressão da doença. Este artigo tem por objetivo revisar os modelos de aneurisma arterial descritos atualmente. Entre os diversos modelos descritos, nenhum reúne todas as características de um modelo ideal de aneurisma. Os modelos em animais de grande porte são adequados para treino, estudo de alterações em parâmetros fisiológicos durante e após a liberação dos dispositivos e integração do mesmo à parede do vaso. Algumas desvantagens significantes incluem dificuldade do manejo, alto custo, difícil manutenção e regulamentações legais, dificultando a disponibilidade de diversas espécies animais. Modelos em animais menores, como os coelhos e camundongos, embora sejam menos caros e de fácil obtenção, não são adequados para estudos de técnicas endovasculares pelas pequenas dimensões de seus vasos. Nenhum modelo descrito até o momento consegue reproduzir todas as características dos aneurismas observados em humanos. Modelos disponíveis são descritos nesta revisão, e suas vantagens e desvantagens são discutidas.Experimental animal models have been used in vascular surgery for decades. The development of new interventional techniques in the endovascular treatment of aneurysms requires the creation of good experimental models to test these devices and study their impact on disease progression. The aim of this article was to review arterial aneurysm models currently available. Several distinct models have been described but none of them satisfies all the requirements of an ideal aneurysm model. Large animal models are appropriate for training, study of alterations in physiological parameters during and after device delivery, and integration

  10. Thermal modeling of the NASA-Ames Research Center Cryogenic Optical Test Facility and a single-arch, fused-natural-quartz mirror

    Science.gov (United States)

    Ng, Y. S.; Augason, Gordon C.; Young, Jeffrey A.; Howard, Steven D.; Melugin, Ramsey K.

    1990-11-01

    A thermal model of the dewar and optical system of the Cryogenic Optical Test Facility at NASA-Ames Research Center was developed using the computer codes SINDA and MONTE CARLO. The model was based on the geometry, boundary conditions, and physical properties of the test facility and was developed to investigate heat transfer mechanisms and temperatures in the facility and in test mirrors during cryogenic optical tests. A single-arch, fused-natural-quartz mirror was the first mirror whose thermal loads and temperature distributions were modeled. From the temperature distribution, the thermal gradients in the mirror were obtained. The model predicted that a small gradient should exist for the single arch mirror. This was later verified by the measurement of mirror temperatures. The temperatures, predicted by the model at various locations within the dewar, were in relatively good agreement with the measured temperatures. The model is applicable to both steady-state and transient cooldown operations.

  11. Thermal modeling of the NASA-Ames Research Center Cryogenic Optical Test Facility and a single-arch, fused-natural-quartz mirror

    Science.gov (United States)

    Ng, Y. S.; Augason, Gordon C.; Young, Jeffrey A.; Howard, Steven D.; Melugin, Ramsey K.

    1990-01-01

    A thermal model of the dewar and optical system of the Cryogenic Optical Test Facility at NASA-Ames Research Center was developed using the computer codes SINDA and MONTE CARLO. The model was based on the geometry, boundary conditions, and physical properties of the test facility and was developed to investigate heat transfer mechanisms and temperatures in the facility and in test mirrors during cryogenic optical tests. A single-arch, fused-natural-quartz mirror was the first mirror whose thermal loads and temperature distributions were modeled. From the temperature distribution, the thermal gradients in the mirror were obtained. The model predicted that a small gradient should exist for the single arch mirror. This was later verified by the measurement of mirror temperatures. The temperatures, predicted by the model at various locations within the dewar, were in relatively good agreement with the measured temperatures. The model is applicable to both steady-state and transient cooldown operations.

  12. 三维数字化牙模的牙弓线探测%Dental Arch Detection of 3D Dental Model

    Institute of Scientific and Technical Information of China (English)

    袁天然; 廖文和; 戴宁; 崔海华; 王长伟; 俞青

    2008-01-01

    提出了一种在三维数字化牙颌模型上直接探测牙弓线的方法.首先,根据给定的顶点法向和咬合面的夹角阈值过滤出初始特征点,并拟和得到初始牙弓线;其次,对初始特征点集进行等分并找出对应的局部最高顶点,对局部最高顶点进行拟和得到最终的牙弓线.通过对多副牙颌模型的实验表明,所提方法稳定、有效.%A robust detection method for dental arch directly applied on 3D dental model was proposed which could be easily acquired through intra or extra oral measurement methods. Firstly, the initial dental arch was obtained through fitting the initial feature points filtered out according to the given threshold of the angle between the normal of the model point and the occlusal plane. Then the set of the initial feature points was divided into subsets using planes perpendicular to the initial dental arch with equal arch length between each two adjacent planes. The local peak point was found out for each subset according to the distance value between the point of the corresponding subset and the occlusal plane, and the curve fitting to the local peak points was also the final dental arch. The method was tested on models with various types of malocclusions and is proved to be robust and accurate.

  13. Accuracy and reproducibility of voxel based superimposition of cone beam computed tomography models on the anterior cranial base and the zygomatic arches.

    Directory of Open Access Journals (Sweden)

    Rania M Nada

    Full Text Available Superimposition of serial Cone Beam Computed Tomography (CBCT scans has become a valuable tool for three dimensional (3D assessment of treatment effects and stability. Voxel based image registration is a newly developed semi-automated technique for superimposition and comparison of two CBCT scans. The accuracy and reproducibility of CBCT superimposition on the anterior cranial base or the zygomatic arches using voxel based image registration was tested in this study. 16 pairs of 3D CBCT models were constructed from pre and post treatment CBCT scans of 16 adult dysgnathic patients. Each pair was registered on the anterior cranial base three times and on the left zygomatic arch twice. Following each superimposition, the mean absolute distances between the 2 models were calculated at 4 regions: anterior cranial base, forehead, left and right zygomatic arches. The mean distances between the models ranged from 0.2 to 0.37 mm (SD 0.08-0.16 for the anterior cranial base registration and from 0.2 to 0.45 mm (SD 0.09-0.27 for the zygomatic arch registration. The mean differences between the two registration zones ranged between 0.12 to 0.19 mm at the 4 regions. Voxel based image registration on both zones could be considered as an accurate and a reproducible method for CBCT superimposition. The left zygomatic arch could be used as a stable structure for the superimposition of smaller field of view CBCT scans where the anterior cranial base is not visible.

  14. Brain aneurysm repair

    Science.gov (United States)

    ... aneurysm repair; Dissecting aneurysm repair; Endovascular aneurysm repair - brain; Subarachnoid hemorrhage - aneurysm ... Your scalp, skull, and the coverings of the brain are opened. A metal clip is placed at ...

  15. Abdominal Aortic Aneurysm (AAA)

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Abdominal Aortic Aneurysm (AAA) Abdominal aortic aneurysm (AAA) occurs when atherosclerosis ... an abdominal aortic aneurysm treated? What is an abdominal aortic aneurysm? The aorta, the largest artery in the body, ...

  16. Conceptual Model Summary Report Simulation Framework for Regional Geologic CO2 Storage Along Arches Province of Midwestern United States

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2011-06-30

    A conceptual model was developed for the Arches Province that integrates geologic and hydrologic information on the Eau Claire and Mt. Simon formations into a geocellular model. The conceptual model describes the geologic setting, stratigraphy, geologic structures, hydrologic features, and distribution of key hydraulic parameters. The conceptual model is focused on the Mt. Simon sandstone and Eau Claire formations. The geocellular model depicts the parameters and conditions in a numerical array that may be imported into the numerical simulations of carbon dioxide (CO2) storage. Geophysical well logs, rock samples, drilling logs, geotechnical test results, and reservoir tests were evaluated for a 500,000 km2 study area centered on the Arches Province. The geologic and hydraulic data were integrated into a three-dimensional (3D) grid of porosity and permeability, which are key parameters regarding fluid flow and pressure buildup due to CO2 injection. Permeability data were corrected in locations where reservoir tests have been performed in Mt. Simon injection wells. The final geocellular model covers an area of 600 km by 600 km centered on the Arches Province. The geocellular model includes a total of 24,500,000 cells representing estimated porosity and permeability distribution. CO2 injection scenarios were developed for on-site and regional injection fields at rates of 70 to 140 million metric tons per year.

  17. A structural equation model to investigate the impact of missing occlusal units on objective masticatory function in patients with shortened dental arches.

    Science.gov (United States)

    Fueki, K; Yoshida, E; Igarashi, Y

    2011-11-01

    The aim of this study was to investigate the impact of missing occlusal units (MOUs) on objective masticatory function with respect to food comminuting and mixing ability. Sixty partially dentate patients (mean age, 64·1 years) with shortened dental arches participated in the study. Food comminuting ability was assessed using a masticatory performance test with peanuts as a test food. Food mixing ability was assessed using a mixing ability test with a two-coloured wax cube. Maximum bite force (MBF) was measured using a pressure-sensitive film as a mediator for food comminuting and mixing ability. A structural equation model was constructed based on a hypothesis that MOUs would be associated with reduced MBF and impairment of food comminuting and mixing ability. Structural equation modelling analysis found significant direct effects of MOU on median particle size and mixing ability index (MAI) (P dental arches.

  18. Nonlinear Dynamics of Electrostatically Actuated MEMS Arches

    KAUST Repository

    Al Hennawi, Qais M.

    2015-05-01

    In this thesis, we present theoretical and experimental investigation into the nonlinear statics and dynamics of clamped-clamped in-plane MEMS arches when excited by an electrostatic force. Theoretically, we first solve the equation of motion using a multi- mode Galarkin Reduced Order Model (ROM). We investigate the static response of the arch experimentally where we show several jumps due to the snap-through instability. Experimentally, a case study of in-plane silicon micromachined arch is studied and its mechanical behavior is measured using optical techniques. We develop an algorithm to extract various parameters that are needed to model the arch, such as the induced axial force, the modulus of elasticity, and the initially induced initial rise. After that, we excite the arch by a DC electrostatic force superimposed to an AC harmonic load. A softening spring behavior is observed when the excitation is close to the first resonance frequency due to the quadratic nonlinearity coming from the arch geometry and the electrostatic force. Also, a hardening spring behavior is observed when the excitation is close to the third (second symmetric) resonance frequency due to the cubic nonlinearity coming from mid-plane stretching. Then, we excite the arch by an electric load of two AC frequency components, where we report a combination resonance of the summed type. Agreement is reported among the theoretical and experimental work.

  19. 3D Modeling of Murine Abdominal Aortic Aneurysms: Quantification of Segmentation and Volumetric Reconstruction

    OpenAIRE

    Sarmiento, Paula A; Adelsperger, Amelia R; Goergen, Craig J.

    2016-01-01

    Abdominal Aortic Aneurysms (AAA) cause 5,900 deaths in the United States each year. Surgical intervention is clinically studied by non-invasive techniques such as computed tomography and magnetic resonance imaging. However, three-dimensional (3D) ultrasound imaging has become an inexpensive alternative and useful tool to characterize aneurysms, allowing for reconstruction of the vessel, quantification of hemodynamics through computational fluid dynamics (CFD) simulation, and possible predicti...

  20. Development of a novel rabbit model of abdominal aortic aneurysm via a combination of periaortic calcium chloride and elastase incubation.

    Directory of Open Access Journals (Sweden)

    Yonghua Bi

    Full Text Available BACKGROUND: The purpose of this study was to introduce a novel, simple and effective technique for creating a reliable rabbit model of abdominal aortic aneurysm (AAA via a combination of periaortic calcium chloride (CaCl2 and elastase incubation. METHODS: Forty-eight New Zealand white rabbits were divided into four groups. The AAA model was developed via a 20-minute periaortic incubation of CaCl2 (0.5 mol/L and elastase (1 Unit/µL in a 1.5-cm aortic segment (Group CE. A single incubation of CaCl2 (Group C or elastase (Group E and a sham operation group (Sham Group were used for the controls. Diameter was measured by serial digital subtraction angiography imaging on days 5, 15 and 30. Animals were sacrificed on day 5 and day 30 for histopathological and immunohistochemical studies. RESULTS: All animals in Group CE developed aneurysm, with an average dilation ratio of 65.3% ± 8.9% on day 5, 86.5% ± 28.7% on day 15 and 203.6% ± 39.1% on day 30. No aneurysm was found in Group C, and only one aneurysm was seen on day 5 in Group E. Group CE exhibited less intima-media thickness, endothelial recovery, elastin and smooth muscle cell (SMC content, but stronger expression of matrix metalloproteinase-2, matrix metalloproteinase-9 and RAM11 compared to the controls. CONCLUSIONS: The novel rabbit model of AAA created by using a combination of periaortic CaCl2 and elastase incubation is simple and effective to perform and is valuable for elucidating AAA mechanisms and therapeutic interventions in experimental studies.

  1. Lattice Boltzmann Model of 3D Multiphase Flow in Artery Bifurcation Aneurysm Problem.

    Science.gov (United States)

    Abas, Aizat; Mokhtar, N Hafizah; Ishak, M H H; Abdullah, M Z; Ho Tian, Ang

    2016-01-01

    This paper simulates and predicts the laminar flow inside the 3D aneurysm geometry, since the hemodynamic situation in the blood vessels is difficult to determine and visualize using standard imaging techniques, for example, magnetic resonance imaging (MRI). Three different types of Lattice Boltzmann (LB) models are computed, namely, single relaxation time (SRT), multiple relaxation time (MRT), and regularized BGK models. The results obtained using these different versions of the LB-based code will then be validated with ANSYS FLUENT, a commercially available finite volume- (FV-) based CFD solver. The simulated flow profiles that include velocity, pressure, and wall shear stress (WSS) are then compared between the two solvers. The predicted outcomes show that all the LB models are comparable and in good agreement with the FVM solver for complex blood flow simulation. The findings also show minor differences in their WSS profiles. The performance of the parallel implementation for each solver is also included and discussed in this paper. In terms of parallelization, it was shown that LBM-based code performed better in terms of the computation time required.

  2. Lattice Boltzmann Model of 3D Multiphase Flow in Artery Bifurcation Aneurysm Problem

    Directory of Open Access Journals (Sweden)

    Aizat Abas

    2016-01-01

    Full Text Available This paper simulates and predicts the laminar flow inside the 3D aneurysm geometry, since the hemodynamic situation in the blood vessels is difficult to determine and visualize using standard imaging techniques, for example, magnetic resonance imaging (MRI. Three different types of Lattice Boltzmann (LB models are computed, namely, single relaxation time (SRT, multiple relaxation time (MRT, and regularized BGK models. The results obtained using these different versions of the LB-based code will then be validated with ANSYS FLUENT, a commercially available finite volume- (FV- based CFD solver. The simulated flow profiles that include velocity, pressure, and wall shear stress (WSS are then compared between the two solvers. The predicted outcomes show that all the LB models are comparable and in good agreement with the FVM solver for complex blood flow simulation. The findings also show minor differences in their WSS profiles. The performance of the parallel implementation for each solver is also included and discussed in this paper. In terms of parallelization, it was shown that LBM-based code performed better in terms of the computation time required.

  3. Multilocular True Ulnar Artery Aneurysm in a Pediatric Patient.

    Science.gov (United States)

    Stalder, Mark W; Sanders, Christopher; Lago, Mary; Hilaire, Hugo St

    2016-01-01

    Ulnar artery aneurysms are an exceedingly rare entity in the pediatric population and have no consistent etiologic mechanism. We present the case of a 15-year-old male with a multilocular ulnar artery aneurysm in the setting of no antecedent history of trauma, no identifiable connective tissue disorders, and no other apparent etiological factors. Furthermore, the patient's arterial palmar arch system was absent. The aneurysm was resected, and arterial reconstruction was successfully performed via open surgical approach with cephalic vein interposition graft. We believe this treatment modality should be considered as the primary approach in all of these pediatric cases in consideration of the possible pitfalls of less comprehensive measures.

  4. Fluid-Structure Interaction Modeling of Intracranial Aneurysm Hemodynamics: Effects of Different Assumptions

    Science.gov (United States)

    Rajabzadeh Oghaz, Hamidreza; Damiano, Robert; Meng, Hui

    2015-11-01

    Intracranial aneurysms (IAs) are pathological outpouchings of cerebral vessels, the progression of which are mediated by complex interactions between the blood flow and vasculature. Image-based computational fluid dynamics (CFD) has been used for decades to investigate IA hemodynamics. However, the commonly adopted simplifying assumptions in CFD (e.g. rigid wall) compromise the simulation accuracy and mask the complex physics involved in IA progression and eventual rupture. Several groups have considered the wall compliance by using fluid-structure interaction (FSI) modeling. However, FSI simulation is highly sensitive to numerical assumptions (e.g. linear-elastic wall material, Newtonian fluid, initial vessel configuration, and constant pressure outlet), the effects of which are poorly understood. In this study, a comprehensive investigation of the sensitivity of FSI simulations in patient-specific IAs is investigated using a multi-stage approach with a varying level of complexity. We start with simulations incorporating several common simplifications: rigid wall, Newtonian fluid, and constant pressure at the outlets, and then we stepwise remove these simplifications until the most comprehensive FSI simulations. Hemodynamic parameters such as wall shear stress and oscillatory shear index are assessed and compared at each stage to better understand the sensitivity of in FSI simulations for IA to model assumptions. Supported by the National Institutes of Health (1R01 NS 091075-01).

  5. CFD Modelling of Abdominal Aortic Aneurysm on Hemodynamic Loads Using a Realistic Geometry with CT

    Directory of Open Access Journals (Sweden)

    Eduardo Soudah

    2013-01-01

    Full Text Available The objective of this study is to find a correlation between the abdominal aortic aneurysm (AAA geometric parameters, wall stress shear (WSS, abdominal flow patterns, intraluminal thrombus (ILT, and AAA arterial wall rupture using computational fluid dynamics (CFD. Real AAA 3D models were created by three-dimensional (3D reconstruction of in vivo acquired computed tomography (CT images from 5 patients. Based on 3D AAA models, high quality volume meshes were created using an optimal tetrahedral aspect ratio for the whole domain. In order to quantify the WSS and the recirculation inside the AAA, a 3D CFD using finite elements analysis was used. The CFD computation was performed assuming that the arterial wall is rigid and the blood is considered a homogeneous Newtonian fluid with a density of 1050 kg/m3 and a kinematic viscosity of 4×10-3 Pa·s. Parallelization procedures were used in order to increase the performance of the CFD calculations. A relation between AAA geometric parameters (asymmetry index (β, saccular index (γ, deformation diameter ratio (χ, and tortuosity index (ε and hemodynamic loads was observed, and it could be used as a potential predictor of AAA arterial wall rupture and potential ILT formation.

  6. Intraoral gothic arch tracing.

    Science.gov (United States)

    Rubel, Barry; Hill, Edward E

    2011-01-01

    In order to create optimum esthetics, function and phonetics in complete denture fabrication, it is necessary to record accurate maxillo-mandibular determinants of occlusion. This requires clinical skill to establish an accurate, verifiable and reproducible vertical dimension of occlusion (VDO) and centric relation (CR). Correct vertical relation depends upon a consideration of several factors, including muscle tone, inter-dental arch space and parallelism of the ridges. Any errors made while taking maxillo-mandibular jaw relation records will result in dentures that are uncomfortable and, possibly, unwearable. The application of a tracing mechanism such as the Gothic arch tracer (a central bearing device) is a demonstrable method of determining centric relation. Intraoral Gothic arch tracers provide the advantage of capturing VDO and CR in an easy-to-use technique for practitioners. Intraoral tracing (Gothic arch tracing) is a preferred method of obtaining consistent positions of the mandible in motion (retrusive, protrusive and lateral) at a comfortable VDO.

  7. Determining rural risk for aneurysmal subarachnoid hemorrhages: A structural equation modeling approach.

    Science.gov (United States)

    Nichols, Linda Jayne; Gall, Seana; Stirling, Christine

    2016-01-01

    An aneurysmal subarachnoid hemorrhage (aSAH) carries a high disability burden. The true impact of rurality as a predictor of outcome severity is unknown. Our aim is to clarify the relationship between the proposed explanations of regional and rural health disparities linked to severity of outcome following an aSAH. An initial literature search identified limited data directly linking geographical location, rurality, rural vulnerability, and aSAH. A further search noting parallels with ischemic stroke and acute myocardial infarct literature presented a number of diverse and interrelated predictors. This a priori knowledge informed the development of a conceptual framework that proposes the relationship between rurality and severity of outcome following an aSAH utilizing structural equation modeling. The presented conceptual framework explores a number of system, environmental, and modifiable risk factors. Socioeconomic characteristics, modifiable risk factors, and timely treatment that were identified as predictors of severity of outcome following an aSAH and within each of these defined predictors a number of contributing specific individual predictors are proposed. There are considerable gaps in the current knowledge pertaining to the impact of rurality on the severity of outcome following an aSAH. Absent from the literature is any investigation of the cumulative impact and multiplicity of risk factors associated with rurality. The proposed conceptual framework hypothesizes a number of relationships between both individual level and system level predictors, acknowledging that intervening predictors may mediate the effect of one variable on another.

  8. Determining rural risk for aneurysmal subarachnoid hemorrhages: A structural equation modeling approach

    Science.gov (United States)

    Nichols, Linda Jayne; Gall, Seana; Stirling, Christine

    2016-01-01

    An aneurysmal subarachnoid hemorrhage (aSAH) carries a high disability burden. The true impact of rurality as a predictor of outcome severity is unknown. Our aim is to clarify the relationship between the proposed explanations of regional and rural health disparities linked to severity of outcome following an aSAH. An initial literature search identified limited data directly linking geographical location, rurality, rural vulnerability, and aSAH. A further search noting parallels with ischemic stroke and acute myocardial infarct literature presented a number of diverse and interrelated predictors. This a priori knowledge informed the development of a conceptual framework that proposes the relationship between rurality and severity of outcome following an aSAH utilizing structural equation modeling. The presented conceptual framework explores a number of system, environmental, and modifiable risk factors. Socioeconomic characteristics, modifiable risk factors, and timely treatment that were identified as predictors of severity of outcome following an aSAH and within each of these defined predictors a number of contributing specific individual predictors are proposed. There are considerable gaps in the current knowledge pertaining to the impact of rurality on the severity of outcome following an aSAH. Absent from the literature is any investigation of the cumulative impact and multiplicity of risk factors associated with rurality. The proposed conceptual framework hypothesizes a number of relationships between both individual level and system level predictors, acknowledging that intervening predictors may mediate the effect of one variable on another. PMID:27695237

  9. Flow investigation in sidewall aneurysm model using a novel PIV multi-time-lag method

    Science.gov (United States)

    Bouillot, Pierre; Brina, Olivier; Ouared, Rafik; Lovblad, Karl-Olof; Mendes Pereira, Vitor; Farhat, Mohamed

    2013-11-01

    The intracranial aneurysm (IA) lesion is one of the main causes of intracranial hemorrhage in productive population. It is well known that the hemodynamic factors have large impact on both the IAs rupture and treatment efficacy based on flow diverter stents. Precise experimental investigations of blood flow in IAs using particle imaging velocimetry (PIV) are therefore strongly required in order to validate clinical treatments based on computational and clinical flow assessment tools. Due to the large variations of flow velocities in IAs, a single PIV measurement with a unique time lag between two consecutive images cannot provide a good level of precision in all the measured volume. In this work, we implement an error analysis based on several PIV measurements with different time lags to ensure an optimal precision in the entire measurement volume. This PIV multi-time-lag method is applied on a sidewall IA model to investigate the effect of the inflow pulsatility. By comparing the flow patterns resulting from steady and unsteady inflows we point out important differences which could be involved in the IAs evolution. In particular, the blood transfer in the IA and the vortical structure are significantly modified when increasing the pulsatility compared to quasi-steady conditions.

  10. Evolution Characteristic Analysis of Pressure-arch of a Double-arch Tunnel in Water-rich Strata

    Directory of Open Access Journals (Sweden)

    C. L. Li

    2016-03-01

    Full Text Available It is of importance to analyze the morphological characterization, the evolution process and the skewed effect of pressure-arch of a double-arch tunnel in the water-rich strata. Taking a buried depth 80 m double-arch tunnel as an example, a computational model of the double-arch tunnel was built by using FLAC3D technique. Then considering some aspects including groundwater conditions, tunnel depth, construction sequences and permeability coefficients, the coupling effect of stress field and seepage field in the pressure-arch of the double-arch tunnel was analyzed. The results show that the thickness of the pressure-arch induced by step-by-step excavation and display a step-descent skewed distribution from the left to the right of the double-arch tunnel. The permeability coefficient has a significant influence on the shape and the skewed effect of the pressure arch. The excavation of the bench method has a better arching condition than that of the expanding method. The abtained results provide a basic reference for the rock reinforcement design and safety construction of double-arch tunnels in the water-rich strata.

  11. Aortic coarctation, aneurysm, and ventricular dysfunction in an asymptomatic infant.

    Science.gov (United States)

    García, Ana I; Aguilar, Juan M; García, Enrique

    2016-06-01

    Aortic arch coarctation with post-coarctation aneurysm is rare in infants. We present the case of an asymptomatic 3-month-old infant with severe left ventricular dysfunction in this setting. The patient underwent surgical repair, and the left ventricular ejection fraction improved to recovery the 4th post-operative month.

  12. Day of the week effect in paper submission/acceptance/rejection to/in/by peer review journals. II. An ARCH econometric-like modeling

    Science.gov (United States)

    Ausloos, Marcel; Nedic, Olgica; Dekanski, Aleksandar; Mrowinski, Maciej J.; Fronczak, Piotr; Fronczak, Agata

    2017-02-01

    This paper aims at providing a statistical model for the preferred behavior of authors submitting a paper to a scientific journal. The electronic submission of (about 600) papers to the Journal of the Serbian Chemical Society has been recorded for every day from Jan. 01, 2013 till Dec. 31, 2014, together with the acceptance or rejection paper fate. Seasonal effects and editor roles (through desk rejection and subfield editors) are examined. An ARCH-like econometric model is derived stressing the main determinants of the favorite day-of-week process.

  13. Day of the week effect in paper submission/acceptance/rejection to/in/by peer review journals. II. An ARCH econometric-like modeling

    CERN Document Server

    Ausloos, Marcel; Dekanski, Aleksandar; Mrowinski, Maciej J; Fronczak, Piotr; Fronczak, Agata

    2016-01-01

    This paper aims at providing a statistical model for the preferred behavior of authors submitting a paper to a scientific journal. The electronic submission of (about 600) papers to the Journal of the Serbian Chemical Society has been recorded for every day from Jan. 01, 2013 till Dec. 31, 2014, together with the acceptance or rejection paper fate. Seasonal effects and editor roles (through desk rejection and subfield editors) are examined. An ARCH-like econometric model is derived stressing the main determinants of the favorite day-of-week process.

  14. Aortic aneurysm repair - endovascular

    Science.gov (United States)

    EVAR; Endovascular aneurysm repair - aorta; AAA repair - endovascular; Repair - aortic aneurysm - endovascular ... Endovascular aortic repair is done because your aneurysm is very large, growing quickly, or is leaking or bleeding. You may have ...

  15. Aneurysm in the brain

    Science.gov (United States)

    ... aneurysms Medical problems such as polycystic kidney disease , coarctation of the aorta , and endocarditis High blood pressure, ... Read More Aneurysm Brain aneurysm repair Brain surgery Coarctation of the aorta Endovascular embolization Epilepsy - overview Incidence ...

  16. Advances in saccular aneurysm models in the necks of rabbits%兔颈囊状动脉瘤动物模型的研究进展

    Institute of Scientific and Technical Information of China (English)

    黄乾亮; 李美华

    2009-01-01

    Intracranial aneurysm is one of the common diseases in neurosurgery. The mortality and disability are higher after its rupture. Creating a good aneurysm model is the basis in the study of the etiology and pathophysiological mechanisms of intracranial aneurysm. Rabbits have been widely used as aneurysm models by the domestic and foreign researchers. This article mainly presents the methods of how to create aneurysm models in the necks of rabbits and their application prospects.%颅内动脉瘤是神经外科常见疾病之一,其破裂出血后的病死率和致残率较高.建立良好的动脉瘤动物模型是研究颅内动脉瘤病因学和病理生理学机制的基础.兔已被国内外学者广泛用作动脉瘤模型动物.文章主要介绍兔颈部动脉瘤模型的制作方法及应用前景.

  17. Endovascular repair for abdominal aortic aneurysm followed by type B dissection.

    Science.gov (United States)

    Shingaki, Masami; Kato, Masaaki; Motoki, Manabu; Kubo, Yoji; Isaji, Toshihiko; Okubo, Nobukazu

    2016-10-01

    An 86-year-old man with an abdominal aortic aneurysm was diagnosed with type B aortic dissection accompanied by a patent false lumen that started at the distal arch of the thoracic aorta and terminated at the left common iliac artery. Meticulous preoperative assessment detected 3 large intimal tears in the descending aorta, abdominal aortic aneurysm, and left common iliac artery. We performed single-stage thoracic and abdominal endovascular aneurysm repair and concomitant axillary-axillary bypass. The abdominal aortic aneurysm with type B aortic dissection was successfully treated using a single-stage endovascular stent graft, without any complications due to the careful preoperative examinations.

  18. [Three-dimensional modelling of thoracic aortic aneurysm. A case report].

    Science.gov (United States)

    Carmi, D; Zegdi, R; Grebe, R; Fabiani, J N

    2001-04-01

    The anatomical forms of aneurysms are sometimes complex. Three-dimensional modelisation may be valuable in understanding the configuration and spatial orientation on one hand and also help in therapeutic decision making on the other. Two types of modelisation are reported with details of their methods and their respective values.

  19. An integrated fluid-chemical model towards modeling the formation of intra-luminal thrombus in abdominal aortic aneurysms

    Directory of Open Access Journals (Sweden)

    Jacopo eBiasetti

    2012-07-01

    Full Text Available Abdominal Aortic Aneurysms (AAAs are frequently characterized by the presenceof an Intra-Luminal Thrombus (ILT known to influence biochemically and biomechanicallytheir evolution. ILT progression mechanism is still unclear and little is known regardingthe impact on this mechanism of the chemical species transported by blood flow.Chemical agonists and antagonists of platelets activation, aggregation, and adhesion andthe proteins involved in the coagulation cascade (CC may play an important role in ILTdevelopment. Starting from this assumption, the evolution of chemical species involvedin the CC, their relation to coherent vortical structures (VSs and their possible effect onILT evolution have been studied. To this end a fluido-chemical model that simulates theCC through a series of convection-diffusion-reaction (CDR equations has been developed.The model involves plasma-phase and surface bound enzymes and zymogens, and includesboth plasma-phase and membrane-phase reactions. Blood is modeled as a non-Newtonianincompressible fluid. VSs convect thrombin in the domain and lead to the high concentration observed in the distal portion of the AAA. This finding is in line with the clinicalobservations showing that the thickest ILT is usually seen in the distal AAA region. Theproposed model, due to its ability to couple the fluid and chemical domains, provides anintegrated mechanochemical picture that potentially could help unveil mechanisms of ILTformation and development.

  20. 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.

  1. Bentall术联合全弓置换及支架象鼻手术治疗危重Debakey Ⅰ型主动脉夹层动脉瘤%Bentall operation combined with total arch replacement and stented elephant trunk implantation for serious Debakey I aortic dissecting aneurysm

    Institute of Scientific and Technical Information of China (English)

    谷天祥; 王春; 张玉海; 修宗谊; 房勤; 喻磊; 师恩祎

    2008-01-01

    Objective To summarize the clinical experience of Bentall operation combined with total arch replacement and stented elephant trunk implantation for serious Debakey I aortic dissecting aneurysrm Methods Twelve patients with serious Debakey I aortic dissecting aneurysm underwent surgical treatment from January 2005 to December 2007.There were 10 male and 2 female with the mean age of (40.1±9.5)years old.There were acute aortic dissection in 9 cases,chronic aortic dissection in 3 cases.The inner diameter of aorta was(5.3±1.8)cm. There were Mafan syndrome in 4 cases,aortic regurgitation in all cases,severely persistent chest pain in 9 eases,acute left heart failure in 8 cases,and cardiac tamponade in 4 cases.Bentall operations eombined with total arch replacement and stented elephant trunk implantation were performed by using deep hypothermic circulatory arrest and antegrade selective cerebral perfusion in all cases.Results Urgent surgery underwent in 9 cases.The mean interval between the onset of aortic dissection and the accomplishment of surgery wag(41.0±15.9)hours.Cardiopulmonary bypass time was(191±26)min,average cross clamp time was(134±31)min,and average deep hypothermie circulatory arrest time was(50.0±14.5)min One patient died in hospital.The time stayed in ICU was 3 to 27 d Mental disorder in 6 eases,hemiparalysis in 1 case,amputation in 1 case,hemorrhage of anastomosis in 1 ease.hemorrhage of alimentary tract in 1 cage,and pleural effusion in 4 cases were recorded.Eleven cases were followed-up for 8 weeks to 36 months.There were no bending of the stents and no obstruction in the vascular prosthesis.No re-operation was needed.One case died 6 months postoperatively.Conclusion Bentall operation combined with total arch replacement and stented elephant trunk implantation is safe and effective for serious Debakey I aortic dissecting aneurysm,while good organs protection and consummate cardiopulmonary bypass were taken.%目的 总结Bentall术同期全弓

  2. Antibody directs properdin-dependent activation of the complement alternative pathway in a mouse model of abdominal aortic aneurysm.

    Science.gov (United States)

    Zhou, Hui-Fang; Yan, Huimin; Stover, Cordula M; Fernandez, Tamara Montes; Rodriguez de Cordoba, Santiago; Song, Wen-Chao; Wu, Xiaobo; Thompson, Robert W; Schwaeble, Wilhelm J; Atkinson, John P; Hourcade, Dennis E; Pham, Christine T N

    2012-02-14

    Abdominal aortic aneurysm (AAA) is a complex inflammatory vascular disease. There are currently limited treatment options for AAA when surgery is inapplicable. Therefore, insights into molecular mechanisms underlying AAA pathogenesis may reveal therapeutic targets that could be manipulated pharmacologically or biologically to halt disease progression. Using an elastase-induced AAA mouse model, we previously established that the complement alternative pathway (AP) plays a critical role in the development of AAA. However, the mechanism by which complement AP is initiated remains undefined. The complement protein properdin, traditionally viewed as a positive regulator of the AP, may also initiate complement activation by binding directly to target surfaces. In this study, we sought to determine whether properdin serves as a focal point for the initiation of the AP complement activation in AAA. Using a properdin loss of function mutation in mice and a mutant form of the complement factor B protein that produces a stable, properdin-free AP C3 convertase, we show that properdin is required for the development of elastase-induced AAA in its primary role as a convertase stabilizer. Unexpectedly, we find that, in AAA, natural IgG antibodies direct AP-mediated complement activation. The absence of IgG abrogates C3 deposition in elastase-perfused aortic wall and protects animals from AAA development. We also determine that blockade of properdin activity prevents aneurysm formation. These results indicate that an innate immune response to self-antigens activates the complement system and initiates the inflammatory cascade in AAA. Moreover, the study suggests that properdin-targeting strategies may halt aneurysmal growth.

  3. QueryArch3D: Querying and Visualising 3D Models of a Maya Archaeological Site in a Web-Based Interface

    Directory of Open Access Journals (Sweden)

    Giorgio Agugiaro

    2011-12-01

    Full Text Available Constant improvements in the field of surveying, computing and distribution of digital-content are reshaping the way Cultural Heritage can be digitised and virtually accessed, even remotely via web. A traditional 2D approach for data access, exploration, retrieval and exploration may generally suffice, however more complex analyses concerning spatial and temporal features require 3D tools, which, in some cases, have not yet been implemented or are not yet generally commercially available. Efficient organisation and integration strategies applicable to the wide array of heterogeneous data in the field of Cultural Heritage represent a hot research topic nowadays. This article presents a visualisation and query tool (QueryArch3D conceived to deal with multi-resolution 3D models. Geometric data are organised in successive levels of detail (LoD, provided with geometric and semantic hierarchies and enriched with attributes coming from external data sources. The visualisation and query front-end enables the 3D navigation of the models in a virtual environment, as well as the interaction with the objects by means of queries based on attributes or on geometries. The tool can be used as a standalone application, or served through the web. The characteristics of the research work, along with some implementation issues and the developed QueryArch3D tool will be discussed and presented.

  4. An Electrostatically Actuated MEMS Arch Band-Pass Filter

    Directory of Open Access Journals (Sweden)

    Hassen M. Ouakad

    2013-01-01

    Full Text Available This work presents an investigation of the dynamics of micromachined arches resonators and their potential to be utilized as band-pass filters. The arches are actuated by a DC electrostatic load superimposed to an AC harmonic load. The dynamic response of the arch is studied analytically using a Galerkin-based reduced-order model when excited near its fundamental and third natural frequencies. Several simulation results are presented demonstrating interesting jumps and snap-through behavior of the arches and their attractive features for uses as band-pass filters, such as their sharp roll-off from pass bands to stop bands and their flat response.

  5. Residual Cusum Test for Parameters Change in ARCH Errors Models with Deterministic Trend%带趋势项的ARCH误差模型参数变化的残量检验

    Institute of Scientific and Technical Information of China (English)

    金浩; 田铮

    2009-01-01

    This paper analyzes the problem of testing for parameters change in ARCH errors models with deterministic trend based on residual cusum test. It is shown that the asymptotically limiting distribution of the residual cusum test statistic is still the sup of a standard Brownian bridge under null hypothesis. In order to check this, we carry out a Monte Carlo simulation and examine the return of IBM data. The results from both simulation and real data analysis support our claim. We also can explain this phenomenon from a theoretical viewpoint that the variance in ARCH model in mainly determined by its parameters.

  6. Tubular Steel Arch Stabilized by Textile Membranes

    Directory of Open Access Journals (Sweden)

    Ondrej Svoboda

    2016-10-01

    Full Text Available Tubular steel arch supporting textile membrane roofing is investigated experimentally and numerically. The stabilization effects of the textile membrane on in-plane and out-of-plane behavior of the arch is of primary interest. First a model of a large membrane structure tested in laboratory is described. Prestressed membranes of PVC coated polyester fabric Ferrari® Précontraint 702S were used as a currently standard and excellent material. The test arrangement, loading and resulting load/deflection values are presented. The supporting structure consisted of two steel arch tubes, outer at edge of the membrane and inner supporting interior of the membrane roofing. The stability and strength behavior of the inner tube under both symmetrical and asymmetrical loading was monitored and is shown in some details. Second the SOFiSTiK software was employed to analyze the structural behavior in 3D, using geometrically nonlinear analysis with imperfections (GNIA. The numerical analysis, FE mesh sensitivity, the membrane prestressing and common boundary conditions are validated by test results. Finally a parametrical study concerning stability of mid arch with various geometries in a membrane structure with several supporting arches is presented, with recommendations for a practical design.

  7. [Popliteal aneurysms].

    Science.gov (United States)

    Vaquero Morillo, F; Zorita Calvo, A; Fernández-Samos Gutiérrez, R; García Vázquez, J; Ortega Martín, J M; Fernández Morán, C

    1992-01-01

    We presented the review of 22 cases of popliteal aneurysms with a follow-time of three years. One case was a woman and 5 cases were bilaterals. The most part of cases begun as a latter acute ischemia. Sixteen cases were treated surgically, with a null rate of mortality, 2 amputations, 4 cases of residual intermittent claudication and 10 no-symptomatic patients, with present distal pulses. Etiology, clinical presentation, diagnosis, technics and results are presented and a comparison with other authors is made. Our experience support an interventionist attitude in cases of elderly nonsymptomatic patients, performed by internal way and saphenous vein substitution.

  8. The ARCHES Project

    Science.gov (United States)

    Motch, C.; Arches Consortium

    2015-09-01

    The Astronomical Resource Cross-matching for High Energy Studies (ARCHES) project is a FP7-Space funded programme started in 2013 and involving the Observatoire Astronomique de Strasbourg including the CDS (France), the Leibniz- Institut für Astrophysik Potsdam (Germany), the University of Leicester (UK), the Universidad de Cantabria (IFCA, Spain) and the Instituto Nacional de Tecnica Aeroespacial (Spain). ARCHES will provide the international astronomical community with well-characterised multi-wavelength data in the form of spectral energy distributions (SEDs) for large samples of objects extracted from the 3XMM X-ray catalogue of serendipitous sources. The project develops new tools implementing fully probabilistic simultaneous cross-correlation of several catalogues and a multi-wavelength finder for clusters of galaxies. SEDs are based on an enhanced version of the 3XMM catalogue and on a careful selection of the most relevant multi-wavelength archival catalogues. In order to ensure the largest audience, SEDs will be distributed to the international community through CDS services and through the Virtual Observatory. These enhanced resources are tested in the framework of several science cases. More information may be found at http://www.arches-fp7.eu/

  9. How to Perfuse: Concepts of Cerebral Protection during Arch Replacement

    Directory of Open Access Journals (Sweden)

    Andreas Habertheuer

    2015-01-01

    Full Text Available Arch surgery remains undoubtedly among the most technically and strategically challenging endeavors in cardiovascular surgery. Surgical interventions of thoracic aneurysms involving the aortic arch require complete circulatory arrest in deep hypothermia (DHCA or elaborate cerebral perfusion strategies with varying degrees of hypothermia to achieve satisfactory protection of the brain from ischemic insults, that is, unilateral/bilateral antegrade cerebral perfusion (ACP and retrograde cerebral perfusion (RCP. Despite sophisticated and increasingly individualized surgical approaches for complex aortic pathologies, there remains a lack of consensus regarding the optimal method of cerebral protection and circulatory management during the time of arch exclusion. Many recent studies argue in favor of ACP with various degrees of hypothermic arrest during arch reconstruction and its advantages have been widely demonstrated. In fact ACP with more moderate degrees of hypothermia represents a paradigm shift in the cardiac surgery community and is widely adopted as an emergent strategy; however, many centers continue to report good results using other perfusion strategies. Amidst this important discussion we review currently available surgical strategies of cerebral protection management and compare the results of recent European multicenter and single-center data.

  10. How to Perfuse: Concepts of Cerebral Protection during Arch Replacement

    Science.gov (United States)

    Habertheuer, Andreas; Wiedemann, Dominik; Kocher, Alfred; Laufer, Guenther; Vallabhajosyula, Prashanth

    2015-01-01

    Arch surgery remains undoubtedly among the most technically and strategically challenging endeavors in cardiovascular surgery. Surgical interventions of thoracic aneurysms involving the aortic arch require complete circulatory arrest in deep hypothermia (DHCA) or elaborate cerebral perfusion strategies with varying degrees of hypothermia to achieve satisfactory protection of the brain from ischemic insults, that is, unilateral/bilateral antegrade cerebral perfusion (ACP) and retrograde cerebral perfusion (RCP). Despite sophisticated and increasingly individualized surgical approaches for complex aortic pathologies, there remains a lack of consensus regarding the optimal method of cerebral protection and circulatory management during the time of arch exclusion. Many recent studies argue in favor of ACP with various degrees of hypothermic arrest during arch reconstruction and its advantages have been widely demonstrated. In fact ACP with more moderate degrees of hypothermia represents a paradigm shift in the cardiac surgery community and is widely adopted as an emergent strategy; however, many centers continue to report good results using other perfusion strategies. Amidst this important discussion we review currently available surgical strategies of cerebral protection management and compare the results of recent European multicenter and single-center data. PMID:26713319

  11. Reproducibility of haemodynamical simulations in a subject-specific stented aneurysm model--a report on the Virtual Intracranial Stenting Challenge 2007.

    Science.gov (United States)

    Radaelli, A G; Augsburger, L; Cebral, J R; Ohta, M; Rüfenacht, D A; Balossino, R; Benndorf, G; Hose, D R; Marzo, A; Metcalfe, R; Mortier, P; Mut, F; Reymond, P; Socci, L; Verhegghe, B; Frangi, A F

    2008-07-19

    This paper presents the results of the Virtual Intracranial Stenting Challenge (VISC) 2007, an international initiative whose aim was to establish the reproducibility of state-of-the-art haemodynamical simulation techniques in subject-specific stented models of intracranial aneurysms (IAs). IAs are pathological dilatations of the cerebral artery walls, which are associated with high mortality and morbidity rates due to subarachnoid haemorrhage following rupture. The deployment of a stent as flow diverter has recently been indicated as a promising treatment option, which has the potential to protect the aneurysm by reducing the action of haemodynamical forces and facilitating aneurysm thrombosis. The direct assessment of changes in aneurysm haemodynamics after stent deployment is hampered by limitations in existing imaging techniques and currently requires resorting to numerical simulations. Numerical simulations also have the potential to assist in the personalized selection of an optimal stent design prior to intervention. However, from the current literature it is difficult to assess the level of technological advancement and the reproducibility of haemodynamical predictions in stented patient-specific models. The VISC 2007 initiative engaged in the development of a multicentre-controlled benchmark to analyse differences induced by diverse grid generation and computational fluid dynamics (CFD) technologies. The challenge also represented an opportunity to provide a survey of available technologies currently adopted by international teams from both academic and industrial institutions for constructing computational models of stented aneurysms. The results demonstrate the ability of current strategies in consistently quantifying the performance of three commercial intracranial stents, and contribute to reinforce the confidence in haemodynamical simulation, thus taking a step forward towards the introduction of simulation tools to support diagnostics and

  12. The Analysis of Domestic Oil Price Fluctuation Based on ARCH Models%基于ARCH类模型的国内油价波动分析

    Institute of Scientific and Technical Information of China (English)

    潘慧峰; 张金水

    2005-01-01

    The ARCH type models are applied on the weekly data of crude oil return from January 1997 to November 2003 to examine the features of volatility in China market. Our findings indicate that there exists significant conditional heteroskedasticity but with low persistence in the return of crude oil. The leverage effect in oil market is different from the one in the stock market, which shows that upward movements in the price of crude oil are followed by higher volatilities than downward movements of the same magnitude. Based on this, this paper analyzes the cause of the leverage effect in crude oil market from the angel of nonrenewable resources and discusses the countermeasures to deal with the volatility in oil price in terms of the situation of China.

  13. Analysis and Comparison of 2-D Hemodynamic Numerical Simulation of Elastic Aneurysm and Rigid Aneurysm

    Science.gov (United States)

    Zhao, J. W.; Ding, G. H.; Yin, W. Y.; Yang, X. J.; Shi, W. C.; Zhang, X. L.

    The objective of this study is to investigate the effect of hemodynamic parameters on the formation, growth and rupture of an aneurysm. Our simulation of the elastic and rigid aneurysm is based on a DSA or other clinic image. The simulatied results are that there are great differences in the distribution of velocity magnitude at some sections which are predicted by the two models. For the elastic wall model, the distribution of velocity magnitude of one outlet is obviously off-center, which influences the distribution of wall shear stress (WSS) and exchange of substance through the vessel wall. The currents of the distributions of WSS along the wall of aneurysm for the two models are similar. But there are obvious differences between the two models in the values especially at the neck of aneurysm. This study demonstrates obviously that the elastic wall model suits the simulation for growth and rupture of an aneurysm better.

  14. Therapeutics Targeting Drivers of Thoracic Aortic Aneurysms and Acute Aortic Dissections: Insights from Predisposing Genes and Mouse Models.

    Science.gov (United States)

    Milewicz, Dianna M; Prakash, Siddharth K; Ramirez, Francesco

    2017-01-14

    Thoracic aortic diseases, including aneurysms and dissections of the thoracic aorta, are a major cause of morbidity and mortality. Risk factors for thoracic aortic disease include increased hemodynamic forces on the ascending aorta, typically due to poorly controlled hypertension, and heritable genetic variants. The altered genes predisposing to thoracic aortic disease either disrupt smooth muscle cell (SMC) contraction or adherence to an impaired extracellular matrix, or decrease canonical transforming growth factor beta (TGF-β) signaling. Paradoxically, TGF-β hyperactivity has been postulated to be the primary driver for the disease. More recently, it has been proposed that the response of aortic SMCs to the hemodynamic load on a structurally defective aorta is the primary driver of thoracic aortic disease, and that TGF-β overactivity in diseased aortas is a secondary, unproductive response to restore tissue function. The engineering of mouse models of inherited aortopathies has identified potential therapeutic agents to prevent thoracic aortic disease.

  15. The ARCHES project

    CERN Document Server

    Motch, C; Genova, F; Esteban, F Jiménez-; López, M; Michel, L; Mingo, B; Mints, A; Gómez-Morán, A Nebot; Pineau, F -X; Rosen, S; Sanchez, E; Schwope, A; Solano, E; Watson, M

    2016-01-01

    ARCHES (Astronomical Resource Cross-matching for High Energy Studies) is a FP7-Space funded project whose aim is to provide the international astronomical community with well-characterised multi-wavelength data in the form of spectral energy distributions (SEDs) for large samples of objects extracted from the 3XMM DR5 X-ray catalogue of serendipitous sources. The project has developed new tools implementing fully probabilistic simultaneous cross-correlation of several catalogues for unresolved sources and a multi-wavelength finder for clusters of galaxies for extended sources. These enhanced resources have been tested in the framework of several science cases.

  16. Double arch mirror study

    Science.gov (United States)

    Vukobratovich, D.; Hillman, D.

    1983-01-01

    The development of a method of mounting light weight glass mirrors for astronomical telescopes compatible with the goals of the Shuttle Infrared Telescope Facility (SIRTF) was investigated. A 20 in. diameter double arch lightweight mirror previously fabricated was modified to use a new mount configuration. This mount concept was developed and fabricated. The mounting concept of the double mounting mirror is outlined. The modifications made to the mirror, fabrication of the mirror mount, and room temperature testing of the mirror and mount and the extension of the mirror and mount concept to a full size (40 in. diameter) primary mirror for SIRTF are discussed.

  17. Outcomes of single-stage total arch replacement via clamshell incision

    Directory of Open Access Journals (Sweden)

    Ishizaka Toru

    2011-09-01

    Full Text Available Abstract Background Treatment of complex aortic pathologies involving the transverse arch with extensive involvement of the descending aorta remains a surgical challenge. Since clamshell incision provides superior exposure of the entire thoracic aorta, we evaluated the use of this technique for single-stage total arch replacement by arch vessel reconstruction. Methods The arch-first technique combined with clamshell incision was used in 38 cases of aneurysm and aortic disease in 2008 and 2009. Extensive total arch replacement was used with clamshell incision for reconstruction of arch vessels under deep hypothermic circulatory arrest. Results Overall 30-day mortality was 13%. The mean operating time was approximately 8 hours. Deep hypothermia resulted in mean CPB time exceeding 4.5 hours and mean duration of circulatory arrest was 25 minutes. The overall postoperative temporary and permanent neurologic dysfunction rates were 3% and 3% for elective and 3% and 0% for emergency surgery, respectively. All patients except the five who died in hospital were discharged without nursing care after an average post-operative hospital stay of 35 days. Conclusions The arch-first technique, combined with clamshell incision, provides expeditious replacement of the thoracic aorta with an acceptable duration of hypothermic circulatory arrest and minimizes the risk of retrograde atheroembolism by using antegrade perfusion.

  18. Abdominal aortic aneurysm

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000162.htm Abdominal aortic aneurysm To use the sharing features on this page, ... blood to the abdomen, pelvis, and legs. An abdominal aortic aneurysm occurs when an area of the aorta becomes ...

  19. Paediatric intracranial aneurysms

    Directory of Open Access Journals (Sweden)

    A A Wani

    2006-01-01

    Full Text Available Intracranial aneurysms in childhood account for 1-2% of intracranial aneurysms.[1],[2] These aneurysms have unique characteristics that make them different from those in adults. These differences are evident in their epidemiology, location, clinical spectrum, association with trauma and infection, complications and outcome.

  20. Unruptured intracranial aneurysms

    NARCIS (Netherlands)

    Backes, Daan

    2016-01-01

    Rupture of an intracranial aneurysm results in aneurysmal subarachnoid hemorrhage (SAH), a subtype of stroke with an incidence of 9 per 100,000 person-years and a case-fatality around 35%. In order to prevent SAH, patients with unruptured intracranial aneurysms can be treated by neurosurgical or end

  1. Stroke due to a fusiform aneurysm of the cervical vertebral artery: case report

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, S. [Department of Neurosurgery, Kyushu University Hospital, Fukuoka (Japan)]|[Department of Neurosurgery, Kyushu University Hospital 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-82 (Japan); Inoue, T. [Department of Neurosurgery, Clinical Research Institute, National Kyushu Medical Center, Fukuoka (Japan); Haga, S.; Nishio, S.; Fukui, M. [Department of Neurosurgery, Kyushu University Hospital, Fukuoka (Japan); Kono, S. [First Department of Pathology, Kyushu University Hospital, Fukuoka (Japan); Mizushima, A. [Department of Radiology, Kyushu University Hospital, Fukuoka (Japan)

    1998-01-01

    Aneurysms of the cervical vertebral artery (VA) are uncommon; they are often caused by trauma or spontaneous dissection. A fusiform aneurysm without evidence of atherosclerosis or dissection has not been reported previously. A 46-year-old man presented with a pontine infarct. Imaging revealed a fusiform aneurysm of the left VA at the C5-6 level, with occlusion of the basilar artery. Associated minor anomalies included fusion of the vertebral bodies of C5 and C6, cervical rib and platybasia. The left VA arose directly from the aortic arch and entered the transverse foramen at the C4 level. Hyperextension and left lateral flexion of the neck caused kinking of the VA proximal to the aneurysm. Turbulent flow in the aneurysm lumen was noted on angiography. (orig.) With 4 figs., 10 refs.

  2. Coronary artery aneurysms

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-04-01

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

  3. Pediatric isolated bilateral iliac aneurysm.

    Science.gov (United States)

    Chithra, R; Sundar, R Ajai; Velladuraichi, B; Sritharan, N; Amalorpavanathan, J; Vidyasagaran, T

    2013-07-01

    Aneurysms are rare in children. Isolated iliac artery aneurysms are very rare, especially bilateral aneurysms. Pediatric aneurysms are usually secondary to connective tissue disorders, arteritis, or mycotic causes. We present a case of a 3-year-old child with bilateral idiopathic common iliac aneurysms that were successfully repaired with autogenous vein grafts.

  4. Aortic aneurysm and diverticulum of Kommerell: a dreadful concomitance

    Directory of Open Access Journals (Sweden)

    Fernando Peixoto Ferraz de Campos

    2012-12-01

    Full Text Available First described in 1936, the diverticulum of Kommerell (DOK is a dilatation of the proximal segment of an aberrant subclavian artery. Appearing more frequently in the left-sided aortic arch, the aberrant right subclavian artery passes behind the esophagus toward the right arm, causing symptoms in the minority of cases. Diagnosis is generally incidental with this pattern. When symptomatic, dysphagia, respiratory symptoms, hoarseness, chest pain, and upper limb ischemia are the most common complaints. Although debatable, the origin of DOK is accepted as being degenerative or congenital. The degenerative condition is normally associated with atherosclerosis and occurs more frequently after the age of 50 years with no gender predominance. Complications may be life threatening and are more commonly related to the diverticulum aneurysm or when associated with aortic diseases such as aneurysms or dissection. The authors present a case of a 67-year-old male with a history of acute chest pain, neurological disturbances, and hypertensive crisis. The diagnostic workup revealed an aortic arch aneurysm with intramural hematoma and a diverticulum aneurysm of Kommerell. Treatment was conservative at first. The patient presented a satisfactory outcome and was referred to an outpatient clinic for follow up and further therapeutic consolidation.

  5. Lipolysis of emulsion models of triglyceride-rich lipoproteins is altered in male patients with abdominal aorta aneurysm

    Directory of Open Access Journals (Sweden)

    J.J. Hosni

    2007-03-01

    Full Text Available Disorders of the lipid metabolism may play a role in the genesis of abdominal aorta aneurysm. The present study examined the intravascular catabolism of chylomicrons, the lipoproteins that carry the dietary lipids absorbed by the intestine in the circulation in patients with abdominal aorta aneurysm. Thirteen male patients (72 ± 5 years with abdominal aorta aneurysm with normal plasma lipid profile and 13 healthy male control subjects (73 ± 5 years participated in the study. The method of chylomicron-like emulsions was used to evaluate this metabolism. The emulsion labeled with 14C-cholesteryl oleate and ³H-triolein was injected intravenously in both groups. Blood samples were taken at regular intervals over 60 min to determine the decay curves. The fractional clearance rate (FCR of the radioactive labels was calculated by compartmental analysis. The FCR of the emulsion with ³H-triolein was smaller in the aortic aneurysm patients than in controls (0.025 ± 0.017 vs 0.039 ± 0.019 min-1; P < 0.05, but the FCR of14C-cholesteryl oleate of both groups did not differ. In conclusion, as indicated by the triglyceride FCR, chylomicron lipolysis is diminished in male patients with aortic aneurysm, whereas the remnant removal which is traced by the cholesteryl oleate FCR is not altered. The results suggest that defects in the chylomicron metabolism may represent a risk factor for development of abdominal aortic aneurysm.

  6. Description of dental arch form using the Fourier series.

    Science.gov (United States)

    Valenzuela, A Patricia; Pardo, Marco A; Yezioro, Salomon

    2002-01-01

    The aim of this study was to describe the form of the human superior dental arch using Fourier transformations. Forty models made in dental stone from impressions of the maxillary dental arch were used to obtain the reference data, which were expressed in Cartesian coordinates, from the mesovestibular cuspid vertices of molar teeth, vestibular cuspid of premolars, and incisal edge. Fourth-grade equations and Fourier series were calculated from these data. The results indicate that Fourier series more precisely express the form and size of different dental arches, with mixed or permanent dentition, than fourth-grade equations. Details of the mathematical procedure and the precision obtained were provided.

  7. Epidermal growth factor receptor inhibitor protects against abdominal aortic aneurysm in a mouse model.

    Science.gov (United States)

    Obama, Takashi; Tsuji, Toshiyuki; Kobayashi, Tomonori; Fukuda, Yamato; Takayanagi, Takehiko; Taro, Yoshinori; Kawai, Tatsuo; Forrester, Steven J; Elliott, Katherine J; Choi, Eric; Daugherty, Alan; Rizzo, Victor; Eguchi, Satoru

    2015-05-01

    Angiotensin II (Ang II) has been implicated in the development of abdominal aortic aneurysm (AAA). In vascular smooth muscle cells (VSMC), Ang II activates epidermal growth factor receptor (EGFR) mediating growth promotion. We hypothesized that inhibition of EGFR prevents Ang II-dependent AAA. C57BL/6 mice were co-treated with Ang II and β-aminopropionitrile (BAPN) to induce AAA with or without treatment with EGFR inhibitor, erlotinib. Without erlotinib, 64.3% of mice were dead due to aortic rupture. All surviving mice had AAA associated with EGFR activation. Erlotinib-treated mice did not die and developed far fewer AAA. The maximum diameters of abdominal aortas were significantly shorter with erlotinib treatment. In contrast, both erlotinib-treated and non-treated mice developed hypertension. The erlotinib treatment of abdominal aorta was associated with lack of EGFR activation, endoplasmic reticulum (ER) stress, oxidative stress, interleukin-6 induction and matrix deposition. EGFR activation in AAA was also observed in humans. In conclusion, EGFR inhibition appears to protect mice from AAA formation induced by Ang II plus BAPN. The mechanism seems to involve suppression of vascular EGFR and ER stress.

  8. Cytotoxicity, in vitro models and preliminary in vivo study of dual physical and chemical gels for endovascular embolization of cerebral aneurysms.

    Science.gov (United States)

    Bearat, Hanin H; Preul, Mark C; Vernon, Brent L

    2013-09-01

    We report the evaluation of dual-gelling poly(N-isopropylacrylamide)-based polymer systems as embolic agents for intracranial aneurysms. These hydrogels undergo gelation physically via temperature-responsiveness of poly(NIPAAm) and chemically through a Michael-addition reaction between thiol and vinyl functional groups on the copolymers. Cytotoxicity studies were performed for biocompatibility of the hydrogels. In vitro glass models were utilized to assess injectability and embolization using the gelling systems and an in vivo swine model was used as proof-of-concept for catheter delivery, injection, and occlusion properties of the hydrogels. Rheology creep tests were conducted for determination of viscoelastic behavior, and degradation of the hydrogels was also investigated. Live/dead and proliferation assays indicated good biocompatibility of the hydrogels. In vitro and in vivo assessment demonstrated that the hydrogels were easily delivered via catheters into the aneurysms. Slight recanalization was observed in vivo, with some adhesion of the gels to the balloon catheter seen in vitro. The materials show creep deformation occurring with time; however, the hydrogels did not degrade over the course of 1.5 year. With the possibility to engineer hydrogels bottom-up for particular applications, these studies show properties that need to be optimized for dual-gelling polymer systems to serve as liquid-to-solid embolic agents for aneurysm treatment.

  9. Hemodynamic Changes Caused by Flow Diverters in Rabbit Aneurysm Models: Comparison of Virtual and Realistic FD Deployments Based on Micro-CT Reconstruction.

    Science.gov (United States)

    Xu, Jinyu; Deng, Benqiang; Fang, Yibin; Yu, Ying; Cheng, Jiyong; Wang, Shengzhang; Wang, Kuizhong; Liu, Jian-Min; Huang, Qinghai

    2013-01-01

    Adjusting hemodynamics via flow diverter (FD) implantation is emerging as a novel method of treating cerebral aneurysms. However, most previous FD-related hemodynamic studies were based on virtual FD deployment, which may produce different hemodynamic outcomes than realistic (in vivo) FD deployment. We compared hemodynamics between virtual FD and realistic FD deployments in rabbit aneurysm models using computational fluid dynamics (CFD) simulations. FDs were implanted for aneurysms in 14 rabbits. Vascular models based on rabbit-specific angiograms were reconstructed for CFD studies. Real FD configurations were reconstructed based on micro-CT scans after sacrifice, while virtual FD configurations were constructed with SolidWorks software. Hemodynamic parameters before and after FD deployment were analyzed. According to the metal coverage (MC) of implanted FDs calculated based on micro-CT reconstruction, 14 rabbits were divided into two groups (A, MC >35%; B, MC 0.05). The normalized mean WSS in Group A after realistic FD implantation was significantly lower than that of Group B. All parameters in Group B exhibited no significant difference between realistic and virtual FDs. This study confirmed MC-correlated differences in hemodynamic parameters between realistic and virtual FD deployment.

  10. Basic flow structure in saccular aneurysms: a flow visualization study.

    Science.gov (United States)

    Steiger, H J; Poll, A; Liepsch, D; Reulen, H J

    1987-01-01

    Basic flow patterns were investigated in a set of glass aneurysm models by means of flow visualization methods. Dye injection and streaming double refraction were used to visualize flow. The circulation inside lateral aneurysms arising at a 90 degree angle from a straight parent conduit could not be visualized by the dye-injection technique but could be demonstrated by streaming double refraction. The inflow was seen to arise from the downstream lip of the orifice and to project to the dome of the aneurysm. Backflow to the parent conduit took place along the walls of the aneurysm. In aneurysms located at bifurcations, flow characteristics depended on the geometry of the bifurcation and the flow ratio between the branches. Relatively little intra-aneurysmal flow was demonstrated in side branch-related aneurysms arising distal to an asymmetric 90 degrees bifurcation of the type encountered at the junction of the internal carotid and posterior communicating arteries. Stagnation of flow at the neck and little intra-aneurysmal circulation were found with terminal aneurysms of the basilar bifurcation type if the outflow through the branches was symmetric. With asymmetric outflow, however, or if the axis of the aneurysm did not coincide with that of the afferent vessel, an active rotation developed in these aneurysms. The size of the aneurysm had no influence on the basic pattern of intra-aneurysmal circulation. The use of pulsatile perfusion did not significantly alter the basic flow patterns observed with steady flow. Locally disturbed laminar flow was observed in certain models at physiological Reynold's numbers, but there were no signs of fully developed turbulence.

  11. CT features of mycotic aneurysms; Caracteristicas por TC de los aneurismas micoticos

    Energy Technology Data Exchange (ETDEWEB)

    Masaguer, S.; Pages, M.; Sanchez, M.; Real, M.; Ayuso, J. R.; Caralt, R. M. de; Ayuso, C. [Hospital Clinic de Barcelona (Spain)

    2003-07-01

    To describe CT features of mycotic aneurysms. We have retrospectively checked 10 patients diagnosed with mycotic aneurysm. Three revealed previously treated arteriosclerotic aneurysms, one was diabetic and had undergone a reno pancreatic transplant, and another presented advanced HIV infection. They all presented fever syndrome and eight exhibited leucocytosis. Mycotic aneurysm diagnosis was made by means of CT findings, clinical examination and positive hemo culture in all cases. Anatomopathological findings were available as confirmation for all four surgically treated patients. The CT scan was performed during arterial phase with spiral acquisition, without contrast and with endo venous administration of a contrast medium. Saccular aneurysms were found in seven patients (double aneurysms in the case of two), with seven of these being abdominal aneurysms (one retrocrural aortic,three infra renal aortic, and three iliac arteries) and two thoracic (aortic arch). In all three remaining patients, there was a pre-existing arteriosclerotic aneurysm (fusiform) and only incipient changes were observed in the adjacent fat. Perianeurysmatic soft-tissue was was noted in eight cases. Only two patients presented signs of tear (peri aneurysm hematoma and/or with contrast extravasation). In three cases, the calcium ring was disrupted. In two patients, absences were observed in other locations. In none of the cases was there gas in the aneurysm wall. Mycotic aneurysm is a rate entity, but must be considered in the evaluation of septic patients since it demands early diagnosis and treatment. In such patients, a CT finding of saccular aneurysm with adjacent soft-tissue mass, and associated with a positive hemo culture, is highly suggestive of this pathology. (Author) 9 refs.

  12. Nonstationary ARCH and GARCH with t-distributed Innovations

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Søndergaard; Rahbek, Anders

    Consistency and asymptotic normality are established for the maximum likelihood estimators in the nonstationary ARCH and GARCH models with general t-distributed innovations. The results hold for joint estimation of (G)ARCH effects and the degrees of freedom parameter parametrizing the t-distribut......Consistency and asymptotic normality are established for the maximum likelihood estimators in the nonstationary ARCH and GARCH models with general t-distributed innovations. The results hold for joint estimation of (G)ARCH effects and the degrees of freedom parameter parametrizing the t......-distribution. With T denoting sample size, classic square-root T-convergence is shown to hold with closed form expressions for the multivariate covariances....

  13. Micromanaging Abdominal Aortic Aneurysms

    Directory of Open Access Journals (Sweden)

    Lars Maegdefessel

    2013-07-01

    Full Text Available The contribution of abdominal aortic aneurysm (AAA disease to human morbidity and mortality has increased in the aging, industrialized world. In response, extraordinary efforts have been launched to determine the molecular and pathophysiological characteristics of the diseased aorta. This work aims to develop novel diagnostic and therapeutic strategies to limit AAA expansion and, ultimately, rupture. Contributions from multiple research groups have uncovered a complex transcriptional and post-transcriptional regulatory milieu, which is believed to be essential for maintaining aortic vascular homeostasis. Recently, novel small noncoding RNAs, called microRNAs, have been identified as important transcriptional and post-transcriptional inhibitors of gene expression. MicroRNAs are thought to “fine tune” the translational output of their target messenger RNAs (mRNAs by promoting mRNA degradation or inhibiting translation. With the discovery that microRNAs act as powerful regulators in the context of a wide variety of diseases, it is only logical that microRNAs be thoroughly explored as potential therapeutic entities. This current review summarizes interesting findings regarding the intriguing roles and benefits of microRNA expression modulation during AAA initiation and propagation. These studies utilize disease-relevant murine models, as well as human tissue from patients undergoing surgical aortic aneurysm repair. Furthermore, we critically examine future therapeutic strategies with regard to their clinical and translational feasibility.

  14. An Analytical Solution for Lateral Buckling Critical Load Calculation of Leaning-Type Arch Bridge

    Directory of Open Access Journals (Sweden)

    Ai-rong Liu

    2014-01-01

    Full Text Available An analytical solution for lateral buckling critical load of leaning-type arch bridge was presented in this paper. New tangential and radial buckling models of the transverse brace between the main and stable arch ribs are established. Based on the Ritz method, the analytical solution for lateral buckling critical load of the leaning-type arch bridge with different central angles of main arch ribs and leaning arch ribs under different boundary conditions is derived for the first time. Comparison between the analytical results and the FEM calculated results shows that the analytical solution presented in this paper is sufficiently accurate. The parametric analysis results show that the lateral buckling critical load of the arch bridge with fixed boundary conditions is about 1.14 to 1.16 times as large as that of the arch bridge with hinged boundary condition. The lateral buckling critical load increases by approximately 31.5% to 41.2% when stable arch ribs are added, and the critical load increases as the inclined angle of stable arch rib increases. The differences in the center angles of the main arch rib and the stable arch rib have little effect on the lateral buckling critical load.

  15. Identification of MMP1 as a novel risk factor for intracranial aneurysms in ADPKD using iPSC models

    Science.gov (United States)

    Ameku, Tomonaga; Taura, Daisuke; Sone, Masakatsu; Numata, Tomohiro; Nakamura, Masahiro; Shiota, Fumihiko; Toyoda, Taro; Matsui, Satoshi; Araoka, Toshikazu; Yasuno, Tetsuhiko; Mae, Shin-Ichi; Kobayashi, Hatasu; Kondo, Naoya; Kitaoka, Fumiyo; Amano, Naoki; Arai, Sayaka; Ichisaka, Tomoko; Matsuura, Norio; Inoue, Sumiko; Yamamoto, Takuya; Takahashi, Kazutoshi; Asaka, Isao; Yamada, Yasuhiro; Ubara, Yoshifumi; Muso, Eri; Fukatsu, Atsushi; Watanabe, Akira; Sato, Yasunori; Nakahata, Tatsutoshi; Mori, Yasuo; Koizumi, Akio; Nakao, Kazuwa; Yamanaka, Shinya; Osafune, Kenji

    2016-01-01

    Cardiovascular complications are the leading cause of death in autosomal dominant polycystic kidney disease (ADPKD), and intracranial aneurysm (ICA) causing subarachnoid hemorrhage is among the most serious complications. The diagnostic and therapeutic strategies for ICAs in ADPKD have not been fully established. We here generated induced pluripotent stem cells (iPSCs) from seven ADPKD patients, including four with ICAs. The vascular cells differentiated from ADPKD-iPSCs showed altered Ca2+ entry and gene expression profiles compared with those of iPSCs from non-ADPKD subjects. We found that the expression level of a metalloenzyme gene, matrix metalloproteinase (MMP) 1, was specifically elevated in iPSC-derived endothelia from ADPKD patients with ICAs. Furthermore, we confirmed the correlation between the serum MMP1 levels and the development of ICAs in 354 ADPKD patients, indicating that high serum MMP1 levels may be a novel risk factor. These results suggest that cellular disease models with ADPKD-specific iPSCs can be used to study the disease mechanisms and to identify novel disease-related molecules or risk factors. PMID:27418197

  16. Cephalic vein aneurysm.

    Science.gov (United States)

    Faraj, Walid; Selmo, Francesca; Hindi, Mia; Haddad, Fadi; Khalil, Ismail

    2007-11-01

    Cephalic vein aneurysms are rare malformations that may develop in any part of the vascular system, and their history, presentation, and management vary depending on their site. The etiology of venous aneurysms remains unclear, although several theories have been elaborated. Venous aneurysms are unusual vascular malformations that occur equally between the sexes and are seen at any age; they can present as either a painful or a painless subcutaneous mass. No serious complications have been reported from upper extremity venous aneurysms. Surgical excision is the definitive management for most of these. The case reported here presented with a painless and mobile, soft, subcutaneous mass that caused only cosmetic concern.

  17. Screening for aortic aneurysm after treatment of coarctation.

    Science.gov (United States)

    Hoffman, James L; Gray, Robert G; LuAnn Minich, L; Wilkinson, Stephen E; Heywood, Mason; Edwards, Reggie; Weng, Hsin Ti; Su, Jason T

    2014-01-01

    Isolated coarctation of the aorta (CoA) occurs in 6-8 % of patients with congenital heart disease. After successful relief of obstruction, patients remain at risk for aortic aneurysm formation at the site of the repair. We sought to determine the diagnostic utility of echocardiography compared with advanced arch imaging (AAI) in diagnosing aortic aneurysms in pediatric patients after CoA repair. The Congenital Heart Databases from 1996 and 2009 were reviewed. All patients treated for CoA who had AAI defined by cardiac magnetic resonance imaging (MRI), computed tomography (CT), or catheterization were identified. Data collected included the following: type, timing, and number of interventions, presence and time to aneurysm diagnosis, and mortality. Patients were subdivided into surgical and catheterization groups for analysis. Seven hundred and fifty-nine patients underwent treatment for CoA during the study period. Three hundred and ninety-nine patients had at least one AAI. Aneurysms were diagnosed by AAI in 28 of 399 patients at a mean of 10 ± 8.4 years after treatment. Echocardiography reports were available for 380 of 399 patients with AAI. The sensitivity of echocardiography for detecting aneurysms was 24 %. The prevalence of aneurysms was significantly greater in the catheterization group (p Aneurysm was also diagnosed earlier in the catheterization group compared with the surgery group (p = 0.02). Multivariate analysis showed a significantly increased risk of aneurysm diagnosis in patients in the catheterization subgroup and in patients requiring more than three procedures. Aortic aneurysms continue to be an important complication after CoA repair. Although serial echocardiograms are the test of choice for following-up most congenital cardiac lesions in pediatrics, our data show that echocardiography is inadequate for the detection of aneurysms after CoA repair. Because the time to aneurysm diagnosis was shorter and the risk greater in the

  18. Tissue Responses to Stent Grafts with Endo-Exo-Skeleton for Saccular Abdominal Aortic Aneurysms in a Canine Model

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Il Young; Chung, Jin Wook; Kim, Hyo Cheol [Dept. of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Clinical Research Institute, Seoul (Korea, Republic of); Choi, Young Ho; So Young Ho [Dept. of Radiology, Seoul National University Boramae Hospital, Seoul (Korea, Republic of); Kim, Hyun Beom [Dept. of Radiology, National Cancer Center, Goyang (Korea, Republic of); Min, Seung Kee [Dept. of Surgery, Seoul National University College of Medicine, Seoul (Korea, Republic of); Park, Jae Hyung [Dept. of Radiology, Gachon University Gil Medical Center, Incheon (Korea, Republic of)

    2014-10-15

    We evaluated the effect of close contact between the stent and the graft on the induction of endothelial covering on the stent graft placed over an aneurysm. Saccular abdominal aortic aneurysms were made with Dacron patch in eight dogs. The stent graft consisted of an inner stent, a expanded polytetrafluoroethylene graft, and an outer stent. After sacrificing the animals, the aortas with an embedded stent graft were excised. The aortas were inspected grossly and evaluated microscopically. The animals were sacrificed at two (n = 3), six (n = 3), and eight months (n = 2) after endovascular repair. In two dogs, the aortic lumen was occluded at two months after the placement. On gross inspection of specimens from the other six dogs with a patent aortic lumen, stent grafts placed over the normal aortic wall were covered by glossy white neointima, whereas, stent grafts placed over the aneurysmal aortic wall were covered by brownish neointima. On microscopic inspection, stent grafts placed over the normal aortic wall were covered by thin neointima (0.27 ± 0.05 mm, mean ± standard deviation) with an endothelial layer, and stent grafts placed over the aneurysmal aortic wall were covered by thick neointima (0.62 ± 0.17 mm) without any endothelial lining. Transgraft cell migration at the normal aortic wall was more active than that at the aneurysmal aortic wall. Close contact between the stent and the graft, which was achieved with stent grafts with endo-exo-skeleton, could not enhance endothelial covering on the stent graft placed over the aneurysms.

  19. Endothelial cell proliferation in swine experimental aneurysm after coil embolization.

    Directory of Open Access Journals (Sweden)

    Yumiko Mitome-Mishima

    Full Text Available After coil embolization, recanalization in cerebral aneurysms adversely influences long-term prognosis. Proliferation of endothelial cells on the coil surface may reduce the incidence of recanalization and further improve outcomes after coil embolization. We aimed to map the expression of proliferating tissue over the aneurysmal orifice and define the temporal profile of tissue growth in a swine experimental aneurysm model. We compared the outcomes after spontaneous thrombosis with those of coil embolization using histological and morphological techniques. In aneurysms that we not coiled, spontaneous thrombosis was observed, and weak, easily detachable proliferating tissue was evident in the aneurysmal neck. In contrast, in the coil embolization group, histological analysis showed endothelial-like cells lining the aneurysmal opening. Moreover, immunohistochemical and morphological analysis suggested that these cells were immature endothelial cells. Our results indicated the existence of endothelial cell proliferation 1 week after coil embolization and showed immature endothelial cells in septal tissue between the systemic circulation and the aneurysm. These findings suggest that endothelial cells are lead to and proliferate in the former aneurysmal orifice. This is the first examination to evaluate the temporal change of proliferating tissue in a swine experimental aneurysm model.

  20. Intraorbital ophthalmic artery aneurysm associated with basilar tip saccular aneurysm

    Energy Technology Data Exchange (ETDEWEB)

    Dehdashti, A.R.; Tribolet, N. de [Department of Neurosurgery, HUG, Geneva (Switzerland); Safran, A.B. [Department of Ophthalmology, HUG, Geneva (Switzerland); Martin, J.B.; Ruefenacht, D.A. [Division of Neuroradiology, HUG, Geneva (Switzerland)

    2002-07-01

    We present a rare case of intraorbital ophthalmic artery aneurysm found incidentally, together with a ruptured aneurysm of the tip of the basilar artery. The intraorbital aneurysm was asymptomatic, and no treatment was offered. Angiographic control was recommended to detect any progression. Treatment may be indicated for documented enlargement or significant mass effect of the aneurysm. (orig.)

  1. The Foot’s Arch and the Energetics of Human Locomotion

    Science.gov (United States)

    Stearne, Sarah M.; McDonald, Kirsty A.; Alderson, Jacqueline A.; North, Ian; Oxnard, Charles E.; Rubenson, Jonas

    2016-01-01

    The energy-sparing spring theory of the foot’s arch has become central to interpretations of the foot’s mechanical function and evolution. Using a novel insole technique that restricted compression of the foot’s longitudinal arch, this study provides the first direct evidence that arch compression/recoil during locomotion contributes to lowering energy cost. Restricting arch compression near maximally (~80%) during moderate-speed (2.7 ms−1) level running increased metabolic cost by + 6.0% (p < 0.001, d = 0.67; unaffected by foot strike technique). A simple model shows that the metabolic energy saved by the arch is largely explained by the passive-elastic work it supplies that would otherwise be done by active muscle. Both experimental and model data confirm that it is the end-range of arch compression that dictates the energy-saving role of the arch. Restricting arch compression had no effect on the cost of walking or incline running (3°), commensurate with the smaller role of passive-elastic mechanics in these gaits. These findings substantiate the elastic energy-saving role of the longitudinal arch during running, and suggest that arch supports used in some footwear and orthotics may increase the cost of running. PMID:26783259

  2. Laparo- and thoracoscopic aortic aneurysm neck optimization and treatment of potential endoleaks type IA and II in a porcine model

    DEFF Research Database (Denmark)

    Kloster, Brian Ozeraitis; Lund, Lars; Lindholt, Jes S.

    2016-01-01

    Background: Endovascular repair of aortic aneurysms has a higher incidence of late complications, and open conversion (OC) associated with high mortality may be required. As alternatives to OCs, we propose minimal invasive laparo-/thoracoscopic approaches, either to control endoleaks after endova...

  3. Laparo- and thoracoscopic aortic aneurysm neck optimization and treatment of potential endoleaks type IA and II in a porcine model

    DEFF Research Database (Denmark)

    Kloster, Brian Ozeraitis; Lund, Lars; Lindholt, Jes S

    2016-01-01

    BACKGROUND: Endovascular repair of aortic aneurysms has a higher incidence of late complications, and open conversion (OC) associated with high mortality may be required. As alternatives to OCs, we propose minimal invasive laparo-/thoracoscopic approaches, either to control endoleaks after endova...

  4. Mechanics Evolution Characteristics Analysis of Pressure-arch in Fully-mechanized Mining Field

    Directory of Open Access Journals (Sweden)

    S.R. Wang

    2014-09-01

    Full Text Available Based on a practical engineering, the three-dimension computational model was built using FLAC3D under the fullymechanized mining condition. Considering four variation factors, such as the distance of mining advancing, the strength of the surrounding rock, the speed of mining advancing and the dip angle of the coal seam, the mechanics evolution characteristics of the pressure-arch were analyzed. The result showed that for the horizontal seam, the geometric shape of the pressure-arch varied from flat arch to round arch gradually and the height and thickness of the pressure-arch also increased; the maximum principal stress in the skewback also increased with the working face advancing. With the strength of the surrounding rock from soft to hard, the arch thickness reduced, and the arch loading decreased. To improve the mining speed can do some contributions to the stability of the pressure-arch in the mining field. With the increase of dip angle of the seam, the pressure-arch displayed an asymmetric shape, the vault was tilted and moved to the upward direction. At the same time, the thickness of the pressure-arch increased, and the stress concentration in the skewback tended to be further intensified.

  5. CORRELATION BETWEEN DURATION OF BOTTLE-FEEDING AND DENTAL ARCH MEASUREMENT IN DECIDUOUS DENTITION

    Directory of Open Access Journals (Sweden)

    Meldo Mahniza

    2015-06-01

    Full Text Available The purpose of this study was to observe the correlation between duration of bottle feeding and dental arch measurement in deciduous dentition. Duration of bottle feeding was divided into 4 groups: ≤ 24 months, 25 – 36 months, 37 – 48 months, and > 48 months. The subjects were 120 kindergarten pupils, aged 3 – 5 years old. Measurements was done on the models of maxilla and mandible with digital caliper for the width and length of dental arch and using flexible curve for dental arch circumference. Pearson correlation showed a weak association for anterior arch width (r=0.206, posterior arch width (r=0.195, and anterior circumference (r=0.206 of maxilla and posterior arch width (r=0.279, anterior circumference (r=0.226 of mandible. One-way Anova was performed to analyze the differences of dental arch measurements among duration of bottle-feeding groups. The results showed that there were significant differences of dental arch measurements for anterior arch width of maxilla, posterior arch width of mandible, and anterior circumference of mandible (p<0,05.

  6. Hemodynamic effects of stenting on wide-necked intracranial aneurysms

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi-sen; LUO Bin; LI Chuan-hui; YANG Xin-jian; WANG Sheng-zhang; QIAO Ai-ke; CHEN Jia-liang; ZHANG Kun-ya; LIU Zhi-cheng; ZHAO Yu-jing; ZHANG Ying

    2010-01-01

    Background Stent placement has been widely used to assist coiling in cerebral aneurysm treatments. The present study aimed to investigate the hemodynamic effects of stenting on wide-necked intracranial aneurysms.Methods Three idealized plexiglass aneudsmal models with different geometries before and after stenting were created, and their three-dimensional computational models were constructed. Flow dynamics in stented and unstented aneurismal models were studied using in vitro flow visualization and computational fluid dynamics (CFD) simulations. In addition, effects of stenting on flow dynamics in a patient-specific aneurysm model were also analyzed by CFD.Results The results of flow visualization were consistent with those obtained with CFD simulations. Stent deployment reduced vortex inside the aneurysm and its impact on the aneurysm sac, and decreased wall shear stress on the sac.Different aneurysm geometries dictated fundamentally different hemodynamic patterns and outcomes of stenting.Conclusions Stenting across the neck of aneurysms improves local blood flow profiles. This may facilitate thrombus formation in aneurysms and decrease the chance of recanalization.

  7. Morphological and Biomechanical Differences in the Elastase and AngII apoE−/− Rodent Models of Abdominal Aortic Aneurysms

    Directory of Open Access Journals (Sweden)

    Evan H. Phillips

    2015-01-01

    Full Text Available An abdominal aortic aneurysm (AAA is a potentially fatal cardiovascular disease with multifactorial development and progression. Two preclinical models of the disease (elastase perfusion and angiotensin II infusion in apolipoprotein-E-deficient animals have been developed to study the disease during its initiation and progression. To date, most studies have used ex vivo methods to examine disease characteristics such as expanded aortic diameter or analytic methods to look at circulating biomarkers. Herein, we provide evidence from in vivo ultrasound studies of the temporal changes occurring in biomechanical parameters and macromolecules of the aortic wall in each model. We present findings from 28-day studies in elastase-perfused rats and AngII apoE−/− mice. While each model develops AAAs specific to their induction method, they both share characteristics with human aneurysms, such as marked changes in vessel strain and blood flow velocity. Histology and nonlinear microscopy confirmed that both elastin and collagen, both important extracellular matrix molecules, are similarly affected in their levels and spatial distribution. Future studies could make use of the differences between these models in order to investigate mechanisms of disease progression or evaluate potential AAA treatments.

  8. Aneurismas da aorta Aortic aneurysms

    Directory of Open Access Journals (Sweden)

    Januário M Souza

    1992-09-01

    Full Text Available Entre janeiro de 1979 e janeiro de 1992, foram realizadas 212 operações para correção de aneurismas e de dissecções da aorta. Neste trabalho serão analisados 104 procedimentos cirúrgicos (em 97 pacientes para correção de aneurismas. A idade dos pacientes variou de 14 a 79 anos (média 59,5 anos e o sexo predominante foi o masculino, com 75 pacientes. Os aneurismas localizavam-se na aorta ascendente em 46 pacientes, na croça em 8, na aorta descendente em 8, na aorta toráco-abdominal em 8, na aorta abdominal em 21, na aorta descendente e abdominal em 2, na aorta ascendente e tóraco-abdominal em 2, na aorta ascendente e descendente em 1, na aorta ascendente, croça e descendente em 1. Doenças cardiovasculares associadas estavam presentes em 39 pacientes, sendo valvopatia aórtica em 18 (excluídos os pacientes com ectasiaânulo-aórtíca, insuficiência coronária em 17, coarctação da aorta em 2, persistência do canal arterial em 1 e valvopatia mitral e aórtica em 1. A mortalidade imediata (hospitalar e/ou 30 dias foi de 14,4%, sendo de 27,7% (5/18 para pacientes com mais de 70 anos e de 11,3% (9/79 para pacientes com idade inferior a 70 anos. Os aneurismas localizados na aorta ascendente e croça foram operados como o auxílio de circulação extracorpórea. Parada circulatória e hipotermia profunda foram utilizadas em todos os pacientes com aneurisma da croça. O estudo tomográfico e angiográfico deve ser de toda a aorta, pela possibilidade de aneurismas de localizações múltiplas.Among 212 patients undergoing operation for aortic aneurysm and aortic dissection between January 1979 and January 1992, 97 were operated on for aneurysms. The aneurysms were localized in: ascending aorta in 46 patients, transverse aortic arch in 8, descending aorta in 8, thoracoabdominal aorta in 8, abdominal (infrarenal aorta in 21, descending and abdominal aorta in 2, ascending and thoracoabdominal aorta in 2, ascending and descending in 1

  9. 应用LOM法制作-下颌骨及牙列的三维实体模型%3D Solid Model of Mandible with Dental Arch via LOM Method

    Institute of Scientific and Technical Information of China (English)

    张睿; 李玲; 于力牛; 白瑞军; 张富强; 王成焘; 徐肖云

    2000-01-01

    Objective Based on 3D reconstruction data from CT scaning, a solid model of mandible with dental arch is ob tained via a rapid prototype machine using LOM method. Method 3D reconstruction data is transferred to STL file using software of Delcam(UK) , which will be fed to Magics RP software for detection and rebuilding. Reproduction of the papery model of mandible with dental arch is then performed with highly geometric sunilarity. Result The RP model of mandible with dental arch is obtained. Conclusion Accuracy of the reproduction model meets the demands of studies in prosthetic dentist, which gives the possibility of computer aided design of prosthetic dentistry based on 3D solid model.%采用基于CT断层影像的下颌骨及牙列三维重建数据,利用快速成型中的分层制造方法复制下颌骨 及牙列。方法利用Delcam公司(UK)软件将下颌骨及牙列三维重建的数据文件转换为STL文件,采用Magics RP 软件读入STL文件并进行检验与修补。制作下颌骨及牙列纸质实物模型,与下颌骨及牙列标本模型的几何相似性 良好。结果得到了下颌骨及下牙列的快速原型模型。结论下颌骨及牙列复制模型精度符合口腔修复中的要 求,可在其计算机三维实体模型基础上进行牙列缺损的计算机辅助修复设计。

  10. Theory of Arched Structures Strength, Stability, Vibration

    CERN Document Server

    Karnovsky, Igor A

    2012-01-01

    Theory of Arched Structures: Strength, Stability, Vibration presents detailed procedures for analytical analysis of the strength, stability, and vibration of arched structures of different types, using exact analytical methods of classical structural analysis. The material discussed is divided into four parts. Part I covers stress and strain with a particular emphasis on analysis; Part II discusses stability and gives an in-depth analysis of elastic stability of arches and the role that matrix methods play in the stability of the arches; Part III presents a comprehensive tutorial on dynamics and free vibration of arches, and forced vibration of arches; and Part IV offers a section on special topics which contains a unique discussion of plastic analysis of arches and the optimal design of arches.

  11. Arch bridges – unlocking their potential

    OpenAIRE

    Long, Adrian; Nanukuttan, Sreejith

    2016-01-01

    Arch bridges are strong, durable, aesthetically pleasing and require little maintenance but very few have been built since the early 1900s. However, this trend has changed as more than 60 FlexiArch bridges have been installed since the system was launched in 2007. The FlexiArch uses precast concrete voussoirs, requires neither corrodible reinforcement, nor centring, can be installed in hours and is contractor friendly. Details of this innovative method of construction and installation of arch...

  12. Wall shear stress at the initiation site of cerebral aneurysms.

    Science.gov (United States)

    Geers, A J; Morales, H G; Larrabide, I; Butakoff, C; Bijlenga, P; Frangi, A F

    2017-02-01

    Hemodynamics are believed to play an important role in the initiation of cerebral aneurysms. In particular, studies have focused on wall shear stress (WSS), which is a key regulator of vascular biology and pathology. In line with the observation that aneurysms predominantly occur at regions of high WSS, such as bifurcation apices or outer walls of vascular bends, correlations have been found between the aneurysm initiation site and high WSS. The aim of our study was to analyze the WSS field at an aneurysm initiation site that was neither a bifurcation apex nor the outer wall of a vascular bend. Ten cases with aneurysms on the A1 segment of the anterior cerebral artery were analyzed and compared with ten controls. Aneurysms were virtually removed from the vascular models of the cases to mimic the pre-aneurysm geometry. Computational fluid dynamics (CFD) simulations were created to assess the magnitude, gradient, multidirectionality, and pulsatility of the WSS. To aid the inter-subject comparison of hemodynamic variables, we mapped the branch surfaces onto a two-dimensional parametric space. This approach made it possible to view the whole branch at once for qualitative evaluation. It also allowed us to empirically define a patch for quantitative analysis, which was consistent among subjects and encapsulated the aneurysm initiation sites in our dataset. To test the sensitivity of our results, CFD simulations were repeated with a second independent observer virtually removing the aneurysms and with a 20 % higher flow rate at the inlet. We found that branches harboring aneurysms were characterized by high WSS and high WSS gradients. Among all assessed variables, the aneurysm initiation site most consistently coincided with peaks of temporal variation in the WSS magnitude.

  13. Ortner's Syndrome: Secondary Laryngeal Paralysis Caused by a Great Thoracic Aorta Aneurysm

    Directory of Open Access Journals (Sweden)

    Zangirolami, Ana Claudia Alves

    2015-01-01

    Full Text Available Introduction Recurrent laryngeal nerve injury caused by cardiovascular disease is a rare condition, and often it is the only prominent sign of an imminent break of an aortic artery aneurysm. Objective To report left laryngeal paralysis caused by a great aortic arch aneurysm and to highlight the importance of an otorhinolaryngologic evaluation along with a thoracic radiologic study. Resumed Report A 42-year-old man complained of thickness of his voice and dysphagia for 3 months, but no thoracic pain or other relevant complaints. Video laryngoscopy revealed immobility of his left vocal fold in the paramedian position. Imaging was obtained for investigation, including magnetic resonance imaging of his thorax, which showed a fusiform aneurysm in the aortic arch, leading to recurrent compression of the left laryngeal nerve. The patient was successfully treated with endovascular repair of the aneurysm. At 2-month follow-up, there was still no recovery of the laryngeal mobility. Conclusion An aortic artery aneurysm can suddenly break, requiring emergency heart surgery, and the results can be fatal in many cases. We suggest routine exam of the vocal folds in all patients with a heart condition, and we review the literature and suggest the use of imaging to reduce the number of emergency procedures.

  14. Thoracic type Ia endoleak: direct percutaneous coil embolization of the aortic arch at the blood entry site after TEVAR and double-chimney stent-grafts

    Energy Technology Data Exchange (ETDEWEB)

    Bangard, Christopher; Franke, Mareike; Maintz, David; Chang, De-Hua [University Hospital, University of Cologne, Department of Radiology, Cologne (Germany); Pfister, Roman [University Hospital, University of Cologne, Department of Internal Medicine III, Cologne (Germany); Deppe, Antje-Christin [University Hospital, University of Cologne, Department of Cardiothoracic Surgery, Cologne (Germany); Matoussevitch, Vladimir [University Hospital, University of Cologne, Department of Vascular Surgery, Cologne (Germany)

    2014-06-15

    To introduce a novel percutaneous technique to stop blood entry at the lesser aortic arch curvature by coil embolisation in type Ia endoleak after TEVAR. A 61-year-old Marfan patient presented with type Ia endoleak of the aortic arch and a growing aortic arch pseudoaneurysm after TEVAR. Multiple preceding operations and interventions made an endovascular approach unsuccessful. Direct percutaneous puncture of the aneurysmal sac would have cured the sign, but not the cause of blood entry at the lesser curvature of the aortic arch. Direct CT-guided percutaneous puncture of the blood entry site in the aortic arch with fluoroscopically guided coil embolisation using detachable extra-long coils was successfully performed. Three weeks after the intervention, the patient developed fever because of superinfection of the pseudoaneurysm. The blood cultures and CT-guided mediastinal aspirate were sterile. After intravenous administration of antibiotics, the fever disappeared and the patient recovered. Six-month follow-up showed permanent closure of the endoleak and a shrinking aneurysmal sac. Direct percutaneous puncture of the aortic arch at the blood entry site of a thoracic type Ia endoleak after TEVAR and double-chimney stent-grafts with coil embolisation of the wedge-shaped space between the lesser aortic curvature and the stent-graft is possible. (orig.)

  15. Pediatric cerebral aneurysms.

    Science.gov (United States)

    Gemmete, Joseph J; Toma, Ahmed K; Davagnanam, Indran; Robertson, Fergus; Brew, Stefan

    2013-11-01

    Childhood intracranial aneurysms differ from those in the adult population in incidence and gender prevalence, cause, location, and clinical presentation. Endovascular treatment of pediatric aneurysms is the suggested approach because it offers both reconstructive and deconstructive techniques and a better clinical outcome compared with surgery; however, the long-term durability of endovascular treatment is still questionable, therefore long-term clinical and imaging follow-up is necessary. The clinical presentation, diagnosis, and treatment of intracranial aneurysms in children are discussed, and data from endovascular treatments are presented.

  16. 快速成型技术制备仿生主动脉弓模型的研究%Preliminary study on rapid prototyping to prepare biomimetic model of aortic arch

    Institute of Scientific and Technical Information of China (English)

    陈鹏飞; 严中亚; 申运华; 陈向东; 邓克学

    2015-01-01

    目的 创建与人体解剖结构一致的仿真主动脉弓三维快速成型模型,探讨其对促进规划和执行主动脉弓外科手术的帮助,为构建个体化人工血管支架及3D打印生物组织或器官进行前期准备.方法 对正常成年男性进行胸部CT扫描,获得该男子主动脉弓原始CT数据(DICOM),通过Mimics 10.01软件对DICOM数据处理,分割出主动脉弓的区域,计算主动脉弓三维立体模型,导出三维模型数据文件(STL文件),最后通过3D打印机打印出主动脉弓三维模型.结果 基于CT获得的胸部解剖结构的数据,通过MIMICS 10.01软件进行处理并导出STL格式文件后,可直接用3D打印机打印出与人体主动脉弓解剖结构基本一致的主动脉弓模型(比例1∶1).结论 快速成型技术制备的主动脉弓模型对手术规划有临床意义,有助于构建个体化人工血管支架及3D打印生物组织或器官.%Objective To create an anatomical correct 3D rapid prototyping (RP) model for a volunteer' s aortic arch and investigate the significance of aortic arch model for surgical planning.To make the early preparations for the mannufacture of individualize artificial vascular stents and 3D printing with biological tissue or organ.Methods Based on the extracted 3D contour image from volunteer' s chest CT data,the custom-made artificial aortic arch was designed with mimics 10.01 software and form 3D printing STL file.And then a aortic arch model was printed out by 3D printer.Results The data acquired by CT scanner can be rapidly prototyped after being edited with Mimics 10.01 software and directly used by 3D printing system to construct a aortic arch model (1∶1).Conclusion The artificial 3D aortic arch model has significance in surgical planning and great help for the mannufacture of individualize artificial vascular stents and 3D printing with biological tissue or organ.

  17. Cerebral Aneurysms Fact Sheet

    Science.gov (United States)

    ... the flow of blood to the aneurysm. Under anesthesia, a section of the skull is removed and ... Page NINDS Inclusion Body Myositis Information Page Traumatic Brain Injury Information Page NINDS Incontinentia Pigmenti Information Page Trigeminal ...

  18. Intracranial Arterial Aneurysms

    OpenAIRE

    J Gordon Millichap

    1988-01-01

    Neurosurgeons from the Universita degli Studi di Roma “La Saspeinza,” Rome, Italy, report a 4-year-old girl with a cerebral saccular aneurysm and analyze 71 cases under 5 years of age in the literature.

  19. Advancements in identifying biomechanical determinants for abdominal aortic aneurysm rupture.

    Science.gov (United States)

    Kontopodis, Nikolaos; Metaxa, Eleni; Papaharilaou, Yannis; Tavlas, Emmanouil; Tsetis, Dimitrios; Ioannou, Christos

    2015-02-01

    Abdominal aortic aneurysms are a common health problem and currently the need for surgical intervention is determined based on maximum diameter and growth rate criteria. Since these universal variables often fail to predict accurately every abdominal aortic aneurysms evolution, there is a considerable effort in the literature for other markers to be identified towards individualized rupture risk estimations and growth rate predictions. To this effort, biomechanical tools have been extensively used since abdominal aortic aneurysm rupture is in fact a material failure of the diseased arterial wall to compensate the stress acting on it. The peak wall stress, the role of the unique geometry of every individual abdominal aortic aneurysm as well as the mechanical properties and the local strength of the degenerated aneurysmal wall, all confer to rupture risk. In this review article, the assessment of these variables through mechanical testing, advanced imaging and computational modeling is reviewed and the clinical perspective is discussed.

  20. The Layout and Simulation of Logarithmic Spiral Double Curved Arch Dam Transverse Joints%The Layout and Simulation of Logarithmic Spiral Double Curved Arch Dam Transverse Joints

    Institute of Scientific and Technical Information of China (English)

    DU Ting-na; DU Qi-lu; HUI Yuan

    2011-01-01

    Because of its good condition with mechanics, logarithmic spiral double curve arch bam has been widely used in the practical engineering. The introduction of a new method in how to divide transverse joint in arch dam will be given and the further research of its calculation has been done. The C++ is used in electronic procedure and the 3D simulation has been finished with AutoCAD, which will provide the object model for computer simulation of the arch dam and the division of finite element mesh. Meanwhile, this method in dividing the transverse joint in arch dam also can be taken as the calculated basis for the design and calculation of arch dam, construction lofting and the calculation of the work amount.

  1. Out-of-plane free vibration analysis of a cable-arch structure

    Science.gov (United States)

    Kang, H. J.; Zhao, Y. Y.; Zhu, H. P.

    2013-02-01

    Cable-arch structure has been widely used in many long-span structures such as cable roofs and cable-stayed arch bridges, but its dynamics is still not well understood. In this paper, the out-of-plane dynamic behavior of a cable-arch structure is investigated. The equations governing the out-of-plane free vibration of the structure are derived using d'Alembert's principle. A transfer matrix method is used to solve the governing equations and determine the frequencies of the out-of-plane vibration. The theories are then used to study two specific cases: free vibration of a model cable-arch and simulation of an arch erection process. The effects of some key parameters of cable and arch, such as tension of cable and radius, open-angle and shape of arch, are examined. The results indicate that in-plane and spatial cables can largely improve the out-of-plane dynamic behavior of arch structures, which are further verified by analyzing the out-of-plane buckling of cable-arch structures. The present work should be valuable and significant not only for the fundamental research but also engineering design of roofs and bridges.

  2. Haemodynamics of giant cerebral aneurysm: A comparison between the rigid-wall, one-way and two-way FSI models

    Science.gov (United States)

    Khe, A. K.; Cherevko, A. A.; Chupakhin, A. P.; Bobkova, M. S.; Krivoshapkin, A. L.; Orlov, K. Yu

    2016-06-01

    In this paper a computer simulation of a blood flow in cerebral vessels with a giant saccular aneurysm at the bifurcation of the basilar artery is performed. The modelling is based on patient-specific clinical data (both flow domain geometry and boundary conditions for the inlets and outlets). The hydrodynamic and mechanical parameters are calculated in the frameworks of three models: rigid-wall assumption, one-way FSI approach, and full (two-way) hydroelastic model. A comparison of the numerical solutions shows that mutual fluid- solid interaction can result in qualitative changes in the structure of the fluid flow. Other characteristics of the flow (pressure, stress, strain and displacement) qualitatively agree with each other in different approaches. However, the quantitative comparison shows that accounting for the flow-vessel interaction, in general, decreases the absolute values of these parameters. Solving of the hydroelasticity problem gives a more detailed solution at a cost of highly increased computational time.

  3. Treatment of infrarenal abdominal aortic dissection concomitant with an aneurysm

    Institute of Scientific and Technical Information of China (English)

    WANG Li-xin; ZHU Ting; FU Wei-guo; WANG Yu-qi; XI Xun; GUO Da-qiao; CHEN Bin; JIANG Jun-hao; YANG Ju; SHI Zhen-yu

    2007-01-01

    @@ Aortic dissection occurs when layers of the aortic walls are separated by the blood flow through an intimal tear. Dissection of the aorta most frequently originates in the ascending aorta (70%), followed by the descending aorta (22%), the aortic arch (7%) and the abdominal aorta (1/%).1 The dissection limited to the abdominal aorta is rare.2 An isolated abdominal aortic dissection (IAAD) concomitant with an abdominal aortic aneurysm (AAA) is uncommon. We present here one patient with IAAD and AAA treated by endovascular therapy.

  4. Study on Forest Products PPI Index Fluctuation in China Based on ARCH Family-HP Filter Model%中国林产品PPI指数波动的ARCH族-HP滤波分析

    Institute of Scientific and Technical Information of China (English)

    张宇青; 周应恒

    2013-01-01

    了解林产品生产者价格指数波动的特征对稳定林产品PPI和价格水平有重要意义。采用ARCH-LM和残差平方和相关图方法检验后认为:木材、竹材PPI序列不存在不存在ARCH效应;HP滤波分析显示木材和竹材行业的P P I指数长期趋势比较平稳,相比于木材市场,近期竹材的市场供求状态相对合理;采用GARCH-M、 TARCH和EARCH模型分析认为胶脂和果实类林产品市场不存在“高风险-高收益”特征,但胶脂和果实类林产品PPI指数波动存在非对称性。%It’s important to Learn characteristics of forest products producer price index volatility for stable PPI and the price level. After Using ARCH-LM and the residual sum of squares correlation di-agram method. We considerst that: wood, bamboo PPI does not exist ARCH effect, HP filter analy-sis shows wood and bamboo industry PPI index slong-term trend is relatively stable, compared to the timber market, supply and demand status of bamboo market relatively reasonable;using GARCH-M, TARCH and EARCH model analysis that plastic resin and fruit category forest products does not exist“high risk - high return” feature, but it’s PPI index fluctuations exist asymmetry.

  5. Endovascular treatment of very small intracranial aneurysms

    DEFF Research Database (Denmark)

    Iskandar, A; Nepper-Rasmussen, J

    2011-01-01

    The endovascular treatment of intracranial aneurysms 3 mm or less is considered controversial. The purpose of this study is to report angiographic and clinical results following coiling of such aneurysms and compare them to those of larger aneurysms (> 3 mm).Between November 1999 and November 2009...... endovascular treatment was attempted in 956 consecutive intracranial aneurysms. Of 956 aneurysms, 111 aneurysms were very small aneurysms with a maximal diameter of 3 mm or less. We conducted a retrospective analysis of angiographic and clinical outcome following coiling of very small aneurysms...... and subsequently comparing it to the results of larger aneurysms.Coiling initially failed in eight aneurysms. In the remaining 103 aneurysms endovascular treatment was accomplished and immediate angiographic results showed complete aneurysm occlusion in 43 aneurysms, nearly complete aneurysm occlusion in 54...

  6. Screening for Abdominal Aortic Aneurysm

    Science.gov (United States)

    Understanding Task Force Recommendations Screening for Abdominal Aortic Aneurysm The U.S. Preventive Services Task Force (Task Force) has issued a final recommendation statement on Screening for Abdominal Aortic Aneurysm. This final ...

  7. Abdominal aortic aneurysm repair - open

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007392.htm Abdominal aortic aneurysm repair - open To use the sharing features on this page, please enable JavaScript. Open abdominal aortic aneurysm repair is surgery to fix a widened part ...

  8. Comparison between different plantar arch

    OpenAIRE

    2009-01-01

    The longitudinal plantar arch (LPA) perform biomechanics functions in the foot. The aim of this study was to compare the relationship between different index to measure the LPA of the foot. The arc index, Staheli index, Viladot classification and Feiss line were compared. In the transversal study, the experimental samples were soccer players females with age between 13 to 19 years. The measure were performed by plantigraphy, with out Feiss line. Although non significant the higher agreement w...

  9. Blood flow characteristics in the aortic arch

    Science.gov (United States)

    Prahl Wittberg, Lisa; van Wyk, Stevin; Mihaiescu, Mihai; Fuchs, Laszlo; Gutmark, Ephraim; Backeljauw, Philippe; Gutmark-Little, Iris

    2012-11-01

    The purpose with this study is to investigate the flow characteristics of blood in the aortic arch. Cardiovascular diseases are associated with specific locations in the arterial tree. Considering atherogenesis, it is claimed that the Wall Shear Stress (WSS) along with its temporal and spatial gradients play an important role in the development of the disease. The WSS is determined by the local flow characteristics, that in turn depends on the geometry as well as the rheological properties of blood. In this numerical work, the time dependent fluid flow during the entire cardiac cycle is fully resolved. The Quemada model is applied to account for the non-Newtonian properties of blood, an empirical model valid for different Red Blood Cell loading. Data obtained through Cardiac Magnetic Resonance Imaging have been used in order to reconstruct geometries of the the aortic arch. Here, three different geometries are studied out of which two display malformations that can be found in patients having the genetic disorder Turner's syndrome. The simulations show a highly complex flow with regions of secondary flow that is enhanced for the diseased aortas. The financial support from the Swedish Research Council (VR) and the Sweden-America Foundation is gratefully acknowledged.

  10. The Arches Cluster Mass Function

    CERN Document Server

    Kim, S S; Kudritzki, R P; Najarro, F; Kim, Sungsoo S.; Figer, Donald F.; Kudritzki, Rolf P.

    2006-01-01

    We have analyzed H and K_s-band images of the Arches cluster obtained using the NIRC2 instrument on Keck with the laser guide star adaptive optics (LGS AO) system. With the help of the LGS AO system, we were able to obtain the deepest ever photometry for this cluster and its neighborhood, and derive the background-subtracted present-day mass function (PDMF) down to 1.3 Msun for the 5 arcsec-9 arcsec annulus of the cluster. We find that the previously reported turnover at 6 Msun is simply due to a local bump in the mass function (MF), and that the MF continues to increase down to our 50 % completeness limit (1.3 Msun) with a power-law exponent of Gamma = -0.91 for the mass range of 1.3 < M/Msun < 50. Our numerical calculations for the evolution of the Arches cluster show that the Gamma values for our annulus increase by 0.1-0.2 during the lifetime of the cluster, and thus suggest that the Arches cluster initially had Gamma of -1.0 ~ -1.1, which is only slightly shallower than the Salpeter value.

  11. Cyclophilin A in Ruptured Intracranial Aneurysm: A Prognostic Biomarker.

    Science.gov (United States)

    Kao, Hung-Wen; Lee, Kwo-Whei; Chen, Wei-Liang; Kuo, Chen-Ling; Huang, Ching-Shan; Tseng, Wan-Min; Liu, Chin-San; Lin, Ching-Po

    2015-09-01

    Cyclophilin A (CyPA), an oxidative stress-induced factor, was found to play an important role in the aneurysm formation. Our working hypothesis was that the plasma level of CyPA in ruptured intracranial aneurysm could predict the neurological outcome. From 2011 to 2013, a total of 36 patients with ruptured saccular intracranial aneurysm were recruited in our study. Before coil embolization, we draw blood samples at the orifice of a culprit aneurysm and in the remote peripheral vein for measurements of the CyPA levels. We utilized the modified Rankin scale 30 days after aneurysm rupture as the outcome measure. Generalized linear models were used to estimate the adjusted odds ratios of the poor neurological outcome given the presence of high plasma level of CyPA. The aneurysmal and venous CyPA levels were significantly associated with the initial clinical severity (P = 0.004 and 0.03, respectively) and 30-day outcome (P = 0.01 and 0.02, respectively). The aneurysmal CyPA levels modestly correlated with age and high Fisher grade (ρ = 0.39 and 0.41; P = 0.02 and 0.01, respectively). The aneurysmal CyPA levels strongly correlated with the venous counterpart (ρ = 0.89; P aneurysmal CyPA were 15.66 times (95% CI, 1.48-166.24; P = 0.02) more likely to have worse neurological outcome than those with the low levels after adjustment of the age, gender, and the documented confounding factors. High plasma level of CyPA is a significant prognostic biomarker for poor neurological outcome in patients with ruptured intracranial aneurysm.

  12. Risk of Familial Intracranial Aneurysm

    OpenAIRE

    J Gordon Millichap; Millichap, John J.

    2014-01-01

    Investigators at University Medical Center Utrecht, Netherlands, studied the yield of long-term (up to 20 years) screening for intracranial aneurysms in individuals with a positive family history (2 or more first-degree relatives) of aneurysmal subarachnoid hemorrhage (aSAH) or unruptured intracranial aneurysm (1993-2013).

  13. AutoCAD Civil 3D在双曲拱坝建模中的应用%Application of AutoCAD Civil3D in Modeling of Double-Curvature Arch Dam

    Institute of Scientific and Technical Information of China (English)

    王奕钦

    2015-01-01

    With the case of the double-curvature arch dam whose outline is complicated in water resources and hydropower projects.Applica-tion of Civil 3D in dam modeling is described in terms of establishment of the original topographic curve, arrangement of components of the arch-dam outline, setting-out of the dam arc curve, slope excavation, calculation of work quantities of excavation and backfill, etc.The ap-plication prospects of the application of AutoCAD Civil 3D in water resources and hydropower projects are summarized, providing the designer of water resources and hydropower projects with reference.%以水利水电工程中大坝体型较为复杂的双曲拱坝为例,从原始地形曲面创建、拱坝体型装配设置、大坝圆弧曲线放样、边坡开挖、挖填方工程量计算等方面介绍了Civil 3D在水利工程中坝体建模方面的应用。总结了Au-toCAD Civil 3D在在水利工程中的应用前景,可为水利水电工程设计者提供参考。

  14. [Inflammatory abdominal aortic aneurysm].

    Science.gov (United States)

    Ziaja, K; Sedlak, L; Urbanek, T; Kostyra, J; Ludyga, T

    2000-01-01

    The reported incidence of inflammatory abdominal aortic aneurysm (IAAA) is from 2% to 14% of patients with abdominal aortic aneurysm and the etiology of this disease is still discussed--according to the literature several pathogenic theories have been proposed. From 1992 to 1997 32 patients with IAAA were operated on. The patients were mostly symptomatic--abdominal pain was present in 68.75% cases, back pain in 31.25%, fever in 12.5% and weight loss in 6.25% of the operated patients. In all the patients ultrasound examination was performed, in 4 patients CT and in 3 cases urography. All the patients were operated on and characteristic signs of inflammatory abdominal aortic aneurysm like: thickened aortic wall, perianeurysmal infiltration or retroperitoneal fibrosis with involvement of retroperitoneal structures were found. In all cases surgery was performed using transperitoneal approach; in three cases intraoperatively contiguous abdominal organs were injured, which was connected with their involvement into periaortic inflammation. In 4 cases clamping of the aorta was done at the level of the diaphragmatic hiatus. 3 patients (9.37%) died (one patient with ruptured abdominal aortic aneurysm). Authors present diagnostic procedures and the differences in the surgical tactic, emphasizing the necessity of the surgical therapy in patients with inflammatory abdominal aortic aneurysm.

  15. Three-dimensional printing technology for treatment of intracranial aneurysm

    Institute of Scientific and Technical Information of China (English)

    Yin Kang; LiangHong Yu; Tao Xu; ShuFa Zheng; PeiSen Yao; Man Liu; YuanXiang Lin

    2016-01-01

    Background:The development of three-dimensional (3D) printing technology provides a new method for surgical treatment,but currently there are few reports on its application in the treatment of aneurysm.The aim of the present study was to explore the materials and methods of fabricating 3D printed individual aneurysm model and its value in the treatment of intracranial aneurysm.Methods:Twenty-four patients with intracranial aneurysm diagnosed by CTA who had undergone operation in our hospital were analyzed retrospectively.CTA Data collected at the time of surgery was used for reconstruction.Soft Mimics 17.0 was used to reconstruct the thin layer CTA scan data into 3D image and the final data was sent to the 3D printer for fabricating the model.We compared the proposed 3D printed model-based preoperative plan and the actual approach used in the surgery based on CTA data to evaluate the value of the 3D printed model in preoperative planning,and picked out the materials which were more suitable for the clinic.Results:Twenty-four aneurysm models with high degree of reality were fabricated successfully with 3D-printing technology.The patients' blood vessels,skulls and aneurysms were printed into the reality model at a ratio of 1:1.It is reported that the soft material-based,3D printed vascular and aneurysm model more closely resembled the characteristics of the real blood vessels,thus provides a better simulation compared to the plaster-based model.Compared with the original operation plan,3D printed model could be used for pre-operative aneurysm clip selection,and provide more intuitive information in selection of operational approach.Conclusions:3D printed model can be used as an operational physical model to design operative schemes,choose the best operative paths and select suitable aneurysm clips by its high simulation degree and individualized characteristics.The model is helpful for surgical planning,especially for the preoperative plan of treating refractory

  16. Optical silencing of C. elegans cells with arch proton pump.

    Directory of Open Access Journals (Sweden)

    Ayako Okazaki

    Full Text Available BACKGROUND: Optogenetic techniques using light-driven ion channels or ion pumps for controlling excitable cells have greatly facilitated the investigation of nervous systems in vivo. A model organism, C. elegans, with its small transparent body and well-characterized neural circuits, is especially suitable for optogenetic analyses. METHODOLOGY/PRINCIPAL FINDINGS: We describe the application of archaerhodopsin-3 (Arch, a recently reported optical neuronal silencer, to C. elegans. Arch::GFP expressed either in all neurons or body wall muscles of the entire body by means of transgenes were localized, at least partially, to the cell membrane without adverse effects, and caused locomotory paralysis of worms when illuminated by green light (550 nm. Pan-neuronal expression of Arch endowed worms with quick and sustained responsiveness to such light. Worms reliably responded to repeated periods of illumination and non-illumination, and remained paralyzed under continuous illumination for 30 seconds. Worms expressing Arch in different subsets of motor neurons exhibited distinct defects in the locomotory behavior under green light: selective silencing of A-type motor neurons affected backward movement while silencing of B-type motor neurons affected forward movement more severely. Our experiments using a heat-shock-mediated induction system also indicate that Arch becomes fully functional only 12 hours after induction and remains functional for more than 24 hour. CONCLUSIONS/SGNIFICANCE: Arch can be used for silencing neurons and muscles, and may be a useful alternative to currently widely used halorhodopsin (NpHR in optogenetic studies of C. elegans.

  17. 基于ARMA-ARCH模型的风电场风速预测研究%Wind Speed Forecast for Wind Farms Based on ARMA-ARCH Model

    Institute of Scientific and Technical Information of China (English)

    何育; 高山; 陈昊

    2009-01-01

    风速预测对风电场规划设计和电力系统的运行都具有重要意义.对采样时间为15 min的风速时间序列建立自回归移动平均(ARMA)模型,利用拉格朗日乘数法检验ARMA模型残差的自回归条件异方差(ARCH)效应,建立ARMA-ARCH模型.分别使用ARMA模型和ARMA-ARCH模型对风速时间序列进行短期预测,并比较两者精度.结果表明,ARMA-ARCH模型具有更高的预测精度,具有一定的实用价值.

  18. Revisiting impressions using dual-arch trays.

    Science.gov (United States)

    Small, Bruce W

    2012-01-01

    Making routine perfect impressions is the goal of any restorative dentist. Using dual-arch trays is an easy, repeatable way to accomplish that goal, as long as each step is done before the next and each step is performed perfectly. This column reviewed several articles that support the metal dual-arch concept and provided some clinical tips that might help restorative dentists. The dual-arch technique does have its limits and is meant for one or two teeth in a quadrant when there are other teeth to occlude with. Also, if the case involves anterior guidance, a full-arch impression maybe advisable.

  19. Combined surgical and catheter-based treatment of extensive thoracic aortic aneurysm and aortic valve stenosis

    DEFF Research Database (Denmark)

    De Backer, Ole; Lönn, Lars; Søndergaard, Lars

    2015-01-01

    endovascular aneurysm repair (TEVAR) has changed and extended management options in thoracic aorta disease, including in those patients deemed unfit or unsuitable for open surgery. Accordingly, transcatheter aortic valve replacement (TAVR) is increasingly used to treat patients with symptomatic severe aortic...... valve stenosis (AS) who are considered at high risk for surgical aortic valve replacement. In this report, we describe the combined surgical and catheter-based treatment of an extensive TAA and AS. To our knowledge, this is the first report of hybrid TAA repair combined with TAVR.......An extensive thoracic aortic aneurysm (TAA) is a potentially life-threatening condition and remains a technical challenge to surgeons. Over the past decade, repair of aortic arch aneurysms has been accomplished using both hybrid (open and endovascular) and totally endovascular techniques. Thoracic...

  20. Aneurysmal Subarachnoid Hemorrhage and Neuroinflammation: A Comprehensive Review

    Science.gov (United States)

    Lucke-Wold, Brandon P.; Logsdon, Aric F.; Manoranjan, Branavan; Turner, Ryan C.; McConnell, Evan; Vates, George Edward; Huber, Jason D.; Rosen, Charles L.; Simard, J. Marc

    2016-01-01

    Aneurysmal subarachnoid hemorrhage (SAH) can lead to devastating outcomes including vasospasm, cognitive decline, and even death. Currently, treatment options are limited for this potentially life threatening injury. Recent evidence suggests that neuroinflammation plays a critical role in injury expansion and brain damage. Red blood cell breakdown products can lead to the release of inflammatory cytokines that trigger vasospasm and tissue injury. Preclinical models have been used successfully to improve understanding about neuroinflammation following aneurysmal rupture. The focus of this review is to provide an overview of how neuroinflammation relates to secondary outcomes such as vasospasm after aneurysmal rupture and to critically discuss pharmaceutical agents that warrant further investigation for the treatment of subarachnoid hemorrhage. We provide a concise overview of the neuroinflammatory pathways that are upregulated following aneurysmal rupture and how these pathways correlate to long-term outcomes. Treatment of aneurysm rupture is limited and few pharmaceutical drugs are available. Through improved understanding of biochemical mechanisms of injury, novel treatment solutions are being developed that target neuroinflammation. In the final sections of this review, we highlight a few of these novel treatment approaches and emphasize why targeting neuroinflammation following aneurysmal subarachnoid hemorrhage may improve patient care. We encourage ongoing research into the pathophysiology of aneurysmal subarachnoid hemorrhage, especially in regards to neuroinflammatory cascades and the translation to randomized clinical trials. PMID:27049383

  1. Aneurysmal Subarachnoid Hemorrhage and Neuroinflammation: A Comprehensive Review

    Directory of Open Access Journals (Sweden)

    Brandon P. Lucke-Wold

    2016-04-01

    Full Text Available Aneurysmal subarachnoid hemorrhage (SAH can lead to devastating outcomes including vasospasm, cognitive decline, and even death. Currently, treatment options are limited for this potentially life threatening injury. Recent evidence suggests that neuroinflammation plays a critical role in injury expansion and brain damage. Red blood cell breakdown products can lead to the release of inflammatory cytokines that trigger vasospasm and tissue injury. Preclinical models have been used successfully to improve understanding about neuroinflammation following aneurysmal rupture. The focus of this review is to provide an overview of how neuroinflammation relates to secondary outcomes such as vasospasm after aneurysmal rupture and to critically discuss pharmaceutical agents that warrant further investigation for the treatment of subarachnoid hemorrhage. We provide a concise overview of the neuroinflammatory pathways that are upregulated following aneurysmal rupture and how these pathways correlate to long-term outcomes. Treatment of aneurysm rupture is limited and few pharmaceutical drugs are available. Through improved understanding of biochemical mechanisms of injury, novel treatment solutions are being developed that target neuroinflammation. In the final sections of this review, we highlight a few of these novel treatment approaches and emphasize why targeting neuroinflammation following aneurysmal subarachnoid hemorrhage may improve patient care. We encourage ongoing research into the pathophysiology of aneurysmal subarachnoid hemorrhage, especially in regards to neuroinflammatory cascades and the translation to randomized clinical trials.

  2. Pediatric intracranial aneurysms.

    Science.gov (United States)

    Tripathy, L N; Singh, S N

    2009-01-01

    The incidence of subarachnoid haemorrhage from intracranial aneurysms in the paediatric age group is extremely rare. Interestingly, occurrence of vasospasm has been reported to be less in comparison to the adults. Both coiling and clipping have been advocated in selected cases. Because of the thinness of the wall of the arteries, utmost care should be taken while handling these arteries during surgery. The overall results of surgery in children have been reported to be better than their adult counterparts. We present four such cases from our own experience. All these children were operated upon, where the solitary aneurysm in each case was clipped and all of them made a good recovery.

  3. Seismic response analysis of arch dam-water-rock foundation systems

    Institute of Scientific and Technical Information of China (English)

    杜修力; 王进廷

    2004-01-01

    The effect of water compressibility on the seismic responses of arch dams is not well understood. In this paper, a numerical model is developed with rigorous representation of the dynamic interaction between arch dam-waterrock foundation. The model is applied to the seismic response analysis of an arch dam with a height of 292m designed to a seismic intensity of Ⅸ. It is shown that consideration of the water compressibility clearly decreases the stress responses at key positions of the dam, while the added mass model gives a conservative estimate.

  4. Use of the Structure of Blood Vessel for Detection of Brain Aneurysm and Route Search to Brain Aneurysm

    Directory of Open Access Journals (Sweden)

    Toshihide Miyagi

    2013-08-01

    Full Text Available In this research, we constructed functions that are necessary for the operation simulation system which assists medical students to inhibit brain aneurysm from exploding. The system reported in this paper is "detection of blood vessels", "detection of brain aneurysm" and "route planning to brain aneurysm". Not only the detection method but also the method to reduce the miss detection is realized for the detection of blood vessel. Finally, the future work will be shown including construction of head model consisting of artery, vein, brain and cranium.

  5. Pulsatile blood flow in Abdominal Aortic Aneurysms

    Science.gov (United States)

    Salsac, Anne-Virginie; Lasheras, Juan C.; Singel, Soeren; Varga, Chris

    2001-11-01

    We discuss the results of combined in-vitro laboratory measurements and clinical observations aimed at determining the effect that the unsteady wall shear stresses and the pressure may have on the growth and eventual rupturing of an Abdominal Aortic Aneurysm (AAA), a permanent bulging-like dilatation occurring near the aortic bifurcation. In recent years, new non-invasive techniques, such as stenting, have been used to treat these AAAs. However, the development of these implants, aimed at stopping the growth of the aneurysm, has been hampered by the lack of understanding of the effect that the hemodynamic forces have on the growth mechanism. Since current in-vivo measuring techniques lack the precision and the necessary resolution, we have performed measurements of the pressure and shear stresses in laboratory models. The models of the AAA were obtained from high resolution three-dimensional CAT/SCANS performed in patients at early stages of the disease. Preliminary DPIV measurements show that the pulsatile blood flow discharging into the cavity of the aneurysm leads to large spikes of pressure and wall shear stresses near and around its distal end, indicating a possible correlation between the regions of high wall shear stresses and the observed location of the growth of the aneurysm.

  6. Tympanic ossicles and pharyngeal arches.

    Science.gov (United States)

    Whyte, J; Cisneros, A; Yus, C; Fraile, J; Obón, J; Vera, A

    2009-02-01

    We have performed a study on 11 human embryos regarding the development of the tympanic ossicles and their relationship with the first pharyngeal arch. After performing measurements to date the embryos and foetuses chronologically, we performed a meticulous dissection of the temporal bones. Subsequently, they were fixed in 10% formol, decalcified with 2% nitric acid, embedded in Paraplast, sectioned in 7-mm sequences and stained with Martin's trichrome technique. In the 21- and 24-mm cranium-raquis (CR) length human embryos, we have observed the head of the malleus and the body of the incus close to Meckel's cartilage, in addition to the handle of the malleus, the long limb of the incus and the stapes. Between them there was a mesenchymal band inside the primordium of the tympanic cavity. In the 27-mm CR embryo, the various components of the malleus and incus were fusing, and in the 30-mm CR embryo the union was complete. From our observations, we can conclude that the malleus and the incus are derived from the first and second pharyngeal arches.

  7. Morphological and hemodynamic analysis of mirror posterior communicating artery aneurysms.

    Directory of Open Access Journals (Sweden)

    Jinyu Xu

    Full Text Available BACKGROUND AND PURPOSE: Hemodynamic factors are commonly believed to play an important role in the pathogenesis, progression, and rupture of cerebral aneurysms. In this study, we aimed to identify significant hemodynamic and morphological parameters that discriminate intracranial aneurysm rupture status using 3-dimensional-angiography and computational fluid dynamics technology. MATERIALS AND METHODS: 3D-DSA was performed in 8 patients with mirror posterior communicating artery aneurysms (Pcom-MANs. Each pair was divided into ruptured and unruptured groups. Five morphological and three hemodynamic parameters were evaluated for significance with respect to rupture. RESULTS: The normalized mean wall shear stress (WSS of the aneurysm sac in the ruptured group was significantly lower than that in the unruptured group (0.52±0.20 versus 0.81±0.21, P = .012. The percentage of the low WSS area in the ruptured group was higher than that in the unruptured group (4.11±4.66% versus 0.02±0.06%, P = .018. The AR was 1.04±0.21 in the ruptured group, which was significantly higher than 0.70±0.17 in the unruptured group (P = .012. By contrast, parameters that had no significant differences between the two groups were OSI (P = .674, aneurysm size (P = .327, size ratio (P = .779, vessel angle (P = 1.000 and aneurysm inclination angle (P = 1.000. CONCLUSIONS: Pcom-MANs may be a useful disease model to investigate possible causes of aneurysm rupture. The ruptured aneurysms manifested lower WSS, higher percentage of low WSS area, and higher AR, compared with the unruptured one. And hemodynamics is as important as morphology in discriminating aneurysm rupture status.

  8. Interleukin-6 as a Prognostic Biomarker in Ruptured Intracranial Aneurysms.

    Directory of Open Access Journals (Sweden)

    Hung-Wen Kao

    Full Text Available Interleukin-6 (IL-6, a proinflammatory cytokine, was found to surge in the cerebral spinal fluid after aneurysmal subarachnoid hemorrhage (SAH. We hypothesized that the plasma level of IL-6 could be an independent biomarker in predicting clinical outcome of patients with ruptured intracranial aneurysm.We prospectively included 53 consecutive patients treated with platinum coil embolization of the ruptured intracranial aneurysm. Plasma IL-6 levels were measured in the blood samples at the orifices of the aneurysms and from peripheral veins. The outcome measure was the modified Rankin Scale one month after SAH. Multiple logistic regression analyses were used to evaluate the associations between the plasma IL-6 levels and the neurological outcome.Significant risk factors for the poor outcome were old age, low Glasgow Coma Scale (GCS on day 0, high Fisher grades, and high aneurysmal and venous IL-6 levels in univariate analyses. Aneurysmal IL-6 levels showed modest to moderate correlations with GCS on day 0, vasospasm grade and Fisher grade. A strong correlation was found between the aneurysmal and the corresponding venous IL-6 levels (ρ = 0.721; P<0.001. In the multiple logistic regression models, the poor 30-day mRS was significantly associated with high aneurysmal IL-6 level (OR, 17.97; 95% CI, 1.51-214.33; P = 0.022 and marginally associated with high venous IL-6 level (OR, 12.71; 95% CI, 0.90-180.35; P = 0.022 after adjusting for dichotomized age, GCS on day 0, and vasospasm and Fisher grades.The plasma level of IL-6 is an independent prognostic biomarker that could be used to aid in the identification of patients at high-risk of poor neurological outcome after rupture of the intracranial aneurysm.

  9. Mirror aneurysms : a reflection on natural history

    NARCIS (Netherlands)

    Meissner, Irene; Torner, James; Huston III, John; Rajput, Michele L.; Wiebers, David O.; Jones, Lyell K.; Brown, Robert D.; Groen, Rob

    2012-01-01

    OBJECT: Investigators conducting the International Study of Unruptured Intracranial Aneurysms, sponsored by the National Institutes of Health, sought to evaluate predictors of future hemorrhage in patients who had unruptured mirror aneurysms. These paired aneurysms in bilateral arterial positions mi

  10. Morphological and Hemodynamic Discriminators for Rupture Status in Posterior Communicating Artery Aneurysms.

    Directory of Open Access Journals (Sweden)

    Nan Lv

    Full Text Available The conflicting findings of previous morphological and hemodynamic studies on intracranial aneurysm rupture may be caused by the relatively small sample sizes and the variation in location of the patient-specific aneurysm models. We aimed to determine the discriminators for aneurysm rupture status by focusing on only posterior communicating artery (PCoA aneurysms.In 129 PCoA aneurysms (85 ruptured, 44 unruptured, clinical, morphological and hemodynamic characteristics were compared between the ruptured and unruptured cases. Multivariate logistic regression analysis was performed to determine the discriminators for rupture status of PCoA aneurysms.While univariate analyses showed that the size of aneurysm dome, aspect ratio (AR, size ratio (SR, dome-to-neck ratio (DN, inflow angle (IA, normalized wall shear stress (NWSS and percentage of low wall shear stress area (LSA were significantly associated with PCoA aneurysm rupture status. With multivariate analyses, significance was only retained for higher IA (OR = 1.539, p < 0.001 and LSA (OR = 1.393, p = 0.041.Hemodynamics and morphology were related to rupture status of intracranial aneurysms. Higher IA and LSA were identified as discriminators for rupture status of PCoA aneurysms.

  11. Occlusal stability in shortened dental arches.

    Science.gov (United States)

    Witter, D J; Creugers, N H; Kreulen, C M; de Haan, A F

    2001-02-01

    Shortened dental arches consisting of anterior and premolar teeth have been shown to meet oral functional demands. However, the occlusal stability may be at risk as a result of tooth migration. The aim of this nine-year study was to investigate occlusal stability in shortened dental arches as a function over time. Occlusal stability indicators were: 'interdental spacing', 'occlusal contacts of anterior teeth in Intercuspal Position', 'overbite', 'occlusal tooth wear', and 'alveolar bone support'. Subjects with shortened dental arches (n = 74) were compared with subjects with complete dental arches (controls, n = 72). Repeated-measurement regression analyses were applied to assess age-dependent variables in the controls and to relate the occlusal changes to the period of time since the treatment that led to the shortened dental arches. Compared with complete dental arches, shortened dental arches had similar overbite and occlusal tooth wear. They showed more interdental spacing in the premolar regions, more anterior teeth in occlusal contact, and lower alveolar bone scores. Since the differences remained constant over time, we conclude that shortened dental arches can provide long-term occlusal stability. Occlusal changes were self-limiting, indicating a new occlusal equilibrium.

  12. Unoperated aortic aneurysm

    DEFF Research Database (Denmark)

    Perko, M J; Nørgaard, M; Herzog, T M;

    1995-01-01

    From 1984 to 1993, 1,053 patients were admitted with aortic aneurysm (AA) and 170 (15%) were not operated on. The most frequent reason for nonoperative management was presumed technical inoperability. Survivals for patients with thoracic, thoracoabdominal, and abdominal AA were comparable...... hypertension were predictive of mortality, whereas...

  13. Visualization of soil arching in flexible piled embankments

    Indian Academy of Sciences (India)

    Tuğba Eskışar

    2015-10-01

    Piled embankments rely on soil arching, but, when geogrid reinforcements are used, membrane action within the reinforcement contributes to load distribution. The arching of soil in unreinforced and reinforced piled embankments is evaluated in this study. A small-scale test apparatus is used to model the settlement up to 5 mm in an embankment with four pile elements. Visual inspection of the soil settlement and soil-reinforcement interaction is important to explain the mechanism of arching. In this study, X-ray Computed Tomography (CT) method was used as a non-destructive technique. The arching of soil between the piles was observed in the case of rigid piles and in the case of flexible piles with grid type of reinforcement. The load carrying capacity increased up to 33% in the case of geogrid reinforcement, and the differential settlement decreased around 35%, proving the efficiency of piled embankments with geogrid reinforcements. It is also shown that, using X-ray CT method and visualization techniques provides a better understanding of soil behavior in a reinforced embankment with the flexible pile foundation system.

  14. ArchDB 2014: structural classification of loops in proteins

    Science.gov (United States)

    Bonet, Jaume; Planas-Iglesias, Joan; Garcia-Garcia, Javier; Marín-López, Manuel A.; Fernandez-Fuentes, Narcis; Oliva, Baldo

    2014-01-01

    The function of a protein is determined by its three-dimensional structure, which is formed by regular (i.e. β-strands and α-helices) and non-periodic structural units such as loops. Compared to regular structural elements, non-periodic, non-repetitive conformational units enclose a much higher degree of variability—raising difficulties in the identification of regularities, and yet represent an important part of the structure of a protein. Indeed, loops often play a pivotal role in the function of a protein and different aspects of protein folding and dynamics. Therefore, the structural classification of protein loops is an important subject with clear applications in homology modelling, protein structure prediction, protein design (e.g. enzyme design and catalytic loops) and function prediction. ArchDB, the database presented here (freely available at http://sbi.imim.es/archdb), represents such a resource and has been an important asset for the scientific community throughout the years. In this article, we present a completely reworked and updated version of ArchDB. The new version of ArchDB features a novel, fast and user-friendly web-based interface, and a novel graph-based, computationally efficient, clustering algorithm. The current version of ArchDB classifies 149,134 loops in 5739 classes and 9608 subclasses. PMID:24265221

  15. Arch Venture Partners' investment considerations for CBRNE products and opportunities

    Science.gov (United States)

    Crandell, K.; Lazarus, S.; Gardner, P. J.

    2008-04-01

    ARCH is interested in building leading, highly-valued companies from leading research. Toward that end we value innovations created by the leading researchers in the world, many of which are funded to solve critical scientific challenges including those in the instrumentation and CBRNE area. The most important CBRNE innovations we have seen at ARCH are breakthroughs involving significant unaddressed technology risk and have the potential for broad proprietary intellectual property as a result. The model ARCH has evolved in instrumentation is to look for a breakthrough innovation, with strong intellectual property and continue to strengthen the patent estate through the life of the company. ARCH looks to build companies around leading interdisciplinary scientific and engineering teams, and we favor platform technology that can be applied to multiple market applications both commercial and government. As part of a strategy to build a great company, addressing important CBRNE challenges can help a company strengthen its technical team and its IP estate. This supports a focus on early low volume markets on the way toward addressing a fuller portfolio of applications. Experienced Venture Capitalists can help this process by identifying important executive talent, partners and applications, offering financial syndication strength, and helping shape the company's strategy to maximize the ultimate value realized.

  16. A Novel Thin Film Nitinol Covered Neurovascular Stent Significantly Decreases Intra-Aneurysmal Flow In Vitro

    Science.gov (United States)

    Chun, Youngjae; Hur, Soojung; Shayan, Mahdis; Kealey, Colin; Levi, Daniel; Mohanchandra, Kp; di Carlo, Dino; Carman, Gregory

    2013-11-01

    A novel thin film nitinol (TFN) stent has been developed to promote aneurysm quiescence by diminishing flow across the aneurysm's neck. Laboratory aneurysm models were used to assess the flow changes produced by stents covered with different patterns of TFN. Flow diversion stents were constructed by covering Wingspan stents (Boston Scientific, DxL:4x20mm) with TFNs (i.e., 77 and 82 percent porosity). The flow changes that occur after deployment of two different porous TFN covered stent in intracranial aneurysm models were evaluated in vitro. The 82 percent porous TFN covered stent reduced the intra-aneurysmal mean flow velocity by 86.42 percent, while a 77 percent porous TFN covered stent reduced to intra-aneurysmal mean flow velocity to 93.44 percent compared to a nonstented model. Local wall shear rates were also significantly reduced in wide-neck aneurysm model (i.e., 97.52 - 98.92 percent) with TFN stent placement. The results showed that TFN covered stents significantly reduced intra-aneurysmal flow velocity magnitudes and local wall shear rates. This suggests that TFN covered stents with both 77 and 82 percent porosity have great potential to promote thrombosis in both wide-necked and fusiform aneurysm sacs.

  17. Thoracic aortic aneurysm: A rare cause of elevated hemidiaphragm

    Directory of Open Access Journals (Sweden)

    Md Arshad Ejazi

    2016-01-01

    Full Text Available Phrenic nerve palsy causing hemidiaphragm paralysis is a very uncommon feature of thoracic aortic aneurysm. In one case, a 30 year male complained of chronic dull aching chest pain, and hoarseness of voice; posteroanterior view chest radiograph revealed large spherical radiopacity on the left upper lung zone with smooth lobulated margin with elevated left hemidiaphragm. On Colour Doppler sonography, lesion was anechoic on gray scale sonography but on Doppler analysis revealed intense internal vascularity within it with characteristic "Ying Yang" sign. The finding favor the vascular origin of the lesion and a diagnosis of an arterial aneurysm was made Contrast-enhanced computed tomography (CT of the thorax revealed a large well defined spherical lesion of 8 × 10 cm size with smooth well defined margin arising from the aortic arch and attenuation of impending rupture or dissection were lesion on immediate post contrast and delayed scan was similar to that of aorta. Left hemidiaphragm elevation was explained by the gross mass effect of the aneurysm causing right phrenic nerve palsy.

  18. MicroRNAs, fibrotic remodeling, and aortic aneurysms

    Science.gov (United States)

    Milewicz, Dianna M.

    2012-01-01

    Aortic aneurysms are a common clinical condition that can cause death due to aortic dissection or rupture. The association between aortic aneurysm pathogenesis and altered TGF-β signaling has been the subject of numerous investigations. Recently, a TGF-β–responsive microRNA (miR), miR-29, has been identified to play a role in cellular phenotypic modulation during aortic development and aging. In this issue of JCI, Maegdefessel and colleagues demonstrate that decreasing the levels of miR-29b in the aortic wall can attenuate aortic aneurysm progression in two different mouse models of abdominal aortic aneurysms. This study highlights the relevance of miR-29b in aortic disease but also raises questions about its specific role. PMID:22269322

  19. Velocity profile and wall shear stress of saccular aneurysms at the anterior communicating artery.

    Science.gov (United States)

    Yamaguchi, Ryuhei; Ujiie, Hiroshi; Haida, Sayaka; Nakazawa, Nobuhiko; Hori, Tomokatsu

    2008-01-01

    It has recently been shown that the aspect ratio (dome/neck) of an aneurysm correlates well with intraaneurysmal blood flow. Aneurysms with an aspect ratio larger than 1.6 carry a higher risk of rupture. We examined the effect of aspect ratio (AR) on intra-aneurysmal flow using experimental models. Flow visualization with particle imaging velocimetry and measurement of wall shear stress using laser Doppler anemometry were performed on three different aneurysm models: AR 0.5, 1.0, and 2.0. Intraaneurysmal flow consists of inflow, circulation, and outflow. Rapid inflow impinged on the distal neck creating a stagnant point. Rapid flow and maximum wall shear stress were observed in the vicinity of the stagnant point. By changing the Reynold's number, the stagnant point moved. By increasing the AR of the aneurysm, vortices inside the aneurysm sac closed and very slow flow was observed, resulting in very low shear stress markedly at a Reynold's number of 250, compatible with the diastolic phase. In the aneurysm model AR 2.0, both rapid flow at the neck and vortices inside the aneurysm are sufficient to activate platelets, making a thrombus that may anchor on the dome where very slow flow takes place. Hemodynamics in aneurysms larger than AR 2.0 definitely contribute to thrombus formation.

  20. Computational hemodynamic study of intracranial aneurysms coexistent with proximal artery stenosis

    Science.gov (United States)

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

    2012-03-01

    Intracranial aneurysms and artery stenosis are vascular diseases with different pathophysiological characteristics. However, although unusual, aneurysms may coexist in up to 5% of patients with stenotic plaque, according to a previous study. Another study showed that incidental detection of cerebral aneurysm in the same cerebral circulation as the stenotic plaque was less than 2%. Patients with concomitant carotid artery stenosis and unruptured intracranial aneurysms pose a difficult management decision for the physician. Case reports showed patients who died due to aneurysm rupture months after endarterectomy but before aneurysm clipping, while others did not show any change in the aneurysm after plaque removal, having optimum outcome after aneurysm coiling. The purpose of this study is to investigate the intraaneurysmal hemodynamic changes before and after treatment of stenotic plaque. Idealized models were constructed with different stenotic grade, distance and relative position to the aneurysm. Digital removal of the stenotic plaque was performed in the reconstructed model of a patient with both pathologies. Computational fluid dynamic simulations were performed using a finite element method approach. Blood velocity field and hemodynamic forces were recorded and analyzed. Changes in the flow patterns and wall shear stress values and distributions were observed in both ideal and image-based models. Detailed investigation of wall shear stress distributions in patients with both pathologies is required to make the best management decision.

  1. Persistent fifth arch anomalies - broadening the spectrum to include a variation of double aortic arch vascular ring

    Energy Technology Data Exchange (ETDEWEB)

    Newman, Beverley; Chan, Frandics [Stanford Children' s Hospital and Stanford University, Department of Radiology, Stanford, CA (United States); Hanneman, Kate [University of Toronto, Department of Medical Imaging, Toronto, ON (Canada)

    2016-12-15

    Fifth arch anomalies are rare and complex and frequently misdiagnosed or mistaken for other entities. We report a double arch vascular ring that is thought to consist of right fourth arch and left fifth arch components, a previously undescribed persistent fifth arch variant. The currently recognized spectrum and classification of fifth arch vascular anomalies are expanded along with illustrative images to justify the proposed changes. Reviewing and expanding the classification of fifth arch anomalies to include a double arch ring variant will promote recognition, correct diagnosis and appropriate management of these anomalies. (orig.)

  2. CT of thoracic aortic aneurysms.

    Science.gov (United States)

    Posniak, H V; Olson, M C; Demos, T C; Benjoya, R A; Marsan, R E

    1990-09-01

    Aneurysms of the thoracic aorta are most often the result of arteriosclerotic disease. Other causes include degeneration of the medial layer of the aortic wall, either idiopathically or due to genetic disorders such as Marfan syndrome; aortic dissection; trauma; syphilis and other bacterial infection; noninfective aortitis; and congenital anomaly. We review normal anatomy of the aorta and discuss our technique and interpretation of computed tomography (CT) in the evaluation of the thoracic aorta. We illustrate the CT appearance of different types of aortic aneurysms as well as discuss the use of CT for assessing complications of aneurysms, for postoperative follow-up, and in the differentiation of aortic aneurysm from a paraaortic mass.

  3. CREATIVITY METHODS IN TEACHING THE ARCH-DESIGN STUDIO

    Directory of Open Access Journals (Sweden)

    EIGBEONAN Andrew B.

    2013-07-01

    Full Text Available The aim of this paper is to search and find methods of fostering creativity or ideas relating to creativity in teaching the arch-design studio. Teaching creativity through its methods will be making the students grounded in designing with creativity ideas and therefore we can have professionals that design and build with satisfaction, safety and complementary. It means we can have real buildings and places that satisfy our clients, the society and in harmony with the environment. Although there are similarities in the curricula of training architects all over the world, but educators go about it in their own convenient and suitable ways and styles. The ideas of creativity have been part of architecture from the onset, but are not deligently applied and also not formally incorporated in the curricula of training. The topic is also very relevant and timely as arch-educators and other stakeholders are of the opinion that something has to be done to improve the ways and methods of training architects, especially the teaching of the arch-design studio with regards to creativity. Through exploration of literature and interviews (physical and telephone call this paper finds methods of stimulating creativity ideas in the teaching of arch-design studio. Some of the methods of motivating creativity found in teaching the arch-design studio are: analogy, metaphors, biomimicry, brainstorming, attribute listing, mental map, TRIZ, restrictions, charrette, browsing, excursions, focus groups, other peoples viewpoints, using crazy ideas, using experts, visualizing a goal, working with dreams and images and giving students design tools such as drawings CAD and model making.

  4. Correlation Between Maxillary Central Incisor Crown Morphology And Mandibular Dental Arch Form In Normal Occlusion Subjects

    OpenAIRE

    Paranhos, Luiz Renato; Lima,Carolina Souto; Silva,Ricardo Henrique Alves da; Daruge Júnior,Eduardo; Torres,Fernando Cesar

    2012-01-01

    The aim of this study was to evaluate the correlation between the morphology of the mandibular dental arch and the maxillary central incisor crown. Cast models from 51 Caucasian individuals, older than 15 years, with optimal occlusion, no previous orthodontic treatment, featuring 4 of the 6 keys to normal occlusion by Andrews (the first being mandatory) were observed. The models were digitalized using a 3D scanner, and images of the maxillary central incisor and mandibular dental arch were ob...

  5. Continuum analysis of common branching patterns in the human arch of the aorta.

    Science.gov (United States)

    Zamir, M; Sinclair, P

    1990-01-01

    A model is proposed for describing common variations in the arrangement of branches on the arch of the human aorta, and the model is used to analyze data from 123 human arches. The analysis allows the observed variations to fall freely along a continuous spectrum, rather than be confined to discrete categories as is commonly done at present. The results thus describe these variations in a more natural way and throw some new light on their likely source.

  6. The effect of flow recirculation on abdominal aortic aneurysm

    Science.gov (United States)

    Taib, Ishkrizat; Amirnordin, Shahrin Hisham; Madon, Rais Hanizam; Mustafa, Norrizal; Osman, Kahar

    2012-06-01

    The presences of flow recirculation at the abdominal aortic aneurysm (AAA) region yield the unpredictable failure of aneurismal wall. The failure of the aneurismal wall is closely related to the hemodynamic factor. Hemodynamic factor such as pressure and velocity distribution play a significance role of aneurysm growth and rupture. By using the computational approach, the influence of hemodynamic factor is investigated using computational fluid dynamic (CFD) method on the virtual AAA model. The virtual 3D AAAs model was reconstructed from Spiral Computed Tomography scan (CT-scan). The blood flow is assumed as being transient, laminar and Newtonian within a rigid section of the vessel. The blood flow also driven by an imposed of pressure gradient in the form of physiological waveform. The pulsating blood flow is also considered in this simulation. The results on pressure distribution and velocity profile are analyzed to interpret the behaviour of flow recirculation. The results show the forming of vortices is seen at the aneurysm bulge. This vortices is form at the aneurysm region then destroyed rapidly by flow recirculation. Flow recirculation is point out much higher at distal end of aneurysm closed to iliac bifurcation. This phenomenon is managed to increase the possibility of aneurysm growth and rupture.

  7. The Role of Arch Compression and Metatarsophalangeal Joint Dynamics in Modulating Plantar Fascia Strain in Running.

    Directory of Open Access Journals (Sweden)

    Kirsty A McDonald

    Full Text Available Elastic energy returned from passive-elastic structures of the lower limb is fundamental in lowering the mechanical demand on muscles during running. The purpose of this study was to investigate the two length-modulating mechanisms of the plantar fascia, namely medial longitudinal arch compression and metatarsophalangeal joint (MPJ excursion, and to determine how these mechanisms modulate strain, and thus elastic energy storage/return of the plantar fascia during running. Eighteen runners (9 forefoot and 9 rearfoot strike performed three treadmill running trials; unrestricted shod, shod with restricted arch compression (via an orthotic-style insert, and barefoot. Three-dimensional motion capture and ground reaction force data were used to calculate lower limb kinematics and kinetics including MPJ angles, moments, powers and work. Estimates of plantar fascia strain due to arch compression and MPJ excursion were derived using a geometric model of the arch and a subject-specific musculoskeletal model of the plantar fascia, respectively. The plantar fascia exhibited a typical elastic stretch-shortening cycle with the majority of strain generated via arch compression. This strategy was similar in fore- and rear-foot strike runners. Restricting arch compression, and hence the elastic-spring function of the arch, was not compensated for by an increase in MPJ-derived strain. In the second half of stance the plantar fascia was found to transfer energy between the MPJ (energy absorption and the arch (energy production during recoil. This previously unreported energy transfer mechanism reduces the strain required by the plantar fascia in generating useful positive mechanical work at the arch during running.

  8. The Role of Arch Compression and Metatarsophalangeal Joint Dynamics in Modulating Plantar Fascia Strain in Running.

    Science.gov (United States)

    McDonald, Kirsty A; Stearne, Sarah M; Alderson, Jacqueline A; North, Ian; Pires, Neville J; Rubenson, Jonas

    2016-01-01

    Elastic energy returned from passive-elastic structures of the lower limb is fundamental in lowering the mechanical demand on muscles during running. The purpose of this study was to investigate the two length-modulating mechanisms of the plantar fascia, namely medial longitudinal arch compression and metatarsophalangeal joint (MPJ) excursion, and to determine how these mechanisms modulate strain, and thus elastic energy storage/return of the plantar fascia during running. Eighteen runners (9 forefoot and 9 rearfoot strike) performed three treadmill running trials; unrestricted shod, shod with restricted arch compression (via an orthotic-style insert), and barefoot. Three-dimensional motion capture and ground reaction force data were used to calculate lower limb kinematics and kinetics including MPJ angles, moments, powers and work. Estimates of plantar fascia strain due to arch compression and MPJ excursion were derived using a geometric model of the arch and a subject-specific musculoskeletal model of the plantar fascia, respectively. The plantar fascia exhibited a typical elastic stretch-shortening cycle with the majority of strain generated via arch compression. This strategy was similar in fore- and rear-foot strike runners. Restricting arch compression, and hence the elastic-spring function of the arch, was not compensated for by an increase in MPJ-derived strain. In the second half of stance the plantar fascia was found to transfer energy between the MPJ (energy absorption) and the arch (energy production during recoil). This previously unreported energy transfer mechanism reduces the strain required by the plantar fascia in generating useful positive mechanical work at the arch during running.

  9. Fluid-structure interaction of a patient-specific abdominal aortic aneurysm treated with an endovascular stent-graft.

    LENUS (Irish Health Repository)

    Molony, David S

    2009-01-01

    BACKGROUND: Abdominal aortic aneurysms (AAA) are local dilatations of the infrarenal aorta. If left untreated they may rupture and lead to death. One form of treatment is the minimally invasive insertion of a stent-graft into the aneurysm. Despite this effective treatment aneurysms may occasionally continue to expand and this may eventually result in post-operative rupture of the aneurysm. Fluid-structure interaction (FSI) is a particularly useful tool for investigating aneurysm biomechanics as both the wall stresses and fluid forces can be examined. METHODS: Pre-op, Post-op and Follow-up models were reconstructed from CT scans of a single patient and FSI simulations were performed on each model. The FSI approach involved coupling Abaqus and Fluent via a third-party software - MpCCI. Aneurysm wall stress and compliance were investigated as well as the drag force acting on the stent-graft. RESULTS: Aneurysm wall stress was reduced from 0.38 MPa before surgery to a value of 0.03 MPa after insertion of the stent-graft. Higher stresses were seen in the aneurysm neck and iliac legs post-operatively. The compliance of the aneurysm was also reduced post-operatively. The peak Post-op axial drag force was found to be 4.85 N. This increased to 6.37 N in the Follow-up model. CONCLUSION: In a patient-specific case peak aneurysm wall stress was reduced by 92%. Such a reduction in aneurysm wall stress may lead to shrinkage of the aneurysm over time. Hence, post-operative stress patterns may help in determining the likelihood of aneurysm shrinkage post EVAR. Post-operative remodelling of the aneurysm may lead to increased drag forces.

  10. Fluid-structure interaction of a patient-specific abdominal aortic aneurysm treated with an endovascular stent-graft

    Directory of Open Access Journals (Sweden)

    McGloughlin Tim M

    2009-10-01

    Full Text Available Abstract Background Abdominal aortic aneurysms (AAA are local dilatations of the infrarenal aorta. If left untreated they may rupture and lead to death. One form of treatment is the minimally invasive insertion of a stent-graft into the aneurysm. Despite this effective treatment aneurysms may occasionally continue to expand and this may eventually result in post-operative rupture of the aneurysm. Fluid-structure interaction (FSI is a particularly useful tool for investigating aneurysm biomechanics as both the wall stresses and fluid forces can be examined. Methods Pre-op, Post-op and Follow-up models were reconstructed from CT scans of a single patient and FSI simulations were performed on each model. The FSI approach involved coupling Abaqus and Fluent via a third-party software - MpCCI. Aneurysm wall stress and compliance were investigated as well as the drag force acting on the stent-graft. Results Aneurysm wall stress was reduced from 0.38 MPa before surgery to a value of 0.03 MPa after insertion of the stent-graft. Higher stresses were seen in the aneurysm neck and iliac legs post-operatively. The compliance of the aneurysm was also reduced post-operatively. The peak Post-op axial drag force was found to be 4.85 N. This increased to 6.37 N in the Follow-up model. Conclusion In a patient-specific case peak aneurysm wall stress was reduced by 92%. Such a reduction in aneurysm wall stress may lead to shrinkage of the aneurysm over time. Hence, post-operative stress patterns may help in determining the likelihood of aneurysm shrinkage post EVAR. Post-operative remodelling of the aneurysm may lead to increased drag forces.

  11. In-Plane Elastic Buckling of Arch

    Institute of Scientific and Technical Information of China (English)

    剧锦三; 郭彦林

    2002-01-01

    The in-plane elastic buckling behavior of arches is investigated using a new finite-element approach for the nonlinear analysis. The linear buckling, nonlinear primary buckling, and secondary bifurcation buckling behavior of arches are compared taking into account the large deformation and the effects of initial geometric imperfections or perturbations. The theoretical investigation emphasizes the nonlinear secondary bifurcation buckling behavior for a full span uniformly distributed load. The efficiency of compact method for tracing secondary buckling path is shown through several examples. Finally, a new structural design, which prevents the secondary bifurcation buckling by adding some crossed cables across the arch, is proposed to improve the limit load carrying capacity.

  12. The 'Sphere': A Dedicated Bifurcation Aneurysm Flow-Diverter Device.

    Science.gov (United States)

    Peach, Thomas; Cornhill, J Frederick; Nguyen, Anh; Riina, Howard; Ventikos, Yiannis

    2014-01-01

    We present flow-based results from the early stage design cycle, based on computational modeling, of a prototype flow-diverter device, known as the 'Sphere', intended to treat bifurcation aneurysms of the cerebral vasculature. The device is available in a range of diameters and geometries and is constructed from a single loop of NITINOL(®) wire. The 'Sphere' reduces aneurysm inflow by means of a high-density, patterned, elliptical surface that partially occludes the aneurysm neck. The device is secured in the healthy parent vessel by two armatures in the shape of open loops, resulting in negligible disruption of parent or daughter vessel flow. The device is virtually deployed in six anatomically accurate bifurcation aneurysms: three located at the Basilar tip and three located at the terminus bifurcation of the Internal Carotid artery (at the meeting of the middle cerebral and anterior cerebral arteries). Both steady state and transient flow simulations reveal that the device presents with a range of aneurysm inflow reductions, with mean flow reductions falling in the range of 30.6-71.8% across the different geometries. A significant difference is noted between steady state and transient simulations in one geometry, where a zone of flow recirculation is not captured in the steady state simulation. Across all six aneurysms, the device reduces the WSS magnitude within the aneurysm sac, resulting in a hemodynamic environment closer to that of a healthy vessel. We conclude from extensive CFD analysis that the 'Sphere' device offers very significant levels of flow reduction in a number of anatomically accurate aneurysm sizes and locations, with many advantages compared to current clinical cylindrical flow-diverter designs. Analysis of the device's mechanical properties and deployability will follow in future publications.

  13. Ruptured abdominal aortic aneurysm.

    Science.gov (United States)

    Sachs, T; Schermerhorn, M

    2010-06-01

    Ruptured abdominal aortic aneurysm (AAA) continues to be one of the most lethal vascular pathologies we encounter. Its management demands prompt and efficient evaluation and repair. Open repair has traditionally been the mainstay of treatment. However, the introduction of endovascular techniques has altered the treatment algorithm for ruptured AAA in most major medical centers. We present recent literature and techniques for ruptured AAA and its surgical management.

  14. Inflammation and intracranial aneurysms: mechanisms of initiation, growth, and rupture

    Directory of Open Access Journals (Sweden)

    Peter S Amenta

    2015-06-01

    Full Text Available Outcomes following aneurysmal subarachnoid hemorrhage remain poor in many patients, despite advances in microsurgical and endovascular management. Consequently, considerable effort has been placed in determining the mechanisms of aneurysm formation, growth, and rupture. Various environmental and genetic factors are implicated as key components in the aneurysm pathogenesis. Currently, sufficient evidence exists to incriminate the inflammatory response as the common pathway leading to aneurysm generation and rupture. Central to this model is the interaction between the vessel wall and inflammatory cells. Dysfunction of the endothelium and vascular smooth muscle cells (VSMCs promotes a chronic pathological inflammatory response that progressively weakens the vessel wall. We review the literature pertaining to the cellular and chemical mechanisms of inflammation that contribute to aneurysm development. Hemodynamic stress and alterations in blood flow are discussed regarding their role in promoting chronic inflammation. Endothelial cell and VSMC dysfunction are examined concerning vascular remodeling. The contribution of inflammatory cytokines, especially tumor necrosis factor-α is illustrated. Inflammatory cell infiltration, particularly macrophage-mediated deterioration of vascular integrity, is reviewed. We discuss the inflammation as a means to determine aneurysms at greatest risk of rupture. Finally, future therapeutic implications of pharmacologic modulation of the inflammation are discussed.

  15. Growth of Intracranial Aneurysms Arised from Curved Vessels under the Influence of Elevated Wall Shear Stress ─ A Computer Simulation Study

    Science.gov (United States)

    Feng, Yixiang; Wada, Shigeo; Tsubota, Ken-Ichi; Yamaguchi, Takami

    Recent studies have suggested that long standing elevated wall shear stress might degenerate the arterial wall and be involved in the pathogenesis of intracranial aneurysm formation and development. The present study focuses on the interplay between the hemodynamic stresses, arterial wall degeneration and deformation. By constructing a computational model and examining the hypotheses that govern the rules to grow an intracranial aneurysm, we simulate the formation and development of intracranial aneurysms. The high wall shear stress is found to propagate towards the proximal and distal end of the formed aneurysm, which becomes the key factor for the expansion of wall degeneration and aneurysm progression. The development of aneurysm is influenced by the wall shear stress threshold, the Reynolds number and the rate of wall degeneration. Our preliminary results indicate that computer simulation can be used in the study of aneurysm mechanics and yields new insight into the mechanism of aneurysm pathophysiology.

  16. Determinant factors of Yemeni maxillary arch dimensions

    Directory of Open Access Journals (Sweden)

    Nabil Muhsen Al-Zubair

    2015-01-01

    Conclusion: Measurements of palatal depth and relationships of the canines to one another and to other teeth thus had the widest ranges, implying that these dimensions are the strongest determinants of maxillary arch size.

  17. Correlation between maxillary central incisor crown morphology and mandibular dental arch form in normal occlusion subjects.

    Science.gov (United States)

    Paranhos, Luiz Renato; Lima, Carolina Souto; da Silva, Ricardo Henrique Alves; Daruge Júnior, Eduardo; Torres, Fernando Cesar

    2012-01-01

    The aim of this study was to evaluate the correlation between the morphology of the mandibular dental arch and the maxillary central incisor crown. Cast models from 51 Caucasian individuals, older than 15 years, with optimal occlusion, no previous orthodontic treatment, featuring 4 of the 6 keys to normal occlusion by Andrews (the first being mandatory) were observed. The models were digitalized using a 3D scanner, and images of the maxillary central incisor and mandibular dental arch were obtained. These were printed and placed in an album below pre-set models of arches and dental crowns, and distributed to 12 dental surgeons, who were asked to choose which shape was most in accordance with the models and crown presented. The Kappa test was performed to evaluate the concordance among evaluators while the chi-square test was used to verify the association between the dental arch and central incisor morphology, at a 5% significance level. The Kappa test showed moderate agreement among evaluators for both variables of this study, and the chi-square test showed no significant association between tooth shape and mandibular dental arch morphology. It may be concluded that the use of arch morphology as a diagnostic method to determine the shape of the maxillary central incisor is not appropriate. Further research is necessary to assess tooth shape using a stricter scientific basis.

  18. Genetic and Epigenetic Regulation of Aortic Aneurysms

    Science.gov (United States)

    Kim, Ha Won

    2017-01-01

    Aneurysms are characterized by structural deterioration of the vascular wall leading to progressive dilatation and, potentially, rupture of the aorta. While aortic aneurysms often remain clinically silent, the morbidity and mortality associated with aneurysm expansion and rupture are considerable. Over 13,000 deaths annually in the United States are attributable to aortic aneurysm rupture with less than 1 in 3 persons with aortic aneurysm rupture surviving to surgical intervention. Environmental and epidemiologic risk factors including smoking, male gender, hypertension, older age, dyslipidemia, atherosclerosis, and family history are highly associated with abdominal aortic aneurysms, while heritable genetic mutations are commonly associated with aneurysms of the thoracic aorta. Similar to other forms of cardiovascular disease, family history, genetic variation, and heritable mutations modify the risk of aortic aneurysm formation and provide mechanistic insight into the pathogenesis of human aortic aneurysms. This review will examine the relationship between heritable genetic and epigenetic influences on thoracic and abdominal aortic aneurysm formation and rupture. PMID:28116311

  19. Complete interruption of the aortic arch

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Hak; Park, In Kyu; Lee, Won Hwa; Kim, Yong Joo; Kang, Duk Sik; Lee, Jong Tae [Kyungpook National University College of Medicine, Taegu (Korea, Republic of)

    1984-09-15

    Complete interrupture of the aortic arch is one of the least common cardiac malformation. In this condition, continuity between the ascending and descending protions of the aorta is not present, and the descending aorta is supplied through a reversing patent ductus arteriosus. In the majority of the patients a ventricular septal defect is present. Authors have experienced a case of the complete interruption of aortic arch, interruption between the left carotid and the left subclavian artery.

  20. 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.

  1. Tobacco smoking and aortic aneurysm

    DEFF Research Database (Denmark)

    Sode, Birgitte F; Nordestgaard, Børge G; Grønbæk, Morten

    2012-01-01

    General Population Study, respectively. According to the magnitude of the hazard ratios, tobacco consumption was the most important risk factor for hospitalization and death from aortic aneurysm, followed by male sex and hypertension in both cohorts. The population attributable risk of aortic aneurysm...... outcomes due to tobacco consumption was 64% and 47% in the Copenhagen City Heart Study and Copenhagen General Population Study, respectively, and ranked highest among population attributable risks of aortic aneurysm in both cohorts. The absolute 10-year risk for hospitalization or death from aortic......BACKGROUND: We determined the predictive power of tobacco smoking on aortic aneurysm as opposed to other risk factors in the general population. METHODS: We recorded tobacco smoking and other risk factors at baseline, and assessed hospitalization and death from aortic aneurysm in 15,072 individuals...

  2. Parallel multiscale simulations of a brain aneurysm

    Energy Technology Data Exchange (ETDEWEB)

    Grinberg, Leopold [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States); Fedosov, Dmitry A. [Institute of Complex Systems and Institute for Advanced Simulation, Forschungszentrum Jülich, Jülich 52425 (Germany); Karniadakis, George Em, E-mail: george_karniadakis@brown.edu [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States)

    2013-07-01

    Cardiovascular pathologies, such as a brain aneurysm, are affected by the global blood circulation as well as by the local microrheology. Hence, developing computational models for such cases requires the coupling of disparate spatial and temporal scales often governed by diverse mathematical descriptions, e.g., by partial differential equations (continuum) and ordinary differential equations for discrete particles (atomistic). However, interfacing atomistic-based with continuum-based domain discretizations is a challenging problem that requires both mathematical and computational advances. We present here a hybrid methodology that enabled us to perform the first multiscale simulations of platelet depositions on the wall of a brain aneurysm. The large scale flow features in the intracranial network are accurately resolved by using the high-order spectral element Navier–Stokes solver NεκTαr. The blood rheology inside the aneurysm is modeled using a coarse-grained stochastic molecular dynamics approach (the dissipative particle dynamics method) implemented in the parallel code LAMMPS. The continuum and atomistic domains overlap with interface conditions provided by effective forces computed adaptively to ensure continuity of states across the interface boundary. A two-way interaction is allowed with the time-evolving boundary of the (deposited) platelet clusters tracked by an immersed boundary method. The corresponding heterogeneous solvers (NεκTαr and LAMMPS) are linked together by a computational multilevel message passing interface that facilitates modularity and high parallel efficiency. Results of multiscale simulations of clot formation inside the aneurysm in a patient-specific arterial tree are presented. We also discuss the computational challenges involved and present scalability results of our coupled solver on up to 300 K computer processors. Validation of such coupled atomistic-continuum models is a main open issue that has to be addressed in

  3. Parallel multiscale simulations of a brain aneurysm.

    Science.gov (United States)

    Grinberg, Leopold; Fedosov, Dmitry A; Karniadakis, George Em

    2013-07-01

    Cardiovascular pathologies, such as a brain aneurysm, are affected by the global blood circulation as well as by the local microrheology. Hence, developing computational models for such cases requires the coupling of disparate spatial and temporal scales often governed by diverse mathematical descriptions, e.g., by partial differential equations (continuum) and ordinary differential equations for discrete particles (atomistic). However, interfacing atomistic-based with continuum-based domain discretizations is a challenging problem that requires both mathematical and computational advances. We present here a hybrid methodology that enabled us to perform the first multi-scale simulations of platelet depositions on the wall of a brain aneurysm. The large scale flow features in the intracranial network are accurately resolved by using the high-order spectral element Navier-Stokes solver εκαr . The blood rheology inside the aneurysm is modeled using a coarse-grained stochastic molecular dynamics approach (the dissipative particle dynamics method) implemented in the parallel code LAMMPS. The continuum and atomistic domains overlap with interface conditions provided by effective forces computed adaptively to ensure continuity of states across the interface boundary. A two-way interaction is allowed with the time-evolving boundary of the (deposited) platelet clusters tracked by an immersed boundary method. The corresponding heterogeneous solvers ( εκαr and LAMMPS) are linked together by a computational multilevel message passing interface that facilitates modularity and high parallel efficiency. Results of multiscale simulations of clot formation inside the aneurysm in a patient-specific arterial tree are presented. We also discuss the computational challenges involved and present scalability results of our coupled solver on up to 300K computer processors. Validation of such coupled atomistic-continuum models is a main open issue that has to be addressed in future

  4. Determination of wall tension in cerebral artery aneurysms by numerical simulation

    DEFF Research Database (Denmark)

    Isaksen, J.G.; Bazilevs, Y.; Kvamsdal, T.

    2008-01-01

    BACKGROUND AND PURPOSE: Cerebral artery aneurysms rupture when wall tension exceeds the strength of the wall tissue. At present, risk-assessment of unruptured aneurysms does not include evaluation of the lesions shape, yet clinical experience suggests that this is of importance. We aimed to develop...... a computational model for simulation of fluid-structure interaction in cerebral aneurysms based on patient specific lesion geometry, with special emphasis on wall tension. METHODS: An advanced isogeometric fluid-structure analysis model incorporating flexible aneurysm wall based on patient specific computed...... tomography angiogram images was developed. Variables used in the simulation model were retrieved from a literature review. RESULTS: The simulation results exposed areas of high wall tension and wall displacement located where aneurysms usually rupture. CONCLUSIONS: We suggest that analyzing wall tension...

  5. CFD-based Thrombotic Risk Assessment in Kawasaki Disease Patients with Coronary Artery Aneurysms

    Science.gov (United States)

    Sengupta, Dibyendu; Kung, Ethan; Kahn, Andrew; Burns, Jane; Marsden, Alison

    2012-11-01

    Coronary aneurysms occur in 25% of untreated Kawasaki Disease (KD) patients and put patients at increased risk for myocardial infarction and sudden death. Clinical guidelines recommend using aneurysm diameter >8 mm as the arbitrary criterion for treating with anti-coagulation therapy. This study uses patient-specific modeling to non-invasively determine hemodynamic parameters and quantify thrombotic risk. Anatomic models were constructed from CT angiographic image data from 5 KD aneurysm patients and one normal control. CFD simulations were performed to obtain hemodynamic data including WSS and particle residence times (PRT). Thrombosis was clinically observed in 4/9 aneurysmal coronaries. Thrombosed vessels required twice as many cardiac cycles (mean 8.2 vs. 4.2) for particles to exit, and had lower mean WSS (1.3 compared to 2.8 dynes/cm2) compared to vessels with non-thrombosed aneurysms of similar max diameter. 1 KD patient in the cohort with acute thrombosis had diameter < 8 mm. Regions of low WSS and high PRT predicted by simulations correlated with regions of subsequent thrombus formation. Thrombotic risk stratification for KD aneurysms may be improved by incorporating both hemodynamic and geometric quantities. Current clinical guidelines to assess patient risk based only on aneurysm diameter may be misleading. Further prospective study is warranted to evaluate the utility of patient-specific modeling in risk stratifying KD patients with coronary aneurysms. NIH R21.

  6. Inhibition of Receptor-Interacting Protein Kinase 1 with Necrostatin–1s ameliorates disease progression in elastase-induced mouse abdominal aortic aneurysm model

    Science.gov (United States)

    Wang, Qiwei; Zhou, Ting; Liu, Zhenjie; Ren, Jun; Phan, Noel; Gupta, Kartik; Stewart, Danielle M.; Morgan, Stephanie; Assa, Carmel; Kent, K. Craig; Liu, Bo

    2017-01-01

    Abdominal aortic aneurysm (AAA) is a common aortic disease with a progressive nature. There is no approved pharmacological treatment to effectively slow aneurysm growth or prevent rupture. Necroptosis is a form of programmed necrosis that is regulated by receptor-interacting protein kinases (RIPs). We have recently demonstrated that the lack of RIP3 in mice prevented aneurysm formation. The goal of the current study is to test whether perturbing necroptosis affects progression of existing aneurysm using the RIP1 inhibitors Necrostatin-1 (Nec-1) and an optimized form of Nec-1, 7-Cl-O-Nec-1 (Nec-1s). Seven days after aneurysm induction by elastase perfusion, mice were randomly administered DMSO, Nec-1 (3.2 mg/kg/day) and Nec-1s (1.6 mg/kg/day) via intraperitoneal injection. Upon sacrifice on day 14 postaneurysm induction, the aortic expansion in the Nec-1s group (64.12 ± 4.80%) was significantly smaller than that of the DMSO group (172.80 ± 13.68%) (P aortic diameter of Nec-1 treated mice appeared to be smaller (121.60 ± 10.40%) than the DMSO group, though the difference was not statistically significant (P = 0.1). Histologically, the aortic structure of Nec-1s-treated mice appeared normal, with continuous and organized elastin laminae and abundant αActin-expressing SMCs. Moreover, Nect-1s treatment diminished macrophage infiltration and MMP9 accumulation and increased aortic levels of tropoelastin and lysyl oxidase. Together, our data suggest that pharmacological inhibition of necroptosis with Nec-1s stabilizes pre-existing aneurysms by diminishing inflammation and promoting connective tissue repair. PMID:28186202

  7. Analysis of seismic disaster failure mechanism and dam-break simulation of high arch dam

    Science.gov (United States)

    Zhang, Jingkui; Zhang, Liaojun

    2014-06-01

    Based on a Chinese national high arch dam located in a meizoseismal region, a nonlinear numerical analysis model of the damage and failure process of a dam-foundation system is established by employing a 3-D deformable distinct element code (3DEC) and its re-development functions. The proposed analysis model considers the dam-foundation-reservoir coupling effect, influence of nonlinear contact in the opening and closing of the dam seam surface and abutment rock joints during strong earthquakes, and radiation damping of far field energy dissipation according to the actual workability state of an arch dam. A safety assessment method and safety evaluation criteria is developed to better understand the arch dam system disaster process from local damage to ultimate failure. The dynamic characteristics, disaster mechanism, limit bearing capacity and the entire failure process of a high arch dam under a strong earthquake are then analyzed. Further, the seismic safety of the arch dam is evaluated according to the proposed evaluation criteria and safety assessment method. As a result, some useful conclusions are obtained for some aspects of the disaster mechanism and failure process of an arch dam. The analysis method and conclusions may be useful in engineering practice.

  8. Abdominal aortic aneurysm surgery

    DEFF Research Database (Denmark)

    Gefke, K; Schroeder, T V; Thisted, B

    1994-01-01

    The goal of this study was to identify patients who need longer care in the ICU (more than 48 hours) following abdominal aortic aneurysm (AAA) surgery and to evaluate the influence of perioperative complications on short- and long-term survival and quality of life. AAA surgery was performed in 553......, 78% stated that their quality of life had improved or was unchanged after surgery and had resumed working. These data justify a therapeutically aggressive approach, including ICU therapy following AAA surgery, despite failure of one or more organ systems....

  9. Idiopathic pulmonary artery aneurysm.

    Science.gov (United States)

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

    2009-05-01

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

  10. Right circumflex retro-oesophageal aortic arch with coarctation of a high-positioned right arch

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Kyung-Sik; Yong, Hwan Seok; Woo, Ok Hee; Kang, Eun-Young [Korea University Guro Hospital, Department of Radiology, Seoul (Korea); Lee, Joo-Won [Korea University Guro Hospital, Department of Paediatrics, Seoul (Korea)

    2007-06-15

    We present a rare case of right circumflex retro-oesophageal aortic arch with coarctation of a high-positioned right arch. A 7-month-old boy presented with a cardiac murmur. Cardiac situs was normal and there was no evidence of an intracardiac shunt or patent ductus arteriosus. MR aortography revealed a right aortic arch that was high-positioned, tortuous and narrowed. This right aortic arch crossed the midline behind the oesophagus and continued as a left-sided descending aorta. The left common carotid and subclavian arteries arose from a large branching vascular structure that derived from the top of the left-sided descending aorta. The right common carotid artery arose from the ascending aorta. The proximal portion of the right common carotid artery showed very severe stenosis and poststenotic dilatation. The right subclavian artery originated distal to the narrowed and tortuous segment of the aortic arch. (orig.)

  11. Arch Index: An Easier Approach for Arch Height (A Regression Analysis

    Directory of Open Access Journals (Sweden)

    Hironmoy Roy

    2012-04-01

    Full Text Available Background: Arch-height estimation though practiced usually in supine posture; is neither correct nor scientific as referred in literature, which favour for standing x-rays or arch-index as yardstick. In fact the standing x-rays can be excused for being troublesome in busy OPD, but an ink-footprint on simple graph-sheet can be documented, as it is easier, cheaper and requires almost no machineries and expertisation. Objective: So this study aimed to redefine the inter-relationship of the radiological standing arch-heights with the arch-index for correlation and regression so that from the later we can derive the radiographical standing arch-height values indirectly, avoiding the actual maneuver. Methods: The study involved 103 adult subjects attending at a tertiary care hospital of North Bengal. From the standing x-rays of foot, the standing navicular, talar heights were measured, and ‘normalised’ with the foot length. In parallel foot-prints also been obtained for arch-index. Finally variables analysed by SPSS software. Result: The arch-index showed significant negative correlations and simple linear regressions with standing navicular height, standing talar height as well as standing normalised navicular and talar heights analysed in both sexes separately with supporting mathematical equations. Conclusion: To measure the standing arch-height in a busy OPD, it is wise to have the foot-print first. Arch-index once get known, can be put in the equations as derived here, to predict the preferred standing arch-heights in either sex.

  12. Improving the efficiency of abdominal aortic aneurysm wall stress computations.

    Science.gov (United States)

    Zelaya, Jaime E; Goenezen, Sevan; Dargon, Phong T; Azarbal, Amir-Farzin; Rugonyi, Sandra

    2014-01-01

    An abdominal aortic aneurysm is a pathological dilation of the abdominal aorta, which carries a high mortality rate if ruptured. The most commonly used surrogate marker of rupture risk is the maximal transverse diameter of the aneurysm. More recent studies suggest that wall stress from models of patient-specific aneurysm geometries extracted, for instance, from computed tomography images may be a more accurate predictor of rupture risk and an important factor in AAA size progression. However, quantification of wall stress is typically computationally intensive and time-consuming, mainly due to the nonlinear mechanical behavior of the abdominal aortic aneurysm walls. These difficulties have limited the potential of computational models in clinical practice. To facilitate computation of wall stresses, we propose to use a linear approach that ensures equilibrium of wall stresses in the aneurysms. This proposed linear model approach is easy to implement and eliminates the burden of nonlinear computations. To assess the accuracy of our proposed approach to compute wall stresses, results from idealized and patient-specific model simulations were compared to those obtained using conventional approaches and to those of a hypothetical, reference abdominal aortic aneurysm model. For the reference model, wall mechanical properties and the initial unloaded and unstressed configuration were assumed to be known, and the resulting wall stresses were used as reference for comparison. Our proposed linear approach accurately approximates wall stresses for varying model geometries and wall material properties. Our findings suggest that the proposed linear approach could be used as an effective, efficient, easy-to-use clinical tool to estimate patient-specific wall stresses.

  13. Combined use of cellulose acetate polymer and retrievable platinum coils for the thrombosis of cervical carotid aneurysms.

    Directory of Open Access Journals (Sweden)

    Hirotsune N

    2000-08-01

    Full Text Available Cellulose acetate polymer (CAP solution is a new liquid embolic material, and it has been used clinically for the thrombosis of cerebral aneurysms. The purpose of the study was to test a method of aneurysm treatment. In an experimental model, retrievable interlocking detachable coils (IDCs were used to create an intraaneurysmal frame or prop and then CAP was injected into 20 experimentally induced canine cervical aneurysms. Intraaneurysmal thrombosis was induced 1 week after aneurysm creation. Complete thrombosis was attempted in 12 aneurysms, and partial thrombosis was attempted in 4. Four other aneurysms served as controls. Follow-up angiography was performed for up to 8 weeks, and with the exception of 4 aneurysms, which were kept for a 2-year long-term follow-up study, the aneurysms were then harvested for histological examination. Thrombosis was successfully achieved in all cases except for 2 enlarged aneurysms that were initially partially thrombosed. No thromboembolism to distal vessels was observed. No compaction or shift of the CAP-IDC complex occurred even after 2 years. Histologically, CAP and IDCs conformed to the massive thrombotic complex without any fragmentation. By creating a frame or prop with retrievable microcoils, we were able to inject the CAP implies a comparison safely and precisely than has been previously reported. Our findings suggest that this method will be useful for the treatment of cerebral aneurysms.

  14. Physical Theory of Narrow-Band Sounds Associated with Intracranial Aneurysms

    Science.gov (United States)

    Mast, T. Douglas

    Intracranial aneurysms in humans are sometimes associated with narrow-band sound. The sounds of interest have frequencies on the order of 500 Hz. Bandwidths observed correspond to quality factors on the order of 30. The present thesis offers a physical theory of the mechanism of excitation of these sounds. It is shown that an aneurysm can be modeled as a lumped-element resonator in which the kinetic energy is associated with the motion of blood in the neck of the aneurysm and the potential energy is stored in the flexible walls of the aneurysm sac. However, the quality factors of aneurysms as lumped-element resonators are seen to be much smaller than the observed quality factors of aneurysm sounds, so that aneurysm sounds cannot be explained as a simple resonance phenomenon associated with external forcing. It is shown that the best explanation for aneurysm sounds is a self-excited oscillation of the system comprised of the aneurysm and the unstable mean flow; this oscillation is explained quantitatively here for the first time. In the theory developed in this thesis, limit cycles of the aneurysm-flow system are found using describing -function analysis. Results of the theory agree quantitatively with experiments performed on flow-excited Helmholtz resonators and agree qualitatively with the observed characteristics of aneurysm sounds. The bandwidths of observed aneurysm sounds for a time-varying mean flow are predicted and compared with bandwidths of sounds due to periodic vortex shedding in the absence of any resonator. It is shown that the presence of a resonator causes a locking-in of the flow disturbances to the sounding frequency of the resonator, resulting in a narrow observed bandwidth, even for a time -varying mean flow. Bandwidth considerations make it possible to distinguish sounds associated with self-excited oscillations of aneurysms from sounds due to purely fluid-mechanical mechanisms. The theory presented here can be taken as a starting point for

  15. Reference points suitable for evaluation of the additional arch length required for leveling the curve of Spee

    Science.gov (United States)

    Cho, Yong-Hwa; Gang, Sung-Nam

    2016-01-01

    Objective The additional arch length required for leveling (AALL) the curve of Spee (COS) can be estimated by subtracting the two-dimensional (2D) arch circumference, which is the projection of the three-dimensional (3D) arch circumference onto the occlusal plane, from the 3D arch circumference, which represents the arch length after leveling the COS. The purpose of this study was to determine whether the cusp tips or proximal maximum convexities are more appropriate reference points for estimating the AALL. Methods Sixteen model setups of the mandibular arch with COS depths ranging from 0 mm to 4.7 mm were constructed using digital simulation. Arch circumferences in 2D and 3D were measured from the cusp tips and proximal maximum convexities and used to calculate the AALL. The values obtained using the two reference points were compared with the paired t-test. Results Although the 3D arch circumference should be constant regardless of the COS depth, it decreased by 3.8 mm in cusp tip measurements and by 0.4 mm in proximal maximum convexity measurements as the COS deepened to 4.7 mm. AALL values calculated using the cusp tips as reference points were significantly smaller than those calculated using the proximal maximum convexities (p = 0.002). Conclusions The AALL is underestimated when the cusp tips are used as measurement reference points; the AALL can be measured more accurately using the proximal maximum convexities. PMID:27896209

  16. Dental Arch Dimension of Malay Ethnic Group

    Directory of Open Access Journals (Sweden)

    H. A. Mohammad

    2011-01-01

    Full Text Available Problem statement: Many previous studies tried to define and put specific measurements for dental arches dimension in different ethnics groups. However, these studies may be specific to an ethnic group and cannot always be applied to other ethnic types. The aim of this study: is to obtain specific dental arch dimensions for Malaysian Malay ethnic groups and compare between both genders. Approach: Involved clinical examination, collection and analysis of 60 dental cast of Malaysian Malay subjects from pure ethnic group (30 males and 30 females, 20-24 years old. All dental landmarks were located and determined and subsequently measurements had been done according to specific points have been selected. Statistical analysis were done using t-test. Results: Dental arch dimension were established in normal occlusion for Malaysian Malay ethnic group in this study. No significant difference was observed in arch dimensions between male and female of Malaysian Malay. Conclusion: These measurement should be considered during treatment, especially in prosthodontics and orthodontics where arch dimension can be modified appreciably.

  17. Microsurgical management of posterior circulation aneurysms

    Directory of Open Access Journals (Sweden)

    SHI Xiang-en

    2012-02-01

    Full Text Available Objective To retrospectively analyze effective methods for surgical management of posterior circulation aneurysms. Methods There were 42 patients with posterior circulation aneurysms [26 cases of basilar aneurysm (27 aneurysms, 16 cases of vertebral aneurysm (17 aneurysms]. There were 15 patients underwent bypass surgery [4 external carotid artery-P2 segment of posterior cerebral artery (ECA-P2, 2 internal carotid artery-P2 segment of posterior cerebral artery (ICA-P2, 2 internal maxillary artery-P2 segment of posterior cerebral artery (IMA-P2, 2 intracranial segment of vertebral artery-extracranial segment of vertebral artery, 5 occipital artery-posterior inferior cerebellar artery (OA-PICA] and 27 patients underwent simple surgical clipping. Results Activities of daily life of 37 patients recovered to normal (14 patients with aneurysm on the top of basilar artery, 3 with aneurysm on the trunk of basilar artery, 9 with vertebral aneurysm, 5 with posterior inferior cerebellar artery aneurysm, 4 with aneurysm on the junction of P1-P2 segment of posterior cerebral artery, 1 with superior cerebellar artery, and 1 with anterior inferior cerebellar aneurysm. None of them occurred operation-related neurological dysfunction. The recovery rate was 88.09% . Among the other patients, 1 with aneurysm on the top of basilar artery presented severe signs and symptoms of neurological defect and cannot take care of oneself, 2 patients (1 with aneurysm on the top of basilar artery, 1 with aneurysm on the trunk of basilar artery occurred brain stem hemorrhage after operation, and died at perioperative period, 2 with vertebral aneurysm relapsed and was cured after treatment. Conclusion Posterior circulation aneurysm which is not suitable for surgical clipping can be treated with intra? and extra?cranial vessel bypass. It may avoid the risk of surgical clipping of aneurysm.

  18. Effects of Asthma and Inhalation corticosteroids on the dental arch morphology in children

    Directory of Open Access Journals (Sweden)

    S S Kumar

    2012-01-01

    Full Text Available Background: Hereditary, environmental and developmental factors play an important role in dentofacial development, as well as the initiation of malocclusion disorder. Allergic phenomenon such as asthma that induces an alternative mode of breathing in patients is a contributing factor in development of the dental arch. Aim: Our aim in this study was to evaluate the dentoalveolar morphology in asthmatic children and to analyze the effects of asthmatic medications on the dental arch. Setting and Design : This study is centered on 44 asthmatic children aged between 6-12 years from J.S.S Hospital, Mysore. Selected variables from model analysis of the casts of the asthmatic group were subjected to comparison with those of the non-asthmatic group, which comprised of 44 non-asthmatic children. Selected parameters were arch width, arch length and palatal depth. Materials and Methods : Impressions of upper and lower arches were made with rubber based impression material. A sliding digital caliper was used to measure the casts for arch width and arch length. A palatal depth gauge was used to measure the palatal depth. Statistical Analysis : Differences in arch widths, arch lengths and palatal depths between asthmatics and non-asthmatics groups were evaluated by independent sample t-tests. Chi-square test was applied to assess the frequency of occurrence of malocclusion in the asthmatic children. Result: The results obtained revealed that the arch length and palatal depth of asthmatic group had higher values compared to that of non-asthmatic groups for both age groups (6 to 8-year-old males and females, 10 to 12-year-old males and females. Inter molar width showed a significant lower value in asthmatics in the maxillary arches of 10 to 12-year-old females. Fifty percent of the asthmatic children aged 10 to 12-years had open-bite. Children under regular medication showed significant deviation in the dentoalveolar morphology as compared to those under

  19. A Review of Diseases of Aortic Arch: Diagnosis by CTA

    Directory of Open Access Journals (Sweden)

    S. Sabouri

    2007-05-01

    Full Text Available The noninvasive revolution in cardiovascular imaging has altered the diagnostic algorithm for all types of acquired and congenital cardiovascular disease. CT techniques are commonly used in the diagnosis of aortic arch and its major branch vessels as well as thoracic and abdominal aortic diseases. CT angiogra-phy combines with CT scans obtained detailed in-formation on precise morphology and extent of dis-ease. Studies were performed on an MDCT unit (4row GE light speed. In infants and small children, the seda-tion rate for CT was lower than that used for patients of similar age undergoing cardiac MR imaging. Seda-tion times ranged between 5 and 10 min, in the pedi-atric population, MDCT was performed with a 1- to 2.5-mm slice thickness in adults, MDCT was per-formed with a 2.5-mm slice thickness with 50% re-construction overlap, pitch 0.75-1.CT angiographic studies were performed with nonionic contrast mate-rial with iodine concentrations of 300 mg/mL admin-istered at a dose of 2-3 mL/kg. Contrast material was injected by power injection, followed by normal sa-line, an automated bolus-tracking technique was used at an injection rate of 2-4 mL/sec. the bolus-tracking device was placed on the ascending aorta. For pa-tients with thoracic outlet syndrome, CT angiogram was performed with neutral position of arm and ab-duction of the arm. Radiologist studied the CT image data in an axial cine paging mode as well as multiplanar reformations. To plan effective management of Aorta disease, CTA is displayed using a combination of 3D images, such as those obtained by multiplanar reformation (MPR, curved planar reformation (CPR, maximum intensity projection (MIP and volume rendering (VR. Case reports include coarctation of aorta, vascular ring, right sided aorta, interrupted aortic arch, abber-ant vessels, paitent ductus arteriosus, subclavian steel syndrome, aneurysm, dissection, thoracic outlet syn-drome, arthritis and atherosclerotic stenosis.

  20. MATHEMATICAL ANALYSIS OF DENTAL ARCH OF CHILDREN IN NORMAL OCCLUSION: A LITERATURE REVIEW

    Directory of Open Access Journals (Sweden)

    M. Abu-Hussein DDS, MScD, MSc, DPD

    2012-03-01

    Full Text Available AIM. This paper is an attempt to compare and analyze the various mathematical models for defining the dental arch curvature of children in normal occlusion based upon a review of available literature. Background. While various studies have touched upon ways to cure or prevent dental diseases and upon surgical ways for teeth reconstitution to correct teeth anomalies during childhood, a substantial literature also exists, attempting to mathematically define the dental arch of children in normal occlusion. This paper reviews these dental studies and compares them analytically. Method. The paper compares the different mathematical approaches, highlights the basic assumptions behind each model, underscores the relevancy and applicability of the same, and also lists applicable mathematical formulae. Results. Each model has been found applicable to specific research conditions, as a universal mathematical model for describing the human dental arch still eludes satisfactory definition. The models necessarily need to include the features of the dental arch, such as shape, spacing between teeth and symmetry or asymmetry, but they also need substantial improvement. Conclusions. While the paper shows that the existing models are inadequate in properly defining the human dental arch, it also acknowledges that future research based on modern imaging techniques and computeraided simulation could well succeed in deriving an allinclusive definition for the human dental curve till now eluding the experts.

  1. ARCHES: Advancing Research & Capacity in Hydrologic Education and Science

    Science.gov (United States)

    Milewski, A.; Fryar, A. E.; Durham, M. C.; Schroeder, P.; Agouridis, C.; Hanley, C.; Rotz, R. R.

    2013-12-01

    Educating young scientists and building capacity on a global scale is pivotal towards better understanding and managing our water resources. Based on this premise the ARCHES (Advancing Research & Capacity in Hydrologic Education and Science) program has been established. This abstract provides an overview of the program, links to access information, and describes the activities and outcomes of student participants from the Middle East and North Africa. The ARCHES program (http://arches.wrrs.uga.edu) is an integrated hydrologic education approach using online courses, field programs, and various hands-on workshops. The program aims to enable young scientists to effectively perform the high level research that will ultimately improve quality of life, enhance science-based decision making, and facilitate collaboration. Three broad, interlinked sets of activities are incorporated into the ARCHES program: (A1) the development of technical expertise, (A2) the development of professional contacts and skills, and (A3) outreach and long-term sustainability. The development of technical expertise (A1) is implemented through three progressive instructional sections. Section 1: Students were guided through a series of online lectures and exercises (Moodle: http://wrrs.uga.edu/moodle) covering three main topics (Remote Sensing, GIS, and Hydrologic Modeling). Section 2: Students participated in a hands-on workshop hosted at the University of Georgia's Water Resources and Remote Sensing Laboratory (WRRSL). Using ENVI, ArcGIS, and ArcSWAT, students completed a series of lectures and real-world applications (e.g., Development of Hydrologic Models). Section 3: Students participated in field studies (e.g., measurements of infiltration, recharge, streamflow, and water-quality parameters) conducted by U.S. partners and international collaborators in the participating countries. The development of professional contacts and skills (A2) was achieved through the promotion of networking

  2. Fast virtual stenting with deformable meshes: application to intracranial aneurysms.

    Science.gov (United States)

    Larrabide, Ignacio; Radaelli, Alessandro; Frangi, Alejandro

    2008-01-01

    Intracranial stents are medical devices that are becoming increasingly popular in the treatment of intracranial aneurysms. A methodology that predicts the released stent configuration prior to intervention has the potential to support the physician in the selection of the optimal approach for a specific patient. This paper proposes a fast virtual stenting technique based on constrained simplex deformable models that is able to virtually release stents in arbitrarily shaped vessel and aneurysm models. The technique effectively embeds the geometrical properties of the stent (cell design, strut size and shape and angles between struts) and achieves favorable execution times of the order of one minute.

  3. Severe aortic and arterial aneurysms associated with a TGFBR2 mutation

    Science.gov (United States)

    LeMaire, Scott A; Pannu, Hariyadarshi; Tran-Fadulu, Van; Carter, Stacey A; Coselli, Joseph S; Milewicz, Dianna M

    2008-01-01

    Background A 24-year-old man presented with previously diagnosed Marfan’s syndrome. Since the age of 9 years, he had undergone eight cardiovascular procedures to treat rapidly progressive aneurysms, dissection and tortuous vascular disease involving the aortic root and arch, the thoracoabdominal aorta, and brachiocephalic, vertebral, internal thoracic and superior mesenteric arteries. Throughout this extensive series of cardiovascular surgical repairs, he recovered without stroke, paraplegia or renal impairment. Investigations CT scans, arteriogram, genetic mutation screening of transforming growth factor β receptors 1 and 2. Diagnosis Diffuse and rapidly progressing vascular disease in a patient who met the diagnostic criteria for Marfan’s syndrome, but was later rediagnosed with Loeys–Dietz syndrome. Genetic testing also revealed a de novo mutation in transforming growth factor β receptor 2. Management Regular cardiovascular surveillance for aneurysms and dissections, and aggressive surgical treatment of vascular disease. PMID:17330129

  4. AORTIC ANEURYSM: A RARE CAUSE OF ORTNER’S SYNDROME

    Directory of Open Access Journals (Sweden)

    Sukanta

    2014-11-01

    Full Text Available A 60 year old male patient presented with hoarseness of voice lasting for 2 months. First he was examined by the otorhinolaryngologist of our hospital, who noticed absence of movements of the left vocal cord. Chest X-ray showed a large opacity in the left upper zone and the patient was referred to the pulmonologist. His general physical examination was unremarkable not having any stigmata of Marfan's or Ehler Danlos syndrome. On chest auscultation, a systolic flow murmur was audible and there was decreased breath sound in the left infraclavicular area. Bronchoscopy revealed absence of movement of left vocal cord. His trans-thoracic echocardiography revealed degenerative aortic and mitral valve disease with mild aortic regurgitation and mild mitral regurgitation with dilated aortic aneurysm. A contrast enhanced CT scan of thorax and CT Angio Aortogram revealed fusiform aneurysmal dilatation of the arch of aorta with diameter of 6.2 cm over a length of 12.3 cm showing intraluminal partial thrombus with wall calcification. The patient was advised to undergo surgery. However, after detailed discussion with him and his family, they decided for medical management in view of his advanced age

  5. Surgical Management of Ascending Aortic Aneurysm and Its Complications

    Directory of Open Access Journals (Sweden)

    Sisira Sran

    2014-01-01

    Full Text Available Ascending aortic aneurysms involving the proximal aortic arch, arising anywhere from the aortic valve to the innominate artery, represent various problems in which open surgery is generally required. Surgical options include excision of the aortic pathology or wrapping the aneurysm shell with an aortic Dacron graft. Intervention using the latter method can lead to extravasation of blood along the suture lines resulting in continuous bleeding within the periprosthetic space. The Cabrol technique was developed as a method for decompression of postoperative leaks by the formation of a conduit system from the periprosthetic space to the right atrium. The coronary ostia are anastomosed to a second graft in an end-to-end fashion, which is then anastomosed to the ascending aortic conduit side to side. The native aorta is then sewn around the prosthesis, hereby creating a shunt to drain anastomotic leakage. This shunt reduces postsurgical risk of pseudoaneurysm formation and normally closes a few days following surgery. We discuss the case of a patient who underwent Cabrol’s variation and six months later was demonstrated to have a patent shunt.

  6. Clinical presentation of cerebral aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Cianfoni, Alessandro [Neurocentro della Svizzera Italiana, Ospedale Civico di Lugano, via Tesserete, 46, 6900 Lugano (Switzerland); Pravatà, Emanuele, E-mail: emanuele.pravata@gmail.com [Neurocentro della Svizzera Italiana, Ospedale Civico di Lugano, via Tesserete, 46, 6900 Lugano (Switzerland); De Blasi, Roberto [Neurocentro della Svizzera Italiana, Ospedale Civico di Lugano, via Tesserete, 46, 6900 Lugano (Switzerland); Tschuor, Costa Silvia [Dipartimento di Radiologia, Ospedale Civico di Lugano, via Tesserete, 46, 6900 Lugano (Switzerland); Bonaldi, Giuseppe [U.O. Neuroradiologia, Ospedali Riuniti di Bergamo, Largo Barozzi, 1, 24128 Bergamo (Italy)

    2013-10-01

    Presentation of a cerebral aneurysm can be incidental, discovered at imaging obtained for unrelated causes, can occur in the occasion of imaging obtained for symptoms possibly or likely related to the presence of an unruptured aneurysm, or can occur with signs and symptoms at the time of aneurismal rupture. Most unruptured intracranial aneurysms are thought to be asymptomatic, or present with vague or non-specific symptoms like headache or dizziness. Isolated oculomotor nerve palsies, however, may typically indicate the presence of a posterior circulation aneurysm. Ruptured intracranial aneurysms are by far the most common cause of non-traumatic subarachnoid hemorrhage and represent a neurological emergency with potentially devastating consequences. Subarachnoid hemorrhage may be easily suspected in the presence of sudden and severe headache, vomiting, meningism signs, and/or altered mental status. However, failure to recognize milder and more ambiguous clinical pictures may result in a delayed or missed diagnosis. In this paper we will describe the clinical spectrum of unruptured and ruptured intracranial aneurysms by discussing both typical and uncommon clinical features emerging from the literature review. We will additionally provide the reader with descriptions of the underlying pathophysiologic mechanisms, and main diagnostic pitfalls.

  7. The unruptured intracranial aneurysm treatment score : A multidis ciplinary consensus

    NARCIS (Netherlands)

    Etminan, Nima; Brown, Robert D.; Beseoglu, Kerim; Juvela, Seppo; Raymond, Jean; Morita, Akio; Torner, James C.; Derdeyn, Colin P.; Raabe, Andreas; Mocco, J.; Korja, Miikka; Abdulazim, Amr; Amin-Hanjani, Sepideh; Salman, Rustam Al Shahi; Barrow, Daniel L.; Bederson, Joshua; Bonafe, Alain; Dumont, Aaron S.; Fiorella, David J.; Gruber, Andreas; Hankey, Graeme J.; Hasan, David M.; Hoh, Brian L.; Jabbour, Pascal; Kasuya, Hidetoshi; Kelly, Michael E.; Kirkpatrick, Peter J.; Knuckey, Neville; Koivisto, Timo; Krings, Timo; Lawton, Michael T.; Marotta, Thomas R.; Mayer, Stephan A.; Mee, Edward; Pereira, Vitor Mendes; Molyneux, Andrew; Morgan, Michael K.; Mori, Kentaro; Murayama, Yuichi; Nagahiro, Shinji; Nakayama, Naoki; Niemelä, Mika; Ogilvy, Christopher S.; Pierot, Laurent; Rabinstein, Alejandro A.; Roos, Yvo B W E M; Rinne, Jaakko; Rosenwasser, Robert H.; Ronkainen, Antti; Schaller, Karl; Seifert, Volker; Solomon, Robert A.; Spears, Julian; Steiger, Hans Jakob; Vergouwen, Mervyn D I; Wanke, Isabel; Wermer, Marieke J H; Wong, George K C; Wong, John H.; Zipfel, Gregory J.; Sander Connolly, E.; Steinmetz, Helmuth; Lanzino, Giuseppe; Pasqualin, Alberto; Rüfenacht, Daniel; Vajkoczy, Peter; McDougall, Cameron; Hänggi, Daniel; Leroux, Peter; Rinkel, Gabriel J E; Loch Macdonald, R.

    2015-01-01

    Objective: We endeavored to develop an unruptured intracranial aneurysm (UIA) treatment score (UIATS) model that includes and quantifies key factors involved in clinical decision-making in the management of UIAs and to assess agreement for this model among specialists in UIA management and research.

  8. [False aneurysm of the left ventricle and coronary aneurysms in Behçet disease].

    Science.gov (United States)

    Rolland, J M; Bical, O; Laradi, A; Robinault, J; Benzidia, R; Vanetti, A; Herreman, G

    1993-09-01

    A false left ventricular aneurysm and coronary artery aneurysm were discovered in a 29 year old patient with Behçet's syndrome. The operation under cardiopulmonary bypass consisted of closing the neck of the false aneurysm by an endo-aneurysmal approach with a Gore-Tex patch. The coronary artery aneurysms were respected. There were no postoperative complications. Cardiac involvement is rare in Behçet's syndrome (6%). The originality of this case is the association of two aneurysmal pathologies: the coronary and ventricular aneurysms due to the angiitis and the myocardial fragility induced by ischaemia.

  9. Risk factors for intracranial aneurysm in a Chinese ethnic population

    Institute of Scientific and Technical Information of China (English)

    GU Yu-xiang; CHEN Xian-cheng; SONG Dong-lei; LENG Bing; ZHAO Fan

    2006-01-01

    Background Intracranial aneurysm (IAN) is a protruding bubble or a sac on a brain artery that balloons out over time, which may lead to spontaneous subarachnoid hemorrhage (SAH), ultimately disability and mortality.Current research indicates that the disease is due to multiple causes, including environmental factors and various congenital abnormalities of blood vessels. Apart from congenital predisposition, various high-risk factors such as sex, age, hypertension, and atherosclerosis are involved in the formation of intracranial aneurysms. The aim of this study was to investigate the risk factors associated with the formation of sporadic intracranial aneurysms in Chinese Han ethnic patients.Methods A total of 251 patients with intracranial aneurysm and 338 patients with other cerebral diseases (control group) were enrolled in this study. Single factor and logistic regression model were used to analyze the association of intracranial aneurysms with age; sex; cigarette smoking; alcohol or cocaine consumption; history of hypertension, coronary artery disease, diabetes mellitus and inherited connective tissue disease; and the levels of fasting blood glucose and blood fat. The data expressed as mean ± standard deviation were processed with the statistical software SPSS13. Quantitative and qualitative data were analyzed by the independent-sample t test,and the chi-square test respectively. Logistic regression method was used to analyze the multiple factors.Results In the 251 patients, 163 (64.94%) were at age of 40 to 60 years. Sex (OR, 1.41; 95% CI, 1.01-1.96), cigarette smoking (OR, 1.81; 95% CI, 1.06-3.10), hypertension (OR, 2.32; 95% CI, 1.30-4.16) and fasting blood glucose were significantly associated with intracranial aneurysm (P<0.05). Intracranial aneurysm was correlated with alcohol consumption, coronary artery disease, and the level of blood lipids (P>0.05). Using logistic regression analysis, we identified female sex and advanced age as significant risk

  10. Study on Optimal Grouting Timing for Controlling Uplift Deformation of a Super High Arch Dam

    Science.gov (United States)

    Lin, Peng; Zhu, Xiaoxu; Li, Qingbin; Liu, Hongyuan; Yu, Yongjun

    2016-01-01

    A grouting model is developed for use during the grouting of the complex foundation of a super high arch dam. The purpose as to determine the optimal grouting timing and appropriate grouting pressure involved in controlling the uplift deformation of the dam. The model determines the optimal grouting time as the height of the arch dam increases with the concrete pouring, by checking the tensile stresses in the dam against standard specifications. The appropriate grouting pressures are given on the basis of the actual grouting pressures monitored during the upstream riverbed foundation grouting. An engineering procedure, applying the model, was then proposed and used during foundation grouting under the toe block of the Xiluodu super high-arch dam in south-western China. The quality of the foundation grouting was evaluated against the results from pressurized water permeability tests, acoustic wave velocity tests, elastic modulus tests and panoramic photographing of the rockmass on completion of the foundation grouting. The results indicated that the proposed grouting model can be applied to effectively reduce the uplift deformation and associated cracking risk for super high arch dams, and it can be concluded that the proposed engineering grouting procedure is a valuable tool for improving foundation grouting under the toe blocks of a super high arch dam.

  11. Intracranial aneurysm associated with relapsing polychondritis

    Energy Technology Data Exchange (ETDEWEB)

    Coumbaras, M.; Boulin, A.; Pierot, L. [Dept. of Neuroradiology, Hopital Foch, Suresnes (France); Piette, A.M.; Bletry, O. [Dept. of Medicine, Hopital Foch, Suresnes (France); Graveleau, P. [Dept. of Neurology, Hopital Foch, Suresnes (France)

    2001-07-01

    We describe a 50-year-old man with relapsing polychondritis (RP) involving auricular cartilage, uveitis and hearing loss, who had an aneurysm of the anterior cerebral artery. Intracranial aneurysm is a rare manifestation of RP. (orig.)

  12. A histopathologic study of retinal arterial aneurysms.

    Science.gov (United States)

    Fichte, C; Streeten, B W; Friedman, A H

    1978-04-01

    An isolated retinal arterial aneurysm was found postmortem in the eye of a 75-year-old hypertensive woman, and multiple aneurysms were in the enucleated eye of a 68-year-old hypertensive man with neovascular glaucoma. The aneurysmal sites showed thickening of the vessel walls with hyaline, fibrin, and foamy macrophages. Fresh or organized thrombus partially filled the aneurysmal lumina. Trypsin digestion preparations in Case 2 showed a progressive severity of aneurysmal changes from the simplest "cuff" type to the hemorrhagic "b;pwout" aneurysms with a linear split in the vessel wall. Atheroma was present in the larger arterial branches and fat was in most of the aneurysmal walls. These findings suggested that damage to the arterial wall by cholesterol or other emboli, or by occlusive disease, may predispose especially hypertensive patients to arterial aneurysm formation.

  13. Abdominal aortic aneurysm repair - open - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000240.htm Abdominal aortic aneurysm repair - open - discharge To use the sharing features ... References Orandi BJ, Black JH. Open repair of abdominal aortic aneurysms. In: Cameron JL, Cameron AM, eds. Current Surgical ...

  14. Evaluation of intracranial aneurysms with CT angiography: current status and future direction

    Science.gov (United States)

    Sato, Yutaka; Sickels, William; Quets, Jerome; Crosby, Daniel; Chang, Shereen; Cook-Granroth, Janice; Hoffman, Eric A.

    1997-05-01

    Purpose: To develop a valid, reliable and accurate system of measurement of intracranial aneurysm geometry using volumetric data obtained by CT angiography. Materials and methods: A simple model of lateral saccular aneurysm was created. Three models were prepared with different size of aneurysm sac and neck. Volumetric data was acquired using a Toshiba Xpress SX helical scanner. Geometry of an aneurysm model obtained by workstation linked to the scanner applying volume rendering display and dedicated UNIX based computer applying MPR based method. These results were compared with actual caliper measurements of the model. A clinical case of lateral aneurysm arising from the supraclinoid internal carotid artery was also studied. Results: Both the volume rendered image based method and MPR based method provided accurate geometric information of an aneurysm sac and its neck. Conclusions: Volume rendering technique requires editing by a well-informed operator and subjective, while the MPR based method is more objective and better suited for quantitative analysis. Using these mutually complimentary tools, critical geometric information of an aneurysm can be extracted from volumetric data provided by CTA.

  15. Abdominal aortic aneurysms

    DEFF Research Database (Denmark)

    Lindholt, Jes Sanddal

    2010-01-01

    Although the number of elective operations for abdominal aortic aneurysms (AAA) is increasing, the sex- and age-standardised mortality rate of AAAs continues to rise, especially among men aged 65 years or more. The lethality of ruptured AAA continues to be 80-95%, compared with 5-7% by elective....... The acceptance rate was 77%, and 95% accept control scans. Furthermore, persons at the highest risk of having an AAA attend screening more frequently. We found that 97% of the interval cases developed from aortas that initially measured 2.5-2.9 cm - i.e. approx. only 5% attenders need re-screening at 5-year...... methods for measuring the degree of wall calcification must be developed and validated....

  16. Marfan Syndrome and Related Heritable Thoracic Aortic Aneurysms and Dissections.

    Science.gov (United States)

    De Backer, Julie; Renard, Marjolijn; Campens, Laurence; Mosquera, Laura Muino; De Paepe, Anne; Coucke, Paul; Callewaert, Bert; Kodolitsch, Yskert von

    2015-01-01

    In this overview we aim to address a number of recent insights and developments regarding clinical aspects, etiology, and treatment of Heritable Thoracic Aortic Disease (H-TAD). We will focus on monogenetic disorders related to aortic aneurysms. H-TADs are rare but they provide a unique basis for the study of underlying pathogenetic pathways in the complex disease process of aneurysm formation. The understanding of pathomechanisms may help us to identify medical treatment targets to improve prognosis. Among the monogenetic aneurysm disorders, Marfan syndrome is considered as a paradigm entity and many insights are derived from the study of clinical, genetic and animal models for Marfan syndrome. We will therefore first provide a detailed overview of the various aspects of Marfan syndrome after which we will give an overview of related H-TAD entities.

  17. Surveillance intervals for small abdominal aortic aneurysms

    DEFF Research Database (Denmark)

    Bown, Matthew J; Sweeting, Michael J; Brown, Louise C

    2013-01-01

    Small abdominal aortic aneurysms (AAAs [3.0 cm-5.4 cm in diameter]) are monitored by ultrasound surveillance. The intervals between surveillance scans should be chosen to detect an expanding aneurysm prior to rupture.......Small abdominal aortic aneurysms (AAAs [3.0 cm-5.4 cm in diameter]) are monitored by ultrasound surveillance. The intervals between surveillance scans should be chosen to detect an expanding aneurysm prior to rupture....

  18. Precast Pearl-Chain concrete arch bridges

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

    2015-01-01

    A Pearl-Chain Bridge is a closed-spandrel arch bridge consisting of a number of straight pre-fabricated so called Super-Light Deck elements put together in an arch shape by post-tensioning cables. Several Pearl-Chain arches can be positioned adjacent to each other by a crane to achieve a bridge...... the technology was used. We also study other important components and details in the Pearl-Chain Bridge concept and review the effects of different types of loads. A theoretical case study of a circular 30 m span Pearl-Chain Bridge is presented showing the influence of a number of parameters: The number of post-tensioning......, and gives a large positive bending moment below the load and a smaller negative bending moment in the unloaded side. When the Pearl-Chain Bridge concept is compared to other pre-fabricated arch bridge solutions we find a number of advantages when using Pearl-Chain Bridges: Straight elements, combination...

  19. The use of a new hybrid stentgraft for the repair of extensive thoracic aortic aneurysms with the frozen elephant trunk method - first Polish experiences.

    Science.gov (United States)

    Zembala, Michał; Krasoń, Marcin; Hrapkowicz, Tomasz; Przybylski, Roman; Filipiak, Krzysztof; Borowicz, Marcin; Niklewski, Tomasz; Głowacki, Jan; Wolny, Tomasz; Nadziakiewicz, Paweł; Walas, Ryszard; Zembala, Marian

    2014-09-01

    The frozen elephant trunk (FET) technique is a modification of the traditional elephant trunk method, which was introduced by Borst in 1983 in order to treat extensive thoracic aortic aneurysms. The crux of the new method is the different type of aortic prosthesis, consisting of a Dacron part (with or without branches leading to the arterial vessels which exit the aortic arch) and a port for extracorporeal circulation with a self-expanding nitinol stentgraft. This combination enables a complete one-stage treatment of the pathologies within the arch and the proximal segment of the descending aorta; moreover, it facilitates the performance of a two-stage hybrid treatment of extensive thoracic aortic aneurysms involving a significant part of the descending aorta. This article presents the cases of four patients with extensive aortic disease, who were implanted with Thoraflex prostheses (Vascutek, Scotland).

  20. The use of a new hybrid stentgraft for the repair of extensive thoracic aortic aneurysms with the frozen elephant trunk method – first Polish experiences

    Science.gov (United States)

    Krasoń, Marcin; Hrapkowicz, Tomasz; Przybylski, Roman; Filipiak, Krzysztof; Borowicz, Marcin; Niklewski, Tomasz; Głowacki, Jan; Wolny, Tomasz; Nadziakiewicz, Paweł; Walas, Ryszard; Zembala, Marian

    2014-01-01

    The frozen elephant trunk (FET) technique is a modification of the traditional elephant trunk method, which was introduced by Borst in 1983 in order to treat extensive thoracic aortic aneurysms. The crux of the new method is the different type of aortic prosthesis, consisting of a Dacron part (with or without branches leading to the arterial vessels which exit the aortic arch) and a port for extracorporeal circulation with a self-expanding nitinol stentgraft. This combination enables a complete one-stage treatment of the pathologies within the arch and the proximal segment of the descending aorta; moreover, it facilitates the performance of a two-stage hybrid treatment of extensive thoracic aortic aneurysms involving a significant part of the descending aorta. This article presents the cases of four patients with extensive aortic disease, who were implanted with Thoraflex prostheses (Vascutek, Scotland). PMID:26335241

  1. Study on hemodynamics in patient-specific thoracic aortic aneurysm

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The objective of this study is to investigate the hemodynamics in patient-specific thoracic aortic aneurysm and discuss the reason for formation of aortic plaque.A 3-Dimensional pulsatile blood flow in thoracic aorta with a fusiform aneurysm and 3 main branched vessels was studied numerically with the average Reynolds number of 1399 and the Womersley number of 19.2.Based on the clinical 2-Dimensional CT slice data,the patient-specific geometry model was constructed using medical image process software.Un...

  2. Complex pathologies of angiotensin Ⅱ-induced abdominal aortic aneurysms

    Institute of Scientific and Technical Information of China (English)

    Alan DAUGHERTY; Lisa A. CASSIS; Hong LU

    2011-01-01

    Angiotensin Ⅱ (Angll) is the primary bioactive peptide of the renin angiotensin system that plays a critical role in many cardiovascular diseases.Subcutaneous infusion of Angll into mice induces the development of abdominal aortic aneurysms (AAAs).Like human AAAs,Angll-induced AAA tissues exhibit progressive changes and considerable heterogeneity.This complex pathology provides an impediment to the quantification of aneurysmal tissue composition by biochemical and immunostaining techniques.Therefore,while the mouse model of Angll-induced AAAs provides a salutary approach to studying the mechanisms of the evolution of AAAs in humans,meaningful interpretation of mechanisms requires consideration of the heterogeneous nature of the diseased tissue.

  3. Assembly and lifting of Pearl-Chain arches

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Viebæk, N.E.

    2015-01-01

    Pearl-Chain arches were invented at the Technical University of Denmark in cooporation with the company Abeo A/S. The system uses specially designed, pre-fabricated concrete elements that are post-tensioned together into an arch shape, which is then lifted into place. The arches can be used both...

  4. Comparative study of novel endovascular treatment techniques for intracranial aneurysms

    Science.gov (United States)

    Cantón, Gádor; Lasheras, Juan C.; Levy, David I.; Sparks, Steven R.

    2002-11-01

    Intracranial aneurysms are life-threatening vascular lesions, which are potentially treatable to avoid the consequences of their rupture. Current treatments, either surgical or endovascular, are all guided to reduce the hemodynamic forces acting on the aneurysm wall in an effort to minimize the risk of rupture. Surgical clipping is still the most used technique to treat this type of aneurysm but there is a continued demand for less invasive approaches. This has led to the development of several endovascular techniques. We report here a comparative study of the reduction in the hemodynamic stresses and the modification of the flow in the parent vessel resulting from the use of three different techniques. The first one consists of endosaccular packing with platinum coils (GDC, Target Therapeutics), which is already widely used but its long-term efficacy has not yet been determined. The second one consists of the embolization of the aneurismal sac with Onyx, a polymer which hardens when in contact with the blood (being developed by Micro Therapeutics, Inc.). The third one involves the packing of the sac with hydrocoils, platinum wires coated with a gel which quickly hydrates when in contact with blood (developed by MicroVention). A Digital Particle Image Velocimetry (DPIV) system is used to measure in vitro the velocity field inside a model of an ACOM aneurysm (an aneurysm forming in the anterior communicating artery). Physiological accurate pulsatile flow conditions are input to the arterial model through a programmable pump. The measurements show that although all treatment techniques lead to a reduction in both normal and tangential shear stresses on the aneurismal sac, each one of them also leads to different modifications of the flow in the parent vessel which may have consequences related to potential for clotting. Comparison of the untreated aneurysm with the above three treated cases also showed that the characteristics of the wall shear stresses on the parent

  5. Phase contrast MRI in intracranial aneurysms

    NARCIS (Netherlands)

    van Ooij, P.

    2012-01-01

    Intracranial aneurysms are outpouchings of intracranial arteries that cause brain hemorrhage after rupture. Unruptured aneurysms can be treated but the risk of treatment may outweigh the risk of rupture. Local intra-aneurysmal hemodynamics can contribute substantially to the rupture risk estimation

  6. [Albert Einstein and his abdominal aortic aneurysm].

    Science.gov (United States)

    Cervantes Castro, Jorge

    2011-01-01

    The interesting case of Albert Einstein's abdominal aortic aneurysm is presented. He was operated on at age 69 and, finding that the large aneurysm could not be removed, the surgeon elected to wrap it with cellophane to prevent its growth. However, seven years later the aneurysm ruptured and caused the death of the famous scientist.

  7. Paraclinoid aneurysm concealed by sphenoid wing meningioma.

    Science.gov (United States)

    Petrecca, Kevin; Sirhan, Denis

    2009-02-01

    The coexistence of brain tumours and aneurysms is rare. In all previously reported cases the aneurysm was detectable by angiography. We report here a case in which a paraclinoid internal carotid artery aneurysm was coexistent and concealed from angiographic detection by an adjacent parasellar meningioma.

  8. Research of air-cushion isolation effects on high arch dam reservoir

    Science.gov (United States)

    Zhang, Shao-Jie; Chen, Jiang; Zhang, Yuan-Ze; Liu, Hao-Wu

    2011-10-01

    A three-dimensional (3D) finite element model of air-cushion isolated arch dam is presented with the nonlinear gas-liquid-solid multi-field dynamic coupling effect taken into account. In this model, the displacement formulation in Lagrange method, pressure formulation in Euler method, nonlinear contact model based on Coulomb friction law are applied to the air-cushion, reservoir and contraction joint domain, respectively. The dynamic response of Jinping I arch dam with a height of 305 m is analyzed using the seismic records of the Wenchuan Earthquake in 2008. Numerical results show that the air-cushion isolation reduces significantly the hydrodynamic pressure as well as the opening width for the contraction joints of high arch dam.

  9. Damage propagation in a masonry arch subjected to slow cyclic and dynamic loadings

    Directory of Open Access Journals (Sweden)

    J. Toti

    2014-07-01

    Full Text Available In the present work, the damage propagation of a masonry arch induced by slow cyclic and dynamic loadings is studied. A two-dimensional model of the arch is proposed. A nonlocal damage-plastic constitutive law is adopted to reproduce the hysteretic characteristics of the masonry material, subjected to cyclic static loadings or to harmonic dynamic excitations. In particular, the adopted cohesive model is able to take into account different softening laws in tension and in compression, plastic strains, stiffness recovery and loss due to crack closure and reopening. The latter effect is an unavoidable feature for realistically reproducing hysteretic cycles. In the studied case, an inverse procedure is used to calibrate the model parameters. Then, nonlinear static and dynamic responses of the masonry arch are described together with damage propagation paths.

  10. Basic fibroblast growth factor gene transfection in repair of internal carotid artery aneurysm wall

    Institute of Scientific and Technical Information of China (English)

    Lei Jiao; Ming Jiang; Jinghai Fang; Yinsheng Deng; Zejun Chen; Min Wu

    2012-01-01

    Surgery or interventional therapy has some risks in the treatment of cerebral aneurysm. We established an internal carotid artery aneurysm model by dripping elastase in the crotch of the right internal and external carotid arteries of New Zealand rabbits. Following model induction, lentivirus carrying basic fibroblast growth factor was injected through the ear vein. We found that the longer the action time of the lentivirus, the smaller the aneurysm volume. Moreover, platelet-derived growth factor expression in the aneurysm increased, but smooth muscle 22 alpha and hypertension-related gene 1 mRNA expression decreased. At 1, 2, 3, and 4 weeks following model establishment, following 1 week of injection of lentivirus carrying basic fibroblast growth factor, the later the intervention time, the more severe the blood vessel damage, and the bigger the aneurysm volume, the lower the smooth muscle 22 alpha and hypertension-related gene 1 mRNA expression. Simultaneously, platelet-derived growth factor expression decreased. These data suggest that recombinant lentivirus carrying basic fibroblast growth factor can repair damaged cells in the aneurysmal wall and inhibit aneurysm dynamic growth, and that the effect is dependent on therapeutic duration.

  11. archAR: an archaeological augmented reality experience

    Science.gov (United States)

    Wiley, Bridgette; Schulze, Jürgen P.

    2015-03-01

    We present an application for Android phones or tablets called "archAR" that uses augmented reality as an alternative, portable way of viewing archaeological information from UCSD's Levantine Archaeology Laboratory. archAR provides a unique experience of flying through an archaeological dig site in the Levantine area and exploring the artifacts uncovered there. Using a Google Nexus tablet and Qualcomm's Vuforia API, we use an image target as a map and overlay a three-dimensional model of the dig site onto it, augmenting reality such that we are able to interact with the plotted artifacts. The user can physically move the Android device around the image target and see the dig site model from any perspective. The user can also move the device closer to the model in order to "zoom" into the view of a particular section of the model and its associated artifacts. This is especially useful, as the dig site model and the collection of artifacts are very detailed. The artifacts are plotted as points, colored by type. The user can touch the virtual points to trigger a popup information window that contains details of the artifact, such as photographs, material descriptions, and more.

  12. The use of a new hybrid stentgraft for the repair of extensive thoracic aortic aneurysms with the frozen elephant trunk method – first Polish experiences

    OpenAIRE

    Zembala, Michał; Krasoń, Marcin; Hrapkowicz, Tomasz; Przybylski, Roman; Filipiak, Krzysztof; Borowicz, Marcin; Niklewski, Tomasz; Głowacki, Jan; Wolny, Tomasz; Nadziakiewicz, Paweł; Walas, Ryszard; Zembala, Marian

    2014-01-01

    The frozen elephant trunk (FET) technique is a modification of the traditional elephant trunk method, which was introduced by Borst in 1983 in order to treat extensive thoracic aortic aneurysms. The crux of the new method is the different type of aortic prosthesis, consisting of a Dacron part (with or without branches leading to the arterial vessels which exit the aortic arch) and a port for extracorporeal circulation with a self-expanding nitinol stentgraft. This combination enables a comple...

  13. Research on Three-dimensional Finite Element Modeling of Human Foot and Effect of Arch Support Insert Height on Foot Comfort%足三维有限元建模及鞋垫腰窝高度对足舒适性的影响研究

    Institute of Scientific and Technical Information of China (English)

    林田; 王伟

    2015-01-01

    探讨建立足部三维有限元模型的方法,并建立一系列腰窝高度的鞋垫模型,应用模型模拟分析得出足底压力分布及骨骼受力情况,找出穿着最舒适时的腰窝高度。基于CT数据,建立包括骨骼,软骨,软组织,韧带和足底腱膜,考虑材料非线性的足部模型。截取腰窝曲面,建立5个腰窝高度的鞋垫模型。利用完整的有限元模型对行走中立期进行了静态模拟。有限元分析结果表明,满腰窝高度的鞋垫会对第二跖骨造成压迫,降低舒适感;综合舒适度函数可得出1/2-3/4腰窝高度的鞋垫具有最佳的舒适性,与实验得出的结论相同。提出从足舒适度角度设计鞋垫的腰窝高度时应综合考虑足底压力分布和跖骨应力,为设计鞋垫和研究足部各种临床状况提供了参考。%To investigate the best arch support insert height, a three-dimensional ( 3D) parametric comprehensive finite element ( FE) model of foot is established and the relationship between the plantar pressure and foot bone stress and the arch support insert is studied. Based on 3D CT scanned data of the right foot of a healthy volunteer, an accurate foot geometric model, including bones, cartilages, soft tissue, ligaments and plantar fascia, and 5 arch support inserts geometric models of different height overlald with the curved arch surface are established. The overal foot-insert FE model is established by combining the foot and arch support insert model, and the static finite element analysis of gait mid-stance phase is performed by considering the material nonlinearity. The para-metric FE analysis results show that the 2nd metatarsal is squeezed and the foot comfort is decreased with ful arch support insert, and the most favorable insert height is between 1/2-3/4 arch height from the plantar pressure effect and metatarsal stress effect, which is the same to the experimental result. Both the plantar pressure

  14. Subarachnoid hemorrhage after aneurysm surgery

    Directory of Open Access Journals (Sweden)

    Carlos Gilberto Carlotti Junior

    1996-06-01

    Full Text Available The surgical treatment of intracranial aneurysms by clipping is recognized as effective and definitive. However some cases that suffered a new subarachnoid hemorrhage (SAH some time after they were submitted to aneurysm clipping have raised doubts about the concept of "cure"after this treatment. Eleven patients previously submitted to aneurysm clipping who presented a new SAH were analyzed. The time elapsed from surgery to SAH varied from 3 to 10 years. After SAH four patients had a poor outcome. The new episode of SAH occurred due to intrinsic factors of the cerebral vasculature: 1. a weak point of the vessel wall near the previous aneurysm, 2. a weak point of another vessel far from the previous aneurysm, 3. a previous infundibular dilation of the posterior communicating artery; and due to technical problems: 1. aneurysm not identified during the previous treatment, 2. aneurysm deliberately left untreated, 3. persistence of the aneurysm due to inappropriate surgery, 4. persistency of part of the aneurysm neck after clipping and 5. slipping of the clip from the neck of the aneurysm. The measures to prevent new SAH after surgery start with adequate preoperative angiographic studies, a careful inspection of the position of the clip and emptying of the aneurysm. Early angiography studies may reveal a persistent neck and later ones may reveal newly developed aneurysms. In conclusion, SAH after aneurysm clipping is a late and severe phenomenon and the concept of "cure" after this surgery should be interpreted with caution.O tratamento cirúrgico dos aneurismas cerebrais através de sua clipagem é reconhecido como eficaz e definitivo. Entretanto alguns casos sofrem nova hemorragia algum tempo após a cirurgia, deixando dúvidas sobre a "cura" pelo tratamento. Onze pacientes submetidos anteriormente a clipagem do aneurisma e que apresentaram nova hemorragia foram analisados. O intervalo de tempo da cirurgia para a nova hemorragia foi de 3 a 10 anos

  15. Earthquake safety assessment of concrete arch and gravity dams

    Institute of Scientific and Technical Information of China (English)

    Lin Gao; Hu Zhiqiang

    2005-01-01

    Based on research studies currently being carried out at Dalian University of Technology, some important aspects for the earthquake safety assessment of concrete dams are reviewed and discussed. First, the rate-dependent behavior of concrete subjected to earthquake loading is examined, emphasizing the properties of concrete under cyclic and biaxial loading conditions. Second, a modified four-parameter Hsieh-Ting-Chen viscoplastic consistency model is developed to simulate the rate-dependent behavior of concrete. The earthquake response of a 278m high arch dam is analyzed, and the results show that the strain-rate effects become noticeable in the inelastic range. Third, a more accurate non-smooth Newton algorithm for the solution of three-dimensional frictional contact problems is developed to study the joint opening effects of arch dams during strong earthquakes. Such effects on two nearly 300m high arch dams have been studied. It was found that the canyon shape has great influence on the magnitude and distribution of the joint opening along the dam axis. Fourth, the scaled boundary finite element method presented by Song and Wolf is employed to study the dam-reservoir-foundation interaction effects of concrete dams. Particular emphases were placed on the variation of foundation stiffness and the anisotropic behavior of the foundation material on the dynamic response of concrete dams. Finally, nonlinear modeling of concrete to study the damage evolution of concrete dams during strong earthquakes is discussed. An elastic-damage mechanics approach for damage prediction of concrete gravity dams is described as an example. These findings are helpful in understanding the dynamic behavior of concrete dams and promoting the improvement of seismic safety assessment methods.

  16. A failure of matrix metalloproteinase inhibition in the prevention of rat intracranial aneurysm formation

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, T.J.; Kallmes, D.F. [Mayo Clinic and Foundation, Department of Radiology, Rochester, MN (United States); Marx, W.F. [Asheville Radiology Associates, Asheville, NC (United States)

    2006-03-15

    We tested the hypothesis that nonspecific matrix metalloproteinase (MMP) inhibition with doxycycline would decrease the incidence of intracranial aneurysm formation in a rat aneurysm model. We performed common carotid artery ligation on 96 Long-Evans rats. A treatment group of 48 animals was chosen at random to receive oral doxycycline (3 mg/kg) in addition to standard rat chow, and the control group of 48 animals received standard rat chow only. The major circle of Willis arteries was dissected at 1 year following carotid ligation, and the proportions of animals with aneurysms were compared between groups using Fisher's exact test. Four animals given oral doxycycline and ten control animals expired before 1 year. Of the examined animals, eight saccular intracranial aneurysms were found in 8 of 45 animals which had received doxycycline (17.8%) and seven saccular intracranial aneurysms were found in 7 of 37 control animals (18.9%). There was no significant difference in aneurysm formation between the doxycycline-treated and control groups (P=0.894). Nonspecific MMP inhibition with doxycycline is not effective in preventing intracranial aneurysm formation in a rat model. (orig.)

  17. Transluminal Attenuation Gradient for Thrombotic Risk Assessment in Kawasaki Disease Patients with Coronary Artery Aneurysms

    Science.gov (United States)

    Grande Gutierrez, Noelia; Kahn, Andrew; Burns, Jane; Marsden, Alison

    2014-11-01

    Kawasaki Disease (KD) can result in coronary aneurysms in up to 25% of patients if not treated early putting patients at risk of thrombus formation, myocardial infarction and sudden death. Clinical guidelines for administering anti-coagulation therapy currently rely on anatomy alone. Previous studies including patient specific modeling and computer simulations in KD patients have suggested that hemodynamic data can predict regions susceptible to thrombus formation. In particular, high Particle Residence Time gradient (PRTg) regions have shown to correlate with regions of thrombus formation. Transluminal Attenuation Gradient (TAG) is determined from the change in radiological attenuation per vessel length. TAG has been used for characterizing coronary artery stenoses, however this approach has not yet been used in aneurysmal vessels. The aim of this study is to analyze the correlation between TAG and PRTg in KD patients with aneurysms and evaluate the use of TAG as an index to quantify thrombotic risk. Patient specific anatomic models for fluids simulations were constructed from CT angiographic image data from 3 KD aneurysm patients and one normal control. TAG values for the aneurysm patients were markedly lower than for the non-aneurysmal patient (mean -18.38 vs. -2). In addition, TAG values were compared to PRTg obtained for each patient. Thrombotic risk stratification for KD aneurysms may be improved by incorporating TAG and should be evaluated in future prospective studies.

  18. The origin and significance of secondary flows in the aortic arch.

    Science.gov (United States)

    Black, M M; Hose, D R; Lawford, P V

    1995-01-01

    This paper comprises a study of the secondary flow patterns that can develop in the human aortic arch. Clinical evidence of these secondary flows has been obtained by Kilner et al. using magnetic resonance velocity mapping techniques. Some of their results are presented for comparison in this paper. Four difference parametric models of the aortic arch have been analysed using computational fluid dynamic techniques. Both steady and transient flow conditions have been considered and two different commercially available software packages were used, namely FIDAP and FLOTRAN. A satisfactory comparison of the theoretical analysis with the results, both in vivo and in vitro, obtained by Kilner et al. for their out-of-plane inlet model was found. The theoretical analysis can now be extended to analyse the effect of different configurations and orientations of artificial aortic valves on the resulting aortic arch flow patterns.

  19. Idiopathic thoracic aortic aneurysm at pediatric age.

    Science.gov (United States)

    Marín-Manzano, E; González-de-Olano, D; Haurie-Girelli, J; Herráiz-Sarachaga, J I; Bermúdez-Cañete, R; Tamariz-Martel, A; Cuesta-Gimeno, C; Pérez-de-León, J

    2009-03-01

    A 6-year-old-boy presented with epigastric pain and vomiting over 1 year. Chest X-ray and esophagogastric transit showed a mediastinal mass. A chest computerized tomography angiogram demonstrated a descending thoracic aortic aneurysm. Analytical determinations carried out were all negative. The aneurysm was surgically repaired using a Dacron patch. The anatomopathological study described atherosclerotic lesions with calcifications, compatible with an atherosclerotic aneurysm wall. Aneurysms are uncommon in the pediatric population. Usually, no pathogenesis can be determined, and thus, such cases are grouped as idiopathic. Direct repair with or without patch is a therapeutic alternative in pediatric aneurysms and can allow the growth of the aortic circumference.

  20. Combined treatment for complex intracranial aneurysm

    Directory of Open Access Journals (Sweden)

    Chiriac A.

    2015-06-01

    Full Text Available Complex aneurysms often cannot be completely excluded by a single approaches. Today successful treatment of these lesions requires a combination between microsurgical and endovascular techniques. Planning of combined treatment require a very good understanding of aneurysm anatomy and a close collaboration between neurosurgeon and neuroendovascular interventionist. Endovascular coiling can usually be used as early treatment for a partially aneurysm occlusion including the ruptured area and followed by definitive clipping. On the other hand microsurgical clipping also can be used as first treatment for complex aneurysm neck reconstruction, allowing successful secondary placement of coils inside the remnant aneurysm sac

  1. Aneurysmal wall enhancement and perianeurysmal edema after endovascular treatment of unruptured cerebral aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Su, I. Chang [Toronto Western Hospital, Division of Neuroradiology, Department of Medical Imaging, Toronto, ON (Canada); Taipei Cathay General Hospital, Division of Neurosurgery, Department of Surgery, Taipei (China); Willinsky, Robert A.; Agid, Ronit [Toronto Western Hospital, Division of Neuroradiology, Department of Medical Imaging, Toronto, ON (Canada); Fanning, Noel F. [Cork University Hospital, Department of Interventional Neuroradiology, Cork (Ireland)

    2014-06-15

    Perianeurysmal edema and aneurysm wall enhancement are previously described phenomenon after coil embolization attributed to inflammatory reaction. We aimed to demonstrate the prevalence and natural course of these phenomena in unruptured aneurysms after endovascular treatment and to identify factors that contributed to their development. We performed a retrospective analysis of consecutively treated unruptured aneurysms between January 2000 and December 2011. The presence and evolution of wall enhancement and perianeurysmal edema on MRI after endovascular treatment were analyzed. Variable factors were compared among aneurysms with and without edema. One hundred thirty-two unruptured aneurysms in 124 patients underwent endovascular treatment. Eighty-five (64.4 %) aneurysms had wall enhancement, and 9 (6.8 %) aneurysms had perianeurysmal brain edema. Wall enhancement tends to persist for years with two patterns identified. Larger aneurysms and brain-embedded aneurysms were significantly associated with wall enhancement. In all edema cases, the aneurysms were embedded within the brain and had wall enhancement. Progressive thickening of wall enhancement was significantly associated with edema. Edema can be symptomatic when in eloquent brain and stabilizes or resolves over the years. Our study demonstrates the prevalence and some appreciation of the natural history of aneurysmal wall enhancement and perianeurysmal brain edema following endovascular treatment of unruptured aneurysms. Aneurysmal wall enhancement is a common phenomenon while perianeurysmal edema is rare. These phenomena are likely related to the presence of inflammatory reaction near the aneurysmal wall. Both phenomena are usually asymptomatic and self-limited, and prophylactic treatment is not recommended. (orig.)

  2. In-plane elastic stability of fixed parabolic shallow arches

    Institute of Scientific and Technical Information of China (English)

    CAI JianGuo; FENG Jian; CHEN Yao; HUANG LiFeng

    2009-01-01

    The nonlinear behavior of fixed parabolic shallow arches subjected to a vertical uniform load is inves-tigated to evaluate the in-plane buckling load. The virtual work principle method is used to establish the non-linear equilibrium and buckling equations. Analytical solutions for the non-linear in-plane sym-metric snap-through and antisymmetric bifurcation buckling loads are obtained. Based on the least square method, an approximation for the symmetric buckling load of fixed parabolic arch is proposedto simplify the solution process. And the relation between modified slenderness and buckling modes are discussed. Comparisons with the results of finite element analysis demonstrate that the solutions are accurate. A cable-arch structure is presented to improve the in-plane stability of parabolic arches. The comparison of buckling loads between cable-arch systems and arches only show that the effect of cables becomes more evident with the increase of arch's modified slenderness.

  3. Behaviour of Steel Arch Stabilized by a Textile Membrane

    Science.gov (United States)

    Svoboda, O.; Machacek, J.

    2015-11-01

    Behaviour of the slender steel arch supporting textile membranes in a membrane structure with respect to in-plane and out-of plane stability is investigated in the paper. In the last decades the textile membranes have been widely used to cover both common and exclusive structures due to progress in new membrane materials with eminent properties. Nevertheless, complex analysis of such membranes in interaction with steel structure (carbon/stainless steel perimeter or supporting elements) is rather demanding, even with specialized software. Laboratory model of a large membrane structure simulating a shelter roof of a concert stage was tested and the resulting stress/deflection values are presented. The model of a reasonable size was provided with prestressed membrane of PVC coated polyester fabric Ferrari® Précontraint 702S and tested under various loadings. The supporting steel structure consisted of two steel arch tubes from S355 grade steel and perimeter prestressed cables. The stability behaviour of the inner tube was the primary interest of the investigation. The SOFiSTiK software was used to analyse the structural behaviour in 3D. Numerical non-linear analysis of deflections and internal forces of the structure under symmetrical and asymmetrical loadings covers various membrane prestressing and specific boundary conditions. The numerical results are validated using test results. Finally, the preliminary recommendations for appropriate numerical modelling and stability design of the supporting structure are presented.

  4. Effect of dental arch convexity and type of archwire on frictional forces

    NARCIS (Netherlands)

    Fourie, Zacharias; Ozcan, Mutlu; Sandham, John

    2009-01-01

    Introduction: Friction measurements in orthodontics are often derived from models by using brackets placed on flat models with various straight wires. Dental arches are convex in some areas. The objectives of this study were to compare the frictional forces generated in conventional flat and convex

  5. 拱坝变形监测预报的随机森林模型及应用%Random forest model and application of arch dam′s deformation monitoring and prediction

    Institute of Scientific and Technical Information of China (English)

    罗浩; 郭盛勇; 包为民

    2016-01-01

    大坝变形预报对大坝运行安全评估起着至关重要的作用。传统模型预报精度不够、模拟效果不稳定;若大坝变形数据有异常值时,传统机器算法模型识别和处理异常值的灵活性很小,导致预报结果有偏差。为了解决这些问题,首次将随机森林算法运用到大坝变形监测领域,将大坝测点根据随机森林相似性矩阵分成若干个子集,针对每一个子集建立随机森林预测模型,分区建立预测模型更符合工程实际情况。选取拱坝变形作为研究对象,验证所建模型的适用性。结果表明,根据随机森林的相似性矩阵对大坝各测点的分区情况符合物理和工程实际意义,对各分区子集测点利用随机森林模型建立的预测模型,与支持向量机、BP神经网络模型相比,预测结果精度较高、模型稳定性好,为大坝变形监测提供了新思路。%Dam deformation prediction plays an important role in the safety assessment of dam operation .Traditional models lack forecasting precision and the simulation effect is not stable enough .Besides ,if abnormal values of dam deformation exist ,tradi‐tional machine algorithm model lacks the flexibility of dealing with these abnormal data ,which will lead to the deviation of the forecasting results .In order to solve these problems ,random forest algorithm was introduced to the field of dam deformation monitoring for the first time .Similarity matrix of random forest was applied to divide dam deformation monitoring points into several parts .Random forests prediction model was established for each part ,which will avoid the defects of traditional models such as modeling of single point or using the same model for all deformation monitoring points .Establishing forecasting model for different parts of dam was more in line with engineering practice .Deformation data of one arch dam was analyzed and the feasibility of random forest model was

  6. Multislice CT angiography of interrupted aortic arch

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Dong Hyun; Goo, Hyun Woo [Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea); Seo, Dong-Man; Yun, Tae-Jin; Park, Jeong-Jun [Asan Medical Center, University of Ulsan College of Medicine, Department of Paediatric Cardiac Surgery, Seoul (Korea); Park, In-Sook; Ko, Jae Kon; Kim, Young Hwee [Asan Medical Center, University of Ulsan College of Medicine, Department of Paediatric Cardiology, Seoul (Korea)

    2008-01-15

    Interrupted aortic arch (IAA) is defined as complete luminal and anatomic discontinuity between the ascending and descending aorta. Because almost all patients with IAA become critically ill during the neonatal period, they should undergo urgent corrective surgery. This clinical urgency necessitates a fast and accurate noninvasive diagnostic method. Although echocardiography remains the primary imaging tool for this purpose, it is not always sufficient for planning surgical correction of IAA, principally due to a limited acoustic window and the inexperience of imagers. In this context, multislice CT angiography is regarded as an appropriate imaging technique complementary to echocardiography because it is fast, accurate, and objective for the diagnosis of IAA. In this article we describe what cardiac radiologists should know about IAA in their clinical practice, including clinicopathological features, CT features with contemporary surgical methods and postoperative complications, and differentiation from coarctation of the aorta and aortic arch atresia. (orig.)

  7. The hemodynamics in intracranial aneurysm ruptured region with active contrast leakage during computed tomography angiography

    Science.gov (United States)

    Li, Ming-Lung; Wang, Yi-Chou; Liou, Tong-Miin; Lin, Chao-An

    2014-10-01

    Precise locations of rupture region under contrast agent leakage of five ruptured cerebral artery aneurysms during computed tomography angiography, which is to our knowledge for the first time, were successfully identified among 101 patients. These, together with numerical simulations based on the reconstructed aneurysmal models, were used to analyze hemodynamic parameters of aneurysms under different cardiac cyclic flow rates. For side wall type aneurysms, different inlet flow rates have mild influences on the shear stresses distributions. On the other hand, for branch type aneurysms, the predicted wall shear stress (WSS) correlates strongly with the increase of inlet vessel velocity. The mean and time averaged WSSes at rupture regions are found to be lower than those over the surface of the aneurysms. Also, the levels of the oscillatory shear index (OSI) are higher than the reported threshold value, supporting the assertion that high OSI correlates with rupture of the aneurysm. However, the present results also indicate that OSI level at the rupture region is relatively lower.

  8. Combined Visualization of Wall Thickness and Wall Shear Stress for the Evaluation of Aneurysms.

    Science.gov (United States)

    Glaßer, Sylvia; Lawonn, Kai; Hoffmann, Thomas; Skalej, Martin; Preim, Bernhard

    2014-12-01

    For an individual rupture risk assessment of aneurysms, the aneurysm's wall morphology and hemodynamics provide valuable information. Hemodynamic information is usually extracted via computational fluid dynamic (CFD) simulation on a previously extracted 3D aneurysm surface mesh or directly measured with 4D phase-contrast magnetic resonance imaging. In contrast, a noninvasive imaging technique that depicts the aneurysm wall in vivo is still not available. Our approach comprises an experiment, where intravascular ultrasound (IVUS) is employed to probe a dissected saccular aneurysm phantom, which we modeled from a porcine kidney artery. Then, we extracted a 3D surface mesh to gain the vessel wall thickness and hemodynamic information from a CFD simulation. Building on this, we developed a framework that depicts the inner and outer aneurysm wall with dedicated information about local thickness via distance ribbons. For both walls, a shading is adapted such that the inner wall as well as its distance to the outer wall is always perceivable. The exploration of the wall is further improved by combining it with hemodynamic information from the CFD simulation. Hence, the visual analysis comprises a brushing and linking concept for individual highlighting of pathologic areas. Also, a surface clustering is integrated to provide an automatic division of different aneurysm parts combined with a risk score depending on wall thickness and hemodynamic information. In general, our approach can be employed for vessel visualization purposes where an inner and outer wall has to be adequately represented.

  9. Vascular dynamics of a shape memory polymer foam aneurysm treatment technique.

    Science.gov (United States)

    Ortega, Jason; Maitland, Duncan; Wilson, Tom; Tsai, William; Savaş, Omer; Saloner, David

    2007-11-01

    The vascular dynamics of a shape memory polymer foam aneurysm treatment technique are assessed through the simulated treatment of a generic basilar aneurysm using coupled fluid dynamics and heat transfer calculations. The shape memory polymer foam, which expands to fill the aneurysm when heated, is modeled at three discrete stages of the treatment procedure. To estimate an upper bound for the maximum amount of thermal damage due to foam heating, a steady velocity is specified through the basilar artery, corresponding to a minimum physiological flow velocity over a cardiac cycle. During expansion, the foam alters the flow patterns within the aneurysm by shielding the aneurysm dome from a confined jet that issues from the basilar artery. The time scales for thermal damage to the artery walls and surrounding blood flow are computed from the temperature field. The flow through the post-treatment bifurcation is comprised of two counter-rotating vortex tubes that are located beneath the aneurysm neck and extend downstream into the outlet arteries. Beneath the aneurysm neck, a marked increase in the wall shear stress is observed due to the close proximity of the counter-rotating vortex tubes to the artery wall.

  10. NUMERICAL SIMULATION AND ANALYSIS ON THE HEMODYNAMICS OF AN ELASTIC ANEURYSM

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jun-wei; YIN Wen-yi; DING Guang-hong; YANG Xin-jian; SHI Wan-chao; ZHANG Xiao-long

    2008-01-01

    Intracranial aneurysms are pathological dilatations which endanger people's health. Hemodynamics is thought to be an important factor in the pathogenesis and treatment of aneurysms. To date, the bulk of investigations into hemodynamics have been conducted by making use of mathematically idealized models for rigid aneurysms and associated arteries. However the walls of aneurysms and associated arteries are elastic in vivo. This study shows the differences of the simulation between elastic and rigid wall models. The numerical simulation of elastic aneurysm model is made from a representative Digital Subtraction Angiography (DSA) image and calculated with CFD software to get the wall deformation and the velocity field. Then the results are analyzed. By comparing the simulation results of the two models from their velocity vectors and shear stress distribution, many differences can be noted. The main difference exists in the distribution of velocity magnitude at some sections, with one outlet having obviously off-center distribution for the elastic wall model. The currents of the distribution of wall shear stress along the wall of aneurysm simulated in rigid and elastic wall models were similar. But there were apparent differences between the two models on the values of wall shear stress especially at the neck of aneurysm. The off-center distribution of velocity magnitude affects the distribution of wall shear stress and the exchange of substance through the wall. The analysis demonstrated clearly that the results of 2-D elastic numerical simulation were in good agreement with the clinical and pathological practice. The results of this study play an important role in the formation, growth, rupture and prognosis of an aneurysm on clinic application.

  11. Building problem solving environments with the arches framework

    Energy Technology Data Exchange (ETDEWEB)

    Debardeleben, Nathan [Los Alamos National Laboratory; Sass, Ron [U NORTH CAROLINA; Stanzione, Jr., Daniel [ASU; Ligon, Ill, Walter [CLEMSON UNIV

    2009-01-01

    The computational problems that scientists face are rapidly escalating in size and scope. Moreover, the computer systems used to solve these problems are becoming significantly more complex than the familiar, well-understood sequential model on their desktops. While it is possible to re-train scientists to use emerging high-performance computing (HPC) models, it is much more effective to provide them with a higher-level programming environment that has been specialized to their particular domain. By fostering interaction between HPC specialists and the domain scientists, problem-solving environments (PSEs) provide a collaborative environment. A PSE environment allows scientists to focus on expressing their computational problem while the PSE and associated tools support mapping that domain-specific problem to a high-performance computing system. This article describes Arches, an object-oriented framework for building domain-specific PSEs. The framework was designed to support a wide range of problem domains and to be extensible to support very different high-performance computing targets. To demonstrate this flexibility, two PSEs have been developed from the Arches framework to solve problem in two different domains and target very different computing platforms. The Coven PSE supports parallel applications that require large-scale parallelism found in cost-effective Beowulf clusters. In contrast, RCADE targets FPGA-based reconfigurable computing and was originally designed to aid NASA Earth scientists studying satellite instrument data.

  12. Recurrent Pneumonia due to Double Aortic Arch

    Directory of Open Access Journals (Sweden)

    I. Sedighi

    2012-04-01

    Full Text Available Introduction: Pneumonia is one of the most common infections during childhood. In children with recurrent bacterial pneumonia complete evaluation for underlying factors is necessary. The most common underlying diseases include: antibody deficiencies , cystic fibrosis , tracheoesophageal fistula and increased pulmonary blood flow. Vascular ring and its pressure effect is a less common cause of stridor and recurrent pneumonia. Congenital abnormalities in aortic arch and main branches which form vascular ring around esophagus and trachea with variable pressure effect cause respiratory symptoms such as stridor , wheezing and recurrent pneumoniaCase Report: A 2 year old boy was admitted in our hospital with respiratory distress and cough . Chest x-Ray demonstrated right lobar pneumonia. He had history of stridor and wheezing from neonatal period and hospitalization due to pneumonia for four times. The patient received appropriate antibiotics. Despite fever and respiratory distress improvement, wheezing continued. Review of his medical documents showed fixed pressure effect on posterior aspect of esophagus in barium swallow. In CT angiography we confirmed double aortic arch.Conclusion: Double aortic arch is one of the causes of persistant respiratory symptom and recurrent pneumonia in children for which fluoroscopic barium swallow is the first non-invasive diagnostic method.(Sci J Hamadan Univ Med Sci 2012;19(1:70-74

  13. Effects of different medial arch support heights on rearfoot kinematics

    Science.gov (United States)

    Mayer, Frank; Baur, Heiner

    2017-01-01

    Background Foot orthoses are usually assumed to be effective by optimizing mechanically dynamic rearfoot configuration. However, the effect from a foot orthosis on kinematics that has been demonstrated scientifically has only been marginal. The aim of this study was to examine the effect of different heights in medial arch-supported foot orthoses on rear foot motion during gait. Methods Nineteen asymptomatic runners (36±11years, 180±5cm, 79±10kg; 41±22km/week) participated in the study. Trials were recorded at 3.1 mph (5 km/h) on a treadmill. Athletes walked barefoot and with 4 different not customized medial arch-supported foot orthoses of various arch heights (N:0 mm, M:30 mm, H:35 mm, E:40mm). Six infrared cameras and the `Oxford Foot Model´ were used to capture motion. The average stride in each condition was calculated from 50 gait cycles per condition. Eversion excursion and internal tibia rotation were analyzed. Descriptive statistics included calculating the mean ± SD and 95% CIs. Group differences by condition were analyzed by one factor (foot orthoses) repeated measures ANOVA (α = 0.05). Results Eversion excursion revealed the lowest values for N and highest for H (B:4.6°±2.2°; 95% CI [3.1;6.2]/N:4.0°±1.7°; [2.9;5.2]/M:5.2°±2.6°; [3.6;6.8]/H:6.2°±3.3°; [4.0;8.5]/E:5.1°±3.5°; [2.8;7.5]) (p>0.05). Range of internal tibia rotation was lowest with orthosis H and highest with E (B:13.3°±3.2°; 95% CI [11.0;15.6]/N:14.5°±7.2°; [9.2;19.6]/M:13.8°±5.0°; [10.8;16.8]/H:12.3°±4.3°; [9.0;15.6]/E:14.9°±5.0°; [11.5;18.3]) (p>0.05). Differences between conditions were small and the intrasubject variation high. Conclusion Our results indicate that different arch support heights have no systematic effect on eversion excursion or the range of internal tibia rotation and therefore might not exert a crucial influence on rear foot alignment during gait. PMID:28257426

  14. FLOOD DISCHARGE AND ENERGY DISSIPATION BY JETS FROM OUTLETS IN HIGH ARCH DAM

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this thesis, the downstream local rock-bed scour by multiple layered jets and by the collision of water jets in vertical and transverse directions were studied and the stability of the inverted arch cushion pool were analyzed. The velocity distribution of an aerated jet running dwon in the pool is obtained, a new method to calculate the scour depth by multiple layered jets and by the collision of water jets was proposed, and a muthematical model to forecast the critical downstream depth as a slab with various specific gravity destructions was established. The results were verified by experimental research on the hydrodynamic pressure produced at gaps of the inverted arch type of wate cushion pool and by using an advanced measurement and the imitation method experiments on forces at both arch spandrels were carried out to find their characteristics.

  15. Development of Image Segmentation Methods for Intracranial Aneurysms

    Directory of Open Access Journals (Sweden)

    Yuka Sen

    2013-01-01

    Full Text Available Though providing vital means for the visualization, diagnosis, and quantification of decision-making processes for the treatment of vascular pathologies, vascular segmentation remains a process that continues to be marred by numerous challenges. In this study, we validate eight aneurysms via the use of two existing segmentation methods; the Region Growing Threshold and Chan-Vese model. These methods were evaluated by comparison of the results obtained with a manual segmentation performed. Based upon this validation study, we propose a new Threshold-Based Level Set (TLS method in order to overcome the existing problems. With divergent methods of segmentation, we discovered that the volumes of the aneurysm models reached a maximum difference of 24%. The local artery anatomical shapes of the aneurysms were likewise found to significantly influence the results of these simulations. In contrast, however, the volume differences calculated via use of the TLS method remained at a relatively low figure, at only around 5%, thereby revealing the existence of inherent limitations in the application of cerebrovascular segmentation. The proposed TLS method holds the potential for utilisation in automatic aneurysm segmentation without the setting of a seed point or intensity threshold. This technique will further enable the segmentation of anatomically complex cerebrovascular shapes, thereby allowing for more accurate and efficient simulations of medical imagery.

  16. The influence of neck thrombus on clinical outcome and aneurysm morphology after endovascular aneurysm repair

    NARCIS (Netherlands)

    Goncalves, Frederico Bastos; Verhagen, Hence J. M.; Chinsakchai, Khamin; van Keulen, Jasper W.; Voute, Michiel T.; Zandvoort, Herman J.; Moll, Frans L.; van Herwaarden, Joost A.

    2012-01-01

    Objective: This study investigated the influence of significant aneurysm neck thrombus in clinical and morphologic outcomes after endovascular aneurysm repair (EVAR). Methods: The patient population was derived from a prospective EVAR database from two university institutions in The Netherlands from

  17. Oculomotor Paresis and Basilar Aneurysm

    OpenAIRE

    J Gordon Millichap

    1992-01-01

    The clinical and pathologic findings in a 10 month old girl with congenital heart diseasewho died after rupture of a congenital distal basilar artery aneurysm are reported from the University of Connecticut Health Center, Farmington, CT and the Children’s Hospital of Philadelphia, PA.

  18. [Abdominal aortic aneurysm treated by endovascular surgery: a case report].

    Science.gov (United States)

    Alconero-Camarero, Ana Rosa; Cobo-Sánchez, José Luis; Casaus-Pérez, María; García-Campo, María Elena; García-Zarrabeitia, María José; Calvo-Diez, Marta; Mirones-Valdeolivas, Luz Elena

    2008-01-01

    An aneurysm is an abnormal dilation or irreversible convex of a portion of an artery. The most common site of aneurysms is the abdominal aorta and their appearance is often due to degeneration of the arterial wall, associated with atherosclerosis and favored by risk factors such as smoking and hypertension, among others. Left untreated, aneurysm of the abdominal aorta usually leads to rupture. Treatment is surgical, consisting of the introduction of a prosthesis, composed basically of a stent and an introducer, into the aorta. We report the case of a person diagnosed with abdominal aortic aneurysm in a routine examination who was admitted for ambulatory surgical treatment. We designed a nursing care plan, following Virginia Henderson's conceptual model. The care plan was divided into 2 parts, a first preoperative phase and a second postimplantation or monitoring phase. The care plan contained the principal nursing diagnoses, based on the taxonomies of the North American Nursing Diagnosis Association (NANDA), nursing interventions classification (NIC) and nursing outcomes classifications (NOC), and collaboration problems/potential complications. The patient was discharged to home after contact was made with his reference nurse in the primary health center, since during the hospital phase, some NOC indicators remained unresolved.

  19. Elastic energy within the human plantar aponeurosis contributes to arch shortening during the push-off phase of running.

    Science.gov (United States)

    Wager, Justin C; Challis, John H

    2016-03-21

    During locomotion, the lower limb tendons undergo stretch and recoil, functioning like springs that recycle energy with each step. Cadaveric testing has demonstrated that the arch of the foot operates in this capacity during simple loading, yet it remains unclear whether this function exists during locomotion. In this study, one of the arch׳s passive elastic tissues (the plantar aponeurosis; PA) was investigated to glean insights about it and the entire arch of the foot during running. Subject specific computer models of the foot were driven using the kinematics of eight subjects running at 3.1m/s using two initial contact patterns (rearfoot and non-rearfoot). These models were used to estimate PA strain, force, and elastic energy storage during the stance phase. To examine the release of stored energy, the foot joint moments, powers, and work created by the PA were computed. Mean elastic energy stored in the PA was 3.1±1.6J, which was comparable to in situ testing values. Changes to the initial contact pattern did not change elastic energy storage or late stance PA function, but did alter PA pre-tensioning and function during early stance. In both initial contact patterns conditions, the PA power was positive during late stance, which reveals that the release of the stored elastic energy assists with shortening of the arch during push-off. As the PA is just one of the arch׳s passive elastic tissues, the entire arch may store additional energy and impact the metabolic cost of running.

  20. 特克斯河山口引水枢纽的 引水防沙设计及试验研究%Dynamic test and study on the integral body and model with transverse joint of Xiaowan High Arch Dam

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    通过特克斯河山口引水枢纽的试验研究,解决了常遇洪水低水位运行时河流两岸的引水问题,优化了水平悬板等结构形式,收到了较好的引水防沙效果,为悬板分层式引水枢纽工程设计提供了新经验%The dynamic test on the earthquake response of the integral dam body and model with transverse joint for Xiaowan High Arch Dam was made. In consideration that the dynamic test on the model with transverse joint falls into non-linear category, it is more sensitive to the initial condition of static action so that the test includes reservoir with a length of three times dam height. The test on expansion transverse joint was made in two working conditions. Firstly three expansion transverse joints were set up in the arch-crown beam and top arch, about 1/4 arc length of right and left banks. Then five transverse joints were increased to make dynamic test. The test showed that under the working condition of normal high water level, the transverse joint of dam body under the action of earthquake opens indistinctly. But under the low water level, the transverse joint clearly opens because of the reduction of static pressure. The dynamic tensile stress of dam body obviously reduces and the dynamic beam stress increases obviously. The initial condition of the transverse joints of dam body will bring big impact on the opening of transverse joint. On the basis of the designed reinforcement, the test showed that the opening of transverse joint reduced about 20%.

  1. In-plane elastic stability of fixed parabolic shallow arches

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The nonlinear behavior of fixed parabolic shallow arches subjected to a vertical uniform load is inves- tigated to evaluate the in-plane buckling load. The virtual work principle method is used to establish the non-linear equilibrium and buckling equations. Analytical solutions for the non-linear in-plane sym- metric snap-through and antisymmetric bifurcation buckling loads are obtained. Based on the least square method, an approximation for the symmetric buckling load of fixed parabolic arch is proposed to simplify the solution process. And the relation between modified slenderness and buckling modes are discussed. Comparisons with the results of finite element analysis demonstrate that the solutions are accurate. A cable-arch structure is presented to improve the in-plane stability of parabolic arches. The comparison of buckling loads between cable-arch systems and arches only show that the effect of cables becomes more evident with the increase of arch’s modified slenderness.

  2. Accuracy of impressions obtained with dual-arch trays.

    Science.gov (United States)

    Wöstmann, Bernd; Rehmann, Peter; Balkenhol, Markus

    2009-01-01

    This study aimed to analyze the accuracy resulting from dual-arch impressions when compared to conventional impressions in complex preparations (ie, inlay and partial crown). One hundred eighty impressions were made using two different dual-arch trays; conventional trays served as the control. The accuracy of the dies obtained (Fuji-Rock EP, GC Europe) was assessed indirectly from the change of 59 transversal dimensions. Statistical analysis (t test, analysis of variance) revealed that less rigid dual-arch trays performed better than rigid ones. Though the inlay preparation was more difficult to reproduce with dual-arch trays, it can be concluded that the accuracy obtainable with nonrigid dual-arch trays is comparable to impressions taken from full-arch trays.

  3. Aneurysm occlusion in elderly patients with aneurysmal subarachnoid hemorrhage : a cost-utility analysis

    NARCIS (Netherlands)

    Koffijberg, H.; Rinkel, G.J.; Buskens, E.

    2011-01-01

    BACKGROUND: Aneurysm occlusion after subarachnoid hemorrhage (SAH) aims to improve outcome by reducing the rebleeding risk. With increasing age overall prognosis decreases and the complications of aneurysm occlusion increase. The balance of risks for aneurysm occlusion in elderly SAH patients in dif

  4. Aneurysm occlusion in elderly patients with aneurysmal subarachnoid haemorrhage : a cost-utility analysis

    NARCIS (Netherlands)

    Koffijberg, H.; Buskens, E.; Rinkel, G. J. E.

    2011-01-01

    Background Aneurysm occlusion after subarachnoid haemorrhage (SAH) aims to improve outcome by reducing the rebleeding risk. With increasing age, overall prognosis decreases, and the complications of aneurysm occlusion increase. The balance of risks for aneurysm occlusion in elderly SAH patients in d

  5. General Considerations of Ruptured Abdominal Aortic Aneurysm: Ruptured Abdominal Aortic Aneurysm

    OpenAIRE

    Lee, Chung Won; Bae, Miju; Chung, Sung Woon

    2015-01-01

    Although development of surgical technique and critical care, ruptured abdominal aortic aneurysm still carries a high mortality. In order to obtain good results, various efforts have been attempted. This paper reviews initial management of ruptured abdominal aortic aneurysm and discuss the key point open surgical repair and endovascular aneurysm repair.

  6. Aortic arch blunt injury in front-seat passenger.

    Science.gov (United States)

    Türkmen, Nursel; Eren, Bülent; Aydin, Şule Akköse

    2013-10-01

    Aortic arch blunt injury has highly lethal nature. Because the physical examination findings are subtle, immediate medical evaluation is very important. The case was a 72-year-old woman. Massive haemorrhage in the left haemotorax, contusion area in the left lung and a traumatic transection of the distal aortic arch was observed during autopsy. We described intersting autopsy case of aortic arch blunt injury.

  7. Critical thrombotic obstruction of transverse aortic arch in a neonate

    Directory of Open Access Journals (Sweden)

    Karunakar Vadlamudi

    2015-01-01

    Full Text Available A 3-day-old neonate presented with features suggestive of coarctation of aorta. Echocardiography showed a large organized thrombus in the transverse arch causing obstruction to theaortic arch and carotids with partial recanalization. Patient underwent surgical thromboendarterectomy with arch reconstruction. The evaluation did not reveal any hematological abnormalities and suspected to be due to fetal thromboembolism. Patient improved well, and no neurological deficits were observed during follow-up.

  8. Isolated iliac artery aneurysms with associated hydronephrosis.

    LENUS (Irish Health Repository)

    O'Driscoll, D

    2012-02-03

    An isolated iliac artery aneurysm is where there is aneurysmal dilatation of one or more branches of the iliac system, with no associated dilatation of the aorta. Such aneurysms are rare and comprise 1% of all intra-abdominal aneurysms. The signs and symptoms of such an aneurysm are influenced by its concealed location within the bony pelvis. Awareness of these special characteristics improves the chances of early diagnosis and proper treatment before possible rupture. We present the clinical and radiological features of three such aneurysms. Ultrasound was the first imaging modality to be performed. Ipsilateral hydronephrosis was demonstrated in each case, this lead to imaging the pelvis and the correct diagnosis. We review the clinical and radiological literature and conclude that the pelvis should be imaged in all cases of unexplained hydronephrosis.

  9. Experiment Study on Normal Section Bearing Capacity of Masonry Arch?Bridge Reinforced with Composite Arch Ring%复合拱圈加固圬工拱桥正截面承载力试验研究

    Institute of Scientific and Technical Information of China (English)

    乔文靖; 孙克东; 李成华

    2016-01-01

    In order to research on normal section bearing capacity of masonry arch bridge that is strengthened by composite arch ring under cracks of original arch ring,the three sectional models of masonry arch bridge strengthened by composite arch circle are designed,considering the cracks of original arch ring and the mechanical properties of different materials,numerical simulation and experimental research are carried out based on common stress and deformation coordination between the original arch ring and reinforced layer.The results show:When the crack width is 1/4 original arch width,the bearing capacity is 14.5% less than the non crack arch segment;When the crack width is 1/2 original arch width,the bearing capacity is 3 7 .3% less than the non crack arch segment;The bearing capacity decreases in proportion of the increased crack width.%为了研究原拱圈在裂缝作用下,复合拱圈加固圬工拱桥的正截面承载力计算问题,建立了3个复合拱圈加固圬工拱桥节段模型,考虑原拱圈的裂缝和不同材料的力学性能,基于原拱圈和加固层共同受力和协调变形,进行了数值模拟和试验研究.结果表明:当裂缝宽度为原拱圈宽度1/4时,实测承载力比无裂缝拱段减少了14.5%;当裂缝宽度为原拱圈宽度1/2时,实测承载力比无裂缝拱段减少了37.3%,裂缝增大使承载力成比例减小.

  10. Vascular dysfunctions in the isolated aorta of double-transgenic hypertensive mice developing aortic aneurysm

    DEFF Research Database (Denmark)

    Waeckel, L.; Badier-Commander, C.; Damery, T.

    2015-01-01

    Angiotensin-II and oxidative stress are involved in the genesis of aortic aneurysms, a phenomenon exacerbated by endothelial nitric oxide synthase (eNOS) deletion or uncoupling. The purpose of this work was to study the endothelial function in wild-type C57BL/6 (BL) and transgenic mice expressing...... not affected in BLSL and AR. However, in ARSL, endothelium-dependent relaxations (acetylcholine, UK-14304) were significantly reduced, and this dysfunction was similar in aortae without or with aneurysms. The endothelial impairment was unaffected by catalase, superoxide-dismutase mimetic, radical scavengers......, cyclooxygenase inhibition, or TP-receptor blockade and could not be attributed to sGC oxidation. Thus, ARSL is a severe hypertension model developing aortic aneurysm. A vascular dysfunction, involving both endothelial (reduced role of NO) and smooth muscle cells, precedes aneurysms formation and, paradoxically...

  11. Right aortic arch with coarctation in Chinese children

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Zhu; Aimin, Sun [Shanghai Children' s Medical Center, Department of Radiology, Shanghai (China)

    2008-05-15

    Because of the rarity of right aortic arch coarctation there are few reports of large groups of patients. To characterize the frequency and type of right aortic arch coarctation in a large group of pediatric patients. From June 1997 through May 2007, 11,276 consecutive children with congenital heart disease underwent multidetector CT (MDCT), MRI or angiocardiography examination. All children with a right aortic arch or coarctation were reviewed. Right aortic arch coarctation was found in 11 children representing 0.1% of the total group of 11,276 children, 1.7% of 658 children with native coarctations and 2.3% of 473 children with a right aortic arch. Among the 11 patients, 6 had long-segment narrowing and 7 had an aberrant left subclavian artery. MDCT, MRI and angiocardiography are reliable imaging techniques for the diagnosis of right aortic arch and coarctation. Our findings showed that the pattern of right aortic arch coarctation was different from that of left aortic arch coarctation, suggesting that they are different etiological entities. The pivotal role possibly played by flow dynamics in the development of right aortic arch coarctation is discussed. (orig.)

  12. The seismic response of concrete arch bridges (with focus on the Bixby Creek bridge Carmel, California)

    Energy Technology Data Exchange (ETDEWEB)

    Hoehler, M; McCallen, D; Noble, C

    1999-06-01

    The analysis, and subsequent retrofit, of concrete arch bridges during recent years has relied heavily on the use of computational simulation. For seismic analysis in particular, computer simulation, typically utilizing linear approximations of structural behavior, has become standard practice. This report presents the results of a comprehensive study of the significance of model sophistication (i.e. linear vs. nonlinear) and pertinent modeling assumptions on the dynamic response of concrete arch bridges. The study uses the Bixby Creek Bridge, located in California, as a case study. In addition to presenting general recommendations for analysis of this class of structures, this report provides an independent evaluation of the proposed seismic retrofit for the Bixby Creek Bridge. Results from the study clearly illustrate a reduction of displacement drifts and redistribution of member forces brought on by the inclusion of material nonlinearity. The analyses demonstrate that accurate modeling of expansion joints, for the Bixby Creek Bridge in particular, is critical to achieve representative modal and transient behavior. The inclusion of near-field displacement pulses in ground motion records was shown to significantly increase demand on the relatively softer, longer period Bixby Creek Bridge arch. Stiffer, shorter period arches, however, are more likely susceptible to variable support motions arising from the canyon topography typical for this class of bridges.

  13. Comparison of maxillary and mandibular dental arch forms by studying Fourier series developed from mathematically estimated dentitions.

    Science.gov (United States)

    Mikami, Hiroko; Nakatsuka, Michiko; Iwai, Yasutomo

    2010-11-01

    We conducted a Fourier analysis on data obtained using correlation and principal component analyses of parallel-standardized dental study models; both maxillary and mandibular dental arches were predominantly round square in shape. The present study compared and determined the contribution ratio and reproducible coefficients of amplitudes (factors affecting dental arch forms), and demonstrated that the 1st to 4th and the 1st to 6th Fourier harmonics reproduced maxillary and mandibular dental arch forms, respectively. The correlation analyses of the constant term and amplitudes demonstrated that significant differences in the 2nd harmonic amplitude was strongly correlated with the curvature of anterior teeth and the length-to-width ratio in maxillary dentitions. By comparison of the constant term and amplitudes between different arch types, we did not observe significant differences in the constant term and the 1st amplitude of maxillary dentitions and in constant term and all amplitudes of mandibular dentitions. Nevertheless, the study revealed high contribution ratios of the 1st (in mandibular dentitions) and the 2nd (in maxillary dentitions) amplitudes essentially affecting the reproducibility of arch forms. The 1st amplitudes demonstrated a bow-like arrangement of all arch types, while the 2nd amplitudes adjusted the anterior-teeth curvature and in particular demonstrated the length-to-width ratio of maxillary dentitions. The 3rd and the 4th amplitudes were also determinants of the anterior-teeth curvature of maxillary dentitions. The 6th amplitude was necessary for reproduction, but showed no difference between varying mandibular dental arch types. Collectively, we conclude that the establishment of a Fourier series significantly reproduced maxillary but not mandibular dental arch forms.

  14. [Late paraparesis as a postoperative complication in a patient undergoing the repair of a double aortic aneurysm].

    Science.gov (United States)

    Bonome González, C; Alvarez Refojo, F; Fernández Carballal, F; Rodríguez Alvarez, R

    1993-01-01

    We report a case of a fifty-seven (57)-years old man undergoing elective surgery of a thoracoabdominal and aortoiliac aneurysm in a single surgical time. The patients is operated undergoing general anesthetic combined with thoracic epidural blockade, and it was done two aortic cross-clamping: one to five cm of the aortic arch and the other to the infrarenal level. The most important intraoperative complications were during the thoracic aortic cross-clamping and the most important postoperative complication was related 48 hours later, to paraparesis after a hypotension episode what improved with rehabilitation treatment.

  15. Study on multi-scheme analysis and evaluation method for concrete sequence placement of high arch dam

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A complete scheme for solving the key scientific problems of how to make concrete sequence placement scheme of high arch dam reasonable and feasible and how to meet the need of construction process was presented.First,based on a coupling analysis of concrete sequence placement system of high arch dam,a mathematical model considering complex construction constraints was established.Second,a multi-scheme computational analysis method for concrete sequence placement of high arch dam was proposed based on dynamic simulation.Third,a multi-scheme evaluation method for concrete sequence placement was put forward based on analytic hierarchy process.Fourth,feedback guidance for progress control and management in the high arch dam construction process was proposed.Finally,these methods were applied to a practical project to show that the methods can analyze and evaluate multi-scheme for concrete sequence placement of high arch dam effectively,optimize the process of dam concrete sequence placement,and recommend engineering measures.These methods provide new theoretical principles and technical measures for real-time progress control in the high arch dam construction.

  16. Management of splenic artery aneurysm associatedwithextrahepaticportal veinobstruction

    Institute of Scientific and Technical Information of China (English)

    Pramod Kumar Mishra; Sundeep Singh Saluja; Ashok K Sharma; Premanand Pattnaik

    2012-01-01

    BACKGROUND: Splenic artery aneurysms although rare are clinically signiifcant in view of their propensity for spontaneous rupture and life-threatening bleeding. While portal hypertension is an important etiological factor, the majority of reported cases are secondary to cirrhosis of the liver. We report three cases of splenic artery aneurysms associated with extrahepatic portal vein obstruction and discuss their management. METHODS: The records of three patients of splenic artery aneurysm associated with extrahepatic portal vein obstruction managed from 2003 to 2010 were reviewed retrospectively. The clinical presentation, surgical treatment and outcome were analyzed. RESULTS:  The aneurysm was >3 cm in all patients. The clinical symptoms were secondary to extrahepatic portal vein obstruction (hematemesis in two, portal biliopathy in two) while the aneurysm was asymptomatic. Doppler ultrasound demonstrated aneurysms in all patients. A proximal splenorenal shunt was performed in two patients with excision of the aneurysm in one patient and ligation of the aneurysm in another one. The third patient had the splenic vein replaced by collaterals and hence underwent splenectomy with aneurysmectomy. All patients had an uneventful post-operative course. CONCLUSIONS: Splenic artery aneurysms are associated with extrahepatic portal vein obstruction. Surgery is the mainstay of treatment. Although technically dififcult, it can be safely performed in an experienced center with minimal morbidity and good outcome.

  17. Pathomechanisms and treatment of pediatric aneurysms.

    Science.gov (United States)

    Krings, Timo; Geibprasert, Sasikhan; terBrugge, Karel G

    2010-10-01

    Pediatric aneurysms are rare diseases distinct from classical adult aneurysms and therefore require different treatment strategies. Apart from saccular aneurysms that are more commonly found in older children, three major pathomechanisms may be encountered: trauma, infection, and dissection. The posterior circulation and more distal locations are more commonly encountered in children compared to adults, and there is an overall male predominance. Clinical findings are not only confined to subarachnoid hemorrhage but may also comprise mass effects, headaches or neurological deficits. In traumatic aneurysms, the skull base and distal anterior communicating artery are commonly affected, and the hemorrhage occurs often delayed (2-4 weeks following the initial trauma). Infectious aneurysms are mostly bacterial in origin, and hemorrhage occurs early after a septic embolic shower. Dissecting aneurysms are the most often encountered aneurysm type in children and can lead to mass effect, hemorrhage, or ischemia depending on the fate of the intramural hematoma. Treatment strategies in pediatric aneurysms include endosaccular coil treatment only for the "classical berry-type" aneurysms; in the other instances, parent vessel occlusion, flow reversal, surgical options, or a combined treatment with bypass and parent vessel occlusion have to be contemplated.

  18. Endovascular treatment for pediatric intracranial aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Xianli; Jiang, Chuhan; Li, Youxiang; Yang, Xinjian; Wu, Zhongxue [Capital Medical University, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Beijing, Hebei (China)

    2009-11-15

    The purpose of this study is to report the characteristics and outcomes of pediatric patients with intracranial aneurysms. From 1998 to 2005, 25 pediatric patients (aged {<=}17 years) with intracranial aneurysm were treated at our institute. Eleven of 25 patients had subarachnoid hemorrhage. In ten patients, the aneurysm was an incidental finding. One patient presented with cranial nerves dysfunction and three with neurological deficits. The locations of the aneurysms were as follows: vertebral artery (VA; n = 9), middle cerebral artery (MCA; n = 5), posterior cerebral artery (PCA; n = 4), basilar artery (BA; n = 2), anterior communicating artery (n = 2), anterior cerebral artery (n = 2), and internal carotid artery (n = 1). Five patients were treated with selective embolization with coils. Sixteen patients were treated with parent vessel occlusion (PVO). Eight PVOs were performed with balloons and eight were performed with coils. One patient with a VA aneurysm was spontaneously thrombosed 4 days after the initial diagnostic angiogram. In three patients treated with stent alone or stent-assisted coiling, one with BA trunk aneurysm died. One aneurismal recurrence occurred and was retreated. At a mean follow-up duration of 23.5 months, 96% of patients had a Glasgow Outcome Scale score of 4 or 5. Pediatric intracranial aneurysms occur more commonly in male patients and have a predilection for the VA, PCA, and MCA. PVO is an effective and safe treatment for fusiform aneurysms. Basilar trunk fusiform aneurysms were difficult to treat and were associated with a high mortality rate. (orig.)

  19. Computational Fluid Dynamics Study of Bifurcation Aneurysms Treated with Pipeline Embolization Device: Side Branch Diameter Study.

    Science.gov (United States)

    Tang, Abraham Yik-Sau; Chung, Wai-Choi; Liu, Eric Tian-Yang; Qu, Jie-Qiong; Tsang, Anderson Chun-On; Leung, Gilberto Ka-Kit; Leung, Kar-Ming; Yu, Alfred Cheuk-Hang; Chow, Kwok-Wing

    An intracranial aneurysm, abnormal swelling of the cerebral artery, may lead to undesirable rates of mortality and morbidity upon rupture. Endovascular treatment involves the deployment of a flow-diverting stent that covers the aneurysm orifice, thereby reducing the blood flow into the aneurysm and mitigating the risk of rupture. In this study, computational fluid dynamics analysis is performed on a bifurcation model to investigate the change in hemodynamics with various side branch diameters. The condition after the deployment of a pipeline embolization device is also simulated. Hemodynamic factors such as flow velocity, pressure, and wall shear stress are studied. Aneurysms with a larger side branch vessel might have greater risk after treatment in terms of hemodynamics. Although a stent could lead to flow reduction entering the aneurysm, it would drastically alter the flow rate inside the side branch vessel. This may result in side-branch hypoperfusion subsequent to stenting. In addition, two patient-specific bifurcation aneurysms are tested, and the results show good agreement with the idealized models. Furthermore, the peripheral resistance of downstream vessels is investigated by varying the outlet pressure conditions. This quantitative analysis can assist in treatment planning and therapeutic decision-making.

  20. Pulmonary artery aneurysm with patent arterial duct: resection of aneurysm and ductal division.

    Science.gov (United States)

    Tefera, Endale; Teodori, Michael

    2013-10-01

    Congenital or acquired aneurysm of the pulmonary artery (PA) is rare. Although aneurysms are described following surgical treatment of patent ductus arteriosus (PDA), occurrence of this lesion in association with PDA without previous surgery is extremely uncommon. An eight-year-old patient with PDA and aneurysm of the main PA is described in this report. Clinical diagnosis of PDA was made upon presentation. Diagnosis of PA aneurysm was suspected on chest x-ray and was confirmed on transthoracic echocardiography. Successful surgical resection of the aneurysm and division of the duct were performed under cardiopulmonary bypass. The patient did well on follow-up both from clinical and echocardiographic point of view.

  1. [A case of successful treatment of concomitant ruptured intracranial aneurysm and visceral aneurysm].

    Science.gov (United States)

    Diogo, Cláudia; Baltazar, José; Fernandes, Mário

    2012-01-01

    The association between intracranial and visceral aneurysms is very rare, with a bad prognosis. The rupture usually appears in the Emergency Room, and it implies an immediate treatment. We describe the case of a woman with rupture of an anterior communicant artery aneurysm and rupture of a pancreatic duodenal artery aneurysm. The actuation of all specialties allowed the direct surgical treatment of the visceral aneurysm, without the aggravation of the cerebral hemorrhage that the eventual Aorta Artery clamping could provoke. The maintenance of the hemodynamic stability was essential for the posterior treatment of the intracranial aneurysm.

  2. Endovascular Aneurysm Repair in HIV Patients with Ruptured Abdominal Aneurysm and Low CD4

    Directory of Open Access Journals (Sweden)

    Saranat Orrapin

    2016-01-01

    Full Text Available We report two HIV infected patients with ruptured abdominal aneurysm by using endovascular aneurysm repair (EVAR technique. A 59-year-old Thai man had a ruptured abdominal aortic aneurysm and a 57-year-old man had a ruptured iliac artery aneurysm. Both patients had a CD4 level below 200 μ/L indicating a low immune status at admission. They were treated by EVAR. Neither patient had any complications in 3 months postoperatively. EVAR may have a role in HIV patients with ruptured abdominal aneurysm together with very low immunity.

  3. Towards Predicting Patient-Specific Flow-Diverter Treatment Outcomes for Bifurcation Aneurysms: From Implantation Rehearsal to Virtual Angiograms.

    Science.gov (United States)

    Peach, T W; Spranger, K; Ventikos, Y

    2016-01-01

    Despite accounting for the majority of all cerebral aneurysm cases, bifurcation aneurysms present many challenges to standard endovascular treatment techniques. This study examines the treatment of bifurcation aneurysms endovascularly with flow-diverting stents and presents an integrative computational modeling suite allowing for rehearsing all aspects of the treatment. Six bifurcation aneurysms are virtually treated with 70% porosity flow-diverters. Substantial reduction (>50%) in aneurysm inflow due to device deployment is predicted in addition to reductions in peak and average aneurysm wall shear stress to values considered physiologically normal. The subsequent impact of flow-diverter deployment on daughter vessels that are jailed by the device is investigated further, with a number of simulations conducted with increased outlet pressure conditions at jailed vessels. Increased outlet pressures at jailed daughter vessels are found to have little effect on device-induced aneurysm inflow reduction, but large variation (13-86%) is seen in the resulting reduction in daughter vessel flow rate. Finally, we propose a potentially powerful approach for validation of such models, by introducing an angiographic contrast model, with contrast transport modeled both before and after virtual treatment. Virtual angiograms and contrast residence curves are created, which offer unique clinical relevance and the potential for future in vivo verification of simulated results.

  4. Cyclic behavior test of a new double-arch steel gate

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new double-arch structure for the gate used as tidal barrage and sluice was adopted in Caoe River Dam in China. It was a spatial structure made up of the right arch, the invert arch, the chord, etc., and was designed to bear bilateral loads. To research the cyclic behavior of the new double-arch structure, a scale-model cyclic test was conducted. First, the test setup and test method were presented in detail, and according to the test results, the cyclic behavior and failure characteristics of this structure were discussed. Then by analyzing the test cyclic envelope curve, it was found the curve was divided into three stages: the elastic stage, the local plastic stage and the failure stage at the local yield point and structural yield point. The gate model has local yield strength and structural yield strength, with both their values being bigger than that of the designing load. Therefore, the gate is safe enough for the projects. At last, dynamic property of the gate was analyzed considering additional mass of the water. It was found that the tidal bore shock would not cause resonance vibration of the gate.

  5. Three-dimensional measurement of foot arch in preschool children

    Directory of Open Access Journals (Sweden)

    Chang Hsun-Wen

    2012-09-01

    Full Text Available Abstract Background The prevalence of flexible flatfoot is high among preschool-aged children, but the effects of treatment are inconclusive due to the unclear definitions of normal flatfoot. To date, a universally accepted evaluation method of the foot arch in children has not been completely established. Our aims of this study were to establish a new method to evaluate the foot arch from a three dimensional perspective and to investigate the flexibility of the foot arch among children aged from two to six. Methods A total of 44 children aged from two to six years of age were put into five age groups in this study. The navicular height was measured with one leg standing, and both feet were scanned separately in both sitting and one leg standing positions to compute the foot arch volume. The arch volume index, which represents the ratio of the difference in volume between sitting and one leg standing positions to the volume when sitting was calculated to demonstrate the flexibility of the foot arch. The differences of measured parameters between each aged group were analyzed by one-way ANOVA. Results The arch volumes when sitting and standing were highly correlated with the navicular height. The navicular height ranged from 15.75 to 27 mm, the arch volume when sitting ranged from 6,223 to 11,630 mm3, and the arch volume when standing from 3,111 to 7,848 mm3 from two to six years of age. The arch volume index showed a declining trend as age increased. Conclusion This study is the first to describe the foot arch with volume perspective in preschool-aged children. The foot arch volume was highly correlated with the navicular height. Research results show both navicular height index and arch volume index gradually increase with age from two to six. At the same time the arch also becomes rigid with age from two to six. These results could be applied for clinical evaluation of the foot arch and post-treatment evaluation.

  6. Spontaneous regression of intracranial aneurysm following remote ruptured aneurysm treatment with pipeline stent assisted coiling.

    Science.gov (United States)

    Tsimpas, Asterios; Ashley, William W; Germanwala, Anand V

    2016-10-01

    Spontaneous aneurysm regression is a rare phenomenon. We present the interesting case of a 54-year-old woman who was admitted with a Hunt/Hess grade IV, Fisher grade III subarachnoid hemorrhage and multiple intracranial aneurysms. She was treated with coiling of the largest paraclinoid aneurysm and placement of a flow diverting pipeline embolization device that covered all internal carotid artery (ICA) aneurysms. A follow-up angiogram at 6 months showed remodeling of the ICA with complete obliteration of all treated aneurysms. A distant, untreated, right frontal M2 aneurysm regressed spontaneously, after the flow was diverted away from it with the stent. The literature is reviewed, and potential pathophysiological mechanisms leading to aneurysm regression are discussed.

  7. Accuracy and reproducibility of patient-specific hemodynamic models of stented intracranial aneurysms: report on the Virtual Intracranial Stenting Challenge 2011.

    Science.gov (United States)

    Cito, S; Geers, A J; Arroyo, M P; Palero, V R; Pallarés, J; Vernet, A; Blasco, J; San Román, L; Fu, W; Qiao, A; Janiga, G; Miura, Y; Ohta, M; Mendina, M; Usera, G; Frangi, A F

    2015-01-01

    Validation studies are prerequisites for computational fluid dynamics (CFD) simulations to be accepted as part of clinical decision-making. This paper reports on the 2011 edition of the Virtual Intracranial Stenting Challenge. The challenge aimed to assess the reproducibility with which research groups can simulate the velocity field in an intracranial aneurysm, both untreated and treated with five different configurations of high-porosity stents. Particle imaging velocimetry (PIV) measurements were obtained to validate the untreated velocity field. Six participants, totaling three CFD solvers, were provided with surface meshes of the vascular geometry and the deployed stent geometries, and flow rate boundary conditions for all inlets and outlets. As output, they were invited to submit an abstract to the 8th International Interdisciplinary Cerebrovascular Symposium 2011 (ICS'11), outlining their methods and giving their interpretation of the performance of each stent configuration. After the challenge, all CFD solutions were collected and analyzed. To quantitatively analyze the data, we calculated the root-mean-square error (RMSE) over uniformly distributed nodes on a plane slicing the main flow jet along its axis and normalized it with the maximum velocity on the slice of the untreated case (NRMSE). Good agreement was found between CFD and PIV with a NRMSE of 7.28%. Excellent agreement was found between CFD solutions, both untreated and treated. The maximum difference between any two groups (along a line perpendicular to the main flow jet) was 4.0 mm/s, i.e. 4.1% of the maximum velocity of the untreated case, and the average NRMSE was 0.47% (range 0.28-1.03%). In conclusion, given geometry and flow rates, research groups can accurately simulate the velocity field inside an intracranial aneurysm-as assessed by comparison with in vitro measurements-and find excellent agreement on the hemodynamic effect of different stent configurations.

  8. Including Functional Annotations and Extending the Collection of Structural Classifications of Protein Loops (ArchDB

    Directory of Open Access Journals (Sweden)

    Antoni Hermoso

    2007-01-01

    Full Text Available Loops represent an important part of protein structures. The study of loop is critical for two main reasons: First, loops are often involved in protein function, stability and folding. Second, despite improvements in experimental and computational structure prediction methods, modeling the conformation of loops remains problematic. Here, we present a structural classification of loops, ArchDB, a mine of information with application in both mentioned fields: loop structure prediction and function prediction. ArchDB (http://sbi.imim.es/archdb is a database of classified protein loop motifs. The current database provides four different classification sets tailored for different purposes. ArchDB-40, a loop classification derived from SCOP40, well suited for modeling common loop motifs. Since features relevant to loop structure or function can be more easily determined on well-populated clusters, we have developed ArchDB-95, a loop classification derived from SCOP95. This new classification set shows a ∼40% increase in the number of subclasses, and a large 7-fold increase in the number of putative structure/function-related subclasses. We also present ArchDB-EC, a classification of loop motifs from enzymes, and ArchDB-KI, a manually annotated classification of loop motifs from kinases. Information about ligand contacts and PDB sites has been included in all classification sets. Improvements in our classification scheme are described, as well as several new database features, such as the ability to query by conserved annotations, sequence similarity, or uploading 3D coordinates of a protein. The lengths of classified loops range between 0 and 36 residues long. ArchDB offers an exhaustive sampling of loop structures. Functional information about loops and links with related biological databases are also provided. All this information and the possibility to browse/query the database through a web-server outline an useful tool with application in the

  9. Idiopathic giant right atrial aneurysm

    Directory of Open Access Journals (Sweden)

    Santosh C Uppu

    2013-01-01

    Full Text Available A 2-year-old boy with an incidental finding of massive cardiomegaly on a chest X-ray was diagnosed with a giant right atrial aneurysm upon further investigation with echocardiography. The patient underwent successful surgical reduction of the right atrium and closure of the patent foramen ovale to prevent thromboembolic complications and to lower the risk of atrial arrhythmias. The resected atrium had paper-thin walls and pathological features of interstitial fibrosis with endocardial thickening.

  10. The Evolution of Protoplanetary Discs in the Arches Cluster

    CERN Document Server

    Olczak, C; Harfst, S; Pfalzner, S; Zwart, S Portegies

    2012-01-01

    Most stars form in a cluster environment. These stars are initially surrounded by discs from which potentially planetary systems form. Of all cluster environments starburst clusters are probably the most hostile for planetary systems in our Galaxy. The intense stellar radiation and extreme density favour rapid destruction of circumstellar discs via photoevaporation and stellar encounters. Evolving a virialized model of the Arches cluster in the Galactic tidal field we investigate the effect of stellar encounters on circumstellar discs in a prototypical starburst cluster. Despite its proximity to the deep gravitational potential of the Galactic centre only a moderate fraction of members escapes to form an extended pair of tidal tails. Our simulations show that encounters destroy one third of the circumstellar discs in the cluster core within the first 2.5 Myr of evolution, preferentially affecting the least and most massive stars. A small fraction of these events causes rapid ejection and the formation of a we...

  11. Double aortic arch and nasogastric tubes: A fatal combination

    Institute of Scientific and Technical Information of China (English)

    Julia Massaad; Kelly Crawford

    2008-01-01

    Double aortic arch is a common form of complete vascular ring that encircles both the trachea and the esophagus, and presents with various respiratory and esophageal symptoms, usually in the pediatric population.We present a case of double aortic arch in an adult patient that manifested as massive upper gastrointestinal bleeding after prolonged nasogastric intubation.

  12. Defect in Posterior Arch of Atlas in Myelomeningocele

    NARCIS (Netherlands)

    G. Blaauw (Gerhard)

    1971-01-01

    textabstractThe posterior arches of the cervical vertebrae of 30 children who died with a myelomeningocele in the lower thoracic, lumbar or sacral region were examined; in 70 per cent of these cases a defect was found in the posterior arch of the atlas, which was bridged by a firm fibrous band. Alté

  13. Twin - Arch technique. Revival of the "edgewise -Technique"?

    Directory of Open Access Journals (Sweden)

    Jacob Karp

    2012-01-01

    The SNB – Bracket brings a new dimension into the orthodontic world which is most apparent in extraction cases. Its Teflon – like material has a very low friction coefficient thus, reducing the treatment time considerably. Through the use of low dimensioned arch wires, the Twin – Arch Technique becomes a Light – wire system and simultaneously provides good anchorage and torque control.

  14. Adult presentation with vascular ring due to double aortic arch.

    Science.gov (United States)

    Kafka, Henryk; Uebing, Anselm; Mohiaddin, Raad

    2006-11-01

    This is a case report on the use of cardiovascular magnetic resonance imaging to diagnose vascular ring due to double aortic arch in an adult presenting with an abnormal chest X-ray. The experience in this case and the literature review identify the benefits of using cardiovascular magnetic resonance imaging to clarify complex aortic arch anatomy.

  15. Full-scale load tests of Pearl-Chain arches

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

    2017-01-01

    , pre-fabricated, composite, lightweight, concrete deck elements (SL-Decks), that are post-tensioned together into an arch shape. The two Pearl-Chain arches, each with a span of 13m and a rise of 1m, were placed on a post tensioned bearing plate prepared in advance. The aches are tested with load...

  16. Computational Study of Intracranial Aneurysms with Flow Diverting Stent: Correlation with Surgical Outcome

    Science.gov (United States)

    Tang, Yik Sau; Chiu, Tin Lok; Tsang, Anderson Chun On; Leung, Gilberto Ka Kit; Chow, Kwok Wing

    2016-11-01

    Intracranial aneurysm, abnormal swelling of the cerebral artery, can cause massive internal bleeding in the subarachnoid space upon aneurysm rupture, leading to a high mortality rate. Deployment of a flow diverting stent through endovascular technique can obstruct the blood flow into the aneurysm, thus reducing the risk of rupture. Patient-specific models with both bifurcation and sidewall aneurysms have been investigated. Computational fluid dynamics analysis with physiological boundary conditions has been performed. Several hemodynamic parameters including volume flow rate into the aneurysm and the energy (sum of the fluid kinetic and potential energy) loss between the inlet and outlets were analyzed and compared with the surgical outcome. Based on the simulation results, we conjecture that a clinically successful case might imply less blood flow into the aneurysm after stenting, and thus a smaller amount of energy loss in driving the fluid flow in that portion of artery. This study might provide physicians with quantitative information for surgical decision making. (Partial financial support by the Innovation and Technology Support Program (ITS/011/13 & ITS/150/15) of the Hong Kong Special Administrative Region Government)

  17. Optimum coil insertion speed of various coils in brain aneurysm embolization in vitro.

    Science.gov (United States)

    Konishi, Yoshifumi; Takeuchi, Masataka; Fukasaku, Kazuaki

    2016-10-01

    A coil must comprise material with shape memory to perform optimal coil embolization. To achieve this, the alloy characteristics of the coil (hardness, shape, and thickness) must be understood. In this experiment, a catheter was fixed in the bright position and the movement of the coil was observed under a constant rate of insertion; the optimal insertion rate during clinical use was investigated. The first coil insertion speed was evaluated using simulated aneurysms in an in vivo arterial model. The results showed that the insertion force relates to the deployment shape of the coil, that the feedback through the force indicator using sound is very effective, and that the recorder is useful for analysis of coil embolization. The inserted coils during aneurysm embolization were able to wind uniformly within the aneurysm due to a variety of factors (guiding or micro-catheter position and kick-back phenomenon such as delivery wire). Optimal speed is achieved with proper coil design, which allows the coil to be inserted into the aneurysm. The shape and size of the aneurysm can help determine the necessary size and design of the coil that should be used during the optimal speed range. Aneurysm wall and coil characteristics are considered, along with the friction state of the coil (hardness, shape, and thickness), leading to improvements in safety during the insertion procedure at optimum speed.

  18. Wall shear stress and pressure distribution on aneurysms and infundibulae in the posterior communicating artery bifurcation.

    Science.gov (United States)

    Baek, Hyoungsu; Jayaraman, Mahesh V; Karniadakis, George Em

    2009-12-01

    A growing number of cases of rupture at an infundibulum, progression of infundibulum to a frank aneurysm, and subarachnoid hemorrhage (SAH) in the posterior communicating artery (PCoA) have been reported. Using patient-specific geometric models of the supraclinoid internal carotid artery (ICA) with PCoA infundibulum or aneurysm, high-resolution computational fluid dynamics simulations were performed by solving the Navier-Stokes equations with a spectral/hp element method. Simulation results show that the flow impinges at the distal wall of infundibulum near the outside of the ICA bend and creates a region of higher pressure (4-5 mmHg) surrounded by a band of a high wall shear stress (WSS) (20-30 N/m(2) on average). At the proximal end of the infundibulum, another stagnation area is formed characterized by low WSS (shear index. This impingement region seems to coincide with the locations of the rupture of infundibulae or progression to aneurysms. In addition, the pulsatile flow becomes unstable due to the presence of aneurysms or aneurysm-like infundibulae, and this leads to WSS temporal fluctuations inside the aneurysm, which may accelerate the degenerative processes in the vessel walls.

  19. Controlled release of osteopontin and interleukin-10 from modified endovascular coil promote cerebral aneurysm healing.

    Science.gov (United States)

    Chen, Jingyi; Yang, Lijun; Chen, Yan; Zhang, Gengshen; Fan, Zheneng

    2016-01-15

    Cerebral aneurysm is a bulging of the artery inside the brain that results from a weakened or thin area of the artery wall. Ruptured cerebral aneurysm could lead to serious brain damage or even death, thus the proper treatment is essential. Compared with the conventional microsurgical clipping approach, the endovascular coiling treatment has many advantages, however, with a major disadvantage of high recurrence rate. One way to lower the recurrence rate, which has been tried since one decade ago, is to modify the coil to be bioactive and releasing biological molecules to stimulate tissue ingrowth and aneurysm healing. We have identified three candidates including osteopontin (OPN), IL-10 and matrix metallopeptidase 9 (MMP-9) from previous studies and generated platinum coils coated with these proteins in the carrier of poly-DL-lactic glycolic acid (PLGA). We were interested to know whether coils coated with OPN, IL-10 and MMP-9 were able to promote aneurysm healing and we have tested it in the rat carotid aneurysm model. We found that OPN and IL-10 coated coils had shown significant improvement in tissue ingrowth while MMP-9 coated coils failed to enhance tissue ingrowth compared with the control group. Our studies suggested the possible application of OPN and IL-10 coated coils in aneurysm treatment to overcome the recurrence.

  20. Shared Genetic Risk Factors of Intracranial, Abdominal, and Thoracic Aneurysms

    NARCIS (Netherlands)

    van 't Hof, Femke N G; Ruigrok, Ynte M; Lee, Cue Hyunkyu; Ripke, Stephan; Anderson, Graig; de Andrade, Mariza; Baas, Annette F; Blankensteijn, Jan D; Böttinger, Erwin P; Bown, Matthew J; Broderick, Joseph; Bijlenga, Philippe; Carrell, David S; Crawford, Dana C; Crosslin, David R; Ebeling, Christian; Eriksson, Johan G; Fornage, Myriam; Foroud, Tatiana; von Und Zu Fraunberg, Mikael; Friedrich, Christoph M; Gaál, Emília I; Gottesman, Omri; Guo, Dong-Chuan; Harrison, Seamus C; Hernesniemi, Juha; Hofman, Albert; Inoue, Ituro; Jääskeläinen, Juha E; Jones, Gregory T; Kiemeney, Lambertus A L M; Kivisaari, Riku; Ko, Nerissa; Koskinen, Seppo; Kubo, Michiaki; Kullo, Iftikhar J; Kuivaniemi, Helena; Kurki, Mitja I; Laakso, Aki; Lai, Dongbing; Leal, Suzanne M; Lehto, Hanna; LeMaire, Scott A; Low, Siew-Kee; Malinowski, Jennifer; McCarty, Catherine A; Milewicz, Dianna M; Mosley, Thomas H; Nakamura, Yusuke; Nakaoka, Hirofumi; Niemelä, Mika; Pacheco, Jennifer; Peissig, Peggy L; Pera, Joanna; Rasmussen-Torvik, Laura; Ritchie, Marylyn D; Rivadeneira, Fernando; van Rij, Andre M; Santos-Cortez, Regie Lyn P; Saratzis, Athanasios; Slowik, Agnieszka; Takahashi, Atsushi; Tromp, Gerard; Uitterlinden, André G; Verma, Shefali S; Vermeulen, Sita H; Wang, Gao T; Han, Buhm; Rinkel, Gabriël J E; de Bakker, Paul I W

    2016-01-01

    BACKGROUND: Intracranial aneurysms (IAs), abdominal aortic aneurysms (AAAs), and thoracic aortic aneurysms (TAAs) all have a familial predisposition. Given that aneurysm types are known to co-occur, we hypothesized that there may be shared genetic risk factors for IAs, AAAs, and TAAs. METHODS AND RE

  1. Familial Abdominal Aortic Aneurysm : Clinical Features and Genetics

    NARCIS (Netherlands)

    K.M. van de Luijtgaarden (Koen)

    2016-01-01

    markdownabstractAbstract Cardiovascular disease is the most important cause of death in the world and encompasses occlusive as well as aneurysmal disease. The most common aneurysm in humans is the abdominal aortic aneurysm (AAA). The question is why the aorta dilates in aneurysmal disease and occ

  2. Seismic multi-arch structures in East China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In previous papers (Wencai, 2002, 2003), the author has analyzed the deep seismic reflection profiles along some of the Mesozoic plutons in East China, and has pointed out that the crustal structures around these intrusions usually correlate with a special seismic fabric called the seismic multi-arch structure. This paper will continue to show main characteristics of the seismic multi-arch structures and discuss their relationship with mantle-origin magmatism and the lithospheric thinning process. Calibration of seismic reflectors in Chinese continental drilling sites shows that small-scale arch-like reflectors can be generated by fractured eclogites or other plutons, they do not belong to the multi-arch structure specially discussed in the paper. The multi-arch structure is characterized by several arch-like reflectors distributed in both the upper and lower crust with granitoid plutons or stocks exposed on the surface, which do not have obvious negative Europium anomalies. Based on the distribution pattern of arch reflectors, the multi-arch magmatic structures can be divided into three main types, namely the simple vertical combination type, the spread arch magmatic structure and the arch-bouquet structure. All of them correlate to mantle-origin magmatism, but occur in different places. The spread arch magmatic structures occur within a Mesozoic/Cenozoic rift zone with very thin and hot lithosphere. The vertical combination type of the multi-arch structures occurred near the rift zones where lithosphere was thin and hot. The arch-bouquet magmatic structures occur far from the rift zones where the lithosphere is not hot. The continental rifting acted as the late episode of the lithospheric thinning process seeing that the rift zones usually coincide with the thinnest parts of the lithosphere in East China. In different locations within the lithospheric thinning areas, mantle-origin magmatic activities have different characteristics, which might generate different

  3. Atlantoaxial stabilization using multiaxial C-1 posterior arch screws.

    Science.gov (United States)

    Donnellan, Michael B; Sergides, Ioannis G; Sears, William R

    2008-12-01

    The authors present a novel technique of atlantoaxial fixation using multiaxial C-1 posterior arch screws. The technique involves the insertion of bilateral multiaxial C-1 posterior arch screws, which are connected by crosslinked rods to bilateral multiaxial C-2 pars screws. The clinical results are presented in 3 patients in whom anomalies of the vertebral arteries, C-1 lateral masses, and/or posterior arch of C-1 presented difficulty using existing fixation techniques with transarticular screws, C-1 lateral mass screws, or posterior wiring. The C-1 posterior arch screws achieved solid fixation and their insertion appeared to be technically less demanding than that of transarticular or C-1 lateral mass screws. This technique may reduce the risk of complications compared with existing techniques, especially in patients with anatomical variants of the vertebral artery, C-1 lateral masses, or C-1 posterior arch. This technique may prove to be an attractive fixation option in patients with normal anatomy.

  4. Left testicular artery arching over the ipsilateral renal vein

    Institute of Scientific and Technical Information of China (English)

    Munekazu Naito; Hayato Terayama; Yoichi Nakamura; Shogo Hayashi; Takayoshi Miyaki; Masahiro Itoh

    2006-01-01

    Aim: To report two cases of the left testicular artery arching over the left renal vein (LRV) before running downward to the testis. Methods: The subjects were obtained from two Japanese cadavers. During the student course of gross-anatomical dissection, the anatomical relationship between the testicular vessels and the renal vein was specifically observed. Results: The arching left testicular artery arose from the aorta below the LRV and made a loop around the LRV, which appeared to be mildly compressed between the arching artery and the psoas major muscle.Conclusion: Clinically, compression of the LRV between the abdominal aorta and the superior mesenteric artery occasionally induces LRV hypertension, resulting in varicocele, orthostatic protenuria and hematuria. Considering that the incidence of a left arching testicular artery is higher than that of a right one, an arching left artery could be an additional cause of LRV hypertension.

  5. Effect of Obesity on Arch Index in Young Adults

    Directory of Open Access Journals (Sweden)

    Sneha Sameer Ganu

    2013-01-01

    Full Text Available Background: Excessive increases in weight bearing forces caused by obesity may negatively affect the lower limbs and feet but minimal research has examined the long-term loading effects of obesity on the musculoskeletal system, particularly in reference to the feet. Objectives: The purpose of the study was to investigate the effect of obesity on medial longitudinal arch of foot in young adults. Method: 60 subjects, 30 obese & 30 non obese were assessed for height & weight using standard technique. Radiographic images under static condition were used for calculating the arch index. Result: The arch index of obese subjects was significantly lower than the non obese subjects & there is a negative correlation between the BMI & the arch index. Conclusion: These results suggests that obesity lowers the medial longitudinal arch of foot.

  6. Multimodal optical measurement in vitro of surface deformations and wall thickness of the pressurized aortic arch.

    Science.gov (United States)

    Genovese, Katia; Humphrey, Jay D

    2015-04-01

    Computational modeling of arterial mechanics continues to progress, even to the point of allowing the study of complex regions such as the aortic arch. Nevertheless, most prior studies assign homogeneous and isotropic material properties and constant wall thickness even when implementing patient-specific luminal geometries obtained from medical imaging. These assumptions are not due to computational limitations, but rather to the lack of spatially dense sets of experimental data that describe regional variations in mechanical properties and wall thickness in such complex arterial regions. In this work, we addressed technical challenges associated with in vitro measurement of overall geometry, full-field surface deformations, and regional wall thickness of the porcine aortic arch in its native anatomical configuration. Specifically, we combined two digital image correlation-based approaches, standard and panoramic, to track surface geometry and finite deformations during pressurization, with a 360-deg fringe projection system to contour the outer and inner geometry. The latter provided, for the first time, information on heterogeneous distributions of wall thickness of the arch and associated branches in the unloaded state. Results showed that mechanical responses vary significantly with orientation and location (e.g., less extensible in the circumferential direction and with increasing distance from the heart) and that the arch exhibits a nearly linear increase in pressure-induced strain up to 40%, consistent with other findings on proximal porcine aortas. Thickness measurements revealed strong regional differences, thus emphasizing the need to include nonuniform thicknesses in theoretical and computational studies of complex arterial geometries.

  7. Optimization design of foundation excavation for Xiluodu super-high arch dam in China

    Institute of Scientific and Technical Information of China (English)

    Qixiang Fan; Shaowu Zhou; Ning Yang

    2015-01-01

    With better understanding of the quality and physico-mechanical properties of rocks of dam foundation, and the physico-mechanical properties and structure design of arch dam in association with the foun-dation excavation of Xiluodu arch dam, the excavation optimization design was proposed for the foundation surface on the basis of feasibility study. Common analysis and numerical analysis results demonstrated the feasibility of using the weakly weathered rocks III1 and III2 as the foundation surface of super-high arch dam. In view of changes in the geological conditions at the dam foundation along the riverbed direction, the design of extending foundation surface excavation area and using consolidating grouting and optimizing structure of dam bottom was introduced, allowing for harmonization of the arch dam and foundation. Three-dimensional (3D) geomechanics model test and finite element analysis re-sults indicated that the dam body and foundation have good overload stability and high bearing capacity. The monitoring data showed that the behaviors of dam and foundation correspond with the designed patterns in the construction period and the initial operation period.

  8. Optimization design of foundation excavation for Xiluodu super-high arch dam in China

    Directory of Open Access Journals (Sweden)

    Qixiang Fan

    2015-04-01

    Full Text Available With better understanding of the quality and physico-mechanical properties of rocks of dam foundation, and the physico-mechanical properties and structure design of arch dam in association with the foundation excavation of Xiluodu arch dam, the excavation optimization design was proposed for the foundation surface on the basis of feasibility study. Common analysis and numerical analysis results demonstrated the feasibility of using the weakly weathered rocks III1 and III2 as the foundation surface of super-high arch dam. In view of changes in the geological conditions at the dam foundation along the riverbed direction, the design of extending foundation surface excavation area and using consolidating grouting and optimizing structure of dam bottom was introduced, allowing for harmonization of the arch dam and foundation. Three-dimensional (3D geomechanics model test and finite element analysis results indicated that the dam body and foundation have good overload stability and high bearing capacity. The monitoring data showed that the behaviors of dam and foundation correspond with the designed patterns in the construction period and the initial operation period.

  9. Aneurysms of medium-sized arteries in Marfan syndrome.

    Science.gov (United States)

    Awais, Mazen; Williams, David M; Deeb, G Michael; Shea, Michael J

    2013-11-01

    Marfan syndrome is a relatively common connective tissue disorder that causes skin, ocular, skeletal, and cardiovascular abnormalities. High morbidity and mortality occur with aortic aneurysm and dissection. Other large-artery aneurysms, including carotid, subclavian, and iliac artery aneurysms, have also been associated with Marfan syndrome. It is not clear whether small- to medium-sized artery aneurysms are associated with Marfan syndrome. This report describes 4 patients with Marfan syndrome who have associated small- to medium-sized artery aneurysms with several complications. Additional investigations are needed to determine whether Marfan syndrome can cause small- to medium-sized artery aneurysms and how patients with these aneurysms should be treated.

  10. Growth rates of intracranial aneurysms : exploring constancy

    NARCIS (Netherlands)

    Koffijberg, Hendrik; Buskens, Erik; Algra, Ale; Wermer, Marieke J. H.; Rinkel, Gabriel J. E.

    2008-01-01

    Object. The annual rate of rupture of intracranial aneurysms is often assumed to be constant, but it is unknown whether this assumption is true. Recent case reports have suggested that aneurysms grow fast in a short period of time. The authors of the present report investigated the plausibility of a

  11. [Gigantic aneurysm of the popliteal artery].

    Science.gov (United States)

    Fernández-Samos, R; Zorita, A; Vázquez, J G; Morán, C; Vaquero, F

    1990-01-01

    A giant popliteal aneurysm case, whose first symptom was an acute ischemia on the limb, caused by thrombosis, which was successfully treated, is reported. Although popliteal aneurysm is not a rare event, the interest of this case is focused on its extraordinary size and unique location.

  12. Migraine before rupture of intracranial aneurysms

    DEFF Research Database (Denmark)

    Lebedeva, Elena R; Gurary, Natalia M; Sakovich, Vladimir P

    2013-01-01

    Rupture of a saccular intracranial aneurysm (SIA) causes thunderclap headache but it remains unclear whether headache in general and migraine in particular are more prevalent in patients with unruptured SIA.......Rupture of a saccular intracranial aneurysm (SIA) causes thunderclap headache but it remains unclear whether headache in general and migraine in particular are more prevalent in patients with unruptured SIA....

  13. Aneurysm of the Right Atrial Appendage

    Directory of Open Access Journals (Sweden)

    Silvio Henrique Barberato

    2002-02-01

    Full Text Available Atrial aneurysms involving the free wall or atrial appendage are rare entities in cardiology practice and may be associated with atrial arrhythmias or embolic phenomena. We review the literature and report a case of aneurysm of the right atrial appendage in a young adult, whose diagnosis was established with echocardiography after an episode of paroxysmal atrial flutter.

  14. The role of inflammation in cerebral aneurysms

    Directory of Open Access Journals (Sweden)

    Ali H Turkmani

    2015-06-01

    Full Text Available The natural history of unruptured intracranial aneurysms (IAs is poorly understood. At present, risk factors for aneurysm rupture are limited to demographics and rudimentary anatomic features of the aneurysm. The first sign of aneurysm destabilization and rupture may be subarachnoid hemorrhage, a potentially devastating brain injury with high morbidity and mortality. An emerging body of literature suggests a complex inflammatory cascade likely promotes aneurysm wall remodeling and progressive ballooning of the arterial wall, ultimately terminating in aneurysm rupture. These events likely begin with hemodynamic, flow-related endothelial injury; the injured endothelium stimulates inflammation, including the recruitment and transmigration of inflammatory cells, particularly macrophages. Various proteases are secreted by the inflammatory infiltrate, resulting in degradation of the extracellular matrix and the structural changes unique to IAs. Detailed understanding of these inflammatory processes may result in (1 early identification of patients at high risk for aneurysm rupture, perhaps via arterial wall imaging, and (2 targeted, noninvasive therapies to treat or even prevent cerebral aneurysms.

  15. Simultaneous presentation of two cerebral aneurysms.

    Science.gov (United States)

    Yoshida, Masahiro; Ezura, Masayuki; Sasaki, Kazuto; Chonan, Masashi; Mino, Masaki

    2012-01-01

    A 48-year-old woman experienced sudden onset of severe headache. Computed tomography showed subarachnoid hemorrhage (SAH) and intracerebral hematoma in the right frontal lobe. Digital subtraction angiography revealed three aneurysms in the anterior communicating artery (AcomA), the right posterior communicating artery (PcomA), and the right middle cerebral artery. The AcomA aneurysm was treated with endovascular coiling. However, her oculomotor nerve palsy was aggravated after the procedure. Embolization of the right PcomA aneurysm was conducted immediately and her oculomotor nerve palsy recovered completely 3 months later. Simultaneous presentation of multiple aneurysms with separate symptoms is rare. We speculate that the progressive oculomotor nerve palsy was caused by tiny enlargement or morphological change of the aneurysm caused by elevated blood pressure and pulsatile effect after SAH.

  16. Head positioning for anterior circulation aneurysms microsurgery

    Directory of Open Access Journals (Sweden)

    Feres Chaddad-Neto

    2014-11-01

    Full Text Available Objective To study the ideal patient's head positioning for the anterior circulation aneurysms microsurgery. Method We divided the study in two parts. Firstly, 10 fresh cadaveric heads were positioned and dissected in order to ideally expose the anterior circulation aneurysm sites. Afterwards, 110 patients were submitted to anterior circulation aneurysms microsurgery. During the surgery, the patient's head was positioned accordingly to the aneurysm location and the results from the cadaveric study. The effectiveness of the position was noted. Results We could determine mainly two patterns for head positioning for the anterior circulation aneurysms. Conclusion The best surgical exposure is related to specific head positions. The proper angle of microscopic view may minimize neurovascular injury and brain retraction.

  17. Advances in the imaging of cerebral aneurysm inflammation

    Directory of Open Access Journals (Sweden)

    Michael R Levitt

    2015-06-01

    Full Text Available Cerebral aneurysm formation, growth and rupture are thought to be the result of a complex interaction between cerebrovascular hemodynamics and pathobiology. Recently, new evidence has emerged regarding the role of inflammation in the walls of cerebral aneurysms. Noninvasive methods to characterize the degree of inflammation in aneurysms could enable clinicians to estimate the risk of future aneurysm growth and rupture, influencing treatment. This review examines emerging techniques of imaging inflammatory biomarkers in cerebral aneurysms.

  18. [Aneurysm of the anterior inferior cerebellar artery: case report].

    Science.gov (United States)

    Adorno, Juan Oscar Alarcón; de Andrade, Guilherme Cabral

    2002-12-01

    The intracranial aneurysms of the posterior circulation have been reported between 5 and 10% of all cerebral aneurysms and the aneurysms of the anterior inferior cerebellar artery (AICA) are considered rare, can cause cerebello pontine angle (CPA) syndrome with or without subarachnoid hemorrhage. Since 1948 few cases were described in the literature. We report on a 33 year-old female patient with subarachnoid hemorrhage due to sacular aneurysm of the left AICA. She was submitted to clipage of the aneurysm without complications.

  19. Model analysis of changes in dental arch width before and after orthodontic treatment with MBT appliance%MBT矫治前后牙弓宽度变化的模型分析研究

    Institute of Scientific and Technical Information of China (English)

    张良

    2012-01-01

    目的 分析牙列拥挤患者不拔牙与拔牙的MBT矫治对牙弓宽度变化的影响.方法 选择我院正畸科2008-2011年MBT矫治器治疗的牙列拥挤患者40例.其中轻中度牙列拥挤患者20例,使用MBT矫治器进行不拔牙正畸;中重度牙列拥挤患者20例,使用MBT矫治器进行拔除4颗第一前磨牙的拔牙正畸.测量术前术后石膏模型的牙弓宽度,对矫治前后不拔牙组和拔牙组的测量数据分别进行组内、组间统计学分析.结果 矫治前后不拔牙组:上颌尖牙间宽度增大,上下颌第一前磨牙、第一磨牙间宽度增大,有统计学意义;拔牙组:上颌尖牙间宽度增大,上下颌第二前磨牙、第一磨牙间宽度变小,有统计学意义.矫治前2组上下颌尖牙、第一磨牙间牙弓宽度相近,无统计学差异;矫治后不拔牙组上下颌第一磨牙间牙弓宽度大于拔牙组,有统计学意义,2组上下颌尖牙间牙弓宽度相近,差异无统计学意义.结论 不拔牙矫治牙弓宽度变化与拥挤部位、拥挤程度有关,拔牙矫治牙弓宽度变化主要与牙齿移动方向有关.拔牙矫治后尖牙间宽度不会减小.%Objective To investigate the changes of dental arch width after extraction and nonextraction treatment with MBT appliance. Methods 40 patients with crowded denture who received treatment with MBT appliance from 2008 to 2011 in our hospital were randomly selected. 20 patients with mild dental crowding who received nonextraction treatment were in the nonextraction group, while 20 patients with severe dental crowding whose 4 first premolars were extracted in the treatment with MBT appliance were in the extraction group. SPSS 11.0 software package was used for paired-samples t Test and independent-samples t Test. Results The upper inter-canine widths, the upper and lower inter-first bicuspid widths, the upper and lower inter-first molar widths of nonextraction cases increased significantly after the treatment. The

  20. Hemodynamic simulations in coronary aneurysms of children with Kawasaki disease

    Science.gov (United States)

    Sengupta, Dibyendu; Burns, Jane; Marsden, Alison

    2009-11-01

    Kawasaki disease (KD) is a serious pediatric illness affecting the cardiovascular system. One of the most serious complications of KD, occurring in about 25% of untreated cases, is the formation of large aneurysms in the coronary arteries, which put patients at risk for myocardial infarction. In this project we performed patient specific computational simulations of blood flow in aneurysmal left and right coronary arteries of a KD patient to gain an understanding about their hemodynamics. Models were constructed from CT data using custom software. Typical pulsatile flow waveforms were applied at the model inlets, while resistance and RCR lumped models were applied and compared at the outlets. Simulated pressure waveforms compared well with typical physiologic data. High wall shear stress values are found in the narrow region at the base of the aneurysm and low shear values occur in regions of recirculation. A Lagrangian approach has been adopted to perform particle tracking and compute particle residence time in the recirculation. Our long-term goal will be to develop links between hemodynamics and the risk for thrombus formation in order to assist in clinical decision-making.

  1. Subarachnoid hemorrhage with blister aneurysms: Endovascular management

    Directory of Open Access Journals (Sweden)

    Swati Dayanand Chinchure

    2014-01-01

    Full Text Available Blister aneurysms of are rare lesions representing a real challenge for diagnosis and management. They typically show small size, hemispherical shape, fragile wall, broad neck, and are arising from non-branching sites of intracranial arteries. Materials and Methods: We retrospectively reviewed all aneurysms treated at our institution. Seventeen patients (6 male, 11 female with 17 blister aneurysms were identified (mean age 53.3, range 41-63 years. Clinical, procedural, angiographic data as well as follow up data were evaluated. Results: All patients presented with aneurysmal subarachnoid hemorrhage. Majority of the blister aneurysms were located in ICA while 1 was located at posterior cerebral artery, 1 at vertebral and 1 involving basilar artery. All patients were treated using single or overlapping stents and if possible additional coiling. There was no intra-operative rupture. Good outcome (mrs 0-2 was seen in 14 patients. Poor clinical outcome (mrs 3-5 was seen in 2 patients due to vasospasm induced ischemic deficits at discharge, both of them improved on follow up (mrs 1 on follow up. There were 3 mortalities, One patient died of rebleeding while other 2 died due to SAH induced complications. Follow-up angiography was available in 16 patients (one patient died before follow up angiogram and revealed complete or near complete aneurysm occlusion in 11, incomplete obliteration in 1 and no change in 2 cases. Two cases showed post-treatment angiographic aneurysm recurrence. Both cases were managed with repeat coiling and overlapping stent placement. Conclusion: Endovascular management using single/overlapping stent and if possible coil placement is technically safe and feasible in blister aneurysms. Overlapping stents lead to better aneurysm occlusion than a single stent. Blister aneurysm in dorso-medial ICA showed higher tendency of continued growth/recurrence, higher incidence of clinical vasospasm and in these cases early angiographic follow

  2. Clinical trial of doxycycline for matrix metalloproteinase-9 inhibition in patients with an abdominal aneurysm doxycycline selectively depletes aortic wall neutrophils and cytotoxic t cells

    NARCIS (Netherlands)

    Lindeman, J.H.N.; Abdul-Hussien, H.; Bockel, J.H. van; Wolterbeek, R.; Kleemann, R.

    2009-01-01

    Background-Doxycycline has been shown to effectively inhibit aneurysm formation in animal models of abdominal aortic aneurysm. Although this effect is ascribed to matrix metalloproteinase-9 inhibition, such an effect is unclear in human studies. We reevaluated the effect of doxycycline on aortic wal

  3. Using COMSOL Multiphysics for Biomechanical Analysis of Stent Technology in Cerebral Aneurysms

    DEFF Research Database (Denmark)

    Rasmussen, Joachim; Thyregod, Jesper; Enevoldsen, Marie Sand;

    2009-01-01

    This work presents new fluid-structure interaction (FSI) models in both 2D and 3D of the effect of using vascular stents as treatment of cerebral berry aneurysms. The stent is positioned inside the cerebral artery covering the neck of the aneurysm. The stent is expected to alter the blood flow in...... and strut size, shape, and position are modeled in 2D and 3D FSI models. The models show that pore size and strut shape both have significant influence on stent efficiency....

  4. Transforming growth factor-β and abdominal aortic aneurysms.

    Science.gov (United States)

    Wang, Yutang; Krishna, Smriti; Walker, Philip J; Norman, Paul; Golledge, Jonathan

    2013-01-01

    Abdominal aortic aneurysms (AAAs) are common problems in aged people which can be associated with severe complications including aortic rupture and death. Transforming growth factor-β (TGFβ) has been implicated as causative in the development of thoracic aortic aneurysms (TAAs). In contrast, current evidence suggests TGFβ inhibits AAA development. Polymorphisms in the TGFβ signaling components are associated with AAA in some human population studies. In experimental animals TGFβ protects against AAA formation, progression and rupture. In animal models of AAA TGFβ decreases aortic inflammatory cell infiltration, extracellular matrix degradation, and vascular smooth muscle cell apoptosis, all factors implicated in AAA pathogenesis. The TGFβ signaling pathway may provide a therapeutic target for AAA although better clarity is needed regarding the distinct roles of TGFβ in TAA and AAA.

  5. Longitudinal force in continuously welded rail on long-span tied arch continuous bridge carrying multiple tracks

    Institute of Scientific and Technical Information of China (English)

    YAN Bin; DAI Gong-lian; GUO Wen-hua; XU Qing-yuan

    2015-01-01

    Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete composite section beam element to simulate concrete-filled steel tube (CFST) arch rib, using the beam element with rigid arm to simulate the prestressed concrete girder and using nonlinear bar element to simulate longitudinal constraint between track and bridge. Taking a (77+3×156.8+77) m tied arch continuous bridge with four tracks on the Harbin-Qiqihar Passenger Dedicated Line as an example, the arrangement of continuously welded rail (CWR) was explored. The longitudinal force in CWR on the tied arch continuous bridge, the pier top horizontal force and torque due to the unbalance load case, were analyzed under the action of temperature, vertical live load, train braking and wind load. Studies show that, it can significantly reduce track displacement to set the track expansion devices at main span arch springing on both sides; the track stress due to arch temperature variation can reach 40.8 MPa; the track stress, pier top horizontal force and torque are related to the number of loaded tracks and train running direction, and the bending force applied to unloaded track is close to the loaded track, while the braking force applied to unloaded track is 1/4 to 1/2 of the loaded track; the longitudinal force of track due to the wind load is up to 12.4 MPa, which should be considered.

  6. In-vivo quantification of wall motion in cerebral aneurysms from 2D cine phase contrast magnetic resonance images

    Energy Technology Data Exchange (ETDEWEB)

    Karmonik, C. [The Methodist Hospital Research Inst., Houston (United States); Diaz, O.; Klucznik, R. [The Methodist Hospital, Houston (United States); Grossman, R. [The Methodist Hospital, Houston (United States). Neurosurgery

    2010-02-15

    Purpose: The quantification of wall motion in cerebral aneurysms is of interest for the assessment of aneurysmal rupture risk, for providing boundary conditions for computational simulations and as a validation tool for theoretical models. Materials and Methods: 2D cine phase contrast magnetic resonance imaging (2D pcMRI) in combination with quantitative magnetic resonance angiography (QMRA) was evaluated for measuring wall motion in 7 intracranial aneurysms. In each aneurysm, 2 (in one case 3) cross sections, oriented approximately perpendicular to each other, were measured. Results: The maximum aneurysmal wall distention ranged from 0.16 mm to 1.6 mm (mean 0.67 mm), the maximum aneurysmal wall contraction was -1.91 mm to -0.34 mm (mean 0.94 mm), and the average wall displacement ranged from 0.04 mm to 0.31 mm (mean 0.15 mm). Statistically significant correlations between average wall displacement and the shape of inflow curves (p-value < 0.05) were found in 7 of 15 cross sections; statistically significant correlations between the displacement of the luminal boundary center point and the shape of inflow curves (p-value < 0.05) were found in 6 of 15 cross sections. Conclusion: 2D pcMRI in combination with QMRA is capable of visualizing and quantifying wall motion in cerebral aneurysms. However, application of this technique is currently restricted by its limited spatial resolution. (orig.)

  7. Computational study for the effects of coil configuration on blood flow characteristics in coil-embolized cerebral aneurysm.

    Science.gov (United States)

    Otani, Tomohiro; Ii, Satoshi; Shigematsu, Tomoyoshi; Fujinaka, Toshiyuki; Hirata, Masayuki; Ozaki, Tomohiko; Wada, Shigeo

    2016-07-21

    Coil embolization of cerebral aneurysms with inhomogeneous coil distribution leads to an incomplete occlusion of the aneurysm. However, the effects of this factor on the blood flow characteristics are still not fully understood. This study investigates the effects of coil configuration on the blood flow characteristics in a coil-embolized aneurysm using computational fluid dynamics (CFD) simulation. The blood flow analysis in the aneurysm with coil embolization was performed using a coil deployment (CD) model, in which the coil configuration was constructed using a physics-based simulation of the CD. In the CFD results, total flow momentum and kinetic energy in the aneurysm gradually decayed with increasing coil packing density (PD), regardless of the coil configuration attributed to deployment conditions. However, the total shear rate in the aneurysm was relatively high and the strength of the local shear flow varied based on the differences in coil configuration, even at adequate PDs used in clinical practice (20-25 %). Because the sufficient shear rate reduction is a well-known factor in the blood clot formation occluding the aneurysm inside, the present study gives useful insight into the effects of coil configuration on the treatment efficiency of coil embolization.

  8. New Insight into the Toughening Mechanisms of Seashell: From Arch Shape to Multilayer Structure

    Directory of Open Access Journals (Sweden)

    Quan Yuan

    2016-01-01

    Full Text Available A seashell is a closed three-dimensional curved surface formed by two symmetrical open shells. Three-point bending is performed on a pure aragonite straight beam (PASB model and a multilayer structure curved beam (MSCB model to elucidate the structure-property relationships of seashells. The integrity of the PASB is broken because of the introduction of a soft layer, but this drawback is compensated by the peculiar arch shape and the internal multilayer structure. The effective modulus, stiffness, and fracture energy of MSCB increase with an increase in volume fraction, aspect ratio of aragonite platelet, overlap ratio of hard layers, and ratio of the elastic modulus of the hard layer to the shear modulus of the soft layer. New design disciplines drawn from the MSCB model are peculiar arch shape, internal multilayer structure of larger volume fraction, and aspect ratio of hard layers and nanoscaled soft layers.

  9. Theoretical and Experimental Investigation of the Nonlinear Behavior of an Electrostatically Actuated In-Plane MEMS Arch

    KAUST Repository

    Ramini, Abdallah

    2016-05-02

    We present theoretical and experimental investigation of the nonlinear behavior of a clamped-clamped in-plane MEMS arch when excited by a DC electrostatic load superimposed to an AC harmonic load. Experimentally, a case study of in-plane silicon micromachined arch is examined and its mechanical behavior is measured using optical techniques. An algorithm is developed to extract the various parameters, such as the induced axial force and the initial rise, needed to model the behavior of the arch. A softening spring behavior is observed when the excitation is close to the first resonance frequency due to the quadratic nonlinearity coming from the arch geometry and the electrostatic force. Also, a hardening spring behavior is observed when the excitation is close to the third (second symmetric) resonance frequency due to the cubic nonlinearity coming from mid-plane stretching. Dynamic snap-through behavior is also reported for larger range of electric loads. Theoretically, a multi-mode Galerkin reduced order model is utilized to simulate the arch behavior. General agreement is reported among the theoretical and experimental data.

  10. Evaluation of flow with dynamic x-ray imaging for aneurysms

    Science.gov (United States)

    Dohatcu, Andreea Cristina

    The main goal of this thesis is to evaluate blood flow inside cerebrovascular aneurysms using dynamic x-ray imaging. X-ray contrast substance (dye) was auto injected in elastomer aneurysm models placed in a flow loop (for in-vitro studies) to trace flow passing through aneurysms. More specifically, an improved Time-Density Curves (TDC) Roentgen-videodensitometric tracking technique, that included looking to designated regions (R) within an aneurysm rather than focusing on the entire aneurysm, was employed to get information about blood flow using cine-angiographic sequences. It is the first time R-TDC technique has been used. In complex real-time interventions on patients, 2D/3D angiographic analysis of contrast media flow is the only reliable and rapid source of information that we have in order to assess the seriousness of the disease, suggest the treatment, and verify the result of the treatment. The present study focused on finding a "correlation metric" to quantitatively describe the flow behavior within the aneurysms and examine the hemodynamic implications of several treatments using flow modulating devices applied to saccular and bifurcation geometries aneurysms. The main idea in treatment of an aneurysm is rapid reduction of the risk of rupture. This is usually done endovascularly now by totally occluding the aneurysm by packing it with mechanical or chemical agents. Our research, however, involves a new method of blocking the neck using various types of asymmetric vascular stents (AVS). We proposed and analyzed, using R-TDCs, the feasibility of a new modified endovascular method of treatment based on alteration of blood flow through the aneurysm by partial occlusion only. In-vitro studies using aneurysm phantoms with patient-specific aneurysm models were performed. Also, for the first time the new methods were used in in-vivo studies as well, on rabbit-model experimental data, in an attempt to correlate thrombogenic response of a living organism to flow

  11. Electronic database of arterial aneurysms

    Directory of Open Access Journals (Sweden)

    Fabiano Luiz Erzinger

    2014-12-01

    Full Text Available Background:The creation of an electronic database facilitates the storage of information, as well as streamlines the exchange of data, making easier the exchange of knowledge for future research.Objective:To construct an electronic database containing comprehensive and up-to-date clinical and surgical data on the most common arterial aneurysms, to help advance scientific research.Methods:The most important specialist textbooks and articles found in journals and on internet databases were reviewed in order to define the basic structure of the protocol. Data were computerized using the SINPE© system for integrated electronic protocols and tested in a pilot study.Results:The data entered onto the system was first used to create a Master protocol, organized into a structure of top-level directories covering a large proportion of the content on vascular diseases as follows: patient history; physical examination; supplementary tests and examinations; diagnosis; treatment; and clinical course. By selecting items from the Master protocol, Specific protocols were then created for the 22 arterial sites most often involved by aneurysms. The program provides a method for collection of data on patients including clinical characteristics (patient history and physical examination, supplementary tests and examinations, treatments received and follow-up care after treatment. Any information of interest on these patients that is contained in the protocol can then be used to query the database and select data for studies.Conclusions:It proved possible to construct a database of clinical and surgical data on the arterial aneurysms of greatest interest and, by adapting the data to specific software, the database was integrated into the SINPE© system, thereby providing a standardized method for collection of data on these patients and tools for retrieving this information in an organized manner for use in scientific studies.

  12. Complications of endovascular treatment of cerebral aneurysms.

    Science.gov (United States)

    Orrù, Emanuele; Roccatagliata, Luca; Cester, Giacomo; Causin, Francesco; Castellan, Lucio

    2013-10-01

    The number of neuroendovascular treatments of both ruptured and unruptured aneurysms has increased substantially in the last two decades. Complications of endovascular treatments of cerebral aneurysms are rare but can potentially lead to acute worsening of the neurological status, to new neurological deficits or death. Some of the possible complications, such as vascular access site complications or systemic side effects associated with contrast medium (e.g. contrast medium allergy, contrast induced nephropathy) can also be encountered in diagnostic angiography. The most common complications of endovascular treatment of cerebral aneurysms are related to acute thromboembolic events and perforation of the aneurysm. Overall, the reported rate of thromboembolic complications ranges between 4.7% and 12.5% while the rate of intraprocedural rupture of cerebral aneurysms is about 0.7% in patients with unruptured aneurysms and about 4.1% in patients with previously ruptured aneurysms. Thromboembolic and hemorrhagic complications may occur during different phases of endovascular procedures and are related to different technical, clinical and anatomic reasons. A thorough knowledge of the different aspects of these complications can reduce the risk of their occurrence and minimize their clinical sequelae. A deep understanding of complications and of their management is thus part of the best standard of care.

  13. Complications of endovascular treatment of cerebral aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Orrù, Emanuele, E-mail: surgeon.ema@gmail.com [Neuroradiology Department, Padua University Hospital, Via Giustiniani 2, Padua 35128 (Italy); Roccatagliata, Luca, E-mail: lroccatagliata@neurologia.unige.it [Neuroradiology Department, IRCCS San Martino University Hospital and IST, Largo Rosanna Benzi 10, Genoa 16132 (Italy); Department of Health Sciences (DISSAL), University of Genoa (Italy); Cester, Giacomo, E-mail: giacomo.cester@sanita.padova.it [Neuroradiology Department, Padua University Hospital, Via Giustiniani 2, Padua 35128 (Italy); Causin, Francesco, E-mail: francesco.causin@sanita.padova.it [Neuroradiology Department, Padua University Hospital, Via Giustiniani 2, Padua 35128 (Italy); Castellan, Lucio, E-mail: lucio.castellan@hsanmartino.it [Neuroradiology Department, IRCCS San Martino University Hospital and IST, Largo Rosanna Benzi 10, Genoa 16132 (Italy)

    2013-10-01

    The number of neuroendovascular treatments of both ruptured and unruptured aneurysms has increased substantially in the last two decades. Complications of endovascular treatments of cerebral aneurysms are rare but can potentially lead to acute worsening of the neurological status, to new neurological deficits or death. Some of the possible complications, such as vascular access site complications or systemic side effects associated with contrast medium (e.g. contrast medium allergy, contrast induced nephropathy) can also be encountered in diagnostic angiography. The most common complications of endovascular treatment of cerebral aneurysms are related to acute thromboembolic events and perforation of the aneurysm. Overall, the reported rate of thromboembolic complications ranges between 4.7% and 12.5% while the rate of intraprocedural rupture of cerebral aneurysms is about 0.7% in patients with unruptured aneurysms and about 4.1% in patients with previously ruptured aneurysms. Thromboembolic and hemorrhagic complications may occur during different phases of endovascular procedures and are related to different technical, clinical and anatomic reasons. A thorough knowledge of the different aspects of these complications can reduce the risk of their occurrence and minimize their clinical sequelae. A deep understanding of complications and of their management is thus part of the best standard of care.

  14. Insights on a Giant Aneurysm Treated Endovascularly.

    Science.gov (United States)

    Graziano, Francesca; Iacopino, Domenico Gerardo; Ulm, Arthur John

    2016-07-01

    Background Endovascular treatment with stent-assisted Guglielmi detachable coils is an accepted method for treating intracranial giant aneurysms that otherwise would require more invasive or destructive treatment or could not be treated at all. Nevertheless, there is a paucity of information concerning inner postcoiling aneurysmal changes in human subjects over the long term. We report a postmortem analysis of a patient with a giant aneurysm at the vertebrobasilar junction (VBJ) who was treated endovascularly and studied pathologically 24 months after treatment. Materials and Method The head was removed at autopsy and prefixed in a 10% neutral buffered formalin solution. The brain was gently removed from the skull base after cutting the intracranial nerves and vascular structures. The giant VBJ aneurysm and its relationship with the brainstem, cranial nerves, and vessels were captured photographically and analyzed. Afterward, under operating microscope guidance, the vertebrobasilar system with the aneurysm was gently and carefully detached from the brainstem and carefully analyzed. Results No complete fibrous obliteration of the aneurysm lumen could be detected in our case, and no endothelialization had taken place 24 months after treatment. Conclusions Our findings agree with those of previous similar reports. Coiling, in particular in large or giant aneurysms, may be burdened by the risk of coil compaction and recanalization, but it has the advantage of not affecting the flow in the perforating arteries.

  15. Intracranial aneurysm growth quantification in CTA

    Science.gov (United States)

    Firouzian, Azadeh; Manniesing, Rashindra; Metz, Coert T.; Klein, Stefan; Velthuis, Birgitta K.; Rinkel, Gabriel J. E.; van der Lugt, Aad; Niessen, Wiro J.

    2012-02-01

    Next to aneurysm size, aneurysm growth over time is an important indicator for aneurysm rupture risk. Manual assessment of aneurysm growth is a cumbersome procedure, prone to inter-observer and intra-observer variability. In clinical practice, mainly qualitative assessment and/or diameter measurement are routinely performed. In this paper a semi-automated method for quantifying aneurysm volume growth over time in CTA data is presented. The method treats a series of longitudinal images as a 4D dataset. Using a 4D groupwise non-rigid registration method, deformations with respect to the baseline scan are determined. Combined with 3D aneurysm segmentation in the baseline scan, volume change is assessed using the deformation field at the aneurysm wall. For ten patients, the results of the method are compared with reports from expert clinicians, showing that the quantitative results of the method are in line with the assessment in the radiology reports. The method is also compared to an alternative method in which the volume is segmented in each 3D scan individually, showing that the 4D groupwise registration method agrees better with manual assessment.

  16. CFD and PIV analysis of hemodynamics in a growing intracranial aneurysm.

    Science.gov (United States)

    Raschi, Marcelo; Mut, Fernando; Byrne, Greg; Putman, Christopher M; Tateshima, Satoshi; Viñuela, Fernando; Tanoue, Tetsuya; Tanishita, Kazuo; Cebral, Juan R

    2012-02-01

    Hemodynamics is thought to be a fundamental factor in the formation, progression, and rupture of cerebral aneurysms. Understanding these mechanisms is important to improve their rupture risk assessment and treatment. In this study, we analyze the blood flow field in a growing cerebral aneurysm using experimental particle image velocimetry (PIV) and computational fluid dynamics (CFD) techniques. Patient-specific models were constructed from longitudinal 3D computed tomography angiography images acquired at 1-y intervals. Physical silicone models were constructed from the computed tomography angiography images using rapid prototyping techniques, and pulsatile flow fields were measured with PIV. Corresponding CFD models were created and run under matching flow conditions. Both flow fields were aligned, interpolated, and compared qualitatively by inspection and quantitatively by defining similarity measures between the PIV and CFD vector fields. Results showed that both flow fields were in good agreement. Specifically, both techniques provided consistent representations of the main intra-aneurysmal flow structures and their change during the geometric evolution of the aneurysm. Despite differences observed mainly in the near wall region, and the inherent limitations of each technique, the information derived is consistent and can be used to study the role of hemodynamics in the natural history of intracranial aneurysms.

  17. The assessment of crowding without the need to record arch perimeter. Part I: Arches with acceptable alignment.

    Science.gov (United States)

    Battagel, J M

    1996-05-01

    A simplified, mathematically determined technique for calculating arch perimeter (the overlap method) is described and its validity in determining an accurate assessment of crowding is tested. Indices, expressed in millimetres of crowding or spacing, were computed for both the whole arch and the labial segment alone. Study casts of 36 individuals with clinically acceptable lower arches were used to validate the method. The degree of crowding or spacing calculated was compared with a "clinical' assessment of each arch, in which the irregularity was measured directly using a steel ruler. Various calculation schemes were tested. Depending on exactly how the overlap was determined, the results varied slightly. Although the arches showed acceptable alignment, it was preferable to include a strategy for normalizing the positions of any rotated teeth before the overlaps were calculated. Repositioning any bucco-lingually displaced teeth into the line of the arch, however, was not useful. For the complete arch good agreement with the clinical assessment was reached on 31 occasions and for the labial segment, all but one appraisals were within 0.5 mm of each other. In the remaining instances (five complete arches and one labial segment), the degree of crowding or spacing was between 0.5 and 1 mm of the clinical assessment. Considering that clinical measurement of minor degrees of crowding and spacing cannot be precise, these results were considered acceptable. The method was easy to use, relying only on the recording of mesio-distal tooth widths and was acceptably reproducible. The technique would therefore appear to provide a valid yet simple research tool with which to record the degree of crowding. Its ability to cope with irregular and crowded arches will be the subject of a subsequent review.

  18. A comparative study of inter-abutment distance of dies made from full arch dual-arch impression trays with those made from full arch stock trays: An in vitro study

    Directory of Open Access Journals (Sweden)

    Reddy Jagan

    2009-01-01

    Full Text Available Objectives: The dual-arch impression technique is convenient in that it makes the required maxillary and mandibular impressions, as well as the inter-occlusal record in one procedure. The accuracy of inter-abutment distance in dies fabricated from dual-arch impression technique remains in question because there is little information available in the literature. Materials and Methods: This study was conducted to evaluate the accuracy of inter-abutment distance in dies obtained from full arch dual-arch trays with those obtained from full arch stock metal trays. Results and Conclusion: The metal dual-arch trays showed better accuracy followed by the plastic dual-arch and stock dentulous trays, respectively, though statistically insignificant. The pouring sequence did not have any effect on the inter-abutment distance statistically, though pouring the non-working side of the dual-arch impression first showed better accuracy.

  19. Is there any association between facial type and mandibular dental arch form in subjects with normal occlusion?

    Directory of Open Access Journals (Sweden)

    Luiz Renato Paranhos

    2014-03-01

    The aim of this study was investigate the association between the mandibular arch morphology and the facial type of Brazilian Caucasians with natural normal occlusion. For this, we used a sample comprised of lateral radiographs and respective dental casts of 51 individuals (21 male and 30 female, presenting at least 4 of the 6 Andrews’ keys to normal occlusion without previous orthodontic treatment. Angle’s first molar relationship was considered indispensable for the sample. The facial type was defined by two cephalometric measurements (SN.SGn and SN.GoGn. After scanning the models (3D and radiographs, the images were evaluated by 12 orthodontists. A modified Kappa test evaluated the agreement between examiners to classify the morphology of the dental arch. The chi-square test was used to verify the association between the facial type (dolichofacial, mesofacial, or brachyfacial and the dental arch morphology (square, oval, or tapered, using significance level of 5%. Casual and systematic errors (p > 0.05 showed no significant results and the Kappa test showed significant agreement among examiners for the dental arch form (0.55 with a p < 0.001, considered as ‘moderate’. The chi-square test indicated no significant association. The null hypothesis was accepted, as the facial type was not associated with dental arch morphology in individuals with normal occlusion.

  20. A case of neonatal arterial thrombosis mimicking interrupted aortic arch.

    Science.gov (United States)

    Gürsu, Hazım Alper; Varan, Birgül; Oktay, Ayla; Özkan, Murat

    2015-06-01

    Neonatal arterial thrombosis is a very rare entity with clinical findings resembling coarctation of aorta or interrupted aortic arch. A two day-old male newborn was admitted to a different hospital with difficulty in sucking and sleepiness. On echocardiographic examination, a diagnosis of interrupted aortic arch was made and he was treated with prostoglandin E2. When the patient presented to our center, physical examination revealed that his feet were bilaterally cold. The pulses were not palpable and there were ecchymotic regions in the lower extremities. Echocardiography ruled out interrupted aortic arch. Computerized tomographic angiography revealed a large thrombosis and total occlusion of the abdominal aorta. Since there was no response to treatment with tissue plasminogen activator, we performed thrombectomy. Homozygous Factor V Leiden and Methylenetetrahydrofolate reductase mutations were found in this patient. Neonatal aortic thrombosis which is observed very rarely and fatal should be considered in the differential diagnosis of coarctation of aorta and interrupted aortic arch.

  1. PATIENT-SPECIFIC BLOOD DYNAMIC SIMULATIONS IN ASSESSING ENDOVASCULAR OCCLUSION OF INTRACRANIAL ANEURYSMS

    Institute of Scientific and Technical Information of China (English)

    CHEN Jia-liang; WANG Sheng-zhang; DING Guang-hong; YANG Xin-jian; LI Hai-yun

    2009-01-01

    According to recent studies, there are various potential predictors for surgical outcome for cerebral aneurysms. An accurate surgical outcome assessment would help make better-informed decisions and avoid the risk of rebleeding. It is well known that hemodynamic factors play an important role in the pathogenesis and treatment of intracranial aneurysms. In this article, a computational fluid dynamic analysis is applied to one patient-specific model of the cerebral aneurysm located at the tip of basilar artery, by which the differences of hemodynamic parameters before and after endovascular treatment may be evaluated. Based on the model, we show that the flow behavior near the neck of the aneurysm sees great differences after endovascular treatment as compared with that before treatment, which also affects the wall shear stress and the displacement distribution. In addition, our whole simulation process is based on a series of CFD commercial software packages, which are easily available for doctors to implement such a method in their daily practice. These results would be used to assess the outcome of endovascular treatment for the aneurysm occlusion.

  2. Computational lfuid dynamics simulation of intracranial aneurysms - comparing size and shape

    Institute of Scientific and Technical Information of China (English)

    Zifeng Yang; Hongtao Yu; George P Huang; Ryan Schwieterman; Bryan Ludwig

    2015-01-01

    Objective:To study the hemodynamics of an anatomic internal carotid artery aneurysm derived from a patient-specific model and then manipulate into two phantom morphologies: one growing uniformly by size and the other changing shape unevenly. Methods: The computational model of the saccular, internal carotid artery, aneurysm was constructed from 3D rotational, digitally subtracted, catheter angiography images. Computational fluid dynamics simulations were performed under pulsatile cardiac flow conditions. Velocity vectors, streamlines, pressure, and wall shear stress (WSS) and its variance distributions were quantitatively visualized. Results: The maximum pressure andWSS from the time-averaged distribution on the inside saccular surface of the original case are 415.38 and 17.61 Pa. In contrast, the bi-lobed shape gives rise to higher peak values of pressure (461.00 Pa) andWSS (33.20 Pa) on the saccular dome. Conversely, the evenly enlarged aneurysm actually results in a slightly lower peak pressure (399.58 Pa) and drastically decreasedWSS (9.81 Pa). Conclusions:The current study indicates that the size of the aneurysm should not be the only determining factor for the rupture risk consideration, the irregularity of the aneurysm shape and the corresponding aberrant hemodynamics might be a more important factor to consider for risk assessment.

  3. Clarifying the anatomy of the fifth arch artery

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    Saurabh Kumar Gupta

    2016-01-01

    Full Text Available The artery allegedly forming in the fifth pharyngeal arch has increasingly been implicated as responsible for various vascular malformations in patients with congenitally malformed hearts. Observations from studies on developing embryos, however, have failed to provide support to substantiate several of these inferences such that the very existence of the fifth arch artery remains debatable. To the best of our knowledge, in only a solitary human embryo has a vascular channel been found that truly resembled the artery of the fifth arch. Despite the meager evidence to support its existence, the fifth arch artery has been invoked to explain the morphogenesis of double-barreled aorta, some unusual forms of aortopulmonary communications, and abnormalities of the brachiocephalic arteries. In most of these instances, the interpretations have proved fallible when examined in the light of existing knowledge of cardiac development. In our opinion, there are more plausible alternative explanations for the majority of these descriptions. Double-barreled aorta is more likely to result from retention of the recently identified dorsal collateral channels while abnormalities of brachiocephalic arteries are better explained on the basis of extensive remodeling of aortic arches during fetal development. Some examples of aortopulmonary communications, nonetheless, may well represent persistence of the developing artery of the fifth pharyngeal arch. We here present one such case - a patient with tetralogy of Fallot and pulmonary atresia, in whom the fifth arch artery provided a necessary communication between the ascending aorta and the pulmonary arteries. In this light, we discuss the features we consider to be essential before attaching the tag of "fifth arch artery" to a candidate vascular channel.

  4. Infectious or Noninfectious? Ruptured, Thrombosed Inflammatory Aortic Aneurysm with Spondylolysis

    Energy Technology Data Exchange (ETDEWEB)

    Stefanczyk, Ludomir; Elgalal, Marcin, E-mail: telgalal@yahoo.co.uk [Medical University of Lodz, Department of Radiology and Diagnostic Imaging (Poland); Papiewski, Andrzej [Medical University of Lodz, Department of Gastroenterological Surgery (Poland); Szubert, Wojciech [Medical University of Lodz, Department of Radiology and Diagnostic Imaging (Poland); Szopinski, Piotr [Institute of Hematology and Transfusion Medicine, Clinic of Vascular Surgery (Poland)

    2013-06-15

    Osteolysis of vertebrae due to inflammatory aortic aneurysm is rarely observed. However, it is estimated that up to 10 % of infectious aneurysms coexist with bone tissue destruction, most commonly the vertebrae. Inflammatory aneurysms with no identified infection factor, along with infiltration of adjacent muscle and in particular extensive destruction of bone tissue have rarely been described in the literature. A case of inflammatory aneurysm with posterior wall rupture and inflammatory infiltration of the iliopsoas muscle and spine, together with extensive vertebral body destruction, is presented. The aneurysm was successfully treated with endovascular aneurysm repair EVAR.

  5. Infected abdominal aortic aneurysm due to Morganella morganii: CT findings.

    Science.gov (United States)

    Kwon, Oh Young; Lee, Jong Seok; Choi, Han Sung; Hong, Hoon Pyo; Ko, Young Gwan

    2011-02-01

    An infected aortic aneurysm, or mycotic aneurysm, is a rare arterial dilatation due to destruction of the infected vessel wall. Common pathogens resulting in an infected aortic aneurysm are Salmonella and Clostridium species, as well as Staphylococcus aureus; Morganella morganii, on the other hand, is very rare. An infected abdominal aortic aneurysm has tendencies to grow rapidly and to rupture. The mortality rate is high in patients undergoing emergent surgical intervention. We report the case of a 65-year-old man who presented with an infected abdominal aortic aneurysm caused by M. morganii. A high index of suspicion and imaging tests are necessary in order to diagnose an infected aortic aneurysm.

  6. Bilateral giant femoropopliteal artery aneurysms: a case report

    Directory of Open Access Journals (Sweden)

    Perdikides Theodossios P

    2008-04-01

    Full Text Available Abstract Introduction Popliteal artery aneurysms are the most common peripheral arterial aneurysms, and are frequently bilateral. Acute limb ischemia, rupture and compression phenomena can complicate these aneurysms when the diameter exceeds 2 cm. Case Presentation We report an 82-year-old male patient with two giant femoropopliteal aneurysms, 10.5 and 8.5 cm diameters, managed in our institution. Both aneurysms were resected and a polytetrafluoroethylene (PTFE femoropopliteal interposition graft was placed successfully. Management and literature review are discussed. Conclusion We believe this is the first report in the medical literature of bilateral giant femoropopliteal aneurysms.

  7. Behaviour of Frictional Joints in Steel Arch Yielding Supports

    Science.gov (United States)

    Horyl, Petr; Šňupárek, Richard; Maršálek, Pavel

    2014-10-01

    The loading capacity and ability of steel arch supports to accept deformations from the surrounding rock mass is influenced significantly by the function of the connections and in particular, the tightening of the bolts. This contribution deals with computer modelling of the yielding bolt connections for different torques to determine the load-bearing capacity of the connections. Another parameter that affects the loading capacity significantly is the value of the friction coefficient of the contacts between the elements of the joints. The authors investigated both the behaviour and conditions of the individual parts for three values of tightening moment and the relation between the value of screw tightening and load-bearing capacity of the connections for different friction coefficients. ANSYS software and the finite element method were used for the computer modelling. The solution is nonlinear because of the bi-linear material properties of steel and the large deformations. The geometry of the computer model was created from designs of all four parts of the structure. The calculation also defines the weakest part of the joint's structure based on stress analysis. The load was divided into two loading steps: the pre-tensioning of connecting bolts and the deformation loading corresponding to 50-mm slip of one support. The full Newton-Raphson method was chosen for the solution. The calculations were carried out on a computer at the Supercomputing Centre VSB-Technical University of Ostrava.

  8. Comparison of arch forms between Turkish and North American

    Directory of Open Access Journals (Sweden)

    Ahmet A. Celebi

    2016-04-01

    Full Text Available ABSTRACT Objective: The aim of this study was to clarify the morphological differences in the mandibular arches of Turkish and North American white subjects. Methods: The sample included 132 Turkish (34 Class I, 58 Class II, and 40 Class III and 160 North American (60 Class I, 50 Class II, and 50 Class III subjects. The most facial portion of 13 proximal contact areas was digitized from photocopied images of patients' mandibular dental arches. Clinical bracket points were calculated for each tooth based on mandibular tooth thickness data. Four linear and two proportional measurements were taken. The subjects were grouped according to arch form types (tapered, ovoid and square in order to have frequency distribution compared between ethnic groups in each Angle classification. Results: The Turkish group showed significantly lower molar depth and more significant molar width-depth (W/D ratio in all three Angle classifications. On the other hand, the Turkish group also showed a significantly larger intercanine width in Class III malocclusion and intermolar width in Class II malocclusion. The most frequent arch forms seen were the ovoid arch form in the Turkish group and the tapered form in the white group. Conclusions: Our results demonstrate that when treating Turkish patients, one should expect to use preformed ovoid arch form orthodontic wires in a significant percentage of patients.

  9. Comparison of arch forms between Turkish and North American

    Science.gov (United States)

    Celebi, Ahmet A.; Keklik, Hakan; Tan, Enes; Ucar, Faruk I.

    2016-01-01

    ABSTRACT Objective: The aim of this study was to clarify the morphological differences in the mandibular arches of Turkish and North American white subjects. Methods: The sample included 132 Turkish (34 Class I, 58 Class II, and 40 Class III) and 160 North American (60 Class I, 50 Class II, and 50 Class III) subjects. The most facial portion of 13 proximal contact areas was digitized from photocopied images of patients' mandibular dental arches. Clinical bracket points were calculated for each tooth based on mandibular tooth thickness data. Four linear and two proportional measurements were taken. The subjects were grouped according to arch form types (tapered, ovoid and square) in order to have frequency distribution compared between ethnic groups in each Angle classification. Results: The Turkish group showed significantly lower molar depth and more significant molar width-depth (W/D) ratio in all three Angle classifications. On the other hand, the Turkish group also showed a significantly larger intercanine width in Class III malocclusion and intermolar width in Class II malocclusion. The most frequent arch forms seen were the ovoid arch form in the Turkish group and the tapered form in the white group. Conclusions: Our results demonstrate that when treating Turkish patients, one should expect to use preformed ovoid arch form orthodontic wires in a significant percentage of patients. PMID:27275615

  10. CT Virtual angioscopy of aortic arch%CT仿真血管内镜观察主动脉弓

    Institute of Scientific and Technical Information of China (English)

    李新平; 陈伟; 朱智明

    2011-01-01

    [ Objective ] To explore the clinical value of CT virtual angioscopy (CTVA) in the pre- and postpro-cedure evaluation of aortic arch related diseases. [Methods] 37 cases with thoracic disease underwent aortic CT angiography on a dual-source CT scanner. CTVA of aortic arch were performed with Fly-through software in all cas-? Es by using aortic CT angiographic source image data. [Results] 34 of 37 (92%) cases showed successful CTVA images, including aortic dissection (n =12), aneurysm (n =4), pseudoaneurysm (n =3), Takayasu arteritis (n =2),aortic coarctation (n =1), aneurysm combined with aortic dissection (n =1) and 11 patients following surgical or endovascu-lar procedures. CTVA of aortic arch could identify the ostia and its variations of supra-aortic vessels, estimate the localization of abnormalities with respect to supra-aortic vessels and display the stent grafts. [ Conclusions ] CTVA of aortic arch enables non-invasive visualization of the inner contours of the vasculature, and has certain instructive significance in the diagnostic classification, preprocedure planning and postprocedure evaluation for aortic arch related diseases.%目的 探讨CT仿真血管内镜(CTVA)在主动脉弓相关疾病术前和术后评价中的价值.方法 采用双源CT对37例胸主动脉疾病患者行主动脉CT成像检查,并将主动脉CT成像的源图像调至Fly-through软件中,对所有病例行主动脉弓CTVA观察.结果 92%(34/37)的病例获得了满意的CTVA图像,包括主动脉夹层12例、真性动脉瘤4例、假性动脉瘤3例、多发性大动脉炎2例、主动脉缩窄1例、真性动脉瘤合并夹层1例及11例术后随访病例.主动脉弓CTVA能明确弓上分支血管开口位置与变异、判断病变与弓上分支开口的空间关系以及显示支架型血管.结论 主动脉弓CTVA能无创观察血管腔内情况,对主动脉弓相关疾病的诊断分型、术前计划和术后评价具有一定的指导意义.

  11. Microcatheter looping to facilitate aneurysm selection in coil embolization of paraclinoid aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Dae; Rhim, Jong Kook; Park, Jeong Jin; Jeon, Jin Sue; Yoo, Roh Eul; Kang, Hyun Seung; Kim, Jeong Eun; Cho, Won Sang; Han, Moon Hee [Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2015-08-15

    Described herein is a microcatheter looping technique to facilitate aneurysm selection in paraclinoid aneurysms, which remains to be technically challenging due to the inherent complexity of regional anatomy. This retrospective study was approved by our Institutional Review Board, and informed consent was waived. Microcatheter looping method was employed in 59 patients with paraclinoid aneurysms between January 2012 and December 2013. In the described technique, construction of a microcatheter loop, which is steam-shaped or pre-shaped, based on the direction of aneurysms, is mandatory. The looped tip of microcatheter was advanced into distal internal carotid artery and positioned atop the target aneurysm. By steering the loop (via inner microguidewire) into the dome of aneurysm and easing tension on the microcatheter, the aneurysm was selected. Clinical and morphologic outcomes were assessed with emphasis on technical aspects of the treatment. Through this looping technique, a total of 59 paraclinoid aneurysms were successfully treated. After aneurysm selection as described, single microcatheter technique (n = 25) was most commonly used to facilitate coiling, followed by balloon protection (n = 21), stent protection (n = 7), multiple microcatheters (n = 3), and stent/balloon combination (n = 3). Satisfactory aneurysmal occlusion was achieved through coil embolization in 44 lesions (74.6%). During follow-up of 53 patients (mean interval, 10.9 ± 5.9 months), only one instance (1.9%) of major recanalization was observed. There were no complications related to microcatheter looping. This microcatheter looping method facilitates safe and effective positioning of microcatheter into domes of paraclinoid aneurysms during coil embolization when other traditional microcatheter selection methods otherwise fail.

  12. "Microbleeding" from intracranial aneurysms: Local hemosiderin deposition identified during microsurgical treatment of unruptured intracranial aneurysms

    Directory of Open Access Journals (Sweden)

    Eric S Nussbaum

    2014-01-01

    Full Text Available Background: During elective surgery for unruptured aneurysms, we have identified a group of patients with hemosiderin staining of the pial surface immediately adjacent to the aneurysm dome suggesting a remote and unrecognized history of microbleeding from the aneurysm. These cases form the basis for this report. Methods: Medical records of 421 unruptured cerebral aneurysm patients treated surgically between January 2003 and September 2010 were retrospectively reviewed. Patients with a history of prior subarachnoid hemorrhage, craniotomy, or significant closed head injury were excluded from review. Records were reviewed for intraoperative descriptions of hemosiderin deposition in the vicinity of the aneurysm as well as history of headaches, time to presentation, comorbidities, aneurysm characteristics, procedures, and radiologic imaging. Results: Local hemosiderin staining immediately adjacent to the aneurysm was identified intraoperatively in 13 cases. Each of these patients had a history of remote atypical headache prior to presentation. Eight of these patients (62% had aneurysms described as particularly "thin-walled" at the time of surgery. Aneurysm locations included the internal carotid artery (ICA (54%, middle cerebral artery (MCA (23%, anterior communicating artery (ACOMMA (15%, and the anterior cerebral artery (ACA (8%. More than half (54% of these patients had a history of smoking, while 31% had hypertension, and 23% had a history of alcohol abuse. Dyslipidemia and family history of aneurysms were present in 15% and hypercholesterolemia was noted in one patient (8%. Conclusion: We suggest this group of patients had suffered a "microbleed" resulting in local hemosiderin deposition next to the aneurysm. The origins and clinical implications of such microbleeds are unknown and warrant further investigation.

  13. A meta-analysis of aneurysm formation in laser assisted vascular anastomosis (LAVA)

    Science.gov (United States)

    Chen, Chen; Peng, Fei; Xu, Dahai; Cheng, Qinghua

    2009-08-01

    Laser assisted vascular anastomosis (LAVA) is looked as a particularly promising non-suture method in future. However, aneurysm formation is one of the main reasons delay the clinical application of LAVA. Some scientists investigated the incidence of aneurysms in animal model. To systematically analyze the literature on reported incidence of aneurysm formation in LAVA therapy, we performed a meta-analysis comparing LAVA with conventional suture anastomosis (CSA) in animal model. Data were systematically retrieved and selected from PUBMED. In total, 23 studies were retrieved. 18 studies were excluded, and 5 studies involving 647 animals were included. Analysis suggested no statistically significant difference between LAVA and CSA (OR 1.24, 95%CI 0.66-2.32, P=0.51). Result of meta analysis shows that the technology of LAVA is very close to clinical application.

  14. [Inflammatory aneurysms of the abdominal aorta].

    Science.gov (United States)

    Tovar Martín, E; Acea Nebril, B

    1993-01-01

    Approximately 10 per cent of abdominal aneurysms have an excessively thick wall that sometimes involve duodenum, cava or colon by an inflammatory process. Between February 1986 and December 1992, 147 patients with abdominal aortic aneurysm (AAA) were treated surgically and in 13 (8.8%) the aneurysms were found to be inflammatory. Their mean age was 67.3 years (70.1 years in non inflammatory group) and all were symptomatics initially (abdominal pain in 53%, rupture in 23%, mass in 15%). The operative mortality for elective resection was 37% in patients with inflammatory abdominal aortic aneurysms (IAAA) decreasing to 9% in the AAA group without inflammatory involvement. We conclude that surgery is indicated in these patients to prevent rupture and to hasten the subsidense of inflammatory process ever with postoperative morbi-mortality increased.

  15. Dissecting aortic aneurysm in maintenance hemodialysis patients

    Directory of Open Access Journals (Sweden)

    Ounissi M

    2009-01-01

    Full Text Available The dissecting aortic aneurysm (DAA is a rare pathology that may result in fatal outcome. We report follow up of three cases of DAA patients undergoing maintenance hemo-dialysis who were managed conservatively.

  16. Ruptured venous aneurysm of cervicomedullary junction

    Directory of Open Access Journals (Sweden)

    Ashish Aggarwal

    2014-01-01

    Full Text Available Background: Ruptured venous aneurysm is often seen with arterio-venous malformation (AVM or developmental venous anomaly (DVA. However, isolated venous aneurysm is unusual. Case Description: We present a case of ruptured venous aneurysm that presented with subarachnoid hemorrhage (SAH and intraventricular hemorrhage (IVH. Digital substraction angiography (DSA revealed a saccular contrast filling pouch in the left lateral aspect of cervicomedullary junction (CMJ. Endovascular intervention was not a viable option. During surgery, a saccular pliable structure approx. 1.5 Χ 1 cm was found in the subarachnoid space that was clipped and excised. There were no arterial feeders, no evidence of surrounding AVM, and no dilated perimedullary vein. Conclusion: This is perhaps the first reported case of ruptured venous aneurysm (without associated AVM of CMJ, which was successfully managed surgically. The possible etiologies remain an unnoticed head trauma or a congenital vessel wall abnormality. Surgically clipping and excision remains the treatment of choice for such lesion.

  17. Hypopituitarism is uncommon after aneurysmal subarachnoid haemorrhage

    DEFF Research Database (Denmark)

    Klose, Marianne; Brennum, Jannick; Poulsgaard, Lars

    2010-01-01

    Aneurysmal subarachnoid haemorrhage (SAH) has recently been reported as a common cause of chronic hypopituitarism, and introduction of routine neuroendocrine screening has been advocated. We aimed at estimating the risk of hypopituitarism after SAH using strict criteria including confirmatory...

  18. External jugular venous aneurysm: A clinical curiosity

    Science.gov (United States)

    Mohanty, Debajyoti; Jain, Bhupendra Kumar; Garg, Pankaj Kumar; Tandon, Anupama

    2013-01-01

    Jugular venous aneurysm is an extremely rare condition. The patients presented with a painless swelling in the neck that appears while coughing, straining, bending, or breath holding. Detection of a soft and compressible swelling in the course of an external jugular vein (EJV) superficial to the sternomastoid muscle, non-filling on compression of the EJV during Valsalva maneuver clinches the diagnosis of EJV aneurysm. Color Doppler ultrasound allows precise delineation of the lesion and is considered the gold standard for confirming the diagnosis. Surgical excision is indicated mostly for cosmetic reasons and symptomatic aneurysms. We, herein, report a patient with saccular external jugular venous aneurysm to highlight the typical clinical presentation and diagnosis of this rare entity. PMID:23633867

  19. Natural history of abdominal aortic aneurysm

    DEFF Research Database (Denmark)

    Perko, M J; Schroeder, T V; Olsen, P S

    1993-01-01

    During a 10-year period in which 735 patients presented with abdominal aortic aneurysms to our clinic, 63 were not offered operative treatment. The primary reason for choosing conservative treatment was concomitant diseases that increased the risk of operation. After 2 years of followup, half...... of the patients died, and the cumulative 5-year survival rate was 15%. Aneurysm rupture was the primary cause of death. The cumulative 5-year mortality hazard rate from rupture was 0.36, corresponding to an annual risk of rupture of 7%. The cumulative 5-year hazard rate of death from all other causes was 1.......53, corresponding to an annual risk of 30%. Diameter of the aneurysm was found to be the only factor with a significant impact on the rate of rupture. The cumulative 5-year hazard rate of rupture among patients with aneurysms or = 6 cm was 0.2 and 0.6, respectively, corresponding to an annual risk...

  20. Aneurysmal portosystemic venous shunt: a case report.

    Science.gov (United States)

    Bodner, G; Glück, A; Springer, P; König, P; Perkmann, R

    1999-10-01

    A case of an aneurysmal portosystemic venous shunt detected by colour Doppler ultrasound (CDUS) is presented. A young female patient complained of postprandial fatigue and had paroxysmal tachycardia. A direct vascular communication between right portal vein and right hepatic vein was found at CDUS and confirmed by direct portal angiogram. Using detachable coils a complete occlusion of the intrahepatic shunt was obtained. Reports from the literature regarding portovenous aneurysms are reviewed.

  1. Multiple tuberculous aneurysms of the aorta.

    Science.gov (United States)

    Pierret, Charles; Tourtier, Jean-Pierre; Grand, Bertrand; Boddaert, Guillaume; Laurian, Claude; de Kerangal, Xavier

    2011-06-01

    Tuberculous aneurysms of the aorta are quite rare, but are exceptional when found in multiple locations. We report the case of multiple tuberculous aortic aneurysms of the thoracic and abdominal aorta in a 19-year-old female discovered when she consulted for thrombocytopenic purpura. The treatment for both locations included prolonged antituberculous therapy and surgical resection with cryopreserved aortic allograft patch for the reconstruction.

  2. Construction Simulation and Real-Time Control for High Arch Dam

    Institute of Scientific and Technical Information of China (English)

    ZHONG Denghua; REN Bingyu; WU Kangxin

    2008-01-01

    A method of combining dynamic simulation with real-time control was proposed to fit the randomness and uncertainty in the high arch dam construction process. The mathematical logic model of high arch dam construction process was established. By combining dynamic con-struction simulation with schedule analysis, the process of construction schedule forecasting and analysis based on dynamic simulation was studied. The process of real-time schedule control was constructed and some measures for dynamic adjustment and control of construction schedule were provided. A system developed with the method is utilized in a being constructed hydroelectric pro-ject located at the Yellow River in northwest China, which can make the pouring plan of the dam in the next stage (a month, cluarter or year) to guide the practical construction. The application result shows that the system provides an effective technical support for the construction and manage-ment of the dam.

  3. Microsimulations of Arching, Clogging, and Bursty Exit Phenomena in Crowd Dynamics

    CERN Document Server

    Castro, Francisco Enrique Vicente G

    2015-01-01

    We present in this paper the behavior of an artificial agent who is a member of a crowd. The behavior is based on the social comparison theory, as well as the trajectory mapping towards an agent's goal considering the agent's field of vision. The crowd of artificial agents were able to exhibit arching, clogging, and bursty exit rates. We were also able to observe a new phenomenon we called double arching, which happens towards the end of the simulation, and whose onset is exhibited by a "calm" density graph within the exit passage. The density graph is usually bursty at this area. Because of these exhibited phenomena, we can use these agents with high confidence to perform microsimulation studies for modeling the behavior of humans and objects in very realistic ways.

  4. Analysis of intracranial aneurysm wall motion and its effects on hemodynamic patterns

    Science.gov (United States)

    Oubel, Estanislao; De Craene, Mathieu; Putman, Christopher M.; Cebral, Juan R.; Frangi, Alejandro F.

    2007-03-01

    Hemodynamics, and in particular Wall Shear Stress (WSS), is thought to play a critical role in the progression and rupture of intracranial aneurysms. Wall motion is related to local biomechanical properties of the aneurysm, which in turn are associated with the amount of damage undergone by the tissue. The underlying hypothesis in this work is that injured regions show differential motion with respect to normal ones, allowing a connection between local wall biomechanics and a potential mechanism of wall injury such as elevated WSS. In a previous work, a novel method was presented combining wall motion estimation using image registration techniques with Computational Fluid Dynamics (CFD) simulations in order to provide realistic intra-aneurysmal flow patterns. It was shown that, when compared to compliant vessels, rigid models tend to overestimate WSS and produce smaller areas of elevated WSS and force concentration, being the observed differences related to the magnitude of the displacements. This work aims to further study the relationships between wall motion, flow patterns and risk of rupture in aneurysms. To this end, four studies containing both 3DRA and DSA studies were analyzed, and an improved version of the method developed previously was applied to cases showing wall motion. A quantification and analysis of the displacement fields and their relationships to flow patterns are presented. This relationship may play an important role in understanding interaction mechanisms between hemodynamics, wall biomechanics, and the effect on aneurysm evolution mechanisms.

  5. Intracranial aneurysms in an African country

    Directory of Open Access Journals (Sweden)

    Ogeng'o Julius

    2009-12-01

    Full Text Available Background : Characteristics of intracranial aneurysms display ethnic variations. Data on this disease from the African continent is scarce and often conflicting. Aim : To describe site, age and gender distribution of intracranial aneurysms among Kenyans. Study Design and Setting : Retrospective study at Kenyatta National Hospital, Kenya. Materials and Methods: All records of black African patients with a diagnosis of intracranial aneurysms seen at Kenyatta National Hospital, the largest referral hospital in the Eastern and Central African region, over the period from January 1998 to December 2007 were examined for site, age and gender distribution. The data gathered were coded, analyzed with SPSS 11.50. Results : Fifty-six cases of intracranial aneurysms were analyzed. The posterior communicating artery was the most affected (35.7%, followed by the anterior communicating artery (26.8%, while the posterior cerebral artery was the least affected (2%. Multiple aneurysms were present in 2%. The mean age at presentation was 50.9 years (range 21-80 years and the gender distribution was equal. Conclusions : Intracranial aneurysms among Kenyans occur most commonly on the posterior communicating artery, in young individuals, and without gender bias. The distribution differs from that described in the literature and this requires search for risk factors.

  6. Endovascular treatment for ruptured basilar apex aneurysm

    Directory of Open Access Journals (Sweden)

    Sheng LI

    2011-12-01

    Full Text Available Objective The present study aims to prove the effectiveness and safety of endovascular interventional therapy for ruptured basilar apex aneurysm.Methods The imaging data,methods of endovascular treatment,and clinical results of 12 patients suffering from ruptured basilar apex aneurysms from January 2001 to December 2009 were retrospectively analyzed.The 12 patients were composed of 5 males and 7 females,and their ages ranged from 21 years to 58 years.Results Nine patients suffered from narrow-necked aneurysms,which were directly embolized,and the other three suffered from wide-necked aneurysms,which were embolized using a microstent.Eight aneurysms were completely embolized,and the other four were partly embolized.No rebleeding occurred within the follow-up period of 12 months to 36 months,and all patients recovered well without neurological defects.Conclusions Therefore,endovascular treatment for ruptured basilar apex aneurysm is a semi-invasive,safe,and effective method.

  7. Numerical analyses in the design of umbrella arch systems

    Institute of Scientific and Technical Information of China (English)

    J. Oke; N. Vlachopoulos; M.S. Diederichs

    2014-01-01

    Due to advances in numerical modelling, it is possible to capture complex support-ground interaction in two dimensions and three dimensions for mechanical analysis of complex tunnel support systems, although such analysis may still be too complex for routine design calculations. One such system is the forepole element, installed within the umbrella arch temporary support system for tunnels, which warrants such support measures. A review of engineering literature illustrates that a lack of design standards exists regarding the use of forepole elements. Therefore, when designing such support, de-signers must employ complex numerical models combined with engineering judgement. With reference to past developments by others and new investigations conducted by the authors on the Driskos tunnel in Greece and the Istanbul metro, this paper illustrates how advanced numerical modelling tools can facilitate understanding of the influences of design parameters associated with the use of forepole ele-ments. In addition, this paper highlights the complexity of the ground-support interaction when simulated with two-dimensional (2D) finite element software using a homogenous reinforced region, and three-dimensional (3D) finite difference software using structural elements. This paper further il-lustrates sequential optimisation of two design parameters (spacing and overlap) using numerical modelling. With regard to capturing system behaviour in the region between forepoles for the purpose of dimensioning spacing, this paper employs three distinctive advanced numerical models:particle codes, continuous finite element models with joint set and Voronoi blocks. Finally, to capture the behaviour/failure ahead of the tunnel face (overlap parameter), 2D axisymmetric models are employed. Finally, conclusions of 2D and 3D numerical assessment on the Driskos tunnel are drawn. The data enriched case study is examined to determine an optimum design, based on the proposed optimisation of

  8. Evaluation of Dynamic Load Factors for a High-Speed Railway Truss Arch Bridge

    Directory of Open Access Journals (Sweden)

    Ding Youliang

    2016-01-01

    Full Text Available Studies on dynamic impact of high-speed trains on long-span bridges are important for the design and evaluation of high-speed railway bridges. The use of the dynamic load factor (DLF to account for the impact effect has been widely accepted in bridge engineering. Although the field monitoring studies are the most dependable way to study the actual DLF of the bridge, according to previous studies there are few field monitoring data on high-speed railway truss arch bridges. This paper presents an evaluation of DLF based on field monitoring and finite element simulation of Nanjing DaShengGuan Bridge, which is a high-speed railway truss arch bridge with the longest span throughout the world. The DLFs in different members of steel truss arch are measured using monitoring data and simulated using finite element model, respectively. The effects of lane position, number of train carriages, and speed of trains on DLF are further investigated. By using the accumulative probability function of the Generalized Extreme Value Distribution, the probability distribution model of DLF is proposed, based on which the standard value of DLF within 50-year return period is evaluated and compared with different bridge design codes.

  9. Research on analysis method for temperature control information of high arch dam construction

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Temperature control,which is directly responsible for the project quality and progress,plays an important role in high arch dam construction.How to discover the rules from a large amount of temperature control information collected in order to guide the adjustment of temperature control measures to prevent cracks on site is the key scientific problem.In this paper,a mathematic logical model was built firstly by means of a coupling analysis of temperature control system decomposition and coordination for high arch dam.Then,an analysis method for temperature control information was presented based on data mining technology.Furthermore,the data warehouse of temperature control was designed,and the artificial neural network forecasting model for the highest temperature of concrete was also developed.Finally,these methods were applied to a practical project. The result showed that the efficiency and precision of temperature control was improved,and rationality and scientificity of management and decision-making were strengthened.All of these researches provided an advanced analysis method for temperature control in the high arch dam construction process.

  10. Maximal aneurysm diameter follow-up is inadequate after endovascular abdominal aortic aneurysm repair

    NARCIS (Netherlands)

    Wever, JJ; Blankensteijn, JD; Mali, WPTM; Eikelboom, BC

    2000-01-01

    Background: follow-up after endovascular abdominal aortic aneurysm repair (EAR) generally consists of serial diameter measurements. A size change after EAR, however, is the consequence of alterations of the excluded aneurysm sac volume. Objective: to assess the agreement between diameter measurement

  11. Aneurysmal wall enhancement and perianeurysmal edema after endovascular treatment of unruptured cerebral aneurysms.

    LENUS (Irish Health Repository)

    Su, I-Chang

    2014-06-01

    Perianeurysmal edema and aneurysm wall enhancement are previously described phenomenon after coil embolization attributed to inflammatory reaction. We aimed to demonstrate the prevalence and natural course of these phenomena in unruptured aneurysms after endovascular treatment and to identify factors that contributed to their development.

  12. The influence of neck thrombus on clinical outcome and aneurysm morphology after endovascular aneurysm repair

    NARCIS (Netherlands)

    F.M.V. Bastos Gonçalves (Frederico); H.J.M. Verhagen (Hence); K. Chinsakchai (Khamin); J.W. van Keulen (Jasper); M.T. Voûte (Michiel); H.J.A. Zandvoort (Herman); F.L. Moll (Frans); J.A. van Herwaarden (Joost)

    2012-01-01

    textabstractObjective: This study investigated the influence of significant aneurysm neck thrombus in clinical and morphologic outcomes after endovascular aneurysm repair (EVAR). Methods: The patient population was derived from a prospective EVAR database from two university institutions in The Neth

  13. Endovascular treatment of late thoracic aortic aneurysms after surgical repair of congenital aortic coarctation in childhood.

    Directory of Open Access Journals (Sweden)

    Robert Juszkat

    Full Text Available BACKGROUND: In some patients, local surgery-related complications are diagnosed many years after surgery for aortic coarctation. The purposes of this study were: (1 to systematically evaluate asymptomatic adults after Dacron patch repair in childhood, (2 to estimate the formation rate of secondary thoracic aortic aneurysms (TAAs and (3 to assess outcomes after intravascular treatment for TAAs. METHODS: This study involved 37 asymptomatic patients (26 female and 11 male who underwent surgical repair of aortic coarctation in the childhood. After they had reached adolescence, patients with secondary TAAs were referred to endovascular repair. RESULTS: Follow-up studies revealed TAA in seven cases (19% (including six with the gothic type of the aortic arch and mild recoarctation in other six (16%. Six of the TAA patients were treated with stentgrafts, but one refused to undergo an endovascular procedure. In three cases, stengrafts covered the left subclavian artery (LSA, in another the graft was implanted distally to the LSA. In two individuals, elective hybrid procedures were performed with surgical bypass to the supraaortic arteries followed by stengraft implantation. All subjects survived the secondary procedures. One patient developed type Ia endoleak after stentgraft implantation that was eventually treated with a debranching procedure. CONCLUSIONS: The long-term course of clinically asymptomatic patients after coarctation patch repair is not uncommonly complicated by formation of TAAs (particularly in individuals with the gothic pattern of the aortic arch that can be treated effectively with stentgrafts. However, in some patients hybrid procedures may be necessary.

  14. Flow Instability and Wall Shear Stress Ocillation in Intracranial Aneurysms

    Science.gov (United States)

    Baek, Hyoungsu; Jayamaran, Mahesh; Richardson, Peter; Karniadakis, George

    2009-11-01

    We investigate the flow dynamics and oscillatory behavior of wall shear stress (WSS) vectors in intracranial aneurysms using high-order spectral/hp simulations. We analyze four patient- specific internal carotid arteries laden with aneurysms of different characteristics : a wide-necked saccular aneurysm, a hemisphere-shaped aneurysm, a narrower-necked saccular aneurysm, and a case with two adjacent saccular aneurysms. Simulations show that the pulsatile flow in aneurysms may be subject to a hydrodynamic instability during the decelerating systolic phase resulting in a high-frequency oscillation in the range of 30-50 Hz. When the aneurysmal flow becomes unstable, both the magnitude and the directions of WSS vectors fluctuate. In particular, the WSS vectors around the flow impingement region exhibit significant spatial and temporal changes in direction as well as in magnitude.

  15. Renal failure after operation for abdominal aortic aneurysm

    DEFF Research Database (Denmark)

    Olsen, P S; Schroeder, T; Perko, M

    1990-01-01

    Among 656 patients undergoing surgery for abdominal aortic aneurysm, 81 patients (12%) developed postoperative renal failure. Before operation hypotension and shock occurred in 88% of the patients with ruptured aneurysm, whereas none of the patients operated electively were hypotensive. Dialysis...

  16. 3D geometric reconstruction of thoracic aortic aneurysms

    Directory of Open Access Journals (Sweden)

    Mohiaddin Raad H

    2006-11-01

    Full Text Available Abstract Background The thoracic aortic aneurysm (TAA is a pathology that involves an expansion of the aortic diameter in the thoracic aorta, leading to risk of rupture. Recent studies have suggested that internal wall stress, which is affected by TAA geometry and the presence or absence of thrombus, is a more reliable predictor of rupture than the maximum diameter, the current clinical criterion. Accurate reconstruction of TAA geometry is a crucial step in patient-specific stress calculations. Methods In this work, a novel methodology was developed, which combines data from several sets of magnetic resonance (MR images with different levels of detail and different resolutions. Two sets of images were employed to create the final model, which has the highest level of detail for each component of the aneurysm (lumen, thrombus, and wall. A reference model was built by using a single set of images for comparison. This approach was applied to two patient-specific TAAs in the descending thoracic aorta. Results The results of finite element simulations showed differences in stress pattern between the coarse and fine models: higher stress values were found with the coarse model and the differences in predicted maximum wall stress were 30% for patient A and 11% for patient B. Conclusion This paper presents a new approach to the reconstruction of an aneurysm model based on the use of several sets of MR images. This enables more accurate representation of not only the lumen but also the wall surface of a TAA taking account of intraluminal thrombus.

  17. Hemodynamic simulations in coronary aneurysms of a patient with Kawasaki Disease

    Science.gov (United States)

    Sengupta, Dibyendu; Marsden, Alison; Burns, Jane

    2010-11-01

    Kawasaki Disease is the leading cause of acquired pediatric heart disease, and can cause large coronary artery aneurysms in untreated cases. A simulation case study has been performed for a 10-year-old male patient with coronary aneurysms. Specialized coronary boundary conditions along with a lumped parameter heart model mimic the interactions between the ventricles and the coronary arteries, achieving physiologic pressure and flow waveforms. Results show persistent low shear stress in the aneurismal regions, and abnormally high shear at the aneurysm neck. Correlation functions have been derived to compare wall shear stress and wall shear stress gradients with recirculation time with the idea of localizing zones of calcification and thrombosis. Results are compared with those of an artificially created normal coronary geometry for the same patient. The long-term goal of this work is to develop links between hemodynamics and thrombotic risk to assist in clinical decision-making.

  18. Thoracic aortic aneurysm: reading the enemy's playbook.

    Science.gov (United States)

    Elefteriades, John A

    2008-05-01

    The vast database of the Yale Center for Thoracic Aortic Disease--which includes information on 3000 patients with thoracic aortic aneurysm or dissection, with 9000 catalogued images and 9000 patient-years of follow-up--has, over the last decade, permitted multiple glimpses into the "playbook" of this virulent disease. Understanding the precise behavioral features of thoracic aortic aneurysm and dissection permits us more effectively to combat this disease. In this monograph, we will first review certain fundamentals--in terms of anatomy, nomenclature, imaging, diagnosis, medical, surgical, and stent treatment. After reviewing these fundamentals, we will proceed with a detailed exploration of lessons learned by peering into the operational playbook of thoracic aortic aneurysm and dissection. Among the glimpses afforded in the behavioral playbook of this disease are the following: 1 Thoracic aortic aneurysm, while lethal, is indolent. Mortality usually does not occur until after years of growth. 2 The aneurysmal ascending thoracic aorta grows slowly: about 0.1 cm per year (the descending aorta grows somewhat faster). 3 Over a patient's lifetime, "hinge points" at which the likelihood of rupture or dissection skyrockets are seen at 5.5 cm for the ascending and 6.5 cm for the descending aorta. Intervening at 5 cm diameter for the ascending and 6 cm for the descending prevents most adverse events. 4 Symptomatic aneurysms require resection regardless of size. 5 The yearly rate of rupture, dissection, or death is 14.1% for a patient with a thoracic aorta of 6 cm diameter. 6 The mechanical properties of the aorta deteriorate markedly at 6 cm diameter (distensibility falls, and wall stress rises)--a finding that "dovetails" perfectly with observations of the clinical behavior of the thoracic aorta. 7 Thoracic aortic aneurysm and dissection are largely inherited diseases, with a predominantly autosomal-dominant pattern. The specific genetics are being elucidated at the

  19. Traumatic aneurysms of the intracranial and cervical vessels: A review

    Directory of Open Access Journals (Sweden)

    Kamlesh S Bhaisora

    2016-01-01

    Full Text Available Traumatic intracranial aneurysms (TICA are rare in occurrence, constituting less than 1% of the total cases of intracranial aneurysms. Cervical posttraumatic aneurysms arising from major blood vessels supplying the brain are also extremely rare. Their variable locations, morphological variations and the presence of concomitant head injury makes their diagnosis and treatment a challenge. In this review, we discuss the epidemiology, etiology, classification and management issues related to TICA as well as traumatic neck aneurysms and review the pertinent literature.

  20. Distal posterior inferior cerebellar artery aneurysm in a child

    Directory of Open Access Journals (Sweden)

    J. Francisco Salomão

    1992-06-01

    Full Text Available The case of a 7-year-old boy presenting with recurrent episodes of subarachnoid hemorrhage due to a distal posterior inferior cerebellar artery aneurysm (PICA, successfully operated, is reported.' The low incidence of intracranial aneurysms in the first decade of life and the rare occurrence of distal PICA aneurysms are unusual features of this case. The theories regarding the origin of intracranial berry aneurysms are discussed.

  1. Elastic responses of underground circular arches considering dynamic soil-structure interaction: A theoretical analysis

    Science.gov (United States)

    Chen, Hai-Long; Jin, Feng-Nian; Fan, Hua-Lin

    2013-02-01

    Due to the wide applications of arches in underground protective structures, dynamic analysis of circular arches including soil-structure interactions is important. In this paper, an exact solution of the forced vibration of circular arches subjected to subsurface denotation forces is obtained. The dynamic soil-structure interaction is considered with the introduction of an interfacial damping between the structure element and the surrounding soil into the equation of motion. By neglecting the influences of shear, rotary inertia and tangential forces and assuming the arch incompressible, the equations of motion of the buried arches were set up. Analytical solutions of the dynamic responses of the protective arches were deduced by means of modal superposition. Arches with different opening angles, acoustic impedances and rise-span ratios were analyzed to discuss their influences on an arch. The theoretical analysis suggests blast loads for elastic designs and predicts the potential failure modes for buried protective arches.

  2. Regenerative material for aneurysm embolization A 3-dimensional culture system of fibroblasts and calcium alginate gel

    Institute of Scientific and Technical Information of China (English)

    Jingdong Zhang; Kan Xu; Jinlu Yu; Jun Wang; Qi Luo

    2011-01-01

    Calcium alginate gel (CAG) has been shown to successfully model aneurysm embolization within a short period of time. However, gradually degrading CAG potentially results in aneurysm recanalization.In the present study, a regenerative embolic material was designed by seeding rat fibroblasts in a CAG. The study investigated the feasibility of constructing a 3-dimensional culture system. The fibroblasts grew well and firmly attached to the CAG. CAG was conducive for fibroblast growth, and resulted in a 3-dimensional culture system. Results show that CAG can be used theoretically as a vascular, regenerative, embolic material.

  3. [Relationship between aortic arch shape and blood pressure response after coarctation repair].

    Science.gov (United States)

    Ou, P; Mousseaux, E; Auriacombe, L; Pédroni, E; Balleux, F; Sidi, D; Bonnet, D

    2005-01-01

    The mechanisms of secondary hypertension after repair of coarctation of the aorta are not well understood. Abnormalities of the architecture of the aortic arch and their consequences on blood pressure have not been studied. In order to study the relationship between abnormalities or aortic arch architecture and resting blood pressure ninety-four patients without re-coarctation were followed up prospectively from 1997 to 2004 (mean age 16.9 +/- 8.1 years; mean weight 57.5 +/- 18.3 Kg; interval since surgery 16.3 +/- 5.4 years). All underwent MRI angiography of the thoracic aorta which enabled the abnormalities to be classified in 3 groups: gothic arch, crenellated arch and roman arch. Twenty-four patients (25.5%) were hypertensive and 70 (74.4%) normotensive. There were 40 gothic arches (42.5%). 14 crenellated arches (15%) and 40 roman arches (42.5%). Gothic arches were more commonly observed in the hypertensive patients (18/40, [45%, 95% CI 31-62]) than the crenellated arches (4/14, [28.5%, 95% CI 7-48]) or the roman arches (2/40, [5%, 95% CI 2-12]). Only the gothic arch was independently correlated with hypertension on multivariate analysis. The authors conclude that gothic deformation of the aortic arch is an independent predictive factor of hypertension in patients operated for coarctation with an excellent result on the isthmic region. Patients with a gothic appearance of their aortic arch should be followed up closely.

  4. PDR Emission from the Arched-Filaments and Nearby Positions

    CERN Document Server

    García, P; Abel, N; Steinke, M; Burton, M; Blackwell, R

    2016-01-01

    We investigate the physical conditions of the gas, atomic and molecular, in the filaments in the context of Photo-Dissociation Regions (PDRs) using the KOSMA-PDR mode of clumpy clouds. We also compare the [CII] vs. [NII] integrated intensity predictions in Abel et al. 2005 for HII regions and adjacent PDRs in the Galactic disk, and check for their applicability under the extreme physical conditions present in the GC. Our preliminary results show that observed integrated intensities are well reproduced by the PDR model. The gas is exposed to a relatively low Far-UV field between 10^2 - 10^3 Draine fields. The total volume hydrogen density is well constrained between 10^4 - 10^5 cm^-3. The hydrogen ionization rate due to cosmic-rays varies between 10^-15 and 4x10^-15 s^-1, with the highest value ~ 10^-14 s^-1 found towards G0.07+0.04. Our results show that the line-of-sight contribution to the total distance of the filaments to the Arches Cluster is not negligible. The spatial distribution of the [CII]/[NII] ra...

  5. Three-dimensional dental arch curvature in human adolescents and adults.

    Science.gov (United States)

    Ferrario, V F; Sforza, C; Poggio, C E; Serrao, G; Colombo, A

    1999-04-01

    The three-dimensional arrangement of dental cusps and incisal edges in human dentitions has been reported to fit the surface of a sphere (the curve of Monson), with a radius of about 4 inches in adults. The objective of the current study was to compare the three-dimensional curvature of the mandibular dental arch in healthy permanent dentitions of young adults and adolescents. The mandibular casts of 50 adults (aged 19 to 22 years) and 20 adolescents (aged 12 to 14 years) with highly selected sound dentitions that were free from temporomandibular joint problems were obtained. The three coordinates of cusp tips excluding the third molars were digitized with a three-dimensional digitizer, and used to derive a spherical model of the curvature of the occlusal surfaces. From the best interpolating sphere, the radii of the left and right curves of Spee (quasi-sagittal plane) and of molar curve of Wilson (frontal plane) were computed. Mandibular arch size (interdental distances) was also calculated. The occlusal curvature of the mandibular arch was not significantly influenced by sex, although a significant effect of age was found (Student t, P curves of Spee, and curve of Wilson in the molar area were about 101 mm in adults, and about 80 mm in adolescents. Arch size was not influenced by either sex or age. The different curvatures of the occlusal plane in adolescents and adults may be explained by a progressive rotation of the major axis of the teeth moving the occlusal plane toward a more buccal position. These dental movements should be performed in a frontal plane on an anteroposterior axis located next to the dental crown.

  6. Epidemiology and genetics of intracranial aneurysms.

    Science.gov (United States)

    Caranci, F; Briganti, F; Cirillo, L; Leonardi, M; Muto, M

    2013-10-01

    Intracranial aneurysms are acquired lesions (5-10% of the population), a fraction of which rupture leading to subarachnoid hemorrhage with devastating consequences. Until now, the exact etiology of intracranial aneurysms formation remains unclear. The low incidence of subarachnoid hemorrhage in comparison with the prevalence of unruptured IAs suggests that the vast majority of intracranial aneurysms do not rupture and that identifying those at highest risk is important in defining the optimal management. The most important factors predicting rupture are aneurysm size and site. In addition to ambiental factors (smoking, excessive alcohol consumption and hypertension), epidemiological studies have demonstrated a familiar influence contributing to the pathogenesis of intracranial aneurysms, with increased frequency in first- and second-degree relatives of people with subarachnoid hemorrhage. In comparison to sporadic aneurysms, familial aneurysms tend to be larger, more often located at the middle cerebral artery, and more likely to be multiple. Other than familiar occurrence, there are several heritable conditions associated with intracranial aneurysm formation, including autosomal dominant polycystic kidney disease, neurofibromatosis type I, Marfan syndrome, multiple endocrine neoplasia type I, pseudoxanthoma elasticum, hereditary hemorrhagic telangiectasia, and Ehlers-Danlos syndrome type II and IV. The familial occurrence and the association with heritable conditions indicate that genetic factors may play a role in the development of intracranial aneurysms. Genome-wide linkage studies in families and sib pairs with intracranial aneurysms have identified several loci on chromosomes showing suggestive evidence of linkage, particularly on chromosomes 1p34.3-p36.13, 7q11, 19q13.3, and Xp22. For the loci on 1p34.3-p36.13 and 7q11, a moderate positive association with positional candidate genes has been demonstrated (perlecan gene, elastin gene, collagen type 1 A2 gene

  7. Epidemiology and genetics of intracranial aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Caranci, F., E-mail: ferdinandocaranci@libero.it [Unit of Neuroradiology, Department of Diagnostic Radiology and Radiotherapy, Federico II University, Naples (Italy); Briganti, F., E-mail: frabriga@unina.it [Unit of Neuroradiology, Department of Diagnostic Radiology and Radiotherapy, Federico II University, Naples (Italy); Cirillo, L.; Leonardi, M. [Neuroradiology service, Bellaria Hospital, Bologna (Italy); Muto, M., E-mail: mutomar@tiscali.it [Neuroradiology Service Cardarelli Hospital Naples (Italy)

    2013-10-01

    Intracranial aneurysms are acquired lesions (5–10% of the population), a fraction of which rupture leading to subarachnoid hemorrhage with devastating consequences. Until now, the exact etiology of intracranial aneurysms formation remains unclear. The low incidence of subarachnoid hemorrhage in comparison with the prevalence of unruptured IAs suggests that the vast majority of intracranial aneurysms do not rupture and that identifying those at highest risk is important in defining the optimal management. The most important factors predicting rupture are aneurysm size and site. In addition to ambiental factors (smoking, excessive alcohol consumption and hypertension), epidemiological studies have demonstrated a familiar influence contributing to the pathogenesis of intracranial aneurysms, with increased frequency in first- and second-degree relatives of people with subarachnoid hemorrhage. In comparison to sporadic aneurysms, familial aneurysms tend to be larger, more often located at the middle cerebral artery, and more likely to be multiple. Other than familiar occurrence, there are several heritable conditions associated with intracranial aneurysm formation, including autosomal dominant polycystic kidney disease, neurofibromatosis type I, Marfan syndrome, multiple endocrine neoplasia type I, pseudoxanthoma elasticum, hereditary hemorrhagic telangiectasia, and Ehlers-Danlos syndrome type II and IV. The familial occurrence and the association with heritable conditions indicate that genetic factors may play a role in the development of intracranial aneurysms. Genome-wide linkage studies in families and sib pairs with intracranial aneurysms have identified several loci on chromosomes showing suggestive evidence of linkage, particularly on chromosomes 1p34.3–p36.13, 7q11, 19q13.3, and Xp22. For the loci on 1p34.3–p36.13 and 7q11, a moderate positive association with positional candidate genes has been demonstrated (perlecan gene, elastin gene, collagen type 1 A2

  8. Fatigue Performance Assessment of Composite Arch Bridge Suspenders Based on Actual Vehicle Loads

    Directory of Open Access Journals (Sweden)

    Bin Chen

    2015-01-01

    Full Text Available In the through arch bridges, the suspenders are the key components connecting the arch rib and the bridge deck in the middle, and their safety is an increasing focus in the field of bridge engineering. In this study, various vehicle traffic flow parameters are investigated based on the actual vehicle data acquired from the long-term structural health monitoring system of a composite arch bridge. The representative vehicle types and the probability density functions of several parameters are determined, including the gross vehicle weight, axle weight, time headway, and speed. A finite element model of the bridge structure is constructed to determine the influence line of the cable force for various suspenders. A simulated vehicle flow, generated using the Monte Carlo method, is applied on the influence lines of the target suspender to determine the stress process, and then the stress amplitude spectrum is obtained based on the statistical analysis of the stress process using the rainflow counting method. The fatigue performance levels of various suspenders are analyzed according to the Palmgren-Miner linear cumulative damage theory, which helps to manage the safety of the suspenders.

  9. Ruptured Intracranial Mycotic Aneurysm in Infective Endocarditis: A Natural History

    Directory of Open Access Journals (Sweden)

    Isabel Kuo

    2010-01-01

    discovered on CT Angiography. His lesion quickly progressed into an intraparenchymal hemorrhage, requiring emergent craniotomy and aneurysm clipping. Current recommendations on the management of intracranial Mycotic Aneurysms are based on few retrospective case studies. The natural history of the patient's ruptured aneurysm is presented, as well as a literature review on the management and available treatment modalities.

  10. [Giant intracranial aneurysm in three years old boy: case report].

    Science.gov (United States)

    de Tella, Osvaldo Inácio; Crosera, João Francisco; Herculano, Marco Antonio; de Paiva Neto, Manoel Antonio

    2006-06-01

    Cerebral aneurysms are rare in the pediatric age group and differ from adults' aneurysms in size, localization and incidence. We report a 3-year-old boy with giant middle cerebral artery aneurysms who presented with subarachnoid hemorrhage. The patient was submitted to surgical treatment and the postoperative period was uneventful.

  11. Morphological predictors of posterior communicating artery aneurysms rupture

    Institute of Scientific and Technical Information of China (English)

    Nan Lv; Yibin Fang; Ying Yu; Jinyu Xu; Jianmin Liu; Qinghai Huang

    2015-01-01

    Objective:The conflicting findings of previous morphological studies on intracranial aneurysm rupture may be caused by the different locations of aneurysms. We aimed to determine the independent risk factors of aneurysm rupture by focusing on only posterior communicating artery (PcomA) aneurysms. Methods:In 89 PcomA aneurysms (58 ruptured, 31 unruptured), clinical and morphological characteristics were compared between the ruptured and unruptured groups. Multivariate logistic regression analysis was performed to determine the independent predictors for the rupture status of PcomA aneurysms. Results:In univariate analyses, the aneurysm dome size, aspect ratio, size ratio, dome‐to‐neck ratio, and inflow angle were significant parameters. With multivariate analyses, only the aneurysm dome size and inflow angle were significantly associated with the rupture status of PcomA aneurysms. Conclusions:Morphology was related with rupture of PcomA aneurysms. The aneurysm dome size and inflow angle were found to be the independent parameters characterizing the rupture status of PcomA aneurysms.

  12. Endovascular reconstruction of aneurysms with a complex geometry

    Directory of Open Access Journals (Sweden)

    Vipul Gupta

    2016-01-01

    Full Text Available Conventional endovascular coiling remains the mainstay of treatment for most aneurysms; however, it may not be suitable for aneurysms with a complex geometry and there remains the risk of recanalization. Aneurysms with an unfavorable morphology are difficult to treat through both endovascular and surgical means. Progress in endovascular technology has allowed for the emergence of newer strategies to treat aneurysms with a complex geometry. Better packing density in wide-necked and large aneurysms can be achieved through the balloon remodeling technique. Similarly, a self-expanding stent cannot only act as a scaffold that helps to retain coils but also aids in diverting the blood flow away from the aneurysm sac. Lately, focus has shifted from endosaccular occlusion to endoluminal reconstruction; flow diverters are being increasingly used to treat aneurysms with an unfavorable geometry. However, there is no clear consensus on the best endovascular management strategy in certain subset of aneurysms - large and giant internal carotid aneurysms, blister aneurysms, and fusiform/dissecting aneurysms of the vertebrobasilar artery. We present a review of literature and discuss the current evidence for the various endovascular strategies to treat complex aneurysms.

  13. Renovascular hypertension and intrarenal artery aneurysms in a preschool child

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, David J.; Barletta, Gina-Marie; Bunchman, Timothy E. [Michigan State University College of Human Medicine, Grand Rapids, MI (United States); Helen DeVos Children' s Hospital, Pediatric Nephrology, Dialysis and Transplantation, Grand Rapids, MI (United States); Mowry, Jeanne A. [Oregon Health Sciences University, Pediatric Nephrology, Northwest Permanente, P.C. and Doernbecher Children' s Hospital, Portland, OR (United States)

    2009-09-15

    Renovascular hypertension from renal artery aneurysmal formation is a rare complication of fibromuscular dysplasia. Few data exist to direct the management of intrarenal artery aneurysms in pediatric patients. We report the presentation, diagnosis and management of renovascular hypertension and intrarenal aneurysmal disease in a preschool child. (orig.)

  14. Characterization of the cephalic arch and location of stenosis

    Science.gov (United States)

    Bennett, Shelby; Hammes, Mary S.; Blicharski, Tom; Watson, Sydeaka; Funaki, Brian

    2015-01-01

    Purpose The purpose of this study is to accurately characterize the cephalic arch segments into four domains and to enable more specific evaluation of cephalic arch stenosis (CAS) and determine the frequency of stenosis in each domain. Methods After Institutional Review Board (IRB) approval, a retrospective chart review was done to define a population of patients receiving hemodialysis who developed CAS as apparent on clinically indicated radiologic imaging. A standardized approach was devised to categorize four domains of the cephalic arch. Domain I was defined as the peripheral portion of the arch and Domain IV was the distal portion of the cephalic vein near termination with the axillary vein. The magnitude of stenosis as measured by percentage was determined and compared in the four domains. Results The most frequent location for stenosis was found in domain IV when compared with domains II or I (p<0.01). The magnitude of stenosis differed across all domains (p<0.001) with the least common place for CAS in domain I. Treatment of CAS included angioplasty in all, thrombectomy in eight, and stent placement in five. Conclusions CAS occurs most commonly in the terminal portion of the arch. Four standardized domains have been defined; future work will validate these findings and determine the best intervention for each domain. PMID:25198819

  15. Three-dimensional stiffness of the carpal arch.

    Science.gov (United States)

    Gabra, Joseph N; Li, Zong-Ming

    2016-01-01

    The carpal arch of the wrist is formed by irregularly shaped carpal bones interconnected by numerous ligaments, resulting in complex structural mechanics. The purpose of this study was to determine the three-dimensional stiffness characteristics of the carpal arch using displacement perturbations. It was hypothesized that the carpal arch would exhibit an anisotropic stiffness behavior with principal directions that are oblique to the conventional anatomical axes. Eight (n=8) cadavers were used in this study. For each specimen, the hamate was fixed to a custom stationary apparatus. An instrumented robot arm applied three-dimensional displacement perturbations to the ridge of trapezium and corresponding reaction forces were collected. The displacement-force data were used to determine a three-dimensional stiffness matrix using least squares fitting. Eigendecomposition of the stiffness matrix was used to identify the magnitudes and directions of the principal stiffness components. The carpal arch structure exhibited anisotropic stiffness behaviors with a maximum principal stiffness of 16.4±4.6N/mm that was significantly larger than the other principal components of 3.1±0.9 and 2.6±0.5N/mm (pcarpal tunnel which is accounted for by the stiff transverse ligaments that tightly bind distal carpal arch. The minimal principal stiffness is attributed to the less constraining articulation between the trapezium and scaphoid. This study provides advanced characterization of the wrist׳s three-dimensional structural stiffness for improved insight into wrist biomechanics, stability, and function.

  16. 牙弓曲线发生器的运动规划与仿真%Motion Planning and Simulation of Dental Arch Generator

    Institute of Scientific and Technical Information of China (English)

    姜金刚; 张永德

    2013-01-01

    针对牙弓曲线发生器需要协调控制的特点,对牙弓曲线发生器的运动规划进行了研究.基于牙弓曲线幂函数模型构建了牙弓曲线发生器,并进行了运动分析,基于弧长不变理论进行了牙弓曲线发生器控制点运动计算;提出基于牙弓参数等增量法实现了牙弓曲线发生器的运动规划,仿真结果表明:牙弓参数等增量规划法在牙弓曲线发生器运动过程中von mises应力最小,牙弓曲线发生器运动实际轨迹与仿真、理论轨迹近似吻合,结果证实了采用牙弓参数等增量法实现牙弓曲线发生器运动规划的可行性.%Aiming to the characteristics of coordinated control for dental arch generator, motion planning of dental arch generator is studied. Based on power function model of dental arch, dental arch generator is established. Control point positions of dental arch generator are calculated by the arc length constant theory. Dental arch parameter equal increment method is proposed to realize motion planning of dental arch generator. The results show that the maximum von mises hot spots of method 3 for the dental arch generator is small compared to other methods. The experimental motion trajectory of the dental arch generator is approximately in agreement with the simulation and theoretical motion trajectory. The results prove that it is feasible to realize motion planning of dental arch generator using the dental arch parameter equal increment method.

  17. Intracranial aneurysm risk factor genes: relationship with intracranial aneurysm risk in a Chinese Han population.

    Science.gov (United States)

    Zhang, L T; Wei, F J; Zhao, Y; Zhang, Z; Dong, W T; Jin, Z N; Gao, F; Gao, N N; Cai, X W; Li, N X; Wei, W; Xiao, F S; Yue, S Y; Zhang, J N; Yang, S Y; Li, W D; Yang, X Y

    2015-06-18

    Few studies have examined the genes related to risk fac-tors that may contribute to intracranial aneurysms (IAs). This study in Chinese patients aimed to explore the relationship between IA and 28 gene loci, proven to be associated with risk factors for IA. We recruited 119 patients with aneurysms and 257 controls. Single factor and logistic regression models were used to analyze the association of IA and IA rup-ture with risk factors. Twenty-eight single nucleotide polymorphisms (SNPs) in 22 genes were genotyped for the patient and control groups. SNP genotypes and allele frequencies were analyzed by the chi-square test. Logistic regression analysis identified hypertension as a factor that increased IA risk (P = 1.0 x 10(-4); OR, 2.500; 95%CI, 1.573-3.972); IA was associated with two SNPs in the TSLC2A9 gene: rs7660895 (P = 0.007; OR, 1.541; 95%CI, 1.126-2.110); and in the TOX gene: rs11777927 (P = 0.013; OR, 1.511; 95%CI, 1.088-2.098). Subsequent removal of the influence of family relationship identified between 12 of 119 patients enhanced the significant association of these SNPs with IA (P = 0.001; OR, 1.691; 95%CI, 1.226-2.332; and P = 0.006; OR, 1.587; 95%CI, 1.137-2.213 for rs7660895 and rs11777927, respectively). Fur-thermore, the minor allele of rs7660895 (A) was also associated with IA rupture (P = 0.007; OR, 2.196; 95%CI, 1.230-3.921). Therefore, hypertension is an independent risk factor for IA. Importantly, the TSL-C2A9 (rs7660895) and TOX (rs11777927) gene polymorphisms may be associated with formation of IAs, and rs7660895 may be associated with IA rupture.

  18. Flap endonucleases pass 5'-flaps through a flexible arch using a disorder-thread-order mechanism to confer specificity for free 5'-ends.

    Science.gov (United States)

    Patel, Nikesh; Atack, John M; Finger, L David; Exell, Jack C; Thompson, Peter; Tsutakawa, Susan; Tainer, John A; Williams, David M; Grasby, Jane A

    2012-05-01

    Flap endonucleases (FENs), essential for DNA replication and repair, recognize and remove RNA or DNA 5'-flaps. Related to FEN specificity for substrates with free 5'-ends, but controversial, is the role of the helical arch observed in varying conformations in substrate-free FEN structures. Conflicting models suggest either 5'-flaps thread through the arch, which when structured can only accommodate single-stranded (ss) DNA, or the arch acts as a clamp. Here we show that free 5'-termini are selected using a disorder-thread-order mechanism. Adding short duplexes to 5'-flaps or 3'-streptavidin does not markedly impair the FEN reaction. In contrast, reactions of 5'-streptavidin substrates are drastically slowed. However, when added to premixed FEN and 5'-biotinylated substrate, streptavidin is not inhibitory and complexes persist after challenge with unlabelled competitor substrate, regardless of flap length or the presence of a short duplex. Cross-linked flap duplexes that cannot thread through the structured arch react at modestly reduced rate, ruling out mechanisms involving resolution of secondary structure. Combined results explain how FEN avoids cutting template DNA between Okazaki fragments and link local FEN folding to catalysis and specificity: the arch is disordered when flaps are threaded to confer specificity for free 5'-ends, with subsequent ordering of the arch to catalyze hydrolysis.

  19. Classification of the height and flexibility of the medial longitudinal arch of the foot

    DEFF Research Database (Denmark)

    Nilsson, Mettte Kjaergaard; Friis, Rikke; Michaelsen, Maria Skjoldahl

    2012-01-01

    BACKGROUND: The risk of developing injuries during standing work may vary between persons with different foot types. High arched and low arched feet, as well as rigid and flexible feet, are considered to have different injury profiles, while those with normal arches may sustain fewer injuries......-off values presented in this study can be used to categorize people performing standing work into groups of different foot arch types. The results of this study are important for investigating a possible link between arch height and arch movement and the development of injuries....

  20. Proper motions of the Arches cluster with Keck-LGS Adaptive Optics: the first kinematic mass measurement of the Arches

    CERN Document Server

    Clarkson, Will; Morris, Mark; Lu, Jessica; Stolte, Andrea; McCrady, Nate; Do, Tuan; Yelda, Sylvana

    2011-01-01

    We report the first detection of the intrinsic velocity dispersion of the Arches cluster - a young (~2 Myr), massive (~10,000 Solar Mass) starburst cluster located near the Galactic center. This was accomplished using proper motion measurements within the central region of the cluster, obtained with the laser guide star adaptive optics system at Keck Observatory over a 3 year time baseline (2006-2009). This uniform dataset results in proper motion measurements that are improved by a factor ~5 over previous measurements from heterogeneous instruments, yielding internal velocity dispersion estimates 0.15 +/- 0.01 mas/yr, which corresponds to 5.4 +/- 0.4 km/s at a distance of 8.4 kpc. Projecting a simple model for the cluster onto the sky to compare with our proper motion dataset, in conjunction with surface density data, we estimate the total present-day mass of the cluster to be 15,000 (+7400 -6000) Solar masses. The mass in stars observed within a cylinder of radius R=0.4 pc is found to be 9000 (+4000 -3500) ...