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Sample records for vessel wall showed

  1. Vessel wall characterization using quantitative MRI: what's in a number?

    Science.gov (United States)

    Coolen, Bram F; Calcagno, Claudia; van Ooij, Pim; Fayad, Zahi A; Strijkers, Gustav J; Nederveen, Aart J

    2018-02-01

    The past decade has witnessed the rapid development of new MRI technology for vessel wall imaging. Today, with advances in MRI hardware and pulse sequences, quantitative MRI of the vessel wall represents a real alternative to conventional qualitative imaging, which is hindered by significant intra- and inter-observer variability. Quantitative MRI can measure several important morphological and functional characteristics of the vessel wall. This review provides a detailed introduction to novel quantitative MRI methods for measuring vessel wall dimensions, plaque composition and permeability, endothelial shear stress and wall stiffness. Together, these methods show the versatility of non-invasive quantitative MRI for probing vascular disease at several stages. These quantitative MRI biomarkers can play an important role in the context of both treatment response monitoring and risk prediction. Given the rapid developments in scan acceleration techniques and novel image reconstruction, we foresee the possibility of integrating the acquisition of multiple quantitative vessel wall parameters within a single scan session.

  2. 2D Fast Vessel Visualization Using a Vessel Wall Mask Guiding Fine Vessel Detection

    Directory of Open Access Journals (Sweden)

    Sotirios Raptis

    2010-01-01

    and then try to approach the ridges and branches of the vasculature's using fine detection. Fine vessel screening looks into local structural inconsistencies in vessels properties, into noise, or into not expected intensity variations observed inside pre-known vessel-body areas. The vessels are first modelled sufficiently but not precisely by their walls with a tubular model-structure that is the result of an initial segmentation. This provides a chart of likely Vessel Wall Pixels (VWPs yielding a form of a likelihood vessel map mainly based on gradient filter's intensity and spatial arrangement parameters (e.g., linear consistency. Specific vessel parameters (centerline, width, location, fall-away rate, main orientation are post-computed by convolving the image with a set of pre-tuned spatial filters called Matched Filters (MFs. These are easily computed as Gaussian-like 2D forms that use a limited range sub-optimal parameters adjusted to the dominant vessel characteristics obtained by Spatial Grey Level Difference statistics limiting the range of search into vessel widths of 16, 32, and 64 pixels. Sparse pixels are effectively eliminated by applying a limited range Hough Transform (HT or region growing. Major benefits are limiting the range of parameters, reducing the search-space for post-convolution to only masked regions, representing almost 2% of the 2D volume, good speed versus accuracy/time trade-off. Results show the potentials of our approach in terms of time for detection ROC analysis and accuracy of vessel pixel (VP detection.

  3. Role of arginase in vessel wall remodeling

    Directory of Open Access Journals (Sweden)

    William eDurante

    2013-05-01

    Full Text Available Arginase metabolizes the semi-essential amino acid L-arginine to L-ornithine and urea. There are two distinct isoforms of arginase, arginase I and II, which are encoded by separate genes and display differences in tissue distribution, subcellular localization, and molecular regulation. Blood vessels express both arginase I and II but their distribution appears to be cell-, vessel-, and species-specific. Both isoforms of arginase are induced by numerous pathologic stimuli and contribute to vascular cell dysfunction and vessel wall remodeling in several diseases. Clinical and experimental studies have documented increases in the expression and/or activity of arginase I or II in blood vessels following arterial injury and in pulmonary and arterial hypertension, aging, and atherosclerosis. Significantly, pharmacological inhibition or genetic ablation of arginase in animals ameliorates abnormalities in vascular cells and normalizes blood vessel architecture and function in all of these pathological states. The detrimental effect of arginase in vascular remodeling is attributable to its ability to stimulate vascular smooth muscle cell and endothelial cell proliferation, and collagen deposition by promoting the synthesis of polyamines and L-proline, respectively. In addition, arginase adversely impacts arterial remodeling by directing macrophages towards an inflammatory phenotype. Moreover, the proliferative, fibrotic, and inflammatory actions of arginase in the vasculature are further amplified by its capacity to inhibit nitric oxide synthesis by competing with nitric oxide synthase for substrate, L-arginine. Pharmacologic or molecular approaches targeting specific isoforms of arginase represent a promising strategy in treating obstructive fibroproliferative vascular disease.

  4. Walled Carotid Bifurcation Phantoms for Imaging Investigations of Vessel Wall Motion and Blood Flow Dynamics.

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    Chee, Adrian J Y; Ho, Chung Kit; Yiu, Billy Y S; Yu, Alfred C H

    2016-07-18

    As a major application domain of vascular ultrasound, the carotid artery has long been the subject of anthropomorphic phantom design. It is nevertheless not trivial to develop walled carotid phantoms that are compatible for use in integrative imaging of carotid wall motion and flow dynamics. In this paper, we present a novel phantom design protocol that can enable efficient fabrication of walled carotid bifurcation phantoms with: (i) high acoustic compatibility, (ii) artery-like vessel elasticity, and (iii) stenotic narrowing feature. Our protocol first involved direct fabrication of the vessel core and an outer mold using computer-aided design tools and 3-D printing technology; these built parts were then used to construct an elastic vessel tube through investment casting of a polyvinyl alcohol containing mixture, and an agar-gelatin tissue mimicking slab was formed around the vessel tube. For demonstration, we applied our protocol to develop a set of healthy and stenosed (25%, 50%, 75%) carotid bifurcation phantoms. Plane wave imaging experiments were performed on these phantoms using an ultrasound scanner with channel-level configurability. Results show that the wall motion dynamics of our phantoms agreed with pulse wave propagation in an elastic vessel (pulse wave velocity of 4.67±0.71 m/s measured at the common carotid artery), and their flow dynamics matched the expected ones in healthy and stenosed bifurcation (recirculation and flow jet formation observed). Integrative imaging of vessel wall motion and blood flow dynamics in our phantoms was also demonstrated, from which we observed fluid-structure interaction differences between healthy and diseased bifurcation phantoms. These findings show that the walled bifurcation phantoms developed with our new protocol are useful in vascular imaging studies that individually or jointly assess wall motion and flow dynamics.

  5. Intracranial vessel wall imaging at 7.0 tesla MRI

    NARCIS (Netherlands)

    van der Kolk, A.G.

    2014-01-01

    Intracranial atherosclerosis is one of the main causes of ischemic stroke. Current conventional imaging techniques assessing intracranial arterial disease in vivo only visualize the vessel wall lumen instead of the pathological vessel wall itself. Therefore, not much is known about the imaging

  6. High-resolution intracranial vessel wall MRI in an elderly asymptomatic population: comparison of 3T and 7T

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    Harteveld, Anita A.; Kolk, Anja G. van der; Dieleman, Nikki; Siero, Jeroen C.W.; Luijten, Peter R.; Zwanenburg, Jaco J.M.; Hendrikse, Jeroen [University Medical Center Utrecht, Department of Radiology, Postbox 85500, Utrecht (Netherlands); Worp, H.B. van der; Frijns, Catharina J.M. [University Medical Center Utrecht, Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, Utrecht (Netherlands); Kuijf, Hugo J. [University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands)

    2017-04-15

    Several intracranial vessel wall sequences have been described in recent literature, with either 3-T or 7-T magnetic resonance imaging (MRI). In the current study, we compared 3-T and 7-T MRI in visualising both the intracranial arterial vessel wall and vessel wall lesions. Twenty-one elderly asymptomatic volunteers were scanned by 3-T and 7-T MRI with an intracranial vessel wall sequence, both before and after contrast administration. Two raters scored image quality, and presence and characteristics of vessel wall lesions. Vessel wall visibility was equal or significantly better at 7 T for the studied arterial segments, even though there were more artefacts hampering assessment. The better visualisation of the vessel wall at 7 T was most prominent in the proximal anterior cerebral circulation and the posterior cerebral artery. In the studied elderly asymptomatic population, 48 vessel-wall lesions were identified at 3 T, of which 7 showed enhancement. At 7 T, 79 lesions were identified, of which 29 showed enhancement. Seventy-one percent of all 3-T lesions and 59 % of all 7-T lesions were also seen at the other field strength. Despite the large variability in detected lesions at both field strengths, we believe 7-T MRI has the highest potential to identify the total burden of intracranial vessel wall lesions. (orig.)

  7. Magnetic resonance imaging of vessel wall morphology and function

    NARCIS (Netherlands)

    Kröner, Eleanore Sophie Jeanine

    2015-01-01

    This thesis evaluates morphological and functional vessel wall properties measured by magnetic resonance imaging techniques in healthy volunteers and patients with various diseases (i.e. Marfan syndrome patients (MFS), patients with thoracic aortic aneurysm and patients with a previous myocardial

  8. Force acting on spheres adhered to a vessel wall.

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    Sugihara-Seki, M; Skalak, R

    1997-01-01

    To evaluate the force and torque acting on leukocytes attached to the vessel wall, we numerically study the flow field around the leukocytes by using rigid spherical particles adhered to the wall of a circular cylindrical tube as a model of adherent leukocytes. The adherent particles are assumed to be placed regularly in the flow direction with equal spacings, in one row or two rows. The flow field of the suspending fluid is analyzed by a finite element method applied to the Stokes equations, and the drag force and torque acting on each particle, as well as the apparent viscosity, are evaluated as a function of the particle to tube diameter ratio and the particle arrangements. For two-row arrangements of adhered particles where neighboring particles are placed alternately on opposite sides of the vessel, the drag and the torque exerted on each particle are higher than those for single-row arrangements, for constant particle to tube diameter ratio and axial spacing between neighboring particles. This is enhanced for larger particles and smaller axial spacings. The apparent viscosity of the flow through vessels with adhered particles is found to be significantly higher than that without adhered particles or when the particles are freely floating through the vessels.

  9. Coagulation and the vessel wall in thrombosis and atherosclerosis.

    Science.gov (United States)

    Kleinegris, Marie-Claire; Ten Cate-Hoek, Arina J; Ten Cate, Hugo

    2012-01-01

    The blood coagulation system is a key survival mechanism that has developed to protect man against lethal bleeding. A second function of blood coagulation is its close interaction with immunity. The immune-mediated coagulation responses may broadly be regarded as an element of response to injury. Pathological coagulation responses, including thromboembolism and disseminated intravascular coagulation (DIC), could therefore be regarded as excessive immune responses to a vessel wall injury. Virchow's triad, which comprises changes in the components of the blood, the state of the vessel wall, and the blood flow, was originally proposed for venous thrombosis. However, lately it appears that the same principles can be applied to arterial thrombosis and even DIC. It has even been postulated that all forms of thrombosis may be part of a continuous spectrum of the same disease. Over the past few years, an accumulation of evidence has shown that the etiopathogenetic mechanisms behind venous and arterial thrombosis are quite similar. The traditional elements of Virchow's triad are found to apply to both arterial and venous thrombosis. Yet, nowadays more emphasis is placed on the vessel wall and vascular bed specificity and the interaction with inflammation and hypercoagulability. This narrative review will discuss recent advances in research on the possible interactions between coagulation, the vascular endothelium, and atherosclerosis as well as the consequences of such interactions for venous and arterial thrombosis.

  10. Molecular magnetic resonance imaging of atherosclerotic vessel wall disease

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    Noerenberg, Dominik [Charite - University Medicine Berlin, Department of Radiology, Berlin (Germany); University of Munich - Grosshadern, Department of Clinical Radiology, Munich (Germany); Ebersberger, Hans U. [Heart Center Munich-Bogenhausen, Department of Cardiology and Intensive Care Medicine, Munich (Germany); Diederichs, Gerd; Hamm, Bernd [Charite - University Medicine Berlin, Department of Radiology, Berlin (Germany); Botnar, Rene M. [King' s College London, Division of Imaging Sciences and Biomedical Engineering, London (United Kingdom); Makowski, Marcus R. [Charite - University Medicine Berlin, Department of Radiology, Berlin (Germany); King' s College London, Division of Imaging Sciences and Biomedical Engineering, London (United Kingdom)

    2016-03-15

    Molecular imaging aims to improve the identification and characterization of pathological processes in vivo by visualizing the underlying biological mechanisms. Molecular imaging techniques are increasingly used to assess vascular inflammation, remodeling, cell migration, angioneogenesis and apoptosis. In cardiovascular diseases, molecular magnetic resonance imaging (MRI) offers new insights into the in vivo biology of pathological vessel wall processes of the coronary and carotid arteries and the aorta. This includes detection of early vascular changes preceding plaque development, visualization of unstable plaques and assessment of response to therapy. The current review focuses on recent developments in the field of molecular MRI to characterise different stages of atherosclerotic vessel wall disease. A variety of molecular MR-probes have been developed to improve the non-invasive detection and characterization of atherosclerotic plaques. Specifically targeted molecular probes allow for the visualization of key biological steps in the cascade leading to the development of arterial vessel wall lesions. Early detection of processes which lead to the development of atherosclerosis and the identification of vulnerable atherosclerotic plaques may enable the early assessment of response to therapy, improve therapy planning, foster the prevention of cardiovascular events and may open the door for the development of patient-specific treatment strategies. (orig.)

  11. Automated image segmentation and registration of vessel wall MRI for quantitative assessment of carotid artery vessel wall dimensions and plaque composition

    NARCIS (Netherlands)

    Klooster, Ronald van 't

    2014-01-01

    The main goal of this thesis was to develop methods for automated segmentation, registration and classification of the carotid artery vessel wall and plaque components using multi-sequence MR vessel wall images to assess atherosclerosis. First, a general introduction into atherosclerosis and

  12. Subclavian vein aneurysm secondary to a benign vessel wall hamartoma

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    Warren, Patrick [Nationwide Children' s Hospital, Section of Pediatric Interventional Radiology, Columbus, OH (United States); Spaeth, Maya [Nationwide Children' s Hospital, Section of Plastic and Reconstructive Surgery, Columbus, OH (United States); Prasad, Vinay [Nationwide Children' s Hospital, Section of Pediatric Pathology, Columbus, OH (United States); McConnell, Patrick [Nationwide Children' s Hospital, Section of Cardiothoracic Surgery, Columbus, OH (United States)

    2013-11-15

    Venous aneurysms are rare clinical entities, particularly in children, and their presentation and natural history often depend on the anatomical location and underlying etiology. We present a single case of a 12-year-old girl who presented with a palpable right supraclavicular mass. Imaging evaluation with CT, conventional venography, MRI and sonography revealed a large fusiform subclavian vein aneurysm with an unusual, mass-like fibrofatty component incorporated into the vessel wall. The girl ultimately required complete resection of the right subclavian vein with placement of a synthetic interposition graft. This case provides a radiology/pathology correlation of an entity that has not previously been described as well as an example of the utility of multiple imaging modalities to aid diagnosis and preoperative planning. (orig.)

  13. An Ultrasound Simulation Model for the Pulsatile Blood Flow Modulated by the Motion of Stenosed Vessel Wall.

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    Zhang, Qinghui; Zhang, Yufeng; Zhou, Yi; Zhang, Kun; Zhang, Kexin; Gao, Lian

    2016-01-01

    This paper presents an ultrasound simulation model for pulsatile blood flow, modulated by the motion of a stenosed vessel wall. It aims at generating more realistic ultrasonic signals to provide an environment for evaluating ultrasound signal processing and imaging and a framework for investigating the behaviors of blood flow field modulated by wall motion. This model takes into account fluid-structure interaction, blood pulsatility, stenosis of the vessel, and arterial wall movement caused by surrounding tissue's motion. The axial and radial velocity distributions of blood and the displacement of vessel wall are calculated by solving coupled Navier-Stokes and wall equations. With these obtained values, we made several different phantoms by treating blood and the vessel wall as a group of point scatterers. Then, ultrasound echoed signals from oscillating wall and blood in the axisymmetric stenotic-carotid arteries were computed by ultrasound simulation software, Field II. The results show better consistency with corresponding theoretical values and clinical data and reflect the influence of wall movement on the flow field. It can serve as an effective tool not only for investigating the behavior of blood flow field modulated by wall motion but also for quantitative or qualitative evaluation of new ultrasound imaging technology and estimation method of blood velocity.

  14. Effects of dynamic shear and transmural pressure on wall shear stress sensitivity in collecting lymphatic vessels.

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    Kornuta, Jeffrey A; Nepiyushchikh, Zhanna; Gasheva, Olga Y; Mukherjee, Anish; Zawieja, David C; Dixon, J Brandon

    2015-11-01

    Given the known mechanosensitivity of the lymphatic vasculature, we sought to investigate the effects of dynamic wall shear stress (WSS) on collecting lymphatic vessels while controlling for transmural pressure. Using a previously developed ex vivo lymphatic perfusion system (ELPS) capable of independently controlling both transaxial pressure gradient and average transmural pressure on an isolated lymphatic vessel, we imposed a multitude of flow conditions on rat thoracic ducts, while controlling for transmural pressure and measuring diameter changes. By gradually increasing the imposed flow through a vessel, we determined the WSS at which the vessel first shows sign of contraction inhibition, defining this point as the shear stress sensitivity of the vessel. The shear stress threshold that triggered a contractile response was significantly greater at a transmural pressure of 5 cmH2O (0.97 dyne/cm(2)) than at 3 cmH2O (0.64 dyne/cm(2)). While contraction frequency was reduced when a steady WSS was applied, this inhibition was reversed when the applied WSS oscillated, even though the mean wall shear stresses between the conditions were not significantly different. When the applied oscillatory WSS was large enough, flow itself synchronized the lymphatic contractions to the exact frequency of the applied waveform. Both transmural pressure and the rate of change of WSS have significant impacts on the contractile response of lymphatic vessels to flow. Specifically, time-varying shear stress can alter the inhibition of phasic contraction frequency and even coordinate contractions, providing evidence that dynamic shear could play an important role in the contractile function of collecting lymphatic vessels. Copyright © 2015 the American Physiological Society.

  15. In vivo and ex vivo vessel wall MRI of the circle of Willis

    NARCIS (Netherlands)

    Harteveld, A.A.|info:eu-repo/dai/nl/413650286

    2017-01-01

    In recent years, several MRI sequences have been developed for direct evaluation of the intracranial vessel wall and its pathology in vivo. These MRI sequences enable detection of intracranial vessel wall abnormalities, including those that have not yet caused luminal narrowing. The research field

  16. Gadolinium Enhanced MR Coronary Vessel Wall Imaging at 3.0 Tesla

    Directory of Open Access Journals (Sweden)

    Sebastian Kelle

    2010-01-01

    Full Text Available Purpose. We evaluated the influence of the time between low-dose gadolinium (Gd contrast administration and coronary vessel wall enhancement (LGE detected by 3T magnetic resonance imaging (MRI in healthy subjects and patients with coronary artery disease (CAD. Materials and Methods. Four healthy subjects (4 men, mean age 29  ±  3 years and eleven CAD patients (6 women, mean age 61±10 years were studied on a commercial 3.0 Tesla (T whole-body MR imaging system (Achieva 3.0 T; Philips, Best, The Netherlands. T1-weighted inversion-recovery coronary magnetic resonance imaging (MRI was repeated up to 75 minutes after administration of low-dose Gadolinium (Gd (0.1 mmol/kg Gd-DTPA. Results. LGE was seen in none of the healthy subjects, however in all of the CAD patients. In CAD patients, fifty-six of 62 (90.3% segments showed LGE of the coronary artery vessel wall at time-interval 1 after contrast. At time-interval 2, 34 of 42 (81.0% and at time-interval 3, 29 of 39 evaluable segments (74.4% were enhanced. Conclusion. In this work, we demonstrate LGE of the coronary artery vessel wall using 3.0 T MRI after a single, low-dose Gd contrast injection in CAD patients but not in healthy subjects. In the majority of the evaluated coronary segments in CAD patients, LGE of the coronary vessel wall was already detectable 30–45 minutes after administration of the contrast agent.

  17. "Sausage-string" appearance of arteries and arterioles can be caused by an instability of the blood vessel wall

    DEFF Research Database (Denmark)

    Jacobsen, Jens Christian Brings; Beierholm, Ulrik; Mikkelsen, Rene

    2002-01-01

    Vascular damage induced by acute hypertension is preceded by a peculiar pattern where blood vessels show alternating regions of constrictions and dilations ("sausages on a string"). The pattern occurs in the smaller blood vessels, and it plays a central role in causing the vascular damage....... A related vascular pattern has been observed in larger vessels from several organs during angiography. In the larger vessels the occurrence of the pattern does not appear to be related to acute hypertension. A unifying feature between the phenomenon in large and small vessels seems to be an increase...... observed experimentally. Most importantly, it suggests that the "sausaging" phenomenon is neither caused by a mechanical failure of the vessel wall due to a high blood pressure nor is it due to standing pressure waves caused by the beating of the heart. Rather, it is the expression of a general instability...

  18. Primary Metabolism during Biosynthesis of Secondary Wall Polymers of Protoxylem Vessel Elements.

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    Ohtani, Misato; Morisaki, Keiko; Sawada, Yuji; Sano, Ryosuke; Uy, Abigail Loren Tung; Yamamoto, Atsushi; Kurata, Tetsuya; Nakano, Yoshimi; Suzuki, Shiro; Matsuda, Mami; Hasunuma, Tomohisa; Hirai, Masami Yokota; Demura, Taku

    2016-11-01

    Xylem vessels, the water-conducting cells in vascular plants, undergo characteristic secondary wall deposition and programmed cell death. These processes are regulated by the VASCULAR-RELATED NAC-DOMAIN (VND) transcription factors. Here, to identify changes in metabolism that occur during protoxylem vessel element differentiation, we subjected tobacco (Nicotiana tabacum) BY-2 suspension culture cells carrying an inducible VND7 system to liquid chromatography-mass spectrometry-based wide-target metabolome analysis and transcriptome analysis. Time-course data for 128 metabolites showed dynamic changes in metabolites related to amino acid biosynthesis. The concentration of glyceraldehyde 3-phosphate, an important intermediate of the glycolysis pathway, immediately decreased in the initial stages of cell differentiation. As cell differentiation progressed, specific amino acids accumulated, including the shikimate-related amino acids and the translocatable nitrogen-rich amino acid arginine. Transcriptome data indicated that cell differentiation involved the active up-regulation of genes encoding the enzymes catalyzing fructose 6-phosphate biosynthesis from glyceraldehyde 3-phosphate, phosphoenolpyruvate biosynthesis from oxaloacetate, and phenylalanine biosynthesis, which includes shikimate pathway enzymes. Concomitantly, active changes in the amount of fructose 6-phosphate and phosphoenolpyruvate were detected during cell differentiation. Taken together, our results show that protoxylem vessel element differentiation is associated with changes in primary metabolism, which could facilitate the production of polysaccharides and lignin monomers and, thus, promote the formation of the secondary cell wall. Also, these metabolic shifts correlate with the active transcriptional regulation of specific enzyme genes. Therefore, our observations indicate that primary metabolism is actively regulated during protoxylem vessel element differentiation to alter the cell's metabolic

  19. Growth Description for Vessel Wall Adaptation: A Thick-Walled Mixture Model of Abdominal Aortic Aneurysm Evolution.

    Science.gov (United States)

    Grytsan, Andrii; Eriksson, Thomas S E; Watton, Paul N; Gasser, T Christian

    2017-08-25

    (1) Background: Vascular tissue seems to adapt towards stable homeostatic mechanical conditions, however, failure of reaching homeostasis may result in pathologies. Current vascular tissue adaptation models use many ad hoc assumptions, the implications of which are far from being fully understood; (2) Methods: The present study investigates the plausibility of different growth kinematics in modeling Abdominal Aortic Aneurysm (AAA) evolution in time. A structurally motivated constitutive description for the vessel wall is coupled to multi-constituent tissue growth descriptions; Constituent deposition preserved either the constituent's density or its volume, and Isotropic Volume Growth (IVG), in-Plane Volume Growth (PVG), in-Thickness Volume Growth (TVG) and No Volume Growth (NVG) describe the kinematics of the growing vessel wall. The sensitivity of key modeling parameters is explored, and predictions are assessed for their plausibility; (3) Results: AAA development based on TVG and NVG kinematics provided not only quantitatively, but also qualitatively different results compared to IVG and PVG kinematics. Specifically, for IVG and PVG kinematics, increasing collagen mass production accelerated AAA expansion which seems counterintuitive. In addition, TVG and NVG kinematics showed less sensitivity to the initial constituent volume fractions, than predictions based on IVG and PVG; (4) Conclusions: The choice of tissue growth kinematics is of crucial importance when modeling AAA growth. Much more interdisciplinary experimental work is required to develop and validate vascular tissue adaption models, before such models can be of any practical use.

  20. High-Resolution Vessel Wall Magnetic Resonance Imaging in Varicella-Zoster Virus Vasculitis.

    Science.gov (United States)

    Tsivgoulis, Georgios; Lachanis, Stefanos; Magoufis, Georgios; Safouris, Apostolos; Kargiotis, Odysseas; Stamboulis, Elefterios

    2016-06-01

    Varicella-zoster virus vasculopathy is a rare but potentially treatable condition. Diagnosis has been based on angiography, brain magnetic resonance imaging (MRI), and cerebrospinal fluid analysis. High-resolution vessel wall MRI may aid to the diagnosis by differentiating inflammation from other vessel wall pathologies. We present the characteristic MRI findings of this condition in a young patient presenting with ischemic stroke. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  1. [The exogenous and genetic components of some vessel wall characteristics in the pig (author's transl)].

    Science.gov (United States)

    Wegner, W

    1975-01-01

    Insufficiencies of the circulatory system and increasing transport losses in pigs as well as analogies with respect to atherosclerosis of men and swine were the motives for a broad statistical investigation of important characteristics of the circulatory system in a big population of female German landrace pigs, fattened as progeny groups under identical conditions in a testing station and slaughtered at 100 kg weight. As the most essential results, highly significant seasonal and genetical influences on several traits are to be mentioned, and some meaningful correlations between them: Plasma cholesterol, ceruloplasmin and hematocrit showed markedly lower levels in the summer and increased values in the cold season; the thickness of the intima (aorta and arteria pulmonalis) was quite distinctly greatest in the spring, this phenomenon being almost exactly paralleled by augmented amounts of copper and iron in the aortic wall. Increased heart weights were again found in the cold, decreased ones in the warm seasons. On average, bigger hearts and vessels were accompanied by higher elastin contents of the aorta, but these contents stood in very significant negative correlation to the ash content and the amounts of certain mineral components (Ca, Mg and P) of the vessel wall, especially to the ash percentage of the elastic fibers. This indicates that calcifying and mineralizing processes in the wall obviously take place at the cost of the elastic components. The estimation of heritabilities in half and full sibs revealed with h2 = 60% high henetic influences on the elastin content of the aorta and equally so on the ash percentage of elastic fibers. Future investigations must correlate these findings with direct measurements of biomechanical and rheological properties of the vessels.

  2. Carotid Intraplaque Hemorrhage Imaging with Quantitative Vessel Wall T1 Mapping: Technical Development and Initial Experience.

    Science.gov (United States)

    Qi, Haikun; Sun, Jie; Qiao, Huiyu; Chen, Shuo; Zhou, Zechen; Pan, Xinlei; Wang, Yishi; Zhao, Xihai; Li, Rui; Yuan, Chun; Chen, Huijun

    2017-11-08

    Purpose To develop a three-dimensional (3D) high-spatial-resolution time-efficient sequence for use in quantitative vessel wall T1 mapping. Materials and Methods A previously described sequence, simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) imaging, was extended by introducing 3D golden angle radial k-space sampling (GOAL-SNAP). Sliding window reconstruction was adopted to reconstruct images at different inversion delay times (different T1 contrasts) for voxelwise T1 fitting. Phantom studies were performed to test the accuracy of T1 mapping with GOAL-SNAP against a two-dimensional inversion recovery (IR) spin-echo (SE) sequence. In vivo studies were performed in six healthy volunteers (mean age, 27.8 years ± 3.0 [standard deviation]; age range, 24-32 years; five male) and five patients with atherosclerosis (mean age, 66.4 years ± 5.5; range, 60-73 years; five male) to compare T1 measurements between vessel wall sections (five per artery) with and without intraplaque hemorrhage (IPH). Statistical analyses included Pearson correlation coefficient, Bland-Altman analysis, and Wilcoxon rank-sum test with data permutation by subject. Results Phantom T1 measurements with GOAL-SNAP and IR SE sequences showed excellent correlation (R(2) = 0.99), with a mean bias of -25.8 msec ± 43.6 and a mean percentage error of 4.3% ± 2.5. Minimum T1 was significantly different between sections with IPH and those without it (mean, 371 msec ± 93 vs 944 msec ± 120; P = .01). Estimated T1 of normal vessel wall and muscle were 1195 msec ± 136 and 1117 msec ± 153, respectively. Conclusion High-spatial-resolution (0.8 mm isotropic) time-efficient (5 minutes) vessel wall T1 mapping is achieved by using the GOAL-SNAP sequence. This sequence may yield more quantitative reproducible biomarkers with which to characterize IPH and monitor its progression. (©) RSNA, 2017.

  3. Saccharomyces cerevisiae gene expression changes during rotating wall vessel suspension culture

    Science.gov (United States)

    Johanson, Kelly; Allen, Patricia L.; Lewis, Fawn; Cubano, Luis A.; Hyman, Linda E.; Hammond, Timothy G.

    2002-01-01

    This study utilizes Saccharomyces cerevisiae to study genetic responses to suspension culture. The suspension culture system used in this study is the high-aspect-ratio vessel, one type of the rotating wall vessel, that provides a high rate of gas exchange necessary for rapidly dividing cells. Cells were grown in the high-aspect-ratio vessel, and DNA microarray and metabolic analyses were used to determine the resulting changes in yeast gene expression. A significant number of genes were found to be up- or downregulated by at least twofold as a result of rotational growth. By using Gibbs promoter alignment, clusters of genes were examined for promoter elements mediating these genetic changes. Candidate binding motifs similar to the Rap1p binding site and the stress-responsive element were identified in the promoter regions of differentially regulated genes. This study shows that, as in higher order organisms, S. cerevisiae changes gene expression in response to rotational culture and also provides clues for investigations into the signaling pathways involved in gravitational response.

  4. Estrogen receptor expression and vessel density in the vagina wall in postmenopausal women with prolapse.

    Science.gov (United States)

    Lara, Lúcia Alves da Silva; Ribeiro da Silva, Alfredo; Rosa-e-Silva, Julio Cesar; Silva-de-Sá, Marcos Felipe; Rosa-e-Silva, Ana Carolina Japur de Sá

    2014-04-01

    After menopause, critically estrogen low levels result in modifications in vaginal wall. This cross-sectional study aims to determine whether there is a change in the number of vessels in the lamina propria of the vagina after menopause in parallel to the ER-alpha expression on the vaginal wall. Twelve women who underwent a genital surgery for genital prolapse up to grade II were selected. They were divided into two groups: a premenopausal group (PG) consisting of six women who were 18-40 years old with FSH levels =12 mIU/ml and regular cycles, and a menopausal group (MG) consisting of six women at least one year after menopause who were <65 years old with FSH levels =40 mIU/ml. Slides were stained for ER-alpha immunohistochemistry, and an endothelial cell marker CD3 was used to label vessels which were identified by using a system for morphometry. The number of vessels was significantly higher in the PG than in the MG both on the anterior wall (PG: 1.055 ± 145.8 vessels/mm(2), MG: 346.6 ± 209.9 vessels/mm(2), p<0.0001) and on the posterior wall (PG: 1064 ± 303.3 vessels/mm(2), MG: 348.6 ± 167.3 vessels/mm(2), p=0.0005). The ER-alpha score was significantly higher in the PG than the score for the MG on both the anterior and posterior walls (PG: 6.0 ± 0.52, MG: 2.5 ± 0.89, p=0.007; PG: 5.8 ± 0.79, MG: 2.7 ± 0.95, p=0.03, respectively). There was a positive correlation between the ER-alpha score and the vessel concentration on the anterior (r=0.6656, p=0.018) and posterior (r=0.6738, p=0.016) vaginal walls. Age was strongly negatively correlated with vessel concentration on the vaginal walls (respectively r=-0.9033, p<0.0001, r=-0.7440, p=0.0055). Therefore, postmenopausal women with genital prolapse have a smaller number of vessels on the vaginal wall compared to normoestrogenic controls with the same pathological condition. Hypoestrogenism and advancing age are factors that are associated to these changes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Atherosclerosis: contrast-enhanced MR imaging of vessel wall in rabbit model--comparison of gadofosveset and gadopentetate dimeglumine.

    Science.gov (United States)

    Lobbes, Marc B I; Miserus, Robbert-Jan J H M; Heeneman, Sylvia; Passos, Valeria Lima; Mutsaers, Peter H A; Debernardi, Nicola; Misselwitz, Bernd; Post, Mark; Daemen, Mat J A P; van Engelshoven, Jos M A; Leiner, Tim; Kooi, Marianne E

    2009-03-01

    To investigate the potential of gadofosveset for contrast material-enhanced magnetic resonance (MR) imaging of plaque in a rabbit model of atherosclerosis. All experiments were approved by the animal ethics committee. Thirty-one New Zealand White rabbits were included in one of four study groups: animals with atherosclerosis imaged with gadofosveset (n = 10) or gadopentetate dimeglumine (n = 7) and control animals imaged with gadofosveset (n = 7) or gadopentetate dimeglumine (n = 7). Aortic atherosclerosis was induced through endothelial denudation combined with a cholesterol-enriched diet. Control rabbits underwent a sham surgical procedure and received a regular diet. After 8 weeks, pre- and postcontrast T1-weighted MR images of the aortic vessel wall were acquired. Relative signal enhancement was determined with dedicated software. Statistical analysis was performed by using a generalized linear mixed model. Immunohistochemical staining with CD31 and albumin was used to assess microvessel density and the albumin content of the vascular wall. Group differences were analyzed by using a chi(2) test. Gadofosveset spatial distribution and content within the vessel wall were determined with proton-induced x-ray emission (PIXE) analysis. Postcontrast signal enhancement was significantly greater for atherosclerotic than for control animals imaged with gadofosveset (P = .022). Gadopentetate dimeglumine could not enable discrimination between normal and atherosclerotic vessel walls (P = .428). PIXE analysis showed higher amounts of gadopentetate dimeglumine than gadofosveset in both atherosclerotic and normal rabbit aortas. Immunohistochemical staining revealed the presence of albumin and increased microvessel density in the vascular walls of atherosclerotic rabbits. These results suggest that gadofosveset can be used to differentiate between atherosclerotic and normal rabbit vessel walls. http://radiology.rsnajnls.org/cgi/content/full/250/3/682/DC1. RSNA, 2009

  6. Histological study on the influences of an ultrasonic scalpel on skeletonized vessel wall.

    Science.gov (United States)

    Fukata, Yoshio; Horike, Kazuya; Kano, Masashi

    2002-10-01

    The objective of this study was to histologically clarify the difference of vascular wall damage when an ultrasonic scalpel is used in varied ways in the vicinity of a vessel. 1) The surface of sodium carbonate-containing jelly was manually brushed with the edge of a dissecting hook type Harmonic Scalpel (HS), and the thickness of the air bubble layer was measured to investigate the range to which the vibrations of the instrument reached. 2) The internal thoracic artery (ITA), radial artery (RA) and vein skeletonized were cut bluntly or brushed using HS ex vivo, and tissue damages were observed histologically. 3) The depth of thermal degeneration (TD) of residual stumps of ITAs skeletonized by HS using an output power level (level) of 2 and the quick touch method at the time of coronary arterial bypass grafting (CABG) were investigated histologically. 1) The mean thickness of the air bubble layers by single brushing was 3.7, 3.7 and 3.1 mm at level 4, 3 and 2, and no significant difference. When brushed 5 times, it was 6.9, 5.5 and 6.7 mm, respectively, showing marked increases compared with single brushing. 2) A: One side of the RA stump cut with a dissecting hook at level 2 was nicely occluded by a degenerated protein coagulum, but the contralateral had no coagulum. An ITA cut by a shear type blade at level 3 showed that both stumps were nicely occluded, but the vessel wall was introverted and fragmented. B: ITAs brushed 5 or 10 times at level 2 showed that TD occurred in tunica externa, the mean depth of 100 or 203 microm, and never exceeded the external elastic lamella. RAs brushed 10 times at level 2 and 3 showed that TD and air bubble generation occurred in the tunica externa, and the mean depth was 203 and 203 microm. However, TD exceeded the external lamella in some cases at level 3. Veins brushed 10 times at level 3 showed that TD spread to all layers. 3) The depth of TD in ITAs skeletonized clinically by HS was 400 to 530 microm, and apart from the

  7. Could the heat sink effect of blood flow inside large vessels protect the vessel wall from thermal damage during RF-assisted surgical resection?

    Science.gov (United States)

    González-Suárez, Ana; Trujillo, Macarena; Burdío, Fernando; Andaluz, Anna; Berjano, Enrique

    2014-08-01

    To assess by means of computer simulations whether the heat sink effect inside a large vessel (portal vein) could protect the vessel wall from thermal damage close to an internally cooled electrode during radiofrequency (RF)-assisted resection. First,in vivo experiments were conducted to validate the computational model by comparing the experimental and computational thermal lesion shapes created around the vessels. Computer simulations were then carried out to study the effect of different factors such as device-tissue contact, vessel position, and vessel-device distance on temperature distributions and thermal lesion shapes near a large vessel, specifically the portal vein. The geometries of thermal lesions around the vessels in the in vivo experiments were in agreement with the computer results. The thermal lesion shape created around the portal vein was significantly modified by the heat sink effect in all the cases considered. Thermal damage to the portal vein wall was inversely related to the vessel-device distance. It was also more pronounced when the device-tissue contact surface was reduced or when the vessel was parallel to the device or perpendicular to its distal end (blade zone), the vessel wall being damaged at distances less than 4.25 mm. The computational findings suggest that the heat sink effect could protect the portal vein wall for distances equal to or greater than 5 mm, regardless of its position and distance with respect to the RF-based device.

  8. Ex vivo blood vessel bioreactor for analysis of the biodegradation of magnesium stent models with and without vessel wall integration.

    Science.gov (United States)

    Wang, Juan; Liu, Lumei; Wu, Yifan; Maitz, Manfred F; Wang, Zhihong; Koo, Youngmi; Zhao, Ansha; Sankar, Jagannathan; Kong, Deling; Huang, Nan; Yun, Yeoheung

    2017-03-01

    Current in vitro models fail in predicting the degradation rate and mode of magnesium (Mg) stents in vivo. To overcome this, the microenvironment of the stent is simulated here in an ex vivo bioreactor with porcine aorta and circulating medium, and compared with standard static in vitro immersion and with in vivo rat aorta models. In ex vivo and in vivo conditions, pure Mg wires were exposed to the aortic lumen and inserted into the aortic wall to mimic early- and long-term implantation, respectively. Results showed that: 1) Degradation rates of Mg were similar for all the fluid diffusion conditions (in vitro static, aortic wall ex vivo and in vivo); however, Mg degradation under flow condition (i.e. in the lumen) in vivo was slower than ex vivo; 2) The corrosion mode in the samples can be mainly described as localized (in vitro), mixed localized and uniform (ex vivo), and uniform (in vivo); 3) Abundant degradation products (MgO/Mg(OH)2 and Ca/P) with gas bubbles accumulated around the localized degradation regions ex vivo, but a uniform and thin degradation product layer was found in vivo. It is concluded that the ex vivo vascular bioreactor provides an improved test setting for magnesium degradation between static immersion and animal experiments and highlights its promising role in bridging degradation behavior and biological response for vascular stent research. Magnesium and its alloys are candidates for a new generation of biodegradable stent materials. However, the in vitro degradation of magnesium stents does not match the clinical degradation rates, corrupting the validity of conventional degradation tests. Here we report an ex vivo vascular bioreactor, which allows simulation of the microenvironment with and without blood vessel integration to study the biodegradation of magnesium implants in comparison with standard in vitro test conditions and with in vivo implantations. The bioreactor did simulate the corrosion of an intramural implant very well, but

  9. Evaluation of acoustic emission signals during monitoring of thick-wall vessels operating at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Anastasopoulos, A.; Tsimogiannis, A. [Envirocoustics S.A., El. Venizelou 7 and Delfon, Athens (Greece)

    2004-07-01

    Acoustic Emission testing of thick wall vessels, operating at elevated temperatures is discussed and pattern recognition methodologies for AE data evaluation are presented. Two different types of testing procedures are addressed: Cool Down monitoring and semi-continuous periodic monitoring. In both types of tests, temperature variation is the driving force of AE as opposed to traditional AE testing where controlled pressure variation is used as AE stimulus. Representative examples of reactors cool down testing as well as in-process vessel monitoring are given. AE activity as a function of temperature and pressure variation is discussed. In addition to the real-time limited criteria application, unsupervised pattern recognition is applied as a post-processing tool for multidimensional sorting, noise discrimination, characterizing defects and/or damage. On the other hand, Supervised Pattern Recognition is used for data classification in repetitive critical tests, leading to an objective quantitative comparison between repeated tests. Results show that damage sustained by the equipment can be described by the plotting the cumulative energy of AE, from critical signal classes, versus temperature. Overall, the proposed methodology can reduce the complexity of AE tests in many cases leading to higher efficiency. The possibility for real time signals classification, during permanent AE installations and continuous monitoring is discussed. (orig.)

  10. Increased coronary vessel wall thickness in HIV-infected young adults.

    Science.gov (United States)

    Abd-Elmoniem, Khaled Z; Unsal, Aylin B; Eshera, Sarah; Matta, Jatin R; Muldoon, Nancy; McAreavey, Dorothea; Purdy, Julia B; Hazra, Rohan; Hadigan, Colleen; Gharib, Ahmed M

    2014-12-15

    Individuals with long-term human immunodeficiency virus (HIV) infection are at risk for premature vasculopathy and cardiovascular disease (CVD). We evaluated coronary vessel wall thickening, coronary plaque, and epicardial fat in patients infected with HIV early in life compared with healthy controls. This is a prospective cross-sectional study of 35 young adults who acquired HIV in early life and 11 healthy controls, free of CVD. Time resolved phase-sensitive dual inversion recovery black-blood vessel wall magnetic resonance imaging (TRAPD) was used to measure proximal right coronary artery (RCA) wall thickness, and multidetector computed tomography (CT) angiography was used to quantify coronary plaque and epicardial fat. RCA vessel wall thickness was significantly increased in HIV-infected patients compared with sex- and race-matched controls (1.32 ± 0.21 mm vs 1.09 ± 0.14 mm, P = .002). No subject had discrete plaque on CT sufficient to cause luminal narrowing, and plaque was not related to RCA wall thickness. In multivariate regression analyses, smoking pack-years (P = .004) and HIV infection (P = .007) were independently associated with thicker RCA vessel walls. Epicardial fat did not differ between groups. Among the HIV-infected group, duration of antiretroviral therapy (ART) (P = .02), duration of stavudine exposure (P ART, hyperlipidemia, and smoking contributed to proximal RCA thickening, independent of atherosclerotic plaque quantified by CT. These modifiable risk factors appear to influence early atherogenesis as measured by coronary wall thickness and may be important targets for CVD risk reduction. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  11. Coronary magnetic resonance angiography and vessel wall imaging in children with Kawasaki disease

    Energy Technology Data Exchange (ETDEWEB)

    Greil, Gerald F.; Hofbeck, Michael; Sieverding, Ludger [University of Tuebingen, Department of Pediatric Cardiology, Children' s Hospital, Tuebingen (Germany); Seeger, Achim; Miller, Stephan; Claussen, Claus D. [University of Tuebingen, Department of Diagnostic Radiology, Tuebingen (Germany); Botnar, Rene M. [Technical University Munich, Department of Nuclear Medicine, Cardiovascular Division, Munich (Germany)

    2007-07-15

    In patients with Kawasaki disease (KD) serial evaluation of the distribution and size of coronary artery aneurysms (CAA) is necessary for risk stratification and therapeutic management. To apply whole-heart coronary MR angiography (CMRA) and black-blood coronary vessel wall imaging in children with KD. Six children (mean age 4.6 years, range 2.5-7.8 years) with KD underwent CMRA using a free-breathing, T2-prepared, three-dimensional steady-state free-precession (3D-SSFP), whole-heart approach with navigator gating and tracking. Vessel walls were imaged with an ECG-triggered and navigator-gated double inversion recovery (DIR) black-blood segmented turbo spin-echo sequence. There was complete agreement between CMRA and conventional angiography (n=6) in the detection of CAA (n=15). Excellent agreement was found between the two techniques in determining the maximal diameter (mean difference 0.2{+-}0.7 mm), length (mean difference 0.1{+-}0.8 mm) and distance from the ostium (mean difference -0.8{+-}2.1 mm) of the CAAs. In all subjects with a CAA, abnormally thickened vessel walls were found (2.5{+-}0.5 mm). CMRA accurately defines CAA in free-breathing sedated children with KD using the whole-heart approach and detects abnormally thickened vessel walls. This technique may reduce the need for serial X-ray coronary angiography, and improve risk stratification and monitoring of therapy. (orig.)

  12. Learning-based automated segmentation of the carotid artery vessel wall in dual-sequence MRI using subdivision surface fitting

    NARCIS (Netherlands)

    Gao, Shan; van't Klooster, Ronald; Kitslaar, Pieter H.; Coolen, Bram F.; van den Berg, Alexandra M.; Smits, Loek P.; Shahzad, Rahil; Shamonin, Denis P.; de Koning, Patrick J. H.; Nederveen, Aart J.; van der Geest, Rob J.

    2017-01-01

    Purpose: The quantification of vessel wall morphology and plaque burden requires vessel segmentation, which is generally performed by manual delineations. The purpose of our work is to develop and evaluate a new 3D model-based approach for carotid artery wall segmentation from dual-sequence MRI.

  13. Influence of acquired obesity on coronary vessel wall late gadolinium enhancement in discordant monozygote twins

    Energy Technology Data Exchange (ETDEWEB)

    Makowski, Marcus R. [King' s College London, Division of Imaging Sciences and Biomedical Engineering, London (United Kingdom); Wellcome Trust and EPSRC Medical Engineering Centre, London (United Kingdom); King' s College London, BHF Centre of Excellence, London (United Kingdom); King' s College London, NIHR Biomedical Research Centre, London (United Kingdom); Charite-Universitaetsmedizin, Department of Radiology, Berlin (Germany); Jansen, Christian H.P. [King' s College London, Division of Imaging Sciences and Biomedical Engineering, London (United Kingdom); Ebersberger, Ullrich; Spector, Tim D. [Heart Center Munich-Bogenhausen, Department of Cardiology and Intensive Care Medicine, Munich (Germany); Schaeffter, Tobias; Razavi, Reza [King' s College London, Division of Imaging Sciences and Biomedical Engineering, London (United Kingdom); Wellcome Trust and EPSRC Medical Engineering Centre, London (United Kingdom); King' s College London, BHF Centre of Excellence, London (United Kingdom); King' s College London, NIHR Biomedical Research Centre, London (United Kingdom); Mangino, Massimo [King' s College London, Department of Twin Research and Genetic Epidemiology, London (United Kingdom); National Institute for Health Research (NIHR) Biomedical Research Centre at Guy' s and St. Thomas' Foundation Trust, London (United Kingdom); Botnar, Rene M. [King' s College London, Division of Imaging Sciences and Biomedical Engineering, London (United Kingdom); Wellcome Trust and EPSRC Medical Engineering Centre, London (United Kingdom); King' s College London, BHF Centre of Excellence, London (United Kingdom); King' s College London, NIHR Biomedical Research Centre, London (United Kingdom); Greil, Gerald F. [King' s College London, Division of Imaging Sciences and Biomedical Engineering, London (United Kingdom); Wellcome Trust and EPSRC Medical Engineering Centre, London (United Kingdom); King' s College London, BHF Centre of Excellence, London (United Kingdom); King' s College London, NIHR Biomedical Research Centre, London (United Kingdom)

    2017-11-15

    The aim of this study was to investigate the impact of BMI on late gadolinium enhancement (LGE) of the coronary artery wall in identical monozygous twins discordant for BMI. Coronary LGE represents a useful parameter for the detection and quantification of atherosclerotic coronary vessel wall disease. Thirteen monozygote female twin pairs (n = 26) with significantly different BMIs (>1.6 kg/m2) were recruited out of >10,000 twin pairs (TwinsUK Registry). A coronary 3D-T2prep-TFE MR angiogram and 3D-IR-TFE vessel wall scan were performed prior to and following the administration of 0.2 mmol/kg of Gd-DTPA on a 1.5 T MR scanner. The number of enhancing coronary segments and contrast to noise ratios (CNRs) of the coronary wall were quantified. An increase in BMI was associated with an increased number of enhancing coronary segments (5.3 ± 1.5 vs. 3.5 ± 1.6, p < 0.0001) and increased coronary wall enhancement (6.1 ± 1.1 vs. 4.8 ± 0.9, p = 0.0027) compared to matched twins with lower BMI. This study in monozygous twins indicates that acquired factors predisposing to obesity, including lifestyle and environmental factors, result in increased LGE of the coronary arteries, potentially reflecting an increase in coronary atherosclerosis in this female study population. (orig.)

  14. Nanoparticle motion near a blood vessel wall in targeted drug delivery

    Science.gov (United States)

    Vitoshkin, Helena; Yu, Hsiu-Yu; Eckmann, David M.; Radhakrishnan, Ravi; Ayyaswamy, Portonovo S.

    2014-11-01

    A computational study of the motion of a spherical nanoparticle close to the bounding wall of a blood vessel in targeted drug delivery is presented. An arbitrary Lagrangian-Eulerian algorithm has been carried out, taking into account both the Brownian and the hydrodynamic effects. Pertinent to targeted drug delivery, we focus on the condition when the particle is in the lubrication layer. The velocity auto-correlation function (VACF) is seen to initially decay faster by a factor of particle radius divided by the fluid gap thickness compared to that in an unbounded medium. Long time decay is found to be algebraic. Focusing on hydrodynamic interaction between the particle and the wall, effects of wall curvature, particle size, and variations in density of the particle are investigated. We also study adhesive interactions of a nanoparticle with an endothelial cell located on the vessel wall by the modeling the nanoparticle tethered by a harmonic spring with varying spring constants. It is shown that the particle velocity is affected by hydrodynamic and harmonic spring forces leading to VACF oscillations which decay algebraically at long times. The results agree with those predicted by earlier theories for particle VACF near a wall. These findings have applications in medication administration and in the colloidal sciences. Supported by NIH Grant U01 EB016027.

  15. Distribution and natural course of intracranial vessel wall lesions in patients with ischemic stroke or TIA at 7.0 tesla MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kolk, Anja G. van der; Luijten, Peter R.; Hendrikse, Jeroen [University Medical Center Utrecht, Department of Radiology, Postbox 85500, Utrecht (Netherlands); Zwanenburg, Jaco J.M. [University Medical Center Utrecht, Department of Radiology, Postbox 85500, Utrecht (Netherlands); University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands); Brundel, Manon; Biessels, Geert Jan [University Medical Center Utrecht, Department of Neurology, Utrecht (Netherlands); Visser, Fredy [University Medical Center Utrecht, Department of Radiology, Postbox 85500, Utrecht (Netherlands); Philips Healthcare, Best (Netherlands)

    2015-06-01

    Previous studies using intracranial vessel wall MRI techniques showed that over 50 % of patients with ischemic stroke or TIA had one or more intracranial vessel wall lesions. In the current study, we assessed the preferential location of these lesions within the intracranial arterial tree and their potential changes over time in these patient groups. Forty-nine patients with ischemic stroke (n = 25) or TIA (n = 24) of the anterior cerebral circulation underwent 7.0 T MRI, including a T{sub 1}-weighted magnetization-preparation inversion recovery turbo-spin-echo (MPIR-TSE) sequence within one week and approximately one month after symptom onset. Intracranial vessel wall lesions were scored for multiple locations within the arterial tree and differences between one-week and one-month images. At baseline, 132 intracranial vessel wall lesions were found in 41 patients (84 %), located primarily in the anterior cerebral circulation (74 %), with a preferential location in the distal internal carotid artery and M1 and M2 segments of the middle cerebral artery. During follow-up, presence or enhancement patterns changed in 14 lesions (17 %). A large burden of intracranial vessel wall lesions was found in both the anterior and posterior cerebral circulation. Most lesions were found to be relatively stable, possibly indicating a more generalized atherosclerotic process. (orig.)

  16. Human elastic cartilage engineering from cartilage progenitor cells using rotating wall vessel bioreactor.

    Science.gov (United States)

    Takebe, T; Kobayashi, S; Kan, H; Suzuki, H; Yabuki, Y; Mizuno, M; Adegawa, T; Yoshioka, T; Tanaka, J; Maegawa, J; Taniguchi, H

    2012-05-01

    Transplantation of bioengineered elastic cartilage is considered to be a promising approach for patients with craniofacial defects. We have previously shown that human ear perichondrium harbors a population of cartilage progenitor cells (CPCs). The aim of this study was to examine the use of a rotating wall vessel (RWV) bioreactor for CPCs to engineer 3-D elastic cartilage in vitro. Human CPCs isolated from ear perichondrium were expanded and differentiated into chondrocytes under 2-D culture conditions. Fully differentiated CPCs were seeded into recently developed pC-HAp/ChS (porous material consisted of collagen, hydroxyapatite, and chondroitinsulfate) scaffolds and 3-D cultivated utilizing a RWV bioreactor. 3-D engineered constructs appeared shiny with a yellowish, cartilage-like morphology. The shape of the molded scaffold was maintained after RWV cultivation. Hematoxylin and eosin staining showed engraftment of CPCs inside pC-HAp/ChS. Alcian blue and Elastica Van Gieson staining showed of proteoglycan and elastic fibers, which are unique extracellular matrices of elastic cartilage. Thus, human CPCs formed elastic cartilage-like tissue after 3-D cultivation in a RWV bioreactor. These techniques may assist future efforts to reconstruct complicate structures composed of elastic cartilage in vitro. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. HIV-1 and recombinant gp120 affect the survival and differentiation of human vessel wall-derived mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Pasquinelli Gianandrea

    2011-05-01

    Full Text Available Abstract Background HIV infection elicits the onset of a progressive immunodeficiency and also damages several other organs and tissues such as the CNS, kidney, heart, blood vessels, adipose tissue and bone. In particular, HIV infection has been related to an increased incidence of cardiovascular diseases and derangement in the structure of blood vessels in the absence of classical risk factors. The recent characterization of multipotent mesenchymal cells in the vascular wall, involved in regulating cellular homeostasis, suggests that these cells may be considered a target of HIV pathogenesis. This paper investigated the interaction between HIV-1 and vascular wall resident human mesenchymal stem cells (MSCs. Results MSCs were challenged with classical R5 and X4 HIV-1 laboratory strains demonstrating that these strains are able to enter and integrate their retro-transcribed proviral DNA in the host cell genome. Subsequent experiments indicated that HIV-1 strains and recombinant gp120 elicited a reliable increase in apoptosis in sub-confluent MSCs. Since vascular wall MSCs are multipotent cells that may be differentiated towards several cell lineages, we challenged HIV-1 strains and gp120 on MSCs differentiated to adipogenesis and endotheliogenesis. Our experiments showed that the adipogenesis is increased especially by upregulated PPARγ activity whereas the endothelial differentiation induced by VEGF treatment was impaired with a downregulation of endothelial markers such as vWF, Flt-1 and KDR expression. These viral effects in MSC survival and adipogenic or endothelial differentiation were tackled by CD4 blockade suggesting an important role of CD4/gp120 interaction in this context. Conclusions The HIV-related derangement of MSC survival and differentiation may suggest a direct role of HIV infection and gp120 in impaired vessel homeostasis and in genesis of vessel damage observed in HIV-infected patients.

  18. Failure to show decrease in small pulmonary blood vessels in rats with experimental pulmonary hypertension.

    OpenAIRE

    Kay, J M; Suyama, K L; Keane, P M

    1982-01-01

    We induced chronic pulmonary hypertension in one group of rats by exposing them to chronic hypobaric hypoxia (380 mm Hg for three weeks) and in another group by administering a single subcutaneous dose of monocrotaline (60 mg/kg body weight). Both groups of rats showed increase of the right ventricular mean systolic blood pressure and right ventricular hypertrophy. We measured the surface area of histological sections of the left or right lungs and counted all small blood vessels with an exte...

  19. Conditioning of the vacuum vessel walls of tokamaks, a preliminary look

    Energy Technology Data Exchange (ETDEWEB)

    Sink, D.A.

    1976-03-01

    The main features and operating characteristics of the primary vacuum system of many of the presently operating tokamak devices are presented. Particular attention is paid to the methods used to condition and clean the vessel walls in situ. For the devices discussed, a combination of a high-temperature bakeout and/or discharge cleaning is employed. In addition, discussions of the vacuum systems and wall conditioning methods anticipated for the next generation of tokamaks are presented. Since this report was written during a limited time period, it should be considered as preliminary and is not intended to be a general review. Much of the information that is presented was obtained by private communication and there is no bibliography. This study was initiated to aid in the design of TFTR. As presently envisioned, the TFTR vacuum system and methods for wall conditioning are consistent with what is presently practiced.

  20. Quantification and Statistical Analysis Methods for Vessel Wall Components from Stained Images with Masson's Trichrome: e0146954

    National Research Council Canada - National Science Library

    Pablo Hernández-Morera; Irene Castaño-González; Carlos M Travieso-González; Blanca Mompeó-Corredera; Francisco Ortega-Santana

    2016-01-01

    ... (smooth muscle fibers and extracellular matrix) in the vessel wall stained with Masson's trichrome, and a statistical method suitable for small sample sizes to analyze the results previously obtained...

  1. Recording of unexpectedly high frequency vibrations of blood vessel walls in experimental arteriovenous fistulae of rabbits using a laser vibrometer.

    Science.gov (United States)

    Stehbens, W E; Liepsch, D W; Poll, A; Erhardt, W

    1995-01-01

    Because arteriovenous fistulae are associated with a palpable thrill and an audible murmur, the vibrational activity of the blood vessel walls about experimental arteriovenous fistulae in rabbits was investigated using, for the first time, a high-resolution laser vibrometer. Frequencies of mural vibrations up to 2200 Hz were recorded at different sites about the fistulae. The relationship of this vibratory activity of blood vessel walls to physiological and pathological conditions warrants further investigation.

  2. A completely noninvasive method of dissolved oxygen monitoring in disposable small-scale cell culture vessels based on diffusion through permeable vessel walls.

    Science.gov (United States)

    Gupta, Priyanka A; Ge, Xudong; Kostov, Yordan; Rao, Govind

    2014-01-01

    Disposable cell culture vessels are extensively used at small scales for process optimization and validation, but they lack monitoring capabilities. Optical sensors that can be easily adapted for use in small-scale vessels are commercially available for pH, dissolved oxygen (DO), and dissolved carbon dioxide (DCO2 ). However, their use has been limited due to the contamination and compatibility issues. We have developed a novel solution to these problems for DO monitoring. Oxygen diffusion through permeable vessel wall can be exploited for noninvasive monitoring. An optical oxygen sensor can be placed outside the oxygen permeable vessel wall thereby allowing oxygen diffusing through the vessel wall to be detected by the sensor. This way the sensor stays separate from the cell culture and there are no concerns about contaminants or leachants. Here we implement this method for two cell culture devices: polystyrene-made T-75 tissue culture flask and fluorinated ethylene propylene (FEP)-made Vuelife(®) cell culture bag. Additionally, mammalian and microbial cell cultures were performed in Vuelife(®) cell culture bags, proving that a sensor placed outside can be used to track changes in cell cultures. This approach toward noninvasive monitoring will help in integrating cell culture vessels with sensors in a seamless manner. © 2013 American Institute of Chemical Engineers.

  3. Upper and Lower Bound Limit Loads for Thin-Walled Pressure Vessels Used for Aerosol Cans

    Directory of Open Access Journals (Sweden)

    Stephen John Hardy

    2009-01-01

    Full Text Available The elastic compensation method proposed by Mackenzie and Boyle is used to estimate the upper and lower bound limit (collapse loads for one-piece aluminium aerosol cans, which are thin-walled pressure vessels subjected to internal pressure loading. Elastic-plastic finite element predictions for yield and collapse pressures are found using axisymmetric models. However, it is shown that predictions for the elastic-plastic buckling of the vessel base require the use of a full three-dimensional model with a small unsymmetrical imperfection introduced. The finite element predictions for the internal pressure to cause complete failure via collapse fall within the upper and lower bounds. Hence the method, which involves only elastic analyses, can be used in place of complex elastic-plastic finite element analyses when upper and lower bound estimates are adequate for design purposes. Similarly, the lower bound value underpredicts the pressure at which first yield occurs.

  4. Lymphocyte trafficking and HIV infection of human lymphoid tissue in a rotating wall vessel bioreactor

    Science.gov (United States)

    Margolis, L. B.; Fitzgerald, W.; Glushakova, S.; Hatfill, S.; Amichay, N.; Baibakov, B.; Zimmerberg, J.

    1997-01-01

    The pathogenesis of HIV infection involves a complex interplay between both the infected and noninfected cells of human lymphoid tissue, the release of free viral particles, the de novo infection of cells, and the recirculatory trafficking of peripheral blood lymphocytes. To develop an in vitro model for studying these various aspects of HIV pathogenesis we have utilized blocks of surgically excised human tonsils and a rotating wall vessel (RWV) cell culture system. Here we show that (1) fragments of the surgically excised human lymphoid tissue remain viable and retain their gross cytoarchitecture for at least 3 weeks when cultured in the RWV system; (2) such lymphoid tissue gradually shows a loss of both T and B cells to the surrounding growth medium; however, this cellular migration is reversible as demonstrated by repopulation of the tissue by labeled cells from the growth medium; (3) this cellular migration may be partially or completely inhibited by embedding the blocks of lymphoid tissue in either a collagen or agarose gel matrix; these embedded tissue blocks retain most of the basic elements of a normal lymphoid cytoarchitecture; and (4) both embedded and nonembedded RWV-cultured blocks of human lymphoid tissue are capable of productive infection by HIV-1 of at least three various strains of different tropism and phenotype, as shown by an increase in both p24 antigen levels and free virus in the culture medium, and by the demonstration of HIV-1 RNA-positive cells inside the tissue identified by in situ hybridization. It is therefore reasonable to suggest that gel-embedded and nonembedded blocks of human lymphoid tissue, cocultured with a suspension of tonsillar lymphocytes in an RWV culture system, constitute a useful model for simulating normal lymphocyte recirculatory traffic and provide a new tool for testing the various aspects of HIV pathogenesis.

  5. Association between proximal internal carotid artery steno-occlusive disease and diffuse wall thickening in its petrous segment: a magnetic resonance vessel wall imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaoyi; Li, Dongye [Capital Medical University and Beijing Institute for Brain Disorders, Center for Brain Disorders Research, Beijing (China); Tsinghua University School of Medicine, Center for Biomedical Imaging Research, Department of Biomedical Engineering, Beijing (China); Zhao, Huilin [Shanghai Jiao Tong University, Department of Radiology, Renji Hospital, School of Medicine, Shanghai (China); Chen, Zhensen; Qiao, Huiyu; He, Le; Li, Rui [Tsinghua University School of Medicine, Center for Biomedical Imaging Research, Department of Biomedical Engineering, Beijing (China); Cui, Yuanyuan [PLA General Hospital, Department of Radiology, Beijing (China); Zhou, Zechen [Philips Research China, Healthcare Department, Beijing (China); Yuan, Chun [Tsinghua University School of Medicine, Center for Biomedical Imaging Research, Department of Biomedical Engineering, Beijing (China); University of Washington, Department of Radiology, Seattle, WA (United States); Zhao, Xihai [Tsinghua University School of Medicine, Center for Biomedical Imaging Research, Department of Biomedical Engineering, Beijing (China); Beijing Institute for Brain Disorders, Center for Stroke, Beijing (China)

    2017-05-15

    Significant stenosis or occlusion in carotid arteries may lead to diffuse wall thickening (DWT) in the arterial wall of downstream. This study aimed to investigate the correlation between proximal internal carotid artery (ICA) steno-occlusive disease and DWT in ipsilateral petrous ICA. Symptomatic patients with atherosclerotic stenosis (>0%) in proximal ICA were recruited and underwent carotid MR vessel wall imaging. The 3D motion sensitized-driven equilibrium prepared rapid gradient-echo (3D-MERGE) was acquired for characterizing the wall thickness and longitudinal extent of the lesions in petrous ICA and the distance from proximal lesion to the petrous ICA. The stenosis degree in proximal ICA was measured on the time-of-flight (TOF) images. In total, 166 carotid arteries from 125 patients (mean age 61.0 ± 10.5 years, 99 males) were eligible for final analysis and 64 showed DWT in petrous ICAs. The prevalence of severe DWT in petrous ICA was 1.4%, 5.3%, 5.9%, and 80.4% in ipsilateral proximal ICAs with stenosis category of 1%-49%, 50%-69%, 70%-99%, and total occlusion, respectively. Proximal ICA stenosis was significantly correlated with the wall thickness in petrous ICA (r = 0.767, P < 0.001). Logistic regression analysis showed that proximal ICA stenosis was independently associated with DWT in ipsilateral petrous ICA (odds ratio (OR) = 2.459, 95% confidence interval (CI) 1.896-3.189, P < 0.001). Proximal ICA steno-occlusive disease is independently associated with DWT in ipsilateral petrous ICA. (orig.)

  6. Remote through-wall sampling of the Trawsfynydd reactor pressure vessel: an overview

    Energy Technology Data Exchange (ETDEWEB)

    Curry, A.; Clayton, R. [Magnox Electric, Berkeley (United Kingdom)

    1997-02-01

    This paper summarizes the application of robotic equipment for gaining access to, and removing through-wall samples, from, welds of the reactor pressure vessel at Trawsfyndd power station. The environment, which presents hazards due to ionising radiation, radioactive contamination and asbestos-bearing materials is described. The means of access, by use of remote vehicles with robotic manipulators supported by additional vehicles, it reviewed. The use of abrasive water jet cutting for sample removal is introduced. The relative advantages and disadvantages of this technique are discussed. (Author).

  7. Remote through-wall sampling of the Trawsfynydd reactor pressure vessel: an overview

    Energy Technology Data Exchange (ETDEWEB)

    Curry, A.; Clayton, R. [Magnox Electric, Dartford (United Kingdom). Remote Operations

    1996-12-31

    This paper summarises the application of robotic equipment for gaining access to and removing through-wall samples from welds of the reactor pressure vessel at Trawsfynydd power station. The environment, which presents hazards due to ionising radiation, radioactive contamination and asbestos bearing materials is described. The means of access, by use of remote vehicles complete with robotic manipulators supported by additional vehicles, is reviewed. The use of Abrasive Water Jet Cutting for sample removal is introduced. The relative advantages and disadvantages of this technique are discussed. (UK).

  8. Estimation of the radial force on the tokamak vessel wall during fast transient events

    Energy Technology Data Exchange (ETDEWEB)

    Pustovitov, V. D., E-mail: pustovitov-vd@nrcki.ru [National Research Center Kurchatov Institute (Russian Federation)

    2016-11-15

    The radial force balance in a tokamak during fast transient events with a duration much shorter than the resistive time of the vacuum vessel wall is analyzed. The aim of the work is to analytically estimate the resulting integral radial force on the wall. In contrast to the preceding study [Plasma Phys. Rep. 41, 952 (2015)], where a similar problem was considered for thermal quench, simultaneous changes in the profiles and values of the pressure and plasma current are allowed here. Thereby, the current quench and various methods of disruption mitigation used in the existing tokamaks and considered for future applications are also covered. General formulas for the force at an arbitrary sequence or combination of events are derived, and estimates for the standard tokamak model are made. The earlier results and conclusions are confirmed, and it is shown that, in the disruption mitigation scenarios accepted for ITER, the radial forces can be as high as in uncontrolled disruptions.

  9. A simulation environment for validating ultrasonic blood flow and vessel wall imaging based on fluid-structure interaction simulations: ultrasonic assessment of arterial distension and wall shear rate.

    Science.gov (United States)

    Swillens, Abigail; Degroote, Joris; Vierendeels, Jan; Lovstakken, Lasse; Segers, Patrick

    2010-08-01

    Ultrasound (US) is a commonly used vascular imaging tool when screening for patients at high cardiovascular risk. However, current blood flow and vessel wall imaging methods are hampered by several limitations. When optimizing and developing new ultrasound modalities, proper validation is required before clinical implementation. Therefore, the authors present a simulation environment integrating ultrasound and fluid-structure interaction (FSI) simulations, allowing construction of synthetic ultrasound images based on physiologically realistic behavior of an artery. To demonstrate the potential of the model for vascular ultrasound research, the authors studied clinically relevant imaging modalities of arterial function related to both vessel wall deformation and arterial hemodynamics: Arterial distension (related to arterial stiffness) and wall shear rate (related to the development of atherosclerosis) imaging. An in-house code ("TANGO") was developed to strongly couple the flow solver FLUENT and structural solver ABAQUS using an interface quasi-Newton technique. FIELD II was used to model realistic transducer and scan settings. The input to the FSI-US model is a scatterer phantom on which the US waves reflect, with the scatterer displacement derived from the FSI flow and displacement fields. The authors applied the simulation tool to a 3D straight tube, representative of the common carotid artery (length: 5 cm; and inner and outer radius: 3 and 4 mm). A mass flow inlet boundary condition, based on flow measured in a healthy subject, was applied. A downstream pressure condition, based on a noninvasively measured pressure waveform, was chosen and scaled to simulate three different degrees of arterial distension (1%, 4%, and 9%). The RF data from the FSI-US coupling were further processed for arterial wall and flow imaging. Using an available wall tracking algorithm, arterial distensibility was assessed. Using an autocorrelation estimator, blood velocity and shear

  10. Segmentation of elastic fibres in images of vessel wall sections stained with Weigert's resorcin-fuchsin.

    Science.gov (United States)

    Hernández-Morera, Pablo; Travieso-González, Carlos M; Castaño-González, Irene; Mompeó-Corredera, Blanca; Ortega-Santana, Francisco

    2017-04-01

    The elastic fibres are an essential component of the extracellular matrix in blood vessel walls that allows a long-range of deformability and passive recoil without energy input. The quantitative determination of elastic fibres will provide information on the state of the vascular wall and to determine the role and behaviour of this key structural element in different physiological and pathological vascular processes. We present a segmentation method to identify and quantify elastic fibres based on a local threshold technique and some morphological characteristics measured on the segmented objects that facilitate the discrimination between elastic fibres and other image components. The morphological characteristics analysed are the thickness and the length of an object. The segmentation method was evaluated using an image database of vein sections stained with Weigert's resorcin-fuchsin. The performance results are based on a ground truth generated manually resulting in values of sensitivity greater than 80% with the exception in two samples, and specificity values above 90% for all samples. Medical specialists carried out a visual evaluation where the observations indicate a general agreement on the segmentation results' visual quality, and the consistency between the methodology proposed and the subjective observation of the doctors for the evaluation of pathological changes in vessel wall. The proposed methodology provides more objective measurements than the qualitative methods traditionally used in the histological analysis, with a significant potential for this method to be used as a diagnostic aid for many other vascular pathological conditions and in similar tissues such as skin and mucous membranes. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Dynamic vessel wall properties and their reproducibility in subjects with increased cardiovascular risk.

    Science.gov (United States)

    van den Berkmortel, F; Wollersheim, H; van Langen, H; Thien, T

    1998-06-01

    To determine reproducibility figures of dynamic arterial wall properties such as cross-sectional compliance (CC) and distensibility (DC) in subjects with increased cardiovascular risk, in comparison with healthy adults. A total of 34 persons were divided into three groups with varying cardiovascular risk factors. Diameters (D) and diameter changes (deltaD) during the heart cycle of both common carotid (CCA) and right common femoral (CFA) arteries were measured by a vessel wall movement detector system. Blood pressures (BP) were recorded non-invasively by a semi-automated oscillometric device. CC (=piD(deltaD/2deltaP) in unit mm2/kPa) and DC (=2deltaD/D)/deltaP in unit 10(-3)/kPa) were calculated from the above-mentioned parameters. Measurements were performed twice during one visit and twice again with a time interval of at least 3 days to determine intra-observer intra- and intersession variability. Reproducibility figures of CC and DC of the CCA varied between 8 and 12%, and between 13 and 22% for the CFA. Intra-observer intra- and intersession variability were similar in the three groups. In our studies the reproducibility of dynamic vascular wall properties determined by ultrasound was good. Despite differences in the absolute values for CC and DC in groups with increased cardiovascular risk, mean reproducibility figures remained at a similar level (8-12%) as in healthy volunteers.

  12. Intra-specific trends of lumen and wall resistivities of vessels within the stem xylem vary among three woody plants.

    Science.gov (United States)

    Ooeda, Hiroki; Terashima, Ichiro; Taneda, Haruhiko

    2018-02-01

    Water flow through xylem vessels encounters hydraulic resistance when passing through the vessel lumen and end wall. Comparative studies have reported that lumen and end wall resistivities co-limit water flow through stem xylem in several angiosperm woody species that have vessels of different average diameter and length. This study examined the intra-specific relationship between the lumen and end wall resistivities (Rlumen and Rwall) for vessels within the stem xylem using three deciduous angiosperm woody species found in temperate forest. Morus australis Poir. and Acer rufinerve Siebold et Zucc. are early- and late-successional species, and Vitis coignetiae Pulliat ex Planch is a woody liana. According to the Hagen-Poiseuille equation, Rlumen is proportional to the fourth power of vessel diameter (D), whereas vessel length (L) and inter-vessel pit area (Apit) determine Rwall. To estimate Rlumen and Rwall, the scaling relationships between the L and D and between Apit and D were measured. The scaling exponents between L and D were 1.47, 3.19 and 2.86 for A. rufinerve, M. australis and V. coignetiae, respectively, whereas those between Apit and D were 0.242, 2.11 and 2.68, respectively. Unlike the inter-specific relationships, the wall resistivity fraction (Rwall/(Rlumen + Rwall)) within xylem changed depending on D. In M. australis and V. coignetiae, this fraction decreased with increasing D, while in A. rufinerve, it increased with D. Vessels with a high wall resistivity fraction have high Rwall and total resistivity but are expected to have low susceptibility to xylem cavitation due to a small cumulative Apit. In contrast, vessels with a low wall resistivity fraction have low Rwall and total resistivity but high susceptibility to xylem cavitation. Because the wall resistivity fraction varies with D, the stem xylem contains vessels with different hydraulic efficiencies and safety to xylem cavitation. These features produce differences in the hydraulic properties

  13. Structural Properties of EB-Welded AlSi10Mg Thin-Walled Pressure Vessels Produced by AM-SLM Technology

    Science.gov (United States)

    Nahmany, Moshe; Stern, Adin; Aghion, Eli; Frage, Nachum

    2017-09-01

    Additive manufacturing of metals by selective laser melting (AM-SLM) is hampered by significant limitations in product size due to the limited dimensions of printing trays. Electron beam welding (EBW) is a well-established process that results in relatively minor metallurgical modifications in workpieces due to the ability of EBW to pass high-density energy to the related substance. The present study aims to evaluate structural properties of EB-welded AlSi10Mg thin-walled pressure vessels produced from components prepared by SLM technology. Following the EB welding process, leak and burst tests were conducted, as was fractography analysis. The welded vessels showed an acceptable holding pressure of 30 MPa, with a reasonable residual deformation up to 2.3% and a leak rate better than 1 × 10-8 std-cc s-1 helium. The failures that occurred under longitudinal stresses reflected the presence of two weak locations in the vessels, i.e., the welded joint region and the transition zone between the vessel base and wall. Fractographic analysis of the fracture surfaces of broken vessels displayed the ductile mode of the rupture, with dimples of various sizes, depending on the failure location.

  14. Structural Properties of EB-Welded AlSi10Mg Thin-Walled Pressure Vessels Produced by AM-SLM Technology

    Science.gov (United States)

    Nahmany, Moshe; Stern, Adin; Aghion, Eli; Frage, Nachum

    2017-10-01

    Additive manufacturing of metals by selective laser melting (AM-SLM) is hampered by significant limitations in product size due to the limited dimensions of printing trays. Electron beam welding (EBW) is a well-established process that results in relatively minor metallurgical modifications in workpieces due to the ability of EBW to pass high-density energy to the related substance. The present study aims to evaluate structural properties of EB-welded AlSi10Mg thin-walled pressure vessels produced from components prepared by SLM technology. Following the EB welding process, leak and burst tests were conducted, as was fractography analysis. The welded vessels showed an acceptable holding pressure of 30 MPa, with a reasonable residual deformation up to 2.3% and a leak rate better than 1 × 10-8 std-cc s-1 helium. The failures that occurred under longitudinal stresses reflected the presence of two weak locations in the vessels, i.e., the welded joint region and the transition zone between the vessel base and wall. Fractographic analysis of the fracture surfaces of broken vessels displayed the ductile mode of the rupture, with dimples of various sizes, depending on the failure location.

  15. Rupture Properties of Blood Vessel Walls Measured by Pressure-Imposed Test

    Science.gov (United States)

    Ohashi, Toshiro; Sugita, Syukei; Matsumoto, Takeo; Kumagai, Kiichiro; Akimoto, Hiroji; Tabayashi, Koichi; Sato, Masaaki

    It is expected to be clinically useful to know the mechanical properties of human aortic aneurysms in assessing the potential for aneurysm rupture. For this purpose, a newly designed experimental setup was fabricated to measure the rupture properties of blood vessel walls. A square specimen of porcine thoracic aortas is inflated by air pressure at a rate of 10mmHg/s (≈1.3MPa/s) until rupture occurs. Mean breaking stress was 1.8±0.4 MPa (mean±SD) for the specimens proximal to the heart and 2.3±0.8MPa for the distal specimens, which are not significantly different to those values obtained longitudinally from conventional tensile tests. Moreover, the local breaking stretch ratio in the longitudinal direction was significantly higher at the ruptured site (2.7±0.5) than at the unruptured site (2.2±0.4). This testing system for studying the rupture properties of aortic walls is expected to be applicable to aortic aneurysms. Experimental verification of the present technique for the homogeneous, isotropic material is also presented.

  16. Added Value of Vessel Wall Magnetic Resonance Imaging for Differentiation of Nonocclusive Intracranial Vasculopathies.

    Science.gov (United States)

    Mossa-Basha, Mahmud; Shibata, Dean K; Hallam, Danial K; de Havenon, Adam; Hippe, Daniel S; Becker, Kyra J; Tirschwell, David L; Hatsukami, Thomas; Balu, Niranjan; Yuan, Chun

    2017-11-01

    Our goal is to determine the added value of intracranial vessel wall magnetic resonance imaging (IVWI) in differentiating nonocclusive vasculopathies compared with luminal imaging alone. We retrospectively reviewed images from patients with both luminal and IVWI to identify cases with clinically defined intracranial vasculopathies: atherosclerosis (intracranial atherosclerotic disease), reversible cerebral vasoconstriction syndrome, and inflammatory vasculopathy. Two neuroradiologists blinded to clinical data reviewed the luminal imaging of defined luminal stenoses/irregularities and evaluated the pattern of involvement to make a presumed diagnosis with diagnostic confidence. Six weeks later, the 2 raters rereviewed the luminal imaging in addition to IVWI for the pattern of wall involvement, presence and pattern of postcontrast enhancement, and presumed diagnosis and confidence. Analysis was performed on per-lesion and per-patient bases. Thirty intracranial atherosclerotic disease, 12 inflammatory vasculopathies, and 12 reversible cerebral vasoconstriction syndrome patients with 201 lesions (90 intracranial atherosclerotic disease, 64 reversible cerebral vasoconstriction syndrome, and 47 inflammatory vasculopathy lesions) were included. For both per-lesion and per-patient analyses, there was significant diagnostic accuracy improvement with luminal imaging+IVWI when compared with luminal imaging alone (per-lesion: 88.8% versus 36.1%; Pimprove the differentiation of nonocclusive intracranial vasculopathies when combined with traditional luminal imaging modalities. © 2017 American Heart Association, Inc.

  17. Optical coherence tomography assessment of vessel wall degradation in thoracic aortic aneurysms

    Science.gov (United States)

    Real, Eusebio; Eguizabal, Alma; Pontón, Alejandro; Díez, Marta Calvo; Fernando Val-Bernal, José; Mayorga, Marta; Revuelta, José M.; López-Higuera, José M.; Conde, Olga M.

    2013-12-01

    Optical coherence tomography images of human thoracic aorta from aneurysms reveal elastin disorders and smooth muscle cell alterations when visualizing the media layer of the aortic wall. These disorders can be employed as indicators for wall degradation and, therefore, become a hallmark for diagnosis of risk of aneurysm under intraoperative conditions. Two approaches are followed to evaluate this risk: the analysis of the reflectivity decay along the penetration depth and the textural analysis of a two-dimensional spatial distribution of the aortic wall backscattering. Both techniques require preprocessing stages for the identification of the air-sample interface and for the segmentation of the media layer. Results show that the alterations in the media layer of the aortic wall are better highlighted when the textural approach is considered and also agree with a semiquantitative histopathological grading that assesses the degree of wall degradation. The correlation of the co-occurrence matrix attains a sensitivity of 0.906 and specificity of 0.864 when aneurysm automatic diagnosis is evaluated with a receiver operating characteristic curve.

  18. Distinct defects in collagen microarchitecture underlie vessel-wall failure in advanced abdominal aneurysms and aneurysms in Marfan syndrome

    NARCIS (Netherlands)

    Lindeman, J.H.N.; Ashcroft, B.A.; Beenakker, J.-W.M.; Es, M. van; Koekkoek, N.B.R.; Prins, F.A.; Tielemans, J.F.; Abdul-Hussien, H.; Bank, R.A.; Oosterkamp, T.H.

    2010-01-01

    An aneurysm of the aorta is a common pathology characterized by segmentalweakeningof the artery.Althoughit isgenerally accepted that the vessel-wall weakening is caused by an impaired collagen metabolism, a clear association has been demonstrated only for rare syndromes such as the vascular type

  19. Effect of Heat Flux on Creep Stresses of Thick-Walled Cylindrical Pressure Vessels

    Directory of Open Access Journals (Sweden)

    Mosayeb Davoudi Kashkoli

    2014-06-01

    Full Text Available Assuming that the thermo-creep response of the material is governed by Norton’s law, an analytical solution is presented for the calculation of time-dependent creep stresses and displacements of homogeneous thick-walled cylindrical pressure vessels. For the stress analysis in a homogeneous pressure vessel, having material creep behavior, the solutions of the stresses at a time equal to zero (i.e. the initial stress state are needed. This corresponds to the solution of materials with linear elastic behavior. Therefore, using equations of equilibrium, stress-strain and strain-displacement, a differential equation for displacement is obtained and then the stresses at a time equal to zero are calculated. Using Norton’s law in the multi-axial form in conjunction with the above-mentioned equations in the rate form, the radial displacement rate is obtained and then the radial, circumferential and axial creep stress rates are calculated. When the stress rates are known, the stresses at any time are calculated iteratively. The analytical solution is obtained for the conditions of plane strain and plane stress. The thermal loading is as follows: inner surface is exposed to a uniform heat flux, and the outer surface is exposed to an airstream. The heat conduction equation for the one-dimensional problem in polar coordinates is used to obtain temperature distribution in the cylinder. The pressure, inner radius and outer radius are considered constant. Material properties are considered as constant. Following this, profiles are plotted for the radial displacements, radial stress, circumferential stress and axial stress as a function of radial direction and time.

  20. Numerical modeling of the pulse wave propagation in large blood vessels based on liquid and wall interaction

    Science.gov (United States)

    Rup, K.; Dróżdż, A.

    2014-08-01

    The purpose of this article is to develop a non-linear, one-dimensional model of pulse wave propagation in the arterial cardiovascular system. The model includes partial differential equations resulting from the balance of mass and momentum for the fluid-filled area and the balance equation for the area of the wall and vessels. The considered mathematical model of pulse wave propagation in the thoracic aorta section takes into account the viscous dissipation of fluid energy, realistic values of parameters describing the physicochemical properties of blood and vessel wall. Boundary and initial conditions contain the appropriate information obtained from in vivo measurements. As a result of the numerical solution of the mass and momentum balance equations for the blood and the equilibrium equation for the arterial wall area, time- dependent deformation, respective velocity profiles and blood pressure were determined.

  1. Manufacturing and maintenance technologies developed for a thick-wall structure of the ITER vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Onozuka, M. E-mail: onozukm@itereu.de; Alfile, J.P.; Aubert, Ph.; Dagenais, J.-F.; Grebennikov, D.; Ioki, K.; Jones, L.; Koizumi, K.; Krylov, V.; Maslakowski, J.; Nakahira, M.; Nelson, B.; Punshon, C.; Roy, O.; Schreck, G

    2001-09-01

    Development of welding, cutting and non-destructive testing (NDT) techniques, and development of remotized systems have been carried out for on-site manufacturing and maintenance of the thick-wall structure of the International Thermonuclear Experimental Reactor (ITER) vacuum vessel (VV). Conventional techniques, including tungsten inert gas welding, plasma cutting, and ultrasonic inspection, have been improved and optimized for the application to thick austenitic stainless steel plates. In addition, advanced methods have been investigated, including reduced-pressure electron-beam and multi-pass neodymium-doped yttrium aluminum garnet (NdYAG) laser welding, NdYAG laser cutting, and electro-magnetic acoustic transducer inspection, to improve cost and technical performance. Two types of remotized systems with different payloads have been investigated and one of them has been fabricated and demonstrated in field joint welding, cutting, and NDT tests on test mockups and full-scale ITER VV sector models. The progress and results of this development to date provide a high level of confidence that the manufacturing and maintenance of the ITER VV is feasible.

  2. Preliminary electromagnetic, thermal and mechanical design for first wall and vacuum vessel of FAST

    Energy Technology Data Exchange (ETDEWEB)

    Lucca, F., E-mail: Flavio.Lucca@LTCalcoli.it [LT Calcoli srl, Piazza Prinetti 26/B, 23807 Merate, LC (Italy); Bertolini, C. [LT Calcoli srl, Piazza Prinetti 26/B, 23807 Merate, LC (Italy); Crescenzi, F.; Crisanti, F. [C.R. ENEA Frascati – UT FUS, Via E. Fermi 45, IT-00044 Frascati, RM (Italy); Di Gironimo, G. [CREATE, Università di Napoli Federico II, P.le Tecchio 80, 80125 Napoli (Italy); Labate, C. [CREATE, Università di Napoli Parthenope, Via Acton 38, 80133 Napoli (Italy); Manzoni, M.; Marconi, M.; Pagani, I. [LT Calcoli srl, Piazza Prinetti 26/B, 23807 Merate, LC (Italy); Ramogida, G. [C.R. ENEA Frascati – UT FUS, Via E. Fermi 45, IT-00044 Frascati, RM (Italy); Renno, F. [CREATE, Università di Napoli Federico II, P.le Tecchio 80, 80125 Napoli (Italy); Roccella, M. [LT Calcoli srl, Piazza Prinetti 26/B, 23807 Merate, LC (Italy); Roccella, S. [C.R. ENEA Frascati – UT FUS, Via E. Fermi 45, IT-00044 Frascati, RM (Italy); Viganò, F. [LT Calcoli srl, Piazza Prinetti 26/B, 23807 Merate, LC (Italy)

    2015-10-15

    The fusion advanced study torus (FAST), with its compact design, high toroidal field and plasma current, faces many of the problems met by ITER, and at the same time anticipates much of the DEMO relevant physics and technology. The conceptual design of the first wall (FW) and the vacuum vessel (VV) has been defined on the basis of FAST operative conditions and of “Snow Flakes” (SF) magnetic topology, which is also relevant for DEMO. The EM loads are one of the most critical load components for the FW and the VV during plasma disruptions and a first dimensioning of these components for such loads is mandatory. During this first phase of R&D activities the conceptual design of the FW and VV have been assessed estimating, by means of FE simulations, the EM loads due to a typical vertical disruption event (VDE) in FAST. EM loads were then transferred on a FE mechanical model of the FAST structures and the mechanical response of the FW and VV design for the analyzed VDE event was assessed. The results indicate that design criteria are not fully satisfied by the current drawing of the VV and FW components. The most critical regions have been individuated and the effect of some geometrical and material changes has been checked in order to improve the structure.

  3. "Choke" vessels between vascular territories of the abdominal wall: literature review and rare case of Leriche's syndrome.

    Science.gov (United States)

    Ye, Xuan; Rozen, Warren M; Alonso-Burgos, Alberto; Ashton, Mark W

    2012-11-01

    We undertook a review of the anatomical changes of "choke" vessels between the internal thoracic artery (ITA) and deep inferior epigastric artery (DIEA), as highlighted by a case of aortoiliac occlusive disease (Leriche's syndrome), and discuss the physiological concepts observed with regard to surgical delay procedures within the abdominal wall performed prior to abdominal cutaneous free flaps and coronary artery bypass grafting. Computed tomographic angiography (CTA) was undertaken on a patient with a rare case of Leriche's syndrome and a literature review of over 200 references on the anatomy, physiology and clinical uses of choke vessels in the abdominal wall was undertaken. The CTA demonstrated that in patients with Leriche's syndrome, there is a marked dilatation of all ITA-DIEA pathways and increased flow through choke vessels. If these changes can be surgically replicated in the form of a delay procedure for patients seeking to undergo autologous breast construction, this could improve the outcomes of abdominal cutaneous free flaps and coronary artery bypass grafting. We accordingly propose three surgical methods for augmenting blood flow to the abdominal wall: a) ligation of the DIEA; b) ligation of the distal ITA; and c) creation of an arterio-venous fistulae in the DIEA. Our review of the literature confirmed the viability of these propositions. The dilatation of choke vessels in response to increased haemodynamic stress may thus be utilised to enhance blood supply to tissues prior to transfer and can be achieved through simple and minimally invasive methods. Copyright © 2012 Wiley Periodicals, Inc.

  4. Atypical variants of nodular lymphocyte-predominant Hodgkin lymphoma show low microvessel density and vessels of distention type.

    Science.gov (United States)

    Scheidt, Victoria; Hansmann, Martin-Leo; Schuhmacher, Bianca; Döring, Claudia; Hartmann, Sylvia

    2017-02-01

    Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) presents different histopathologic growth patterns, including atypical forms showing overlapping histopathologic and clinical features with T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL). Because growth patterns are associated with vessel distribution, the aim of the present study was to compare angiogenesis in different NLPHL patterns with THRLBCL as well as other lymphomas. Atypical variants of NLPHL and THRLBCL (n=10 per group) both showed a low microvessel density (MVD; 1.16-1.31/μm2) with a diffuse vessel distribution. In contrast, in typical NLPHL (n=10), follicular areas with low MVD were retained, whereas an increase in vessels in the interfollicular areas was observed (MVD 1.35/μm2). THRLBCL and typical NLPHL could additionally be distinguished by differences in their molecular angiogenesis signature. Furthermore, the number of intravascular T cells was significantly reduced in THRLBCL (0.0028 T cells/mm2 vessel area) when compared with typical NLPHL (0.0059 T cells/mm2 vessel area), potentially reflecting the different composition of the microenvironment in these 2 lymphoma entities. The results of our study reveal a similar vascular pattern and angiogenesis behavior in atypical NLPHL variants and THRLBCL in contrast to the retained follicular pattern in typical NLPHL. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Cell culture for three-dimensional modeling in rotating-wall vessels: an application of simulated microgravity

    Science.gov (United States)

    Schwarz, R. P.; Goodwin, T. J.; Wolf, D. A.

    1992-01-01

    High-density, three-dimensional cell cultures are difficult to grow in vitro. The rotating-wall vessel (RWV) described here has cultured BHK-21 cells to a density of 1.1 X 10(7) cells/ml. Cells on microcarriers were observed to grow with enhanced bridging in this batch culture system. The RWV is a horizontally rotated tissue culture vessel with silicon membrane oxygenation. This design results in a low-turbulence, low-shear cell culture environment with abundant oxygenation. The RWV has the potential to culture a wide variety of normal and neoplastic cells.

  6. Characterization of atherosclerotic disease in thoracic aorta: A 3D, multicontrast vessel wall imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Changwu [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China); Department of Radiology, The Second Clinical Medical College, Yangzhou University, Yangzhou (China); Qiao, Huiyu; He, Le [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China); Yuan, Chun [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China); Department of Radiology, University of Washington, Seattle, WA (United States); Chen, Huijun; Zhang, Qiang; Li, Rui [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China); Wang, Wei; Du, Fang [Department of Radiology, The Second Clinical Medical College, Yangzhou University, Yangzhou (China); Li, Cheng, E-mail: cjr.licheng@vip.163.com [Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing (China); Zhao, Xihai, E-mail: xihaizhao@tsinghua.edu.cn [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China)

    2016-11-15

    Purpose: To investigate the characteristics of plaque in the thoracic aorta using three dimensional multicontrast magnetic resonance imaging. Materials and methods: Elderly subjects (≥60 years) were recruited in this study. Thoracic aorta was imaged on a 3.0T MR scanner by acquiring multicontrast sequences. The plaque burden was evaluated by measuring lumen area, wall area, wall thickness, and normalized wall index. The presence or absence of plaque and intraplaque hemorrhage (IPH)/mural thrombus (MT) were identified. The characteristics of atherosclerosis among different thoracic aorta segments (AAO: ascending aorta; AOA: aortic arch, and DOA: descending aorta) were determined. Results: Of 66 recruited subjects (mean age 72.3 ± 6.2 years, 30 males), 55 (83.3%) had plaques in the thoracic aorta. The prevalence of plaque in AAO, AOA, and DAO was 5.4%, 72.7%, and 71.2%, respectively. In addition, 21.2% of subjects were found to have lesions with IPH/MT in the thoracic aorta. The prevalence of IPH/MT in segment of AAO, AOA and DAO was 0%, 13.6%, and 12.1%, respectively. The aortic wall showed the highest NWI in DAO (34.1% ± 4.8%), followed by AOA (31.2% ± 5%), and AAO (26.8% ± 3.3%) (p < 0.001). Conclusion: Three dimensional multicontrast MR imaging is capable of characterizing atherosclerotic plaques in the thoracic aorta. The findings of high prevalence of plaques and the presence of high risk plaques in the thoracic aorta suggest early screening for aortic vulnerable lesions in the elderly.

  7. Suitability of pharmacokinetic models for dynamic contrast-enhanced MRI of abdominal aortic aneurysm vessel wall: a comparison.

    Directory of Open Access Journals (Sweden)

    V Lai Nguyen

    Full Text Available PURPOSE: Increased microvascularization of the abdominal aortic aneurysm (AAA vessel wall has been related to AAA progression and rupture. The aim of this study was to compare the suitability of three pharmacokinetic models to describe AAA vessel wall enhancement using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI. MATERIALS AND METHODS: Patients with AAA underwent DCE-MRI at 1.5 Tesla. The volume transfer constant (K(trans , which reflects microvascular flow, permeability and surface area, was calculated by fitting the blood and aneurysm vessel wall gadolinium concentration curves. The relative fit errors, parameter uncertainties and parameter reproducibilities for the Patlak, Tofts and Extended Tofts model were compared to find the most suitable model. Scan-rescan reproducibility was assessed using the interclass correlation coefficient and coefficient of variation (CV. Further, the relationship between K(trans and AAA size was investigated. RESULTS: DCE-MRI examinations from thirty-nine patients (mean age±SD: 72±6 years; M/F: 35/4 with an mean AAA maximal diameter of 49±6 mm could be included for pharmacokinetic analysis. Relative fit uncertainties for K(trans based on the Patlak model (17% were significantly lower compared to the Tofts (37% and Extended Tofts model (42% (p<0.001. K(trans scan-rescan reproducibility for the Patlak model (ICC = 0.61 and CV = 22% was comparable with the Tofts (ICC = 0.61, CV = 23% and Extended Tofts model (ICC = 0.76, CV = 22%. K(trans was positively correlated with maximal AAA diameter (Spearman's ρ = 0.38, p = 0.02 using the Patlak model. CONCLUSION: Using the presented imaging protocol, the Patlak model is most suited to describe DCE-MRI data of the AAA vessel wall with good K(trans scan-rescan reproducibility.

  8. Computerized flow and vessel wall analyses of coronary arteries for detection of non-calcified plaques in coronary CT angiography

    Science.gov (United States)

    Wei, Jun; Zhou, Chuan; Chan, Heang-Ping; Chughtai, Aamer; Agarwal, Prachi; Hadjiiski, Lubomir; Kazerooni, Ella

    2016-03-01

    The buildup of non-calcified plaques (NCP) that are vulnerable to rupture in coronary arteries is a risk for myocardial infarction. We are developing a computer-aided detection (CADe) system to assist radiologists in detecting NCPs in cCTA. A major challenge of NCP detection is the large number of false positives (FPs) caused by the small sized coronary arteries, image noise and artifacts. In this study, our purpose is to design new image features to reduce FPs. A data set of 98 cCTA scans was retrospectively collected from patient files. We first used vessel wall analysis, in which topological features were extracted from vessel wall and fused with a support-vector machine, to identify the NCP candidates from the segmented coronary tree. Computerized flow dynamic (CFD) features that characterize the change in blood flow due to the presence of plaques and a vascular cross-sectional (VCS) feature that quantifies the presence of low attenuation region at the vessel wall were designed for FP reduction. Using a leave-one-out resampling method, a support vector machine classifier was trained to merge the features into a NCP likelihood score using the vessel wall features alone or in combination with the new CDF and VCS features. The performance of the new features in classification of true NCPs and FPs was evaluated by the area under the receiver operating characteristic (ROC) curve (AUC). Without the new CFD and VCS features, the test AUC was 0.84+/-0.01. The AUC was improved to 0.88+/-0.01 with the addition of the new features. The improvement was statistically significant (p < 0.001). The study indicated that the new flow dynamic and vascular cross-sectional features were useful for differentiation of NCPs from FPs in cCTA.

  9. Dilated thin-walled blood and lymphatic vessels in human endometrium: a potential role for VEGF-D in progestin-induced break-through bleeding.

    Directory of Open Access Journals (Sweden)

    Jacqueline F Donoghue

    Full Text Available Progestins provide safe, effective and cheap options for contraception as well as the treatment of a variety of gynaecological disorders. Episodes of irregular endometrial bleeding or breakthrough bleeding (BTB are a major unwanted side effect of progestin treatment, such that BTB is the leading cause for discontinued use of an otherwise effective and popular medication. The cellular mechanisms leading to BTB are poorly understood. In this study, we make the novel finding that the large, dilated, thin walled vessels characteristic of human progestin-treated endometrium include both blood and lymphatic vessels. Increased blood and lymphatic vessel diameter are features of VEGF-D action in other tissues and we show by immunolocalisation and Western blotting that stromal cell decidualisation results in a significant increase in VEGF-D protein production, particularly of the proteolytically processed 21 kD form. Using a NOD/scid mouse model with xenografted human endometrium we were able to show that progestin treatment causes decidualisation, VEGF-D production and endometrial vessel dilation. Our results lead to a novel hypothesis to explain BTB, with stromal cell decidualisation rather than progestin treatment per se being the proposed causative event, and VEGF-D being the proposed effector agent.

  10. Vessel Wall Enhancement and Blood-Cerebrospinal Fluid Barrier Disruption After Mechanical Thrombectomy in Acute Ischemic Stroke.

    Science.gov (United States)

    Renú, Arturo; Laredo, Carlos; Lopez-Rueda, Antonio; Llull, Laura; Tudela, Raúl; San-Roman, Luis; Urra, Xabier; Blasco, Jordi; Macho, Juan; Oleaga, Laura; Chamorro, Angel; Amaro, Sergio

    2017-03-01

    Less than half of acute ischemic stroke patients treated with mechanical thrombectomy obtain permanent clinical benefits. Consequently, there is an urgent need to identify mechanisms implicated in the limited efficacy of early reperfusion. We evaluated the predictors and prognostic significance of vessel wall permeability impairment and its association with blood-cerebrospinal fluid barrier (BCSFB) disruption after acute stroke treated with thrombectomy. A prospective cohort of acute stroke patients treated with stent retrievers was analyzed. Vessel wall permeability impairment was identified as gadolinium vessel wall enhancement (GVE) in a 24- to 48-hour follow-up contrast-enhanced magnetic resonance imaging, and severe BCSFB disruption was defined as subarachnoid hemorrhage or gadolinium sulcal enhancement (present across >10 slices). Infarct volume was evaluated in follow-up magnetic resonance imaging, and clinical outcome was evaluated with the modified Rankin Scale at day 90. A total of 60 patients (median National Institutes of Health Stroke Scale score, 18) were analyzed, of whom 28 (47%) received intravenous alteplase before mechanical thrombectomy. Overall, 34 (57%) patients had GVE and 27 (45%) had severe BCSFB disruption. GVE was significantly associated with alteplase use before thrombectomy and with more stent retriever passes, along with the presence of severe BCSFB disruption. GVE was associated with poor clinical outcome, and both GVE and severe BCSFB disruption were associated with increased final infarct volume. These findings may support the clinical relevance of direct vessel damage and BCSFB disruption after acute stroke and reinforce the need for further improvements in reperfusion strategies. Further validation in larger cohorts of patients is warranted. © 2017 American Heart Association, Inc.

  11. Airway wall thickening and emphysema show independent familial aggregation in chronic obstructive pulmonary disease

    DEFF Research Database (Denmark)

    Patel, Bipen D; Coxson, Harvey O; Pillai, Sreekumar G

    2008-01-01

    RATIONALE: It is unclear whether airway wall thickening and emphysema make independent contributions to airflow limitation in chronic obstructive pulmonary disease (COPD) and whether these phenotypes cluster within families. OBJECTIVES: To determine whether airway wall thickening and emphysema (1...... the severity of airway wall thickening and emphysema. MEASUREMENTS AND MAIN RESULTS: A total of 3,096 individuals were recruited to the study, of whom 1,159 (519 probands and 640 siblings) had technically adequate high-resolution computed tomography scans without significant non-COPD-related thoracic disease....... Airway wall thickness correlated with pack-years smoked (P chronic bronchitis (P emphysema at -950...

  12. Transient Non-Newtonian Blood Flow under Magnetic Targeting Drug Delivery in an Aneurysm Blood Vessel with Porous Walls

    Science.gov (United States)

    Alimohamadi, Haleh; Imani, Mohsen

    2014-11-01

    The present investigation deals with numerical solution of blood flow patterns through an aneurysm artery under the applied magnetic field. Transient extended Navier-Stokes, Brinkman, continuity, and heat conduction equations govern this phenomenon and unsteady pulsatile inlet velocity varies by human heart-beating frequency. Our simulation demonstrates applying 105 magnetic field intensity (MnF) to recirculate flow and increase fluid flux and maximum blood temperature by 62.5x and 3.5%, respectively, in the aneurysm region. It is also shown that the vessel's wall porosity plays an important role in magnetic targeting of drug delivery performance, as this parameter can noticeably change maximum blood temperature and pressure.

  13. Detection of vessel wall calcifications in vertebral arteries using susceptibility weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Lisa C.; Boeker, Sarah M.; Bender, Yvonne Y.; Fallenberg, Eva M.; Wagner, Moritz; Hamm, Bernd; Makowski, Marcus R. [Department of Radiology, Charite, Berlin (Germany); Liebig, Thomas [Department of Neuroradiology, Charite, Berlin (Germany)

    2017-09-15

    Calcification of the brain supplying arteries has been linked to an increased risk for cerebrovascular disease. The purpose of this study was to test the potential of susceptibility weighted MR imaging (SWMR) for the detection of vertebral artery calcifications, based on CT as a reference standard. Four hundred seventy-four patients, who had received head CT and 1.5 T MR scans with SWMR, including the distal vertebral artery, between January 2014 and December 2016, were retrospectively evaluated and 389 patients were included. Sensitivity and specificity for the detection of focal calcifications and intra- and interobserver agreement were calculated for SWMR and standard MRI, using CT as a standard of reference. The diameter of vertebral artery calcifications was used to assess correlations between imaging modalities. Furthermore, the degree of vessel stenosis was determined in 30 patients, who had received an additional angiography. On CT scans, 40 patients showed a total of 52 vertebral artery calcifications. While SWMR reached a sensitivity of 94% (95% CI 84-99%) and a specificity of 97% (95% CI 94-98%), standard MRI yielded a sensitivity of 33% (95% CI 20-46%), and a specificity of 93% (95% CI 90-96%). Linear regression analysis of size measurements confirmed a close correlation between SWMR and CT measurements (R {sup 2} = 0.74, p < 0.001). Compared to standard MRI (ICC = 0.52; CI 0.45-0.59), SWMR showed a higher interobserver agreement for calcification measurements (ICC = 0.84; CI 0.81-0.87). For detection of distal vertebral artery calcifications, SWMR demonstrates a performance comparable to CT and considerably higher than conventional MRI. (orig.)

  14. Differentiation of deep subcortical infarction using high-resolution vessel wall MR imaging of middle cerebral artery

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Yun Jung; Choi, Byung Se; Jung, Cheol Kyu; Yoon, Yeon Hong; Sunwoo, Leonard; Kim, Jae Hyoung; Bae, Hee Joon [Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of)

    2017-11-15

    To evaluate the utility of high-resolution vessel wall imaging (HR-VWI) of middle cerebral artery (MCA), and to compare HR-VWI findings between striatocapsular infarction (SC-I) and lenticulostriate infarction (LS-I). This retrospective study was approved by the Institutional Review Board, and informed consent was waived. From July 2009 to February 2012, 145 consecutive patients with deep subcortical infarctions (SC-I, n = 81; LS-I, n = 64) who underwent HR-VWI were included in this study. The degree of MCA stenosis and the characteristics of MCA plaque (presence, eccentricity, location, extent, T2-high signal intensity [T2-HSI], and plaque enhancement) were analyzed, and compared between SC-I and LS-I, using Fisher's exact test. Stenosis was more severe in SC-I than in LS-I (p = 0.040). MCA plaque was more frequent in SC-I than in LS-I (p = 0.028), having larger plaque extent (p = 0.001), more T2-HSI (p = 0.001), and more plaque enhancement (p = 0.002). The eccentricity and location of the plaque showed no significant difference between the two groups.Both SC-I and LS-I have similar HR-VWI findings of the MCA plaque, but SC-I had more frequent, larger plaques with greater T2-HSI and enhancement. This suggests that HR-VWI may have a promising role in assisting the differentiation of underlying pathophysiological mechanism between SC-I and LS-I.

  15. Construction and characterisation of MRI coils for vessel wall imaging at 7 tesla

    OpenAIRE

    2014-01-01

    Atherosclerotic plaques in the bifurcation of the carotid artery vessels can pose a significant stroke risk from stenosis, thrombosis and emboli, or plaque rupture. However, the possibility of the latter depends on the structure of the plaque and its stability. So far, the assessment of such depositions, and the evaluation of the risk they pose, is not satisfactory with 3 Tesla black blood imaging. It is expected that the SNR increase at 7 Tesla, together with an appropriate and patient-safe ...

  16. Vascular wall-resident CD44+ multipotent stem cells give rise to pericytes and smooth muscle cells and contribute to new vessel maturation.

    Directory of Open Access Journals (Sweden)

    Diana Klein

    Full Text Available Here, we identify CD44(+CD90(+CD73(+CD34(-CD45(- cells within the adult human arterial adventitia with properties of multipotency which were named vascular wall-resident multipotent stem cells (VW-MPSCs. VW-MPSCs exhibit typical mesenchymal stem cell characteristics including cell surface markers in immunostaining and flow cytometric analyses, and differentiation into adipocytes, chondrocytes and osteocytes under culture conditions. Particularly, TGFß1 stimulation up-regulates smooth muscle cell markers in VW-MPSCs. Using fluorescent cell labelling and co-localisation studies we show that VW-MPSCs differentiate to pericytes/smooth muscle cells which cover the wall of newly formed endothelial capillary-like structures in vitro. Co-implantation of EGFP-labelled VW-MPSCs and human umbilical vein endothelial cells into SCID mice subcutaneously via Matrigel results in new vessels formation which were covered by pericyte- or smooth muscle-like cells generated from implanted VW-MPSCs. Our results suggest that VW-MPSCs are of relevance for vascular morphogenesis, repair and self-renewal of vascular wall cells and for local capacity of neovascularization in disease processes.

  17. Accelerated whole brain intracranial vessel wall imaging using black blood fast spin echo with compressed sensing (CS-SPACE).

    Science.gov (United States)

    Zhu, Chengcheng; Tian, Bing; Chen, Luguang; Eisenmenger, Laura; Raithel, Esther; Forman, Christoph; Ahn, Sinyeob; Laub, Gerhard; Liu, Qi; Lu, Jianping; Liu, Jing; Hess, Christopher; Saloner, David

    2017-12-05

    Develop and optimize an accelerated, high-resolution (0.5 mm isotropic) 3D black blood MRI technique to reduce scan time for whole-brain intracranial vessel wall imaging. A 3D accelerated T 1 -weighted fast-spin-echo prototype sequence using compressed sensing (CS-SPACE) was developed at 3T. Both the acquisition [echo train length (ETL), under-sampling factor] and reconstruction parameters (regularization parameter, number of iterations) were first optimized in 5 healthy volunteers. Ten patients with a variety of intracranial vascular disease presentations (aneurysm, atherosclerosis, dissection, vasculitis) were imaged with SPACE and optimized CS-SPACE, pre and post Gd contrast. Lumen/wall area, wall-to-lumen contrast ratio (CR), enhancement ratio (ER), sharpness, and qualitative scores (1-4) by two radiologists were recorded. The optimized CS-SPACE protocol has ETL 60, 20% k-space under-sampling, 0.002 regularization factor with 20 iterations. In patient studies, CS-SPACE and conventional SPACE had comparable image scores both pre- (3.35 ± 0.85 vs. 3.54 ± 0.65, p = 0.13) and post-contrast (3.72 ± 0.58 vs. 3.53 ± 0.57, p = 0.15), but the CS-SPACE acquisition was 37% faster (6:48 vs. 10:50). CS-SPACE agreed with SPACE for lumen/wall area, ER measurements and sharpness, but marginally reduced the CR. In the evaluation of intracranial vascular disease, CS-SPACE provides a substantial reduction in scan time compared to conventional T 1 -weighted SPACE while maintaining good image quality.

  18. Statistical Permutation-based Artery Mapping (SPAM): a novel approach to evaluate imaging signals in the vessel wall.

    Science.gov (United States)

    Seifert, Robert; Scherzinger, Aaron; Kiefer, Friedemann; Hermann, Sven; Jiang, Xiaoyi; Schäfers, Michael A

    2017-05-26

    Cardiovascular diseases are the leading cause of death worldwide. A prominent cause of cardiovascular events is atherosclerosis, a chronic inflammation of the arterial wall that leads to the formation of so called atherosclerotic plaques. There is a strong clinical need to develop new, non-invasive vascular imaging techniques in order to identify high-risk plaques, which might escape detection using conventional methods based on the assessment of the luminal narrowing. In this context, molecular imaging strategies based on fluorescent tracers and fluorescence reflectance imaging (FRI) seem well suited to assess molecular and cellular activity. However, such an analysis demands a precise and standardized analysis method, which is orientated on reproducible anatomical landmarks, ensuring to compare equivalent regions across different subjects. We propose a novel method, Statistical Permutation-based Artery Mapping (SPAM). Our approach is especially useful for the understanding of complex and heterogeneous regional processes during the course of atherosclerosis. Our method involves three steps, which are (I) standardisation with an additional intensity normalization, (II) permutation testing, and (III) cluster-enhancement. Although permutation testing and cluster enhancement are already well-established in functional magnetic resonance imaging, to the best of our knowledge these strategies have so far not been applied in cardiovascular molecular imaging. We tested our method using FRI images of murine aortic vessels in order to find recurring patterns in atherosclerotic plaques across multiple subjects. We demonstrate that our pixel-wise and cluster-enhanced testing approach is feasible and useful to analyse tracer distributions in FRI data sets of aortic vessels. We expect our method to be a useful tool within the field of molecular imaging of atherosclerotic plaques since cluster-enhanced permutation testing is a powerful approach for finding significant differences

  19. Formation of three-dimensional cell/polymer constructs for bone tissue engineering in a spinner flask and a rotating wall vessel bioreactor

    Science.gov (United States)

    Sikavitsas, Vassilios I.; Bancroft, Gregory N.; Mikos, Antonios G.; McIntire, L. V. (Principal Investigator)

    2002-01-01

    The aim of this study is to investigate the effect of the cell culture conditions of three-dimensional polymer scaffolds seeded with rat marrow stromal cells (MSCs) cultured in different bioreactors concerning the ability of these cells to proliferate, differentiate towards the osteoblastic lineage, and generate mineralized extracellular matrix. MSCs harvested from male Sprague-Dawley rats were culture expanded, seeded on three-dimensional porous 75:25 poly(D,L-lactic-co-glycolic acid) biodegradable scaffolds, and cultured for 21 days under static conditions or in two model bioreactors (a spinner flask and a rotating wall vessel) that enhance mixing of the media and provide better nutrient transport to the seeded cells. The spinner flask culture demonstrated a 60% enhanced proliferation at the end of the first week when compared to static culture. On day 14, all cell/polymer constructs exhibited their maximum alkaline phosphatase activity (AP). Cell/polymer constructs cultured in the spinner flask had 2.4 times higher AP activity than constructs cultured under static conditions on day 14. The total osteocalcin (OC) secretion in the spinner flask culture was 3.5 times higher than the static culture, with a peak OC secretion occurring on day 18. No considerable AP activity and OC secretion were detected in the rotating wall vessel culture throughout the 21-day culture period. The spinner flask culture had the highest calcium content at day 14. On day 21, the calcium deposition in the spinner flask culture was 6.6 times higher than the static cultured constructs and over 30 times higher than the rotating wall vessel culture. Histological sections showed concentration of cells and mineralization at the exterior of the foams at day 21. This phenomenon may arise from the potential existence of nutrient concentration gradients at the interior of the scaffolds. The better mixing provided in the spinner flask, external to the outer surface of the scaffolds, may explain the

  20. Rôle of contrast media viscosity in altering vessel wall shear stress and relation to the risk of contrast extravasations.

    Science.gov (United States)

    Sakellariou, Sophia; Li, Wenguang; Paul, Manosh C; Roditi, Giles

    2016-12-01

    Iodinated contrast media (CM) are the most commonly used injectables in radiology today. A range of different media are commercially available, combining various physical and chemical characteristics (ionic state, osmolality, viscosity) and thus exhibiting distinct in vivo behaviour and safety profiles. In this paper, numerical simulations of blood flow with contrast media were conducted to investigate the effects of contrast viscosity on generated vessel wall shear stress and vessel wall pressure to elucidate any possible relation to extravasations. Five different types of contrast for Iodine fluxes ranging at 1.5-2.2gI/s were modelled through 18G and 20G cannulae placed in an ideal vein at two different orientation angles. Results demonstrate that the least viscous contrast media generate the least maximum wall shear stress as well as the lowest total pressure for the same flow rate. This supports the empirical clinical observations and hypothesis that more viscous contrast media are responsible for a higher percentage of contrast extravasations. In addition, results support the clinical hypothesis that a catheter tip directed obliquely to the vein wall always produces the highest maximum wall shear stress and total pressure due to impingement of the contrast jet on the vessel wall. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  1. Protein-Bound Uremic Toxins Stimulate Crosstalk between Leukocytes and Vessel Wall

    Science.gov (United States)

    Glorieux, Griet; Schepers, Eva; Cohen, Gerald; Gondouin, Bertrand; Van Landschoot, Maria; Eloot, Sunny; Rops, Angelique; Van de Voorde, Johan; De Vriese, An; van der Vlag, Johan; Brunet, Philippe; Van Biesen, Wim; Vanholder, Raymond

    2013-01-01

    Leukocyte activation and endothelial damage both contribute to cardiovascular disease, a major cause of morbidity and mortality in CKD. Experimental in vitro data link several protein-bound uremic retention solutes to the modulation of inflammatory stimuli, including endothelium and leukocyte responses and cardiovascular damage, corroborating observational in vivo data. However, the impact of these uremic toxins on the crosstalk between endothelium and leukocytes has not been assessed. This study evaluated the effects of acute and continuous exposure to uremic levels of indoxylsulfate (IS), p-cresylsulfate (pCS), and p-cresylglucuronide (pCG) on the recruitment of circulating leukocytes in the rat peritoneal vascular bed using intravital microscopy. Superfusion with IS induced strong leukocyte adhesion, enhanced extravasation, and interrupted blood flow, whereas pCS caused a rapid increase in leukocyte rolling. Superfusion with pCS and pCG combined caused impaired blood flow and vascular leakage but did not further enhance leukocyte rolling over pCS alone. Intravenous infusion with IS confirmed the superfusion results and caused shedding of heparan sulfate, pointing to disruption of the glycocalyx as the mechanism likely mediating IS-induced flow stagnation. These results provide the first clear in vivo evidence that IS, pCS, and pCG exert proinflammatory effects that contribute to vascular damage by stimulating crosstalk between leukocytes and vessels. PMID:24009240

  2. {sup 18}F-fluoroethylcholine uptake in arterial vessel walls and cardiovascular risk factors. Correlation in a PET-CT study

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, Stefan; Rominger, A.; Cumming, P.; Bartenstein, P.; Hacker, M. [Technische Univ. Muenchen (TUM) (Germany). Dept. of Nuclear Medicine; Saam, T.; Nikolaou, K.; Reiser, M.F. [Univ. Muenchen (Germany). Inst. of Clinical Radiology; Wolpers, S. [Technische Univ. Muenchen (TUM) (Germany). Dept. of Nuclear Medicine; Univ. Muenchen (Germany). Inst. of Clinical Radiology

    2010-07-01

    Fluorine-labelled choline derivatives were recently suggested as agents for visualizing vulnerable atherosclerotic plaques. We therefore aimed to evaluate the association between {sup 18}F-fluorethylcholine (FEC) uptake in the wall of large arteries, where calcification was also measured, with the presence of cardiovascular risk factors and occurrence of prior cardiovascular events. Detailed clinical information, including common cardiovascular risk factors, was obtained retrospectively in 60 prostate cancer patients examined with whole-body FEC PET-CT. In each patient, we calculated the mean blood pool-corrected SUV, as well as the mean target-to-background ratio (TBR), in addition to the sum of calcified plaques (CP{sub sum}) from six major vessels: ascending and descending aorta, aortic arch, abdominal aorta, and both iliac arteries. As reported previously, the CP{sub sum} correlated significantly with cardiovascular risk factors, in contrast to mean SUV or TBR scores, which did not show any significance with the presence of cardiovascular risk factors. There was no correlation between CP{sub sum}, mean TBR or SUV, nor was there any significant association of CP{sub sum}, mean TBR or SUV with the prior occurrence of cardio- or cerebrovascular events. Contrary to a recent report, we found in our rather large cohort of elderly prostate cancer patients no significant association between FEC uptake in large vessels and atherosclerotic plaque burden, or the presence of cardiovascular risk factors. In line with prior reports on structural changes in vessels, increased calcified atherosclerotic plaque burden was strongly associated with the occurrence of common cardiovascular risk factors. (orig.)

  3. Three-Dimensional Rotating Wall Vessel-Derived Cell Culture Models for Studying Virus-Host Interactions

    Directory of Open Access Journals (Sweden)

    Jameson K. Gardner

    2016-11-01

    Full Text Available The key to better understanding complex virus-host interactions is the utilization of robust three-dimensional (3D human cell cultures that effectively recapitulate native tissue architecture and model the microenvironment. A lack of physiologically-relevant animal models for many viruses has limited the elucidation of factors that influence viral pathogenesis and of complex host immune mechanisms. Conventional monolayer cell cultures may support viral infection, but are unable to form the tissue structures and complex microenvironments that mimic host physiology and, therefore, limiting their translational utility. The rotating wall vessel (RWV bioreactor was designed by the National Aeronautics and Space Administration (NASA to model microgravity and was later found to more accurately reproduce features of human tissue in vivo. Cells grown in RWV bioreactors develop in a low fluid-shear environment, which enables cells to form complex 3D tissue-like aggregates. A wide variety of human tissues (from neuronal to vaginal tissue have been grown in RWV bioreactors and have been shown to support productive viral infection and physiological meaningful host responses. The in vivo-like characteristics and cellular features of the human 3D RWV-derived aggregates make them ideal model systems to effectively recapitulate pathophysiology and host responses necessary to conduct rigorous basic science, preclinical and translational studies.

  4. Accelerated and Improved Differentiation of Retinal Organoids from Pluripotent Stem Cells in Rotating-Wall Vessel Bioreactors

    Directory of Open Access Journals (Sweden)

    Tyler DiStefano

    2018-01-01

    Full Text Available Pluripotent stem cells can be differentiated into 3D retinal organoids, with major cell types self-patterning into a polarized, laminated architecture. In static cultures, organoid development may be hindered by limitations in diffusion of oxygen and nutrients. Herein, we report a bioprocess using rotating-wall vessel (RWV bioreactors to culture retinal organoids derived from mouse pluripotent stem cells. Organoids in RWV demonstrate enhanced proliferation, with well-defined morphology and improved differentiation of neurons including ganglion cells and S-cone photoreceptors. Furthermore, RWV organoids at day 25 (D25 reveal similar maturation and transcriptome profile as those at D32 in static culture, closely recapitulating spatiotemporal development of postnatal day 6 mouse retina in vivo. Interestingly, however, retinal organoids do not differentiate further under any in vitro condition tested here, suggesting additional requirements for functional maturation. Our studies demonstrate that bioreactors can accelerate and improve organoid growth and differentiation for modeling retinal disease and evaluation of therapies.

  5. Neutron fluence at the reactor pressure vessel wall - a comparison of French and German procedures and strategies in PWRs

    Energy Technology Data Exchange (ETDEWEB)

    Tricot, N. [Institut de Radioprotection et de Surete Nucleaire, IRSN/DES/SECCA, 92 - Fontenay aux Roses (France); Jendrich, U. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Garching (Germany)

    2003-01-01

    While the neutrons within the core may take part in the chain reaction, those neutrons emitted from the core are basically lost for the energy production. This 'neutron leakage' represents a loss of fuel efficiency and causes neutron embrittlement of the reactor pressure vessel (RPV) wall. The latter raises safety concerns, needs to be monitored closely and may necessitate mitigating measures. There are different strategies to deal with these two undesirable effects: The neutron emission may be reduced to some extent all around the core or just at the 'hot spots' of RPV embrittlement by tailored core loading patterns. A higher absorption rate of neutrons may also be achieved by a larger water gap between the core and the RPV. In this paper the inter-relations between the distribution of neutron flux, core geometry, core loading strategy, RPV embrittlement and its surveillance are discussed at first. Then the different strategies followed by the German and French operators are described. Finally the conclusions will highlight the communalities and differences between these strategies as different approaches to the same problem of safety as well as economy. (authors)

  6. Neurilemmoma showing a unique growth pattern in the lateral chest wall: both inside and outside the thoracic cavity.

    Science.gov (United States)

    Jun Ahn, Sun; Joo Park, Kyung; Sung Sun, Joo; Choi, Ho; Hee Lee, Yong

    2014-01-01

    We report the first case of the intercostal neurilemmoma showing a unique growth pattern in the lateral chest wall (both inside and outside the thoracic cavity). Usually, intrathoracic neurilemmoma is found in the posterior mediastinum and bulge from the inner surface of the bony thorax toward the thoracic cavity. This unique growing pattern of neurilemmoma arising from intercostal nerve was clearly demonstrated by computed tomography and ultrasonography.

  7. Is the wood of spruces affected by immissions liable to show alterations of the cell wall structure

    Energy Technology Data Exchange (ETDEWEB)

    Sachsse, H.; Hapla, F.

    The results of investigations so far conducted showed no alterations of technological consequence either in the chemical composition or in the anatomical structure of the wood from trees affected by immissions. For the first time now the packing density of tracheid cell walls in spruces damaged by immissions is investigated by means of microscopic linear analysis. No significant difference was found as compared to the packing density of wood having been formed free of immission influence.

  8. Carboxylated short single-walled carbon nanotubes but not plain and multi-walled short carbon nanotubes show in vitro genotoxicity.

    Science.gov (United States)

    Mrakovcic, Maria; Meindl, Claudia; Leitinger, Gerd; Roblegg, Eva; Fröhlich, Eleonore

    2015-03-01

    Long carbon nanotubes (CNTs) resemble asbestos fibers due to their high length to diameter ratio and they thus have genotoxic effects. Another parameter that might explain their genotoxic effects is contamination with heavy metal ions. On the other hand, short (1-2 µm) CNTs do not resemble asbestos fibers, and, once purified from contaminations, they might be suitable for medical applications. To identify the role of fiber thickness and surface properties on genotoxicity, well-characterized short pristine and carboxylated single-walled (SCNTs) and multi-walled (MCNTs) CNTs of different diameters were studied for cytotoxicity, the cell's response to oxidative stress (immunoreactivity against hemoxygenase 1 and glutathione levels), and in a hypoxanthine guanine phosphoribosyltransferase (HPRT) assay using V79 chinese hamster fibroblasts and human lung adenocarcinoma A549 cells. DNA repair was demonstrated by measuring immunoreactivity against activated histone H2AX protein. The number of micronuclei as well as the number of multinucleated cells was determined. CNTs acted more cytotoxic in V79 than in A549 cells. Plain and carboxylated thin (oxidative stress. Multi-walled CNTs did not cause HPRT mutation, micronucleus formation, DNA damage, interference with cell division, and oxidative stress. Carboxylated, but not plain, SCNTs showed indication for in vitro DNA damage according to increase of H2AX-immunoreactive cells and HPRT mutation. Although short CNTs presented a low in vitro genotoxicity, functionalization of short SCNTs can render these particles genotoxic. © The Author 2014. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  9. Bioreactor rotating wall vessel

    Science.gov (United States)

    2001-01-01

    The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Cell constructs grown in a rotating bioreactor on Earth (left) eventually become too large to stay suspended in the nutrient media. In the microgravity of orbit, the cells stay suspended. Rotation then is needed for gentle stirring to replenish the media around the cells.

  10. wall

    Directory of Open Access Journals (Sweden)

    Irshad Kashif

    2016-01-01

    Full Text Available Maintaining indoor climatic conditions of buildings compatible with the occupant comfort by consuming minimum energy, especially in a tropical climate becomes a challenging problem for researchers. This paper aims to investigate this problem by evaluating the effect of different kind of Photovoltaic Trombe wall system (PV-TW on thermal comfort, energy consumption and CO2 emission. A detailed simulation model of a single room building integrated with PV-TW was modelled using TRNSYS software. Results show that 14-35% PMV index and 26-38% PPD index reduces as system shifted from SPV-TW to DGPV-TW as compared to normal buildings. Thermal comfort indexes (PMV and PPD lie in the recommended range of ASHARE for both DPV-TW and DGPV-TW except for the few months when RH%, solar radiation intensity and ambient temperature were high. Moreover PVTW system significantly reduces energy consumption and CO2 emission of the building and also 2-4.8 °C of temperature differences between indoor and outdoor climate of building was examined.

  11. Simulated Microgravity Regulates Gene Transcript Profiles of 2T3 Preosteoblasts: Comparison of the Random Positioning Machine and the Rotating Wall Vessel Bioreactor

    Science.gov (United States)

    Patel, Mamta J.; Liu, Wenbin; Sykes, Michelle C.; Ward, Nancy E.; Risin, Semyon A.; Risin, Diana; Hanjoong, Jo

    2007-01-01

    Microgravity of spaceflight induces bone loss due in part to decreased bone formation by osteoblasts. We have previously examined the microgravity-induced changes in gene expression profiles in 2T3 preosteoblasts using the Random Positioning Machine (RPM) to simulate microgravity conditions. Here, we hypothesized that exposure of preosteoblasts to an independent microgravity simulator, the Rotating Wall Vessel (RWV), induces similar changes in differentiation and gene transcript profiles, resulting in a more confined list of gravi-sensitive genes that may play a role in bone formation. In comparison to static 1g controls, exposure of 2T3 cells to RWV for 3 days inhibited alkaline phosphatase activity, a marker of differentiation, and downregulated 61 genes and upregulated 45 genes by more than two-fold as shown by microarray analysis. The microarray results were confirmed with real time PCR for downregulated genes osteomodulin, bone morphogenic protein 4 (BMP4), runx2, and parathyroid hormone receptor 1. Western blot analysis validated the expression of three downregulated genes, BMP4, peroxiredoxin IV, and osteoglycin, and one upregulated gene peroxiredoxin I. Comparison of the microarrays from the RPM and the RWV studies identified 14 gravi-sensitive genes that changed in the same direction in both systems. Further comparison of our results to a published database showing gene transcript profiles of mechanically loaded mouse tibiae revealed 16 genes upregulated by the loading that were shown to be downregulated by RWV and RPM. These mechanosensitive genes identified by the comparative studies may provide novel insights into understanding the mechanisms regulating bone formation and potential targets of countermeasure against decreased bone formation both in astronauts and in general patients with musculoskeletal disorders.

  12. High-resolution 3D coronary vessel wall imaging with near 100% respiratory efficiency using epicardial fat tracking: reproducibility and comparison with standard methods.

    Science.gov (United States)

    Scott, Andrew D; Keegan, Jennifer; Firmin, David N

    2011-01-01

    To quantitatively assess the performance and reproducibility of 3D spiral coronary artery wall imaging with beat-to-beat respiratory-motion-correction (B2B-RMC) compared to navigator gated 2D spiral and turbo-spin-echo (TSE) acquisitions. High-resolution (0.7 × 0.7 mm) cross-sectional right coronary wall acquisitions were performed in 10 subjects using four techniques (B2B-RMC 3D spiral with alternate (2RR) and single (1RR) R-wave gating, navigator-gated 2D spiral (2RR) and navigator-gated 2D TSE (2RR)) on two occasions. Wall thickness measurements were compared with repeated measures analysis of variance (ANOVA). Reproducibility was assessed with the intraclass correlation coefficient (ICC). In all, 91% (73/80) of acquisitions were successful (failures: four TSE, two 3D spiral (1RR) and one 3D spiral (2RR)). Respiratory efficiency of the B2B-RMC was less variable and substantially higher than for navigator gating (99.6 ± 1.2% vs. 39.0 ± 7.5%, P B2B-RMC permits coronary vessel wall assessment over multiple thin contiguous slices in a clinically feasible duration. Excellent reproducibility of the technique potentially enables studies of disease progression/regression. Copyright © 2010 Wiley-Liss, Inc.

  13. Modeling the microclimate inside a vessel in in vitro culture : vessel ...

    African Journals Online (AJOL)

    Numerical simulations show that variations in vessel internal humidity was sensitive to transfer coefficient, climatic conditions within the growth chamber, evaporation and condensation of water vapor on the walls of the vessel. The variations in water vapor pressure deficits (VPD) (low during the nyctiperiod and high during ...

  14. An in vivo pilot study of a microporous thin film nitinol-covered stent to assess the effect of porosity and pore geometry on device interaction with the vessel wall.

    Science.gov (United States)

    Chun, Youngjae; Kealey, Colin P; Levi, Daniel S; Rigberg, David A; Chen, Yanfei; Tillman, Bryan W; Mohanchandra, K P; Shayan, Mahdis; Carman, Gregory P

    2017-03-01

    Sputter-deposited thin film nitinol constructs with various micropatterns were fabricated to evaluate their effect on the vessel wall in vivo when used as a covering for commercially available stents. Thin film nitinol constructs were used to cover stents and deployed in non-diseased swine arteries. Swine were sacrificed after approximately four weeks and the thin film nitinol-covered stents were removed for histopathologic evaluation. Histopathology revealed differences in neointimal thickness that correlated with the thin film nitinol micropattern. Devices covered with thin film nitinol with a lateral × vertical length = 20 × 40 µm diamond pattern had minimal neointimal growth with well-organized cell architecture and little evidence of ongoing inflammation. Devices covered with thin film nitinol with smaller fenestrations exhibited a relatively thick neointimal layer with inflammation and larger fenestrations showed migration of inflammatory and smooth muscle cells through the micro fenestrations. This "proof-of-concept" study suggests that there may be an ideal thin film nitinol porosity and pore geometry to encourage endothelialization and incorporation of the device into the vessel wall. Future work will be needed to determine the optimal pore size and geometry to minimize neointimal proliferation and in-stent stenosis.

  15. Effects of Simulated Microgravity on Otolith Growth of Larval Zebrafish using a Rotating-Wall Vessel: Appropriate Rotation Speed and Fish Developmental Stage

    Science.gov (United States)

    Li, Xiaoyan; Anken, Ralf; Liu, Liyue; Wang, Gaohong; Liu, Yongding

    2017-02-01

    Stimulus dependence is a general feature of developing animal sensory systems. In this respect, it has extensively been shown earlier that fish inner ear otoliths can act as test masses as their growth is strongly affected by altered gravity such as hypergravity obtained using centrifuges, by (real) microgravity achieved during spaceflight or by simulated microgravity using a ground-based facility. Since flight opportunities are scarce, ground-based simulators of microgravity, using a wide variety of physical principles, have been developed to overcome this shortcoming. Not all of them, however, are equally well suited to provide functional weightlessness from the perspective of the biosystem under evaluation. Therefore, the range of applicability of a particular simulator has to be extensively tested. Earlier, we have shown that a Rotating-Wall Vessel (RWV) can be used to provide simulated microgravity for developing Zebrafish regarding the effect of rotation on otolith development. In the present study, we wanted to find the most effective speed of rotation and identify the appropriate developmental stage of Zebrafish, where effects are the largest, in order to provide a methodological basis for future in-depth analyses dedicated to the physiological processes underlying otolith growth at altered gravity. Last not least, we compared data on the effect of simulated microgravity on the size versus the weight of otoliths, since the size usually is measured in related studies due to convenience, but the weight more accurately approximates the physical capacity of an otolith. Maintaining embryos at 10 hours post fertilization for three days in the RWV, we found that 15 revolutions per minute (rpm) yielded the strongest effects on otolith growth. Maintenance of Zebrafish staged at 10 hpf, 1 day post fertilization (dpf), 4 dpf, 7 dpf and 14 dpf for three days at 15 rpm resulted in the most prominent effects in 7 dpf larvae. Weighing versus measuring the size of otoliths

  16. In-vessel calibration of the imaging diagnostics for the real-time protection of the JET ITER-like wall

    Energy Technology Data Exchange (ETDEWEB)

    Huber, V., E-mail: V.Huber@fz-juelich.de [Forschungszentrum Jülich GmbH, Supercomputing Centre, 52425 Jülich (Germany); Huber, A.; Mertens, Ph.; Sergienko, G. [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung—Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich (Germany); Kinna, D.; Balboa, I.; Collins, S.; Conway, N.; Maggi, C. F.; Matthews, G. F.; Meigs, A. G.; Price, M.; Silburn, S.; Zastrow, K.-D. [CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Drewelow, P. [MPI für Plasmaphysik, Greifswald (Germany); Wynn, A. [York Plasma Institute, University of York, Heslington, York YO10 5DD (United Kingdom)

    2016-11-15

    The in situ absolute calibration of the JET real-time protection imaging system has been performed for the first time by means of radiometric light source placed inside the JET vessel and operated by remote handling. High accuracy of the calibration is confirmed by cross-validation of the near infrared (NIR) cameras against each other, with thermal IR cameras, and with the beryllium evaporator, which lead to successful protection of the JET first wall during the last campaign. The operation temperature ranges of NIR protection cameras for the materials used on JET are Be 650-1600 °C, W coating 600-1320 °C, and W 650-1500 °C.

  17. Whole-brain vessel wall MRI: A parameter tune-up solution to improve the scan efficiency of three-dimensional variable flip-angle turbo spin-echo.

    Science.gov (United States)

    Yang, Qi; Deng, Zixin; Bi, Xiaoming; Song, Shlee S; Schlick, Konrad H; Gonzalez, Nestor R; Li, Debiao; Fan, Zhaoyang

    2017-09-01

    To propose and evaluate a parameter tune-up solution to expedite a three-dimensional (3D) variable-flip-angle turbo spin-echo (TSE) sequence for whole-brain intracranial vessel wall (IVW) imaging. Elliptical k-space sampling and prolonged echo train length (ETL), were used to expedite a 3D variable-flip-angle TSE-based sequence. To compensate for the potential loss in vessel wall signal, optimal combination of prescribed T 2 and ETL was experimentally investigated on 22 healthy volunteers at 3 Tesla. The optimized protocol (7-8 min) was then compared with a previous protocol (reference protocol, 11-12 min) in terms of signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), vessel wall sharpness, and wall delineation quality on a 4-point scale (0:poor; 3:excellent) in 10 healthy volunteers. A pilot study of five patients was performed and lesion delineation score was used to demonstrate the diagnostic quality. A protocol with ETL = 52 and prescribed T 2  = 170 ms was deemed an optimized one, which, compared with the reference protocol, provided significantly improved wall SNR (12.0 ± 1.3 versus 10.0 ± 1.1; P = 0.002), wall-lumen CNR (9.7 ± 1.2 versus 8.0 ± 0.9; P = 0.002), wall-CSF CNR (2.8 ± 1.0 versus 1.7 ± 1.0; P = 0.026), similar vessel wall sharpness at both inner (1.59 ± 0.18 versus 1.58 ± 0.14, P = 0.87) and outer (1.71 ± 0.25 versus 1.83 ± 0.30; P = 0.18) boundaries, and comparable vessel wall delineation score for individual segments (1.95-3; P > 0.06). In all patients, atherosclerotic plaques (10) or wall dissection (5) were identified with a delineation score of 3 or 2. A parameter tune-up solution can accelerate 3D variable-flip-angle TSE acquisitions, particularly allowed for expedited whole-brain IVW imaging with preserved wall delineation quality. 2. Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:751-757. © 2017 International Society for Magnetic

  18. Breast arterial calcification and risk of carotid atherosclerosis: Focusing on the preferentially affected layer of the vessel wall

    Energy Technology Data Exchange (ETDEWEB)

    Sedighi, Nahid, E-mail: nsedighi@sina.tums.ac.ir [Department of Radiology, Shariati Hospital, Tehran University of Medical Sciences. North Kargar Ave., Tehran 14114 (Iran, Islamic Republic of); Radmard, Amir Reza, E-mail: radmard@ams.ac.ir [Department of Radiology, Shariati Hospital, Tehran University of Medical Sciences. North Kargar Ave., Tehran 14114 (Iran, Islamic Republic of); Radmehr, Ali, E-mail: radmehr@sina.tums.ac.ir [Department of Radiology, Shariati Hospital, Tehran University of Medical Sciences. North Kargar Ave., Tehran 14114 (Iran, Islamic Republic of); Hashemi, Pari, E-mail: phtums@yahoo.com [Department of Radiology, Shariati Hospital, Tehran University of Medical Sciences. North Kargar Ave., Tehran 14114 (Iran, Islamic Republic of); Hajizadeh, Abdolmahmoud, E-mail: mroomezi@yahoo.com [Department of Radiology, Shariati Hospital, Tehran University of Medical Sciences. North Kargar Ave., Tehran 14114 (Iran, Islamic Republic of); Taheri, Amir Pejman Hashemi, E-mail: hashemip@sina.tums.ac.ir [Department of Radiology, Shariati Hospital, Tehran University of Medical Sciences. North Kargar Ave., Tehran 14114 (Iran, Islamic Republic of)

    2011-08-15

    Objective: To assess the relationship between breast arterial calcification (BAC) detected on screening mammography and atherosclerosis of carotid arteries considering the most likely involved layer of the arterial wall. Materials and methods: A total of 537 consecutive women who underwent screening mammography were enrolled in this study. Seventy-nine subjects having BAC, aged 46-75 years, and 125 age-matched controls from those without BAC were selected for ultrasound examination of carotid arteries assessing intima-media thickness (IMT) and plaque presence. Participants were divided into three groups of risk including, low-risk: IMT < 0.6 mm without plaque, medium-risk: 0.6 mm {<=} IMT {<=} 0.8 mm without plaque and high-risk: IMT > 0.8 mm and/or plaque. Risk factors for atherosclerosis were obtained from medical records for independent effects. Results: BAC was present in 14.7% of mammograms. According to multivariable logistic regression analyses, significant association was identified between the carotid atherosclerosis risk and presence of BAC. Compared to women with IMT < 0.6 mm, those with 0.6 mm {<=} IMT{<=} 0.8 mm and IMT > 0.8 mm had OR (95% CI) of 4.88 (1.47-16.16) and 23.36 (4.54-120.14), respectively. The OR (95% CI) for carotid plaque was 3.13 (1.3-7.57). There was no interaction between IMT category and plaque. Significant associations were also detected with postmenopausal duration (P = 0.02) and hypertension (P = 0.004). Conclusion: The risk of carotid atherosclerosis increases with the presence of BAC. Women with BAC are more likely to have thicker IMT than plaque, which could be attributed to the preferentially similar affected layer of media causing thick IMT rather than plaque.

  19. Investigation of radial shear in the wall-base juncture of a 1:4 scale prestressed concrete containment vessel model

    Energy Technology Data Exchange (ETDEWEB)

    Dameron, R.A.; Rashid, Y.R. [ANATECH Corp., San Diego, CA (United States); Luk, V.K.; Hessheimer, M.F. [Sandia National Labs., Albuquerque, NM (United States)

    1998-04-01

    Construction of a prestressed concrete containment vessel (PCCV) model is underway as part of a cooperative containment research program at Sandia National Laboratories. The work is co-sponsored by the Nuclear Power Engineering Corporation (NUPEC) of Japan and US Nuclear Regulatory Commission (NRC). Preliminary analyses of the Sandia 1:4 Scale PCCV Model have determined axisymmetric global behavior and have estimated the potential for failure in several areas, including the wall-base juncture and near penetrations. Though the liner tearing failure mode has been emphasized, the assumption of a liner tearing failure mode is largely based on experience with reinforced concrete containments. For the PCCV, the potential for shear failure at or near the liner tearing pressure may be considerable and requires detailed investigation. This paper examines the behavior of the PCCV in the region most susceptible to a radial shear failure, the wall-basemat juncture region. Prediction of shear failure in concrete structures is a difficult goal, both experimentally and analytically. As a structure begins to deform under an applied system of forces that produce shear, other deformation modes such as bending and tension/compression begin to influence the response. Analytically, difficulties lie in characterizing the decrease in shear stiffness and shear stress and in predicting the associated transfer of stress to reinforcement as cracks become wider and more extensive. This paper examines existing methods for representing concrete shear response and existing criteria for predicting shear failure, and it discusses application of these methods and criteria to the study of the 1:4 scale PCCV.

  20. Fluid-structure interaction analysis on the effect of vessel wall hypertrophy and stiffness on the blood flow in carotid artery bifurcation

    Science.gov (United States)

    Lee, Sang Hoon; Choi, Hyoung Gwon; Yoo, Jung Yul

    2012-11-01

    The effect of artery wall hypertrophy and stiffness on the flow field is investigated using three-dimensional finite element method for simulating the blood flow. To avoid the complexity due to the necessity of additional mechanical constraints, we use the combined formulation which includes both the fluid and structural equations of motion into single coupled variational equation. A P2P1 Galerkin finite element method is used to solve the Navier-Stokes equations for fluid flow and arbitrary Lagrangian-Eulerian formulation is used to achieve mesh movement. The Newmark method is employed for solving the dynamic equilibrium equations for linear elastic solid mechanics. The pulsatile, incompressible flows of Newtonian fluids constrained in the flexible wall are analyzed with Womersley velocity profile at the inlet and constant pressure at the outlet. The study shows that the stiffness of carotid artery wall affects significantly the flow phenomena during the pulse cycle. Similarly, it is found that the flow field is also strongly influenced by wall hypertrophy. This work was supported by Mid-career Researcher Program and Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2009-0079936 & 2011-0029613).

  1. 3D rotating wall vessel and 2D cell culture of four veterinary virus pathogens: A comparison of virus yields, portions of infectious particles and virus growth curves.

    Science.gov (United States)

    Malenovská, Hana

    2016-02-01

    Only very few comparative studies have been performed that evaluate general trends of virus growth under 3D in comparison with 2D cell culture conditions. The aim of this study was to investigate differences when four animal viruses are cultured in 2D and 3D. Suid herpesvirus 1 (SuHV-1), Vesicular stomatitis virus (VSIV), Bovine adenovirus (BAdV) and Bovine parainfluenza 3 virus (BPIV-3) were cultivated in 3D rotating wall vessels (RWVs) and conventional 2D cultures. The production of virus particles, the portion of infectious particles, and the infectious growth curves were compared. For all viruses, the production of virus particles (related to cell density), including the non-infectious ones, was lower in 3D than in 2D culture. The production of only infectious particles was significantly lower in BAdV and BPIV-3 in 3D cultures in relation to cell density. The two cultivation approaches resulted in significantly different virus particle-to-TCID50 ratios in three of the four viruses: lower in SuHV-1 and BPIV-3 and higher in BAdV in 3D culture. The infectious virus growth rates were not significantly different in all viruses. Although 3D RWV culture resulted in lower production of virus particles compared to 2D systems, the portion of infectious particles was higher for some viruses. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. In Vivo Clearance of Alpha-1 Acid Glycoprotein Is Influenced by the Extent of Its N-Linked Glycosylation and by Its Interaction with the Vessel Wall

    Directory of Open Access Journals (Sweden)

    Teresa R. McCurdy

    2012-01-01

    Full Text Available Alpha-1 acid glycoprotein (AGP is a highly glycosylated plasma protein that exerts vasoprotective effects. We hypothesized that AGP’s N-linked glycans govern its rate of clearance from the circulation, and followed the disappearance of different forms of radiolabeled human AGP from the plasma of rabbits and mice. Enzymatic deglycosylation of human plasma-derived AGP (pdAGP by Peptide: N-Glycosidase F yielded a mixture of differentially deglycosylated forms (PNGase-AGP, while the introduction of five Asn to Gln mutations in recombinant Pichia pastoris-derived AGP (rAGP-N(5Q eliminated N-linked glycosylation. PNGase-AGP was cleared from the rabbit circulation 9-fold, and rAGP-N(5Q, 46-fold more rapidly than pdAGP, primarily via a renal route. Pichia pastoris-derived wild-type rAGP differed from pdAGP in expressing mannose-terminated glycans, and, like neuraminidase-treated pdAGP, was more rapidly removed from the rabbit circulation than rAGP-N(5Q. Systemic hyaluronidase treatment of mice transiently decreased pdAGP clearance. AGP administration to mice reduced vascular binding of hyaluronic acid binding protein in the liver microcirculation and increased its plasma levels. Our results support a critical role of N-linked glycosylation of AGP in regulating its in vivo clearance and an influence of a hyaluronidase-sensitive component of the vessel wall on its transendothelial passage.

  3. Endovascular repair of arterial iliac vessel wall lesions with a self-expandable nitinol stent graft system.

    Directory of Open Access Journals (Sweden)

    Birger Mensel

    Full Text Available To assess the therapeutic outcome after endovascular repair of iliac arterial lesions (IALs using a self-expandable Nitinol stent graft system.Between July 2006 and March 2013, 16 patients (13 males, mean age: 68 years with a self-expandable Nitinol stent graft. A total of 19 lesions were treated: nine true aneurysms, two anastomotic aneurysms, two dissections, one arteriovenous fistula, two type 1B endoleaks after endovascular aneurysm repair, one pseudoaneurysm, and two perforations after angioplasty. Pre-, intra-, and postinterventional imaging studies and the medical records were analyzed for technical and clinical success and postinterventional complications.The primary technical and clinical success rate was 81.3% (13/16 patients and 75.0% (12/16, respectively. Two patients had technical failure due to persistent type 1A endoleak and another patient due to acute stent graft thrombosis. One patient showed severe stent graft kinking on the first postinterventional day. In two patients, a second intervention was performed. The secondary technical and clinical success rate was 87.5% (14/16 and 93.8% (15/16. The minor complication rate was 6.3% (patient with painful hematoma at the access site. The major complication rate was 6.3% (patient with ipsilateral deep vein thrombosis. During median follow-up of 22.4 months, an infection of the aneurysm sac in one patient and a stent graft thrombosis in another patient were observed.Endovascular repair of various IALs with a self-expandable Nitinol stent graft is safe and effective.

  4. Effects of High-sugar and High-fat Diet on Fat Deposition and Blood Vessel Wall on Sprague Dawley Rats Liver

    Directory of Open Access Journals (Sweden)

    Vera Citra Setiawan Hoei

    2013-11-01

    Full Text Available People nowadays tend to consume more fast food and sweetened beverages. These foods usually contain high amount sugar and fat that have effects on the body including liver.This study was conducted to explore the effects of extensive intake of sugar and fat on blood glucose and  cholesterol level as well as changes in liver. Research was conducted with experimental method using 20 Sprague Dawley rats which were divided into 4 groups; 2 controls and 2 treatments. Rats were given 5 ml sugar or lard alternatively every 2 consecutive days for 1-month and 2-month respectively. Data was retrieved include blood glucose and cholesterol level, fatty liver percentage and blood vessel thickening after intervention through HE staining. The results showed that both 1-month and 2-month intervention group has significant increase in blood glucose and cholesterol level. However, the enhancement of fatty liver percentage and number of thickened blood vessels (p<0.05 were only foundsignificant (p<0.05 in 1-month intervention group.  We concluded that high intake of sugar and fat within 1-monthintervention have significant effects on the rat body including liver. Nevertheless, it was not found significant in 2-months intervention. Further studies are still needed to analyze this incongruent result.Key words: high-sugar diet, high-fat diet, fatty liver, atherosclerosis 

  5. Collapsible Cryogenic Storage Vessel Project

    Science.gov (United States)

    Fleming, David C.

    2002-01-01

    Collapsible cryogenic storage vessels may be useful for future space exploration missions by providing long-term storage capability using a lightweight system that can be compactly packaged for launch. Previous development efforts have identified an 'inflatable' concept as most promising. In the inflatable tank concept, the cryogen is contained within a flexible pressure wall comprised of a flexible bladder to contain the cryogen and a fabric reinforcement layer for structural strength. A flexible, high-performance insulation jacket surrounds the vessel. The weight of the tank and the cryogen is supported by rigid support structures. This design concept is developed through physical testing of a scaled pressure wall, and through development of tests for a flexible Layered Composite Insulation (LCI) insulation jacket. A demonstration pressure wall is fabricated using Spectra fabric for reinforcement, and burst tested under noncryogenic conditions. An insulation test specimens is prepared to demonstrate the effectiveness of the insulation when subject to folding effects, and to examine the effect of compression of the insulation under compressive loading to simulate the pressure effect in a nonrigid insulation blanket under the action atmospheric pressure, such as would be seen in application on the surface of Mars. Although pressure testing did not meet the design goals, the concept shows promise for the design. The testing program provides direction for future development of the collapsible cryogenic vessel concept.

  6. Vessel Operating Units (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains data for vessels that are greater than five net tons and have a current US Coast Guard documentation number. Beginning in1979, the NMFS...

  7. What are the residual stresses doing in our blood vessels?

    Science.gov (United States)

    Fung, Y C

    1991-01-01

    We show that the residual strain and stress in the blood vessels are not zero, and that the zero-stress state of a blood vessel consists of open-sector segments whose opening angles vary along the longitudinal axis of the vessel. When the homeostatic state of the blood vessel is changed, e.g., by a sudden hypertension, the opening angle will change. The time constant of the opening angle change is a few hours (e.g., in the pulmonary artery) or a few days (e.g., in the aorta). From a kinematic point of view, a change of opening angle is a bending of the blood vessel wall, which is caused by a nonuniformly distributed residual strain. From a mechanics point of view, changes of blood pressure and residual strain cause change of stress in the blood vessel wall. Correlating the stress with the change of residual strain yields a fundamental biological law relating the rate of growth or resorption of tissue with the stress in the tissue. Thus, residual stresses are related to the remodeling of the blood vessel wall. Our blood vessel remodels itself when stress changes. The stress-growth law provides a biomechanical foundation for tissue engineering.

  8. Optimizing {sup 18}F-FDG PET/CT imaging of vessel wall inflammation: the impact of {sup 18}F-FDG circulation time, injected dose, uptake parameters, and fasting blood glucose levels

    Energy Technology Data Exchange (ETDEWEB)

    Bucerius, Jan [Icahn School of Medicine at Mount Sinai, Translational and Molecular Imaging Institute, One Gustave L. Levy Place, P.O. Box 1234, New York, NY (United States); Mount Sinai School of Medicine, Department of Radiology, New York, NY (United States); Maastricht University Medical Center, Department of Nuclear Medicine, Maastricht (Netherlands); Maastricht University Medical Center, Cardiovascular Research Institute Maastricht (CARIM), Maastricht (Netherlands); University Hospital, RWTH Aachen, Department of Nuclear Medicine, Aachen (Germany); Mani, Venkatesh; Fayad, Zahi A. [Icahn School of Medicine at Mount Sinai, Translational and Molecular Imaging Institute, One Gustave L. Levy Place, P.O. Box 1234, New York, NY (United States); Mount Sinai School of Medicine, Department of Radiology, New York, NY (United States); Mount Sinai School of Medicine, Department of Cardiology, Zena and Michael A. Weiner Cardiovascular Institute and Marie-Josee and Henry R. Kravis Cardiovascular Health Center, New York, NY (United States); Moncrieff, Colin [Icahn School of Medicine at Mount Sinai, Translational and Molecular Imaging Institute, One Gustave L. Levy Place, P.O. Box 1234, New York, NY (United States); Mount Sinai School of Medicine, Department of Radiology, New York, NY (United States); Machac, Josef [Mount Sinai School of Medicine, Division of Nuclear Medicine, Department of Radiology, New York, NY (United States); Fuster, Valentin [Mount Sinai School of Medicine, Department of Cardiology, Zena and Michael A. Weiner Cardiovascular Institute and Marie-Josee and Henry R. Kravis Cardiovascular Health Center, New York, NY (United States); The Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid (Spain); Farkouh, Michael E. [Mount Sinai School of Medicine, Department of Cardiology, Zena and Michael A. Weiner Cardiovascular Institute and Marie-Josee and Henry R. Kravis Cardiovascular Health Center, New York, NY (United States); Mount Sinai School of Medicine, Cardiovascular Imaging Clinical Trials Unit, New York, NY (United States); Tawakol, Ahmed [Massachusetts General Hospital, Harvard University, Cardiac MR PET CT Program, Boston, MA (United States); Rudd, James H.F. [Cambridge University, Division of Cardiovascular Medicine, Cambridge (United Kingdom)

    2014-02-15

    {sup 18}F-FDG PET is increasingly used for imaging of vessel wall inflammation. However, limited data are available on the impact of methodological variables, i.e. prescan fasting glucose, FDG circulation time and injected FDG dose, and of different FDG uptake parameters, in vascular FDG PET imaging. Included in the study were 195 patients who underwent vascular FDG PET/CT of the aorta and the carotids. Arterial standardized uptake values ({sub mean}SUV{sub max}), target-to-background ratios ({sub mean}TBR{sub max}) and FDG blood-pool activity in the superior vena cava (SVC) and the jugular veins (JV) were quantified. Vascular FDG uptake values classified according to the tertiles of prescan fasting glucose levels, the FDG circulation time, and the injected FDG dose were compared using ANOVA. Multivariate regression analyses were performed to identify the potential impact of all variables described on the arterial and blood-pool FDG uptake. Tertile analyses revealed FDG circulation times of about 2.5 h and prescan glucose levels of less than 7.0 mmol/l, showing a favorable relationship between arterial and blood-pool FDG uptake. FDG circulation times showed negative associations with aortic{sub mean}SUV{sub max} values as well as SVC and JV FDG blood-pool activity, but positive correlations with aortic and carotid{sub mean}TBR{sub max} values. Prescan glucose levels were negatively associated with aortic and carotid{sub mean}TBR{sub max} and carotid{sub mean}SUV{sub max} values, but were positively correlated with SVC blood-pool uptake. The injected FDG dose failed to show any significant association with vascular FDG uptake. FDG circulation times and prescan blood glucose levels significantly affect FDG uptake in the aortic and carotid walls and may bias the results of image interpretation in patients undergoing vascular FDG PET/CT. The injected FDG dose was less critical. Therefore, circulation times of about 2.5 h and prescan glucose levels less than 7.0 mmol

  9. Studies on in-vessel debris coolability in ALPHA program

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, Yu; Yamano, Norihiro; Moriyama, Kiyofumi [Japan Atomic Energy Research Institute, Ibaraki-ken (Japan)] [and others

    1997-02-01

    In-vessel debris coolability experiments have been performed in ALPHA Program at JAERI. Aluminum oxide (Al{sub 2}O{sub 3}) produced by a thermite reaction was applied as a debris simulant. Two scoping experiments using approximately 30 kg or 50 kg of Al{sub 2}O{sub 3} were conducted. In addition to post-test observations, temperature histories of the debris simulant and the lower head experimental vessel were evaluated. Rapid temperature reduction observed on the outer surface of the experimental vessel may imply that water penetration into a gap between the solidified debris and the experimental vessel occurred resulting in an effective cooling of once heated vessel wall. Preliminary measurement of a gap width was made with an ultrasonic device. Signals to show the existence of gaps, ranging from 0.7 mm to 1.4 mm, were detected at several locations.

  10. Estimate of radiation-induced steel embrittlement in the BWR core shroud and vessel wall from reactor-grade MOX/UOX fuel for the nuclear power plant at Laguna Verde, Veracruz, Mexico

    Science.gov (United States)

    Vickers, Lisa Rene

    The government of Mexico has expressed interest to utilize the Laguna Verde boiling water reactor (BWR) nuclear power plant for the disposition of reprocessed spent uranium oxide (UOX) fuel in the form of reactor-grade mixed-oxide (MOX) fuel. MOX fuel would replace spent UOX fuel as a fraction in the core from 18--30% depending on the fuel loading cycle. MOX fuel is expected to increase the neutron fluence, flux, fuel centerline temperature, reactor core pressure, and yield higher energy neutrons. There is concern that a core with a fraction of MOX fuel (i.e., increased 239Pu wt%) would increase the radiation-induced steel embrittlement within the core shroud and vessel wall as compared to only conventional, enriched UOX fuel in the core. The evaluation of radiation-induced steel embrittlement within the core shroud and vessel wall is a concern because of the potentially adverse affect to plant and public safety, environment, and operating life of the reactor. This dissertation provides computational results of the neutron fluence, flux, energy spectrum, and radiation damage displacements per atom per second (dpa-s-1) in steel within the core shroud and vessel wall of the Laguna Verde Unit 1 BWR. The results were computed using the nuclear data processing code NJOY99 and the continuous energy Monte Carlo Neutral Particle transport code MCNP4B. The MCNP4B model of the reactor core was for maximum core loading fractions of ⅓ MOX and ⅔ UOX reactor-grade fuel in an equilibrium core. The primary conclusion of this dissertation was that the addition of the maximum fraction of ⅓ MOX fuel to the LV1 BWR core did significantly accelerate the radiation-induced steel embrittlement such that without mitigation of steel embrittlement by periodic thermal annealing or reduction in operating parameters such as, neutron fluence, core temperature and pressure, it posed a potentially adverse affect to the plant and public safety, environment, and operating life of the reactor.

  11. Optimal Branching Structure of Fluidic Networks with Permeable Walls

    Directory of Open Access Journals (Sweden)

    Vinicius R. Pepe

    2017-01-01

    Full Text Available Biological and engineering studies of Hess-Murray’s law are focused on assemblies of tubes with impermeable walls. Blood vessels and airways have permeable walls to allow the exchange of fluid and other dissolved substances with tissues. Should Hess-Murray’s law hold for bifurcating systems in which the walls of the vessels are permeable to fluid? This paper investigates the fluid flow in a porous-walled T-shaped assembly of vessels. Fluid flow in this branching flow structure is studied numerically to predict the configuration that provides greater access to the flow. Our findings indicate, among other results, that an asymmetric flow (i.e., breaking the symmetry of the flow distribution may occur in this symmetrical dichotomous system. To derive expressions for the optimum branching sizes, the hydraulic resistance of the branched system is computed. Here we show the T-shaped assembly of vessels is only conforming to Hess-Murray’s law optimum as long as they have impervious walls. Findings also indicate that the optimum relationship between the sizes of parent and daughter tubes depends on the wall permeability of the assembled tubes. Our results agree with analytical results obtained from a variety of sources and provide new insights into the dynamics within the assembly of vessels.

  12. Cholinergic innervation of human mesenteric lymphatic vessels.

    Science.gov (United States)

    D'Andrea, V; Bianchi, E; Taurone, S; Mignini, F; Cavallotti, C; Artico, M

    2013-11-01

    The cholinergic neurotransmission within the human mesenteric lymphatic vessels has been poorly studied. Therefore, our aim is to analyse the cholinergic nerve fibres of lymphatic vessels using the traditional enzymatic techniques of staining, plus the biochemical modifications of acetylcholinesterase (AChE) activity. Specimens obtained from human mesenteric lymphatic vessels were subjected to the following experimental procedures: 1) drawing, cutting and staining of tissues; 2) staining of total nerve fibres; 3) enzymatic staining of cholinergic nerve fibres; 4) homogenisation of tissues; 5) biochemical amount of proteins; 6) biochemical amount of AChE activity; 6) quantitative analysis of images; 7) statistical analysis of data. The mesenteric lymphatic vessels show many AChE positive nerve fibres around their wall with an almost plexiform distribution. The incubation time was performed at 1 h (partial activity) and 6 h (total activity). Moreover, biochemical dosage of the same enzymatic activity confirms the results obtained with morphological methods. The homogenates of the studied tissues contain strong AChE activity. In our study, the lymphatic vessels appeared to contain few cholinergic nerve fibres. Therefore, it is expected that perivascular nerve stimulation stimulates cholinergic nerves innervating the mesenteric arteries to release the neurotransmitter AChE, which activates muscarinic or nicotinic receptors to modulate adrenergic neurotransmission. These results strongly suggest, that perivascular cholinergic nerves have little or no effect on the adrenergic nerve function in mesenteric arteries. The cholinergic nerves innervating mesenteric arteries do not mediate direct vascular responses.

  13. Integral experiments on in-vessel coolability and vessel creep: results and analysis of the FOREVER-C1 test

    Energy Technology Data Exchange (ETDEWEB)

    Sehgal, B.R.; Nourgaliev, R.R.; Dinh, T.N.; Karbojian, A. [Division of Nuclear Power Safety, Royal Institute of Technology, Drottning Kristinas Vaeg., Stockholm (Sweden)

    1999-07-01

    This paper describes the FOREVER (Failure Of REactor VEssel Retention) experimental program, which is currently underway at the Division of Nuclear Power Safety, Royal Institute of Technology (RIT/NPS). The objectives of the FOREVER experiments are to obtain data and develop validated models (i) on the melt coolability process inside the vessel, in the presence of water (in particular, on the efficacy of the postulated gap cooling to preclude vessel failure); and (ii) on the lower head failure due to the creep process in the absence of water inside and/or outside the lower head. The paper presents the experimental results and analysis of the first FOREVER-C1 test. During this experiment, the 1/10th scale pressure vessel, heated to about 900degC and pressurized to 26 bars, was subjected to creep deformation in a non-stop 24-hours test. The vessel wall displacement data clearly shows different stages of the vessel deformation due to thermal expansion, elastic, plastic and creep processes. The maximum displacement was observed at the lowermost region of the vessel lower plenum. Information on the FOREVER-C1 measured thermal characteristics and analysis of the observed thermal and structural behavior is presented. The coupled nature of thermal and mechanical processes, as well as the effect of other system conditions (such as depressurization) on the melt pool and vessel temperature responses are analyzed. (author)

  14. Research vessels

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, P.S.

    by the research vessels RV Gaveshani and ORV Sagar Kanya are reported. The work carried out by the three charted ships is also recorded. A short note on cruise plans for the study of ferromanganese nodules is added...

  15. [The application of ultrasonography to estimate blood vessel injury of upper limbs sustaining electric burns].

    Science.gov (United States)

    Chai, Jia-ke; Li, Li-gen; Chen, Yue-xiu; Hu, Xiao-juan; Yang, Yong-ming

    2003-12-01

    To explore a new method in estimating extent and degree of arterial injury in upper limbs sustaining high tension electric burns. Eighteen patients (twenty-four upper limbs) with high tension electricity injury were admitted from December 1998 to September 2002, The damaged limbs consisted of four parts: wrist wound part, 5 cm, 10 cm, 15 cm parts around wrist wound, where the radial and ulnar arteries were detected using B ultrasound and color WP Doppler examination. The changes of endangium, vessel diameter, thickness of the vessel wall and volume of blood flow were recorded respectively. The parameters of normal radial and ulnar arteries were also determined as normal control. B ultrasound and color WP Doppler examination showed that the endangium in radial and ulnar arteries become coarse, edema or exfoliation. The vessel wall was thicker than that of the normal control and the thickness was heterogeneity. The vessel wall could be necrosis in severe patient and the vessel cavity was stricture or beaded. Thrombosis or occlusion could occur at the site of severe injury area in vessel. The decrease in volume of blood flow was observed. The condition of the radial and ulnar arteries become well apart from 10 - 15 cm of wrist wound. The ultrasonography can be used to detect the changes in endangium, diameter, thickness of the vessel wall, blood flow volume in injury blood vessel caused by electric burn injury. It is helpful in judging the degree and extent of injury vessel and could be a safe, non-invasive diagnostic method and is worth popularizing.

  16. Benefits and drawbacks of TOFD and SAFT for crack depth measurement at thick-walled vessels; Vor- und Nachteile von TOFD und SAFT zur Risstiefenmessung an dickwandigen Behaeltern

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, V.; Mueller, W. [IZFP, Saarbruecken (Germany); Hecht, A. [BASF AG, Ludwigshafen (Germany)

    1999-08-01

    The results presented in the paper show that TOFD can be applied in many cases as a low-cost and reliable testing method, but is less suitable for some cases. These are: Description of cracks in welded joints which yield a multitude of data, as e.g. microstructural data, so that the method is less suitable for austenitic weld testing; detection of small cracks. (orig./CB) [Deutsch] Aus den gezeigten Beispielen ergibt sich, dass TOFD in einer Vielzahl von Anwendungsfaellen als preisguenstiges und zuverlaessiges Pruefverfahren eingesetzt werden kann, dass es aber fuer einige Anwendungsfaelle weniger geeignet ist: Diese Anwendungsfaelle sind: (1) Nachweis von Rissen in Schweissnaehten mit vielen Anzeigen, z.B. Gefuegeanzeigen, d.h. insbesondere bei austenitischen Schweissnaehten, und (2) Nachweis von kleinen Rissen. Der Nachweis auch von kleinen Rissen wird dahingegen beim Impuls-Echo Verfahren aufgrund des vorliegenden Winkelspiegeleffektes durchaus moeglich sein. Durch eine nachgeschaltete SAFT-Auswertung werden zum einen stoerendes Gefuegerauschen unterdrueckt und zum anderen Echos von Fehlstellen angehoben. Diese Verbesserung des Signal-Rausch-Abstandes fuehrt zu einer Verbesserung der Fehlererkennbarkeit und der Fehlerbewertung. (orig.)

  17. Vessel wall reactions to endovascular stent implantation

    NARCIS (Netherlands)

    H.M.M. van Beusekom (Heleen)

    1993-01-01

    textabstractIn order to gain insight in the effects of stenting, we studied the process of wound healing and the short- and long-term effect of these permanently present foreign bodies. Both thrombogenic and less thrombogenic metals were evaluated with respect to thrombogenicity and tissue response.

  18. Thinner regions of intracranial aneurysm wall correlate with regions of higher wall shear stress: a 7.0 tesla MRI

    Science.gov (United States)

    Blankena, Roos; Kleinloog, Rachel; Verweij, Bon H.; van Ooij, Pim; ten Haken, Bennie; Luijten, Peter R.; Rinkel, Gabriel J.E.; Zwanenburg, Jaco J.M.

    2016-01-01

    Purpose To develop a method for semi-quantitative wall thickness assessment on in vivo 7.0 tesla (7T) MRI images of intracranial aneurysms for studying the relation between apparent aneurysm wall thickness and wall shear stress. Materials and Methods Wall thickness was analyzed in 11 unruptured aneurysms in 9 patients, who underwent 7T MRI with a TSE based vessel wall sequence (0.8 mm isotropic resolution). A custom analysis program determined the in vivo aneurysm wall intensities, which were normalized to signal of nearby brain tissue and were used as measure for apparent wall thickness (AWT). Spatial wall thickness variation was determined as the interquartile range in AWT (the middle 50% of the AWT range). Wall shear stress was determined using phase contrast MRI (0.5 mm isotropic resolution). We performed visual and statistical comparisons (Pearson’s correlation) to study the relation between wall thickness and wall shear stress. Results 3D colored AWT maps of the aneurysms showed spatial AWT variation, which ranged from 0.07 to 0.53, with a mean variation of 0.22 (a variation of 1.0 roughly means a wall thickness variation of one voxel (0.8mm)). In all aneurysms, AWT was inversely related to WSS (mean correlation coefficient −0.35, P<0.05). Conclusions A method was developed to measure the wall thickness semi-quantitatively, using 7T MRI. An inverse correlation between wall shear stress and AWT was determined. In future studies, this non-invasive method can be used to assess spatial wall thickness variation in relation to pathophysiologic processes such as aneurysm growth and –rupture. PMID:26892986

  19. Shock-induced collapse of a bubble inside a deformable vessel

    Science.gov (United States)

    Coralic, Vedran; Colonius, Tim

    2013-01-01

    Shockwave lithotripsy repeatedly focuses shockwaves on kidney stones to induce their fracture, partially through cavitation erosion. A typical side effect of the procedure is hemorrhage, which is potentially the result of the growth and collapse of bubbles inside blood vessels. To identify the mechanisms by which shock-induced collapse could lead to the onset of injury, we study an idealized problem involving a preexisting bubble in a deformable vessel. We utilize a high-order accurate, shock- and interface-capturing, finite-volume scheme and simulate the three-dimensional shock-induced collapse of an air bubble immersed in a cylindrical water column which is embedded in a gelatin/water mixture. The mixture is a soft tissue simulant, 10% gelatin by weight, and is modeled by the stiffened gas equation of state. The bubble dynamics of this model configuration are characterized by the collapse of the bubble and its subsequent jetting in the direction of the propagation of the shockwave. The vessel wall, which is defined by the material interface between the water and gelatin/water mixture, is invaginated by the collapse and distended by the impact of the jet. The present results show that the highest measured pressures and deformations occur when the volumetric confinement of the bubble is strongest, the bubble is nearest the vessel wall and/or the angle of incidence of the shockwave reduces the distance between the jet tip and the nearest vessel surface. For a particular case considered, the 40 MPa shockwave utilized in this study to collapse the bubble generated a vessel wall pressure of almost 450 MPa and produced both an invagination and distention of nearly 50% of the initial vessel radius on a 𝒪(10) ns timescale. These results are indicative of the significant potential of shock-induced collapse to contribute to the injury of blood vessels in shockwave lithotripsy. PMID:24015027

  20. Network of endocardial vessels.

    Science.gov (United States)

    Lee, Byung-Cheon; Kim, Hong Bae; Sung, Baeckkyoung; Kim, Ki Woo; Sohn, Jamin; Son, Boram; Chang, Byung-Joon; Soh, Kwang-Sup

    2011-01-01

    Although there have been reports on threadlike structures inside the heart, they have received little attention. We aimed to develop a method for observing such structures and to reveal their ultrastructures. An in situ staining method, which uses a series of procedures of 0.2-0.4% trypan blue spraying and washing, was applied to observe threadlike structures on the surfaces of endocardia. The threadlike structures were isolated and observed by using confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). Networks of endocardial vessels (20 μm in thickness) with expansions (40-100 μm in diameter) were visualized; they were movable on the endocardium of the bovine atrium and ventricle. CLSM showed that (1) rod-shaped nuclei were aligned along the longitudinal direction of the endocardial vessel and (2) there were many cells inside the expansion. TEM on the endocardial vessel revealed that (1) there existed multiple lumens (1-7 μm in diameter) and (2) the extracellular matrices mostly consisted of collagen fibers, which were aligned along the longitudinal direction of the endocardial vessel or were locally organized in reticular structures. We investigated the endocardial circulatory system in bovine cardiac chambers and its ultrastructures, such as nucleic distributions, microlumens, and collagenous extracellular matrices. Copyright © 2011 S. Karger AG, Basel.

  1. Nuclear reactor construction with bottom supported reactor vessel

    Science.gov (United States)

    Sharbaugh, John E.

    1987-01-01

    An improved liquid metal nuclear reactor construction has a reactor core and a generally cylindrical reactor vessel for holding a large pool of low pressure liquid metal coolant and housing the core within the pool. The reactor vessel has an open top end, a closed flat bottom end wall and a continuous cylindrical closed side wall interconnecting the top end and bottom end wall. The reactor also has a generally cylindrical concrete containment structure surrounding the reactor vessel and being formed by a cylindrical side wall spaced outwardly from the reactor vessel side wall and a flat base mat spaced below the reactor vessel bottom end wall. A central support pedestal is anchored to the containment structure base mat and extends upwardly therefrom to the reactor vessel and upwardly therefrom to the reactor core so as to support the bottom end wall of the reactor vessel and the lower end of the reactor core in spaced apart relationship above the containment structure base mat. Also, an annular reinforced support structure is disposed in the reactor vessel on the bottom end wall thereof and extends about the lower end of the core so as to support the periphery thereof. In addition, an annular support ring having a plurality of inward radially extending linear members is disposed between the containment structure base mat and the bottom end of the reactor vessel wall and is connected to and supports the reactor vessel at its bottom end on the containment structure base mat so as to allow the reactor vessel to expand radially but substantially prevent any lateral motions that might be imposed by the occurrence of a seismic event. The reactor construction also includes a bed of insulating material in sand-like granular form, preferably being high density magnesium oxide particles, disposed between the containment structure base mat and the bottom end wall of the reactor vessel and uniformly supporting the reactor vessel at its bottom end wall on the containment

  2. Immunogold scanning electron microscopy can reveal the polysaccharide architecture of xylem cell walls.

    Science.gov (United States)

    Sun, Qiang; Sun, Yuliang; Juzenas, Kevin

    2017-04-01

    Immunofluorescence microscopy (IFM) and immunogold transmission electron microscopy (TEM) are the two main techniques commonly used to detect polysaccharides in plant cell walls. Both are important in localizing cell wall polysaccharides, but both have major limitations, such as low resolution in IFM and restricted sample size for immunogold TEM. In this study, we have developed a robust technique that combines immunocytochemistry with scanning electron microscopy (SEM) to study cell wall polysaccharide architecture in xylem cells at high resolution over large areas of sample. Using multiple cell wall monoclonal antibodies (mAbs), this immunogold SEM technique reliably localized groups of hemicellulosic and pectic polysaccharides in the cell walls of five different xylem structures (vessel elements, fibers, axial and ray parenchyma cells, and tyloses). This demonstrates its important advantages over the other two methods for studying cell wall polysaccharide composition and distribution in these structures. In addition, it can show the three-dimensional distribution of a polysaccharide group in the vessel lateral wall and the polysaccharide components in the cell wall of developing tyloses. This technique, therefore, should be valuable for understanding the cell wall polysaccharide composition, architecture and functions of diverse cell types. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  3. Vessel Operator System

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Operator cards are required for any operator of a charter/party boat and or a commercial vessel (including carrier and processor vessels) issued a vessel permit from...

  4. Heterogeneity and weak coupling may explain the synchronization characteristics of cells in the arterial wall

    DEFF Research Database (Denmark)

    Jacobsen, Jens Christian Brings; Aalkjær, Christian; Matchkov, Vladimir V

    2008-01-01

    development of force known as vasomotion. We present experimental data showing a considerable heterogeneity in cellular calcium dynamics in the vascular wall. In stimulated vessels, some SMCs remain quiescent, whereas others display waves of variable frequency. At the onset of vasomotion, all SMCs...... synchronization also requires a high-conductance pathway that provides strong coupling between the cells....

  5. Reactor vessel lower head integrity

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, A.M.

    1997-02-01

    On March 28, 1979, the Three Mile Island Unit 2 (TMI-2) nuclear power plant underwent a prolonged small break loss-of-coolant accident that resulted in severe damage to the reactor core. Post-accident examinations of the TMI-2 reactor core and lower plenum found that approximately 19,000 kg (19 metric tons) of molten material had relocated onto the lower head of the reactor vessel. Results of the OECD TMI-2 Vessel Investigation Project concluded that a localized hot spot of approximately 1 meter diameter had existed on the lower head. The maximum temperature on the inner surface of the reactor pressure vessel (RPV) in this region reached 1100{degrees}C and remained at that temperature for approximately 30 minutes before cooling occurred. Even under the combined loads of high temperature and high primary system pressure, the TMI-2 RPV did not fail. (i.e. The pressure varied from about 8.5 to 15 MPa during the four-hour period following the relocation of melt to the lower plenum.) Analyses of RPV failure under these conditions, using state-of-the-art computer codes, predicted that the RPV should have failed via local or global creep rupture. However, the vessel did not fail; and it has been hypothesized that rapid cooling of the debris and the vessel wall by water that was present in the lower plenum played an important role in maintaining RPV integrity during the accident. Although the exact mechanism(s) of how such cooling occurs is not known, it has been speculated that cooling in a small gap between the RPV wall and the crust, and/or in cracks within the debris itself, could result in sufficient cooling to maintain RPV integrity. Experimental data are needed to provide the basis to better understand these phenomena and improve models of RPV failure in severe accident codes.

  6. Nuclear reactor vessel fuel thermal insulating barrier

    Science.gov (United States)

    Keegan, C. Patrick; Scobel, James H.; Wright, Richard F.

    2013-03-19

    The reactor vessel of a nuclear reactor installation which is suspended from the cold leg nozzles in a reactor cavity is provided with a lower thermal insulating barrier spaced from the reactor vessel that has a hemispherical lower section that increases in volume from the center line of the reactor to the outer extent of the diameter of the thermal insulating barrier and smoothly transitions up the side walls of the vessel. The space between the thermal insulating harrier and the reactor vessel forms a chamber which can be flooded with cooling water through passive valving to directly cool the reactor vessel in the event of a severe accident. The passive inlet valve for the cooling water includes a buoyant door that is normally maintained sealed under its own weight and floats open when the cavity is Hooded. Passively opening steam vents are also provided.

  7. Safety assessment of in-vessel vapor explosion loads in next generation reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Kwang Hyun; Cho, Jong Rae; Choi, Byung Uk; Kim, Ki Yong; Lee, Kyung Jung [Korea Maritime University, Busan (Korea); Park, Ik Kyu [Seoul National University, Seoul (Korea)

    1998-12-01

    A safety assessment of the reactor vessel lower head integrity under in-vessel vapor explosion loads has been performed. The premixing and explosion calculations were performed using TRACER-II code. Using the calculated explosion pressures imposed on the lower head inner wall, strain calculations were performed using ANSYS code. The explosion analyses show that the explosion impulses are not altered significantly by the uncertain parameters of triggering location and time, fuel and vapor volume fractions in uniform premixture bounding calculations within the conservative ranges. Strain analyses using the calculated pressure loads on the lower head inner wall show that the vapor explosion-induced lower head failure is physically unreasonable. The static analysis using the conservative explosion-end pressure of 7,246 psia shows that the maximum equivalent strain is 4.3% at the bottom of lower head, which is less than the allowable threshold value of 11%. (author). 24 refs., 40 figs., 3 tabs.

  8. Effect of variable heat transfer coefficient on tissue temperature next to a large vessel during radiofrequency tumor ablation

    Directory of Open Access Journals (Sweden)

    Pinheiro Cleber

    2008-07-01

    Full Text Available Abstract Background One of the current shortcomings of radiofrequency (RF tumor ablation is its limited performance in regions close to large blood vessels, resulting in high recurrence rates at these locations. Computer models have been used to determine tissue temperatures during tumor ablation procedures. To simulate large vessels, either constant wall temperature or constant convective heat transfer coefficient (h have been assumed at the vessel surface to simulate convection. However, the actual distribution of the temperature on the vessel wall is non-uniform and time-varying, and this feature makes the convective coefficient variable. Methods This paper presents a realistic time-varying model in which h is a function of the temperature distribution at the vessel wall. The finite-element method (FEM was employed in order to model RF hepatic ablation. Two geometrical configurations were investigated. The RF electrode was placed at distances of 1 and 5 mm from a large vessel (10 mm diameter. Results When the ablation procedure takes longer than 1–2 min, the attained coagulation zone obtained with both time-varying h and constant h does not differ significantly. However, for short duration ablation (5–10 s and when the electrode is 1 mm away from the vessel, the use of constant h can lead to errors as high as 20% in the estimation of the coagulation zone. Conclusion For tumor ablation procedures typically lasting at least 5 min, this study shows that modeling the heat sink effect of large vessels by applying constant h as a boundary condition will yield precise results while reducing computational complexity. However, for other thermal therapies with shorter treatment using a time-varying h may be necessary.

  9. Smooth muscle–endothelial cell communication activates Reelin signaling and regulates lymphatic vessel formation

    Science.gov (United States)

    Lutter, Sophie; Xie, Sherry; Tatin, Florence

    2012-01-01

    Active lymph transport relies on smooth muscle cell (SMC) contractions around collecting lymphatic vessels, yet regulation of lymphatic vessel wall assembly and lymphatic pumping are poorly understood. Here, we identify Reelin, an extracellular matrix glycoprotein previously implicated in central nervous system development, as an important regulator of lymphatic vascular development. Reelin-deficient mice showed abnormal collecting lymphatic vessels, characterized by a reduced number of SMCs, abnormal expression of lymphatic capillary marker lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), and impaired function. Furthermore, we show that SMC recruitment to lymphatic vessels stimulated release and proteolytic processing of endothelium-derived Reelin. Lymphatic endothelial cells in turn responded to Reelin by up-regulating monocyte chemotactic protein 1 (MCP1) expression, which suggests an autocrine mechanism for Reelin-mediated control of endothelial factor expression upstream of SMC recruitment. These results uncover a mechanism by which Reelin signaling is activated by communication between the two cell types of the collecting lymphatic vessels—smooth muscle and endothelial cells—and highlight a hitherto unrecognized and important function for SMCs in lymphatic vessel morphogenesis and function. PMID:22665518

  10. Facial ulcerations due to Acinetobacter baumannii: Vessel thrombosis with bacterial mycelia

    Directory of Open Access Journals (Sweden)

    Dong Ming Li

    2014-01-01

    Full Text Available A 14-year-old girl presented with a 2-week history of progressive facial ulcerations that did not respond to cephalexin and topical dexamethasone. Biopsy on the ulcer showed rod-shaped bacteria and actinomycetes-like mycelia in the vessel walls and within thrombi. Tissue culture yielded Acinetobacter baumannii, which was resistant to cephalexin. A favourite outcome was achieved with minocycline treatment. This is the first case report of A. baumannii-related vasculitis.

  11. BIOASSAY VESSEL FAILURE ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Vormelker, P

    2008-09-22

    Two high-pressure bioassay vessels failed at the Savannah River Site during a microwave heating process for biosample testing. Improper installation of the thermal shield in the first failure caused the vessel to burst during microwave heating. The second vessel failure is attributed to overpressurization during a test run. Vessel failure appeared to initiate in the mold parting line, the thinnest cross-section of the octagonal vessel. No material flaws were found in the vessel that would impair its structural performance. Content weight should be minimized to reduce operating temperature and pressure. Outer vessel life is dependent on actual temperature exposure. Since thermal aging of the vessels can be detrimental to their performance, it was recommended that the vessels be used for a limited number of cycles to be determined by additional testing.

  12. Electroweak bubble wall speed limit

    Science.gov (United States)

    Bödeker, Dietrich; Moore, Guy D.

    2017-05-01

    In extensions of the Standard Model with extra scalars, the electroweak phase transition can be very strong, and the bubble walls can be highly relativistic. We revisit our previous argument that electroweak bubble walls can "run away," that is, achieve extreme ultrarelativistic velocities γ ~ 1014. We show that, when particles cross the bubble wall, they can emit transition radiation. Wall-frame soft processes, though suppressed by a power of the coupling α, have a significance enhanced by the γ-factor of the wall, limiting wall velocities to γ ~ 1/α. Though the bubble walls can move at almost the speed of light, they carry an infinitesimal share of the plasma's energy.

  13. Motional Effect on Wall Shear Stresses

    DEFF Research Database (Denmark)

    Kock, Samuel Alberg; Torben Fründ, Ernst; Yong Kim, Won

    Atherosclerosis is the leading cause of death and severe disability. Wall Shear Stress (WSS), the stress exerted on vessel walls by the flowing blood is a key factor in the development of atherosclerosis. Computational Fluid Dynamics (CFD) is widely used for WSS estimations. Most CFD simulations ...

  14. On-line monitoring and analysis of reactor vessel integrity

    Energy Technology Data Exchange (ETDEWEB)

    Ackerson, D.S.; Impink, A.J. Jr.; Balkey, K.R.; Andreychek, T.S.

    1989-01-31

    A method is described for on-line monitoring and analysis of nuclear reactor pressure vessel integrity in a unit in which reactor coolant is circulated along the inner wall of the pressure vessel, the method comprising the steps of: generating on an on-line basis, temperature signals representative of the temperature of the reactor coolant circulating along the inner wall of the pressure vessel; generating on an on-line basis, a pressure signal representative of the reactor coolant pressure; generating a signal representative of fast neutron fluence to which the reactor pressure vessel has been subjected; generating as a function of the fluence signal a visual representation of the actual real time reference nil-ductibility transition temperature (RT/sub ndt/) across the entire pressure vessel wall thickness at a preselected critical location in the wall; generating as a function of transients in the reactor coolant temperature and pressur signals, a visual representation of the real time required RT/sub ndt/, across the entire pressure vessel wall thickness at the selected critical location, the required RT/sub ndt/ being the RT/sub ndt/ that would be required in the pressure vessel wall for flaw initiation to occur as a result of stresses set-up by the transients; and superimposing the visual representations of the real-time actual and required RT/sub ndt's/ for flaw initiation across the entire pressure vessel wall thickness for the selected critical location to generate a visual representation of the difference in value between the actual and required RT/sub ndt/ presented as an RT/sub ndt/ margin.

  15. Leukoaraiosis is associated with arterial wall thickness: a quantitative analysis.

    Science.gov (United States)

    Auriel, Eitan; Csiba, Laszlo; Berenyi, Ervin; Varkonyi, Ildiko; Mehes, Gabor; Kardos, Laszlo; Karni, Arnon; Bornstein, Natan M

    2012-06-01

    Leukoaraiosis refers to an age-related, abnormal appearance of the brain white matter on neuroimaging. The association between leukoaraiosis and cerebrovascular disease suggests that ischemia may be an important contributing factor; however, the pathogenesis of the condition remains controversial. We hypothesized that physical abnormalities of blood vessels might be culpable and compared the external and internal measurements of blood vessel walls between brains that demonstrated leukoaraiosis on imaging and normal control brains. Fourteen brains of individuals who had been diagnosed as having severe leukoaraiosis and five non-leukoaraiosis control brains were studied. Arterial cross-sections were evaluated by length measurements with an image analysis device. Arterial wall thickness and the ratio of the outer and inner diameters of the vessel were measured. We measured a total of 108 vessels in the leukoaraiosis group and 95 vessels in the control group. The vessel walls of the leukoaraiosis patients were an average of 5.5 µm thicker than the walls of control vessels of the same inside diameter (P = 0.0000, 95% CI 3.01-8.08) and an average of 2.3 µm thicker than walls of control vessels of the same outside diameter (P = 0.016, 95% CI 0.48-4.17). Our data provide evidence that leukoaraiosis is associated with vessel wall thickening in an additive fashion and indicate that structural vascular abnormalities are associated with leukoaraiosis. © 2011 Japanese Society of Neuropathology.

  16. Hydrogen storage in insulated pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S.M.; Garcia-Villazana, O. [Lawrence Livermore National Lab., CA (United States)

    1998-08-01

    Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH{sub 2}) or ambient-temperature compressed hydrogen (CH{sub 2}). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (lower energy requirement for hydrogen liquefaction and reduced evaporative losses). This paper shows an evaluation of the applicability of the insulated pressure vessels for light-duty vehicles. The paper shows an evaluation of evaporative losses and insulation requirements and a description of the current analysis and experimental plans for testing insulated pressure vessels. The results show significant advantages to the use of insulated pressure vessels for light-duty vehicles.

  17. Guam Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Guam. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  18. Florida Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Florida. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  19. Vessel Arrival Info - Legacy

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Vessel Arrival Info is a spreadsheet that gets filled out during the initial stage of the debriefing process by the debriefer. It contains vessel name, trip...

  20. Mechanisms of VIP-induced inhibition of the lymphatic vessel pump.

    Science.gov (United States)

    von der Weid, Pierre-Yves; Rehal, Sonia; Dyrda, Peter; Lee, Stewart; Mathias, Ryan; Rahman, Mozibur; Roizes, Simon; Imtiaz, Mohammad S

    2012-06-01

    Lymphatic vessels serve as a route by which interstitial fluid, protein and other macromolecules are returned to the blood circulation and immune cells and antigens gain access to lymph nodes. Lymph flow is an active process promoted by rhythmical contraction-relaxation events occurring in the collecting lymphatic vessels. This lymphatic pumping is an intrinsic property of the lymphatic muscles in the vessel wall and consequent to action potentials. Compromised lymphatic pumping may affect lymph and immune cell transport, an action which could be particularly detrimental during inflammation. Importantly, many inflammatory mediators alter lymphatic pumping. Vasoactive intestinal peptide (VIP) is a neuro- and immuno-modulator thought to be released by nerve terminals and immune cells in close proximity to lymphatic vessels. We demonstrated the presence of the peptide in lymphatic vessels and in the lymph and examined the effects of VIP on mesenteric collecting lymphatic vessels of the guinea pig using pharmacological bioassays, intracellular microelectrode electrophysiology, immunofluorescence and quantitative real-time PCR. We showed that VIP alters lymphatic pumping by decreasing the frequency of lymphatic contractions and hyperpolarizing the lymphatic muscle membrane potential in a concentration-dependent manner. Our data further suggest that these effects are mainly mediated by stimulation of the VIP receptor VPAC2 located on the lymphatic muscle and the downstream involvement of protein kinase A (PKA) and ATP-sensitive K⁺ (KATP) channels. Inhibition of lymphatic pumping by VIP may compromise lymph drainage, oedema resolution and immune cell trafficking to the draining lymph nodes.

  1. Supersymmetric domain walls

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Kleinschmidt, Axel; Riccioni, Fabio

    2012-01-01

    We classify the half-supersymmetric "domain walls," i.e., branes of codimension one, in toroidally compactified IIA/IIB string theory and show to which gauged supergravity theory each of these domain walls belong. We use as input the requirement of supersymmetric Wess-Zumino terms, the properties of

  2. ALICE HMPID Radiator Vessel

    CERN Multimedia

    2003-01-01

    View of the radiator vessels of the ALICE/HMPID mounted on the support frame. Each HMPID module is equipped with 3 indipendent radiator vessels made out of neoceram and fused silica (quartz) windows glued together. The spacers inside the vessel are needed to stand the hydrostatic pressure. http://alice-hmpid.web.cern.ch/alice-hmpid

  3. Aseismic safety analysis of a prestressed concrete containment vessel for CPR1000 nuclear power plant

    Science.gov (United States)

    Yi, Ping; Wang, Qingkang; Kong, Xianjing

    2017-01-01

    The containment vessel of a nuclear power plant is the last barrier to prevent nuclear reactor radiation. Aseismic safety analysis is the key to appropriate containment vessel design. A prestressed concrete containment vessel (PCCV) model with a semi-infinite elastic foundation and practical arrangement of tendons has been established to analyze the aseismic ability of the CPR1000 PCCV structure under seismic loads and internal pressure. A method to model the prestressing tendon and its interaction with concrete was proposed and the axial force of the prestressing tendons showed that the simulation was reasonable and accurate. The numerical results show that for the concrete structure, the location of the cylinder wall bottom around the equipment hatch and near the ring beam are critical locations with large principal stress. The concrete cracks occurred at the bottom of the PCCV cylinder wall under the peak earthquake motion of 0.50 g, however the PCCV was still basically in an elastic state. Furthermore, the concrete cracks occurred around the equipment hatch under the design internal pressure of 0.4MPa, but the steel liner was still in the elastic stage and its leak-proof function soundness was verified. The results provide the basis for analysis and design of containment vessels.

  4. [Bladder injury by penetration of artificial vessel graft].

    Science.gov (United States)

    Wada, Naoki; Tamaki, Gaku; Kura, Tatsuhiko; Saga, Yuji; Kakizaki, Hidehiro

    2009-01-01

    Iatrogenic bladder injury by artificial vessel graft is extremely rare and only 3 cases have been reported. Herein, we report a case of bladder injury by penetration of artificial vessel graft. An 80-year-old male underwent a femoro-femoral crossover bypass surgery for arteriosclerosis obliterans in our hospital. Postoperatively he complained of urinary incontinence and was referred to the urology department. Ultrasonography for evaluating microscopic hematuria revealed a high echoic linear structure in the bladder and subsequent cystoscopy found an artificial vessel graft penetrating bladder wall. Vascular surgeons reconstructed femoro-femoral bypass and we removed the artificial vessel graft and repaired the injured bladder wall. This is the fourth case of bladder penetrating injury by artificial vessel graft and we summarize the reported cases.

  5. Exponential Stabilization of an Underactuated Surface Vessel

    Directory of Open Access Journals (Sweden)

    Kristin Y. Pettersen

    1997-07-01

    Full Text Available The paper shows that a large class of underactuated vehicles cannot be asymptotically stabilized by either continuous or discontinuous state feedback. Furthermore, stabilization of an underactuated surface vessel is considered. Controllability properties of the surface vessels is presented, and a continuous periodic time-varying feedback law is proposed. It is shown that this feedback law exponentially stabilizes the surface vessel to the origin, and this is illustrated by simulations.

  6. Behavior of platelets stained by 5,6-CF-encapsulated PEGylated liposomes after laser irradiation of vessel wall: an in-vivo model for studying site-selective delivery of diagnostic or therapeutic agents

    Science.gov (United States)

    Mordon, Serge R.; Begu, Sylvie; Buys, Bruno; Tourne-Peteilh, Corine; Devoisselle, Jean-Marie

    2001-05-01

    Vascular endothelium serves as an extensive interface between circulating blood and various tissues and organs of the body. As such, it offers an accessible target for blood-borne pharmacological and genetic manipulations that can mediate both local and systemic effects. Thus, targeting of liposomes to activated vascular endothelial cells may provide a strategy for site-selective delivery in the vascular system with broad therapeutic applicability. This study aimed to evaluate an intravital fluorescence imaging technique to visualize in-situ and in real-time the activation of platelets after staining by 5,6-CF- encapsulated PEGylated liposomes injected intravenously. The study was performed on skin by using a dorsal skin-fold chamber implanted in golden hamsters using intravital microscopy. The skin micro circulation was observed with an intravital microscope (using x25 and x40 magnification) fitted with a Xenon light source and an epi-fluorescence assembly. An ultra-high sensitivity video-camera mounted on the microscope projected the image onto a monitor, and the images were recorded for play-back analysis with a digital video cassette recorder. An inflammatory response was induced by an Argon laser emitting at 514.5nm. The 80micrometers laser beam was focused on a vessel and its position was controlled with the microscope imaging system, it was possible to see individual platelets flowing in blood vessels. As liposomes were labeled with a fluorescent probe which was hydrophilic (located in the aqueous phase), the fluorescence of platelets was due only to the uptake of liposomes. After laser irradiation, platelets activation at sites of vascular injury was obtained. Tethering, translocation of some platelets inside the irradiated zone were clearly seen. At last, detachment and extravasation of platelets were observed. A perivascular fluorescence confirmed that platelets migrated across the basal lamina into the dermal connective tissue. In conclusion, staining of

  7. Page 1 Multiferforate Plates in Xylem Vessels of Monocotyledonous ...

    Indian Academy of Sciences (India)

    Transverse section of a root of Alocasia indica showing 6 multiperforate plates in the vessel segments of the metaxylem. X46. FIG. 2.-A number of vessel segments from the root of Crinum asiaticum showing the two ends, x 15. FIG. 3.-Figure showing the arrangement of adjacent vessel segments with long oblique ends.

  8. Grounding Damage to Conventional Vessels

    DEFF Research Database (Denmark)

    Lützen, Marie; Simonsen, Bo Cerup

    2003-01-01

    regulations for design of bottom compartment layout with regard to grounding damages are largely based on statistical damage data. New and updated damage statistics holding 930 grounding accident records has been investigated. The bottom damage statistics is compared to current regulations for the bottom......The present paper is concerned with rational design of conventional vessels with regard to bottom damage generated in grounding accidents. The aim of the work described here is to improve the design basis, primarily through analysis of new statistical data for grounding damage. The current...... for the relation between the amount of deformed structure and the energy absorption. Finally, the paper shows how damage statistics for existing, conventional vessels can be used together with theoretical prediction methods for determining grounding damage distributions for new vessel types not included...

  9. Domain walls on the brane

    NARCIS (Netherlands)

    Bergshoeff, E; van der Schaar, JP; Papadopoulos, G

    1998-01-01

    We show that all branes admit worldvolume domain wall solutions. We find one class of solutions for which the tension of the brane changes discontinuously along the domain wall. These solutions are not supersymmetric. We argue that there is another class of domain wall solutions which is

  10. Pressure vessel design manual

    CERN Document Server

    Moss, Dennis R

    2013-01-01

    Pressure vessels are closed containers designed to hold gases or liquids at a pressure substantially different from the ambient pressure. They have a variety of applications in industry, including in oil refineries, nuclear reactors, vehicle airbrake reservoirs, and more. The pressure differential with such vessels is dangerous, and due to the risk of accident and fatality around their use, the design, manufacture, operation and inspection of pressure vessels is regulated by engineering authorities and guided by legal codes and standards. Pressure Vessel Design Manual is a solutions-focused guide to the many problems and technical challenges involved in the design of pressure vessels to match stringent standards and codes. It brings together otherwise scattered information and explanations into one easy-to-use resource to minimize research and take readers from problem to solution in the most direct manner possible. * Covers almost all problems that a working pressure vessel designer can expect to face, with ...

  11. Ambiguous walls

    DEFF Research Database (Denmark)

    Mody, Astrid

    2012-01-01

    of “ambiguous walls” as a more “critical” approach to design [1]. The concept of ambiguous walls refers to the diffuse status a lumious and possibly responsive wall will have. Instead of confining it can open up. Instead of having a static appearance, it becomes a context over time. Instead of being hard...... and flat, “ambiguous walls” combine softness, tectonics and three-dimensionality. The paper considers a selection of luminious surfaces and reflects on the extent of their ambiguous qualities. Initial ideas for new directions for the wall will be essayed through the discussion....

  12. Maury Journals - German Vessels

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — German vessels observations, after the 1853 Brussels Conference that set International Maritime Standards, modeled after Maury Marine Standard Observations.

  13. Streaming flow from ultrasound contrast agents by acoustic waves in a blood vessel model.

    Science.gov (United States)

    Cho, Eunjin; Chung, Sang Kug; Rhee, Kyehan

    2015-09-01

    To elucidate the effects of streaming flow on ultrasound contrast agent (UCA)-assisted drug delivery, streaming velocity fields from sonicated UCA microbubbles were measured using particle image velocimetry (PIV) in a blood vessel model. At the beginning of ultrasound sonication, the UCA bubbles formed clusters and translated in the direction of the ultrasound field. Bubble cluster formation and translation were faster with 2.25MHz sonication, a frequency close to the resonance frequency of the UCA. Translation of bubble clusters induced streaming jet flow that impinged on the vessel wall, forming symmetric vortices. The maximum streaming velocity was about 60mm/s at 2.25MHz and decreased to 15mm/s at 1.0MHz for the same acoustic pressure amplitude. The effect of the ultrasound frequency on wall shear stress was more noticeable. Maximum wall shear stress decreased from 0.84 to 0.1Pa as the ultrasound frequency decreased from 2.25 to 1.0MHz. The maximum spatial gradient of the wall shear stress also decreased from 1.0 to 0.1Pa/mm. This study showed that streaming flow was induced by bubble cluster formation and translation and was stronger upon sonication by an acoustic wave with a frequency near the UCA resonance frequency. Therefore, the secondary radiant force, which is much stronger at the resonance frequency, should play an important role in UCA-assisted drug delivery. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Thermal energy storage using Prestressed Cast Iron Vessels (PCIV). Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gilli, P.V.; Beckmann, G.; Schilling, F.E.

    1977-06-01

    The wide-spread application of thermal energy and high-pressure air storage to electric power generation has so far been hampered by the lack of large high-pressure storage vessels of reasonable cost. Welded steel vessels are too expensive for this purpose. However, the Prestressed Cast Iron Vessel (PCIV), developed as a nuclear reactor pressure vessel by Siempelkamp Giesserei KG of Krefeld, FRG, has the potential of complying with these requirements. Applications of the PCIV include: high-pressure air storage for the quick start-up of open cycle gas turbines; pressurized high-temperature sensible heat storage by means of solids with a gaseous heat transfer medium for closed cycle gas turbines of future solar power stations; and pressurized hot water storage for nuclear, solar, or coal-fired steam power plants, employing either separate peaking turbines or overloadable main turbine sets. A reference PCIV of 8000 m/sup 3/, 275/sup 0/C, with hot going walls and cold going tendons was developed, designed, and stress-analysed. A parametric study showed that pressures between 4 and 8 MPa and L/D ratios larger than 4 should be optimal. Cost of the reference vessel is about $10,000,000 or 33 to 50 $/kWh electric energy stored. Cost of peak power will be from 30 to 100 mills/kWh, depending on many parameters.

  15. PRESSURE-RESISTANT VESSEL

    NARCIS (Netherlands)

    Beukers, A.; De Jong, T.

    1997-01-01

    Abstract of WO 9717570 (A1) The invention is directed to a wheel-shaped pressure-resistant vessel for gaseous, liquid or liquefied material having a substantially rigid shape, said vessel comprising a substantially continuous shell of a fiber-reinforced resin having a central opening, an inner

  16. Regulator of calcineurin 1 mediates pathological vascular wall remodeling

    Science.gov (United States)

    Esteban, Vanesa; Méndez-Barbero, Nerea; Jesús Jiménez-Borreguero, Luis; Roqué, Mercè; Novensá, Laura; Belén García-Redondo, Ana; Salaices, Mercedes; Vila, Luis; Arbonés, María L.

    2011-01-01

    Artery wall remodeling, a major feature of diseases such as hypertension, restenosis, atherosclerosis, and aneurysm, involves changes in the tunica media mass that reduce or increase the vessel lumen. The identification of molecules involved in vessel remodeling could aid the development of improved treatments for these pathologies. Angiotensin II (AngII) is a key effector of aortic wall remodeling that contributes to aneurysm formation and restenosis through incompletely defined signaling pathways. We show that AngII induces vascular smooth muscle cell (VSMC) migration and vessel remodeling in mouse models of restenosis and aneurysm. These effects were prevented by pharmacological inhibition of calcineurin (CN) or lentiviral delivery of CN-inhibitory peptides. Whole-genome analysis revealed >1,500 AngII-regulated genes in VSMCs, with just 11 of them requiring CN activation. Of these, the most sensitive to CN activation was regulator of CN 1 (Rcan1). Rcan1 was strongly activated by AngII in vitro and in vivo and was required for AngII-induced VSMC migration. Remarkably, Rcan1−/− mice were resistant to AngII-induced aneurysm and restenosis. Our results indicate that aneurysm formation and restenosis share mechanistic elements and identify Rcan1 as a potential therapeutic target for prevention of aneurysm and restenosis progression. PMID:21930771

  17. Cell wall modifications in Arabidopsis plants with altered alpha-L-arabinofuranosidase activity.

    Science.gov (United States)

    Chávez Montes, Ricardo A; Ranocha, Philippe; Martinez, Yves; Minic, Zoran; Jouanin, Lise; Marquis, Mélanie; Saulnier, Luc; Fulton, Lynette M; Cobbett, Christopher S; Bitton, Frédérique; Renou, Jean-Pierre; Jauneau, Alain; Goffner, Deborah

    2008-05-01

    Although cell wall remodeling is an essential feature of plant growth and development, the underlying molecular mechanisms are poorly understood. This work describes the characterization of Arabidopsis (Arabidopsis thaliana) plants with altered expression of ARAF1, a bifunctional alpha-L-arabinofuranosidase/beta-D-xylosidase (At3g10740) belonging to family 51 glycosyl-hydrolases. ARAF1 was localized in several cell types in the vascular system of roots and stems, including xylem vessels and parenchyma cells surrounding the vessels, the cambium, and the phloem. araf1 T-DNA insertional mutants showed no visible phenotype, whereas transgenic plants that overexpressed ARAF1 exhibited a delay in inflorescence emergence and altered stem architecture. Although global monosaccharide analysis indicated only slight differences in cell wall composition in both mutant and overexpressing lines, immunolocalization experiments using anti-arabinan (LM6) and anti-xylan (LM10) antibodies indicated cell type-specific alterations in cell wall structure. In araf1 mutants, an increase in LM6 signal intensity was observed in the phloem, cambium, and xylem parenchyma in stems and roots, largely coinciding with ARAF1 expression sites. The ectopic overexpression of ARAF1 resulted in an increase in LM10 labeling in the secondary walls of interfascicular fibers and xylem vessels. The combined ARAF1 gene expression and immunolocalization studies suggest that arabinan-containing pectins are potential in vivo substrates of ARAF1 in Arabidopsis.

  18. Cell Wall Modifications in Arabidopsis Plants with Altered α-l-Arabinofuranosidase Activity[C][W

    Science.gov (United States)

    Chávez Montes, Ricardo A.; Ranocha, Philippe; Martinez, Yves; Minic, Zoran; Jouanin, Lise; Marquis, Mélanie; Saulnier, Luc; Fulton, Lynette M.; Cobbett, Christopher S.; Bitton, Frédérique; Renou, Jean-Pierre; Jauneau, Alain; Goffner, Deborah

    2008-01-01

    Although cell wall remodeling is an essential feature of plant growth and development, the underlying molecular mechanisms are poorly understood. This work describes the characterization of Arabidopsis (Arabidopsis thaliana) plants with altered expression of ARAF1, a bifunctional α-l-arabinofuranosidase/β-d-xylosidase (At3g10740) belonging to family 51 glycosyl-hydrolases. ARAF1 was localized in several cell types in the vascular system of roots and stems, including xylem vessels and parenchyma cells surrounding the vessels, the cambium, and the phloem. araf1 T-DNA insertional mutants showed no visible phenotype, whereas transgenic plants that overexpressed ARAF1 exhibited a delay in inflorescence emergence and altered stem architecture. Although global monosaccharide analysis indicated only slight differences in cell wall composition in both mutant and overexpressing lines, immunolocalization experiments using anti-arabinan (LM6) and anti-xylan (LM10) antibodies indicated cell type-specific alterations in cell wall structure. In araf1 mutants, an increase in LM6 signal intensity was observed in the phloem, cambium, and xylem parenchyma in stems and roots, largely coinciding with ARAF1 expression sites. The ectopic overexpression of ARAF1 resulted in an increase in LM10 labeling in the secondary walls of interfascicular fibers and xylem vessels. The combined ARAF1 gene expression and immunolocalization studies suggest that arabinan-containing pectins are potential in vivo substrates of ARAF1 in Arabidopsis. PMID:18344421

  19. Containment vessel drain system

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Scott G.

    2018-01-30

    A system for draining a containment vessel may include a drain inlet located in a lower portion of the containment vessel. The containment vessel may be at least partially filled with a liquid, and the drain inlet may be located below a surface of the liquid. The system may further comprise an inlet located in an upper portion of the containment vessel. The inlet may be configured to insert pressurized gas into the containment vessel to form a pressurized region above the surface of the liquid, and the pressurized region may operate to apply a surface pressure that forces the liquid into the drain inlet. Additionally, a fluid separation device may be operatively connected to the drain inlet. The fluid separation device may be configured to separate the liquid from the pressurized gas that enters the drain inlet after the surface of the liquid falls below the drain inlet.

  20. Application of DTM for 2D viscous flow through expanding or contracting gaps with permeable walls

    Directory of Open Access Journals (Sweden)

    E. Mohammadian

    2014-12-01

    Full Text Available In this study, Differential Transformation Method is used to solve the problem of laminar, isothermal, incompressible and viscous flow in a rectangular domain bounded by two moving porous walls, which enable the fluid to enter or exit during successive expansions or contractions. The concept of this method is briefly introduced, and it’s application for this problem is studied. Then, the results are compared with numerical results and the validity of these methods is shown. After this verification, we analyze the effects of some physical applicable parameters to show the efficiency of DTM for this type of problems. Graphical results are presented to investigate the influence of the non-dimensional wall dilation rate ( and permeation Reynolds number ( on the velocity, normal pressure distribution and wall shear stress. The present problem for slowly expanding or contracting walls with weak permeability is a simple model for the transport of biological fluids through contracting or expanding vessels.

  1. Effect of Recombinant Human Epidermal Growth Factor Impregnated Chitosan Film on Hemostasis and Healing of Blood Vessels

    Directory of Open Access Journals (Sweden)

    Sangshin Lee

    2014-09-01

    Full Text Available BackgroundBleeding can be a problem in wound debridement. In search for an effective hemostatic agent, we experimented with a chitosan film combined with the recombinant human epidermal growth factor (rh-EGF, hypothesizing that it would achieve effective hemostasis and simultaneously enhance arterial healing.MethodsForty-eight Sprague-Dawley rats were used, and 96 puncture wounds were made. The wounds were divided into the following four groups: treated with sterile gauze, treated with gelatin sponge, treated with chitosan, and treated with chitosan combined with rh-EGF. Immediate hemostasis was evaluated, and arterial healing was observed histologically.ResultsGroups B, C, and D showed a significant rate of immediate hemostasis as compared to group A (P<0.05, but there were no significant differences among groups B, C, and D. Histologically, only group D showed good continuity of the vessel wall after 1 week. It was the only group to show smooth muscle cell nuclei of the vessel wall.ConclusionsWe observed that chitosan has an effective hemostatic potential and the mix of rh-EGF and chitosan does not interfere with chitosan's hemostatic capabilities. We also identified enhanced healing of vessel walls when rh-EGF was added to chitosan. Further research based on these positive findings is needed to evaluate the potential use of this combination on difficult wounds like chronic diabetic ulcerations.

  2. Progress of ITER vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Ioki, K., E-mail: Kimihiro.Ioki@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Bayon, A. [F4E, c/ Josep Pla, No. 2, Torres Diagonal Litoral, Edificio B3, E-08019 Barcelona (Spain); Choi, C.H.; Daly, E.; Dani, S.; Davis, J.; Giraud, B.; Gribov, Y.; Hamlyn-Harris, C.; Jun, C.; Levesy, B. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Kim, B.C. [NFRI, 52 Yeoeundong Yuseonggu, Daejeon 305-333 (Korea, Republic of); Kuzmin, E. [NTC “Sintez”, Efremov Inst., 189631 Metallostroy, St. Petersburg (Russian Federation); Le Barbier, R.; Martinez, J.-M. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Pathak, H. [ITER-India, A-29, GIDC Electronic Estate, Sector 25, Gandhinagar 382025 (India); Preble, J. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Sa, J.W. [NFRI, 52 Yeoeundong Yuseonggu, Daejeon 305-333 (Korea, Republic of); Terasawa, A.; Utin, Yu. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); and others

    2013-10-15

    Highlights: ► This covers the overall status and progress of the ITER vacuum vessel activities. ► It includes design, R and D, manufacturing and approval process of the regulators. ► The baseline design was completed and now manufacturing designs are on-going. ► R and D includes ISI, dynamic test of keys and lip-seal welding/cutting technology. ► The VV suppliers produced full-scale mock-ups and started VV manufacturing. -- Abstract: Design modifications were implemented in the vacuum vessel (VV) baseline design in 2011–2012 for finalization. The modifications are mostly due to interface components, such as support rails and feedthroughs for the in-vessel coils (IVC). Manufacturing designs are being developed at the domestic agencies (DAs) based on the baseline design. The VV support design was also finalized and tests on scale mock-ups are under preparation. Design of the in-wall shielding (IWS) has progressed, considering the assembly methods and the required tolerances. Further modifications are required to be consistent with the DAs’ manufacturing designs. Dynamic tests on the inter-modular and stub keys to support the blanket modules are being performed to measure the dynamic amplification factor (DAF). An in-service inspection (ISI) plan has been developed and R and D was launched for ISI. Conceptual design of the VV instrumentation has been developed. The VV baseline design was approved by the agreed notified body (ANB) in accordance with the French Nuclear Pressure Equipment Order procedure.

  3. Radical resection of giant chondrosarcoma of the anterior chest wall

    Directory of Open Access Journals (Sweden)

    Stanić Vojkan

    2008-01-01

    Full Text Available Background. Chondrosarcomas represent approximately 30% of primary malignant bone tumors, the most frequent of which is on anterior thoracic wall. Case report. We presented a case of 50-year-old man suffering from a slowgrowing, painless giant chondrosarcoma of the anterior chest wall. A wide resection was performed to excise the tumor including attached skin, right breast, ribs, sternum, soft tissues and parietal pleura. Mediastinum was not affected by the tumor. After resecting a 26 × 20 × 22 cm segment, the chest wall defect was reconstructed with a Marlex mesh and extensive latissimus dorsi myocutaneous flap pedicled on the right thoracodorsal vessels. Histopatology diagnosis was chondrosarcoma G 2−3. The mechanics of ventilation was not altered and respiratory function was normal from the immediate postoperative period. Three years after the operation postoperative results showed no local recurrence and excellent functional and aesthetic results were evident. Respiratory function remained unaltered. Conclusion. According to the results it can be concluded that the use of Marlex mash and myocutaneous flap is good method for stabilization of the chest wall and enough to avoid paradoxical respiratory movements in managing giant chondrosarcoma of the anterior chest wall.

  4. Disruption-induced poloidal currents in the tokamak wall

    Energy Technology Data Exchange (ETDEWEB)

    Pustovitov, V.D., E-mail: Pustovitov_VD@nrcki.ru [National Research Centre ‘Kurchatov Institute’, Pl. Kurchatova 1, Moscow 123182 (Russian Federation); National Research Nuclear University MEPhI, Kashirskoe sh. 31, Moscow 115409, Russia (Russian Federation)

    2017-04-15

    Highlights: • Induction effects during disruptions and rapid transient events in tokamaks. • Plasma-wall electromagnetic interaction. • Flux-conserving evolution of plasma equilibrium. • Poloidal current induced in the vacuum vessel wall in a tokamak. • Complete analytical derivations and estimates. - Abstract: The poloidal current induced in the tokamak wall during fast transient events is analytically evaluated. The analysis is based on the electromagnetic relations coupled with plasma equilibrium equations. The derived formulas describe the consequences of both thermal and current quenches. In the final form, they give explicit dependence of the wall current on the plasma pressure and current. A comparison with numerical results of Villone et al. [F. Villone, G. Ramogida, G. Rubinacci, Fusion Eng. Des. 93, 57 (2015)] for IGNITOR is performed. Our analysis confirms the importance of the effects described there. The estimates show that the disruption-induced poloidal currents in the wall should be necessarily taken into account in the studies of disruptions and disruption mitigation in ITER.

  5. Vascular wall stress during intravascular optical coherence tomography imaging

    Science.gov (United States)

    Sun, Cuiru; Yang, Victor

    2015-03-01

    Biomechanical properties of arterial wall is crucial for understanding the changes in the cardiovascular system. Catheters are used during intravascular optical coherence tomography (IVOCT) imaging. The presence of a catheter alters the flow field, pressure distribution and frictional resistance to flow in an artery. In this paper, we first study the transmural stress distribution of the catheterized vessel. COMSOL (COMSOL 4.4) was used to simulate the blood flow induced deformation in a catheterized vessel. Blood is modeled as an incompressible Newtonian fluid. Stress distribution from an three-layer vascular model with an eccentric catheter are simulated, which provides a general idea about the distribution of the displacement and the stress. Optical coherence elastography techniques were then applied to porcine carotid artery samples to look at the deformation status of the vascular wall during saline or water injection. Preliminary simulation results show nonuniform stress distribution in the circumferential direction of the eccentrically catheterized vascular model. Three strain rate methods were tested for intravascular OCE application. The tissue Doppler method has the potential to be further developed to image the vascular wall biomechnical properties in vivo. Although results in this study are not validated quantitatively, the experiments and methods may be valuable for intravascular OCE studies, which may provide important information for cardiovascular disease prevention, diagnosis and treatment.

  6. Significance of fluid-structure interaction phenomena for containment response to ex-vessel steam explosions

    Energy Technology Data Exchange (ETDEWEB)

    Almstroem, H.; Sundel, T. [National Defence Research Establishment, Stockholm (Sweden); Frid, W.; Engelbrektson, A.

    1998-01-01

    When studying the structural response of a containment building to ex-vessel steam explosion loads, a two-step procedure is often used. In the first step of this procedure the structures are treated as rigid and the pressure-time history generated by the explosion at the rigid wall is calculated. In the second step the calculated pressure is applied to the structures. The obvious weakness of the two-step procedure is that it does not correspond to the real dynamic behaviour of the fluid-structure system. The purpose of this paper is to identify and evaluate the relevant fluid-structure interaction phenomena. This is achieved through direct treatment of the explosion process and the structural response. The predictions of a direct and two-step treatment are compared for a BWR Mark II containment design, consisting of two concentric walls interacting with water masses in the central and annular pools. It is shown that the two-step approach leads to unrealistic energy transfer in the containment system studied, and to significant overestimation of the deflection of the containment wall. As regards the pedestal wall, the direct method analysis shows that the flexibility of this wall affects the pressure-time history considerably. Three load types have been identified for this wall namely shock load, water blow as a result of water cavitation, and hydrodynamic load. Reloading impulse due to cavitation phenomena plays an important role as it amounts to about 40% of the total impulse load. Investigation of the generality of the cavitation phenomena in the context of ex-vessel steam explosion loads was outside the scope of this work. (author)

  7. Significance of fluid-structure interaction phenomena for containment response to ex-vessel steam explosions

    Energy Technology Data Exchange (ETDEWEB)

    Almstroem, H.; Sundel, T. (Nat. Defence Res. Establ., Tumba (Sweden)); Frid, W. (Swedish Nuclear Power Inspectorate, SE-10658, Stockholm (Sweden)); Engelbrektson, A. (VBB/SWECO, Box 34044, SE-10026, Stockholm (Sweden))

    1999-05-01

    When studying the structural response of a containment building to ex-vessel steam explosion loads, a two-step procedure is often used. In the first step of this procedure the structures are treated as rigid and the pressure-time history generated by the explosion, at the rigid wall, is calculated. In the second step the calculated pressure is applied to the structures. The obvious weakness of the two-step procedure is that it does not correspond to the real dynamic behaviour of the fluid-structure system. The purpose of this paper is to identify and evaluate the relevant fluid-structure interaction phenomena. This is achieved through direct treatment of the explosion process and the structural response. The predictions of a direct and two-step treatment are compared for a BWR Mark II containment design, consisting of two concentric walls interacting with water masses in the central and annular pools. It is shown that the two-step approach leads to unrealistic energy transfer in the containment system studied and to significant overestimation of the deflection of the containment wall. As regards the pedestal wall, the direct method analysis shows that the flexibility of this wall affects the pressure-time history considerably. Three load types have been identified for this wall namely shock load, water blow as a result of water cavitation, and hydrodynamic load. Reloading impulse due to cavitation phenomena plays an important role as it amounts to [approx]40% of the total impulse load. Investigation of the generality of the cavitation phenomena in the context of ex-vessel steam explosion loads was outside the scope of this work. (orig.) 5 refs.

  8. Vessel discoloration detection in malarial retinopathy

    Science.gov (United States)

    Agurto, C.; Nemeth, S.; Barriga, S.; Soliz, P.; MacCormick, I.; Taylor, T.; Harding, S.; Lewallen, S.; Joshi, V.

    2016-03-01

    Cerebral malaria (CM) is a life-threatening clinical syndrome associated with malarial infection. It affects approximately 200 million people, mostly sub-Saharan African children under five years of age. Malarial retinopathy (MR) is a condition in which lesions such as whitening and vessel discoloration that are highly specific to CM appear in the retina. Other unrelated diseases can present with symptoms similar to CM, therefore the exact nature of the clinical symptoms must be ascertained in order to avoid misdiagnosis, which can lead to inappropriate treatment and, potentially, death. In this paper we outline the first system to detect the presence of discolored vessels associated with MR as a means to improve the CM diagnosis. We modified and improved our previous vessel segmentation algorithm by incorporating the `a' channel of the CIELab color space and noise reduction. We then divided the segmented vasculature into vessel segments and extracted features at the wall and in the centerline of the segment. Finally, we used a regression classifier to sort the segments into discolored and not-discolored vessel classes. By counting the abnormal vessel segments in each image, we were able to divide the analyzed images into two groups: normal and presence of vessel discoloration due to MR. We achieved an accuracy of 85% with sensitivity of 94% and specificity of 67%. In clinical practice, this algorithm would be combined with other MR retinal pathology detection algorithms. Therefore, a high specificity can be achieved. By choosing a different operating point in the ROC curve, our system achieved sensitivity of 67% with specificity of 100%.

  9. Wall Art

    Science.gov (United States)

    McGinley, Connie Q.

    2004-01-01

    The author of this article, an art teacher at Monarch High School in Louisville, Colorado, describes how her experience teaching in a new school presented an exciting visual challenge for an art teacher--monotonous brick walls just waiting for decoration. This school experienced only minimal instances of graffiti, but as an art teacher, she did…

  10. [Polyurethane vessels for microvascular surgical training to reduce animal use].

    Science.gov (United States)

    Meier, Sonja A; Lang, Axel; Beer, Gertrude M

    2004-01-01

    Systematic training of the manual skills is inevitable in learning microsurgery. Generally, first exercises are done on two-dimensional models, then the training continues on animals. With the growing ethical awareness, the obligation to protect animals and the stricter animal protection laws, realistic three-dimensional models have become necessary for training of microsurgery. However, the available alternatives all have certain disadvantages. We tested vessels made of polyurethane for microvascular surgical training and compared them to the available three-dimensional synthetic alternatives. Rose-coloured (arteries) or blue (veins), opaque vessels with a minimal wall thickness of 0.12 mm and a minimal internal diameter of 1 mm are used. To mimic the surgical access and the depth of the operative field, the vessels can be embedded in a synthetic box with or without a cap. The completed anastomosis is checked by injection of a coloured fluid. The consistency and the variable relation of the thickness of the wall to the internal diameter very closely reflect the biological situation. Even training on very fragile venous walls is possible in all manners. After completion of anastomosis the vessels can be opened longitudinally to check the patency of the anastomotic site. The described polyurethane vessels are very suitable for microsurgical training as a useful step between the two-dimensional model and the animal. The number of animals required for microsurgical training can clearly be reduced by the use of such synthetic polyurethane vessels.

  11. 2013 Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  12. 2011 Passenger Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  13. 2011 Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  14. 2013 Passenger Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  15. 2013 Tanker Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  16. 2013 Cargo Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  17. High Performance Marine Vessels

    CERN Document Server

    Yun, Liang

    2012-01-01

    High Performance Marine Vessels (HPMVs) range from the Fast Ferries to the latest high speed Navy Craft, including competition power boats and hydroplanes, hydrofoils, hovercraft, catamarans and other multi-hull craft. High Performance Marine Vessels covers the main concepts of HPMVs and discusses historical background, design features, services that have been successful and not so successful, and some sample data of the range of HPMVs to date. Included is a comparison of all HPMVs craft and the differences between them and descriptions of performance (hydrodynamics and aerodynamics). Readers will find a comprehensive overview of the design, development and building of HPMVs. In summary, this book: Focuses on technology at the aero-marine interface Covers the full range of high performance marine vessel concepts Explains the historical development of various HPMVs Discusses ferries, racing and pleasure craft, as well as utility and military missions High Performance Marine Vessels is an ideal book for student...

  18. Cheboygan Vessel Base

    Data.gov (United States)

    Federal Laboratory Consortium — Cheboygan Vessel Base (CVB), located in Cheboygan, Michigan, is a field station of the USGS Great Lakes Science Center (GLSC). CVB was established by congressional...

  19. Maury Journals - US Vessels

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — U.S. vessels observations, after the 1853 Brussels Conference that set International Maritime Standards, modeled after Maury Marine Standard Observations.

  20. 2011 Cargo Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  1. 2011 Tanker Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  2. 2013 Fishing Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  3. Coastal Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains catch (landed catch) and effort for fishing trips made by vessels that have been issued a Federal permit for the Gulf of Mexico reef fish,...

  4. LANL Robotic Vessel Scanning

    Energy Technology Data Exchange (ETDEWEB)

    Webber, Nels W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-25

    Los Alamos National Laboratory in J-1 DARHT Operations Group uses 6ft spherical vessels to contain hazardous materials produced in a hydrodynamic experiment. These contaminated vessels must be analyzed by means of a worker entering the vessel to locate, measure, and document every penetration mark on the vessel. If the worker can be replaced by a highly automated robotic system with a high precision scanner, it will eliminate the risks to the worker and provide management with an accurate 3D model of the vessel presenting the existing damage with the flexibility to manipulate the model for better and more in-depth assessment.The project was successful in meeting the primary goal of installing an automated system which scanned a 6ft vessel with an elapsed time of 45 minutes. This robotic system reduces the total time for the original scope of work by 75 minutes and results in excellent data accumulation and transmission to the 3D model imaging program.

  5. Correlations of coronary plaque wall thickness with wall pressure and wall pressure gradient: a representative case study

    Directory of Open Access Journals (Sweden)

    Liu Biyue

    2012-07-01

    Full Text Available Abstract Background There are two major hemodynamic stresses imposed at the blood arterial wall interface by flowing blood: the wall shear stress (WSS acting tangentially to the wall, and the wall pressure (WP acting normally to the wall. The role of flow wall shear stress in atherosclerosis progression has been under intensive investigation, while the impact of blood pressure on plaque progression has been under-studied. Method The correlations of wall thickness (WT with wall pressure (WP, blood pressure on the lumen wall and spatial wall pressure gradient (WPG in a human atherosclerotic right coronary artery were studied. The pulsatile blood flow was simulated using a three dimensional mathematical model. The blood was treated as an incompressible viscous non-Newtonian fluid. The geometry of the artery was re-constructed using an in vivo intravascular ultrasound (IVUS 44-slice dataset obtained from a patient with consent obtained. The WT, the WP and the WPG were averaged on each slice, respectively, and Pearson correlation analysis was performed on slice averaged base. Each slice was then divided into 8 segments and averaged vessel WT, WP and WPG were collected from all 352 segments for correlation analysis. Each slice was also divided into 2 segments (inner semi-wall of bend and outer semi-wall of bend and the correlation analysis was performed on the 88 segments. Results Under mean pressure, the Pearson coefficient for correlation between WT and WP was r = − 0.52 (p  Conclusions Results from this representative case report indicated that plaque wall thickness correlated negatively with wall pressure (r = −0.81 by slice and positively with wall pressure gradient (r = 0.45. The slice averaged WT has a strong linear relationship with the slice averaged WP. Large-scale patient studies are needed to further confirm our findings.

  6. [Microsurgical blood vessel sutures using the so-called fibrin adhesive].

    Science.gov (United States)

    Meyermann, R; Ahyai, A; Pini, C

    1982-01-01

    Since the development of microvascular surgery by Jacobson and Suarez, adaptation of vessel ends of less than 1 mm diameter has been performed by means of 8-10 interrupted sutures. Even the finest suture material, however, produces a foreign body reaction. In addition, necrosis of the media can be seen after insertion of interrupted sutures. After the initial demonstration in 1940 that divided nerves could be successfully rejoined by means of factors from the blood coagulation system, this technique was introduced to microsurgery in 1977. The present investigation was carried out on 50 end-to-end anastomoses in rat common carotid arteries. Subsequently, the healing process was studied by light and electron microscopy. The adhesive used was fibrinogen cryoprecipitate (Fibrinkleber-Human-Immuno), which polymerises after simultaneous application of thrombin. Electron microscopy shows no basic difference between the healing after this technique and the healing process after trauma to the vessel wall. This method, however, prevents regional necrosis of the vessel wall and reduces intimal thickening. The condition of the intimal lining appears better than in sutured anastomoses. The question, whether this change is due only to the absence of sutures or due also to application of fibrinogen, cannot be answered, however.

  7. Nuclear reactor having a polyhedral primary shield and removable vessel insulation

    Science.gov (United States)

    Ekeroth, Douglas E.; Orr, Richard

    1993-01-01

    A nuclear reactor is provided having a generally cylindrical reactor vessel disposed within an opening in a primary shield. The opening in the primary shield is defined by a plurality of generally planar side walls forming a generally polyhedral-shaped opening. The reactor vessel is supported within the opening in the primary shield by reactor vessel supports which are in communication and aligned with central portions of some of the side walls. The reactor vessel is connected to the central portions of the reactor vessel supports. A thermal insulation polyhedron formed from a plurality of slidably insertable and removable generally planar insulation panels substantially surrounds at least a portion of the reactor vessel and is disposed between the reactor vessel and the side walls of the primary shield. The shape of the insulation polyhedron generally corresponds to the shape of the opening in the primary shield. Reactor monitoring instrumentation may be mounted in the corners of the opening in the primary shield between the side walls and the reactor vessel such that insulation is not disposed between the instrumentation and the reactor vessel.

  8. Liver vessel segmentation based on extreme learning machine.

    Science.gov (United States)

    Zeng, Ye Zhan; Zhao, Yu Qian; Liao, Miao; Zou, Bei Ji; Wang, Xiao Fang; Wang, Wei

    2016-05-01

    Liver-vessel segmentation plays an important role in vessel structure analysis for liver surgical planning. This paper presents a liver-vessel segmentation method based on extreme learning machine (ELM). Firstly, an anisotropic filter is used to remove noise while preserving vessel boundaries from the original computer tomography (CT) images. Then, based on the knowledge of prior shapes and geometrical structures, three classical vessel filters including Sato, Frangi and offset medialness filters together with the strain energy filter are used to extract vessel structure features. Finally, the ELM is applied to segment liver vessels from background voxels. Experimental results show that the proposed method can effectively segment liver vessels from abdominal CT images, and achieves good accuracy, sensitivity and specificity. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  9. Wall reflection modeling for charge exchange recombination spectroscopy (CXRS) measurements on Textor and ITER

    NARCIS (Netherlands)

    Banerjee, S.; Vasu, P.; von Hellermann, M.; Jaspers, R. J. E.

    2010-01-01

    Contamination of optical signals by reflections from the tokamak vessel wall is a matter of great concern. For machines such as ITER and future reactors, where the vessel wall will be predominantly metallic, this is potentially a risk factor for quantitative optical emission spectroscopy. This is,

  10. Wall Layers

    Science.gov (United States)

    1992-01-14

    Sydney, Australia. December 6, 1990. Lumley, J. L. A dynamical-systems-theory approach to the wall region. Environmental Engineering Laboratory, CSIRO...Nonlinear Science. Holmes, P. Editor in Chief, Nonlinear Scinece Today. Holmes, P. Reviewer for Physica D, J. Sound Vib., J. Phys., Q. Appl. Math, Phys...Spring, 1994; Organizing committee member. Holmes, P. Editorial Board Member: Archive for Rational Mechanics and Analysis; Journal of Nonlinear Scinece

  11. CLIMBING WALL

    CERN Multimedia

    1999-01-01

    The FIRE AND RESCUE Group of TIS Commission informs that the climbing wall in the yard of the Fire-fighters Station, is intended for the sole use of the members of that service, and recalls that access to this installation is forbidden for safety reasons to all persons not belonging to the Service.CERN accepts no liability for damage or injury suffered as a result of failure to comply with this interdiction.TIS/DI

  12. Genetic inactivation of IL-1 signaling enhances atherosclerotic plaque instability and reduces outward vessel remodeling in advanced atherosclerosis in mice

    Science.gov (United States)

    Alexander, Matthew R.; Moehle, Christopher W.; Johnson, Jason L.; Yang, Zhengyu; Lee, Jae K.; Jackson, Christopher L.; Owens, Gary K.

    2011-01-01

    Clinical complications of atherosclerosis arise primarily as a result of luminal obstruction due to atherosclerotic plaque growth, with inadequate outward vessel remodeling and plaque destabilization leading to rupture. IL-1 is a proinflammatory cytokine that promotes atherogenesis in animal models, but its role in plaque destabilization and outward vessel remodeling is unclear. The studies presented herein show that advanced atherosclerotic plaques in mice lacking both IL-1 receptor type I and apolipoprotein E (Il1r1–/–Apoe–/– mice) unexpectedly exhibited multiple features of plaque instability as compared with those of Il1r1+/+Apoe–/– mice. These features included reduced plaque SMC content and coverage, reduced plaque collagen content, and increased intraplaque hemorrhage. In addition, the brachiocephalic arteries of Il1r1–/–Apoe–/– mice exhibited no difference in plaque size, but reduced vessel area and lumen size relative to controls, demonstrating a reduction in outward vessel remodeling. Interestingly, expression of MMP3 was dramatically reduced within the plaque and vessel wall of Il1r1–/–Apoe–/– mice, and Mmp3–/–Apoe–/– mice showed defective outward vessel remodeling compared with controls. In addition, MMP3 was required for IL-1–induced SMC invasion of Matrigel in vitro. Taken together, these results show that IL-1 signaling plays a surprising dual protective role in advanced atherosclerosis by promoting outward vessel remodeling and enhancing features of plaque stability, at least in part through MMP3-dependent mechanisms. PMID:22201681

  13. Structural Alterations of the Glomerular Wall And Vessels in Early ...

    African Journals Online (AJOL)

    The second group of 20 (the experimental group) was injected intraperitoneally by a single dose of streptozotocin to induce hyperglycemia. Rats were sacrificed after ten days, two months, and four months. Five rats at two months of age with hyperglycemia were treated with insulin for eight weeks. Renal tissues were ...

  14. Microsurgical Training using Reusable Human Vessels from Discarded Tissues in Lymph Node Dissection

    Directory of Open Access Journals (Sweden)

    Naohiro Ishii

    2016-11-01

    Full Text Available The use of human vessels at the beginning of microsurgery training is highly recommended. But vessels with the appropriate length for training are not often obtained. Whether these vessels may be reused for training has not been reported. Accordingly, we harvested vessels from discarded tissues in lymph node dissection and demonstrated that vascular anastomosis training using the same human vessels several times is possible by placing the vessels in a freezer and defrosting them with hot water. Vascular walls can be stored for microsurgical training until about 4 years after harvest, as shown in the gross appearance and histologic findings of our preserved vessels. We recommend the technique presented here for the longterm reuse of human vessels for microsurgery training that closely resembles real procedures.

  15. Enhancing supply vessel safety

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    A supply-vessel bridge installation consists of a navigating bridge and a control position aft, from which operators control the ship when close to rigs or platforms, and operate winches and other loading equipment. The international Convention for Safety of I Ale at Sea (SOLAS) does not regulate the layout, so design varies to a large degree, often causing an imperfect working environment. As for other types of ships, more than half the offshore service vessel accidents at sea are caused by bridge system failures. A majority can be traced back to technical design, and operational errors. The research and development project NAUT-OSV is a response to the offshore industry's safety concerns. Analysis of 24 incidents involving contact or collision between supply vessels and offshore installations owned or operated by Norwegian companies indicated that failures in the bridge system were often the cause.

  16. Purification of Mouse Brain Vessels.

    Science.gov (United States)

    Boulay, Anne-Cécile; Saubaméa, Bruno; Declèves, Xavier; Cohen-Salmon, Martine

    2015-11-10

    In the brain, most of the vascular system consists of a selective barrier, the blood-brain barrier (BBB) that regulates the exchange of molecules and immune cells between the brain and the blood. Moreover, the huge neuronal metabolic demand requires a moment-to-moment regulation of blood flow. Notably, abnormalities of these regulations are etiological hallmarks of most brain pathologies; including glioblastoma, stroke, edema, epilepsy, degenerative diseases (ex: Parkinson's disease, Alzheimer's disease), brain tumors, as well as inflammatory conditions such as multiple sclerosis, meningitis and sepsis-induced brain dysfunctions. Thus, understanding the signaling events modulating the cerebrovascular physiology is a major challenge. Much insight into the cellular and molecular properties of the various cell types that compose the cerebrovascular system can be gained from primary culture or cell sorting from freshly dissociated brain tissue. However, properties such as cell polarity, morphology and intercellular relationships are not maintained in such preparations. The protocol that we describe here is designed to purify brain vessel fragments, whilst maintaining structural integrity. We show that isolated vessels consist of endothelial cells sealed by tight junctions that are surrounded by a continuous basal lamina. Pericytes, smooth muscle cells as well as the perivascular astrocyte endfeet membranes remain attached to the endothelial layer. Finally, we describe how to perform immunostaining experiments on purified brain vessels.

  17. Multiple large vessel aneurysmal formation in HIV-infected patients

    African Journals Online (AJOL)

    2017-11-14

    Nov 14, 2017 ... HIV proteins are noted within these lymphocytes, but the exact significance of this abnormality is yet to be defined. Transmural necrosis of the vessel wall occurs because of the probable ischemia and results in weakness and aneurysmal formation. The exact pathogenesis is still unknown. Theories such as ...

  18. GOLD PRESSURE VESSEL SEAL

    Science.gov (United States)

    Smith, A.E.

    1963-11-26

    An improved seal between the piston and die member of a piston-cylinder type pressure vessel is presented. A layer of gold, of sufficient thickness to provide an interference fit between the piston and die member, is plated on the contacting surface of at least one of the members. (AEC)

  19. Pressurized Vessel Slurry Pumping

    Energy Technology Data Exchange (ETDEWEB)

    Pound, C.R.

    2001-09-17

    This report summarizes testing of an alternate ''pressurized vessel slurry pumping'' apparatus. The principle is similar to rural domestic water systems and ''acid eggs'' used in chemical laboratories in that material is extruded by displacement with compressed air.

  20. Osteoid osteoma - the CT vessel sign

    Energy Technology Data Exchange (ETDEWEB)

    Yaniv, Gal; Shabshin, Noga; Sharon, Michal; Garniack, Alex [Sheba Medical Center, Dept. of Diagnostic Imaging, Tel Hashomer (Israel); Liberman, Boaz [Sheba Medical Center, Division of Orthopedics, Tel Hashomer, Sackler School of Medicine, Tel Aviv (Israel); Rimon, Uri [Sheba Medical Center, Dept. of Diagnostic Imaging, Tel Hashomer, Sackler School of Medicine, Tel Aviv (Israel); Eshed, Iris [Sheba Medical Center, Dept. of Diagnostic Imaging, Tel Hashomer, Tel Aviv University Sackler School of Medicine, Tel Aviv (Israel)

    2011-10-15

    To evaluate whether the presence of a feeding vessel in proximity to osteoid osteomas of long bones on multidetector CT (MDCT) can be an adjuvant clue for the diagnosis of osteoid osteoma. Forty-nine CT scans of patients with radiological and clinical diagnosis of osteoid osteoma of long bones and a control group of 20 CT scans of patients with cortical-based lesions other then osteoid osteoma were analyzed. Two radiologists evaluated the CT images in consensus for the presence of a blood vessel in the same axial slices in which the nidus of osteoid osteoma was seen and to determine the incidence. In 39 cases (79.6%) of osteoid osteoma, a blood vessel either entered the nidus (23 patients) or was seen in proximity to it (16 patients). This was significantly different (P<0.05) from the cortical-based lesions, in which only two CT scans (10%) showed a blood vessel in the lesion's proximity. In the majority of osteoid osteoma lesions in long bones, a blood vessel can be seen on MDCT either entering the nidus itself or in its proximity. The role of this vessel in the lesion pathogenesis and whether it improves diagnostic accuracy need further evaluation. (orig.)

  1. Hawaii Abandoned Vessel Inventory, Kauai

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Kauai. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  2. CNMI Abandoned Vessel Inventory, Tinian

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Tinian. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  3. Puerto Rico Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Puerto Rico. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  4. American Samoa Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for American Samoa. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  5. Hawaii Abandoned Vessel Inventory, Oahu

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Oahu, Hawaii. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  6. Hawaii Abandoned Vessel Inventory, Molokai

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Molokai, Hawaii. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  7. CNMI Abandoned Vessel Inventory, Rota

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Rota. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  8. Hawaii Abandoned Vessel Inventory, Lanai

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Lanai. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  9. For-Hire Vessel Directory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Vessel Directory is maintained as the sample frame for the For-Hire Survey. I contains data on for-hire vessels on the Atlantic and Gulf coasts. Data include...

  10. CNMI Abandoned Vessel Inventory, Saipan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Saipan. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  11. Hawaii Abandoned Vessel Inventory, Maui

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Maui. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  12. Vessels in Transit - Web Tool

    Data.gov (United States)

    Department of Transportation — A web tool that provides real-time information on vessels transiting the Saint Lawrence Seaway. Visitors may sort by order of turn, vessel name, or last location in...

  13. Pressure vessel design manual

    Energy Technology Data Exchange (ETDEWEB)

    Moss, D.R.

    1987-01-01

    The first section of the book covers types of loadings, failures, and stress theories, and how they apply to pressure vessels. The book delineates the procedures for designing typical components as well as those for designing large openings in cylindrical shells, ring girders, davits, platforms, bins and elevated tanks. The techniques for designing conical transitions, cone-cylinder intersections, intermediate heads, flat heads, and spherically dished covers are also described. The book covers the design of vessel supports subject to wind and seismic loads and one section is devoted to the five major ways of analyzing loads on shells and heads. Each procedure is detailed enough to size all welds, bolts, and plate thicknesses and to determine actual stresses.

  14. New research vessels

    Science.gov (United States)

    1984-04-01

    Two “new” ocean-going research vessels operated by the Scripps Institution of Oceanography and the National Science Foundation (NSF) will soon begin full-time scientific duties off the coast of California and in the Antarctic, respectively. The 37.5-m Scripps vessel, named Robert Gordon Sprout in honor of the ex-president of the University of California, replaces the smaller ship Ellen B. Scripps, which had served the institution since 1965. The new ship is a slightly modified Gulf Coast workboat. Under the name of Midnight Alaskan, it had been used for high-resolution geophysical surveys in American and Latin American waters by such firms as Arco Oil & Gas, Exxon, Pennzoil, and Racal-Decca before its purchase by Scripps from a Lousiana chartering firm last summer.

  15. Large vessel vasculitides

    OpenAIRE

    Morović-Vergles, Jadranka; Pukšić, Silva; Gudelj Gračanin, Ana

    2013-01-01

    Large vessel vasculitis includes Giant cell arteritis and Takayasu arteritis. Giant cell arteritis is the most common form of vasculitis affect patients aged 50 years or over. The diagnosis should be considered in older patients who present with new onset of headache, visual disturbance, polymyalgia rheumatica and/or fever unknown cause. Glucocorticoides remain the cornerstone of therapy. Takayasu arteritis is a chronic panarteritis of the aorta ant its major branches presenting commonly in y...

  16. Very Versatile Vessel

    Science.gov (United States)

    2009-09-01

    data. This source provides information on aluminum hydrofoil vessels without the added weight of foil structures. The composite armor around the...seating compartment. The sides should also limit wave splash on the deck. The freeboard should contribute reserve buoyancy , increasing large-angle and...Resistance, Powering, and Propulsion Savitsky’s Method Since model testing data or other reliable performance data was unavailable for the proposed

  17. Confinement Vessel Assay System: Design and Implementation Report

    Energy Technology Data Exchange (ETDEWEB)

    Frame, Katherine C. [Los Alamos National Laboratory; Bourne, Mark M. [Los Alamos National Laboratory; Crooks, William J. [Los Alamos National Laboratory; Evans, Louise [Los Alamos National Laboratory; Mayo, Douglas R. [Los Alamos National Laboratory; Gomez, Cipriano D. [Retired CMR-OPS: OPERATIONS; Miko, David K. [Los Alamos National Laboratory; Salazar, William R. [Los Alamos National Laboratory; Stange, Sy [Los Alamos National Laboratory; Vigil, Georgiana M. [Los Alamos National Laboratory

    2012-07-18

    Los Alamos National Laboratory has a number of spherical confinement vessels remaining from tests involving nuclear materials. These vessels have an inner diameter of 6 feet with 1- to 2-inch thick steel walls. The goal of the Confinement Vessel Disposition (CVD) project is to remove debris and reduce contamination inside the vessels. We have developed a neutron assay system for the purposes of Materials Control and Accountability (MC&A) measurements of the vessel prior to and after cleanout. We present our approach to confronting the challenges in designing, building, and testing such a system. The system was designed to meet a set of functional and operational requirements. A Monte Carlo model was developed to aid in optimizing the detector design as well as to predict the systematic uncertainty associated with confinement vessel measurements. Initial testing was performed to optimize and determine various measurement parameters, and then the system was characterized using {sup 252}Cf placed a various locations throughout the measurement system. Measurements were also performed with a {sup 252}Cf source placed inside of small steel and HDPE shells to study the effect of moderation. These measurements compare favorably with their MCNPX model equivalent, making us confident that we can rely on the Monte Carlo simulation to predict the systematic uncertainty due to variations in response to material that may be localized at different points within a vessel.

  18. Falling walls

    CERN Multimedia

    It was 20 years ago this week that the Berlin wall was opened for the first time since its construction began in 1961. Although the signs of a thaw had been in the air for some time, few predicted the speed of the change that would ensue. As members of the scientific community, we can take a moment to reflect on the role our field played in bringing East and West together. CERN’s collaboration with the East, primarily through links with the Joint Institute for Nuclear Research, JINR, in Dubna, Russia, is well documented. Less well known, however, is the role CERN played in bringing the scientists of East and West Germany together. As the Iron curtain was going up, particle physicists on both sides were already creating the conditions that would allow it to be torn down. Cold war historian Thomas Stange tells the story in his 2002 CERN Courier article. It was my privilege to be in Berlin on Monday, the anniversary of the wall’s opening, to take part in a conference entitled &lsquo...

  19. The evaluation of pressure effects on the ex-vessel cooling for KNGR with MELCOR

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Hwa; Park, Soo Yong; Kim, Dong Ha

    2001-03-01

    In this report, the effect of external vessel cooling on debris coolability and vessel integrity for the KNGR were examined from the two typical pressure range of high(170 bar) and low(5 bar)case using the lower plenum model in MELCOR1.8.4. As the conditions of these calculations, 80 ton of debris was relocated simultaneously into the lower vessel head and the debris relocation temperature from the core region was 2700 K. The decay heat has been assumed to be that of one hour after reactor shutdown. The creep failure of the vessel wall was simulated with 1-D model, which can consider the rapid temperature gradient over the wall thickness during the ex-vessel cooling. From the calculation results, both the coolant temperature and the total amount of coolant mass injected into the cavity are known to be the important factors in determining the time period to keep the external vessel cool. Therefore, a long-term strategy to keep the coolant temperature subcooled throughout the transient is suggested to sustain or prolong the effect of external vessel cooling. Also, it is expected that to keep the primary side at low pressure and to perform the ex-vessel flooding be the essential conditions to sustain the vessel integrity. From MELCOR, the penetration failure always occurs after relocation regardless of the RCS pressure or availability of the external vessel cooling. Therefore, It is expected that the improvement of the model for the penetration tube failure will be necessary.

  20. Design and implementation of visual inspection system handed in tokamak flexible in-vessel robot

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hesheng; Xu, Lifei [Department of Automation, Shanghai Jiao Tong University, Shanghai 200240 (China); Key Laboratory of System Control and Information Processing, Ministry of Education of China (China); Chen, Weidong, E-mail: wdchen@sjtu.edu.cn [Department of Automation, Shanghai Jiao Tong University, Shanghai 200240 (China); Key Laboratory of System Control and Information Processing, Ministry of Education of China (China)

    2016-05-15

    In-vessel viewing system (IVVS) is a fundamental tool among the remote handling systems for ITER, which is used to providing information on the status of the in-vessel components. The basic functional requirement of in-vessel visual inspection system is to perform a fast intervention with adequate optical resolution. In this paper, we present the software and hardware solution, which is designed and implemented for tokamak in-vessel viewing system that installed on end-effector of flexible in-vessel robot working under vacuum and high temperature. The characteristic of our in-vessel viewing system consists of two parts: binocular heterogeneous vision inspection tool and first wall scene emersion based augment virtuality. The former protected with water-cooled shield is designed to satisfy the basic functional requirement of visual inspection system, which has the capacity of large field of view and high-resolution for detection precision. The latter, achieved by overlaying first wall tiles images onto virtual first wall scene model in 3D virtual reality simulation system, is designed for convenient, intuitive and realistic-looking visual inspection instead of viewing the status of first wall only by real-time monitoring or off-line images sequences. We present the modular division of system, each of them in smaller detail, and go through some of the design choices according to requirements of in-vessel visual inspection task.

  1. ITER Vacuum Vessel design and construction

    Energy Technology Data Exchange (ETDEWEB)

    Ioki, K., E-mail: Kimihiro.Ioki@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Choi, C.H.; Daly, E.; Dani, S.; Davis, J.; Giraud, B.; Gribov, Y.; Hamlyn-Harris, C. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Jones, L. [F4E, c/Josep Pla, n.2, Torres Diagonal Litoral, Edificio B3, E-08019 Barcelona (Spain); Jun, C. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Kim, B.C. [NFRI, 52 Yeoeundong Yuseonggu, Daejeon 305-333 (Korea, Republic of); Kuzmin, E. [NTC ' Sintez' , Efremov Inst., 189631 Metallostroy, St. Petersburg (Russian Federation); Le Barbier, R.; Martinez, J.-M. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Pathak, H. [ITER-India, A-29, GIDC Electronic Estate, Sector -25, Gandhinagar 382025 (India); Preble, J.; Reich, J. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Sa, J.W. [NFRI, 52 Yeoeundong Yuseonggu, Daejeon 305-333 (Korea, Republic of); Terasawa, A.; Utin, Yu. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); and others

    2012-08-15

    After implementing a few design modifications (referred to as the 'Modified Reference Design') in 2009, the Vacuum Vessel (VV) design had been stabilized. The VV design is being finalized, including interface components such as support rails and feedthroughs for the in-vessel coils. It is necessary to make adjustments to the locations of the blanket supports and manifolds to accommodate design modifications to the in-vessel coils. The VV support design is also being finalized considering a structural simplification. Design of the in-wall shielding (IWS) has progressed, considering the assembly methods and the required tolerances. The detailed layout of ferritic steel plates and borated steel plates was optimized based on the toroidal field ripple analysis. A dynamic test on the inter-modular key to support the blanket modules was performed to measure the dynamic amplification factor (DAF). An R and D program has started to select and qualify the welding and cutting processes for the port flange lip seal. The ITER VV material 316 L(N) IG was already qualified and the Modified Reference Design was approved by the Agreed Notified Body (ANB) in accordance with the Nuclear Pressure Equipment Order procedure.

  2. Transport of divalent cations: cation exchange capacity of intact xylem vessels.

    Science.gov (United States)

    Van de Geijn, S C; Petit, C M

    1979-12-01

    The cation exchange capacity of the intact xylem vessels in cut shoots of papyrus (Cyperus papyrus spec.) has been determined. The cation exchange capacity is independent of the cation concentration in the transpiration stream, and is equal for Ca and Co. The high value of the cation exchange capacity (0.6 to 1 x 10(-7) equivalents per square centimeter vessel wall surface) leads to the hypothesis that the porous structure of the vessel wall, and not only the inner vessel wall surface, acts as a cation exchanger.Differences between anion ([(32)P]phosphate, [(45)Ca]EDTA(2-), [(115)Cd(m)]-EDTA(2-)), and cation ([(45)Ca](2+), [(115)Cd(m)](2+)) movement are explained in terms of transport with the transpiration flux or by exchange reactions. The competition between exchange sites and natural or synthetic ligands for the divalent cations is discussed.

  3. Ultrasonography of chest wall lesion

    Energy Technology Data Exchange (ETDEWEB)

    Park, Cheol Min; Kim, C. H.; Cha, I. H.; Chung, K. B.; Ser, W. H.; Choi, Y. H. [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1989-12-15

    Thirty-one patients with chest wall diseases were studied with ultrasound to evaluate its role in chest wall lesions. There were eight infectious conditions, 9 benign tumors, 11 malignant lesions and 3 miscellaneous cases. Diffuse chest wall thickening with heterogeneous echogenicity and obliteration of subcutaneous fat layer are findings of acute infection. In cases of tuberculous smpyema necessitates, pleural abnormality extended to the chest wall through intercostal space. Benign tumors were well demarcated, except in 4 cases of lipoma/lipomatosis. Malignant lesions showed irregular soft tissue masses, bone destruction, pleural effusion and subcutaneous invasion. Multiple enlarged lymph nodes were also shown. Ultrasound can demonstrate te internal structure, extent, depth and associated findings such as pleural effusion, bone destruction and peripheral lung involvement. Ultrasound is not only safe, non-invasive and an effective diagnostic imaging modality for chest wall disease, but can also guide aspiration or biopsy for pathologic diagnosis

  4. Towards cavitation-enhanced permeability in blood vessel on a chip

    Science.gov (United States)

    De Luca, R.; Silvani, G.; Scognamiglio, C.; Sinibaldi, G.; Peruzzi, G.; Chinappi, M.; Kiani, M. F.; Casciola, C. M.

    2017-08-01

    The development of targeted delivery systems releasing pharmaceutical agents directly at the desired site of action may improve their therapeutic efficiency while minimizing damage to healthy tissues, toxicity to the patient and drug waste. In this context, we have developed a bio-inspired microdevice mimicking the tumour microvasculature which represents a valuable tool for assessing the enhancement of blood vessel permeability due to cavitation. This novel system allows us to investigate the effects of ultrasound-driven microbubbles that temporarily open the endothelial intercellular junctions allowing drug to extravasate blood vessels into tumour tissues. The blood vessel on a chip consists of a tissue chamber and two independent vascular channels (width 200 µm, height 100 µm, length 2762 µm) cultured with endothelial cells placed side-by-side and separated by a series of 3 µm pores. Its geometry and dimensions mimic the three-dimensional morphology, size and flow characteristics of microvessels in vivo. The early stage of this project had a twofold objective: 1. To define the protocol for culturing of Human Umbilical Vein Endothelial Cells (HUVECs) within the vascular channel; 2. To develop a fluorescence based microscopy technique for measuring permeability. We have developed a reliable and reproducible protocol to culture endothelial cells within the artificial vessels in a realistic manner: HUVECs show the typical elongated shape in the direction of flow, exhibit tight junction formation and form a continuous layer with a central lumen that completely covers the channels wall. As expected, the permeability of cell-free device is higher than the one cultured with HUVECs in the vascular channels. The proposed blood vessel on a chip and the permeability measurement protocol have a significant potential to allow for the study of cavitation-enhanced permeability of the endothelium and improve efficiency in screening drug delivery systems.

  5. Design assessment for manufacturability of supporting structures for IWS and ELM coil of ITER vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yu-Gyeong, E-mail: aspirany@hhi.co.kr [Hyundai Heavy Industries Co., Ltd., Dong-gu, Ulsan (Korea, Republic of); Hong, Yun-Seok; Kwon, Tae-Hoon; Jung, Yung-Jin [Hyundai Heavy Industries Co., Ltd., Dong-gu, Ulsan (Korea, Republic of); Ahn, Hee-Jae; Kim, Byung-Chul; Lee, Young-Ju [National Fusion Research Institute, 113 Gwahangno, Yuseong-gu, Daejeon-si 305-333 (Korea, Republic of)

    2013-10-15

    Highlights: ► A “bridge type” welding method was proposed for IWS rib and ELM coil supports. ► This method could reduce the welding distortion and increase the manufacturability. ► Structural integrity of proposed design was assessed for both P and S type damages. ► Results show that the proposed designs meet the design criteria of RCC-MR. -- Abstract: A vacuum vessel is one of the core facilities of ITER (International Thermonuclear Experimental Reactor) and basically all-welded structure. Korea is responsible for the procurement of sector 1 and 6 of the main vessel. Accordingly, the design review for the fabrication is in progress by ITER Korea and Hyundai Heavy Industries. Due to anticipated manufacturing problems such as the welding distortion, the design of some components of main vessel, IWS (In-Wall Shield) supporting rib and ELM (Edge Localized Mode) coil support, needs to be modified. To release the risk of welding distortion, the welding method called “bridge type” is suggested and the shape of weld joint is adjusted to secure the manufacturability of the issued components. The elastic and limit analyses with fatigue evaluation have been performed under the most critical loading condition to verify the structural integrity of modified design. Analysis results show that the proposed designs meet the design criteria of RCC-MR. The design deviation requests have been submitted to ITER Organization and ANB (Agreed Notified Body) for approval and their verification is currently in progress.

  6. Lymphatic vessels: an emerging actor in atherosclerotic plaque development.

    Science.gov (United States)

    Kutkut, Issa; Meens, Merlijn J; McKee, Thomas A; Bochaton-Piallat, Marie-Luce; Kwak, Brenda R

    2015-01-01

    Atherosclerosis is a chronic inflammatory disease of large- to medium-sized arteries and is the main underlying cause of death worldwide. The lymphatic vasculature is critical for processes that are intimately linked to atherogenesis such as the immune response and cholesterol metabolism. However, whether lymphatic vessels truly contribute to the pathogenesis of atherosclerosis is less clear despite increasing research efforts in this field. PubMed and Ovid MEDLINE databases were searched. In addition, key review articles were screened for relevant original publications. Current knowledge about lymphatic vessels in the arterial wall came from studies that examined the presence and location of such vessels in human atherosclerotic plaque specimens, as well as in a variety of arteries in animal models for atherosclerosis (e.g. rabbits, dogs, rats and mice). Generally, three experimental approaches have been used to investigate the functional role of plaque-associated lymphatic vessels; experimental lymphostasis was used to investigate lymphatic drainage of the arterial wall, and more recently, studies with genetic interventions and/or surgical transplantation have been performed. Lymphatic vessels seem to be mostly present in the adventitial layer of the arterial walls of animals and humans. They are involved in reverse cholesterol transport from atherosclerotic lesions, and arteries with a dense lymphatic network seem naturally protected against atherosclerosis. Lymphangiogenesis is a process that is an important part of the inflammatory loop in atherosclerosis. However, how augmenting or impeding the distribution of lymphatic vessels impacts disease progression remains to be investigated in future studies. © 2014 Stichting European Society for Clinical Investigation Journal Foundation.

  7. Influence of cerebral blood vessel movements on the position of perivascular synapses

    Science.gov (United States)

    DeFelipe, Javier

    2017-01-01

    Synaptic activity is regulated and limited by blood flow, which is controlled by blood vessel dilation and contraction. Traditionally, the study of neurovascular coupling has mainly focused on energy consumption and oxygen delivery. However, the mechanical changes that blood vessel movements induce in the surrounding tissue have not been considered. We have modeled the mechanical changes that movements of blood vessels cause in neighboring synapses. Our simulations indicate that synaptic densities increase or decrease during vascular dilation and contraction, respectively, near the blood vessel walls. This phenomenon may alter the concentration of neurotransmitters and vasoactive substances in the immediate vicinity of the vessel wall and thus may have an influence on local blood flow. PMID:28199396

  8. Have "formal investigations" into fishing vessel losses ceased?

    OpenAIRE

    Reilly, M S

    1987-01-01

    Systematic studies of 618 fishing vessel losses between January 1961 and December 1982 have shown a significantly increased incidence of total losses from 1972 onwards. Comparison of mean pre- and post-1972 rates indicated an increase of 120% from 2.54 to 5.58 losses per 1000 vessels at risk. Parallel examination of the mortality of fishermen from all occupational accidents showed no improvement. For deaths arising from vessel losses alone, the mean crude death rate, for the same periods, inc...

  9. Conformable pressure vessel for high pressure gas storage

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, Kevin L.; Johnson, Kenneth I.; Lavender, Curt A.; Newhouse, Norman L.; Yeggy, Brian C.

    2016-01-12

    A non-cylindrical pressure vessel storage tank is disclosed. The storage tank includes an internal structure. The internal structure is coupled to at least one wall of the storage tank. The internal structure shapes and internally supports the storage tank. The pressure vessel storage tank has a conformability of about 0.8 to about 1.0. The internal structure can be, but is not limited to, a Schwarz-P structure, an egg-crate shaped structure, or carbon fiber ligament structure.

  10. Vessel Traffic Services.

    Science.gov (United States)

    1982-12-01

    Yorker" articles titled Silent Spring by Rachel Carson in 1963 produced a unifying effect, "the sort of rallying point of the movement to protect the...6232, 92d Cong., 1st. sess., 1971, p. 2. 15. Carson , Rachel L. , The Sea Around Us, New York: Oxford Univesity Press, 195-, p. IV. 16. U.S., Congress...Government Printing Office, 1974. 63. Buhler, L. and Geiger, J., Vessel Traffic Data Extraction MethodoloqX, Silver Spring , Maryland, O6erFae-tns

  11. Vanishing corneal vessels

    Science.gov (United States)

    Nicholson, Luke; Chana, Rupinder

    2013-01-01

    We wish to highlight the importance of acknowledging the accompanying effects of topical phenylephrine drops on the eye other than its intended mydriasis. We reported a case of a 92-year-old woman with a corneal graft who was noted to have superficial corneal vascularisation which was not documented previously. After the instillation of topical tropicamide 1% and phenylephrine 2.5%, for funduscopy, the corneal vascularisation was not visible. When reassessed on another visit, tropicamide had no effect on the vessels and only phenylephrine did. We wish to highlight that when reviewing patients in cornea clinics, instilling phenylephrine prior to being seen may mask important corneal vascularisation. PMID:24121816

  12. EFFECT OF 2,6-DICHLOROBENZONITRILE (DCB ON SECONDARY WALL DEPOSITION AND LIGNIFICATION IN THE STEM OF HIBISCUS CANNABINUS L.

    Directory of Open Access Journals (Sweden)

    PRAMOD Sivan

    2013-12-01

    Full Text Available Light and electron microscopic studies were carried out on the secondary xylem of actively growing shoots of Hibiscus cannabinus treated with cellulose synthesis inhibitor 2,6-dichlorobenzonitrile (DCB. Treatment with 20µM DCB induced differentiation of xylem fibres with thin secondary walls and parenchyma cells with abnormal wall thickening and lignification. At concentration above 50 µM resulted in the disappearance of cambial zone, inhibition of secondary wall deposition, lignification of primary walls, deformed vessel walls and dispersed lignin distribution in secondary walls. Transmission electron microscopic study revealed the initiation and formation of large intercellular spaces between the walls of differentiating xylem elements. Abnormal pattern of wall deposition and inhomogeneous lignin distribution was evident in fibres and vessel. The length and width of both fibres and vessel elements were reduced significantly even with lower concentrations of DCB.

  13. Customizable engineered blood vessels using 3D printed inserts.

    Science.gov (United States)

    Pinnock, Cameron B; Meier, Elizabeth M; Joshi, Neeraj N; Wu, Bin; Lam, Mai T

    2016-04-15

    Current techniques for tissue engineering blood vessels are not customizable for vascular size variation and vessel wall thickness. These critical parameters vary widely between the different arteries in the human body, and the ability to engineer vessels of varying sizes could increase capabilities for disease modeling and treatment options. We present an innovative method for producing customizable, tissue engineered, self-organizing vascular constructs by replicating a major structural component of blood vessels - the smooth muscle layer, or tunica media. We utilize a unique system combining 3D printed plate inserts to control construct size and shape, and cell sheets supported by a temporary fibrin hydrogel to encourage cellular self-organization into a tubular form resembling a natural artery. To form the vascular construct, 3D printed inserts are adhered to tissue culture plates, fibrin hydrogel is deposited around the inserts, and human aortic smooth muscle cells are then seeded atop the fibrin hydrogel. The gel, aided by the innate contractile properties of the smooth muscle cells, aggregates towards the center post insert, creating a tissue ring of smooth muscle cells. These rings are then stacked into the final tubular construct. Our methodology is robust, easily repeatable and allows for customization of cellular composition, vessel wall thickness, and length of the vessel construct merely by varying the size of the 3D printed inserts. This platform has potential for facilitating more accurate modeling of vascular pathology, serving as a drug discovery tool, or for vessel repair in disease treatment. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Vasomotion does inhibit mass exchange between axisymmetric blood vessels and tissue.

    Science.gov (United States)

    Payne, S J; Oakes, C N J; Park, C S

    2012-06-07

    Vasomotion, the name given to the physiological phenomenon whereby blood vessel walls exhibit rhythmic oscillations in diameter, is a complex process and very poorly understood. It has been proposed as a mechanism for protecting tissue when perfusion levels are reduced, since it has experimentally been shown to occur more frequently under such conditions. However, no quantitative evidence yet exists for whether the oscillation of the wall actually has any effect on mass transport to tissue. In our previous work, it was shown that the presence of non-linearities in the governing equation could result in a significant change in time-averaged mass transport to tissue: however, it was not possible, due to the limitations of the model, to determine whether time-averaged mass transport increased or decreased. This model is extended in this paper through coupling of the one-dimensional axisymmetric mass transport equations in tissue and blood to quantify the effects of vasomotion on mass transport to tissue. The results show that over a wide parameter range, surrounding those values calculated from experimental data, vasomotion does inhibit mass transport to tissue in a one-dimensional axisymmetric blood vessel by an amount that is predominantly dependent upon the amplitude of oscillation and that increases rapidly at larger oscillation amplitudes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Vessel Sampling and Blood Flow Velocity Distribution With Vessel Diameter for Characterizing the Human Bulbar Conjunctival Microvasculature.

    Science.gov (United States)

    Wang, Liang; Yuan, Jin; Jiang, Hong; Yan, Wentao; Cintrón-Colón, Hector R; Perez, Victor L; DeBuc, Delia C; Feuer, William J; Wang, Jianhua

    2016-03-01

    This study determined (1) how many vessels (i.e., the vessel sampling) are needed to reliably characterize the bulbar conjunctival microvasculature and (2) if characteristic information can be obtained from the distribution histogram of the blood flow velocity and vessel diameter. Functional slitlamp biomicroscope was used to image hundreds of venules per subject. The bulbar conjunctiva in five healthy human subjects was imaged on six different locations in the temporal bulbar conjunctiva. The histograms of the diameter and velocity were plotted to examine whether the distribution was normal. Standard errors were calculated from the standard deviation and vessel sample size. The ratio of the standard error of the mean over the population mean was used to determine the sample size cutoff. The velocity was plotted as a function of the vessel diameter to display the distribution of the diameter and velocity. The results showed that the sampling size was approximately 15 vessels, which generated a standard error equivalent to 15% of the population mean from the total vessel population. The distributions of the diameter and velocity were not only unimodal, but also somewhat positively skewed and not normal. The blood flow velocity was related to the vessel diameter (r=0.23, P<0.05). This was the first study to determine the sampling size of the vessels and the distribution histogram of the blood flow velocity and vessel diameter, which may lead to a better understanding of the human microvascular system of the bulbar conjunctiva.

  16. [Addiction among patients hospitalized due to peripheral vessels disorders].

    Science.gov (United States)

    Wójcik, Alicja; Sodolski, Wojciech; Jaworska, Elzbieta; Borzecki, Andrzej; Brzeski, Zdzisław

    2005-01-01

    The study covered 160 patients - 80 females and 80 males, hospitalised due to arterial and venous vessels disorders. The objective of the study was an attempt to evaluate selected behaviours, such as tobacco smoking, consumption of alcohol and coffee among people with diseases of peripheral vessels. The research tool was a questionnaire form. Participation in the study was voluntary and patients were selected at random. The study showed that 60% of respondents suffered from peripheral vessels disorders, 67.5% of females had venous vessels disorders, and 87.5% of males - arterial vessels disorders. In the total population examined 69.38% of respondents consumed alcohol, 47.5% were current smokers, and 56.88% consumed coffee. The style of life of the people examined may result in the development of peripheral vessel disorders.

  17. 46 CFR 289.2 - Vessels included.

    Science.gov (United States)

    2010-10-01

    ... CONSTRUCTION-DIFFERENTIAL SUBSIDY VESSELS, OPERATING-DIFFERENTIAL SUBSIDY VESSELS AND OF VESSELS SOLD OR ADJUSTED UNDER THE MERCHANT SHIP SALES ACT 1946 § 289.2 Vessels included. Vessels subject to the provisions of this part are: (a) All vessels which may in the future be constructed or sold with construction...

  18. Trends in Tissue Engineering for Blood Vessels

    Directory of Open Access Journals (Sweden)

    Judee Grace Nemeno-Guanzon

    2012-01-01

    Full Text Available Over the years, cardiovascular diseases continue to increase and affect not only human health but also the economic stability worldwide. The advancement in tissue engineering is contributing a lot in dealing with this immediate need of alleviating human health. Blood vessel diseases are considered as major cardiovascular health problems. Although blood vessel transplantation is the most convenient treatment, it has been delimited due to scarcity of donors and the patient’s conditions. However, tissue-engineered blood vessels are promising alternatives as mode of treatment for blood vessel defects. The purpose of this paper is to show the importance of the advancement on biofabrication technology for treatment of soft tissue defects particularly for vascular tissues. This will also provide an overview and update on the current status of tissue reconstruction especially from autologous stem cells, scaffolds, and scaffold-free cellular transplantable constructs. The discussion of this paper will be focused on the historical view of cardiovascular tissue engineering and stem cell biology. The representative studies featured in this paper are limited within the last decade in order to trace the trend and evolution of techniques for blood vessel tissue engineering.

  19. Blood flow reprograms lymphatic vessels to blood vessels.

    Science.gov (United States)

    Chen, Chiu-Yu; Bertozzi, Cara; Zou, Zhiying; Yuan, Lijun; Lee, John S; Lu, MinMin; Stachelek, Stan J; Srinivasan, Sathish; Guo, Lili; Vicente, Andres; Vincente, Andres; Mericko, Patricia; Levy, Robert J; Makinen, Taija; Oliver, Guillermo; Kahn, Mark L

    2012-06-01

    Human vascular malformations cause disease as a result of changes in blood flow and vascular hemodynamic forces. Although the genetic mutations that underlie the formation of many human vascular malformations are known, the extent to which abnormal blood flow can subsequently influence the vascular genetic program and natural history is not. Loss of the SH2 domain-containing leukocyte protein of 76 kDa (SLP76) resulted in a vascular malformation that directed blood flow through mesenteric lymphatic vessels after birth in mice. Mesenteric vessels in the position of the congenital lymphatic in mature Slp76-null mice lacked lymphatic identity and expressed a marker of blood vessel identity. Genetic lineage tracing demonstrated that this change in vessel identity was the result of lymphatic endothelial cell reprogramming rather than replacement by blood endothelial cells. Exposure of lymphatic vessels to blood in the absence of significant flow did not alter vessel identity in vivo, but lymphatic endothelial cells exposed to similar levels of shear stress ex vivo rapidly lost expression of PROX1, a lymphatic fate-specifying transcription factor. These findings reveal that blood flow can convert lymphatic vessels to blood vessels, demonstrating that hemodynamic forces may reprogram endothelial and vessel identity in cardiovascular diseases associated with abnormal flow.

  20. Heat-pipes-based first wall

    Energy Technology Data Exchange (ETDEWEB)

    Kovalenko, V. [Research and Development Institute of Power Engineering, PO Box 788, Moscow 101000 (Russian Federation); Khripunov, V. [Russian Research Center `Kurchatov Institute`, Nuclear Fusion Institute, Kurchatov Square, Moscow 123182 (Russian Federation); Antipenkov, A. [Research and Development Institute of Power Engineering, PO Box 788, Moscow 101000 (Russian Federation); Ulianov, A. [State Enterprise `Krasnaya Zvezda`, Electrolytny pr-d., 1a, Moscow 115230 (Russian Federation)

    1995-03-01

    Feasibilities of heat pipes application for the heat transfer out of plasma facing components in test and power fusion reactors are discussed. Based on the space technology and practice the ``hot`` ITER first wall with liquid metal and water heat pipes are proposed in two options: heat-pipes and vapor-chamber options. Other high heat loading in-vessel elements such as divertor target and limiter can be provided by effective and reliable heat pipe cooling systems. (orig.).

  1. Do quantitative vessel and pit characters account for ion-mediated changes in the hydraulic conductance of angiosperm xylem?

    Science.gov (United States)

    Jansen, Steven; Gortan, Emmanuelle; Lens, Frederic; Lo Gullo, Maria Assunta; Salleo, Sebastiano; Scholz, Alexander; Stein, Anke; Trifilò, Patrizia; Nardini, Andrea

    2011-01-01

    • The hydraulic conductance of angiosperm xylem has been suggested to vary with changes in sap solute concentrations because of intervessel pit properties. • The magnitude of the 'ionic effect' was linked with vessel and pit dimensions in 20 angiosperm species covering 13 families including six Lauraceae species. • A positive correlation was found between ionic effect and vessel grouping parameters, especially the portion of vessel walls in contact with neighbouring vessels. Species with intervessel contact fraction (F(C)) values 0.1 exhibited a response between 10% and 32%. The ionic effect increased linearly with the mean fraction of the total vessel wall area occupied by intervessel pits as well as with the intervessel contact length. However, no significant correlation occurred between the ionic effect and total intervessel pit membrane area per vessel, vessel diameter, vessel length, vessel wall area, and intervessel pit membrane thickness. • Quantitative vessel and pit characters are suggested to contribute to interspecific variation of the ionic effect, whereas chemical properties of intervessel pit membranes are likely to play an additional role. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

  2. Application of ion beam irradiated ePTFE to repair small vessel injuries

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, N. [Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162-8601 (Japan) and Beam Application Team, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)]. E-mail: norikichi@ionbeams.riken.jp; Suzuki, Y. [Beam Application Team, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Ujiie, H. [Tokyo Women' s Medical University, 8-1 Kawada-cho, Shinjuku, Tokyo 162-8666 (Japan); Hori, T. [Tokyo Women' s Medical University, 8-1 Kawada-cho, Shinjuku, Tokyo 162-8666 (Japan); Iwaki, M. [Beam Application Team, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Yamada, T. [Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162-8601 (Japan)

    2007-04-15

    In surgery, bleeding from small injured vessels often requires prompt hemostasis without occlusion. This study evaluated the usefulness of 0.06 mm thick ion beam irradiated ePTFE sheets to repair small holes in vessels. Both surfaces of ePTFE sheets were irradiated with a 150 keV-Ar{sup +} beam with fluences of 5 x 10{sup 14} ions/cm{sup 2}. A small hole up to 2 mm in diameter was created in the common carotid artery of a rabbit. The defect was wrapped with an ion beam irradiated or non-irradiated ePTFE sheet. Fibrin glue was used to fix the ePTFE sheets to the common carotid artery. Hemostasis was instantly obtained with ion beam irradiated ePTFE but was rather difficult when using a non-irradiated ePTFE sheet. Three weeks after implantation, no occlusion was observed. Histological examination showed that the ePTFE sheets functioned as a scaffold for vessel wall regeneration. Thin ion beam irradiated ePTFE would be useful in vascular surgery.

  3. Novel Method for Vessel Cross-Sectional Shear Wave Imaging.

    Science.gov (United States)

    He, Qiong; Li, Guo-Yang; Lee, Fu-Feng; Zhang, Qihao; Cao, Yanping; Luo, Jianwen

    2017-07-01

    Many studies have investigated the applications of shear wave imaging (SWI) to vascular elastography, mainly on the longitudinal section of vessels. It is important to investigate SWI in the arterial cross section when evaluating anisotropy of the vessel wall or complete plaque composition. Here, we proposed a novel method based on the coordinate transformation and directional filter in the polar coordinate system to achieve vessel cross-sectional shear wave imaging. In particular, ultrasound radiofrequency data were transformed from the Cartesian to the polar coordinate system; the radial displacements were then estimated directly. Directional filtering was performed along the circumferential direction to filter out the reflected waves. The feasibility of the proposed vessel cross-sectional shear wave imaging method was investigated through phantom experiments and ex vivo and in vivo studies. Our results indicated that the dispersion relation of the shear wave (i.e., the guided circumferential wave) within the vessel can be measured via the present method, and the elastic modulus of the vessel can be determined. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  4. Through-wall sampling of the Trawsfynydd RPV

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1996-06-01

    Four large, highly irradiated through-wall weld samples are to be removed from the Trawsfynydd Magnox reactor pressure vessel. The reactor was shut down in 1993 after 28 years of operation. The samples will be tested to investigate the integrity of steel pressure vessels. The choice of specialised tooling for the operation and its deployment are discussed. A Ultra High Power Pressure Water Jet cutting method has been selected to meet the demanding remote robotic requirements. (UK).

  5. Cells, walls, and endless forms.

    Science.gov (United States)

    Monniaux, Marie; Hay, Angela

    2016-12-01

    A key question in biology is how the endless diversity of forms found in nature evolved. Understanding the cellular basis of this diversity has been aided by advances in non-model experimental systems, quantitative image analysis tools, and modeling approaches. Recent work in plants highlights the importance of cell wall and cuticle modifications for the emergence of diverse forms and functions. For example, explosive seed dispersal in Cardamine hirsuta depends on the asymmetric localization of lignified cell wall thickenings in the fruit valve. Similarly, the iridescence of Hibiscus trionum petals relies on regular striations formed by cuticular folds. Moreover, NAC transcription factors regulate the differentiation of lignified xylem vessels but also the water-conducting cells of moss that lack a lignified secondary cell wall, pointing to the origin of vascular systems. Other novel forms are associated with modified cell growth patterns, including oriented cell expansion or division, found in the long petal spurs of Aquilegia flowers, and the Sarracenia purpurea pitcher leaf, respectively. Another good example is the regulation of dissected leaf shape in C. hirsuta via local growth repression, controlled by the REDUCED COMPLEXITY HD-ZIP class I transcription factor. These studies in non-model species often reveal as much about fundamental processes of development as they do about the evolution of form. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. The vessel fluence; Fluence cuve

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This book presents the proceedings of the technical meeting on the reactors vessels fluence. They are grouped in eight sessions: the industrial context and the stakes of the vessels control; the organization and the methodology for the fluence computation; the concerned physical properties; the reference computation methods; the fluence monitoring in an industrial context; vessels monitoring under irradiation; others methods in the world; the research and development programs. (A.L.B.)

  7. Preliminary investigation on the suitablity of using fiber reinforced concrete in the construction of a hazardous waste disposal vessel

    Energy Technology Data Exchange (ETDEWEB)

    Ramey, M.R.; Daie-e, G.

    1988-07-01

    There are certain hazardous wastes that must be contained in an extremely secure vessel for transportation and disposal. The vessel, among other things, must be able to withstand relatively large impacts without rupturing. Such containment vessels therefore must be able to absorb substantial amounts of energy during an impact and still perform their function. One of the impacts that the vessel must withstand is a 30-foot fall onto an unyielding surface. For some disposal scenarios it is proposed to encase the waste in a steel enclosure which is to be surrounded by a thick layer of concrete which, in turn, is encased by a relatively thin steel shell. Tests on concrete in compression and flexure, including static, dynamic and impact tests, have shown that low modulus concretes tend to behave in a less brittle manner than higher modulus concretes. Tests also show that fiber reinforced concretes have significantly greater ductility, crack propagation resistance and toughness than conventional concretes. Since it is known that concrete is a reasonably brittle material, it is necessary to do impact tests on sample containment structures consisting of thin-walled metal containers having closed ends which are filled with concrete, grout, or fiber reinforced concrete. This report presents the results of simple tests aimed at observing the behavior of sample containment structures subjected to impacts due to a fall from 30 feet. 8 figs., 4 tabs.

  8. Lipoxygenase mediates invasion of intrametastatic lymphatic vessels and propagates lymph node metastasis of human mammary carcinoma xenografts in mouse.

    Science.gov (United States)

    Kerjaschki, Dontscho; Bago-Horvath, Zsuzsanna; Rudas, Margaretha; Sexl, Veronika; Schneckenleithner, Christine; Wolbank, Susanne; Bartel, Gregor; Krieger, Sigurd; Kalt, Romana; Hantusch, Brigitte; Keller, Thomas; Nagy-Bojarszky, Katalin; Huttary, Nicole; Raab, Ingrid; Lackner, Karin; Krautgasser, Katharina; Schachner, Helga; Kaserer, Klaus; Rezar, Sandra; Madlener, Sybille; Vonach, Caroline; Davidovits, Agnes; Nosaka, Hitonari; Hämmerle, Monika; Viola, Katharina; Dolznig, Helmut; Schreiber, Martin; Nader, Alexander; Mikulits, Wolfgang; Gnant, Michael; Hirakawa, Satoshi; Detmar, Michael; Alitalo, Kari; Nijman, Sebastian; Offner, Felix; Maier, Thorsten J; Steinhilber, Dieter; Krupitza, Georg

    2011-05-01

    In individuals with mammary carcinoma, the most relevant prognostic predictor of distant organ metastasis and clinical outcome is the status of axillary lymph node metastasis. Metastases form initially in axillary sentinel lymph nodes and progress via connecting lymphatic vessels into postsentinel lymph nodes. However, the mechanisms of consecutive lymph node colonization are unknown. Through the analysis of human mammary carcinomas and their matching axillary lymph nodes, we show here that intrametastatic lymphatic vessels and bulk tumor cell invasion into these vessels highly correlate with formation of postsentinel metastasis. In an in vitro model of tumor bulk invasion, human mammary carcinoma cells caused circular defects in lymphatic endothelial monolayers. These circular defects were highly reminiscent of defects of the lymphovascular walls at sites of tumor invasion in vivo and were primarily generated by the tumor-derived arachidonic acid metabolite 12S-HETE following 15-lipoxygenase-1 (ALOX15) catalysis. Accordingly, pharmacological inhibition and shRNA knockdown of ALOX15 each repressed formation of circular defects in vitro. Importantly, ALOX15 knockdown antagonized formation of lymph node metastasis in xenografted tumors. Furthermore, expression of lipoxygenase in human sentinel lymph node metastases correlated inversely with metastasis-free survival. These results provide evidence that lipoxygenase serves as a mediator of tumor cell invasion into lymphatic vessels and formation of lymph node metastasis in ductal mammary carcinomas.

  9. Structural Health Monitoring of Composite Wound Pressure Vessels

    Science.gov (United States)

    Grant, Joseph; Kaul, Raj; Taylor, Scott; Jackson, Kurt; Myers, George; Sharma, A.

    2002-01-01

    The increasing use of advanced composite materials in the wide range of applications including Space Structures is a great impetus to the development of smart materials. Incorporating these FBG sensors for monitoring the integrity of structures during their life cycle will provide valuable information about viability of the usage of such material. The use of these sensors by surface bonding or embedding in this composite will measure internal strain and temperature, and hence the integrity of the assembled engineering structures. This paper focuses on such a structure, called a composite wound pressure vessel. This vessel was fabricated from the composite material: TRH50 (a Mitsubishi carbon fiber with a 710-ksi tensile strength and a 37 Msi modulus) impregnated with an epoxy resin from NEWPORT composites (WDE-3D-1). This epoxy resin in water dispersed system without any solvents and it cures in the 240-310 degrees F range. This is a toughened resin system specifically designed for pressure applications. These materials are a natural fit for fiber sensors since the polyimide outer buffer coating of fiber can be integrated into the polymer matrix of the composite material with negligible residual stress. The tank was wound with two helical patterns and 4 hoop wraps. The order of winding is: two hoops, two helical and two hoops. The wall thickness of the composite should be about 80 mil or less. The tank should burst near 3,000 psi or less. We can measure the actual wall thickness by ultrasonic or we can burst the tank and measure the pieces. Figure 1 shows a cylinder fabricated out of carbon-epoxy composite material. The strain in different directions is measured with a surface bonded fiber Bragg gratings and with embedded fiber Bragg gratings as the cylinder is pressurized to burst pressures. Figure 2 shows the strain as a function of pressure of carbon-epoxy cylinder as it is pressurized with water. Strain is measured in different directions by multiple gratings

  10. [Large vessel vasculitides].

    Science.gov (United States)

    Morović-Vergles, Jadranka; Puksić, Silva; Gracanin, Ana Gudelj

    2013-01-01

    Large vessel vasculitis includes Giant cell arteritis and Takayasu arteritis. Giant cell arteritis is the most common form of vasculitis affect patients aged 50 years or over. The diagnosis should be considered in older patients who present with new onset of headache, visual disturbance, polymyalgia rheumatica and/or fever unknown cause. Glucocorticoides remain the cornerstone of therapy. Takayasu arteritis is a chronic panarteritis of the aorta ant its major branches presenting commonly in young ages. Although all large arteries can be affected, the aorta, subclavian and carotid arteries are most commonly involved. The most common symptoms included upper extremity claudication, hypertension, pain over the carotid arteries (carotidynia), dizziness and visual disturbances. Early diagnosis and treatment has improved the outcome in patients with TA.

  11. Vessel segmentation in screening mammograms

    Science.gov (United States)

    Mordang, J. J.; Karssemeijer, N.

    2015-03-01

    Blood vessels are a major cause of false positives in computer aided detection systems for the detection of breast cancer. Therefore, the purpose of this study is to construct a framework for the segmentation of blood vessels in screening mammograms. The proposed framework is based on supervised learning using a cascade classifier. This cascade classifier consists of several stages where in each stage a GentleBoost classifier is trained on Haar-like features. A total of 30 cases were included in this study. In each image, vessel pixels were annotated by selecting pixels on the centerline of the vessel, control samples were taken by annotating a region without any visible vascular structures. This resulted in a total of 31,000 pixels marked as vascular and over 4 million control pixels. After training, the classifier assigns a vesselness likelihood to the pixels. The proposed framework was compared to three other vessel enhancing methods, i) a vesselness filter, ii) a gaussian derivative filter, and iii) a tubeness filter. The methods were compared in terms of area under the receiver operating characteristics curves, the Az values. The Az value of the cascade approach is 0:85. This is superior to the vesselness, Gaussian, and tubeness methods, with Az values of 0:77, 0:81, and 0:78, respectively. From these results, it can be concluded that our proposed framework is a promising method for the detection of vessels in screening mammograms.

  12. Americium behaviour in plastic vessels

    Energy Technology Data Exchange (ETDEWEB)

    Legarda, F.; Herranz, M. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Idoeta, R., E-mail: raquel.idoeta@ehu.e [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Abelairas, A. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain)

    2010-07-15

    The adsorption of {sup 241}Am dissolved in water in different plastic storage vessels was determined. Three different plastics were investigated with natural and distilled waters and the retention of {sup 241}Am by these plastics was studied. The same was done by varying vessel agitation time, vessel agitation speed, surface/volume ratio of water in the vessels and water pH. Adsorptions were measured to be between 0% and 70%. The adsorption of {sup 241}Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification.

  13. Simulation of the electromagnetic wall response to plasma wall-touching kink and vertical modes with application to ITER

    Science.gov (United States)

    Atanasiu, Calin; Zakharov, Leonid; Lackner, Karl; Hoelzl, Matthias; Strumberger, Erika

    2017-10-01

    Realistic simulations of electric current excitation in three-dimensional vessel structures by the plasma touching the walls are necessary to understand plasma disruptions in tokamak. In large tokamaks like ITER, the wall-touching kink modes cause large sideway forces on the vacuum vessel determined by the sharing of asymmetric electric current between the plasma and the wall. Our model covers both eddy currents, excited inductively by vertical modes, and source/sink currents due to current sharing between the plasma and the thin conducting wall. The developed finite element approach calculates the electromagnetic wall response to perturbation of magnetic fields and to current sharing between the plasma and the wall. The current density entering/exiting the wall surface from the plasma and the time derivative of the magnetic vector potential of the plasma are the input values. The magnetic field and the vector potential from the wall currents are returned as output. Our model has been checked against analytical examples of a multiply-connected domain of a real ITER wall.

  14. Reinforcement mechanism of multi-anchor wall with double wall facing

    Science.gov (United States)

    Suzuki, Kouta; Kobayashi, Makoto; Miura, Kinya; Konami, Takeharu; Hayashi, Taketo

    2017-10-01

    The reinforced soil wall has high seismic performance as generally known. However, the seismic behavior has not been clarified accurately yet, especially on multi-anchor wall with double wall facing. Indefinite behavior of reinforced soil wall during earthquake make us complicated in case with adopting to the abutment, because of arrangement of anchor plate as reinforcement often different according to the width of roads. In this study, a series of centrifuge model tests were carried out to investigate the reinforcement mechanism of multi anchor wall with double wall facing from the perspective of the vertical earth pressure. Several types of reinforce arrangement and rigid wall were applied in order to verify the arch function in the reinforced regions. The test results show unique behavior of vertical earth pressure, which was affected by arch action. All the vertical earth pressure placed behind facing panel, are larger than that of middle part between facing panel despite of friction between backfill and facing panel. Similar results were obtained in case using rigid wall. On the other hands, the vertical earth pressure, which were measured at the 3cm high from bottom of model container, shows larger than that of bottom. This results show the existence of arch action between double walls. In addition, it implies that the wall facing of such soil structure confined the backfill as pseudo wall, which is very reason that the multi anchor wall with double wall facing has high seismic performance.

  15. Lung vessel segmentation in CT images using graph-cuts

    Science.gov (United States)

    Zhai, Zhiwei; Staring, Marius; Stoel, Berend C.

    2016-03-01

    Accurate lung vessel segmentation is an important operation for lung CT analysis. Filters that are based on analyzing the eigenvalues of the Hessian matrix are popular for pulmonary vessel enhancement. However, due to their low response at vessel bifurcations and vessel boundaries, extracting lung vessels by thresholding the vesselness is not sufficiently accurate. Some methods turn to graph-cuts for more accurate segmentation, as it incorporates neighbourhood information. In this work, we propose a new graph-cuts cost function combining appearance and shape, where CT intensity represents appearance and vesselness from a Hessian-based filter represents shape. Due to the amount of voxels in high resolution CT scans, the memory requirement and time consumption for building a graph structure is very high. In order to make the graph representation computationally tractable, those voxels that are considered clearly background are removed from the graph nodes, using a threshold on the vesselness map. The graph structure is then established based on the remaining voxel nodes, source/sink nodes and the neighbourhood relationship of the remaining voxels. Vessels are segmented by minimizing the energy cost function with the graph-cuts optimization framework. We optimized the parameters used in the graph-cuts cost function and evaluated the proposed method with two manually labeled sub-volumes. For independent evaluation, we used 20 CT scans of the VESSEL12 challenge. The evaluation results of the sub-volume data show that the proposed method produced a more accurate vessel segmentation compared to the previous methods, with F1 score 0.76 and 0.69. In the VESSEL12 data-set, our method obtained a competitive performance with an area under the ROC curve of 0.975, especially among the binary submissions.

  16. Spontaneous Behaviors and Wall-Curvature Lead to Apparent Wall Preference in Planarian.

    Science.gov (United States)

    Akiyama, Yoshitaro; Agata, Kiyokazu; Inoue, Takeshi

    2015-01-01

    The planarian Dugesia japonica tends to stay near the walls of its breeding containers and experimental dishes in the laboratory, a phenomenon called "wall preference". This behavior is thought to be important for environmental adaptation, such as hiding by planarians in nature. However, the mechanisms regulating wall-preference behavior are not well understood, since this behavior occurs in the absence of any particular stimulation. Here we show the mechanisms of wall-preference behavior. Surprisingly, planarian wall-preference behavior was also shown even by the head alone and by headless planarians. These results indicate that planarian "wall-preference" behavior only appears to be a "preference" behavior, and is actually an outcome of spontaneous behaviors, rather than of brain function. We found that in the absence of environmental cues planarians moved basically straight ahead until they reached a wall, and that after reaching a wall, they changed their direction of movement to one tangential to the wall, suggesting that this spontaneous behavior may play a critical role in the wall preference. When we tested another spontaneous behavior, the wigwag movement of the planarian head, using computer simulation with various wigwag angles and wigwag intervals, large wigwag angle and short wigwag interval reduced wall-preference behavior. This indicated that wigwag movement may determine the probability of staying near the wall or leaving the wall. Furthermore, in accord with this simulation, when we tested planarian wall-preference behavior using several assay fields with different curvature of the wall, we found that concavity and sharp curvature of walls negatively impacted wall preference by affecting the permissible angle of the wigwag movement. Together, these results indicate that planarian wall preference may be involuntarily caused by the combination of two spontaneous planarian behaviors: moving straight ahead until reaching a wall and then moving along it

  17. Spontaneous Behaviors and Wall-Curvature Lead to Apparent Wall Preference in Planarian.

    Directory of Open Access Journals (Sweden)

    Yoshitaro Akiyama

    Full Text Available The planarian Dugesia japonica tends to stay near the walls of its breeding containers and experimental dishes in the laboratory, a phenomenon called "wall preference". This behavior is thought to be important for environmental adaptation, such as hiding by planarians in nature. However, the mechanisms regulating wall-preference behavior are not well understood, since this behavior occurs in the absence of any particular stimulation. Here we show the mechanisms of wall-preference behavior. Surprisingly, planarian wall-preference behavior was also shown even by the head alone and by headless planarians. These results indicate that planarian "wall-preference" behavior only appears to be a "preference" behavior, and is actually an outcome of spontaneous behaviors, rather than of brain function. We found that in the absence of environmental cues planarians moved basically straight ahead until they reached a wall, and that after reaching a wall, they changed their direction of movement to one tangential to the wall, suggesting that this spontaneous behavior may play a critical role in the wall preference. When we tested another spontaneous behavior, the wigwag movement of the planarian head, using computer simulation with various wigwag angles and wigwag intervals, large wigwag angle and short wigwag interval reduced wall-preference behavior. This indicated that wigwag movement may determine the probability of staying near the wall or leaving the wall. Furthermore, in accord with this simulation, when we tested planarian wall-preference behavior using several assay fields with different curvature of the wall, we found that concavity and sharp curvature of walls negatively impacted wall preference by affecting the permissible angle of the wigwag movement. Together, these results indicate that planarian wall preference may be involuntarily caused by the combination of two spontaneous planarian behaviors: moving straight ahead until reaching a wall and

  18. Numerical model study of radio frequency vessel sealing thermodynamics

    Science.gov (United States)

    Pearce, John

    2015-03-01

    Several clinically successful clinical radio frequency vessel-sealing devices are currently available. The dominant thermodynamic principles at work involve tissue water vaporization processes. It is necessary to thermally denature vessel collagen, elastin and their adherent proteins to achieve a successful fusion. Collagens denature at middle temperatures, between about 60 and 90 C depending on heating time and rate. Elastin, and its adherent proteins, are more thermally robust, and require temperatures in excess of the boiling point of water at atmospheric pressure to thermally fuse. Rapid boiling at low apposition pressures leads to steam vacuole formation, brittle tissue remnants and frequently to substantial disruption in the vessel wall, particularly in high elastin-content arteries. High apposition pressures substantially increase the equilibrium boiling point of tissue water and are necessary to ensure a high probability of a successful seal. The FDM numerical models illustrate the beneficial effects of high apposition pressures.

  19. Dynamic stroma reorganization drives blood vessel dysmorphia during glioma growth.

    Science.gov (United States)

    Mathivet, Thomas; Bouleti, Claire; Van Woensel, Matthias; Stanchi, Fabio; Verschuere, Tina; Phng, Li-Kun; Dejaegher, Joost; Balcer, Marly; Matsumoto, Ken; Georgieva, Petya B; Belmans, Jochen; Sciot, Raf; Stockmann, Christian; Mazzone, Massimiliano; De Vleeschouwer, Steven; Gerhardt, Holger

    2017-10-16

    Glioma growth and progression are characterized by abundant development of blood vessels that are highly aberrant and poorly functional, with detrimental consequences for drug delivery efficacy. The mechanisms driving this vessel dysmorphia during tumor progression are poorly understood. Using longitudinal intravital imaging in a mouse glioma model, we identify that dynamic sprouting and functional morphogenesis of a highly branched vessel network characterize the initial tumor growth, dramatically changing to vessel expansion, leakage, and loss of branching complexity in the later stages. This vascular phenotype transition was accompanied by recruitment of predominantly pro-inflammatory M1-like macrophages in the early stages, followed by in situ repolarization to M2-like macrophages, which produced VEGF-A and relocate to perivascular areas. A similar enrichment and perivascular accumulation of M2 versus M1 macrophages correlated with vessel dilation and malignancy in human glioma samples of different WHO malignancy grade. Targeting macrophages using anti-CSF1 treatment restored normal blood vessel patterning and function. Combination treatment with chemotherapy showed survival benefit, suggesting that targeting macrophages as the key driver of blood vessel dysmorphia in glioma progression presents opportunities to improve efficacy of chemotherapeutic agents. We propose that vessel dysfunction is not simply a general feature of tumor vessel formation, but rather an emergent property resulting from a dynamic and functional reorganization of the tumor stroma and its angiogenic influences. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

  20. Boosted learned kernels for data-driven vesselness measure

    Science.gov (United States)

    Grisan, E.

    2017-03-01

    Common vessel centerline extraction methods rely on the computation of a measure providing the likeness of the local appearance of the data to a curvilinear tube-like structure. The most popular techniques rely on empirically designed (hand crafted) measurements as the widely used Hessian vesselness, the recent oriented flux tubeness or filters (e.g. the Gaussian matched filter) that are developed to respond to local features, without exploiting any context information nor the rich structural information embedded in the data. At variance with the previously proposed methods, we propose a completely data-driven approach for learning a vesselness measure from expert-annotated dataset. For each data point (voxel or pixel), we extract the intensity values in a neighborhood region, and estimate the discriminative convolutional kernel yielding a positive response for vessel data and negative response for non-vessel data. The process is iterated within a boosting framework, providing a set of linear filters, whose combined response is the learned vesselness measure. We show the results of the general-use proposed method on the DRIVE retinal images dataset, comparing its performance against the hessian-based vesselness, oriented flux antisymmetry tubeness, and vesselness learned with a probabilistic boosting tree or with a regression tree. We demonstrate the superiority of our approach that yields a vessel detection accuracy of 0.95, with respect to 0.92 (hessian), 0.90 (oriented flux) and 0.85 (boosting tree).

  1. Proximal Bright Vessel Sign on Arterial Spin Labeling Magnetic Resonance Imaging in Acute Cardioembolic Cerebral Infarction.

    Science.gov (United States)

    Kato, Ayumi; Shinohara, Yuki; Kuya, Keita; Sakamoto, Makoto; Kowa, Hisanori; Ogawa, Toshihide

    2017-07-01

    The congestion of spin-labeled blood at large-vessel occlusion can present as hyperintense signals on perfusion magnetic resonance imaging with 3-dimensional pseudo-continuous arterial spin labeling (proximal bright vessel sign). The purpose of this study was to clarify the difference between proximal bright vessel sign and susceptibility vessel sign in acute cardioembolic cerebral infarction. Forty-two patients with cardioembolic cerebral infarction in the anterior circulation territory underwent magnetic resonance imaging including diffusion-weighted imaging, 3-dimensional pseudo-continuous arterial spin labeling perfusion magnetic resonance imaging, T2*-weighted imaging, and 3-dimensional time-of-flight magnetic resonance angiography using a 3-T magnetic resonance scanner. Visual assessments of proximal bright vessel sign and the susceptibility vessel sign were performed by consensus of 2 experienced neuroradiologists. The relationship between these signs and the occlusion site of magnetic resonance angiography was also investigated. Among 42 patients with cardioembolic cerebral infarction, 24 patients showed proximal bright vessel sign (57.1%) and 25 showed susceptibility vessel sign (59.5%). There were 19 cases of proximal bright vessel sign and susceptibility vessel sign-clear, 12 cases of proximal bright vessel sign and susceptibility vessel sign-unclear, and 11 mismatched cases. Four out of 6 patients with proximal bright vessel sign-unclear and susceptibility vessel sign-clear showed distal middle cerebral artery occlusion, and 2 out of 5 patients with proximal bright vessel sign-clear and susceptibility vessel sign-unclear showed no occlusion on magnetic resonance angiography. Proximal bright vessel sign is almost compatible with susceptibility vessel sign in patients with cardioembolic cerebral infarction. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  2. Infrared laser thermal fusion of blood vessels: preliminary ex vivo tissue studies

    Science.gov (United States)

    Cilip, Christopher M.; Rosenbury, Sarah B.; Giglio, Nicholas; Hutchens, Thomas C.; Schweinsberger, Gino R.; Kerr, Duane; Latimer, Cassandra; Nau, William H.; Fried, Nathaniel M.

    2013-05-01

    Suture ligation of blood vessels during surgery can be time-consuming and skill-intensive. Energy-based, electrosurgical, and ultrasonic devices have recently replaced the use of sutures and mechanical clips (which leave foreign objects in the body) for many surgical procedures, providing rapid hemostasis during surgery. However, these devices have the potential to create an undesirably large collateral zone of thermal damage and tissue necrosis. We explore an alternative energy-based technology, infrared lasers, for rapid and precise thermal coagulation and fusion of the blood vessel walls. Seven near-infrared lasers (808, 980, 1075, 1470, 1550, 1850 to 1880, and 1908 nm) were tested during preliminary tissue studies. Studies were performed using fresh porcine renal vessels, ex vivo, with native diameters of 1 to 6 mm, and vessel walls flattened to a total thickness of 0.4 mm. A linear beam profile was applied normal to the vessel for narrow, full-width thermal coagulation. The laser irradiation time was 5 s. Vessel burst pressure measurements were used to determine seal strength. The 1470 nm laser wavelength demonstrated the capability of sealing a wide range of blood vessels from 1 to 6 mm diameter with burst strengths of 578±154, 530±171, and 426±174 mmHg for small, medium, and large vessel diameters, respectively. Lateral thermal coagulation zones (including the seal) measured 1.0±0.4 mm on vessels sealed at this wavelength. Other laser wavelengths (1550, 1850 to 1880, and 1908 nm) were also capable of sealing vessels, but were limited by lower vessel seal pressures, excessive charring, and/or limited power output preventing treatment of large vessels (>4 mm outer diameter).

  3. Quantification of wall shear stress using a finite-element method in multidimensional phase-contrast MR data of the thoracic aorta.

    Science.gov (United States)

    Sotelo, Julio; Urbina, Jesús; Valverde, Israel; Tejos, Cristian; Irarrázaval, Pablo; Hurtado, Daniel E; Uribe, Sergio

    2015-07-16

    We present a computational method for calculating the distribution of wall shear stress (WSS) in the aorta based on a velocity field obtained from two-dimensional (2D) phase-contrast magnetic resonance imaging (PC-MRI) data and a finite-element method. The WSS vector was obtained from a global least-squares stress-projection method. The method was benchmarked against the Womersley model, and the robustness was assessed by changing resolution, noise, and positioning of the vessel wall. To showcase the applicability of the method, we report the axial, circumferential and magnitude of the WSS using in-vivo data from five volunteers. Our results showed that WSS values obtained with our method were in good agreement with those obtained from the Womersley model. The results for the WSS contour means showed a systematic but decreasing bias when the pixel size was reduced. The proposed method proved to be robust to changes in noise level, and an incorrect position of the vessel wall showed large errors when the pixel size was decreased. In volunteers, the results obtained were in good agreement with those found in the literature. In summary, we have proposed a novel image-based computational method for the estimation of WSS on vessel sections with arbitrary cross-section geometry that is robust in the presence of noise and boundary misplacements. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Mice Lacking Endoglin in Macrophages Show an Impaired Immune Response.

    Directory of Open Access Journals (Sweden)

    Luisa Ojeda-Fernández

    2016-03-01

    Full Text Available Endoglin is an auxiliary receptor for members of the TGF-β superfamily and plays an important role in the homeostasis of the vessel wall. Mutations in endoglin gene (ENG or in the closely related TGF-β receptor type I ACVRL1/ALK1 are responsible for a rare dominant vascular dysplasia, the Hereditary Hemorrhagic Telangiectasia (HHT, or Rendu-Osler-Weber syndrome. Endoglin is also expressed in human macrophages, but its role in macrophage function remains unknown. In this work, we show that endoglin expression is triggered during the monocyte-macrophage differentiation process, both in vitro and during the in vivo differentiation of blood monocytes recruited to foci of inflammation in wild-type C57BL/6 mice. To analyze the role of endoglin in macrophages in vivo, an endoglin myeloid lineage specific knock-out mouse line (Eng(fl/flLysMCre was generated. These mice show a predisposition to develop spontaneous infections by opportunistic bacteria. Eng(fl/flLysMCre mice also display increased survival following LPS-induced peritonitis, suggesting a delayed immune response. Phagocytic activity is impaired in peritoneal macrophages, altering one of the main functions of macrophages which contributes to the initiation of the immune response. We also observed altered expression of TGF-β1 target genes in endoglin deficient peritoneal macrophages. Overall, the altered immune activity of endoglin deficient macrophages could help to explain the higher rate of infectious diseases seen in HHT1 patients.

  5. The extended abdominal wall flap for transplantation.

    Science.gov (United States)

    Hollenbeck, S T; Senghaas, A; Turley, R; Ravindra, K V; Zenn, M R; Levin, L S; Erdmann, D

    2011-06-01

    Patients with extensive loss of the abdominal wall tissue have few options for restoring the abdominal cavity. Composite tissue allotransplantation has been used for limited abdominal wall reconstruction in the setting of visceral transplantation, yet replacement of the entire abdominal wall has not been described. The purpose of this study was to determine the maximal abdominal skin surface available through an external iliac/femoral cuff-based pedicle. Five human cadaveric abdominal walls were injected with methylene blue to analyze skin perfusion based on either the deep inferior epigastric artery (DIEA; n = 5) or a cuff of external iliac/femoral artery (n = 5) containing the deep circumflex iliac, deep inferior epigastric, and superficial inferior epigastric, and superficial circumflex iliac arteries. Abdominal wall flaps were taken full thickness from the costal margin to the midaxillary line and down to the pubic tubercle and proximal thigh. In all specimens, the deep inferior epigastric, deep circumflex iliac, superficial inferior epigastric, and superficial circumflex iliac arteries were found to originate within a 4-cm cuff of the external iliac/femoral artery. Abdominal wall flaps injected through a unilateral external iliac/femoral segment had a significantly greater degree of total flap perfusion than those injected through the DIEA alone (76.5% ± 4% vs 57.2% ± 5%; Student t test, P DIEA vessel alone. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Endoplasmic reticulum stress inhibition reduces hypertension through the preservation of resistance blood vessel structure and function.

    Science.gov (United States)

    Carlisle, Rachel E; Werner, Kaitlyn E; Yum, Victoria; Lu, Chao; Tat, Victor; Memon, Muzammil; No, Yejin; Ask, Kjetil; Dickhout, Jeffrey G

    2016-08-01

    Our purpose was to determine if endoplasmic reticulum stress inhibition lowers blood pressure (BP) in hypertension by correcting vascular dysfunction. The spontaneously hypertensive rat (SHR) was used as a model of human essential hypertension with its normotensive control, the Wistar Kyoto rat. Animals were subjected to endoplasmic reticulum stress inhibition with 4-phenylbutyric acid (4-PBA; 1 g/kg per day, orally) for 5 weeks from 12 weeks of age. BP was measured weekly noninvasively and at endpoint with carotid arterial cannulation. Small mesenteric arteries were removed for vascular studies. Function was assessed with a Mulvany-Halpern style myograph, and structure was assessed by measurement of medial-to-lumen ratio in perfusion fixed vessels as well as three-dimensional confocal reconstruction of vessel wall components. Endoplasmic reticulum stress was assessed by quantitative real time-PCR and western blotting; oxidative stress was assessed by 3-nitrotyrosine and dihydroethidium staining. 4-PBA significantly lowered BP in SHR (vehicle 206.1 ± 4.3 vs. 4-PBA 178.9 ± 3.1, systolic) but not Wistar Kyoto. 4-PBA diminished contractility and augmented endothelial-dependent vasodilation in SHR small mesenteric arteries, as well as reducing media-to-lumen ratio. 4-PBA significantly reduced endoplasmic reticulum stress in SHR resistance vessels. Normotensive resistance vessels, treated with the endoplasmic reticulum stress-inducing agent, tunicamycin, show decreased endothelial-dependent vasodilation; this was improved with 4-PBA treatment. 3-Nitrotyrosine and dihydroethidium staining indicated that endoplasmic reticulum stress leads to reactive oxygen species generation resolvable by 4-PBA treatment. Endoplasmic reticulum stress caused endothelial-mediated vascular dysfunction contributing to elevated BP in the SHR model of human essential hypertension.

  7. Novel Method to Detect Corneal Lymphatic Vessels In Vivo by Intrastromal Injection of Fluorescein.

    Science.gov (United States)

    Le, Viet Nhat Hung; Hou, Yanhong; Horstmann, Jens; Bock, Felix; Cursiefen, Claus

    2017-11-09

    Corneal lymphatic vessels are clinically invisible because of their thin walls and clear lymph fluid. There is no easy and established method for in vivo imaging of corneal lymphatic vessels so far. In this study, we present a novel approach to visualize corneal lymphatic vessels in vivo by injecting intrastromal fluorescein sodium. Six- to eight-week-old female BALB/c mice were used in the mouse model of suture-induced corneal neovascularization. Two weeks after the suture placement, fluorescein sodium was injected intrastromally. The fluorescein, taken up by the presumed lymphatic vessels, was then tracked using a clinically used Spectralis HRA + OCT device. Immunohistochemistry staining with specific lymphatic marker LYVE-1 and pan-endothelial marker CD31 was used to confirm the indirect lymphangiography findings. By injecting fluorescein intrastromally, both corneal blood and lymphatic vessels were detected. While the lymphatic vessels were visible as bright vessel-like structures using HRA, the blood vessels appeared as dark networks. Fluorescein-labeled lymphatic vessels were colocalized with LYVE-1 in immunohistochemically stained sections of the same specimen. Corneal lymphatic vessels can be easily imaged in vivo in the murine model using intrastromal fluorescein injection.

  8. Fast blood-flow simulation for large arterial trees containing thousands of vessels.

    Science.gov (United States)

    Muller, Alexandre; Clarke, Richard; Ho, Harvey

    2017-02-01

    Blood flow modelling has previously been successfully carried out in arterial trees to study pulse wave propagation using nonlinear or linear flow solvers. However, the number of vessels used in the simulations seldom grows over a few hundred. The aim of this work is to present a computationally efficient solver coupled with highly detailed arterial trees containing thousands of vessels. The core of the solver is based on a modified transmission line method, which exploits the analogy between electrical current in finite-length conductors and blood flow in vessels. The viscoelastic behaviour of the arterial-wall is taken into account using a complex elastic modulus. The flow is solved vessel by vessel in the frequency domain and the calculated output pressure is then used as an input boundary condition for daughter vessels. The computational results yield pulsatile blood pressure and flow rate for every segment in the tree. This solver is coupled with large arterial trees generated from a three-dimensional constrained constructive optimisation algorithm. The tree contains thousands of blood vessels with radii spanning ~1 mm in the root artery to ~30 μm in leaf vessels. The computation takes seconds to complete for a vasculature of 2048 vessels and less than 2 min for a vasculature of 4096 vessels on a desktop computer.

  9. Characterization of xylan in the early stages of secondary cell wall formation in tobacco bright yellow-2 cells.

    Science.gov (United States)

    Ishii, Tadashi; Matsuoka, Keita; Ono, Hiroshi; Ohnishi-Kameyama, Mayumi; Yaoi, Katsuro; Nakano, Yoshimi; Ohtani, Misato; Demura, Taku; Iwai, Hiroaki; Satoh, Shinobu

    2017-11-15

    The major polysaccharides present in the primary and secondary walls surrounding plant cells have been well characterized. However, our knowledge of the early stages of secondary wall formation is limited. To address this, cell walls were isolated from differentiating xylem vessel elements of tobacco bright yellow-2 (BY-2) cells induced by VASCULAR-RELATED NAC-DOMAIN7 (VND7). The walls of induced VND7-VP16-GR BY-2 cells consisted of cellulose, pectic polysaccharides, hemicelluloses, and lignin, and contained more xylan and cellulose compared with non-transformed BY-2 and uninduced VND7-VP16-GR BY-2 cells. A reducing end sequence of xylan containing rhamnose and galaturonic acid- residues is present in the walls of induced, uninduced, and non-transformed BY-2 cells. Glucuronic acid residues in xylan from walls of induced cells are O-methylated, while those of xylan in non-transformed BY-2 and uninduced cells are not. Our results show that xylan changes in chemical structure and amounts during the early stages of xylem differentiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. 50 CFR 648.8 - Vessel identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Vessel identification. 648.8 Section 648.8... identification. (a) Vessel name and official number. Each fishing vessel subject to this part and over 25 ft (7.6... or ocean quahog vessels licensed under New Jersey law may use the appropriate vessel identification...

  11. 33 CFR 96.370 - What are the requirements for vessels of countries not party to Chapter IX of SOLAS?

    Science.gov (United States)

    2010-07-01

    ... OPERATION OF VESSELS AND SAFETY MANAGEMENT SYSTEMS How Will Safety Management Systems Be Certificated and...) Each foreign vessel which carries more than 12 passengers, or is a tanker, bulk freight vessel, freight... documentation showing that the vessel's company has a safety management system which was audited and assessed...

  12. Scanning electron microscopy of the dorsal vessel of Panstrongylus megistus (Burmeister, 1835 (Hemiptera: Reduviidae

    Directory of Open Access Journals (Sweden)

    Nadir Francisca Sant'Anna Nogueira

    1991-03-01

    Full Text Available In this study we analyzed the microanatomy of the dorsal vessel of the triatomine Panstrongylus megistus. The organ is a tuble anatomically divided into an anterior aorta anad a posterior heart, connected to the body wall through 8 pairs of alary muscles. The heart is divided in 3 chambers by means of 2 pairs of cardiac valves. a pair of ostia can be observed in the lateral wall of each chamber. A bundle of nerve fibers was found outside the organ, running dorsally along its major axis. A group of longitudinal muscular fibers was found in the ventral portion of the vessel. The vessel was found to be lined both internally and externally by pericardial cells covered by a thin laminar membrane. Inseide the vessel the pericardial cells were disposed in layers and on the outside they formed clusters or rows.

  13. An automated method for accurate vessel segmentation

    Science.gov (United States)

    Yang, Xin; Liu, Chaoyue; Le Minh, Hung; Wang, Zhiwei; Chien, Aichi; (Tim Cheng, Kwang-Ting

    2017-05-01

    Vessel segmentation is a critical task for various medical applications, such as diagnosis assistance of diabetic retinopathy, quantification of cerebral aneurysm’s growth, and guiding surgery in neurosurgical procedures. Despite technology advances in image segmentation, existing methods still suffer from low accuracy for vessel segmentation in the two challenging while common scenarios in clinical usage: (1) regions with a low signal-to-noise-ratio (SNR), and (2) at vessel boundaries disturbed by adjacent non-vessel pixels. In this paper, we present an automated system which can achieve highly accurate vessel segmentation for both 2D and 3D images even under these challenging scenarios. Three key contributions achieved by our system are: (1) a progressive contrast enhancement method to adaptively enhance contrast of challenging pixels that were otherwise indistinguishable, (2) a boundary refinement method to effectively improve segmentation accuracy at vessel borders based on Canny edge detection, and (3) a content-aware region-of-interests (ROI) adjustment method to automatically determine the locations and sizes of ROIs which contain ambiguous pixels and demand further verification. Extensive evaluation of our method is conducted on both 2D and 3D datasets. On a public 2D retinal dataset (named DRIVE (Staal 2004 IEEE Trans. Med. Imaging 23 501-9)) and our 2D clinical cerebral dataset, our approach achieves superior performance to the state-of-the-art methods including a vesselness based method (Frangi 1998 Int. Conf. on Medical Image Computing and Computer-Assisted Intervention) and an optimally oriented flux (OOF) based method (Law and Chung 2008 European Conf. on Computer Vision). An evaluation on 11 clinical 3D CTA cerebral datasets shows that our method can achieve 94% average accuracy with respect to the manual segmentation reference, which is 23% to 33% better than the five baseline methods (Yushkevich 2006 Neuroimage 31 1116-28; Law and Chung 2008

  14. Liver vessel segmentation and identification based on oriented flux symmetry and graph cuts.

    Science.gov (United States)

    Zeng, Ye-Zhan; Zhao, Yu-Qian; Tang, Ping; Liao, Miao; Liang, Yi-Xiong; Liao, Sheng-Hui; Zou, Bei-Ji

    2017-10-01

    Accurate segmentation of liver vessels from abdominal computer tomography angiography (CTA) volume is very important for liver-vessel analysis and living-related liver transplants. This paper presents a novel liver-vessel segmentation and identification method. Firstly, an anisotropic diffusion filter is used to smooth noise while preserving vessel boundaries. Then, based on the gradient symmetry and antisymmetry pattern of vessel structures, optimal oriented flux (OOF) and oriented flux antisymmetry (OFA) measures are respectively applied to detect liver vessels and their boundaries, and further to slenderize vessels. Next, according to vessel geometrical structure, a centerline extraction measure based on height ridge traversal and leaf node line-growing (LNLG) is proposed for the extraction of liver-vessel centerlines, and an intensity model based on fast marching is integrated into graph cuts (GCs) for effective segmentation of liver vessels. Finally, a distance voting mechanism is applied to separate the hepatic vein and portal vein. The experiment results on abdominal CTA images show that the proposed method can effectively segment liver vessels, achieving an average accuracy, sensitivity, and specificity of 97.7%, 79.8%, and 98.6%, respectively, and has a good performance on thin-vessel extraction. The proposed method does not require manual selection of the centerlines and vessel seeds, and can effectively segment liver vessels and identify hepatic vein and portal vein. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Noninvasive detection of coronary artery wall thickening with age in healthy subjects using high resolution MRI with beat-to-beat respiratory motion correction.

    Science.gov (United States)

    Scott, Andrew D; Keegan, Jennifer; Mohiaddin, Raad H; Firmin, David N

    2011-10-01

    To demonstrate coronary artery wall thickening with age in a small healthy cohort using a highly efficient, reliable, and reproducible high-resolution MR technique. A 3D cross-sectional MR vessel wall images (0.7 × 0.7 × 3 mm resolution) with retrospective beat-to-beat respiratory motion correction (B2B-RMC) were obtained in the proximal right coronary artery of 21 healthy subjects (age, 22-62 years) with no known cardiovascular disease. Lumen and outer wall (lumen + vessel wall) areas were measured in one central slice from each subject and average wall thickness and wall area/outer wall area ratio (W/OW) calculated. Imaging was successful in 18 (86%) subjects with average respiratory efficiency 99.3 ± 1.7%. Coronary vessel wall thickness and W/OW significantly correlate with subject age, increasing by 0.088 mm and 0.031 per decade respectively (R = 0.53, P = 0.024 and R = 0.48, P = 0.046). No relationship was found between lumen area and vessel wall thickness (P = NS), but outer wall area increased significantly with vessel wall thickness at 19 mm(2) per mm (P = 0.046). This is consistent with outward vessel wall remodeling. Despite the small size of our healthy cohort, using high-resolution MR imaging and B2B-RMC, we have demonstrated increasing coronary vessel wall thickness and W/OW with age. The results obtained are consistent with outward vessel wall remodeling. Copyright © 2011 Wiley-Liss, Inc.

  16. Bio-mathematical analysis for the peristaltic flow of single wall carbon nanotubes under the impact of variable viscosity and wall properties.

    Science.gov (United States)

    Shahzadi, Iqra; Sadaf, Hina; Nadeem, Sohail; Saleem, Anber

    2017-02-01

    The main objective of this paper is to study the Bio-mathematical analysis for the peristaltic flow of single wall carbon nanotubes under the impact of variable viscosity and wall properties. The right and the left walls of the curved channel possess sinusoidal wave that is travelling along the outer boundary. The features of the peristaltic motion are determined by using long wavelength and low Reynolds number approximation. Exact solutions are determined for the axial velocity and for the temperature profile. Graphical results have been presented for velocity profile, temperature and stream function for various physical parameters of interest. Symmetry of the curved channel is disturbed for smaller values of the curvature parameter. It is found that the altitude of the velocity profile increases for larger values of variable viscosity parameter for both the cases (pure blood as well as single wall carbon nanotubes). It is detected that velocity profile increases with increasing values of rigidity parameter. It is due to the fact that an increase in rigidity parameter decreases tension in the walls of the blood vessels which speeds up the blood flow for pure blood as well as single wall carbon nanotubes. Increase in Grashof number decreases the fluid velocity. This is due to the reason that viscous forces play a prominent role that's why increase in Grashof number decreases the velocity profile. It is also found that temperature drops for increasing values of nanoparticle volume fraction. Basically, higher thermal conductivity of the nanoparticles plays a key role for quick heat dissipation, and this justifies the use of the single wall carbon nanotubes in different situations as a coolant. Exact solutions are calculated for the temperature and the velocity profile. Symmetry of the curved channel is destroyed due to the curvedness for velocity, temperature and contour plots. Addition of single wall carbon nanotubes shows a decrease in fluid temperature. Trapping

  17. BY FRUSTUM CONFINING VESSEL

    Directory of Open Access Journals (Sweden)

    Javad Khazaei

    2016-09-01

    Full Text Available Helical piles are environmentally friendly and economical deep foundations that, due to environmental considerations, are excellent additions to a variety of deep foundation alternatives available to the practitioner. Helical piles performance depends on soil properties, the pile geometry and soil-pile interaction. Helical piles can be a proper alternative in sensitive environmental sites if their bearing capacity is sufficient to support applied loads. The failure capacity of helical piles in this study was measured via an experimental research program that was carried out by Frustum Confining Vessel (FCV. FCV is a frustum chamber by approximately linear increase in vertical and lateral stresses along depth from top to bottom. Due to special geometry and applied bottom pressure, this apparatus is a proper choice to test small model piles which can simulate field stress conditions. Small scale helical piles are made with either single helix or more helixes and installed in fine grained sand with three various densities. Axial loading tests including compression and tension tests were performed to achieve pile ultimate capacity. The results indicate the helical piles behavior depends essentially on pile geometric characteristics, i.e. helix configuration and soil properties. According to the achievements, axial uplift capacity of helical model piles is about equal to usual steel model piles that have the helixes diameter. Helical pile compression bearing capacity is too sufficient to act as a medium pile, thus it can be substituted other piles in special geoenvironmental conditions. The bearing capacity also depends on spacing ratio, S/D, and helixes diameter.

  18. Southeast Region Headboat Survey-Vessel list/Vessel Directory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a database of vessels that have been on the SRHS through time, their owners/operators, marinas/docks and their contact information. This assists in...

  19. [Vascularization of the wall of the superficial veins. Anatomic study of the vasa vasorum].

    Science.gov (United States)

    Lefebvre, D; Lescalie, F

    1996-01-01

    The blood vessel wall is almost always nourished by two ways; from the blood stream itself and through the outer part of the wall by vasa vasorum. The aim of this study was to demonstrate that this kind of nutrition is also available for the venous wall and to define the distribution pattern in superficial venous walls. 50 long saphenous veins and 20 short saphenous veins latex or barium injections, dissections with magnifying glasses and microradiographies. Topographical evaluation of the origin of vasa vasorum. The results showed that vasa vasorum originated from perforating arteries coming from several levels and getting a lot of anastomosis. We showed that the main sources for the long saphenous vein are the external pudendal artery and descending artery of the knee and for the short saphenous vein, the short saphenous vein artery. In thrombosis and varicose veins, the vasa were strongly altered. This study outlines the fact that superficial veins are supplied by arterial and venous vasa vasorum, and the role of vasa vasorum must be considered when questioning the pathogenesis of varicose and post thrombotic disease.

  20. Native vascular related NAC transcription factors are efficient regulator of multiple classes of secondary wall associated genes in banana.

    Science.gov (United States)

    Negi, Sanjana; Tak, Himanshu; Ganapathi, T R

    2017-12-01

    Secondary-wall deposition in xylem vessel elements is regulated by vascular-related NAC transcription factors (VNDs). We show that three banana VNDs (MusaVND1, MusaVND2 and MusaVND3) directly regulate multiple secondary-wall associated genes by binding to their 5'-upstream regulatory region. Transgenic banana harboring either P MusaVND1 :GUS, P MusaVND2 :GUS or P MusaVND3 :GUS showed specific GUS staining in lignified tissues. MusaVND1, MusaVND2 and MusaVND3 encodes transcriptional-activators as its C-terminal region drive expression of reporter genes in vivo in yeast. Purified MusaVND1, MusaVND2 and MusaVND3 proteins in gel shift assay bind to 19-bp secondary-wall NAC binding element (SNBE) while it fails to bind mutated SNBE. Putative SNBE sites in the 5'-upstream regulatory region of important secondary-wall associated genes related to programmed cell death (XCP1), cell-wall modification (IRX1/CesA8, IRX3/CesA7,IRX5/CesA4, IRX8, IRX10 and IRX12) and transcriptional regulation (MYB52, MYB48/59, MYB85, MYB58/72, MYB46, and MYB83) in banana was identified and mobility of these regulatory regions got retarded by MusaVND1, MusaVND2 and MusaVND3. Transcript level of these important secondary wall associated genes were elevated in transgenic banana overexpressing either MusaVND1, MusaVND2 or MusaVND3. Present study suggested promoters with prospective utilization in wall modification in banana (a potential biofuel crop) and suggest a complex transcriptional regulation of secondary wall deposition in plants. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Charged Domain Walls

    OpenAIRE

    Campanelli, L.; Cea, P.; Fogli, G. L.; Tedesco, L.

    2003-01-01

    In this paper we investigate Charged Domain Walls (CDW's), topological defects that acquire surface charge density $Q$ induced by fermion states localized on the walls. The presence of an electric and magnetic field on the walls is also discussed. We find a relation in which the value of the surface charge density $Q$ is connected with the existence of such topological defects.

  2. Collaborative investigations of in-service irradiated material from the Japan Power Demonstration Reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Corwin, W.R.; Broadhead, B.L. [Oak Ridge National Lab., TN (United States); Suzuki, M.; Kohsaka, A. [Japan Atomic Energy Research Institute, Tokai (Japan)

    1997-02-01

    There is a need to validate the results of irradiation effects research by the examination of material taken directly from the wall of a pressure vessel that has been irradiated during normal service. Just such an evaluation is currently being conducted on material from the wall of the pressure vessel from the Japan Power Demonstration Reactor (JPDR). The research is being jointly performed at the Tokai Research Establishment of the Japan Atomic Energy Research Institute (JAERI) and by the Nuclear Regulatory Commission (NRC)-funded Heavy-Section Steel Irradiation Program at the Oak Ridge National Laboratory (ORNL).

  3. Wall conditioning and particle control in Extrap T2

    Science.gov (United States)

    Bergsåker, H.; Larsson, D.; Brunsell, P.; Möller, A.; Tramontin, L.

    1997-02-01

    The Extrap T2 reversed field pinch experiment is operated with the former OHTE vacuum vessel, of dimensions R = 1.24 m and a = 0.18 m and with a complete graphite liner. It is shown that a rudimentary density control can be achieved by means of frequent helium glow discharge conditioning of the wall. The standard He-GDC is well characterized and reproducible. The trapping and release of hydrogen and impurities at the wall surfaces have been studied by mass spectrometry and surface analysis. The shot to shot particle exchange between wall and plasma can be approximately accounted for.

  4. Feeling Wall Tension in an Interactive Demonstration of Laplace's Law

    Science.gov (United States)

    Letic, Milorad

    2012-01-01

    Laplace's Law plays a major role in explanations of the wall tension of structures like blood vessels, the bladder, the uterus in pregnancy, bronchioles, eyeballs, and the behavior of aneurisms or the enlarged heart. The general relation of Laplace's law, expressing that the product of the radius of curvature (r) and pressure (P) is equal to wall…

  5. Vessel-guided airway tree segmentation

    DEFF Research Database (Denmark)

    Lo, Pechin Chien Pau; Sporring, Jon; Ashraf, Haseem

    2010-01-01

    method is evaluated on 250 low dose computed tomography images from a lung cancer screening trial. Our experiments showed that applying the region growing algorithm on the airway appearance model produces more complete airway segmentations, leading to on average 20% longer trees, and 50% less leakage......This paper presents a method for airway tree segmentation that uses a combination of a trained airway appearance model, vessel and airway orientation information, and region growing. We propose a voxel classification approach for the appearance model, which uses a classifier that is trained...... to differentiate between airway and non-airway voxels. This is in contrast to previous works that use either intensity alone or hand crafted models of airway appearance. We show that the appearance model can be trained with a set of easily acquired, incomplete, airway tree segmentations. A vessel orientation...

  6. Reactor Pressure Vessel (RPV) Acquisition Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Mizia, Ronald Eugene [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2008-04-01

    The Department of Energy has selected the High Temperature Gas-cooled Reactor design for the Next Generation Nuclear Plant (NGNP) Project. The NGNP will demonstrate the use of nuclear power for electricity and hydrogen production. It will have an outlet gas temperature in the range of 900°C and a plant design service life of 60 years. The reactor design will be a graphite moderated, helium-cooled, prismatic or pebble-bed reactor and use low-enriched uranium, TRISO-coated fuel. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during accidents. The NGNP Materials Research and Development (R&D) Program is responsible for performing R&D on likely NGNP materials in support of the NGNP design, licensing, and construction activities. Selection of the technology and design configuration for the NGNP must consider both the cost and risk profiles to ensure that the demonstration plant establishes a sound foundation for future commercial deployments. The NGNP challenge is to achieve a significant advancement in nuclear technology while at the same time setting the stage for an economically viable deployment of the new technology in the commercial sector soon after 2020. The purpose of this report is to address the acquisition strategy for the NGNP Reactor Pressure Vessel (RPV). This component will be larger than any nuclear reactor pressure vessel presently in service in the United States. The RPV will be taller, larger in diameter, thicker walled, heavier and most likely fabricated at the Idaho National Laboratory (INL) site of multiple subcomponent pieces. The pressure vessel steel can either be a conventional materials already used in the nuclear industry such as listed within ASME A508/A533 specifications or it will be fabricated from newer pressure vessel materials never before used for a nuclear reactor in the US. Each of these characteristics will present a

  7. 2013 East Coast Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  8. SC/OQ Vessel Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data tables holding information for the Surf Clam/Ocean Quahog vessel and dealer/processor logbooks (negative and positive), as well as individual tag information...

  9. 2011 Great Lakes Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  10. 2011 West Coast Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  11. 2013 Great Lakes Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  12. 2011 East Coast Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  13. Integrin binding: Sticking around vessels

    Science.gov (United States)

    Blatchley, Michael R.; Gerecht, Sharon

    2017-09-01

    A study demonstrates that controlled integrin binding on a biomaterial was capable of promoting vascular cell sprouting and formation of a non-leaky blood vessel network in a healthy and diseased state.

  14. Transposition of the great vessels

    Science.gov (United States)

    ... vessel called the ductus arteriosus open, allowing some mixing of the 2 blood circulations. A procedure using ... they are not already immune. Eating well, avoiding alcohol, and controlling diabetes both before and during pregnancy ...

  15. 2013 West Coast Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  16. Vessel Permit System Data Set

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GARFO issues federal fishing permits annually to owners of fishing vessels who fish in the Greater Atlantic region, as required by federal regulation. These permits...

  17. 2011 Tug Towing Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  18. Caribbean PR Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains catch (landed catch) and effort for fishing trips made by vessels fishing in Puerto Rico. The catch and effort data for the entire trip are...

  19. Coastal Discard Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains data on the type and amount of marine resources that are discarded or interacted with by vessels that are selected to report to the Southeast...

  20. Transmission electron microscopy, fluorescence microscopy, and confocal raman microscopic analysis of ultrastructural and compositional heterogeneity of Cornus alba L. wood cell wall.

    Science.gov (United States)

    Ma, Jianfeng; Ji, Zhe; Zhou, Xia; Zhang, Zhiheng; Xu, Feng

    2013-02-01

    Transmission electron microscopy (TEM), fluorescence microscopy, and confocal Raman microscopy can be used to characterize ultrastructural and compositional heterogeneity of plant cell walls. In this study, TEM observations revealed the ultrastructural characterization of Cornus alba L. fiber, vessel, axial parenchyma, ray parenchyma, and pit membrane between cells, notably with the ray parenchyma consisting of two well-defined layers. Fluorescence microscopy evidenced that cell corner middle lamella was more lignified than adjacent compound middle lamella and secondary wall with variation in lignification level from cell to cell. In situ Raman images showed that the inhomogeneity in cell wall components (cellulose and lignin) among different cells and within morphologically distinct cell wall layers. As the significant precursors of lignin biosynthesis, the pattern of coniferyl alcohol and aldehyde (joint abbreviation Lignin-CAA for both structures) distribution in fiber cell wall was also identified by Raman images, with higher concentration occurring in the fiber secondary wall where there was the highest cellulose concentration. Moreover, noteworthy was the observation that higher concentration of lignin and very minor amounts of cellulose were visualized in the pit membrane areas. These complementary microanalytical methods provide more accurate and complete information with regard to ultrastructural and compositional characterization of plant cell walls.

  1. Modeling the microclimate inside a vessel in in vitro culture : vessel ...

    African Journals Online (AJOL)

    M

    Numerical simulations show that variations in vessel internal humidity was ... Keywords : Agar, in vitro culture, microclimate, modeling, transfer coefficient. ... determining the atmospheric conditions inside .... is a function of air speed was used. .... latent heat of evaporation, R the gas constant and .... mesoscale circulation.

  2. Modeling corium jet breakup in water pool and application to ex-vessel fuel–coolant interaction analyses

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Kwang-Hyun, E-mail: khbang@hhu.ac.kr; Kumar, Rohit; Kim, Hyoung-Tak

    2014-09-15

    Highlights: • Kelvin–Helmholtz Instability on melt–steam–water interfaces was solved numerically. • Corium jet breakup model was developed for FCI codes based on the KHI solutions. • Ex-vessel steam explosions in reactor cavity were calculated using TRACER-II code. - Abstract: In light water reactor core melt accidents, the molten fuel can be brought into contact with coolant water in the course of the melt relocation in-vessel and ex-vessel as well as in an accident mitigation action of water addition. For the last several decades, the potential risk of energetic molten fuel coolant interactions (FCIs, steam explosions) has drawn substantial attention in the safety analysis of reactor severe accidents. In this paper, an improved melt jet breakup model is presented and analyses of an energetic fuel–coolant interaction in a PWR cavity (1) partially filled (4 m deep) and (2) completely filled (7 m deep) with water are presented. The TRACER-II code was used in the analyses. For jet breakup model, the full dispersion equation of Kelvin–Helmholtz instability for the melt jet–vapor film–water was solved numerically and the solutions were correlated for use in the TRACER-II code. The new jet breakup model was benchmarked using FARO L28 test data. In reactor calculations the mixing calculations showed that the average melt drop size was much smaller in 4 m deep pool with 3 m free-fall than in 7 m deep pool. The explosion calculations showed that the peak pressure at the center of mixture was ∼90 MPa in 4 m deep pool, ∼25 MPa in 7 m deep pool. It also showed that the maximum impulse at the cavity wall was found at the lower wall in both cases and it was 50 kPa s in 4 m deep pool and 150 kPa s in 7 m deep pool.

  3. Multiscale Vessel-guided Airway Tree Segmentation

    DEFF Research Database (Denmark)

    Lo, Pechin Chien Pau; Sporring, Jon; de Bruijne, Marleen

    2009-01-01

    This paper presents a method for airway tree segmentation that uses a combination of a trained airway appearance model, vessel and airway orientation information, and region growing. The method uses a voxel classification based appearance model, which involves the use of a classifier...... is evaluated within EXACT’09 on a diverse set of CT scans. Results show a favorable combination of a relatively large portion of the tree detected correctly with very few false positives....

  4. Fluid-Structure Simulations of a Ruptured Intracranial Aneurysm: Constant versus Patient-Specific Wall Thickness

    Directory of Open Access Journals (Sweden)

    S. Voß

    2016-01-01

    Full Text Available Computational Fluid Dynamics is intensively used to deepen the understanding of aneurysm growth and rupture in order to support physicians during therapy planning. However, numerous studies considering only the hemodynamics within the vessel lumen found no satisfactory criteria for rupture risk assessment. To improve available simulation models, the rigid vessel wall assumption has been discarded in this work and patient-specific wall thickness is considered within the simulation. For this purpose, a ruptured intracranial aneurysm was prepared ex vivo, followed by the acquisition of local wall thickness using μCT. The segmented inner and outer vessel surfaces served as solid domain for the fluid-structure interaction (FSI simulation. To compare wall stress distributions within the aneurysm wall and at the rupture site, FSI computations are repeated in a virtual model using a constant wall thickness approach. Although the wall stresses obtained by the two approaches—when averaged over the complete aneurysm sac—are in very good agreement, strong differences occur in their distribution. Accounting for the real wall thickness distribution, the rupture site exhibits much higher stress values compared to the configuration with constant wall thickness. The study reveals the importance of geometry reconstruction and accurate description of wall thickness in FSI simulations.

  5. Prosopomorphic vessels from Moesia Superior

    Directory of Open Access Journals (Sweden)

    Nikolić Snežana

    2008-01-01

    Full Text Available The prosopomorphic vessels from Moesia Superior had the form of beakers varying in outline but similar in size. They were wheel-thrown, mould-made or manufactured by using a combination of wheel-throwing and mould-made appliqués. Given that face vessels are considerably scarcer than other kinds of pottery, more than fifty finds from Moesia Superior make an enviable collection. In this and other provinces face vessels have been recovered from military camps, civilian settlements and necropolises, which suggests that they served more than one purpose. It is generally accepted that the faces-masks gave a protective role to the vessels, be it to protect the deceased or the family, their house and possessions. More than forty of all known finds from Moesia Superior come from Viminacium, a half of that number from necropolises. Although tangible evidence is lacking, there must have been several local workshops producing face vessels. The number and technological characteristics of the discovered vessels suggest that one of the workshops is likely to have been at Viminacium, an important pottery-making centre in the second and third centuries.

  6. The composition of collagen in the aneurysm wall of men and women

    NARCIS (Netherlands)

    Villard, C.; Eriksson, P.; Hanemaaijer, R.; Lindeman, J.H.; Hultgren, R.

    2017-01-01

    Background. Loss of vessel wall integrity by degradation is essential for the development of abdominal aortic aneurysm (AAA) and ultimately its rupture. The observed greater rupture rate in women with AAA might be related to gender differences in the biomechanical properties of the aneurysm wall.

  7. Probabilistic Structural Integrity Analysis of Boiling Water Reactor Pressure Vessel under Low Temperature Overpressure Event

    Directory of Open Access Journals (Sweden)

    Hsoung-Wei Chou

    2015-01-01

    Full Text Available The probabilistic structural integrity of a Taiwan domestic boiling water reactor pressure vessel has been evaluated by the probabilistic fracture mechanics analysis. First, the analysis model was built for the beltline region of the reactor pressure vessel considering the plant specific data. Meanwhile, the flaw models which comprehensively simulate all kinds of preexisting flaws along the vessel wall were employed here. The low temperature overpressure transient which has been concluded to be the severest accident for a boiling water reactor pressure vessel was considered as the loading condition. It is indicated that the fracture mostly happens near the fusion-line area of axial welds but with negligible failure risk. The calculated results indicate that the domestic reactor pressure vessel has sufficient structural integrity until doubling of the present end-of-license operation.

  8. Research on wall shear stress considering wall roughness when shear swirling flow vibration cementing

    Science.gov (United States)

    Cui, Zhihua; Ai, Chi; Feng, Fuping

    2017-01-01

    When shear swirling flow vibration cementing, the casing is revolving periodically and eccentrically, which leads to the annulus fluid in turbulent swirling flow state. The wall shear stress is more than that in laminar flow field when conventional cementing. The paper mainly studied the wall shear stress distribution on the borehole wall when shear swirling flow vibration cementing based on the finite volume method. At the same time, the wall roughness affected and changed the turbulent flow near the borehole wall and the wall shear stress. Based on the wall function method, the paper established boundary conditions considering the wall roughness and derived the formula of the wall shear stress. The results showed that the wall roughness significantly increases the wall shear stress. However, the larger the wall roughness, the greater the thickness of mud cake, which weakening the cementing strength. Considering the effects in a comprehensive way, it is discovered that the particle size of solid phase in drilling fluid is about 0.1 mm to get better cementing quality.

  9. Retinal vessel centerline extraction using multiscale matched filters, confidence and edge measures.

    Science.gov (United States)

    Sofka, Michal; Stewart, Charles V

    2006-12-01

    Motivated by the goals of improving detection of low-contrast and narrow vessels and eliminating false detections at nonvascular structures, a new technique is presented for extracting vessels in retinal images. The core of the technique is a new likelihood ratio test that combines matched-filter responses, confidence measures and vessel boundary measures. Matched filter responses are derived in scale-space to extract vessels of widely varying widths. A vessel confidence measure is defined as a projection of a vector formed from a normalized pixel neighborhood onto a normalized ideal vessel profile. Vessel boundary measures and associated confidences are computed at potential vessel boundaries. Combined, these responses form a six-dimensional measurement vector at each pixel. A training technique is used to develop a mapping of this vector to a likelihood ratio that measures the "vesselness" at each pixel. Results comparing this vesselness measure to matched filters alone and to measures based on the Hessian of intensities show substantial improvements, both qualitatively and quantitatively. The Hessian can be used in place of the matched filter to obtain similar but less-substantial improvements or to steer the matched filter by preselecting kernel orientations. Finally, the new vesselness likelihood ratio is embedded into a vessel tracing framework, resulting in an efficient and effective vessel centerline extraction algorithm.

  10. Analytical investigation of laminar flow through expanding or contracting gaps with porous walls

    Directory of Open Access Journals (Sweden)

    M. Jafaryar

    2014-12-01

    Full Text Available Laminar, isothermal, incompressible and viscous flow in a rectangular domain bounded by two moving porous walls, which enable the fluid to enter or exit during successive expansions or contractions is investigated analytically using optimal homotopy asymptotic method (OHAM. OHAM is a powerful method for solving nonlinear problems without depending to the small parameter. The concept of this method is briefly introduced, and it׳s application for this problem is studied. Then, the results are compared with numerical results and the validity of these methods is shown. After this verification, we analyze the effects of some physical applicable parameters to show the efficiency of OHAM for this type of problems. Graphical results are presented to investigate the influence of the non-dimensional wall dilation rate (α and permeation Reynolds number (Re on the velocity, normal pressure distribution and wall shear stress. The present problem for slowly expanding or contracting walls with weak permeability is a simple model for the transport of biological fluids through contracting or expanding vessels.

  11. Abdominal wall fat pad biopsy

    Science.gov (United States)

    Amyloidosis - abdominal wall fat pad biopsy; Abdominal wall biopsy; Biopsy - abdominal wall fat pad ... method of taking an abdominal wall fat pad biopsy . The health care provider cleans the skin on ...

  12. Flattening maps for the visualization of multibranched vessels.

    Science.gov (United States)

    Zhu, Lei; Haker, Steven; Tannenbaum, Allen

    2005-02-01

    In this paper, we present two novel algorithms which produce flattened visualizations of branched physiological surfaces, such as vessels. The first approach is a conformal mapping algorithm based on the minimization of two Dirichlet functionals. From a triangulated representation of vessel surfaces, we show how the algorithm can be implemented using a finite element technique. The second method is an algorithm which adjusts the conformal mapping to produce a flattened representation of the original surface while preserving areas. This approach employs the theory of optimal mass transport. Furthermore, a new way of extracting center lines for vessel fly-throughs is provided.

  13. Automated method for identification and artery-venous classification of vessel trees in retinal vessel networks.

    Directory of Open Access Journals (Sweden)

    Vinayak S Joshi

    Full Text Available The separation of the retinal vessel network into distinct arterial and venous vessel trees is of high interest. We propose an automated method for identification and separation of retinal vessel trees in a retinal color image by converting a vessel segmentation image into a vessel segment map and identifying the individual vessel trees by graph search. Orientation, width, and intensity of each vessel segment are utilized to find the optimal graph of vessel segments. The separated vessel trees are labeled as primary vessel or branches. We utilize the separated vessel trees for arterial-venous (AV classification, based on the color properties of the vessels in each tree graph. We applied our approach to a dataset of 50 fundus images from 50 subjects. The proposed method resulted in an accuracy of 91.44% correctly classified vessel pixels as either artery or vein. The accuracy of correctly classified major vessel segments was 96.42%.

  14. Blood-Vessel Mimicking Structures by Stereolithographic Fabrication of Small Porous Tubes Using Cytocompatible Polyacrylate Elastomers, Biofunctionalization and Endothelialization

    Directory of Open Access Journals (Sweden)

    Birgit Huber

    2016-04-01

    Full Text Available Blood vessel reconstruction is still an elusive goal for the development of in vitro models as well as artificial vascular grafts. In this study, we used a novel photo-curable cytocompatible polyacrylate material (PA for freeform generation of synthetic vessels. We applied stereolithography for the fabrication of arbitrary 3D tubular structures with total dimensions in the centimeter range, 300 µm wall thickness, inner diameters of 1 to 2 mm and defined pores with a constant diameter of approximately 100 µm or 200 µm. We established a rinsing protocol to remove remaining cytotoxic substances from the photo-cured PA and applied thio-modified heparin and RGDC-peptides to functionalize the PA surface for enhanced endothelial cell adhesion. A rotating seeding procedure was introduced to ensure homogenous endothelial monolayer formation at the inner luminal tube wall. We showed that endothelial cells stayed viable and adherent and aligned along the medium flow under fluid-flow conditions comparable to native capillaries. The combined technology approach comprising of freeform additive manufacturing (AM, biomimetic design, cytocompatible materials which are applicable to AM, and biofunctionalization of AM constructs has been introduced as BioRap® technology by the authors.

  15. Blood-Vessel Mimicking Structures by Stereolithographic Fabrication of Small Porous Tubes Using Cytocompatible Polyacrylate Elastomers, Biofunctionalization and Endothelialization

    Science.gov (United States)

    Huber, Birgit; Engelhardt, Sascha; Meyer, Wolfdietrich; Krüger, Hartmut; Wenz, Annika; Schönhaar, Veronika; Tovar, Günter E. M.; Kluger, Petra J.; Borchers, Kirsten

    2016-01-01

    Blood vessel reconstruction is still an elusive goal for the development of in vitro models as well as artificial vascular grafts. In this study, we used a novel photo-curable cytocompatible polyacrylate material (PA) for freeform generation of synthetic vessels. We applied stereolithography for the fabrication of arbitrary 3D tubular structures with total dimensions in the centimeter range, 300 µm wall thickness, inner diameters of 1 to 2 mm and defined pores with a constant diameter of approximately 100 µm or 200 µm. We established a rinsing protocol to remove remaining cytotoxic substances from the photo-cured PA and applied thio-modified heparin and RGDC-peptides to functionalize the PA surface for enhanced endothelial cell adhesion. A rotating seeding procedure was introduced to ensure homogenous endothelial monolayer formation at the inner luminal tube wall. We showed that endothelial cells stayed viable and adherent and aligned along the medium flow under fluid-flow conditions comparable to native capillaries. The combined technology approach comprising of freeform additive manufacturing (AM), biomimetic design, cytocompatible materials which are applicable to AM, and biofunctionalization of AM constructs has been introduced as BioRap® technology by the authors. PMID:27104576

  16. Advanced in-vessel retention design for next generation risk management

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Kune Y.; Hwang, Il Soon [Seoul National University, Seoul (Korea, Republic of)

    1997-12-31

    In the TMI-2 accident, approximately twenty (20) tons of molten core material drained into the lower plenum. Early advanced light water reactor (LWR) designs assumed a lower head failure and incorporated various measures for ex-vessel accident mitigation. However,one of the major findings from the TMI-2 Vessel Investigation Project was that one part of the reactor lower head wall estimated to have attained a temperature of 1100 deg C for about 30 minutes has seemingly experienced a comparatively rapid cooldown with no major threat to the vessel integrity. In this regard, recent empirical and analytical studies have shifted interests to such in-vessel retention designs or strategies as reactor cavity flooding, in-vessel flooding and engineered gap cooling of the vessel. Accurate thermohydrodynamic and creep deformation modeling and rupture prediction are the key to the success in developing practically useful in-vessel accident/risk management strategies. As an advanced in-vessel design concept, this work presents the COrium Attack Syndrome Immunization Structures (COASIS) that are being developed as prospective in-vessel retention devices for a next-generation LWR in concert with existing ex-vessel management measures. Both the engineered gap structures in-vessel (COASISI) and ex-vessel (COASISO) are demonstrated to maintain effective heat transfer geometry during molten core debris attack when applied to the Korean Standard Nuclear Power Plant (KSNPP) reactor. The likelihood of lower head creep rupture during a severe accident is found to be significantly suppressed by the COASIS options. 15 refs., 5 figs., 1 tab. (Author)

  17. Effects of wall condition on flow distributions in arterial modeling: comparison of rigid, dynamic, and compliant walls

    Energy Technology Data Exchange (ETDEWEB)

    He, Fan [Beijing University of Civil Engineering and Architecture, Beijing (China); Hua, Lu; Gao, Li jian [Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China)

    2016-03-15

    Blood flow distributions were evaluated using various computational strategies. Three commonly used wall conditions in arterial modeling were employed, namely rigid, dynamic and compliant walls. The results show that the velocity distributions are similar under rigid and dynamic walls, developing into the Poiseuille flow, but they are blunt under compliant walls. The peak pressure under rigid walls is highest, but the model of dynamic walls has a good approximation of pressure against the model of compliant walls. The results indicate that a model of compliant walls appears to be a computationally and reasonably accurate approximation of blood velocity distributions compared with the analysis under rigid or dynamic walls. Introducing fluid-structure interaction into arterial modeling is necessary to ensure reliable results and information. However, a model of dynamic walls seems to be a computationally inexpensive yet reasonably accurate approximation for pressure.

  18. ORIGINAL ARTICLE Sonographic gallbladder wall thickness in ...

    African Journals Online (AJOL)

    The study population's age ranged from 16 - 78 years, with a mean age and SD of 32±13.2 years. The age parameter was unevenly distributed. →. →. Fig. 1. Longitudinal US image showing site of measurement of gallbladder wall thickness (arrows). Table I. Age distribution of mean gallbladder wall thickness in the study ...

  19. 50 CFR 697.8 - Vessel identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Vessel identification. 697.8 Section 697.8 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION....8 Vessel identification. (a) Vessel name and official number. Each fishing vessel issued a limited...

  20. Mechanosensing in developing lymphatic vessels.

    Science.gov (United States)

    Planas-Paz, Lara; Lammert, Eckhard

    2014-01-01

    The lymphatic vasculature is responsible for fluid homeostasis, transport of immune cells, inflammatory molecules, and dietary lipids. It is composed of a network of lymphatic capillaries that drain into collecting lymphatic vessels and ultimately bring fluid back to the blood circulation. Lymphatic endothelial cells (LECs) that line lymphatic capillaries present loose overlapping intercellular junctions and anchoring filaments that support fluid drainage. When interstitial fluid accumulates within tissues, the extracellular matrix (ECM) swells and pulls the anchoring filaments. This results in opening of the LEC junctions and permits interstitial fluid uptake. The absorbed fluid is then transported within collecting lymphatic vessels, which exhibit intraluminal valves that prevent lymph backflow and smooth muscle cells that sequentially contract to propel lymph.Mechanotransduction involves translation of mechanical stimuli into biological responses. LECs have been shown to sense and respond to changes in ECM stiffness, fluid pressure-induced cell stretch, and fluid flow-induced shear stress. How these signals influence LEC function and lymphatic vessel growth can be investigated by using different mechanotransduction assays in vitro and to some extent in vivo.In this chapter, we will focus on the mechanical forces that regulate lymphatic vessel expansion during embryonic development and possibly secondary lymphedema. In mouse embryos, it has been recently shown that the amount of interstitial fluid determines the extent of lymphatic vessel expansion via a mechanosensory complex formed by β1 integrin and vascular endothelial growth factor receptor-3 (VEGFR3). This model might as well apply to secondary lymphedema.

  1. Motion of red blood cells near microvessel walls: effects of a porous wall layer

    Science.gov (United States)

    HARIPRASAD, DANIEL S.; SECOMB, TIMOTHY W.

    2013-01-01

    A two-dimensional model is used to simulate the motion and deformation of a single mammalian red blood cell (RBC) flowing close to the wall of a microvessel, taking into account the effects of a porous endothelial surface layer (ESL) lining the vessel wall. Migration of RBCs away from the wall leads to the formation of a cell-depleted layer near the wall, which has a large effect on the resistance to blood flow in microvessels. The objective is to examine the mechanical factors causing this migration, including the effects of the ESL. The vessel is represented as a straight parallel-sided channel. The RBC is represented as a set of interconnected viscoelastic elements, suspended in plasma, a Newtonian fluid. The ESL is represented as a porous medium, and plasma flow in the layer is computed using the Brinkman approximation. It is shown that an initially circular cell positioned close to the ESL in a shear flow is deformed into an asymmetric shape. This breaking of symmetry leads to migration away from the wall. With increasing hydraulic resistivity of the layer, the rate of lateral migration increases. It is concluded that mechanical interactions of RBCs flowing in microvessels with a porous wall layer may reduce the rate of lateral migration and hence reduce the width of the cell-depleted zone external to the ESL, relative to the cell-depleted zone that would be formed if the interface between the ESL and free-flowing plasma were replaced by an impermeable boundary. PMID:23493820

  2. A Vessel Active Contour Model for Vascular Segmentation

    Directory of Open Access Journals (Sweden)

    Yun Tian

    2014-01-01

    Full Text Available This paper proposes a vessel active contour model based on local intensity weighting and a vessel vector field. Firstly, the energy function we define is evaluated along the evolving curve instead of all image points, and the function value at each point on the curve is based on the interior and exterior weighted means in a local neighborhood of the point, which is good for dealing with the intensity inhomogeneity. Secondly, a vascular vector field derived from a vesselness measure is employed to guide the contour to evolve along the vessel central skeleton into thin and weak vessels. Thirdly, an automatic initialization method that makes the model converge rapidly is developed, and it avoids repeated trails in conventional local region active contour models. Finally, a speed-up strategy is implemented by labeling the steadily evolved points, and it avoids the repeated computation of these points in the subsequent iterations. Experiments using synthetic and real vessel images validate the proposed model. Comparisons with the localized active contour model, local binary fitting model, and vascular active contour model show that the proposed model is more accurate, efficient, and suitable for extraction of the vessel tree from different medical images.

  3. Cell Wall Remodeling Enzymes Modulate Fungal Cell Wall Elasticity and Osmotic Stress Resistance.

    Science.gov (United States)

    Ene, Iuliana V; Walker, Louise A; Schiavone, Marion; Lee, Keunsook K; Martin-Yken, Hélène; Dague, Etienne; Gow, Neil A R; Munro, Carol A; Brown, Alistair J P

    2015-07-28

    The fungal cell wall confers cell morphology and protection against environmental insults. For fungal pathogens, the cell wall is a key immunological modulator and an ideal therapeutic target. Yeast cell walls possess an inner matrix of interlinked β-glucan and chitin that is thought to provide tensile strength and rigidity. Yeast cells remodel their walls over time in response to environmental change, a process controlled by evolutionarily conserved stress (Hog1) and cell integrity (Mkc1, Cek1) signaling pathways. These mitogen-activated protein kinase (MAPK) pathways modulate cell wall gene expression, leading to the construction of a new, modified cell wall. We show that the cell wall is not rigid but elastic, displaying rapid structural realignments that impact survival following osmotic shock. Lactate-grown Candida albicans cells are more resistant to hyperosmotic shock than glucose-grown cells. We show that this elevated resistance is not dependent on Hog1 or Mkc1 signaling and that most cell death occurs within 10 min of osmotic shock. Sudden decreases in cell volume drive rapid increases in cell wall thickness. The elevated stress resistance of lactate-grown cells correlates with reduced cell wall elasticity, reflected in slower changes in cell volume following hyperosmotic shock. The cell wall elasticity of lactate-grown cells is increased by a triple mutation that inactivates the Crh family of cell wall cross-linking enzymes, leading to increased sensitivity to hyperosmotic shock. Overexpressing Crh family members in glucose-grown cells reduces cell wall elasticity, providing partial protection against hyperosmotic shock. These changes correlate with structural realignment of the cell wall and with the ability of cells to withstand osmotic shock. The C. albicans cell wall is the first line of defense against external insults, the site of immune recognition by the host, and an attractive target for antifungal therapy. Its tensile strength is conferred by

  4. Green walls in Vancouver

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, R. [Sharp and Diamond Landscape Architecture Inc., Vancouver, BC (Canada)

    2007-07-01

    With the renewed interest in design for microclimate control and energy conservation, many cities are implementing clean air initiatives and sustainable planning policies to mitigate the effects of urban climate and the urban heat island effect. Green roofs, sky courts and green walls must be thoughtfully designed to withstand severe conditions such as moisture stress, extremes in temperature, tropical storms and strong desiccating winds. This paper focused on the installation of green wall systems. There are 2 general types of green walls systems, namely facade greening and living walls. Green facades are trellis systems where climbing plants can grow vertically without attaching to the surface of the building. Living walls are part of a building envelope system where plants are actually planted and grown in a wall system. A modular G-SKY Green Wall Panel was installed at the Aquaquest Learning Centre at the Vancouver Aquarium in Stanley Park in September 2006. This green wall panel, which was originally developed in Japan, incorporates many innovative features in the building envelope. It provides an exterior wall covered with 8 species of plants native to the Coastal Temperate Rain Forest. The living wall is irrigated by rainwater collected from the roof, stored in an underground cistern and fed through a drip irrigation system. From a habitat perspective, the building imitates an escarpment. Installation, support systems, irrigation, replacement of modules and maintenance are included in the complete wall system. Living walls reduce the surface temperature of buildings by as much as 10 degrees C when covered with vegetation and a growing medium. The project team is anticipating LEED gold certification under the United States-Canada Green Building Council. It was concluded that this technology of vegetated building envelopes is applicable for acoustical control at airports, biofiltration of indoor air, greywater treatment, and urban agriculture and vertical

  5. Three - dimensional magnetic field observation vessel using magnetic fluid

    OpenAIRE

    櫻井, 勇良

    2011-01-01

    In this study, an observation vessel which could depict magnetic field distributions in threedimensionswas produced. The magnetic field observation vessel was made by putting magnetic fluid and water in a transparent square shaped glass container. Observation of both permanent magnet andelectromagnets was carried out. The movement of the magnetic fluid is different depending on the placement of the magnetic poles. The magnetic fluid showed a tendency to gather near each magnetic pole, when it...

  6. Effect of neoadjuvant chemoradiation and postoperative radiotherapy on expression of heat shock protein 70 (HSP70 in head and neck vessels

    Directory of Open Access Journals (Sweden)

    Gellrich Nils-Claudius

    2011-07-01

    Full Text Available Abstract Background Preoperative radiotherapy and chemotherapy in patients with head and neck cancer result in changes to the vessels that are used to construct microsurgical anastomoses. The aim of the study was to investigate quantitative changes and HSP70 expression of irradiated neck recipient vessels and transplant vessels used for microsurgical anastomoses. Methods Of 20 patients included in this study five patients received neoadjuvant chemoradiation, another five received conventional radiotherapy and 10 patients where treated without previous radiotherapy. During surgical procedure, vessel specimens where obtained by the surgeon. Immunhistochemical staining of HSP70 was performed and quantitative measurement and evaluation of HSP70 was carried out. Results Conventional radiation and neoadjuvant chemoradiation revealed in a thickening of the intima layer of recipient vessels. A increased expression of HSP70 could be detected in the media layer of the recipient veins as well as in the transplant veins of patients treated with neoadjuvant chemoradiation. Radiation and chemoradiation decreased the HSP70 expression of the intima layer in recipient arteries. Conventional radiation led to a decrease of HSP70 expression in the media layer of recipient arteries. Conclusion Our results showed that anticancer drugs can lead to a thickening of the intima layer of transplant and recipient veins and also increase the HSP70 expression in the media layer of the recipient vessels. In contrast, conventional radiation decreased the HSP70 expression in the intima layer of arteries and the media layer of recipient arteries and veins. Comparing these results with wall thickness, it was concluded, that high levels of HSP70 may prevent the intima layer of arteries and the media layer of vein from thickening.

  7. Building America Top Innovations 2012: High-R Walls

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2013-01-01

    This Building America Top Innovations profile describes Building America research on high-R-value walls showing the difference between rated and whole wall R values and the need for vented cladding to reduce condensation potential with some insulation types.

  8. 19 CFR 4.5 - Government vessels.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Government vessels. 4.5 Section 4.5 Customs Duties... VESSELS IN FOREIGN AND DOMESTIC TRADES Arrival and Entry of Vessels § 4.5 Government vessels. (a) No... that is the property of, the U.S. Department of Defense (DoD) will be treated as a Government vessel...

  9. Characterization of atherosclerotic plaque of carotid arteries with histopathological correlation: Vascular wall MR imaging vs. color Doppler ultrasonography (US)

    National Research Council Canada - National Science Library

    Watanabe, Yuji; Nagayama, Masako; Suga, Tsuyoshi; Yoshida, Kazumichi; Yamagata, Sen; Okumura, Akira; Amoh, Yoshiki; Nakashita, Satoru; Van Cauteren, Marc; Dodo, Yoshihiro

    2008-01-01

    To investigate whether the vessel wall MRI of carotid arteries would differentiate at-risk soft plaque from solid fibrous plaque by identifying liquid components more accurately than color Doppler ultrasonography (US...

  10. Absence of lymphatic vessels in the developing human sclera.

    Science.gov (United States)

    Schlereth, Simona L; Neuser, Barbara; Herwig, Martina C; Müller, Annette M; Koch, Konrad R; Reitsamer, Herbert A; Schrödl, Falk; Cursiefen, Claus; Heindl, Ludwig M

    2014-08-01

    The adult sclera is free of lymphatic vessels, but contains a net of blood vessels. Whether and when this selectively lymphangiogenic privilege is achieved during embryologic development is not known yet. Therefore, we investigated the developing human sclera for blood- and lymphatic vessels in 34 abortions/stillborns (12-38 weeks of gestation). The probes were subdivided into three groups (group 1: 12-18 weeks of gestation, n = 10; group 2: 19-23 weeks of gestation, n = 13; group 3: 24-38 weeks of gestation, n = 11), and prepared for paraffin sections followed by immunohistochemistry against CD31 to detect blood vessels, and against lymphatic vessel endothelial hyaluronan receptor-1 (LYVE1)/podoplanin to detect lymphatic vessels. We could show, that in the human episclera distinct CD31 + blood vessels are present as early as week of gestation 13. Their amount increased during pregnancy, whereas stromal CD31 + blood vessels were elevated in early pregnancy and regressed with ongoing pregnancy. In the lamina fusca CD31 + blood vessels were absent at any time point investigated. Single LYVE1 + cells were identified primarily in the episclera; their amount decreased significantly with increasing gestational ages (group 1 compared to group 3: p lymphatic vessels were not detectable in the sclera at any gestational ages analyzed. In contrast to the conjunctiva where LYVE1+/podoplanin + lymphatic vessels were detectable as early as week 17, the amount of LYVE1 + cells in the sclera was highest in early pregnancy (group 1), with a significant decrease during continuing pregnancy (p < 0.001). These findings are the first evidence for a fetal lymphangiogenic privilege of the sclera and show, that the fetal human sclera contains CD31 + blood vessels, but is primarily alymphatic. Our findings suggest a strong expression of selectively antilymphangiogenic factors, making the developing sclera a potential model to discern antilymphangiogenic mechanisms

  11. The oral mucosal surface and blood vessels.

    Science.gov (United States)

    Naumova, Ella A; Dierkes, Tobias; Sprang, Jürgen; Arnold, Wolfgang H

    2013-03-12

    Detailed information about the size of the oral mucosa is scarce in the literature, and those studies that do exist do not take into account the size of the tongue or the enlargement of the surface by the papillae. Because of the various functions of the oral mucosa in the maintenance of oral health, knowledge of its true size may provide a better understanding of the physiology of the oral cavity and some oral diseases and direct future therapeutic strategies. The aim of this study was to determine the total size of the oral mucosa. Five human adult cadaver heads were cut in the median sagittal plane, and the total area of the oral surface was determined using silicon casts. The surface of the tongue was measured with quantitative profilometry. Photographs of oral blood vessels were taken in different areas of the oral mucosa of adult test subjects using intravital microscopy, and the pictures were compared with vessel casts of the oral mucosal capillaries of a maccaca fasciculrais monkey, which was studied using a scanning electron microscope. The results showed that the dorsal side of the tongue comprises a large proportion of the total oral mucosal surface. The surface area of the epithelium increases moving from anterior to posterior on the tongue, and the number of underlying blood vessels increases proportionally. It can be concluded that the back of the tongue plays an important role in the oral resorption of drugs. The results may be of relevance for the delivery and development of oral drug application.

  12. Show-Bix &

    DEFF Research Database (Denmark)

    2014-01-01

    The anti-reenactment 'Show-Bix &' consists of 5 dias projectors, a dial phone, quintophonic sound, and interactive elements. A responsive interface will enable the Dias projectors to show copies of original dias slides from the Show-Bix piece ”March på Stedet”, 265 images in total. The copies...... are made from digital scans of the original dias slides located in the collection of the Museum of Contemporary Art in Roskilde. In front of the audience entering the space and placed on it’s own stand, is an original 60s style telephone with turning dial. Action begins when the audience lift the phone...... and dial a number. Any number will make the Dias change. All numbers are also assigned to specific sound documents: clips form rare interviews and the complete sound-re-enactment of the Show-Bix piece ‘Omringning’ (‘Surrounding’) in five channels (a quintophonie). This was originally produced...

  13. Exact Thermal Analysis of Functionally Graded Cylindrical and Spherical Vessels

    Directory of Open Access Journals (Sweden)

    Vebil Yıldırım

    2017-07-01

    Full Text Available Thermal analyses of radially functionally graded (FG thick-walled a spherical vessel and an infinite cylindrical vessel or a circular annulus are conducted analytically by the steady-state 1-D Fourier heat conduction theory under Dirichlet’s boundary conditions. By employing simple-power material grading pattern the differential equations are obtained in the form of Euler-Cauchy types. Analytical solution of the differential equations gives the temperature field and the heat flux distribution in the radial direction in a closed form. Three different physical metal-ceramic pairs first considered to study the effect of the aspect ratio, which is defined as the inner radius to the outer radius of the structure, on the temperature and heat flux variation along the radial coordinate. Then a parametric study is performed with hypothetic inhomogeneity indexes for varying aspect ratios.

  14. Show and Tell

    DEFF Research Database (Denmark)

    2013-01-01

    Fredag d. 1 november blev Kunsthal Charlottenborg indtaget af performanceprogrammet Show & Tell med et bredspektret program af danske og internationale kunstnere indenfor performance-, lyd- og installationskunst. Programmet præsenterer værker, der undersøger kroppens stadig mere symbiotiske forhold...... og studienævnet på Performance-design. Show & Tell - Performance program: kl. 16.30-19 Adresse: Kunsthal Charlottenborg, Nyhavn 2, 1051 København K...

  15. [Pulmonary blood vessels in goats].

    Science.gov (United States)

    Roos, H; Hegner, K; Vollmerhaus, B

    1999-05-01

    The blood vessels in the lung of the goat, which until now have received little attention, are described in detail for the first time. With regard to the segments of the lung, blood vessels are bronchovascular units in the lobi craniales, lobus medius and lobus accessorius, but bronchoartery units in the lobi caudales. We investigated the types of branches of the Aa. pulmonales dextra et sinistra, the inter- and intraspecific principles of the outlet of the pulmonary veins and the importance of bronchopulmonary segmentation of the lungs.

  16. Simulation of liquid dynamics in a cryogenic mobile vessels

    Directory of Open Access Journals (Sweden)

    E. Lisowski

    2010-07-01

    Full Text Available Technical gases becomes liquid in extremely low temperature ranging minus 200 °C and very high pressure what makes that transportationdevices have to perform very strict requirement. Presented paper shows selected aspect of simulation of liquefied gas sloshing in aspect of requirements that mobile vessels have to fulfill. Mobile vessel which is the object of simulation is a two shell tank with vacuum and layer insulation between shells adapted to 20 ft container. It is assigned for see, railway and road transport and have to follow all of requirements for such transportation systems. Requirements for such tank are enclosed in standard ISO 1496-3 which deals with freight containers and standard EN13530-2 that describes vacuum, cryogenic vessels. The standards EN13530-2 defines that vessels which are to be filled equal or less than 80% should be fitted with surge plates to provide vessel stability and limit dynamic loads. Additionally surge plates area has tobe at least 70% of cross section of the vessel and volume between surge plates shall be not higher than 7.5 m3. Structure of the vessel as well as the surge plate should resist of longitudinal acceleration of 2g. Additionally surge plates shall resists stresses caused by pressure distributed across the area of surge plate and the pressure shall be calculated as mass of liquid between plates and acceleration 2g. In this paper is presented way of simulation of dynamic behavior of liquefied Argon on vessel structure. A numerical methods likeComputational Fluid Dynamics (CFD and Finite Element Analysis (FEA were used for this purpose. Combination of both tools allowedto get pick value of dynamic pressure that arising during acceleration of 2g, which was assumed is 0.2 s and investigate resistance of vessel and container structure. Presented approach is called Fluid – Structure Interaction simulation. In CFD simulation was used Ansys CFX code, while for FEA calculations Pro/Mechanica package.

  17. Anther Wall Formation in Solanaceae Species

    Science.gov (United States)

    CARRIZO GARCÍA, CAROLINA

    2002-01-01

    Anther wall formation was studied in 32 species belonging to 27 genera of Solanaceae. Dicotyledonous and basic types of wall formation were observed, as well as several deviations due to subsequent periclinal divisions in the layers formed (middle layers and sometimes the endothecium). One type of wall formation was observed in each species. Some genera are uniform in their type of wall formation, while others are heterogeneous; a similar situation was observed at the tribal level. Summarizing all reported information on anther wall formation in the Solanaceae, 64 % of species show the basic type, while the remaining 36 % show the dicotyledonous type. Thus, neither type predominates, and no single type characterizes genera, tribes or the entire family. PMID:12451025

  18. Characteristics of blood vessels forming “sausages-on-a-string” patterns during hypertension

    Science.gov (United States)

    Ravnsborg Beierholm, Ulrik; Christian Brings Jacobsen, Jens; Holstein-Rathlou, Niels-Henrik; Alstrøm, Preben

    2007-03-01

    A phenomenon of alternate constrictions and dilatations in blood vessels has been studied for over 50 years. Recently, a theory has been presented involving a Rayleigh type instability. We analyze the model in terms of the lengths of the deformations in relation to the wall thickness, blood pressure and stress. Analytical and numerical results obtained are consistent with experimental data.

  19. Retinal vessel detection and measurement for computer-aided medical diagnosis.

    Science.gov (United States)

    Li, Xiaokun; Wee, William G

    2014-02-01

    Since blood vessel detection and characteristic measurement for ocular retinal images is a fundamental problem in computer-aided medical diagnosis, automated algorithms/systems for vessel detection and measurement are always demanded. To support computer-aided diagnosis, an integrated approach/solution for vessel detection and diameter measurement is presented and validated. In the proposed approach, a Dempster-Shafer (D-S)-based edge detector is developed to obtain initial vessel edge information and an accurate vascular map for a retinal image. Then, the appropriate path and the centerline of a vessel of interest are identified automatically through graph search. Once the vessel path has been identified, the diameter of the vessel will be measured accordingly by the algorithm in real time. To achieve more accurate edge detection and diameter measurement, mixed Gaussian-matched filters are designed to refine the initial detection and measures. Other important medical indices of retinal vessels can also be calculated accordingly based on detection and measurement results. The efficiency of the proposed algorithm was validated by the retinal images obtained from different public databases. Experimental results show that the vessel detection rate of the algorithm is 100 % for large vessels and 89.9 % for small vessels, and the error rate on vessel diameter measurement is less than 5 %, which are all well within the acceptable range of deviation among the human graders.

  20. An in situ optical imaging system for measuring lipid uptake, vessel contraction, and lymph flow in small animal lymphatic vessels

    Science.gov (United States)

    Kassis, Timothy; Weiler, Michael J.; Dixon, J. Brandon

    2012-03-01

    All dietary lipids are transported to venous circulation through the lymphatic system, yet the underlying mechanisms that regulate this process remain unclear. Understanding how the lymphatics functionally respond to changes in lipid load is important in the diagnosis and treatment of lipid and lymphatic related diseases such as obesity, hypercholesterolemia, and lymphedema. Therefore, we sought to develop an in situ imaging system to quantify and correlate lymphatic function as it relates to lipid transport. A custom-built optical set-up provides us with the capability of dual-channel imaging of both high-speed bright-field video and fluorescence simultaneously. This is achieved by dividing the light path into two optical bands. Utilizing high-speed and back-illuminated CCD cameras and post-acquisition image processing algorithms, we have the potential quantify correlations between vessel contraction, lymph flow and lipid concentration of mesenteric lymphatic vessels in situ. Local flow velocity is measured through lymphocyte tracking, vessel contraction through measurements of the vessel walls and lipid uptake through fluorescence intensity tracking of a fluorescent long chain fatty acid analogue, Bodipy FL C16. This system will prove to be an invaluable tool for both scientists studying lymphatic function in health and disease, and those investigating strategies for targeting the lymphatic system with orally delivered drugs.

  1. Bidomain Predictions of Virtual Electrode-Induced Make and Break Excitations around Blood Vessels.

    Science.gov (United States)

    Connolly, Adam J; Vigmond, Edward; Bishop, Martin J

    2017-01-01

    Virtual electrodes formed by field stimulation during defibrillation of cardiac tissue play an important role in eliciting activations. It has been suggested that the coronary vasculature is an important source of virtual electrodes, especially during low-energy defibrillation. This work aims to further the understanding of how virtual electrodes from the coronary vasculature influence defibrillation outcomes. Using the bidomain model, we investigated how field stimulation elicited activations from virtual electrodes around idealized intramural blood vessels. Strength-interval curves, which quantify the stimulus strength required to elicit wavefront propagation from the vessels at different states of tissue refractoriness, were computed for each idealized geometry. Make excitations occurred at late diastolic intervals, originating from regions of depolarization around the vessel. Break excitations occurred at early diastolic intervals, whereby the vessels were able to excite surrounding refractory tissue due to the local restoration of excitability by virtual electrode-induced hyperpolarizations. Overall, strength-interval curves had similar morphologies and underlying excitation mechanisms compared with previous experimental and numerical unipolar stimulation studies of cardiac tissue. Including the presence of the vessel wall increased the field strength required for make excitations but decreased the field strength required for break excitations, and the field strength at which break excitations occurred was generally greater than 5 V/cm. Finally, in a more realistic ventricular slice geometry, the proximity of virtual electrodes around subepicardial vessels was seen to cause break excitations in the form of propagating unstable wavelets to the subepicardial layer. Representing the blood vessel wall microstructure in computational bidomain models of defibrillation is recommended as it significantly alters the electrophysiological response of the vessel to

  2. Green Arctic Patrol Vessel

    Science.gov (United States)

    2011-08-01

    C shows the expected 2030 air temperature, ocean ice, sea state, wind, precipitation, illumination , icing and ceiling for each GAPV operating area...100 to 3,000 feet) • Medium (3,000 to 10,000 feet) • High (>10,000 feet) Illumination • Precipitation Rate Icing3 • Standard • Day • Low...dusk, dawn, moonlit, streetlight lit) • Night • Heavy (>0.3"/hr) • Moderate (0.1-0.3"/hr) • Light (trace-ɘ.1"/hr) • Trace (does not

  3. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation.

    Science.gov (United States)

    Yoshida, Kouki; Sakamoto, Shingo; Kawai, Tetsushi; Kobayashi, Yoshinori; Sato, Kazuhito; Ichinose, Yasunori; Yaoi, Katsuro; Akiyoshi-Endo, Miho; Sato, Hiroko; Takamizo, Tadashi; Ohme-Takagi, Masaru; Mitsuda, Nobutaka

    2013-01-01

    Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs) can regulate secondary wall formation in rice (Oryza sativa) and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S) has very low transcriptional activation ability, but the longer protein (OsSWN2L) and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions) due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications.

  4. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation

    Directory of Open Access Journals (Sweden)

    Kouki eYoshida

    2013-10-01

    Full Text Available Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs can regulate secondary wall formation in rice (Oryza sativa and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S has very low transcriptional activation ability, but the longer protein (OsSWN2L and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications.

  5. Solitonlike attractor for blood vessel tip density in angiogenesis

    Science.gov (United States)

    Bonilla, L. L.; Carretero, M.; Terragni, F.

    2016-12-01

    Recently, numerical simulations of a stochastic model have shown that the density of vessel tips in tumor-induced angiogenesis adopts a solitonlike profile [Sci. Rep. 6, 31296 (2016), 10.1038/srep31296]. In this work, we derive and solve the equations for the soliton collective coordinates that indicate how the soliton adapts its shape and velocity to varying chemotaxis and diffusion. The vessel tip density can be reconstructed from the soliton formulas. While the stochastic model exhibits large fluctuations, we show that the location of the maximum vessel tip density for different replicas follows closely the soliton peak position calculated either by ensemble averages or by solving an alternative deterministic description of the density. The simple soliton collective coordinate equations may also be used to ascertain the response of the vessel network to changes in the parameters and thus to control it.

  6. Thin Wall Iron Castings

    Energy Technology Data Exchange (ETDEWEB)

    J.F. Cuttino; D.M. Stefanescu; T.S. Piwonka

    2001-10-31

    Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.

  7. Timber frame walls

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Brandt, Erik

    2010-01-01

    A ventilated cavity is usually considered good practice for removing moisture behind the cladding of timber framed walls. Timber frame walls with no cavity are a logical alternative as they are slimmer and less expensive to produce and besides the risk of a two-sided fire behind the cladding...

  8. International Divider Walls

    NARCIS (Netherlands)

    Kruis, A.; Sneller, A.C.W.(L.)

    2013-01-01

    The subject of this teaching case is the Enterprise Resource Planning (ERP) system implementation at International Divider Walls, the world market leader in design, production, and sales of divider walls. The implementation in one of the divisions of this multinational company had been successful,

  9. Invasion of lymphatic vessels into the eye after open globe injuries.

    Science.gov (United States)

    Wessel, Julia M; Hofmann-Rummelt, Carmen; Kruse, Friedrich E; Cursiefen, Claus; Heindl, Ludwig M

    2012-06-20

    We analyzed whether lymphatic vessels can be detected in eyes enucleated after an open globe injury. The presence of lymphatic vessels was analyzed immunohistochemically using podoplanin as a specific lymphatic endothelial marker in 21 globes that had been enucleated after open globe injury. The localization of pathologic lymphatic vessels (within the eye wall or inside the eye) was correlated with the mechanism of trauma, anatomic site of perforation or rupture, and time interval between trauma and enucleation. Pathologic lymphatic vessels were detected in 15 of 21 eyes (71%) enucleated after an open globe injury. In 5 globes (24%) they were found within the eye, located in retrocorneal membranes, underneath the sclera, and adjacent to uveal tissue (ciliary body, iris). No significant association was observed between the presence of pathologic lymphatic vessels and the mechanism of trauma (P = 0.598), anatomic site of perforation or rupture (P = 0.303), and time interval between trauma and enucleation (P = 0.145). The human eye can be invaded secondarily by lymphatic vessels if the eye wall is opened by trauma. This mechanism could be important for wound healing, immunologic defense against intruding microorganisms, and autoimmune reactions against intraocular antigens.

  10. Compressibility measurements of gases using externally heated pressure vessels.

    Science.gov (United States)

    Presnall, D. C.

    1971-01-01

    Most of the data collected under conditions of high temperature and pressure have been determined using a thick-walled bomb of carefully measured and fixed volume which is externally heated by an electric furnace or a thermostatically controlled bath. There are numerous variations on the basic method depending on the pressure-temperature range of interest, and the particular gas or gas mixture being studied. The construction and calibration of the apparatus is discussed, giving attention to the pressure vessel, the volume of the bomb, the measurement of pressure, the control and measurement of temperature, and the measurement of the amount and composition of gas in the bomb.

  11. A fasciclin-domain containing gene, ZeFLA11, is expressed exclusively in xylem elements that have reticulate wall thickenings in the stem vascular system of Zinnia elegans cv Envy.

    Science.gov (United States)

    Dahiya, Preeti; Findlay, Kim; Roberts, Keith; McCann, Maureen C

    2006-05-01

    The vascular cylinder of the mature stem of Zinnia elegans cv Envy contains two anatomically distinct sets of vascular bundles, stem bundles and leaf-trace bundles. We isolated a full-length cDNA of ZeFLA11, a fasciclin-domain-containing gene, from a zinnia cDNA library derived from in vitro cultures of mesophyll cells induced to form tracheary elements. Using RNA in situ hybridization, we show that ZeFLA11 is expressed in the differentiating xylem vessels with reticulate type wall thickenings and adjacent parenchyma cells of zinnia stem bundles, but not in the leaf-trace bundles that deposit spiral thickenings. Our results suggest a function for this cell-surface GPI-anchored glycoprotein in secondary wall deposition during differentiation of metaxylem tissue with reticulate vessels.

  12. Right coronary wall cmr in the older asymptomatic advance cohort: positive remodeling and associations with type 2 diabetes and coronary calcium

    Directory of Open Access Journals (Sweden)

    Courtney Brian K

    2010-12-01

    Full Text Available Abstract Background Coronary wall cardiovascular magnetic resonance (CMR is a promising noninvasive approach to assess subclinical atherosclerosis, but data are limited in subjects over 60 years old, who are at increased risk. The purpose of the study was to evaluate coronary wall CMR in an asymptomatic older cohort. Results Cross-sectional images of the proximal right coronary artery (RCA were acquired using spiral black-blood coronary CMR (0.7 mm resolution in 223 older, community-based patients without a history of cardiovascular disease (age 60-72 years old, 38% female. Coronary measurements (total vessel area, lumen area, wall area, and wall thickness had small intra- and inter-observer variabilities (r = 0.93~0.99, all p Conclusions Right coronary wall CMR in asymptomatic older subjects showed increased coronary atherosclerosis in subjects with type 2 diabetes as well as coronary calcification. Coronary wall CMR may contribute to the noninvasive assessment of subclinical coronary atherosclerosis in older, at-risk patient groups.

  13. Commercial Passenger Fishing Vessel Fishery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains the logbook data from U.S.A. Commercial Passenger Fishing Vessels (CPFV) fishing in the U.S.A. EEZ and in waters off of Baja California, from...

  14. Pressure vessel and method therefor

    Energy Technology Data Exchange (ETDEWEB)

    Saunders, Timothy

    2017-09-05

    A pressure vessel includes a pump having a passage that extends between an inlet and an outlet. A duct at the pump outlet includes at least one dimension that is adjustable to facilitate forming a dynamic seal that limits backflow of gas through the passage.

  15. BPC 157 and blood vessels.

    Science.gov (United States)

    Seiwerth, Sven; Brcic, Luka; Vuletic, Lovorka Batelja; Kolenc, Danijela; Aralica, Gorana; Misic, Marija; Zenko, Anita; Drmic, Domagoj; Rucman, Rudolf; Sikiric, Predrag

    2014-01-01

    This review focuses on the described effects of BPC 157 on blood vessels after different types of damage, and elucidate by investigating different aspects of vascular response to injury (endothelium damage, clotting, thrombosis, vasoconstriction, vasodilatation, vasculoneogenesis and edema formation) especially in connection to the healing processes. In this respect, BPC 157 was concluded to be the most potent angiomodulatory agent, acting through different vasoactive pathways and systems (e.g. NO, VEGF, FAK) and leading to optimization of the vascular response followed, as it has to be expected, by optimization of the healing process. Formation of new blood vessels involves two main, partly overlapping mechanisms, angiogenesis and vasculogenesis. The additional mechanism of arteriogenesis is involved in the formation of collaterals. In conjunction with blood vessel function, we at least have to consider leakage of fluid/proteins/plasma, resulting in edema/exudate formation as well as thrombogenesis. Blood vessels are also strongly involved in tumor biology. In this aspect, we have neoangiogenesis resulting in pathological vascularization, vascular invasion resulting in release of metastatic cells and the phenomenon of homing resulting in formation of secondary tumors--metastases.

  16. The determinants of fishing vessel accident severity.

    Science.gov (United States)

    Jin, Di

    2014-05-01

    The study examines the determinants of fishing vessel accident severity in the Northeastern United States using vessel accident data from the U.S. Coast Guard for 2001-2008. Vessel damage and crew injury severity equations were estimated separately utilizing the ordered probit model. The results suggest that fishing vessel accident severity is significantly affected by several types of accidents. Vessel damage severity is positively associated with loss of stability, sinking, daytime wind speed, vessel age, and distance to shore. Vessel damage severity is negatively associated with vessel size and daytime sea level pressure. Crew injury severity is also positively related to the loss of vessel stability and sinking. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. The Disruption of Vessel-Spanning Bubbles with Sloped Fins in Flat-Bottom and 2:1 Elliptical-Bottom Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Gauglitz, Phillip A.; Buchmiller, William C.; Jenks, Jeromy WJ; Chun, Jaehun; Russell, Renee L.; Schmidt, Andrew J.; Mastor, Michael M.

    2010-09-22

    Radioactive sludge was generated in the K-East Basin and K-West Basin fuel storage pools at the Hanford Site while irradiated uranium metal fuel elements from the N Reactor were being stored and packaged. The fuel has been removed from the K Basins, and currently, the sludge resides in the KW Basin in large underwater Engineered Containers. The first phase to the Sludge Treatment Project being led by CH2MHILL Plateau Remediation Company (CHPRC) is to retrieve and load the sludge into sludge transport and storage containers (STSCs) and transport the sludge to T Plant for interim storage. The STSCs will be stored inside T Plant cells that are equipped with secondary containment and leak-detection systems. The sludge is composed of a variety of particulate materials and water, including a fraction of reactive uranium metal particles that are a source of hydrogen gas. If a situation occurs where the reactive uranium metal particles settle out at the bottom of a container, previous studies have shown that a vessel-spanning gas layer above the uranium metal particles can develop and can push the overlying layer of sludge upward. The major concern, in addition to the general concern associated with the retention and release of a flammable gas such as hydrogen, is that if a vessel-spanning bubble (VSB) forms in an STSC, it may drive the overlying sludge material to the vents at the top of the container. Then it may be released from the container into the cell’s secondary containment system at T Plant. A previous study demonstrated that sloped walls on vessels, both cylindrical coned-shaped vessels and rectangular vessels with rounded ends, provided an effective approach for disrupting a VSB by creating a release path for gas as a VSB began to rise. Based on the success of sloped-wall vessels, a similar concept is investigated here where a sloped fin is placed inside the vessel to create a release path for gas. A key potential advantage of using a sloped fin compared to a

  18. Talking with TV shows

    DEFF Research Database (Denmark)

    Sandvik, Kjetil; Laursen, Ditte

    2014-01-01

    User interaction with radio and television programmes is not a new thing. However, with new cross-media production concepts such as X Factor and Voice, this is changing dramatically. The second-screen logic of these productions encourages viewers, along with TV’s traditional one-way communication...... mode, to communicate on interactive (dialogue-enabling) devices such as laptops, smartphones and tablets. Using the TV show Voice as our example, this article shows how the technological and situational set-up of the production invites viewers to engage in new ways of interaction and communication....... More specifically, the article demonstrates how online comments posted on the day of Voice’s 2012 season finale can be grouped into four basic action types: (1) Invitation to consume content, (2) Request for participation, (3) Request for collaboration and (4) Online commenting. These action types...

  19. Um show de cacau

    OpenAIRE

    Rezende, José Francisco; UNIGRANRIO / PPGA; Mello, Simone; UNIGRANRIO

    2016-01-01

    O caso de ensino apresenta a trajetória de Alexandre Tadeu da Costa e da chocolateria Cacau Show. Seu objetivo é levar os estudantes a identificar alternativas e tomar decisões sobre posicionamento para continuidade do desenvolvimento de vantagens competitivas, sustentação de competência logística e possíveis abordagens ao mercado externo. 

  20. 46 CFR 42.05-63 - Ship(s) and vessel(s).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Ship(s) and vessel(s). 42.05-63 Section 42.05-63... BY SEA Definition of Terms Used in This Subchapter § 42.05-63 Ship(s) and vessel(s). The terms ship(s) and vessel(s) are interchangeable or synonymous words, and include every description of watercraft...

  1. Solar Walls in tsbi3

    DEFF Research Database (Denmark)

    Wittchen, Kim Bjarne

    tsbi3 is a user-friendly and flexible computer program, which provides support to the design team in the analysis of the indoor climate and the energy performance of buildings. The solar wall module gives tsbi3 the capability of simulating solar walls and their interaction with the building....... This version, C, of tsbi3 is capable of simulating five types of solar walls say: mass-walls, Trombe-walls, double Trombe-walls, internally ventilated walls and solar walls for preheating ventilation air. The user's guide gives a description of the capabilities and how to simulate solar walls in tsbi3....

  2. Sonographic assessment of splanchnic arteries and the bowel wall

    Energy Technology Data Exchange (ETDEWEB)

    Dietrich, C.F. [Medical Department II, Caritas-Krankenhaus, Uhlandstr. 7, D-97980 Bad Mergentheim (Germany)], E-mail: Christoph.dietrich@ckbm.de; Jedrzejczyk, M.; Ignee, A. [Medical Department II, Caritas-Krankenhaus, Uhlandstr. 7, D-97980 Bad Mergentheim (Germany)

    2007-11-15

    The intestinal wall can be visualized using high resolution transabdominal ultrasound. The normal intestinal wall thickness in the terminal ileum, cecum, and right and left colon is <2 mm when examined with graded compression. It is important to appreciate that a contracted intestinal segment can be misinterpreted as a thickened wall. Vascularisation can be mainly displayed in the second hyperechoic layer (submucosal layer) as well as vessels penetrating the muscularis propria. Imaging of the gastrointestinal wall is dependent on the experience of the examiner as well dependent on the equipment used. Acute or chronic inflammation of the intestinal wall is accompanied by increased perfusion of the mesentery, which can be displayed non-quantitatively with colour duplex. In contrast, ischemia is characterised by hypoperfusion of the mesenteric arteries and the bowel wall. The most promising sonographic approach in assessing splanchnic arteries and the bowel wall is combining the analysis of superior and inferior mesenteric inflow by pulsed Doppler scanning (systolic and diastolic velocities, resistance index) with the end-organ vascularity by colour Doppler imaging diminishing the influence of examination technique only displaying bowel wall vascularity. Colour Doppler imaging has been described as helpful in a variety of gastrointestinal disorders, particularly in patients with Crohn's disease, celiac disease, mesenteric artery stenosis and other ischemic gastrointestinal diseases, graft versus host disease and hemorrhagic segmental colitis.

  3. Aqueous Solution Vessel Thermal Model Development II

    Energy Technology Data Exchange (ETDEWEB)

    Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-10-28

    The work presented in this report is a continuation of the work described in the May 2015 report, “Aqueous Solution Vessel Thermal Model Development”. This computational fluid dynamics (CFD) model aims to predict the temperature and bubble volume fraction in an aqueous solution of uranium. These values affect the reactivity of the fissile solution, so it is important to be able to calculate them and determine their effects on the reaction. Part A of this report describes some of the parameter comparisons performed on the CFD model using Fluent. Part B describes the coupling of the Fluent model with a Monte-Carlo N-Particle (MCNP) neutron transport model. The fuel tank geometry is the same as it was in the May 2015 report, annular with a thickness-to-height ratio of 0.16. An accelerator-driven neutron source provides the excitation for the reaction, and internal and external water cooling channels remove the heat. The model used in this work incorporates the Eulerian multiphase model with lift, wall lubrication, turbulent dispersion and turbulence interaction. The buoyancy-driven flow is modeled using the Boussinesq approximation, and the flow turbulence is determined using the k-ω Shear-Stress-Transport (SST) model. The dispersed turbulence multiphase model is employed to capture the multiphase turbulence effects.

  4. Vessel tree extraction using locally optimal paths

    DEFF Research Database (Denmark)

    Lo, Pechin Chien Pau; van Ginneken, Bram; de Bruijne, Marleen

    2010-01-01

    This paper proposes a method to extract vessel trees by continually extending detected branches with locally optimal paths. Our approach uses a cost function from a multi scale vessel enhancement filter. Optimal paths are selected based on rules that take into account the geometric characteristics...... of the vessel tree. Experiments were performed on 10 low dose chest CT scans for which the pulmonary vessel trees were extracted. The proposed method is shown to extract a better connected vessel tree and extract more of the small peripheral vessels in comparison to applying a threshold on the output...

  5. Electrically conductive containment vessel for molten aluminum

    Science.gov (United States)

    Holcombe, C.E.; Scott, D.G.

    1984-06-25

    The present invention is directed to a containment vessel which is particularly useful in melting aluminum. The vessel of the present invention is a multilayered vessel characterized by being electrically conductive, essentially nonwettable by and nonreactive with molten aluminum. The vessel is formed by coating a tantalum substrate of a suitable configuration with a mixture of yttria and particulate metal 10 borides. The yttria in the coating inhibits the wetting of the coating while the boride particulate material provides the electrical conductivity through the vessel. The vessel of the present invention is particularly suitable for use in melting aluminum by ion bombardment.

  6. Taking in a Show.

    Science.gov (United States)

    Boden, Timothy W

    2016-01-01

    Many medical practices have cut back on education and staff development expenses, especially those costs associated with conventions and conferences. But there are hard-to-value returns on your investment in these live events--beyond the obvious benefits of acquired knowledge and skills. Major vendors still exhibit their services and wares at many events, and the exhibit hall is a treasure-house of information and resources for the savvy physician or administrator. Make and stick to a purposeful plan to exploit the trade show. You can compare products, gain new insights and ideas, and even negotiate better deals with representatives anxious to realize returns on their exhibition investments.

  7. Easy Come, Easy Go: Capillary Forces Enable Rapid Refilling of Embolized Primary Xylem Vessels.

    Science.gov (United States)

    Rolland, Vivien; Bergstrom, Dana M; Lenné, Thomas; Bryant, Gary; Chen, Hua; Wolfe, Joe; Holbrook, N Michele; Stanton, Daniel E; Ball, Marilyn C

    2015-08-01

    Protoxylem plays an important role in the hydraulic function of vascular systems of both herbaceous and woody plants, but relatively little is known about the processes underlying the maintenance of protoxylem function in long-lived tissues. In this study, embolism repair was investigated in relation to xylem structure in two cushion plant species, Azorella macquariensis and Colobanthus muscoides, in which vascular water transport depends on protoxylem. Their protoxylem vessels consisted of a primary wall with helical thickenings that effectively formed a pit channel, with the primary wall being the pit channel membrane. Stem protoxylem was organized such that the pit channel membranes connected vessels with paratracheal parenchyma or other protoxylem vessels and were not exposed directly to air spaces. Embolism was experimentally induced in excised vascular tissue and detached shoots by exposing them briefly to air. When water was resupplied, embolized vessels refilled within tens of seconds (excised tissue) to a few minutes (detached shoots) with water sourced from either adjacent parenchyma or water-filled vessels. Refilling occurred in two phases: (1) water refilled xylem pit channels, simplifying bubble shape to a rod with two menisci; and (2) the bubble contracted as the resorption front advanced, dissolving air along the way. Physical properties of the protoxylem vessels (namely pit channel membrane porosity, hydrophilic walls, vessel dimensions, and helical thickenings) promoted rapid refilling of embolized conduits independent of root pressure. These results have implications for the maintenance of vascular function in both herbaceous and woody species, because protoxylem plays a major role in the hydraulic systems of leaves, elongating stems, and roots. © 2015 American Society of Plant Biologists. All Rights Reserved.

  8. From Soft Walls to Infrared Branes

    CERN Document Server

    von Gersdorff, Gero

    2010-01-01

    Five dimensional warped spaces with soft walls are generalizations of the standard Randall-Sundrum compactifications, where instead of an infrared brane one has a curvature singularity (with vanishing warp factor) at finite proper distance in the bulk. We project the physics near the singularity onto a hypersurface located a small distance away from it in the bulk. This results in a completely equivalent description of the soft wall in terms of an effective infrared brane, hiding any singular point. We perform explicitly this calculation for two classes of soft wall backgrounds used in the literature. The procedure has several advantages. It separates in a clean way the physics of the soft wall from the physics of the five dimensional bulk, facilitating a more direct comparison with standard two-brane warped compactifications. Moreover, consistent soft walls show a sort of universal behavior near the singularity which is reflected in the effective brane Lagrangian. Thirdly, for many purposes, a good approxima...

  9. Green Walls Utilizing Internet of Things

    Directory of Open Access Journals (Sweden)

    Andrejs BONDAREVS

    2015-09-01

    Full Text Available A wireless sensor network was used to automatically control the life-support equipment of a green wall and to measure its influence on the air quality. Temperature, relative humidity, particulate matter, volatile organic compound and carbon dioxide were monitored during different tests. Green wall performance on improving the air quality and the influence of the air flow through the green wall on its performance were studied. The experimental results show that the green wall is effective to absorb particulate matter and volatile organic compound. The air flow through the green wall significantly increases the performance. The built-in fan increases the absorption rate of particulate matter by 8 times and that of formaldehyde by 3 times.

  10. Extrapleural Inner Thoracic Wall Lesions: Multidetector CT Findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Soo; Kim, Young Tong; Jou, Sung Shik [Soonchunhyang University, Cheonan Hospital, Cheonan (Korea, Republic of)

    2010-06-15

    The extrapleural space is external to the parietal pleura in the thorax. The structures within and adjacent to this region include the fat pad, endothoracic fascia, intercostal muscles, connective tissue, nerves, vessels, and ribs. Further, the space is divided into the inner and outer thoracic wall by the innermost intercostal muscle. Extrapleural lesions in the inner thoracic wall are classified as air-containing lesions, fat-containing lesions, and soft tissue-containing lesions according on their main component. Air-containing lesions include extrapleural air from direct chest trauma and extrapleural extension from pneumomediastinum. Prominent extrapleural fat is seen in decreased lung volume conditions, and can also be seen in normal individuals. Soft tissue-containing lesions include extrapleural extensions from a pleural or chest wall infection as well as tumors and extrapleural hematoma. We classify extrapleural lesions in the inner thoracic wall and illustrate their imaging findings

  11. Thermal insulating barrier and neutron shield providing integrated protection for a nuclear reactor vessel

    Science.gov (United States)

    Schreiber, Roger B.; Fero, Arnold H.; Sejvar, James

    1997-01-01

    The reactor vessel of a nuclear reactor installation which is suspended from the cold leg nozzles in a reactor cavity is provided with a lower thermal insulating barrier spaced from the reactor vessel to form a chamber which can be flooded with cooling water through passive valving to directly cool the reactor vessel in the event of a severe accident. The passive valving also includes bistable vents at the upper end of the thermal insulating barrier for releasing steam. A removable, modular neutron shield extending around the upper end of the reactor cavity below the nozzles forms with the upwardly and outwardly tapered transition on the outer surface of the reactor vessel, a labyrinthine channel which reduces neutron streaming while providing a passage for the escape of steam during a severe accident, and for the cooling air which is circulated along the reactor cavity walls outside the thermal insulating barrier during normal operation of the reactor.

  12. Sound waves in two-dimensional ducts with sinusoidal walls

    Science.gov (United States)

    Nayfeh, A. H.

    1974-01-01

    The method of multiple scales is used to analyze the wave propagation in two-dimensional hard-walled ducts with sinusoidal walls. For traveling waves, resonance occurs whenever the wall wavenumber is equal to the difference of the wavenumbers of any two duct acoustic modes. The results show that neither of these resonating modes could occur without strongly generating the other.

  13. Seismic Performance of Precast Polystyrene RC Walls

    Directory of Open Access Journals (Sweden)

    Wibowo Ari

    2017-01-01

    Full Text Available Precast concrete structure such as precast wall is a concept that is growing rapidly these days. However, the earthquake resistance is believed to be one of its drawbacks. Additionally, the large weight of solid elements also increase the building weight significantly which consequently increase the earthquake base shear force as well. Therefore, investigation on the seismic performance of precast concrete wall has been carried out. Three RC wall specimens using wire mesh reinforcement and EPS (Extended Polystyrene System panel have been tested. This wall was designed as a structural wall that was capable in sustaining lateral loads (in-plane yet were lightweight to reduce the total weight of the building. Parameter observed was the ratio of height to width (aspect ratio of wall of 1.0, 1.5 and 2.0 respectively with the aim to study the behaviour of brittle to ductile transition of the wall. Incremental static load tests were conducted until reaching peak load and then followed by displacement control until failure. Several data were measured at every stage of loading comprising lateral load-displacement behaviour, ultimate strength and collapse mechanism. The outcomes showed that precast concrete walls with a steel wire and EPS panel filler provided considerably good resistance against lateral load.

  14. Showing Value (Editorial

    Directory of Open Access Journals (Sweden)

    Denise Koufogiannakis

    2009-06-01

    Full Text Available When Su Cleyle and I first decided to start Evidence Based Library and Information Practice, one of the things we agreed upon immediately was that the journal be open access. We knew that a major obstacle to librarians using the research literature was that they did not have access to the research literature. Although Su and I are both academic librarians who can access a wide variety of library and information literature from our institutions, we belong to a profession where not everyone has equal access to the research in our field. Without such access to our own body of literature, how can we ever hope for practitioners to use research evidence in their decision making? It would have been contradictory to the principles of evidence based library and information practice to do otherwise.One of the specific groups we thought could use such an open access venue for discovering research literature was school librarians. School librarians are often isolated and lacking access to the research literature that may help them prove to stakeholders the importance of their libraries and their role within schools. Certainly, school libraries have been in decline and the use of evidence to show value is needed. As Ken Haycock noted in his 2003 report, The Crisis in Canada’s School Libraries: The Case for Reform and Reinvestment, “Across the country, teacher-librarians are losing their jobs or being reassigned. Collections are becoming depleted owing to budget cuts. Some principals believe that in the age of the Internet and the classroom workstation, the school library is an artifact” (9. Within this context, school librarians are looking to our research literature for evidence of the impact that school library programs have on learning outcomes and student success. They are integrating that evidence into their practice, and reflecting upon what can be improved locally. They are focusing on students and showing the impact of school libraries and

  15. Timber frame walls

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Brandt, Erik

    2010-01-01

    A ventilated cavity is usually considered good practice for removing moisture behind the cladding of timber framed walls. Timber frame walls with no cavity are a logical alternative as they are slimmer and less expensive to produce and besides the risk of a two-sided fire behind the cladding...... is reduced. To investigate the possibilities, full-size wall elements with wooden cladding and different cavity design, type of cladding and type of wind barrier were exposed to natural climate on the outside and to a humid indoor climate on the inside. During the exposure period parts of the vapour barrier...

  16. The impact of vessel speed reduction on port accidents.

    Science.gov (United States)

    Chang, Young-Tae; Park, Hyosoo

    2016-03-19

    Reduced-speed zones (RSZs) have been designated across the world to control emissions from ships and prevent mammal strikes. While some studies have examined the effectiveness of speed reduction on emissions and mammal preservation, few have analyzed the effects of reduced ship speed on vessel safety. Those few studies have not yet measured the relationship between vessel speed and accidents by using real accident data. To fill this gap in the literature, this study estimates the impact of vessel speed reduction on vessel damages, casualties and frequency of vessel accidents. Accidents in RSZ ports were compared to non-RSZ ports by using U.S. Coast Guard data to capture the speed reduction effects. The results show that speed reduction influenced accident frequency as a result of two factors, the fuel price and the RSZ designation. Every $10 increase in the fuel price led to a 10.3% decrease in the number of accidents, and the RSZ designation reduced vessel accidents by 47.9%. However, the results do not clarify the exact impact of speed reduction on accident casualty. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Color doppler in diagnosis of pathological changes in blood vessels

    Directory of Open Access Journals (Sweden)

    Mladenović Saša

    2014-01-01

    Full Text Available Color Doppler ultrasound is a method that allows noninvasive imaging of blood flow through a blood vessel and analysis of blood vessels, which can be made to flow disturbance and the presence of plaque and narrowing of the blood vessel. Color Doppler ultrasonography allows early detection of pathological changes in blood vessels, which contributes to adequate preventive and therapeutic procedures in the prevention of cerebrovascular disorders. The aim of this paper is to demonstrate the importance of color Doppler ultrasound blood vessels in the diagnosis of pathological changes in the blood vessels of the neck. To create a work used the material of the Cabinet of color Doppler ultrasonography of the Health Center in Donja Gusterica in a prospective study of a random sample of 60 patients were reviewed in January 2014. Gender analysis examined patients, women were 32 (53.33% and 28 men (46.67%. Looking at the age of examined patients, we have found that most of them 43 (71.67% over the age of 50 years, while we found 17 (28.33% patients under 50 years. Atherosclerotic plaques were diagnosed in 36, a change in the shape of the carotid arteries in 29 patients. Atherosclerotic plaque, we usually find the bifurcation ACC and the Origin ACI in 23 (63.89%. Duplex sonography shows what angioneurologists and vascular surgeons are most interested in: the morphology of arterial lesions and hemodynamic effects.

  18. Tumor Vessel Compression Hinders Perfusion of Ultrasonographic Contrast Agents1

    Science.gov (United States)

    Galiè, Mirco; D'Onofrio, Mirko; Montani, Maura; Amici, Augusto; Calderan, Laura; Marzola, Pasquina; Benati, Donatella; Merigo, Flavia; Marchini, Cristina; Sbarbati, Andrea

    2005-01-01

    Abstract Contrast-enhanced ultrasound (CEUS) is an advanced approach to in vivo assessment of tumor vascularity and is being increasingly adopted in clinical oncology. It is based on 1- to 10 µm-sized gas microbubbles, which can cross the capillary beds of the lungs and are effective echo enhancers. It is known that high cell density, high transendothelial fluid exchange, and poorly functioning lymphatic circulation all provoke solid stress, which compresses vessels and drastically reduces tumor blood flow. Given their size, we supposed that the perfusion of microbubbles is affected by anatomic features of tumor vessels more than are contrast agents traditionally used in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Here, we compared dynamic information obtained from CEUS and DCE-MRI on two experimental tumor models exhibiting notable differences in vessel anatomy. We found that tumors with small, flattened vessels show a much higher resistance to microbubble perfusion than to MRI contrast agents, and appear scarcely vascularized at CEUS examination, despite vessel volume adequate for normal function. Thus, whereas CEUS alone could induce incorrect diagnosis when tumors have small or collapsed vessels, integrated analysis using CEUS and DCE-MRI allows in vivo identification of tumors with a vascular profile frequently associated with malignant phenotypes. PMID:15967105

  19. Tumor Vessel Compression Hinders Perfusion of Ultrasonographic Contrast Agents

    Directory of Open Access Journals (Sweden)

    Mirco Galiè

    2005-05-01

    Full Text Available Contrast-enhanced ultrasound (CEUS is an advanced approach to in vivo assessment of tumor vascularity and is being increasingly adopted in clinical oncology. It is based on 1- to 10 μm-sized gas microbubbles, which can cross the capillary beds of the lungs and are effective echo enhancers. It is known that high cell density, high transendothelial fluid exchange, and poorly functioning lymphatic circulation all provoke solid stress, which compresses vessels and drastically reduces tumor blood flow. Given their size, we supposed that the perfusion of microbubbles is affected by anatomic features of tumor vessels more than are contrast agents traditionally used in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI. Here, we compared dynamic information obtained from CEUS and DCE-MRI on two experimental tumor models exhibiting notable differences in vessel anatomy. We found that tumors with small, flattened vessels show a much higher resistance to microbubble perfusion than to MRI contrast agents, and appear scarcely vascularized at CEUS examination, despite vessel volume adequate for normal function. Thus, whereas CEUS alone could induce incorrect diagnosis when tumors have small or collapsed vessels, integrated analysis using CEUS and DCE-MRI allows in vivo identification of tumors with a vascular profile frequently associated with malignant phenotypes.

  20. A Measure of Similarity Between Trajectories of Vessels

    Directory of Open Access Journals (Sweden)

    Le QI

    2016-03-01

    Full Text Available The measurement of similarity between trajectories of vessels is one of the kernel problems that must be addressed to promote the development of maritime intelligent traffic system (ITS. In this study, a new model of trajectory similarity measurement was established to improve the data processing efficiency in dynamic application and to reflect actual sailing behaviors of vessels. In this model, a feature point detection algorithm was proposed to extract feature points, reduce data storage space and save computational resources. A new synthesized distance algorithm was also created to measure the similarity between trajectories by using the extracted feature points. An experiment was conducted to measure the similarity between the real trajectories of vessels. The growth of these trajectories required measurements to be conducted under different voyages. The results show that the similarity measurement between the vessel trajectories is efficient and correct. Comparison of the synthesized distance with the sailing behaviors of vessels proves that results are consistent with actual situations. The experiment results demonstrate the promising application of the proposed model in studying vessel traffic and in supplying reliable data for the development of maritime ITS.

  1. Semi-automated retinal vessel analysis in nonmydriatic fundus photography.

    Science.gov (United States)

    Schuster, Alexander Karl-Georg; Fischer, Joachim Ernst; Vossmerbaeumer, Urs

    2014-02-01

    Funduscopic assessment of the retinal vessels may be used to assess the health status of microcirculation and as a component in the evaluation of cardiovascular risk factors. Typically, the evaluation is restricted to morphological appreciation without strict quantification. Our purpose was to develop and validate a software tool for semi-automated quantitative analysis of retinal vasculature in nonmydriatic fundus photography. matlab software was used to develop a semi-automated image recognition and analysis tool for the determination of the arterial-venous (A/V) ratio in the central vessel equivalent on 45° digital fundus photographs. Validity and reproducibility of the results were ascertained using nonmydriatic photographs of 50 eyes from 25 subjects recorded from a 3DOCT device (Topcon Corp.). Two hundred and thirty-three eyes of 121 healthy subjects were evaluated to define normative values. A software tool was developed using image thresholds for vessel recognition and vessel width calculation in a semi-automated three-step procedure: vessel recognition on the photograph and artery/vein designation, width measurement and calculation of central retinal vessel equivalents. Mean vessel recognition rate was 78%, vessel class designation rate 75% and reproducibility between 0.78 and 0.91. Mean A/V ratio was 0.84. Application on a healthy norm cohort showed high congruence with prior published manual methods. Processing time per image was one minute. Quantitative geometrical assessment of the retinal vasculature may be performed in a semi-automated manner using dedicated software tools. Yielding reproducible numerical data within a short time leap, this may contribute additional value to mere morphological estimates in the clinical evaluation of fundus photographs. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  2. Adaptive wall technology for minimization of wall interferences in transonic wind tunnels

    Science.gov (United States)

    Wolf, Stephen W. D.

    1988-01-01

    Modern experimental techniques to improve free air simulations in transonic wind tunnels by use of adaptive wall technology are reviewed. Considered are the significant advantages of adaptive wall testing techniques with respect to wall interferences, Reynolds number, tunnel drive power, and flow quality. The application of these testing techniques relies on making the test section boundaries adjustable and using a rapid wall adjustment procedure. A historical overview shows how the disjointed development of these testing techniques, since 1938, is closely linked to available computer support. An overview of Adaptive Wall Test Section (AWTS) designs shows a preference for use of relatively simple designs with solid adaptive walls in 2- and 3-D testing. Operational aspects of AWTS's are discussed with regard to production type operation where adaptive wall adjustments need to be quick. Both 2- and 3-D data are presented to illustrate the quality of AWTS data over the transonic speed range. Adaptive wall technology is available for general use in 2-D testing, even in cryogenic wind tunnels. In 3-D testing, more refinement of the adaptive wall testing techniques is required before more widespread use can be planned.

  3. AFSC/FMA/Vessel Assessment Logging

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Vessels fishing trawl gear, vessels fishing hook-and-line and pot gear that are also greater than 57.5 feet overall, and shoreside and floating processing facilities...

  4. Hawaii Abandoned Vessel Inventory, Hawaii Island

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Hawaii Island. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  5. US Virgin Islands Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for US Virgin Islands. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of...

  6. Hawaii Abandoned Vessel Inventory, Midway Island, NWHI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Midway Island, NWHI. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of...

  7. Hawaii Abandoned Vessel Inventory, Kure, NWHI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Kure, NWHI. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  8. Actemra Approved for Certain Blood Vessel Inflammation

    Science.gov (United States)

    ... 165836.html Actemra Approved for Certain Blood Vessel Inflammation Drug will treat adults with a condition called ... to treat adults with giant cell arteritis, an inflammation of the blood vessels (vasculitis). In a media ...

  9. Hawaii Abandoned Vessel Inventory, Maro Reef, NWHI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Maro Reef, NWHI. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  10. PCs and networking for oceanographic research vessels

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, R.G.P.; Desa, E.; Vithayathil, G.

    This paper, first describes briefly the evolution of data acquisition techniques and different system implementation, on board research vessels. A data acquisition system being developed for a coastal research vessel is then described which is based...

  11. Hawaii Abandoned Vessel Inventory, Lisianski Island, NWHI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Lisianski Island, NWHI. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction...

  12. Transitional Flow in an Arteriovenous Fistula: Effect of Wall Distensibility

    Science.gov (United States)

    McGah, Patrick; Leotta, Daniel; Beach, Kirk; Aliseda, Alberto

    2012-11-01

    Arteriovenous fistulae are created surgically to provide adequate access for dialysis in patients with end-stage renal disease. Transitional flow and the subsequent pressure and shear stress fluctuations are thought to be causative in the fistula failure. Since 50% of fistulae require surgical intervention before year one, understanding the altered hemodynamic stresses is an important step toward improving clinical outcomes. We perform numerical simulations of a patient-specific model of a functioning fistula reconstructed from 3D ultrasound scans. Rigid wall simulations and fluid-structure interaction simulations using an in-house finite element solver for the wall deformations were performed and compared. In both the rigid and distensible wall cases, transitional flow is computed in fistula as evidenced by aperiodic high frequency velocity and pressure fluctuations. The spectrum of the fluctuations is much more narrow-banded in the distensible case, however, suggesting a partial stabilizing effect by the vessel elasticity. As a result, the distensible wall simulations predict shear stresses that are systematically 10-30% lower than the rigid cases. We propose a possible mechanism for stabilization involving the phase lag in the fluid work needed to deform the vessel wall. Support from an NIDDK R21 - DK08-1823.

  13. Dry wall Kras 2011

    Directory of Open Access Journals (Sweden)

    Domen Zupančič

    2012-01-01

    Full Text Available Despite the modesty of hiska, they show a simple understanding of corbelling technique. One could say they are all examples of human landscape cultivation. Although there is no evident common line when comparing all types of hiska, the cunning eye may observe one shared feature: the positioning of the entrance. More or less all the documented shelters have south or south-western facing entrances. The burja is a cold northerly wind; from the south (Adriatic Sea the winds are warmer. When resting, the setting sun is taken as a sign of the ending of the working day and a reward for the whole day’s efforts. Entrances are the only openings to these structures, and they should serve as well as possible - to watch over the crops, to wait when hunting, to enjoy the calm of evening light, to breathe the sea wind.The syntax of the architectural language of layering stone and shaping the pattern of the landscape remain an inventive realisation of spatial ideas from the past until today. Not only ideas of shaping space - these ideas are basic interventions in the natural habitat which contribute to survival. Culture and an awareness of its values are the origins of local development and reasonable heritage preservation. The next step are tutorial days with workshops on how to build dry stone structures, walls and other stone architecture, as the DSWA organisation in the UK is doing.

  14. Anterior vaginal wall repair

    Science.gov (United States)

    ... may have you: Learn pelvic floor muscle exercises ( Kegel exercises ) Use estrogen cream in your vagina Try ... repair; Urinary incontinence - vaginal wall repair Patient Instructions Kegel exercises - self-care Self catheterization - female Suprapubic catheter ...

  15. Advanced walling systems

    CSIR Research Space (South Africa)

    De Villiers, A

    2010-01-01

    Full Text Available The question addressed by this chapter is: How should advanced walling systems be planned, designed, built, refurbished, and end their useful lives, to classify as smart, sustainable, green or eco-building environments?...

  16. Assessment of W7-X plasma vessel pressurisation in case of LOCA taking into account in-vessel components

    Energy Technology Data Exchange (ETDEWEB)

    Urbonavičius, E., E-mail: Egidijus.Urbonavicius@lei.lt; Povilaitis, M., E-mail: Mantas.Povilaitis@lei.lt; Kontautas, A., E-mail: Aurimas.Kontautas@lei.lt

    2015-11-15

    Highlights: • Analysis of the vacuum vessel response to the LOCA in W7-X was performed using lumped-parameter codes COCOSYS and ASTEC. • Benchmarking of the results received with two codes provides more confidence in results and helps in identification of possible important differences in the modelling. • The performed analysis answered the questions set in the installed plasma vessel venting system during overpressure of PV in case of 40 mm diameter LOCA in “baking” mode. • Differences in time until opening the burst disk observed in ASTEC and COCOSYS results are caused by differences in heat transfer modelling. - Abstract: This paper presents the analysis of W7-X vacuum vessel response taking into account in-vessel components. A detailed analysis of the vacuum vessel response to the loss of coolant accident was performed using lumped-parameter codes COCOSYS and ASTEC. The performed analysis showed that the installed plasma vessel venting system prevents overpressure of PV in case of 40 mm diameter LOCA in “baking” mode. The performed analysis revealed differences in heat transfer modelling implemented in ASTEC and COCOSYS computer codes, which require further investigation to justify the correct approach for application to fusion facilities.

  17. 50 CFR 660.305 - Vessel identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Vessel identification. 660.305 Section 660.305 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Fisheries § 660.305 Vessel identification. (a) Display. The operator of a vessel that is over 25 ft (7.6 m...

  18. 50 CFR 660.704 - Vessel identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Vessel identification. 660.704 Section 660.704 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 660.704 Vessel identification. (a) General. This section only applies to commercial fishing vessels...

  19. 50 CFR 660.504 - Vessel identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Vessel identification. 660.504 Section 660.504 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 660.504 Vessel identification. (a) Official number. Each fishing vessel subject to this subpart must...

  20. 50 CFR 665.16 - Vessel identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Vessel identification. 665.16 Section 665... identification. (a) Applicability. Each fishing vessel subject to this part, except those identified in paragraph (e) of this section, must be marked for identification purposes, as follows: (1) A vessel that is...

  1. A protection system for the JET ITER-like wall based on imaging diagnostics.

    Science.gov (United States)

    Arnoux, G; Devaux, S; Alves, D; Balboa, I; Balorin, C; Balshaw, N; Beldishevski, M; Carvalho, P; Clever, M; Cramp, S; de Pablos, J-L; de la Cal, E; Falie, D; Garcia-Sanchez, P; Felton, R; Gervaise, V; Goodyear, A; Horton, A; Jachmich, S; Huber, A; Jouve, M; Kinna, D; Kruezi, U; Manzanares, A; Martin, V; McCullen, P; Moncada, V; Obrejan, K; Patel, K; Lomas, P J; Neto, A; Rimini, F; Ruset, C; Schweer, B; Sergienko, G; Sieglin, B; Soleto, A; Stamp, M; Stephen, A; Thomas, P D; Valcárcel, D F; Williams, J; Wilson, J; Zastrow, K-D

    2012-10-01

    The new JET ITER-like wall (made of beryllium and tungsten) is more fragile than the former carbon fiber composite wall and requires active protection to prevent excessive heat loads on the plasma facing components (PFC). Analog CCD cameras operating in the near infrared wavelength are used to measure surface temperature of the PFCs. Region of interest (ROI) analysis is performed in real time and the maximum temperature measured in each ROI is sent to the vessel thermal map. The protection of the ITER-like wall system started in October 2011 and has already successfully led to a safe landing of the plasma when hot spots were observed on the Be main chamber PFCs. Divertor protection is more of a challenge due to dust deposits that often generate false hot spots. In this contribution we describe the camera, data capture and real time processing systems. We discuss the calibration strategy for the temperature measurements with cross validation with thermal IR cameras and bi-color pyrometers. Most importantly, we demonstrate that a protection system based on CCD cameras can work and show examples of hot spot detections that stop the plasma pulse. The limits of such a design and the associated constraints on the operations are also presented.

  2. A protection system for the JET ITER-like wall based on imaging diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Arnoux, G.; Balboa, I.; Balshaw, N.; Beldishevski, M.; Cramp, S.; Felton, R.; Goodyear, A.; Horton, A.; Kinna, D.; McCullen, P.; Obrejan, K.; Patel, K.; Lomas, P. J.; Rimini, F.; Stamp, M.; Stephen, A.; Thomas, P. D.; Williams, J.; Wilson, J.; Zastrow, K.-D. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); and others

    2012-10-15

    The new JET ITER-like wall (made of beryllium and tungsten) is more fragile than the former carbon fiber composite wall and requires active protection to prevent excessive heat loads on the plasma facing components (PFC). Analog CCD cameras operating in the near infrared wavelength are used to measure surface temperature of the PFCs. Region of interest (ROI) analysis is performed in real time and the maximum temperature measured in each ROI is sent to the vessel thermal map. The protection of the ITER-like wall system started in October 2011 and has already successfully led to a safe landing of the plasma when hot spots were observed on the Be main chamber PFCs. Divertor protection is more of a challenge due to dust deposits that often generate false hot spots. In this contribution we describe the camera, data capture and real time processing systems. We discuss the calibration strategy for the temperature measurements with cross validation with thermal IR cameras and bi-color pyrometers. Most importantly, we demonstrate that a protection system based on CCD cameras can work and show examples of hot spot detections that stop the plasma pulse. The limits of such a design and the associated constraints on the operations are also presented.

  3. Improvement of Plasma Performance with Lithium Wall Conditioning in Aditya Tokamak

    Science.gov (United States)

    B. Chowdhuri, M.; Manchanda, R.; Ghosh, J.; B. Bhatt, S.; Ajai, Kumar; K. Das, B.; A. Jadeja, K.; A. Raijada, P.; Manoj, Kumar; Banerjee, S.; Nilam, Ramaiya; Aniruddh, Mali; Ketan, M. Patel; Vinay, Kumar; Vasu, P.; Bhattacharyay, R.; L. Tanna, R.; Y. Shankara, Joisa; K. Atrey, P.; V. S. Rao, C.; Chenna Reddy, D.; K. Chattopadhyay, P.; Jha, R.; C. Saxena, Y.; Aditya Team

    2013-02-01

    Lithiumization of the vacuum vessel wall of the Aditya tokamak using a lithium rod exposed to glow discharge cleaning plasma has been done to understand its effect on plasma performance. After the Li-coating, an increment of ~100 eV in plasma electron temperature has been observed in most of the discharges compared to discharges without Li coating, and the shot reproducibility is considerably improved. Detailed studies of impurity behaviour and hydrogen recycling are made in the Li coated discharges by observing spectral lines of hydrogen, carbon, and oxygen in the visible region using optical fiber, an interference filter, and PMT based systems. A large reduction in O I signal (up to ~40% to 50%) and a 20% to 30% decrease of Hα signal indicate significant reduction of wall recycling. Furthermore, VUV emissions from O V and Fe XV monitored by a grazing incidence monochromator also show the reduction. Lower Fe XV emission indicates the declined impurity penetration to the core plasma in the Li coated discharges. Significant increase of the particle and energy confinement times and the reduction of Zeff of the plasma certainly indicate the improved plasma parameters in the Aditya tokamak after lithium wall conditioning.

  4. Integrating Building Functions into Massive External Walls

    Directory of Open Access Journals (Sweden)

    Ahmed Hisham Hafez

    2017-11-01

    Full Text Available Well into the twentieth century, brick and stone were the materials used. Bricklaying and stonemasonry were the construction technologies employed for the exterior walls of virtually all major structures. However, with the rise in quality of life, the massive walls alone became incapable of fulfilling all the developed needs. Adjacent systems and layers had then to be attached to the massive layer. Nowadays, the external wall is usually composed of a layered construction. Each external wall function is usually represented by a separate layer or system. The massive layer of the wall is usually responsible for the load-bearing function. Traditional massive external walls vary in terms of their external appearance, their composition and attached layers. However, their design and construction process is usually a repeated process. It is a linear process where each discipline is concerned with a separate layer or system. These disciplines usually take their tasks away and bring them back to be re-integrated in a layered manner. New massive technologies with additional function have recently become available. Such technologies can provide the external wall with other functions in addition to its load-bearing function. The purpose of this research is to map the changes required to the traditional design and construction process when massive technologies with additional function are applied in external walls. Moreover, the research aims at assessing the performance of massive solutions with additional function when compared to traditional solutions in two different contexts, the Netherlands and Egypt. Through the analysis of different additional function technologies in external walls, a guidance scheme for different stakeholders is generated. It shows the expected process changes as related to the product level and customization level. Moreover, the research concludes that the performance of additional insulating technologies, and specifically

  5. Development and plasticity of meningeal lymphatic vessels.

    Science.gov (United States)

    Antila, Salli; Karaman, Sinem; Nurmi, Harri; Airavaara, Mikko; Voutilainen, Merja H; Mathivet, Thomas; Chilov, Dmitri; Li, Zhilin; Koppinen, Tapani; Park, Jun-Hee; Fang, Shentong; Aspelund, Aleksanteri; Saarma, Mart; Eichmann, Anne; Thomas, Jean-Léon; Alitalo, Kari

    2017-11-15

    The recent discovery of meningeal lymphatic vessels (LVs) has raised interest in their possible involvement in neuropathological processes, yet little is known about their development or maintenance. We show here that meningeal LVs develop postnatally, appearing first around the foramina in the basal parts of the skull and spinal canal, sprouting along the blood vessels and cranial and spinal nerves to various parts of the meninges surrounding the central nervous system (CNS). VEGF-C, expressed mainly in vascular smooth muscle cells, and VEGFR3 in lymphatic endothelial cells were essential for their development, whereas VEGF-D deletion had no effect. Surprisingly, in adult mice, the LVs showed regression after VEGF-C or VEGFR3 deletion, administration of the tyrosine kinase inhibitor sunitinib, or expression of VEGF-C/D trap, which also compromised the lymphatic drainage function. Conversely, an excess of VEGF-C induced meningeal lymphangiogenesis. The plasticity and regenerative potential of meningeal LVs should allow manipulation of cerebrospinal fluid drainage and neuropathological processes in the CNS. © 2017 Antila et al.

  6. A continuum damage analysis of hydrogen attack in a 2.25Cr-1Mo pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Burg, M.W.D. van der; Giessen, E. van der [Technische Univ. Delft (Netherlands). Dept. of Mechanical Engineering; Tvergaard, V. [Danmarks Tekniske Hoejskole, Lyngby (Denmark). Dept. of Solid Mechanics

    1998-01-30

    A micromechanically based continuum damage model is presented to analyze the stress, temperature and hydrogen pressure dependent material degradation process termed hydrogen attack, inside a pressure vessel. Hydrogen attack (HA) is the damage process of grain boundary facets due to a chemical reaction of carbides with hydrogen, thus forming cavities with high pressure methane gas. Driven by the methane gas pressure, the cavities grow, while remote tensile stresses can significantly enhance the cavitation rate. The damage model gives the strain-rate and damage rate as a function of the temperature, hydrogen pressure and applied stresses. The model is applied to study HA in a vessel wall, where nonuniform distributions lf hydrogen pressure, temperature and stresses result in a nonuniform damage distribution over the vessel wall. Stresses inside the vessel wall first tend to accelerate and later decelerate the cavitation rate significantly. Numerical studies for different material parameters and different stress conditions demonstrate the HA process inside a vessel in time. Also, the lifetime of the pressure vessel is determined. The analyses underline that the general applicability of the Nelson curve is questionable. (orig.) 30 refs.

  7. Magnetic confinement of repelling Bloch walls

    Science.gov (United States)

    Magyari, E.; Thomas, H.

    1992-01-01

    In a ferromagnet with orthorhombic magneto-crystalline anisotropy, two repelling 180° domain walls (π kinks) can be pushed together to form a 360° domain wall (2π kink) by applying a magnetic field in the easy direction. We show that such a magnetically confined static 360° plane domain wall with Bloch-like structure, connecting two semi-infinite domains with parallel spin orientation, is linearly stable only below a critical strength Bc of the applied field. At B = Bc it becomes unstable with respect to a mode with spin component along the hard direction.

  8. Type VII secretion-mycobacteria show the way.

    NARCIS (Netherlands)

    Abdallah, A.M.; Gey van Pittius, N.C.; Champion, P.A.; Cox, J.; Luirink, S.; Vandenbroucke-Grauls, C.M.J.E.; Appelmelk, B.J.; Bitter, W.

    2007-01-01

    Recent evidence shows that mycobacteria have developed novel and specialized secretion systems for the transport of extracellular proteins across their hydrophobic, and highly impermeable, cell wall. Strikingly, mycobacterial genomes encode up to five of these transport systems. Two of these

  9. Creating universes with thick walls

    CERN Document Server

    Ulvestad, Andrew

    2012-01-01

    We study the dynamics of a spherically symmetric false vacuum bubble embedded in a true vacuum region separated by a "thick wall", which is generated by a scalar field in a quartic potential. We study the "Farhi-Guth-Guven" (FGG) quantum tunneling process by constructing numerical solutions relevant to this process. The ADM mass of the spacetime is calculated, and we show that there is a lower bound that is a significant fraction of the scalar field mass. We argue that the zero mass solutions used to by some to argue against the physicality of the FGG process are artifacts of the thin wall approximation used in earlier work. We argue that the zero mass solutions should not be used to question the viability of the FGG process.

  10. Integrating Multiple Autonomous Underwater Vessels, Surface Vessels and Aircraft into Oceanographic Research Vessel Operations

    Science.gov (United States)

    McGillivary, P. A.; Borges de Sousa, J.; Martins, R.; Rajan, K.

    2012-12-01

    Autonomous platforms are increasingly used as components of Integrated Ocean Observing Systems and oceanographic research cruises. Systems deployed can include gliders or propeller-driven autonomous underwater vessels (AUVs), autonomous surface vessels (ASVs), and unmanned aircraft systems (UAS). Prior field campaigns have demonstrated successful communication, sensor data fusion and visualization for studies using gliders and AUVs. However, additional requirements exist for incorporating ASVs and UASs into ship operations. For these systems to be optimally integrated into research vessel data management and operational planning systems involves addressing three key issues: real-time field data availability, platform coordination, and data archiving for later analysis. A fleet of AUVs, ASVs and UAS deployed from a research vessel is best operated as a system integrated with the ship, provided communications among them can be sustained. For this purpose, Disruptive Tolerant Networking (DTN) software protocols for operation in communication-challenged environments help ensure reliable high-bandwidth communications. Additionally, system components need to have considerable onboard autonomy, namely adaptive sampling capabilities using their own onboard sensor data stream analysis. We discuss Oceanographic Decision Support System (ODSS) software currently used for situational awareness and planning onshore, and in the near future event detection and response will be coordinated among multiple vehicles. Results from recent field studies from oceanographic research vessels using AUVs, ASVs and UAS, including the Rapid Environmental Picture (REP-12) cruise, are presented describing methods and results for use of multi-vehicle communication and deliberative control networks, adaptive sampling with single and multiple platforms, issues relating to data management and archiving, and finally challenges that remain in addressing these technological issues. Significantly, the

  11. DETERMINATION OF LIQUID FILM THICKNESS FOLLOWING DRAINING OF CONTACTORS, VESSELS, AND PIPES IN THE MCU PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M; Fernando Fondeur, F; Samuel Fink, S

    2006-06-06

    The Department of Energy (DOE) identified the caustic side solvent extraction (CSSX) process as the preferred technology to remove cesium from radioactive waste solutions at the Savannah River Site (SRS). As a result, Washington Savannah River Company (WSRC) began designing and building a Modular CSSX Unit (MCU) in the SRS tank farm to process liquid waste for an interim period until the Salt Waste Processing Facility (SWPF) begins operations. Both the solvent and the strip effluent streams could contain high concentrations of cesium which must be removed from the contactors, process tanks, and piping prior to performing contactor maintenance. When these vessels are drained, thin films or drops will remain on the equipment walls. Following draining, the vessels will be flushed with water and drained to remove the flush water. The draining reduces the cesium concentration in the vessels by reducing the volume of cesium-containing material. The flushing, and subsequent draining, reduces the cesium in the vessels by diluting the cesium that remains in the film or drops on the vessel walls. MCU personnel requested that Savannah River National Laboratory (SRNL) researchers conduct a literature search to identify models to calculate the thickness of the liquid films remaining in the contactors, process tanks, and piping following draining of salt solution, solvent, and strip solution. The conclusions from this work are: (1) The predicted film thickness of the strip effluent is 0.010 mm on vertical walls, 0.57 mm on horizontal walls and 0.081 mm in horizontal pipes. (2) The predicted film thickness of the salt solution is 0.015 mm on vertical walls, 0.74 mm on horizontal walls, and 0.106 mm in horizontal pipes. (3) The predicted film thickness of the solvent is 0.022 mm on vertical walls, 0.91 mm on horizontal walls, and 0.13 mm in horizontal pipes. (4) The calculated film volume following draining is: (a) Salt solution receipt tank--1.6 gallons; (b) Salt solution feed

  12. Correlation between spin structure oscillations and domain wall velocities

    Science.gov (United States)

    Bisig, André; Stärk, Martin; Mawass, Mohamad-Assaad; Moutafis, Christoforos; Rhensius, Jan; Heidler, Jakoba; Büttner, Felix; Noske, Matthias; Weigand, Markus; Eisebitt, Stefan; Tyliszczak, Tolek; van Waeyenberge, Bartel; Stoll, Hermann; Schütz, Gisela; Kläui, Mathias

    2013-08-01

    Magnetic sensing and logic devices based on the motion of magnetic domain walls rely on the precise and deterministic control of the position and the velocity of individual magnetic domain walls in curved nanowires. Varying domain wall velocities have been predicted to result from intrinsic effects such as oscillating domain wall spin structure transformations and extrinsic pinning due to imperfections. Here we use direct dynamic imaging of the nanoscale spin structure that allows us for the first time to directly check these predictions. We find a new regime of oscillating domain wall motion even below the Walker breakdown correlated with periodic spin structure changes. We show that the extrinsic pinning from imperfections in the nanowire only affects slow domain walls and we identify the magnetostatic energy, which scales with the domain wall velocity, as the energy reservoir for the domain wall to overcome the local pinning potential landscape.

  13. Polarization control at spin-driven ferroelectric domain walls.

    Science.gov (United States)

    Leo, Naëmi; Bergman, Anders; Cano, Andres; Poudel, Narayan; Lorenz, Bernd; Fiebig, Manfred; Meier, Dennis

    2015-04-14

    Unusual electronic states arise at ferroelectric domain walls due to the local symmetry reduction, strain gradients and electrostatics. This particularly applies to improper ferroelectrics, where the polarization is induced by a structural or magnetic order parameter. Because of the subordinate nature of the polarization, the rigid mechanical and electrostatic boundary conditions that constrain domain walls in proper ferroics are lifted. Here we show that spin-driven ferroelectricity promotes the emergence of charged domain walls. This provides new degrees of flexibility for controlling domain-wall charges in a deterministic and reversible process. We create and position a domain wall by an electric field in Mn0.95Co0.05WO4. With a magnetic field we then rotate the polarization and convert neutral into charged domain walls, while its magnetic properties peg the wall to its location. Using atomistic Landau-Lifshitz-Gilbert simulations we quantify the polarization changes across the two wall types and highlight their general occurrence.

  14. Cutaneous Small Vessel Vasculitis Accompanied by Pustulosis Palmaris et Plantaris

    Directory of Open Access Journals (Sweden)

    Motoko Kosaka

    2012-03-01

    Full Text Available We present the case of a 64-year-old woman who has suffered from pustulosis palmaris et plantaris for 10 years. At the first examination, many erythematous lesions with purpura, blood crusts, and blisters were present in the lower legs and dorsum of the feet. Painful swelling in the sternal region and dorsal pain were also noted. Elevation of the CRP and myogenic enzyme levels, and liver and renal dysfunctions were noted on blood testing. Histopathologically, leukocytoclastic vasculitis was noted in small blood vessels in the whole dermal layers, and deposition of IgM and C3 in the vascular wall was detected by the direct immunofluorescence techniques. Based on these findings, cutaneous small vessel vasculitis was diagnosed. Because the patient complained of a toothache during the clinical course, an X-ray examination was performed. On pantomography, a radicular cyst and apical periodontitis were noted. The tooth symptoms changed with exacerbation and remission of the skin symptoms. These findings indicate that odontogenic infection is very likely to be a cause of cutaneous small vessel vasculitis in a manner similar to pustulosis palmaris et plantaris.

  15. KETERASINGAN DALAM FILM WALL-E

    Directory of Open Access Journals (Sweden)

    Rahmadya Putra Nugraha

    2017-05-01

    Full Text Available Modern society nowadays technological advances at first create efficiency in human life. Further development of the technology thus drown human in a routine and automation of work created. The State is to be one of the causes of man separated from fellow or the outside world and eventually experiencing alienation. The movie as a mass media function to obtain the movie and entertainment can be informative or educative function is contained, even persuasive. The purpose of this research was conducted to find out the alienation in the movie Wall E. The concepts used to analyze the movie Wall E this is communication, movie, and alienation. The concept of alienation of human alienation from covering its own products of human alienation from its activities, the human alienation from nature of his humanity and human alienation from each other. Paradigm used is a critical paradigm with type a descriptive research with qualitative approach. The method used is the analysis of semiotics Roland Barthes to interpretation the scope of social alienation and fellow humans in the movie.This writing research results found that alienation of humans with other humans influenced the development of the technology and how the human it self represented of technology, not from our fellow human beings. Masyarakat modern saat ini kemajuan teknologi pada awalnya membuat efisiensi dalam kehidupan manusia. Perkembangan selanjutnya teknologi justru menenggelamkan manusia dalam suatu rutinitas dan otomatisasi kerja yang diciptakan. Keadaan itulah yang menjadi salah satu penyebab manusia terpisah dari sesama atau dunia luar dan akhirnya mengalami keterasingan. Film sebagai media massa berfungsi untuk memperoleh hiburan dan dalam film dapat terkandung fungsi informatif maupun edukatif, bahkan persuasif. Tujuan Penelitian ini dilakukan untuk mengetahui Keterasingan dalam film Wall E. Konsep-konsep yang digunakan untuk menganalisis film Wall E ini adalah komunikasi, film, dan

  16. Computed tomography angiographic study of internal mammary perforators and their use as recipient vessels for free tissue transfer in breast reconstruction

    Directory of Open Access Journals (Sweden)

    Aditya V Kanoi

    2017-01-01

    Full Text Available Context: The internal mammary artery perforator vessels (IMPV as a recipient in free flap breast reconstruction offer advantages over the more commonly used thoracodorsal vessels and the internal mammary vessels (IMV. Aims: This study was designed to assess the anatomical consistency of the IMPV and the suitability of these vessels for use as recipients in free flap breast reconstruction. Patients and Methods: Data from ten randomly selected female patients who did not have any chest wall or breast pathology but had undergone a computed tomography angiography (CTA for unrelated diagnostic reasons from April 2013 to October 2013 were analysed. Retrospective data of seven patients who had undergone mastectomy for breast cancer and had been primarily reconstructed with a deep inferior epigastric artery perforator free flap transfer using the IMPV as recipient vessels were studied. Results: The CTA findings showed that the internal mammary perforator was consistently present in all cases bilaterally. In all cases, the dominant perforator arose from the upper four intercostal spaces (ICS with the majority (55% arising from the 2nd ICS. The mean distance of the perforators from the sternal border at the level of pectoralis muscle surface on the right side was 1.86 cm (range: 0.9–2.5 cm with a mode value of 1.9 cm. On the left side, a mean of 1.77 cm (range: 1.5–2.1 cm and a mode value of 1.7 cm were observed. Mean perforator artery diameters on the right and left sides were 2.2 mm and 2.4 mm, respectively. Conclusions: Though the internal mammary perforators are anatomically consistent, their use as recipients in free tissue transfer for breast reconstruction eventually rests on multiple variables.

  17. Arterial Wall Properties and Womersley Flow in Fabry Disease

    Directory of Open Access Journals (Sweden)

    Dimitriadis Emilios

    2002-01-01

    Full Text Available Abstract Background Fabry disease is an X-linked recessive lysosomal storage disease resulting in the cellular accumulation of globotriaosylceramide particularly globotriaosylceramide. The disease is characterized by a dilated vasculopathy with arterial ectasia in muscular arteries and arterioles. Previous venous plethysomographic studies suggest enhanced endothelium-dependent vasodilation in Fabry disease indicating a functional abnormality of resistance vessels. Methods We examined the mechanical properties of the radial artery in Fabry disease, a typical fibro-muscular artery. Eight control subjects and seven patients with Fabry disease had a right brachial arterial line placed allowing real time recording of intra-arterial blood pressure. Real time B-mode ultrasound recordings of the right radial artery were obtained simultaneously allowing calculation of the vessel wall internal and external diameter, the incremental Young's modulus and arterial wall thickness. By simultaneously measurement of the distal index finger-pulse oximetry the pulse wave speed was calculated. From the wave speed and the internal radial artery diameter the volume flow was calculated by Womersley analysis following truncation of the late diastolic phase. Results No significant difference was found between Fabry patients and controls for internal or external arterial diameters, the incremental Young's modulus, the arterial wall thickness, the pulse wave speed and the basal radial artery blood flow. Further, no significant difference was found for the radial artery blood flow in response to intra-arterial acetylcholine or sodium nitroprusside. Both drugs however, elevated the mean arterial flow. Conclusions The current study suggests that no structural or mechanical abnormality exists in the vessel wall of fibro-muscular arteries in Fabry disease. This may indicate that a functional abnormality downstream to the conductance vessels is the dominant feature in

  18. Mapping the longitudinal wall stiffness heterogeneities within intact canine aortas using Pulse Wave Imaging (PWI) ex vivo.

    Science.gov (United States)

    Shahmirzadi, Danial; Narayanan, Prathyush; Li, Ronny X; Qaqish, William W; Konofagou, Elisa E

    2013-07-26

    The aortic stiffness has been found to be a useful independent indicator of several cardiovascular diseases such as hypertension and aneurysms. Existing methods to estimate the aortic stiffness are either invasive, e.g. catheterization, or yield average global measurements which could be inaccurate, e.g., tonometry. Alternatively, the aortic pulse wave velocity (PWV) has been shown to be a reliable marker for estimating the wall stiffness based on the Moens-Korteweg (M-K) formulation. Pulse Wave Imaging (PWI) is a relatively new, ultrasound-based imaging method for noninvasive and regional estimation of PWV. The present study aims at showing the application of PWI in obtaining localized wall mechanical properties by making PWV measurements on several adjacent locations along the ascending thoracic to the suprarenal abdominal aortic trunk in its intact vessel form. The PWV estimates were used to calculate the regional wall modulus based on the M-K relationship and were compared against conventional mechanical testing. The findings indicated that for the anisotropic aortic wall, the PWI estimates of the modulus are smaller than the circumferential modulus by an average of -32.22% and larger than the longitudinal modulus by an average of 25.83%. Ongoing work is focused on the in vivo applications of PWI in normal and pathological aortas with future implications in the clinical applications of the technique. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Expression of the growth factor progranulin in endothelial cells influences growth and development of blood vessels: a novel mouse model.

    Science.gov (United States)

    Toh, Huishi; Cao, Mingju; Daniels, Eugene; Bateman, Andrew

    2013-01-01

    Progranulin is a secreted glycoprotein that regulates cell proliferation, migration and survival. It has roles in development, tumorigenesis, wound healing, neurodegeneration and inflammation. Endothelia in tumors, wounds and placenta express elevated levels of progranulin. In culture, progranulin activates endothelial proliferation and migration. This suggested that progranulin might regulate angiogenesis. It was, however, unclear how elevated endothelial progranulin levels influence vascular growth in vivo. To address this issue, we generated mice with progranulin expression targeted specifically to developing endothelial cells using a Tie2-promoter/enhancer construct. Three Tie2-Grn mouse lines were generated with varying Tie2-Grn copy number, and were called GrnLo, GrnMid, and GrnHi. All three lines showed increased mortality that correlates with Tie2-Grn copy number, with greatest mortality and lowest germline transmission in the GrnHi line. Death of the transgenic animals occurred around birth, and continued for three days after birth. Those that survived beyond day 3 survived into adulthood. Transgenic neonates that died showed vascular abnormalities of varying severity. Some exhibited bleeding into body cavities such as the pericardial space. Smaller localized hemorrhages were seen in many organs. Blood vessels were often dilated and thin-walled. To establish the development of these abnormalities, we examined mice at early (E10.5-14.5) and later (E15.5-17.5) developmental phases. Early events during vasculogenesis appear unaffected by Tie2-Grn as apparently normal primary vasculature had been established at E10.5. The earliest onset of vascular abnormality was at E15.5, with focal cerebral hemorrhage and enlarged vessels in various organs. Aberrant Tie2-Grn positive vessels showed thinning of the basement membrane and reduced investiture with mural cells. We conclude that progranulin promotes exaggerated vessel growth in vivo, with subsequent effects in

  20. Recovery after abdominal wall reconstruction.

    Science.gov (United States)

    Jensen, Kristian Kiim

    2017-03-01

    implementation of the pathway. The enhanced recovery after surgery pathway included preoperative high-dose steroid, daily assessment of revised discharge criteria and an aggressive approach to restore bowel function (chewing gum and enema on postoperative day two). Patients who followed the enhanced recovery after surgery pathway reported low scores of pain, nausea and fatigue, and were discharged significantly faster than patients in the control group. A non-significant increase in postoperative readmissions and reoperations was observed after the introduction of the enhanced recovery after surgery pathway. Study III and IV were prospective studies of patients undergoing abdominal wall reconstruction for giant incisional hernia, who were compared to a control group of patients with an intact abdominal wall undergoing colorectal resection for benign or low-grade malignant disease. Patients were examined within a week preoperatively and again one year postoperatively. In study III, the respiratory function and respiratory quality of life were assessed, and the results showed that patients with a giant incisional hernia had a decreased expiratory lung function (peak expiratory flow and maximal expiratory pressure) compared to the predicted values and also compared to patients in the control group. Both parameters increased significantly after abdominal wall reconstruction, while no other significant changes were found in objective or subjective measures at one-year follow-up in both groups of patients. Lastly, study IV examined the abdominal wall- and extremity function, as well as overall and disease specific quality of life. We found that patients with a giant hernia had a significantly decreased relative function of the abdominal wall compared to patients with an intact abdominal wall, and that this deficit was offset at one-year follow-up. Patients in the control group showed a postoperative decrease in abdominal wall function, while no changes were found in extremity function

  1. Radial Corrugations of Multi-Walled Carbon Nanotubes Driven by Inter-Wall Nonbonding Interactions

    Directory of Open Access Journals (Sweden)

    Huang Xu

    2011-01-01

    Full Text Available Abstract We perform large-scale quasi-continuum simulations to determine the stable cross-sectional configurations of free-standing multi-walled carbon nanotubes (MWCNTs. We show that at an inter-wall spacing larger than the equilibrium distance set by the inter-wall van der Waals (vdW interactions, the initial circular cross-sections of the MWCNTs are transformed into symmetric polygonal shapes or asymmetric water-drop-like shapes. Our simulations also show that removing several innermost walls causes even more drastic cross-sectional polygonization of the MWCNTs. The predicted cross-sectional configurations agree with prior experimental observations. We attribute the radial corrugations to the compressive stresses induced by the excessive inter-wall vdW energy release of the MWCNTs. The stable cross-sectional configurations provide fundamental guidance to the design of single MWCNT-based devices and shed lights on the mechanical control of electrical properties.

  2. Shock Tunnel Tests of Arched Wall Panels

    Science.gov (United States)

    1974-07-01

    Post-test photographs of this test are given in Figures A-3 A and B. Figure A-3 A shows the amount of debris which landed in the casement a...spreading debris to 80 feet (the far wall of the casement ) as shown in the post-test photograph in Figure A-7. Displacement gauge data...10 psi) . The wall failed atastrophically, with debris scattered throughout the tunnel and casement area. Approxi- mately 10 percent

  3. Sailing Vessel Routing Considering Safety Zone and Penalty Time for Altering Course

    Directory of Open Access Journals (Sweden)

    Marcin Zyczkowski

    2017-06-01

    Full Text Available In this paper we introduce new model for simulation sea vessel routing. Besides a vessel types (polar diagram and weather forecast, travel security and the number of maneuvers are considered. Based on these data both the minimal travelling costs and the minimal processing time are found for different vessels and different routes. To test our model the applications SailingAssistance wad improved. The obtained results shows that we can obtain quite acceptable results.

  4. Vessel-Fibre Ratio, Specific Gravity And Durability Of Four Ghanaian ...

    African Journals Online (AJOL)

    While the timbers ex-hibit major hardwood cell-types (e.g. vessels, fibres and parenchyma), intra-stem variability ex-ists with more vessels and greater V-F ratios at the crowns and in sapwoods than at the butts and in heartwoods, unlike for fibres. Inter-specific variation also shows A. toxicaria has the greatest vessel content ...

  5. The influence of selected containment structures on debris dispersal and transport following high pressure melt ejection from the reactor vessel

    Energy Technology Data Exchange (ETDEWEB)

    Pilch, M.; Tarbell, W.W.; Brockmann, J.E.

    1988-09-01

    High pressure expulsion of molten core debris from the reactor pressure vessel may result in dispersal of the debris from the reactor cavity. In most plants, the cavity exits into the containment such that the debris impinges on structures. Retention of the debris on the structures may affect the further transport of the debris throughout the containment. Two tests were done with scaled structural shapes placed at the exit of 1:10 linear scale models of the Zion cavity. The results show that the debris does not adhere significantly to structures. The lack of retention is attributed to splashing from the surface and reentrainment in the gas flowing over the surface. These processes are shown to be applicable to reactor scale. A third experiment was done to simulate the annular gap between the reactor vessel and cavity wall. Debris collection showed that the fraction of debris exiting through the gap was greater than the gap-to-total flow area ratio. Film records indicate that dispersal was primarily by entrainment of the molten debris in the cavity. 29 refs., 36 figs., 11 tabs.

  6. Young capillary vessels rejuvenate aged pancreatic islets

    Science.gov (United States)

    Almaça, Joana; Molina, Judith; Arrojo e Drigo, Rafael; Abdulreda, Midhat H.; Jeon, Won Bae; Berggren, Per-Olof; Caicedo, Alejandro; Nam, Hong Gil

    2014-01-01

    Pancreatic islets secrete hormones that play a key role in regulating blood glucose levels (glycemia). Age-dependent impairment of islet function and concomitant dysregulation of glycemia are major health threats in aged populations. However, the major causes of the age-dependent decline of islet function are still disputed. Here we demonstrate that aging of pancreatic islets in mice and humans is notably associated with inflammation and fibrosis of islet blood vessels but does not affect glucose sensing and the insulin secretory capacity of islet beta cells. Accordingly, when transplanted into the anterior chamber of the eye of young mice with diabetes, islets from old mice are revascularized with healthy blood vessels, show strong islet cell proliferation, and fully restore control of glycemia. Our results indicate that beta cell function does not decline with age and suggest that islet function is threatened by an age-dependent impairment of islet vascular function. Strategies to mitigate age-dependent dysregulation in glycemia should therefore target systemic and/or local inflammation and fibrosis of the aged islet vasculature. PMID:25404292

  7. [Study on distribution and drainage of lymphatic vessels of tongue].

    Science.gov (United States)

    Han, Xin-guang; Li, Jin-rong; Pi, Xin

    2005-10-01

    To investigate the distribution and drainage of lymphatic vessels of tongue, and to provide anatomical evidence for treatment of tongue cancer. Indirect lymphatic injection was employed, combined with clearing method with winter green oil and corrosive cast technique, to study the distribution of lymphatic vessels of tongue. Anatomical methods were used to detect the sentinel lymph nodes in different region of tongue. The lymphatic vessels of dorsal mucosa composed of lymphocapillary vessels and anstomosing side branches were present by superficial and deep capillary networks. The distribution of lymphatic networks extend from tip to base and from one board to another, and was not influenced by the sulcus tenninalis and median lingual sulcus. Lymphatic vessels in the muscular portion communicated with lymphocapillary network of dorsal and ventral mucosa, which made the lymphatic vessels of tongue to be an integrity network structure. These characters of distribution influenced the lymphatic drainage of tongue. The results showed principal sentinel lymph nodes (SLNs) for anterior part of tongue were submental lymph nodes, submandibular lymph nodes and juguloomohyoid lymph nodes, for lateral part and middle part of tongue were submandibular lymph nodes, jugulodigastric lymph nodes and thyroid lymph nodes, and for root part of tongue were jugulodigastric lymph nodes. SLNs for every injection region were all presented at bilatral neck, but the frequency of stained SLNs at homolateral neck was more than that at contralateral neck. The lymphatic vessels of tongue arranged like a network, which made the lymphatic drainage at various ways and made the distribution of sentinel lymph nodes to be bilateral and dispersive.

  8. Doppler sonography of extracranial and intracranial vessels in patients with thrombotic stroke

    Directory of Open Access Journals (Sweden)

    Farhad Iranmanesh

    2006-12-01

    Full Text Available INTRODUCTION: The results of intracranial and extracranial vessel color Doppler sonography, which is now an inseparable part of patient evaluation, vary in different studies. The objective of this study was to evaluate the pattern of vascular involvement in thrombotic stroke and its relationship with risk factors of stroke. METHODS: One-hundred patients (45 males and 55 females with thrombotic stroke underwent transcranial sonography and color Doppler sonography of extracranial vessels. The pattern of vascular involvement was analyzed. The risk factors of stroke were also evaluated. RESULTS: Forty-seven percent of the studied individuals had some variations in their color Doppler sonography of extracranial vessels, 27% had changes in the intracranial vessels and 26% showed changes in both. The most frequently involved vessels among the intracranial and extracranial vessels were the middle cerebral artery and the internal carotid artery, respectively. The pattern of vascular involvement was unrelated to hypertension, cigarette smoking, diabetes mellitus, dyslipidemia or history of ischemic heart disease. Extracranial involvement in patients with positive history of MI was more prevalent than in those without such history. CONCLUSIONS: Extracranial vessel involvement in thrombotic stroke was found to be more prevalent than intracranial vessel involvement in the city of Rafsanjan; however, intracranial vessel involvement was more prevalent than in western countries. KEY WORDS: Thrombotic stroke, color Doppler sonography, intracranial vessels, extracranial, cerebrovascular risk factors

  9. Robust vessel detection and segmentation in ultrasound images by a data-driven approach

    Science.gov (United States)

    Guo, Ping; Wang, Qiang; Wang, Xiaotao; Hao, Zhihui; Xu, Kuanhong; Ren, Haibing; Kim, Jung Bae; Hwang, Youngkyoo

    2014-03-01

    This paper presents a learning based vessel detection and segmentation method in real-patient ultrasound (US) liver images. We aim at detecting multiple shaped vessels robustly and automatically, including vessels with weak and ambiguous boundaries. Firstly, vessel candidate regions are detected by a data-driven approach. Multi-channel vessel enhancement maps with complement performances are generated and aggregated under a Conditional Random Field (CRF) framework. Vessel candidates are obtained by thresholding the saliency map. Secondly, regional features are extracted and the probability of each region being a vessel is modeled by random forest regression. Finally, a fast levelset method is developed to refine vessel boundaries. Experiments have been carried out on an US liver dataset with 98 patients. The dataset contains both normal and abnormal liver images. The proposed method in this paper is compared with a traditional Hessian based method, and the average precision is promoted by 56 percents and 7.8 percents for vessel detection and classification, respectively. This improvement shows that our method is more robust to noise, therefore has a better performance than the Hessian based method for the detection of vessels with weak and ambiguous boundaries.

  10. MR evaluation of vessel size imaging of human gliomas: Validation by histopathology.

    Science.gov (United States)

    Kellner, Elias; Breyer, Tobias; Gall, Peter; Müller, Klaus; Trippel, Michael; Staszewski, Ori; Stein, Florian; Saborowski, Olaf; Dyakova, Olga; Urbach, Horst; Kiselev, Valerij G; Mader, Irina

    2015-10-01

    To compare the vessel size and the cerebral blood volume in human gliomas with histopathology. Vessel size imaging (VSI) is a dynamic susceptibility contrast method for the assessment of the vessel size in normal and pathological tissue. Previous publications in rodents showed a satisfactory conformity with the vessel size derived from histopathology. To assess the clinical value, further, the progression-free interval was determined and correlated. Twenty-five gliomas (WHO grade °II [n = 10], °III [n = 3], °IV [n = 12]) were prospectively included and received a stereotaxic biopsy after VSI. The vessel size and the cerebral blood volume (CBV) were calculated in regions of interest at the tumor edge and correlated with the vessel size measured by histopathology. Both VSI and CBV showed a good correlation with the vessel size in histopathology (up to r = 0.84, P histopathology is in good accordance with the animal studies. The overestimation of small capillary sizes is also known from the animal trials. Vessel size and CBV showed similar results, both for the correlation with the histopathological vessel size and the progression-free interval. © 2014 Wiley Periodicals, Inc.

  11. Ideal Magnetohydrodynamics Stability Spectrum with a Resistive Wall

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S. P. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Jardin, S. C. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    2008-05-01

    We show that the eigenvalue equations describing a cylindrical ideal magnetophydrodynamicsw (MHD) plasma interacting with a thin resistive wall can be put into the standard mathematical form: Α•χ = λΒ• χ. This is accomplished by using a finite element basis for the plasma, and by adding an extra degree of freedom corresponding to the electrical current in the thin wall. The standard form allows the use of linear eigenvalue solvers, without additional interations, to compute the complete spectrum of plasma modes in the presence of a surrounding restrictive wall at arbitrary separation. We show that our method recovers standard results in the limits of (1) an infinitely resistive wall (no wall), and (2) a zero resistance wall (ideal wall).

  12. Label-Free In Vivo Imaging of Corneal Lymphatic Vessels Using Microscopic Optical Coherence Tomography.

    Science.gov (United States)

    Horstmann, Jens; Schulz-Hildebrandt, Hinnerk; Bock, Felix; Siebelmann, Sebastian; Lankenau, Eva; Hüttmann, Gereon; Steven, Philipp; Cursiefen, Claus

    2017-11-01

    Corneal neovascularization, in particular lymphangiogenesis, is a limiting factor in corneal transplant survival. Novel treatment approaches focus on (selective) inhibition and regression of lymphatic vessels. Imaging clinically invisible corneal lymphatic vessels is a prerequisite for these strategies. Using a murine model, this study investigates whether corneal lymphatic vessels can be imaged using microscopic optical coherence tomography (mOCT). Corneal neovascularization was induced by intrastromal placement of 11.0 nylon sutures in one eye of BALB/c mice. After 2 weeks, cross-sectional images and volumes of the corneas with a 0.5 mm lateral and axial field of view were acquired using a custom-built mOCT system enabling a resolution of 1 μm at a B-scan rate of 165/s. Three of the six animals received an additional intrastromal injection of India ink 24 hours before the measurement to stain the corneal lymphatic system in vivo. Immunohistochemistry using CD31 and LYVE-1 was used to validate the mOCT findings. Using mOCT, lymphatic vessels were visible as dark vessel-like structures with the lumen lacking a hyperreflective wall and mostly lacking cells. However, individual, slowly moving particles, which most likely are immune cells, occasionally could be observed inside the lumen. In lymphatic vessels of ink-stained corneas, hyperreflection and shadowing underneath was observed. Ink-filled lymphatic vessels were colocalized in consecutive corneal flat mounts of the same specimen. Corneal lymphatic vessels can be imaged using mOCT. This novel approach opens new options for noninvasive clinical imaging of corneal lymphatic vessels for diagnostic and therapeutic indications.

  13. Patients with left bundle branch block and left axis deviation show a specific left ventricular asynchrony pattern: Implications for left ventricular lead placement during CRT implantation.

    Science.gov (United States)

    Sciarra, Luigi; Golia, Paolo; Palamà, Zefferino; Scarà, Antonio; De Ruvo, Ermenegildo; Borrelli, Alessio; Martino, Anna Maria; Minati, Monia; Fagagnini, Alessandro; Tota, Claudia; De Luca, Lucia; Grieco, Domenico; Delise, Pietro; Calò, Leonardo

    2017-10-21

    Left bundle branch block (LBBB) and left axis deviation (LAD) patients may have poor response to resynchronization therapy (CRT). We sought to assess if LBBB and LAD patients show a specific pattern of mechanical asynchrony. CRT candidates with non-ischemic cardiomyopathy and LBBB were categorized as having normal QRS axis (within -30° and +90°) or LAD (within -30° and -90°). Patients underwent tissue Doppler imaging (TDI) to measure time interval between onset of QRS complex and peak systolic velocity in ejection period (Q-peak) at basal segments of septal, inferior, lateral and anterior walls, as expression of local timing of mechanical activation. Thirty patients (mean age 70.6years; 19 males) were included. Mean left ventricular ejection fraction was 0.28±0.06. Mean QRS duration was 172.5±13.9ms. Fifteen patients showed LBBB with LAD (QRS duration 173±14; EF 0.27±0.06). The other 15 patients had LBBB with a normal QRS axis (QRS duration 172±14; EF 0.29±0.05). Among patients with LAD, Q-peak interval was significantly longer at the anterior wall in comparison to each other walls (septal 201±46ms, inferior 242±58ms, lateral 267±45ms, anterior 302±50ms; p<0.0001). Conversely, in patients without LAD Q-peak interval was longer at lateral wall, when compared to each other (septal 228±65ms, inferior 250±64ms, lateral 328±98ms, anterior 291±86ms; p<0.0001). Patients with heart failure, presenting LBBB and LAD, show a specific pattern of ventricular asynchrony, with latest activation at anterior wall. This finding could affect target vessel selection during CRT procedures in these patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Effect of Viscosity Measurement Method to Simulate High Pressure Die Casting of Thin-Wall AlSi10MnMg Alloy Castings

    Science.gov (United States)

    Zhu, B. W.; Li, L. X.; Liu, X.; Zhang, L. Q.; Xu, R.

    2015-12-01

    In the present study, a rotating cylinder viscometer (RCV) was adopted to measure the viscosity of AlSi10MnMg aluminum alloy. The results show that the measured viscosity is much higher than previously reported viscosity of aluminum alloys measured by oscillation vessel viscometer. The viscosity measured by RCV was introduced into the simulation of the filling progress of high pressure die casting (HPDC) for thin-walled castings of aluminum alloy (TWCA). The simulated results match well with the experimental results indicating that the RCV is the most appropriate to use for simulations of HPDC for TWCA.

  15. Two endogenous proteins that induce cell wall extension in plants

    Science.gov (United States)

    McQueen-Mason, S.; Durachko, D. M.; Cosgrove, D. J.

    1992-01-01

    Plant cell enlargement is regulated by wall relaxation and yielding, which is thought to be catalyzed by elusive "wall-loosening" enzymes. By employing a reconstitution approach, we found that a crude protein extract from the cell walls of growing cucumber seedlings possessed the ability to induce the extension of isolated cell walls. This activity was restricted to the growing region of the stem and could induce the extension of isolated cell walls from various dicot stems and the leaves of amaryllidaceous monocots, but was less effective on grass coleoptile walls. Endogenous and reconstituted wall extension activities showed similar sensitivities to pH, metal ions, thiol reducing agents, proteases, and boiling in methanol or water. Sequential HPLC fractionation of the active wall extract revealed two proteins with molecular masses of 29 and 30 kD associated with the activity. Each protein, by itself, could induce wall extension without detectable hydrolytic breakdown of the wall. These proteins appear to mediate "acid growth" responses of isolated walls and may catalyze plant cell wall extension by a novel biochemical mechanism.

  16. Microfluidic strategy to investigate dynamics of small blood vessel function

    Science.gov (United States)

    Yasotharan, Sanjesh; Bolz, Steffen-Sebastian; Guenther, Axel

    2010-11-01

    Resistance arteries (RAs, 30-300 microns in diameter) that are located within the terminal part of the vascular tree regulate the laminar perfusion of tissue with blood, via the peripheral vascular resistance, and hence controls the systemic blood pressure. The structure of RAs is adapted to actively controlling flow resistance by dynamically changing their diameter, which is non-linearly dependent on the temporal variation of the transmural pressure, perfusion flow rate and spatiotemporal changes in the chemical environment. Increases in systemic blood pressure (hypertension) resulting from pathologic changes in the RA response represent the primary risk factor for cardiovascular diseases. We use a microfluidic strategy to investigate small blood vessels by quantifying structural variations within the arterial wall, RA outer contour and diameter over time. First, we document the artery response to vasomotor drugs that were homogeneously applied at step-wise increasing concentration. Second, we investigate the response in the presence of well-defined axial and circumferential heterogeneities. Artery per- and superfusion is discussed based on microscale PIV measurements of the fluid velocity on both sides of the arterial wall. Structural changes in the arterial wall are quantified using cross-correlation and proper orthogonal decomposition analyses of bright-field micrographs.

  17. Tensile and Fatigue Behavior of ASS304 for Cold Stretching Pressure Vessels at Cryogenic Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hoon Seok [The 5th R and D Institute, Agency for Defense Development, Daejeon (Korea, Republic of); Kim, Jae Hoon; Na, Seong Hyun [Chungnam National Univ., Daejon (Korea, Republic of); Lee, Youn Hyung [Korean Gas Safety Corporation, Chungju (Korea, Republic of); Kim, Sung Hun [Daechang Solution Co. Ltd, Busan (Korea, Republic of); Kim, Young Kyun; Kim, Ki Dong [Korean Gas Corporation, R and D Division, Ansan (Korea, Republic of)

    2016-05-15

    Cold stretching(CS) pressure vessels from ASS304 (austenitic stainless steel 304) are used for the transportation and storage of liquefied natural gas(LNG). CS pressure vessels are manufactured by pressurizing the finished vessels to a specific pressure to produce the required stress σk. After CS, there is some degree of plastic deformation. Therefore, CS vessels have a higher strength and lighter weight compared to conventional vessels. In this study, we investigate the tensile and fatigue behavior of ASS304 sampled by CS pressure vessels in accordance with the ASME code at cryogenic temperature. From the fatigue test results, we show S-N curves using a statistical method recommended by JSEM-S002. We carried out the fractography of fractured specimens using scanning electron microscopy (SEM)

  18. Photodynamic ablation of lymphatic vessels and intralymphatic cancer cells prevents metastasis.

    Science.gov (United States)

    Tammela, Tuomas; Saaristo, Anne; Holopainen, Tanja; Ylä-Herttuala, Seppo; Andersson, Leif C; Virolainen, Susanna; Immonen, Ilkka; Alitalo, Kari

    2011-02-09

    The dissemination of tumor cells to sites far from the primary tumor (metastasis) is the principal cause of death in cancer patients. Tumor-associated lymphatic vessels are a key conduit for metastatic tumor cells, which typically first colonize the lymph nodes. Although the primary tumor and affected lymph nodes can be removed during surgery, tumor cells inside lymphatic vessels are left behind. Here, we show that in-transit tumor cells inside lymphatic vessels in mice bearing mouse melanomas or human lung tumors give rise to metastases. Using photodynamic therapy with the benzoporphyrin derivative verteporfin, we selectively destroyed lymphatic vessels in mice and pigs. Destruction of tumor-associated lymphatic vessels also eradicated intralymphatic tumor cells and prevented metastasis of mouse melanoma cells and subsequent relapse. Photodynamic therapy, when combined with anti-lymphangiogenic therapy, prevented further tumor invasion of lymphatic vessels. These findings highlight the potential of targeting in-transit tumor cells in patients.

  19. Modeling the tortuosity of retinal vessels: does caliber play a role?

    Science.gov (United States)

    Trucco, Emanuele; Azegrouz, Hind; Dhillon, Baljean

    2010-09-01

    The tortuosity of retinal blood vessels is a diagnostic parameter assessed by ophthalmologists on the basis of examples and experience; no quantitative model is specified in clinical practice. All quantitative measures proposed to date for automatic image analysis purposes are functions of the curvature of the vessel skeleton. We suggest in this paper that curvature may not be the only quantity involved in modeling tortuosity, and that vessel thickness, or caliber, may also play a role. To support this statement, we devise a novel measure of tortuosity, depending on both curvature and thickness, and test it with 200 vessels selected by our clinical author from the public digital retinal images for vessel extraction database. Results are in good accordance with clinical judgment. Comparative experiments show performance similar to or better than that of four measures reported in the literature. We conclude that there is reasonable evidence supporting the investigation of tortuosity models incorporating more measurements than just skeleton curvature, and specifically vessel caliber.

  20. The association of adult Onchocerca volvulus with lymphatic vessels.

    Science.gov (United States)

    Mackenzie, C D; Huntington, M K; Wanji, S; Lovato, R V; Eversole, R R; Geary, T G

    2010-02-01

    Immunocytochemical examination of onchocercal nodule tissues containing adult Onchocerca volvulus using immuno-markers for blood and lymphatic vessels (vWF, D2-40, podoplanin, Prox-1, and Lyve1) shows a distinct pattern of distribution of these vessels within nodules. Blood vessels were commonly seen associated with organized lymphoid cellular aggregates in the both the outer and inner areas of the nodules. In contrast, the majority of the lymphatic vessel positivity was seen in the central zone in close apposition to the adult parasites, and the remainder usually associated with microfilariae in the outer areas of the nodule. These findings suggest an intimate relationship between adult O. volvulus and lymphatic vessels, including the likely proliferation of lymphatic endothelial cells (lymphangectasia) akin to that seen with other filariae. These findings indicate that adult O. volvulus may migrate via the lymphatic system, and that clinical manifestations of this disease that involve tissue edema may be the result of the location of these worms in the lymphatic system.

  1. Applications of Green Walls in Urban Design

    Science.gov (United States)

    Virtudes, Ana; Manso, Maria

    2016-10-01

    Green walls are a choice towards achieving sustainable urban rehabilitation, due to the lack of free space in the consolidated urban fabric. Nowadays, green walls are considered to be an innovation in the fields of ecology, horticulture or buildings. Nevertheless, in the domain of urban design, they are still surprising and unexpected ideas. Thus, this research aims to reflect on green walls as a feature in urban design and rehabilitation, identifying the advantages of their utilization as an enhancement of the quality of city's image, especially in dense urban areas. It aims to demonstrate some practical applications of green walls in urban design proposals, showing model solutions and their real application in several architectural examples.

  2. New contributions to the wall polysaccharide structure of vegetative mycelium and fruit body cell walls of Agaricus bisporus.

    Science.gov (United States)

    Calonje, M; García Mendoza, C; Novaes-Ledieu, M

    1996-12-01

    Significant differences in chemical composition and structure of wall polysaccharides were found in Agaricus bisporus vegetative mycelium in comparison with the fruit body mycelium. Chemical fractionation of the walls demonstrated distinct percentages of the successively solubilized polysaccharides in both walls, and different proportions of their respective sugar monomers. Permethylation of isolated fractions also showed striking differences relative to the sugar linkages between the two types of walls studied. Furthermore, infrared spectrophotometry exhibited a distinct polysaccharidic configuration in several fractions. All the described differences were correlated with the transition of vegetative mycelial walls to the fruiting stage of differentiation.

  3. Role of PFKFB3-driven glycolysis in vessel sprouting.

    Science.gov (United States)

    De Bock, Katrien; Georgiadou, Maria; Schoors, Sandra; Kuchnio, Anna; Wong, Brian W; Cantelmo, Anna Rita; Quaegebeur, Annelies; Ghesquière, Bart; Cauwenberghs, Sandra; Eelen, Guy; Phng, Li-Kun; Betz, Inge; Tembuyser, Bieke; Brepoels, Katleen; Welti, Jonathan; Geudens, Ilse; Segura, Inmaculada; Cruys, Bert; Bifari, Franscesco; Decimo, Ilaria; Blanco, Raquel; Wyns, Sabine; Vangindertael, Jeroen; Rocha, Susana; Collins, Russel T; Munck, Sebastian; Daelemans, Dirk; Imamura, Hiromi; Devlieger, Roland; Rider, Mark; Van Veldhoven, Paul P; Schuit, Frans; Bartrons, Ramon; Hofkens, Johan; Fraisl, Peter; Telang, Sucheta; Deberardinis, Ralph J; Schoonjans, Luc; Vinckier, Stefan; Chesney, Jason; Gerhardt, Holger; Dewerchin, Mieke; Carmeliet, Peter

    2013-08-01

    Vessel sprouting by migrating tip and proliferating stalk endothelial cells (ECs) is controlled by genetic signals (such as Notch), but it is unknown whether metabolism also regulates this process. Here, we show that ECs relied on glycolysis rather than on oxidative phosphorylation for ATP production and that loss of the glycolytic activator PFKFB3 in ECs impaired vessel formation. Mechanistically, PFKFB3 not only regulated EC proliferation but also controlled the formation of filopodia/lamellipodia and directional migration, in part by compartmentalizing with F-actin in motile protrusions. Mosaic in vitro and in vivo sprouting assays further revealed that PFKFB3 overexpression overruled the pro-stalk activity of Notch, whereas PFKFB3 deficiency impaired tip cell formation upon Notch blockade, implying that glycolysis regulates vessel branching. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Gamma radiography of refractory-lined vessels and components

    Energy Technology Data Exchange (ETDEWEB)

    Lapinski, N. P.

    1978-08-01

    Materials used in coal-conversion systems are exposed to high pressure, high temperature, corrosive and erosive gases, and liquids containing particulate matter. These severe environments necessitate an assessment of the integrity of components to prevent premature failures. Gamma radiography was evaluated as a viable technique for testing such components in the laboratory or after operation in situ. Penetrameters (image-quality indicators) were developed for refractory-lined vessels and transfer lines, and exposure times for various combinations of refractory-steel thicknesses were determined. Radiography with /sup 60/Co was performed on gasifier vessels, combustor vessels, and critical transfer lines in existing pilot plants using the experience gained through laboratory experiments. The results show that gamma radiography is a practical and effective method to detect critical conditions in coal-conversion system components. 18 figures, 3 tables.

  5. Damaging Effects of Multi-walled Carbon Nanotubes on Pregnant Mice with Different Pregnancy Times

    Science.gov (United States)

    Qi, Wei; Bi, Juanjuan; Zhang, Xiaoyong; Wang, Jing; Wang, Jianjun; Liu, Peng; Li, Zhan; Wu, Wangsuo

    2014-03-01

    The mechanism by which nanoparticles cross the placental barrier was studied by using isotopic tracers. The abortion rates and other related data were counted and analysed in pregnant mice with different pregnancy times. Results showed that oxidised multi-walled carbon nanotubes (oMWCNTs) crossed the placental barrier and entered the foetus body. The abortion rates in the pregnant mice depended on pregnancy times. The abortion rates in the first-time, second-time and fourth-time pregnant mice were 70%, 40% and 50%, respectively. The maternal body weight gain was inhibited until gestational ages of 13, 10 and 11 d. oMWCNTs decreased the serum progesterone level and increased the serum oestradiol level in a dose- and time-dependent manner. However, this effect decreased with gestational age. The histology and vascular endothelial growth factor/reactive oxygen species content in the placenta showed that oMWCNTs narrowed the blood vessel and decreased the number of blood vessels in the placenta.

  6. Tracking blood vessels in human forearms using visual servoing

    DEFF Research Database (Denmark)

    Savarimuthu, Thiusius Rajeeth; Ellekilde, Lars-Peter; Hansen, Morten

    compensation. By using images taken with near-infrared light to locate the blood vessels in a human forearm and using the same images to detects movements of the arm, this paper shows that it is possible make a robot arm, potentially equipped with a needle for drawing the blood, compensate for the movements...

  7. Vessel Cauterization as a Therapeutic Adjunct in Persistent ...

    African Journals Online (AJOL)

    This is a case report of a symptomatic non‑clearing, vascularized, disciform, corneal stromal edema with a feeder vessel that has remained refractory to medical therapy of antiviral, steroid, and antibiotics, for a period of three weeks, but showed a rapid improvement in visual acuity of 0.1 Log mar within five days of feeder ...

  8. Hemodynamics in stenotic vessels of small diameter under steady state conditions: Effect of viscoelasticity and migration of red blood cells.

    Science.gov (United States)

    Dimakopoulos, Yannis; Kelesidis, George; Tsouka, Sophia; Georgiou, Georgios C; Tsamopoulos, John

    2015-01-01

    In microcirculation, the non-Newtonian behavior of blood and the complexity of the microvessel network are responsible for the high flow resistance and the large reduction of the blood pressure. Red blood cell aggregation along with inward radial migration are two significant mechanisms determining the former. Yet, their impact on hemodynamics in non-straight vessels is not well understood. In this study, the steady state blood flow in stenotic rigid vessels is examined, employing a sophisticated non-homogeneous constitutive law. The effect of red blood cells migration on the hydrodynamics is quantified and the constitutive model's accuracy is evaluated. A numerical algorithm based on the two-dimensional mixed finite element method and the EVSS/SUPG technique for a stable discretization of the mass and momentum conservation equations in addition to the constitutive model is employed. The numerical simulations show that a cell-depleted layer develops along the vessel wall with an almost constant thickness for slow flow conditions. This causes the reduction of the drag force and the increase of the pressure gradient as the constriction ratio decreases. Viscoelastic effects in blood flow were found to be responsible for steeper decreases of tube and discharge hematocrits as decreasing function of constriction ratio.

  9. Nonlinear dynamic behavior of microscopic bubbles near a rigid wall

    Science.gov (United States)

    Suslov, Sergey A.; Ooi, Andrew; Manasseh, Richard

    2012-06-01

    The nonlinear dynamic behavior of microscopic bubbles near a rigid wall is investigated. Oscillations are driven by the ultrasonic pressure field that arises in various biomedical applications such as ultrasound imaging or targeted drug delivery. It is known that, when bubbles approach a blood-vessel wall, their linear dynamic response is modified. This modification may be very useful for real-time detection of bubbles that have found targets; in future therapeutic technologies, it may be useful for controlled release of medical agents encapsulating microbubbles. In this paper, the nonlinear response of microbubbles near a wall is studied. The Keller-Miksis-Parlitz equation is adopted, but modified to account for the presence of a rigid wall. This base model describes the time evolution of the bubble surface, which is assumed to remain spherical, and accounts for the effect of acoustic radiation losses owing to liquid compressibility in the momentum conservation. Two situations are considered: the base case of an isolated bubble in an unbounded medium, and a bubble near a rigid wall. In the latter case, the wall influence is modeled by including a symmetrically oscillating image bubble. The bubble dynamics is traced using a numerical solution of the model equation. Subsequently, Floquet theory is used to accurately detect the bifurcation point where bubble oscillations stop following the driving ultrasound frequency and undergo period-changing bifurcations. Of particular interest is the detection of the subcritical period-tripling and -quadrupling transition. The parametric bifurcation maps are obtained as functions of nondimensional parameters representing the bubble radius, the frequency and pressure amplitude of the driving ultrasound field, and the distance from the wall. It is shown that the presence of the wall generally stabilises the bubble dynamics, so that much larger values of the pressure amplitude are needed to generate nonlinear responses. Thus, a

  10. Precise spatial control of cavitation erosion in a vessel phantom by using an ultrasonic standing wave.

    Science.gov (United States)

    Shi, Aiwei; Huang, Peixuan; Guo, Shifang; Zhao, Lu; Jia, Yingjie; Zong, Yujin; Wan, Mingxi

    2016-07-01

    In atherosclerotic inducement in animal models, the conventionally used balloon injury is invasive, produces excessive vessel injuries at unpredictable locations and is inconvenient in arterioles. Fortunately, cavitation erosion, which plays an important role in therapeutic ultrasound in blood vessels, has the potential to induce atherosclerosis noninvasively at predictable sites. In this study, precise spatial control of cavitation erosion for superficial lesions in a vessel phantom was realised by using an ultrasonic standing wave (USW) with the participation of cavitation nuclei and medium-intensity ultrasound pulses. The superficial vessel erosions were restricted between adjacent pressure nodes, which were 0.87 mm apart in the USW field of 1 MHz. The erosion positions could be shifted along the vessel by nodal modulation under a submillimetre-scale accuracy without moving the ultrasound transducers. Moreover, the cavitation erosion of the proximal or distal wall could be determined by the types of cavitation nuclei and their corresponding cavitation pulses, i.e., phase-change microbubbles with cavitation pulses of 5 MHz and SonoVue microbubbles with cavitation pulses of 1 MHz. Effects of acoustic parameters of the cavitation pulses on the cavitation erosions were investigated. The flow conditions in the experiments were considered and discussed. Compared to only using travelling waves, the proposed method in this paper improves the controllability of the cavitation erosion and reduces the erosion depth, providing a more suitable approach for vessel endothelial injury while avoiding haemorrhage. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Neuroradiologic Characteristics of Primary Angiitis of the Central Nervous System According to the Affected Vessel Size.

    Science.gov (United States)

    Thaler, Christian; Kaufmann-Bühler, Ann-Katrin; Gansukh, Tserenchunt; Gansukh, Amarjargal; Schuster, Simon; Bachmann, Henrike; Thomalla, Götz; Magnus, Tim; Matschke, Jakob; Fiehler, Jens; Siemonsen, Susanne

    2017-09-05

    Magnetic resonance imaging (MRI) has an important impact in diagnosing primary angiitis of the central nervous system (PACNS). However, neuroradiologic findings may vary immensely, making an easy and definite diagnosis challenging. In this retrospective, single center study, we analyzed neuroradiologic findings of patients with PACNS diagnosed at our hospital between 2009 and 2014. Furthermore, we classified patients according to the affected vessel size and compared imaging characteristics between the subgroups. Thirty-three patients were included (mean age 43 [±15.3] years, 17 females) in this study. Patients with positive angiographic findings were classified as either medium or large vessel PACNS and presented more ischemic lesions (p < 0.001) and vessel wall enhancement (p = 0.017) compared to patients with small vessel PACNS. No significant differences were detected for the distribution of contrast-enhancing lesions (parenchymal or leptomeningeal), hemorrhages, or lesions with mass effect. Twenty-five patients underwent brain biopsy. Patients with medium or large vessel PACNS were less likely to have positive biopsy results. It is essential to differentiate between small and medium/large vessel PACNS since results in MRI, digital subtraction angiography and brain biopsy may differ immensely. Since image quality of MR scanners improves gradually and brain biopsy may often be nonspecific or negative, our results emphasize the importance of MRI/MRA in the diagnosis process of PACNS.

  12. In vivo visualization of the final stages of xylem vessel refilling in grapevine (Vitis vinifera) stems.

    Science.gov (United States)

    Brodersen, Craig R; Knipfer, Thorsten; McElrone, Andrew J

    2018-01-01

    Embolism removal is critical for restoring hydraulic pathways in some plants, as residual gas bubbles should expand when vessels are reconnected to the transpiration stream. Much of our understanding of embolism removal remains theoretical as a consequence of the lack of in vivo images of the process at high magnification. Here, we used in vivo X-ray micro-computed tomography (microCT) to visualize the final stages of xylem refilling in grapevine (Vitis vinifera) paired with scanning electron microscopy. Before refilling, vessel walls were covered with a surface film, but vessel perforation plate openings and intervessel pits were filled with air. Bubbles were removed from intervessel pits first, followed by bubbles within perforation plates, which hold the last volumes of air which eventually dissolve. Perforation plates were dimorphic, with more steeply angled scalariform plates in narrow diameter vessels, compared with the simple perforation plates in older secondary xylem, which may favor rapid refilling and compartmentalization of embolisms that occur in small vessels, while promoting high hydraulic conductivity in large vessels. Our study provides direct visual evidence of the spatial and temporal dynamics of the final stages of embolism removal. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  13. A scaling and experimental approach for investigating in-vessel cooling

    Energy Technology Data Exchange (ETDEWEB)

    Henry, R.E. [Fauske & Associates, Inc., Burr Ridge, IL (United States)

    1997-02-01

    The TMI-2 accident experienced the relocation of a large quantity of core material to the lower plenum. The TMI-2 vessel investigation project concluded that approximately 20 metric tonnes of once molten fuel material drained into the RPV lower head. As a result, the lower head wall experienced a thermal transient that has been characterized as reaching temperatures as high as 1100{degrees}C, then a cooling transient with a rate of 10 to 100{degrees}C/min. Two mechanisms have been proposed as possible explanations for this cooling behavior. One is the ingression of water through core material as a result of interconnected cracks in the frozen debris and/or water ingression around the crust which is formed on internal structures (core supports and in-core instrumentation) in the lower head. The second focuses on the lack of adhesion of oxidic core debris to the RPV wall when the debris contacts the wall. Furthermore, the potential for strain of the RPV lower head when the wall is overheated could provide for a significant cooling path for water to ingress between the RPV and the frozen core material next to the wall. To examine these proposed mechanisms, a set of scaled experiments have been developed to examine the potential for cooling. These are performed in a scaled system in which the high temperature molten material is iron termite and the RPV wall is carbon steel. A termite mass of 40 kg is used and the simulated reactor vessels have water in the lower head at pressures up to 2.2 MPa. Furthermore, two different thicknesses of the vessel wall are examined with the thicker vessel having virtually no potential for material creep during the experiment and the thinner wall having the potential for substantial creep. Moreover, the experiment includes the option of having molten iron as the first material to drain into the RPV lower head or molten aluminum oxide being the only material that drains into the test configuration.

  14. WITHDRAWN: The extended abdominal wall flap for transplantation.

    Science.gov (United States)

    Hollenbeck, S T; Senghaas, A; Turley, R; Ravindra, K V; Zenn, M R; Levin, L S; Erdmann, D

    2011-11-01

    Patients with extensive loss of abdominal wall tissue have few options for restoring the abdominal cavity. Composite tissue allotransplantation has been used for limited abdominal wall reconstruction in the setting of visceral transplantation, yet replacement of the entire abdominal wall has not been described. The purpose of this study was to determine the maximal abdominal skin surface available through an external iliac/femoral cuff-based pedicle. Five human cadaver abdominal walls were injected with methylene blue to analyze skin perfusion based on either the deep inferior epigastric artery (DIEA; n = 5) or a cuff of external iliac/femoral artery (n = 5) containing the deep circumflex iliac, deep inferior epigastric, superficial inferior epigastric, and the superficial circumflex iliac arteries. Abdominal wall flaps were taken full thickness from the costal margin to the mid-axial line and down to the pubic tubercle and proximal thigh. In all specimens, the deep inferior epigastric, deep circumflex iliac, superficial inferior epigastric, and the superficial circumflex iliac arteries were found to originate within a 4-cm cuff of the external iliac/femoral artery. Abdominal wall flaps injected through a unilateral external iliac/femoral segment had a significantly greater degree of total flap perfusion than those injected through the DIEA alone (76.5 +/- 4% versus 57.2 +/- 5%; Student t test, P DIEA vessel alone. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Free DNA precipitates calcium phosphate apatite crystals in the arterial wall in vivo.

    Science.gov (United States)

    Coscas, Raphaël; Bensussan, Marie; Jacob, Marie-Paule; Louedec, Liliane; Massy, Ziad; Sadoine, Jeremy; Daudon, Michel; Chaussain, Catherine; Bazin, Dominique; Michel, Jean-Baptiste

    2017-04-01

    The arterial wall calcium score and circulating free DNA levels are now used in clinical practice as biomarkers of cardiovascular risk. Calcium phosphate apatite retention in the arterial wall necessitates precipitation on an anionic platform. Here, we explore the role of tissue-free DNA as such a platform. The first step consisted of histological observation of samples from human and rat calcified arteries. Various stains were used to evaluate colocalization of free DNA with calcified tissue (alizarin red, fluorescent Hoechst, DNA immunostaining and TUNEL assay). Sections were treated by EDTA to reveal calcification background. Secondly, a rat model of vascular calcifications induced by intra-aortic infusions of free DNA and elastase + free DNA was developed. Rat aortas underwent a micro-CT for calcium score calculation at 3 weeks. Rat and human calcifications were qualitatively characterized using μFourier Transform Infrared Spectroscopy (μFTIR) and Field Emission-Scanning Electron Microscopy (FE-SEM). Our histological study shows colocalization of calcified arterial plaques with free DNA. In the intra-aortic infusion model, free DNA was able to penetrate into the arterial wall and induce calcifications whereas no microscopic calcification was seen in control aortas. The calcification score in the elastase + free DNA group was significantly higher than in the control groups. Qualitative evaluation with μFTIR and FE-SEM demonstrated typical calcium phosphate retention in human and rat arterial specimens. This translational study demonstrates that free DNA could be involved in arterial calcification formation by precipitating calcium phosphate apatite crystals in the vessel wall. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. New vessel formation and aberrant VEGF/VEGFR signaling in acute leukemia : Does it matter?

    NARCIS (Netherlands)

    De Bont, ESJM; Neefjes, VME; Rosati, S; Vellenga, E; Kamps, WA

    2002-01-01

    Although many patients with acute leukemia achieve a hematological complete remission with aggressive intensive therapy protocols, a large proportion shows reoccurrence of disease. Novel strategies are warranted. In acute leukemia new vessel formation is observed. New vessel formation is the result

  17. Vessel co-option mediates resistance to anti-angiogenic therapy in liver metastases

    NARCIS (Netherlands)

    Frentzas, Sophia; Simoneau, Eve; Bridgeman, Victoria L.; Vermeulen, Peter B.; Foo, Shane; Kostaras, Eleftherios; Nathan, Mark R.; Wotherspoon, Andrew; Gao, Zu Hua; Shi, Yu; Van Den Eynden, Gert; Daley, Frances; Peckitt, Clare; Tan, Xianming; Salman, Ayat; Lazaris, Anthoula; Gazinska, Patrycja; Berg, Tracy J.; Eltahir, Zak; Ritsma, L.; Van Rheenen, Jacco; Khashper, Alla; Brown, Gina; Nyström, Hanna; Sund, Malin; Van Laere, Steven; Loyer, Evelyne; Dirix, Luc; Cunningham, David; Metrakos, Peter; Reynolds, Andrew R.

    2016-01-01

    The efficacy of angiogenesis inhibitors in cancer is limited by resistance mechanisms that are poorly understood. Notably, instead of through the induction of angiogenesis, tumor vascularization can occur through the nonangiogenic mechanism of vessel co-option. Here we show that vessel co-option is

  18. Multiscale FEM modeling of vascular tone: from membrane currents to vessel mechanics.

    Science.gov (United States)

    Kapela, Adam; Tsoukias, Nikolaos Michael

    2011-12-01

    Regulation of vascular tone is a complex process that remains poorly understood. Here, we present our recent efforts for the development of physiologically realistic models of arterial segments for the analysis of vasoreactivity in health and disease. Multiscale modeling integrates intracellular and cell membrane components into whole-cell models of calcium and membrane potential dynamics. Single-cell models of vascular cells are combined into a multicellular model of the vascular wall, and vessel wall biomechanics are integrated with calcium dynamics in the smooth muscle layer. At each scale, continuum models using finite element method can account for spatial heterogeneity in calcium signaling and for nonuniform deformations of a vessel segment. The outlined approach can be used to investigate cellular mechanisms underlying altered vasoreactivity in hypertension.

  19. Moisture Research - Optimizing Wall Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Arena, Lois [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Mantha, Pallavi [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States)

    2013-05-01

    In this project, the Consortium for Advanced Residential Buildings (CARB) team evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls. Wall assemblies evaluated included code minimum walls using spray foam insulation and fiberglass batts, high R-value walls at least 12 in. thick (R-40 and R-60 assemblies), and brick walls with interior insulation.

  20. Universal hydraulics of the flowering plants: vessel diameter scales with stem length across angiosperm lineages, habits and climates.

    Science.gov (United States)

    Olson, Mark E; Anfodillo, Tommaso; Rosell, Julieta A; Petit, Giai; Crivellaro, Alan; Isnard, Sandrine; León-Gómez, Calixto; Alvarado-Cárdenas, Leonardo O; Castorena, Matiss

    2014-08-01

    Angiosperm hydraulic performance is crucially affected by the diameters of vessels, the water conducting conduits in the wood. Hydraulic optimality models suggest that vessels should widen predictably from stem tip to base, buffering hydrodynamic resistance accruing as stems, and therefore conductive path, increase in length. Data from 257 species (609 samples) show that vessels widen as predicted with distance from the stem apex across angiosperm orders, habits and habitats. Standardising for stem length, vessels are only slightly wider in warm/moist climates and in lianas, showing that, rather than climate or habit, plant size is by far the main driver of global variation in mean vessel diameter. Terminal twig vessels become wider as plant height increases, while vessel density decreases slightly less than expected tip to base. These patterns lead to testable predictions regarding evolutionary strategies allowing plants to minimise carbon costs per unit leaf area even as height increases. © 2014 John Wiley & Sons Ltd/CNRS.

  1. Concentration polarization effects on the macromolecular transport in the presence of non-uniform magnetic field: A numerical study using a lumen-wall model

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadpourfard, M., E-mail: Mohammadpour@azaruniv.edu [Department of Mechanical Engineering, Azarbaijan Shahid Madani University, Tabriz 53751-71379 (Iran, Islamic Republic of); Aminfar, H., E-mail: hh_aminfar@tabrizu.ac.ir [Faculty of Mechanical Engineering, University of Tabriz, Tabriz (Iran, Islamic Republic of); Khajeh, K., E-mail: khajeh.k.2005@gmail.com [Faculty of Mechanical Engineering, University of Tabriz, Tabriz (Iran, Islamic Republic of)

    2014-04-01

    In this paper, the concentration polarization phenomena in a two dimensional tube under steady state conditions containing ferrofluid (blood and 4 vol% Fe{sub 3}O{sub 4}) is reported in the presence of non-uniform magnetic field. Lumen-wall model has been used for solving the mass transport equation. Hemodynamics parameters such as flow rate, viscosity, wall shear stress (WSS) and the macromolecules surface concentration which accumulate on the blood vessel wall, influenced the formation and progression of atherosclerosis disease. Effective parameters on the low density lipoprotein (LDL) surface concentration (LSC) such as: the wall filtration velocity, inlet Reynolds number and WSS under applied non-uniform magnetic field have been examined. Numerical solution of governing equations of the flow field have been obtained by using the single-phase model and the control volume technique. Magnetic field is generated by an electric current going through a thin and straight wire oriented perpendicular to the tube. Results show WSS in the vicinity of magnetic field source increased and LSC decreased along the wall. - Highlights: • In this paper the concentration polarization phenomena of blood flow is reported in the presence of non-uniform magnetic field. • In presence of non-uniform magnetic field LSC will decrease along the wall due to the increasing the velocity gradients near the magnetic source. • When non-uniform magnetic field intensity increases, LSC along the wall becomes lower. • Non-uniform magnetic field can affects the flow more in low Reynolds numbers.

  2. A simple design for microwave assisted digestion vessel with low reagent consumption suitable for food and environmental samples

    Science.gov (United States)

    Gholami, Mehrdad; Behkami, Shima; Zain, Sharifuddin Md.; Bakirdere, Sezgin

    2016-11-01

    The objective of this work is to prepare a cost-effective, low reagent consumption and high performance polytetrafluoroethylene (PTFE) vessel that is capable to work in domestic microwave for digesting food and environmental samples. The designed vessel has a relatively thicker wall compared to that of commercial vessels. In this design, eight vessels are placed in an acrylonitrile butadiene styrene (ABS) holder to keep them safe and stable. This vessel needs only 2.0 mL of HNO3 and 1.0 mL H2O2 to digest 100 mg of biological sample. The performance of this design is then evaluated with an ICP-MS instrument in the analysis of the several NIST standard reference material of milk 1849a, rice flour 1568b, spinach leave 1570a and Peach Leaves 1547 in a domestic microwave oven with inverter technology. Outstanding agreement to (SRM) values are observed by using the suggested power to time microwave program, which simulates the reflux action occurring in this closed vessel. Taking into account the high cost of commercial microwave vessels and the volume of chemicals needed for various experiments (8-10 mL), this simple vessel is cost effective and suitable for digesting food and environmental samples.

  3. Robust ferromagnetism carried by antiferromagnetic domain walls

    Science.gov (United States)

    Hirose, Hishiro T.; Yamaura, Jun-Ichi; Hiroi, Zenji

    2017-02-01

    Ferroic materials, such as ferromagnetic or ferroelectric materials, have been utilized as recording media for memory devices. A recent trend for downsizing, however, requires an alternative, because ferroic orders tend to become unstable for miniaturization. The domain wall nanoelectronics is a new developing direction for next-generation devices, in which atomic domain walls, rather than conventional, large domains themselves, are the active elements. Here we show that atomically thin magnetic domain walls generated in the antiferromagnetic insulator Cd2Os2O7 carry unusual ferromagnetic moments perpendicular to the wall as well as electron conductivity: the ferromagnetic moments are easily polarized even by a tiny field of 1 mT at high temperature, while, once cooled down, they are surprisingly robust even in an inverse magnetic field of 7 T. Thus, the magnetic domain walls could serve as a new-type of microscopic, switchable and electrically readable magnetic medium which is potentially important for future applications in the domain wall nanoelectronics.

  4. Structure and mechanics of starfish body wall.

    Science.gov (United States)

    O'Neill, P

    1989-11-01

    The structure of the dorsal body wall of the starfish Echinaster spinulosus was studied using polarized light microscopy of frozen tissues, scanning electron microscopy and histology. The collagen fibres of the body wall form a three-dimensional orthogonal web. Voids in the web contain ossicles and papulae. The orthogonal web delivers dimensional stability but allows shear necessary for ray torsion. The ossicles and fibres interact to load the fibres in tension and the ossicles in compression. Strain rates of the dorsal body wall were measured on live animals during typical movements. Uniaxial tension tests of the body wall yielded Young's moduli of 267 MPa (longitudinal), 249 MPa (transverse) and 353 MPa (bias); curves were essentially linear. The body wall was approximately linearly viscoelastic and showed hysteresis at 0.01 Hz. Stress relaxation over five decades of time (in seconds) yielded relaxation spectra with peaks in relaxation time at 2.96-3.35, depending on test direction. Stress relaxation caused the connective tissue to soften. The surface of fractured stress-relaxed tissue revealed wispy, dissociated fibril tufts, whereas unrelaxed fractures produced blunt-ended fibre bundles. Neural control was necessary for body wall integrity.

  5. Mathematical Models and Numerical Simulations for the Blood Flow in Large Vessels

    OpenAIRE

    Titus PETRILA; Balazs ALBERT

    2012-01-01

    We are proposing a non-Newtonian, Cross type rheological model for the blood flow, under the conditions of an unsteady flow regime connected with the rhythmic pumping of the blood by the heart. We admit the incompressibility and homogeneity of the blood while its flow is laminar and the exterior body forces are neglected. We take also into account the viscoelastic behavior of the vessel walls. The mathematical equations and the appropriate boundary conditions are considered in cylindrical (ax...

  6. Effect of gravitation stress and hypokinesia on blood vessels of the testicle

    Science.gov (United States)

    Palazhchenko, E. F.

    1979-01-01

    Rabbits were exposed to single maximum endurable stresses of cranio-caudal direction, hypokinesia for periods of one to eight weeks, and hypokinesia followed by gravitation stresses. The stresses caused dilatation of vessels, greater sinuosity, and occasional ruptures of the walls and extravasation. The greater part of the capillaries were dilated; the greatest part constricted. In hypokinesia there was an increasing atrophy of the testes. Significant results are reported.

  7. MR lymphography of lymphatic vessels in lower extremity with gynecologic oncology-related lymphedema.

    Science.gov (United States)

    Lu, Qing; Delproposto, Zachary; Hu, Alice; Tran, Christine; Liu, Ningfei; Li, Yulai; Xu, Jianrong; Bui, Duy; Hu, Jiani

    2012-01-01

    To characterize lymphatic vessel morphology in lower extremity lymphedema using MR lymphography at 3T. Forty females with lower extremity lymphedema secondary to gynecologic carcinoma treatment underwent MR lymphography (MRL) at 3T. Lymphatic vessel morphology in normal and affected limbs was compared. The median diameter of the lymphatic vessels in swollen calf and thigh were significantly larger than that in the contralateral calf and thigh, respectively (plymphatic vessels visualized in normal calf was less than that in the lymphedematous calf (pLymphatic vessel number in the affected calf was significantly greater than that in affected thigh and the mean diameter of affected calf was also significantly wider than that of affected thigh (plymphatic vessels in the affected calf was significantly different between stage I and stage III (p0.05). The median number of lymphatic vessels for affected calf showed significant difference between stage I and stage III, and between stage II and stage III (p0.05). There was no significant difference in mean diameter or median number of lymphatic vessels in the affected thigh found between different stages (p>0.05). There are significant differences in the number or diameter of lymphatic vessels between normal and affected limbs and there are significant differences for affected calf between early and late stages of lymphedema; therefore, MR lymphography can be helpful in diagnosis or clinical staging for lower extremity with gynecologic oncology-related lymphedema.

  8. Fourier cross-sectional profile for vessel detection on retinal images.

    Science.gov (United States)

    Zhu, Tao

    2010-04-01

    Retinal blood vessels are important objects in ophthalmologic images. In spite of many attempts for vessel detection, it appears that existing methodologies are based on edge detection or modeling of vessel cross-sectional profiles in intensity. The application of these methodologies is hampered by the presence of a wide range of retinal vessels. In this paper we define a universal representation for upward and downward vessel cross-sectional profiles with varying boundary sharpness. This expression is used to define a new scheme of vessel detection based on symmetry and asymmetry in the Fourier domain. Phase congruency is utilized for measuring symmetry and asymmetry so that our scheme is invariant to vessel brightness variations. We have performed experiments on fluorescein images and color fundus images to show the efficiency of the proposed algorithm technique. We also have performed a width measurement study, using an optimal medial axis skeletonization scheme as a post-processing step, to compare the technique with the generalized Gaussian profile modeling. The new algorithm technique is promising for automated vessel detection where optimizing profile models is difficult and preserving vessel width information is necessary. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  9. Modelling of pressure increase protection system for the vacuum vessel of W7-X device

    Energy Technology Data Exchange (ETDEWEB)

    Kaliatka, Tadas, E-mail: tadas.kaliatka@lei.lt; Uspuras, Eugenijus; Kaliatka, Algirdas

    2016-11-01

    Highlights: • Two in-vessel LOCAs (partial and guillotine break of 40 mm diameter pipe of cooling system) for Wendelstein 7-X fusion device were analyzed. • The analysis of the processes in the cooling system, vacuum vessel and pressure increase protection system were performed using thermal-hydraulic RELAP5 Mod3.3 code. • The suitability of pressure increase protection system was assessed. - Abstract: In fusion devices, plasma is contained in a vacuum vessel. The vacuum vessel cannot withstand a pressure above atmospheric. Any damage of in-vessel components could lead to water ingress and may lead to pressure increase and possible damage of vacuum vessel. In order to avoid such undesirable consequences, the pressure increase protection system is designed. In this article, the processes occurring in the vacuum vessel and pressure increase protection system of W7-X device during LOCA (small and guillotine pipe break) event are analyzed. The model of W7-X cooling system, vacuum vessel and pressure increase protection system was developed using RELAP5 code. Numerical analysis of partial and guillotine break of 40 mm diameter pipe of cooling system was performed. Calculation results showed that burst disc of the pressure increase protection system does not open when the cross section area of partial break in the cooling system is smaller than 1 mm{sup 2}. During the guillotine break of cooling system, the burst disc opens, but pressure increase protection system is capable to prevent overpressure of the vacuum vessel.

  10. High-R Walls for Remodeling: Wall Cavity Moisture Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Wiehagen, J.; Kochkin, V.

    2012-12-01

    The focus of the study is on the performance of wall systems, and in particular, the moisture characteristics inside the wall cavity and in the wood sheathing. Furthermore, while this research will initially address new home construction, the goal is to address potential moisture issues in wall cavities of existing homes when insulation and air sealing improvements are made.

  11. High-R Walls for Remodeling. Wall Cavity Moisture Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Wiehagen, J. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Kochkin, V. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States)

    2012-12-01

    The focus of the study is on the performance of wall systems, and in particular, the moisture characteristics inside the wall cavity and in the wood sheathing. Furthermore, while this research will initially address new home construction, the goal is to address potential moisture issues in wall cavities of existing homes when insulation and air sealing improvements are made.

  12. Identification of Novel Cell Wall Components

    Energy Technology Data Exchange (ETDEWEB)

    Michelle Momany

    2009-10-26

    Our DOE Biosciences-funded work focused on the fungal cell wall and morphogenesis. We are especially interested in how new cell wall material is targeted to appropriate areas for polar (asymmetric) growth. Polar growth is the only way that filamentous fungi explore the environment to find suitable substrates to degrade. Work funded by this grant has resulted in a total of twenty peer-reviewed publications. In work funded by this grant, we identified nine Aspergillus nidulans temperature-sensitive (ts) mutants that fail to send out a germ tube and show a swollen cell phenotype at restrictive temperature, the swo mutants. In other organisms, a swollen cell phenotype is often associated with misdirected growth or weakened cell walls. Our work shows that several of the A. nidulans swo mutants have defects in the establishment and maintenance of polarity. Cloning of several swo genes by complementation also showed that secondary modification of proteins seems is important in polarity. We also investigated cell wall biosynthesis and branching based on leads in literature from other organisms and found that branching and nuclear division are tied and that the cell wall reorganizes during development. In our most recent work we have focused on gene expression during the shift from isotropic to polar growth. Surprisingly we found that genes previously thought to be involved only in spore formation are important in early vegetative growth as well.

  13. Follicular thyroid carcinoma invades venous rather than lymphatic vessels

    Directory of Open Access Journals (Sweden)

    Liu Yulin

    2010-01-01

    Full Text Available Abstract Follicular thyroid carcinoma (FTC tends to metastasize to remote organs rather than local lymph nodes. Separation of FTC from follicular thyroid adenoma (FTA relies on detection of vascular and/or capsular invasion. We investigated which vascular markers, CD31, CD34 and D2-40 (lymphatic vessel marker, can best evaluate vascular invasion and why FTC tends to metastasize via blood stream to remote organs. Thirty two FTCs and 34 FTAs were retrieved for evaluation. The average age of patients with FTA was 8 years younger than FTC (p = 0.02. The female to male ratio for follicular neoplasm was 25:8. The average size of FTC was larger than FTA (p = 0.003. Fourteen of 32 (44% FTCs showed venous invasion and none showed lymphatic invasion, with positive CD31 and CD34 staining and negative D2-40 staining of the involved vessels. The average number of involved vessels was 0.88 ± 1.29 with a range from 0 to 5, and the average diameter of involved vessels was 0.068 ± 0.027 mm. None of the 34 FTAs showed vascular invasion. CD31 staining demonstrated more specific staining of vascular endothelial cells than CD34, with less background staining. We recommended using CD31 rather than CD34 and/or D2-40 in confirming/excluding vascular invasion in difficult cases. All identified FTCs with vascular invasions showed involvement of venous channels, rather than lymphatic spaces, suggesting that FTCs prefer to metastasize via veins to distant organs, instead of lymphatic vessels to local lymph nodes, which correlates with previous clinical observations.

  14. The wall traction induced by flowing red blood cells in model microvessels and its potential mechanotransduction

    Science.gov (United States)

    Freund, Jonathan; Vermot, Julien

    2013-11-01

    There is evidence in early embryonic development, even well before advective oxygen transport is important, that the presence of red bloods cells per se trigger essential steps of normal vascular development. For example, showed that sequestration of blood cells early in the development of a mouse, such that the hematocrit is reduced, suppresses normal vascular network development. Vascular development also provides a model for remodeling and angiogenesis. We consider the transient stresses associated with blood cells flowing in model microvessels of comparable diameter to those at early stages of development (6 μm to 12 μm). A detailed simulation tool is used to show that passing blood cells present a significant fluctuating traction signature on the vessel wall, well above the mean stresses. This is particularly pronounced for slow flows (<= 50 μm/s) or small diameters (<= 7 μm), for which root-mean-square wall traction fluctuations can exceed their mean. These events potentially present mechanotranduction triggers that direct development or remodeling. Attenuation of such fluctuating tractions by a viscoelastic endothelial glycocalyx layer is also considered. NSF supported.

  15. DIELECTRIC WALL ACCELERATOR TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Sampayan, S; Caporaso, G; Chen, Y; Harris, J; Hawkins, S; Holmes, C; Nelson, S; Poole, B; Rhodes, M; Sanders, D; Sullivan, J; Wang, L; Watson, J

    2007-10-18

    The dielectric wall accelerator (DWA) is a compact pulsed power device where the pulse forming lines, switching, and vacuum wall are integrated into a single compact geometry. For this effort, we initiated a extensive compact pulsed power development program and have pursued the study of switching (gas, oil, laser induced surface flashover and photoconductive), dielectrics (ceramics and nanoparticle composites), pulse forming line topologies (asymmetric and symmetric Blumleins and zero integral pulse forming lines), and multilayered vacuum insulator (HGI) technology. Finally, we fabricated an accelerator cell for test on ETAII (a 5.5 MeV, 2 kA, 70 ns pulsewidth electron beam accelerator). We review our past results and report on the progress of accelerator cell testing.

  16. Anterior chest wall examination reviewed

    Directory of Open Access Journals (Sweden)

    F. Trotta

    2011-09-01

    Full Text Available Anterior chest wall involvement is not infrequently observed within inflammatory arthropaties, particularly if one considers seronegative spondiloarthritides and SAPHO syndrome. Physical examination is unreliable and conventional X-rays analysis is an unsatisfactory tool during diagnostic work-up of this region. Scintigraphic techniques yield informations both on the activity and on the anatomical extent of the disease while computerized tomography visualize the elementary lesions, such as erosions, which characterize the process. Moreover, when available, magnetic resonance imaging couple the ability to finely visualize such lesions with the possibility to show early alterations and to characterize the “activity” of the disease, presenting itself as a powerful tool both for diagnosis and follow-up. This review briefly shows the applications of imaging techniques for the evaluation of the anterior chest wall focusing on what has been done in the SAPHO syndrome which can be considered prototypical for this regional involvement since it is the osteo-articular target mainly affected by the disease.

  17. Partial domain wall partition functions

    National Research Council Canada - National Science Library

    Foda, O; Wheeler, M

    2012-01-01

    We consider six-vertex model configurations on an (n × N) lattice, n ≤ N, that satisfy a variation on domain wall boundary conditions that we define and call partial domain wall boundary conditions...

  18. Effect of a soluble surfactant on a finite sized bubble motion in a blood vessel

    Science.gov (United States)

    Swaminathan, T. N.; Mukundakrishnan, K.; Ayyaswamy, P. S.; Eckmann, D. M.

    2009-01-01

    We present detailed results for the motion of a finite sized gas bubble in a blood vessel. The bubble (dispersed phase) size is taken to be such as to nearly occlude the vessel. The bulk medium is treated as a shear thinning Casson fluid and contains a soluble surfactant that adsorbs and desorbs from the interface. Three different vessel sizes, corresponding to a small artery, a large arteriole, and a small arteriole, in normal humans, are considered. The hematocrit (volume fraction of RBCs) has been taken to be 0.45. For arteriolar flow, where relevant, the Fahraeus-Lindqvist effect is taken into account. Bubble motion cause temporal and spatial gradients of shear stress at the cell surface lining the vessel wall as the bubble approaches the cell, moves over it and passes it by. Rapid reversals occur in the sign of the shear stress imparted to the cell surface during this motion. Shear stress gradients together with sign reversals are associated with a recirculation vortex at the rear of the moving bubble. The presence of the surfactant reduces the level of the shear stress gradients imparted to the cell surface as compared to an equivalent surfactant-free system. Our numerical results for bubble shapes and wall shear stresses may help explain phenomena observed in experimental studies related to gas embolism, a significant problem in cardiac surgery and decompression sickness. PMID:20305744

  19. Scalable Resolution Display Walls

    KAUST Repository

    Leigh, Jason

    2013-01-01

    This article will describe the progress since 2000 on research and development in 2-D and 3-D scalable resolution display walls that are built from tiling individual lower resolution flat panel displays. The article will describe approaches and trends in display hardware construction, middleware architecture, and user-interaction design. The article will also highlight examples of use cases and the benefits the technology has brought to their respective disciplines. © 1963-2012 IEEE.

  20. Vessel classification method based on vessel behavior in the port of Rotterdam

    NARCIS (Netherlands)

    Zhou, Y.; Daamen, W.; Vellinga, T.; Hoogendoorn, S.P.

    2015-01-01

    AIS (Automatic Identification System) data have proven to be a valuable source to investigate vessel behavior. The analysis of AIS data provides a possibility to recognize vessel behavior patterns in a waterway area. Furthermore, AIS data can be used to classify vessel behavior into several

  1. A computational algorithm addressing how vessel length might depend on vessel diameter

    Science.gov (United States)

    Jing Cai; Shuoxin Zhang; Melvin T. Tyree

    2010-01-01

    The objective of this method paper was to examine a computational algorithm that may reveal how vessel length might depend on vessel diameter within any given stem or species. The computational method requires the assumption that vessels remain approximately constant in diameter over their entire length. When this method is applied to three species or hybrids in the...

  2. 76 FR 59660 - Proposed Information Collection; Comment Request; Permitting, Vessel Identification, and Vessel...

    Science.gov (United States)

    2011-09-27

    ...; Permitting, Vessel Identification, and Vessel Monitoring System Requirements for the Commercial Bottomfish... compliance with federal identification requirements and carry and maintain a satellite- based vessel monitoring system (VMS). This collection of information is needed for permit issuance, to identify actual or...

  3. Light shining through walls

    Energy Technology Data Exchange (ETDEWEB)

    Redondo, Javier [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Max-Planck-Institut fuer Physik, Muenchen (Germany); Ringwald, Andreas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2010-11-15

    Shining light through walls? At first glance this sounds crazy. However, very feeble gravitational and electroweak effects allow for this exotic possibility. Unfortunately, with present and near future technologies the opportunity to observe light shining through walls via these effects is completely out of question. Nevertheless there are quite a number of experimental collaborations around the globe involved in this quest. Why are they doing it? Are there additional ways of sending photons through opaque matter? Indeed, various extensions of the standard model of particle physics predict the existence of new particles called WISPs - extremely weakly interacting slim particles. Photons can convert into these hypothetical particles, which have no problems to penetrate very dense materials, and these can reconvert into photons after their passage - as if light was effectively traversing walls. We review this exciting field of research, describing the most important WISPs, the present and future experiments, the indirect hints from astrophysics and cosmology pointing to the existence of WISPs, and finally outlining the consequences that the discovery of WISPs would have. (orig.)

  4. Microfluidics with fluid walls.

    Science.gov (United States)

    Walsh, Edmond J; Feuerborn, Alexander; Wheeler, James H R; Tan, Ann Na; Durham, William M; Foster, Kevin R; Cook, Peter R

    2017-10-10

    Microfluidics has great potential, but the complexity of fabricating and operating devices has limited its use. Here we describe a method - Freestyle Fluidics - that overcomes many key limitations. In this method, liquids are confined by fluid (not solid) walls. Aqueous circuits with any 2D shape are printed in seconds on plastic or glass Petri dishes; then, interfacial forces pin liquids to substrates, and overlaying an immiscible liquid prevents evaporation. Confining fluid walls are pliant and resilient; they self-heal when liquids are pipetted through them. We drive flow through a wide range of circuits passively by manipulating surface tension and hydrostatic pressure, and actively using external pumps. Finally, we validate the technology with two challenging applications - triggering an inflammatory response in human cells and chemotaxis in bacterial biofilms. This approach provides a powerful and versatile alternative to traditional microfluidics.The complexity of fabricating and operating microfluidic devices limits their use. Walsh et al. describe a method in which circuits are printed as quickly and simply as writing with a pen, and liquids in them are confined by fluid instead of solid walls.

  5. Reliability Considerations for Composite Overwrapped Pressure Vessels on Spacecraft

    Science.gov (United States)

    Murthy, Pappu L. N.; Gyekenyesi, John P.; Grimes-Ledesma, Lorie; Phoenix, S. L.

    2007-01-01

    Composite Overwrapped Pressure Vessels (COPVs) are used to store gases under high pressure onboard spacecraft. These are used for a variety of purposes such as propelling liquid fuel etc, Kevlar, glass, Carbon and other more recent fibers have all been in use to overwrap the vessels. COPVs usually have a thin metallic liner with the primary purpose of containing the gases and prevent any leakage. The liner is overwrapped with filament wound composite such as Kevlar, Carbon or Glass fiber. Although the liner is required to perform in the leak before break mode making the failure a relatively benign mode, the overwrap can fail catastrophically under sustained load due to stress rupture. It is this failure mode that is of major concern as the stored energy of such vessels is often great enough ta cause loss of crew and vehicle. The present paper addresses some of the reliability concerns associated specifically with Kevlar Composite Overwrapped Pressure Vessels. The primary focus of the paper is on how reliability of COPV's are established for the purpose of deciding in general their flight worthiness and continued use. Analytical models based on existing design data will be presented showing how to achieve the required reliability metric to the end of a specific period of performance. Uncertainties in the design parameters and how they affect reliability and confidence intervals will be addressed as well. Some trade studies showing how reliability changes with time during a program period will be presented.

  6. Wall Street som kreationistisk forkynder

    DEFF Research Database (Denmark)

    Ekman, Susanne

    2016-01-01

    Artiklen gennemgår Karen Hos etnografi om Wall Street: "Liquidated: An ethnography of Wall Street" set i lyset af den offentlige debat vedrørende Goldman Sachs opkøb af Dong......Artiklen gennemgår Karen Hos etnografi om Wall Street: "Liquidated: An ethnography of Wall Street" set i lyset af den offentlige debat vedrørende Goldman Sachs opkøb af Dong...

  7. Spontaneous Hemoperitoneum in Pregnancy from a Ruptured Superficial Uterine Vessel

    Directory of Open Access Journals (Sweden)

    Cheng-Yu Wu

    2007-03-01

    Full Text Available A 31-year-old multipara woman pregnant at gestational age 32+ weeks with twins encountered hemoperitoneum resulting from superficial uterine vessel rupture during tocolytic course. The initial presentations were unspecific and sonographic examination was negative. Later the aggravated symptoms led to an impression of abruptio placentae and emergent cesarean section was performed. A superficial venous bleeder was located on the posterior uterine wall and the internal bleeding was up to 3 L. Maternal and fetal outcome were good. Hemoperitoneum during pregnancy is rare but life-threatening to both mother and fetus, and it mimics placenta abruption in many ways. However, by careful investigations with cardiotocogram and bedside echo, they are quite distinguishable. Aggressive fluid replacement and immediate surgical intervention after rapid diagnosis provides the best prognosis.

  8. 15 CFR 970.205 - Vessel safety.

    Science.gov (United States)

    2010-01-01

    ... following: (1) That any foreign flag vessel whose flag state is party to the International Convention for Safety of Life at Sea, 1974 (SOLAS 74) possesses current valid SOLAS 74 certificates; (2) That any foreign flag vessel whose flag state is not party to SOLAS 74 but is party to the International Convention...

  9. Assessing Vessel Traffic Service Operator Situation Awareness

    NARCIS (Netherlands)

    Wiersma, J.W.F.

    2010-01-01

    This thesis describes my study of situation awareness assessment of Vessel Traffic Service (VTS) operators. VTS operators are the traffic controllers on the water. They are responsible for a safe and efficient handling of vessel traffic. They monitor traffic, provide information on request and

  10. Hereditary cerebral small vessel disease and stroke

    DEFF Research Database (Denmark)

    Søndergaard, Christian Baastrup; Nielsen, Jørgen Erik; Hansen, Christine Krarup

    2017-01-01

    Cerebral small vessel disease is considered hereditary in about 5% of patients and is characterized by lacunar infarcts and white matter hyperintensities on MRI. Several monogenic hereditary diseases causing cerebral small vessel disease and stroke have been identified. The purpose of this system...

  11. 33 CFR 401.67 - Explosive vessels.

    Science.gov (United States)

    2010-07-01

    ... TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Dangerous Cargo § 401.67 Explosive vessels. A vessel carrying explosives, either Government or commercial, as defined in the Dangerous Cargo Act of the United States and in the International Maritime Dangerous Goods Code, Class 1, Divisions 1.1 to 1.5 inclusive...

  12. Analyzing Vessel Behavior Using Process Mining

    NARCIS (Netherlands)

    Maggi, F.M.; Mooij, A.J.; Aalst, W.M.P. van der

    2013-01-01

    In the maritime domain, electronic sensors such as AIS receivers and radars collect large amounts of data about the vessels in a certain geographical area. We investigate the use of process mining techniques for analyzing the behavior of the vessels based on these data. In the context of maritime

  13. 78 FR 39649 - Passenger Vessels Accessibility Guidelines

    Science.gov (United States)

    2013-07-02

    ... TRANSPORTATION BARRIERS COMPLIANCE BOARD 36 CFR Part 1196 RIN 3014-AA11 Passenger Vessels Accessibility... Tuesday, June 25, 2013, make the following correction: PART 1196--PASSENGER VESSELS ACCESSIBILITY... ``Figure V703.7.2.1 International Symbol of Accessibility'' and are added to read as set forth below...

  14. Wall morphology, blood flow and wall shear stress: MR findings in patients with peripheral artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Galizia, Mauricio S.; Barker, Alex; Collins, Jeremy; Carr, James [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Liao, Yihua [Northwestern University' s Feinberg School of Medicine, Department of Preventive Medicine, Chicago, IL (United States); McDermott, Mary M. [Northwestern University' s Feinberg School of Medicine, Department of Preventive Medicine, Chicago, IL (United States); Northwestern University' s Feinberg School of Medicine, Department of Medicine, Chicago, IL (United States); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Northwestern University, Department Biomedical Engineering, McCormick School of Engineering, Chicago, IL (United States)

    2014-04-15

    To investigate the influence of atherosclerotic plaques on femoral haemodynamics assessed by two-dimensional (2D) phase-contrast (PC) magnetic resonance imaging (MRI) with three-directional velocity encoding. During 1 year, patients with peripheral artery disease and an ankle brachial index <1.00 were enrolled. After institutional review board approval and written informed consent, 44 patients (age, 70 ± 12 years) underwent common femoral artery MRI. Patients with contra-indications for MRI were excluded. Sequences included 2D time-of-flight, proton-density, T1-weighted and T2-weighted MRI. Electrocardiogram (ECG)-gated 2D PC-MRI with 3D velocity encoding was acquired. A radiologist classified images in five categories. Blood flow, velocity and wall shear stress (WSS) along the vessel circumference were quantified from the PC-MRI data. The acquired images were of good quality for interpretation. There were no image quality problems related to poor ECG-gating or slice positioning. Velocities, oscillatory shear stress and total flow were similar between patients with normal arteries and wall thickening/plaque. Patients with plaques demonstrated regionally increased peak systolic WSS and enhanced WSS eccentricity. Combined multi-contrast morphological imaging of the peripheral arterial wall with PC-MRI with three-directional velocity encoding is a feasible technique. Further study is needed to determine whether flow is an appropriate marker for altered endothelial cell function, vascular remodelling and plaque progression. (orig.)

  15. Build an Interactive Word Wall

    Science.gov (United States)

    Jackson, Julie

    2018-01-01

    Word walls visually display important vocabulary covered during class. Although teachers have often been encouraged to post word walls in their classrooms, little information is available to guide them. This article describes steps science teachers can follow to transform traditional word walls into interactive teaching tools. It also describes a…

  16. Molded Concrete Center Mine Wall

    Science.gov (United States)

    Lewis, E. V.

    1987-01-01

    Proposed semiautomatic system forms concrete-foam wall along middle of coal-mine passage. Wall helps support roof and divides passage into two conduits needed for ventilation of coal face. Mobile mold and concrete-foam generator form sections of wall in place.

  17. Indoor climbing walls in Prague

    OpenAIRE

    Schwarzová, Veronika

    2012-01-01

    This work presents the indoor climbing walls in climbing centers for the public in Prague. It creates an overview of qualitative and quantitative characteristics of indoor climbing walls in Prague. Thesis allowing ordinary users and the general public interested in climbing easier selection of the appropriate climbing wall according on their level, the safety requirements, background, but also the place of residence.

  18. Angiogenesis and blood vessel stability in inflammatory arthritis.

    LENUS (Irish Health Repository)

    Kennedy, Aisling

    2012-02-01

    OBJECTIVE: To assess blood vessel stability in inflammatory synovial tissue (ST) and to examine neural cell adhesion molecule (NCAM), oxidative DNA damage, and hypoxia in vivo. METHODS: Macroscopic vascularity and ST oxygen levels were determined in vivo in patients with inflammatory arthritis who were undergoing arthroscopy. Vessel maturity\\/stability was quantified in matched ST samples by dual immunofluorescence staining for factor VIII (FVIII)\\/alpha-smooth muscle actin (alpha-SMA). NCAM and 8-oxo-7,8-dihydro-2\\'-deoxyguanosine (8-oxodG) were examined by immunohistochemistry. Angiogenesis was assessed in vitro, using human dermal endothelial cells (HDECs) in a Matrigel tube formation assay. RESULTS: A significant number of immature vessels (showing no pericyte recruitment) was observed in tissue from patients with inflammatory arthritis (P < 0.001), in contrast to osteoarthritic and normal tissue, which showed complete recruitment of pericytes. Low in vivo PO(2) levels in the inflamed joint (median [range] 22.8 [3.2-54.1] mm Hg) were inversely related to increased macroscopic vascularity (P < 0.04) and increased microscopic expression of FVIII and alpha-SMA (P < 0.04 and P < 0.03, respectively). A significant proportion of vessels showed focal expression of NCAM and strong nuclear 8-oxodG expression, implicating a loss of EC-pericyte contact and increased DNA damage, levels of which were inversely associated with low in vivo PO(2) (P = 0.04 for each comparison). Circulating cells were completely negative for 8-oxodG. Exposure of HDEC to 3% O(2) (reflecting mean ST in vivo measurements) significantly increased EC tube formation (P < 0.05). CONCLUSION: Our findings indicate the presence of unstable vessels in inflamed joints associated with hypoxia, incomplete EC-pericyte interactions, and increased DNA damage. These changes may further contribute to persistent hypoxia in the inflamed joint to further drive this unstable microenvironment.

  19. Pulmonary vein and atrial wall pathology in human total anomalous pulmonary venous connection

    NARCIS (Netherlands)

    Douglas, Yvonne L.; Jongbloed, Monique R. M.; den Hartog, Wietske C. E.; Bartelings, Margot M.; Bogers, Ad J. J. C.; Ebels, Tjark; DeRuiter, Marco C.; Gittenberger-de Groot, Adriana C.

    2009-01-01

    Background: Normally, the inside of the left atrial (LA) body and pulmonary veins (PVs) is lined by vessel wall tissue covered by myocardium. In total anomalous pulmonary venous connection (TAPVC), no connection of the PVs with the LA body exists. These veins have an increased incidence of PV

  20. Endoluminal compression clip : full-thickness resection of the mesenteric bowel wall in a porcine model

    NARCIS (Netherlands)

    Kopelman, Yael; Siersema, Peter D.; Nir, Yael; Szold, Amir; Bapaye, Amol; Segol, Ori; Willenz, Ehud P.; Lelcuk, Shlomo; Geller, Alexander; Kopelman, Doron

    2009-01-01

    Background: Performing a full-thickness intestinal wall resection Of a sessile polyp located on the mesenteric side with a compression clip may lead to compression of mesenteric vessels. The application of such a clip may therefore cause a compromised blood supply in the particular bowel segment,