Comparison between MDCT and Grayscale IVUS in a Quantitative Analysis of Coronary Lumen in Segments with or without Atherosclerotic Plaques

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Falcão, João L. A. A.; Falcão, Breno A. A. [Heart Institute (InCor), University of São Paulo Medical School (USP), São Paulo, SP (Brazil); Gurudevan, Swaminatha V. [Cedars-Sinai Heart Institute, Los Angeles, California, USA (United States); Campos, Carlos M.; Silva, Expedito R.; Kalil-Filho, Roberto; Rochitte, Carlos E.; Shiozaki, Afonso A.; Coelho-Filho, Otavio R.; Lemos, Pedro A. [Heart Institute (InCor), University of São Paulo Medical School (USP), São Paulo, SP (Brazil)

2015-04-15

The diagnostic accuracy of 64-slice MDCT in comparison with IVUS has been poorly described and is mainly restricted to reports analyzing segments with documented atherosclerotic plaques. We compared 64-slice multidetector computed tomography (MDCT) with gray scale intravascular ultrasound (IVUS) for the evaluation of coronary lumen dimensions in the context of a comprehensive analysis, including segments with absent or mild disease. The 64-slice MDCT was performed within 72 h before the IVUS imaging, which was obtained for at least one coronary, regardless of the presence of luminal stenosis at angiography. A total of 21 patients were included, with 70 imaged vessels (total length 114.6 ± 38.3 mm per patient). A coronary plaque was diagnosed in segments with plaque burden > 40%. At patient, vessel, and segment levels, average lumen area, minimal lumen area, and minimal lumen diameter were highly correlated between IVUS and 64-slice MDCT (p < 0.01). However, 64-slice MDCT tended to underestimate the lumen size with a relatively wide dispersion of the differences. The comparison between 64-slice MDCT and IVUS lumen measurements was not substantially affected by the presence or absence of an underlying plaque. In addition, 64-slice MDCT showed good global accuracy for the detection of IVUS parameters associated with flow-limiting lesions. In a comprehensive, multi-territory, and whole-artery analysis, the assessment of coronary lumen by 64-slice MDCT compared with coronary IVUS showed a good overall diagnostic ability, regardless of the presence or absence of underlying atherosclerotic plaques.

Estimation of center line and diameter of brain blood vessel using three-dimensional blood vessel matching method with head three-dimensional CTA image

International Nuclear Information System (INIS)

Maekawa, Masashi; Shinohara, Toshihiro; Nakayama, Masato; Nakasako, Noboru

2010-01-01

To support and automate the brain blood vessel disease diagnosis, a novel method to obtain the center line and the diameter of a blood vessel is proposed with a three-dimensional head computed tomographic angiography (CTA) image. Although the line thinning processing with distance transform or gray information is generally used to obtain the blood vessel center line, this method is not essentially one to obtain the center line and tends to yield extra lines depending on CTA images. In this study, the center line of the blood vessel is obtained by tracing the vessel. The blood vessel is traced by sequentially estimating the center point and direction of the blood vessel. The center point and direction of the blood vessel are estimated by taking the correlation between the blood vessel and a solid model of the blood vessel that is designed by considering noise influence. In addition, the vessel diameter is also estimated by correlating the blood vessel and the blood vessel model of which the diameter is variable. The validity of the proposed method is confirmed by experimentally applied the proposed method to an actual three-dimensional head CTA image. (author)

Spectral Imaging for Intracranial Stents and Stent Lumen.

Science.gov (United States)

Weng, Chi-Lun; Tseng, Ying-Chi; Chen, David Yen-Ting; Chen, Chi-Jen; Hsu, Hui-Ling

2016-01-01

Application of computed tomography for monitoring intracranial stents is limited because of stent-related artifacts. Our purpose was to evaluate the effect of gemstone spectral imaging on the intracranial stent and stent lumen. In vitro, we scanned Enterprise stent phantom and a stent-cheese complex using the gemstone spectral imaging protocol. Follow-up gemstone spectral images of 15 consecutive patients with placement of Enterprise from January 2013 to September 2014 were also retrospectively reviewed. We used 70-keV, 140-keV, iodine (water), iodine (calcium), and iodine (hydroxyapatite) images to evaluate their effect on the intracranial stent and stent lumen. Two regions of interest were individually placed in stent lumen and adjacent brain tissue. Contrast-to-noise ratio was measured to determine image quality. The maximal diameter of stent markers was also measured to evaluate stent-related artifact. Two radiologists independently graded the visibility of the lumen at the maker location by using a 4-point scale. The mean of grading score, contrast/noise ratio and maximal diameter of stent markers were compared among all modes. All results were analyzed by SPSS version 20. In vitro, iodine (water) images decreased metallic artifact of stent makers to the greatest degree. The most areas of cheese were observed on iodine (water) images. In vivo, iodine (water) images had the smallest average diameter of stent markers (0.33 ± 0.17mm; P stent lumen (160.03 ±37.79; P stent-related artifacts of Enterprise and enhance contrast of in-stent lumen. Spectral imaging may be considered a noninvasive modality for following-up patients with in-stent stenosis.

Dependence of light scattering profile in tissue on blood vessel diameter and distribution: a computer simulation study.

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Duadi, Hamootal; Fixler, Dror; Popovtzer, Rachela

2013-11-01

Most methods for measuring light-tissue interactions focus on the volume reflectance while very few measure the transmission. We investigate both diffusion reflection and diffuse transmission at all exit angles to receive the full scattering profile. We also investigate the influence of blood vessel diameter on the scattering profile of a circular tissue. The photon propagation path at a wavelength of 850 nm is calculated from the absorption and scattering constants via Monte Carlo simulation. Several simulations are performed where a different vessel diameter and location were chosen but the blood volume was kept constant. The fraction of photons exiting the tissue at several central angles is presented for each vessel diameter. The main result is that there is a central angle that below which the photon transmission decreased for lower vessel diameters while above this angle the opposite occurred. We find this central angle to be 135 deg for a two-dimensional 10-mm diameter circular tissue cross-section containing blood vessels. These findings can be useful for monitoring blood perfusion and oxygen delivery in the ear lobe and pinched tissues. © 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)

Automatic evaluation of vessel diameter variation from 2D X-ray angiography.

Science.gov (United States)

M'hiri, Faten; Duong, Luc; Desrosiers, Christian; Dahdah, Nagib; Miró, Joaquim; Cheriet, Mohamed

2017-11-01

Early detection of blood vessel pathologies can be made through the evaluation of functional and structural abnormalities in the arteries, including the arterial distensibility measure. We propose a feasibility study on computing arterial distensibility automatically from monoplane 2D X-ray sequences for both small arteries (such as coronary arteries) and larger arteries (such as the aorta). To compute the distensibility measure, three steps were developed: First, the segment of an artery is extracted using our graph-based segmentation method. Then, the same segment is tracked in the moving sequence using our spatio-temporal segmentation method: the Temporal Vessel Walker. Finally, the diameter of the artery is measured automatically at each frame of the sequence based on the segmentation results. The method was evaluated using one simulated sequence and 4 patients' angiograms depicting the coronary arteries and three depicting the ascending aorta. Results of the simulated sequence achieved a Dice index of 98%, with a mean squared error in diameter measurement of [Formula: see text] mm. Results obtained from patients' X-ray sequences are consistent with manual assessment of the diameter by experts. The proposed method measures changes in diameter of a specific segment of a blood vessel during the cardiac sequence, automatically based on monoplane 2D X-ray sequence. Such information might become a key to help physicians in the detection of variations of arterial stiffness associated with early stages of various vasculopathies.

Enlargement of halloysite clay nanotube lumen by selective etching of aluminum oxide.

Science.gov (United States)

Abdullayev, Elshad; Joshi, Anupam; Wei, Wenbo; Zhao, Yafei; Lvov, Yuri

2012-08-28

Halloysite clay tubes have 50 nm diameter and chemically different inner and outer walls (inner surface of aluminum oxide and outer surface of silica). Due to this different chemistry, the selective etching of alumina from inside the tube was realized, while preserving their external diameter (lumen diameter changed from 15 to 25 nm). This increases 2-3 times the tube lumen capacity for loading and further sustained release of active chemical agents such as metals, corrosion inhibitors, and drugs. In particular, halloysite loading efficiency for the benzotriazole increased 4 times by selective etching of 60% alumina within the tubes' lumens. Specific surface area of the tubes increased over 6 times, from 40 to 250 m(2)/g, upon acid treatment.

The design of lifting attachments for the erection of large diameter and heavy wall pressure vessels

International Nuclear Information System (INIS)

Antalffy, Leslie P.; Miller, George A.; Kirkpatrick, Kenneth D.; Rajguru, Anil; Zhu, Yong

2016-01-01

Lifting attachments for the erection of large diameter and heavy wall pressure vessels require special consideration to ensure that their attachment to their vessel shells or heads do not overstress the vessel during the erection process when lifting these from grade onto their respective foundations. Today, in refinery and petrochemical services, large diameter vessels with diameters ranging up to 15 m and reactors with lifting weights in the range of 700–1400 tons are not uncommon. In today's fabrication market, these vessels may be purchased and fabricated in shops dispersed globally and will require unique equipment for their safe handling, transportation and subsequent erection. The challenge is to design the lifting attachments in such a manner that the attachments provide a safe, cost effective and effective solution based upon the limitations of the job site lift equipment available for erection. Such equipment for the transportation and subsequent lifting of large diameter and heavy wall pressure equipment is usually scarce and quite expensive. Planning ahead, well in advance of the lift date is almost a mandatory requirement. Usually, the specific parameters of the vessel to be lifted and the lifting equipment available at the site will dictate the type of lifting attachments to be designed for the vessel. Once the type of vessel attachment has been chosen, careful consideration must be given to the design of attachments to the pressure vessel in consideration to ensure that the vessel and lifting components are not overstressed during the lifting process. The paper also discusses different types of lifting attachments that may be attached to each end of the vessel either by bolting or welding and discusses the pros and cons of each. The paper also provides an example of a finite element analysis (FEA) of a top nozzle, a FEA of a pair of lifting trunnions and a FEA of welded on lifting lugs for buried pipe. The purpose of the paper is to outline the

Evaluation of an improved technique for automated center lumen line definition in cardiovascular image data

International Nuclear Information System (INIS)

Gratama van Andel, Hugo A.F.; Meijering, Erik; Vrooman, Henri A.; Stokking, Rik; Lugt, Aad van der; Monye, Cecile de

2006-01-01

The aim of the study was to evaluate a new method for automated definition of a center lumen line in vessels in cardiovascular image data. This method, called VAMPIRE, is based on improved detection of vessel-like structures. A multiobserver evaluation study was conducted involving 40 tracings in clinical CTA data of carotid arteries to compare VAMPIRE with an established technique. This comparison showed that VAMPIRE yields considerably more successful tracings and improved handling of stenosis, calcifications, multiple vessels, and nearby bone structures. We conclude that VAMPIRE is highly suitable for automated definition of center lumen lines in vessels in cardiovascular image data. (orig.)

Visual function and retinal vessel diameters during hyperthermia in man

DEFF Research Database (Denmark)

Jensen, Bettina Hagström; Bram, Thue; Kappelgaard, Per

2017-01-01

.01), a 10.6-mmHg mean reduction in diastolic blood pressure (p vein...... laser ophthalmoscopy was used to measure retinal trunk vessel diameters. Assessment was made at baseline, during hyperthermia and after cooling. RESULTS: The induction of a mean increase in core body temperature of 1.02°C was associated with a 7.15-mmHg mean reduction in systolic blood pressure (p

Vascular diameter measurement in CT angiography: comparison of model-based iterative reconstruction and standard filtered back projection algorithms in vitro.

Science.gov (United States)

Suzuki, Shigeru; Machida, Haruhiko; Tanaka, Isao; Ueno, Eiko

2013-03-01

The purpose of this study was to evaluate the performance of model-based iterative reconstruction (MBIR) in measurement of the inner diameter of models of blood vessels and compare performance between MBIR and a standard filtered back projection (FBP) algorithm. Vascular models with wall thicknesses of 0.5, 1.0, and 1.5 mm were scanned with a 64-MDCT unit and densities of contrast material yielding 275, 396, and 542 HU. Images were reconstructed images by MBIR and FBP, and the mean diameter of each model vessel was measured by software automation. Twenty separate measurements were repeated for each vessel, and variance among the repeated measures was analyzed for determination of measurement error. For all nine model vessels, CT attenuation profiles were compared along a line passing through the luminal center on axial images reconstructed with FBP and MBIR, and the 10-90% edge rise distances at the boundary between the vascular wall and the lumen were evaluated. For images reconstructed with FBP, measurement errors were smallest for models with 1.5-mm wall thickness, except those filled with 275-HU contrast material, and errors grew as the density of the contrast material decreased. Measurement errors with MBIR were comparable to or less than those with FBP. In CT attenuation profiles of images reconstructed with MBIR, the 10-90% edge rise distances at the boundary between the lumen and vascular wall were relatively short for each vascular model compared with those of the profile curves of FBP images. MBIR is better than standard FBP for reducing reconstruction blur and improving the accuracy of diameter measurement at CT angiography.

Pulmonary artery pulsatility and effect on vessel diameter assessment in magnetic resonance imaging

International Nuclear Information System (INIS)

Shariat, Masoud; Schantz, Daryl; Yoo, Shi-Joon; Wintersperger, Bernd J.; Seed, Mike; Alnafisi, Bahiyah; Chu, Leysia; MacGowan, Christopher K.; Amerom, Joshua van; Grosse-Wortmann, Lars

2014-01-01

Background: Information about thoracic vascular sizes can crucially affect clinical decision-making in cardiovascular disease. A variety of imaging techniques such as catheter angiography, contrast enhanced computed tomography (CT) and cardiac magnetic resonance imaging (CMR) are routinely used to measure vascular diameters. Traditionally, CMR black blood sequences were the main anatomical tool for visualization of vascular anatomy and still are in many centers. More recently, the vessel diameters are measured on multiplanar reconstructions derived from static magnetic resonance angiography (MRA). This study was performed to investigate the variation of vessel diameter measurements on different CMR techniques with respect to their data acquisition scheme. Methods: We recruited two groups of patients for this prospective study. One group included patients with repaired tetralogy of Fallot (TOF), with at least moderate pulmonary insufficiency and another group of patients who underwent CMR as part of a diagnostic work-up for arrhythmogenic right ventricular cardiomyopathy (ARVC). Additional images of the right pulmonary artery (RPA) were acquired in the double inversion recovery (DIR) black blood, cine steady state free precession (SSFP) and MRA. All images were reviewed by two CMR trained readers using the electronic caliper provided within the picture archiving and communication system package. The maximum diameter of each artery was recorded in millimeters with up to one decimal point. Paired t-tests and Bland–Altman plots were used for comparison of measurements between different sequences. Results: A total of 52 patients were recruited for this study, 26 patients in the TOF group (15 males, age 12.55 ± 2.9) and 26 patients in the ARVC group (15 males, age 15.6 ± 2.3). In both groups, the RPA sizes were not significantly different between the DIR images and diastolic cine SSFP (p > 0.05). Measurements on DIR were significantly smaller than those made on

Pulmonary artery pulsatility and effect on vessel diameter assessment in magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Shariat, Masoud, E-mail: masoudshariat@gmail.com [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Schantz, Daryl, E-mail: daryl.schantz@gmail.com [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Yoo, Shi-Joon, E-mail: shi-joon.yoo@sickkids.ca [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Wintersperger, Bernd J., E-mail: bernd.wintersperger@uhn.ca [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Seed, Mike, E-mail: mike.seed@sickkids.ca [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Department of Cardiology, Hospital for Sick Children, Toronto, Ontario (Canada); Alnafisi, Bahiyah, E-mail: bahiyah.alnafisi@uhn.ca [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Chu, Leysia, E-mail: leysia_99@yahoo.com [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); MacGowan, Christopher K., E-mail: christopher.macgowan@sickkids.ca [Department of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, Ontario (Canada); Amerom, Joshua van, E-mail: Joshu.vanamerom@sickkids.ca [Department of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, Ontario (Canada); Grosse-Wortmann, Lars, E-mail: lars.grosse-wortmann@sickkids.ca [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Department of Cardiology, Hospital for Sick Children, Toronto, Ontario (Canada)

2014-02-15

Background: Information about thoracic vascular sizes can crucially affect clinical decision-making in cardiovascular disease. A variety of imaging techniques such as catheter angiography, contrast enhanced computed tomography (CT) and cardiac magnetic resonance imaging (CMR) are routinely used to measure vascular diameters. Traditionally, CMR black blood sequences were the main anatomical tool for visualization of vascular anatomy and still are in many centers. More recently, the vessel diameters are measured on multiplanar reconstructions derived from static magnetic resonance angiography (MRA). This study was performed to investigate the variation of vessel diameter measurements on different CMR techniques with respect to their data acquisition scheme. Methods: We recruited two groups of patients for this prospective study. One group included patients with repaired tetralogy of Fallot (TOF), with at least moderate pulmonary insufficiency and another group of patients who underwent CMR as part of a diagnostic work-up for arrhythmogenic right ventricular cardiomyopathy (ARVC). Additional images of the right pulmonary artery (RPA) were acquired in the double inversion recovery (DIR) black blood, cine steady state free precession (SSFP) and MRA. All images were reviewed by two CMR trained readers using the electronic caliper provided within the picture archiving and communication system package. The maximum diameter of each artery was recorded in millimeters with up to one decimal point. Paired t-tests and Bland–Altman plots were used for comparison of measurements between different sequences. Results: A total of 52 patients were recruited for this study, 26 patients in the TOF group (15 males, age 12.55 ± 2.9) and 26 patients in the ARVC group (15 males, age 15.6 ± 2.3). In both groups, the RPA sizes were not significantly different between the DIR images and diastolic cine SSFP (p > 0.05). Measurements on DIR were significantly smaller than those made on

Does Physical Fitness Buffer the Relationship between Psychosocial Stress, Retinal Vessel Diameters, and Blood Pressure among Primary Schoolchildren?

Science.gov (United States)

Endes, Katharina; Herrmann, Christian; Colledge, Flora; Brand, Serge; Donath, Lars; Faude, Oliver; Pühse, Uwe; Hanssen, Henner; Zahner, Lukas

2016-01-01

Background. Strong evidence exists showing that psychosocial stress plays an important part in the development of cardiovascular diseases. Because physical inactivity is associated with less favourable retinal vessel diameter and blood pressure profiles, this study explores whether physical fitness is able to buffer the negative effects of psychosocial stress on retinal vessel diameters and blood pressure in young children. Methods. 325 primary schoolchildren (51% girls, Mage = 7.28 years) took part in this cross-sectional research project. Retinal arteriolar diameters, retinal venular diameters, arteriolar to venular ratio, and systolic and diastolic blood pressure were assessed in all children. Interactions terms between physical fitness (performance in the 20 m shuttle run test) and four indicators of psychosocial stress (parental reports of critical life events, family, peer and school stress) were tested in a series of hierarchical regression analyses. Results. Critical life events and family, peer, and school-related stress were only weakly associated with retinal vessel diameters and blood pressure. No support was found for a stress-buffering effect of physical fitness. Conclusion. More research is needed with different age groups to find out if and from what age physical fitness can protect against arteriolar vessel narrowing and the occurrence of other cardiovascular disease risk factors. PMID:27795958

Estimation of vessel diameter and blood flow dynamics from laser speckle images

DEFF Research Database (Denmark)

Postnov, Dmitry D.; Tuchin, Valery V.; Sosnovtseva, Olga

2016-01-01

Laser speckle imaging is a rapidly developing method to study changes of blood velocity in the vascular networks. However, to assess blood flow and vascular responses it is crucial to measure vessel diameter in addition to blood velocity dynamics. We suggest an algorithm that allows for dynamical...

Quantitative measurement of changes in retinal vessel diameter in ocular fundus images

DEFF Research Database (Denmark)

Pedersen, Lars; Grunkin, Michael; Ersbøll, Bjarne Kjær

2000-01-01

The change in diameter of retinal vessels as a function of increasing distance to the optic disc is believed to be indicative of the risk level of various vascular diseases such as generalised arteriosclerosis and Diabetes Mellitus. In particular, focal arteriolar narrowing (FAN) is considered re...

Relationship between retinal vessel diameters and retinopathy in the Inter99 Eye Study

DEFF Research Database (Denmark)

Drobnjak, Dragana; Munch, Inger Christine; Glümer, Charlotte

2017-01-01

PURPOSE: To examine the association between retinal vessel diameters and retinopathy in participants with and without type 2 diabetes in a Danish population-based cohort. METHODS: The study included 878 persons aged 30 to 60 years from the Inter99 Eye Study. Retinopathy was defined as a presence...... was 6.3 µm (CI 95%: 1.0 to 11.6, p = 0.020) wider and CRVE was 7.9 µm (CI 95%: 0.7 to 15.2, p = 0.030) wider in those with retinopathy compared to those without retinopathy, after adjusting for age, gender, HbA1c, blood pressure, smoking, serum total and HDL cholesterol. In all participants, CRAE.......001), and decreased with higher HDL cholesterol (p gender was associated with wider CRVE (p = 0.029). CONCLUSIONS: Wider retinal vessel diameters were associated with the presence of retinopathy in participants with diabetes, but not in participants without diabetes...

Classic beta-amyloid deposits cluster around large diameter blood vessels rather than capillaries in sporadic Alzheimer's disease.

Science.gov (United States)

Armstrong, Richard A

2006-11-01

Various hypotheses could explain the relationship between beta-amyloid (Abeta) deposition and the vasculature in Alzheimer's disease (AD). Amyloid deposition may reduce capillary density, affect endothelial cells of blood vessels, result in diffusion from blood vessels, or interfere with the perivascular clearance mechanism. Hence, the spatial pattern of the classic ('cored') type of Abeta deposit was studied in the upper laminae (I,II/III) of the superior frontal gyrus in nine cases of sporadic AD (SAD). Sections were immunostained with antibodies against Abeta and with collagen IV to study the relationships between the spatial distribution of the classic deposits and the blood vessel profiles. Both the classic deposits and blood vessel profiles were distributed in clusters. In all cases, there was a positive spatial correlation between the clusters of the classic deposits and the larger diameter (>10 microm) blood vessel profiles and especially the vertically penetrating arterioles. In only 1 case, was there a significant spatial correlation between the clusters of the classic deposits and the smaller diameter (upper laminae of the frontal cortex. This aggregation could result from diffusion of proteins from blood vessels or from overloading the system of perivascular clearance from the brain.

MRT of carotid stents: influence of stent properties and sequence parameters on visualization of the carotid artery lumen

International Nuclear Information System (INIS)

Straube, T.; Wolf, S.; Alfke, K.; Jansen, O.; Flesser, A.; Deli, M.; Nabavi, A.

2005-01-01

Purpose: To evaluate MR artifacts of carotid artery stents and to optimize stent properties and sequence parameters. Material and Methods: Four carotid artery stents - Wallstent (mediloy), Precise (nitinol), ACCULINK (nitinol) and a stent prototype (nitinol) - were investigated in a flow model of the cervical vessels. The model was made of silicon tubing and a flow pump that produces realistic flow curves of the carotid artery. To investigate the effects of magnetic susceptibility and radiofrequency induced shielding artifacts, turbo spin echo and gradient echo sequences as well as CE-MRAs were measured. To improve the visualization of the stent lumen in a CE-MRA, flip angle as well as geometry and covering of the stent prototype were altered. Results: Susceptibility artifacts in stents of the carotid artery only influence the lumen visualization at the proximal and distal end of the braided mediloy stent. A change of stent coverings has no significant influence on radiofrequency artifacts, whereas a reduction in linking elements between stent segments and a change in diameter of stent struts improves visualization of the stent lumen. By increasing the flip angle in a CE-MRA, visualization of the stent lumen is possible in both mediloy and nitinol stents. Conclusion: The choice of stent material and changes in stent geometry as well as the optimization of the flip angle of the CE-MRA may reduce susceptibility and radiofrequency artifacts, rendering feasible the CE-MRA of a stented carotid artery. (orig.)

Effects of cryopreservation on excretory function, cellular adhesion molecules and vessel lumen formation in human umbilical vein endothelial cells.

Science.gov (United States)

Cai, Guoping; Lai, Binbin; Hong, Huaxing; Lin, Peng; Chen, Weifu; Zhu, Zhong; Chen, Haixiao

2017-07-01

Cryopreservation is widely used in regenerative medicine for tissue preservation. In the present study, the effects of cryopreservation on excretory function, cellular adhesion molecules and vessel lumen formation in human umbilical vein endothelial cells (HUVECs) were investigated. After 0, 4, 8, 12 or 24 weeks of cryopreservation in liquid nitrogen, the HUVECs were thawed. The excretory functions markers (endothelin‑1, prostaglandin E1, von Willebrand factor and nitric oxide) of HUVECs were measured by ELISA assay. The expression of intercellular adhesion molecule‑1 (ICAM‑1) in HUVECs was analyzed using flow cytometry. An angiogenesis assay was used to determine the angiogeneic capabilities of the thawed HUVECs. The results demonstrated that cryopreserved/thawed and recultivated HUVECs were unsuitable for tissue‑engineered microvascular construction. Specifically, the excretory function of the cells was significantly decreased in the post‑cryopreserved HUVECs at 24 weeks. In addition, the level of ICAM‑1 in HUVECs was significantly upregulated from the fourth week of cryopreservation. Furthermore, the tube‑like structure‑forming potential was weakened with increasing cryopreservation duration, and the numbers of lumen and the length of the pipeline were decreased in the thawed HUVECs, in a time‑dependent manner. In conclusion, the results of the present study revealed that prolonged cryopreservation may lead to HUVEC dysfunction and did not create stable cell lines for tissue‑engineered microvascular construction.

A novel lumen-apposing metal stent for endoscopic ultrasound-guided drainage of pancreatic fluid collections

DEFF Research Database (Denmark)

Walter, Daisy; Will, Uwe; Sanchez-Yague, Andres

2015-01-01

BACKGROUND AND STUDY AIMS: A novel large-diameter, lumen-apposing, self-expanding metal stent with bilateral flanges was recently developed for endoscopic ultrasound (EUS)-guided transmural drainage of symptomatic pancreatic fluid collections (PFCs). The aim of this study was to evaluate the effi......BACKGROUND AND STUDY AIMS: A novel large-diameter, lumen-apposing, self-expanding metal stent with bilateral flanges was recently developed for endoscopic ultrasound (EUS)-guided transmural drainage of symptomatic pancreatic fluid collections (PFCs). The aim of this study was to evaluate...

The dimensional changes of a 24 inch diameter vessel during a campaign of successive glass making runs

International Nuclear Information System (INIS)

Chidley, B.E.

1983-01-01

Throughout the life of a 24 inch diameter Glass Making Vessel used on the inactive Harvest Vitrification Plant dimensional measurements have been recorded. When glass is present the diameter increases due to thermal stresses. Some permanent longitudinal extension (about 1%) occurred over the 20 runs comprising the glass-making campaign. (author)

Rationale and design of the East-West late lumen loss study: Comparison of late lumen loss between Eastern and Western drug-eluting stent study cohorts.

Science.gov (United States)

Harrison, Robert W; Radhakrishnan, Vaishnavi; Lam, Peter S; Allocco, Dominic J; Brar, Sandeep; Fahy, Martin; Fisher, Rebecca; Ikeno, Fumiaki; Généreux, Philippe; Kimura, Takeshi; Liu, Minglei; Lye, Weng Kit; Mintz, Gary S; Nagai, Hirofumi; Suzuki, Yuka; White, Roseann; Allen, John C; Krucoff, Mitchell W

2016-12-01

The contemporary evaluation of novel drug-eluting stents (DES) includes mechanistic observations that characterize postdeployment stent behavior. Quantification of late lumen loss due to neointimal hyperplasia 8-13 months after stent implantation, via quantitative coronary angiography (QCA), constitutes such an observation and is required by most regulatory authorities. Late lumen loss, as determined by QCA, has been validated as a surrogate for clinical endpoints such as target vessel revascularization. The mechanistic response to DES has not been directly compared across predominantly Asian or Western populations, whereas understanding their comparability across geographic populations could enhance global DES evaluation. The East-West late lumen loss study is designed to demonstrate whether the residual differences in late lumen loss, as assessed by QCA, is different between Eastern and Western DES recipients from studies with protocol angiography at 8-13 months of follow-up. Data from independent core laboratories that have characterized angiographic late lumen loss in DES clinical trials with protocol follow-up angiography will be compiled and dichotomized into Eastern and Western populations. A prospectively developed propensity score model incorporating clinical and anatomic variables affecting late lumen loss will be used to adjust comparisons of QCA measurements. Documentation of whether there are clinically meaningful differences in mechanistic response to DES implantation across genetically unique geographies could facilitate both the quality and efficiency of global device evaluation requiring invasive follow-up for novel stent designs. Copyright © 2016 Elsevier Inc. All rights reserved.

Turbulent flow in a vessel agitated by side entering inclined blade turbine with different diameter using CFD simulation

Science.gov (United States)

Fathonah, N. N.; Nurtono, T.; Kusdianto; Winardi, S.

2018-03-01

Single phase turbulent flow in a vessel agitated by side entering inclined blade turbine has simulated using CFD. The aim of this work is to identify the hydrodynamic characteristics of a model vessel, which geometrical configuration is adopted at industrial scale. The laboratory scale model vessel is a flat bottomed cylindrical tank agitated by side entering 4-blade inclined blade turbine with impeller rotational speed N=100-400 rpm. The effect of the impeller diameter on fluid flow pattern has been investigated. The fluid flow patterns in a vessel is essentially characterized by the phenomena of macro-instabilities, i.e. the flow patterns change with large scale in space and low frequency. The intensity of fluid flow in the tank increase with the increase of impeller rotational speed from 100, 200, 300, and 400 rpm. It was accompanied by shifting the position of the core of circulation flow away from impeller discharge stream and approached the front of the tank wall. The intensity of fluid flow in the vessel increase with the increase of the impeller diameter from d=3 cm to d=4 cm.

Linear-regression convolutional neural network for fully automated coronary lumen segmentation in intravascular optical coherence tomography

Science.gov (United States)

Yong, Yan Ling; Tan, Li Kuo; McLaughlin, Robert A.; Chee, Kok Han; Liew, Yih Miin

2017-12-01

Intravascular optical coherence tomography (OCT) is an optical imaging modality commonly used in the assessment of coronary artery diseases during percutaneous coronary intervention. Manual segmentation to assess luminal stenosis from OCT pullback scans is challenging and time consuming. We propose a linear-regression convolutional neural network to automatically perform vessel lumen segmentation, parameterized in terms of radial distances from the catheter centroid in polar space. Benchmarked against gold-standard manual segmentation, our proposed algorithm achieves average locational accuracy of the vessel wall of 22 microns, and 0.985 and 0.970 in Dice coefficient and Jaccard similarity index, respectively. The average absolute error of luminal area estimation is 1.38%. The processing rate is 40.6 ms per image, suggesting the potential to be incorporated into a clinical workflow and to provide quantitative assessment of vessel lumen in an intraoperative time frame.

A nonimaging catheter for measurement of coronary artery lumen area: a first in man pilot study.

Science.gov (United States)

Hermiller, James; Choy, Jenny S; Svendsen, Mark; Bigelow, Brian; Fouts, Andrew M; Hall, Jack; Parr, Kirk; Ball, Michael; Sinha, Anjan; Bhatt, Deepak L; Kassab, Ghassan S

2011-08-01

The objective of this human pilot study was to determine the safety and the level of agreement between a novel nonimaging 2.7 Fr. catheter-based system (LumenRECON, LR) that uses electrical conductance for measurement of lumen cross-sectional area (CSA) with intravascular ultrasound (IVUS) and quantitative coronary angiography (QCA). Based on previous animal studies, we hypothesized the level of agreement between LR and IVUS to be 13%. Accurate and reproducible vessel sizing is essential for optimal percutaneous coronary intervention (PCI). A total of 12 patients were studied to evaluate the safety, accuracy, and reproducibility of the system in comparison with IVUS and QCA. The CSA of coronary arteries was determined by IVUS, QCA, and LR in the distal, proximal, and center of a lesion during standard PCI. A Bland-Altman plot of the LR versus IVUS and QCA show a nonsignificant mean difference between the two measurements of 0.04 and 0.07 mm in diameter, respectively. The root mean square error of LR versus IVUS and QCA was 14.3 and 25.8% of the mean IVUS or QCA diameter, respectively. The mean of the difference between two LR duplicate measurements was nearly zero (0.03 mm) and the repeatability coefficient was within 8.7% of the mean of the two measurements. There were no procedural complications nor were any device-related MACE reported within 30 days of the procedure. This proof of concept pilot study establishes the safety and accuracy of the conductance technology for a pivotal trial of coronary sizing. Copyright © 2011 Wiley-Liss, Inc.

Non-gated vessel wall imaging of the internal carotid artery using radial scanning and fast spin echo sequence. Evaluation of vessel signal intensity by flow rate at 3.0 tesla

International Nuclear Information System (INIS)

Nakamura, Manami; Makabe, Takeshi; Ichikawa, Masaki; Hatakeyama, Ryohei; Sugimori, Hiroyuki; Sakata, Motomichi

2013-01-01

Vessel wall imaging using radial scanning does not use a blood flow suppression pulse with gated acquisition. It has been proposed that there may not be a flow void effect if the flow rate is slow; however, this has yet to be empirically tested. To clarify the relationship between the signal intensity of the vessel lumen and the blood flow rate in a flow phantom, we investigated the usefulness of vessel wall imaging at 3.0 tesla (T). We measured the signal intensity while changing the flow rate in the flow phantom. Radial scanning at 1.5 T showed sufficient flow voids at above medium flow rates. There was no significant difference in lumen signal intensity at the carotid artery flow rate. The signal intensity of the vessel lumen decreased sufficiently using the radial scan method at 3.0 T. We thus obtained sufficient flow void effects at the carotid artery flow rate. We conclude this technique to be useful for evaluating plaque if high contrast can be maintained for fixed tissue (such as plaque) and the vessel lumen. (author)

Linear-regression convolutional neural network for fully automated coronary lumen segmentation in intravascular optical coherence tomography.

Science.gov (United States)

Yong, Yan Ling; Tan, Li Kuo; McLaughlin, Robert A; Chee, Kok Han; Liew, Yih Miin

2017-12-01

Intravascular optical coherence tomography (OCT) is an optical imaging modality commonly used in the assessment of coronary artery diseases during percutaneous coronary intervention. Manual segmentation to assess luminal stenosis from OCT pullback scans is challenging and time consuming. We propose a linear-regression convolutional neural network to automatically perform vessel lumen segmentation, parameterized in terms of radial distances from the catheter centroid in polar space. Benchmarked against gold-standard manual segmentation, our proposed algorithm achieves average locational accuracy of the vessel wall of 22 microns, and 0.985 and 0.970 in Dice coefficient and Jaccard similarity index, respectively. The average absolute error of luminal area estimation is 1.38%. The processing rate is 40.6 ms per image, suggesting the potential to be incorporated into a clinical workflow and to provide quantitative assessment of vessel lumen in an intraoperative time frame. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Technical Note: Measurement of common carotid artery lumen dynamics using black-blood MR cine imaging.

Science.gov (United States)

Dai, Erpeng; Dong, Li; Zhang, Zhe; Li, Lyu; Zhang, Hui; Zhao, Xihai; Wang, Jinnan; Yuan, Chun; Guo, Hua

2017-03-01

To demonstrate the feasibility of measuring the common carotid artery (CCA) lumen dynamics using a black-blood cine (BB-cine) imaging method. Motion-sensitized driven-equilibrium (MSDE) prepared spoiled gradient sequence was used for the BB-cine imaging. CCAs of eleven healthy volunteers were studied using this method. Lumen dynamics, including lumen area evolution waveforms and distension values, were measured and evaluated by comparing this method with bright-blood cine (BrB-cine) imaging. Compared with the BrB-cine images, flow artifacts were effectively suppressed in the BB-cine images. BrB-cine images generally show larger lumen areas than BB-cine images. The lumen area waveforms and distension measurements from BB-cine imaging showed smaller variances among different subjects than BrB-cine imaging. The proposed BB-cine imaging technique can suppress the flow artifacts effectively and reduce the partial volume effects from the vessel wall. This might allow more accurate lumen dynamics measurements than traditional BrB-cine imaging, which may further be valuable for investigating biomechanical and functional properties of the cardiovascular system. © 2017 American Association of Physicists in Medicine.

Effects of irradiation on renal vessels of rabbits

International Nuclear Information System (INIS)

Hanayama, Hirotaka

1982-01-01

The male rabbits weighing approximately 3 kg were divided into two groups: one group received irradiation to the left kidney through 6 x 4 cm field size with doses of 5 Gy, while the other group was irradiated with 50 Gy. The vessel casts were observed using the injection replica scanning electron microscopic method. In 50 Gy irradiated group, the surface of blood vessel's lumen became irregular with a decrease in the number of glomeruli at 5 days. Partial narrowing was also seen in the cortex and glomerular vessels. The number of glomeruli decreased by 48% one week later and 90% 4 weeks later. The cortex vessels progressively narrowed, and irregularity of the net-like structure was also observed. Similarly, a decrease in the number of glomeruli and partial narrowing of the blood vessels were seen at 5 days on the nonirradiated side, but the damage was considerably less than that on the irradiated side. In the 5 Gy irradiated group, a decrease in the number of glomeruli was seen 5 days later and it became 71% 5 days later and 81% one week later. It returned to 95% 4 weeks later. No changes whatsoever were seen in the non-irradiated side after 4 weeks and changes in the number of glomeruli were not observed. The vasculation of medulla showed no changes in the 50 Gy or the 5 Gy irradiated group. There were seen no significant changes in the blood vessel diameter. (J.P.N.)

A study of magnification effect to precision of computerized diameter measurement of a 3-mm vessel phantom in cineangiograms

International Nuclear Information System (INIS)

Yanagihara, Yoshio; Sugahara, Tetsuo; Sugimoto, Naozou; Fukunishi, Yasunobu.

1994-01-01

To estimate influence of magnification on digitizing to Precision of computerized measurement of coronary vessel diameter, the two measurement methods, i.e., a combined filter and Entropy filter, were applied to magnified images (x1-x6) of cineangiograms radiographed for a 3-mm vessel phantom. In conclusion, the desirable precision in clinical use, we thought, was obtainable at the magnification of x3 to x4. (author)

Regional blood flow analysis and its relationship with arterial branch lengths and lumen volume in the coronary arterial tree

International Nuclear Information System (INIS)

Molloi, Sabee; Wong, Jerry T

2007-01-01

The limitations of visually assessing coronary artery disease are well known. These limitations are particularly important in intermediate coronary lesions (30-70% diameter stenosis) where it is difficult to determine whether a particular lesion is the cause of ischaemia. Therefore, a functional measure of stenosis severity is needed. The purpose of this study is to determine whether the expected maximum coronary blood flow in an arterial tree is predictable from its sum of arterial branch lengths or lumen volume. Using a computer model of a porcine coronary artery tree, an analysis of blood flow distribution was conducted through a network of millions of vessels that included the entire coronary artery tree down to the first capillary branch. The flow simulation results show that there is a linear relationship between coronary blood flow and the sum of its arterial branch lengths. This relationship holds over the entire arterial tree. The flow simulation results also indicate that there is a 3/4 er relation between coronary blood flow (Q) and the sum of its arterial lumen volume (V). Moreover, there is a linear relationship between normalized Q and normalized V raised to a power of 3/4 over the entire arterial tree. These results indicate that measured arterial branch lengths or lumen volumes can be used to predict the expected maximum blood flow in an arterial tree. This theoretical maximum blood flow, in conjunction with an angiographically measured blood flow, can potentially be used to calculate fractional flow reserve based entirely on angiographic data

Diffusive oxygen shunting between vessels in the preglomerular renal vasculature: anatomic observations and computational modeling.

Science.gov (United States)

Gardiner, Bruce S; Thompson, Sarah L; Ngo, Jennifer P; Smith, David W; Abdelkader, Amany; Broughton, Brad R S; Bertram, John F; Evans, Roger G

2012-09-01

To understand how geometric factors affect arterial-to-venous (AV) oxygen shunting, a mathematical model of diffusive oxygen transport in the renal cortex was developed. Preglomerular vascular geometry was investigated using light microscopy (providing vein shape, AV separation, and capillary density near arteries) and published micro-computed tomography (CT) data (providing vessel size and AV separation; Nordsletten DA, Blackett S, Bentley MD, Ritman EL, Smith NP. IUPS Physiome Project. http://www.physiome.org.nz/publications/nordsletten_blackett_ritman_bentley_smith_2005/folder_contents). A "U-shaped" relationship was observed between the arterial radius and the distance between the arterial and venous lumens. Veins were found to partially wrap around the artery more consistently for larger rather than smaller arteries. Intrarenal arteries were surrounded by an area of fibrous tissue, lacking capillaries, the thickness of which increased from ∼5 μm for the smallest arteries (200-μm diameter). Capillary density was greater near smaller arteries than larger arteries. No capillaries were observed between wrapped AV vessel pairs. The computational model comprised a single AV pair in cross section. Geometric parameters critical in renal oxygen transport were altered according to variations observed by CT and light microscopy. Lumen separation and wrapping of the vein around the artery were found to be the critical geometric factors determining the amount of oxygen shunted between AV pairs. AV oxygen shunting increases both as lumen separation decreases and as the degree of wrapping increases. The model also predicts that capillaries not only deliver oxygen, but can also remove oxygen from the cortical parenchyma close to an AV pair. Thus the presence of oxygen sinks (capillaries or tubules) near arteries would reduce the effectiveness of AV oxygen shunting. Collectively, these data suggest that AV oxygen shunting would be favored in larger vessels common to the

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

Retinal hemodynamic oxygen reactivity assessed by perfusion velocity, blood oximetry and vessel diameter measurements

DEFF Research Database (Denmark)

Klefter, Oliver Niels; Lauritsen, Anne Øberg; Larsen, Michael

2015-01-01

PURPOSE: To test the oxygen reactivity of a fundus photographic method of measuring macular perfusion velocity and to integrate macular perfusion velocities with measurements of retinal vessel diameters and blood oxygen saturation. METHODS: Sixteen eyes in 16 healthy volunteers were studied at two...... is a valid method for assessing macular perfusion. Results were consistent with previous observations of hyperoxic blood flow reduction using blue field entoptic and laser Doppler velocimetry. Retinal perfusion seemed to be regulated around individual set points according to blood glucose levels. Multimodal...

Quantification of common carotid artery and descending aorta vessel wall thickness from MR vessel wall imaging using a fully automated processing pipeline.

Science.gov (United States)

Gao, Shan; van 't Klooster, Ronald; Brandts, Anne; Roes, Stijntje D; Alizadeh Dehnavi, Reza; de Roos, Albert; Westenberg, Jos J M; van der Geest, Rob J

2017-01-01

To develop and evaluate a method that can fully automatically identify the vessel wall boundaries and quantify the wall thickness for both common carotid artery (CCA) and descending aorta (DAO) from axial magnetic resonance (MR) images. 3T MRI data acquired with T 1 -weighted gradient-echo black-blood imaging sequence from carotid (39 subjects) and aorta (39 subjects) were used to develop and test the algorithm. The vessel wall segmentation was achieved by respectively fitting a 3D cylindrical B-spline surface to the boundaries of lumen and outer wall. The tube-fitting was based on the edge detection performed on the signal intensity (SI) profile along the surface normal. To achieve a fully automated process, Hough Transform (HT) was developed to estimate the lumen centerline and radii for the target vessel. Using the outputs of HT, a tube model for lumen segmentation was initialized and deformed to fit the image data. Finally, lumen segmentation was dilated to initiate the adaptation procedure of outer wall tube. The algorithm was validated by determining: 1) its performance against manual tracing; 2) its interscan reproducibility in quantifying vessel wall thickness (VWT); 3) its capability of detecting VWT difference in hypertensive patients compared with healthy controls. Statistical analysis including Bland-Altman analysis, t-test, and sample size calculation were performed for the purpose of algorithm evaluation. The mean distance between the manual and automatically detected lumen/outer wall contours was 0.00 ± 0.23/0.09 ± 0.21 mm for CCA and 0.12 ± 0.24/0.14 ± 0.35 mm for DAO. No significant difference was observed between the interscan VWT assessment using automated segmentation for both CCA (P = 0.19) and DAO (P = 0.94). Both manual and automated segmentation detected significantly higher carotid (P = 0.016 and P = 0.005) and aortic (P < 0.001 and P = 0.021) wall thickness in the hypertensive patients. A reliable and reproducible pipeline for fully

Physics of lumen growth.

Science.gov (United States)

Dasgupta, Sabyasachi; Gupta, Kapish; Zhang, Yue; Viasnoff, Virgile; Prost, Jacques

2018-05-22

We model the dynamics of formation of intercellular secretory lumens. Using conservation laws, we quantitatively study the balance between paracellular leaks and the build-up of osmotic pressure in the lumen. Our model predicts a critical pumping threshold to expand stable lumens. Consistently with experimental observations in bile canaliculi, the model also describes a transition between a monotonous and oscillatory regime during luminogenesis as a function of ion and water transport parameters. We finally discuss the possible importance of regulation of paracellular leaks in intercellular tubulogenesis.

[Hemodynamic phenomena in retrobulhar and eyeball vessels].

Science.gov (United States)

Modrzejewska, Monika

2011-01-01

The purpose of this review was to evaluate factors connected with blood flow and indices regulating vascular diameter and some parameters influencing retrobulbar circulation such as type of vascular resistance, anatomical structure of vascular wall and vessel lumen. Neurogenic and angiogenic factors, rheological blood composition, presence of anatomical and pathological obstructions on blood flow pathway as well as degree of development of collateral circulation pathways--have influence on the volume and blood flow velocity in eyeball. There were discussed bulbar circulation hemodynamics, emphasizing the importance of perfusion pressure. The role of risk factors was underlined for pathological lesions in vessels supplying blood to eyeball and in ophthalmic artery (OA) and its collaterals, in central retinal artery (CRA) as well as posterior ciliary arteries (PCAs), and in venous system carrying away blood from eye. IN CONCLUSION--the results of many studies of retrobulbar blood flow in different types of ophthalmic diseases of the vascular etiopathogenesis indicate that registry of the mean values of blood flow parameters and vascular resistance indices parallel to measurement of blood flow spectrum in OA, CRA, PCAs arteries, might contribute much information to explain or to evaluate nature of pathological changes in retinal and choroidal circulation.

The relationship of flow velocities to vessel diameters differs between extracranial carotid and vertebral arteries of stroke patients.

Science.gov (United States)

Owolabi, Mayowa O; Agunloye, Atinuke M; Ogunniyi, Adesola

2014-01-01

Chronic changes in flow rate through arteries produce adjustment of arterial diameters. We compared the relationship between flow velocity and diameter in the carotid and in the vertebral arteries of stroke patients. Using triplex ultrasonography, the internal diameter and flow velocities of the common carotid, internal carotid, and vertebral arteries of 176 consecutive stroke patients were measured. Correlations were examined with Pearson's statistics at an alpha level of 0.05. Mean age of the patients was 59.3 ± 12 years, and 66% had cerebral infarcts. Diameter and blood flow velocities showed significant negative correlations (-0.115 ≥ r ≥ -0.382) in the carotid arteries on both sides, but positive correlations (0.211 ≤ r ≤ 0.320) in the vertebral arteries, even after controlling for age, gender, and blood pressure. Our study demonstrated different diameter/flow relationships in the carotid and the vertebral arteries of stroke patients, which may suggest pathologic changes in the adaptive processes governing vessel diameter and growth, especially in the carotid arteries. Copyright © 2013 Wiley Periodicals, Inc.

Quantification of arterial plaque and lumen density with MDCT

International Nuclear Information System (INIS)

Paul, Narinder S.; Blobel, Joerg; Kashani, Hany; Rice, Murray; Ursani, Ali

2010-01-01

Purpose: This study aimed to derive a mathematical correction function in order to normalize the CT number measurements for small volume arterial plaque and small vessel mimicking objects, imaged with multidetector CT (MDCT). Methods: A commercially available calcium plaque phantom (QRM GmbH, Moehrendorf, Germany) and a custom built cardiovascular phantom were scanned with 320 and 64 MDCT scanners. The calcium hydroxyapatite plaque phantom contained objects 0.5-5.0 mm in diameter with known CT attenuation nominal values ranging 50-800 HU. The cardiovascular phantom contained vessel mimicking objects 1.0-5.0 mm in diameter with different contrast media. Both phantoms were scanned using clinical protocols for CT angiography and images were reconstructed with different filter kernels. The measured CT number (HU) and diameter of each object were analyzed on three clinical postprocessing workstations. From the resultant data, a mathematical formula was derived based on absorption function exp(-μ * d) to demonstrate the relation between measured CT numbers and object diameters. Results: The percentage reduction in measured CT number (HU) for the group of selected filter kernels, apparent during CT angiography, is dependent only on the object size (plaque or vessel diameter). The derived formula of the form 1-c * exp(-a * d b ) showed reduction in CT number for objects between 0.5 and 5 mm in diameter, with asymptote reaching background noise for small objects with diameters nearing the CT in-plane resolution (0.35 mm). No reduction was observed for the objects with diameters equal or larger than 5 mm. Conclusions: A clear mathematical relationship exists between object diameter and reduction in measured CT number in HU. This function is independent of exposure parameters and inherent attenuation properties of the objects studied. Future developments include the incorporation of this mathematical model function into quantification software in order to automatically

Retinal vessel diameters in relation to hematocrit variation during acclimatization of highlanders to sea level altitude

DEFF Research Database (Denmark)

Kofoed, Peter Kristian; Sander, Birgit; Zubieta-Calleja, Gustavo

2009-01-01

PURPOSE: To examine variations in retinal vessel diameters during acclimatization of native highlanders to normobaric normoxia at sea level. METHODS: Fifteen healthy residents of the greater La Paz region in Bolivia (3600 m above sea level) were examined thrice over a 72-day period, after having...... traveled by airplane to Copenhagen, Denmark, near sea level. RESULTS: In the study subjects, hematocrit decreased from 49.6% (day 2) to 45.9% (P = 0.0066, day 23) and 41.7% (P ... diameters were indistinguishable from baseline after 72 days. No funduscopic signs of retinopathy were observed. Arterial blood pressure remained stable throughout the study. CONCLUSIONS: Although a 16% reduction in hematocrit occurred between days 2 and 72 after arrival at sea level, the only significant...

Automated detection and classification of major retinal vessels for determination of diameter ratio of arteries and veins

Science.gov (United States)

Muramatsu, Chisako; Hatanaka, Yuji; Iwase, Tatsuhiko; Hara, Takeshi; Fujita, Hiroshi

2010-03-01

Abnormalities of retinal vasculatures can indicate health conditions in the body, such as the high blood pressure and diabetes. Providing automatically determined width ratio of arteries and veins (A/V ratio) on retinal fundus images may help physicians in the diagnosis of hypertensive retinopathy, which may cause blindness. The purpose of this study was to detect major retinal vessels and classify them into arteries and veins for the determination of A/V ratio. Images used in this study were obtained from DRIVE database, which consists of 20 cases each for training and testing vessel detection algorithms. Starting with the reference standard of vasculature segmentation provided in the database, major arteries and veins each in the upper and lower temporal regions were manually selected for establishing the gold standard. We applied the black top-hat transformation and double-ring filter to detect retinal blood vessels. From the extracted vessels, large vessels extending from the optic disc to temporal regions were selected as target vessels for calculation of A/V ratio. Image features were extracted from the vessel segments from quarter-disc to one disc diameter from the edge of optic discs. The target segments in the training cases were classified into arteries and veins by using the linear discriminant analysis, and the selected parameters were applied to those in the test cases. Out of 40 pairs, 30 pairs (75%) of arteries and veins in the 20 test cases were correctly classified. The result can be used for the automated calculation of A/V ratio.

Porous hybrid structures based on P(DLLA-co-TMC) and collagen for tissue engineering of small-diameter blood vessels

NARCIS (Netherlands)

Buttafoco, L.; Boks, Niels P.; Engbers-Buijtenhuijs, P.; Grijpma, Dirk W.; Poot, Andreas A.; Dijkstra, Pieter J.; Vermes, I.; Feijen, Jan

2006-01-01

Poly (D,L-lactide)-7co-(1,3-trimethylene carbonate) [P(DLLA-co-TMC)] (83 mol % DLLA) was used to produce matrices suitable for tissue engineering of small-diameter blood vessels. The copolymer was processed into tubular structures with a porosity of 98% by melt spinning and fiber winding, thus

Relationship of the duke jeopardy score combined with minimal lumen diameter as assessed by computed tomography angiography to the hemodynamic relevance of coronary artery stenosis.

Science.gov (United States)

Yu, Mengmeng; Zhao, Yonghong; Li, Wenbin; Lu, Zhigang; Wei, Meng; Zhou, Wenxiao; Zhang, Jiayin

2018-03-02

To study the diagnostic performance of the ratio between the Duke jeopardy score (DJS) and the minimal lumen diameter (MLD) (DJS/MLD CT ratio) as assessed by coronary computed tomographic angiography (CTA) for differentiating functionally significant from non-significant coronary artery stenoses, with reference to invasive fractional flow reserve (FFR). Patients who underwent both coronary CTA and FFR measurement during invasive coronary angiography (ICA) within 2 weeks were retrospectively included in the study. Invasive FFR measurement was performed in patients with intermediate to severe coronary stenoseis. DJS/MLD CT ratio and anatomical parameters were recorded. Lesions with FFR ≤0.80 were considered to be functionally significant. One hundred and sixty-one patients with 175 lesions were included into the analysis. Diameter stenosis in CT, area stenosis, plaque burden, lesion length (LL), ICA-based stenosis degree, DJS, LL/MLD 4 ratio, DJS/MLA ratio as well as DJS/MLD ratio were all significantly different between hemodynamically significant and non-significant lesions (pvalue for DJS/MLD CT ratio to be 1.96 (area under curve = 0.863, 95 % confidence interval = 0.803-0.910), yielding a high diagnostic accuracy (86.9%, 152/175). In coronary artery stenoses detected by coronary CTA, the DJS/MLD ratio is able to predict hemodynamic relevance. Copyright © 2018 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Scribble is required for normal epithelial cell–cell contacts and lumen morphogenesis in the mammalian lung

Science.gov (United States)

Yates, Laura L.; Schnatwinkel, Carsten; Hazelwood, Lee; Chessum, Lauren; Paudyal, Anju; Hilton, Helen; Romero, M. Rosario; Wilde, Jonathan; Bogani, Debora; Sanderson, Jeremy; Formstone, Caroline; Murdoch, Jennifer N.; Niswander, Lee A.; Greenfield, Andy; Dean, Charlotte H.

2013-01-01

During lung development, proper epithelial cell arrangements are critical for the formation of an arborized network of tubes. Each tube requires a lumen, the diameter of which must be tightly regulated to enable optimal lung function. Lung branching and lumen morphogenesis require close epithelial cell–cell contacts that are maintained as a result of adherens junctions, tight junctions and by intact apical–basal (A/B) polarity. However, the molecular mechanisms that maintain epithelial cohesion and lumen diameter in the mammalian lung are unknown. Here we show that Scribble, a protein implicated in planar cell polarity (PCP) signalling, is necessary for normal lung morphogenesis. Lungs of the Scrib mouse mutant Circletail (Crc) are abnormally shaped with fewer airways, and these airways often lack a visible, ‘open’ lumen. Mechanistically we show that Scrib genetically interacts with the core PCP gene Vangl2 in the developing lung and that the distribution of PCP pathway proteins and Rho mediated cytoskeletal modification is perturbed in ScribCrc/Crc lungs. However A/B polarity, which is disrupted in Drosophila Scrib mutants, is largely unaffected. Notably, we find that Scrib mediates functions not attributed to other PCP proteins in the lung. Specifically, Scrib localises to both adherens and tight junctions of lung epithelia and knockdown of Scrib in lung explants and organotypic cultures leads to reduced cohesion of lung epithelial cells. Live imaging of Scrib knockdown lungs shows that Scrib does not affect bud bifurcation, as previously shown for the PCP protein Celsr1, but is required to maintain epithelial cohesion. To understand the mechanism leading to reduced cell–cell association, we show that Scrib associates with β-catenin in embryonic lung and the sub-cellular distribution of adherens and tight junction proteins is perturbed in mutant lung epithelia. Our data reveal that Scrib is required for normal lung epithelial organisation and lumen

A Novel Device for True Lumen Re-Entry After Subintimal Recanalization of Superficial Femoral Arteries: First-in-Man Experience and Technical Description

International Nuclear Information System (INIS)

Airoldi, Flavio; Faglia, Ezio; Losa, Sergio; Tavano, Davide; Latib, Azeem; Mantero, Manuela; Lanza, Gaetano; Clerici, Giacomo

2011-01-01

Subintimal angioplasty (SAP) is frequently performed for the treatment of critical limb ischemia (CLI) and has been recognized as an effective technique for these patients. Nevertheless, this approach is limited by the lack of controlled re-entry into the true lumen of the target vessel. We describe a novel device for true lumen re-entry after subintimal recanalization of superficial femoral arteries (SFA). We report our experience with six patients treated between April 2009 and January 2010 with a novel system designed to facilitate true lumen re-entry. The device was advanced by ipsilateral antegrade approach through a 6-French sheath. Successful reaccess into the true lumen was obtained in five of six patients without complications. The patient in whom the reaccess to the true lumen was not possible underwent successful bypass surgery. At 30 days follow-up, the SFA was patent in all patients according to echo-Doppler examination. Our preliminary experience indicates that this novel re-entry device increases the success rate of percutaneous revascularization of chronically occluded SFA.

Quantitative coronary CT angiography: absolute lumen sizing rather than %stenosis predicts hemodynamically relevant stenosis

Energy Technology Data Exchange (ETDEWEB)

Plank, Fabian [Innsbruck Medical University, Department of Radiology, Innsbruck (Austria); Innsbruck Medical University, Department of Internal Medicine III - Cardiology, Innsbruck (Austria); Burghard, Philipp; Mayr, Agnes; Klauser, Andrea; Feuchtner, Gudrun [Innsbruck Medical University, Department of Radiology, Innsbruck (Austria); Friedrich, Guy; Dichtl, Wolfgang [Innsbruck Medical University, Department of Internal Medicine III - Cardiology, Innsbruck (Austria); Wolf, Florian [Vienna Medical University, Department of Cardiovascular and Interventional Radiology, Vienna (Austria)

2016-11-15

To identify the most accurate quantitative coronary stenosis parameter by CTA for prediction of functional significant coronary stenosis resulting in coronary revascularization. 160 consecutive patients were prospectively examined with CTA. Proximal coronary stenosis was quantified by minimal lumen area (MLA) and minimal lumen diameter (MLD), %area and %diameter stenosis. Lesion length (LL) was measured. The reference standard was invasive coronary angiography (ICA) (>70 % stenosis, FFR <0.8). 210 coronary segments were included (59 % positive). MLA of ≤1.8 mm{sup 2} was identified as the optimal cut-off (c = 0.97, p < 0.001; 95 % CI 0.94-0.99) (sensitivity 90.9 %, specificity 89.3 %) for prediction of functional-relevant stenosis (for MLA >2.1 mm{sup 2} sensitivity was 100 %). The optimal cut-off for MLD was 1.2 mm (c = 0.92; p < 0.001; 95 % CI 0.88-95) (sensitivity 90.9, specificity 85.2) while %area and %diameter stenosis were less accurate (c = 0.89; 95 % CI 0.84-93, c = 0.87; 95 % CI 0.82-92, respectively, with thresholds at 73 % and 61 % stenosis). Accuracy for LL was c = 0.74 (95 % CI 0.67-81), and for LL/MLA and LL/MLD ratio c = 0.90 and c = 0.84. MLA ≤1.8 mm{sup 2} and MLD ≤1.2 mm are the most accurate cut-offs for prediction of haemodynamically significant stenosis by ICA, with a higher accuracy than relative % stenosis. (orig.)

LumenRECON Guidewire: Pilot Study of a Novel, Nonimaging Technology for Accurate Vessel Sizing and Delivery of Therapy in Femoropopliteal Disease.

Science.gov (United States)

Nair, Pradeep K; Carr, Jeffrey G; Bigelow, Brian; Bhatt, Deepak L; Berwick, Zachary C; Adams, George

2018-01-01

Proper vessel sizing during endovascular interventions is crucial to avoid adverse procedural and clinical outcomes. LumenRECON (LR) is a novel, nonimaging, 0.035-inch wire-based technology that uses the physics-based principle of Ohm's law to provide a simple, real-time luminal size while also providing a platform for therapy delivery. This study evaluated the accuracy, reliability, and safety of the LR system in patients presenting for a femoropopliteal artery intervention. This multicenter, prospective pilot study of 24 patients presenting for peripheral intervention compared LR measurements of femoropopliteal artery size to angiographic visual estimation, duplex ultrasound, quantitative angiography, and intravascular ultrasound. The primary effectiveness and safety end point was comparison against core laboratory adjudicated intravascular ultrasound values and major adverse events, respectively. Additional preclinical studies were also performed in vitro and in vivo in swine to determine the accuracy of the LR guidewire system. No intra- or postprocedure device-related adverse events occurred. A balloon or stent was successfully delivered in 12 patients (50%) over the LR wire. Differences in repeatability between successive LR measurements was 2.5±0.40% ( R 2 =0.96) with no significant bias. Differences in measurements of LR to other modalities were 0.5±1.7%, 5.0±1.8%, -1.5±2.0%, and 6.8±3.4% for intravascular ultrasound core laboratory, quantitative angiography, angiographic, and duplex ultrasound, respectively. This study demonstrates that through a physics-based principle, LR provides a real-time, safe, reproducible, and accurate vessel size of the femoropopliteal artery during intervention and can additionally serve as a conduit for therapy delivery over its wire-based platform. © 2018 American Heart Association, Inc.

Mechanism of lumen gain with a novel rotational aspiration atherectomy system for peripheral arterial disease: examination by intravascular ultrasound.

Science.gov (United States)

Hassan, Ali H M; Ako, Junya; Waseda, Katsuhisa; Honda, Yasuhiro; Zeller, Thomas; Leon, Martin B; Fitzgerald, Peter J

2010-01-01

The purpose of this study was to evaluate the mechanism of luminal gain with a novel atheroablation system (Pathway PV) for the treatment of peripheral artery disease using intravascular ultrasound (IVUS). The atherectomy system is a rotational atherectomy device, which employs expandable rotating blades with ports that allow flushing and aspiration of the plaque material or thrombus. In this first-in-man clinical study, IVUS analysis was available in 6 patients with lower limb ischemia treated with this device. The treatment results were assessed using IVUS at pre and post atherectomy. Lumen beyond burr size (LBB) was defined as lumen gain divided by the estimated burr area determined by the burr-size. IVUS analysis was available in six patients (superficial femoral artery n=3, popliteal artery n=2, posterior tibial artery n=1). Atheroablation achieved a significant increase in lumen area (LA) (preintervention 3.9+/-0.4, postatheroablation 8.0+/-1.7 mm(2), Patherectomy device achieved significant luminal gain by debulking in the absence of vessel stretching. The LA was greater than burr-sized lumen expectancy at cross-sections along the treated segments, suggesting a complimentary role of aspiration in luminal gain in atherosclerotic peripheral artery lesions.

FFTF and CRBRP reactor vessels

International Nuclear Information System (INIS)

Morgan, R.E.

1977-01-01

The Fast Flux Test Facility (FFTF) reactor vessel and the Clinch River Breeder Reactor Plant (CRBRP) reactor vessel each serve to enclose a fast spectrum reactor core, contain the sodium coolant, and provide support and positioning for the closure head and internal structure. Each vessel is located in its reactor cavity and is protected by a guard vessel which would ensure continued decay heat removal capability should a major system leak develop. Although the two plants have significantly different thermal power ratings, 400 megawatts for FFTF and 975 megawatts for CRBRP, the two reactor vessels are comparable in size, the CRBRP vessel being approximately 28% longer than the FFTF vessel. The FFTF vessel diameter was controlled by the space required for the three individual In-Vessel Handling Machines and Instrument Trees. Utilization of the triple rotating plug scheme for CRBRP refueling enables packaging of the larger CRBRP core in a vessel the same diameter as the FFTF vessel

[Telescopic adhesive anastomosis of small blood vessel applied in formation of arteriovenous fistula for hemodialysis].

Science.gov (United States)

Shen, G; Leng, Y; Rong, G

1997-03-01

The formation of an arteriovenous fistual for dialysis by routine interrupted sutures anastomosing the vein and artery is difficult to perform and time-consuming. A new method, telescopic adhesive anastomosis was studied and applied in 10 hemodialysis patients, who were in need of an arteriovenous fistula. The external diameter of the vessels anastomosed was 2.40 +/- 0.20 mm (radial artery) or 2.40 +/- 0.35 mm (cephalic vein). After thorough debridement of the vascular ends, the arterial end was put in the venous lumen. In order to fix the telescopic vessels, two stitches were applied 180 degrees apart from each other and tied. Each stitch was inserted from vein (penetrating the whole wall) to artery (just through the adventitia and partial thickness of the media vasorum). The distance from the stitch to the edge of the vein was 0.5 mm, and that of the artery was approximated to the external diameter of the vessle. The medical adhesive was then applied for sealing the anastomotic adventitia. Ten seconds were given for the solidification of the adhesive. The patients were followed up for 8 months. The patency rate was 100%, and the rate of blood flow was more than 300 ml/min (measured by ultrasonography). It was shown that this method could be managed easily and quickly, and the so-formed fistula would fulfill the need of hemodialysis.

Bronchial lumen is the safer route for an airway exchange catheter in double-lumen tube replacement: preventable complication in airway management for thoracic surgery.

Science.gov (United States)

Wu, Hsiang-Ling; Tai, Ying-Hsuan; Wei, Ling-Fang; Cheng, Hung-Wei; Ho, Chiu-Ming

2017-10-01

There is no current consensus on which lumen an airway exchange catheter (AEC) should be passed through in double-lumen endotracheal tube (DLT) to exchange for a single-lumen endotracheal tube (SLT) after thoracic surgery. We report an unusual case to provide possible solution on this issue. A 71-year-old man with lung adenocarcinoma had an event of a broken exchange catheter used during a DLT replacement with a SLT, after a video-assisted thoracic surgery. The exchange catheter was impinged at the distal tracheal lumen and snapped during manipulation. All three segments of the catheter were retrieved without further airway compromises. Placement of airway tube exchanger into the tracheal lumen of double-lumen tube is a potential contributing factor of the unusual complication. We suggest an exchange catheter be inserted into the bronchial lumen in optimal depth with the adjunct of video laryngoscope, as the safe method for double-lumen tube exchange.

Can forest dieback and tree death be predicted by prior changes in wood anatomy?

Science.gov (United States)

Colangelo, Michele; Julio Camarero, Jesus; De Micco, Veronica; Borghetti, Marco; Gentilesca, Tiziana; Sanchez-Salguero, Raul; Ripullone, Francesco

2017-04-01

Climate warming is expected to amplify drought stress resulting in more intense and widespread dieback episodes and increasing mortality rates. Studies on quantitative wood anatomy and dendrochronology have demonstrated their potential to supply useful information on the causes of tree decline, although this approach is basically observational and retrospective. Moreover, the long-term reconstruction of wood anatomical features, strictly linked to the evolution of xylem anatomy plasticity through time, allow investigating hydraulic adjustments of trees. In this study, we analyzed wood-anatomical variables in two Italian oak forests where recent episodes of dieback and mortality have been reported. We analyzed in coexisting now-dead and living trees the following wood-anatomical variables: annual tree-ring area, earlywood (EW) and latewood (LW) areas, absolute and relative (%) areas occupied by vessels in the EW and LW, EW and LW vessel areas, EW and LW vessel density and vessel diameter classification. We also calculated the hydraulic diameter (Dh) for all vessels measured within each ring by weighting individual conduit diameters to correspond to the average Hagen-Poiseuille lumen theoretical hydraulic conductivity for a vessel size. Wood-anatomical analyses showed that declining and dead trees were more sensitive to drought stress compared to non declining trees, indicating different susceptibility to water shortage between trees. Dead trees did not form earlywood vessels with smaller lumen diameter than surviving trees but tended to form wider latewood vessels with a higher percentage of vessel area. We discuss the results and implications focusing on those proved more sensitive to the phenomena of decline and mortality.

Absorbed dose calculations to blood and blood vessels for internally deposited radionuclides

International Nuclear Information System (INIS)

Akabani, G.; Poston, J.W. Sr.

1992-01-01

At present, absorbed dose calculations for radionuclides in the human circulatory system use relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, Monte Carlo calculations were performed using the code Electron Gamma Shower (EGS4). Absorbed doses were calculated for the blood and the blood vessel wall (lumen) for different blood vessel sizes. The radionuclides chosen for this study were those commonly used in nuclear medicine. No diffusion of the radionuclide into the blood vessel was or cross fire between blood vessels was assumed. Results are useful in assessing the doses to blood and blood vessel walls for different nuclear medicine procedures

Absorbed dose calculations to blood and blood vessels for internally deposited radionuclides

International Nuclear Information System (INIS)

Akabani, G.; Poston, J.W.

1991-05-01

At present, absorbed dose calculations for radionuclides in the human circulatory system used relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, EGS4 Monte Carlo calculations were performed. Absorbed doses were calculated for the blood and the blood vessel wall (lumen) for different blood vessels sizes. The radionuclides chosen for this study were those commonly used in nuclear medicine. No diffusion of the radionuclide into the blood vessel was assumed nor cross fire between vessel was assumed. Results are useful in assessing the dose in blood and blood vessel walls for different nuclear medicine procedures. 6 refs., 6 figs., 5 tabs

Evaluation of flow volume and flow patterns in the patent false lumen of chronic aortic dissections using velocity-encoded cine magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Inoue, Toshihisa; Watanabe, Shigeru; Sakurada, Hideki; Ono, Katsuhiro; Urano, Miharu; Hijikata, Yasuyoshi; Saito, Isao; Masuda, Yoshiaki [Chiba Univ. (Japan). School of Medicine

2000-10-01

In 21 patients with chronic aortic dissections and proven patent false lumens, the flow volume and flow patterns in the patent false lumens was evaluated using velocity-encoded cine magnetic resonance imaging (VENC-MRI) and the relationship between the flow characteristics and aortic enlargement was retrospectively examined. Flow patterns in the false lumen were divided into 3 groups: pattern A with primarily antegrade flow (n=6), pattern R with primarily retrograde flow (n=3), and pattern B with bidirectional flow (n=12). In group A, the rate of flow volume in the false lumen compared to the total flow volume in true and false lumens (%TFV) and the average rate of enlargement of the maximum diameter of the dissected aorta per year ({delta}D) were significantly greater than in groups R and B (%TFV: 74.1{+-}0.07 vs 15.2{+-}0.03 vs 11.8{+-}0.04, p<0.01; {delta}D: 3.62{+-}0.82 vs 0 vs 0.58{+-}0.15 mm/year, p<0.05, respectively). There was a significant correlation between %TFV and {delta}D (r=0.79, p<0.0001). Evaluation of flow volume and flow patterns in the patent false lumen using VENC-MRI may be useful for predicting enlargement of the dissected aorta. (author)

The diagnostic value of cine-MR imaging in diseases of great vessels

International Nuclear Information System (INIS)

Sasaki, Shigeyuki; Yoshida, Hideaki; Matsui, Yoshiro; Sakuma, Makoto; Yasuda, Keihide; Tanabe, Tatsuzo; Chouji, H.

1990-01-01

The diagnostic value of cine magnetic resonance imaging (cine-MRI) was evaluated in 10 patients with diseases of great vessels. The parameters necessary to decide the appropriate treatment, such as presence and extension of intimal flap, DeBakey type classification, identification of the entry, differentiation between true and false lumen, and between thrombosis and slow flow were demonstrated in all patients with dissecting aortic aneurysm. However, abdominal aortic branches could not be demonstrated enough by cine-MRI, therefore conventional AOG was necessary to choose the operative procedure in these cases. In patients with thoracic aortic aneurysm (TAA), cine-MRI was valuable in demonstrating both blood flow and thrombus in the lumen of aneurysm, and AOG was thought to be unnecessary in most cases. Cine-MRI is a promising new technique for the evaluation of diseases of great vessels. (author)

ARCOCT: Automatic detection of lumen border in intravascular OCT images.

Science.gov (United States)

Cheimariotis, Grigorios-Aris; Chatzizisis, Yiannis S; Koutkias, Vassilis G; Toutouzas, Konstantinos; Giannopoulos, Andreas; Riga, Maria; Chouvarda, Ioanna; Antoniadis, Antonios P; Doulaverakis, Charalambos; Tsamboulatidis, Ioannis; Kompatsiaris, Ioannis; Giannoglou, George D; Maglaveras, Nicos

2017-11-01

Intravascular optical coherence tomography (OCT) is an invaluable tool for the detection of pathological features on the arterial wall and the investigation of post-stenting complications. Computational lumen border detection in OCT images is highly advantageous, since it may support rapid morphometric analysis. However, automatic detection is very challenging, since OCT images typically include various artifacts that impact image clarity, including features such as side branches and intraluminal blood presence. This paper presents ARCOCT, a segmentation method for fully-automatic detection of lumen border in OCT images. ARCOCT relies on multiple, consecutive processing steps, accounting for image preparation, contour extraction and refinement. In particular, for contour extraction ARCOCT employs the transformation of OCT images based on physical characteristics such as reflectivity and absorption of the tissue and, for contour refinement, local regression using weighted linear least squares and a 2nd degree polynomial model is employed to achieve artifact and small-branch correction as well as smoothness of the artery mesh. Our major focus was to achieve accurate contour delineation in the various types of OCT images, i.e., even in challenging cases with branches and artifacts. ARCOCT has been assessed in a dataset of 1812 images (308 from stented and 1504 from native segments) obtained from 20 patients. ARCOCT was compared against ground-truth manual segmentation performed by experts on the basis of various geometric features (e.g. area, perimeter, radius, diameter, centroid, etc.) and closed contour matching indicators (the Dice index, the Hausdorff distance and the undirected average distance), using standard statistical analysis methods. The proposed method was proven very efficient and close to the ground-truth, exhibiting non statistically-significant differences for most of the examined metrics. ARCOCT allows accurate and fully-automated lumen border

Dependence of diameters and oxygen saturation of retinal vessels on visual field damage and age in primary open-angle glaucoma.

Science.gov (United States)

Ramm, Lisa; Jentsch, Susanne; Peters, Sven; Sauer, Lydia; Augsten, Regine; Hammer, Martin

2016-05-01

To investigate the interrelationship between the oxygen supply of the retina and its regulation with the severity of primary open-angle glaucoma (POAG). Central retinal artery (CRAE) and vein (CRVE) diameters and oxygen saturation of peripapillary retinal vessels in 41 patients suffering from POAG (64.1 ± 12.9 years) and 40 healthy volunteers (63.6 ± 14.1 years) were measured using the retinal vessel analyzer. All measures were taken before and during flicker light stimulation. The mean retinal nerve fiber layer thickness (RNFLT) was determined by OCT and the visual field mean defect (MD) was identified using perimetry. In glaucoma patients, CRAE (r = -0.48 p = 0.002) and CRVE (r = -0.394 p = 0.014) at baseline were inversely related to MD, while arterial and venous oxygen saturation showed no significant dependence on the severity of the damage. However, the flicker light-induced change in arterio-venous difference in oxygen saturation was correlated with the MD (r = 0.358 p = 0.027). The diameters of arteries and veins at baseline decreased with reduction of the mean RNFLT (arteries: r = 0.718 p field loss, may be explained by a reduction of the retinal metabolic demand with progressive loss of neuronal tissue in glaucoma. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Retinal vessel diameters decrease with macular ganglion cell layer thickness in autosomal dominant optic atrophy and in healthy subjects

DEFF Research Database (Denmark)

Rönnbäck, Cecilia; Grønskov, Karen; Larsen, Michael

2014-01-01

diameters (central retinal artery equivalent, CRAE, and central retinal vein equivalent, CRVE). Statistical analysis was corrected for age, gender, spherical equivalent refraction, axial length and mean arterial blood pressure (MABP) in a mixed model analysis. RESULTS: Retinal arteries and veins were...... ganglion cell-inner plexiform layer (GC-IPL) thickness (p = 0.0017 and p = 0.0057, respectively). CONCLUSION: Narrow retinal arteries and veins were associated not only with the severity of ADOA but with ganglion cell volume in patients with ADOA and in healthy subjects. This suggests that narrow vessels...

Public relations ve firmě LUMEN INTERNATIONAL a.s.

OpenAIRE

DICHTLOVÁ, Hana

2012-01-01

Goal of the thesis was to assess current significance and usage of public relations in LUMEN INTERNATIONAL a.s. company and to create plan of another development. The author analysed development and current situation of public relations in LUMEN holding. There are a few suggestions in this thesis how to improve public relations in whole LUMEN holding.

Dual-Source CT Angiography of Peripheral Arterial Stents: In Vitro Evaluation of 22 Different Stent Types

Directory of Open Access Journals (Sweden)

Michael Köhler

2011-01-01

Full Text Available Purpose. To test different peripheral arterial stents using four image reconstruction approaches with respect to lumen visualization, lumen attenuation and image noise in dual-source multidetector row CT (DSCT in vitro. Methods and Materials. 22 stents (nitinol, steel, cobalt-alloy, tantalum, platinum alloy were examined in a vessel phantom. All stents were imaged in axial orientation with standard parameters. Image reconstructions were obtained with four different convolution kernels. To evaluate visualization characteristics of the stent, the lumen diameter, intraluminal density and noise were measured. Results. The mean percentage of the visible stent lumen diameter from the nominal stent diameter was 74.5% ± 5.7 for the medium-sharp kernel, 72.8% ± 6.4 for the medium, 70.8% ± 6.4 for the medium-smooth and 67.6% ± 6.6 for the smooth kernel. Mean values of lumen attenuation were 299.7HU ± 127 (medium-sharp, 273.9HU ± 68 (medium, 270.7HU ± 53 (medium-smooth and 265.8HU ± 43. Mean image noise was: 54.6 ± 6.3, 20.5 ± 1.7, 16.3 ± 1.7, 14.0 ± 2 respectively. Conclusion. Visible stent lumen diameter varies depending on stent type and scan parameters. Lumen diameter visibility increases with the sharpness of the reconstruction kernel. Smoother kernels provide more realistic density measurements inside the stent lumen and less image noise.

Laser beam diameter for port wine stain treatment

NARCIS (Netherlands)

Keijzer, M.; Pickering, J. W.; van Gemert, M. J.

1991-01-01

Optimal port wine stain treatment requires the selective absorption of light by the ectatic blood vessels. We investigated whether deeper blood vessels can be coagulated, without damaging other cutaneous structures, by varying the laser beam diameter. The penetration of the light was simulated with

Retinal Oximetry and Vessel Diameter Measurements With a Commercially Available Scanning Laser Ophthalmoscope in Diabetic Retinopathy.

Science.gov (United States)

Blair, Norman P; Wanek, Justin; Felder, Anthony E; Joslin, Charlotte E; Kresovich, Jacob K; Lim, Jennifer I; Chau, Felix Y; Leiderman, Yannek; Shahidi, Mahnaz

2017-10-01

To test the hypothesis that retinal vascular diameter and hemoglobin oxygen saturation alterations, according to stages of diabetic retinopathy (DR), are discernible with a commercially available scanning laser ophthalmoscope (SLO). One hundred eighty-one subjects with no diabetes (No DM), diabetes with no DR (No DR), nonproliferative DR (NPDR), or proliferative DR (PDR, all had photocoagulation) underwent imaging with an SLO with dual lasers (532 nm and 633 nm). Customized image analysis software determined the diameters of retinal arteries and veins (DA and DV) and central retinal artery and vein equivalents (CRAE and CRVE). Oxygen saturations of hemoglobin in arteries and veins (SO2A and SO2V) were estimated from optical densities of vessels on images at the two wavelengths. Statistical models were generated by adjusting for effects of sex, race, age, eye, and fundus pigmentation. DA, CRAE, and CRVE were reduced in PDR compared to No DM (P ≤ 0.03). DV and CRVE were similar between No DM and No DR, but they were higher in NPDR than No DR (P ≤ 0.01). Effect of stage of disease on SO2A differed by race, being increased relative to No DM in NPDR and PDR in Hispanic participants only (P ≤ 0.02). Relative to No DM, SO2V was increased in NPDR and PDR (P ≤ 0.05). Alterations in retinal vascular diameters and SO2 by diabetic retinopathy stage can be detected with a widely available SLO, and covariates such as race can influence the results.

Evaluation of flow volume and flow patterns in the patent false lumen of chronic aortic dissections using velocity-encoded cine magnetic resonance imaging

International Nuclear Information System (INIS)

Inoue, Toshihisa; Watanabe, Shigeru; Sakurada, Hideki; Ono, Katsuhiro; Urano, Miharu; Hijikata, Yasuyoshi; Saito, Isao; Masuda, Yoshiaki

2000-01-01

In 21 patients with chronic aortic dissections and proven patent false lumens, the flow volume and flow patterns in the patent false lumens was evaluated using velocity-encoded cine magnetic resonance imaging (VENC-MRI) and the relationship between the flow characteristics and aortic enlargement was retrospectively examined. Flow patterns in the false lumen were divided into 3 groups: pattern A with primarily antegrade flow (n=6), pattern R with primarily retrograde flow (n=3), and pattern B with bidirectional flow (n=12). In group A, the rate of flow volume in the false lumen compared to the total flow volume in true and false lumens (%TFV) and the average rate of enlargement of the maximum diameter of the dissected aorta per year (ΔD) were significantly greater than in groups R and B (%TFV: 74.1±0.07 vs 15.2±0.03 vs 11.8±0.04, p<0.01; ΔD: 3.62±0.82 vs 0 vs 0.58±0.15 mm/year, p<0.05, respectively). There was a significant correlation between %TFV and ΔD (r=0.79, p<0.0001). Evaluation of flow volume and flow patterns in the patent false lumen using VENC-MRI may be useful for predicting enlargement of the dissected aorta. (author)

SU-E-I-25: Quantification of Coronary Artery Cross-Sectional Area in CT Angiography Using Integrated Density: A Simulation Study

International Nuclear Information System (INIS)

Johnson, T; Ding, H; Lipinski, J; Molloi, S

2015-01-01

Purpose: To develop a physics-based model for accurate quantification of the cross-sectional area (CSA) of coronary arteries in CT angiography by measuring the integrated density to account for the partial volume effect. Methods: In this technique the integrated density of the object as compared with its local background is measured to account for the partial volume effect. Normal vessels were simulated as circles with diameters in the range of 0.1–3mm. Diseased vessels were simulated as 2, 3, and 4mm diameter vessels with 10–90% area stenosis, created by inserting circular plaques. A simplified two material model was used with the lumen as 8mg/ml Iodine and background as lipid. The contrast-to-noise ratio between lumen and background was approximately 26. Linear fits to the known CSA were calculated. The precision and accuracy of the measurement were quantified using the root-mean-square fit deviations (RMSD) and errors to the known CSA (RMSE). Results compared to manual segmentation of the vessel lumen. To assess the impact of random variations, coefficients of variation (CV) from 10 simulations for each vessel were computed to determine reliability. Measurements with CVs less than 10% were considered reliable. Results: For normal vessels, the precision and accuracy of the integrated density technique were 0.12mm 2 and 0.28mm 2 , respectively. The corresponding results for manual segmentation were 0.27mm 2 and 0.43mm 2 . For diseased vessels, the precision and accuracy of the integrated density technique were 0.14mm 2 and 0.19mm 2 . Corresponding results for manual segmentation were 0.42mm 2 and 0.71mm 2 . Reliable CSAs were obtained for normal vessels with diameters larger than 1 mm and for diseased vessels with area as low as 1.26mm2. Conclusion: The CSA based on integrated density showed improved precision and accuracy as compared with manual segmentation in simulation. These results indicate the potential of using integrated density to quantify CSA of

About a mechanism of the influence of shear stress for viscosity of the blood in vessels of small diameter

Directory of Open Access Journals (Sweden)

Лев Николаевич Катюхин

2014-12-01

Full Text Available It is proposed a physiological and experimentally confirmed explanation of Fåhraeus-Lindqvist-effect in capillaries using the profile analyses of osmotic deformability of red blood cells. It was shown the dose-dependent change of the erythrocytes deformability in the stage of isotropic spheres after forming artificial water pores (nystatin and occlusion (PbCl2 of available pores. The Sigma-effect reducing of hematocrit and viscosity in a shear flow of blood through the vessels of a small diameter was conditioned by the interchange of liquid phase between the erythrocyte and the plasma.

Polarized protein transport and lumen formation during epithelial tissue morphogenesis.

Science.gov (United States)

Blasky, Alex J; Mangan, Anthony; Prekeris, Rytis

2015-01-01

One of the major challenges in biology is to explain how complex tissues and organs arise from the collective action of individual polarized cells. The best-studied model of this process is the cross talk between individual epithelial cells during their polarization to form the multicellular epithelial lumen during tissue morphogenesis. Multiple mechanisms of apical lumen formation have been proposed. Some epithelial lumens form from preexisting polarized epithelial structures. However, de novo lumen formation from nonpolarized cells has recently emerged as an important driver of epithelial tissue morphogenesis, especially during the formation of small epithelial tubule networks. In this review, we discuss the latest findings regarding the mechanisms and regulation of de novo lumen formation in vitro and in vivo.

Dual energy CT of the peripheral arteries. A phantom study to assess the effect of automatic plaque removal on stenosis grading

Energy Technology Data Exchange (ETDEWEB)

Werncke, T.; Wolf, K.J.; Meyer, B.C. [Charite Universitaetsmedizin Berlin (Germany). Klinik und Hochschulambulanz fuer Radiologie und Nuklearmedizin; Albrecht, T. [Institut fuer Radiologie und Interventionelle Therapie, Vivantes, Neukoelln (Germany)

2010-08-15

Purpose: To evaluate the accuracy of dual energy (DE)-based plaque removal in a vessel phantom. Materials and Methods: Acrylic vessel phantoms of different diameters (3, 5, 8 mm), degrees of stenoses (25 - 100 %) and plaque densities (300 - 750 HU) were filled with contrast-enhanced blood (150 - 450 HU). Dual source CT was used for simultaneous image acquisition at 80 and 140 kV. Beside a DE-based plaque-subtracted dataset (DE-PS), a virtual 120 kV non-plaque subtracted dataset (N-PS) was generated. Agreement between the known and measured luminal diameter in both datasets was determined using Lin's concordance correlation coefficient (KLin). Results: A total of 8260 measurements were taken. The correlation of measured diameter in DE-PS images was excellent (KLin = 0.83 - 0.96) for 5 - 8 mm vessel phantoms with high luminal enhancement (300 - 450 HU) and plaque density (500 - 750 HU), moderate (KLin = 0.6 - 0.67) for 5 mm vessels with lower luminal enhancement and plaque density and poor (KLin = 0.10 - 0.64) in the 3 mm vessels. The correlation of N-PS-based stenosis quantification was excellent (KLin = 0.86 - 0.99) for 5 - 8 mm vessel phantoms if the contrast between lumen and plaque was above 100 HU. The correlation decreased in 3 mm vessels (KLin = 0.45 - 0.93), while the lowest correlation was observed for the lowest contrast between plaque and vessel lumen. Conclusion: Automatic DE-based plaque removal is highly effective for heavily calcified plaques and high luminal enhancement in larger diameter vessels {>=} 5 mm. However, accuracy is limited for low density calcified plaque, lower luminal enhancement and smaller caliber vessels mainly due to poor specificity. (orig.)

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

Science.gov (United States)

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

2017-10-01

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. The proposed method segments the lumen and outer wall surfaces including the bifurcation region by fitting a subdivision surface constructed hierarchical-tree model to the image data. In particular, a hybrid segmentation which combines deformable model fitting with boundary classification was applied to extract the lumen surface. The 3D model ensures the correct shape and topology of the carotid artery, while the boundary classification uses combined image information of 3D TOF-MRA and 3D BB-MRI to promote accurate delineation of the lumen boundaries. The proposed algorithm was validated on 25 subjects (48 arteries) including both healthy volunteers and atherosclerotic patients with 30% to 70% carotid stenosis. For both lumen and outer wall border detection, our result shows good agreement between manually and automatically determined contours, with contour-to-contour distance less than 1 pixel as well as Dice overlap greater than 0.87 at all different carotid artery sections. The presented 3D segmentation technique has demonstrated the capability of providing vessel wall delineation for 3D carotid MRI data with high accuracy and limited user interaction. This brings benefits to large-scale patient studies for assessing the effect of pharmacological treatment of atherosclerosis by reducing image analysis time and bias between human observers. © 2017 American Association of Physicists in Medicine.

Does bipolar electrocoagulation time affect vessel weld strength?

Science.gov (United States)

Harrison, J D; Morris, D L

1991-01-01

The value of the bipolar electrocoagulator in the haemostasis of bleeding ulcers is controversial. We have therefore investigated the effect of different coagulation times on vessel weld strength achieved by the bipolar device. Welds were then made in vessels of known diameter using a standard 10F endoscopic haemostatic probe at coagulation times of two and 20 seconds. The intravascular temperature achieved at each time was measured. Vessel weld strength achieved by bipolar electrocoagulation was much greater at 20 seconds (approximately twice that at two seconds) and was highly significantly greater at all vessel diameters. There was a gradual reduction in weld strength with increasing vessel diameter, an effect that was seen for both two and 20 seconds of electrocoagulation. Intravascular temperature was significantly higher at 20 seconds than at two seconds. We conclude that vessel weld strength is related to coagulation time and that any future studies comparing the bipolar electrocoagulator with other haemostatic devices should use longer periods of bipolar electrocoagulation and record the coagulation time in order to optimise the clinical value of the device. PMID:1864540

Spermine oxidase promotes bile canalicular lumen formation through acrolein production.

Science.gov (United States)

Uemura, Takeshi; Takasaka, Tomokazu; Igarashi, Kazuei; Ikegaya, Hiroshi

2017-11-01

Spermine oxidase (SMOX) catalyzes oxidation of spermine to generate spermidine, hydrogen peroxide (H 2 O 2 ) and 3-aminopropanal, which is spontaneously converted to acrolein. SMOX is induced by a variety of stimuli including bacterial infection, polyamine analogues and acetaldehyde exposure. However, the physiological functions of SMOX are not yet fully understood. We investigated the physiological role of SMOX in liver cells using human hepatocellular carcinoma cell line HepG2. SMOX localized to the bile canalicular lumen, as determined by F-actin staining. Knockdown of SMOX reduced the formation of bile canalicular lumen. We also found that phospho-Akt (phosphorylated protein kinase B) was localized to canalicular lumen. Treatment with Akt inhibitor significantly reduced the formation of bile canalicular lumen. Acrolein scavenger also inhibited the formation of bile canalicular lumen. PTEN, phosphatase and tensin homolog and an inhibitor of Akt, was alkylated in a SMOX-dependent manner. Our results suggest that SMOX plays a central role in the formation of bile canalicular lumen in liver cells by activating Akt pathway through acrolein production.

The Precise Determination of Vascular Lumen and Stent Diameters: Correlation Among Calibrated Angiography, Intravascular Ultrasound, and Pressure-Fixed Specimens

International Nuclear Information System (INIS)

Froelich, Jens J.; Hoppe, Martin; Nahrstedt, Christoph; Barth, Klemens H.; Wagner, H. Joachim; Klose, Klaus J.

1997-01-01

Purpose: Luminal diameters measured in vivo by calibrated-catheter angiography and by intravascular ultrasound were correlated with those obtained from pressure-fixed histologic cross-sections to determine the accuracy of both methods. Methods: Angiographic and endosonographic diameter measurements were performed in the center of stents placed in the iliac arteries of 10 miniature pigs and were compared with luminal and stent diameters in postmortem, pressure-fixed, histologic cross-sections from identical locations. Results: Compared with histologic diameters, magnification-corrected angiographic measurements still magnified vascular luminal diameters by 0.7 ± 0.71 mm (r= 0.41, Pearson; p 0.5, Wilcoxon, matched pairs). Similarly, stent diameters correlated well between endosonographic and histologic measurements (r= 0.91; p= 0.002), and less well between angiographic and histologic diameters (r= 0.62; p= 0.002). Conclusion: Since calibrated angiography still overestimates vascular lumina, endosonography is the preferred technique for accurate in vivo measurements

Defining an adequate sample of earlywood vessels for retrospective injury detection in diffuse-porous species.

Directory of Open Access Journals (Sweden)

Estelle Arbellay

Full Text Available Vessels of broad-leaved trees have been analyzed to study how trees deal with various environmental factors. Cambial injury, in particular, has been reported to induce the formation of narrower conduits. Yet, little or no effort has been devoted to the elaboration of vessel sampling strategies for retrospective injury detection based on vessel lumen size reduction. To fill this methodological gap, four wounded individuals each of grey alder (Alnus incana (L. Moench and downy birch (Betula pubescens Ehrh. were harvested in an avalanche path. Earlywood vessel lumina were measured and compared for each tree between the injury ring built during the growing season following wounding and the control ring laid down the previous year. Measurements were performed along a 10 mm wide radial strip, located directly next to the injury. Specifically, this study aimed at (i investigating the intra-annual duration and local extension of vessel narrowing close to the wound margin and (ii identifying an adequate sample of earlywood vessels (number and intra-ring location of cells attesting to cambial injury. Based on the results of this study, we recommend analyzing at least 30 vessels in each ring. Within the 10 mm wide segment of the injury ring, wound-induced reduction in vessel lumen size did not fade with increasing radial and tangential distances, but we nevertheless advise favoring early earlywood vessels located closest to the injury. These findings, derived from two species widespread across subarctic, mountainous, and temperate regions, will assist retrospective injury detection in Alnus, Betula, and other diffuse-porous species as well as future related research on hydraulic implications after wounding.

Is quantitative coronary angiography reliable in assessing the late lumen loss of the everolimus-eluting bioresorbable polylactide scaffold in comparison with the cobalt-chromium metallic stent?

NARCIS (Netherlands)

Sotomi, Yohei; Onuma, Yoshinobu; Miyazaki, Yosuke; Asano, Taku; Katagiri, Yuki; Tenekecioglu, Erhan; Jonker, Hans; Dijkstra, Jouke; de Winter, Robbert J.; Wykrzykowska, Joanna J.; Stone, Gregg W.; Popma, Jeffrey J.; Kozuma, Ken; Tanabe, Kengo; Serruys, Patrick W.; Kimura, Takeshi

2017-01-01

Aims: Immediately after stent/scaffold implantation, quantitative coronary angiography (QCA) in comparison to optical coherence tomography (OCT) more severely underestimates the lumen diameter (LD) in Absorb than in XIENCE. This OCT-QCA discrepancy has not been evaluated at long-term follow-up. The

High-performance fiber/epoxy composite pressure vessels

Science.gov (United States)

Chiao, T. T.; Hamstad, M. A.; Jessop, E. S.; Toland, R. H.

1978-01-01

Activities described include: (1) determining the applicability of an ultrahigh-strength graphite fiber to composite pressure vessels; (2) defining the fatigue performance of thin-titanium-lined, high-strength graphite/epoxy pressure vessel; (3) selecting epoxy resin systems suitable for filament winding; (4) studying the fatigue life potential of Kevlar 49/epoxy pressure vessels; and (5) developing polymer liners for composite pressure vessels. Kevlar 49/epoxy and graphite fiber/epoxy pressure vessels, 10.2 cm in diameter, some with aluminum liners and some with alternation layers of rubber and polymer were fabricated. To determine liner performance, vessels were subjected to gas permeation tests, fatigue cycling, and burst tests, measuring composite performance, fatigue life, and leak rates. Both the metal and the rubber/polymer liner performed well. Proportionately larger pressure vessels (20.3 and 38 cm in diameter) were made and subjected to the same tests. In these larger vessels, line leakage problems with both liners developed the causes of the leaks were identified and some solutions to such liner problems are recommended.

Targeting Therapy Resistant Tumor Vessels

Science.gov (United States)

2008-08-01

Morris LS. Hysterectomy vs. resectoscopic endometrial ablation for the control of abnormal uterine bleeding . A cost-comparative study. J Reprod Med 1994;39...after the antibody treatment contain a pericyte coat, vessel architecture is normal, the diameter of the vessels is smaller (dilated, abnormal vessels...involvement of proteases from inflammatory mast cells and functionally abnormal (Carmeliet and Jain, 2000; Pasqualini (Coussens et al., 1999) and other bone

Sensitivity and related factors in iodine-123-β-methyl-p-iodophenyl-pentadecanoic acid myocardial scintigraphy to detect stable effort angina pectoris

International Nuclear Information System (INIS)

Tanaka, Tetsuya; Ohtsuki, Yumi; Takechi, Norikazu; Suzuki, Kenji; Nishibori, Yoshiharu; Matsuo, Akiko; Inoue, Keiji; Fujita, Hiroshi; Inoue, Naoto

2005-01-01

This study evaluated the sensitivity and the related factors in iodine-123-β-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) scintigraphy to detect stable angina. The subjects were 198 patients with stable angina who underwent BMIPP before percutaneous coronary intervention or coronary bypass graft surgery. Patients with unstable angina, myocardial infarction, congestive heart failure, cardiomyopathy and vasospastic angina were excluded. After investigation of the sensitivity of BMIPP, the patients with single-vessel disease without collateral flow were classified into the normal 12 3 I-BMIPP uptake group (normal group) or decreased 123 I-BMIPP uptake group (decreased group), and various factors were compared between the two groups. Sensitivity was 61% overall, 58% in single-vessel disease, 69% in double-vessel disease, 53% in triple-vessel disease, 43% in only left main vessel disease, and 89% in left main and other vessel disease (NS). In single-vessel disease, the sensitivity was 40% in 75% coronary artery stenosis, 58% in 90% stenosis, 89% in 99% stenosis, and 69% in total occlusion (p=0.003). Comparing the decreased and normal groups, diabetes mellitus was more frequent in the normal group (14.6% vs 39.5%), minimal lumen diameter was smaller (0.75±0.37 vs 0.98±0.49 mm) and lesion length was longer in the decreased group (15.4±4.9 vs 11.6±5.5 mm). Logistic multivariate analysis showed that the independent factors were diabetes mellitus [odds ratio 0.20, 95% confidence interval (CI) 0.04-0.87, p=0.03], minimal lumen diameter (odds ratio 0.10, 95% CI 0.02-0.48, p=0.003) and lesion length (odds ratio 1.12, 95% CI 1.00-1.25, p=0.03). BMIPP is useful in stable angina patients because of the acceptable sensitivity. Diabetes mellitus, minimal lumen diameter and lesion length were independent factors associated with decreased BMIPP uptake. (author)

Accuracy of geometrical modelling of heat transfer from tissue to blood vessels

NARCIS (Netherlands)

Leeuwen, van G.M.J.; Kotte, A.N.T.J.; Bree, de J.; Koijk, van der J.F.; Crezee, J.; Lagendijk, J.J.W.

1997-01-01

We have developed a thermal model in which blood vessels are described as geometrical objects, 3D curves with associated diameters. Here the behaviour of the model is examined for low resolutions compared with the vessel diameter and for strongly curved vessels. The tests include a single straight

Subadventitial techniques for chronic total occlusion percutaneous coronary intervention: The concept of "vessel architecture".

Science.gov (United States)

Azzalini, Lorenzo; Carlino, Mauro; Brilakis, Emmanouil S; Vo, Minh; Rinfret, Stéphane; Uretsky, Barry F; Karmpaliotis, Dimitri; Colombo, Antonio

2018-03-01

Despite improvements in guidewire technologies, the traditional antegrade wire escalation approach to chronic total occlusion (CTO) recanalization is successful in only 60-80% of selected cases. In particular, long, calcified, and tortuous occlusions are less successfully approached with a true-to-true lumen approach. Frequently, the guidewire tracks into the subadventitial space, with no guarantee of distal re-entry into the true lumen. The ability to manage the subadventitial space has been a key step in the tremendous improvement in success rates of contemporary CTO percutaneous coronary intervention (PCI), whether operating antegradely or retrogradely. A modern approach to CTO PCI involves understanding the concept of "vessel architecture," which is based on the distinction between coronary structures (occlusive plaque, comprising the disrupted intima and media, and the outer adventitia) and extravascular space. The vessel architecture represents a safe work environment for guidewire and device manipulation. This review provides an anatomy-based description of the concept of vessel architecture, along with a historical perspective of subadventitial techniques for CTO PCI, and outcome data of CTO PCI utilizing the subadventitial space. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Vessel size measurements in angiograms: A comparison of techniques

International Nuclear Information System (INIS)

Hoffmann, Kenneth R.; Nazareth, Daryl P.; Miskolczi, Laszlo; Gopal, Anant; Wang Zhou; Rudin, Stephen; Bednarek, Daniel R.

2002-01-01

As interventional procedures become more complicated, the need for accurate quantitative vascular information increases. In response to this need, many commercial vendors provide techniques for measurement of vessel sizes, usually based on derivative techniques. In this study, we investigate the accuracy of several techniques used in the measurement of vessel size. Simulated images of vessels having circular cross sections were generated and convolved with various focal spot distributions taking into account the magnification. These vessel images were then convolved with Gaussian image detector line spread functions (LSFs). Additionally, images of a phantom containing vessels with a range of diameters were acquired for the 4.5'', 6'', 9'', and 12'' modes of an image intensifier-TV (II-TV) system. Vessel sizes in the images were determined using a first-derivative technique, a second-derivative technique, a linear combination of these two measured sizes, a thresholding technique, a densitometric technique, and a model-based technique. For the same focal spot size, the shape of the focal spot distribution does not affect measured vessel sizes except at large magnifications. For vessels with diameters larger than the full-width-at-half-maximum (FWHM) of the LSF, accurate vessel sizes (errors ∼0.1 mm) could be obtained by using an average of sizes determined by the first and second derivatives. For vessels with diameters smaller than the FWHM of the LSF, the densitometric and model-based techniques can provide accurate vessel sizes when these techniques are properly calibrated

Automatic segmentation and 3D reconstruction of intravascular ultrasound images for a fast preliminar evaluation of vessel pathologies.

Science.gov (United States)

Sanz-Requena, Roberto; Moratal, David; García-Sánchez, Diego Ramón; Bodí, Vicente; Rieta, José Joaquín; Sanchis, Juan Manuel

2007-03-01

Intravascular ultrasound (IVUS) imaging is used along with X-ray coronary angiography to detect vessel pathologies. Manual analysis of IVUS images is slow and time-consuming and it is not feasible for clinical purposes. A semi-automated method is proposed to generate 3D reconstructions from IVUS video sequences, so that a fast diagnose can be easily done, quantifying plaque length and severity as well as plaque volume of the vessels under study. The methodology described in this work has four steps: a pre-processing of IVUS images, a segmentation of media-adventitia contour, a detection of intima and plaque and a 3D reconstruction of the vessel. Preprocessing is intended to remove noise from the images without blurring the edges. Segmentation of media-adventitia contour is achieved using active contours (snakes). In particular, we use the gradient vector flow (GVF) as external force for the snakes. The detection of lumen border is obtained taking into account gray-level information of the inner part of the previously detected contours. A knowledge-based approach is used to determine which level of gray corresponds statistically to the different regions of interest: intima, plaque and lumen. The catheter region is automatically discarded. An estimate of plaque type is also given. Finally, 3D reconstruction of all detected regions is made. The suitability of this methodology has been verified for the analysis and visualization of plaque length, stenosis severity, automatic detection of the most problematic regions, calculus of plaque volumes and a preliminary estimation of plaque type obtaining for automatic measures of lumen and vessel area an average error smaller than 1mm(2) (equivalent aproximately to 10% of the average measure), for calculus of plaque and lumen volume errors smaller than 0.5mm(3) (equivalent approximately to 20% of the average measure) and for plaque type estimates a mismatch of less than 8% in the analysed frames.

Selective fabrication of iron oxide particles in halloysite lumen

International Nuclear Information System (INIS)

Zheng, Pengwu; Du, Yuanyuan; Ma, Xiaofei

2015-01-01

As the adsorbents or the supports of photocatalysts, halloysite nanotubes (HNT) were expected to have intact external surface for adsorption or catalyst immobilization, when Fe 3 O 4 particles was introduced to prepare magnetic HNTs for easy separation. The negatively charged urease was loaded inside positively charged HNT lumen, and urease catalyzed the hydrolysis of urea and resulted in the alkaline environment in HNT lumen. When Fe 3+ and Fe 2+ diffused in, Fe 3 O 4 particles were selectively synthesized in the lumen of HNT. The obtained Fe 3 O 4 @HNT is characterized by transmission electron microscopy and Fourier transform infrared spectroscopy, X-ray diffraction and hysteresis loops. The obtained magnetic Fe 3 O 4 @HNT can be magnetically collected with intact external surface, which can support photocatalysts or remove the pollutants. - Highlights: • Fe 3 O 4 @HNT was prepared. • Fe 3 O 4 @HNT was characterized. • Fe 3 O 4 particles were selectively synthesized in the lumen of HNT

Assessment of vertebral artery stents using 16-slice multi-detector row CT angiography in vivo evaluation: Comparison of a medium-smooth kernel and a sharp kernel

International Nuclear Information System (INIS)

Yoo, Won Jong; Lim, Yeon Soo; Ahn, Kook Jin; Choi, Byung Gil; Kim, Ji Young; Kim, Sung Hoon

2009-01-01

Objectives: To assess the lumen visibility of extracranial vertebral artery stents examined with 16-slice multi-detector row computed tomography (MDCT) angiography in vivo using a medium-smooth kernel (B30s) and a sharp kernel (B60s), and to compare these with digital subtraction angiography (DSA) after stent placement. Methods: Twenty stents from 20 patients (14 men, 6 women; mean age, 62.7 ± 10.1 years) who underwent CT angiography (CTA) with 16-slice MDCT were retrospectively analyzed. In CT angiograms using a B30s and a B60s, the lumen diameters and CT attenuations of the stented vessels were measured three times by three observers, and artificial luminal narrowing (ALN) was calculated. To assess measurement reliability on CT angiograms, the intraclass correlation coefficient (ICC) was used. DSA served as the reference standard for the in-stent luminal measurements on CT angiography. The median interval between CT angiography and DSA was 1 day (range 1-10). Results: For interobserver reliability, intraclass correlation coefficients for the lumen diameters on CT angiograms with a B30s and a B60s were 0.90 and 0.96, respectively. The lumen diameters on CT angiograms using a B30s were consistently smaller than that on CT angiograms using a B60s (p < 0.01). The mean ALN was 37 ± 7% on CT angiograms using a B30s and 25 ± 9% on CT angiograms using a B60s. The mean CT attenuation in in-stent lumen was 347 ± 55 HU on CT angiograms using a B30s and 295 ± 46 HU on CT angiograms using a B60s. The ALN and CT attenuation within the stented vessels between CT angiograms using a B30s and a B60s was significant (p < 0.01). Conclusions: 16-slice MDCT using a sharp kernel allows good visualization of the stented vessels and is useful in the assessment of vertebral artery stent patency after stent placement.

Chapter 16 Lumen Modification

Science.gov (United States)

Rebecca E. Ibach; Roger M. Rowell

2012-01-01

When wood is vacuum impregnated with liquid vinyl monomers that do not swell wood, and then in situ polymerized either by chemical catalyst-heat, or gamma radiation, the polymer is located almost solely in the lumens of the wood. Figure 16.1 is a scanning electron microscopy (SEM) micrograph of unmodified wood showing open cells that are...

Neutrophil-Mediated Delivery of Therapeutic Nanoparticles across Blood Vessel Barrier for Treatment of Inflammation and Infection

OpenAIRE

Chu, Dafeng; Gao, Jin; Wang, Zhenjia

2015-01-01

Endothelial cells form a monolayer in lumen of blood vessels presenting a great barrier for delivery of therapeutic nanoparticles (NPs) into extravascular tissues where most diseases occur, such as inflammation disorders and infection. Here, we report a strategy for delivering therapeutic NPs across this blood vessel barrier by nanoparticle in situ hitchhiking activated neutrophils. Using intravital microscopy of TNF-α-induced inflammation of mouse cremaster venules and a mouse model of acute...

Obesity and overweight associated with increased carotid diameter and decreased arterial function in young otherwise healthy men.

Science.gov (United States)

Kappus, Rebecca M; Fahs, Christopher A; Smith, Denise; Horn, Gavin P; Agiovlasitis, Stomatis; Rossow, Lindy; Jae, Sae Y; Heffernan, Kevin S; Fernhall, Bo

2014-04-01

Obesity is linked to cardiovascular disease, stroke, increased mortality and vascular remodeling. Although increased arterial diameter is associated with multiple cardiovascular risk factors and obesity, it is unknown whether lumen enlargement is accompanied by unfavorable vascular changes in young and otherwise healthy obese individuals. The purpose of this study was to compare carotid and brachial artery diameter, blood pressure, arterial stiffness, and endothelial function in young, apparently healthy, normal-weight, overweight, and obese male subjects. One hundred sixty-five male subjects (27.39±0.59 years) were divided into 3 groups (normal weight, overweight, and obese) according to body mass index. Subjects underwent cardiovascular measurements to determine arterial diameter, function, and stiffness. After adjusting for age, the obese group had significantly greater brachial, carotid, and aortic pressures, brachial pulse wave velocity, carotid intima media thickness, and carotid arterial diameter compared with both the overweight and normal-weight groups. Obesity is associated with a much worse arterial profile, as an increased carotid lumen size was accompanied by higher blood pressure, greater arterial stiffness, and greater carotid intima media thickness in obese compared with overweight or normal-weight individuals. These data suggest that although obesity may be a factor in arterial remodeling, such remodeling is also accompanied by other hemodynamic and arterial changes consistent with reduced arterial function and increased cardiovascular risk.

Chronic binge alcohol consumption during pregnancy alters rat maternal uterine artery pressure response.

Science.gov (United States)

Naik, Vishal D; Lunde-Young, Emilie R; Davis-Anderson, Katie L; Orzabal, Marcus; Ivanov, Ivan; Ramadoss, Jayanth

2016-11-01

We aimed to investigate pressure-dependent maternal uterine artery responses and vessel remodeling following gestational binge alcohol exposure. Two groups of pregnant rats were used: the alcohol group (28.5% wt/v, 6.0 g/kg, once-daily orogastric gavage in a binge paradigm between gestational day (GD) 5-19) and pair-fed controls (isocalorically matched). On GD20, excised, pressurized primary uterine arteries were studied following equilibration (60 mm Hg) using dual chamber arteriograph. The uterine artery diameter stabilized at 20 mm Hg, showed passive distension at 40 mm Hg, and redeveloped tone at 60 mm Hg. An alcohol effect (P = 0.0025) was observed on the percent constriction of vessel diameter with greater pressure-dependent myogenic constriction. Similar alcohol effect was noted with lumen diameter response (P = 0.0020). The percent change in media:lumen ratio was higher in the alcohol group (P alcohol affects pressure-induced uterine artery reactivity, inward-hypotrophic remodeling, and adaptations critical for nutrient delivery to the fetus. Copyright © 2016 Elsevier Inc. All rights reserved.

Selective fabrication of iron oxide particles in halloysite lumen

Energy Technology Data Exchange (ETDEWEB)

Zheng, Pengwu; Du, Yuanyuan [School of Pharmacy, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi 330013 (China); Ma, Xiaofei, E-mail: maxiaofei@tju.edu.cn [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China)

2015-02-01

As the adsorbents or the supports of photocatalysts, halloysite nanotubes (HNT) were expected to have intact external surface for adsorption or catalyst immobilization, when Fe{sub 3}O{sub 4} particles was introduced to prepare magnetic HNTs for easy separation. The negatively charged urease was loaded inside positively charged HNT lumen, and urease catalyzed the hydrolysis of urea and resulted in the alkaline environment in HNT lumen. When Fe{sup 3+} and Fe{sup 2+} diffused in, Fe{sub 3}O{sub 4} particles were selectively synthesized in the lumen of HNT. The obtained Fe{sub 3}O{sub 4}@HNT is characterized by transmission electron microscopy and Fourier transform infrared spectroscopy, X-ray diffraction and hysteresis loops. The obtained magnetic Fe{sub 3}O{sub 4}@HNT can be magnetically collected with intact external surface, which can support photocatalysts or remove the pollutants. - Highlights: • Fe{sub 3}O{sub 4}@HNT was prepared. • Fe{sub 3}O{sub 4}@HNT was characterized. • Fe{sub 3}O{sub 4} particles were selectively synthesized in the lumen of HNT.

ICAM-1 and VCAM-1 expression by endothelial cells grown on fibronectin-coated TCPS and PS

NARCIS (Netherlands)

van der Zijpp, Y.J.T.; Poot, Andreas A.; Feijen, Jan

2003-01-01

Small-diameter vascular grafts rapidly fail as a result of blood coagulation and platelet deposition. Endothelial cells lining the inner side of blood vessels can provide the graft lumen with an antithrombogenic surface. One of the remaining problems is cell detachment after restoration of blood

Sonographic study about differential diagnosis between acute appendicitis and non-appendicitis in appendices of borderline diameter

International Nuclear Information System (INIS)

Chung, Hwan Hoon; Kim, Yun Hwan; Kim, Hong Won; Park, Seung Cheol; Lee, Eun Jeong; Chung, Kyoo Byung; Suh, Won Hyuck

2000-01-01

To find out the sonographic criteria which can be effectively used to differentiate acute appendicitis from non-appendicitis in patients with appendices with borderline diameter(5-8 mm). Sixteen patients diagnosed as acute appendicitis, another 16 patients diagnosed as non-appendicitis were included in this study. They complained of RLQ pain and their appendices measured 5-8 mm in diameter on sonogram. Features such as appendiceal wall thickness, presence or absence of air in appendiceal lumen, movability of tip of the appendix, compressibility of the appendix were evaluated on gray-scale sonogram and thereafter, presence or absence of color flow in the wall of the appendix was evaluated on color Doppler sonogram. Thickness of appendiceal wall is 2.98 ± 0.77 mm in acute appendicitis group and 1.73 ± 0.44 mm in non-appendicitis group (p<0.05). When 2.5 mm thickness of appendiceal wall is applied for diagnosis of acute appendicitis, sensitivity is 81.3%, specificity is 87.5% and accuracy is 84.4%. With absence of air in appendiceal lumen, sensitivity is 93.8%, specificity is 68.8% and accuracy is 81.3%. With absence of movability of appendiceal tip, sensitivity is 87.5%, specificity is 50% and accuracy is 68.8%. With absence of compressibility of the appendix, sensitivity is 100%, specificity is 31.3% and accuracy is 65.6%. With color flow in appendiceal wall, sensitivity is 81.3%, specificity is 62.5% and accuracy is 71.9%. The above mentioned criteria show statistically significant difference between acute appendicitis and non-appendicitis groups (p<0.05). When the diameter of the appendix measures 5-8 mm on sonogram, evaluation of thickness of appendiceal wall, air in appendiceal lumen, movability of tip, compressibility and color flow in the wall will be helpful to diagnose the acute appendicitis with confidence.

MR Angiography of Peripheral Arterial Stents: In Vitro Evaluation of 22 Different Stent Types

Directory of Open Access Journals (Sweden)

Matthias C. Burg

2011-01-01

Full Text Available Purpose. To evaluate stent lumen visibility of a large sample of different peripheral arterial (iliac, renal, carotid stents using magnetic resonance angiography in vitro. Materials and Methods. 21 different stents and one stentgraft (10 nitinol, 7 316L, 2 tantalum, 1 cobalt superalloy, 1 PET + cobalt superalloy, and 1 platinum alloy were examined in a vessel phantom (vessel diameters ranging from 5 to 13 mm filled with a solution of Gd-DTPA. Stents were imaged at 1.5 Tesla using a T1-weighted 3D spoiled gradient-echo sequence. Image analysis was performed measuring three categories: Signal intensity in the stent lumen, lumen visibility of the stented lumen, and homogeneity of the stented lumen. The results were classified using a 3-point scale (good, intermediate, and poor results. Results. 7 stents showed good MR lumen visibility (4x nitinol, 2x tantalum, and 1x cobalt superalloy. 9 stents showed intermediate results (5x nitinol, 2x 316L, 1x PET + cobalt superalloy, and 1x platinum alloy and 6 stents showed poor results (1x nitinol, and 5x 316L. Conclusion. Stent lumen visibility varies depending on the stent material and type. Some products show good lumen visibility which may allow the detection of stenoses inside the lumen, while other products cause artifacts which prevent reliable evaluation of the stent lumen with this technique.

Anatomic vascular phantom for the verification of MRA and XRA visualization and fusion

International Nuclear Information System (INIS)

Mankovich, N.J.; Lambert, T.; Zrimec, T.; Hiller, J.

1995-01-01

A project is underway to develop automated methods of fusing cerebral magnetic resonance angiography (MRA) and x-ray angiography (XRA) for creating accurate visualizations used in planning treatment of vascular disease. The authors have developed a vascular phantom suitable for testing segmentation and fusion algorithms with either derived images (pseudo-MRA/pseudo-XRA) or actual MRA or XRA image sequences. The initial unilateral arterial phantom design, based on normal human anatomy, contains 48 tapering vascular segments with lumen diameters from 2.5 millimeter to 0.25 millimeter. The initial phantom used rapid prototyping technology (stereolithography) with a 0.9 millimeter vessel wall fabricated in an ultraviolet-cured plastic. The model fabrication resulted in a hollow vessel model comprising the internal carotid artery, the ophthalmic artery, and the proximal segments of the anterior, middle, and posterior cerebral arteries. The complete model was fabricated but the model's lumen could not be cleared for vessels with less than 1 millimeter diameter. Measurements of selected vascular outer diameters as judged against the CAD specification showed an accuracy of 0.14 mm and precision (standard deviation) of 0.15 mm. The plastic vascular model produced provides a fixed geometric framework for the evaluation of imaging protocols and the development of algorithms for both segmentation and fusion

Stanford type A aortic dissection with closed false lumen: Analysis of prognostic factors at initial CT or MRI

Energy Technology Data Exchange (ETDEWEB)

Matsuoka, Yohjiro; Sakamoto, Ichiro; Ogawa, Yohji; Sueyoshi, Eijun; Hayashi, Kuniaki; Takagi, Masatake [Nagasaki Univ. (Japan). School of Medicine; Narimatsu, Motoharu

1997-08-01

Nineteen patients with Stanford type A acute aortic dissection with closed false lumen were reviewed. In the follow-up examinations, ulcerlike projection (ULP) in the ascending aorta (AA) or aortic arch (AR) was identified in 8 of 19 patients. In 5 of these 8 patients, acute cardiac tamponade occurred and 3 of them died. In the other 11 patients, there was no mortality, and only one patient underwent elective surgery. The appearance of ULP in the AA/AR is considered an indication for urgent surgery because it is regarded as a precursor of lethal complications such as cardiac tamponade. The purpose of this study was to investigate predictors of the appearance of ULP in the AA/AR with early imagings (CT or MRI) before the appearance of ULP. The patients were divided into two groups: patients with ULP in the AA/AR (8 patients) and others (11 patients). Initial CT or MRI findings of the thoracic aorta were retrospectively statistically analyzed in each group. Three predictive factors were statistically significant for the appearance of ULP in the AA/AR (diameter of the AA{>=}5 cm, thickness of the false lumen of the AA{>=}1 cm, thickness of the false lumen of the AA{>=} that of the descending aorta). Close attention should be paid, if any of these 3 factors is observed at initial CT or MRI. (author)

Stanford type A aortic dissection with closed false lumen: Analysis of prognostic factors at initial CT or MRI

International Nuclear Information System (INIS)

Matsuoka, Yohjiro; Sakamoto, Ichiro; Ogawa, Yohji; Sueyoshi, Eijun; Hayashi, Kuniaki; Takagi, Masatake; Narimatsu, Motoharu.

1997-01-01

Nineteen patients with Stanford type A acute aortic dissection with closed false lumen were reviewed. In the follow-up examinations, ulcerlike projection (ULP) in the ascending aorta (AA) or aortic arch (AR) was identified in 8 of 19 patients. In 5 of these 8 patients, acute cardiac tamponade occurred and 3 of them died. In the other 11 patients, there was no mortality, and only one patient underwent elective surgery. The appearance of ULP in the AA/AR is considered an indication for urgent surgery because it is regarded as a precursor of lethal complications such as cardiac tamponade. The purpose of this study was to investigate predictors of the appearance of ULP in the AA/AR with early imagings (CT or MRI) before the appearance of ULP. The patients were divided into two groups: patients with ULP in the AA/AR (8 patients) and others (11 patients). Initial CT or MRI findings of the thoracic aorta were retrospectively statistically analyzed in each group. Three predictive factors were statistically significant for the appearance of ULP in the AA/AR (diameter of the AA≥5 cm, thickness of the false lumen of the AA≥1 cm, thickness of the false lumen of the AA≥ that of the descending aorta). Close attention should be paid, if any of these 3 factors is observed at initial CT or MRI. (author)

Intravascular drug delivery with a pulsed liquid microjet.

Science.gov (United States)

Fletcher, Daniel A; Palanker, Daniel V; Huie, Philip; Miller, Jason; Marmor, Michael F; Blumenkranz, Mark S

2002-09-01

Occlusions of the retinal veins and arteries, associated with diseases such as hypertension and arteriosclerosis, are a major cause of severe and irreversible loss of vision. Treatments for retinal vascular diseases have been unsatisfactory owing in part to the difficulty of delivering drugs to the site of disease within the eye. In this article, we demonstrate that a new device, the vapor bubble-driven pulsed liquid microjet, can deliver drugs into the lumen of small vessels such as those found in the retina. A 15- micro m-diameter liquid jet traveling at more than 60 m/s was shown to penetrate and deliver fluid through the wall of a blood vessel that was 60 micro m in diameter. Perforation of the wall of the blood vessel did not extend beyond the jet diameter.

Variable impact of CSF flow suppression on quantitative 3.0T intracranial vessel wall measurements.

Science.gov (United States)

Cogswell, Petrice M; Siero, Jeroen C W; Lants, Sarah K; Waddle, Spencer; Davis, L Taylor; Gilbert, Guillaume; Hendrikse, Jeroen; Donahue, Manus J

2018-03-31

Flow suppression techniques have been developed for intracranial (IC) vessel wall imaging (VWI) and optimized using simulations; however, simulation results may not translate in vivo. To evaluate experimentally how IC vessel wall and lumen measurements change in identical subjects when evaluated using the most commonly available blood and cerebrospinal fluid (CSF) flow suppression modules and VWI sequences. Prospective. Healthy adults (n = 13; age = 37 ± 15 years) were enrolled. A 3.0T 3D T 1 /proton density (PD)-weighted turbo-spin-echo (TSE) acquisition with post-readout anti-driven equilibrium module, with and without Delay-Alternating-with-Nutation-for-Tailored-Excitation (DANTE) was applied. DANTE flip angle (8-12°) and TSE refocusing angle (sweep = 40-120° or 50-120°) were varied. Basilar artery and internal carotid artery (ICA) wall thicknesses, CSF signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and signal ratio (SR) were assessed. Measurements were made by two readers (radiology resident and board-certified neuroradiologist). A Wilcoxon signed-rank test was applied with corrected two-sided P CSF suppression. Addition of the DANTE preparation reduced CSF SNR from 17.4 to 6.7, thereby providing significant (P CSF suppression. The DANTE preparation also resulted in a significant (P CSF CNR improvement (P = 0.87). There was a trend for a difference in blood SNR with vs. without DANTE (P = 0.05). The outer vessel wall diameter and wall thickness values were lower (P CSF suppression and CNR of the approaches evaluated. However, improvements are heterogeneous, likely owing to intersubject vessel pulsatility and CSF flow variations, which can lead to variable flow suppression efficacy in these velocity-dependent modules. 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018. © 2018 International Society for Magnetic Resonance in Medicine.

Multiple cell common pressure vessel nickel hydrogen battery

Science.gov (United States)

Zagrodnik, Jeffrey P.; Jones, Kenneth R.

1991-01-01

A multiple cell common pressure vessel (CPV) nickel hydrogen battery was developed that offers significant weight, volume, cost, and interfacing advantages over the conventional individual pressure vessel (IPV) nickel hydrogen configuration that is currently used for aerospace applications. The baseline CPV design was successfully demonstrated though the testing of a 26 cell prototype, which completed over 7,000 44 percent depth of discharge LEO cycles. Two-cell boilerplate batteries have now exceeded 12,500 LEO cycles in ongoing laboratory tests. CPV batteries using both nominal 5 and 10 inch diameter vessels are currently available. The flexibility of the design allows these diameters to provide a broad capability for a variety of space applications.

Preparation of lumen-loaded kenaf pulp with magnetite (Fe3O4)

International Nuclear Information System (INIS)

Zakaria, S.; Ong, B.H.; Ahmad, S.H.; Abdullah, M.; Yamauchi, T.

2005-01-01

Magnetic pulps were prepared from unbleached kenaf (hibiscus cannabinus L.) kraft pulps. Fe 3 O 4 or magnetite powder was used to load into the pulp's lumen and pit. Aluminum sulphate [Al 2 (SO 4 ) 3 ] (alum) and polyethylenimine (PEI), both mainly function as retention aid were used throughout the experiment and found to be beneficial in the preparation of this magnetic pulps. The ash content method was used to determine the amount of magnetite retained in the lumen and pit. The utilization of PEI up to 2% per pulp fibres was found to be the best result on lumen loading. The deposition of magnetite powder in lumen and pit is found decrease as the addition of PEI used is more than 2% per pulp fibres. Scanning electron microscope (SEM) clearly shows the distribution of magnetite deposited in the lumen. Tensile index and folding endurance of the loaded fibre decreased slightly as the percentage of loading pigment increased

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.

Assessment of W7-X plasma vessel pressurisation in case of LOCA taking into account in-vessel components

International Nuclear Information System (INIS)

Urbonavičius, E.; Povilaitis, M.; Kontautas, A.

2015-01-01

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.

Hollow fiber membrane lumen modified by polyzwitterionic grafting

KAUST Repository

Le, Ngoc Lieu

2016-08-24

In this study, we demonstrate an effective way to modify the lumen of polyetherimide hollow fibers by grafting zwitterionic poly(sulfobetaine) to increase the membrane resistance to fouling. Surface-selective grafting of the protective hydrogel layers has been achieved in a facile two-step process. The first step is the adsorption of a macromolecular redox co-initiator on the lumen-side surface of the membrane, which in the second step, after flushing the lumen of the membrane with a solution comprising monomers and a complementary redox initiator, triggers the in situ cross-linking copolymerization at room temperature. The success of grafting reaction has been verified by the surface elemental analyses using X-ray photoelectron spectroscopy (XPS) and the surface charge evaluation using zeta potential measurements. The hydrophilicity of the grafted porous substrate is improved as indicated by the change of contact angle value from 44° to 30°, due to the hydration layer on the surface produced by the zwitterionic poly(sulfobetaine). Compared to the pristine polyetherimide (PEI) substrate, the poly(sulfobetaine) grafted substrates exhibit high fouling resistance against bovine serum albumin (BSA) adsorption, E. coli attachment and cell growth on the surface. Fouling minimization in the lumen is important for the use of hollow fibers in different processes. For instance, it is needed to preserve power density of pressure-retarded osmosis (PRO). In high-pressure PRO tests, a control membrane based on PEI with an external polyamide selective layer was seriously fouled by BSA, leading to a high water flux drop of 37%. In comparison, the analogous membrane, whose lumen was modified with poly(sulfobetaine), not only had a less water flux decline but also had better flux recovery, up to 87% after cleaning and hydraulic pressure impulsion. Clearly, grafting PRO hollow fiber membranes with zwitterionic polymeric hydrogels as a protective layer potentially sustains PRO

Scaling of Engineered Vascular Grafts Using 3D Printed Guides and the Ring Stacking Method.

Science.gov (United States)

Pinnock, Cameron B; Xu, Zhengfan; Lam, Mai T

2017-03-27

Coronary artery disease remains a leading cause of death, affecting millions of Americans. With the lack of autologous vascular grafts available, engineered grafts offer great potential for patient treatment. However, engineered vascular grafts are generally not easily scalable, requiring manufacture of custom molds or polymer tubes in order to customize to different sizes, constituting a time-consuming and costly practice. Human arteries range in lumen diameter from about 2.0-38 mm and in wall thickness from about 0.5-2.5 mm. We have created a method, termed the "Ring Stacking Method," in which variable size rings of tissue of the desired cell type, demonstrated here with vascular smooth muscle cells (SMCs), can be created using guides of center posts to control lumen diameter and outer shells to dictate vessel wall thickness. These tissue rings are then stacked to create a tubular construct, mimicking the natural form of a blood vessel. The vessel length can be tailored by simply stacking the number of rings required to constitute the length needed. With our technique, tissues of tubular forms, similar to a blood vessel, can be readily manufactured in a variety of dimensions and lengths to meet the needs of the clinic and patient.

Automated quantification of bronchiectasis, airway wall thickening and lumen tapering in chest CT

DEFF Research Database (Denmark)

Perez-Rovira, Adria; Kuo, Wieying; Petersen, Jens

thickness and accompanying artery radius), and inter-branch Lumen-Ratio (LR, ratio between a branch's lumen and its parent branch lumen radius, a tapering measurement) were computed. Because CF-related structural abnormalities only affect a portion of branches, the 75th percentile was used as summarising......Purpose: To automatically quantify airway structural properties visualised on CT in children with cystic fibrosis (CF) and controls, including: bronchiectasis, airway wall thickening, and lumen tapering. Methods and materials: The 3D surface of the airway lumen, outer wall, and bronchial arteries...... were obtained using a fully automatic, in-house developed, segmentation method. Subsequently, for each detected airway branch, the Airway-Artery Ratio (AAR, ratio between airway outer wall and accompanying artery radius, a bronchiectasis measurement), Wall-Artery Ratio (WAR, ratio between airway wall...

Heissdampfreaktor (HDR) steel-containment-vessel and floodwater-storage-tank structural-dynamics tests

International Nuclear Information System (INIS)

Arendts, J.G.

1982-01-01

Inertance (vibration) testing of two significant vessels at the Heissdampfreaktor (HDR) facility, located near Kahl, West Germany, was recently completed. Transfer functions were obtained for determination of the modal properties (frequencies, mode shapes and damping) of the vessels using two different test methods for comparative purposes. One of the vessels tested was the steel containment vessel (SCV). The SCV is approximately 180 feet high and 65 feet in diameter with a 1.2-inch wall thickness. The other vessel, called the floodwater storage tank (FWST), is a vertically standing vessel approximately 40 feet high and 10 feet in diameter with a 1/2-inch wall thickness. The FWST support skirt is square (in plan views) with its corners intersecting the ellipsoidal bottom head near the knuckle region

A comparison of hydraulic architecture in three similarly sized woody species differing in their maximum potential height

Science.gov (United States)

Katherine A. McCulloh; Daniel M. Johnson; Joshua Petitmermet; Brandon McNellis; Frederick C. Meinzer; Barbara Lachenbruch; Nathan Phillips

2015-01-01

The physiological mechanisms underlying the short maximum height of shrubs are not understood. One possible explanation is that differences in the hydraulic architecture of shrubs compared with co-occurring taller trees prevent the shrubs from growing taller. To explore this hypothesis, we examined various hydraulic parameters, including vessel lumen diameter,...

Fluid-solid contact vessel having fluid distributors therein

Science.gov (United States)

Jones, Jr., John B.

1980-09-09

Rectangularly-shaped fluid distributors for large diameter, vertical vessels include reinforcers for high heat operation, vertical sides with gas distributing orifices and overhanging, sloped roofs. Devices are provided for cleaning the orifices from a buildup of solid deposits resulting from the reactions in the vessel.

Construction of tissue-engineered small-diameter vascular grafts in fibrin scaffolds in 30 days.

Science.gov (United States)

Gui, Liqiong; Boyle, Michael J; Kamin, Yishai M; Huang, Angela H; Starcher, Barry C; Miller, Cheryl A; Vishnevetsky, Michael J; Niklason, Laura E

2014-05-01

Tissue-engineered small-diameter vascular grafts have been developed as a promising alternative to native veins or arteries for replacement therapy. However, there is still a crucial need to improve the current approaches to render the tissue-engineered blood vessels more favorable for clinical applications. A completely biological blood vessel (3-mm inner diameter) was constructed by culturing a 50:50 mixture of bovine smooth muscle cells (SMCs) with neonatal human dermal fibroblasts in fibrin gels. After 30 days of culture under pulsatile stretching, the engineered blood vessels demonstrated an average burst pressure of 913.3±150.1 mmHg (n=6), a suture retention (53.3±15.4 g) that is suitable for implantation, and a compliance (3.1%±2.5% per 100 mmHg) that is comparable to native vessels. These engineered grafts contained circumferentially aligned collagen fibers, microfibrils and elastic fibers, and differentiated SMCs, mimicking a native artery. These promising mechanical and biochemical properties were achieved in a very short culture time of 30 days, suggesting the potential of co-culturing SMCs with fibroblasts in fibrin gels to generate functional small-diameter vascular grafts for vascular reconstruction surgery.

Multiple versus single lumen umbilical venous catheters for newborn infants.

Science.gov (United States)

Kabra, N S; Kumar, M; Shah, S S

2005-07-20

needed to treat (NNT) or number needed to harm (NNH) was calculated. Three studies qualified for inclusion in this review (Khilnani 1991; Loisel 1996; Soupre 1998). There was a decrease in the ML-UVCs group in the number of additional PIVs used in the first week of life [WMD -1.42, (95% CI -1.74, -1.10), pcatheter malfunction in the ML-UVCs group [typical RR 3.69 (95% CI 0.99, 13.81), p=0.05; RD 0.15 (95% CI 0.03, 0.27), p=0.01; NNH was 7, 95% CI 4, 33; n=99]. The following outcomes were not significantly different in the two groups: clinical sepsis, catheter related blood stream infection, catheter-associated thrombosis, complications related to catheter malposition in heart and great vessels, NEC and early neonatal mortality. The use of ML-UVCs in comparison to SL-UVCs in neonates is associated with decrease in the usage of PIVs in first week of life, but an increase in catheter malfunctions. As the quality of included randomized studies is poor and the estimates of clinically important complications are imprecise, no firm recommendations can be made regarding the choice of UVC. Adequately powered, properly randomized and properly blinded controlled trials are needed that address the effectiveness and safety of ML-UVCs (double and triple lumen) in comparison to SL-UVCs. These studies should also address the impact of type of catheter material.

Joint segmentation of lumen and outer wall from femoral artery MR images: Towards 3D imaging measurements of peripheral arterial disease.

Science.gov (United States)

Ukwatta, Eranga; Yuan, Jing; Qiu, Wu; Rajchl, Martin; Chiu, Bernard; Fenster, Aaron

2015-12-01

Three-dimensional (3D) measurements of peripheral arterial disease (PAD) plaque burden extracted from fast black-blood magnetic resonance (MR) images have shown to be more predictive of clinical outcomes than PAD stenosis measurements. To this end, accurate segmentation of the femoral artery lumen and outer wall is required for generating volumetric measurements of PAD plaque burden. Here, we propose a semi-automated algorithm to jointly segment the femoral artery lumen and outer wall surfaces from 3D black-blood MR images, which are reoriented and reconstructed along the medial axis of the femoral artery to obtain improved spatial coherence between slices of the long, thin femoral artery and to reduce computation time. The developed segmentation algorithm enforces two priors in a global optimization manner: the spatial consistency between the adjacent 2D slices and the anatomical region order between the femoral artery lumen and outer wall surfaces. The formulated combinatorial optimization problem for segmentation is solved globally and exactly by means of convex relaxation using a coupled continuous max-flow (CCMF) model, which is a dual formulation to the convex relaxed optimization problem. In addition, the CCMF model directly derives an efficient duality-based algorithm based on the modern multiplier augmented optimization scheme, which has been implemented on a GPU for fast computation. The computed segmentations from the developed algorithm were compared to manual delineations from experts using 20 black-blood MR images. The developed algorithm yielded both high accuracy (Dice similarity coefficients ≥ 87% for both the lumen and outer wall surfaces) and high reproducibility (intra-class correlation coefficient of 0.95 for generating vessel wall area), while outperforming the state-of-the-art method in terms of computational time by a factor of ≈ 20. Copyright © 2015 Elsevier B.V. All rights reserved.

Computed tomography airway lumen volumetry in patients with acromegaly: Association with growth hormone levels and lung function.

Science.gov (United States)

Camilo, Gustavo Bittencourt; Carvalho, Alysson Roncally Silva; Guimarães, Alan Ranieri Medeiros; Kasuki, Leandro; Gadelha, Mônica Roberto; Mogami, Roberto; de Melo, Pedro Lopes; Lopes, Agnaldo José

2017-10-01

The segmentation and skeletonisation of images via computed tomography (CT) airway lumen volumetry provide a new perspective regarding the incorporation of this technique in medical practice. Our aim was to quantify morphological changes in the large airways of patients with acromegaly through CT and, secondarily, to correlate these findings with hormone levels and pulmonary function testing (PFT) parameters. This was a cross-sectional study in which 28 non-smoker patients with acromegaly and 15 control subjects underwent CT analysis of airway lumen volumetry with subsequent image segmentation and skeletonisation. Moreover, all participants were subjected to PFT. Compared with the controls, patients with acromegaly presented higher diameters in the trachea, right main bronchus and left main bronchus. The patients with acromegaly also showed a higher tracheal sinuosity index (the deviation of a line from the shortest path, calculated by dividing total length by shortest possible path) than the controls [1.06 (1.02-1.09) vs. 1.03 (1.02-1.04), P = 0.04], and tracheal stenosis was observed in 25% of these individuals. The tracheal area was correlated with the levels of growth hormone (r s  = 0.45, P = 0.02) and insulin-like growth factor type I (r s  = 0.38, P = 0.04). The ratio between the forced expiratory flow and forced inspiratory flow at 50% of the forced vital capacity was correlated with the tracheal area (r s  = 0.36, P = 0.02) and Δ tracheal diameters (r s  = 0.58, P volumetry, hormone levels and functional parameters of large airway obstruction. © 2017 The Royal Australian and New Zealand College of Radiologists.

A model for ultrasound contrast agent in a phantom vessel

KAUST Repository

Qamar, Adnan

2014-02-01

A theoretical framework to model the dynamics of Ultrasound Contrast Agent (UCA) inside a phantom vessel is presented. The model is derived from the reduced Navier-Stokes equation and is coupled with the evolving flow field solution inside the vessel by a similarity transformation approach. The results are computed, and compared with experiments available in literature, for the initial UCA radius of Ro=1.5 μm and 2 μm for the vessel diameter of D=12 μm and 200 μm with the acoustic parameters as utilized in the experiments. When compared to other models, better agreement on smaller vessel diameter is obtained with the proposed coupled model. The model also predicts, quite accurately, bubble fragmentation in terms of acoustic and geometric parameters. © 2014 IEEE.

Fate of the dissecting lumen by CT study following surgical repair

Energy Technology Data Exchange (ETDEWEB)

Nakajima, Nobuyuki; Ando, Taizo; Kawazoe, Kohei; Tomino, Tetsuo; Fujita, Takeshi; Naito, Hiroaki; Yamaguchi, Toshio

1983-03-01

A postoperative follow-up study on the fate of dissecting lumen by means of computer tomography has been evaluated. The materials were 21 patients who underwent surgery for dissection of the aorta, including 8 patients in type 1 of DeBakey classification, 3 in type 11, 8 in type 111 and 2 patients of localized dissection in descending and abdominal aorta. The susceptibility for thrombus formation in dissecting lumen appeared to be related to the background etiology of dissection where poor tendency for thrombus formation was observed in a group of patients with Marfan syndrome and its' incomplete form. On the other hand in the group of patients who had a history of hypertension and atherosclerosis probable, a strong tendency of thrombus formation and eventual occlusion of lumen was obtained. On the basis of above findings, it will be said that the surgical intervention for type 1 of DeBakey classification in Marfan patient is merely creating type 111 dissection, closed observation in the future change of dissecting lumen is of utmost importance especially in those groups of patients.

Fate of the dissecting lumen by CT study following surgical repair

International Nuclear Information System (INIS)

Nakajima, Nobuyuki; Ando, Taizo; Kawazoe, Kohei; Tomino, Tetsuo; Fujita, Takeshi; Naito, Hiroaki; Yamaguchi, Toshio.

1983-01-01

A postoperative follow-up study on the fate of dissecting lumen by mean of computer tomography has been evaluated. The materials were 21 patients who underwent surgery for dissection of the aorta, including 8 patients in type 1 of DeBakey classification, 3 in type 11, 8 in type 111 and 2 patients of localized dissection in descending and abdominal aorta. The susceptibility for thrombus formation in dissecting lumen appeared to be relating to the background etiology of dissection where poor tendency for thrombus formation was observed in group of patients with Marfan syndrome and its' incomplete form. On the other hand in those group of patients who had a history of hypertension and atherosclerosis probable, a strong tendency of thrombus formation and eventual occlusion of lumen was obtained. On the basis of above findings, it will be said that the surgical intervention for type 1 of DeBakey classification in Marfan patient is merely creating type 111 dissection, closed observation in the future change of dissecting lumen is utmost important especially in those group of patients. (author)

Normal ureteral diameter in infancy and childhood

International Nuclear Information System (INIS)

Hellstroem, M.; Hjaelmaas, K.; Jacobsson, B.; Jodal, U.; Oden, A.; Oestra Sjukhuset, Goeteborg; Oestra Sjukhuset, Goeteborg; Goeteborg Univ.

1985-01-01

Ureteral diameters were estimated on films from intravenous urography in 194 children (100 boys and 94 girls) aged 0-16 years. Children with signs of urinary tract infection, calculi, obstruction, duplication or malformation were excluded. Films obtained without abdominal compression were used for measurements, including only ureters visualized over 50 per cent of their lengths. A good correlation was demonstrated between ureteral diameter and age and between ureteral diameter and the length of a segment of the lumbar spine. The widest part of the ureter was most often located just above the crossing of the iliac vessels. The right ureter was slightly wider than the left one. No difference between boys and girls was noted. The results are in good agreement with those of others obtained at autopsy. Bearing in mind the possible physiologic variations, it would seem that measuring the ureteral diameter can be of value for a more objective differentiation between dilated and non-dilated ureters. (orig.)

Age-Related Changes in Pharyngeal Lumen Size: A Retrospective MRI Analysis.

Science.gov (United States)

Molfenter, Sonja M; Amin, M R; Branski, R C; Brumm, J D; Hagiwara, M; Roof, S A; Lazarus, C L

2015-06-01

Age-related loss of muscle bulk and strength (sarcopenia) is often cited as a potential mechanism underlying age-related changes in swallowing. Our goal was to explore this phenomenon in the pharynx, specifically, by measuring pharyngeal wall thickness and pharyngeal lumen area in a sample of young versus older women. MRI scans of the neck were retrospectively reviewed from 60 women equally stratified into three age groups (20s, 60s, 70+). Four de-identified slices were extracted per scan for randomized, blinded analysis: one mid-sagittal and three axial slices were selected at the anterior inferior border of C2 and C3, and at the pit of the vallecula. Pixel-based measures of pharyngeal wall thickness and pharyngeal lumen area were completed using ImageJ and then converted to metric units. Measures of pharyngeal wall thickness and pharyngeal lumen area were compared between age groups with one-way ANOVAs using Sidak adjustments for post-hoc pairwise comparisons. A significant main effect for age was observed across all variables whereby pharyngeal wall thickness decreased and pharyngeal lumen area increased with advancing age. Pairwise comparisons revealed significant differences between 20s versus 70+ for all variables and 20s versus 60s for all variables except those measured at C2. Effect sizes ranged from 0.54 to 1.34. Consistent with existing sacropenia literature, the pharyngeal muscles appear to atrophy with age and consequently, the size of the pharyngeal lumen increases.

Pressure vessels and methods of sealing leaky tubes disposed in pressure vessels

International Nuclear Information System (INIS)

Larson, G.C.

1980-01-01

This invention relates to pressure vessels and to methods of sealing leaky tubes in them and is especially applicable to pressure vessels in the form of sheet-and-tube type heat exchangers constructed with a large number of relatively small diameter tubes grouped in a bundle. To seal off a leaky tube in such a heat exchanger an explosive activated plug in the form of a hollow metal body is used, inserted at each end of the tube to be sealed. Using the arrangement of pressure vessel and associated tube sheets and the explosive activated plug method of sealing a leaky tube as described in this invention it is claimed that distortion of the adjacent tubes and the tube sheets is reduced when the explosive activated plugs are detonated. (U.K.)

Mural cell associated VEGF is required for organotypic vessel formation.

Directory of Open Access Journals (Sweden)

Lasse Evensen

Full Text Available BACKGROUND: Blood vessels comprise endothelial cells, mural cells (pericytes/vascular smooth muscle cells and basement membrane. During angiogenesis, mural cells are recruited to sprouting endothelial cells and define a stabilizing context, comprising cell-cell contacts, secreted growth factors and extracellular matrix components, that drives vessel maturation and resistance to anti-angiogenic therapeutics. METHODS AND FINDINGS: To better understand the basis for mural cell regulation of angiogenesis, we conducted high content imaging analysis on a microtiter plate format in vitro organotypic blood vessel system comprising primary human endothelial cells co-cultured with primary human mural cells. We show that endothelial cells co-cultured with mural cells undergo an extensive series of phenotypic changes reflective of several facets of blood vessel formation and maturation: Loss of cell proliferation, pathfinding-like cell migration, branching morphogenesis, basement membrane extracellular matrix protein deposition, lumen formation, anastamosis and development of a stabilized capillary-like network. This phenotypic sequence required endothelial-mural cell-cell contact, mural cell-derived VEGF and endothelial VEGFR2 signaling. Inhibiting formation of adherens junctions or basement membrane structures abrogated network formation. Notably, inhibition of mural cell VEGF expression could not be rescued by exogenous VEGF. CONCLUSIONS: These results suggest a unique role for mural cell-associated VEGF in driving vessel formation and maturation.

Geometric Deformations of the Thoracic Aorta and Supra-Aortic Arch Branch Vessels Following Thoracic Endovascular Aortic Repair.

Science.gov (United States)

Ullery, Brant W; Suh, Ga-Young; Hirotsu, Kelsey; Zhu, David; Lee, Jason T; Dake, Michael D; Fleischmann, Dominik; Cheng, Christopher P

2018-04-01

To utilize 3-D modeling techniques to better characterize geometric deformations of the supra-aortic arch branch vessels and descending thoracic aorta after thoracic endovascular aortic repair. Eighteen patients underwent endovascular repair of either type B aortic dissection (n = 10) or thoracic aortic aneurysm (n = 8). Computed tomography angiography was obtained pre- and postprocedure, and 3-D geometric models of the aorta and supra-aortic branch vessels were constructed. Branch angle of the supra-aortic branch vessels and curvature metrics of the ascending aorta, aortic arch, and stented thoracic aortic lumen were calculated both at pre- and postintervention. The left common carotid artery branch angle was lower than the left subclavian artery angles preintervention ( P Supra-aortic branch vessel angulation remains relatively static when proximal landing zones are distal to the left common carotid artery.

In-vessel coolability and steam explosion in Nordic BWRs

Energy Technology Data Exchange (ETDEWEB)

Ma, W.; Li, L.; Hansson, R.; Villanueva, W.; Kudinov, P.; Manickam, L.; Tran, C.-T. (Royal Institute of Technology (KTH) (Sweden))

2011-05-15

The objective of this research is to reduce the uncertainty in quantification of steam explosion risk and in-vessel coolability in the Nordic BWR plants which employ cavity flooding as severe accident management (SAM) strategy. To quantify the coolability of debris bed packed with irregular particles, the friction laws of fluid flow in particulate beds packed with non-spherical particles were investigated on the POMECO-FL test facility, and the experimental data suggest that the Ergun equation is applicable if the effective particle diameter of the particles is represented by the equivalent diameter of the particles, which is the product of Sauter mean diameter and shape factor of the particles. One-way coupling analysis between PECM model for melt pool heat transfer and ANSYS thermo-structural mechanics was performed to analyze the vessel creep, and the results revealed two different modes of vessel failure: a 'ballooning' of the vessel bottom and a 'localized creep' concentrated within the vicinity of the top surface of the melt pool. Single-droplet steam explosion experiments were carried out by using oxidic mixture of WO{sub 3}-CaO, and the results show an apparent difference in steam explosion energetics between the eutectic and non-eutectic melts at low melt superheat (100 deg. C). (Author)

In-vessel coolability and steam explosion in Nordic BWRs

International Nuclear Information System (INIS)

Ma, W.; Li, L.; Hansson, R.; Villanueva, W.; Kudinov, P.; Manickam, L.; Tran, C.-T.

2011-05-01

The objective of this research is to reduce the uncertainty in quantification of steam explosion risk and in-vessel coolability in the Nordic BWR plants which employ cavity flooding as severe accident management (SAM) strategy. To quantify the coolability of debris bed packed with irregular particles, the friction laws of fluid flow in particulate beds packed with non-spherical particles were investigated on the POMECO-FL test facility, and the experimental data suggest that the Ergun equation is applicable if the effective particle diameter of the particles is represented by the equivalent diameter of the particles, which is the product of Sauter mean diameter and shape factor of the particles. One-way coupling analysis between PECM model for melt pool heat transfer and ANSYS thermo-structural mechanics was performed to analyze the vessel creep, and the results revealed two different modes of vessel failure: a 'ballooning' of the vessel bottom and a 'localized creep' concentrated within the vicinity of the top surface of the melt pool. Single-droplet steam explosion experiments were carried out by using oxidic mixture of WO 3 -CaO, and the results show an apparent difference in steam explosion energetics between the eutectic and non-eutectic melts at low melt superheat (100 deg. C). (Author)

Lumen Formation Is an Intrinsic Property of Isolated Human Pluripotent Stem Cells

Directory of Open Access Journals (Sweden)

Kenichiro Taniguchi

2015-12-01

Full Text Available We demonstrate that dissociated human pluripotent stem cells (PSCs are intrinsically programmed to form lumens. PSCs form two-cell cysts with a shared apical domain within 20 hr of plating; these cysts collapse to form monolayers after 5 days. Expression of pluripotency markers is maintained throughout this time. In two-cell cysts, an apical domain, marked by EZRIN and atypical PKCζ, is surrounded by apically targeted organelles (early endosomes and Golgi. Molecularly, actin polymerization, regulated by ARP2/3 and mammalian diaphanous-related formin 1 (MDIA, promotes lumen formation, whereas actin contraction, mediated by MYOSIN-II, inhibits this process. Finally, we show that lumenal shape can be manipulated in bioengineered micro-wells. Since lumen formation is an indispensable step in early mammalian development, this system can provide a powerful model for investigation of this process in a controlled environment. Overall, our data establish that lumenogenesis is a fundamental cell biological property of human PSCs.

Neutron Assay System for Confinement Vessel Disposition

International Nuclear Information System (INIS)

Frame, Katherine C.; Bourne, Mark M.; Crooks, William J.; Evans, Louise; Mayo, Douglas R.; Miko, David K.; Salazar, William R.; Stange, Sy; Valdez, Jose I.; Vigil, Georgiana M.

2012-01-01

Los Alamos National Laboratory has a number of spherical confinement vessels (CVs) remaining from tests involving nuclear materials. These vessels have an inner diameter of 6 feet with 1-inch thick steel walls. The goal of the Confinement Vessel Disposition (CVD) project is to remove debris and reduce contamination inside the CVs. The Confinement Vessel Assay System (CVAS) was developed to measure the amount of special nuclear material (SNM) in CVs before and after cleanout. Prior to cleanout, the system will be used to perform a verification measurement of each vessel. After cleanout, the system will be used to perform safeguards-quality assays of (le)100-g 239 Pu equivalent in a vessel for safeguards termination. The CVAS has been tested and calibrated in preparation for verification and safeguards measurements.

Retinal vessel diameter and estimated cerebrospinal fluid pressure in arterial hypertension: the Beijing Eye Study.

Science.gov (United States)

Jonas, Jost B; Wang, Ningli; Wang, Shuang; Wang, Ya Xing; You, Qi Sheng; Yang, Diya; Wei, Wen Bin; Xu, Liang

2014-09-01

Hypertensive retinal microvascular abnormalities include an increased retinal vein-to-artery diameter ratio. Because central retinal vein pressure depends on cerebrospinal fluid pressure (CSFP), we examined whether the retinal vein-to-artery diameter ratio and other retinal hypertensive signs are associated with CSFP. Participants of the population-based Beijing Eye Study (n = 1,574 subjects) underwent measurement of the temporal inferior and superior retinal artery and vein diameter. CSFP was calculated as 0.44 × body mass index (kg/m(2)) + 0.16 × diastolic blood pressure (mm Hg) - 0.18 × age (years) - 1.91. Larger retinal vein diameters and higher vein-to-artery diameter ratios were significantly associated with higher estimated CSFP (P = 0.001) in multivariable analysis. In contrast, temporal inferior retinal arterial diameter was marginally associated (P = 0.03) with estimated CSFP, and temporal superior artery diameter was not significantly associated (P = 0.10) with estimated CSFP; other microvascular abnormalities, such as arteriovenous crossing signs, were also not significantly associated with estimated CSFP. In a reverse manner, higher estimated CSFP as a dependent variable in the multivariable analysis was associated with wider retinal veins and higher vein-to-artery diameter ratio. In the same model, estimated CSFP was not significantly correlated with retinal artery diameters or other retinal microvascular abnormalities. Correspondingly, arterial hypertension was associated with retinal microvascular abnormalities such as arteriovenous crossing signs (P = 0.003), thinner temporal retinal arteries (P arterial hypertension, an increased retinal vein-to-artery diameter ratio depends on elevated CSFP, which is correlated with blood pressure. © American Journal of Hypertension, Ltd 2014. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

To assess the intimal thickness, flow velocities, and luminal diameter of carotid arteries using high-resolution B-mode ultrasound doppler imaging

Science.gov (United States)

Vemuru, Madhuri; Jabbar, Afzal; Chandra, Suman

2004-04-01

Carotid imaging is a Gold Standard test that provides useful information about the structure and functions of carotid arteries. Spectral imaging helps to evaluate the vessel and hemodynamic changes. High resolution B-mode imaging has emerged as one of the methods of choice for determining the anatomic extent of atherosclerosis and its progression and for assessing cardiovascular risks. The measurements made with Doppler correlate well with pathologic measurements. Recent prospective studies have clearly demonstrated that these measurements of carotid intimal thickness are potent predictors of Myocardial Infarction and Stroke. This method appears very attractive as it is non-invasive, extremely safe, well accepted by the patient and relatively inexpensive. It can be performed serially and has the advantage of visualizing the arterial wall in contrast to angiographic techniques which provide only an outline of the arterial lumen. Recently, there has been an interest in the clinical use of this technique in making difficult clinical decisions like deciding on preventive therapies. 30 subjects aged 21-60 years and 30 subjects aged 61-85 years of both sexes are selected after doing a baseline study to exclude Hypertension, Diabetes, Obesity and Hyperlipidemia. The carotid arteries were examined for intimal thickening, blood flow velocities and luminal diameter. With aging there is a narrowing of the carotid vessels and significant increase in intimal thickening with a consequent increase in the blood flow velocities. Inter-observer, intra-observer and instrument variations are seen and there is no significant change in the values when the distal flow pattern is considered for measurements. Aging produces major cardiovascular changes including decreased elasticity and compliance of great arteries leading to structural and functional alterations in heart and vessels. With aging there is increased intimal thickness and increased pulse wave velocity which is clearly

Claudin5a is required for proper inflation of Kupffer's vesicle lumen and organ laterality.

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Jeong-Gyun Kim

Full Text Available Left-right asymmetric organ development is critical to establish a proper body plan of vertebrates. In zebrafish, the Kupffer's vesicle (KV is a fluid-filled sac which controls asymmetric organ development, and a properly inflated KV lumen by means of fluid influx is a prerequisite for the asymmetric signal transmission. However, little is known about the components that support the paracellular tightness between the KV luminal epithelial cells to sustain hydrostatic pressure during KV lumen expansion. Here, we identified that the claudin5a (cldn5a is highly expressed at the apical surface of KV epithelial cells and tightly seals the KV lumen. Downregulation of cldn5a in zebrafish showed a failure in organ laterality that resulted from malformed KV. In addition, accelerated fluid influx into KV by combined treatment of forskolin and 3-isobutyl-1-methylxanthine failed to expand the partially-formed KV lumen in cldn5a morphants. However, malformed KV lumen and defective heart laterality in cldn5a morphants were significantly rescued by exogenous cldn5a mRNA, suggesting that the tightness between the luminal epithelial cells is important for KV lumen formation. Taken together, these findings suggest that cldn5a is required for KV lumen inflation and left-right asymmetric organ development.

Claudin5a is required for proper inflation of Kupffer's vesicle lumen and organ laterality.

Science.gov (United States)

Kim, Jeong-Gyun; Bae, Sung-Jin; Lee, Hye Shin; Park, Ji-Hyeon; Kim, Kyu-Won

2017-01-01

Left-right asymmetric organ development is critical to establish a proper body plan of vertebrates. In zebrafish, the Kupffer's vesicle (KV) is a fluid-filled sac which controls asymmetric organ development, and a properly inflated KV lumen by means of fluid influx is a prerequisite for the asymmetric signal transmission. However, little is known about the components that support the paracellular tightness between the KV luminal epithelial cells to sustain hydrostatic pressure during KV lumen expansion. Here, we identified that the claudin5a (cldn5a) is highly expressed at the apical surface of KV epithelial cells and tightly seals the KV lumen. Downregulation of cldn5a in zebrafish showed a failure in organ laterality that resulted from malformed KV. In addition, accelerated fluid influx into KV by combined treatment of forskolin and 3-isobutyl-1-methylxanthine failed to expand the partially-formed KV lumen in cldn5a morphants. However, malformed KV lumen and defective heart laterality in cldn5a morphants were significantly rescued by exogenous cldn5a mRNA, suggesting that the tightness between the luminal epithelial cells is important for KV lumen formation. Taken together, these findings suggest that cldn5a is required for KV lumen inflation and left-right asymmetric organ development.

Preparation of lumen-loaded kenaf pulp with magnetite (Fe{sub 3}O{sub 4})

Energy Technology Data Exchange (ETDEWEB)

Zakaria, S.; Ong, B.H.; Ahmad, S.H.; Abdullah, M.; Yamauchi, T

2005-02-15

Magnetic pulps were prepared from unbleached kenaf (hibiscus cannabinus L.) kraft pulps. Fe{sub 3}O{sub 4} or magnetite powder was used to load into the pulp's lumen and pit. Aluminum sulphate [Al{sub 2}(SO{sub 4}){sub 3}] (alum) and polyethylenimine (PEI), both mainly function as retention aid were used throughout the experiment and found to be beneficial in the preparation of this magnetic pulps. The ash content method was used to determine the amount of magnetite retained in the lumen and pit. The utilization of PEI up to 2% per pulp fibres was found to be the best result on lumen loading. The deposition of magnetite powder in lumen and pit is found decrease as the addition of PEI used is more than 2% per pulp fibres. Scanning electron microscope (SEM) clearly shows the distribution of magnetite deposited in the lumen. Tensile index and folding endurance of the loaded fibre decreased slightly as the percentage of loading pigment increased.

Analysis of nuclear reactor pressure vessel flanges

International Nuclear Information System (INIS)

Oliveira, C.A.N. de; Augusto, O.B.

1985-01-01

This work proposes a methodology for the structural analysis of high diameter nuclear reactor pressure vessel flanges. In the analysis the vessel is divided into shell-of-revolution elements, the flanges are represented by rigid rings, and the bolts are treated as beams. The flexibility method is used for solving the problem, and the results are compared with results obtained by the finite element method. (Author) [pt

Long-term lumen depreciation behavior and failure modes of multi-die array LEDs

Science.gov (United States)

Jayawardena, Asiri; Marcus, Daniel; Prugue, Ximena; Narendran, Nadarajah

2013-09-01

One of the main advantages of multi-die array light-emitting diodes (LEDs) is their high flux density. However, a challenge for using such a product in lighting fixture applications is the heat density and the need for thermal management to keep the junction temperatures of all the dies low for long-term reliable performance. Ten multi-die LED array samples for each product from four different manufacturers were subjected to lumen maintenance testing (as described in IES-LM-80-08), and their resulting lumen depreciation and failure modes were studied. The products were tested at the maximum case (or pin) temperature reported by the respective manufacturer by appropriately powering the LEDs. In addition, three samples for each product from two different manufacturers were subjected to rapid thermal cycling, and the resulting lumen depreciation and failure modes were studied. The results showed that the exponential lumen decay model using long-term lumen maintenance data as recommended in IES TM-21 does not fit for all package types. The failure of a string of dies and single die failure in a string were observed in some of the packages.

Comparison of Self-Expanding Polyethylene Terephthalate and Metallic Stents Implanted in Porcine Iliac Arteries

International Nuclear Information System (INIS)

Wilczek, Krzysztof; Scheerder, Ivan de; Wang Kai; Verbeken, Eric; Piessens, Jan

1996-01-01

Purpose: Comparison of the biocompatibility of self-expanding polyethylene terephthalate (PET) stents with self-expanding metallic stents (Wallstents). Methods: Diameter- and length-matched PET stents and Wallstents were symmetrically implanted in the paired iliac arteries of 13 crossbred domestic swine. Stent deployment was studied angiographically and with intravascular ultrasound immediately after stent implantation. The angiographic stented lumen diameter was measured using quantitative vessel analysis before, immediately after stenting, and at 6-week follow-up. Cross-section histopathology and area morphometry were performed. Results: Immediately poststenting, intravascular ultrasound revealed proximal dislocation of 5 of the 13 PET stents, whereas all metal stents were firmly embedded at the implantation site. At 6-week follow-up, three of the remaining PET stents were totally or subtotally occluded by organized thrombus, whereas all metal stents were patent. Compared with immediately poststenting, the angiographic lumen diameter within the five remaining PET stents was reduced by 30%, and that of the metallic stents was virtually unaltered (p < 0.02). This observation was confirmed by postmortem morphometry, wherein the PET-stented vessel segments a diameter stenosis of 40% was measured vs only 9% in the metallic stents (p < 0.0001). Conclusion: PET-stent deployment is difficult to control due to the lack of radiopacity of this stent. PET stents seem to be more thrombogenic and lead to significantly more neointimal proliferation than metallic stents

Improved automated lumen contour detection by novel multifrequency processing algorithm with current intravascular ultrasound system.

Science.gov (United States)

Kume, Teruyoshi; Kim, Byeong-Keuk; Waseda, Katsuhisa; Sathyanarayana, Shashidhar; Li, Wenguang; Teo, Tat-Jin; Yock, Paul G; Fitzgerald, Peter J; Honda, Yasuhiro

2013-02-01

The aim of this study was to evaluate a new fully automated lumen border tracing system based on a novel multifrequency processing algorithm. We developed the multifrequency processing method to enhance arterial lumen detection by exploiting the differential scattering characteristics of blood and arterial tissue. The implementation of the method can be integrated into current intravascular ultrasound (IVUS) hardware. This study was performed in vivo with conventional 40-MHz IVUS catheters (Atlantis SR Pro™, Boston Scientific Corp, Natick, MA) in 43 clinical patients with coronary artery disease. A total of 522 frames were randomly selected, and lumen areas were measured after automatically tracing lumen borders with the new tracing system and a commercially available tracing system (TraceAssist™) referred to as the "conventional tracing system." The data assessed by the two automated systems were compared with the results of manual tracings by experienced IVUS analysts. New automated lumen measurements showed better agreement with manual lumen area tracings compared with those of the conventional tracing system (correlation coefficient: 0.819 vs. 0.509). When compared against manual tracings, the new algorithm also demonstrated improved systematic error (mean difference: 0.13 vs. -1.02 mm(2) ) and random variability (standard deviation of difference: 2.21 vs. 4.02 mm(2) ) compared with the conventional tracing system. This preliminary study showed that the novel fully automated tracing system based on the multifrequency processing algorithm can provide more accurate lumen border detection than current automated tracing systems and thus, offer a more reliable quantitative evaluation of lumen geometry. Copyright © 2011 Wiley Periodicals, Inc.

Measuring the diameter of rising gas bubbles by means of the ultrasound transit time technique

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Richter, T., E-mail: Thomas.Richter6@tu-dresden.de; Eckert, K., E-mail: Kerstin.Eckert@tu-dresden.de; Yang, X.; Odenbach, S.

2015-09-15

Highlights: • Ultrasound transit time technique (UTTT) is applied to the zig-zag raise of gas bubble. • Comparison of bubble diameter and tilt, measured by UTTT, with high-speed imaging. • Uncertainty in the determination of the bubble diameter by UTTT is less than 7%. • UTTT is able to measure dynamic changes in bubble size in opaque liquids and vessels. • UTTT can be applied to liquid metal loops. - Abstract: This study presents ultrasound transit time technique (UTTT) measurements of the diameter variations of single argon bubbles rising in a zig-zag trajectory in water. Simultaneous size measurements with a high-speed camera show that UTTT resolves both the apparent diameter and the tilt of the bubble axis with an accuracy of better than 7%. This qualifies UTTT for the measurement of bubble sizes in opaque liquids, such as liquid metals, or vessels.

Vessel wall and indium-111-labelled platelet response to carotid endarterectomy

International Nuclear Information System (INIS)

Lusby, R.J.; Ferrell, L.D.; Englestad, B.L.; Price, D.C.; Lipton, M.J.; Stoney, R.J.

1983-01-01

Postendarterectomy platelet deposition and thrombus formation may play an important role not only in vessel wall healing but also in the small incidence of postoperative cerebral ischemia and postoperative stenosis. A study has been performed using a canine model to investigate the healing response to carotid endarterectomy and the validity of an in vivo indium-111 (In-111) radiotracer technique in the assessment of postendarterectomy deposition of autologous labelled platelets. Sixteen endarterectomized carotid arteries showed uptake of autologous In-111 platelets immediately after infusion, reaching a maximum by 1 hour with little increase at 24 or 48 hours. No uptake was seen in ten control vessels following platelet infusion (P less than 0.05). At autopsy, seven vessels were demonstrated to have In-111 platelet deposition immediately prior to sacrifice of the animals. Postmortem scanning confirmed the localization to the vessel lumens, and microscopy revealed thrombus formation with or without partial endothelialization. Complete reendothelialization had occurred in the vessels that failed to show platelet deposition. Delayed healing was associated with continuing platelet deposition, excessive thrombus formation, and luminal stenosis. Arteriotomy closure with a vein patch altered the healing characteristics of the vessel with segmental thrombus formation over the vein patch. A preliminary study of the postendarterectomy in vivo In-111 platelet response in humans demonstrated platelet deposition that was not influenced by the administration of antiplatelet drugs at currently prescribed levels

A method to determine the kink resistance of stents and stent delivery systems according to international standards

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Brandt-Wunderlich Christoph

2016-09-01

Full Text Available The kink behavior of vascular stents is of particular interest for clinicians, stent manufacturers and regulatory as a kinked stent generates a lumen loss in the stented vessel and can lead to in-stent restenosis. In this study methods to determine the kink resistance of stents and stent delivery systems according to the ISO 25539-2 and FDA guidance no. 1545 were presented. The methods are applicable for balloon expandable stents as well as for self-expanding stents and determine the lumen loss and residual diameter change dependent on the specific bending radius.

64-slice multidetector coronary CT angiography: in vitro evaluation of 68 different stents

International Nuclear Information System (INIS)

Maintz, David; Seifarth, Harald; Rink, Michael; Oezguen, Murat; Heindel, Walter; Fischbach, Roman; Raupach, Rainer; Flohr, Thomas; Sommer, Torsten

2006-01-01

The purpose of this study was to test a large sample of different coronary artery stents using four image reconstruction approaches with respect to lumen visualization, lumen attenuation, and image noise in 64-slice multidetector-row computed tomography (MDCT) in vitro and to provide a catalogue of currently used coronary artery stents when imaged with state-of the-art MDCT. We examined 68 different coronary artery stents (57 stainless steel, four cobalt-chromium, one cobalt-alloy, two nitinol, four tantalum) in a coronary artery phantom (vessel diameter 3 mm, intravascular attenuation 250 HU, extravascular density -70). Stents were imaged in axial orientation with standard parameters: 32x0.6 collimation, pitch 0.24, 680 mAs, 120 kV, rotation time 0.37 s. Four different image reconstructions were obtained with varying convolution kernels and section thicknesses: (1) soft, 0.6 mm, (2) soft, 0.75, (3) medium soft, 0.6, and (4) stent-optimized sharp, 0.6. To evaluate visualization characteristics of of the stent, the lumen diameter, intraluminal density and noise were measured. The high-resolution kernel offered significantly better average lumen visualization (57% ±10%) and more realistic lumen attenuation (222 HU ±66 HU) at the expense of increased noise (15.3 HU ±3.7 HU) compared with the soft and medium-soft CT angiography (CTA) protocol (p<0.001 for all). Stents with a lumen visibility of more than 66% were: Arthos pico, Driver, Flex, Nexus2, S7, Tenax complete, Vision (all 67%), Symbiot, Teneo (70%), and Radius (73%). Only ten stents showed a lumen visibility of less than 50%. Stent lumen visibility largely varies depending on the stent type. Even with the improved spatial resolution of 64-slice CT, a stent-optimized kernel remains beneficial for stent visualization when compared with the standard medium-soft CTA protocol. Using 64-slice CT and high-resolution kernel, the majority of stent products show a lumen visibility of more than 50% of the stent

Tumor Blood Vessel Dynamics

Science.gov (United States)

Munn, Lance

2009-11-01

``Normalization'' of tumor blood vessels has shown promise to improve the efficacy of chemotherapeutics. In theory, anti-angiogenic drugs targeting endothelial VEGF signaling can improve vessel network structure and function, enhancing the transport of subsequent cytotoxic drugs to cancer cells. In practice, the effects are unpredictable, with varying levels of success. The predominant effects of anti-VEGF therapies are decreased vessel leakiness (hydraulic conductivity), decreased vessel diameters and pruning of the immature vessel network. It is thought that each of these can influence perfusion of the vessel network, inducing flow in regions that were previously sluggish or stagnant. Unfortunately, when anti-VEGF therapies affect vessel structure and function, the changes are dynamic and overlapping in time, and it has been difficult to identify a consistent and predictable normalization ``window'' during which perfusion and subsequent drug delivery is optimal. This is largely due to the non-linearity in the system, and the inability to distinguish the effects of decreased vessel leakiness from those due to network structural changes in clinical trials or animal studies. We have developed a mathematical model to calculate blood flow in complex tumor networks imaged by two-photon microscopy. The model incorporates the necessary and sufficient components for addressing the problem of normalization of tumor vasculature: i) lattice-Boltzmann calculations of the full flow field within the vasculature and within the tissue, ii) diffusion and convection of soluble species such as oxygen or drugs within vessels and the tissue domain, iii) distinct and spatially-resolved vessel hydraulic conductivities and permeabilities for each species, iv) erythrocyte particles advecting in the flow and delivering oxygen with real oxygen release kinetics, v) shear stress-mediated vascular remodeling. This model, guided by multi-parameter intravital imaging of tumor vessel structure

Evaluation of the normal thoracic and abdominal aorta diameters by computerized tomography

International Nuclear Information System (INIS)

Lucarelli, Claudio Luiz

1995-01-01

The study was undertaken to evaluate, through computerized tomography, the diameters of the normal thoracic and abdominal aorta, as well as they are connected to gender, age and body surface area; and the ratio between measurements obtained at the ascending and descending limbs of the thoracic aorta, and between the abdominal aortic diameters. For that reason, we measured the widest anteroposterior diameters of the thoracic aortas at the levels of the arch, the root, the pulmonary artery, and the thoracic-abdominal transition, as well as the level of the emergence of the superior mesenteric artery, of the renal hila and just cephalad to the bifurcation of the abdominal aortas of 350 patients without cardiovascular diseases who had undergone computerized tomography of the thorax and/or abdomen for any other reasons. Observation and statistic analyses led us to conclude that: 1) both the thoracic and abdominal aortic diameters are reduced from their proximal to their distal portions; 2) the body surface influences the size of the aorta, although only extreme variations alter the vessel's caliber; 3) vessel diameter was observed to gradually increase with age; 4) men were found to have larger diameters than age matched women; 5) the ratio between the ascending and descending aortic diameters varies according to gender and age; 6) the relations between abdominal aortic diameters measured at the level of renal hila and cephalad to the bifurcation are independent from gender and age. But the relation between those measured at the level of the superior mesenteric artery and cephalad to the bifurcation are linked to gender, but not to age. (author)

Computed Tomographic Window Setting for Bronchial Measurement to Guide Double-Lumen Tube Size.

Science.gov (United States)

Seo, Jeong-Hwa; Bae, Jinyoung; Paik, Hyesun; Koo, Chang-Hoon; Bahk, Jae-Hyon

2018-04-01

The bronchial diameter measured on computed tomography (CT) can be used to guide double-lumen tube (DLT) sizes objectively. The bronchus is known to be measured most accurately in the so-called bronchial CT window. The authors investigated whether using the bronchial window results in the selection of more appropriately sized DLTs than using the other windows. CT image analysis and prospective randomized study. Tertiary hospital. Adults receiving left-sided DLTs. The authors simulated selection of DLT sizes based on the left bronchial diameters measured in the lung (width 1,500 Hounsfield unit [HU] and level -700 HU), bronchial (1,000 HU and -450 HU), and mediastinal (400 HU and 25 HU) CT windows. Furthermore, patients were randomly assigned to undergo imaging with either the bronchial or mediastinal window to guide DLT sizes. Using the underwater seal technique, the authors assessed whether the DLT was appropriately sized, undersized, or oversized for the patient. On 130 CT images, the bronchial diameter (9.9 ± 1.2 mm v 10.5 ± 1.3 mm v 11.7 ± 1.3 mm) and the selected DLT size were different in the lung, bronchial, and mediastinal windows, respectively (p study, oversized tubes were chosen less frequently in the bronchial window than in the mediastinal window (6/110 v 23/111; risk ratio 0.38; 95% CI 0.19-0.79; p = 0.003). No tubes were undersized after measurements in these two windows. The bronchial measurement in the bronchial window guided more appropriately sized DLTs compared with the lung or mediastinal windows. Copyright © 2017 Elsevier Inc. All rights reserved.

Evolution of regular geometrical shapes in fiber lumens

KAUST Repository

Le, Ngoc Lieu; Kim, Dooli; Nunes, Suzana Pereira

2017-01-01

of the internal channels or lumens of polymeric hollow fibers, leading to polygonal geometries with increasing number of sides. The elasticity of the incipient channel skin and instabilities during fiber formation are affected by the internal coagulant fluid

Analysis of proteome dynamics inside the silk gland lumen of Bombyx mori

Science.gov (United States)

Dong, Zhaoming; Zhao, Ping; Zhang, Yan; Song, Qianru; Zhang, Xiaolu; Guo, Pengchao; Wang, Dandan; Xia, Qingyou

2016-01-01

The silk gland is the only organ where silk proteins are synthesized and secreted in the silkworm, Bombyx mori. Silk proteins are stored in the lumen of the silk gland for around eight days during the fifth instar. Determining their dynamic changes is helpful for clarifying the secretion mechanism of silk proteins. Here, we identified the proteome in the silk gland lumen using liquid chromatography–tandem mass spectrometry, and demonstrated its changes during two key stages. From day 5 of the fifth instar to day 1 of wandering, the abundances of fibroins, sericins, seroins, and proteins of unknown functions increased significantly in different compartments of the silk gland lumen. As a result, these accumulated proteins constituted the major cocoon components. In contrast, the abundances of enzymes and extracellular matrix proteins decreased in the silk gland lumen, suggesting that they were not the structural constituents of silk. Twenty-five enzymes may be involved in the regulation of hormone metabolism for proper silk gland function. In addition, the metabolism of other non-proteinous components such as chitin and pigment were also discussed in this study. PMID:27102218

Problems in manufacturing and transport of pressure vessels of integral reactors

International Nuclear Information System (INIS)

Kralovec, J.

1997-01-01

Integral water-cooled reactors are typical with eliminating large-diameter primary pipes and placing primary components, i.e. steam generators and pressurizers in reactor vessels. This arrangement leads to reactor pressure vessels of large dimensions: diameters, heights and thick walls and subsequently to great weights. Thus, even medium power units have pressure vessels which are on the very limit of present manufacturing capabilities. Principal manufacturing and inspection operations as well as pertinent equipment are concerned: welding, cladding, heat treatment, machining, shop-handling, non-destructive testing, hydraulic pressure tests etc. Tile transport of such a large and heavy component makes a problem which effects its design as well as the selection of the plant site. Railway, road and ship are possible ways of transport each of them having its advantages and limitations. Specific features and limits of the manufacture and transport of large pressure vessels are discussed in the paper. (author)

Endoscopic Retrograde Cholangiopancreatography Using a Dual-Lumen Endogastroscope for Patients with Billroth II Gastrectomy

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Wei Yao

2013-01-01

Full Text Available Objective. To evaluate the safety and efficacy of a dual-lumen forward-viewing endoscope for ERCP in patients with prior Billroth II gastrectomy. Methods. The records of 46 patients treated with ERCP by a dual-lumen forward-viewing endoscope after Billroth II gastrectomy from 2007 to 2012 were reviewed. Results. The success rate of selective cannulation was 82.6% (38/46. Of the 38 cases with successful selective cannulation, endoscopic sphincterotomy was achieved in 23 cases by placing the needle knife through the 2nd lumen, while endoscopic papillary balloon dilatation was conducted in the other 15 cases. Of the 8 failed cases of selective cannulation, 6 had failed afferent loop intubation, and 3 of these 6 patients had Braun’s anastomosis. The safety and efficacy of catheter-assisted endoscopic sphincterotomy were increased by placing the needle knife through the 2nd lumen without altering the conventional endoscopic sphincterotomy procedure. Conclusions. A dual-lumen forward-viewing endoscope can be safely and effectively used to perform ERCP in patients with a Billroth II gastrectomy, except for patients with additional Braun’s anastomosis.

Phenomenological vessel burst investigations

International Nuclear Information System (INIS)

Hippelein, K.W.; Julisch, P.; Muz, J.; Schiedermaier, J.

1985-07-01

Fourteen burst experiments have been carried out using vessels with circumferential and longitudinal flaws, for investigation of the fracture behaviour, i.e. the time-related fracture opening. The vessels had dimensions (outer diameter x wall thickness = 800 x 47 mm) which correspond to the dimensions of the main coolant piping of a 1300 MW e PWR. The test specimens had been made of the base-safe material 20 MnMoNi 55 and of a special, 22 NiMoCr 37 base alloy. The experimental conditions with regard to pressure and temperature have been chosen so as to correspond to normal operating conditions of a PWR (p∝17.5 MPa, T∝300 0 C), i.e. the flaws have been so dimensioned that failure was to be expected at a pressure of p∝17.5 MPa. As a rule, water has been used as the pressure medium, or in some cases air, in order to influence the time-dependent pressure decrease. Fluid and structural dynamics calculations have also been made. In order to determine the impact of a fast propagating crack on the leak-to-fracture curve, which normally is defined by quasistationary experiments, suitable tests have been made with large-volume, cylindrical vessels (outer diameter x wall thickness x length = 3000 x 21 x 14000 mm) made of the material WSt E 43. The leak-before-fracture criterion has been confirmed. (orig./HP) [de

Inner and outer coronary vessel wall segmentation from CCTA using an active contour model with machine learning-based 3D voxel context-aware image force

Science.gov (United States)

Sivalingam, Udhayaraj; Wels, Michael; Rempfler, Markus; Grosskopf, Stefan; Suehling, Michael; Menze, Bjoern H.

2016-03-01

In this paper, we present a fully automated approach to coronary vessel segmentation, which involves calcification or soft plaque delineation in addition to accurate lumen delineation, from 3D Cardiac Computed Tomography Angiography data. Adequately virtualizing the coronary lumen plays a crucial role for simulating blood ow by means of fluid dynamics while additionally identifying the outer vessel wall in the case of arteriosclerosis is a prerequisite for further plaque compartment analysis. Our method is a hybrid approach complementing Active Contour Model-based segmentation with an external image force that relies on a Random Forest Regression model generated off-line. The regression model provides a strong estimate of the distance to the true vessel surface for every surface candidate point taking into account 3D wavelet-encoded contextual image features, which are aligned with the current surface hypothesis. The associated external image force is integrated in the objective function of the active contour model, such that the overall segmentation approach benefits from the advantages associated with snakes and from the ones associated with machine learning-based regression alike. This yields an integrated approach achieving competitive results on a publicly available benchmark data collection (Rotterdam segmentation challenge).

Reducing catheter-related thrombosis using a risk reduction tool centered on catheter to vessel ratio.

Science.gov (United States)

Spencer, Timothy R; Mahoney, Keegan J

2017-11-01

In vascular access practices, the internal vessel size is considered important, and a catheter to vessel ratio (CVR) is recommended to assist clinicians in selecting the most appropriate-sized device for the vessel. In 2016, new practice recommendations stated that the CVR can increase from 33 to 45% of the vessels diameter. There has been evidence on larger diameter catheters and increased thrombosis risk in recent literature, while insufficient information established on what relationship to vessel size is appropriate for any intra-vascular device. Earlier references to clinical standards and guidelines did not clearly address vessel size in relation to the area consumed or external catheter diameter. The aim of this manuscript is to present catheter-related thrombosis evidence and develop a standardized process of ultrasound-guided vessel assessment, integrating CVR, Virchow's triad phenomenon and vessel health and preservation strategies, empowering an evidence-based approach to device placement. Through review, calculation and assessment on the areas of the 33 and 45% rule, a preliminary clinical tool was developed to assist clinicians make cognizant decisions when placing intravascular devices relating to target vessel size, focusing on potential reduction in catheter-related thrombosis. Increasing the understanding and utilization of CVRs will lead to a safer, more consistent approach to device placement, with potential thrombosis reduction strategies. The future of evidence-based data relies on the clinician to capture accurate vessel measurements and device-related outcomes. This will lead to a more dependable data pool, driving the relationship of catheter-related thrombosis and vascular assessment.

Structural features and in-service inspection of the LTHR-200 pressure vessel

International Nuclear Information System (INIS)

Xiong Dunshi; He Shuyan; Liu Junjie; Yu Suyuan

1993-01-01

LTHR-200 is a low temperature district-heating reactor. It adopts double-shell design pressure vessel and metal containment. Because of the safety and structural features of the reactor, the in-service inspection of the pressure vessel can be simplified greatly. LTHR-200 is an integrated arrangement. Both its core components and the main heat exchangers are contained in the reactor pressure vessel. The coolant of the main loop is run by a full-power natural circulation and there need no main pumps and pipes. Thus, the reactor pressure vessel constitutes the pressure boundary of the reactor's main loop coolant. In regard to these features, a small-sized containment is designed for the reactor. The metal safety container with a small volume is placed closely around the reactor pressure vessel. Outside the metal containment, there is a large reinforced concrete construction for the reactor. Their main operation and design parameters are as follows: The pressure vessel: operation pressure = 2.4 MPa; design pressure = 3.0 MPa; design temperature = 250 deg C; 40 year fast neutron (E>1MeV) fluence in the belt-line region = < 10E16n/cm; internal diameter = 5000 mm; material SA516-70; shell thickness 65 mm; The metal containment: maximum operation pressure = 1.8 MPa; design pressure = 1.8 MPa; design temperature = 250 deg. C; upper internal diameter 7000 mm; lower internal diameter = 5600 mm; material = SA516-70; shell thickness, upper part = 80 mm; lower part = 50 mm. All penetrating pipes through the pressure vessel are located at the top penetration section of the shell. All the internal diameters of penetrating pipes are less than 50 mm. Inside and outside the metal containment wall respectively, isolating valves are connected to the reactor coolant pipe which passes through the containment. These two isolating valves use different driving methods. Every penetrating part of the reactor construction uses a proper form of structure according to safety requirements

RELATIONSHIPS BETWEEN ANATOMICAL FEATURES AND INTRA-RING WOOD DENSITY PROFILES IN Gmelina arborea APPLYING X-RAY DENSITOMETRY

Directory of Open Access Journals (Sweden)

Mario Tomazelo-Filho

2007-12-01

Full Text Available Four annual tree-rings (2 of juvenile wood and 2 of mature wood were sampled from fast-growth plantations ofGmelina arborea in two climatic conditions (dry and wet tropical in Costa Rica. Each annual tree-ring was divided in equal parts ina radial direction. For each part, X-ray density as well as vessel percentage, length and width fiber, cell wall thickness and lumendiameter were measured. Wood density and profile patterns of cell dimension demonstrated inconsistency between juvenile andmature wood and climatic conditions. The Pearson correlation matrix showed that intra-ring wood density was positively correlatedwith the cell wall thickness and negatively correlated with vessel percentage, fiber length, lumen diameter and width. The forwardstepwise regressions determined that: (i intra-ring wood density variation could be predicted from 76 to 96% for anatomicalvariation; (ii cell wall thickness was the most important anatomical feature to produce intra-ring wood density variation and (iii thevessel percentage, fiber length, lumen diameter and width were the second most statically significant characteristics to intra-ring wooddensity, however, with low participation of the determination coefficient of stepwise regressions.

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.

Segmentation of the lumen and media-adventitia boundaries of the common carotid artery from 3D ultrasound images

Science.gov (United States)

Ukwatta, E.; Awad, J.; Ward, A. D.; Samarabandu, J.; Krasinski, A.; Parraga, G.; Fenster, A.

2011-03-01

Three-dimensional ultrasound (3D US) vessel wall volume (VWV) measurements provide high measurement sensitivity and reproducibility for the monitoring and assessment of carotid atherosclerosis. In this paper, we describe a semiautomated approach based on the level set method to delineate the media-adventitia and lumen boundaries of the common carotid artery from 3D US images to support the computation of VWV. Due to the presence of plaque and US image artifacts, the carotid arteries are challenging to segment using image information alone. Our segmentation framework combines several image cues with domain knowledge and limited user interaction. Our method was evaluated with respect to manually outlined boundaries on 430 2D US images extracted from 3D US images of 30 patients who have carotid stenosis of 60% or more. The VWV given by our method differed from that given by manual segmentation by 6.7% +/- 5.0%. For the media-adventitia and lumen segmentations, respectively, our method yielded Dice coefficients of 95.2% +/- 1.6%, 94.3% +/- 2.6%, mean absolute distances of 0.3 +/- 0.1 mm, 0.2 +/- 0.1 mm, maximum absolute distances of 0.8 +/- 0.4 mm, 0.6 +/- 0.3 mm, and volume differences of 4.2% +/- 3.1%, 3.4% +/- 2.6%. The realization of a semi-automated segmentation method will accelerate the translation of 3D carotid US to clinical care for the rapid, non-invasive, and economical monitoring of atherosclerotic disease progression and regression during therapy.

Nonvisualization of the gallbladder lumen on sonogram: a sign of acute viral hepatitis

International Nuclear Information System (INIS)

Lim, Jae Hoon; Ko, Young Tae

1986-01-01

Six cases of nonvisulization of the gallbladder lumen in patients with acute viral hepatitis are presented. Follow-up ultrasonographic examinations done during the convalescent period in 2 patients showed normal gallbladders and this was correlated with improvement in enzyme levels. It is suggested that acute viral hepatitis should be considered in the differential diagnosis of nonvisualization of the gallbladder lumen on sonogram.

Nonvisualization of the gallbladder lumen on sonogram: a sign of acute viral hepatitis

Energy Technology Data Exchange (ETDEWEB)

Lim, Jae Hoon; Ko, Young Tae [Kyung Hee University Hospital, Seoul (Korea, Republic of)

1986-04-15

Six cases of nonvisulization of the gallbladder lumen in patients with acute viral hepatitis are presented. Follow-up ultrasonographic examinations done during the convalescent period in 2 patients showed normal gallbladders and this was correlated with improvement in enzyme levels. It is suggested that acute viral hepatitis should be considered in the differential diagnosis of nonvisualization of the gallbladder lumen on sonogram.

Intravascular stenting (IVaS) method for fingertip replantation.

Science.gov (United States)

Narushima, Mitsunaga; Mihara, Makoto; Koshima, Isao; Gonda, Koichi; Takuya, Iida; Kato, Harunosuke; Nakanishi, Kenji; Yamamoto, Yusuke; Araki, Jun; Abe, Hiroaki; Mundinger, Gerhard S; Kikuchi, Kazuki; Uehara, Eri

2009-01-01

Remarkable progress has been made in microsurgery. However, fingertip replantation following amputation has not gained much popularity because of its technical difficulty. We have developed the intravascular stenting (IVaS) method, in which a nylon monofilament is placed inside the vessel lumen to act as a temporary stent, facilitating anastomosis completion. This report describes 7 fingertip replantations using the IVaS method. Intravascular stent size varied from 4-0 to 6-0 (0.199-0.07 mm diameter). There were no cases in which the back wall of a vessel became inadvertently caught in the anastomosis. The overall survival rate for distal digital replants was 85% (6/7 replants). It is very difficult to evenly anastomose vessels of differing diameter, especially on a supermicrosurgical scale. In this respect, the IVaS method plays a role in stably anchoring the 2 vessel ends, allowing for the even spacing of suture knots, even in vessels of different caliber. Because of its ease of use and exactitude, many surgeons may be able to use the IVaS method to reliably complete small anastomoses in fingertip replantations.

Rapid sealing of porcine renal blood vessels, ex vivo, using a high power, 1470-nm laser, and laparoscopic prototype

Science.gov (United States)

Hardy, Luke A.; Hutchens, Thomas C.; Larson, Eric R.; Gonzalez, David A.; Chang, Chun-Hung; Nau, William H.; Fried, Nathaniel M.

2017-05-01

Energy-based, radiofrequency (RF) and ultrasonic (US) devices currently provide rapid sealing of blood vessels during laparoscopic procedures. We are exploring infrared lasers as an alternate energy modality for vessel sealing, capable of generating less collateral thermal damage. Previous studies demonstrated feasibility of sealing vessels in an in vivo porcine model using a 1470-nm laser. However, the initial prototype was designed for testing in open surgery and featured tissue clasping and light delivery mechanisms incompatible with laparoscopic surgery. In this study, a laparoscopic prototype similar to devices currently in surgical use was developed, and performance tests were conducted on porcine renal blood vessels, ex vivo. The 5-mm outer-diameter laparoscopic prototype featured a traditional Maryland jaw configuration that enables tissue manipulation and blunt dissection. Laser energy was delivered through a 550-μm-core-diameter optical fiber with side-delivery from the lower jaw and beam dimensions of 18-mm length×1.2-mm width. The 1470-nm diode laser delivered 68 W with 3-s activation time, consistent with vessel seal times associated with RF and US-based devices. A total of 69 fresh porcine renal vessels with mean diameter of 3.3±1.7 mm were tested, ex vivo. Vessels smaller than 5-mm diameter were consistently sealed (48/51) with burst pressures greater than malignant hypertension blood pressure (180 mmHg), averaging 1038±474 mmHg. Vessels larger than 5 mm were not consistently sealed (6/18), yielding burst pressures of only 174±221 mmHg. Seal width, thermal damage zone, and thermal spread averaged 1.7±0.8, 3.4±0.7, and 1.0±0.4 mm, respectively. Results demonstrated that the 5-mm optical laparoscopic prototype consistently sealed vessels less than 5-mm diameter with low thermal spread. Further in vivo studies are planned to test the performance across a variety of vessels and tissues.

Scoping calculations for design and analysis of large reactor vessels for liquid-metal fast breeder reactor (LMFBR) plants

International Nuclear Information System (INIS)

Fiala, C.; Kulak, R.F.; Ma, D.C.; Pan, Y.C.; Seidensticker, R.W.; Wang, C.Y.; Zeuch, W.R.

1982-01-01

Reactor vessels for commercial-sized LMFBR plants are quite large - ranging 40 to 70 ft in diameter and 50 to 70 ft in overall depth. These stainless steel vessels contain liquid sodium at relatively low pressures, but at high temperatures. The resulting thin-walled vessels present the structural designer and analyst with special problems, particularly in providing a balanced design to accommodate seismic loads, design basis accident loads, and thermal loadings. A comprehensive set of scoping calculations - though preliminary in detail and depth of design - provides substantial guidance to the vessel designer for subsequent design iterations. Emphasis is placed on the analysis of the large-diameter top closure of the vessel - the deck structure

Selective modification of halloysite lumen with octadecylphosphonic acid: new inorganic tubular micelle.

Science.gov (United States)

Yah, Weng On; Takahara, Atsushi; Lvov, Yuri M

2012-01-25

Selective fatty acid hydrophobization of the inner surface of tubule halloysite clay is demonstrated. Aqueous phosphonic acid was found to bind to alumina sites at the tube lumen and did not bind the tube's outer siloxane surface. The bonding was characterized with solid-state nuclear magnetic resonance ((29)Si, (13)C, (31)P NMR), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy. NMR and FTIR spectroscopy of selectively modified tubes proved binding of octadecylphosphonic acid within the halloysite lumen through bidentate and tridentate P-O-Al linkage. Selective modification of the halloysite clay lumen creates an inorganic micelle-like architecture with a hydrophobic aliphatic chain core and a hydrophilic silicate shell. An enhanced capacity for adsorption of the modified halloysite toward hydrophobic derivatives of ferrocene was shown. This demonstrates that the different inner and outer surface chemistry of clay nanotubes can be used for selective modification, enabling different applications from water purification to drug immobilization and controlled release. © 2011 American Chemical Society

Evaluation of Mechanical Properties and Medical Applications of Polycaprolactone Small Diameter Artificial Blood Vessels

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Mahnazsadat Mirbagheri

2017-03-01

Full Text Available Increasing the cardiovascular diseases and decreasing the possibility of autograft surgery are important factors that cause the choice of artificial vascular graft as an alternative treatment method. In this regard, producing artificial grafts similar to natural vessels is an important purpose that has long been followed as a gold standard by many researchers worldwide. In addition, mechanical properties including strength, long patency, bio-compatibility and hydrophobicity are necessary properties to achieve ideal vascular grafts. Hence there are various factors such as polymer type and preparation methods, which contribute to suitable mechanical properties. The electrospinning as an optimized method on one side and biocompatible, degradable and semicrystalline polycaprolactone (PCL on the other side are used for their acceptable mechanical properties to manufacture synthetic vessels. In this study, PCL vascular grafts have been reviewed and a wide range of parameters affecting the improvement of mechanical properties and their performance have been described along with clinical applications. Therefore, by investigating and comparing single and composite PCL vascular grafts, we achieved acceptable results in the field of cell growth and adhesion as well as implanting grafts in animals such as rat and rabbit. By reviewing other studies, it was revealed that synthetic composite vessels made of PCL and natural polymers such as collagen and chitosan and synthetic polymers such as polyurethane (PU for long patency and acceptable cell adhesion have shown good clinical results.

THE ALGORITHM OF DETERMINATION OF EYE FUNDUS VESSELS BLOOD FLOW CHARACTERISTICS ON VIDEOSEQUENCE

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O. V. Nedzvedz

2018-01-01

Full Text Available The method of determination of the dynamic characteristics like the vessel diameter change, the linear and volume blood velocities in the vessels of the eye fundus is considered. Such characteristics allow to determine blood flow changes in the microvasculature affecting the blood flow in the brain, kidneys and coronary vessels. Developed algorithm includes four stages: the video sequence stabilization, the vessels segmentation with the help of a neural network, the determination of the instantaneous velocity in the vessels based on the optical flow and the analysis of the results.

Morphometric analysis of rat femoral vessels under a video magnification system

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Rui Sergio Monteiro de Barros

Full Text Available Abstract The right femoral vessels of 80 rats were identified and dissected. External lengths and diameters of femoral arteries and femoral veins were measured using either a microscope or a video magnification system. Findings were correlated to animals’ weights. Mean length was 14.33 mm for both femoral arteries and femoral veins, mean diameter of arteries was 0.65 mm and diameter of veins was 0.81 mm. In our sample, rats’ body weights were only correlated with the diameter of their femoral veins.

Intracranial arterial aneurysm vasculopathies: targeting the outer vessel wall

International Nuclear Information System (INIS)

Krings, Timo; Piske, Ronie L.; Lasjaunias, Pierre L.

2005-01-01

The pathogenesis of intracranial arterial aneurysms (AA) remains unclear, despite their clinical importance. An improved understanding of this disease is important in choosing therapeutic options. In addition to the ''classical'' berry-type aneurysm, there are various other types of intracranial AA such as infectious, dissecting or giant, partially-thrombosed aneurysms. From the clinician's perspective, the hypothesis that some of these intracranial AA might be due to abluminal factors has been proposed for several years. Indeed, this hypothesis and the empirical use of anti-inflammatory drugs in giant intracranial aneurysms have been confirmed by recent studies reporting that an enzyme involved in the inflammatory cascade (5-lipoxygenase or 5-LO) promotes the pathogenesis of specific aneurysms in humans. 5-LO generates different forms of leukotrienes which are potent mediators of inflammation. Adventitial inflammation leads to a weakening of the media from the abluminal part of the vessel wall due to the release of proinflammatory factors that invade the media, thereby degrading the extracellular matrix, the elastic lamina of the vascular wall, and, finally, the integrity of the vessel lumen. This in turn results in a dilation of the vessel and aneurysm formation. Moreover, neoangiogenesis of vasa vasorum is found in close proximity to 5-LO activated macrophages. In addition to this biological cascade, we argue that repeated subadventitial haemorrhages from the new vasa vasorum play an important role in aneurysm pathogenesis, due to a progressive increase in size mediated by the apposition of new layers of intramural haematoma within the vessel wall. Intracranial giant AA can therefore be regarded as a proliferative disease of the vessel wall induced by extravascular activity. (orig.)

Refinements of the radiographic cadaver injection technique for investigating minute lymphatic vessels.

Science.gov (United States)

Suami, Hiroo; Taylor, G Ian; O'Neill, Jennifer; Pan, Wei-Ren

2007-07-01

The authors previously reported a new technique with which to delineate the lymphatic vessels, using hydrogen peroxide to identify them and a lead oxide suspension to demonstrate them on radiographs. This technique provided excellent studies of the lymph vessels in human cadavers, but there was still room for improvement. Lymph collecting vessels run superficially in some regions, where they may be damaged while the surgeon is attempting to find them. Vessels smaller than 0.3 mm in diameter could not be cannulated with a 30-gauge needle, which was the smallest the authors had available, and the lead oxide suspension often blocked this cannula. The authors also encountered problems holding the cannula steady. The authors solved these problems by using a mixture of hydrogen peroxide and ink to better identify the lymphatics, an extruded glass tube instead of a metal needle to cannulate them, an agate pestle and mortar to grind the lead oxide into finer particles, powdered milk to suspend the lead oxide, and a micromanipulator to facilitate accurate and steady cannulation of the vessels. This study developed these modifications to focus on tributaries of the collecting lymphatic channels that are smaller than 0.3 mm in diameter.

Volumetric analysis demonstrates that true and false lumen remodeling persists for 12 months after thoracic endovascular aortic repair

Directory of Open Access Journals (Sweden)

Ga-Young Suh, PhD

2016-09-01

Full Text Available A 62-year-old man underwent an elephant trunk procedure followed by thoracic endovascular aortic repair (TEVAR. Computed tomography angiography-based models were built to quantify volume of the whole aorta and true and false lumens preoperatively, before TEVAR, after TEVAR, and at follow-up at 3, 6, and 12 months. With TEVAR, descending aortic true lumen volume increased by 54%, then increased additionally by 60% during 12 months. The descending aortic false lumen volume regressed continuously for 12 months following TEVAR, with the most rapid rate from 6 to 12 months at 16 cm3/month. TEVAR immediately increased true lumen volume and continued to remodel the true and false lumens throughout the following 12 months.

Histomorphometric comparative study of blood vessels and their pattern in follicular cyst, odontogenic keratocyst, and ameloblastoma.

Science.gov (United States)

Seifi, Safora; Feizi, Farideh; Khafri, Thoraya; Aram, Mehrdad

2013-03-01

The present study aimed at assessment and histomorphometric analysis of intratumoral and peritumoral (cystic) blood vessels in odontogenic lesions and their pattern on their clinical behavior by immunohistochemistry and morphometry. In a descriptive and analytical cross-sectional study, 45 paraffin blocks of ameloblastoma, odontogenic keratocyst, and follicular cyst were selected and stained immunohistochemically for CD34. In each slide, images of 3 microscopic fields with the highest microvessel density in intratumoral and peritumoral (cystic) areas were captured at 40× magnification with attached camera system. Inner vascular diameter (IVD) and outer vascular diameter (OVD), cross-sectional area (CSA), and the wall thickness (WT) of the vessels were measured with Motic Plus 2 software. The vascular pattern in odontogenic lesions was analyzed. Outer vascular diameter, IVD, and CSA of the vessels in peritumoral (cystic) areas were greater in ameloblastoma than keratocyst (P = 0.001) and follicular cyst (P keratocyst and follicular cyst. Morphometric specifications of blood vessels (IVD, OVD, CSA) and their pattern in peritumoral (cystic) areas may influence the aggressive clinical behavior of ameloblastoma in comparison with keratocyst and follicular cyst.

Neurovascular Network Explorer 1.0: a database of 2-photon single-vessel diameter measurements with MATLAB(®) graphical user interface.

Science.gov (United States)

Sridhar, Vishnu B; Tian, Peifang; Dale, Anders M; Devor, Anna; Saisan, Payam A

2014-01-01

We present a database client software-Neurovascular Network Explorer 1.0 (NNE 1.0)-that uses MATLAB(®) based Graphical User Interface (GUI) for interaction with a database of 2-photon single-vessel diameter measurements from our previous publication (Tian et al., 2010). These data are of particular interest for modeling the hemodynamic response. NNE 1.0 is downloaded by the user and then runs either as a MATLAB script or as a standalone program on a Windows platform. The GUI allows browsing the database according to parameters specified by the user, simple manipulation and visualization of the retrieved records (such as averaging and peak-normalization), and export of the results. Further, we provide NNE 1.0 source code. With this source code, the user can database their own experimental results, given the appropriate data structure and naming conventions, and thus share their data in a user-friendly format with other investigators. NNE 1.0 provides an example of seamless and low-cost solution for sharing of experimental data by a regular size neuroscience laboratory and may serve as a general template, facilitating dissemination of biological results and accelerating data-driven modeling approaches.

Vessel Wall Reaction after Vena Cava Filter Placement

International Nuclear Information System (INIS)

Hoekstra, Arend; Elstrodt, Jan M.; Nikkels, Peter G.J.; Tiebosch, Anton T.M.G.

2002-01-01

Purpose: To evaluate the interaction between the Cordis Keeper vena caval filter and vessel wall in aporcine model.Methods: Implantation of the filter was performed in five pigs. Radiologic data concerning inferior vena cava(IVC) diameter and filter patency, filter leg span, and stability were collected. At 2 or 6 months post-implantation, histopathologic analysis of the IVC wall was performed.Results: All filters remained patent with no evidence of migration. However, at 6 months follow-up, two legs of one filter penetrated the vessel wall and were adherent to the liver. These preliminary results suggest that with the observed gradual increase in the filter span, the risk of caval wall penetration increases with time, especially in a relatively small IVC(average diameter 16 mm).Conclusion: The Cordis Keeper filter was well tolerated, but seems to be prone to caval wall penetration in the long term

Extravasal occlusion of large vessels with titanic clips: efficiency, indications, and contraindications.

Science.gov (United States)

Vasilenko, Yu V; Kim, A I; Kotov, S A

2002-11-01

The mechanism of extravasal occlusion of blood vessels with titanic clips "Atrauclip" and "Ligaclip extra" was studied in order to reveal indications and contraindications to their use. Occlusion with the clips of both types was ineffective in vessels with a diameter of >7.0 mm. Arteritis or the presence of an intravascular occlusion facility in the vessel were also the contraindications for clip occlusion. In overcases the procedure of occlusion with titanic clips was efficient and atraumatic.

Intravital two-photon microscopy of immune cell dynamics in corneal lymphatic vessels.

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Philipp Steven

Full Text Available BACKGROUND: The role of lymphatic vessels in tissue and organ transplantation as well as in tumor growth and metastasis has drawn great attention in recent years. METHODOLOGY/PRINCIPAL FINDINGS: We now developed a novel method using non-invasive two-photon microscopy to simultaneously visualize and track specifically stained lymphatic vessels and autofluorescent adjacent tissues such as collagen fibrils, blood vessels and immune cells in the mouse model of corneal neovascularization in vivo. The mouse cornea serves as an ideal tissue for this technique due to its easy accessibility and its inducible and modifiable state of pathological hem- and lymphvascularization. Neovascularization was induced by suture placement in corneas of Balb/C mice. Two weeks after treatment, lymphatic vessels were stained intravital by intrastromal injection of a fluorescently labeled LYVE-1 antibody and the corneas were evaluated in vivo by two-photon microscopy (TPM. Intravital TPM was performed at 710 nm and 826 nm excitation wavelengths to detect immunofluorescence and tissue autofluorescence using a custom made animal holder. Corneas were then harvested, fixed and analyzed by histology. Time lapse imaging demonstrated the first in vivo evidence of immune cell migration into lymphatic vessels and luminal transport of individual cells. Cells immigrated within 1-5.5 min into the vessel lumen. Mean velocities of intrastromal corneal immune cells were around 9 µm/min and therefore comparable to those of T-cells and macrophages in other mucosal surfaces. CONCLUSIONS: To our knowledge we here demonstrate for the first time the intravital real-time transmigration of immune cells into lymphatic vessels. Overall this study demonstrates the valuable use of intravital autofluorescence two-photon microscopy in the model of suture-induced corneal vascularizations to study interactions of immune and subsequently tumor cells with lymphatic vessels under close as possible

Analysis of three ex-vessel loss-of-coolant accidents in the first wall cooling system of NET/ITER

International Nuclear Information System (INIS)

Komen, E.M.J.; Koning, H.

1993-01-01

An ex-vessel LOCA may be caused by a rupture of a cooling pipe located outside the vacuum vessel. No plasma shutdown and no other counteractions have been assumed in order to study the worst case conditions of the accidents. The next three ex-vessel LOCAs in the primary cooling system of the first wall have been analysed: 1. a large break ex-vessel LOCA caused by a rupture of the cold leg (inner diameter 0.314 m) of the main circuit; 2. an intermediate break ex-vessel LOCA caused by a rupture of a sector inlet feeder (inner diameter 0.158 m); 3. an intermediate break ex-vessel LOCA caused by a rupture of the surge line (inner diameter 0.180 m) of the pressurizer. The analyses have been performed using the thermal-hydraulic system analysis code RELAP5/MOD3. In the first two scenarios, melting in the first wall starts about 90 s after break initiation. In the third scenario, melting in the first wall start about 323 s after break initiation. Special emphasis has been paid to the characteristics of the break flows, the transient thermal-hydraulic behaviour of the cooling system, and the temperature development in the first wall. (orig.)

Low molecular weight dextran provides similar optical coherence tomography coronary imaging compared to radiographic contrast media.

Science.gov (United States)

Frick, Kyle; Michael, Tesfaldet T; Alomar, Mohammed; Mohammed, Atif; Rangan, Bavana V; Abdullah, Shuaib; Grodin, Jerrold; Hastings, Jeffrey L; Banerjee, Subhash; Brilakis, Emmanouil S

2014-11-01

Optical coherence tomography (OCT) coronary imaging requires displacement of red blood cells from the vessel lumen. This is usually accomplished using radiographic contrast. Low molecular weight dextran has low cost and is safe in low volumes. In the present study, we compared dextran with contrast for coronary OCT imaging. Fifty-one vessels in 26 patients were sequentially imaged using manual injection of radiographic contrast (iodixanol) and dextran. OCT images were analyzed at 1 mm intervals to determine the image clarity (defined as a visible lumen border > 270°) and to measure the lumen area and lumen diameter. To correct for the refractive index of dextran, the dextran area measurements were multiplied by 1.117 and the dextran length measurements were multiplied by 1.057. A total of 3,418 cross-sections (1,709 with contrast and 1,709 with dextran) were analyzed. There were no complications related to OCT imaging or to contrast or dextran administration. Clear image segments were observed in 97.0% vs. 96.7% of the cross-sections obtained with contrast and dextran, respectively (P = 0.45). The mean lumen areas were also similar: 6.69 ± 1.95 mm(2) with iodixanol vs. 7.06 ± 2.06 mm(2) with dextran (correlation coefficient 0.984). The image quality and measurements during OCT image acquisition are similar for dextran and contrast. Dextran could be used instead of contrast for OCT imaging, especially in patients in whom contrast load minimization is desired. © 2013 Wiley Periodicals, Inc.

A new evaluation of the upper esophageal sphincter using the functional lumen imaging probe: a preliminary report.

LENUS (Irish Health Repository)

Regan, J

2012-03-06

Objective and reliable evaluation of upper esophageal sphincter (UES) opening during swallowing based on videofluoroscopy and pharyngeal manometry challenges dysphagia clinicians. The functional lumen imaging probe (FLIP) is a portable tool based on impedance planimetry originally designed to measure esophogastric junction compliance. It is hypothesized that FLIP can evaluate UES distensibility, and can provide UES diameter and pressure measurements at rest, during swallowing, and during voluntary maneuvers. Eleven healthy adult subjects consented to FLIP evaluation. The probe was inserted transorally, and the balloon was positioned across the UES. Two 20-mL ramp distensions were completed. Changes in UES diameter and intraballoon pressure were measured during dry and 5-mL liquid swallows, and during voluntary swallow postures and maneuvers employed in clinical practice. The protocol was completed by 10 of 11 healthy subjects. Mean intraballoon pressure increased throughout 5-mL (5.8 mmHg; -4.5-18.6 mmHg), 10-mL (8.7 mmHg; 2.3-28.5 mmHg), 15-mL (17.3 mmHg; 9.5-34.8 mmHg), and 20-mL (31.2 mmHg; 16-46.3 mmHg) balloon volumes. Mean resting UES diameter (4.9 mm) increased during dry swallows (9.2 mm) and 5-mL liquid swallows (7.7 mm). Mean UES diameter increased during 5-mL liquid swallows with head turn to right (8.1 mm) and left (8.3 mm), chin tuck (8.4 mm), effortful swallow (8.5 mm), Mendelsohn maneuver (8.1 mm), and supraglottic swallow (7.8 mm). FLIP was safely inserted and distended in the UES, and provided useful quantitative data regarding UES distensibility and UES diameter changes during swallowing maneuvers. Further research is being conducted to explore the role of FLIP in UES evaluation.

Healthy Lung Vessel Morphology Derived From Thoracic Computed Tomography

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Michael Pienn

2018-04-01

Full Text Available Knowledge of the lung vessel morphology in healthy subjects is necessary to improve our understanding about the functional network of the lung and to recognize pathologic deviations beyond the normal inter-subject variation. Established values of normal lung morphology have been derived from necropsy material of only very few subjects. In order to determine morphologic readouts from a large number of healthy subjects, computed tomography pulmonary angiography (CTPA datasets, negative for pulmonary embolism, and other thoracic pathologies, were analyzed using a fully-automatic, in-house developed artery/vein separation algorithm. The number, volume, and tortuosity of the vessels in a diameter range between 2 and 10 mm were determined. Visual inspection of all datasets was used to exclude subjects with poor image quality or inadequate artery/vein separation from the analysis. Validation of the algorithm was performed manually by a radiologist on randomly selected subjects. In 123 subjects (men/women: 55/68, aged 59 ± 17 years, the median overlap between visual inspection and fully-automatic segmentation was 94.6% (69.2–99.9%. The median number of vessel segments in the ranges of 8–10, 6–8, 4–6, and 2–4 mm diameter was 9, 34, 134, and 797, respectively. Number of vessel segments divided by the subject's lung volume was 206 vessels/L with arteries and veins contributing almost equally. In women this vessel density was about 15% higher than in men. Median arterial and venous volumes were 1.52 and 1.54% of the lung volume, respectively. Tortuosity was best described with the sum-of-angles metric and was 142.1 rad/m (138.3–144.5 rad/m. In conclusion, our fully-automatic artery/vein separation algorithm provided reliable measures of pulmonary arteries and veins with respect to age and gender. There was a large variation between subjects in all readouts. No relevant dependence on age, gender, or vessel type was observed. These data may

In-vessel coolability and steam explosion in Nordic BWRs

International Nuclear Information System (INIS)

Ma, W.; Hansson, R.; Li, L.; Kudinov, P.; Cadinu, F.; Tran, C-.T.

2010-05-01

The INCOSE project is to reduce the uncertainty in quantification of steam explosion risk and in-vessel coolability in Nordic BWR plants with the cavity flooding as a severe accident management (SAM) measure. During 2009 substantial advances and new insights into physical mechanisms were gained for studies of: (i) in-vessel corium coolability - development of the methodologies to assess the efficiency of the control rod guide tube (CRGT) cooling as a potential SAM measure; (ii) debris bed coolability - characterization of the effective particle diameter of multi-size particles and qualification of friction law for two-phase flow in the beds packed with multi-size particles; and (iii) steam explosion - investigation of the effect of binary oxides mixtures properties on steam explosion. An approach for coupling of ECM/PECM models with RELAP5 was developed to enhance predictive fidelity for melt pool heat transfer. MELCOR was employed to examine the CRGT cooling efficiency by considering an entire accident scenario, and the simulation results show that the nominal flowrate (∼10kg/s) of CRGT cooling is sufficient to maintain the integrity of the vessel in a BWR of 3900 MWth, if the water injection is activated no later than 1 hour after scram. The POMECO-FL experimental data suggest that for a particulate bed packed with multi-size particles, the effective particle diameter can be represented by the area mean diameter of the particles, while at high velocity (Re>7) the effective particle diameter is closer to the length mean diameter. The pressure drop of two-phase flow through the particulate bed can be predicted by Reed's model. The steam explosion experiments performed at high melt superheat (>200oC) using oxidic mixture of WO3-CaO didn't detect an apparent difference in steam explosion energetics and preconditioning between the eutectic and noneutectic melts. This points out that the next step of MISTEE experiment will be conducted at lower superheat. (author)

A basic study on the ITER tritium storage vessel design and components

International Nuclear Information System (INIS)

Chung, H. S.; Ahn, D. H.; Kim, K. R.; Yim, S. P.; Paek, S. W.; Lee, M. S.; Lee, S. H.; Shim, M. H.

2006-01-01

The ZrCo getter beds are built of a primary vessel which contains the ZrCo powder mixed with Cu spheres of less than one mm diameter and of a secondary outer vessel. The purpose of the secondary outer vessel is to capture permeated or leaked tritium and to present a good thermal insulation when properly evacuated. A third volume, a helium filled loop, is installed in the primary volume to remove the decay heat and is used to perform tritium accountancy measurements

Confinement Vessel Assay System: Calibration and Certification 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; Gomez, Cipriano [Retired CMR-OPS: OPERATIONS; Mayo, Douglas R. [Los Alamos National Laboratory; 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

2012-07-17

Los Alamos National Laboratory has a number of spherical confinement vessels (CVs) 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. The Confinement Vessel Assay System (CVAS) was developed to measure the amount of SNM in CVs before and after cleanout. Prior to cleanout, the system will be used to perform a verification measurement of each vessel. After cleanout, the system will be used to perform safeguards-quality assays of {le} 100-g {sup 239}Pu equivalent in a vessel for safeguards termination. The system was calibrated in three different mass regions (low, medium, and high) to cover the entire plutonium mass range that will be assayed. The low mass calibration and medium mass calibration were verified for material positioned in the center of an empty vessel. The systematic uncertainty due to position bias was estimated using an MCNPX model to simulate the response of the system to material localized at various points along the inner surface of the vessel. The background component due to cosmic ray spallation was determined by performing measurements of an empty vessel and comparing to measurements in the same location with no vessel present. The CVAS has been tested and calibrated in preparation for verification and safeguards measurements of CVs before and after cleanout.

Confinement Vessel Assay System: Calibration and Certification Report

International Nuclear Information System (INIS)

Frame, Katherine C.; Bourne, Mark M.; Crooks, William J.; Evans, Louise; Gomez, Cipriano; Mayo, Douglas R.; Miko, David K.; Salazar, William R.; Stange, Sy; Vigil, Georgiana M.

2012-01-01

Los Alamos National Laboratory has a number of spherical confinement vessels (CVs) 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. The Confinement Vessel Assay System (CVAS) was developed to measure the amount of SNM in CVs before and after cleanout. Prior to cleanout, the system will be used to perform a verification measurement of each vessel. After cleanout, the system will be used to perform safeguards-quality assays of (le) 100-g 239 Pu equivalent in a vessel for safeguards termination. The system was calibrated in three different mass regions (low, medium, and high) to cover the entire plutonium mass range that will be assayed. The low mass calibration and medium mass calibration were verified for material positioned in the center of an empty vessel. The systematic uncertainty due to position bias was estimated using an MCNPX model to simulate the response of the system to material localized at various points along the inner surface of the vessel. The background component due to cosmic ray spallation was determined by performing measurements of an empty vessel and comparing to measurements in the same location with no vessel present. The CVAS has been tested and calibrated in preparation for verification and safeguards measurements of CVs before and after cleanout.

Ex-vessel boiling experiments: laboratory- and reactor-scale testing of the flooded cavity concept for in-vessel core retention. Pt. II. Reactor-scale boiling experiments of the flooded cavity concept for in-vessel core retention

International Nuclear Information System (INIS)

Chu, T.Y.; Bentz, J.H.; Slezak, S.E.; Pasedag, W.F.

1997-01-01

For pt.I see ibid., p.77-88 (1997). This paper summarizes the results of a reactor-scale ex-vessel boiling experiment for assessing the flooded cavity design of the heavy water new production reactor. The simulated reactor vessel has a cylindrical diameter of 3.7 m and a torispherical bottom head. Boiling outside the reactor vessel was found to be subcooled nucleate boiling. The subcooling mainly results from the gravity head, which in turn results from flooding the side of the reactor vessel. The boiling process exhibits a cyclic pattern with four distinct phases: direct liquid-solid contact, bubble nucleation and growth, coalescence, and vapor mass dispersion. The results show that, under prototypic heat load and heat flux distributions, the flooded cavity will be effective for in-vessel core retention in the heavy water new production reactor. The results also demonstrate that the heat dissipation requirement for in-vessel core retention, for the central region of the lower head of an AP-600 advanced light water reactor, can be met with the flooded cavity design. (orig.)

Characterization of swallow modulation in response to bolus volume in healthy subjects accounting for catheter diameter.

Science.gov (United States)

Ferris, Lara; Schar, Mistyka; McCall, Lisa; Doeltgen, Sebastian; Scholten, Ingrid; Rommel, Nathalie; Cock, Charles; Omari, Taher

2018-06-01

Characterization of the pharyngeal swallow response to volume challenges is important for swallowing function assessment. The diameter of the pressure-impedance recording catheter may influence these results. In this study, we captured key physiological swallow measures in response to bolus volume utilizing recordings acquired by two catheters of different diameter. Ten healthy adults underwent repeat investigations with 8- and 10-Fr catheters. Liquid bolus swallows of volumes 2.5, 5, 10, 20, and 30 mL were recorded. Measures indicative of distension, contractility, and flow timing were assessed. Pressure-impedance recordings with pressure-flow analysis were used to capture key distension, contractility, and pressure-flow timing parameters. Larger bolus volumes increased upper esophageal sphincter distension diameter (P < .001) and distension pressures within the hypopharynx and upper esophageal sphincter (P < .05). Bolus flow timing measures were longer, particularly latency of bolus propulsion ahead of the pharyngeal stripping wave (P < .001). Use of a larger-diameter catheter produced higher occlusive pressures, namely upper esophageal sphincter basal pressure (P < .005) and upper esophageal sphincter postdeglutitive pressure peak (P < .001). The bolus volume swallowed changed measurements indicative of distension pressure, luminal diameter, and pressure-flow timing; this is physiologically consistent with swallow modulation to accommodate larger, faster-flowing boluses. Additionally, catheter diameter predominantly affects lumen occlusive pressures. Appropriate physiological interpretation of the pressure-impedance recordings of pharyngeal swallowing requires consideration of the effects of volume and catheter diameter. NA. Laryngoscope, 128:1328-1334, 2018. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Neutrophil-Mediated Delivery of Therapeutic Nanoparticles across Blood Vessel Barrier for Treatment of Inflammation and Infection.

Science.gov (United States)

Chu, Dafeng; Gao, Jin; Wang, Zhenjia

2015-12-22

Endothelial cells form a monolayer in lumen of blood vessels presenting a great barrier for delivery of therapeutic nanoparticles (NPs) into extravascular tissues where most diseases occur, such as inflammation disorders and infection. Here, we report a strategy for delivering therapeutic NPs across this blood vessel barrier by nanoparticle in situ hitchhiking activated neutrophils. Using intravital microscopy of TNF-α-induced inflammation of mouse cremaster venules and a mouse model of acute lung inflammation, we demonstrated that intravenously (iv) infused NPs made from denatured bovine serum albumin (BSA) were specifically internalized by activated neutrophils, and subsequently, the neutrophils containing NPs migrated across blood vessels into inflammatory tissues. When neutrophils were depleted using anti-Gr-1 in a mouse, the transport of albumin NPs across blood vessel walls was robustly abolished. Furthermore, it was found that albumin nanoparticle internalization did not affect neutrophil mobility and functions. Administration of drug-loaded albumin NPs markedly mitigated the lung inflammation induced by LPS (lipopolysaccharide) or infection by Pseudomonas aeruginosa. These results demonstrate the use of an albumin nanoparticle platform for in situ targeting of activated neutrophils for delivery of therapeutics across the blood vessel barriers into diseased sites. This study demonstrates our ability to hijack neutrophils to deliver nanoparticles to targeted diseased sites.

Elephant trunk in a small-calibre true lumen for chronic aortic dissection: cause of haemolytic anaemia?

Science.gov (United States)

Araki, Haruna; Kitamura, Tadashi; Horai, Tetsuya; Shibata, Ko; Miyaji, Kagami

2014-12-01

The elephant trunk technique for aortic dissection is useful for reducing false lumen pressure; however, a folded vascular prosthesis inside the aorta can cause haemolysis. The purpose of this study was to investigate whether an elephant trunk in a small-calibre lumen can cause haemolysis. Inpatient and outpatient records were retrospectively reviewed. Two cases of haemolytic anaemia after aortic surgery using the elephant trunk technique were identified from 2011 to 2013. A 64-year-old man, who underwent graft replacement of the ascending aorta for acute Stanford type A aortic dissection, presented with enlargement of the chronic dissection of the descending aorta and moderate aortic regurgitation. A two-stage surgery was scheduled. Total arch replacement with an elephant trunk in the true lumen and concomitant aortic valve replacement were performed. Postoperatively, he developed severe haemolytic anaemia because of the folded elephant trunk. The anaemia improved after the second surgery, including graft replacement of the descending aorta. Similarly, a 61-year-old man, who underwent total arch replacement for acute Stanford type A aortic dissection, presented with enlargement of the chronic dissection of the descending aorta. Graft replacement of the descending aorta with an elephant trunk inserted into the true lumen was performed. The patient postoperatively developed haemolytic anaemia because of the folded elephant trunk, which improved after additional stent grafting into the elephant trunk. A folded elephant trunk in a small-calibre lumen can cause haemolysis. Therefore, inserting an elephant trunk in a small-calibre true lumen during surgery for chronic aortic dissection should be avoided. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Vessel wall reaction after vena cava filter placement

NARCIS (Netherlands)

Hoekstra, A; Elstrodt, JM; Nikkels, PGJ; Tiebosch, ATMG

2002-01-01

Purpose: To evaluate the interaction between the Cordis Keeper vena caval filter and vessel wall in a porcine model. Methods: Implantation of the filter was performed in five pigs. Radiologic data concerning inferior vena cava (IVC) diameter and filter patency, filter leg span, and stability were

Management of colon stents based on Bernoulli's principle.

Science.gov (United States)

Uno, Yoshiharu

2017-03-01

The colonic self-expanding metal stent (SEMS) has been widely used for "bridge to surgery" and palliative therapy. However, if the spread of SEMS is insufficient, not only can a decompression effect not be obtained but also perforation and obstructive colitis can occur. The mechanism of occurrence of obstructive colitis and perforation was investigated by flow dynamics. Bernoulli's principle was applied, assuming that the cause of inflammation and perforation represented the pressure difference in the proximal lumen and stent. The variables considered were proximal lumen diameter, stent lumen diameter, flow rate into the proximal lumen, and fluid density. To model the right colon, the proximal lumen diameter was set at 50 mm. To model the left-side colon, the proximal lumen diameter was set at 30 mm. For both the right colon model and the left-side colon model, the difference in pressure between the proximal lumen and the stent was less than 20 mmHg, when the diameter of the stent lumen was 14 mm or more. Both the right colon model and the left-side colon model were 30 mmHg or more at 200 mL s -1 when the stent lumen was 10 mm or less. Even with an inflow rate of 90-110 mL s -1 , the pressure was 140 mmHg when the stent lumen diameter was 5 mm. In theory, in order to maintain the effectiveness of SEMS, it is necessary to keep the diameter of the stent lumen at 14 mm or more.

Computational Fluid Dynamics Analysis of Pulsatile Blood Flow Behavior in Modelled Stenosed Vessels with Different Severities

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Mohsen Mehrabi

2012-01-01

Full Text Available This study focuses on the behavior of blood flow in the stenosed vessels. Blood is modelled as an incompressible non-Newtonian fluid which is based on the power law viscosity model. A numerical technique based on the finite difference method is developed to simulate the blood flow taking into account the transient periodic behaviour of the blood flow in cardiac cycles. Also, pulsatile blood flow in the stenosed vessel is based on the Womersley model, and fluid flow in the lumen region is governed by the continuity equation and the Navier-Stokes equations. In this study, the stenosis shape is cosine by using Tu and Devil model. Comparing the results obtained from three stenosed vessels with 30%, 50%, and 75% area severity, we find that higher percent-area severity of stenosis leads to higher extrapressure jumps and higher blood speeds around the stenosis site. Also, we observe that the size of the stenosis in stenosed vessels does influence the blood flow. A little change on the cross-sectional value makes vast change on the blood flow rate. This simulation helps the people working in the field of physiological fluid dynamics as well as the medical practitioners.

Ezetimibe Promotes Brush Border Membrane-to-Lumen Cholesterol Efflux in the Small Intestine.

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Takanari Nakano

Full Text Available Ezetimibe inhibits Niemann-Pick C1-like 1 (NPC1L1, an apical membrane cholesterol transporter of enterocytes, thereby reduces intestinal cholesterol absorption. This treatment also increases extrahepatic reverse cholesterol transport via an undefined mechanism. To explore this, we employed a trans-intestinal cholesterol efflux (TICE assay, which directly detects circulation-to-intestinal lumen 3H-cholesterol transit in a cannulated jejunal segment, and found an increase of TICE by 45%. To examine whether such increase in efflux occurs at the intestinal brush border membrane(BBM-level, we performed luminal perfusion assays, similar to TICE but the jejunal wall was labelled with orally-given 3H-cholesterol, and determined elevated BBM-to-lumen cholesterol efflux by 3.5-fold with ezetimibe. Such increased efflux probably promotes circulation-to-lumen cholesterol transit eventually; thus increases TICE. Next, we wondered how inhibition of NPC1L1, an influx transporter, resulted in increased efflux. When we traced orally-given 3H-cholesterol in mice, we found that lumen-to-BBM 3H-cholesterol transit was rapid and less sensitive to ezetimibe treatment. Comparison of the efflux and fractional cholesterol absorption revealed an inverse correlation, indicating the efflux as an opposite-regulatory factor for cholesterol absorption efficiency and counteracting to the naturally-occurring rapid cholesterol influx to the BBM. These suggest that the ezetimibe-stimulated increased efflux is crucial in reducing cholesterol absorption. Ezetimibe-induced increase in cholesterol efflux was approximately 2.5-fold greater in mice having endogenous ATP-binding cassette G5/G8 heterodimer, the major sterol efflux transporter of enterocytes, than the knockout counterparts, suggesting that the heterodimer confers additional rapid BBM-to-lumen cholesterol efflux in response to NPC1L1 inhibition. The observed framework for intestinal cholesterol fluxes may provide ways to

Nuclear reactor construction with bottom supported reactor vessel

International Nuclear Information System (INIS)

Sharbaugh, J.E.

1987-01-01

This patent describes an improved liquid metal nuclear reactor construction comprising: (a) a nuclear reactor core having a bottom platform support structure; (b) a reactor vessel for holding a large pool of low pressure liquid metal coolant and housing the core; (c) a containment structure surrounding the reactor vessel and having a sidewall spaced outwardly from the reactor vessel side wall and having a base mat spaced below the reactor vessel bottom end wall; (d) a central small diameter post anchored to the containment structure base mat and extending upwardly to the reactor vessel to axially fix the bottom end wall of the reactor vessel and provide a center column support for the lower end of the reactor core; (e) annular support structure disposed in the reactor vessel on the bottom end wall and extending about the lower end of the core; (f) structural support means disposed between the containment structure base mat and bottom end of the reactor vessel wall and cooperating for supporting the reactor vessel at its bottom end wall on the containment structure base mat 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; (g) a bed of insulating material 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; freely expand radially from the central post as it heats up while providing continuous support thereof; (h) a deck supported upon the wall of the containment vessel above the top open end of the reactor vessel; and (i) extendible and retractable coupling means extending between the deck and the top open end of the reactor vessel and flexibly and sealably interconnecting the reactor vessel at its top end to the deck

Microbes vs. chemistry in the origin of the anaerobic gut lumen.

Science.gov (United States)

Friedman, Elliot S; Bittinger, Kyle; Esipova, Tatiana V; Hou, Likai; Chau, Lillian; Jiang, Jack; Mesaros, Clementina; Lund, Peder J; Liang, Xue; FitzGerald, Garret A; Goulian, Mark; Lee, Daeyeon; Garcia, Benjamin A; Blair, Ian A; Vinogradov, Sergei A; Wu, Gary D

2018-04-17

The succession from aerobic and facultative anaerobic bacteria to obligate anaerobes in the infant gut along with the differences between the compositions of the mucosally adherent vs. luminal microbiota suggests that the gut microbes consume oxygen, which diffuses into the lumen from the intestinal tissue, maintaining the lumen in a deeply anaerobic state. Remarkably, measurements of luminal oxygen levels show nearly identical pO 2 (partial pressure of oxygen) profiles in conventional and germ-free mice, pointing to the existence of oxygen consumption mechanisms other than microbial respiration. In vitro experiments confirmed that the luminal contents of germ-free mice are able to chemically consume oxygen (e.g., via lipid oxidation reactions), although at rates significantly lower than those observed in the case of conventionally housed mice. For conventional mice, we also show that the taxonomic composition of the gut microbiota adherent to the gut mucosa and in the lumen throughout the length of the gut correlates with oxygen levels. At the same time, an increase in the biomass of the gut microbiota provides an explanation for the reduction of luminal oxygen in the distal vs. proximal gut. These results demonstrate how oxygen from the mammalian host is used by the gut microbiota, while both the microbes and the oxidative chemical reactions regulate luminal oxygen levels, shaping the composition of the microbial community throughout different regions of the gut.

Fast retinal vessel detection and measurement using wavelets and edge location refinement.

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Peter Bankhead

Full Text Available The relationship between changes in retinal vessel morphology and the onset and progression of diseases such as diabetes, hypertension and retinopathy of prematurity (ROP has been the subject of several large scale clinical studies. However, the difficulty of quantifying changes in retinal vessels in a sufficiently fast, accurate and repeatable manner has restricted the application of the insights gleaned from these studies to clinical practice. This paper presents a novel algorithm for the efficient detection and measurement of retinal vessels, which is general enough that it can be applied to both low and high resolution fundus photographs and fluorescein angiograms upon the adjustment of only a few intuitive parameters. Firstly, we describe the simple vessel segmentation strategy, formulated in the language of wavelets, that is used for fast vessel detection. When validated using a publicly available database of retinal images, this segmentation achieves a true positive rate of 70.27%, false positive rate of 2.83%, and accuracy score of 0.9371. Vessel edges are then more precisely localised using image profiles computed perpendicularly across a spline fit of each detected vessel centreline, so that both local and global changes in vessel diameter can be readily quantified. Using a second image database, we show that the diameters output by our algorithm display good agreement with the manual measurements made by three independent observers. We conclude that the improved speed and generality offered by our algorithm are achieved without sacrificing accuracy. The algorithm is implemented in MATLAB along with a graphical user interface, and we have made the source code freely available.

Vacuum vessels for the LHC magnets arrive at CERN

CERN Multimedia

2001-01-01

The first batch of pre-series vacuum vessels for the LHC dipole magnets has just been delivered to CERN. The vessels are components of the cryostats and will provide the thermal insulation for the superconducting magnets. The first batch of vacuum vessels for the LHC dipole magnets with the team taking part at CERN in ordering and installing them. Left to right : Claude Hauviller, Monique Dupont, Lloyd Williams, Franck Gavin, Alain Jacob, Christophe Vuitton, Davide Bozzini, Laure Sandri, Mikael Sjoholm and André de Saever. In 2006 all that will be seen of the LHC superconducting dipoles in the LHC tunnel will be a line of over 1230 blue cylindrical vacuum vessels. Ten vessels, each weighing 4 tonnes, are already at CERN. On 6 July the first batch of pre-series vessels reached the Lab-oratory from the firm SIMIC Spa whose works are near Savona in north-western Italy. Despite appearances, these 15-metre long, 1-metre diameter blue tubes are much more sophisticated than sections of a run-of-the-mill...

Drug-eluting stents appear superior to bare metal stents for vein-graft PCI in vessels up to a stent diameter of 4 mm

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Oliver P. Guttmann

2016-05-01

Full Text Available BackgroundResearch trials have shown improved short-term outcome with drug-eluting stents (DES over bare metal stents (BMS in saphenous vein graft (SVG percutaneous coronary intervention (PCI, primarily by reducing target vessel revascularization (TVR for in-stent restenosis. We compared the outcomes in patients undergoing SVG stent implantation treated with DES or BMS. In exploratory analyses we investigated the influence of stent generation and diameter.MethodsData were obtained from a prospective database of 657 patients who underwent PCI for SVG lesions between 2003 and 2011. A total of 344 patients had PCI with BMS and 313 with DES. Propensity scores were developed based on 15 observed baseline covariates in a logistic regression model with stent type as the dependent variable. The nearest-neighbour-matching algorithm with Greedy 5-1 Digit Matching was used to produce two patient cohorts of 313 patients each. We assessed major adverse cardiac events (MACE out to a median of 3.3 years (interquartile range: 2.1-4.1. MACE was defined as all-cause mortality, myocardial infarction (MI, TVR and stroke.ResultsThere was a significant difference in MACE between the two groups in favour of DES (17.9% DES vs. 31.2% BMS group; p = 0.0017 over the 5-year follow-up period. MACE was driven by increased TVR in the BMS group. There was no difference in death, MI or stroke. Adjusted Cox analysis confirmed a decreased risk of MACE for DES compared with BMS 0.75 (95% confidence interval (CI 0.52-0.94, with no difference in the hazard of all-cause mortality (hazard ratio: 1.08; 95% CI: 0.77-1.68. However, when looking at stent diameters greater than 4 mm, no difference was seen in MACE rates between BMS and DES.ConclusionsOverall in our cohort of patients who had PCI for SVG disease, DES use resulted in lower MACE rates compared with BMS over a 5-year follow-up period; however, for stent diameters over 4 mm no difference in MACE rates was seen.

Heavy wall pressure vessels for energy systems

International Nuclear Information System (INIS)

Canonico, D.A.

Modifications of steels currently accepted in the Code appear to provide improved mechanical properties. These steels may permit the fabrication of larger diameter vessels with thinner section sizes and improved reliability and integrity. Adapting current specifications should expedite Code approval. Finally the challenge of improving welding procedures and adapting processes for field applications will result in higher quality weldments

Fluoroscopic guidance for placing a double lumen endotracheal tube in adults.

Science.gov (United States)

Calenda, Emile; Baste, Jean Marc; Hajjej, Ridha; Rezig, Najiba; Moriceau, Jerome; Diallo, Yaya; Sghaeir, Slim; Danielou, Eric; Peillon, Christophe

2014-09-01

The aim of this study was to assess the right placement of the double lumen endotracheal tube with fluoroscopic guidance, which is used in first intention prior to the fiberscope in our institution. This was a prospective observational study. The study was conducted in vascular and thoracic operating rooms. We enrolled 205 patients scheduled for thoracic surgery, with ASA physical statuses of I (n = 37), II (n = 84), III (n = 80), and IV (n = 4). Thoracic procedures were biopsy (n = 20), wedge (n = 34), culminectomy (n = 6), lobectomy (n = 82), pneumonectomy (n = 4), sympathectomy (n = 9), symphysis (n = 47), and thymectomy (n = 3). The intubation with a double lumen tube was performed with the help of a laryngoscope. Tracheal and bronchial balloons were inflated and auscultation was performed after right and left exclusions. One shot was performed to locate the position of the bronchial tube and the hook. Fluoroscopic guidance was used to relocate the tube in case of a wrong position. When the fluoroscopic guidance failed to position the tube, a fiberscope was used. Perioperative collapse of the lung was assessed by the surgeon during the surgery. Correct fluoroscopic image was obtained after the first attempt in 58.5% of patients therefore a misplaced position was encountered in 41.5%. The fluoroscopic guidance allowed an exact repositioning in 99.5% of cases, and the mean duration of the procedure was 8 minutes. A fiberscope was required to move the hook for one patient. We did not notice a moving of the double lumen endotracheal tube during the surgery. The surgeon satisfaction was 100%. The fluoroscopy evidenced the right position of the double lumen tube and allowed a right repositioning in 99.5% of patients with a very simple implementation. Copyright © 2014. Published by Elsevier B.V.

Multimodal quantitation of the effects of endovascular therapy for vasospasm on cerebral blood flow, transcranial doppler ultrasonographic velocities, and cerebral artery diameters.

Science.gov (United States)

Oskouian, Rod J; Martin, Neil A; Lee, Jae Hong; Glenn, Thomas C; Guthrie, Donald; Gonzalez, Nestor R; Afari, Arash; Viñuela, Fernando

2002-07-01

The goal of this study was to quantify the effects of endovascular therapy on vasospastic cerebral vessels. We reviewed the medical records for 387 patients with ruptured intracranial aneurysms who were treated at a single institution (University of California, Los Angeles) between May 1, 1993, and March 31, 2001. Patients who developed cerebral vasospasm and underwent cerebral arteriographic, transcranial Doppler ultrasonographic, and cerebral blood flow (CBF) studies before and after endovascular therapy for cerebral arterial spasm (vasospasm) were included in this study. Forty-five patients fulfilled the aforementioned criteria and were treated with either papaverine infusion, papaverine infusion with angioplasty, or angioplasty alone. After balloon angioplasty (12 patients), CBF increased from 27.8 +/- 2.8 ml/100 g/min to 28.4 +/- 3.0 ml/100 g/min (P = 0.87); the middle cerebral artery blood flow velocity was 1 57.6 +/- 9.4 cm/s and decreased to 76.3 +/- 9.3 cm/s (P < 0.05), with a mean increase in cerebral artery diameters of 24.4%. Papaverine infusion (20 patients) transiently increased the CBF from 27.5 +/- 2.1 ml/100 g/min to 38.7 +/- 2.8 ml/100 g/min (P < 0.05) and decreased the middle cerebral artery blood flow velocity from 109.9 +/- 9.1 cm/s to 82.8 +/- 8.6 cm/s (P < 0.05). There was a mean increase in vessel diameters of 30.1% after papaverine infusion. Combined treatment (13 patients) significantly increased the CBF from 33.3 +/- 3.2 ml/100 g/min to 41.7 +/- 2.8 ml/100 g/min (P< 0.05) and decreased the transcranial Doppler velocities from 148.9 +/- 12.7 cm/s to 111.4 +/- 10.6 cm/s (P < 0.05), with a mean increase in vessel diameters of 42.2%. Balloon angioplasty increased proximal vessel diameters, whereas papaverine treatment effectively dilated distal cerebral vessels. In our small series, we observed no correlation between early clinical improvement or clinical outcomes and any of our quantitative or physiological data (CBF, transcranial Doppler

Small-Diameter PTFE Portosystemic Shunts: Portocaval vs Mesocaval

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Robert Shields

1998-01-01

Full Text Available Fifty-seven patients with failed sclerotherapy received a mesocaval interposition shunt with an externally supported, ringed polytetrafluoroethylene prosthesis of either 10 or 12 mm diameter. Thirty-one patients had Child-Pugh gradeA disease and 26 grade B; all had a liver volume of 1000– 2500 ml. Follow-up ranged from 16 months to 6 years 3 months. Three patients (5 per cent died in the postoperative period. There were two postoperative recurrences of variceal haemorrhage and one recurrent bleed in the second year after surgery. The cumulative shunt patency rate was 95 per cent and the incidence of encephalopathy 9 per cent; the latter was successfully managed by protein restriction and/or lactulose therapy. The actuarial survival rate for the whole group at 6 years was 78 per cent, for those with Child-Pugh grade A 88 per cent and for grade B 67 per cent. Small-lumen mesocaval interposition shunting achieves portal decompression, preserves hepatopetal flow, has a low incidence of shunt thrombosis, prevents recurrent variceal bleeding and is not associated with significant postoperative encephalopathy.

Changes in wood density, wood anatomy and hydraulic properties of the xylem along the root-to-shoot flow path in tropical rainforest trees.

Science.gov (United States)

Schuldt, Bernhard; Leuschner, Christoph; Brock, Nicolai; Horna, Viviana

2013-02-01

It is generally assumed that the largest vessels are occurring in the roots and that vessel diameters and the related hydraulic conductance in the xylem are decreasing acropetally from roots to leaves. With this study in five tree species of a perhumid tropical rainforest in Sulawesi (Indonesia), we searched for patterns in hydraulic architecture and axial conductivity along the flow path from small-diameter roots through strong roots and the trunk to distal sun-canopy twigs. Wood density differed by not more than 10% across the different flow path positions in a species, and branch and stem wood density were closely related in three of the five species. Other than wood density, the wood anatomical and xylem hydraulic traits varied in dependence on the position along the flow path, but were unrelated to wood density within a tree. In contrast to reports from conifers and certain dicotyledonous species, we found a hump-shaped variation in vessel diameter and sapwood area--specific conductivity along the flow path in all five species with a maximum in the trunk and strong roots and minima in both small roots and twigs; the vessel size depended on the diameter of the organ. This pattern might be an adaptation to the perhumid climate with a low risk of hydraulic failure. Despite a similar mean vessel diameter in small roots and twigs, the two distal organs, hydraulically weighted mean vessel diameters were on average 30% larger in small roots, resulting in ∼ 85% higher empirical and theoretical specific conductivities. Relative vessel lumen area in percent of sapwood area decreased linearly by 70% from roots to twigs, reflecting the increase in sclerenchymatic tissue and tracheids in acropetal direction in the xylem. Vessel size was more closely related to the organ diameter than to the distance along the root-to-shoot flow path. We conclude that (i) the five co-occurring tree species show convergent patterns in their hydraulic architecture despite different growth

Variation in the wood anatomical structure of Gmelina arborea (Verbenaceae trees at different ecological conditions in Costa Rica

Directory of Open Access Journals (Sweden)

Róger Moya

2008-06-01

Full Text Available The tree Gmelina arborea has been widely introduced in Costa Rica for commercial purposes. This new conditions for melina cause variations on anatomy in secondary xylem of the trees growing in plantations. The objective of the present research was to determine the variation in the anatomy of xylem caused by the ecological conduction variation. Dimensions of fiber, axial parenchyma percentage of cross sections, parameters of vessels and the ray were measured. The results showed that some anatomical characteristics remained stable despite variations of ecological conditions, especially radial parenchyma and anatomical features which were less affected by the altitude. On the other hand, the vessels, axial parenchyma and fiber were less stable because they were affected significantly by the longitude, latitude, altitude and precipitation. Latitude significantly affected vessel percentage, length and diameter of the fiber and lumen. Longitude affected vessel percentage and fiber diameter. Altitude had a significant correlation with the amount of cells at ray height. Annual average precipitation affected vessel percentage and diameter, not only of the fiber, but also of the lumen. These results suggest that the new growth conditions of G. arborea trees in Costa Rica have produced an anatomic adaptation. Rev. Biol. Trop. 56 (2: 689-704. Epub 2008 June 30.Gmelina arborea ha sido introducida y ampliamente sembrada en Costa Rica en plantaciones de rápido crecimiento. Estas nuevas condiciones ecológicas provocan variación en la anatomía del xilema de estos árboles. El presente trabajo tuvo como objetivo determinar la variación en la anatomía del xilema debido a la variación de la latitud, longitud, altitud y precipitación. Se evaluaron las dimensiones de las fibras, el porcentaje de área ocupada por el parénquima y los parámetros de los vasos y los radios. Algunas características anatómicas se mantuvieron estables con las variaciones de las

The behaviour of the pulmonary vessels on X-ray films of children with asthma bronchiale

International Nuclear Information System (INIS)

Hegenbarth, R.; Toeroek, M.; Medizinische Hochschule Hannover

1986-01-01

On X-ray films of 51 children with asthma bronchiale the authors determined the vascular diameter of the right ascending pulmonary artery, the right vein of the upper lobe, and the peripheral vessels in the upper and lower pulmonary fields at an exactly defined distance from the hilus point, and compared these data with those of a control group of 143 healthy children. During the asthma attack the width of the right descending pulmonary artery and of the vein of the upper lobe corresponded to the values of the control group, whereas the vascular diameters in the upper and lower fields were clearly narrowed. Moreover, in most of the asthmatic children the authors found arc-shaped vessels and irregularly occluded vessels in the periphery of the lungs. (orig.) [de

Multiple Coronary Chamber Microfistulas or Persistent Thebesian Vessels?

Directory of Open Access Journals (Sweden)

Cernica Daniel

2017-09-01

Full Text Available Coronary fistulas are rare, not gender-specific congenital conditions, consisting of communications between the coronary arteries and either another coronary vessel or a cardiac chamber. In contrast to large fistulas, small fistulas, named “minimae cordis veneae” or the Thebesius venous system, are draining into heart chambers and form a vascular network in the cardiac lumen. In this article, we present the case of a 72-year-old female with a significant history of cardiovascular disease, admitted to our clinic because of rest dyspnea, fatigue, and minimal chest pain. The 12-lead electrocardiogram showed a trifascicular block (a second-degree atrioventricular block Mobitz II, associated with a right bundle branch block and left anterior fascicle block and negative T waves in DII, DIII, aVF, V4–V6 leads. An invasive coronary angiography was performed, which revealed no significant atherosclerotic lesions. However, a persistent capillary blush was present at the apex site of the left ventricular chamber, draining from the distal segments of both the anterior descending coronary artery and the posterior interventricular coronary artery. The intramural vascular network generating a left ventricle angiogram image of this kind was suggestive for persistent Thebesian vessels connecting the two coronaries with the left ventricular chamber.

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.

Proof testing of an explosion containment vessel

Energy Technology Data Exchange (ETDEWEB)

Esparza, E.D. [Esparza (Edward D.), San Antonio, TX (United States); Stacy, H.; Wackerle, J. [Los Alamos National Lab., NM (United States)

1996-10-01

A steel containment vessel was fabricated and proof tested for use by the Los Alamos National Laboratory at their M-9 facility. The HY-100 steel vessel was designed to provide total containment for high explosives tests up to 22 lb (10 kg) of TNT equivalent. The vessel was fabricated from an 11.5-ft diameter cylindrical shell, 1.5 in thick, and 2:1 elliptical ends, 2 in thick. Prior to delivery and acceptance, three types of tests were required for proof testing the vessel: a hydrostatic pressure test, air leak tests, and two full design charge explosion tests. The hydrostatic pressure test provided an initial static check on the capacity of the vessel and functioning of the strain instrumentation. The pneumatic air leak tests were performed before, in between, and after the explosion tests. After three smaller preliminary charge tests, the full design charge weight explosion tests demonstrated that no yielding occurred in the vessel at its rated capacity. The blast pressures generated by the explosions and the dynamic response of the vessel were measured and recorded with 33 strain channels, 4 blast pressure channels, 2 gas pressure channels, and 3 displacement channels. This paper presents an overview of the test program, a short summary of the methodology used to predict the design blast loads, a brief description of the transducer locations and measurement systems, some of the hydrostatic test strain and stress results, examples of the explosion pressure and dynamic strain data, and some comparisons of the measured data with the design loads and stresses on the vessel.

Comparison of different ligature materials used for T-tube esophageal exclusion.

Science.gov (United States)

Lee, Y C; Luh, S P; Tsai, C C; Hsu, H C; Chu, S H

1992-03-01

Four different ligature materials--plain catgut, chromic catgut, dexon and silk--were used for ligature of the distal arm during T-tube exclusion of the cervical esophagus in 12 dogs. Ligature by plain catgut was maintained for only a short period, but the duration of esophageal occlusion with the other three ligature materials was around 10 days. Ligated esophageal segments were examined grossly and histologically two months after the procedure. The diameter of the esophageal lumen in the ligated segments had become smaller compared with the neighboring normal esophageal lumen. The most prominent histologic changes were atrophy and fibrosis of the muscle coat, vessel congestion and inflammatory cell infiltration in the ligated segments. These tissue reactions were more severe in the chromic catgut and silk ligatures. Among the 11 evaluable dogs, four had symptoms of dysphagia after removal of the T-tube. All four dogs had a sinus discharge and granuloma formation at the T-tube esophagostoma. The diameter of the esophageal lumen was more constricted in dogs with dysphagia. Among the four ligature materials, dexon had the advantages of a long duration of occlusion, less tissue fibrosis and little sequel of esophageal stenosis, making it the most suitable for ligature during esophageal exclusion.

Enteroclysis in adult celiac disease: assessment of jejuno-ileal diameter and of number of folds

International Nuclear Information System (INIS)

La Seta, F.; Bucellato, A.; Cabibbo, L.; Cottone, M.; Salerno, G.; Dardanoni, G.

1991-01-01

The authors retrospectively reviewed the radiographic findings (obtained with double-contrast small bowel enema) of 27 patients with adult celiac disease and of 27 healthy control subjects. Two parameters were measurated in two different locations; lumen diameter and number of folds both in proximal jejunum and in the distal ileum. Statistical differences in mean values between cases and controls were calculated, and correlations between the four variables were assessed. Sensitivity, specificity and their 95% confidence limits were calculated for all the variables. The best parameter in discriminating cases from controls seems to be the caliber of distal ileum (>3 cm), with 93% sensitivity and 100% specificity. The value of the obtained results is discussed

Depiction of blood vessels by x-ray phase contrast

Energy Technology Data Exchange (ETDEWEB)

Momose, Atsushi [School of Engineering, University of Tokyo, Tokyo (Japan); Takeda, Tohoru; Itai, Yuji [Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Ibaraki (Japan)

2001-04-01

Blood vessels in livers of a mouse and a rat were depicted by phase-contrast x-ray imaging with an x-ray interferometer without using contrast agents. X-ray interference patterns were converted to image mapping x-ray phase shift caused by the livers using the technique of phase-shifting x-ray interferometry. The arteries and veins to and from the livers were tied before excision in order to prevent blood from flowing out of the liver. The x-ray phase shift caused by blood was substantially different from that caused by other soft sues, and consequently trees of blood vessels were revealed in the images. Vessels of diameter smaller than 0.1 mm were detected. This result suggests new possibilities for investigating vascular systems. (author)

Bioresorbable vascular scaffolds for LMCA with double vessel disease under IVUS guidance

Directory of Open Access Journals (Sweden)

Sridhar Kasturi, MD, DM, FACC

2015-12-01

Full Text Available An 80-year-old male patient, presented with chest pain. ECG showed ST elevation in leads V2 to V4 and T wave inversion in leads V2-V6. Check angiogram revealed ostial LMCA 70% lesion & mid-LAD 90% lesion and LCX proximal 80% lesion. Predilatation of LMCA lesion was done with 2.0 × 12 mm NC Trek balloon and the LAD lesion with 2.0 × 12 mm and 2.5 × 08 mm (NC Trek balloons. Prestenting IVUS (Intravascular ultrasound was done with Atlantis SR pro 40 MHz 3.6Fr catheter. IVUS showed the LAD to have a minimal lumen area of 2.6 sq mm with 90% fibrotic plaque and a vessel size of 2.5 mm and the LMCA to have a minimal lumen area of 8.8 sq mm with 70% fibrotic plaque and vessel size of 3.8 mm. Mid-LAD stenting was done with 2.5 × 28 mm Absorb Stent (BVS. Predilatation of LCX lesion was done with 2.5 × 08 mm NC Trek balloon. Then stenting was performed with 3.0 × 28 mm Absorb Stent (BVS. Check angiogram showed edge dissection proximal to the BVS Stent which was covered with 3.0 × 12 mm Xience Xpedtion Stent (DES. Then LMCA Stenting was done with 3.5 × 12 mm Absorb Stent. Post dilatation was done with 4.0 × 08 mm NC Trek balloon. Post Stenting LMCA - LAD IVUS was done. LMCA and LAD Stents were well opposed without any dissection or residual stenosis. TIMI III Flow was achieved in the final results.

An 810 ft/sec soil impact test of a 2-foot diameter model nuclear reactor containment system

Science.gov (United States)

Puthoff, R. L.

1972-01-01

A soil impact test was conducted on a 880-pound 2-foot diameter sphere model. The impact area consisted of back filled desert earth and rock. The impact generated a crater 5 feet in diameter by 5 feet deep. It buried itself a total of 15 feet - as measured to the bottom of the model. After impact the containment vessel was pressure checked. No leaks were detected nor cracks observed.

Investigation of vessel visibility of iterative reconstruction method in coronary computed tomography angiography using simulated vessel phantom

International Nuclear Information System (INIS)

Inoue, Takeshi; Uto, Fumiaki; Ichikawa, Katsuhiro; Hara, Takanori; Urikura, Atsushi; Hoshino, Takashi; Miura, Youhei; Terakawa, Syouichi

2012-01-01

Iterative reconstruction methods can reduce the noise of computed tomography (CT) images, which are expected to contribute to the reduction of patient dose CT examinations. The purpose of this study was to investigate impact of an iterative reconstruction method (iDose 4 , Philips Healthcare) on vessel visibility in coronary CT angiography (CTA) by using phantom studies. A simulated phantom was scanned by a CT system (iCT, Philips Healthcare), and the axial images were reconstructed by filtered back projection (FBP) and given a level of 1 to 7 (L1-L7) of the iterative reconstruction (IR). The vessel visibility was evaluated by a quantitative analysis using profiles across a 1.5-mm diameter simulated vessel as well as visual evaluation for multi planar reformation (MPR) images and volume rendering (VR) images in terms of the normalized-rank method with analysis of variance. The peak CT value of the profiles decreased with IR level and full width at half maximum of the profile also decreased with the IR level. For normalized-rank method, there was no statistical difference between FBP and L1 (20% dose reduction) for both MPR and VR images. The IR levels higher than L1 sacrificed the spatial resolution for the 1.5-mm simulated vessel, and their visual vessel visibilities were significantly inferior to that of the FBP. (author)

Confinement Vessel Assay System: Design and Implementation Report

International Nuclear Information System (INIS)

Frame, Katherine C.; Bourne, Mark M.; Crooks, William J.; Evans, Louise; Mayo, Douglas R.; Gomez, Cipriano D.; Miko, David K.; Salazar, William R.; Stange, Sy; Vigil, Georgiana M.

2012-01-01

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 and 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 252 Cf placed a various locations throughout the measurement system. Measurements were also performed with a 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.

Dynamic CT in dissecting aortic aneurysm

International Nuclear Information System (INIS)

Fujita, Nobuyuki; Matsuoka, Yosuke; Mizuo, Hideyo; Shirato, Hiroki; Irie, Goro

1985-01-01

especially about the branching of major vessels Eight cases of aortic dissection were analysed to evaluate detectability of the branching of major vessels from a ture or false lumen, by dynamic CT. Although recognition of the branching is easy when the direct continuity to a dissected lumen is demonstrated, but without visualization of direct continuity or with no information about dissected lumens, it is sometimes difficult or leads us to misdiagnosis. The diagnostic accuracy is 100% when direct continuity to a dissected lumen is demonstrated, or dynamic CT revealed branching pattern distinctly. Dynamic CT is useful for a diagnosis of dissecting aneurysm and branching pattern of major vessels. (author)

Dual energy CTA of the supraaortic arteries: Technical improvements with a novel dual source CT system

Energy Technology Data Exchange (ETDEWEB)

Lell, Michael M., E-mail: Michael.lell@uk-erlangen.de [Department of Radiology, University Erlangen, Maximiliansplatz 1, 91054 Erlangen (Germany); Hinkmann, Fabian [Department of Radiology, University Erlangen, Maximiliansplatz 1, 91054 Erlangen (Germany); Nkenke, Emeka [Department of Maxillofacial Surgery, University Erlangen (Germany); Schmidt, Bernhard [Bayer-Schering Healthcare, Berlin (Germany); Seidensticker, Peter [Siemens Healthcare, CT-Division, Forchheim (Germany); Kalender, Willi A. [Institute of Medical Physics, University Erlangen (Germany); Uder, Michael [Department of Radiology, University Erlangen, Maximiliansplatz 1, 91054 Erlangen (Germany); Achenbach, Stephan [Department of Cardiology, University Erlangen (Germany)

2010-11-15

Objectives: Computed tomography angiography (CTA) is a well-accepted imaging modality to evaluate the supraaortic vessels. Initial reports have suggested that dual energy CTA (DE-CTA) can enhance diagnosis by creating bone-free data sets, which can be visualized in 3D, but a number of limitations of this technique have also been addressed. We sought to describe the performance of DE-CTA of the supraaortic vessels with a novel dual source CT system with special emphasis on image quality and post-processing related artifacts. Materials and methods: Thirty-three patients underwent carotid CT angiography on a second generation dual source CT system. Simultaneous acquisitions of 100 and 140 kV data sets in arterial phase were performed. Two examiners evaluated overall bone suppression with a 3-point scale (1 = poor; 3 = excellent) and image quality regarding integrity of the vessel lumen of different vessel segments (n = 26) with a 5-point scale (1 = poor; 5 = excellent), CTA source data served as the reference. Results: Excellent bone suppression could be achieved in the head and neck. Only minor bone remnants occurred, mean score for bone removal was 2.9. Mean score for vessel integrity was 4.3. Eight hundred fifty-seven vessel segments could be evaluated. Six hundred thirty-five segments (74%) showed no lumen alteration, 65 segments (7.6%) lumen alterations <10%, 27 segments (3.1%) lumen alterations >10% resulting in a total luminal reduction <50%, 17 segments (2%) lumen alterations of more than 10% resulting in a total luminal reduction >50%, and 113 segments (13.2%) showed a gap in the vessel course (100% total lumen reduction). Artificial gaps of the vessel lumen occurred in 28 vessel segments due to artifacts caused by dental hardware and in all but one (65) ophthalmic arteries. Conclusions: Excellent bone suppression could be achieved, DE imaging with 100 and 140 kV lead to improved image quality and vessel integrity in the shoulder region than previously

A 2D driven 3D vessel segmentation algorithm for 3D digital subtraction angiography data

International Nuclear Information System (INIS)

Spiegel, M; Hornegger, J; Redel, T; Struffert, T; Doerfler, A

2011-01-01

Cerebrovascular disease is among the leading causes of death in western industrial nations. 3D rotational angiography delivers indispensable information on vessel morphology and pathology. Physicians make use of this to analyze vessel geometry in detail, i.e. vessel diameters, location and size of aneurysms, to come up with a clinical decision. 3D segmentation is a crucial step in this pipeline. Although a lot of different methods are available nowadays, all of them lack a method to validate the results for the individual patient. Therefore, we propose a novel 2D digital subtraction angiography (DSA)-driven 3D vessel segmentation and validation framework. 2D DSA projections are clinically considered as gold standard when it comes to measurements of vessel diameter or the neck size of aneurysms. An ellipsoid vessel model is applied to deliver the initial 3D segmentation. To assess the accuracy of the 3D vessel segmentation, its forward projections are iteratively overlaid with the corresponding 2D DSA projections. Local vessel discrepancies are modeled by a global 2D/3D optimization function to adjust the 3D vessel segmentation toward the 2D vessel contours. Our framework has been evaluated on phantom data as well as on ten patient datasets. Three 2D DSA projections from varying viewing angles have been used for each dataset. The novel 2D driven 3D vessel segmentation approach shows superior results against state-of-the-art segmentations like region growing, i.e. an improvement of 7.2% points in precision and 5.8% points for the Dice coefficient. This method opens up future clinical applications requiring the greatest vessel accuracy, e.g. computational fluid dynamic modeling.

New aspects of MRI for diagnostics of large vessel vasculitis and primary angiitis of the central nervous system

International Nuclear Information System (INIS)

Saam, T.; Habs, M.; Cyran, C.C.; Grimm, J.; Reiser, M.F.; Nikolaou, K.; Pfefferkorn, T.; Schueller, U.

2010-01-01

Vasculitis is a rare disease and clinical symptoms are often unspecific. Accurate and early diagnosis is mandatory in order to prevent complications, such as loss of vision or stroke. Imaging techniques can contribute to establishing a definite diagnosis and to evaluate disease activity and the extent of the disease in various vascular regions. Conventional imaging methods, such as computed tomography (CT) and magnetic resonance (MR) angiography, as well as digital subtraction angiography allow the vessel lumen but not the vessel wall to be depicted. However, vasculitis is a disease which primarily affects the vessel wall, therefore conventional imaging modalities often fail to make a definite diagnosis. Recently black-blood high resolution MR in vivo imaging has been used to visualize cervical and intracranial vasculitis. This review article presents imaging protocols for intracranial and cervical black-blood MR imaging and clinical cases with large vessel vasculitis and vasculitis of the central nervous system. Furthermore the current literature, examples of the most common differential diagnoses of cervical and cranial arteriopathy and the potential of other imaging modalities, such as PET/CT and ultrasound will be discussed. (orig.) [de

Decellularized ovine arteries as small-diameter vascular grafts

International Nuclear Information System (INIS)

Mancuso, L; Cao, G; Gualerzi, A; Boschetti, F; Loy, F

2014-01-01

Atherosclerosis and its complications still represent the leading cause of death in the developed countries. While autologous blood vessels may be regarded as the best solution for peripheral and coronary bypass, they are unavailable in most patients. Even though tissue engineering techniques are often applied to the development of small-diameter vascular grafts, limiting factors of this approach are represented by the lack of essential extracellular matrix proteins and/or poor biomechanical properties of the scaffolds used. Along these lines, the aim of this study was to develop a decellularization protocol for ovine carotids to be used as suitable small-diameter vascular grafts. Samples were treated either with sodium dodecyl sulphate (SDS) or with Trypsin and Triton X-100; a final nuclease digestion was performed for both protocols. Morphological analyses demonstrate complete removal of nuclei and cellular components in treated vessels, also confirmed by significant reduction in wall thickness and DNA content. Essential extracellular matrix proteins such as collagen, elastin, and fibronectin are well preserved after decellularization. From a mechanical point of view, Trypsin and Triton X-100 treated arteries show elastic modules and compliance comparable to native carotids, whereas the use of SDS makes samples stiffer, with a significant decrease in the compliance mean value and an increase in longitudinal and circumferential Young’s modules. It is demonstrated that the treatment where Trypsin and Triton X-100 are combined guarantees complete decellularization of carotids, with no significant alteration of biomechanical and structural properties, thus preserving a suitable environment for adhesion, proliferation, and migration of cells. (paper)

Pressure vessels for reactors made from structural steel with limited tensile strength

International Nuclear Information System (INIS)

Machatti, H.

1973-01-01

The reactor pressure vessel is prestressed in several directions with prestressing elements fabricated of steel with a high yielding point. This design allows a substantial reduction of wall thickness or an increase of the inner diameter at equal wall thickness. The prestress of the prestressing elements is designed to achieve a maximum stress release of the vessel walls at normal operating conditions and to fully utilize the maximum load of the vessel walls. For safety reasons the cross section of the prestressing elements is constructed in a way that strain is always 20 % lower the yield point. (P.K.)

Automated registration of multispectral MR vessel wall images of the carotid artery

Energy Technology Data Exchange (ETDEWEB)

Klooster, R. van ' t; Staring, M.; Reiber, J. H. C.; Lelieveldt, B. P. F.; Geest, R. J. van der, E-mail: rvdgeest@lumc.nl [Department of Radiology, Division of Image Processing, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Klein, S. [Department of Radiology and Department of Medical Informatics, Biomedical Imaging Group Rotterdam, Erasmus MC, Rotterdam 3015 GE (Netherlands); Kwee, R. M.; Kooi, M. E. [Department of Radiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht 6202 AZ (Netherlands)

2013-12-15

Purpose: Atherosclerosis is the primary cause of heart disease and stroke. The detailed assessment of atherosclerosis of the carotid artery requires high resolution imaging of the vessel wall using multiple MR sequences with different contrast weightings. These images allow manual or automated classification of plaque components inside the vessel wall. Automated classification requires all sequences to be in alignment, which is hampered by patient motion. In clinical practice, correction of this motion is performed manually. Previous studies applied automated image registration to correct for motion using only nondeformable transformation models and did not perform a detailed quantitative validation. The purpose of this study is to develop an automated accurate 3D registration method, and to extensively validate this method on a large set of patient data. In addition, the authors quantified patient motion during scanning to investigate the need for correction. Methods: MR imaging studies (1.5T, dedicated carotid surface coil, Philips) from 55 TIA/stroke patients with ipsilateral <70% carotid artery stenosis were randomly selected from a larger cohort. Five MR pulse sequences were acquired around the carotid bifurcation, each containing nine transverse slices: T1-weighted turbo field echo, time of flight, T2-weighted turbo spin-echo, and pre- and postcontrast T1-weighted turbo spin-echo images (T1W TSE). The images were manually segmented by delineating the lumen contour in each vessel wall sequence and were manually aligned by applying throughplane and inplane translations to the images. To find the optimal automatic image registration method, different masks, choice of the fixed image, different types of the mutual information image similarity metric, and transformation models including 3D deformable transformation models, were evaluated. Evaluation of the automatic registration results was performed by comparing the lumen segmentations of the fixed image and

Automated registration of multispectral MR vessel wall images of the carotid artery

International Nuclear Information System (INIS)

Klooster, R. van 't; Staring, M.; Reiber, J. H. C.; Lelieveldt, B. P. F.; Geest, R. J. van der; Klein, S.; Kwee, R. M.; Kooi, M. E.

2013-01-01

Purpose: Atherosclerosis is the primary cause of heart disease and stroke. The detailed assessment of atherosclerosis of the carotid artery requires high resolution imaging of the vessel wall using multiple MR sequences with different contrast weightings. These images allow manual or automated classification of plaque components inside the vessel wall. Automated classification requires all sequences to be in alignment, which is hampered by patient motion. In clinical practice, correction of this motion is performed manually. Previous studies applied automated image registration to correct for motion using only nondeformable transformation models and did not perform a detailed quantitative validation. The purpose of this study is to develop an automated accurate 3D registration method, and to extensively validate this method on a large set of patient data. In addition, the authors quantified patient motion during scanning to investigate the need for correction. Methods: MR imaging studies (1.5T, dedicated carotid surface coil, Philips) from 55 TIA/stroke patients with ipsilateral <70% carotid artery stenosis were randomly selected from a larger cohort. Five MR pulse sequences were acquired around the carotid bifurcation, each containing nine transverse slices: T1-weighted turbo field echo, time of flight, T2-weighted turbo spin-echo, and pre- and postcontrast T1-weighted turbo spin-echo images (T1W TSE). The images were manually segmented by delineating the lumen contour in each vessel wall sequence and were manually aligned by applying throughplane and inplane translations to the images. To find the optimal automatic image registration method, different masks, choice of the fixed image, different types of the mutual information image similarity metric, and transformation models including 3D deformable transformation models, were evaluated. Evaluation of the automatic registration results was performed by comparing the lumen segmentations of the fixed image and

Vascular remodeling: A redox-modulated mechanism of vessel caliber regulation.

Science.gov (United States)

Tanaka, Leonardo Y; Laurindo, Francisco R M

2017-08-01

Vascular remodeling, i.e. whole-vessel structural reshaping, determines lumen caliber in (patho)physiology. Here we review mechanisms underlying vessel remodeling, with emphasis in redox regulation. First, we discuss confusing terminology and focus on strictu sensu remodeling. Second, we propose a mechanobiological remodeling paradigm based on the concept of tensional homeostasis as a setpoint regulator. We first focus on shear-mediated models as prototypes of remodeling closely dominated by highly redox-sensitive endothelial function. More detailed discussions focus on mechanosensors, integrins, extracellular matrix, cytoskeleton and inflammatory pathways as potential of mechanisms potentially coupling tensional homeostasis to redox regulation. Further discussion of remodeling associated with atherosclerosis and injury repair highlights important aspects of redox vascular responses. While neointima formation has not shown consistent responsiveness to antioxidants, vessel remodeling has been more clearly responsive, indicating that despite the multilevel redox signaling pathways, there is a coordinated response of the whole vessel. Among mechanisms that may orchestrate redox pathways, we discuss roles of superoxide dismutase activity and extracellular protein disulfide isomerase. We then discuss redox modulation of aneurysms, a special case of expansive remodeling. We propose that the redox modulation of vascular remodeling may reflect (1) remodeling pathophysiology is dominated by a particularly redox-sensitive cell type, e.g., endothelial cells (2) redox pathways are temporospatially coordinated at an organ level across distinct cellular and acellular structures or (3) the tensional homeostasis setpoint is closely connected to redox signaling. The mechanobiological/redox model discussed here can be a basis for improved understanding of remodeling and helps clarifying mechanisms underlying prevalent hard-to-treat diseases. Copyright © 2017 Elsevier Inc. All

An artificial neural network method for lumen and media-adventitia border detection in IVUS.

Science.gov (United States)

Su, Shengran; Hu, Zhenghui; Lin, Qiang; Hau, William Kongto; Gao, Zhifan; Zhang, Heye

2017-04-01

Intravascular ultrasound (IVUS) has been well recognized as one powerful imaging technique to evaluate the stenosis inside the coronary arteries. The detection of lumen border and media-adventitia (MA) border in IVUS images is the key procedure to determine the plaque burden inside the coronary arteries, but this detection could be burdensome to the doctor because of large volume of the IVUS images. In this paper, we use the artificial neural network (ANN) method as the feature learning algorithm for the detection of the lumen and MA borders in IVUS images. Two types of imaging information including spatial, neighboring features were used as the input data to the ANN method, and then the different vascular layers were distinguished accordingly through two sparse auto-encoders and one softmax classifier. Another ANN was used to optimize the result of the first network. In the end, the active contour model was applied to smooth the lumen and MA borders detected by the ANN method. The performance of our approach was compared with the manual drawing method performed by two IVUS experts on 461 IVUS images from four subjects. Results showed that our approach had a high correlation and good agreement with the manual drawing results. The detection error of the ANN method close to the error between two groups of manual drawing result. All these results indicated that our proposed approach could efficiently and accurately handle the detection of lumen and MA borders in the IVUS images. Copyright © 2016 Elsevier Ltd. All rights reserved.

Vertebral Artery Diameter and Flow: Nature or Nurture.

Science.gov (United States)

Tarnoki, Adam Domonkos; Fejer, Bence; Tarnoki, David Laszlo; Littvay, Levente; Lucatelli, Pierleone; Cirelli, Carlo; Fanelli, Fabrizio; Sacconi, Beatrice; Fagnani, Corrado; Medda, Emanuela; Farina, Filippo; Meneghetti, Giorgio; Horvath, Tamas; Pucci, Giacomo; Schillaci, Giuseppe; Stazi, Maria Antonietta; Baracchini, Claudio

2017-09-01

In contrast with the carotid arteries, the vertebral arteries (VAs) show considerable variation in length, caliber, and vessel course. This study investigated whether the variation in diameter and flow characteristics of the VAs might be inherited. A total of 172 Italian twins from Padua, Perugia, and Terni (54 monozygotic, 32 dizygotic) recruited from the Italian Twin Registry underwent B-mode and pulsed-wave Doppler ultrasound assessment of their VAs. VA diameters, peak systolic velocity (PSV) and end diastolic velocity (EDV) were assessed at the level of a horizontal V2 segment. Univariate quantitative genetic modeling was performed. Fourteen percent of the sample had VA hypoplasia. Within pair correlation in monozygotic twins was higher than in dizygotics (.552 vs. .229) for VA diameter. Age- and sex-adjusted genetic effect, under the most parsimonious model, accounted for 54.7% (95% CI: 42.2-69.1%) of the variance of VA diameter, and unshared environmental effect for 45.3% (95% CI: 30.9-57.8%). No heritability was found for the PSV of VA, but shared (34.1%; 95% CI: 16.7-53.7%) and unshared (65.9%; 95% CI: 45.9-83.1%) environmental factors determined the variance. EDV of VA is moderately genetically influenced (42.4%; 95% CI: 16.1-64.9%) and also determined by the unshared environment (57.6%; 95% CI: 34.7-83.7%). The diameter of the VAs is moderately genetically determined. Different factors influence the PSV and EDV of VAs, which may highlight the complex hemodynamic background of VA flow and help to understand the vertebral flow anomalies found by ultrasound. Copyright © 2017 by the American Society of Neuroimaging.

In vitro stent lumen visualisation of various common and newly developed femoral artery stents using MR angiography at 1.5 and 3 tesla.

Science.gov (United States)

Syha, R; Ketelsen, D; Kaempf, M; Mangold, S; Sixt, S; Zeller, T; Springer, F; Schick, F; Claussen, C D; Brechtel, K

2013-02-01

To evaluate stent lumen assessment of various commonly used and newly developed stents for the superficial femoral artery (SFA) using MR angiography (MRA) at 1.5 and 3 T. Eleven nitinol stents and one cobalt-chromium stent were compared regarding stent lumen visualisation using a common three-dimensional MRA sequence. Maximum visible stent lumen width and contrast ratio were analysed in three representative slices for each stent type. A scoring system for lumen visualisation was applied. Nitinol stents showed significantly better performance than the cobalt chromium stent (P stent lumen ranged between 43.4 and 95.5 %, contrast ratio between 7.2 and 110.6 %. Regarding both field strengths, seven of the nitinol stents were classified as "suitable". Three nitinol stents were "limited", and one nitinol stent and the cobalt chromium stent were "not suitable". Intraluminal loss of signal and artefacts of most of the SFA stents do not markedly limit assessment of stent lumen by MRA at 1.5 and 3 T. MRA can thus be considered a valid technique for detection of relevant in-stent restenosis. Applied field strength does not strongly influence stent lumen assessment in general, but proper choice of field strength might be helpful.

A system for the thermal insulation of a pre-stressed concrete vessel

International Nuclear Information System (INIS)

Aubert, Gilles; Petit, Guy.

1975-01-01

This invention concerns the thermal insulation of a pre-stressed concrete vessel for a pressurised water nuclear reactor, this vessel being fitted internally with a leak-proof metal lining. Two rings are placed at the lower and upper parts of the vessel respectively. The upper ring is closed with a cover. These rings differ in diameter, are fitted with a metal insulating and mark the limits of a chamber between the vaporisable fluid and the internal wall of the vessel. This chamber is filled with a fluid in the liquid phase up to the liquid/vapor interface level of the fluid and with a gas above that level, the covering of the rings forming a cold fluid liquid seal. Each ring is supported by the vessel. Leak-proof components take up the radial expansion of the rings [fr

Design of vacuum vessel for Indian Test Facility (INTF) for 100 keV neutral beams

International Nuclear Information System (INIS)

Joshi, Jaydeep; Yadav, Ashish; Gangadharan, Roopesh; Prasad, Rambilas; Ulahannan, Shino; Rotti, Chandramouli; Bandyopadhyay, Mainak; Chakraborty, Arun

2015-01-01

Highlights: • Thickness calculation and optimization for the main shell, ducts, Dishends and top lid on the main shell. • Nozzle and flange design for the port openings. • Support structure design for the main shell and ducts. • FEA validation of the INTF vessel for operational, seismic and lifting condition. - Abstract: The Indian Test Facility (INTF) vacuum vessel is designed to install a full-scale test set-up of Diagnostic Neutral Beam (DNB) [1] for the qualification of beam parameters and the behavior of beam-line components prior to installation and operation in ITER. Vacuum vessel is designed in cylindrical shape having length of ∼9 m with diameter of ∼4.5 m and has a detachable top-lid for mounting as well as removal of internal components during installation and maintenance phases. The Vessel has hemispherical dish-ends with large openings for high-voltage bushing on one side and duct on another side. Vessel is provided with openings for hydraulic, cryo, gas-feed and diagnostics. Vessel duct is composed of three segments with length ranges from 3 m to 5 m with diameter of ∼1.5 m and one vessel at the end to house the second calorimeter. The objective of this paper is to present the design and analysis of vacuum vessel, with respect to its functional and operational requirements. The design calculations are done as per ASME-BPVC SectionVIII-Div.1 and subsequently Finite Element Analysis (FEM) method has been adopted to verify the design.

Design of vacuum vessel for Indian Test Facility (INTF) for 100 keV neutral beams

Energy Technology Data Exchange (ETDEWEB)

Joshi, Jaydeep, E-mail: Jaydeep.joshi@iter-india.org [ITER-India, Institute for Plasma Research, A29, GIDC Electronics Estate, Gandhinagar 382016, Gujarat (India); Yadav, Ashish; Gangadharan, Roopesh [ITER-India, Institute for Plasma Research, A29, GIDC Electronics Estate, Gandhinagar 382016, Gujarat (India); Prasad, Rambilas [Madan Mohan Malaviya University of Technology, Gorakhpur, Uttar Pradesh 273001 (India); Ulahannan, Shino [Airframe Aerodesigns Pvt. Ltd., HAL Airport Exit Road, Old Airport Road, Bengaluru 17 (India); Rotti, Chandramouli; Bandyopadhyay, Mainak; Chakraborty, Arun [ITER-India, Institute for Plasma Research, A29, GIDC Electronics Estate, Gandhinagar 382016, Gujarat (India)

2015-10-15

Highlights: • Thickness calculation and optimization for the main shell, ducts, Dishends and top lid on the main shell. • Nozzle and flange design for the port openings. • Support structure design for the main shell and ducts. • FEA validation of the INTF vessel for operational, seismic and lifting condition. - Abstract: The Indian Test Facility (INTF) vacuum vessel is designed to install a full-scale test set-up of Diagnostic Neutral Beam (DNB) [1] for the qualification of beam parameters and the behavior of beam-line components prior to installation and operation in ITER. Vacuum vessel is designed in cylindrical shape having length of ∼9 m with diameter of ∼4.5 m and has a detachable top-lid for mounting as well as removal of internal components during installation and maintenance phases. The Vessel has hemispherical dish-ends with large openings for high-voltage bushing on one side and duct on another side. Vessel is provided with openings for hydraulic, cryo, gas-feed and diagnostics. Vessel duct is composed of three segments with length ranges from 3 m to 5 m with diameter of ∼1.5 m and one vessel at the end to house the second calorimeter. The objective of this paper is to present the design and analysis of vacuum vessel, with respect to its functional and operational requirements. The design calculations are done as per ASME-BPVC SectionVIII-Div.1 and subsequently Finite Element Analysis (FEM) method has been adopted to verify the design.

A theoretical model describing arterial flow in the DIEP flap related to number and size of perforator vessels.

Science.gov (United States)

Patel, Sameer A; Keller, Alex

2008-11-01

The deep inferior epigastric perforator flap is rapidly becoming a more widely employed method of autologous breast reconstruction. The technical considerations involved in the execution of the flap are many and include the selection of perforators to be incorporated in the flap. We attempt to give a mathematical explanation, based on the physics of flow through vessels and the properties of circuits with multiple resistances in parallel, for the clinical observations which have been arrived at through clinical experience. We compare the system of perforators to a circuit with multiple resistances in parallel. Each of these resistances represents a perforator vessel. In the event that there is only one perforator vessel, this simplifies to a single resistance in series with the capillary bed perfusing the flap. The flow through the flap is optimized by incorporation of the largest diameter perforator. Inclusion of other smaller perforators in addition to the largest diameter perforator will reduce the overall resistance, but this reduction in resistance is dependent on the diameter of the additional perforator and may not be worth the additional trauma of dissection and increased operative time. Incorporating several smaller perforators at the expense of excluding the largest diameter perforator appears to increase the overall resistance, unless the smaller perforators are only slightly smaller. We conclude that the best perfused flap involves use of the largest diameter vessel, that although adding additional perforators will decrease the resistance and increase flow, the magnitude of the benefit depends largely on the calibre of the additional perforator, and that this benefit needs to be weighed against the downside of increased muscle and facial trauma.

Endoscopic visualization of luminal organ and great vessels with three dimensional CT scanner

International Nuclear Information System (INIS)

Kobayashi, Hisashi; Okumura, Toshiyuki; Amemiya, Ryuta; Hasegawa, Hiroshi

1992-01-01

Thirty cases examined by three dimensional CT scanner (3DCT) are reported. The observation of inner view using 3DCT were performed in 12 large vessels with vascular disorder, 10 pulmonary bronchi with lung cancer and 8 common bile ducts involved obstructive disease. In order to visualize interface of the lumen, a new software, which was developed by HITACHI MEDICO Inc., was used. In all cases but one the inner view of the luminal organ was clearly demonstrated as 3D images and it was possible to judge some changes of luminal interface involved by the diseases. The 3DCT endoscopic image might be useful as a new endoscopic technique without fiberscopy. (author)

Differential expression of T- and L-type voltage-dependent calcium channels in renal resistance vessels

DEFF Research Database (Denmark)

Hansen, Pernille B. Lærkegaard; Jensen, Boye L.; Andreasen, D

2001-01-01

The distribution of voltage-dependent calcium channels in kidney pre- and postglomerular resistance vessels was determined at the molecular and functional levels. Reverse transcription-polymerase chain reaction analysis of microdissected rat preglomerular vessels and cultured smooth muscle cells...... on vascular diameter in the afferent arteriole. We conclude that voltage-dependent L- and T-type calcium channels are expressed and of functional significance in renal cortical preglomerular vessels, in juxtamedullary efferent arterioles, and in outer medullary vasa recta, but not in cortical efferent...

Large vessel imaging using cosmic-ray muons

International Nuclear Information System (INIS)

Jenneson, P.M.

2004-01-01

Cosmic-ray muons are assessed for their practical use in the tomographic imaging of the internal composition of large vessels over 2 m in diameter. The technique is based on the attenuation and scattering of cosmic-ray muons passing through a vessel and has advantages over photon-based methods of tomography that it is extendable to object containing high-density materials over many tens of metres. The main disadvantage is the length of time required to produce images of sufficient resolution and hence cosmic ray muon tomography will be most suited to the imaging of large structures whose internal composition is effectively static for the duration of the imaging period. Simulation and theoretical results are presented here which demonstrate the feasibility of cosmic ray muon tomography

In 6- to 8-year-old children, hair cortisol is associated with body mass index and somatic complaints, but not with stress, health-related quality of life, blood pressure, retinal vessel diameters, and cardiorespiratory fitness.

Science.gov (United States)

Gerber, Markus; Endes, Katharina; Brand, Serge; Herrmann, Christian; Colledge, Flora; Donath, Lars; Faude, Oliver; Pühse, Uwe; Hanssen, Henner; Zahner, Lukas

2017-02-01

Hair cortisol measurement has become an increasingly accepted approach in endocrinology and biopsychology. However, while in adult research hair cortisol has been proposed as a relevant biomarker for chronic stress (and its adverse consequences), studies with children are scarce. Therefore, the goal of the present exploratory study was to examine the associations between hair cortisol concentrations (HCCs), stress, and a series of health-related outcomes in a sample of Swiss first grade schoolchildren. The sample consisted of 318 children (53% girls, M age =7.26, SD=0.35). Hair strands were taken near the scalp from a posterior vertex position, and HCCs were tested for the first 3-cm hair segment. Parents provided information about their children's age, gender, parental education, children's stress (recent critical life events, daily hassles), health-related quality of life, and psychosomatic complaints. Body composition, blood pressure, retinal vessel diameters, and cardiorespiratory fitness were measured with established methods. In multiple regression analyses, higher HCCs were weakly associated with increased BMI in girls (β=0.22, pstress, health-related quality of life, blood pressure, retinal vessel diameters, and cardiorespiratory fitness. Although small significant relationships were found between HCCs, BMI and somatic complaints, the findings of this exploratory study challenge the view that HCCs can be used as a reliable biomarker of recent critical life events, daily hassles, health-related quality of life, and cardiovascular health indicators in non-clinical young children. Copyright © 2016 Elsevier Ltd. All rights reserved.

MORPHOMETRIC STUDY OF THE AREOLAR SPACE BETWEEN THE GREAT VESSELS AND THE LUMBAR SPINE

Directory of Open Access Journals (Sweden)

Luis Marchi

2015-12-01

Full Text Available Objective : This work aims to study the areolar space anterior to the lumbar spine, and also the positioning of the large vessels focusing a lateral approach. Methods :This is a morphometric study of 108 cases based on T2 weighted-MRI images in the supine position. The following measurements were performed: lumbar and segmental lordosis; anteroposterior disc diameter; space between the disc/vertebral body and the vessels; bifurcation between the abdominal aorta and the common iliac veins confluence in relation to the lumbar level. Results :The areolar space with respect to the iliac veins, and with the vena cava increased cranially (p<0.001, starting from average 0.6mm at L4-L5 and reaching 8.4mm at L2, while the abdominal aorta showed no increase or decrease pattern across the different levels (p=0.135 ranging from 1.8 to 4.6mm. The diameter of the discs increased distally (p<0.01 as well as the lordosis (p<0.001. The disc diameter was 11% larger when compared to the adjacent vertebral bodies (p<0.001 and that resulted in a smaller distance of the vessels in the disc level than in the level of the adjacent vertebral bodies (p<0.001. The aortic bifurcation was generally ahead of L4 (52% and less frequently at L3-L4 (28% and L4-L5 (18%. The confluence of the veins was usually at the L4-L5 level (38% and at L5 (37%, and less frequently at L4 (26%. Conclusions : There is an identifiable plane between the great vessels and the lumbar spine which is particularly narrow in its distal portion. It is theoretically feasible to reach this plan, handle the anterior complex disc/ALL and protect the great vessels by lateral approach, however, it is challenging.

Submillimeter Diameter Poly(Vinyl Alcohol) Vascular Graft Patency in Rabbit Model

Science.gov (United States)

Cutiongco, Marie F. A.; Kukumberg, Marek; Peneyra, Jonnathan L.; Yeo, Matthew S.; Yao, Jia Y.; Rufaihah, Abdul Jalil; Le Visage, Catherine; Ho, Jackie Pei; Yim, Evelyn K. F.

2016-01-01

Microvascular surgery is becoming a prevalent surgical practice. Replantation, hand reconstruction, orthopedic, and free tissue transfer procedures all rely on microvascular surgery for the repair of venous and arterial defects at the millimeter and submillimeter levels. Often, a vascular graft is required for the procedure as a means to bridge the gap between native arteries. While autologous vessels are desired for their bioactivity and non-thrombogenicity, the tedious harvest process, lack of availability, and caliber or mechanical mismatch contribute to graft failure. Thus, there is a need for an off-the-shelf artificial vascular graft that has low thrombogenic properties and mechanical properties matching those of submillimeter vessels. Poly(vinyl alcohol) hydrogel (PVA) has excellent prospects as a vascular graft due to its bioinertness, low thrombogenicity, high water content, and tunable mechanical properties. Here, we fabricated PVA grafts with submillimeter diameter and mechanical properties that closely approximated those of the rabbit femoral artery. In vitro platelet adhesion and microparticle release assay verified the low thrombogenicity of PVA. A stringent proof-of-concept in vivo test was performed by implanting PVA grafts in rabbit femoral artery with multilevel arterial occlusion. Laser Doppler measurements indicated the improved perfusion of the distal limb after implantation with PVA grafts. Moreover, ultrasound Doppler and angiography verified that the submillimeter diameter PVA vascular grafts remained patent for 2 weeks without the aid of anticoagulant or antithrombotics. Endothelial cells were observed in the luminal surface of one patent PVA graft. The advantageous non-thrombogenic and tunable mechanical properties of PVA that are retained even in the submillimeter diameter dimensions support the application of this biomaterial for vascular replacement in microvascular surgery. PMID:27376059

Influence of a Double-Lumen Extension Tube on Drug Delivery: Examples of Isosorbide Dinitrate and Diazepam.

Directory of Open Access Journals (Sweden)

Aurélie Maiguy-Foinard

Full Text Available Plastic materials such as polyurethane (PUR, polyethylene (PE, polypropylene (PP and polyvinyl chloride (PVC are widely used in double-lumen extension tubing. The purposes of our study were to 1 compare in vitro drug delivery through the double extension tubes available on the market 2 assess the plastic properties of PUR in infusion devices and their impact on drug delivery.The study compared eight double-lumen extension tubes in PUR, co-extruded (PE/PVC plastic and plasticised PVC from different manufacturers. Isosorbide dinitrate and diazepam were used as model compounds to evaluate their sorption on the internal surface of the infusion device. Control experiments were performed using norepinephrine known not to absorb to plastics. Drug concentrations delivered at the egress of extension tubes were determined over time by an analytical spectrophotometric UV-Vis method. The main characteristics of plastics were also determined.Significant differences in the sorption phenomenon were observed among the eight double-lumen extension tubes and between pairs of extension tubes. Mean concentrations of isosorbide dinitrate delivered at the egress of double-lumen extension tubes after a 150-minute infusion (mean values ± standard deviation in percentage of the initial concentrations in the prepared syringes ranged between 80.53 ± 1.66 (one of the PUR tubes and 92.84 ± 2.73 (PE/PVC tube. The same parameters measured during diazepam infusion ranged between 48.58 ± 2.88 (one of the PUR tubes and 85.06 ± 3.94 (PE/PVC tube. The double-lumen extension tubes in PUR were either thermosetting (resin or thermoplastic according to reference.Clinicians must be aware of potential drug interactions with extension tube materials and so must consider their nature as well as the sterilisation method used before selecting an infusion device.

Diffusion MRI for rectal cancer staging: ADC measurements before and after ultrasonographic gel lumen distension

Energy Technology Data Exchange (ETDEWEB)

Palmucci, S., E-mail: spalmucci@sirm.org; Piccoli, M.; Piana, S.; Foti, P.V.; Siverino, R.O.A.; Mauro, L.A.; Milone, P.; Ettorre, G.C.

2017-01-15

Objectives: To compare Apparent Diffusion Coefficient (ADC) measurements in rectal neoplastic lesions before and after lumen distension obtained with sonography transmission gel. Methods: From January 2014 to July 2016, 25 patients (average age 63.7, range 41–85, 18 males) were studied for pre-treatment rectal cancer staging using a 1.5 T MRI. Diffusion MRI was obtained using echo-planar imaging with b = 800 value; all patients were studied acquiring diffusion sequences with and without rectal lumen distension obtained using sonography transmission gel. In both diffusion sequences, two blinded readers calculated border ADC values and small ADC values, drawing regions of interest respectively along tumour borders and far from tumour borders. Mean ADC values among readers − for each type of ADC measurement − were compared using Wilcoxon matched pairs signed rank test. Correlation was assessed using Pearson analysis. Results: Border ADC mean value for diffusion MR sequences without endorectal contrast was 1.122 mm{sup 2}/sec, with 95% Confidence Interval (CI) = 1.02–1.22; using gel lumen distension, higher border ADC mean value of 1.269 mm{sup 2}/s (95% CI = 1.16–1.38) was obtained. Wilcoxon matched pairs signed rank test revealed statistical difference (p < 0.01); a strong Pearson correlation was reported, with r value of 0.69. Small-ADC mean value was 1.038 mm{sup 2}/s (95% CI = 0.91–1.16) for diffusion sequences acquired without endorectal distension and 1.127 mm{sup 2}/s (95% CI = 0.98–1.27) for diffusion sequences obtained after endorectal gel lumen distension. Wilcoxon analysis did not show statistical difference (p = 0.13). A very strong positive correlation was observed, with r value of 0.81. Conclusions: ADC measurements are slightly higher using endorectal sonographic transmission gel; ROI should be traced far from tumour borders, to minimize gel filled-pixel along the interface between lumen and lesion. Further studies are needed to

Diffusion MRI for rectal cancer staging: ADC measurements before and after ultrasonographic gel lumen distension

International Nuclear Information System (INIS)

Palmucci, S.; Piccoli, M.; Piana, S.; Foti, P.V.; Siverino, R.O.A.; Mauro, L.A.; Milone, P.; Ettorre, G.C.

2017-01-01

Objectives: To compare Apparent Diffusion Coefficient (ADC) measurements in rectal neoplastic lesions before and after lumen distension obtained with sonography transmission gel. Methods: From January 2014 to July 2016, 25 patients (average age 63.7, range 41–85, 18 males) were studied for pre-treatment rectal cancer staging using a 1.5 T MRI. Diffusion MRI was obtained using echo-planar imaging with b = 800 value; all patients were studied acquiring diffusion sequences with and without rectal lumen distension obtained using sonography transmission gel. In both diffusion sequences, two blinded readers calculated border ADC values and small ADC values, drawing regions of interest respectively along tumour borders and far from tumour borders. Mean ADC values among readers − for each type of ADC measurement − were compared using Wilcoxon matched pairs signed rank test. Correlation was assessed using Pearson analysis. Results: Border ADC mean value for diffusion MR sequences without endorectal contrast was 1.122 mm 2 /sec, with 95% Confidence Interval (CI) = 1.02–1.22; using gel lumen distension, higher border ADC mean value of 1.269 mm 2 /s (95% CI = 1.16–1.38) was obtained. Wilcoxon matched pairs signed rank test revealed statistical difference (p < 0.01); a strong Pearson correlation was reported, with r value of 0.69. Small-ADC mean value was 1.038 mm 2 /s (95% CI = 0.91–1.16) for diffusion sequences acquired without endorectal distension and 1.127 mm 2 /s (95% CI = 0.98–1.27) for diffusion sequences obtained after endorectal gel lumen distension. Wilcoxon analysis did not show statistical difference (p = 0.13). A very strong positive correlation was observed, with r value of 0.81. Conclusions: ADC measurements are slightly higher using endorectal sonographic transmission gel; ROI should be traced far from tumour borders, to minimize gel filled-pixel along the interface between lumen and lesion. Further studies are needed to investigate better

Vasculites dos médios e grandes vasos Medium and large vessel vasculitis

Directory of Open Access Journals (Sweden)

Hebert Roberto Clivati Brandt

2009-02-01

Full Text Available As vasculites são constituídas por um grande grupo de síndromes caracterizadas por inflamação e necrose da parede dos vasos sangüíneos, resultando em estreitamento ou oclusão do lúmen. A distribuição dos vasos envolvidos varia consideravelmente e serve de base para a classificação das síndromes vasculíticas: grandes vasos (arterite de Takayasu, arterite temporal; pequenos e médios vasos (poliarterite nodosa, síndrome de Churg-Strauss, granulomatose de Wegener, vasculites nas doenças reumáticas; e pequenos vasos (vasculite de hipersensibilidade, púrpura de Henoch-Schonlein, poliangeíte microscópica, crioglobulinemia. Este artigo revisa as vasculites dos médios e grandes vasos e opções terapêuticas atuais; além de oferecer orientação sobre abordagem diagnóstica e tratamento dos pacientes com suspeita de vasculite cutânea.Vasculitis comprises a broad group of syndromes characterized by inflammation and necrosis on the walls of blood vessels, resulting in narrowing or occlusion of the lumen. The distribution of involved blood vessel varies considerably and serves as the basis for one classification of vasculitic syndromes: large vessels (Takayasu arteritis, giant cell arteritis; medium and small muscular arteries (polyarteritis nodosa, Churg-Strauss syndrome, Wegener's granulomatosis, vasculitis in rheumatic diseases; and small vessels ("hypersensitivity" vasculitis, Henoch-Schonlein purpura, microscopic polyangiitis, cryoglobulinemia. This article reviews medium and large vessel vasculitis and current treatment options; it also presents a comprehensive approach to diagnosing and treating patients with suspected cutaneous vasculitis.

Cold source vessel development for the advanced neutron source

Energy Technology Data Exchange (ETDEWEB)

Williams, P.T.; Lucas, A.T. [Oak Ridge National Lab., TN (United States)

1995-09-01

The Advanced Neutron Source (ANS), in its conceptual design phase at Oak Ridge National Laboratory (ORNL), will be a user-oriented neutron research facility that will produce the most intense flux of neutrons in the world. Among its many scientific applications, the productions of cold neutrons is a significant research mission for the ANS. The cold neutrons come from two independent cold sources positioned near the reactor core. Contained by an aluminum alloy vessel, each cold source is a 410 mm diameter sphere of liquid deuterium that functions both as a neutron moderator and a cryogenic coolant. With nuclear heating of the containment vessel and internal baffling, steady-state operation requires close control of the liquid deuterium flow near the vessel`s inner surface. Preliminary thermal-hydraulic analyses supporting the cold source design are being performed with multi-dimensional computational fluid dynamics simulations of the liquid deuterium flow and heat transfer. This paper presents the starting phase of a challenging program and describes the cold source conceptual design, the thermal-hydraulic feasibility studies of the containment vessel, and the future computational and experimental studies that will be used to verify the final design.

Automated retinal vessel type classification in color fundus images

Science.gov (United States)

Yu, H.; Barriga, S.; Agurto, C.; Nemeth, S.; Bauman, W.; Soliz, P.

2013-02-01

Automated retinal vessel type classification is an essential first step toward machine-based quantitative measurement of various vessel topological parameters and identifying vessel abnormalities and alternations in cardiovascular disease risk analysis. This paper presents a new and accurate automatic artery and vein classification method developed for arteriolar-to-venular width ratio (AVR) and artery and vein tortuosity measurements in regions of interest (ROI) of 1.5 and 2.5 optic disc diameters from the disc center, respectively. This method includes illumination normalization, automatic optic disc detection and retinal vessel segmentation, feature extraction, and a partial least squares (PLS) classification. Normalized multi-color information, color variation, and multi-scale morphological features are extracted on each vessel segment. We trained the algorithm on a set of 51 color fundus images using manually marked arteries and veins. We tested the proposed method in a previously unseen test data set consisting of 42 images. We obtained an area under the ROC curve (AUC) of 93.7% in the ROI of AVR measurement and 91.5% of AUC in the ROI of tortuosity measurement. The proposed AV classification method has the potential to assist automatic cardiovascular disease early detection and risk analysis.

Distribution of Different Sized Ocular Surface Vessels in Diabetics and Normal Individuals.

Science.gov (United States)

Banaee, Touka; Pourreza, Hamidreza; Doosti, Hassan; Abrishami, Mojtaba; Ehsaei, Asieh; Basiry, Mohsen; Pourreza, Reza

2017-01-01

To compare the distribution of different sized vessels using digital photographs of the ocular surface of diabetic and normal individuals. In this cross-sectional study, red-free conjunctival photographs of diabetic and normal individuals, aged 30-60 years, were taken under defined conditions and analyzed using a Radon transform-based algorithm for vascular segmentation. The image areas occupied by vessels (AOV) of different diameters were calculated. The main outcome measure was the distribution curve of mean AOV of different sized vessels. Secondary outcome measures included total AOV and standard deviation (SD) of AOV of different sized vessels. Two hundred and sixty-eight diabetic patients and 297 normal (control) individuals were included, differing in age (45.50 ± 5.19 vs. 40.38 ± 6.19 years, P distribution curves of mean AOV differed between patients and controls (smaller AOV for larger vessels in patients; P distribution curve of vessels compared to controls. Presence of diabetes mellitus is associated with contraction of larger vessels in the conjunctiva. Smaller vessels dilate with diabetic retinopathy. These findings may be useful in the photographic screening of diabetes mellitus and retinopathy.

[Successful double-lumen endotracheal tube exchange with a soft-tipped extra firm exchange catheter in a patient with severe subcutaneous emphysema].

Science.gov (United States)

Okamoto, Kaori; Komasawa, Nobuyasu; Ishio, Junichi; Nakano, Shoko; Tatsumi, Shinichi; Minami, Toshiaki

2014-07-01

We report a case of successful double-lumen endotracheal tube exchange with a soft-tipped extra firm exchange catheter in a patient with severe subcutaneous emphysema. A 70-year-old man underwent right lower lobectomy for primary lung cancer under general anesthesia. He developed pneumothorax on postoperative day (POD) 14, which led to subcutaneous emphysema. An emergent operation was performed on POD20 to close the pulmonary fistula under general anesthesia with a single-lumen endotracheal tube and bronchial blocker. Subcutaneous emphysema became worse and pharyngeal emphysema was also suspected; re-operation to close the pulmonary or bronchial fistula was planned. We decided to place a double-lumen tube to precisely detect the fistula. Under the guide of a Pentax-AWS Airwayscope, the single-lumen endotracheal tube was exchanged uneventfully to a 35 Fr double-lumen endotracheal tube with a 110 cm soft-tipped extra firm exchange catheter. The fistula was detected by a leak test and the operation was performed uneventfully, leading to improvement of subcutaneous emphysema.

Dynamics of micro-bubble sonication inside a phantom vessel

KAUST Repository

Qamar, Adnan; Samtaney, Ravi; Bull, Joseph L.

2013-01-01

A model for sonicated micro-bubble oscillations inside a phantom vessel is proposed. The model is not a variant of conventional Rayleigh-Plesset equation and is obtained from reduced Navier-Stokes equations. The model relates the micro-bubble oscillation dynamics with geometric and acoustic parameters in a consistent manner. It predicts micro-bubble oscillation dynamics as well as micro-bubble fragmentation when compared to the experimental data. For large micro-bubble radius to vessel diameter ratios, predictions are damped, suggesting breakdown of inherent modeling assumptions for these cases. Micro-bubble response with acoustic parameters is consistent with experiments and provides physical insight to the micro-bubble oscillation dynamics.

Dynamics of micro-bubble sonication inside a phantom vessel

KAUST Repository

Qamar, Adnan

2013-01-10

A model for sonicated micro-bubble oscillations inside a phantom vessel is proposed. The model is not a variant of conventional Rayleigh-Plesset equation and is obtained from reduced Navier-Stokes equations. The model relates the micro-bubble oscillation dynamics with geometric and acoustic parameters in a consistent manner. It predicts micro-bubble oscillation dynamics as well as micro-bubble fragmentation when compared to the experimental data. For large micro-bubble radius to vessel diameter ratios, predictions are damped, suggesting breakdown of inherent modeling assumptions for these cases. Micro-bubble response with acoustic parameters is consistent with experiments and provides physical insight to the micro-bubble oscillation dynamics.

Clinical Results of Arteriovenous Fistulas Constructed Using Autologous Vessels in End-Stage Renal Disease Patients on Hemodialysis

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Ki Tae Kim

2018-04-01

Full Text Available Background: For hemodialysis patients with end-stage renal disease (ESRD, it is important to construct an efficient vascular access with a superior patency rate. This study investigated the factors influencing the efficiency of arteriovenous fistulas (AVFs constructed using an autologous vessel and evaluated the necessity of ultrasonography as a preoperative tool for AVF construction. Methods: A retrospective analysis was performed of 250 patients in whom an AVF was constructed using an autologous vessel due to ESRD at our institution from January 2009 to April 2016. Results: The 1-, 3-, and 5-year patency rates for all subjects were 87.6%, 85.6%, and 84.4%, respectively. The patients who underwent a preoperative evaluation of their vessels via ultrasonography had better patency rates than those who did not. Superior patency rates were found in patients under 65 years of age or with an anastomotic vein diameter of 3 mm or more. The 1-year patency rate and the diameter of the anastomotic vein showed a positive relationship. Conclusion: Ultrasonography is strongly recommended for AVF construction, and efforts should be made to increase the patency rate in patients over 65. Superior clinical results can be expected when an AVF is made using an autologous vessel with an anastomotic vein diameter of at least 3 mm.

Problems in Pressure Vessel Design and Manufacture

Energy Technology Data Exchange (ETDEWEB)

Hellstroem, O [Uddeholms AB, Degerfors (Sweden); Nilson, Ragnar [AB Atomenergi, Nykoeping (Sweden)

1963-05-15

The general desire by the power reactor process makers to increase power rating and their efforts to involve more advanced thermal behaviour and fuel handling facilities within the reactor vessels are accompanied by an increase in both pressure vessel dimensions and various difficulties in giving practical solutions of design materials and fabrication problems. In any section of this report it is emphasized that difficulties and problems already met with will meet again in the future vessels but then in modified forms and in many cases more pertinent than before. As for the increase in geometrical size it can be postulated that with use of better materials and adjusted fabrication methods the size problems can be taken proper care of. It seems likely that vessels of sufficient large diameter and height for the largest power output, which is judged as interesting in the next ten year period, can be built without developing totally new site fabrication technique. It is, however, supposed that such a fabrication technique will be feasible though at higher specific costs for the same quality requirements as obtained in shop fabrication. By the postulated use of more efficient vessel material with principally the same good features of easy fabrication in different stages such as preparation, welding, heat treatment etc as ordinary or slightly modified carbon steels the increase in wall thickness might be kept low. There exists, however, a development work to be done for low-alloy steels to prove their justified use in large reactor pressure vessels.

Problems in Pressure Vessel Design and Manufacture

International Nuclear Information System (INIS)

Hellstroem, O.; Nilson, Ragnar

1963-05-01

The general desire by the power reactor process makers to increase power rating and their efforts to involve more advanced thermal behaviour and fuel handling facilities within the reactor vessels are accompanied by an increase in both pressure vessel dimensions and various difficulties in giving practical solutions of design materials and fabrication problems. In any section of this report it is emphasized that difficulties and problems already met with will meet again in the future vessels but then in modified forms and in many cases more pertinent than before. As for the increase in geometrical size it can be postulated that with use of better materials and adjusted fabrication methods the size problems can be taken proper care of. It seems likely that vessels of sufficient large diameter and height for the largest power output, which is judged as interesting in the next ten year period, can be built without developing totally new site fabrication technique. It is, however, supposed that such a fabrication technique will be feasible though at higher specific costs for the same quality requirements as obtained in shop fabrication. By the postulated use of more efficient vessel material with principally the same good features of easy fabrication in different stages such as preparation, welding, heat treatment etc as ordinary or slightly modified carbon steels the increase in wall thickness might be kept low. There exists, however, a development work to be done for low-alloy steels to prove their justified use in large reactor pressure vessels

Application of morphological bit planes in retinal blood vessel extraction.

Science.gov (United States)

Fraz, M M; Basit, A; Barman, S A

2013-04-01

The appearance of the retinal blood vessels is an important diagnostic indicator of various clinical disorders of the eye and the body. Retinal blood vessels have been shown to provide evidence in terms of change in diameter, branching angles, or tortuosity, as a result of ophthalmic disease. This paper reports the development for an automated method for segmentation of blood vessels in retinal images. A unique combination of methods for retinal blood vessel skeleton detection and multidirectional morphological bit plane slicing is presented to extract the blood vessels from the color retinal images. The skeleton of main vessels is extracted by the application of directional differential operators and then evaluation of combination of derivative signs and average derivative values. Mathematical morphology has been materialized as a proficient technique for quantifying the retinal vasculature in ocular fundus images. A multidirectional top-hat operator with rotating structuring elements is used to emphasize the vessels in a particular direction, and information is extracted using bit plane slicing. An iterative region growing method is applied to integrate the main skeleton and the images resulting from bit plane slicing of vessel direction-dependent morphological filters. The approach is tested on two publicly available databases DRIVE and STARE. Average accuracy achieved by the proposed method is 0.9423 for both the databases with significant values of sensitivity and specificity also; the algorithm outperforms the second human observer in terms of precision of segmented vessel tree.

Noninvasive diagnosis of thrombus in the heart and large vessels

International Nuclear Information System (INIS)

Masuda, Yoshiaki; Morooka, Nobuhiro; Yoshida, Hideo; Watanabe, Shigeru; Inagaki, Yoshiaki

1984-01-01

The usefulness of two dimensional echocardiography (2-D echocardiography) and x-ray computed tomography (CT) for the diagnosis of thrombi in the cardiac cavity and large vessels was studied by comparing them with the findings of invasive methods. Among 56 subjects with mitral stenosis, left atrial thrombi were noted in 12 cases (16 regions) by CT and 8 cases (9 regions) by 2-D echocardiography. In 16 subjects who underwent operations, one false negative case by CT and 3 false negative and one false positive cases by 2-D echocardiography were found. In 80 subjects with myocardial infarction 2-D echocardiography, CT and left ventriculography (LVG) were performed at approximately the same time. Thrombi were detected in 10 subjects (12.5%) by 2-D echocardiography, in 15 (18.8%) by CT and in 14 (17.5%) by LVG. Although mural thrombi in abdominal aortic aneurysm were detected very easily, thin thrombi surrounding the false lumen of the dissecting aneurysm were not detected ultrasonographically. These thrombi were only detected by the enhanced CT. Our results show the usefulness of both methods for detecting thrombi in the heart and large vessels. CT can distinguish the thrombi more clearly than 2-D echocardiography, but 2-D echocardiography is performed more easily, safely and economically than CT. (author)

MEMS-based handheld fourier domain Doppler optical coherence tomography for intraoperative microvascular anastomosis imaging.

Directory of Open Access Journals (Sweden)

Yong Huang

Full Text Available To demonstrate the feasibility of a miniature handheld optical coherence tomography (OCT imager for real time intraoperative vascular patency evaluation in the setting of super-microsurgical vessel anastomosis.A novel handheld imager Fourier domain Doppler optical coherence tomography based on a 1.3-µm central wavelength swept source for extravascular imaging was developed. The imager was minimized through the adoption of a 2.4-mm diameter microelectromechanical systems (MEMS scanning mirror, additionally a 12.7-mm diameter lens system was designed and combined with the MEMS mirror to achieve a small form factor that optimize functionality as a handheld extravascular OCT imager. To evaluate in-vivo applicability, super-microsurgical vessel anastomosis was performed in a mouse femoral vessel cut and repair model employing conventional interrupted suture technique as well as a novel non-suture cuff technique. Vascular anastomosis patency after clinically successful repair was evaluated using the novel handheld OCT imager.With an adjustable lateral image field of view up to 1.5 mm by 1.5 mm, high-resolution simultaneous structural and flow imaging of the blood vessels were successfully acquired for BALB/C mouse after orthotopic hind limb transplantation using a non-suture cuff technique and BALB/C mouse after femoral artery anastomosis using a suture technique. We experimentally quantify the axial and lateral resolution of the OCT to be 12.6 µm in air and 17.5 µm respectively. The OCT has a sensitivity of 84 dB and sensitivity roll-off of 5.7 dB/mm over an imaging range of 5 mm. Imaging with a frame rate of 36 Hz for an image size of 1000(lateral×512(axial pixels using a 50,000 A-lines per second swept source was achieved. Quantitative vessel lumen patency, lumen narrowing and thrombosis analysis were performed based on acquired structure and Doppler images.A miniature handheld OCT imager that can be used for intraoperative evaluation of

Cerebro-afferent vessel and pupillary basal diameter variation induced by stomatognathic trigeminal proprioception: a case report.

Science.gov (United States)

De Cicco, Vincenzo

2012-09-03

A patient affected by asymmetric hemodynamics of cerebro-afferent vessels underwent duplex color scanner investigations in occlusal proprioceptive un- and rebalance conditions. Pupillometric video-oculographic examinations were performed in order to spot connected trigeminal proprioceptive motor patterns able to interfere on sympathetic autonomic activity. The aim of this case report is to verify if involuntary jaw closing during swallowing, executed in unbalance and rebalance myoelectric activity, would be able to modify cerebral hemodynamics. A 56-year-old Caucasian Italian woman affected by asymmetric blood flow of cerebro-afferent vessels underwent an electromyographic investigation of her occlusal muscles in order to assess their occlusal functional balance. The extreme asymmetry of myoelectric activity in dental occlusion evidenced by electromyographic values suggested the rebalancing of the functions of occlusal muscles through concurrent transcutaneous stimulation of the trigeminal nerve supra- and submandibular motor branches. The above-mentioned method allowed the detection of a symmetric craniomandibular muscular relation that can be kept constant through the use of a cusp bite modeled on the inferior dental arch: called orthotic-syntropic bite for its peculiar use of electrostimulation. A few days later, the patient underwent a duplex color scanner investigation and pupillometric video-oculographic examinations in occlusal unbalance and rebalance conditions. A comparative data analysis showed that an unbalanced dental occlusal function may represent an interferential pattern on cerebral hemodynamics velocity and pupillometric evaluations have proved useful both in the analysis of locus coeruleus functional modalities and as a diagnostic tool in the assessment of pathologies involving locus coeruleus and autonomic systems. The inclusion of myoelectric masseter examinations can be useful in patients with asymmetric hemodynamics of cerebro

Hemosuccus pancreaticus: causa rara de hemorragia digestiva maciça

Directory of Open Access Journals (Sweden)

Fernando Antonio C. Spencer

Full Text Available Hemosuccus pancreaticus is a unusual syndrome manifested by hemorrhage into the pancreatic duct and by blood loss through the ampulla of Vater: It may be caused by tumors, arteriovenous malformation, pancreatic lithiasis, aneurism rupture from adjacent vessels, or erosion of pancreatic and peripancreatic vessels due to chronic pancreatitis. The authors describe a case of massive and recurrent gastrointestinal upper hemorrhage in a 26-year-old man without known risk factors for pancreatitis. This man underwent urgent surgery due to gastrointestinal bleeding during the ínvestigation. During the procedure, blood was found in the intestinal lumen and a tumor in the head of pancreas with two centimeters of diameter: A gastroduodenopancreatectomy was performed. Histological study showed chronic pancreatitis with a fistula from the pancreatic vessels to the Wirsung duct. The patient was discharged without postoperative complications and after months, remains assymptomatic.

Comparative analysis of methods for extracting vessel network on breast MRI images

Science.gov (United States)

Gaizer, Bence T.; Vassiou, Katerina G.; Lavdas, Eleftherios; Arvanitis, Dimitrios L.; Fezoulidis, Ioannis V.; Glotsos, Dimitris T.

2017-11-01

Digital processing of MRI images aims to provide an automatized diagnostic evaluation of regular health screenings. Cancerous lesions are proven to cause an alteration in the vessel structure of the diseased organ. Currently there are several methods used for extraction of the vessel network in order to quantify its properties. In this work MRI images (Signa HDx 3.0T, GE Healthcare, courtesy of University Hospital of Larissa) of 30 female breasts were subjected to three different vessel extraction algorithms to determine the location of their vascular network. The first method is an experiment to build a graph over known points of the vessel network; the second algorithm aims to determine the direction and diameter of vessels at these points; the third approach is a seed growing algorithm, spreading selection to neighbors of the known vessel pixels. The possibilities shown by the different methods were analyzed, and quantitative measurements were performed. The data provided by these measurements showed no clear correlation with the presence or malignancy of tumors, based on the radiological diagnosis of skilled physicians.

Diaphragmatic lymphatic vessel behavior during local skeletal muscle contraction.

Science.gov (United States)

Moriondo, Andrea; Solari, Eleonora; Marcozzi, Cristiana; Negrini, Daniela

2015-02-01

The mechanism through which the stresses developed in the diaphragmatic tissue during skeletal muscle contraction sustain local lymphatic function was studied in 10 deeply anesthetized, tracheotomized adult Wistar rats whose diaphragm was exposed after thoracotomy. To evaluate the direct effect of skeletal muscle contraction on the hydraulic intraluminal lymphatic pressures (Plymph) and lymphatic vessel geometry, the maximal contraction of diaphragmatic fibers adjacent to a lymphatic vessel was elicited by injection of 9.2 nl of 1 M KCl solution among diaphragmatic fibers while Plymph was recorded through micropuncture and vessel geometry via stereomicroscopy video recording. In lymphatics oriented perpendicularly to the longitudinal axis of muscle fibers and located at skeletal muscle contraction (Dmc) decreased to 61.3 ± 1.4% of the precontraction value [resting diameter (Drest)]; however, if injection was at >900 μm from the vessel, Dmc enlarged to 131.1 ± 2.3% of Drest. In vessels parallel to muscle fibers, Dmc increased to 122.8 ± 2.9% of Drest. During contraction, Plymph decreased as much as 22.5 ± 2.6 cmH2O in all submesothelial superficial vessels, whereas it increased by 10.7 ± 5.1 cmH2O in deeper vessels running perpendicular to contracting muscle fibers. Hence, the three-dimensional arrangement of the diaphragmatic lymphatic network seems to be finalized to efficiently exploit the stresses exerted by muscle fibers during the contracting inspiratory phase to promote lymph formation in superficial submesothelial lymphatics and its further propulsion in deeper intramuscular vessels. Copyright © 2015 the American Physiological Society.

The impact of vessel size on vulnerability curves: data and models for within-species variability in saplings of aspen, Populus tremuloides Michx.

Science.gov (United States)

Cai, Jing; Tyree, Melvin T

2010-07-01

The objective of this study was to quantify the relationship between vulnerability to cavitation and vessel diameter within a species. We measured vulnerability curves (VCs: percentage loss hydraulic conductivity versus tension) in aspen stems and measured vessel-size distributions. Measurements were done on seed-grown, 4-month-old aspen (Populus tremuloides Michx) grown in a greenhouse. VCs of stem segments were measured using a centrifuge technique and by a staining technique that allowed a VC to be constructed based on vessel diameter size-classes (D). Vessel-based VCs were also fitted to Weibull cumulative distribution functions (CDF), which provided best-fit values of Weibull CDF constants (c and b) and P(50) = the tension causing 50% loss of hydraulic conductivity. We show that P(50) = 6.166D(-0.3134) (R(2) = 0.995) and that b and 1/c are both linear functions of D with R(2) > 0.95. The results are discussed in terms of models of VCs based on vessel D size-classes and in terms of concepts such as the 'pit area hypothesis' and vessel pathway redundancy.

Laparoscopic prototype for optical sealing of renal blood vessels

Science.gov (United States)

Hardy, Luke A.; Hutchens, Thomas C.; Larson, Eric R.; Gonzalez, David A.; Chang, Chun-Hung; Nau, William H.; Fried, Nathaniel M.

2017-02-01

Energy-based, radiofrequency and ultrasonic devices provide rapid sealing of blood vessels during laparoscopic procedures. We are exploring infrared lasers as an alternative for vessel sealing with less collateral thermal damage. Previous studies demonstrated vessel sealing in an in vivo porcine model using a 1470-nm laser. However, the initial prototype was designed for open surgery and featured tissue clasping and light delivery mechanisms incompatible with laparoscopic surgery. In this study, a laparoscopic prototype similar to devices in surgical use was developed, and tests were conducted on porcine renal blood vessels. The 5-mm-OD prototype featured a traditional Maryland jaw configuration. Laser energy was delivered through a 550-μm-core fiber and side-delivery from the lower jaw, with beam dimensions of 18-mm-length x 1.2-mm-width. The 1470-nm diode laser delivered 68 W with 3 s activation time. A total of 69 porcine renal vessels with mean diameter of 3.3 +/- 1.7 mm were tested, ex vivo. Vessels smaller than 5 mm were consistently sealed (48/51) with burst pressures greater than malignant hypertension blood pressure (180 mmHg), averaging 1038 +/- 474 mmHg. Vessels larger than 5 mm were not consistently sealed (6/18), yielding burst pressures of only 174 +/- 221 mmHg. Seal width, thermal damage zone, and thermal spread averaged 1.7 +/- 0.8, 3.4 +/- 0.7, and 1.0 +/- 0.4 mm. A novel optical laparoscopic prototype with 5-mm- OD shaft integrated within a standard Maryland jaw design consistently sealed vessels less than 5 mm with minimal thermal spread. Further in vivo studies are planned to test performance across a variety of vessels and tissues.

Dual energy CTA of the supraaortic arteries: Technical improvements with a novel dual source CT system

International Nuclear Information System (INIS)

Lell, Michael M.; Hinkmann, Fabian; Nkenke, Emeka; Schmidt, Bernhard; Seidensticker, Peter; Kalender, Willi A.; Uder, Michael; Achenbach, Stephan

2010-01-01

Objectives: Computed tomography angiography (CTA) is a well-accepted imaging modality to evaluate the supraaortic vessels. Initial reports have suggested that dual energy CTA (DE-CTA) can enhance diagnosis by creating bone-free data sets, which can be visualized in 3D, but a number of limitations of this technique have also been addressed. We sought to describe the performance of DE-CTA of the supraaortic vessels with a novel dual source CT system with special emphasis on image quality and post-processing related artifacts. Materials and methods: Thirty-three patients underwent carotid CT angiography on a second generation dual source CT system. Simultaneous acquisitions of 100 and 140 kV data sets in arterial phase were performed. Two examiners evaluated overall bone suppression with a 3-point scale (1 = poor; 3 = excellent) and image quality regarding integrity of the vessel lumen of different vessel segments (n = 26) with a 5-point scale (1 = poor; 5 = excellent), CTA source data served as the reference. Results: Excellent bone suppression could be achieved in the head and neck. Only minor bone remnants occurred, mean score for bone removal was 2.9. Mean score for vessel integrity was 4.3. Eight hundred fifty-seven vessel segments could be evaluated. Six hundred thirty-five segments (74%) showed no lumen alteration, 65 segments (7.6%) lumen alterations 10% resulting in a total luminal reduction 50%, and 113 segments (13.2%) showed a gap in the vessel course (100% total lumen reduction). Artificial gaps of the vessel lumen occurred in 28 vessel segments due to artifacts caused by dental hardware and in all but one (65) ophthalmic arteries. Conclusions: Excellent bone suppression could be achieved, DE imaging with 100 and 140 kV lead to improved image quality and vessel integrity in the shoulder region than previously reported. The ophthalmic artery still cannot be adequately visualized.

[Root anatomical structure and hydraulic traits of three typical shrubs on the sandy lands of northern Shaanxi Province, China].

Science.gov (United States)

Ai, Shao-shui; Li, Yang-yang; Chen, Jia-cun; Chen, Wei-yue

2015-11-01

Root xylem anatomical structure and hydraulic traits of three typical shrubs, i.e., Salix psammophila, Caragana korshinskii and Hippophae rhamnoides, within two soil layers (0-20 cm and 30-50 cm) were compared. The results showed that S. psammophila had a higher leaf water potential than C. korshinskii and H. rhamnoides, the average maximum and minimum lumen diameter (d(max) and d(min), respectively), the average lumen area of vessels (Alum) and the ratio of lumen area of all vessels to xylem area (Aves/Axyl) in S. psammophila roots were also significantly higher than those in C. korshinskii and H. rhamnoides, and the root vessel density (VD) in S. psammophila was the same as that in H. rhamnoides but significantly higher than that in C. korshinskii. Root hydraulic conductivity in S. psammophila was 5 times of C. korshinskii and 2.8 times of H. hamnoides. The vulnerability index in S. psammophila roots was similar to that in C. korshinskii but higher than that in H. hamnoides. S. psammophila belonged to a water-spending species, whereas both C. korshinskii and H. rhamnoides were water-saving species, and C. korshinskii was more drought-resistant than H. rhamnoides. There was no difference of d(max), d(min) and Alum between roots in two soil layers, but roots within in the 30-50 cm soil layer had larger VD and Aves/Axyl. The root specific hydraulic conductivity within the 30-50 cm soil layer was significantly higher than within the surface soil layer, whereas the vulnerability index within the 30-50 cm soil layer was smaller, indicating roots in deep soil layers had higher hydraulic transport efficiency and lower hydraulic vulnerability.

Establishment of an animal model of mice with radiation- injured soft tissue blood vessels

International Nuclear Information System (INIS)

Wang Daiyou; Yu Dahai; Wu Jiaxiao; Wei Shanliang; Wen Yuming

2004-01-01

Objective: The aim of this study was to establish an animal model of mice with radiation-injured soft tissue blood vessels. Methods: Forty male mice were irradiated with 30 Gy on the right leg. After the irradiation was finished each of the 40 male mice was tested with angiography, and its muscle tissues on the bilateral legs were examined with vessel staining assay and electron microscopy. Results: The results showed that the number of vessels on the right leg was less than that on the left leg, the microvessel density, average diameter and average sectional area of the right leg were all lower than those of the left, and the configuration and ultra-structure of vessels were also different between both sides of legs. Conclusion: In the study authors successfully established an animal model of mice with radiation-injured soft tissue blood vessels

Influence of Adaptive Statistical Iterative Reconstruction on coronary plaque analysis in coronary computed tomography angiography

DEFF Research Database (Denmark)

Precht, Helle; Kitslaar, Pieter H; Broersen, Alexander

2016-01-01

performed. Images were reconstructed using FBP, 30% and 60% adaptive statistical IR (ASIR). Coronary plaque analysis was performed as per patient and per vessel (LM, LAD, CX and RCA) measurements. Lumen and vessel volumes and plaque burden measurements were based on automatic detected contours in each...... reconstruction. Lumen and plaque intensity measurements and HU based plaque characterization were based on corrected contours copied to each reconstruction. RESULTS: No significant changes between FBP and 30% ASIR were found except for lumen- (-2.53 HU) and plaque intensities (-1.28 HU). Between FBP and 60% ASIR...... the change in total volume showed an increase of 0.94%, 4.36% and 2.01% for lumen, plaque and vessel, respectively. The change in total plaque burden between FBP and 60% ASIR was 0.76%. Lumen and plaque intensities decreased between FBP and 60% ASIR with -9.90 HU and -1.97 HU, respectively. The total plaque...

Axial vessel widening in arborescent monocots.

Science.gov (United States)

Petit, Giai; DeClerck, Fabrice A J; Carrer, Marco; Anfodillo, Tommaso

2014-02-01

Dicotyledons have evolved a strategy to compensate for the increase in hydraulic resistance to water transport with height growth by widening xylem conduits downwards. In monocots, the accumulation of hydraulic resistance with height should be similar, but the absence of secondary growth represents a strong limitation for the maintenance of xylem hydraulic efficiency during ontogeny. The hydraulic architecture of monocots has been studied but it is unclear how monocots arrange their axial vascular structure during ontogeny to compensate for increases in height. We measured the vessel lumina and estimated the hydraulic diameter (Dh) at different heights along the stem of two arborescent monocots, Bactris gasipaes (Kunth) and Guadua angustifolia (Kunth). For the former, we also estimated the variation in Dh along the leaf rachis. Hydraulic diameter increased basally from the stem apex to the base with a scaling exponent (b) in the range of those reported for dicot trees (b = 0.22 in B. gasipaes; b = 0.31 and 0.23 in G. angustifolia). In B. gasipaes, vessels decrease in Dh from the stem's centre towards the periphery, an opposite pattern compared with dicot trees. Along the leaf rachis, a pattern of increasing Dh basally was also found (b = 0.13). The hydraulic design of the monocots studied revealed an axial pattern of xylem conduits similar to those evolved by dicots to compensate and minimize the negative effect of root-to-leaf length on hydrodynamic resistance to water flow.

Large-scale testing of in-vessel debris cooling through external flooding of the reactor pressure vessel in the CYBL facility

International Nuclear Information System (INIS)

Chu, T.Y.; Bentz, J.H.; Bergeron, K.D.; Slezak, S.E.; Simpson, R.B.

1994-01-01

The possibility of achieving in-vessel core retention by flooding the reactor cavity, or the ''flooded cavity'', is an accident management concept currently under consideration for advanced light water reactors (ALWR), as well as for existing light water reactors (LWR). The CYBL (CYlindrical BoiLing) facility is a facility specifically designed to perform large-scale confirmatory testing of the flooded cavity concept. CYBL has a tank-within-a-tank design; the inner 3.7 m diameter tank simulates the reactor vessel, and the outer tank simulates the reactor cavity. The energy deposition on the bottom head is simulated with an array of radiant heaters. The array can deliver a tailored heat flux distribution corresponding to that resulting from core melt convection. The present paper provides a detailed description of the capabilities of the facility, as well as results of recent experiments with heat flux in the range of interest to those required for in-vessel retention in typical ALWRs. The paper concludes with a discussion of other experiments for the flooded cavity applications

Large-Scale testing of in-vessel debris cooling through external flooding of the reactor pressure vessel in the CYBL facility

International Nuclear Information System (INIS)

Chu, T.Y.; Bentz, J.H.; Bergeron, K.D.; Slezak, S.E.; Simpson, R.B.

1994-01-01

The possibility of achieving in-vessel core retention by flooding the reactor cavity, or the open-quotes flooded cavityclose quotes, is an accident management concept currently under consideration for advanced light water reactors (ALWR), as well as for existing light water reactors (LWR). The CYBL (CYlindrical BoiLing) facility is a facility specifically designed to perform large-scale confirmatory testing of the flooded cavity concept. CYBL has a tank-within-a-tank design; the inner 3.7 m diameter tank simulates the reactor vessel, and the outer tank simulates the reactor cavity. The energy deposition on the bottom head is simulated with an array of radiant heaters. The array can deliver a tailored heat flux distribution corresponding to that resulting from core melt convection. The present paper provides a detailed description of the capabilities of the facility, as well as results of recent experiments with heat flux in the range of interest to those required for in-vessel retention in typical ALWRs. The paper concludes with a discussion of other experiments for the flooded cavity applications

Doppler Ultrasound Detection of Preclinical Changes in Foot Arteries in Early Stage of Type 2 Diabetes

International Nuclear Information System (INIS)

Leoniuk, Jolanta; Łukasiewicz, Adam; Szorc, Małgorzata; Sackiewicz, Izabela; Janica, Jacek; Łebkowska, Urszula

2014-01-01

There are few reports regarding the changes within the vessels in the initial stage of type 2 diabetes. The aim of this study was to estimate the hemodynamic and morphological parameters in foot arteries in type 2 diabetes subjects and to compare these parameters to those obtained in a control group of healthy volunteers. Ultrasound B-mode, color Doppler and pulse wave Doppler imaging of foot arteries was conducted in 37 diabetic patients and 36 non-diabetic subjects to determine their morphological (total vascular diameter and flow lumen diameter) and functional parameters (spectral analysis). In diabetic patients, the overall vascular diameter and wall thickness were statistically significantly larger when compared to the control group in the right dorsalis pedis artery (P=0.01; P=0.001), left dorsalis pedis artery (P=0.007; P=0.006), right posterior tibial artery (P=0.005; P=0.0005), and left posterior tibial artery (P=0.007; P=0.0002). No significant differences were observed in both groups in flow lumen diameters and blood flow parameters (PSV, EDV, PI, RI). In the diabetic group, the level of HbA1c positively correlated with flow resistance index in the right dorsalis pedis artery (r=0.38; P=0.02), right posterior tibial artery (r=0.38; P=0.02) and left posterior tibial artery (r=0.42; P=0.009). The pulsatility index within the dorsalis pedis artery decreased with increased trophic skin changes (r=–0.431, P=0.009). In the diabetic group, overall artery diameters larger than and flow lumina comparable to the control group suggest vessel wall thickening occurring in the early stage of diabetes. Doppler flow parameters are comparable in both groups. In the diabetic group, the level of HbA1c positively correlated with flow resistance index and negative correlation was observed between the intensity of trophic skin changes and the pulsatility index

Double-lumen tubes and auto-PEEP during one-lung ventilation.

Science.gov (United States)

Spaeth, J; Ott, M; Karzai, W; Grimm, A; Wirth, S; Schumann, S; Loop, T

2016-01-01

Double-lumen tubes (DLT) are routinely used to enable one-lung-ventilation (OLV) during thoracic anaesthesia. The flow-dependent resistance of the DLT's bronchial limb may be high as a result of its narrow inner diameter and length, and thus potentially contribute to an unintended increase in positive end-expiratory pressure (auto-PEEP). We therefore studied the impact of adult sized DLTs on the dynamic auto-PEEP during OLV. In this prospective clinical study, dynamic auto-PEEP was determined in 72 patients undergoing thoracic surgery, with right- and left-sided DLTs of various sizes. During OLV, air trapping was provoked by increasing inspiration to expiration ratio from 1:2 to 2:1 (five steps). Based on measured flow rate, airway pressure (Paw) and bronchial pressure (Pbronch), the pressure gradient across the DLT (ΔPDLT) and the total auto-PEEP in the respiratory system (i.e. the lungs, the DLT and the ventilator circuit) were determined. Subsequently the DLT's share in total auto-PEEP was calculated. ΔPDLT was 2.3 (0.7) cm H2O over the entire breathing cycle. At the shortest expiratory time the mean total auto-PEEP was 2.9 (1.5) cm H2O (range 0-5.9 cm H2O). The DLT caused 27 to 31% of the total auto-PEEP. Size and side of the DLT's bronchial limb did not impact auto-PEEP significantly. Although the DLT contributes to the overall auto-PEEP, its contribution is small and independent of size and side of the DLT's bronchial limb. The choice of DLT does not influence the risk of auto-PEEP during OLV to a clinically relevant extent. DRKS00005648. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Angiographic Evaluation of Carotid Artery Grafting with Prefabricated Small-Diameter, Small-Intestinal Submucosa Grafts in Sheep

International Nuclear Information System (INIS)

Pavcnik, Dusan; Obermiller, Josef; Uchida, Barry T.; Van Alstine, William; Edwards, James M.; Landry, Gregory J.; Kaufman, John A.; Keller, Frederick S.; Roesch, Josef

2009-01-01

The purpose of this study was to report the longitudinal angiographic evaluation of prefabricated lyophilized small-intestinal submucosa (SIS) grafts placed in ovine carotid arteries and to demonstrate a variety of complications that developed. A total of 24 grafts, 10 cm long and 6 mm in diameter, were placed surgically as interposition grafts. Graft patency at 1 week was evaluated by Doppler ultrasound, and angiography was used for follow-up at 1 month and at 3 to 4 months. A 90% patency rate was found at 1 week, 65% at 1 month, and 30% at 3 to 4 months. On the patent grafts, angiography demonstrated a variety of changes, such as anastomotic stenoses, graft diffuse dilations and dissections, and aneurysm formation. These findings have not been previously demonstrated angiographically by other investigators reporting results with small-diameter vessel grafts made from fresh small-intestinal submucosa (SIS). The complications found were partially related to the graft construction from four SIS layers. Detailed longitudinal angiographic study should become an essential part of any future evaluation of small-vessel SIS grafting.

Ultrasound assessment of the posterior circumflex humeral artery in elite volleyball players: Aneurysm prevalence, anatomy, branching pattern and vessel characteristics

OpenAIRE

van de Pol, Daan; Maas, Mario; Terpstra, Aart; Pannekoek-Hekman, Marja; Alaeikhanehshir, Sena; Kuijer, P. Paul F. M.; Planken, R. Nils

2016-01-01

Objectives To determine the prevalence of posterior circumflex humeral artery (PCHA) aneurysms and vessel characteristics of the PCHA and deep brachial artery (DBA) in elite volleyball players. Methods Two-hundred and eighty players underwent standardized ultrasound assessment of the dominant arm by a vascular technologist. Assessment included determination of PCHA aneurysms (defined as segmental vessel dilatation ?150 %), PCHA and DBA anatomy, branching pattern, vessel course and diameter. R...

Evolution of regular geometrical shapes in fiber lumens

KAUST Repository

Le, Ngoc Lieu

2017-08-17

The geometry of polymeric hollow fibers for hemodialysis or desalination is a key factor determining their performance. Deformations are frequently observed, but they are rather random. Here we were able to exactly control the shape evolution of the internal channels or lumens of polymeric hollow fibers, leading to polygonal geometries with increasing number of sides. The elasticity of the incipient channel skin and instabilities during fiber formation are affected by the internal coagulant fluid composition and flow rate; and highly influence the polygonal shape. We propose a holistic explanation by analyzing the thermodynamic, kinetic and rheological aspects involved in the skin formation and their synergy.

PdNP Decoration of Halloysite Lumen via Selective Grafting of Ionic Liquid onto the Aluminol Surfaces and Catalytic Application.

Science.gov (United States)

Dedzo, Gustave K; Ngnie, Gaëlle; Detellier, Christian

2016-02-01

The synthesis of selectively deposited palladium nanoparticles (PdNPs) inside tubular halloysite lumens is reported. This specific localization was directed by the selective modification of the aluminol surfaces of the clay mineral through stable Al-O-C bonds. An ionic liquid (1-(2-hydroxyethyl)-3-methylimidazolium) was grafted onto halloysite following the guest displacement method (generally used for kaolinite) using halloysite-DMSO preintercalate. The characterization of this clay nanohybrid material (XRD, NMR, TGA) showed characteristics reminiscent of similar materials synthesized from kaolinite. The grafting on halloysite lumens was also effective without using the DMSO preintercalate. The presence of these new functionalities in halloysite directs the synthesis of uniform PdNPs with size ranging between 3 and 6 nm located exclusively in the lumens. This results from the selective adsorption of PdNPs precursors in functionalized lumens through an anion exchange mechanism followed by in situ reduction. In contrast, the unmodified clay mineral displayed nanoparticles both inside and outside the tubes. These catalysts showed significant catalytic activity for the reduction of 4-nitrophenol (4-NP). The most efficient catalysts were recycled up to three times without reducing significantly the catalytic activities.

Percutaneous transluminal angioplasty of supraaortic vessel

International Nuclear Information System (INIS)

Belli, L.; Puricelli, G.; Cerasano, A.; Cornalba, P.; Rota, L.; Facchinetti, P.

1988-01-01

Sixteen cases are reported of dilatation of supra-aortic vessels; in 14/16 patients the vessel involved was either the subclavian artery or the brachio-cephalich trunk. Special attention is paid to the choice of patients - the ideal one presenting with a single uncalcified lesion, with stenosis more than 50% of diameter; the symptoms have recently appeared, with a significant difference (more than 20 mmHg) in the pressure of the two arms. The technical aspects of the angioplastic procedure are discussed, especially in order to preserve the intracriminal circulation and to limit possible complications. The presence of reversed blood flow in the vertebral artery is extremely important to preserve intracranial circulation from possible embolism; normal flow obtained at the end of the procedure is therefore an useful proof of successful dilatation. The advantages are stressed of dilatation over the surgical technique used in the past. Finally, the importance is emphasized of a correct follow-up and doppler control of supra-aortic circulation

Inter-eye comparison of retinal oximetry and vessel caliber between eyes with asymmetrical glaucoma severity in different glaucoma subtypes

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Cheng CS

2016-07-01

Full Text Available Clarissa Shu Ming Cheng,1,2 Yi Fang Lee,2 Charles Ong,3 Zhu Li Yap,2 Andrew Tsai,2 Aditi Mohla,2 Monisha E Nongpiur,4 Tin Aung,2,4 Shamira A Perera2,4 1Department of Ophthalmology, Tan Tock Seng Hospital, 2Department of Ophthalmology, Singapore National Eye Centre, 3Yong Loo Lin School of Medicine, National University of Singapore, 4Singapore Eye Research Institute, Singapore National Eye Centre, Singapore Background: To compare retinal vessel oxygenation and vessel caliber in primary angle-closure glaucoma (PACG, primary open-angle glaucoma (POAG, normal-tension glaucoma (NTG, and normal controls, as well as between eyes of asymmetrical glaucoma severity.Methods: This was a prospective, cross-sectional study. The 159 subjects (PACG, n=39; POAG, n=41; NTG, n=41; normal controls, n=38 underwent retinal oxygen saturation measurements using the Oxymap T1 Retinal Oximeter, optical coherence tomography, and Humphrey visual field testing. Retinal oxygen saturation and vessel diameter were compared between the glaucoma groups and normal controls, as well as between eyes of asymmetrical glaucoma severity. Kruskal–Wallis test was performed for comparison among different subtypes of glaucoma. Wilcoxon signed-rank test was used to compare the inter-eye differences.Results: Compared to normal controls, arteriolar oxygen saturation was increased in PACG eyes (P=0.048 but not in POAG or NTG eyes. There were no significant differences in oxygen saturation in venules or arteriovenous (AV difference in all three glaucoma groups. Venular diameter was significantly reduced in all glaucoma groups compared to normal controls (P<0.001, but no such change was observed in arteriolar diameter (P=0.10. When comparing between eyes of asymmetrical glaucoma severity, arteriolar oxygen saturation (P=0.03 and AV difference (P=0.04 were significantly higher, while arteriolar diameter was significantly lower (P=0.001 in the worse eye in PACG group. There were no significant

Design features of the KSTAR in-vessel control coils

Energy Technology Data Exchange (ETDEWEB)

Kim, H.K. [National Fusion Research Institute (NFRI), 52 Yeoeun-dong, Yusung-ku, Daejeon, 305-333 (Korea, Republic of)], E-mail: hkkim@nfri.re.kr; Yang, H.L.; Kim, G.H.; Kim, Jin-Yong; Jhang, Hogun; Bak, J.S.; Lee, G.S. [National Fusion Research Institute (NFRI), 52 Yeoeun-dong, Yusung-ku, Daejeon, 305-333 (Korea, Republic of)

2009-06-15

In-vessel control coils (IVCCs) are to be used for the fast plasma position control, field error correction (FEC), and resistive wall mode (RWM) stabilization for the Korea Superconducting Tokamak Advanced Research (KSTAR) device. The IVCC system comprises 16 segments to be unified into a single set to achieve following remarkable engineering advantages; (1) enhancement of the coil system reliability with no welding or brazing works inside the vacuum vessel, (2) simplification in fabrication and installation owing to coils being fabricated outside the vacuum vessel and installed after device assembly, and (3) easy repair and maintenance of the coil system. Each segment is designed in 8 turns coil of 32 mm x 15 mm rectangular oxygen free high conductive copper with a 7 mm diameter internal coolant hole. The conductors are enclosed in 2 mm thick Inconel 625 rectangular welded vacuum jacket with epoxy/glass insulation. Structural analyses were implemented to evaluate structural safety against electromagnetic loads acting on the IVCC for the various operation scenarios using finite element analysis. This paper describes the design features and structural analysis results of the KSTAR in-vessel control coils.

Molecular imaging of tumor blood vessels in prostate cancer.

Science.gov (United States)

Tilki, Derya; Seitz, Michael; Singer, Bernhard B; Irmak, Ster; Stief, Christian G; Reich, Oliver; Ergün, Süleyman

2009-05-01

In the past three decades many efforts have been undertaken to understand the mechanisms of tumor angiogenesis. The introduction of anti-angiogenic drugs in tumor therapy during the last few years necessitates the establishment of new techniques enabling molecular imaging of tumor vascular remodelling. The determination of tumor size as commonly used is not appropriate since the extended necrosis under anti-angiogenic therapy does not necessarily result in the reduction of tumor diameter. The basis for the molecular imaging of tumor blood vessels is the remodelling of the tumor vessels under anti-angiogenic therapy which obviously occurs at an early stage and seems to be a convincing parameter. Beside the enormous progress in this field during the last few years the resolution is still not high enough to evaluate the remodelling of the micro tumor vessels. New imaging approaches combining specific molecular markers for tumor vessels with the different imaging techniques are needed to overcome this issue as exemplarily discussed for prostate cancer in this review. Molecular contrast agents targeting the vasculature will allow clinicians the visualization of vascular remodelling processes taking place under anti-angiogenic therapy and improve tumor diagnosis and follow-up.

ATLAS Supplier Award for the ECT Vacuum Vessels

CERN Multimedia

Jenni, P

On 12 February the Netherlands firm Schelde Exotech was awarded the ATLAS Supplier Award for the construction of the two vacuum vessels for the ATLAS End- Cap Toroid (ECT) magnets. ATLAS Supplier Award ceremonies have now become something of a tradition. For the third consecutive year, ATLAS has given best supplier awards for the most exceptional contributors to the construction of the detector. The Netherlands firm Schelde Exotech has just received the award for the construction of the two vacuum vessels for the ECTs. With a diameter of 11 metres and a volume of 550 cubic metres, the ECT vacuum vessels are obviously impressive in scale. They consist of large aluminium plates and a stainless steel central bore tube. In order to obtain the required undulations, the firm had to develop a special assembly and welding technique. Despite the chambers' imposing size, a very high degree of precision has been achieved in their geometry. Moreover, the chambers, which were delivered in July 2002 to CERN, were built i...

The microbiota mediates pathogen clearance from the gut lumen after non-typhoidal Salmonella diarrhea.

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Kathrin Endt

Full Text Available Many enteropathogenic bacteria target the mammalian gut. The mechanisms protecting the host from infection are poorly understood. We have studied the protective functions of secretory antibodies (sIgA and the microbiota, using a mouse model for S. typhimurium diarrhea. This pathogen is a common cause of diarrhea in humans world-wide. S. typhimurium (S. tm(att, sseD causes a self-limiting gut infection in streptomycin-treated mice. After 40 days, all animals had overcome the disease, developed a sIgA response, and most had cleared the pathogen from the gut lumen. sIgA limited pathogen access to the mucosal surface and protected from gut inflammation in challenge infections. This protection was O-antigen specific, as demonstrated with pathogens lacking the S. typhimurium O-antigen (wbaP, S. enteritidis and sIgA-deficient mice (TCRβ(-/-δ(-/-, J(H (-/-, IgA(-/-, pIgR(-/-. Surprisingly, sIgA-deficiency did not affect the kinetics of pathogen clearance from the gut lumen. Instead, this was mediated by the microbiota. This was confirmed using 'L-mice' which harbor a low complexity gut flora, lack colonization resistance and develop a normal sIgA response, but fail to clear S. tm(att from the gut lumen. In these mice, pathogen clearance was achieved by transferring a normal complex microbiota. Thus, besides colonization resistance ( = pathogen blockage by an intact microbiota, the microbiota mediates a second, novel protective function, i.e. pathogen clearance. Here, the normal microbiota re-grows from a state of depletion and disturbed composition and gradually clears even very high pathogen loads from the gut lumen, a site inaccessible to most "classical" immune effector mechanisms. In conclusion, sIgA and microbiota serve complementary protective functions. The microbiota confers colonization resistance and mediates pathogen clearance in primary infections, while sIgA protects from disease if the host re-encounters the same pathogen. This has

A Strategy for Rapid Construction of Blood Vessel-Like Structures with Complex Cell Alignments.

Science.gov (United States)

Wang, Nuoxin; Peng, Yunhu; Zheng, Wenfu; Tang, Lixue; Cheng, Shiyu; Yang, Junchuan; Liu, Shaoqin; Zhang, Wei; Jiang, Xingyu

2018-04-17

A method is developed that can rapidly produce blood vessel-like structures by bonding cell-laden electrospinning (ES) films layer by layer using fibrin glue within 90 min. This strategy allows control of cell type, cell orientation, and material composition in separate layers. Furthermore, ES films with thicker fibers (polylactic-co-glycolic acid, fiber diameter: ≈3.7 µm) are used as cell-seeding layers to facilitate the cell in-growth; those with thinner fibers (polylactic acid, fiber diameter: ≈1.8 µm) are used as outer reinforcing layers to improve the mechanical strength and reduce the liquid leakage of the scaffold. Cells grow, proliferate, and migrate well in the multilayered structure. This design aims at a new type of blood vessel substitute with flexible control of parameters and implementation of functions. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Single pressure vessel (SPV) nickel-hydrogen battery design

Energy Technology Data Exchange (ETDEWEB)

Coates, D.; Grindstaff, B.; Fox, C. [Eagle-Picher Industries, Inc., Joplin, MO (United States)

1995-07-01

Single pressure vessel (SPV) technology combines an entire multi-cell nickel-hydrogen (NiH{sub 2}) space battery within a single pressure vessel. SPV technology has been developed to improve the performance (volume/mass) of the NiH{sub 2} system at the battery level and ultimately to reduce overall battery cost and increase system reliability. Three distinct SPV technologies are currently under development and in production. Eagle-Picher has license to the COMSAT Laboratories technology, as well as internally developed independent SPV technology. A third technology resulted from the acquisition of Johnson Controls NiH{sub 2} battery assets in June, 1994. SPV batteries are currently being produced in 25 ampere-hour (Ah), 35 Ah and 50 Ah configurations. The battery designs have an overall outside diameter of 10 inches (25.4 centimeters).

Neutron Assay System for Con?nement Vessel Disposition

International Nuclear Information System (INIS)

Frame, Katherine C.; Bourne, Mark M.; Crooks, William J.; Evans, Louise; Mayo, Douglas R.; Miko, David K.; Salazar, William R.; Stange, Sy; Valdez, Jose I.; Vigil, Georgiana M.

2012-01-01

Waste will be removed from confinement vessels remaining from 1970s-era experiments. Los Alamos has 9+ spherical confinement vessels remaining from experiments. Each vessel contains ∼ 500 lbs of radioactive debris such as actinide metals and oxides, metals, powdered silica, graphite, and wires and hardware. In order to dispose of the vessels, debris and contamination must be removed. Neutron assay system was designed to assay vessels before and after cleanout. System requirements are: (1) Modular and moveable; (2) Capable of detecting ∼100g 239 Pu equivalent in a 2-inch thick steel sphere with 6 foot diameter; and (3) Capable of safeguards-quality assays. Initial design parameters arethe use of 4-atm 3 He tubes with length of 6 feet, and 3 He tubes embedded in polyethelene for moderation. This paper describes the calibration of the Confinement Vessel Assay System (CVAS) and quantification of its uncertainties. Assay uncertainty depends on five factors: (1) Statistical uncertainty in the assay measurement; (2) Statistical uncertainty in the background measurement; (3) Statistical uncertainty in the isotopics determination - This should be much smaller than the other uncertainties; (4) Systematic uncertainty due to position bias; and (5) Systematic uncertainty due to fluctuations in cosmic ray spallation. This one can be virtually eliminated by performing the background measurement with an empty vessel - but that may not be possible. We used modeling and experiments to quantify the systematic uncertainties. The calibration assumes a uniform distribution of material, but reality will be different. MCNPX modeling was used to quantify the positional bias. The model was benchmarked to build confidence in its results. Material at top of vessel is 44% greater than amount assayed, according to singles. Material near 19-tube detector is 38% less than amount assayed, according to singles. Cosmic ray spallation contributes significantly to the background. Comparing rates

Tissue-Engineered Vascular Graft of Small Diameter Based on Electrospun Polylactide Microfibers

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P. V. Popryadukhin

2017-01-01

Full Text Available Tubular vascular grafts 1.1 mm in diameter based on poly(L-lactide microfibers were obtained by electrospinning. X-ray diffraction and scanning electron microscopy data demonstrated that the samples treated at T=70°C for 1 h in the fixed state on a cylindrical mandrel possessed dense fibrous structure; their degree of crystallinity was approximately 44%. Strength and deformation stability of these samples were higher than those of the native blood vessels; thus, it was possible to use them in tissue engineering as bioresorbable vascular grafts. The experiments on including implantation into rat abdominal aorta demonstrated that the obtained vascular grafts did not cause pathological reactions in the rats; in four weeks, inner side of the grafts became completely covered with endothelial cells, and fibroblasts grew throughout the wall. After exposure for 12 weeks, resorption of PLLA fibers started, and this process was completed in 64 weeks. Resorbed synthetic fibers were replaced by collagen and fibroblasts. At that time, the blood vessel was formed; its neointima and neoadventitia were close to those of the native vessel in structure and composition.

Maximizing Lumen Gain With Directional Atherectomy.

Science.gov (United States)

Stanley, Gregory A; Winscott, John G

2016-08-01

To describe the use of a low-pressure balloon inflation (LPBI) technique to delineate intraluminal plaque and guide directional atherectomy in order to maximize lumen gain and achieve procedure success. The technique is illustrated in a 77-year-old man with claudication who underwent superficial femoral artery revascularization using a HawkOne directional atherectomy catheter. A standard angioplasty balloon was inflated to 1 to 2 atm during live fluoroscopy to create a 3-dimensional "lumenogram" of the target lesion. Directional atherectomy was performed only where plaque impinged on the balloon at a specific fluoroscopic orientation. The results of the LPBI technique were corroborated with multimodality diagnostic imaging, including digital subtraction angiography, intravascular ultrasound, and intra-arterial pressure measurements. With the LPBI technique, directional atherectomy can routinely achieve <10% residual stenosis, as illustrated in this case, thereby broadly supporting a no-stent approach to lower extremity endovascular revascularization. © The Author(s) 2016.

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

2018-06-01

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.

Three-dimensional photoacoustic endoscopic imaging of the rabbit esophagus.

Science.gov (United States)

Yang, Joon Mo; Favazza, Christopher; Yao, Junjie; Chen, Ruimin; Zhou, Qifa; Shung, K Kirk; Wang, Lihong V

2015-01-01

We report photoacoustic and ultrasonic endoscopic images of two intact rabbit esophagi. To investigate the esophageal lumen structure and microvasculature, we performed in vivo and ex vivo imaging studies using a 3.8-mm diameter photoacoustic endoscope and correlated the images with histology. Several interesting anatomic structures were newly found in both the in vivo and ex vivo images, which demonstrates the potential clinical utility of this endoscopic imaging modality. In the ex vivo imaging experiment, we acquired high-resolution motion-artifact-free three-dimensional photoacoustic images of the vasculatures distributed in the walls of the esophagi and extending to the neighboring mediastinal regions. Blood vessels with apparent diameters as small as 190 μm were resolved. Moreover, by taking advantage of the dual-mode high-resolution photoacoustic and ultrasound endoscopy, we could better identify and characterize the anatomic structures of the esophageal lumen, such as the mucosal and submucosal layers in the esophageal wall, and an esophageal branch of the thoracic aorta. In this paper, we present the first photoacoustic images showing the vasculature of a vertebrate esophagus and discuss the potential clinical applications and future development of photoacoustic endoscopy.

Three-dimensional photoacoustic endoscopic imaging of the rabbit esophagus.

Directory of Open Access Journals (Sweden)

Joon Mo Yang

Full Text Available We report photoacoustic and ultrasonic endoscopic images of two intact rabbit esophagi. To investigate the esophageal lumen structure and microvasculature, we performed in vivo and ex vivo imaging studies using a 3.8-mm diameter photoacoustic endoscope and correlated the images with histology. Several interesting anatomic structures were newly found in both the in vivo and ex vivo images, which demonstrates the potential clinical utility of this endoscopic imaging modality. In the ex vivo imaging experiment, we acquired high-resolution motion-artifact-free three-dimensional photoacoustic images of the vasculatures distributed in the walls of the esophagi and extending to the neighboring mediastinal regions. Blood vessels with apparent diameters as small as 190 μm were resolved. Moreover, by taking advantage of the dual-mode high-resolution photoacoustic and ultrasound endoscopy, we could better identify and characterize the anatomic structures of the esophageal lumen, such as the mucosal and submucosal layers in the esophageal wall, and an esophageal branch of the thoracic aorta. In this paper, we present the first photoacoustic images showing the vasculature of a vertebrate esophagus and discuss the potential clinical applications and future development of photoacoustic endoscopy.

Intravenous injection of artificial red cells and subsequent dye laser irradiation causes deep vessel impairment in an animal model of port-wine stain.

Science.gov (United States)

Rikihisa, Naoaki; Tominaga, Mai; Watanabe, Shoji; Mitsukawa, Nobuyuki; Saito, Yoshiaki; Sakai, Hiromi

2018-03-15

Our previous study proposed using artificial blood cells (hemoglobin vesicles, Hb-Vs) as photosensitizers in dye laser treatment for port-wine stains (PWSs). Dye laser photons are absorbed by red blood cells (RBCs) and hemoglobin (Hb) mixture, which potentially produce more heat and photocoagulation and effectively destroy endothelial cells. Hb-Vs combination therapy will improve clinical outcomes of dye laser treatment for PWSs because very small vessels do not contain sufficient RBCs and they are poor absorbers/heaters of lasers. In the present study, we analyzed the relationship between vessel depth from the skin surface and vessel distraction through dye laser irradiation following intravenous Hb-Vs injection using a chicken wattle model. Hb-Vs were administered and chicken wattles underwent high-energy irradiation at energy higher than in the previous experiments. Hb-Vs location in the vessel lumen was identified to explain its photosensitizer effect using human Hb immunostaining of the irradiated wattles. Laser irradiation with Hb-Vs can effectively destroy deep vessels in animal models. Hb-Vs tend to flow in the marginal zone of both small and large vessels. Increasing laser power combined with Hb-Vs injection contributed for deep vessel impairment because of the synergetic effect of both methods. Newly added Hb tended to flow near the target endothelial cells of the laser treatment. In Hb-Vs and RBC mixture, heat transfer to endothelial cells from absorbers/heater may increase. Hb-Vs function as photosensitizers to destroy deep vessels within a restricted distance that the photon can reach.

CT arterial portography and CT arteriography with a triple-lumen balloon catheter

International Nuclear Information System (INIS)

Murakami, T.; Oi, H.; Hori, M.; Kim, T.; Takahashi, S.; Matsushita, M.; Narumi, Y.; Nakamura, H.

1997-01-01

Purpose: To evaluate the usefulness of the triple-lumen balloon catheter in the serial performance of CT arterial portography (CT-AP) and CT arteriography (CT-A). Material and Methods: A combined CT-AP and CT-A examination of 58 patients was carried out in which a cobra-type triple-lumen balloon catheter was used. CT-AP was performed by injecting contrast medium either into the splenic artery through a side-hole in the catheter proximal to the balloon inflated in the common hepatic artery, or into the superior mesentric artery through an end-hole in the catheter. Then CT-A was serially performed by delivering contrast medium either to the common hepatic artery or the proper hepatic artery from the end-hole, or to the accessory right hepatic artery through a side-hole proximal to the inflated balloon. Results: Sufficient CT-APs were obtained in 53 of the 58 patients (91%), CT-A in 42 (72%), and both in 42 (72%). Incomplete CT-AP was due to technical failure or anatomical anomaly, as was incomplete CT-A. No complications were seen. (orig.)

A model for structural analysis of nuclear reactor pressure vessel flanges

International Nuclear Information System (INIS)

Oliveira, C.A. de.

1987-01-01

Due to the recent Brazilian advances in the nuclear technology area, it has been necessary the development of design and analysis methods for pressurized water reactor components, also as other components of a nuclear plant. This work proposes a methodology for the structural analysis of large diameter nuclear reactor pressure vessel flanges. In the analysis the vessel is divided into shell-of-revolution elements, the flanges are represented by rigid rings, and the bolts are treated as beams. The flexibility method is used for solving the problem. A computer program is shown, and the given results (displacements and stresses) are compared with results obtained by the finite element method. Although developed for nuclear reactor pressure vessel calculations, the program is more general, being possible its use for the analysis of any structure composed by shells of revolution. (author)

Spatial distribution of diffuse, primitive, and classic amyloid-beta deposits and blood vessels in the upper laminae of the frontal cortex in Alzheimer disease.

Science.gov (United States)

Armstrong, R A; Cairns, N J; Lantos, P L

1998-12-01

The spatial distribution of the diffuse, primitive, and classic amyloid-beta deposits was studied in the upper laminae of the superior frontal gyrus in cases of sporadic Alzheimer disease (AD). Amyloid-beta-stained tissue was counterstained with collagen IV to determine whether the spatial distribution of the amyloid-beta deposits along the cortex was related to blood vessels. In all patients, amyloid-beta deposits and blood vessels were aggregated into distinct clusters and in many patients, the clusters were distributed with a regular periodicity along the cortex. The clusters of diffuse and primitive deposits did not coincide with the clusters of blood vessels in most patients. However, the clusters of classic amyloid-beta deposits coincided with those of the large diameter (>10 microm) blood vessels in all patients and with clusters of small-diameter (upper cortical laminae.

Small diameter electrospun silk fibroin vascular grafts: Mechanical properties, in vitro biodegradability, and in vivo biocompatibility.

Science.gov (United States)

Catto, Valentina; Farè, Silvia; Cattaneo, Irene; Figliuzzi, Marina; Alessandrino, Antonio; Freddi, Giuliano; Remuzzi, Andrea; Tanzi, Maria Cristina

2015-09-01

To overcome the drawbacks of autologous grafts currently used in clinical practice, vascular tissue engineering represents an alternative approach for the replacement of small diameter blood vessels. In the present work, the production and characterization of small diameter tubular matrices (inner diameter (ID)=4.5 and 1.5 mm), obtained by electrospinning (ES) of Bombyx mori silk fibroin (SF), have been considered. ES-SF tubular scaffolds with ID=1.5 mm are original, and can be used as vascular grafts in pediatrics or in hand microsurgery. Axial and circumferential tensile tests on ES-SF tubes showed appropriate properties for the specific application. The burst pressure and the compliance of ES-SF tubes were estimated using the Laplace's law. Specifically, the estimated burst pressure was higher than the physiological pressures and the estimated compliance was similar or higher than that of native rat aorta and Goretex® prosthesis. Enzymatic in vitro degradation tests demonstrated a decrease of order and crystallinity of the SF outer surface as a consequence of the enzyme activity. The in vitro cytocompatibility of the ES-SF tubes was confirmed by the adhesion and growth of primary porcine smooth muscle cells. The in vivo subcutaneous implant into the rat dorsal tissue indicated that ES-SF matrices caused a mild host reaction. Thus, the results of this investigation, in which comprehensive morphological and mechanical aspects, in vitro degradation and in vitro and in vivo biocompatibility were considered, indicate the potential suitability of these ES-SF tubular matrices as scaffolds for the regeneration of small diameter blood vessels. Copyright © 2015 Elsevier B.V. All rights reserved.

Improved vessel morphology measurements in contrast-enhanced multi-detector computed tomography coronary angiography with non-linear post-processing

International Nuclear Information System (INIS)

Ferencik, Maros; Lisauskas, Jennifer B.; Cury, Ricardo C.; Hoffmann, Udo; Abbara, Suhny; Achenbach, Stephan; Karl, W. Clem; Brady, Thomas J.; Chan, Raymond C.

2006-01-01

Multi-detector computed tomography (MDCT) permits detection of coronary plaque. However, noise and blurring impair accuracy and precision of plaque measurements. The aim of the study was to evaluate MDCT post-processing based on non-linear image deblurring and edge-preserving noise suppression for measurements of plaque size. Contrast-enhanced MDCT coronary angiography was performed in four subjects (mean age 55 ± 5 years, mean heart rate 54 ± 5 bpm) using a 16-slice scanner (Siemens Sensation 16, collimation 16 x 0.75 mm, gantry rotation 420 ms, tube voltage 120 kV, tube current 550 mAs, 80 mL of contrast). Intravascular ultrasound (IVUS; 40 MHz probe) was performed in one vessel in each patient and served as a reference standard. MDCT vessel cross-sectional images (1 mm thickness) were created perpendicular to centerline and aligned with corresponding IVUS images. MDCT images were processed using a deblurring and edge-preserving noise suppression algorithm. Then, three independent blinded observers segmented lumen and outer vessel boundaries in each modality to obtain vessel cross-sectional area and wall area in the unprocessed MDCT cross-sections, post-processed MDCT cross-sections and corresponding IVUS. The wall area measurement difference for unprocessed and post-processed MDCT images relative to IVUS was 0.4 ± 3.8 mm 2 and -0.2 ± 2.2 mm 2 (p 2 , respectively. In conclusion, MDCT permitted accurate in vivo measurement of wall area and vessel cross-sectional area as compared to IVUS. Post-processing to reduce blurring and noise reduced variability of wall area measurements and reduced measurement bias for both wall area and vessel cross-sectional area

Thrombosis caused by polyurethane double-lumen subclavian superior vena cava catheter and hemodialysis

DEFF Research Database (Denmark)

Wanscher, Maria Rørbæk; Frifelt, J J; Smith-Sivertsen, C

1988-01-01

During an 18-month period, 82 consecutive patients (37 women and 45 men), with a mean age of 50 yr (range 15 to 74), underwent hemodialysis with 91 polyurethane double-lumen subclavian superior vena cava catheters inserted via the right subclavian vein. Upon catheter removal, venograms were...

Evaluation of the conformity of assistential practice in the maintenance of the temporary double-lumen dialysis catheter.

Science.gov (United States)

Rosetti, Késia Alves Gomes; Tronchin, Daisy Maria Rizatto

2014-01-01

to evaluate the conformity of the assistential practice in the maintenance of the temporary double-lumen catheter for hemodialysis, by means of the use of the process indicator, in the University Hospital of the University of São Paulo. a quantitative, exploratory-descriptive and observational study. The sample was made up of 155 observations of persons with temporary double-lumen catheters, in the period March-November 2011, using the Indicator of the Maintenance of the Temporary Double Lumen Catheter for Hemodialysis. the rate of general conformity of the assistential practice corresponded to 65.8%. Of the practice's 13 components, 9 (69.2%) attained 100% conformity. The hygienization of hands by the professionals and the use of a mask by the patients during the disconnection from the hemodialysis had the worst rates (83.9%). although the actions evaluated are implemented in the unit, it is necessary to propose and apply educational strategies with the health team, as well as to institute periodical assessments, so as to raise the conformity rates, ensuring the quality of the hemodialysis services.

Hepatic vessel segmentation for 3D planning of liver surgery experimental evaluation of a new fully automatic algorithm.

Science.gov (United States)

Conversano, Francesco; Franchini, Roberto; Demitri, Christian; Massoptier, Laurent; Montagna, Francesco; Maffezzoli, Alfonso; Malvasi, Antonio; Casciaro, Sergio

2011-04-01

The aim of this study was to identify the optimal parameter configuration of a new algorithm for fully automatic segmentation of hepatic vessels, evaluating its accuracy in view of its use in a computer system for three-dimensional (3D) planning of liver surgery. A phantom reproduction of a human liver with vessels up to the fourth subsegment order, corresponding to a minimum diameter of 0.2 mm, was realized through stereolithography, exploiting a 3D model derived from a real human computed tomographic data set. Algorithm parameter configuration was experimentally optimized, and the maximum achievable segmentation accuracy was quantified for both single two-dimensional slices and 3D reconstruction of the vessel network, through an analytic comparison of the automatic segmentation performed on contrast-enhanced computed tomographic phantom images with actual model features. The optimal algorithm configuration resulted in a vessel detection sensitivity of 100% for vessels > 1 mm in diameter, 50% in the range 0.5 to 1 mm, and 14% in the range 0.2 to 0.5 mm. An average area overlap of 94.9% was obtained between automatically and manually segmented vessel sections, with an average difference of 0.06 mm(2). The average values of corresponding false-positive and false-negative ratios were 7.7% and 2.3%, respectively. A robust and accurate algorithm for automatic extraction of the hepatic vessel tree from contrast-enhanced computed tomographic volume images was proposed and experimentally assessed on a liver model, showing unprecedented sensitivity in vessel delineation. This automatic segmentation algorithm is promising for supporting liver surgery planning and for guiding intraoperative resections. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

Activity of LUMEN (1996-97) Understanding of PbWO4 Scintillator Characteristics and their Optimisation

CERN Document Server

Baccaro, Stefania; Borgia, Bruno; Cecilia, Angelica; Croci, S; Dafinei, Ioan; Diemoz, Marcella; Fabeni, P; Festinesi, Armando; Jarolímek, O; Longo, Egidio; Martini, M; Mihoková, E; Montecchi, Marco; Nikl, M; Nitsch, K; Organtini, Giovanni; Pazzi, G P; Spinolo, G; Vedda, A

1998-01-01

The aim of the LUMEN co-operation, supported by INFN, is to obtain ful experimental characterisation and deep expertise of heavy scintillator for high energy physics. The advantage of this collaboration was mainly in the complementary character of the experimental techniques available in the partner laboratories and in the availability of highly experienced scientists indifferent fields. Furthermore close feedback to technological laboratories preparing on request PWO samples appeared extremely helpful. The present paper reports on the most important results obtained during the LUMEN activity in 1996-97. The aim of the report is to provide also enough useful information for the PWO application and novel ideas to stimulate further interest for new detectors as well as application in different fields.

Impact of obstructive sleep apnea on the occurrence of restenosis after elective percutaneous coronary intervention in ischemic heart disease

Directory of Open Access Journals (Sweden)

Behrendt Dominik

2008-06-01

Full Text Available Abstract Rationale There is growing evidence that obstructive sleep apnea is associated with coronary artery disease. However, there are no data on the course of coronary stenosis after percutaneous coronary intervention in patients with obstructive sleep apnea. Objectives To determine whether sleep apnea is associated with increased late lumen loss and restenosis after percutaneous coronary intervention. Methods 78 patients with coronary artery disease who underwent elective percutaneous coronary intervention were divided in 2 groups: 43 patients with an apnea hypopnea – Index 10/h (group II. Late lumen loss, a marker of restenosis, was determined using quantitative coronary angiography after 6.9 ± 3.1 months. Main results Angiographic restenosis (>50% luminal diameter, was present in 6 (14% of group I and in 9 (25% of group II (p = 0.11. Late lumen loss was significant higher in pt. with an AHI > 10/h (0.7 ± 0.69 mm vs. 0.38 ± 0.37 mm, p = 0.01. Among these 35 patients, 21(60% used their CPAP devices regularly. There was a marginally lower late lumen loss in treated patients, nevertheless, this difference did not reach statistical significance (0.57 ± 0.47 mm vs. 0.99 ± 0.86 mm, p = 0.08. There was no difference in late lumen loss between treated patients and the group I (p = 0.206. Conclusion In summary, patients with OSA and coronary artery disease have a higher degree of late lumen loss, which is a marker of restenosis and vessel remodeling after elective percutaneous intervention.

Automatic design of prestressed concrete vessels

International Nuclear Information System (INIS)

Sotomura, Kentaro; Murazumi, Yasuyuki

1984-01-01

Prestressed concrete appeared after high strnegth steel had been produced, therefore it has the history of only 40 years even in Europe where it was developed. High compressive force is given to concrete beforehand by high strength steel to resist tensile force. It is superior to ordinary steel in strength, economy, rust prevention, fire protection and workability, and it competes with ordinary steel in the fields of bridges, towers, water tanks, water pipes, barges, LPG and LNG tanks, reactor pressure vessels, reactor containment vessels and so on. The design of prestressed concrete containment vessels (PCCV) being constructed in Japan adopts the form of mounting a semi-spherical dome on a cylindrical wall of 43m inside diameter and about 1.5m thickness, and the steel pipe sheaths for inserting tendons are arranged in the wall. The Taisei Construction Co. has developed the PC-ADE system which enables the optimum design of PCCVs. The outline of the automatic design system, the design of tendon arrangement, the preparation of the data on the load for stress analysis, the stress analysis by axisymmetric finite element method and the calculation of cross sections are explained. Design is a creative activity, and in the design of PCCVs also, the intention of designers should be materialized when this program is utilized. (Kako, I.)

Blood Vessel-Derived Acellular Matrix for Vascular Graft Application

Directory of Open Access Journals (Sweden)

Luigi Dall’Olmo

2014-01-01

Full Text Available To overcome the issues connected to the use of autologous vascular grafts and artificial materials for reconstruction of small diameter (<6 mm blood vessels, this study aimed to develop acellular matrix- (AM- based vascular grafts. Rat iliac arteries were decellularized by a detergent-enzymatic treatment, whereas endothelial cells (ECs were obtained through enzymatic digestion of rat skin followed by immunomagnetic separation of CD31-positive cells. Sixteen female Lewis rats (8 weeks old received only AM or previously in vitro reendothelialized AM as abdominal aorta interposition grafts (about 1 cm. The detergent-enzymatic treatment completely removed the cellular part of vessels and both MHC class I and class II antigens. One month after surgery, the luminal surface of implanted AMs was partially covered by ECs and several platelets adhered in the areas lacking cell coverage. Intimal hyperplasia, already detected after 1 month, increased at 3 months. On the contrary, all grafts composed by AM and ECs were completely covered at 1 month and their structure was similar to that of native vessels at 3 months. Taken together, our findings show that prostheses composed of AM preseeded with ECs could be a promising approach for the replacement of blood vessels.

The Clementine Nickel Hydrogen Common Pressure Vessel Battery

OpenAIRE

Garner, Christopher

1994-01-01

The Clementine spacecraft was launched in January 1994 to demonstrate advanced lightweight technologies for the Ballistic Missile Defense Organization (BMDO). One of the key technologies was the first use of a multi-cell nickel hydrogen (NiH2) common pressure vessel (CPV) battery. The 5.0 inch diameter, 22 cell, 15.0 ampere-hour NiH2 CPV battery was manufactured by Johnson Controls Battery Group Inc., (JCBGI). Battery test and integration was performed by the Naval Research Laboratory (NRL). ...

An approach to localize the retinal blood vessels using bit planes and centerline detection.

Science.gov (United States)

Fraz, M M; Barman, S A; Remagnino, P; Hoppe, A; Basit, A; Uyyanonvara, B; Rudnicka, A R; Owen, C G

2012-11-01

The change in morphology, diameter, branching pattern or tortuosity of retinal blood vessels is an important indicator of various clinical disorders of the eye and the body. This paper reports an automated method for segmentation of blood vessels in retinal images. A unique combination of techniques for vessel centerlines detection and morphological bit plane slicing is presented to extract the blood vessel tree from the retinal images. The centerlines are extracted by using the first order derivative of a Gaussian filter in four orientations and then evaluation of derivative signs and average derivative values is performed. Mathematical morphology has emerged as a proficient technique for quantifying the blood vessels in the retina. The shape and orientation map of blood vessels is obtained by applying a multidirectional morphological top-hat operator with a linear structuring element followed by bit plane slicing of the vessel enhanced grayscale image. The centerlines are combined with these maps to obtain the segmented vessel tree. The methodology is tested on three publicly available databases DRIVE, STARE and MESSIDOR. The results demonstrate that the performance of the proposed algorithm is comparable with state of the art techniques in terms of accuracy, sensitivity and specificity. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Development and evaluation of elastomeric hollow fiber membranes as small diameter vascular graft substitutes

Energy Technology Data Exchange (ETDEWEB)

Mercado-Pagán, Ángel E.; Kang, Yunqing [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Findlay, Michael W. [Department of Plastic and Reconstructive Surgery, Stanford University, Stanford, CA (United States); University of Melbourne Department of Surgery, Royal Melbourne Hospital, Parkville, VIC (Australia); Yang, Yunzhi, E-mail: ypyang@stanford.edu [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Department of Materials Science and Engineering, Stanford University, Stanford, CA (United States)

2015-04-01

Engineering of small diameter (< 6 mm) vascular grafts (SDVGs) for clinical use remains a significant challenge. Here, elastomeric polyester urethane (PEU)-based hollow fiber membranes (HFMs) are presented as an SDVG candidate to target the limitations of current technologies and improve tissue engineering designs. HFMs are fabricated by a simple phase inversion method. HFM dimensions are tailored through adjustments to fabrication parameters. The walls of HFMs are highly porous. The HFMs are very elastic, with moduli ranging from 1–4 MPa, strengths from 1–5 MPa, and max strains from 300–500%. Permeability of the HFMs varies from 0.5–3.5 × 10{sup −6} cm/s, while burst pressure varies from 25 to 35 psi. The suture retention forces of HFMs are in the range of 0.8 to 1.2 N. These properties match those of blood vessels. A slow degradation profile is observed for all HFMs, with 71 to 78% of the original mass remaining after 8 weeks, providing a suitable profile for potential cellular incorporation and tissue replacement. Both human endothelial cells and human mesenchymal stem cells proliferate well in the presence of HFMs up to 7 days. These results demonstrate a promising customizable PEU HFMs for small diameter vascular repair and tissue engineering applications. - Highlights: • Hollow fiber membranes (HFMs) were fabricated and evaluated. • HFM properties could be tailored through adjustments to fabrication parameters. • Properties could match or exceed those of blood vessels. • HFM showed excellent compatibility in vitro. • HFMs have the potential to be used for small diameter vascular grafts.

Development and evaluation of elastomeric hollow fiber membranes as small diameter vascular graft substitutes

International Nuclear Information System (INIS)

Mercado-Pagán, Ángel E.; Kang, Yunqing; Findlay, Michael W.; Yang, Yunzhi

2015-01-01

Engineering of small diameter (< 6 mm) vascular grafts (SDVGs) for clinical use remains a significant challenge. Here, elastomeric polyester urethane (PEU)-based hollow fiber membranes (HFMs) are presented as an SDVG candidate to target the limitations of current technologies and improve tissue engineering designs. HFMs are fabricated by a simple phase inversion method. HFM dimensions are tailored through adjustments to fabrication parameters. The walls of HFMs are highly porous. The HFMs are very elastic, with moduli ranging from 1–4 MPa, strengths from 1–5 MPa, and max strains from 300–500%. Permeability of the HFMs varies from 0.5–3.5 × 10 −6 cm/s, while burst pressure varies from 25 to 35 psi. The suture retention forces of HFMs are in the range of 0.8 to 1.2 N. These properties match those of blood vessels. A slow degradation profile is observed for all HFMs, with 71 to 78% of the original mass remaining after 8 weeks, providing a suitable profile for potential cellular incorporation and tissue replacement. Both human endothelial cells and human mesenchymal stem cells proliferate well in the presence of HFMs up to 7 days. These results demonstrate a promising customizable PEU HFMs for small diameter vascular repair and tissue engineering applications. - Highlights: • Hollow fiber membranes (HFMs) were fabricated and evaluated. • HFM properties could be tailored through adjustments to fabrication parameters. • Properties could match or exceed those of blood vessels. • HFM showed excellent compatibility in vitro. • HFMs have the potential to be used for small diameter vascular grafts

Evaluation of the normal thoracic and abdominal aorta diameters by computerized tomography; Avaliacao dos diametros normais da aorta toracica e abdominal pela tomografia computadorizada

Energy Technology Data Exchange (ETDEWEB)

Lucarelli, Claudio Luiz

1995-07-01

The study was undertaken to evaluate, through computerized tomography, the diameters of the normal thoracic and abdominal aorta, as well as they are connected to gender, age and body surface area; and the ratio between measurements obtained at the ascending and descending limbs of the thoracic aorta, and between the abdominal aortic diameters. For that reason, we measured the widest anteroposterior diameters of the thoracic aortas at the levels of the arch, the root, the pulmonary artery, and the thoracic-abdominal transition, as well as the level of the emergence of the superior mesenteric artery, of the renal hila and just cephalad to the bifurcation of the abdominal aortas of 350 patients without cardiovascular diseases who had undergone computerized tomography of the thorax and/or abdomen for any other reasons. Observation and statistic analyses led us to conclude that: 1) both the thoracic and abdominal aortic diameters are reduced from their proximal to their distal portions; 2) the body surface influences the size of the aorta, although only extreme variations alter the vessel's caliber; 3) vessel diameter was observed to gradually increase with age; 4) men were found to have larger diameters than age matched women; 5) the ratio between the ascending and descending aortic diameters varies according to gender and age; 6) the relations between abdominal aortic diameters measured at the level of renal hila and cephalad to the bifurcation are independent from gender and age. But the relation between those measured at the level of the superior mesenteric artery and cephalad to the bifurcation are linked to gender, but not to age. (author)

Evaluation of the normal thoracic and abdominal aorta diameters by computerized tomography; Avaliacao dos diametros normais da aorta toracica e abdominal pela tomografia computadorizada

Energy Technology Data Exchange (ETDEWEB)

Lucarelli, Claudio Luiz

1995-07-01

The study was undertaken to evaluate, through computerized tomography, the diameters of the normal thoracic and abdominal aorta, as well as they are connected to gender, age and body surface area; and the ratio between measurements obtained at the ascending and descending limbs of the thoracic aorta, and between the abdominal aortic diameters. For that reason, we measured the widest anteroposterior diameters of the thoracic aortas at the levels of the arch, the root, the pulmonary artery, and the thoracic-abdominal transition, as well as the level of the emergence of the superior mesenteric artery, of the renal hila and just cephalad to the bifurcation of the abdominal aortas of 350 patients without cardiovascular diseases who had undergone computerized tomography of the thorax and/or abdomen for any other reasons. Observation and statistic analyses led us to conclude that: 1) both the thoracic and abdominal aortic diameters are reduced from their proximal to their distal portions; 2) the body surface influences the size of the aorta, although only extreme variations alter the vessel's caliber; 3) vessel diameter was observed to gradually increase with age; 4) men were found to have larger diameters than age matched women; 5) the ratio between the ascending and descending aortic diameters varies according to gender and age; 6) the relations between abdominal aortic diameters measured at the level of renal hila and cephalad to the bifurcation are independent from gender and age. But the relation between those measured at the level of the superior mesenteric artery and cephalad to the bifurcation are linked to gender, but not to age. (author)

CALiPER Retail Lamps Study 3.2: Lumen and Chromaticity Maintenance of LED A Lamps Operated in Steady-State Conditions

Energy Technology Data Exchange (ETDEWEB)

none,

2014-12-31

This CALiPER report examines lumen depreciation and color shift of 17 different A lamps in steady-state conditions (15 LED, 1 CFL, 1 halogen). The goal of this investigation was to examine the long-term performance of complete LED lamps relative to benchmark halogen and CFL lamps—in this case, A lamps emitting approximately 800 lumens operated continuously at a relatively high ambient temperature of 45°C.

Fuel-coolant interaction visualization test for in-vessel corium retention external reactor vessel cooling (IVR-ERVC) condition

Energy Technology Data Exchange (ETDEWEB)

Na, Young Su; Hong, Seong Ho; Song, Jin Ho; Hong, Seong Wan [Severe Accident and PHWR Safety Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-12-15

A visualization test of the fuel-coolant interaction in the Test for Real cOrium Interaction with water (TROI) test facility was carried out. To experimentally simulate the In-Vessel corium Retention (IVR)- External Reactor Vessel Cooling (ERVC) conditions, prototypic corium was released directly into the coolant water without a free fall in a gas phase before making contact with the coolant. Corium (34.39 kg) consisting of uranium oxide and zirconium oxide with a weight ratio of 8:2 was superheated, and 22.54 kg of the 34.39 kg corium was passed through water contained in a transparent interaction vessel. An image of the corium jet behavior in the coolant was taken by a high-speed camera every millisecond. Thermocouple junctions installed in the vertical direction of the coolant were cut sequentially by the falling corium jet. It was clearly observed that the visualization image of the corium jet taken during the fuel-coolant interaction corresponded with the temperature variations in the direction of the falling melt. The corium penetrated through the coolant, and the jet leading edge velocity was 2.0 m/s. Debris smaller than 1 mm was 15% of the total weight of the debris collected after a fuel-coolant interaction test, and the mass median diameter was 2.9 mm.

Estimation of Scatterer Diameter by Normalized Power Spectrum of High-Frequency Ultrasonic RF Echo for Assessment of Red Blood Cell Aggregation

Science.gov (United States)

Fukushima, Taku; Hasegawa, Hideyuki; Kanai, Hiroshi

2011-07-01

Red blood cell (RBC) aggregation, as one of the determinants of blood viscosity, plays an important role in blood rheology, including the condition of blood. RBC aggregation is induced by the adhesion of RBCs when the electrostatic repulsion between RBCs weakens owing to increases in protein and saturated fatty acid levels in blood, excessive RBC aggregation leads to various circulatory diseases. This study was conducted to establish a noninvasive quantitative method for assessment of RBC aggregation. The power spectrum of ultrasonic RF echoes from nonaggregating RBCs, which shows the frequency property of scattering, exhibits Rayleigh behavior. On the other hand, ultrasonic RF echoes from aggregating RBCs contain the components of reflection, which have no frequency dependence. By dividing the measured power spectrum of echoes from RBCs in the lumen by that of echoes from a posterior wall of the vein in the dorsum manus, the attenuation property of the propagating medium and the frequency responses of transmitting and receiving transducers are removed from the former spectrum. RBC aggregation was assessed by the diameter of a scatterer, which was estimated by minimizing the square difference between the measured normalized power spectrum and the theoretical power spectrum. In this study, spherical scatterers with diameters of 5, 11, 15, and 30 µm were measured in basic experiments. The estimated scatterer diameters were close to the actual diameters. Furthermore, the transient change of the scatterer diameters were measured in an in vivo experiment with respect to a 24-year-old healthy male during the avascularization using a cuff. The estimated diameters (12-22 µm) of RBCs during avascularization were larger than the diameters (4-8 µm) at rest and after recirculation. These results show the possibility of the use of the proposed method for noninvasive assessment of RBC aggregation.

The dual-gate lumen model of renal monoamine transport

Directory of Open Access Journals (Sweden)

Marty Hinz

2010-07-01

Full Text Available Marty Hinz1, Alvin Stein2, Thomas Uncini31Clinical Research, NeuroResearch Clinics, Inc. Cape Coral, Florida, USA; 2Stein Orthopedic Associates, Plantation, Florida, USA; 3DBS Labs, Duluth, Minnesota, USAAbstract: The three-phase response of urinary serotonin and dopamine in subjects ­simultaneously taking amino acid precursors of serotonin and dopamine has been defined.1,2 No model exists regarding the renal etiology of the three-phase response. This writing outlines a model explaining the origin of the three-phase response of urinary serotonin and dopamine. A “dual-gate lumen transporter model” for the basolateral monoamine transporters of the kidneys is proposed as being the etiology of the three-phase urinary serotonin and dopamine responses.Purpose: The purpose of this writing is to document the internal renal function model that has evolved in research during large-scale assay with phase interpretation of urinary serotonin and dopamine.Patients and methods: In excess of 75,000 urinary monoamine assays from more than 7,500 patients were analyzed. The serotonin and the dopamine phase were determined for specimens submitted in the competitive inhibition state. The phase determination findings were then correlated with peer-reviewed literature.Results: The correlation between the three-phase response of urinary serotonin and dopamine with internal renal processes of the bilateral monoamine transporter and the apical monoamine transporter of the proximal convoluted renal tubule cells is defined.Conclusion: The phase of urinary serotonin and dopamine is dependent on the status of the serotonin gate, dopamine gate, and lumen of the basolateral monoamine transporter while in the competitive inhibition state.Keywords: serotonin, dopamine, basolateral, apical, kidney, proximal

Pancreatic Necrosectomy Through a Novel Double-flange Lumen-apposing Covered Metal Stent (Video

Directory of Open Access Journals (Sweden)

Andres Sanchez-Yague

2014-12-01

A double flange lumen apposing FC-SEMS used as a port for necrosectomy significantly improves management of walled-off pancreatic necrosis. Placement of this stents should be considered when multiple necrosectomy sessions are anticipated. Procedure time can be significantly decreased using a catheter that combines a cautery tip and stent delivery system.

Ultrasonographic analysis versus histopathologic evaluation of carotid advanced atherosclerotic stenosis in an experimental rabbit model.

Science.gov (United States)

Mehrad, Hossein; Mokhtari-Dizaji, Manijhe; Ghanaati, Hossein; Shahbazfar, Amir-Ali; Salehnia, Mojdeh

2012-08-01

Advanced carotid atherosclerosis with severe stenosis (>70%) is a major clinical risk factor for ischemic stroke. Our ability to test new protocols for the treatment of atherosclerotic stenosis in humans is limited for obvious ethical reasons; therefore, a suitable animal model is required. The aim of this study was to generate an easily reproducible and inexpensive experimental rabbit carotid model of advanced atherosclerosis with morphological similarities to the human disease and the subsequent assessment of the reliability of B-mode ultrasound technology in the study of lumen area stenosis in this model. Briefly, New Zealand white rabbits underwent primary perivascular cold injury at the right common carotid artery followed by a 1.5% cholesterol-rich diet injury for eight weeks. All of the rabbits' arteries were imaged by B-mode ultrasound weekly, after which the rabbits were sacrificed, and their vessels were processed for histopathology. Ultrasound longitudinal view images from three cardiac cycles were processed by a new computerized analyzing method based on dynamic programming and maximum gradient algorithm for measurement of instantaneous changes in arterial wall thickness and lumen diameter in sequential ultrasound images. Histopathology results showed progressive changes, from the lipid-laden cells and fibrous connective tissue proliferation in neointimal layer, up to the fibro-lipid plaque formation, resulting in vessel wall thickening, remodeling and lumen stenosis. The B-mode ultrasound images and the histologic measurements showed an increase in the mean wall thickness and the lumen area stenosis within eight weeks. Quantitative and morphometric analysis of the mean wall thickness and the lumen area stenosis percentage showed a significant correlation between the B-mode ultrasound and the histological measurements at each time point (R = 0.989 and R = 0.995, p < 0.05, respectively). In conclusion, we successfully produced advanced atherosclerosis in

Influence of Adaptive Statistical Iterative Reconstruction on coronary plaque analysis in coronary computed tomography angiography.

Science.gov (United States)

Precht, Helle; Kitslaar, Pieter H; Broersen, Alexander; Dijkstra, Jouke; Gerke, Oke; Thygesen, Jesper; Egstrup, Kenneth; Lambrechtsen, Jess

The purpose of this study was to study the effect of iterative reconstruction (IR) software on quantitative plaque measurements in coronary computed tomography angiography (CCTA). Thirty patients with a three clinical risk factors for coronary artery disease (CAD) had one CCTA performed. Images were reconstructed using FBP, 30% and 60% adaptive statistical IR (ASIR). Coronary plaque analysis was performed as per patient and per vessel (LM, LAD, CX and RCA) measurements. Lumen and vessel volumes and plaque burden measurements were based on automatic detected contours in each reconstruction. Lumen and plaque intensity measurements and HU based plaque characterization were based on corrected contours copied to each reconstruction. No significant changes between FBP and 30% ASIR were found except for lumen- (-2.53 HU) and plaque intensities (-1.28 HU). Between FBP and 60% ASIR the change in total volume showed an increase of 0.94%, 4.36% and 2.01% for lumen, plaque and vessel, respectively. The change in total plaque burden between FBP and 60% ASIR was 0.76%. Lumen and plaque intensities decreased between FBP and 60% ASIR with -9.90 HU and -1.97 HU, respectively. The total plaque component volume changes were all small with a maximum change of -1.13% of necrotic core between FBP and 60% ASIR. Quantitative plaque measurements only showed modest differences between FBP and the 60% ASIR level. Differences were increased lumen-, vessel- and plaque volumes, decreased lumen- and plaque intensities and a small percentage change in the individual plaque component volumes. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Reliability analysis of pipelines and pressure vessels at nuclear power plants

International Nuclear Information System (INIS)

Klemin, A.I.; Shiverskij, E.A.

1979-01-01

Reliability analysis of pipelines and pressure vessels at NPP is given. The main causes and failure mechanisms of these elements, the ways of reliability improvement and preventing of great damages are considered. The reliability estimation methods both according to the statistical operation data and under the conditions of absence of failure statistics are given. The main characteristics and actual reliability factors of pipelines and pressure vessels of three home NPP: the first in the world NPP, VK-50 and Beloyarsk NPP, are presented. From the start-up there were practically no failures of the pipelines and pressure vessels at the VK-50 pilot installation. The analysis of the operation experience of the first and second blocks of the Beloyarsk NPP, as well as the first in the world NPP, shows that the most part of failures of the pipelines and pressure vessels of these energy blocks with the channel reactors is connected with the coolant leakage at minority pipelines of a small diameter. The most part of failures at individual pipelines of the first and second blocks of the Beloyarsk NPP are connected with the leakages of stuffing boxes of switching off devices. It is noted that serious failures of large pipelines and pressure vessels at all home NPP under operation have not been observed

The Amplatzer vascular plug for large vessel occlusion in the endovascular management of aneurysms

Energy Technology Data Exchange (ETDEWEB)

Ratnam, Lakshmi A.; Walkden, Richard M.; Munneke, Graham J.; Morgan, Robert A.; Belli, Anna-Maria [St.George' s Hospital, Department of Radiology, London (United Kingdom)

2008-09-15

The Amplatzer vascular plug (AVP) is derived from the Amplatzer device used in correction of cardiac septal defects. We present a large series of the use of the AVP in the endovascular management of aneurysms. Three patients with a combination of aortic and peripheral aneurysms underwent embolisation with the AVP. Plugs with 10-16 mm diameter were used and delivered using introducer/guiding sheaths. A total of 16 internal iliac arteries, 2 common iliac arteries (CIA), 4 subclavian (SCA) arteries, 1 superior mesenteric (SMA) and 1 popliteal artery were embolised. Successful occlusion with the AVP was achieved in 21 out of 24 vessels (87.5%), of which 18 (75%) occluded immediately and 3 (12.5%) were delayed occlusions. The three patients who are considered to have failed to occlude with the AVP required the use of additional embolic agents. At the end of the 17-month follow-up all 24 target vessels had occluded. Two patients developed persistent buttock claudication, and one had a left hemiparesis. The AVP is useful as an adjunctive device in the management of aneurysms. It has a particular role in embolisation of large-diameter vessels with a short implantation zone. The device is safe and easy to use. (orig.)

Tissue Engineering of Blood Vessels: Functional Requirements, Progress, and Future Challenges.

Science.gov (United States)

Kumar, Vivek A; Brewster, Luke P; Caves, Jeffrey M; Chaikof, Elliot L

2011-09-01

Vascular disease results in the decreased utility and decreased availability of autologus vascular tissue for small diameter (requires combined approaches from biomaterials science, cell biology, and translational medicine to develop feasible solutions with the requisite mechanical support, a non-fouling surface for blood flow, and tissue regeneration. Over the past two decades interest in blood vessel tissue engineering has soared on a global scale, resulting in the first clinical implants of multiple technologies, steady progress with several other systems, and critical lessons-learned. This review will highlight the current inadequacies of autologus and synthetic grafts, the engineering requirements for implantation of tissue-engineered grafts, and the current status of tissue-engineered blood vessel research.

Structural analysis of the JT-60SA cryostat vessel body

Energy Technology Data Exchange (ETDEWEB)

Botija, José, E-mail: jose.botija@ciemat.es [Association EURATOM – CIEMAT, Avda. Complutense 40, 28040 Madrid (Spain); Alonso, Javier; Fernández, Pilar; Medrano, Mercedes; Ramos, Francisco; Rincon, Esther; Soleto, Alfonso [Association EURATOM – CIEMAT, Avda. Complutense 40, 28040 Madrid (Spain); Davis, Sam; Di Pietro, Enrico; Tomarchio, Valerio [Fusion for Energy, JT-60SA European Home Team, 85748 Garching bei Munchen (Germany); Masaki, Kei; Sakasai, Akira; Shibama, Yusuke [JAEA – Japan Atomic Energy Agency, Naka Fusion Institute, Ibaraki 311-0193 (Japan)

2013-10-15

Highlights: ► Structural analysis to validate the JT-60SA cryostat vessel body design. ► Design code ASME 2007 “Boiler and Pressure Vessel Code. Section VIII”. ► First buckling mode: load multiplier of 10.644, higher than the minimum factor 4.7. ► Elastic and elastic–plastic stress analysis meets ASME against plastic collapse. ► Bolted fasteners have been analyzed showing small gaps closed by strong welding. -- Abstract: The JT-60SA cryostat is a stainless steel vacuum vessel (14 m diameter, 16 m height) which encloses the Tokamak providing the vacuum environment (10{sup −3} Pa) necessary to limit the transmission of thermal loads to the components at cryogenic temperature. It must withstand both external atmospheric pressure during normal operation and internal overpressure in case of an accident. The paper summarizes the structural analyses performed in order to validate the JT-60SA cryostat vessel body design. It comprises several analyses: a buckling analysis to demonstrate stability under the external pressure; an elastic and an elastic–plastic stress analysis according to ASME VIII rules, to evaluate resistance to plastic collapse including localized stress concentrations; and, finally, a detailed analysis with bolted fasteners in order to evaluate the behavior of the flanges, assuring the integrity of the vacuum sealing welds of the cryostat vessel body.

Large-segment tracheal resection and interannular anastomosis with a tension-release technique in the dog.

Science.gov (United States)

Dallman, M J; Bojrab, M J

1982-02-01

Tracheal resection and anastomosis were done on 7 dogs, and a modified procedure to provide optimum first-intention healing, minimum connective tissue proliferation, and optimum epithelialization was used. To test the integrity of the technique at high incision-line tensile forces, 15 to 17 tracheal rings were excised. Excessive tracheal manipulation resulted in an increased amount of lamina propria and submucosa collagenous tissue, increased size and number of blood vessels, and increased leukocytic invasion. Criteria for a successful anastomosis were minimum postoperative coughing, good mucosal apposition and epithelialization, and tracheal lumen diameters that were at least 80% of the preoperative measurement.

Dual-Lumen Chest Port Infection Rates in Patients with Head and Neck Cancer

Energy Technology Data Exchange (ETDEWEB)

Bos, Aaron, E-mail: abos1210@gmail.com; Ahmed, Osman [University of Chicago Medical Center (United States); Jilani, Danial [Wright State University Boonshoft School of Medicine (United States); Giger, Maryellen; Funaki, Brian S.; Zangan, Steven M. [University of Chicago Medical Center (United States)

2015-06-15

PurposeThe aim of this study was to investigate dual-lumen chest port infection rates in patients with head and neck cancer (HNC) compared to those with other malignancies (non-HNC).Materials and MethodsAn IRB-approved retrospective study was performed on 1,094 consecutive chest ports placed over a 2-year period. Patients with poor follow-up (n = 53), no oncologic history (n = 13), or single-lumen ports (n = 183) were excluded yielding a study population of 845 patients. The electronic medical records were queried for demographic information, data regarding ports and infections, and imaging review.ResultsHNC patients experienced more infections (42 vs. 30), an increased infection rate per 1,000 catheter days (0.68 vs. 0.21), and more early infections within 30 days compared to non-HNC patients (10 vs. 6) (p < 0.001, p < 0.001, p = 0.02, respectively). An existing tracheostomy at the time of port placement was associated with infection in the HNC group (p = 0.02) but was not an independent risk factor for infection in the study population overall (p = 0.06). There was a significant difference in age, male gender, and right-sided ports between the HNC and non-HNC groups (p < 0.01, p < 0.001, and p = 0.01), although these were not found to be independent risk factors for infection (p = 0.32, p = 0.76, p = 0.16).ConclusionHNC patients are at increased risk for infection of dual-lumen chest ports placed via a jugular approach compared to patients with other malignancies. Tracheostomy is associated with infection in HNC patients but is not an independent risk factor for infection in the oncologic population as a whole.

Dual-Lumen Chest Port Infection Rates in Patients with Head and Neck Cancer

International Nuclear Information System (INIS)

Bos, Aaron; Ahmed, Osman; Jilani, Danial; Giger, Maryellen; Funaki, Brian S.; Zangan, Steven M.

2015-01-01

PurposeThe aim of this study was to investigate dual-lumen chest port infection rates in patients with head and neck cancer (HNC) compared to those with other malignancies (non-HNC).Materials and MethodsAn IRB-approved retrospective study was performed on 1,094 consecutive chest ports placed over a 2-year period. Patients with poor follow-up (n = 53), no oncologic history (n = 13), or single-lumen ports (n = 183) were excluded yielding a study population of 845 patients. The electronic medical records were queried for demographic information, data regarding ports and infections, and imaging review.ResultsHNC patients experienced more infections (42 vs. 30), an increased infection rate per 1,000 catheter days (0.68 vs. 0.21), and more early infections within 30 days compared to non-HNC patients (10 vs. 6) (p < 0.001, p < 0.001, p = 0.02, respectively). An existing tracheostomy at the time of port placement was associated with infection in the HNC group (p = 0.02) but was not an independent risk factor for infection in the study population overall (p = 0.06). There was a significant difference in age, male gender, and right-sided ports between the HNC and non-HNC groups (p < 0.01, p < 0.001, and p = 0.01), although these were not found to be independent risk factors for infection (p = 0.32, p = 0.76, p = 0.16).ConclusionHNC patients are at increased risk for infection of dual-lumen chest ports placed via a jugular approach compared to patients with other malignancies. Tracheostomy is associated with infection in HNC patients but is not an independent risk factor for infection in the oncologic population as a whole

Coronary angioscopy: a monorail angioscope with movable guide wire.

Science.gov (United States)

Nanto, S; Ohara, T; Mishima, M; Hirayama, A; Komamura, K; Matsumura, Y; Kodama, K

1991-03-01

A new angioscope was devised for easier visualization of the coronary artery. In its tip, the angioscope (Olympus) with an outer diameter of 0.8 mm had a metal lumen, through which a 0.014-in steerable guide wire passed. Using a 8F guiding catheter and a guide wire, it was introduced into the distal coronary artery. With injection of warmed saline through the guiding catheter, the coronary segments were visualized. In the attempted 70 vessels (32 left anterior descending [LAD], 10 right coronary [RCA], 28 left circumflex [LCX]) from 48 patients, 60 vessels (86%) were successfully examined. Twenty-two patients who underwent attempted examination of both LAD and LCX; both coronary arteries were visualized in 19 patients (86%). In the proximal site of the lesion, 40 patients have the diagonal branch or the obtuse marginal branch. In 34 patients (85%) the angioscope was inserted beyond these branches. In 12 very tortuous vessels, eight vessels (67%) were examined. In conclusion, the new monorail coronary angioscope with movable guide wire is useful to examine the stenotic lesions of the coronary artery.

Using perforators as recipient vessels (supermicrosurgery) for free flap reconstruction of the knee region.

Science.gov (United States)

Hong, Joon Pio; Koshima, Isao

2010-03-01

The purpose of this article is to evaluate the feasibility of a perforator as a recipient vessel to reconstruct soft tissue defects of the knee region.From December of 2006 to August of 2008, total of 25 patients underwent reconstructive procedure using either an anterolateral thigh or an upper medial thigh perforator flap. The flaps were anastomosed in a perforator to perforator manner using supermicrosurgery technique.Minimum of 3 perforators were traced around the knee defect. All flaps survived attached to a recipient perforator with artery diameter ranging from 0.4 to 0.9 mm and accompanying veins ranging from 0.4 to 1.2 mm. This approach allowed reduction in time for pedicle and recipient vessel dissection and minimized the trauma involved during isolation of the vessels.Using the perforator as recipient vessel allows an increase in selection for choice of recipient. By using a perforator as recipient, less time is consumed to secure the vessel, does not need long pedicles for flap, is not bound by the condition of major arteries, and minimizes any risk for major vessel injury while having acceptable flap survival.

Standard heart and vessel size on plain films of normal children

International Nuclear Information System (INIS)

Stoever, B.

1986-01-01

Standards of heart size, i.e. heart diameters and heart volume of normal children aged 4-15 years were obtained. In all cases requiring exact heart size determination, heart volume calculation is mandatory in children as well as in adults. Statistical work to date has provided precise calculation of heart volume plain films in the upright position. Additional plain films in prone position are unnecessary because no evident orthostatic influence on heart volume in children can be found. Percentiles of normal heart volume related to body weight representing the best correlation to the individual data are given as well as percentiles related to age. Furthermore ratios of normal vessel size to the height of the 8sup(th) thoracic vertebral body, measured on the same plain film, are given. In addition the ratio of upper to lower lung vessel size is calculated. These ratios are useful criteria in estimating normal vessel size and also in cases with increased pulmonary venous pressure. (orig.) [de

Low Iodine in the Follicular Lumen Caused by Cytoplasm Mis-localization of Sodium Iodide Symporter may Induce Nodular Goiter.

Science.gov (United States)

Huang, Huibin; Shi, Yaxiong; Liang, Bo; Cai, Huiyao; Cai, Qingyan

2017-10-01

Iodine is a key ingredient in the synthesis of thyroid hormones and also a major factor in the regulation of thyroid function. A local reduction of iodine content in follicular lumen leads to overexpression of local thyroid-stimulating hormone receptor (TSHr), which in turn excessively stimulates the regional thyroid tissue, and result in the formation of nodular goiter. In this study, we investigated the relationship between iodine content and sodium iodide symporter (NIS) expression by using the clinical specimens from patients with nodular goiter and explored the pathogenesis triggered by iodine deficiency in nodular goiter. In total, 28 patients were clinically histopathologically confirmed to have nodular goiter and the corresponding adjacent normal thyroid specimens were harvested simultaneously. Western blot and immunohistochemistry were performed to assay NIS expression and localization in thyrocytes of both nodular goiter and adjacent normal thyroid tissues. NIS expression mediated by iodine in follicular lumen was confirmed by follicular model in vitro. Meanwhile, radioscan with iodine-131were conducted on both nodular goiter and adjacent normal thyroid. Our data showed that NIS expression in nodular goiter was significantly higher than that in adjacent normal tissues, which was associated with low iodine in the follicular lumen. Abnormal localization of NIS and lower amount of radioactive iodine-131 were also found in nodular goiter. Our data implied that low iodine in the follicular lumen caused by cytoplasm mis-localization of NIS may induce nodular goiter.

FACTORS AND COMPLICATIONS AFFECTING CATHETER AND TECHNIQUE SURVIVAL WITH PERMANENT SINGLE-LUMEN DIALYSIS CATHETERS

NARCIS (Netherlands)

DEMEESTER, J; VANHOLDER, R; DEROOSE, J; RINGOIR, S

1994-01-01

This long-term study on the outcome of permanent silicone single-lumen dialysis catheters consisted of 43 surgically inserted catheters in 33 patients. All catheters were attached to a pressure-pressure single-cannula dialysis system. Technique and catheter survival were 80 and 59% at 1 year, and 63

Oscillation of Angiogenesis with Vascular Dropout in Diabetic Retinopathy by VESsel GENeration Analysis (VESGEN)

Science.gov (United States)

Parsons-Wingerter, Patricia; Radbakrishnan, Krisbnan; Vickerman, Mary B.; Kaiser, Peter K.

2010-01-01

PURPOSE. Vascular dropout and angiogenesis are hallmarks of the progression of diabetic retinopathy (DR). However, current evaluation of DR relies on grading of secondary vascular effects, such as microaneurysms and hemorrhages, by clinical examination instead of by evaluation of actual vascular changes. The purpose of this study was to map and quantify vascular changes during progression of DR by VESsel GENeration Analysis (VESGEN). METHODS. In this prospective cross-sectional study, 15 eyes with DR were evaluated with fluorescein angiography (FA) and color fundus photography, and were graded using modified Early Treatment Diabetic Retinopathy Study criteria. FA images were separated by semiautomatic image processing into arterial and venous trees. Vessel length density (L(sub v)), number density (N(sub v)), and diameter (D(sub v)) were analyzed in a masked fashion with VESGEN software. Each vascular tree was automatically segmented into branching generations (G(sub 1)...G(sub 8) or G(sub 9)) by vessel diameter and branching. Vascular remodeling status (VRS) for N(sub v) and L(sub v) was graded 1 to 4 for increasing severity of vascular change. RESULTS. By N(sub v) and L(sub v), VRS correlated significantly with the independent clinical diagnosis of mild to proliferative DR (13/15 eyes). N(sub v) and L(sub v) of smaller vessels (G(sub >=6) increased from VRS1 to VRS2 by 2.4 X and 1.6 X, decreased from VRS2 to VRS3 by 0.4 X and 0.6X, and increased from VRS3 to VRS4 by 1.7 X and 1.5 X (P < 0.01). Throughout DR progression, the density of larger vessels (G(sub 1-5)) remained essentially unchanged, and D(sub v1-5) increased slightly. CONCLUSIONS. Vessel density oscillated with the progression of DR. Alternating phases of angiogenesis/neovascularization and vascular dropout were dominated first by remodeling of arteries and subsequently by veins.

Gold nanoparticle induced vasculature damage in radiotherapy: Comparing protons, megavoltage photons, and kilovoltage photons

Energy Technology Data Exchange (ETDEWEB)

Lin, Yuting, E-mail: yutingl188@gmail.com; Paganetti, Harald; Schuemann, Jan [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States); McMahon, Stephen J. [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 and Center for Cancer Research and Cell Biology, Queen’s University Belfast, 97 Lisburn Road, Belfast BT97AE, Northern Ireland (United Kingdom)

2015-10-15

Purpose: The purpose of this work is to investigate the radiosensitizing effect of gold nanoparticle (GNP) induced vasculature damage for proton, megavoltage (MV) photon, and kilovoltage (kV) photon irradiation. Methods: Monte Carlo simulations were carried out using tool for particle simulation (TOPAS) to obtain the spatial dose distribution in close proximity up to 20 μm from the GNPs. The spatial dose distribution from GNPs was used as an input to calculate the dose deposited to the blood vessels. GNP induced vasculature damage was evaluated for three particle sources (a clinical spread out Bragg peak proton beam, a 6 MV photon beam, and two kV photon beams). For each particle source, various depths in tissue, GNP sizes (2, 10, and 20 nm diameter), and vessel diameters (8, 14, and 20 μm) were investigated. Two GNP distributions in lumen were considered, either homogeneously distributed in the vessel or attached to the inner wall of the vessel. Doses of 30 Gy and 2 Gy were considered, representing typical in vivo enhancement studies and conventional clinical fractionation, respectively. Results: These simulations showed that for 20 Au-mg/g GNP blood concentration homogeneously distributed in the vessel, the additional dose at the inner vascular wall encircling the lumen was 43% of the prescribed dose at the depth of treatment for the 250 kVp photon source, 1% for the 6 MV photon source, and 0.1% for the proton beam. For kV photons, GNPs caused 15% more dose in the vascular wall for 150 kVp source than for 250 kVp. For 6 MV photons, GNPs caused 0.2% more dose in the vascular wall at 20 cm depth in water as compared to at depth of maximum dose (Dmax). For proton therapy, GNPs caused the same dose in the vascular wall for all depths across the spread out Bragg peak with 12.7 cm range and 7 cm modulation. For the same weight of GNPs in the vessel, 2 nm diameter GNPs caused three times more damage to the vessel than 20 nm diameter GNPs. When the GNPs were attached

Rapid sealing and cutting of porcine blood vessels, ex vivo, using a high-power, 1470-nm diode laser.

Science.gov (United States)

Giglio, Nicholas C; Hutchens, Thomas C; Perkins, William C; Latimer, Cassandra; Ward, Arlen; Nau, William H; Fried, Nathaniel M

2014-03-01

Suture ligation with subsequent cutting of blood vessels to maintain hemostasis during surgery is time consuming and skill intensive. Energy-based electrosurgical and ultrasonic devices are often used to replace sutures and mechanical clips to provide rapid hemostasis and decrease surgery time. Some of these devices may create undesirably large collateral zones of thermal damage and tissue necrosis, or require separate mechanical blades for cutting. Infrared lasers are currently being explored as alternative energy sources for vessel sealing applications. In a previous study, a 1470-nm laser was used to seal vessels 1 to 6 mm in diameter in 5 s, yielding burst pressures of ∼500  mmHg. The purpose of this study was to provide vessel sealing times comparable with current energy-based devices, incorporate transection of sealed vessels, and demonstrate high vessel burst pressures to provide a safety margin for future clinical use. A 110-W, 1470-nm laser beam was transmitted through a fiber and beam shaping optics, producing a 90-W linear beam 3.0 by 9.5 mm for sealing (400  W/cm2), and 1.1 by 9.6 mm for cutting (1080  W/cm2). A two-step process sealed and then transected ex vivo porcine renal vessels (1.5 to 8.5 mm diameter) in a bench top setup. Seal and cut times were 1.0 s each. A burst pressure system measured seal strength, and histologic measurements of lateral thermal spread were also recorded. All blood vessels tested (n=55 seal samples) were sealed and cut, with total irradiation times of 2.0 s and mean burst pressures of 1305±783  mmHg. Additional unburst vessels were processed for histological analysis, showing a lateral thermal spread of 0.94±0.48  mm (n=14 seal samples). This study demonstrated that an optical-based system is capable of precisely sealing and cutting a wide range of porcine renal vessel sizes and, with further development, may provide an alternative to radiofrequency- and ultrasonic-based vessel sealing devices.

Prediction of L70 lumen maintenance and chromaticity for LEDs using extended Kalman filter models

Energy Technology Data Exchange (ETDEWEB)

Lall, Pradeep; Wei, Junchao; Davis, Lynn

2013-09-30

Solid-state lighting (SSL) luminaires containing light emitting diodes (LEDs) have the potential of seeing excessive temperatures when being transported across country or being stored in non-climate controlled warehouses. They are also being used in outdoor applications in desert environments that see little or no humidity but will experience extremely high temperatures during the day. This makes it important to increase our understanding of what effects high temperature exposure for a prolonged period of time will have on the usability and survivability of these devices. Traditional light sources “burn out” at end-of-life. For an incandescent bulb, the lamp life is defined by B50 life. However, the LEDs have no filament to “burn”. The LEDs continually degrade and the light output decreases eventually below useful levels causing failure. Presently, the TM-21 test standard is used to predict the L70 life of LEDs from LM-80 test data. Several failure mechanisms may be active in a LED at a single time causing lumen depreciation. The underlying TM-21 Model may not capture the failure physics in presence of multiple failure mechanisms. Correlation of lumen maintenance with underlying physics of degradation at system-level is needed. In this paper, Kalman Filter (KF) and Extended Kalman Filters (EKF) have been used to develop a 70-percent Lumen Maintenance Life Prediction Model for LEDs used in SSL luminaires. Ten-thousand hour LM-80 test data for various LEDs have been used for model development. System state at each future time has been computed based on the state space at preceding time step, system dynamics matrix, control vector, control matrix, measurement matrix, measured vector, process noise and measurement noise. The future state of the lumen depreciation has been estimated based on a second order Kalman Filter model and a Bayesian Framework. The measured state variable has been related to the underlying damage using physics-based models. Life

Myofibrotic malformation vessels: unique angiodysplasia toward the progression of hemorrhoidal disease

Science.gov (United States)

Li, Sheng-Long; Jing, Fang-Yan; Ma, Li-Li; Guo, Li-Li; Na, Feng; An, Sheng-Li; Ye, Yan; Yang, Jun-Ming; Bao, Ming; Kang, Dong; Sun, Xiao-Lan; Deng, Yong-Jian

2015-01-01

Background The etiology and pathogenesis of hemorrhoids is unclear, although hemorrhoids are a worldwide disease in men and women, with peak prevalence at 45–65 years of age. Hemorrhoidal cushions as the anal venous plexi are normal anatomical structures from infancy. This study attempts to reveal the angiodysplasia and other pathological changes in association with different degrees of symptomatic hemorrhoids. Materials and methods A total of 281 patients with internal hemorrhoids from degree I to IV underwent hemorrhoidectomy. The vascular changes were analyzed by microscopic assessment and software analysis, with Masson’s trichrome, CD34, and smooth muscle actin. Results The hemorrhoidal tissues exhibited abnormal vessels in the mucosae and submucosae that we termed them as myofibrotic malformation vessels (MMVs). MMVs are not ascribed to arteries or veins because they exhibit enlarged and tortuous lumens with smooth muscle dysplasia and fibrotic deposition in the walls without overlying mucosal ulceration. The muscularis mucosae also showed smooth muscle dysplasia and fibrosis, even if it were interrupted by the intruding MMVs. The statistical data indicated that the severity of all the changes correlate positively with the progression of hemorrhoids (PHemorrhoidal patients are prone for reoccurrence even with prolapsing hemorrhoid when compared with the conventional hemorrhoidectomy. Multiple logistic regression analysis showed that MMVs in mucosal propria, mean thickness of mucosal muscularis layer, and fibrotic changes in MMV were independent risk factors for MMVs in hemorrhoidal disease. Conclusion MMVs and muscularis mucosae dysplasia reciprocally contribute to hemorrhoidal exacerbation. The novel findings of this study propose that the characteristic features of MMVs and muscularis mucosae dysplasia of the anorectal tube ultimately cause symptomatic hemorrhoids, which could affect the clinical management of hemorrhoidal disease through the use of

Percutaneous Selective Embolectomy using a Fogarty Thru-Lumen Catheter for Pancreas Graft Thrombosis: A Case Report

International Nuclear Information System (INIS)

Izaki, Kenta; Yamaguchi, Masato; Matsumoto, Ippei; Shinzeki, Makoto; Ku, Yonson; Sugimura, Kazuro; Sugimoto, Koji

2011-01-01

A 57-year-old woman with a history of diabetes mellitus underwent simultaneous pancreas–kidney transplantation. The pancreaticoduodenal graft was implanted in the right iliac fossa. The donor’s portal vein was anastomosed to the recipient’s inferior vena cava (IVC). Seven days after the surgery, a thrombus was detected in the graft veins. Percutaneous thrombolysis was immediately performed; however, venous congestion was still present. We therefore attempted selective embolectomy using a Fogarty Thru-Lumen Catheter. Thrombi were directed from the graft veins toward the IVC and captured in the IVC filter with complete elimination of the thrombus without any major complications. We present our technique for the successful treatment of pancreas graft thrombosis within a short time period by percutaneous selective embolectomy using a Fogarty Thru-Lumen Catheter.

Distribution of Vascular Patterns in Different Subtypes of Renal Cell Carcinoma. A Morphometric Study in Two Distinct Types of Blood Vessels.

Science.gov (United States)

Ruiz-Saurí, Amparo; García-Bustos, V; Granero, E; Cuesta, S; Sales, M A; Marcos, V; Llombart-Bosch, A

2017-07-01

To analyze the presence of mature and immature vessels as a prognostic factor in patients with renal cell carcinoma and propose a classification of renal cancer tumor blood vessels according to morphometric parameters. Tissue samples were obtained from 121 renal cell carcinoma patients who underwent radical nephrectomy. Staining with CD31 and CD34 was used to differentiate between immature (CD31+) and mature (CD34+) blood vessels. We quantified the microvascular density, microvascular area and different morphometric parameters: maximum diameter, minimum diameter, major axis, minor axis, perimeter, radius ratio and roundness. We found that the microvascular density was higher in CD31+ than CD34+ vessels, but CD34+ vessels were larger than CD31+ vessels, as well as being strongly correlated with the ISUP tumor grade. We also identified four vascular patterns: pseudoacinar, fascicular, reticular and diffuse. Pseudoacinar and fascicular patterns were more frequent in clear cell renal cell carcinoma (37.62 and 35.64% respectively), followed by reticular pattern (21.78%), while in chromophobe tumors the reticular pattern predominated (90%). The isolated pattern was present in all papillary tumors (100%). In healthy renal tissue, the pseudoacinar and isolated patterns were differentially found in the renal cortex and medulla respectively. We defined four distinct vascular patterns significantly related with the ISUP tumor grade in renal cell carcinomas. Further studies in larger series are needed in order to validate these results. Analysis of both mature and immature vessels (CD34+ and CD31+) provides additional information when evaluating microvascular density.

Inservice inspection of Halden BWR pressure vessel

International Nuclear Information System (INIS)

Foerli, O.; Hernes, T.

1978-01-01

A description is given of how the recertification inspection of the 20 years old Halden Reactor pressure vessel was carried out in accordance with the latest ASME-CODES, despite the fact that inspection accessibility was poor. As no volumetric inspection had been carried out since the preservice radiography in 1957, the ultrasonic inspection included the high flux region of all welds. In total 70% of longitudinal welds and 20% of bottom circumferential welds were inspected as well as the bottom nozzle connection. The vessel was not designed with provisions for inservice inspection, the welds are unaccessible from the outside and removal of the lid is virtually impossible. The ultrasonic probes could only be loaded through 77 mm diameter holes in the top lid and remotely positioned inside the vessel. The inspection was performed using 450C and 60OC 1 MHz angle probes and 2.25 MHz normal probes in immersion technique. In a zone around the welds, small regions with lack of bonding between the stainless steel cladding and the boiler steel were revealed. One root defect known and accepted from the preservice radiographs was examined. The defect was found to be 6x30mm as a maximum and well within acceptable limits according to the fracture mechanics analysis method recommended in ASME X1. The inspection required a period of three weeks' work in the reactor hall. (UK)

Possible impact of iridium-192 source centering on restenosis rate after femoro-popliteal angioplasty and endovascular brachytherapy in Vienna-2 study

International Nuclear Information System (INIS)

Pokrajac, Boris; Schmid, Rainer; Kirisits, Christian; Mock, Ulrike; Fellner, Claudia; Wambersie, Andre; Poetter, Richard; Minar, Erich

2002-01-01

Purpose: Endovascular brachytherapy (EVBT) has been proven to significantly reduce restenosis after percutaneous transluminal angioplasty (PTA). The object of this analysis was to assess the possible correlation between iridium-192 source non-centering and angiographic-determined restenosis. Materials and methods: A total of 113 patients with long-segment lesions of the superficial femoro-popliteal artery (SFA) were randomized to receive either PTA alone or PTA followed by EVBT in the Vienna-2 study. This analysis was performed on a subgroup of 34 out of 57 patients, who received PTA+EVBT. Angiographic restenosis was defined as lumen reduction of more than 50%. Angiograms taken immediately after PTA (34 patients) and at follow-up (25 patients) were analyzed. The distance between the vessel wall and the actual position of the source at the time of EVBT was measured (in mm) and correlated with the follow-up vessel lumen diameter. Measurements were performed at points at a distance of 10 mm from each other. The dose was determined at the luminal surface and at the reference depth of 2 mm into the vessel wall for different distances from the source. Results: Among the 622 measured points, 62 (10.0%) were within restenotic areas; 560 (90.0%) were in arterial segments without proven angiographic restenosis. As far as source centering is concerned, 7.9% of restenotic points were observed when the maximum distance to the arterial wall was 5 mm. Conclusions: The proportion of restenotic points significantly increased with source non-centering. This observation was interpreted as being related to a decrease in dose at the target. When the maximum distance between the source and the vessel surface was >5 mm, the dose at the reference depth (2 mm into the vessel wall) decreased to values lower than 5 Gy

Forging technology for large nuclear pressure vessel parts

International Nuclear Information System (INIS)

Kakimoto, Hideki; Ikegami, Tomonori

2014-01-01

The increasing output of nuclear power generation calls for larger vessels for next-generation nuclear power plants. A vessel with an increased diameter requires increased load for its forging, which can make it difficult to use a conventional solid die. In order to reduce the forging load, a rotary incremental forging method has been applied to hot forging. This method includes pressing and rotating a material in an incremental manner such that a target shape is obtained. This study aimed at improving the accuracy of numerical simulation for the rotary incremental forging to reduce the load when forging large vessels. This has enabled the temperature of the material and flow stress to be precisely predicted; an example of this is reported in the paper. Specifically, the heat transfer coefficient to be used for the numerical simulation had been determined experimentally from a small-scale hot-forging. The reduction of the flow stress associated with incremental forging, had been deduced from a compression test, and the value was applied to the numerical simulation. A preform was designed on the basis of the above simulation to perform a 1/1 size scale experiment. A precision of better than 5% has been confirmed for the shape prediction. (author)

Utility of dark-lumen MR colonography for the assessment of extra-colonic organs

International Nuclear Information System (INIS)

Ajaj, Waleed; Goyen, Mathias; Ruehm, Stefan G.; Ladd, Susanne C.; Gerken, Guido

2007-01-01

The aim of the study was to evaluate the utility of dark-lumen MR colonography (MRC) for the assessment of extra-colonic organs. Three hundred seventy-five subjects with suspected colonic disease underwent a complete MRC examination. MRC data were evaluated by two radiologists in a blinded fashion. In addition to the large bowel, the extra-intestinal organs from the lung bases to the pelvis were assessed for the presence of pathologies. All findings were divided into known or unknown findings and therapeutically relevant or irrelevant findings. If deemed necessary, other diagnostic imaging tests to further assess those findings were performed. In total, 510 extra-colonic findings were found in 260 (69%) of the 375 subjects. Known extra-colonic findings were found in 140 subjects (54%) and unknown findings in 120 subjects (46%). Thirty-one (12%) of the 260 subjects had therapeutically relevant findings (45 findings); 229 patients (88%) had irrelevant findings (465 findings). Dark-lumen MRC is a useful tool not only for the assessment of the entire colon, but also for the evaluation of extra-colonic organs. Thus, intra- and extra-colonic pathologies can be diagnosed within the same examination. (orig.)

SAS-6 assembly templated by the lumen of cartwheel-less centrioles precedes centriole duplication.

Science.gov (United States)

Fong, Chii Shyang; Kim, Minhee; Yang, T Tony; Liao, Jung-Chi; Tsou, Meng-Fu Bryan

2014-07-28

Centrioles are 9-fold symmetric structures duplicating once per cell cycle. Duplication involves self-oligomerization of the centriolar protein SAS-6, but how the 9-fold symmetry is invariantly established remains unclear. Here, we found that SAS-6 assembly can be shaped by preexisting (or mother) centrioles. During S phase, SAS-6 molecules are first recruited to the proximal lumen of the mother centriole, adopting a cartwheel-like organization through interactions with the luminal wall, rather than via their self-oligomerization activity. The removal or release of luminal SAS-6 requires Plk4 and the cartwheel protein STIL. Abolishing either the recruitment or the removal of luminal SAS-6 hinders SAS-6 (or centriole) assembly at the outside wall of mother centrioles. After duplication, the lumen of engaged mother centrioles becomes inaccessible to SAS-6, correlating with a block for reduplication. These results lead to a proposed model that centrioles may duplicate via a template-based process to preserve their geometry and copy number. Copyright © 2014 Elsevier Inc. All rights reserved.

Assessment of lumen degradation and remaining useful life of LEDs using particle filter

Energy Technology Data Exchange (ETDEWEB)

Lall, Pradeep [Auburn Univ., AL (United States); Zhang, Hao [Auburn Univ., AL (United States); Davis, Lynn [Auburn Univ., AL (United States)

2013-07-16

With the development of light-emitting diode (LED) technology, light emitting diodes system is becoming a popular light source in daily life and industry area. It has shown that Led from same factory and work under same working condition, may have significantly different behavior. Therefore, it is very important to learn the fail mechanisms, especially in the case of safety critical and harsh environment application. This paper focus on a prognostic health management (PHM) method based on the measurement of forward voltage and forward current of bare LED under harsh environment. In this paper, experiment has been done with ten samples. Ten pristine bare LEDs have been tested at 85°C while simultaneously being subjected to 85% humid environment. Pulse width modulation (PWM) control method has been employed to drive the bare LED in order to reduce the heat effect caused by forward current and high frequency (300HZ) data acquisition has been used to measure the peak forward voltage and forward current. Test to failure (lumen drops to 70 percent) data has been measured to study the effects of high temperature and humid environment loadings on the bare LED. Also, solid state cooling method with peltier cooler has been used to control the temperature of LED in the integrating sphere when take the measurement of lumen flux. The shift of forward voltage forward current curve and lumen degradation has been recorded to help build the fail model and predicted the remaining useful life. In this method, particle filter has been employed to predict the remaining useful life (RUL) of the bare LED and give us a whole picture how Led system fails. Result shows that predication of remaining useful life of Led, made by the particle filter model works under reasonable limit, and hence this method can be employed to predict the failure of Led caused by thermal and humid stress under harsh environment.

Oscillation of Angiogenesis with Vascular Dropout in Diabetic Retinopathy by VESsel GENeration Analysis (VESGEN)

Science.gov (United States)

Parsons-Wingerter, Patricia; Radbakrishnan, Krisbnan; Vickerman, Mary B.; Kaiser, Peter K.

2010-01-01

PURPOSE. Vascular dropout and angiogenesis are hallmarks of the progression of diabetic retinopathy (DR). However, current evaluation of DR relies on grading of secondary vascular effects, such as microaneurysms and hemorrhages, by clinical examination instead of by evaluation of actual vascular changes. The purpose of this study was to map and quantify vascular changes during progression of DR by VESsel GENeration Analysis (VESGEN). METHODS. In this prospective cross-sectional study, 15 eyes with DR were evaluated with fluorescein angiography (FA) and color fundus photography, and were graded using modified Early Treatment Diabetic Retinopathy Study criteria. FA images were separated by semiautomatic image processing into arterial and venous trees. Vessel length density (L(sub v)), number density (N(sub v)), and diameter (D(sub v)) were analyzed in a masked fashion with VESGEN software. Each vascular tree was automatically segmented into branching generations (G(sub 1)...G(sub 8) or G(sub 9)) by vessel diameter and branching. Vascular remodeling status (VRS) for N(sub v) and L(sub v) was graded 1 to 4 for increasing severity of vascular change. RESULTS. By N(sub v) and L(sub v), VRS correlated significantly with the independent clinical diagnosis of mild to proliferative DR (13/15 eyes). N(sub v) and L(sub v) of smaller vessels (G(sub >=6) increased from VRS1 to VRS2 by 2.4 X and 1.6 X, decreased from VRS2 to VRS3 by 0.4 X and 0.6X, and increased from VRS3 to VRS4 by 1.7 X and 1.5 X (P dropout were dominated first by remodeling of arteries and subsequently by veins.

DIII-D in-vessel port cover and shutter assembly for the phase contrast interferometer

International Nuclear Information System (INIS)

Phelps, R.D.

1994-01-01

The entire outer wall of the DIII-D vacuum vessel interion is covered with a regular array of graphite tiles. Certain of the diagnostic ports through the outer vessel wall contain equipment which is shielded from the plasma by installing port covers designed to withstand energy deposition. If the diagnostic contained in the port must communicate with the vessel volume, a shutter assembly is usually provided. In the ports at 285 degrees, R+1 and R-1, interferometer mirrors have been installed to provide a means for transmitting a large diameter CO-2 laser beam through the edge of the plasma. To protect the mirrors and other hardware contained in these ports, a special protective plate and shutter arrangement has been designed. This report describes the details of design, fabrication, and installation of these protective covers and shutters

Microstructural evolution in reactor pressure vessel steel under neutron irradiation

Energy Technology Data Exchange (ETDEWEB)

Ohno, Katsumi; Fukuya, Koji [Institute of Nuclear Safety System Inc., Seika, Kyoto (Japan)

2000-09-01

Understanding microstructural changes in reactor pressure vessel steels is important in order to evaluate radiation-induced embrittlement, one of the major aging phenomena affecting the extension of plant life. In this study, actual surveillance test specimens and samples of rector vessel low-alloy steel (A533B steel) irradiated in a research reactor were examined using state-of-the-art techniques to clarify the neutron flux effect on the microstructural changes. These techniques included small angle neutron scattering and atom probes. Microstructural changes which are considered to be the main factors affecting embrittlement, including the production of copper-rich precipitates and the segregation of impurity elements, were confirmed by the results of the study. In addition, the mechanical properties were predicted based on the obtained quantitative data such as the diameters of precipitates. Consequently, the hardening due to irradiation was almost simulated. (author)

Primo vessel inside a lymph vessel emerging from a cancer tissue.

Science.gov (United States)

Lee, Sungwoo; Ryu, Yeonhee; Cha, Jinmyung; Lee, Jin-Kyu; Soh, Kwang-Sup; Kim, Sungchul; Lim, Jaekwan

2012-10-01

Primo vessels were observed inside the lymph vessels near the caudal vena cava of a rabbit and a rat and in the thoracic lymph duct of a mouse. In the current work we found a primo vessel inside the lymph vessel that came out from the tumor tissue of a mouse. A cancer model of a nude mouse was made with human lung cancer cell line NCI-H460. We injected fluorescent nanoparticles into the xenografted tumor tissue and studied their flow in blood, lymph, and primo vessels. Fluorescent nanoparticles flowed through the blood vessels quickly in few minutes, and but slowly in the lymph vessels. The bright fluorescent signals of nanoparticles disappeared within one hour in the blood vessels but remained much longer up to several hours in the case of lymph vessels. We found an exceptional case of lymph vessels that remained bright with fluorescence up to 24 hours. After detailed examination we found that the bright fluorescence was due to a putative primo vessel inside the lymph vessel. This rare observation is consistent with Bong-Han Kim's claim on the presence of a primo vascular system in lymph vessels. It provides a significant suggestion on the cancer metastasis through primo vessels and lymph vessels. Copyright © 2012. Published by Elsevier B.V.

Failure Diameter Resolution Study

Energy Technology Data Exchange (ETDEWEB)

Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-12-19

Previously the SURFplus reactive burn model was calibrated for the TATB based explosive PBX 9502. The calibration was based on fitting Pop plot data, the failure diameter and the limiting detonation speed, and curvature effect data for small curvature. The model failure diameter is determined utilizing 2-D simulations of an unconfined rate stick to find the minimum diameter for which a detonation wave propagates. Here we examine the effect of mesh resolution on an unconfined rate stick with a diameter (10mm) slightly greater than the measured failure diameter (8 to 9 mm).

Carbonic anhydrase inhibition increases retinal oxygen tension and dilates retinal vessels

DEFF Research Database (Denmark)

Pedersen, Daniella Bach; Koch Jensen, Peter; la Cour, Morten

2005-01-01

Carbonic anhydrase inhibitors (CAIs) increase blood flow in the brain and probably also in the optic nerve and retina. Additionally they elevate the oxygen tension in the optic nerve in the pig. We propose that they also raise the oxygen tension in the retina. We studied the oxygen tension in the...... in the pig retina and optic nerve before and after dorzolamide injection. Also the retinal vessel diameters during carbonic anhydrase inhibition were studied....

A novel Hsp70 of the yeast ER lumen is required for the efficient translocation of a number of protein precursors.

OpenAIRE

Craven, R A; Egerton, M; Stirling, C J

1996-01-01

The yeast genome sequencing project predicts an open reading frame (YKL073) that would encode a novel member of the Hsp70 family of molecular chaperones. We report that this 881 codon reading frame represents a functional gene expressing a 113-119 kDa glycoprotein localized within the lumen of the endoplasmic reticulum (ER). We therefore propose to designate this gene LHS1 (Lumenal Hsp Seventy). Our studies indicate that LHS1 is regulated by the unfolded protein response pathway, as evidenced...

High-resolution MRI vessel wall imaging: spatial and temporal patterns of reversible cerebral vasoconstriction syndrome and central nervous system vasculitis.

Science.gov (United States)

Obusez, E C; Hui, F; Hajj-Ali, R A; Cerejo, R; Calabrese, L H; Hammad, T; Jones, S E

2014-08-01

High-resolution MR imaging is an emerging tool for evaluating intracranial artery disease. It has an advantage of defining vessel wall characteristics of intracranial vascular diseases. We investigated high-resolution MR imaging arterial wall characteristics of CNS vasculitis and reversible cerebral vasoconstriction syndrome to determine wall pattern changes during a follow-up period. We retrospectively reviewed 3T-high-resolution MR imaging vessel wall studies performed on 26 patients with a confirmed diagnosis of CNS vasculitis and reversible cerebral vasoconstriction syndrome during a follow-up period. Vessel wall imaging protocol included black-blood contrast-enhanced T1-weighted sequences with fat suppression and a saturation band, and time-of-flight MRA of the circle of Willis. Vessel wall characteristics including enhancement, wall thickening, and lumen narrowing were collected. Thirteen patients with CNS vasculitis and 13 patients with reversible cerebral vasoconstriction syndrome were included. In the CNS vasculitis group, 9 patients showed smooth, concentric wall enhancement and thickening; 3 patients had smooth, eccentric wall enhancement and thickening; and 1 patient was without wall enhancement and thickening. Six of 13 patients had follow-up imaging; 4 patients showed stable smooth, concentric enhancement and thickening; and 2 patients had resoluton of initial imaging findings. In the reversible cerebral vasoconstriction syndrome group, 10 patients showed diffuse, uniform wall thickening with negligible-to-mild enhancement. Nine patients had follow-up imaging, with 8 patients showing complete resolution of the initial findings. Postgadolinium 3T-high-resolution MR imaging appears to be a feasible tool in differentiating vessel wall patterns of CNS vasculitis and reversible cerebral vasoconstriction syndrome changes during a follow-up period. © 2014 by American Journal of Neuroradiology.

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.

ICG-assisted blood vessel detection during stereotactic neurosurgery: simulation study on excitation power limitations due to thermal effects in human brain tissue.

Science.gov (United States)

Rühm, Adrian; Göbel, Werner; Sroka, Ronald; Stepp, Herbert

2014-09-01

Intraoperative blood vessel detection based on intraluminal indocyanin-green (ICG) would allow to minimize the risk of blood vessel perforation during stereotactic brain tumor biopsy. For a fiber-based approach compatible with clinical conditions, the maximum tolerable excitation light power was derived from simulations of the thermal heat load on the tissue. Using the simulation software LITCIT, the temperature distribution in human brain tissue was calculated as a function of time for realistic single-fiber probes (0.72mm active diameter, numerical aperture 0.35, optional focusing to 0.29mm diameter) and for the optimum ICG excitation wavelength of 785nm. The asymptotic maximum temperature in the simulated tissue region was derived for different radiant fluxes at the distal fiber end. Worst case values were assumed for all other parameters. In addition to homogeneous (normal and tumor) brain tissue with homogeneous blood perfusion, models with localized extra blood vessels incorporated ahead of the distal fiber end were investigated. If one demands that destruction of normal brain tissue must be excluded by limiting the tissue heating to 42°C, then the radiant flux at the distal fiber end must be limited to 33mW with and 43mW without focusing. When considering extra blood vessels of 0.1mm diameter incorporated into homogeneously perfused brain tissue, the tolerable radiant flux is reduced to 22mW with and 32mW without focusing. The threshold value according to legal laser safety regulations for human skin tissue is 28.5mW. For the envisaged modality of blood vessel detection, light power limits for an application-relevant fiber configuration were determined and found to be roughly consistent with present legal regulations for skin tissue. Copyright © 2014 Elsevier B.V. All rights reserved.

Tests of the geometrical description of blood vessels in a thermal model using counter-current geometries

NARCIS (Netherlands)

van Leeuwen, G. M.; Kotte, A. N.; Crezee, J.; Lagendijk, J. J.

1997-01-01

We have developed a thermal model, for use in hyperthermia treatment planning, in which blood vessels are described as geometrical objects; 3D curves with associated diameters. For the calculation of the heat exchange with the tissue an analytic result is used. To arrive at this result some

C - reactive protein and chitinase 3-like protein 1 as biomarkers of spatial redistribution of retinal blood vessels on digital retinal photography in patients with diabetic retinopathy

Directory of Open Access Journals (Sweden)

Sonja Predrag Cekic

2014-08-01

Full Text Available The aim of the study was to investegate the correlation between the levels of CRP and YKL-40 in blood samples with morphometric parameters of retinal blood vessels in patients with diabetic retinopathy.Blood laboratory examination of 90 patients included the measurement of glycemia, HbA1C, total cholesterol, LDL-C, HDL-C, triglycerides and CRP. Levels of YKL-40 were detected and measured in serum by ELISA (Micro VueYKL-40 EIA Kit, Quidel Corporation, San Diego, USA.Morphmetric analysis was performed with ImageJ software (http://rsbweb.nih.gov/ij/ for digital retinal photography. We measured the number, diameter of retinal blood vessels in five different parts concentric to the optic disc. Differences between the morphometric parameters and the blood test analysis results were evaluated using the Student’s t – test. One Way ANOVA was used to establish the significance of differences.CRP and YKL-40 levels were moderately higher in the group of patients with severe diabetic retinopathy. Levels of YKL-40 correlated positively with diameter and negatively with number of retinal blood vessels. The average number of the blood vessels per retinal zone was significantly higher in the group of patients with mild non-proliferative diabetic retinopathy than in the group with severe form in the optic disc and all five retinal zones. The average outer diameter of the evaluated retinal zones and optic disc vessels was significantly higher in the group with severe compared to the group with mild diabetic retinopathy.Morphological analysis of the retinal vessels on digital fundus photography and correlation with YKL-40 may be valuable for the follow-up of diabetic retinopathy.

Behavior of a corium jet in high pressure melt ejection from a reactor pressure vessel

International Nuclear Information System (INIS)

Frid, W.

1987-01-01

This report provides results from analytical and experimental investigations on the behavior of a gas supersaturated molten jet expelled from a pressurized vessel. Aero-hydrodynamic stability of liquid jets in gas, stream degassing of molten metals and gas bubble nucleation in molten metals are relevant problems which are addressed in this work. Models are developed for jet expansion, primary breakup of the jet and secondary fragmentation of melt droplets resulting from violent effervescence of dissolved gas. The jet expansion model is based on a general relation for bubble growth which includes both inertia-controlled and diffusion-controlled growth phases. The jet expansion model is able to predict the jet void fraction, jet radius as a function of axial distance from the pressure vessel, bubble size and bubble pressure. The number density of gas bubbles in the melt, which is a basic parameter in the model, was determined experimentally and is about 10 8 per m 3 of liquid. The primary breakup of the jet produces a spray of droplets, about 2-3 mm in diameter. Parametric calculations for a TMLB' reactor accident sequence show that the corium jet is disrupted within a few initial jet diameters from the reactor vessel and that the radius of corium spray at the level of the reactor cavity floor is in the range of 0.8 to 2.6 m. (orig./HP)

CT and histopathologic characteristics of lung adenocarcinoma with pure ground-glass nodules 10 mm or less in diameter

Energy Technology Data Exchange (ETDEWEB)

Wu, Fang [Chinese PLA General Hospital, Department of Radiology, Beijing (China); Capital Medical University, Department of Radiology, Xuanwu Hospital, Beijing (China); Tian, Shu-ping [Navy General Hospital, Department of Radiology, Beijing (China); Jin, Xin; Jing, Rui; Yang, Yue-qing; Jin, Mei; Zhao, Shao-hong [Chinese PLA General Hospital, Department of Radiology, Beijing (China)

2017-10-15

To evaluate CT and histopathologic features of lung adenocarcinoma with pure ground-glass nodule (pGGN) ≤10 mm in diameter. CT appearances of 148 patients (150 lesions) who underwent curative resection of lung adenocarcinoma with pGGN ≤10 mm (25 atypical adenomatous hyperplasias, 42 adenocarcinoma in situs, 38 minimally invasive adenocarcinomas, and 45 invasive pulmonary adenocarcinomas) were analyzed for lesion size, density, bubble-like sign, air bronchogram, vessel changes, margin, and tumour-lung interface. CT characteristics were compared among different histopathologic subtypes. Univariate and multivariate analysis were used to assess the relationship between CT characteristics of pGGN and lesion invasiveness, respectively. There were statistically significant differences among histopathologic subtypes in lesion size, vessel changes, and tumour-lung interface (P<0.05). Univariate analysis revealed significant differences of vessel changes, margin and tumour-lung interface between preinvasive and invasive lesions (P<0.05). Logistic regression analysis showed that the vessel changes, unsmooth margin and clear tumour-lung interface were significant predictive factors for lesion invasiveness, with odds ratios (95% CI) of 2.57 (1.17-5.62), 1.83 (1.25-2.68) and 4.25 (1.78-10.14), respectively. Invasive lesions are found in 55.3% of subcentimeter pGGNs in our cohort. Vessel changes, unsmooth margin, and clear lung-tumour interface may indicate the invasiveness of lung adenocarcinoma with subcentimeter pGGN. (orig.)

Integration of multi-modality imaging for accurate 3D reconstruction of human coronary arteries in vivo

International Nuclear Information System (INIS)

Giannoglou, George D.; Chatzizisis, Yiannis S.; Sianos, George; Tsikaderis, Dimitrios; Matakos, Antonis; Koutkias, Vassilios; Diamantopoulos, Panagiotis; Maglaveras, Nicos; Parcharidis, George E.; Louridas, George E.

2006-01-01

In conventional intravascular ultrasound (IVUS)-based three-dimensional (3D) reconstruction of human coronary arteries, IVUS images are arranged linearly generating a straight vessel volume. However, with this approach real vessel curvature is neglected. To overcome this limitation an imaging method was developed based on integration of IVUS and biplane coronary angiography (BCA). In 17 coronary arteries from nine patients, IVUS and BCA were performed. From each angiographic projection, a single end-diastolic frame was selected and in each frame the IVUS catheter was interactively detected for the extraction of 3D catheter path. Ultrasound data was obtained with a sheath-based catheter and recorded on S-VHS videotape. S-VHS data was digitized and lumen and media-adventitia contours were semi-automatically detected in end-diastolic IVUS images. Each pair of contours was aligned perpendicularly to the catheter path and rotated in space by implementing an algorithm based on Frenet-Serret rules. Lumen and media-adventitia contours were interpolated through generation of intermediate contours creating a real 3D lumen and vessel volume, respectively. The absolute orientation of the reconstructed lumen was determined by back-projecting it onto both angiographic planes and comparing the projected lumen with the actual angiographic lumen. In conclusion, our method is capable of performing rapid and accurate 3D reconstruction of human coronary arteries in vivo. This technique can be utilized for reliable plaque morphometric, geometrical and hemodynamic analyses

C-reactive protein and chitinase 3-like protein 1 as biomarkers of spatial redistribution of retinal blood vessels on digital retinal photography in patients with diabetic retinopathy.

Science.gov (United States)

Cekić, Sonja; Cvetković, Tatjana; Jovanović, Ivan; Jovanović, Predrag; Pesić, Milica; Stanković Babić, Gordana; Milenković, Svetislav; Risimić, Dijana

2014-08-20

The aim of the study was to investigate the correlation between the levels of C-reactive protein (CRP) and chitinase 3-like protein 1 (YKL-40) in blood samples with morpohometric parameters of retinal blood vessels in patients with diabetic retinopathy. Blood laboratory examination of 90 patients included the measurement of glycemia, HbA1C, total cholesterol, LDL-C, HDL-C, triglycerides and CRP. Levels of YKL-40 were detected and measured in serum by ELISA (Micro VueYKL-40 EIA Kit, Quidel Corporation, San Diego, USA). YKL-40 correlated positively with diameter and negatively with number of retinal blood vessels. The average number of the blood vessels per retinal zone was significantly higher in the group of patients with mild non-proliferative diabetic retinopathy than in the group with severe form in the optic disc and all five retinal zones. The average outer diameter of the evaluated retinal zones and optic disc vessels was significantly higher in the group with severe compared to the group with mild diabetic retinopathy. Morphological analysis of the retinal vessels on digital fundus photography and correlation with YKL-40 may be valuable for the follow-up of diabetic retinopathy.

Flash-flood impacts cause changes in wood anatomy of Alnus glutinosa, Fraxinus angustifolia and Quercus pyrenaica.

Science.gov (United States)

Ballesteros, J A; Stoffel, M; Bollschweiler, M; Bodoque, J M; Díez-Herrero, A

2010-06-01

Flash floods may influence the development of trees growing on channel bars and floodplains. In this study, we analyze and quantify anatomical reactions to wounding in diffuse-porous (Alnus glutinosa L.) and ring-porous (Fraxinus angustifolia Vahl. and Quercus pyrenaica Willd.) trees in a Mediterranean environment. A total of 54 cross-sections and wedges were collected from trees that had been injured by past flash floods. From each of the samples, micro-sections were prepared at a tangential distance of 1.5 cm from the injury to determine wounding-related changes in radial width, tangential width and lumen of earlywood vessels, and fibers and parenchyma cells (FPC). In diffuse-porous A. glutinosa, the lumen area of vessels shows a significant (non-parametric test, P-value <0.05) decrease by almost 39% after wounding. For ring-porous F. angustifolia and Q. pyrenaica, significant decreases in vessel lumen area are observed as well by 59 and 42%, respectively. Radial width of vessels was generally more sensitive to the decrease than tangential width, but statistically significant values were only observed in F. angustifolia. Changes in the dimensions of earlywood FPC largely differed between species. While in ring-porous F. angustifolia and Q. pyrenaica the lumen of FPC dropped by 22 and 34% after wounding, we observed an increase in FPC lumen area in diffuse-porous A. glutinosa of approximately 35%. Our data clearly show that A. glutinosa represents a valuable species for flash-flood research in vulnerable Mediterranean environments. For this species, it will be possible in the future to gather information on past flash floods with non-destructive sampling based on increment cores. In ring-porous F. angustifolia and Q. pyrenaica, flash floods leave less drastic, yet still recognizable, signatures of flash-flood activity through significant changes in vessel lumen area. In contrast, the use of changes in FPC dimensions appears less feasible for the determination of

Comparison of coronary arterial lumen dimensions on angiography and plaque characteristics on optical coherence tomography images and their changes induced by statin

International Nuclear Information System (INIS)

Dong, Nana; Xie, Zulong; Wang, Wei; Dai, Jiannan; Sun, Meng; Pu, Zhongyue; Tian, Jinwei; Yu, Bo

2016-01-01

Coronary angiography (CAG) is widely used to assess lumen dimensions, and optical coherence tomography (OCT) is used to evaluate the characteristics of atherosclerotic plaque. This study was aimed to compare coronary lumen dimensions using CAG and plaque characteristics using OCT and their changes during statin therapy. We identified 97 lipid-rich plaques from 69 statin-naïve patients, who received statin therapy in the following 12 months. CAG and OCT examinations were conducted at baseline and 12-month follow-up period. Lesion length, as measured by CAG, was closely correlated with lipid length by OCT (baseline: r = 0.754, p < 0.001; follow-up: r = 0.639, p < 0.001). However, no significant correlations were found between the other findings on OCT and data on CAG. With 12-month statin therapy, microstructures of lipid-rich plaques were significantly improved, but CAG-derived lumen dimensions were not improved. Moreover, we found no significant relationship between changes in OCT measurements and changes in CAG data over time. Lipid length on OCT and lesion length on CAG were closely correlated. However, plaque microstructural characteristics on OCT showed no significantly statistically correlations with lumen dimensions on CAG, neither did their evolutionary changes induced by statin over time. Clinical trial registry: ClinicalTrial.gov. Registered number: NCT01023607. Registered 1 December 2009

Demonstration tests for manufacturing the ITER vacuum vessel

International Nuclear Information System (INIS)

Shimizu, Katsusuke; Onozuka, Masanori; Usui, Yukinori; Urata, Kazuhiro; Tsujita, Yoshihiro; Nakahira, Masataka; Takeda, Nobukazu; Kakudate, Satoshi; Ohmori, Junji; Shibanuma, Kiyoshi

2007-01-01

Demonstration tests for manufacturing and assembly of the International Thermonuclear Experimental Reactor (ITER) vacuum vessel have been conducted to confirm manufacturing and assembly process of the vacuum vessel (VV). The full-scale partial mock-up fabrication was planned and is in progress. The results will be available in the near future. Field-joint assembly procedure has been demonstrated using a test stand. Due to limited accessibility to the outer shell at the field joint, some operations, including alignment of the splice plates, field-joint welding, and examination, were found to be very difficult. In addition, a demonstration test on the selected back-seal structures was performed. It was found that the tested structures have insufficient sealing capabilities and need further improvement. The applicability of ultrasonic testing methods has been investigated. Although side drilled holes of 2.4 mm in diameter were detected, detection of the slit-type defects and defect characterization were found to be difficult. Feasibility test of liquid penetrant testing has revealed that the selected liquid penetrant testing (LPT) solutions have sufficient low outgas rates and are applicable to the VV

Demonstration tests for manufacturing the ITER vacuum vessel

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Katsusuke [Mitsubishi Heavy Industries, Ltd., Kobe Shipyard and Machinery Works, Wadasaki-cho 1-1-1, Hyogo-ku, Kobe 652-8585 (Japan)], E-mail: katsusuke_shimizu@mhi.co.jp; Onozuka, Masanori [Mitsubishi Heavy Industries, Ltd., Konan 2-16-5, Minato-ku, Tokyo 108-8215 (Japan); Usui, Yukinori; Urata, Kazuhiro; Tsujita, Yoshihiro [Mitsubishi Heavy Industries, Ltd., Kobe Shipyard and Machinery Works, Wadasaki-cho 1-1-1, Hyogo-ku, Kobe 652-8585 (Japan); Nakahira, Masataka; Takeda, Nobukazu; Kakudate, Satoshi; Ohmori, Junji; Shibanuma, Kiyoshi [Japan Atomic Energy Agency, Mukouyama 801-1, Naka-machi, Naka-gun, Ibaraki 311-0193 (Japan)

2007-10-15

Demonstration tests for manufacturing and assembly of the International Thermonuclear Experimental Reactor (ITER) vacuum vessel have been conducted to confirm manufacturing and assembly process of the vacuum vessel (VV). The full-scale partial mock-up fabrication was planned and is in progress. The results will be available in the near future. Field-joint assembly procedure has been demonstrated using a test stand. Due to limited accessibility to the outer shell at the field joint, some operations, including alignment of the splice plates, field-joint welding, and examination, were found to be very difficult. In addition, a demonstration test on the selected back-seal structures was performed. It was found that the tested structures have insufficient sealing capabilities and need further improvement. The applicability of ultrasonic testing methods has been investigated. Although side drilled holes of 2.4 mm in diameter were detected, detection of the slit-type defects and defect characterization were found to be difficult. Feasibility test of liquid penetrant testing has revealed that the selected liquid penetrant testing (LPT) solutions have sufficient low outgas rates and are applicable to the VV.

Instability of Reference Diameter in the Evaluation of Stenosis After Coronary Angioplasty: Percent Diameter Stenosis Overestimates Dilative Effects Due to Reference Diameter Reduction

International Nuclear Information System (INIS)

Hirami, Ryouichi; Iwasaki, Kohichiro; Kusachi, Shozo; Murakami, Takashi; Hina, Kazuyoshi; Matano, Shigeru; Murakami, Masaaki; Kita, Toshimasa; Sakakibara, Noburu; Tsuji, Takao

2000-01-01

Purpose: To examine changes in the reference segment luminal diameter after coronary angioplasty.Methods: Sixty-one patients with stable angina pectoris or old myocardial infarction were examined. Coronary angiograms were recorded before coronary angioplasty (pre-angioplasty) and immediately after (post-angioplasty), as well as 3 months after. Artery diameters were measured on cine-film using quantitative coronary angiographic analysis.Results: The diameters of the proximal segment not involved in the balloon inflation and segments in the other artery did not change significantly after angioplasty, but the reference segment diameter significantly decreased (4.7%). More than 10% luminal reduction was observed in seven patients (11%) and more than 5% reduction was observed in 25 patients (41%). More than 5% underestimation of the stenosis was observed in 22 patients (36%) when the post-angioplasty reference diameter was used as the reference diameter, compared with when the pre-angioplasty measurement was used and more than 10% underestimation was observed in five patients (8%).Conclusion: This study indicated that evaluation by percent diameter stenosis, with the reference diameter from immediately after angioplasty, overestimates the dilative effects of coronary angioplasty, and that it is thus better to evaluate the efficacy of angioplasty using the absolute diameter in addition to percent luminal stenosis

Integration of vessel traits, wood density, and height in angiosperm shrubs and trees.

Science.gov (United States)

Martínez-Cabrera, Hugo I; Schenk, H Jochen; Cevallos-Ferriz, Sergio R S; Jones, Cynthia S

2011-05-01

Trees and shrubs tend to occupy different niches within and across ecosystems; therefore, traits related to their resource use and life history are expected to differ. Here we analyzed how growth form is related to variation in integration among vessel traits, wood density, and height. We also considered the ecological and evolutionary consequences of such differences. In a sample of 200 woody plant species (65 shrubs and 135 trees) from Argentina, Mexico, and the United States, standardized major axis (SMA) regression, correlation analyses, and ANOVA were used to determine whether relationships among traits differed between growth forms. The influence of phylogenetic relationships was examined with a phylogenetic ANOVA and phylogenetically independent contrasts (PICs). A principal component analysis was conducted to determine whether trees and shrubs occupy different portions of multivariate trait space. Wood density did not differ between shrubs and trees, but there were significant differences in vessel diameter, vessel density, theoretical conductivity, and as expected, height. In addition, relationships between vessel traits and wood density differed between growth forms. Trees showed coordination among vessel traits, wood density, and height, but in shrubs, wood density and vessel traits were independent. These results hold when phylogenetic relationships were considered. In the multivariate analyses, these differences translated as significantly different positions in multivariate trait space occupied by shrubs and trees. Differences in trait integration between growth forms suggest that evolution of growth form in some lineages might be associated with the degree of trait interrelation.

Optics based signal processing methods for intraoperative blood vessel detection and quantification in real time (Conference Presentation)

Science.gov (United States)

Chaturvedi, Amal; Shukair, Shetha A.; Le Rolland, Paul; Vijayvergia, Mayank; Subramanian, Hariharan; Gunn, Jonathan W.

2016-03-01

Minimally invasive operations require surgeons to make difficult cuts to blood vessels and other tissues with impaired tactile and visual feedback. This leads to inadvertent cuts to blood vessels hidden beneath tissue, causing serious health risks to patients and a non-reimbursable financial burden to hospitals. Intraoperative imaging technologies have been developed, but these expensive systems can be cumbersome and provide only a high-level view of blood vessel networks. In this research, we propose a lean reflectance-based system, comprised of a dual wavelength LED, photodiode, and novel signal processing algorithms for rapid vessel characterization. Since this system takes advantage of the inherent pulsatile light absorption characteristics of blood vessels, no contrast agent is required for its ability to detect the presence of a blood vessel buried deep inside any tissue type (up to a cm) in real time. Once a vessel is detected, the system is able to estimate the distance of the vessel from the probe and the diameter size of the vessel (with a resolution of ~2mm), as well as delineate the type of tissue surrounding the vessel. The system is low-cost, functions in real-time, and could be mounted on already existing surgical tools, such as Kittner dissectors or laparoscopic suction irrigation cannulae. Having been successfully validated ex vivo, this technology will next be tested in a live porcine study and eventually in clinical trials.

CALiPER Retail Lamps Study RRL3.2 Lumen and Chromaticity Maintenance of LED A lamps Operated in Steady-State Conditions

Energy Technology Data Exchange (ETDEWEB)

Royer, Michael P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McCullough, Jeffrey J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tucker, Joseph C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-12-01

The lumen depreciation and color shift of 17 different A lamps (15 LED, 1 CFL, 1 halogen) was monitored in the automated long-term test apparatus (ALTA) for more than 7,500 hours. Ten samples of each lamp model were tested, with measurements recorded on a weekly basis. The lamps were operated continuously at an ambient temperature of 45°C (-1°C). Importantly, the steady-state test conditions were not optimized for inducing catastrophic failure for any of the lamp technologies—to which thermal cycling is a strong contributor— and are not typical of normal use patterns—which usually include off periods where the lamp cools down. Further, the test conditions differ from those used in standardized long-term test methods (i.e., IES LM-80, IES LM-84), so the results should not be directly compared. On the other hand, the test conditions are similar to those used by ENERGY STAR (when elevated temperature testing is called for). Likewise, the conditions and assumptions used by manufacturers to generated lifetime claims may vary; the CALiPER long-term data is informative, but cannot necessarily be used to discredit manufacturer claims. The test method used for this investigation should be interpreted as one more focused on the long-term effects of elevated temperature operation, at an ambient temperature that is not uncommon in luminaires. On average, the lumen maintenance of the LED lamps monitored in the ALTA was better than benchmark lamps, but there was considerable variation from lamp model to lamp model. While three lamp models had average lumen maintenance above 99% at the end of the study period, two products had average lumen maintenance below 65%, constituting a parametric failure. These two products, along with a third, also exhibited substantial color shift, another form of parametric failure. While none of the LED lamps exhibited catastrophic failure—and all of the benchmarks did—the early degradation of performance is concerning, especially with a

Rates of chemical reaction and atmospheric heating during core debris expulsion from a pressurized vessel

International Nuclear Information System (INIS)

Powers, D.A.; Tarbell, W.W.; Brockman, J.E.; Pilch, M.

1986-01-01

Core debris may be expelled from a pressurized reactor vessel during a severe nuclear reactor accident. Experimental studies of core debris expulsion from pressurized vessels have established that the expelled material can be lofted into the atmosphere of the reactor containment as particulate 0.4 to 2 mm in diameter. These particles will vigorously react with steam and oxygen in the containment atmosphere. Data on such reactions during tests with 80 kg of expelled melt will be reported. A model of the reaction rates based on gas phase mass transport will be described and shown to account for atmospheric heating and aerosol generation observed in the tests

Proteomics of the chloroplast: systematic identification and targeting analysis of lumenal and peripheral thylakoid proteins

DEFF Research Database (Denmark)

Peltier, J B; Friso, G; Kalume, D E

2000-01-01

The soluble and peripheral proteins in the thylakoids of pea were systematically analyzed by using two-dimensional electrophoresis, mass spectrometry, and N-terminal Edman sequencing, followed by database searching. After correcting to eliminate possible isoforms and post-translational modificati......The soluble and peripheral proteins in the thylakoids of pea were systematically analyzed by using two-dimensional electrophoresis, mass spectrometry, and N-terminal Edman sequencing, followed by database searching. After correcting to eliminate possible isoforms and post......-translational modifications, we estimated that there are at least 200 to 230 different lumenal and peripheral proteins. Sixty-one proteins were identified; for 33 of these proteins, a clear function or functional domain could be identified, whereas for 10 proteins, no function could be assigned. For 18 proteins, no expressed...... sequence tag or full-length gene could be identified in the databases, despite experimental determination of a significant amount of amino acid sequence. Nine previously unidentified proteins with lumenal transit peptides are presented along with their full-length genes; seven of these proteins possess...

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

Accuracy and initial clinical experience with measurement software (advanced vessel analysis) in three-dimensional imaging

International Nuclear Information System (INIS)

Abe, Toshi; Hirohata, Masaru; Tanigawa, Hitoshi

2002-01-01

Recently, the clinical benefits of three dimensional (3D) imaging, such as 3D-CTA and 3D-DSA, in cerebro-vascular disease have been widely recognized. Software for quantitative analysis of vascular structure in 3D imaging (advanced vessel analysis: AVA) has been developed. We evaluated AVA with both phantom studies and a few clinical cases. In spiral and curvy aluminum tube phantom studies, the accuracy of diameter measurements was good in 3D images produced from data set generated by multi-detector row CT or rotational angiography. The measurement error was less than 0.03 mm on aluminum tube phantoms that were 3 mm and 5 mm in diameter. In the clinical studies, the differences of carotid artery diameter measurements between 2D-DSA and 3D-DSA was less than 0.3 mm in. The measurement of length, diameter and angle by AVA should provide useful information for planning surgical and endovascular treatments of cerebro-vascular disease. (author)

Impact of Chronic Rheumatic Valve Diseases on Large Vessels.

Science.gov (United States)

Altunbas, Gokhan; Yuce, Murat; Ozer, Hasan O; Davutoglu, Vedat; Ercan, Suleyman; Kizilkan, Nese; Bilici, Muhammet

2016-01-01

BACKGROUND AND AIM OF STUDY: Rheumatic valvular heart disease, which remains a common health problem in developing countries, has numerous consequences on the heart chambers and circulation. The study aim was to investigate the effects of chronic rheumatic valve disease on the diameters of the descending aorta (DA) and inferior vena cava (IVC). METHODS: A total of 88 patients with echocardiographically documented rheumatic valvular heart disease and 112 healthy controls were enrolled into the study. All patients underwent detailed echocardiographic examinations, while their height and body weight were recorded and adjusted to their body surface area. RESULTS: The most common involvement was mitral valve disease, followed by aortic valve disease and tricuspid valve disease. The mean diameter of the DA (indexed to BSA) was 1.79 ± 0.49 cm for patients and 1.53 ± 0.41 for controls (p Rheumatic valve disease, especially mitral stenosis, was closely related to remodeling of the great vessels.

Prediction of Lumen Output and Chromaticity Shift in LEDs Using Kalman Filter and Extended Kalman Filter Based Models

Energy Technology Data Exchange (ETDEWEB)

Lall, Pradeep; Wei, Junchao; Davis, J Lynn

2014-06-24

Abstract— Solid-state lighting (SSL) luminaires containing light emitting diodes (LEDs) have the potential of seeing excessive temperatures when being transported across country or being stored in non-climate controlled warehouses. They are also being used in outdoor applications in desert environments that see little or no humidity but will experience extremely high temperatures during the day. This makes it important to increase our understanding of what effects high temperature exposure for a prolonged period of time will have on the usability and survivability of these devices. Traditional light sources “burn out” at end-of-life. For an incandescent bulb, the lamp life is defined by B50 life. However, the LEDs have no filament to “burn”. The LEDs continually degrade and the light output decreases eventually below useful levels causing failure. Presently, the TM-21 test standard is used to predict the L70 life of LEDs from LM-80 test data. Several failure mechanisms may be active in a LED at a single time causing lumen depreciation. The underlying TM-21 Model may not capture the failure physics in presence of multiple failure mechanisms. Correlation of lumen maintenance with underlying physics of degradation at system-level is needed. In this paper, Kalman Filter (KF) and Extended Kalman Filters (EKF) have been used to develop a 70-percent Lumen Maintenance Life Prediction Model for LEDs used in SSL luminaires. Ten-thousand hour LM-80 test data for various LEDs have been used for model development. System state at each future time has been computed based on the state space at preceding time step, system dynamics matrix, control vector, control matrix, measurement matrix, measured vector, process noise and measurement noise. The future state of the lumen depreciation has been estimated based on a second order Kalman Filter model and a Bayesian Framework. Life prediction of L70 life for the LEDs used in SSL luminaires from KF and EKF based models have

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.

Blood vessel classification into arteries and veins in retinal images

Science.gov (United States)

Kondermann, Claudia; Kondermann, Daniel; Yan, Michelle

2007-03-01

The prevalence of diabetes is expected to increase dramatically in coming years; already today it accounts for a major proportion of the health care budget in many countries. Diabetic Retinopathy (DR), a micro vascular complication very often seen in diabetes patients, is the most common cause of visual loss in working age population of developed countries today. Since the possibility of slowing or even stopping the progress of this disease depends on the early detection of DR, an automatic analysis of fundus images would be of great help to the ophthalmologist due to the small size of the symptoms and the large number of patients. An important symptom for DR are abnormally wide veins leading to an unusually low ratio of the average diameter of arteries to veins (AVR). There are also other diseases like high blood pressure or diseases of the pancreas with one symptom being an abnormal AVR value. To determine it, a classification of vessels as arteries or veins is indispensable. As to our knowledge despite the importance there have only been two approaches to vessel classification yet. Therefore we propose an improved method. We compare two feature extraction methods and two classification methods based on support vector machines and neural networks. Given a hand-segmentation of vessels our approach achieves 95.32% correctly classified vessel pixels. This value decreases by 10% on average, if the result of a segmentation algorithm is used as basis for the classification.

Evaluation for In-Vessel Retention Capabilities with In-Vessel Injection and External Reactor Vessel Cooling

International Nuclear Information System (INIS)

Lee, Jeong Seong; Ryu, In Chul; Moon, Young Tae

2016-01-01

If the accident has not progressed to the point of substantial changes in the core geometry, establishing adequate cooling is as straightforward as re-establishing flow through the reactor core. However, if the accident has progressed to the point where the core geometry is substantially altered as a result of material melting and relocation, as was the case in the TMI-2 accident, the means of cooling the debris are not as straightforward. From this time on, the reactor core was either completely or nearly covered by water, with high pressure injection flow initiated shortly after three hours into the accident. However, the core debris was not coolable in this configuration and a substantial quantity of molten core material drained into the bypass region, with approximately twenty metric tons of molten debris draining into the reactor pressure vessel (RPV) lower head. Hence, the core configuration developed at approximately three hours into the accident was not coolable, even submerged in water. The purpose of this paper is to evaluate in-vessel retention capabilities with in-vessel injection (IVI) and external reactor vessel cooling (ERVC) available in a reactor application by using the integrated severe accident analysis code. The MAAP5 models were improved to facilitate evaluation of the in-vessel retention capability of APR1400. In-vessel retention capabilities have been analyzed for the APR1400 using the MAAP5.03 code. The results show that in-vessel retention is feasible when in-vessel injection is initiated within a relatively short time frame under the simulation condition used in the present study

Evaluation for In-Vessel Retention Capabilities with In-Vessel Injection and External Reactor Vessel Cooling

Energy Technology Data Exchange (ETDEWEB)

Lee, Jeong Seong; Ryu, In Chul; Moon, Young Tae [KEPCO Engineering and Construction Co. Ltd., Deajeon (Korea, Republic of)

2016-10-15

If the accident has not progressed to the point of substantial changes in the core geometry, establishing adequate cooling is as straightforward as re-establishing flow through the reactor core. However, if the accident has progressed to the point where the core geometry is substantially altered as a result of material melting and relocation, as was the case in the TMI-2 accident, the means of cooling the debris are not as straightforward. From this time on, the reactor core was either completely or nearly covered by water, with high pressure injection flow initiated shortly after three hours into the accident. However, the core debris was not coolable in this configuration and a substantial quantity of molten core material drained into the bypass region, with approximately twenty metric tons of molten debris draining into the reactor pressure vessel (RPV) lower head. Hence, the core configuration developed at approximately three hours into the accident was not coolable, even submerged in water. The purpose of this paper is to evaluate in-vessel retention capabilities with in-vessel injection (IVI) and external reactor vessel cooling (ERVC) available in a reactor application by using the integrated severe accident analysis code. The MAAP5 models were improved to facilitate evaluation of the in-vessel retention capability of APR1400. In-vessel retention capabilities have been analyzed for the APR1400 using the MAAP5.03 code. The results show that in-vessel retention is feasible when in-vessel injection is initiated within a relatively short time frame under the simulation condition used in the present study.

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.

Contrasting xylem vessel constraints on hydraulic conductivity between native and non-native woody understory species

Directory of Open Access Journals (Sweden)

Maria S Smith

2013-11-01

Full Text Available We examined the hydraulic properties of 82 native and non-native woody species common to forests of Eastern North America, including several congeneric groups, representing a range of anatomical wood types. We observed smaller conduit diameters with greater frequency in non-native species, corresponding to lower calculated potential vulnerability to cavitation index. Non-native species exhibited higher vessel-grouping in metaxylem compared with native species, however, solitary vessels were more prevalent in secondary xylem. Higher frequency of solitary vessels in secondary xylem was related to a lower potential vulnerability index. We found no relationship between anatomical characteristics of xylem, origin of species and hydraulic conductivity, indicating that non-native species did not exhibit advantageous hydraulic efficiency over native species. Our results confer anatomical advantages for non-native species under the potential for cavitation due to freezing, perhaps permitting extended growing seasons.

FOREVER Experiments on Thermal and Mechanical Behavior of a Reactor Pressure Vessel during a Severe Accident

International Nuclear Information System (INIS)

Sehgal, B.R.; Nourgaliev, R.R.; Dinh, T.N.; Karbojian, A.; Green, J.A.; Bui, V.A.

1999-01-01

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 facility employs 1/10.-scale carbon steel vessels of 0.4 m diameter, 15 mm thickness and 600 mm height. Up to 20 liters of binary-oxide melts with 100-300 K superheat are employed, as a simulant for the prototypic corium melt, and internal heating is provided by electrical heaters of up to 20 kW power in order to maintain the vessel wall temperatures at 1100-1200 K. Auxiliary systems are designed to provide an overpressure up to 4 MPa in the test vessel. Thus, severe accident scenarios with RCS depressurization are modeled. Creep behavior of the three-dimensional vessel, formation of the gap between the melt pool crust and the creeping vessel, and mechanisms of the gap cooling by water ingression will be the subjects of study and measurements in the FOREVER experimental program. Scaling rationale as well as pre-test analyses of the thermal and mechanical behavior of the FOREVER test vessels are presented. (authors)

Multiple shell pressure vessel

International Nuclear Information System (INIS)

Wedellsborg, B.W.

1988-01-01

A method is described of fabricating a pressure vessel comprising the steps of: attaching a first inner pressure vessel having means defining inlet and outlet openings to a top flange, placing a second inner pressure vessel, having means defining inlet and outlet opening, concentric with and spaced about the first inner pressure vessel and attaching the second inner pressure vessel to the top flange, placing an outer pressure vessel, having inlet and outlet openings, concentric with and spaced apart about the second inner pressure vessel and attaching the outer pressure vessel to the top flange, attaching a generally cylindrical inner inlet conduit and a generally cylindrical inner outlet conduit respectively to the inlet and outlet openings in the first inner pressure vessel, attaching a generally cylindrical outer inlet conduit and a generally cylindrical outer outlet conduit respectively to the inlet and outlet opening in the second inner pressure vessel, heating the assembled pressure vessel to a temperature above the melting point of a material selected from the group, lead, tin, antimony, bismuth, potassium, sodium, boron and mixtures thereof, filling the space between the first inner pressure vessel and the second inner pressure vessel with material selected from the group, filling the space between the second inner pressure vessel and the outer pressure vessel with material selected from the group, and pressurizing the material filling the spaces between the pressure vessels to a predetermined pressure, the step comprising: pressurizing the spaces to a pressure whereby the wall of the first inner pressure vessel is maintained in compression during steady state operation of the pressure vessel

Cracking at nozzle corners in the nuclear pressure vessel industry

International Nuclear Information System (INIS)

Smith, C.W.

1986-01-01

Cracks in nozzle corners at the pressure boundary of nuclear reactors have been frequently observed in service. These cracks tend to form with radial orientations with respect to the nozzle central axis and are believed to be initiated by thermal shock. However, their growth is believed to be primarily due to a steady plus a fluctuating internal pressure. Due to the impracticality of fracture testing of full-scale models, the Oak Ridge National Laboratory instituted the use of an intermediate test vessel (ITV) for use in fracture testing which had the same wall thickness and nozzle size as the prototype but significantly reduced overall length and diameter. In order to determine whether or not these ITVs could provide realistic data for full-scale reactor vessels, laboratory models of full-scale boiling water reactors and ITVs were constructed and tested. After briefly reviewing the laboratory testing and correlating results with service experience, results obtained will be used to draw some general conclusions regarding the stable growth of nonplanar cracks with curved crack fronts which are the most common precursors to fracture of pressure vessel components near junctures. Use of linear elastic fracture mechanics is made in determining stress-intensity distribution along the crack fronts

Comparison between two-dimensional and three-dimensional quantitative coronary angiography for the prediction of functional severity in true bifurcation lesions: Insights from the randomized DK-CRUSH II, III, and IV trials.

Science.gov (United States)

Zhang, Yao-Jun; Zhu, Hao; Shi, Shun-Yi; Muramatsu, Takashi; Pan, Dao-Rong; Ye, Fei; Zhang, Jun-Jie; Tian, Nai-Liang; Bourantas, Christos V; Chen, Shao-Liang

2016-03-01

This study investigated the diagnostic accuracy of three-dimensional quantitative coronary angiography (3D-QCA) compared with conventional 2D-QCA for predicting functional severity assessed by fractional flow reserve (FFR) for true bifurcation lesions. Based on pooled data from the randomized DK-CRUSH II, III, and IV trials, we evaluated the patients with true bifurcation lesions who underwent coronary angiography together with functional evaluations using FFR in both the main vessel and the side branch. Off-line 2D- and 3D-QCA analyses were conducted using dedicated bifurcation QCA analysis software. Measurements of minimum lumen diameter (MLD), percentage diameter stenosis (% DS), and minimum lumen area (MLA) were compared between 2D- and 3D-QCA, and we evaluated their predictive values of functionally significant FFR. Ninety patients were eligible for enrollment in the present study. In the main vessel, MLA measured by 3D-QCA was the most accurate predictor of FFR <0.75 (C statistic 0.85, P < 0.001), while MLD measured by 2D-QCA was a similarly accurate predictor (C statistic 0.85, P < 0.001). In the side branch, the best metrics for predicting FFR <0.75 were % DS measured by 2D-QCA with a C statistic value of 0.91 (P < 0.001) and MLA measured by 3D-QCA with a C statistic value of 0.81 (P < 0.001). However, both 2D- and 3D-QCA metrics exhibited low accuracies for predicting FFR <0.75 in intermediate bifurcation lesions. 3D-QCA analysis for true bifurcation lesions did not improve the predictive accuracy of functionally significant FFR compared with 2D-QCA analysis. In lesions with intermediate stenosis, the diagnostic performance of both 2D- and 3D-QCA-derived measurements in differentiating functional severity is limited. © 2016 Wiley Periodicals, Inc.

Sugar maple height-diameter and age-diameter relationships in an uneven-aged northern hardwood stand

Science.gov (United States)

Laura S. Kenefic; R.D. Nyland

1999-01-01

Sugar maple (Acer saccharum Marsh.) height-diameter and age-diameter relationships are explored in a balanced uneven-aged northern hardwood stand in central New York. Results show that although both height and age vary considerably with diameter, these relationships can be described by statistically valid equations. The age-diameter relationship...

Proteomic profiling of tissue-engineered blood vessel walls constructed by adipose-derived stem cells.

Science.gov (United States)

Wang, Chen; Guo, Fangfang; Zhou, Heng; Zhang, Yun; Xiao, Zhigang; Cui, Lei

2013-02-01

Adipose-derived stem cells (ASCs) can differentiate into smooth muscle cells and have been engineered into elastic small diameter blood vessel walls in vitro. However, the mechanisms involved in the development of three-dimensional (3D) vascular tissue remain poorly understood. The present study analyzed protein expression profiles of engineered blood vessel walls constructed by human ASCs using methods of two-dimensional gel electrophoresis (2DE) and mass spectrometry (MS). These results were compared to normal arterial walls. A total of 1701±15 and 1265±26 protein spots from normal and engineered blood vessel wall extractions were detected by 2DE, respectively. A total of 20 spots with at least 2.0-fold changes in expression were identified, and 38 differently expressed proteins were identified by 2D electrophoresis and ion trap MS. These proteins were classified into seven functional categories: cellular organization, energy, signaling pathway, enzyme, anchored protein, cell apoptosis/defense, and others. These results demonstrated that 2DE, followed by ion trap MS, could be successfully utilized to characterize the proteome of vascular tissue, including tissue-engineered vessels. The method could also be employed to achieve a better understanding of differentiated smooth muscle protein expression in vitro. These results provide a basis for comparative studies of protein expression in vascular smooth muscles of different origin and could provide a better understanding of the mechanisms of action needed for constructing blood vessels that exhibit properties consistent with normal blood vessels.

33 CFR 90.3 - Pushing vessel and vessel being pushed: Composite unit.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Pushing vessel and vessel being... HOMELAND SECURITY INLAND NAVIGATION RULES INLAND RULES: INTERPRETATIVE RULES § 90.3 Pushing vessel and vessel being pushed: Composite unit. Rule 24(b) of the Inland Rules states that when a pushing vessel and...

33 CFR 82.3 - Pushing vessel and vessel being pushed: Composite unit.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Pushing vessel and vessel being... HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES 72 COLREGS: INTERPRETATIVE RULES § 82.3 Pushing vessel and vessel being pushed: Composite unit. Rule 24(b) of the 72 COLREGS states that when a pushing vessel and a...

New predictor of aortic enlargement in uncomplicated type B aortic dissection based on elliptic Fourier analysis.

Science.gov (United States)

Sato, Hiroshi; Ito, Toshiro; Kuroda, Yosuke; Uchiyama, Hiroki; Watanabe, Toshitaka; Yasuda, Naomi; Nakazawa, Junji; Harada, Ryo; Kawaharada, Nobuyoshi

2017-12-01

This study aimed to re-examine the conventional predictive factors for dissected aortic enlargement, such as the aortic and false lumen diameter and to consider whether the morphological elements of the dissected aorta could be predictors by quantifying the 'shape' of the true lumen based on elliptic Fourier analysis. A total of 80 patients with uncomplicated type B aortic dissection were included. The patients were divided into 'Enlargement group' and 'No Change group.' Between the 2 groups, the mean systolic blood pressure during follow-up, aortic and false lumen maximum diameters, and analysed morphological data were compared using each statistical method. The maximum aortic and false lumen diameters were significantly larger in the Enlargement group than in the No Change group (39.3 vs 35.9 mm; P = 0.0058) (23.5 vs 18.2 mm; P = 0.000095). The principal component 1, which is the data calculated by elliptic Fourier analysis, was significantly lower in the Enlargement group than in the No Change group (0.020 vs - 0.072; P = 0.000049). The mean systolic blood pressure ≥130 mmHg, aortic diameter, false lumen diameter and principal component 1 were included in the Cox proportional hazard model as covariates to determine the significant predictive variable. Principal component 1 demonstrated the only significance with aortic enlargement on multivariate analysis (odds ratio = 0.32; P = 0.048). The analysed and calculated morphological data of the shape of the true lumen can be more effective predictive factors of aortic enlargement of type B dissection than the conventional factors. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Dutch supplier rewarded for manufacture of the two vacuum vessels for the ATLAS end-cap toroids

CERN Multimedia

Maximilien Brice

2003-01-01

The ATLAS collaboration has presented an award for outstanding supplier performance to Dutch firm Schelde Exotech. Based on a design by Rutherford Appleton Laboratory, UK, Schelde Exotech manufactured under a NIKHEF contract the two 500 m3 large vacuum vessels for the cryostats of the ATLAS end-cap toroids. These 11-metre diameter castellated aluminium vessels with stainless-steel bore tube are essentially made up of 40-mm-thick plates for the shells, 75-mm-thick plates for the endplates, and 150-mm-thick bars for the flanges. Because of transport constraints, the vessels were made in halves, temporarily sealed and vacuum tested at the works, then transported to CERN for final assembly and acceptance tests. Both vessels were vacuum-tight and the meticulous and clean way of working ensured that a high vacuum was obtained within a few days of pumping. The delivery to CERN was completed in July 2002. Representatives of Schelde Exotech are seen here receiving their award in the ATLAS assembly hall. In the backgro...

Test results on direct containment heating by high-pressure melt ejection into the Surtsey vessel: The TDS test series

International Nuclear Information System (INIS)

Allen, M.D.; Blanchat, T.K.; Pilch, M.M.

1994-08-01

The Technology Development and Scoping (TDS) test series was conducted to test and develop instrumentation and procedures for performing steam-driven, high-pressure melt ejection (HPME) experiments at the Surtsey Test Facility to investigate direct containment heating (DCH). Seven experiments, designated TDS-1 through TDS-7, were performed in this test series. These experiments were conducted using similar initial conditions; the primary variable was the initial pressure in the Surtsey vessel. All experiments in this test series were performed with a steam driving gas pressure of ≅ 4 MPa, 80 kg of lumina/iron/chromium thermite melt simulant, an initial hole diameter of 4.8 cm (which ablated to a final hole diameter of ≅ 6 cm), and a 1/10th linear scale model of the Surry reactor cavity. The Surtsey vessel was purged with argon ( 2 ) to limit the recombination of hydrogen and oxygen, and gas grab samples were taken to measure the amount of hydrogen produced

Explosion properties of aluminum/oxidizer mixtures in a closed vessel; Aluminium/sankazai kongobutsu no mippei yokinai deno bakuhatsu tokusei

Energy Technology Data Exchange (ETDEWEB)

Miyake, A.; Aochi, T.; Shiraki, K.; Ogawa, T. [Yokohama National University, Yokohama (Japan). Faculty of Engineering

1995-10-31

In order to understand explosion properties of aluminum/oxidized mixtures for firework a closed vessel test was carried out, and pressure profile and ignition delay time were measured. It was found that flake aluminum (Al(f))/oxidized mixtures were more reactive and showed higher pressure values than those of atomized aluminum (Al(a))/oxidized mixtures. At a positive oxygen balance region Al(f)/oxidized mixtures showed a good agreement with the theoretically predicted values of combustion pressure at a constant volume. The combustion parameters with equilibrium calculation of aluminum/potassium chlorate showed almost the same ones of aluminum/potassium perchlorate. Furthermore, to investigate the influence of particle diameter of potassium chlorate on the explosion properties of Al(f)/potassium chlorate mixtures, the same kind of closed vessel test was performed and it was found that the mixtures became less sensitive and reactive with the increase of particle diameter. 17 refs., 7 figs., 2 tabs.

Standardized evaluation framework for evaluating coronary artery stenosis detection, stenosis quantification and lumen segmentation algorithms in computed tomography angiography.

Science.gov (United States)

Kirişli, H A; Schaap, M; Metz, C T; Dharampal, A S; Meijboom, W B; Papadopoulou, S L; Dedic, A; Nieman, K; de Graaf, M A; Meijs, M F L; Cramer, M J; Broersen, A; Cetin, S; Eslami, A; Flórez-Valencia, L; Lor, K L; Matuszewski, B; Melki, I; Mohr, B; Oksüz, I; Shahzad, R; Wang, C; Kitslaar, P H; Unal, G; Katouzian, A; Örkisz, M; Chen, C M; Precioso, F; Najman, L; Masood, S; Ünay, D; van Vliet, L; Moreno, R; Goldenberg, R; Vuçini, E; Krestin, G P; Niessen, W J; van Walsum, T

2013-12-01

Though conventional coronary angiography (CCA) has been the standard of reference for diagnosing coronary artery disease in the past decades, computed tomography angiography (CTA) has rapidly emerged, and is nowadays widely used in clinical practice. Here, we introduce a standardized evaluation framework to reliably evaluate and compare the performance of the algorithms devised to detect and quantify the coronary artery stenoses, and to segment the coronary artery lumen in CTA data. The objective of this evaluation framework is to demonstrate the feasibility of dedicated algorithms to: (1) (semi-)automatically detect and quantify stenosis on CTA, in comparison with quantitative coronary angiography (QCA) and CTA consensus reading, and (2) (semi-)automatically segment the coronary lumen on CTA, in comparison with expert's manual annotation. A database consisting of 48 multicenter multivendor cardiac CTA datasets with corresponding reference standards are described and made available. The algorithms from 11 research groups were quantitatively evaluated and compared. The results show that (1) some of the current stenosis detection/quantification algorithms may be used for triage or as a second-reader in clinical practice, and that (2) automatic lumen segmentation is possible with a precision similar to that obtained by experts. The framework is open for new submissions through the website, at http://coronary.bigr.nl/stenoses/. Copyright © 2013 Elsevier B.V. All rights reserved.

ETS transcription factor ELF5 induces lumen formation in a 3D model of mammary morphogenesis and its expression is inhibited by Jak2 inhibitor TG101348.

Science.gov (United States)

Chean, Jennifer; Chen, Charng-Jui; Shively, John E

2017-10-01

The loss of expression of a single gene can revert normal tissue to a malignant phenotype. For example, while normal breast has high lumenal expression of CEACAM1, the majority of breast cancers exhibit the early loss of this gene with the concurrent loss of their lumenal phenotype. MCF7 cells that lack CEACAM1 expression and fail to form lumena in 3D culture, regain the normal phenotype when transfected with CEACAM1. In order to probe the mechanism of this gain of function, we treated these cells with the clinically relevant Jak2 inhibitor TG101348 (TG), expecting that disruption of the prolactin receptor signaling pathway would interfere with the positive effects of transfection of MCF7 cells with CEACAM1. Indeed, lumen formation was inhibited, resulting in the down regulation of a set of genes, likely involved in the complex process of lumen formation. As expected, inhibition of the expression of many of these genes also inhibited lumen formation, confirming their involvement in a single pathway. Among the genes identified by the inhibition assay, ETS transcription factor ELF5 stood out, since it has been identified as a master regulator of mammary morphogenesis, and is associated with prolactin receptor signaling. When ELF5 was transfected into the parental MCF7 cells that lack CEACAM1, lumen formation was restored, indicating that ELF5 can replace CEACAM1 in this model system of lumenogenesis. We conclude that the event(s) that led to the loss of expression of CEACAM1 is epistatic in that multiple genes associated with a critical pathway were affected, but that restoration of the normal phenotype can be achieved with reactivation of certain genes at various nodal points in tissue morphogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Comparison of In-Vessel Shielding Design Concepts between Sodium-cooled Fast Burner Reactor and the Sodium-cooled Fast Breeder Reactor

International Nuclear Information System (INIS)

Yun, Sunghwan; Kim, Sang Ji

2015-01-01

In this study, quantities of in-vessel shields were derived and compared each other based on the replaceable shield assembly concept for both of the breeder and burner SFRs. Korean Prototype Gen-IV Sodium-cooled Fast Reactor (PGSFR) like SFR was used as the reference reactor and calculation method reported in the reference was used for shielding analysis. In this paper, characteristics of in-vessel shielding design were studied for the burner SFR and breeder SFR based on the replaceable shield assembly concept. An in-vessel shield to prevent secondary sodium activation (SSA) in the intermediate heat exchangers (IHXs) is one of the most important structures for the pool type Sodium-cooled Fast Reactor (SFR). In our previous work, two in-vessel shielding design concepts were compared each other for the burner SFR. However, a number of SFRs have been designed and operated with the breeder concept, in which axial and radial blankets were loaded for fuel breeding, during the past several decades. Since axial and radial blanket plays a role of neutron shield, comparison of required in-vessel shield amount between the breeder and burner SFRs may be an interesting work for SFR designer. Due to the blanket, the breeder SFR showed better performance in axial neutron shielding. Hence, 10.1 m diameter reactor vessel satisfied the design limit of SSA at the IHXs. In case of the burner SFR, due to more significant axial fast neutron leakage, 10.6 m diameter reactor vessel was required to satisfy the design limit of SSA at the IHXs. Although more efficient axial shied such as a mixture of ZrH 2 and B 4 C can improve shielding performance of the burner SFR, additional fabrication difficulty may mitigate the advantage of improved shielding performance. Therefore, it can be concluded that the breeder SFR has better characteristic in invessel shielding design to prevent SSA at the IHXs than the burner SFR in the pool-type reactor

Lumen and Chromaticity Maintenance of LED PAR38 Lamps Operated in Steady-State Conditions

Energy Technology Data Exchange (ETDEWEB)

Royer, Michael P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-12-01

The lumen depreciation and color shift of 38 different lamps (32 LED, 2 CFL, 1 ceramic metal halide [CMH], 3 halogen) were monitored in a specially developed automated long-term test apparatus (ALTA2) for nearly 14,000 hours. Five samples of each lamp model were tested, with measurements recorded on a weekly basis. The lamps were operated continuously at a target ambient temperature between 44°C and 45°C.

Single- and double- lumen silicone breast implant integrity: prospective evaluation of MR and US criteria.

Science.gov (United States)

Berg, W A; Caskey, C I; Hamper, U M; Kuhlman, J E; Anderson, N D; Chang, B W; Sheth, S; Zerhouni, E A

1995-10-01

To evaluate the accuracy of magnetic resonance (MR) and ultrasound (US) criteria for breast implant integrity. One hundred twenty-two single-lumen silicone breast implants and 22 bilumen implants were evaluated with surface coil MR imaging and US and surgically removed. MR criteria for implant failure were a collapsed implant shell ("linguine sign"), foci of silicone outside the shell ("noose sign"), and extracapsular gel, US criteria were collapsed shell, low-level echoes within the gel, and "snowstorm" echoes of extracapsular silicone. Among single-lumen implants, MR imaging depicted 39 of 40 ruptures, 14 of 28 with minimal leakage; 49 of 54 intact implants were correctly interpreted. US depicted 26 of 40 ruptured implants, four of 28 with minimal leakage, and 30 of 54 intact implants. Among bilumen implants, MR imaging depicted four of five implants with rupture of both lumina and nine of 10 as intact; US depicted one rupture and helped identify two of 10 as intact. Mammography accurately depicted the status of 29 of 30 bilumen implants with MR imaging correlation. MR imaging depicts implant integrity more accurately than US; neither method reliably depicts minimal leakage with shell collapse. Mammography is useful in screening bilumen implant integrity.

Distinct patterns of inflammation in the airway lumen and bronchial mucosa of children with cystic fibrosis.

Science.gov (United States)

Regamey, Nicolas; Tsartsali, Lemonia; Hilliard, Tom N; Fuchs, Oliver; Tan, Hui-Leng; Zhu, Jie; Qiu, Yu-Sheng; Alton, Eric W F W; Jeffery, Peter K; Bush, Andrew; Davies, Jane C

2012-02-01

Studies in cystic fibrosis (CF) generally focus on inflammation present in the airway lumen. Little is known about inflammation occurring in the airway wall, the site ultimately destroyed in end-stage disease. To test the hypothesis that inflammatory patterns in the lumen do not reflect those in the airway wall of children with CF. Bronchoalveolar lavage (BAL) fluid and endobronchial biopsies were obtained from 46 children with CF and 16 disease-free controls. BAL cell differential was assessed using May-Gruenwald-stained cytospins. Area profile counts of bronchial tissue immunopositive inflammatory cells were determined. BAL fluid from children with CF had a predominance of neutrophils compared with controls (median 810×10(3)/ml vs 1×10(3)/ml, p<0.0001). In contrast, subepithelial bronchial tissue from children with CF was characterised by a predominance of lymphocytes (median 961 vs 717 cells/mm(2), p=0.014), of which 82% were (CD3) T lymphocytes. In chest exacerbations, BAL fluid from children with CF had more inflammatory cells of all types compared with those with stable disease whereas, in biopsies, only the numbers of lymphocytes and macrophages, but not of neutrophils, were higher. A positive culture of Pseudomonas aeruginosa was associated with higher numbers of T lymphocytes in subepithelial bronchial tissue (median 1174 vs 714 cells/mm(2), p=0.029), but no changes were seen in BAL fluid. Cell counts in BAL fluid and biopsies were positively correlated with age but were unrelated to each other. The inflammatory response in the CF airway is compartmentalised. In contrast to the neutrophil-dominated inflammation present in the airway lumen, the bronchial mucosa is characterised by the recruitment and accumulation of lymphocytes.

Relaxin 2 fails to lower intraocular pressure and to dilate retinal vessels in rats.

Science.gov (United States)

Hampel, Ulrike; Träger, Katharina; Liu, Hanhan; Teister, Julia; Grus, Franz; Prokosch-Willing, Verena

2018-03-13

Recently, the vasodilator relaxin 2 has been introduced as a treatment for acute heart failure. However, its role on vessels of the eye and intraocular pressure (IOP) remains unclear though it has been hypothesized to induce a decrease IOP after intramuscular injection in humans. We aimed to test whether the hormone relaxin 2 lowers IOP and dilates retinal vessels in animals. The IOP of female Sprague-Dawley rats before and after application of relaxin 2 was measured using an Icare Tonolab device calibrated for rats. Recombinant human relaxin 2 in phosphate-buffered saline with 0.1% bovine serum albumin was either applied as eye drops (1000, 2000 or 3000 ng/ml), injected intravitreally (500 ng/ml) or intravenously (13.3 μg/kg body weight). Retinal vessel thickness was monitored using infrared fundus images compiled with optical coherence tomography (Heidelberg Engineering) before and several time points after application of relaxin 2. Neither topical nor intravitreous or intravenous application of relaxin 2 lowered the IOP or changed the arterial or venous vessel diameter after 1 or 3 h after application. Now that relaxin 2 is more easily available, the hormone came again into focus as a potential glaucoma therapeutic. However, our study in rats could not support the hypothesis that relaxin 2 lowers IOP or dilates retinal vessels.

Frazzled/DCC facilitates cardiac cell outgrowth and attachment during Drosophila dorsal vessel formation.

Science.gov (United States)

Macabenta, Frank D; Jensen, Amber G; Cheng, Yi-Shan; Kramer, Joseph J; Kramer, Sunita G

2013-08-15

Drosophila embryonic dorsal vessel (DV) morphogenesis is a highly stereotyped process that involves the migration and morphogenesis of 52 pairs of cardioblasts (CBs) in order to form a linear tube. This process requires spatiotemporally-regulated localization of signaling and adhesive proteins in order to coordinate the formation of a central lumen while maintaining simultaneous adhesion between CBs. Previous studies have shown that the Slit/Roundabout and Netrin/Unc5 repulsive signaling pathways facilitate site-specific loss of adhesion between contralateral CBs in order to form a luminal space. However, the concomitant mechanism by which attraction initiates CB outgrowth and discrete localization of adhesive proteins remains poorly understood. Here we provide genetic evidence that Netrin signals through DCC (Deleted in Colorectal Carcinoma)/UNC-40/Frazzled (Fra) to mediate CB outgrowth and attachment and that this function occurs prior to and independently of Netrin/UNC-5 signaling. fra mRNA is expressed in the CBs prior to and during DV morphogenesis. Loss-of-fra-function results in significant defects in cell shape and alignment between contralateral CB rows. In addition, CB outgrowth and attachment is impaired in both fra loss- and gain-of-function mutants. Deletion of both Netrin genes (NetA and NetB) results in CB attachment phenotypes similar to fra mutants. Similar defects are also seen when both fra and unc5 are deleted. Finally we show that Fra accumulates at dorsal and ventral leading edges of paired CBs, and this localization is dependent upon Netrin. We propose that while repulsive guidance mechanisms contribute to lumen formation by preventing luminal domains from coming together, site-specific Netrin/Frazzled signaling mediates CB attachment. Copyright © 2013 Elsevier Inc. All rights reserved.

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.

Ultrasound assessment of the posterior circumflex humeral artery in elite volleyball players: Aneurysm prevalence, anatomy, branching pattern and vessel characteristics.

Science.gov (United States)

van de Pol, Daan; Maas, Mario; Terpstra, Aart; Pannekoek-Hekman, Marja; Alaeikhanehshir, Sena; Kuijer, P Paul F M; Planken, R Nils

2017-03-01

To determine the prevalence of posterior circumflex humeral artery (PCHA) aneurysms and vessel characteristics of the PCHA and deep brachial artery (DBA) in elite volleyball players. Two-hundred and eighty players underwent standardized ultrasound assessment of the dominant arm by a vascular technologist. Assessment included determination of PCHA aneurysms (defined as segmental vessel dilatation ≥150 %), PCHA and DBA anatomy, branching pattern, vessel course and diameter. The PCHA and DBA were identified in 100 % and 93 % (260/280) of cases, respectively. The prevalence of PCHA aneurysms was 4.6 % (13/280). All aneurysms were detected in proximal PCHA originating from the axillary artery (AA). The PCHA originated from the AA in 81 % of cases (228/280), and showed a curved course dorsally towards the humeral head in 93 % (211/228). The DBA originated from the AA in 73 % of cases (190/260), and showed a straight course parallel to the AA in 93 % (177/190). PCHA aneurysm prevalence in elite volleyball players is high and associated with a specific branching type: a PCHA that originates from the axillary artery. Radiologists should have a high index of suspicion for this vascular overuse injury. For the first time vessel characteristics and reference values are described to facilitate ultrasound assessment. • Prevalence of PCHA aneurysms is 4.6 % among elite volleyball players. • All aneurysms are in proximal PCHA that originates directly from AA. • Vessel characteristics and reference values are described to facilitate US assessment. • Mean PCHA and DBA diameters can be used as reference values. • Radiologists need a high index of suspicion for this vascular overuse injury.

Conceptual design studies of in-vessel viewing equipment for ITER

International Nuclear Information System (INIS)

Obara, Kenjiro; Oka, Kiyoshi; Taguchi, Hiroshi; Itoh, Akira; Tada, Eisuke; Shibanuma, Kiyoshi

1996-03-01

In-vessel viewing systems are essential to inspect all surface of in-vessel components so as to detect and locate damages, and to assist in-vessel maintenance operations. The in-vessel viewing operations are categorized into the three cases, which are 1) rapid inspection just after off-normal events such as disruption, 2) scheduled inspection, and 3) supplementary inspection during maintenance operations. In case of the rapid inspection, the viewing systems have to be operated in vacuum (ca. 10 -5 Pa) and high temperature (ca. 300degC) under a gamma ray dose rate of 10 7 R/h. On the other hand, the latter two cases are anticipated to be under atmospheric inert gas, 150degC and 3x10 6 R/h. Accordingly, the in-vessel viewing systems are required to have sufficient durability under those conditions of all cases as well as precision of the vision to all of in-vessel surface. Based on those requirements, scoping studies on various viewing concepts have been performed and the applicability to the ITER conditions have been assessed. As a result, two types of viewing systems have been chosen, which are a periscope type viewing system and a image fiber type viewing system with a multi-joint manipulator. Both systems are based on radiation hard optical elements which are being developed. In this report, the design features of both viewing systems are described, including technical issues for ITER application. Finally, a periscope type viewing system is recommended as a primary system and the following specifications/conditions are proposed for the further engineering design. (1) Unified type periscope with a movable mirror at the tip (2) Integrated lighting device into the periscope (3) Accessed from top vertical ports located at 7.3m from the machine center (4) Proposed configuration with a total length of around 27m and a diameter of 200mm. (author)

Contura Multi-Lumen Balloon Breast Brachytherapy Catheter: Comparative Dosimetric Findings of a Phase 4 Trial

Energy Technology Data Exchange (ETDEWEB)

Arthur, Douglas W., E-mail: darthur@mcvh-vcu.edu [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States); Vicini, Frank A. [Michigan Healthcare Professionals/21st Century Oncology, Farmington Hills, Michigan (United States); Todor, Dorin A. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States); Julian, Thomas B. [Allegheny General Hospital, Temple University School of Medicine, Pittsburgh, Pennsylvania (United States); Cuttino, Laurie W.; Mukhopadhyay, Nitai D. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States)

2013-06-01

Purpose: Final dosimetric findings of a completed, multi-institutional phase 4 registry trial using the Contura Multi-Lumen Balloon (MLB) breast brachytherapy catheter to deliver accelerated partial breast irradiation (APBI) in patients with early-stage breast cancer are presented. Methods and Materials: Three dosimetric plans with identical target coverage were generated for each patient for comparison: multilumen multidwell (MLMD); central-lumen multidwell (CLMD); and central-lumen single-dwell (CLSD) loading of the Contura catheter. For this study, a successful treatment plan achieved ideal dosimetric goals and included the following: ≥95% of the prescribed dose (PD) covering ≥95% of the target volume (TV); maximum skin dose ≤125% of the PD; maximum rib dose ≤145% of the PD; and V150 ≤50 cc and V200 ≤10 cc. Results: Between January 2008 and February 2011, 23 institutions participated. A total of 318 patients were available for dosimetric review. Using the Contura MLB, all dosimetric criteria were met in 78.93% of cases planned with MLMD versus 55.38% with the CLMD versus 37.66% with the CLSD (P≤.0001). Evaluating all patients with the full range of skin to balloon distance represented, median maximum skin dose was reduced by 12% and median maximum rib dose by 13.9% when using MLMD-based dosimetric plans compared to CLSD. The dosimetric benefit of MLMD was further demonstrated in the subgroup of patients where skin thickness was <5 mm, where MLMD use allowed a 38% reduction in median maximum skin dose over CLSD. For patients with rib distance <5 mm, the median maximum rib dose reduction was 27%. Conclusions: Use of the Contura MLB catheter produced statistically significant improvements in dosimetric capabilities between CLSD and CLMD treatments. This device approach demonstrates the ability not only to overcome the barriers of limited skin thickness and close rib proximity, but to consistently achieve a higher standard of dosimetric planning goals.

Contura Multi-Lumen Balloon breast brachytherapy catheter: comparative dosimetric findings of a phase 4 trial.

Science.gov (United States)

Arthur, Douglas W; Vicini, Frank A; Todor, Dorin A; Julian, Thomas B; Cuttino, Laurie W; Mukhopadhyay, Nitai D

2013-06-01

Final dosimetric findings of a completed, multi-institutional phase 4 registry trial using the Contura Multi-Lumen Balloon (MLB) breast brachytherapy catheter to deliver accelerated partial breast irradiation (APBI) in patients with early-stage breast cancer are presented. Three dosimetric plans with identical target coverage were generated for each patient for comparison: multilumen multidwell (MLMD); central-lumen multidwell (CLMD); and central-lumen single-dwell (CLSD) loading of the Contura catheter. For this study, a successful treatment plan achieved ideal dosimetric goals and included the following: ≥ 95% of the prescribed dose (PD) covering ≥ 95% of the target volume (TV); maximum skin dose ≤ 125% of the PD; maximum rib dose ≤ 145% of the PD; and V150 ≤50 cc and V200 ≤ 10 cc. Between January 2008 and February 2011, 23 institutions participated. A total of 318 patients were available for dosimetric review. Using the Contura MLB, all dosimetric criteria were met in 78.93% of cases planned with MLMD versus 55.38% with the CLMD versus 37.66% with the CLSD (P ≤.0001). Evaluating all patients with the full range of skin to balloon distance represented, median maximum skin dose was reduced by 12% and median maximum rib dose by 13.9% when using MLMD-based dosimetric plans compared to CLSD. The dosimetric benefit of MLMD was further demonstrated in the subgroup of patients where skin thickness was <5 mm, where MLMD use allowed a 38% reduction in median maximum skin dose over CLSD. For patients with rib distance <5 mm, the median maximum rib dose reduction was 27%. Use of the Contura MLB catheter produced statistically significant improvements in dosimetric capabilities between CLSD and CLMD treatments. This device approach demonstrates the ability not only to overcome the barriers of limited skin thickness and close rib proximity, but to consistently achieve a higher standard of dosimetric planning goals. Copyright © 2013 Elsevier Inc. All rights

Flow-induced endothelial cell alignment requires the RhoGEF Trio as a scaffold protein to polarize active Rac1 distribution

NARCIS (Netherlands)

Kroon, Jeffrey; Heemskerk, Niels; Kalsbeek, Martin J. T.; de Waard, Vivian; van Rijssel, Jos; van Buul, Jaap D.

2017-01-01

Endothelial cells line the lumen of the vessel wall and are exposed to flow. In linear parts of the vessel, the endothelial cells experience laminar flow, resulting in endothelial cell alignment in the direction of flow, thereby protecting the vessel wall from inflammation and permeability. In order

A multi-scale tensor voting approach for small retinal vessel segmentation in high resolution fundus images.

Science.gov (United States)

Christodoulidis, Argyrios; Hurtut, Thomas; Tahar, Houssem Ben; Cheriet, Farida

2016-09-01

Segmenting the retinal vessels from fundus images is a prerequisite for many CAD systems for the automatic detection of diabetic retinopathy lesions. So far, research efforts have concentrated mainly on the accurate localization of the large to medium diameter vessels. However, failure to detect the smallest vessels at the segmentation step can lead to false positive lesion detection counts in a subsequent lesion analysis stage. In this study, a new hybrid method for the segmentation of the smallest vessels is proposed. Line detection and perceptual organization techniques are combined in a multi-scale scheme. Small vessels are reconstructed from the perceptual-based approach via tracking and pixel painting. The segmentation was validated in a high resolution fundus image database including healthy and diabetic subjects using pixel-based as well as perceptual-based measures. The proposed method achieves 85.06% sensitivity rate, while the original multi-scale line detection method achieves 81.06% sensitivity rate for the corresponding images (p<0.05). The improvement in the sensitivity rate for the database is 6.47% when only the smallest vessels are considered (p<0.05). For the perceptual-based measure, the proposed method improves the detection of the vasculature by 7.8% against the original multi-scale line detection method (p<0.05). Copyright © 2016 Elsevier Ltd. All rights reserved.

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...

Comprehending the structure of a vacuum vessel and in-vessel components of fusion machines. 1. Comprehending the vacuum vessel structure

International Nuclear Information System (INIS)

Onozuka, Masanori; Nakahira, Masataka

2006-01-01

The functions, conditions and structure of vacuum vessel using tokamak fusion machines are explained. The structural standard and code of vacuum vessel, process of vacuum vessel design, and design of ITER vacuum vessel are described. Production and maintenance of ultra high vacuum, confinement of radioactive materials, support of machines in vessel and electromagnetic force, radiation shield, plasma vertical stability, one-turn electric resistance, high temperature baking heat and remove of nuclear heat, reduce of troidal ripple, structural standard, features of safety of nuclear fusion machines, subjects of structural standard of fusion vacuum vessel, design flow of vacuum vessel, establishment of radial build, selections of materials, baking and cooling method, basic structure, structure of special parts, shield structure, and of support structure, and example of design of structure, ITER, are stated. (S.Y.)

Wood quality changes caused by mineral fertilization

Directory of Open Access Journals (Sweden)

Carlos Roberto Sette Jr

2014-06-01

Full Text Available The diverse and important use of wood from fast growth eucalyptus plantations requires the analysis of the effect of mineral fertilizers on wood quality. The objective of this study was to evaluate the anatomical characteristics and wood density from Eucalyptus grandis trees (3 m x 2 m spacing fertilized with potassium and sodium (at planting, 6 th and 12th month. Fifteen (15 6 years old eucalyptus trees were selected (5 trees/treatment, cut and wood samples at DBH (1,3 m were taken for anatomical characteristics (fiber and vessels and wood density analysis. Results showed that eucalyptus trees treated with mineral fertilizers did not show significant alteration in average wood density, with radial profile model common to all three treatments, characterized by a values increase in the region next to the pith, toward to bark. Mineral fertilization influenced wood anatomical characteristics: treatment with sodium was characterized by thinner walls and lumen larger diameter; in treatment with potassium, larger vessels were detected.

Metallurgical failure investigation of a pipe connector fracture of an expansion vessel

International Nuclear Information System (INIS)

Neidel, Andreas

2016-01-01

A pipe connector of an expansion vessel of a safety heat exchanger was torn off in a test facility's natural gas compressor. From a material point of view, the cause of the damage is a fatigue fracture induced by pulsating bending stress. The fatigue fracture originated from both, the pipe's outer surface as well as from its inner surface, which is consistent with the given stress situation (pulsating bending stress). Material defects or welding-induced flaws were not observed. Corrosion, wear, or thermal overload which may have promoted the damage, were not observed either. The primary cause was a major design error. Cases of dynamic load were obviously not duly taken into account during designing, so that the free-swinging mass of the expansion vessel which was mounted to a pipe of a diameter of only half an inch and, furthermore, installed in an angle of 45 (additional static preload.), could cause the fatigue failure induced by pulsating bending stress in the zone of highest stresses at the transition of the expansion vessel and the the pipe connector due to dynamic operating loads which always occur in plants like these.

Mechanical Recanalization of Subacute Vessel Occlusion in Peripheral Arterial Disease with a Directional Atherectomy Catheter

Energy Technology Data Exchange (ETDEWEB)

Massmann, Alexander, E-mail: Alexander.Massmann@uks.eu; Katoh, Marcus [Saarland University Hospital, Department of Diagnostic and Interventional Radiology (Germany); Shayesteh-Kheslat, Roushanak [Saarland University Hospital, Department of General Surgery, Visceral, Vascular, and Pediatric Surgery (Germany); Buecker, Arno [Saarland University Hospital, Department of Diagnostic and Interventional Radiology (Germany)

2012-10-15

Purpose: To retrospectively examine the technical feasibility and safety of directional atherectomy for treatment of subacute infrainguinal arterial vessel occlusions. Methods: Five patients (one woman, four men, age range 51-81 years) with peripheral arterial disease who experienced sudden worsening of their peripheral arterial disease-related symptoms during the last 2-6 weeks underwent digital subtraction angiography, which revealed vessel occlusion in native popliteal artery (n = 4) and in-stent occlusion of the superficial femoral artery (n = 1). Subsequently, all patients were treated by atherectomy with the SilverHawk (ev3 Endovascular, USA) device. Results: The mean diameter of treated vessels was 5.1 {+-} 1.0 mm. The length of the occlusion ranged 2-14 cm. The primary technical success rate was 100%. One patient experienced a reocclusion during hospitalization due to heparin-induced thrombocytopenia. There were no further periprocedural complications, in particular no peripheral embolizations, until hospital discharge or during the follow-up period of 1 year. Conclusion: The recanalization of infrainguinal arterial vessel occlusions by atherectomy with the SilverHawk device is technically feasible and safe. In our limited retrospective study, it was associated with a high technical success rate and a low procedure-related complication rate.

Prospective ECG-triggered axial CT at 140-kV tube voltage improves coronary in-stent restenosis visibility at a lower radiation dose compared with conventional retrospective ECG-gated helical CT

Energy Technology Data Exchange (ETDEWEB)

Horiguchi, Jun; Fujioka, Chikako; Kiguchi, Masao; Kohno, Shingo [Hiroshima University Hospital, Department of Clinical Radiology, Hiroshima (Japan); Yamamoto, Hideya; Kitagawa, Toshiro [Hiroshima University, Department of Molecular and Internal Medicine, Division of Clinical Medical Science, Programs for Applied Biomedicine, Graduate School of Biomedical Sciences, Hiroshima (Japan); Ito, Katsuhide [Hiroshima University, Department of Radiology, Division of Medical Intelligence and Informatics, Programs for Applied Biomedicine, Graduate School of Biomedical Sciences, Hiroshima (Japan)

2009-10-15

The purpose of this study was to compare coronary 64-slice CT angiography (CTA) protocols, specifically prospective electrocardiograph (ECG)-triggered and retrospective ECG-gated CT acquisition performed using a tube voltage of 140 kV and 120 kV, regarding intracoronary stent imaging. Coronary artery stents (n=12) with artificial in-stent restenosis (50% luminal reduction, 40 HU) on a cardiac phantom were examined by CT at heart rates of 50-75 beats per minute (bpm). The subjective visibility of in-stent restenosis was evaluated with a three-point scale (1 clearly visible, 2 visible, and 3 not visible), and artificial lumen narrowing [(inner stent diameter - measured lumen diameter)/inner stent diameter], lumen attenuation increase ratio [(in-stent attenuation - coronary lumen attenuation)/coronary lumen attenuation], and signal-to-noise ratio of in-stent lumen were determined. The effective dose was estimated. The artificial lumen narrowing (mean 43%), the increase of lumen attenuation (mean 46%), and signal-to-noise ratio (mean 7.8) were not different between CT acquisitions (p=0.12-0.91). However, the visibility scores of in-stent restenosis were different (p<0.05) between ECG-gated CTA techniques: (a) 140-kV prospective (effective dose 4.6 mSv), 1.6; (b) 120-kV prospective (3.3 mSv), 1.8; (c) 140-kV retrospective (16.4-18.8 mSv), 1.9; and (d) 120-kV retrospective (11.0-13.4 mSv), 1.9. Thus, 140-kV prospective ECG-triggered CTA improves coronary in-stent restenosis visibility at a lower radiation dose compared with retrospective ECG-gated CTA. (orig.)

Design Evaluation of UIS and In-vessel Fuel Transfer Machine for a 1200MWe SFR

Energy Technology Data Exchange (ETDEWEB)

Lee, Jae Han; Kim, Seok Hoon; Park, Chang Gyu; Lee, Su Yeon

2008-11-15

The report describes the structural applicability of the upper internal structure (UIS) and the in-vessel fuel transfer machine for a 1200MWe sodium cooled fast reactor (SFR) of a pool type. In the conceptual design, a two rotating plug type as a refueling system is considered. For the two rotating plug type, the diameters of large and small rotating plugs are determined by 7.2m and 5.6m, respectively. Through the use of an inner fuel transfer machine and the lift change machine with a fixed arm length of 1.10m installed on a small rotating plug, all the core assemblies are accessed within 7mm accuracy. The UIS diameter is determined by 4.7m, which includes the all control drive lines in upper part, the diameter of UIS lower part is restricted by 4.4 m to secure the rotation angle of a refueling machine.

Coronary artery wall imaging in mice using osmium tetroxide and micro-computed tomography (micro-CT)

International Nuclear Information System (INIS)

Pai, Vinay M.; Kozlowski, Megan; Donahue, Danielle; Miller, Elishiah; Xiao, Xianghui; Chen, Marcus Y.; Yu, Zu-Xi; Connelly, Patricia; Jeffries, Kenneth; Wen, Han

2012-01-01

The high spatial resolution of micro-computed tomography (micro-CT) is ideal for 3D imaging of coronary arteries in intact mouse heart specimens. Previously, micro-CT of mouse heart specimens utilized intravascular contrast agents that hardened within the vessel lumen and allowed a vascular cast to be made. However, for mouse coronary artery disease models, it is highly desirable to image coronary artery walls and highlight plaques. For this purpose, we describe an ex vivo contrast-enhanced micro-CT imaging technique based on tissue staining with osmium tetroxide (OsO 4 ) solution. As a tissue-staining contrast agent, OsO 4 is retained in the vessel wall and surrounding tissue during the fixation process and cleared from the vessel lumens. Its high X-ray attenuation makes the artery wall visible in CT. Additionally, since OsO 4 preferentially binds to lipids, it highlights lipid deposition in the artery wall. We performed micro-CT of heart specimens of 5- to 25-week-old C57BL/6 wild-type mice and 5- to 13-week-old apolipoprotein E knockout (apoE -/- ) mice at 10 μm resolution. The results show that walls of coronary arteries as small as 45 μm in diameter are visible using a table-top micro-CT scanner. Similar image clarity was achieved with 1/2000th the scan time using a synchrotron CT scanner. In 13-week-old apoE mice, lipid-rich plaques are visible in the aorta. Our study shows that the combination of OsO 4 and micro-CT permits the visualization of the coronary artery wall in intact mouse hearts.

Conjugate heat transfer analysis for in-vessel retention with external reactor vessel cooling

International Nuclear Information System (INIS)

Park, Jong-Woon; Bae, Jae-ho; Song, Hyuk-Jin

2016-01-01

Highlights: • A conjugate heat transfer analysis method is applied for in-vessel corium retention. • 3D heat diffusion has a formidable effect in alleviating focusing heat load from metallic layer. • The focusing heat load is decreased by about 2.5 times on the external surface. - Abstract: A conjugate heat transfer analysis method for the thermal integrity of a reactor vessel under external reactor vessel cooling conditions is developed to resolve light metal layer focusing effect issue for in-vessel retention. The method calculates steady-state three-dimensional temperature distribution of a reactor vessel using coupled conjugate heat transfer between in-vessel three-layered stratified corium (metallic pool, oxide pool and heavy metal and polar-angle dependent boiling heat transfer at the outer surface of a reactor vessel). The three-layer corium heat transfer model is utilizing lumped-parameter thermal-resistance circuit method. For the ex-vessel boiling boundary conditions, nucleate, transition and film boiling are considered. The thermal integrity of a reactor vessel is addressed in terms of heat flux at the outer-most nodes of the vessel and remaining thickness profile. The vessel three-dimensional heat conduction is validated against a commercial code. It is found that even though the internal heat flux from the metal layer goes far beyond critical heat flux (CHF) the heat flux from the outermost nodes of the vessel may be maintained below CHF due to massive vessel heat diffusion. The heat diffusion throughout the vessel is more pronounced for relatively low heat generation rate in an oxide pool. Parametric calculations are performed considering thermal conditions such as peak heat flux from a light metal layer, heat generation in an oxide pool and external boiling conditions. The major finding is that the most crucial factor for success of in-vessel retention is not the mass of the molten light metal above the oxide pool but the heat generation rate

Heat dissipation research on the water-cooling channel of HL-2M in-vessel coils

Energy Technology Data Exchange (ETDEWEB)

Jiang, J., E-mail: jiangjiaming@swip.ac.cn; Liu, Y.; Chen, Q.; Ji, X.Q.

2017-04-15

Highlights: • The joule heat of in-vessel coils is very difficult to dissipate inside HL-2M vacuum vessel. • Heat dissipation model of the coil includes the joule heat model, the heat conduction model and the heat transfer model. • The CFD analysis has been done for the coil-water cooling, with comparison with the date of theoretical analysis and experiment. • The result shows water-cooling channel is good for the joule heat transfer and taken away. - Abstract: HL-2M in-vessel coils are positioned in high vacuum circumstance, and they will generate joule heat when they carry 15 kA electrical current, but joule heat is very difficult to dissipate in vacuum, so a hollow cable with 8 mm inner diameter is design as water-cooling channel for heat convection. By using the methods of the theoretical derivation, together with CFD numeric simulation method and the experiment of the heat transfer, the water channel of HL-2M in-vessel coils has been studied, and the temperature of HL-2M in-vessel coils under different cooling water flow rates is obtained and acceptable. Simultaneously, the external cooling water supply system parameters for the water-cooling channel of the coils are estimated. Three methods’ results are in good agreement; the theoretical model is verified and could be popularized for predicting the temperature rise of HL-2M in-vessel coils.

A study on ex-vessel steam explosion for a flooded reactor cavity of reactor scale - 15216

International Nuclear Information System (INIS)

Song, S.; Yoon, E.; Kim, Y.; Cho, Y.

2015-01-01

A steam explosion can occur when a molten corium is mixed with a coolant, more volatile liquid. In severe accidents, corium can come into contact with coolant either when it flows to the bottom of the reactor vessel and encounters the reactor coolant, or when it breaches the reactor vessel and flows into the reactor containment. A steam explosion could then threaten the containment structures, such as the reactor vessel or the concrete walls/penetrations of the containment building. This study is to understand the shortcomings of the existing analysis code (TEXAS-V) and to estimate the steam explosion loads on reactor scale and assess the effect of variables, then we compared results and physical phenomena. Sensitivity study of major parameters for initial condition is performed. Variables related to melt corium such as corium temperature, falling velocity and diameter of melt are more important to the ex-vessel steam explosion load and the steam explosion loads are proportional to these variables related to melt corium. Coolant temperature on reactor cavity has a specific area to increase the steam explosion loads. These results will be used to evaluate the steam explosion loads using ROAAM (Risk Oriented Accident Analysis Methodology) and to develop the evaluation methodology of ex-vessel steam explosion. (authors)

Neutron and Gamma Fluxes and dpa Rates for HFIR Vessel Beltline Region (Present and Upgrade Designs)

Energy Technology Data Exchange (ETDEWEB)

Blakeman, E.D.

2001-01-11

The Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR) is currently undergoing an upgrading program, a part of which is to increase the diameters of two of the four radiation beam tubes (HB-2 and HB-4). This change will cause increased neutron and gamma radiation dose rates at and near locations where the tubes penetrate the vessel wall. Consequently, the rate of radiation damage to the reactor vessel wall at those locations will also increase. This report summarizes calculations of the neutron and gamma flux (particles/cm{sup 2}/s) and the dpa rate (displacements/atom/s) in iron at critical locations in the vessel wall. The calculated dpa rate values have been recently incorporated into statistical damage evaluation codes used in the assessment of radiation induced embrittlement. Calculations were performed using models based on the discrete ordinates methodology and utilizing ORNL two-dimensional and three-dimensional discrete ordinates codes. Models for present and proposed beam tube designs are shown and their results are compared. Results show that for HB-2, the dpa rate in the vessel wall where the tube penetrates the vessel will be increased by {approximately}10 by the proposed enlargement. For HB-4, a smaller increase of {approximately}2.6 is calculated.

The role of CT and MR in diagnosis of aortic dissection

International Nuclear Information System (INIS)

Yoon, Kwon Ha; Lim, Tae Hwan; Song, Koun Sik; Min, Kyung Seok; Song, Meong Gun

1994-01-01

The purpose of this study was to determine the role of CT and MR imagings in the diagnosis of aortic dissection and differentiation between the true and false lumen. We retrospectively studied forty patients with aortic dissection(AD) diagnosed by imagings or surgery. Of the forty patients, 19 were examined with only CT, 14 with CT and MR, and 7 with MR. Our points of view were(1) the classification of AD according to configuration of intimal flap by cross-sectional imaging, (2) differentiation between the true and false lumens, (3) the course of the false lumen, and (4) detectability of the origin of major branch vessels of the abdominal aorta. The classification by cross-sectional imaging were crescentic(65%), circumferential(15%), flat(12%), and irregular(8%) type, in which false negative diagnosis was made in 1 case of crescentic and circumferential type, respectively. In 2 case of flat type and 1 case of irregular type, the differentiation between the true and false lumen was impossible with CT. The course of the false lumen in descending thoracic aorta revealed counterclock wise rotation(66%), clockwise rotation(5%) or fixed(29%) appearance. MR imaging was superior to CT in the detection of the origin of major branch vessels of the abdominal aorta. The determination of the origin of major branches of abdominal aorta arising from the true and false lumen were impossible in 2 cases in which only CT was done. Diagnosis of crescentic and circumferential types of AD with narrow and thrombosed false lumen was problematic in both CT and MR with no difference of diagnostic accuracy between the two modalities. The differentiation between the true and false lumen was difficult in flat and irregular types with only CT. Therefore, when surgical treatment is considered as in type B aortic dissection, MR imaging is recommended in order to determine the origin of major branch vessels

Validation of the Gatortail method for accurate sizing of pulmonary vessels from 3D medical images.

Science.gov (United States)

O'Dell, Walter G; Gormaley, Anne K; Prida, David A

2017-12-01

Detailed characterization of changes in vessel size is crucial for the diagnosis and management of a variety of vascular diseases. Because clinical measurement of vessel size is typically dependent on the radiologist's subjective interpretation of the vessel borders, it is often prone to high inter- and intra-user variability. Automatic methods of vessel sizing have been developed for two-dimensional images but a fully three-dimensional (3D) method suitable for vessel sizing from volumetric X-ray computed tomography (CT) or magnetic resonance imaging has heretofore not been demonstrated and validated robustly. In this paper, we refined and objectively validated Gatortail, a method that creates a mathematical geometric 3D model of each branch in a vascular tree, simulates the appearance of the virtual vascular tree in a 3D CT image, and uses the similarity of the simulated image to a patient's CT scan to drive the optimization of the model parameters, including vessel size, to match that of the patient. The method was validated with a 2-dimensional virtual tree structure under deformation, and with a realistic 3D-printed vascular phantom in which the diameter of 64 branches were manually measured 3 times each. The phantom was then scanned on a conventional clinical CT imaging system and the images processed with the in-house software to automatically segment and mathematically model the vascular tree, label each branch, and perform the Gatortail optimization of branch size and trajectory. Previously proposed methods of vessel sizing using matched Gaussian filters and tubularity metrics were also tested. The Gatortail method was then demonstrated on the pulmonary arterial tree segmented from a human volunteer's CT scan. The standard deviation of the difference between the manually measured and Gatortail-based radii in the 3D physical phantom was 0.074 mm (0.087 in-plane pixel units for image voxels of dimension 0.85 × 0.85 × 1.0 mm) over the 64 branches

Assessment of jeopardized myocardium in patients with one-vessel disease

International Nuclear Information System (INIS)

Iskandrian, A.S.; Lichtenberg, R.; Segal, B.L.; Mintz, G.S.; Mundth, E.D.; Hakki, A.-H.; Kimbiris, D.; Bemis, C.E.; Croll, M.N.; Kane, S.A.

1982-01-01

The size of the perfusion defect was assessed from a quantitative analysis of exercise thallium-201 images. Quantitative analysis was determined by measuring the area and the perimeter of the perfusion defect and expressing it as a percentage of the total left ventricular area or perimeter in three projections. Using this technique, we studied 50 patients with one-vessel disease of 50% or greater diameter narrowing. The planimetric and the perimetric methods correlated well (p<0.001, r=0.97). Of the 11 patients with less than 70% diameter narrowing, only one patient had abnormal exercise thallium-201 images. Of the remaining 39 patients with 70% or greater diameter narrowing, 35 had abnormal exercise images. The defects were larger in patients with left anterior descending coronary artery disease (33 +/- 10%; mean +/- SD by perimetry) than in patients with left circumflex coronary artery disease (19 +/- 14%, p<0.01) or right coronary artery disease (17 +/- 11%, p<0.01). There was also significant variation in the sizes of the defects in the three projections in patients with left circumflex and right coronary artery disease, but not in patients with left anterior descending coronary artery disease. Patients with left anterior descending coronary artery disease with collaterals had smaller defects than their counterparts without collaterals

Glucose transporter distribution in the vessels of the central nervous system of the axolotl Ambystoma mexicanum (Urodela: Ambystomatidae).

Science.gov (United States)

Lazzari, Maurizio; Bettini, Simone; Ciani, Franco; Franceschini, Valeria

2008-10-01

The GLUT-1 isoform of the glucose transporter is commonly considered a reliable molecular marker of blood-brain barrier endothelia in the neural vasculature organized in a three-dimensional network of single vessels. The central nervous system of the axolotl Ambystoma mexicanum is characterized by a vascular architecture that contains both single and paired vessels. The presence and distribution of the GLUT-1 transporter are studied in this urodele using both immunoperoxidase histochemistry and immunogold technique. Light microscopy reveals immunopositivity in both parenchymal and meningeal vessels. The transverse-sectioned pairs of vessels do not show the same size. Furthermore, in the same pair, the two elements often differ in diameter. The main regions of the central nervous system show a different percentage of the paired structures. Only immunogold cytochemistry reveals different staining intensity in the two adjoined elements of a vascular pair. Colloidal gold particles show an asymmetric distribution in the endothelia of both single and paired vessels. These particles are more numerous on the abluminal surface than on the luminal one. The particle density is calculated in both vascular types. The different values could indicate functional differences between single and paired vessels and between the two adjoined elements of a pair, regarding glucose transport.

Liquid entrainment and off-take through the break at the top of a vessel

International Nuclear Information System (INIS)

Kim, Chang Hyun; No, Hee Cheon

2005-01-01

In order to determine the bleed capacity of the safety depressurization system (SDS) of Advanced Power Reactor 1400 (APR1400) in the case of total loss of feed water (TLOFW), we performed an experimental study of liquid entrainment and liquid off-take from the swelled two-phase mixture surface in a vessel. A total of 220 experimental data on the entrainment and off-take are obtained using a test vessel with a height of 2.0m and an inner diameter of 0.3m and a top break with a diameter of 0.05m. Two-phase mixture levels are measured by an ultrasonic sensor within +/-1.77% with respect to the visual level data. Droplet entrainment data are obtained with and without the top break and are compared with the existing pool entrainment data. The present droplet entrainment data have higher values than the existing pool entrainment data due to (a) the pulling toward the break of the liquid deentrained on the top wall of the vessel and (b) gas acceleration in the vicinity of the break. In the present experiment, droplet entrainment, E fg , strongly depends upon j g * /h * and is proportional to the seventh power of j g * /h * in the same way as the off-take data. The empirical correlation for the onset of off-take is developed in terms of the Froude number (Fr g ) at the break and the non-dimensional inception height (h b /d). This correlation shows agreement with the present experimental data within +/-15%. The present off-take quality data show agreement with Schrock's off-take quality correlation with the rms error of 15.8%

Liquid entrainment and off-take from the two-phase mixture surface in a vessel

International Nuclear Information System (INIS)

Kim, Chang Hyun; No, Hee Cheon

2003-01-01

In order to determine the bleed capacity of the Safety Depressurization System (SDS) of Advanced Power Reactor 1400 (APR1400) in the case of Total Loss of Feed Water (TLOFW), we performed an experimental study of liquid entrainment and liquid off-take from the swelled two-phase mixture surface in a vessel. A total of 220 experimental data on the entrainment and off-take are obtained using a test vessel with a height of 2.0m and an inner diameter of 0.3m, and a top break with a diameter of 0.05m. Two-phase mixture levels are measured by an ultrasonic sensor within ±1.77% with respect to the visual level data. Droplet entrainment data are obtained with and without the top break and are compared with the existing pool entrainment data. The present droplet entrainment data have higher values than those of the existing pool entrainment due to (a) the pulling toward the break of the liquid deentrained on the top wall of the vessel and (b) gas acceleration in the vicinity of the break. In the present experiment, droplet entrainment, Efg, strongly depends upon jg/h and is proportional to the 7th power of jg/h in the same way as the off-take data. The empirical correlation for the onset of off-take is developed in terms of the Froude number (Frg) at the break and the non-dimensional inception height (hb/d). This correlation shows agreement with the present experimental data within ±15%. The present off-take quality data show agreement with Schrock's off-take quality correlation with the r.m.s. error of 15.8%

Influence of the weighing bar position in vessel on measurement of cement’s particle size distribution by using the buoyancy weighing-bar method

Science.gov (United States)

Tambun, R.; Sihombing, R. O.; Simanjuntak, A.; Hanum, F.

2018-02-01

The buoyancy weighing-bar method is a new simple and cost-effective method to determine the particle size distribution both settling and floating particle. In this method, the density change in a suspension due to particle migration is measured by weighing buoyancy against a weighing-bar hung in the suspension, and then the particle size distribution is calculated using the length of the bar and the time-course change in the mass of the bar. The apparatus of this method consists of a weighing-bar and an analytical balance with a hook for under-floor weighing. The weighing bar is used to detect the density change in suspension. In this study we investigate the influences of position of weighing bar in vessel on settling particle size distribution measurements of cement by using the buoyancy weighing-bar method. The vessel used in this experiment is graduated cylinder with the diameter of 65 mm and the position of weighing bar is in center and off center of vessel. The diameter of weighing bar in this experiment is 10 mm, and the kerosene is used as a dispersion liquids. The results obtained show that the positions of weighing bar in vessel have no significant effect on determination the cement’s particle size distribution by using buoyancy weighing-bar method, and the results obtained are comparable to those measured by using settling balance method.

Estimation and tracking of AP-diameter of the inferior vena cava in ultrasound images using a novel active circle algorithm.

Science.gov (United States)

Karami, Ebrahim; Shehata, Mohamed S; Smith, Andrew

2018-05-04

Medical research suggests that the anterior-posterior (AP)-diameter of the inferior vena cava (IVC) and its associated temporal variation as imaged by bedside ultrasound is useful in guiding fluid resuscitation of the critically-ill patient. Unfortunately, indistinct edges and gaps in vessel walls are frequently present which impede accurate estimation of the IVC AP-diameter for both human operators and segmentation algorithms. The majority of research involving use of the IVC to guide fluid resuscitation involves manual measurement of the maximum and minimum AP-diameter as it varies over time. This effort proposes using a time-varying circle fitted inside the typically ellipsoid IVC as an efficient, consistent and novel approach to tracking and approximating the AP-diameter even in the context of poor image quality. In this active-circle algorithm, a novel evolution functional is proposed and shown to be a useful tool for ultrasound image processing. The proposed algorithm is compared with an expert manual measurement, and state-of-the-art relevant algorithms. It is shown that the algorithm outperforms other techniques and performs very close to manual measurement. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

Joshi, Vinayak S; Reinhardt, Joseph M; Garvin, Mona K; Abramoff, Michael D

2014-01-01

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%.

Ultrasonic testing of electron beam closure weld on pressure vessel

International Nuclear Information System (INIS)

Andrews, R.W.

1975-01-01

One of the special products manufactured at the General Electric Neutron Devices Department (GEND) is a small stainless steel vessel designed to hold a component under high pressure for long periods. The vessel is a thick-walled cylinder with a threaded receptacle into which a plug is screwed and welded after receiving the unit to be tested. The test cavity is then pressurized through a small diameter opening in the bottom and that opening is welded closed. When x-ray inspection techniques did not reveal defective welds at the threaded plug in a pressured vessel, occasional ''leakers'' occurred. With normal equipment tolerances, the electron beam spike tends to wander from the desired path, particularly at the root of the weld. Ultrasonic techniques were used to successfully inspect the weld. The testing technique is based on the observation that ultrasonic energy is reflected from the unwelded screw threads and not from the regions where the threads are completely fused together by welding. Any gas pore or any threaded region outside the weld bead can produce an echo. The units are rotated while the ultrasonic transducer travels in a direction parallel to the axis of rotation and toward the welded end. This produces a helical scan which is converted to a two-dimensional presentation in which incomplete welds can be noted. (U.S.)

Utilization of self-expanding stents in the treatment of intracranial atherosclerotic disease in the distal small cerebral vessels

International Nuclear Information System (INIS)

Turk, Aquilla S.; Niemann, David B.; Aagaard-Kienitz, Beverly; Ahmed, Azam; Brooks, Nathaniel; Levine, Ross L.

2007-01-01

Previously, endovascular treatment of stenosis related to intracranial atherosclerosis (ICAD) involving arteries measuring less than 2 mm in diameter was limited. To our knowledge, there are no reports in the literature addressing stent placement for treatment of stenosis in arteries of this size. Four patients aged 33 to 80 years (mean 57.5 years) with medically refractory ICAD underwent angioplasty and stenting of small (<2 mm) distal intracerebral arteries. Vessel location and length of follow-up were anterior cerebral artery (ACA) A1 segment (5 months), ACA A2 segment (18 months), middle cerebral artery M1 segment (18 months), and posterior cerebral artery P1 segment (8 months) with vessel calibers ranging from 1.2 to 1.8 mm. Clinical and imaging follow-up ranged from 5 to 18 months. All procedures were successfully performed without complications. Follow-up out to 18 months demonstrated one vessel that went on to occlusion while the other stented vessel segments remained patent. One patient died 8 months after stenting, but the death was not related to neurological disease. The remaining patients experienced resolution of the presenting symptomatology and remained asymptomatic throughout follow-up. In this small series, stenoses of distal (<2 mm) cerebral arteries were amenable to treatment using new self-expanding stents. We safely and successfully treated four arteries smaller than 2 mm in diameter with newer self-expanding stents. All patients remained clinically asymptomatic. One stent occluded at 5 months and the others remained patent during follow-up. Longer term clinical follow-up is required to determine the durability and viability of this therapy. (orig.)

LOCAL VELOCITY PROFILES MEASURED BY PIV IN AN VESSEL AGITATED BY RUSHTON TURBINE

Directory of Open Access Journals (Sweden)

Radek Šulc

2014-12-01

Full Text Available The hydrodynamics and flow field were measured in an agitated vessel using 2-D Time Resolved Particle Image Velocimetry (2-D TR PIV. The experiments were carried out in a fully baffled cylindrical flat bottom vessel 300 mm in inner diameter. The tank was agitated by a Rushton turbine 100 mm in diameter. The velocity fields were measured for three impeller rotation speeds 300 rpm, 450 rpm and 600 rpm and the corresponding Reynolds numbers in the range 50 000 < Re < 100 000, which means that the fully-developed turbulent flow was reached. In accordance with the theory of mixing, the dimensionless mean and fluctuation velocities in the measured directions were found to be constant and independent of the impeller rotational speed. The velocity profiles were averaged, and were expressed by Chebyshev polynomials of the 1st order. Although the experimentally investigated area was relatively far from the impeller, and it was located in upward flow to the impeller, no state of local isotropy was found. The ratio of the axial rms fluctuation velocity to the radial component was found to be in the range from 0.523 to 0.768. The axial turbulence intensity was found to be in the range from 0.293 to 0.667, which corresponds to a high turbulence intensity.

Diameter-speed relation of sprite streamers

International Nuclear Information System (INIS)

Kanmae, T; Stenbaek-Nielsen, H C; McHarg, M G; Haaland, R K

2012-01-01

Propagation and splitting of sprite streamers has been observed at high temporal and spatial resolution using two intensified high-speed CMOS cameras recording at 10 000 and 16 000 frames per second. Concurrent video recordings from a remote site provided data for triangulation allowing us to determine accurate altitude scales for the sprites. Diameters and speeds of the sprite streamers were measured from the high-speed images, and the diameters were scaled to the reduced diameters based on the triangulated locations. The sprite streamers with larger reduced diameter move faster than those with smaller diameter; the relation between the reduced diameter and speed is roughly linear. The reduced diameters at ≈65-70 km altitude are larger than streamer diameters measured at ground pressure in laboratory discharges indicating a deviation from the similarity law possibly due to the effects of the photoionization and an expansion of the streamer head along its propagation over a long distance. The reduced diameter and speed of the sprite streamers agree well with the diameter-velocity relation proposed by Naidis (2009 Phys. Rev. E 79 057401), and the peak electric field of the sprite streamers is estimated to be approximately 3-5 times the breakdown threshold field. (paper)

Pressure vessel for nuclear reactor plant consisting of several pre-stressed cast pressure vessels

International Nuclear Information System (INIS)

Bodmann, E.

1984-01-01

Several cylindrical pressure vessel components made of pressure castings are arranged on a sector of a circle around the cylindrical cast pressure vessel for accommodating the helium cooled HTR. Each component pressure vessel is connected to the reactor vessel by a horizontal gas duct. The contact surfaces between reactor and component pressure vessel are in one plane. In the spaces between the individual component pressure vessels, there are supporting blocks made of cast iron, which are hollow and also have flat surfaces. With the reactor vessel and the component pressure vessels they form a disc-shaped connecting part below and above the gas ducts. (orig./PW)

Retinal Photoreceptors and Microvascular Changes in Prediabetes Measured with Adaptive Optics (rtx1™: A Case-Control Study

Directory of Open Access Journals (Sweden)

Anna Zaleska-Żmijewska

2017-01-01

Full Text Available Background. Patients with prediabetes are at risk for diabetes, cardiovascular events, and microvascular complications. The rtx1 (Imagine Eyes, France permits early detection of changes in the retinal photoreceptors and vessels. Objective. Cone parameters and retinal microvasculature were analyzed with the rtx1 in 12 prediabetic patients and 22 healthy subjects. The analysis was based on cone density (DM, interphotoreceptor distance (SM, cone packing regularity, and retinal vessel parameters: wall thickness, lumen diameter (LD, wall-to-lumen ratio (WLR, and cross-sectional area of the vascular wall. Results. DM in the prediabetic group was not significantly lower than that in the control group (18,935 ± 1713 cells/mm2 and 19,900 ± 2375 cells/mm2, respectively; p=0.0928. The LD and WLR means differed significantly between the prediabetic and the control groups (LD 94.3 ± 10.9 versus 101.2 ± 15, p=0.022; WLR 0.29 ± 0.05 versus 0.22 ± 0.03, p<0.05. A multivariate regression analysis showed that the WLR was significantly correlated with BMI and total cholesterol. Conclusions. Abnormalities found in rtx1 examinations indicated early signs of arteriolar dysfunction, prior to impaired glucose tolerance progressing to diabetes. The rtx1 retinal image analysis offers noninvasive measurement of early changes in the vasculature that routine clinical examination cannot detect.

Evaluation of Directional Atherectomy Studied by Intravascular Ultrasound in Femoropopliteal Artery Stenosis

International Nuclear Information System (INIS)

Tielbeek, Alexander V.; Vroegindeweij, Dammis; Gussenhoven, Elma J.; Buth, Jacob; Landman, Guido H.M.

1997-01-01

Purpose: To evaluate the role of intravascular ultrasound (IVUS) before and after directional atherectomy (DA) in the treatment of femoropopliteal artery stenosis. Methods: In 12 patients with 16 stenoses IVUS was performed before and immediately after an angiographically successful DA. This was defined as a diameter reduction (DR) ≤ 50%, which was calculated using the minimal lumen diameter compared with the diameter of a nearby 'normal' segment. In the presence of residual plaque on IVUS an additional DA was performed. Endpoints studied were DR ≤ 30% on IVUS compared with the IVUS findings of the angiographically normal reference segment, or when no additional atherosclerotic material could be removed by further DA passages. Results: Additional DA (mean 1.6 per lesion) had to be performed in all patients. Initial DA increased the cross-sectional free lumen area (FLA) from 3.8 ± 2.0 mm 2 to 8.1 ± 2.7 mm 2 (p= 0.0004). Additional DA increased FLA to 9.3 ± 2.3 mm 2 (p= 0.002) after the second passage and to 9.8 ± 2.4 mm 2 (p= 0.09) after the final DA run. The plaque area (PLA) before DA decreased from 18.1 ± 4.2 mm 2 to 15.4 ± 4.8 mm 2 (p= 0.002) after the first passage, and to 13.5 ± 5.0 mm 2 (p= 0.004) and 12.8 ± 4.4 mm 2 (p= 0.07) after the second and final DA runs, respectively. PLA of the reference segment (9.5 ± 5.7 mm 2 ) was significantly smaller (p= 0.006) than the final PLA of the treated lesion, indicating a large amount of retained plaque. As a result of DA there was an increase in the area bordered by the medial layer, i.e., the total vessel area (from 21.9 ± 4.7 mm 2 to 23.0 ± 4.7 mm 2 ), significantly in eccentric and soft lesions. On IVUS, dissection and plaque rupture after the final passage was seen in 12 of 16 stenoses; two dissections were seen on the completion angiogram. After the final passage in all stenoses except three, the DR with IVUS was ≤ 30%. Conclusion: Lumen enlargement following DA is predominantly due to plaque

Evidence of Flicker-Induced Functional Hyperaemia in the Smallest Vessels of the Human Retinal Blood Supply.

Directory of Open Access Journals (Sweden)

Angelina Duan

Full Text Available Regional changes in blood flow are initiated within neural tissue to help fuel local differences in neural activity. Classically, this response was thought to arise only in larger arterioles and venules. However, recently, it has been proposed that a the smallest vessels of the circulation make a comparable contribution, and b the response should be localised intermittently along such vessels, due to the known distribution of contractile mural cells. To assess these hypotheses in human neural tissue in vivo, we imaged the retinal microvasculature (diameters 3-28 μm non-invasively, using adaptive optics, before and after delivery of focal (360 μm patches of flickering visible light. Our results demonstrated a definite average response in 35% of all vessel segments analysed. In these responding vessels, the magnitude of proportional dilation (mean ± SEM for pre-capillary arterioles 13 ± 5%, capillaries 31 ± 8%, and post-capillary venules 10 ± 3% is generally far greater than the magnitudes we and others have measured in the larger retinal vessels, supporting proposition a above. The dilations observed in venules were unexpected based on previous animal work, and may be attributed either to differences in stimulus or species. Response heterogeneity across the network was high; responses were also heterogeneous along individual vessels (45% of vessel segments showed demonstrable locality in their response. These observations support proposition b above. We also observed a definite average constriction across 7% of vessel segments (mean ± SEM constriction for capillaries -16 ± 3.2%, and post-capillary venules -18 ± 12%, which paints a picture of dynamic redistribution of flow throughout the smallest vessel networks in the retina in response to local, stimulus-driven metabolic demand.

Probabilistic retinal vessel segmentation

Science.gov (United States)

Wu, Chang-Hua; Agam, Gady

2007-03-01

Optic fundus assessment is widely used for diagnosing vascular and non-vascular pathology. Inspection of the retinal vasculature may reveal hypertension, diabetes, arteriosclerosis, cardiovascular disease and stroke. Due to various imaging conditions retinal images may be degraded. Consequently, the enhancement of such images and vessels in them is an important task with direct clinical applications. We propose a novel technique for vessel enhancement in retinal images that is capable of enhancing vessel junctions in addition to linear vessel segments. This is an extension of vessel filters we have previously developed for vessel enhancement in thoracic CT scans. The proposed approach is based on probabilistic models which can discern vessels and junctions. Evaluation shows the proposed filter is better than several known techniques and is comparable to the state of the art when evaluated on a standard dataset. A ridge-based vessel tracking process is applied on the enhanced image to demonstrate the effectiveness of the enhancement filter.

Molecular cloning and expression of cDNA encoding a lumenal calcium binding glycoprotein from sarcoplasmic reticulum

International Nuclear Information System (INIS)

Leberer, E.; Charuk, J.H.M.; MacLennan, D.H.; Green, N.M.

1989-01-01

Antibody screening was used to isolate a cDNA encoding the 160-kDa glycoprotein of rabbit skeletal muscle sarcoplasmic reticulum. The cDNA is identical to that encoding the 53-kDa glycoprotein except that it contains an in-frame insertion of 1,308 nucleotides near its 5' end, apparently resulting from alternative splicing. The protein encoded by the cDNA would contain a 19-residue NH 2 -terminal signal sequence and a 453-residue COOH-terminal sequence identical to the 53-kDa glycoprotein. It would also contain a 436-amino acid insert between these sequences. This insert would be highly acidic, suggesting that it might bind Ca 2+ . The purified 160-kDa glycoprotein and the glycoprotein expressed in COS-1 cells transfected with cDNA encoding the 160-kDa glycoprotein were shown to bind 45 C 2+ in a gel overlay assay. The protein was shown to be located in the lumen of the sarcoplasmic reticulum and to be associated through Ca 2+ with the membrane. The authors propose that this lumenal Ca 2+ binding glycoprotein of the sarcoplasmic reticulum be designated sarcalumenin