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Sample records for venous wedge angiogram

  1. Evaluation of portal hypertension: a comparison of the use of liver perfusion CT with wedge hepatic venous pressure and hepatic

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Dong Jin; Kim, Young Joong; Park, Yong Sung; Lee, Tae Hee [University of Konyang College of Medicine, Daejeon (Korea, Republic of); Kim, Chong Soo; Kang, Heung Keun [Chonbuk National University Medical School, Jeonju (Korea, Republic of)

    2008-09-15

    We compared the hepatic perfusion indices obtained using hepatic perfusion CT with the wedge hepatic venous pressure (WHVP) and hepatic venous pressure gradient (HVPG) to determine the efficacy of the use of liver perfusion CT for the evaluation of portal hypertension. Thirty-five patients with liver cirrhosis underwent hepatic vein catheterization to measure WHVP and HVPG and underwent a liver perfusion CT examination. Arterial perfusion, portal perfusion, total perfusion and the hepatic perfusion index (HPI) were calculated by the methods described by Miles and Blomlely. The overall correlation coefficients (r) between the perfusion indices and WHVP and HVPG were calculated. An additional correlation coefficient of 23 alcoholic cirrhosis patients was calculated. Using Blomley's equation, HPI had a positive correlation with WHVP (r = .471; {rho} < .05) and HVPG (r = .482; {rho} < .05). For the alcoholic liver cirrhosis patients, HPI had a higher positive correlation with WHVP (r = .500; {rho} < .05) and HVPG (r = .539; {rho} < .05) than for the non-alcoholic cirrhosis patients. There was no statistical difference between the use of Miles' equation and Blomley's equation for the evaluation of portal hypertension. This preliminary study showed that HPI positively correlated with WHVP and HVPG, especially in alcoholic cirrhosis patients. Liver perfusion CT may be useful in the evaluation of portal hypertension.

  2. Fake Wedges

    OpenAIRE

    Klein, John R.; Peter, John W.

    2012-01-01

    A fake wedge is a diagram of spaces K C whose double mapping cylinder is contractible. The terminology stems from the special case A = K v C with maps given by the projections. In this paper, we study the homotopy type of the moduli space D(K,C) of fake wedges on K and C. We formulate two conjectures concerning this moduli space and verify that these conjectures hold after looping once. We show how embeddings of manifolds in Euclidean space provide a wealth of examples of non-trivial fake we...

  3. Radial wedge flange clamp

    Science.gov (United States)

    Smith, Karl H.

    2002-01-01

    A radial wedge flange clamp comprising a pair of flanges each comprising a plurality of peripheral flat wedge facets having flat wedge surfaces and opposed and mating flat surfaces attached to or otherwise engaged with two elements to be joined and including a series of generally U-shaped wedge clamps each having flat wedge interior surfaces and engaging one pair of said peripheral flat wedge facets. Each of said generally U-shaped wedge clamps has in its opposing extremities apertures for the tangential insertion of bolts to apply uniform radial force to said wedge clamps when assembled about said wedge segments.

  4. Digital image processing of vascular angiograms

    Science.gov (United States)

    Selzer, R. H.; Beckenbach, E. S.; Blankenhorn, D. H.; Crawford, D. W.; Brooks, S. H.

    1975-01-01

    The paper discusses the estimation of the degree of atherosclerosis in the human femoral artery through the use of a digital image processing system for vascular angiograms. The film digitizer uses an electronic image dissector camera to scan the angiogram and convert the recorded optical density information into a numerical format. Another processing step involves locating the vessel edges from the digital image. The computer has been programmed to estimate vessel abnormality through a series of measurements, some derived primarily from the vessel edge information and others from optical density variations within the lumen shadow. These measurements are combined into an atherosclerosis index, which is found in a post-mortem study to correlate well with both visual and chemical estimates of atherosclerotic disease.

  5. Rethinking wedges

    Science.gov (United States)

    Davis, Steven J.; Cao, Long; Caldeira, Ken; Hoffert, Martin I.

    2013-03-01

    Abstract Stabilizing CO2 emissions at current levels for fifty years is not consistent with either an atmospheric CO2 concentration below 500 ppm or global temperature increases below 2 °C. Accepting these targets, solving the climate problem requires that emissions peak and decline in the next few decades, and ultimately fall to near zero. Phasing out emissions over 50 years could be achieved by deploying on the order of 19 'wedges', each of which ramps up linearly over a period of 50 years to ultimately avoid 1 GtC y-1 of CO2 emissions. But this level of mitigation will require affordable carbon-free energy systems to be deployed at the scale of tens of terawatts. Any hope for such fundamental and disruptive transformation of the global energy system depends upon coordinated efforts to innovate, plan, and deploy new transportation and energy systems that can provide affordable energy at this scale without emitting CO2 to the atmosphere. 1. Introduction In 2004, Pacala and Socolow published a study in Science arguing that '[h]umanity can solve the carbon and climate problem in the first half of this century simply by scaling up what we already know how to do' [1]. Specifically, they presented 15 options for 'stabilization wedges' that would grow linearly from zero to 1 Gt of carbon emissions avoided per year (GtC y-1 1 Gt = 1012 kg) over 50 years. The solution to the carbon and climate problem, they asserted, was 'to deploy the technologies and/or lifestyle changes necessary to fill all seven wedges of the stabilization triangle'. They claimed this would offset the growth of emissions and put us on a trajectory to stabilize atmospheric CO2 concentration at 500 ppm if emissions decreased sharply in the second half of the 21st century. The wedge concept has proven popular as an analytical tool for considering the potential of different technologies to reduce CO2 emissions. In the years since the paper was published, it has been cited more than 400 times, and

  6. Brain dead or not? CT angiogram yielding false-negative result on brain death confirmation.

    Science.gov (United States)

    Johnston, Robyn; Kaliaperumal, Chandrasekaran; Wyse, Gerald; Kaar, George

    2013-01-08

    We describe a case of severe traumatic brain injury with multiple facial and skull fractures where CT angiogram (CTA) failed to yield a definite result of brain death as an ancillary test. A 28-year-old man was admitted following a road traffic accident with a Glasgow Coma Score (GCS) of 3/15 and fixed pupils. CT brain revealed uncal herniation and diffuse cerebral oedema with associated multiple facial and skull fractures. 72 h later, his clinical condition remained the same with high intracranial pressure refractory to medical management. Clinical confirmation on brain death was not feasible owing to facial injuries. A CTA, performed to determine brain perfusion, yielded a 'false-negative' result. Skull fractures have possibly led to venous prominence in the cortical and deep venous drainage system. This point needs to be borne in mind while considering CTA as an ancillary test to confirm brain death.

  7. Congenital pseudoarthrosis associated with venous malformation

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hadidy, A.; Haroun, A.; Al-Ryalat, N. [Jordan University Hospital, Radiology Department, P.O. Box 340621, Amman (Jordan); Hamamy, H. [Endocrinology and Genetics, National Center for Diabetes, Amman (Jordan); Al-Hadidi, S. [Jordan University Hospital, Departments of Orthopedics, Amman (Jordan)

    2007-06-15

    Congenital pseudoarthrosis is a pathologic entity that may be isolated, or may be associated with neurofibromatosis. We report the case of a 3-year-old female with congenital pseudoarthrosis involving the right tibia and fibula. Magnetic resonance imaging (MRI) and complementary magnetic resonance angiogram (MRA) revealed a lobulated mass with vivid enhancement, which led to the diagnosis of venous malformation. This is the first report of congenital pseudoarthrosis caused by the presence of a vascular malformation. (orig.)

  8. Wedged multilayer Laue lens

    Science.gov (United States)

    Conley, Ray; Liu, Chian; Qian, Jun; Kewish, Cameron M.; Macrander, Albert T.; Yan, Hanfei; Kang, Hyon Chol; Maser, Jörg; Stephenson, G. Brian

    2008-05-01

    A multilayer Laue lens (MLL) is an x-ray focusing optic fabricated from a multilayer structure consisting of thousands of layers of two different materials produced by thin-film deposition. The sequence of layer thicknesses is controlled to satisfy the Fresnel zone plate law and the multilayer is sectioned to form the optic. An improved MLL geometry can be created by growing each layer with an in-plane thickness gradient to form a wedge, so that every interface makes the correct angle with the incident beam for symmetric Bragg diffraction. The ultimate hard x-ray focusing performance of a wedged MLL has been predicted to be significantly better than that of a nonwedged MLL, giving subnanometer resolution with high efficiency. Here, we describe a method to deposit the multilayer structure needed for an ideal wedged MLL and report our initial deposition results to produce these structures.

  9. Shock detachment from curved wedges

    Science.gov (United States)

    Mölder, S.

    2017-09-01

    Curved shock theory is used to show that the flow behind attached shocks on doubly curved wedges can have either positive or negative post-shock pressure gradients depending on the freestream Mach number, the wedge angle and the two wedge curvatures. Given enough wedge length, the flow near the leading edge can choke to force the shock to detach from the wedge. This local choking can preempt both the maximum deflection and the sonic criteria for shock detachment. Analytical predictions for detachment by local choking are supported by CFD results.

  10. Hepatic hemangioma with normal angiograms: Three case reports

    Energy Technology Data Exchange (ETDEWEB)

    Davis, W.D.; Ferrante, W.A.; Tutton, R.H.; Bowen, J.C. (Ochsner Clinic and Alton Ochsner Medical Foundation, New Orleans, LA (USA))

    1990-02-16

    Three cases of symptomatic cavernous hemangioma of the liver are reported. All three patients have normal angiograms. A review of the literature shows that the diagnosis of hemangioma may be made noninvasively with a high degree of accuracy. Technetium Tc 99m-labeled red blood cell scanning is very specific, while dynamic computed tomography may be more sensitive for small lesions. A combination of the two modalities makes the diagnosis in greater than 90% of cases. Magnetic resonance imaging is also sensitive and specific. Angiography, as shown in these cases, may not only be questionably indicated, but may be misleading. The treatment for symptomatic lesions is resection, and secondary alternatives are discussed.

  11. [Venous ulcer].

    Science.gov (United States)

    Böhler, Kornelia

    2016-06-01

    Venous disorders causing a permanent increase in venous pressure are by far the most frequent reason for ulcers of the lower extremity. With a prevalence of 1 % in the general population rising to 4 % in the elderly over 80 and its chronic character, 1 % of healthcare budgets of the western world are spent on treatment of venous ulcers. A thorough investigation of the underlying venous disorder is the prerequisite for a differenciated therapy. This should comprise elimination of venous reflux as well as local wound management. Chronic ulcers can successfully be treated by shave therapy and split skin grafting. Compression therapy is a basic measure not only in venous ulcer treatment but also in prevention of ulcer recurrence. Differential diagnosis which have to be considered are arterial ulcers, vasculitis and neoplasms.

  12. Surgical management of scalp arterio-venous malformation and scalp venous malformation: An experience of eleven cases

    Directory of Open Access Journals (Sweden)

    Forhad Hossain Chowdhury

    2013-01-01

    Full Text Available Aims: Scalp arterio-venous malformation (AVM and scalp venous malformation (SVM are rare conditions that usually need surgical treatment. Here, we have reported our experience of the surgical management of such lesions with a short review of the literature. Materials and Methods: In this prospective study, 11 patients with scalp AVM and SVM, who underwent surgical excision of lesion in our hospital from 2006 to 2012, were included. All suspected high-flow AVM were investigated with the selective internal and external carotid digital subtraction angiogram (DSA ± computed tomography (CT scan of brain with CT angiogram or magnetic resonance imaging (MRI of brain with MR angiogram, and all suspected low-flow vascular malformation (VM was investigated with MRI of brain + MR angiogram. Eight were high-flow and three were low-flow VM. Results: All lesions were successfully excised. Scalp cosmetic aspects were acceptable in all cases. There was no major post-operative complication or recurrence till last follow-up. Conclusions: With preoperative appropriate surgical planning, scalp AVM and SVM can be excised without major complication.

  13. Characterization of wedge waves propagating along wedge tips with defects.

    Science.gov (United States)

    Chen, Ming-I; Tesng, Seng-Po; Lo, Pei-Yuan; Yang, Che-Hua

    2018-01-01

    Wedge waves are guided acoustic waves propagating along the tip of a wedge with the energy tightly confined near the wedge. Anti-symmetric flexural (ASF) modes are wedge waves with their particle motion anti-symmetric with the apex mid-plane. This study investigates the behaviors of ASF modes propagation along wedge tips with perfect and imperfect rectangular defects. Numerical finite element simulations and experimental measurements using a laser ultrasound technique are employed to explore the behaviors of ASF modes interacting with defects. Complex reflections and transmissions involved with direct reflections and transmissions as well as the newly discovered mode conversions will be explored and quantified in numerical as well as experimental ways. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. The value of MRI in angiogram-negative intracranial haemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Renowden, S.A. (Dept. of Neuroradiology, Radcliffe Infirmary, Oxford (United Kingdom)); Molyneux, A.J. (Dept. of Neuroradiology, Radcliffe Infirmary, Oxford (United Kingdom)); Anslow, P. (Dept. of Neuroradiology, Radcliffe Infirmary, Oxford (United Kingdom)); Byrne, J.V. (Dept. of Neuroradiology, Radcliffe Infirmary, Oxford (United Kingdom))

    1994-08-01

    In one year, cerebral angiograms were performed for intracranial haemorrhage (ICH) on 334 patients. No cause for haemorrhage could be identified in 41 (12 %), 30 of whom had predominantly subarachnoid (SAH) and 11 predominantly parenchymal haemorrhage (PH). These patients were prospectively examined by cranial MRI 1-6 weeks after the ictus. The MRI studies were positive in 7 patients (17 %). In the 30 patients examined after SAH, 2 studies were positive, showing an aneurysm in one case and a brain stem lesion of uncertain aetiology in the other. In those examined after PH, cavernous angiomas were shown in 2, a tumour in 1 and a vascular malformation in another; useful diagnostic information was thus obtained in 36 % of this group. (orig.)

  15. Outcome Following a Negative CT Angiogram for Gastrointestinal Hemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Victoria, E-mail: drvictoriac@gmail.com; Tse, Donald, E-mail: donald.tse@gmail.com; Dixon, Shaheen, E-mail: shaheen7noorani@gmail.com [John Radcliffe Hospital, Department of Radiology, Level 2 (United Kingdom); Shrivastava, Vivek, E-mail: vivshriv@yahoo.com [Hull Royal Infirmary, Department of Radiology (United Kingdom); Bratby, Mark, E-mail: mark.bratby@ouh.nhs.uk; Anthony, Suzie, E-mail: suzie.anthony@ouh.nhs.uk; Patel, Rafiuddin, E-mail: rafiuddin.patel@ouh.nhs.uk; Tapping, Charles, E-mail: charles.tapping@ouh.nhs.uk; Uberoi, Raman, E-mail: raman.uberoi@orh.nhs.uk [John Radcliffe Hospital, Department of Radiology, Level 2 (United Kingdom)

    2015-04-15

    ObjectiveThis study was designed to evaluate the role of a negative computed tomography angiogram (CTA) in patients who present with gastrointestinal (GI) hemorrhage.MethodsA review of all patients who had CTAs for GI hemorrhage over an 8-year period from January 2005 to December 2012 was performed. Data for patient demographics, location of hemorrhage, hemodynamic stability, and details of angiograms and/or the embolization procedure were obtained from the CRIS/PACS database, interventional radiology database, secure electronic medical records, and patient’s clinical notes.ResultsA total of 180 patients had 202 CTAs during the 8-year period: 87 CTAs were performed for upper GI hemorrhage (18 positive for active bleeding, 69 negative) and 115 for lower GI hemorrhage (37 positive for active bleeding, 78 negative); 58.7 % (37/63) of patients with upper GI bleed and 77.4 % (48/62) of patients with lower GI bleed who had an initial negative CTA did not rebleed without the need for radiological or surgical intervention. This difference was statistically significant (p = 0.04). The relative risk of rebleeding, following a negative CTA, in lower GI bleeding versus upper GI bleeding patients is 0.55 (95 % confidence interval 0.32–0.95).ConclusionsPatients with upper GI bleed who had negative CTAs usually require further intervention to stop the bleeding. In contrast, most patients presenting with lower GI hemorrhage who had a negative first CTA were less likely to rebleed.

  16. A Workflow for Patient-Individualized Virtual Angiogram Generation Based on CFD Simulation

    Directory of Open Access Journals (Sweden)

    Jürgen Endres

    2012-01-01

    Full Text Available Increasing interest is drawn on hemodynamic parameters for classifying the risk of rupture as well as treatment planning of cerebral aneurysms. A proposed method to obtain quantities such as wall shear stress, pressure, and blood flow velocity is to numerically simulate the blood flow using computational fluid dynamics (CFD methods. For the validation of those calculated quantities, virtually generated angiograms, based on the CFD results, are increasingly used for a subsequent comparison with real, acquired angiograms. For the generation of virtual angiograms, several patient-specific parameters have to be incorporated to obtain virtual angiograms which match the acquired angiograms as best as possible. For this purpose, a workflow is presented and demonstrated involving multiple phantom and patient cases.

  17. Sojourner at Wedge

    Science.gov (United States)

    1997-01-01

    This image, taken by the Imager for Mars Pathfinder (IMP) at the end of Sol 44, shows the Sojourner rover heading toward a rock called 'Shark.' Sojourner's left front wheel is jutting up against the side of Wedge, at left. The stowed Alpha Proton X-Ray Spectrometer (APXS) instrument can be seen on the rear on the rover.Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is a division of the California Institute of Technology (Caltech).

  18. Predictive value of symptoms, signs and biomarkers on computed tomography pulmonary angiogram results.

    Science.gov (United States)

    Sethwala, Anver; Wang, Xiaojie; Sturm, Emma E; Collins, Kate L; O'Donnabhain, Ronan; Friedman, Nadia D

    2018-01-01

    Pulmonary embolism (PE) is associated with significant morbidity and mortality. PE is a heterogeneous entity that causes a wide variety of clinical presentations, making it imperative to establish which clinical symptoms, signs and biomarkers can influence the pretest probability of PE to aid clinicians and reduce over testing. To analyse the clinical parameters used by clinicians to order a computed tomography pulmonary angiogram (CTPA) and establish which were associated with the presence of PE. Medical records of patients who underwent CTPA from December 2015 to March 2016 were extracted. Patient demographics, clinical symptoms, diagnostic and radiological results were analysed. The study included 150 CTPA studies. Of the studies, 25 were positive for PE and 125 were negative. There was no significant relationship between the presence or character of chest pain and a positive CTPA result (P = 0.216). Previous history of venous thromboembolism (VTE) (P < 0.0001), one or more risk factors for VTE and positive troponin (P < 0.002) were all predictive of PE. None of the patients with a negative D-dimer had a positive CTPA. This study supports the negative predictive value of the D-dimer for excluding PE and demonstrates that the strongest pretest predictors of PE in our population are a prior history of VTE, risk factors for VTE and elevated troponin. None of the parameters that often generate requests for CTPA, including vital signs or the presence of chest pain, was associated with the presence of PE in our study population. © 2017 Royal Australasian College of Physicians.

  19. Venous Ulcers

    Science.gov (United States)

    Caprini, J.A.; Partsch, H.; Simman, R.

    2013-01-01

    Venous leg ulcers are the most frequent form of wounds seen in patients. This article presents an overview on some practical aspects concerning diagnosis, differential diagnosis and treatment. Duplex ultrasound investigations are essential to ascertain the diagnosis of the underlying venous pathology and to treat venous refluxes. Differential diagnosis includes mainly other vascular lesions (arterial, microcirculatory causes), hematologic and metabolic diseases, trauma, infection, malignancies. Patients with superficial venous incompetence may benefit from endovenous or surgical reflux abolition diagnosed by Duplex ultrasound. The most important basic component of the management is compression therapy, for which we prefer materials with low elasticity applied with high initial pressure (short-stretch bandages and Velcro-strap devices). Local treatment should be simple, absorbing and not sticky dressings keeping adequate moisture balance after debridement of necrotic tissue and biofilms are preferred. After the ulcer is healed compression therapy should be continued in order to prevent recurrence. PMID:26236636

  20. Interpretation of Coronary Angiograms Recorded Using Google Glass: A Comparative Analysis.

    Science.gov (United States)

    Duong, Thao; Wosik, Jedrek; Christakopoulos, Georgios E; Martínez Parachini, José Roberto; Karatasakis, Aris; Tarar, Muhammad Nauman Javed; Resendes, Erica; Rangan, Bavana V; Roesle, Michele; Grodin, Jerrold; Abdullah, Shuaib M; Banerjee, Subhash; Brilakis, Emmanouil S

    2015-10-01

    Google Glass (Google, Inc) is a voice-activated, hands-free, optical head-mounted display device capable of taking pictures, recording videos, and transmitting data via wi-fi. In the present study, we examined the accuracy of coronary angiogram interpretation, recorded using Google Glass. Google Glass was used to record 15 angiograms with 17 major findings and the participants were asked to interpret those recordings on: (1) an iPad (Apple, Inc); or (2) a desktop computer. Interpretation was compared with the original angiograms viewed on a desktop. Ten physicians (2 interventional cardiologists and 8 cardiology fellows) participated. One point was assigned for each correct finding, for a maximum of 17 points. The mean angiogram interpretation score for Google Glass angiogram recordings viewed on an iPad or a desktop vs the original angiograms viewed on a desktop was 14.9 ± 1.1, 15.2 ± 1.8, and 15.9 ± 1.1, respectively (P=.06 between the iPad and the original angiograms, P=.51 between the iPad and recordings viewed on a desktop, and P=.43 between the recordings viewed on a desktop and the original angiograms). In a post-study survey, one of the 10 physicians (10%) was "neutral" with the quality of the recordings using Google Glass, 6 physicians (60%) were "somewhat satisfied," and 3 physicians (30%) were "very satisfied." This small pilot study suggests that the quality of coronary angiogram video recordings obtained using Google Glass may be adequate for recognition of major findings, supporting its expanding use in telemedicine.

  1. Estimating Nielsen Numbers on Wedge Product Spaces

    Directory of Open Access Journals (Sweden)

    Kim Seung Won

    2007-01-01

    Full Text Available Let be a self-map of a finite polyhedron that is an aspherical wedge product space . In this paper, we estimate the Nielsen number of . In particular, we study some algebraic properties of the free products and then estimate Nielsen numbers on torus wedge surface with boundary, Klein bottle wedge surface with boundary, and torus wedge torus.

  2. Smartphone as a Remote Touchpad to Facilitate Visualization of 3D Cerebral Angiograms during Aneurysm Surgery.

    Science.gov (United States)

    Eftekhar, Behzad

    2017-09-01

    Background During aneurysm surgery, neurosurgeons may need to look at the cerebral angiograms again to better orient themselves to the aneurysm and also the surrounding vascular anatomy. Simplification of the intraoperative imaging review and reduction of the time interval between the view under the microscope and the angiogram review can theoretically improve orientation. Objective To describe the use of a smartphone as a remote touchpad to simplify intraoperative visualization of three-dimensional (3D) cerebral angiograms and reduce the time interval between the view under the microscope and the angiogram review. Methods Anonymized 3D angiograms of the patients in Virtual Reality Modelling Language format are securely uploaded to sketchfab.com, accessible through smartphone Web browsers. A simple software has been developed and made available to facilitate the workflow. The smartphone is connected wirelessly to an external monitor using a Chromecast device and is used intraoperatively as a remote touchpad to view/rotate/zoom the 3D aneurysms angiograms on the external monitor. Results Implementation of the method is practical and helpful for the surgeon in certain cases. It also helps the operating staff, registrars, and students to orient themselves to the surgical anatomy. I present 10 of the uploaded angiograms published online. Conclusion The concept and method of using the smartphone as a remote touchpad to improve intraoperative visualization of 3D cerebral angiograms is described. The implementation is practical, using easily available hardware and software, in most neurosurgical centers worldwide. The method and concept have potential for further development. Georg Thieme Verlag KG Stuttgart · New York.

  3. Complex Partial Epilepsy Associated with Temporal Lobe Developmental Venous Anomaly.

    Science.gov (United States)

    Sohail, Amna; Xiong, Zhengming; Qureshi, Mushtaq H; Qureshi, Adnan I

    2015-05-01

    Developmental venous anomalies (DVA) are found incidentally but sometimes patients with these anomalies present with varying degrees of neurologic manifestations. We report a patient with early onset complex partial epilepsy and associated DVA and discuss the natural history, neuroimaging and clinical characteristics, and management. A 21-year-old man presented with a history of complex partial epilepsy with secondary generalization which started at the age of 4 years. An electroencephalogram (EEG) was performed which demonstrated spike and wave discharges predominantly in the left frontotemporal region. A magnetic resonance imaging (MRI) was performed which demonstrated a linear flow void suggestive of a DVA. The angiogram demonstrated DVA that connected with the left transverse venous sinus and an anastomotic vein between the straight sinus and the transverse venous sinus traversing the brain parenchyma. He was started on carbamezipine for the treatment of complex partial seizures. Temporal lobe DVA may be associated with complex partial seizures and can be diagnosed by MRI and angiographic findings.

  4. Portal dosimetry in wedged beams

    NARCIS (Netherlands)

    Spreeuw, H.; Rozendaal, R.; Camargo, P.; Mans, A.; Wendling, M.; Olaciregui-Ruiz, I.; Sonke, J.J.; Herk, M. van; Mijnheer, B.

    2015-01-01

    Portal dosimetry using electronic portal imaging devices (EPIDs) is often applied to verify high-energy photon beam treatments. Due to the change in photon energy spectrum, the resulting dose values are, however, not very accurate in the case of wedged beams if the pixel-to-dose conversion for the

  5. Wedge-shaped parenchymal enhancement peripheral to the hepatic hemangioma : two-phase spiral CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyoung Won; Kim, Tae Kyoung; Han, Joon Koo [College of Medicine and The Institute of Radiation Medicine, Seoul National University, Seoul (Korea, Republic of); Kim, Ah Young; Lee, Hyun Ju [Asan Medical Center, University of Ulsan , Asan (Korea, Republic of); Song, Chi Sung; Choi, Byung Ihn [Seoul City Boramae Hospital, Seoul (Korea, Republic of)

    2000-02-01

    To determine the incidence of hepatic hemangiomas associated with wedge-shaped parenchymal enhancements adjacent to the tumors as seen on two-phase spiral CT images obtained during the hepatic arterial phase and to characterize the two-phase spiral CT findings of those hemangiomas. One hundred and eight consecutive hepatic hemangiomas in 63 patients who underwent two-phase spiral CT scanning during an 11-month period were included in this study. Two-phase spiral CT scans were obtained during the hepatic arterial phase (30-second delay) and portal venous phase (65-second delay) after injection of 120 mL of contrast material at a rate of 3 mL/sec. We evaluated the frequency with which wedge-shaped parenchymal enhancement was adjacent to the hemangiomas during the hepatic arterial phase and divided hemangiomas into two groups according to whether or not wedge-shaped parenchymal enhancement was noted (Group A and Group B). The presence of such enhancement in hemangiomas was correlated with tumor size and the grade of intratumoral enhancement. In 24 of 108 hemangiomas, wedge-shaped parenchymal enhancement adjacent to hepatic tumors was seen on two-phase CT images obtained during the hepatic arterial phase. Mean hemangioma size was 22mm in group A and 24mm in group B. There was no statistically significant relationship between lesion size and the presence of wedge-shaped parenchymal enhancement adjacent to a hemangioma. In 91.7% and 100% of tumors in Group A, and in 9.6% and 17.8% in Group B, hemangiomas showed more than 50% intratumoral enhancement during the arterial and portal venous phase, respectively. Wedge-shaped parenchymal enhancements peripheral to hepatic hemangiomas was more frequently found in tumors showing more than 50% intratumoral enhancement during these two phases (p less than 0.01). Wedge-shaped parenchymal enhancements is not uncommonly seen adjacent to hepatic hemangiomas on two-phase spiral CT images obtained during the hepatic arterial phase. A

  6. Erosion controls transpressional wedge kinematics

    Science.gov (United States)

    Leever, K. A.; Oncken, O.

    2012-04-01

    High resolution digital image analysis of analogue tectonic models reveals that erosion strongly influences the kinematics of brittle transpressional wedges. In the basally-driven experimental setup with low-angle transpression (convergence angle of 20 degrees) and a homogeneous brittle rheology, a doubly vergent wedge develops above the linear basal velocity discontinuity. In the erosive case, the experiment is interrupted and the wedge topography fully removed at displacement increments of ~3/4 the model thickness. The experiments are observed by a stereo pair of high resolution CCD cameras and the incremental displacement field calculated by Digital Particle Image Velocimetry (DPIV). From this dataset, fault slip on individual fault segments - magnitude and angle on the horizontal plane relative to the fault trace - is extracted using the method of Leever et al. (2011). In the non-erosive case, after an initial stage of strain localization, the wedge experiences two transient stages of (1) oblique slip and (2) localized strain partitioning. In the second stage, the fault slip angle on the pro-shear(s) rotates by some 30 degrees from oblique to near-orthogonal. Kinematic steady state is attained in the third stage when a through-going central strike-slip zone develops above the basal velocity discontinuity. In this stage, strain is localized on two main faults (or fault zones) and fully partitioned between plate boundary-parallel displacement on the central strike-slip zone and near-orthogonal reverse faulting at the front (pro-side) of the wedge. The fault slip angle on newly formed pro-shears in this stage is stable at 60-65 degrees (see also Leever et al., 2011). In contrast, in the erosive case, slip remains more oblique on the pro-shears throughout the experiment and a separate central strike-slip zone does not form, i.e. strain partitioning does not fully develop. In addition, more faults are active simultaneously. Definition of stages is based on slip on

  7. Coronary artery segmentation in X-ray angiogram using Gabor filters and differential evolution

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes S, F.; Hernandez A, A.; Cruz A, I. [Centro de Investigacion en Matematicas, A. C., Jalisco s/n, Col. Valenciana, 36240 Guanajuato, Gto. (Mexico); Solorio M, S. [IMSS, Unidad de Investigacion, UMAE Hospital de Especialidades No. 1 del Centro Medico Nacional del Bajio, 37260 Leon, Guanajuato (Mexico); Cordova F, T. [Universidad de Guanajuato, Departamento de Ingenieria Fisica, 37150 Leon, Guanajuato (Mexico); Avina C, J. G., E-mail: ivan.cruz@cimat.mx [Universidad de Guanajuato, Departamento de Electronica, 36885 Salamanca, Guanajuato (Mexico)

    2016-10-15

    Segmentation of coronary arteries in X-ray angiograms represents an essential task for computer-aided diagnosis, since it can help cardiologists in diagnosing and monitoring vascular abnormalities. Due to the main disadvantages of the X-ray angiograms are the nonuniform illumination, and the weak contrast between blood vessels and image background, different vessel enhancement methods have been introduced. In this paper, a novel method for blood vessel enhancement based on Gabor filters tuned using the optimization strategy of Differential evolution (De) is proposed. Because the Gabor filters are governed by three different parameters, the optimal selection of those parameters is highly desirable in order to maximize the vessel detection rate while reducing the computational cost of the training stage. To obtain the optimal set of parameters for the Gabor filters, the area (Az) under the receiver operating characteristic curve is used as objective function. In the experimental results, the proposed method obtained the highest detection performance with Az = 0.956 using a test set of 60 angiograms, and Az = 0.934 with a training set of 20 angiograms compared with different state-of-the-art vessel detection methods. In addition, the experimental results in terms of computational time have also shown that the proposed method can be highly suitable for clinical decision support. (Author)

  8. Ultrasonic friction power during Al wire wedge-wedge bonding

    Science.gov (United States)

    Shah, A.; Gaul, H.; Schneider-Ramelow, M.; Reichl, H.; Mayer, M.; Zhou, Y.

    2009-07-01

    Al wire bonding, also called ultrasonic wedge-wedge bonding, is a microwelding process used extensively in the microelectronics industry for interconnections to integrated circuits. The bonding wire used is a 25μm diameter AlSi1 wire. A friction power model is used to derive the ultrasonic friction power during Al wire bonding. Auxiliary measurements include the current delivered to the ultrasonic transducer, the vibration amplitude of the bonding tool tip in free air, and the ultrasonic force acting on the bonding pad during the bond process. The ultrasonic force measurement is like a signature of the bond as it allows for a detailed insight into mechanisms during various phases of the process. It is measured using piezoresistive force microsensors integrated close to the Al bonding pad (Al-Al process) on a custom made test chip. A clear break-off in the force signal is observed, which is followed by a relatively constant force for a short duration. A large second harmonic content is observed, describing a nonsymmetric deviation of the signal wave form from the sinusoidal shape. This deviation might be due to the reduced geometrical symmetry of the wedge tool. For bonds made with typical process parameters, several characteristic values used in the friction power model are determined. The ultrasonic compliance of the bonding system is 2.66μm/N. A typical maximum value of the relative interfacial amplitude of ultrasonic friction is at least 222nm. The maximum interfacial friction power is at least 11.5mW, which is only about 4.8% of the total electrical power delivered to the ultrasonic generator.

  9. Thrombosis of portal venous system after laparoscopic cholecystectomy in a patient with prothrombin gene mutation.

    Science.gov (United States)

    Gul, Waheed; Abbass, Khurram; Qazi, Arif M; Markert, Ronald J; Barde, Christopher J

    2012-01-01

    Laparoscopic cholecystectomy is now the gold standard for the treatment of symptomatic cholelithiasis. Portal venous thrombosis after laparoscopic cholecystectomy is rare. We report a case of thrombosis of the portal venous system after laparoscopic cholecystectomy in a patient with a latent prothrombin gene mutation. An abdominal computed tomography and magnetic resonance angiogram of the abdomen revealed portal, superior mesenteric, and splenic vein thrombosis. Testing for coagulation disorders showed a heterozygous form of factor II (prothrombin) G20210A mutation. Because of its rarity, information regarding this complication is limited.

  10. Anesthetic implications of total anomalous systemic venous connection to left atrium with left isomerism

    Directory of Open Access Journals (Sweden)

    Parimala Prasanna Simha

    2012-01-01

    Full Text Available Total anomalous systemic venous connection (TASVC to the left atrium (LA is a rare congenital anomaly. An 11-year-old girl presented with complaints of palpitations and cyanosis. TASVC with left isomerism and noncompaction of LV was diagnosed after contrast echocardiogram and computed tomography angiogram. The knowledge of anatomy and pathophysiology is essential for the successful management of these cases. Anesthetic concerns in this case were polycythemia, paradoxical embolism and rhythm abnormalities. The patient was successfully operated by rerouting the systemic venous connection to the right atrium.

  11. Geometry and kinematics of extensional structural wedges

    Science.gov (United States)

    Gui, Baoling; He, Dengfa; Zhang, Yongsheng; Sun, Yanpeng; Huang, Jingyi; Zhang, Wenjun

    2017-03-01

    Structural wedges in the compressive environment have been recognized and studied in different locations. However, extension structural wedges are less well-understood. Based on the normal fault-bend folding theory and inclined shear model, this paper quantitatively analyses deformations related to extensional structural wedges and builds a series of geometric models for them. An extensional structural wedge is a fault-block held by two or more normal faults, the action of which would fold its overlying strata. Extensional structural wedges of different shapes will lead to different deformation results for the overlying strata, and this paper illustrates both the triangular and quadrangular wedges and their related deformations. This paper also discusses differences between the extensional structural wedges and the normal fault-bend-folding. By analysing two seismic sections from Langfang-Gu'an Sag, East China, this paper provides two natural examples of the triangular and quadrangular extensional structural wedges, where the models can reasonably explain the overlying distinct highs and lows without obvious faults. The establishment of a geometric model of extensional structural wedges can provide reference and theoretical bases for future quantitative analysis of deformations in the extensional environment.

  12. Ice Particle Impacts on a Moving Wedge

    Science.gov (United States)

    Vargas, Mario; Struk, Peter M.; Kreeger, Richard E.; Palacios, Jose; Iyer, Kaushik A.; Gold, Robert E.

    2014-01-01

    This work presents the results of an experimental study of ice particle impacts on a moving wedge. The experiment was conducted in the Adverse Environment Rotor Test Stand (AERTS) facility located at Penn State University. The wedge was placed at the tip of a rotating blade. Ice particles shot from a pressure gun intercepted the moving wedge and impacted it at a location along its circular path. The upward velocity of the ice particles varied from 7 to 12 meters per second. Wedge velocities were varied from 0 to 120 meters per second. Wedge angles tested were 0 deg, 30 deg, 45 deg, and 60 deg. High speed imaging combined with backlighting captured the impact allowing observation of the effect of velocity and wedge angle on the impact and the post-impact fragment behavior. It was found that the pressure gun and the rotating wedge could be synchronized to consistently obtain ice particle impacts on the target wedge. It was observed that the number of fragments increase with the normal component of the impact velocity. Particle fragments ejected immediately after impact showed velocities higher than the impact velocity. The results followed the major qualitative features observed by other researchers for hailstone impacts, even though the reduced scale size of the particles used in the present experiment as compared to hailstones was 4:1.

  13. Follow-up CT pulmonary angiograms in patients with acute pulmonary embolism.

    Science.gov (United States)

    Stein, Paul D; Matta, Fadi; Hughes, Patrick G; Hourmouzis, Zak N; Hourmouzis, Nina P; Schweiss, Robert E; Bach, Jennifer A; Kazan, Viviane M; Kakish, Edward J; Keyes, Daniel C; Hughes, Mary J

    2016-10-01

    Computed tomographic (CT) angiography is associated with a non-negligible lifetime attributable risk of cancer. The risk is considerably greater for women and younger patients. Recognizing that there are risks from radiation, the purpose of this investigation was to assess the frequency of follow-up CT angiograms in patients with acute pulmonary embolism. This was a retrospective cohort study of patients aged ≥18 years with acute pulmonary embolism seen in three emergency departments from January 2013 to December 2014. Records of all patients were reviewed for at least 14 months. Pulmonary embolism was diagnosed by CT angiography in 600 patients. At least one follow-up CT angiogram in 1 year was obtained in 141 of 600 (23.5 %). Two follow-ups in 1 year were obtained in 40 patients (6.7 %), 3 follow-ups were obtained in 15 patients (2.5 %), and 4 follow-ups were obtained in 3 patients (0.5 %). Among young women (aged ≤29 years) with pulmonary embolism, 10 of 21 (47.6 %) had at least 1 follow-up and 4 of 21 (19.0 %) had 2 or more follow-ups in 1 year. Among all patients, recurrent pulmonary embolism was diagnosed in 15 of 141 (10.6 %) on the first follow-up CT angiogram and in 6 of 40 (15.0 %) on the second follow-up. Follow-up CT angiograms were obtained in a significant proportion of patients with pulmonary embolism, including young women, the group with the highest risk. Alternative options might be considered to reduce the hazard of radiation-induced cancer, particularly in young women.

  14. CT pulmonary angiogram for assessing the treatment outcome of acute pulmonary embolism.

    Science.gov (United States)

    Zhou, Hai-Ting; Yan, Wen-Ying; Zhao, De-Li; Liang, Hong-Wei; Wang, Guo-Kun; Ling, Zai-Sheng; Zhang, Jin-Ling

    2017-12-11

    To discuss the value of CT pulmonary angiogram (CTPA) for assessing the treatment outcome of acute pulmonary embolism (APE). CT pulmonary angiogram data and other clinical data were collected for 28 cases diagnosed as APE and analyzed retrospectively. The number and positions of emboli in the pulmonary artery, pulmonary artery obstruction index, right ventricular/left ventricular diameter ratio, main pulmonary artery/ascending aorta diameter ratio and blood oxygen saturation, and pulmonary arterial pressure were compared before and after treatment. Of 28 cases, emboli in the pulmonary artery completely or partially disappeared in 16 and 12 cases, respectively. CPTA indicated that the pulmonary arterial pressure decreased dramatically and the blood oxygen saturation increased after treatment in 26 cases. There were significant differences in the number and positions of pulmonary emboli and in pulmonary artery obstruction index before and after treatment in 28 cases (P  .05). CT pulmonary angiogram proved reliable for assessing the treatment efficacy of APE, providing more clinical information on the patients' status. © 2017, Wiley Periodicals, Inc.

  15. Central venous catheter - flushing

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000157.htm Central venous catheter - flushing To use the sharing features on this page, please enable JavaScript. You have a central venous catheter. This is a tube that goes into a ...

  16. Peripheral Angiogram

    Science.gov (United States)

    ... State SELECT YOUR LANGUAGE Español (Spanish) 简体中文 (Traditional Chinese) 繁体中文 (Simplified Chinese) Tiếng Việt (Vietnamese) Healthy Living for Heart.org ... and Live Our Interactive Cardiovascular Library has detailed animations and illustrations to help you learn about conditions, ...

  17. Use of Wedge Absorbers in MICE

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, D. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Summers, D. [Univ. of Mississippi, Oxford, MS (United States); Mohayai, T. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); IIT, Chicago, IL (United States); Snopok, P. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); IIT, Chicago, IL (United States); Rogers, C. [Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab. (RAL)

    2017-03-01

    Wedge absorbers are needed to obtain longitudinal cooling in ionization cooling. They also can be used to obtain emittance exchanges between longitudinal and transverse phase space. There can be large exchanges in emittance, even with single wedges. In the present note we explore the use of wedge absorbers in the MICE experiment to obtain transverse–longitudinal emittance exchanges within present and future operational conditions. The same wedge can be used to explore “direct” and “reverse” emittance exchange dynamics, where direct indicates a configuration that reduces momentum spread and reverse is a configuration that increases momentum spread. Analytical estimated and ICOOL and G4BeamLine simulations of the exchanges at MICE parameters are presented. Large exchanges can be obtained in both reverse and direct configurations.

  18. Semi-infinite wedges and vertex operators

    CERN Document Server

    Stern, E

    1995-01-01

    The level 1 highest weight modules of the quantum affine algebra U_q(\\widehat{\\frak{sl}}_n) can be described as spaces of certain semi-infinite wedges. Using a q-antisymmetrization procedure, these semi-infinite wedges can be realized inside an infinite tensor product of evaluation modules. This realization gives rise to simple descriptions of vertex operators and (up to a scalar function) their compositions.

  19. A Wedge Absorber Experiment at MICE

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, David [Fermilab; Mohayai, Tanaz [IIT, Chicago; Rogers, Chris [Rutherford; Snopok, Pavel [IIT, Chicago; Summers, Don [Mississippi U.

    2017-05-01

    Emittance exchange mediated by wedge absorbers is required for longitudinal ionization cooling and for final transverse emittance minimization for a muon collider. A wedge absorber within the MICE beam line could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders, as well as configurations for low-energy muon sources. Parameters for this test are explored in simulation and possible experimental configurations with simulated results are presented.

  20. Stability analysis for three-plane wedges

    Science.gov (United States)

    Tharp, Thomas M.

    Stability analysis for rock wedges bounded by three planar discontinuities is a time-consuming procedure usually carried out by stereographic projection. An algorithm is presented which identifies the behavior mode for wedges and calculates the factor of safety more accurately than is possible by graphical methods. The upper and lower hemisphere stereographic projections also are plotted. This is the standard presentation format and it allows a visual check of the influence of assumed geometries and friction angles.

  1. Aerodynamic Analysis Over Double Wedge Airfoil

    Science.gov (United States)

    Prasad, U. S.; Ajay, V. S.; Rajat, R. H.; Samanyu, S.

    2017-05-01

    Aeronautical studies are being focused more towards supersonic flights and methods to attain a better and safer flight with highest possible performance. Aerodynamic analysis is part of the whole procedure, which includes focusing on airfoil shapes which will permit sustained flight of aircraft at these speeds. Airfoil shapes differ based on the applications, hence the airfoil shapes considered for supersonic speeds are different from the ones considered for Subsonic. The present work is based on the effects of change in physical parameter for the Double wedge airfoil. Mach number range taken is for transonic and supersonic. Physical parameters considered for the Double wedge case with wedge angle (ranging from 5 degree to 15 degree. Available Computational tools are utilized for analysis. Double wedge airfoil is analysed at different Angles of attack (AOA) based on the wedge angle. Analysis is carried out using fluent at standard conditions with specific heat ratio taken as 1.4. Manual calculations for oblique shock properties are calculated with the help of Microsoft excel. MATLAB is used to form a code for obtaining shock angle with Mach number and wedge angle at the given parameters. Results obtained from manual calculations and fluent analysis are cross checked.

  2. Turbulent wedge spreading dynamics and control strategies

    Science.gov (United States)

    Suryanarayanan, Saikishan; Goldstein, David; Brown, Garry

    2017-11-01

    Turbulent wedges are encountered in some routes to transition in wall bounded flows, particularly those involving surface roughness. They are characterized by strongly turbulent regions that are formed downstream of large disturbances, and spread into the non-turbulent flow. Altering the wedge spreading mechanism is a possible drag reduction strategy. Following recent studies of Goldstein, Chu and Brown (Flow Turbul. Combust. 98(1), 2017) and Kuester and White (Exp. Fluids 57(4), 2016), we explore the relation between the base flow vorticity field and turbulent wedge spreading using immersed boundary direct numerical simulations. The lateral spreading rate of the wedges are similar for high Reynolds number boundary layers and Couette flow, but differences emerge in wall normal propagation of turbulence. We also attempt to utilize the surface texture based strategy suggested by Strand and Goldstein (J. Fluid Mech. 668, 2011) to reduce the spreading of isolated turbulent spots, for turbulent wedge control. The effects of height, spacing and orientation of fins on the dynamics of wedge evolution are studied. The results are interpreted from a vorticity dynamics point of view. Supported by AFOSR # FA9550-15-1-0345.

  3. A Case of Cardiac Cephalalgia Showing Reversible Coronary Vasospasm on Coronary Angiogram

    Science.gov (United States)

    Yang, YoungSoon; Jin, Dong Gyu; Jang, Il Mi; Jang, YoungHee; Na, Hae Ri; Kim, SanYun

    2010-01-01

    Background Under certain conditions, exertional headaches may reflect coronary ischemia. Case Report A 44-year-old woman developed intermittent exercise-induced headaches with chest tightness over a period of 10 months. Cardiac catheterization followed by acetylcholine provocation demonstrated a right coronary artery spasm with chest tightness, headache, and ischemic effect of continuous electrocardiography changes. The patient's headache disappeared following intra-arterial nitroglycerine injection. Conclusions A coronary angiogram with provocation study revealed variant angina and cardiac cephalalgia, as per the International Classification of Headache Disorders (code 10.6). We report herein a patient with cardiac cephalalgia that manifested as reversible coronary vasospasm following an acetylcholine provocation test. PMID:20607049

  4. Studying wedge factors and beam profiles for physical and enhanced dynamic wedges

    Directory of Open Access Journals (Sweden)

    Ahmad Misbah

    2010-01-01

    Full Text Available This study was designed to investigate variation in Varian′s Physical and Enhanced Dynamic Wedge Factors (WF as a function of depth and field size. The profiles for physical wedges (PWs and enhanced dynamic wedges (EDWs were also measured using LDA-99 array and compared for confirmation of EDW angles at different depths and field sizes. WF measurements were performed in water phantom using cylindrical 0.66 cc ionization chamber. WF was measured by taking the ratio of wedge and open field ionization data. A normalized wedge factor (NWF was introduced to circumvent large differences between wedge factors for different wedge angles. A strong linear dependence of PW Factor (PWF with depth was observed. Maximum variation of 8.9% and 4.1% was observed for 60° PW with depth at 6 and 15 MV beams respectively. The variation in EDW Factor (EDWF with depth was almost negligible and less than two per cent. The highest variation in PWF as a function of field size was 4.1% and 3.4% for thicker wedge (60° at 6 and 15 MV beams respectively and decreases with decreasing wedge angle. EDWF shows strong field size dependence and significant variation was observed for all wedges at both photon energies. Differences in profiles between PW and EDW were observed on toe and heel sides. These differences were dominant for larger fields, shallow depths, thicker wedges and low energy beam. The study indicated that ignoring depth and field size dependence of WF may result in under/over dose to the patient especially doing manual point dose calculation.

  5. Mantle wedge serpentinization effects on slab dips

    Directory of Open Access Journals (Sweden)

    Eh Tan

    2017-01-01

    Full Text Available The mechanical coupling between a subducting slab and the overlying mantle wedge is an important factor in controlling the subduction dip angle and the flow in mantel wedge. This paper investigates the role of the amount of mantle serpentinization on the subduction zone evolution. With numerical thermos-mechanical models with elasto-visco-plastic rheology, we vary the thickness and depth extent of mantle serpentinization in the mantle wedge to control the degree of coupling between the slab and mantle wedge. A thin serpentinized mantle layer is required for stable subduction. For models with stable subduction, we find that the slab dip is affected by the down-dip extent and the mantle serpentinization thickness. A critical down-dip extent exists in mantle serpentinization, determined by the thickness of the overriding lithosphere. If the down-dip extent does not exceed the critical depth, the slab is partially coupled to the overriding lithosphere and has a constant dip angle regardless of the mantle serpentinization thickness. However, if the down-dip extent exceeds the critical depth, the slab and the base of the overriding lithosphere would be separated and decoupled by a thick layer of serpentinized peridotite. This allows further slab bending and results in steeper slab dip. Increasing mantle serpentinization thickness will also result in larger slab dip. We also find that with weak mantle wedge, there is no material flowing from the asthenosphere into the serpentinized mantle wedge. All of these results indicate that serpentinization is an important ingredient when studying the subduction dynamics in the mantle wedge.

  6. Vertebral wedging characteristic changes in scoliotic spines.

    Science.gov (United States)

    Parent, Stefan; Labelle, Hubert; Skalli, Wafa; de Guise, Jacques

    2004-10-15

    A morphometric analysis of vertebral wedging in vertebrae from scoliotic specimens. To quantify the vertebral body changes in 30 anatomic specimens affected by a scoliotic deformity. Only a few studies have evaluated the exact changes occurring at the level of the vertebral body in scoliotic spines. Most are observational studies of rare scoliotic specimens presenting major curvatures. The orientation of vertebral wedging is important for the planning of corrective surgery, performing vertebral osteotomy, and the evaluation of possible growth modulation. Thirty scoliotic specimens with curves presenting various degrees of severity were studied using a three-dimensional digitizing protocol developed to create a precise three-dimensional reconstruction of the vertebrae. Every scoliotic specimen was then matched with a normal specimen, and comparisons were made on the vertebral body parameters both for thoracic and lumbar vertebrae. Analysis of variance and t test calculations were performed to identify significant differences with P = 0.05. A total of 471 vertebrae from scoliotic spines and 510 vertebrae from normal specimens were measured. Vertebral wedging increased progressively towards the apex of the curve and was maximal at the apex. Vertebral wedging was more prominent in the frontal plane, and there was minimal wedging in the sagittal plane. Vertebral heights were significantly different at T3 and T4 for the upper adjacent curve and at T6-T8 for a typical right thoracic curve, with smaller heights located on the concavity of the curve. No changes were observed on the convexity of the curve. Vertebral wedging is an essential component of the scoliotic deformity. The present study provides critical information for corrective surgery and vertebral osteotomy, as vertebral wedging occurs primarily in the frontal plane. Accurate knowledge of this deformity should also provide new insight into corrective surgical strategies aiming at growth modulation and more

  7. Optical dating of relict sand wedges and composite-wedge pseudomorphs in Flanders, Belgium

    DEFF Research Database (Denmark)

    Buylaert, Jan-Pieter; Ghysels, Günther; Murray, Andrew S.

    2009-01-01

    We report on quartz Optically Stimulated Luminescence (OSL) dating of the infill of 14 relict sand wedges and composite-wedge pseudomorphs at 5 different sites in Flanders, Belgium. A laboratory dose recovery test indicates that the single-aliquot regenerative-dose (SAR) procedure is suitable...

  8. Evaluation of angiograms obtained from a laser-based x-ray source in DESA regime

    Science.gov (United States)

    Scalzetti, Ernest M.; Krol, Andrzej; Gagne, George M.; Renvyle, Ted T.; Chamberlain, Charles C.; Kieffer, Jean-Claude; Jiang, Zhiming; Yu, Jianfan

    1999-05-01

    Contrast resolution of angiograms created using a laser-based x-ray source in Dual Energy Subtraction Angiography (DESA) regime has been investigated. It has been compared to contrast in angiograms obtained using an x-ray tube-based clinical angiography unit in DSA mode. Contrast detail phantoms and rats with opacified vascular structures were imaged. A table top terawatt laser was used (1019 Wcm-2, 150 fs or 450 fs per pulse). For Iodine contrast agent, an Iodine filter was used with the BaF2 target to obtain images with mean x-rays energy below the Iodine K-edge. La target and La filter was used to obtain images with mean x-rays energy above the Iodine K-edge. For Ba contrast agent, a Nd filter was used with the Nd target to obtain images with mean x-rays energy below the Ba K-edge. Gd target and Nd filter was used to obtain images with mean x-rays energy above the Barium K-edge. It has been determined that the laser-based DESA with properly selected targets demonstrates better contrast than a standard x-ray tube-based DSA angiography. We conclude that laser-based x-ray source has promise for angiography in DESA regime providing that sufficient x-ray flux can be delivered by the laser.

  9. Segmentation of Coronary Angiograms Using Gabor Filters and Boltzmann Univariate Marginal Distribution Algorithm

    Directory of Open Access Journals (Sweden)

    Fernando Cervantes-Sanchez

    2016-01-01

    Full Text Available This paper presents a novel method for improving the training step of the single-scale Gabor filters by using the Boltzmann univariate marginal distribution algorithm (BUMDA in X-ray angiograms. Since the single-scale Gabor filters (SSG are governed by three parameters, the optimal selection of the SSG parameters is highly desirable in order to maximize the detection performance of coronary arteries while reducing the computational time. To obtain the best set of parameters for the SSG, the area (Az under the receiver operating characteristic curve is used as fitness function. Moreover, to classify vessel and nonvessel pixels from the Gabor filter response, the interclass variance thresholding method has been adopted. The experimental results using the proposed method obtained the highest detection rate with Az=0.9502 over a training set of 40 images and Az=0.9583 with a test set of 40 images. In addition, the experimental results of vessel segmentation provided an accuracy of 0.944 with the test set of angiograms.

  10. Adaptive Ridge Point Refinement for Seeds Detection in X-Ray Coronary Angiogram

    Directory of Open Access Journals (Sweden)

    Ruoxiu Xiao

    2015-01-01

    Full Text Available Seed point is prerequired condition for tracking based method for extracting centerline or vascular structures from the angiogram. In this paper, a novel seed point detection method for coronary artery segmentation is proposed. Vessels on the image are first enhanced according to the distribution of Hessian eigenvalue in multiscale space; consequently, centerlines of tubular vessels are also enhanced. Ridge point is extracted as candidate seed point, which is then refined according to its mathematical definition. The theoretical feasibility of this method is also proven. Finally, all the detected ridge points are checked using a self-adaptive threshold to improve the robustness of results. Clinical angiograms are used to evaluate the performance of the proposed algorithm, and the results show that the proposed algorithm can detect a large set of true seed points located on most branches of vessels. Compared with traditional seed point detection algorithms, the proposed method can detect a larger number of seed points with higher precision. Considering that the proposed method can achieve accurate seed detection without any human interaction, it can be utilized for several clinical applications, such as vessel segmentation, centerline extraction, and topological identification.

  11. Recrudescence of Symptoms of Remote Ischemic Stroke After a Cerebral Angiogram.

    Science.gov (United States)

    Falatko, Stephanie R; Schmalz, Philip G R; Harrigan, Mark

    2017-05-01

    Ischemic stroke recrudescence, or reappearance of previously resolved symptoms of ischemic stroke, may occur after physiologic stress. Although generally thought to be uncommon, this syndrome may account for a significant proportion of stroke mimics. A 67-year-old man was admitted with a Hunt and Hess grade 2 spontaneous subarachnoid hemorrhage. He underwent digital subtraction cerebral angiography as part of imaging evaluation. About 30 minutes after the procedure, he developed dysarthria, right facial droop, and right pronator drift. The patient and family denied a history of similar symptoms or previous ischemic stroke. Brain magnetic resonance imaging demonstrated a remote left lacunar infarction. The symptoms resolved after 24 hours and were attributed to recrudescence of the patient's previous lacunar infarction. The physiological stress of the subarachnoid hemorrhage combined with the cerebral angiogram likely triggered the event. Recrudescence of symptoms of a previous stroke may be initiated by subarachnoid hemorrhage and/or a cerebral angiogram. The possibility of ischemic stroke recrudescence should be kept in mind as a possible stroke mimic. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Cerebral venous angiomas

    Energy Technology Data Exchange (ETDEWEB)

    Agnoli, A.L.; Hildebrandt, G.

    1985-01-01

    Clinical symptoms and radiological signs in 15 patients with cerebral venous malformations are presented and the diagnostic problems discussed. The circulation time in combination with cerebral malformations and angiomas of the scalp are described. CT findings in cases of venous malformations of the brain stem are evaluated. Spot-like enhancement, as well as sharply demarcated round shaped enhancement are characteristic for venous angiomas. Cavernous angiomas usually present as homogenous or inhomogenous round shaped enhanced areas. (Author).

  13. Persistent portal venous gas.

    Science.gov (United States)

    Huurman, Volkert A L; Visser, Leo G; Steens, Stefan C A; Terpstra, Onno T; Schaapherder, Alexander F M

    2006-05-01

    This case report describes a patient diagnosed with ongoing portal venous gas, initiated by a rather common Campylobacter enterocolitis and maintained by septic thrombophlebitis and possibly by chronic cholecystitis. Cholecystectomy attenuated the patient's septic condition. The etiology of portal venous gas determines both the patient's prognosis and the choice for either conservative or surgical treatment. This report describes persistence of portal venous gas for a long period and a possible role for chronic cholecystitis as a cause.

  14. Commissioning, clinical implementation and quality assurance of Siemen's Virtual Wedge.

    Science.gov (United States)

    Rathee, S; Kwok, C B; MacGillivray, C; Mirzaei, M

    1999-01-01

    This report presents the results of commissioning, clinical implementation and quality assurance of Siemens Virtual Wedge. Our measurements show that: (1) wedge factors are within 2% of unity, (2) percentage depth doses are within 1% of open beam data, and (3) wedged beam profiles can be modeled similarly to a physical wedge and follow a well defined equation to facilitate modeling of an arbitrary wedge angle. The gantry angle dependence of wedge profiles is similar to open beam profiles. The output of wedged fields is linear with delivered monitor units within 1%. Quality assurance results indicate the wedge profiles are very stable over time. Day to day variations of two points measured along the wedge gradient direction are within 1.5%.

  15. FLAIR vascular hyperintensities and dynamic 4D angiograms for the estimation of collateral blood flow in posterior circulation occlusion

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, Alex; Wenz, Holger; Kerl, Hans Ulrich; Al-Zghloul, Mansour; Habich, Sonia; Groden, Christoph [University of Heidelberg, Department of Neuroradiology, Universitaetsmedizin Mannheim, Mannheim (Germany)

    2014-09-15

    The objectives of this paper are to assess collateral blood flow in posterior circulation occlusion by MRI-based approaches (fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVHs), collateralization on dynamic 4D angiograms) and investigate its relation to ischemic lesion size and growth. In 28 patients with posterior cerebral artery (PCA) and 10 patients with basilar artery (BA) occlusion, MRI findings were analyzed, with emphasis on distal FVH and collateralization on dynamic 4D angiograms. In PCA occlusion, distal FVH was observed in 18/29 (62.1 %), in BA occlusion, in 8/10 (80 %) cases. Collateralization on dynamic 4D angiograms was graded 1 in 8 (27.6 %) patients, 2 in 1 (3.4 %) patient, 3 in 12 (41.4 %) patients, and 4 in 8 (27.6 %) patients with PCA occlusion and 0 in 1 (10 %) patient, 2 in 3 (30 %) patients, 3 in 1 (10 %) patient, and 4 in 5 (50 %) patients with BA occlusion. FVH grade showed neither correlation with initial or follow-up diffusion-weighted image (DWI) lesion size nor DWI-perfusion-weighted imaging (PWI) mismatch ratio. Collateralization on dynamic 4D angiograms correlated inversely with initial DWI lesion size and moderately with the DWI-(PWI) mismatch ratio. The combination of distal FVH and collateralization grade on dynamic 4D angiograms correlated inversely with initial as well as follow-up DWI lesion size and highly with the DWI-PWI mismatch ratio. In posterior circulation occlusion, FVH is a frequent finding, but its prognostic value is limited. Dynamic 4D angiograms are advantageous to examine and graduate collateral blood flow. The combination of both parameters results in an improved characterization of collateral blood flow and might have prognostic relevance. (orig.)

  16. Graphene Plasmons in Triangular Wedges and Grooves

    DEFF Research Database (Denmark)

    Gonçalves, P. A. D.; Dias, E. J. C.; Xiao, Sanshui

    2016-01-01

    and tunability of graphene plasmons guided along the apex of a graphene-covered dielectric wedge or groove. In particular, we present a quasi-analytic model to describe the plasmonic eigenmodes in such a system, including the complete determination of their spectrum and corresponding induced potential...... and electric-field distributions. We have found that the dispersion of wedge/groove graphene plasmons follows the same functional dependence as their flat-graphene plasmon counterparts, but now scaled by a (purely) geometric factor in which all the information about the system’s geometry is contained. We...

  17. Excessive Hepatic Arterial-portal Venous Shunting May Predict Failure of Microparticle Localization in Hepatocellular Carcinomas.

    Science.gov (United States)

    Tan, Andrew Eik Hock; Kao, Yung Hsiang; Xie, Wanying

    2013-01-01

    Locoregional treatment of hepatocellular carcinomas using yttrium-90 (Y-90) microspheres is an emerging modality, and involves the administration of such radioactive particles directly into the hepatic arterial vasculature. We present the case of a 58-year-old gentleman undergoing evaluation for Y-90 microsphere therapy for hepatocellular carcinoma, in which our findings suggest that significant hepatic arterial portal venous shunting detected during the angiogram maybe a predictor of poor localization of microspheres in the turmor, and that centers that utilize body surface area (BSA) approaches for dosimetry should take note of such findings.

  18. Deep venous thrombosis after office vasectomy: a case report

    Directory of Open Access Journals (Sweden)

    Zazove Philip

    2010-08-01

    Full Text Available Abstract Introduction Postoperative pulmonary embolism is considered a complication of major surgery. However, thromboembolism can also occur following minor procedures. We report a case of a major embolic event following a straightforward office vasectomy. Case presentation A healthy 35-year-old Asian man underwent an uncomplicated office vasectomy. Soon after, he noticed vague chest pain and dyspnea. Lower extremity Doppler ultrasound revealed acute venous thrombosis. A computer-assisted tomography angiogram revealed extensive bilateral pulmonary emboli. Extensive laboratory work-up failed to identify thrombophilia. He has not had any recurrences in the eight years since the initial presentation. Conclusion This case highlights that major embolic events can follow minor office procedures. Patients with suggestive findings should be investigated aggressively.

  19. Lifestyle and venous thrombosis

    NARCIS (Netherlands)

    Pomp, Elisabeth Rebekka

    2008-01-01

    In the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis (MEGA study), a large population-based case-control study, we investigated lifestyle factors as risk factors for venous thrombosis. Overweight, smoking and alcohol consumption were addressed and pregnancy and

  20. Assessing Intra-arterial Complications of Planning and Treatment Angiograms for Y-90 Radioembolization

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Osman, E-mail: osman1423@gmail.com [Rush University Medical Center, Section of Interventional Radiology, Department of Radiology (United States); Patel, Mikin V. [University of Chicago, Department of Radiology (United States); Masrani, Abdulrahman; Chong, Bradford; Osman, Mohammed; Tasse, Jordan; Soni, Jayesh; Turba, Ulku Cenk; Arslan, Bulent [Rush University Medical Center, Section of Interventional Radiology, Department of Radiology (United States)

    2017-05-15

    PurposeTo report hepatic arterial-related complications encountered during planning and treatment angiograms for radioembolization and understand any potential-associated risk factors.Materials and Methods518 mapping or treatment angiograms for 180 patients with primary or metastatic disease to the liver treated by Yttrium-90 radioembolization between 2/2010 and 12/2015 were retrospectively reviewed. Intra-procedural complications were recorded per SIR guidelines. Patient demographics, indication for treatment, prior exposure to chemotherapeutic agents, operator experience, and disease burden were reviewed. Technical variables including type of radioembolic (glass vs. resin microspheres), indication for angiography (mapping vs. treatment), variant anatomy, and attempts at coil embolization were also assessed.ResultsThirteen (13/518, 2.5%) arterial-related complications occurred in 13 patients. All but two complications resulted during transcatheter coil embolization to prevent non-target embolization. Complications included coil migration (n = 6), arterial dissection (n = 2), focal vessel perforation (n = 2), arterial thrombus (n = 2), and vasospasm prohibiting further arterial sub-selection (n = 1). Transarterial coiling was identified as a significant risk factor of complications on both univariate and multivariate regression analysis (odds ratio 7.8, P = 0.004). Usage of resin microspheres was also a significant risk factor (odds ratio 9.5, P = 0.042). No other technical parameters or pre-procedural variables were significant after adjusting for confounding on multivariate analysis (P > 0.05).ConclusionIntra-procedural hepatic arterial complications encountered during radioembolization were infrequent but occurred mainly during coil embolization to prevent non-target delivery to extra-hepatic arteries.

  1. Are Pericentric Inversions Reorganizing Wedge Shell Genomes?

    Directory of Open Access Journals (Sweden)

    Daniel García-Souto

    2017-12-01

    Full Text Available Wedge shells belonging to the Donacidae family are the dominant bivalves in exposed beaches in almost all areas of the world. Typically, two or more sympatric species of wedge shells differentially occupy intertidal, sublittoral, and offshore coastal waters in any given locality. A molecular cytogenetic analysis of two sympatric and closely related wedge shell species, Donax trunculus and Donax vittatus, was performed. Results showed that the karyotypes of these two species were both strikingly different and closely alike; whilst metacentric and submetacentric chromosome pairs were the main components of the karyotype of D. trunculus, 10–11 of the 19 chromosome pairs were telocentric in D. vittatus, most likely as a result of different pericentric inversions. GC-rich heterochromatic bands were present in both species. Furthermore, they showed coincidental 45S ribosomal RNA (rRNA, 5S rRNA and H3 histone gene clusters at conserved chromosomal locations, although D. trunculus had an additional 45S rDNA cluster. Intraspecific pericentric inversions were also detected in both D. trunculus and D. vittatus. The close genetic similarity of these two species together with the high degree of conservation of the 45S rRNA, 5S rRNA and H3 histone gene clusters, and GC-rich heterochromatic bands indicate that pericentric inversions contribute to the karyotype divergence in wedge shells.

  2. Diffraction of electromagnetic waves by a rectangular wedge structure

    Science.gov (United States)

    Makarov, G. I.; Sozonov, A. P.

    A theoretical problem of electromagnetic wave diffraction in a system of two rectangular wedges is examined: a perfectly conducting wedge and a wedge with finite relative permittivity, the two wedges having a common face. For the Fourier component of the diffraction field, a shifting Riemann boundary value problem is obtained. This problem is reduced to a convolution-type integral equation for the semiaxis, with the kernel taking the form of the sum of the difference and regular kernels.

  3. Diagnostic contribution of cardiac magnetic resonance in patients with acute coronary syndrome and culprit-free angiograms.

    Science.gov (United States)

    Kawecki, Damian; Morawiec, Beata; Monney, Pierre; Pellaton, Cyril; Wojciechowska, Celina; Jojko, Joanna; Basiak, Marcin; Przywara-Chowaniec, Brygida; Fournier, Stephane; Nowalany-Kozielska, Ewa; Schwitter, Juerg; Muller, Olivier

    2015-01-14

    In spite of robust knowledge about underlying ischemic myocardial damage, acute coronary syndromes (ACS) with culprit-free angiograms raise diagnostic concerns. The present study aimed to evaluate the additional value of cardiac magnetic resonance (CMR) over commonly available non-CMR standard tests, for the differentiation of myocardial injury in patients with ACS and non-obstructed coronary arteries. Patients with ACS, elevated hs-TnT, and a culprit-free angiogram were prospectively enrolled into the study between January 2009 and July 2013. After initial evaluation with standard tests (ECG, echocardiography, hs-TnT) and provisional exclusion of acute myocardial infarction (AMI) in coronary angiogram, patients were referred for CMR with the suspicion of myocarditis or Takotsubo cardiomyopathy (TTC). According to the result of CMR, patients were reclassified as having myocarditis, AMI, TTC, or non-injured myocardium as assessed by late gadolinium enhancement. Out of 5110 patients admitted with ACS, 75 had normal coronary angiograms and entered the study; 69 of them (92%) were suspected for myocarditis and 6 (8%) for TTC. After CMR, 49 patients were finally diagnosed with myocarditis (65%), 3 with TTC (4%), 7 with AMI (9%), and 16 (21%) with non-injured myocardium. The provisional diagnosis was changed or excluded in 23 patients (31%), with a 9% rate of unrecognized AMI. The study results suggest that the evaluation of patients with ACS and culprit-free angiogram should be complemented by a CMR examination, if available, because the initial work-up with non-CMR tests leads to a significant proportion of misdiagnosed AMI.

  4. [Developmental venous anomaly (DVA)].

    Science.gov (United States)

    Zimmer, A; Hagen, T; Ahlhelm, F; Viera, J; Reith, W; Schulte-Altedorneburg, G

    2007-10-01

    As congenital anatomic variants of venous drainage, developmental venous anomalies (DVA) represent up to 60% of all cerebral vascular malformations. The prior term "venous angioma" is a misnomer implicating an abnormal vascular structure with an increased bleeding risk. They are often found incidentally and are hardly ever symptomatic. Their morphologic characteristics are dilated vessels in the white matter, which converge on a greater collector vein, forming the typical caput medusae. They drain into the superficial or deep venous system. The frequent association with other, potentially bleeding-prone vascular malformations is clinically relevant, in particular cavernous angioma, which might require therapeutic action. Therefore, coincident vascular lesions need to be actively sought by appropriate additional imaging techniques.

  5. Venous thrombosis: an overview

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, C.W.

    1986-07-01

    Venous thromboembolic disease contributes to morbidity and mortality in certain groups of hospitalized patients, particularly those who have undergone surgery. Although principles of treatment have changed relatively little during the past 20 years, significant advances have been made in the diagnosis of deep vein thrombosis (DVT). Venography, once the only reliable diagnostic technique, has been largely replaced by noninvasive tests: impedance plethysmography, venous Doppler, /sup 125/I-radiofibrinogen-uptake test, and phleborheography. Virchow's triad of stasis, vessel injury, and hypercoagulability remains a valid explanation of the pathogenesis of thrombus formation, but laboratory and clinical data have refined our knowledge of how these factors interact to result in clinically significant disease. Knowledge of the natural history of venous thrombosis, plus heightened awareness of the long-term morbidity and expense associated with the postphlebitic syndrome, have led to increased interest in preventing DVT. Clinically and economically, venous thrombosis is best managed by prevention. 61 references.

  6. Venous ulcer review

    Science.gov (United States)

    Bevis, Paul; Earnshaw, Jonothan

    2011-01-01

    Clinical question: What is the best treatment for venous ulcers? Results: Compression aids ulcer healing. Pentoxifylline can aid ulcer healing. Artificial skin grafts are more effective than other skin grafts in helping ulcer healing. Correction of underlying venous incompetence reduces ulcer recurrence. Implementation: Potential pitfalls to avoid are: Failure to exclude underlying arterial disease before application of compression.Unusual-looking ulcers or those slow to heal should be biopsied to exclude malignant transformation. PMID:21673869

  7. Venous ulcer review

    OpenAIRE

    Bevis, Paul; Earnshaw, Jonothan

    2011-01-01

    Paul Bevis, Jonothan Earnshaw Department of Vascular Surgery, Gloucestershire Royal Hospital, Great Western Road, Gloucester, UKDate of preparation: 3 February 2011Conflict of interest: None declared.Clinical question: What is the best treatment for venous ulcers?Results: Compression aids ulcer healing. Pentoxifylline can aid ulcer healing. Artificial skin grafts are more effective than other skin grafts in helping ulcer healing. Correction of underlying venous incompetence reduces ulcer recu...

  8. A beam steering technique using dielectric wedges.

    OpenAIRE

    Khan, M. R.

    1995-01-01

    The thesis describes a method of' beam steering aimed at producing a useful amount of deflection of an antenna beam from boresight, by a simple and Inexpensive method. For large antennas, It is difficult, as well as expensive, to steer the beam by more than a few beamwidths. The method studied was developed with particular reference to the beam steering requirements of Direct Broadcast Satellite flat plate antennas. The method involves two dielectric wedges, having cir...

  9. Localization of observables in the Rindler wedge

    Science.gov (United States)

    Asorey, M.; Balachandran, A. P.; Marmo, G.; de Queiroz, A. R.

    2017-11-01

    One of the striking features of QED is that charged particles create a coherent cloud of photons. The resultant coherent state vectors of photons generate a nontrivial representation of the localized algebra of observables that do not support a representation of the Lorentz group: Lorentz symmetry is spontaneously broken. We show in particular that Lorentz boost generators diverge in this representation, a result shown also by Balachandran et al. [Eur. Phys. J. C 75, 89 (2015), 10.1140/epjc/s10052-015-3305-0] (see also the work by Balachandran et al. [Mod. Phys. Lett. A 28, 1350028 (2013), 10.1142/S0217732313500284]. Localization of observables, for example in the Rindler wedge, uses Poincaré invariance in an essential way [Int. J. Geom. Methods Mod. Phys. 14, 1740008 (2017)., 10.1142/S0219887817400084]. Hence, in the presence of charged fields, the photon observables cannot be localized in the Rindler wedge. These observations may have a bearing on the black hole information loss paradox, as the physics in the exterior of the black hole has points of resemblance to that in the Rindler wedge.

  10. Correlation of myocardial perfusion SPECT with invasive and computed tomography coronary angiogram.

    Science.gov (United States)

    Shelley, S; Indirani, M; Sathyamurthy, I; Subramanian, K; Priti, N; Harshad, K; Padma, D

    2012-01-01

    The consequences of atherosclerosis can be detected by multislice computed tomography (MSCT), invasive coronary angiogram (CAG) and the resultant myocardial ischaemia by myocardial perfusion single photon emission computed tomography (MPS). In this study an attempt is made to compare MSCT with MPS and also to compare the MSCT findings with that of invasive CAG in patients suspected to have coronary artery disease (CAD). A total of 99 patients suspected to have CAD underwent both MSCT and MPS with (99m)Tc sestamibi. The MSCT studies were classified as having no CAD, significant CAD (>50% diameter stenosis), and insignificant CAD (50% diameter stenosis). Multislice computed tomography correlated well in 46 (84%) with P value of 800). Myocardial perfusion single photon emission computed tomography was normal in 15 (27%) coronaries. Myocardial perfusion single photon emission computed tomography provides functional information of the anatomical lesions and MSCT provides anatomical information. Both are two different diagnostic modalities. The MSCT has high NPV in patients with less likelihood for CAD. When compared with CAG, the correlation with MSCT was good and is useful where the calcium score is low. Copyright © 2012 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  11. Dimensions of the foveal avascular zone using the Heidelberg retinal angiogram-2 in normal eyes

    Directory of Open Access Journals (Sweden)

    John Deepa

    2011-01-01

    Full Text Available Purpose: The purpose was to study the dimensions of the foveal avascular zone (FAZ using Heidelberg Retinal Angiogram-2 (HRA-2; Heidelberg Engineering GmBH, Dossenheim, Germany. Materials and Methods: An observational study of the FAZ area and circumference was done with fundus fluorescein angiography (FFA using HRA-2 in 31 normal individuals. The FAZ was studied using both contrast-adjusted and nonadjusted methods. Contrast adjustment was done to obtain better visualization of the finer capillaries around the fovea enabling more precise measurements of the FAZ in normal eyes. Results: The mean area of the FAZ calculated by the contrast-adjusted method was 0.2753 mm 2 (±0.074 and the mean circumference was 2.22 mm (±0.048. By the conventional method, the area and circumference of the FAZ were 0.6241 mm 2 (±0.177 and 3.23 mm (±0.454, respectively. Conclusion: The measurements of area and circumference of FAZ using contrast-adjusted methods were significantly smaller than the conventional method.

  12. Intensity-based 2-D-3-D registration of cerebral angiograms.

    Science.gov (United States)

    Hipwell, John H; Penney, Graeme P; McLaughlin, Robert A; Rhode, Kawal; Summers, Paul; Cox, Tim C; Byrne, James V; Noble, J Alison; Hawkes, David J

    2003-11-01

    We propose a new method for aligning three-dimensional (3-D) magnetic resonance angiography (MRA) with 2-D X-ray digital subtraction angiograms (DSA). Our method is developed from our algorithm to register computed tomography volumes to X-ray images based on intensity matching of digitally reconstructed radiographs (DRRs). To make the DSA and DRR more similar, we transform the MRA images to images of the vasculature and set to zero the contralateral side of the MRA to that imaged with DSA. We initialize the search for a match on a user defined circular region of interest. We have tested six similarity measures using both unsegmented MRA and three segmentation variants of the MRA. Registrations were carried out on images of a physical neuro-vascular phantom and images obtained during four neuro-vascular interventions. The most accurate and robust registrations were obtained using the pattern intensity, gradient difference, and gradient correlation similarity measures, when used in conjunction with the most sophisticated MRA segmentations. Using these measures, 95% of the phantom start positions and 82% of the clinical start positions were successfully registered. The lowest root mean square reprojection errors were 1.3 mm (standard deviation 0.6) for the phantom and 1.5 mm (standard deviation 0.9) for the clinical data sets. Finally, we present a novel method for the comparison of similarity measure performance using a technique borrowed from receiver operator characteristic analysis.

  13. A comparison of exact TM plane wave diffraction by coated wedges and impedance wedges

    DEFF Research Database (Denmark)

    Andersen, Lars S.; Breinbjerg, Olav; Moore, John T.

    1996-01-01

    of the SIBC wedge is based on Maliuzhinets' solution. Comparisons have been carried out for a series of configurations including lossy coatings as well as lossless coatings permitting unattenuated propagation of surface waves. The results show that the presence of an edge in a coated structure does...... without interference from direct fields or reflected fields. Results have been obtained in the case of illumination by a transverse magnetic (TM) uniform plane wave. The analysis of the coated wedge is based on an integral equation formulation combined with a hybrid technique, while the analysis...

  14. Customized CT angiogram planning for intraoperative transesophageal echography-guided endovascular exclusion of thoracic aorta penetrating ulcer.

    Science.gov (United States)

    Piazza, Michele; Lupia, Mario; Grego, Franco; Antonello, Michele

    2015-04-01

    The technique is demonstrated in a 78-year-old man; the preoperative CT angiogram showed a descending thoracic aorta ulcer of 5.9 cm in maximum diameter and 3.8 cm longitudinal extension. A ZTEG-2P-36-127-PF (Cook Medical) single tubular endograft was planned to be deployed. From the preoperative CT angiogram we planned to land 4.7 cm above the midline of the descending thoracic aorta ulcer and 8.0 cm below. In the operating room, under radioscopic vision the centre of the transesophageal echography probe was used as marker to identify the correspondent midline of the descending thoracic aorta ulcer and a centimeter-sized pigtail catheter in the aorta was used to calculate the desired length above and below the ulcer midline. The endograft was introduced and placed in the desired position compared to the transesophageal echography probe and the catheter; under transesophageal echography vision the graft was finally deployed. The CT angiogram at 1 month showed the correct endograft position, descending thoracic aorta ulcer exclusion with no signs of endoleak. In selected cases, this method allows planning in advance safe stent graft positioning and deployment totally assisted by transesophageal echography, with no risk of periprocedural contrast-related renal failure and reduced radiation exposure for the patient and operators. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  15. Hormonal contraception and venous thromboembolism

    DEFF Research Database (Denmark)

    Lidegaard, Øjvind; Milsom, Ian; Geirsson, Reynir Tomas

    2012-01-01

    New studies about the influence of hormonal contraception on the risk of venous thromboembolism (VTE) have been published.......New studies about the influence of hormonal contraception on the risk of venous thromboembolism (VTE) have been published....

  16. Pilot Study: Foam Wedge Chin Support Static Tolerance Testing

    Science.gov (United States)

    2017-10-24

    AFRL-SA-WP-SR-2017-0026 Pilot Study: Foam Wedge Chin Support Static Tolerance Testing Austin M. Fischer, BS1; William W...COVERED (From – To) April – October 2017 4. TITLE AND SUBTITLE Pilot Study: Foam Wedge Chin Support Static Tolerance Testing 5a. CONTRACT NUMBER...solution to this, Defence Research and Development Canada came up with a high-level concept of attaching a foam wedge to the chest to support the helmet

  17. Spontaneous coronary artery dissection: A retrospective analysis of 19,676 coronary angiograms

    Directory of Open Access Journals (Sweden)

    Dinesha Basavanna

    2017-01-01

    Full Text Available Aim: Spontaneous coronary artery dissection (SCAD is a rare cause of angina, myocardial infarction (MI, and sudden cardiac death (SCD and may frequently manifest as acute coronary syndrome (ACS. The diagnosis of SCAD relies on angiographic visualization of a radiolucent intimal flap. Therapeutic options include medical therapy, percutaneous coronary interventions, and bypass surgery. The aim of this study is to analyze the clinical profile, inhospital outcomes, management, and follow-up of patients with angiographic SCAD. Methods: About 19,676 diagnostic coronary angiograms (CAGs were reviewed retrospectively during a 2-year period; 64 patients had SCAD and were included in the study. Complete medical histories before and during the event as well as treatment regimens were obtained from patients' hospital files. Results: A total of 64 cases of SCAD were considered for the study within an age range of 25–70 years. Fifty-eight patients presented with ACS, two patients presented with unstable angina, one patient presented with rheumatic mitral stenosis in atrial fibrillation, one patient presented with non-ST-elevation myocardial infarction, one patient with dilated cardiomyopathy with left ventricular dysfunction, and one patient with effort. Out of 64 patients, four patients died and the average hospital stay is 3–5 days. Conclusion: SCAD occurs in 0.32% of patients undergoing CAG for evaluation of coronary artery disease. Majority of SCAD occurs in men. The left coronary artery is most commonly affected. The inhospital outcomes are good. Most of the patients with SCAD have good prognosis following optimal medical therapy.

  18. Detection of retinal capillary nonperfusion in fundus fluorescein angiogram of diabetic retinopathy.

    Science.gov (United States)

    Rasta, Seyed Hossein; Nikfarjam, Shima; Javadzadeh, Alireza

    2015-01-01

    Retinal capillary nonperfusion (CNP) is one of the retinal vascular diseases in diabetic retinopathy (DR) patients. As there is no comprehensive detection technique to recognize CNP areas, we proposed a different method for computing detection of ischemic retina, non-perfused (NP) regions, in fundus fluorescein angiogram (FFA) images. Whilst major vessels appear as ridges, non-perfused areas are usually observed as ponds that are surrounded by healthy capillaries in FFA images. A new technique using homomorphic filtering to correct light illumination and detect the ponds surrounded in healthy capillaries on FFA images was designed and applied on DR fundus images. These images were acquired from the diabetic patients who had referred to the Nikookari hospital and were diagnosed for diabetic retinopathy during one year. Our strategy was screening the whole image with a fixed window size, which is small enough to enclose areas with identified topographic characteristics. To discard false nominees, we also performed a thresholding operation on the screen and marked images. To validate its performance we applied our detection algorithm on 41 FFA diabetic retinopathy fundus images in which the CNP areas were manually delineated by three clinical experts. Lesions were found as smooth regions with very high uniformity, low entropy, and small intensity variations in FFA images. The results of automated detection method were compared with manually marked CNP areas so achieved sensitivity of 81%, specificity of 78%, and accuracy of 91%.The result was present as a Receiver operating character (ROC) curve, which has an area under the curve (AUC) of 0.796 with 95% confidence intervals. This technique introduced a new automated detection algorithm to recognize non-perfusion lesions on FFA. This has potential to assist detecting and managing of ischemic retina and may be incorporated into automated grading diabetic retinopathy structures.

  19. Qualitative assessment of contrast-enhanced magnetic resonance angiography using breath-hold and non-breath-hold techniques in the portal venous system

    Science.gov (United States)

    Goo, Eun-Hoe; Kim, Sun-Ju; Dong, Kyung-Rae; Kim, Kwang-Choul; Chung, Woon-Kwan

    2016-09-01

    The purpose of this study is to evaluate the image quality in delineation of the portal venous systems with two different methods, breath-hold and non-breath-hold by using the 3D FLASH sequence. We used a 1.5 T system to obtain magnetic resonance(MR)images. Arterial and portal phase 3D FLASH images were obtained with breath-hold after a bolus injection of GD-DOTA. The detection of PVS on the MR angiograms was classified into three grades. First, the angiograms of the breath-hold method showed well the portal vein, the splenic vein and the superior mesenteric vein systems in 13 of 15 patients (86%) and the inferior mesenteric vein system in 6 of 15 patients (40%), Second, MR angiograms of the non-breath-hold method demonstrated the PVS and the SMV in 12 of 15 patients (80%) and the IMV in 5 of 15 patients (33%). Our study showed contrast-enhanced 3D FLASH MR angiography, together with the breath-hold technique, may provide reliable and accurate information on the portal venous system.

  20. Models of the venous system

    DEFF Research Database (Denmark)

    Mehlsen, J

    2000-01-01

    of the venous system require at least three elements: a resistor, a capacitor and an inductor, with the latter being of more importance in the venous than in the arterial system. Non-linearities must be considered in pressure/flow relations in the small venules, during venous collapse, or low flow conditions...

  1. Feasibility of transfemoral hepatic vein/wedged portal venous pressure measurement in total artificial heart

    Directory of Open Access Journals (Sweden)

    Ashwani Kumar Sharma, MD

    2017-06-01

    Full Text Available The development of technology and limitation of numerous ventricular assist devices has increased usage of the total artificial heart (TAH for mechanical circulatory support. A primary important feature of TAH is that it is one of the few mechanical circulatory support devices that provides biventricular support. As the number of patients with TAH rises, spreading awareness about the device in the interventional radiology community is important.

  2. Venous oxygen saturation.

    Science.gov (United States)

    Hartog, Christiane; Bloos, Frank

    2014-12-01

    Early detection and rapid treatment of tissue hypoxia are important goals. Venous oxygen saturation is an indirect index of global oxygen supply-to-demand ratio. Central venous oxygen saturation (ScvO2) measurement has become a surrogate for mixed venous oxygen saturation (SvO2). ScvO2 is measured by a catheter placed in the superior vena cava. After results from a single-center study suggested that maintaining ScvO2 values >70% might improve survival rates in septic patients, international practice guidelines included this target in a bundle strategy to treat early sepsis. However, a recent multicenter study with >1500 patients found that the use of central hemodynamic and ScvO2 monitoring did not improve long-term survival when compared to the clinical assessment of the adequacy of circulation. It seems that if sepsis is recognized early, a rapid initiation of antibiotics and adequate fluid resuscitation are more important than measuring venous oxygen saturation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Experimental and numerical investigations on melamine wedges.

    Science.gov (United States)

    Schneider, S

    2008-09-01

    Melamine wedges are often used as acoustic lining material for anechoic chambers. It was proposed here to study the effects of the mounting conditions on the acoustic properties of the melamine wedges used in the large anechoic chamber at the LMA. The results of the impedance tube measurements carried out show that the mounting conditions must be taken into account when assessing the quality of an acoustic lining. As it can be difficult to simulate these mounting conditions in impedance tube experiments, a numerical method was developed, which can be used to complete the experiments or for parametric studies. By combining the finite and the boundary element method, it is possible to investigate acoustic linings with almost no restrictions as to the geometry, material behavior, or mounting conditions. The numerical method presented here was used to study the acoustic properties of the acoustic lining installed in the anechoic chamber at the LMA. Further experiments showed that the behavior of the melamine foam is anisotropic. Numerical simulations showed that this anisotropy can be used to advantage when designing an acoustic lining.

  4. Venous ulcer: what is new?

    Science.gov (United States)

    Raffetto, Joseph D; Marston, William A

    2011-01-01

    The pathophysiology of venous dermal abnormality in chronic venous ulcers is reflective of a complex interplay that involves sustained venous hypertension, inflammation, changes in the microcirculation, cytokine and matrix metalloproteinase activation, and altered cellular function. Red blood cells and macromolecules extravasate into the interstitium and activate endothelial cells. Endothelial expression of specific adhesion molecules recruits leukocytes and causes diapedesis of these cells into the dermal microvasculature, promoting an inflammatory response with activation of cytokines and proteinases. Altered cell function enhances a state of vulnerability in the surrounding tissues, initiating specific changes associated with venous disease. Ultimately, the persistent inflammatory-proteinase activity leads to advanced chronic venous insufficiency and ulcer formation. The mainstay of therapy in venous ulcer abnormality is correction of the underlying venous hypertension through compression therapy and/or surgery. Understanding the science involved in the pathophysiology of venous ulcer formation has led to the development of adjunctive treatment directed at the dysregulated molecular pathways. Randomized clinical trials are critical for determining the most effective evidence-based treatments for venous ulcer, and this review discusses important trials that have had a significant impact on venous ulcer healing. In addition, the authors have included subsections referred to as "Translational Implications for Therapy" in the basic science sections of the review to help bridge the basic science knowledge with clinical applications that may help to modulate the molecular abnormalities in the pathophysiologic cascade leading to venous ulcers.

  5. 307 Is Catheter Diagnostic Cerebral Angiography Still Essential for Patients With Spontaneous Perimesencephalic Subarachnoid Hemorrhage and Negative Computed Tomography Angiogram?

    Science.gov (United States)

    Galal, Ahmed; ElSerry, Tarek H; Aziz, Mohamed Mostafa

    2016-08-01

    Computed tomography (CT) angiography is currently used as the initial diagnostic tool in patients with spontaneous subarachnoid hemorrhage. Eighty-five percent of spontaneous subarachnoid hemorrhages are reported in the literature as caused by a ruptured aneurysm, whereas 10% are termed nonaneurysmal perimesencephalic subarachnoid hemorrhage and carry and excellent prognosis. This retrospective study was conducted to better clarify the diagnostic yield of transfemoral catheter cerebral angiography in light of the current high-quality CT angiogram imaging reported as negative in cases presenting with perimesencephalic subarachnoid hemorrhage. Patients with an admission diagnosis of perimesencephalic subarachnoid hemorrhage and a CT angiogram report as being negative from January 2013 to December 2015 were retrospectively reviewed. CT angiogram findings were correlated with that of the catheter-based diagnostic cerebral angiogram that was done at the time of presentation. Clinical data recorded included age, sex, medical history, and clinical presentation. The authors retrospectively reviewed CT brain, CT angiogram, and digital subtraction angiography images as well as formal reports. A total of 43 patients fulfilled the aforementioned diagnostic criteria of spontaneous perimesencephalic subarachnoid hemorrhage. There were 31 females and 12 males. Ages ranged from 23 to 69 years. All patients had Hunt and Hess grades I or II. There was a false-negative CT angiogram in 4 cases (9.3%) where an underlying aneurysm was identified on digital subtraction angiography, the site of which correlated with the pattern of bleeding. The mean aneurysm size was 2 mm. No complications were related to the catheter angiogram procedure. This study shows that CT angiography, even when read as "negative" for cases assumed to have a benign perimesencephalic pattern of subarachnoid hemorrhage, is still insufficient to exclude underlying pathology as the source of hemorrhage. This study

  6. Automatic segmentation of coronary angiograms based on fuzzy inferring and probabilistic tracking

    Directory of Open Access Journals (Sweden)

    Shoujun Zhou

    2010-08-01

    Full Text Available Abstract Background Segmentation of the coronary angiogram is important in computer-assisted artery motion analysis or reconstruction of 3D vascular structures from a single-plan or biplane angiographic system. Developing fully automated and accurate vessel segmentation algorithms is highly challenging, especially when extracting vascular structures with large variations in image intensities and noise, as well as with variable cross-sections or vascular lesions. Methods This paper presents a novel tracking method for automatic segmentation of the coronary artery tree in X-ray angiographic images, based on probabilistic vessel tracking and fuzzy structure pattern inferring. The method is composed of two main steps: preprocessing and tracking. In preprocessing, multiscale Gabor filtering and Hessian matrix analysis were used to enhance and extract vessel features from the original angiographic image, leading to a vessel feature map as well as a vessel direction map. In tracking, a seed point was first automatically detected by analyzing the vessel feature map. Subsequently, two operators [e.g., a probabilistic tracking operator (PTO and a vessel structure pattern detector (SPD] worked together based on the detected seed point to extract vessel segments or branches one at a time. The local structure pattern was inferred by a multi-feature based fuzzy inferring function employed in the SPD. The identified structure pattern, such as crossing or bifurcation, was used to control the tracking process, for example, to keep tracking the current segment or start tracking a new one, depending on the detected pattern. Results By appropriate integration of these advanced preprocessing and tracking steps, our tracking algorithm is able to extract both vessel axis lines and edge points, as well as measure the arterial diameters in various complicated cases. For example, it can walk across gaps along the longitudinal vessel direction, manage varying vessel

  7. Bow wave and spray dynamics by a wedge

    OpenAIRE

    Wang, Zhaoyuan; Yang, Jianming; Stern, Frederick

    2010-01-01

    Flows around a wedge-shaped bow are simulated with the aim of investigating the wave breaking mechanism and small scale features of ship bow waves. This fluid dynamics video shows the plunging wave breaking process around the wedge including the thin water sheet formation, overturning sheet with surface disturbance, fingering and breaking up into spray, plunging and splashing, and air entrainment.

  8. On size-effects in single crystal wedge indentation

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Kysar, Jeffrey W.

    2012-01-01

    Wedge indentation in single crystals is studied numerically, with emphasis on size-effects on the micron scale. Under the assumption of a perfectly sharp wedge indenter, a linear relationship between indentation force and indentation depth would be predicted from conventional theories lacking con...

  9. Comparison of wedge resection (Winograd procedure) and wedge resection plus complete nail plate avulsion in the treatment of ingrown toenails.

    Science.gov (United States)

    Huang, Jia-Zhang; Zhang, Yi-Jun; Ma, Xin; Wang, Xu; Zhang, Chao; Chen, Li

    2015-01-01

    The present retrospective study compared the efficacy of wedge resection (Winograd procedure) and wedge resection plus complete nail plate avulsion for the treatment of ingrown toenails (onychocryptosis). Two surgical methods were performed in 95 patients with a stage 2 or 3 ingrown toenail. Each patient was examined weekly until healing and then at 1, 6, and 12 months of follow-up. The outcomes measured were surgical duration, healing time, recurrence rate, the incidence of postoperative infection, and cosmetic appearance after surgery. Of the 95 patients (115 ingrown toenails) included in the present study, 39 (41.1%) underwent wedge resection (Winograd procedure) and 56 (59%), wedge resection plus complete nail plate avulsion. The mean surgical duration for wedge resection (Winograd procedure) and wedge resection plus complete nail plate avulsion was 14.9 ± 2.4 minutes and 15.1 ± 3.2 minutes, respectively (p = .73). The corresponding healing times were 2.8 ± 1.2 weeks and 2.7 ± 1.3 weeks (p = .70). Recurrence developed in 3 (3.2%) patients after wedge resection (Winograd procedure) and in 4 (4.2%) after wedge resection plus complete nail plate avulsion. In addition, postoperative infection occurred in 3 (3.2%) patients after wedge resection (Winograd procedure) and 2 (2.1%) after wedge resection plus complete nail plate avulsion. Both of the surgical procedures were practical and appropriate for the treatment of ingrown toenails, being simple and associated with low morbidity and a high success rate. However, cosmetically, wedge resection (Winograd procedure) would be the better choice because the nail plate remains intact. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  10. Ground penetrating radar estimates of permafrost ice wedge depth

    Science.gov (United States)

    Parsekian, A.; Slater, L. D.; Nolan, J. T.; Grosse, G.; Walter Anthony, K. M.

    2013-12-01

    Vertical ground ice wedges associated with polygonal patterning in permafrost environments form due to frost cracking of soils under harsh winter conditions and subsequent infilling of cracks with snow melt water. Ice wedge polygon patterns have implications for lowland geomorphology, hydrology, and vulnerability of permafrost to thaw. Ice wedge dimensions may exceed two meters width at the surface and several meters depth, however few studies have addressed the question of ice wedge depth due to challenges related to measuring the vertical dimension below the ground. Vertical exposures where ice wedges maybe observed are limited to rapidly retreating lake, river, and coastal bluffs. Coring though the ice wedges to determine vertical extent is possible, however that approach is time consuming and labor intensive. Many geophysical investigations have noted signal anomalies related to the presence of ice wedges, but no reliable method for extracting wedge dimensions from geophysical data has been yet proposed. Here we present new evidence that ground penetrating radar (GPR) may be a viable method for estimating ice wedge depth. We present three new perspectives on processing GPR data collected over ice wedges that show considerable promise for use as a fast, cost effective method for evaluating ice wedge depth. Our novel approaches include 1) a simple frequency-domain analysis, 2) an S-transform frequency domain analysis and 3) an analysis of the returned signal power as a radar cross section (RCS) treating subsurface ice wedges as dihedral corner retro-reflectors. Our methods are demonstrated and validated using finite-difference time domain FDTD) GPR forward models of synthetic idealized ice wedges and field data from permafrost sites in Alaska. Our results indicate that frequency domain and signal power data provide information that is easier to extract from raw GPR data than similar information in the time domain. We also show that we can simplify the problem by

  11. Genetics in chronic venous disease.

    Science.gov (United States)

    Grant, Yasmin; Onida, Sarah; Davies, Alun

    2017-02-01

    Chronic venous disease is highly prevalent in the Western world, with varicose veins being the most common form of clinical manifestation. With recent developments in sequencing technology, clinicians and geneticists alike are embarking on a journey to identify and unravel the genetic candidates of chronic venous disease. There is now currently substantial evidence to suggest the presence of genetic influences in the aetiology and pathology of venous disease. Despite this, the precise nature and profile of the genes involved in chronic venous disease remain a poorly understood entity. Moreover, it is strikingly apparent that the majority of venous genetic studies conducted over the past decade do not adhere to fundamental research principles. The emergence of high-throughput genotyping platforms permits a more systematic search for inherited components of venous disease. Pursuing a genome-wide frontier has the potential to reveal novel critical metabolic pathways and explain the genetic susceptibility of chronic venous disease. An expedited knowledge of the genetic factors in the aetiology of venous disease may translate into better prevention or treatment, which would benefit patients suffering from its clinical sequelae. Researchers should be urged to foster collaborative links and design a genome-wide case-control association study as an international consortium to provide a statistically robust paradigm in the field of chronic venous disease genetics. This will carry promise for clinically relevant progress and represent a first step towards better understanding of the genetics of chronic venous disease aetiology.

  12. Seamount subduction underneath an accretionary wedge: modelling mass wasting and wedge collapse

    Science.gov (United States)

    Mannu, Utsav; Ueda, Kosuke; Willett, Sean; Gerya, Taras; Strasser, Michael

    2017-04-01

    Seamounts (h >1 km) and knolls (h = 500 m-1000 m) cover about one-fifth of the total ocean floor area. These topographical highs of the ocean floor eventually get subducted. Subduction of these topographical features leads to severe deformation of the overriding plate and can cause extensive tectonic erosion and mass wasting of the frontal prism, which can ultimately cause a forearc wedge collapse. Large submarine landslides and the corresponding wedge collapse have previously been reported, for instance, in the northern part of the Hikurangi margin where the landslide is known as the giant Ruatoria debris avalanche, and have also been frequently reported in several seismic sections along the Costa Rica margin. Size and frequency relation of landslides suggest that the average size of submarine landslides in margins with rough subducting plates tends to be larger. However, this observation has not yet been tested or explained by physical models. In numerical subduction models, landslides take place, if at all, on a much larger timescale (in the order of 104-105 years, depending on the time steps of the model) than in natural cases. On the other hand, numerical models simulating mass wasting events such as avalanches and submarine landslides, typically model single events at a much smaller spatio-temporal domain, and do not consider long-term occurrence patterns of freely forming landslides. In this contribution, we present a multi-scale nested numerical approach to emulate short-term landslides within long-term progressive subduction. The numerical approach dynamically produces instantaneous submarine landslides and the resulting debris flow in the spatially and temporally refined inner model. Then we apply these convoluted changes in topography (e.g. due to the submarine landslide etc.) back to an outer larger-scale model instance that addresses wedge evolution. We use this approach to study the evolution of the accretionary wedge during seamount subduction.

  13. Location of Radicular Spinal Arteries in the Lumbar Spine from Analysis of CT Angiograms of the Abdomen and Pelvis.

    Science.gov (United States)

    Simon, Jeremy I; McAuliffe, Matthew; Smoger, David

    2016-01-01

    Reports of catastrophic neurologic injuries following lumbar transforaminal epidural steroid injections are rare but serious potential complications. The traditional method of performing lumbar transforaminal epidural steroid injections is in the "safe triangle" to avoid contact to the spinal nerve. Some authors advocate an alternative approach by placing the needle inferiorly in a region referred to as "Kambin's triangle" to avoid incurring arteries. This study aimed to determine the location of arteries within the L1-L4 intervertebral foramen in vivo, specifically if they lie within or in close proximity to the "safe triangle" or Kambin's triangle using CT angiograms of the abdomen and pelvis. The authors retrospectively evaluated the location in vivo of arterial vessels in the intervertebral foramen from L1 to L4 in patients who underwent abdominopelvic CT angiograms for aortic vascular disease. The data were reanalyzed to confirm inter-rater reliability. Arteries were found in both the safe triangle and Kambin's triangle at a statistically significant rate (P triangle or in Kambin's triangle frequently, suggesting the location of these arteries can be quite variable. Physicians performing these procedures should use universal precautions to avoid inadvertent injection into the lumbar spinal arteries and minimize potential complications regardless of the approach. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. 2016. This work is written by US Government employees and is in the public domain in the US.

  14. Understanding Guyton's venous return curves

    National Research Council Canada - National Science Library

    Beard, Daniel A; Feigl, Eric O

    2011-01-01

    ...) was experimentally increased the right atrial pressure decreased, Arthur Guyton and coworkers proposed an interpretation that right atrial pressure represents a back pressure restricting venous return...

  15. Octave spanning wedge dispersive mirrors with low dispersion oscillations.

    Science.gov (United States)

    Habel, Florian; Shirvanyan, Vage; Trubetskov, Michael; Burger, Christian; Sommer, Annkatrin; Kling, Matthias F; Schultze, Martin; Pervak, Vladimir

    2016-05-02

    A novel concept for octave spanning dispersive mirrors with low spectral dispersion oscillations is presented. The key element of the so-called wedge dispersive mirror is a slightly wedged layer which is coated on a specially optimized dispersive multilayer stack by a common sputter coating process. The group delay dispersion (GDD) of a pulse reflected on a wedge dispersive mirror is nearly free of oscillations. Fabricated mirrors with negative GDD demonstrate the compression of a pulse down to 3.8 fs as good as double angled mirrors optimized for the same bandwidth.

  16. Venous function after pharmacomechanical thrombolysis for ...

    African Journals Online (AJOL)

    Background: Chronic venous insufficiency is an important complication following iliofemoral deep venous thrombosis. Early thrombus removal may preserve venous function and prevent this complication. This study represents the largest reported South African series of pharmacomechanical thrombolysis for iliofemoral ...

  17. Medullary Venous Hypertension Secondary to a Petrous Apex Dural Arteriovenous Fistula: A Case Report

    Directory of Open Access Journals (Sweden)

    Meghan Murphy

    2012-11-01

    Full Text Available Background: Dural arteriovenous fistulae (dAVF are common intracranial vascular lesions typically becoming symptomatic with cortical venous hypertension and possible hemorrhage. Here, we present a case illustration of a petrous apex dAVF with marked medullary venous hypertension and a unique clinical presentation. Methods: Case report. Results: A 72-year-old female, whose clinical progression was significant for altered mental status and progressive weakness, presented with diplopia, right leg paresis, and ataxia. Magnetic resonance imaging revealed edema involving the medulla. On digital subtraction cerebral angiogram, the patient was found to have a petrous apex dAVF, Cognard type IV. Following treatment with Onyx embolization, her symptoms rapidly improved, with complete resolution of diplopia and drastic improvement of her ataxia. Conclusion: The importance of this case is in the presentation and deterioration of the clinical exam, resembling an acute ischemic event. Further, this case illustrates that dAVF may cause venous hypertension with rapid onset of focal neurologic symptoms not exclusive to cortical locations.

  18. Wedge Heat-Flux Indicators for Flash Thermography

    Science.gov (United States)

    Koshti, Ajay M.

    2003-01-01

    Wedge indicators have been proposed for measuring thermal radiation that impinges on specimens illuminated by flash lamps for thermographic inspection. Heat fluxes measured by use of these indicators would be used, along with known thermal, radiative, and geometric properties of the specimens, to estimate peak flash temperatures on the specimen surfaces. These indicators would be inexpensive alternatives to high-speed infrared pyrometers, which would otherwise be needed for measuring peak flash surface temperatures. The wedge is made from any suitable homogenous material such as plastic. The choice of material is governed by the equation given. One side of the wedge is covered by a temperature sensitive compound that decomposes irreversibly when its temperature exceeds a rated temperature (T-rated). The uncoated side would be positioned alongside or in place of the specimen and exposed to the flash, then the wedge thickness at the boundary between the white and blackened portions measured.

  19. Reactive Atom Plasma Processing of Slumped Glass Wedges Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Reactive Atom Plasma (RAPTM) process will be evaluated as a rapid and practical method for fabricating precision wedges in glass sheets. The glass sheets are to...

  20. Central venous catheter - dressing change

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000156.htm Central venous catheter - dressing change To use the sharing features on this page, please enable JavaScript. You have a central venous catheter. This is a tube that goes into a ...

  1. Chronic Venous Disease under pressure

    NARCIS (Netherlands)

    S.W.I. Reeder (Suzan)

    2013-01-01

    textabstractIn chapter 1 we provide a general introduction of this thesis. Chronic venous disease (CVD) is a common medical condition that affects 2-64% of the worldwide population and leads to leg ulcers in 1% of the Western population. Venous leg ulceration (VLU) has an unfavorable prognosis with

  2. Venous Thromboembolism in Adolescents

    Directory of Open Access Journals (Sweden)

    Aneta Samková

    2012-01-01

    Full Text Available The incidence of venous thromboembolism (VTE during childhood is low with two peaks – neonatal and adolescent age. This retrospective study is focused on clinical characteristics of VTE during adolescence. The main goals are to assess the most frequent inherited and acquired risk factors and to evaluate the benefit of D-dimers in diagnostics of venous thromboemblism. The data of 18 adolescents were analysed – 16 girls (88.9%, 2 boys (11.1%. In 9 patients (50% thrombosis of the lower limb deep veins was diagnosed, six patients (33.3% suffered from symptomatic pulmonary embolism (PE and 3 patients (16.7% from thrombosis at unusual sites. One patient had an idiopathic VTE, the mean number of the inherited and acquired risk factors was 2.6. The most frequent inherited risk factor was Leiden mutation of factor V (27.8%. The most frequent acquired risk factor was oral contraception (OC in 12 out of 16 girls (75%. All of our patients on oral contraception had one or more additional risk factors. 10 out of 18 (55.6% patients with VTE had elevated activity of factor VIII. The sensitivity of D-dimers was low (50% in patients with distal lower limb thrombosis, but very high (100% in patients with PE.

  3. Ice-wedge volume calculation in Yedoma and thermokarst deposits

    OpenAIRE

    Ulrich, Mathias; Grosse, Guido; Strauss, Jens; Schirrmeister, Lutz

    2014-01-01

    Detailed calculations of ground-ice volumes in permafrost deposits are necessary to understand and quantify the response of permafrost landscapes to thermal disturbance and thawing. Ice wedges with their polygonal surface expression are a widespread ground-ice component of permafrost lowlands. Therefore, the wedge-ice volume (WIV) is one of the major factors to be considered, both for assessing permafrost vulnerability and for quantifying deep permafrost soil carbon inventories. Here, a strai...

  4. Scattering of wedges and cones with impedance boundary conditions

    CERN Document Server

    Lyalinov, Mikhail

    2012-01-01

    This book is a systematic and detailed exposition of different analytical techniques used in studying two of the canonical problems, the wave scattering by wedges or cones with impedance boundary conditions. It is the first reference on novel, highly efficient analytical-numerical approaches for wave diffraction by impedance wedges or cones. The applicability of the reported solution procedures and formulae to existing software packages designed for real-world high-frequency problems encountered in antenna, wave propagation, and radar cross section.

  5. Is subendocardial ischaemia present in patients with chest pain and normal coronary angiograms? A cardiovascular MR study.

    Science.gov (United States)

    Vermeltfoort, Ilse A C; Bondarenko, Olga; Raijmakers, Pieter G H M; Odekerken, Diego A M; Kuijper, Aaf F M; Zwijnenburg, Anton; van der Vis-Melsen, Mary J E; Twisk, Jos W R; Beek, Aernout M; Teule, Gerrit J J; van Rossum, Albert C

    2007-07-01

    On the basis of an MRI study it has been suggested that subendocardial hypoperfusion is present in patients with cardiac syndrome X. However, further work is required to test whether these findings can be generalized. MRI was used to visually and semi-quantitatively assess subendocardial and subepicardial perfusion, at rest and during an infusion of adenosine, in 20 patients with angina pectoris and normal coronary angiograms. A myocardial perfusion index (MPI) was calculated using the normalized upslope of myocardial signal enhancement. An index for myocardial perfusion reserve (MPRI) was calculated by dividing the MPI values at maximal vasodilatation by the values at rest. The MPI in our study population increased significantly during adenosine infusion in both the subendocardium (from 0.091 +/- 0.020 to 0.143 +/- 0.030; P subendocardial hypoperfusion in these patients.

  6. Combined arterial and venous whole-body MR angiography with cardiac MR imaging in patients with thromboembolic disease - initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, Florian M.; Hunold, Peter; Barkhausen, Joerg [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Herborn, Christoph U. [University Hospital Hamburg-Eppendorf, Medical Prevention Center Hamburg (MPCH) at University Hospital Hamburg-Eppendorf, Hamburg (Germany); Ruehm, Stefan G. [David Geffen School of Medicine at UCLA, Department of Radiology, Los Angeles, CA (United States); Kroger, Knut [University Hospital Essen, Department of Angiology, Essen (Germany)

    2008-05-15

    The objective was to assess the feasibility of a combined arterial and venous whole-body three-dimensional magnetic resonance (MR) angiography, together with a cardiac MR examination, in patients with arterial thromboembolism. Ten patients with arterial thromboembolism underwent a contrast-enhanced whole-body MR examination of the arterial and venous vessels, followed by a cardiac MR examination on a separate occasion within 24 h. All examinations were performed on a 1.5-T MR scanner. For both arterial and venous MR angiography only one injection of contrast agent was necessary. The cardiac imaging protocol included dark-blood-prepared half-Fourier acquisition single-shot turbo-spin-echo sequences, fast steady-state free precession cine sequences, T2-weighted turbo-spin-echo sequences and inversion recovery gradient-echo fast low-angle-shot sequences after injection of contrast agent. MR imaging revealed additional clinically unknown arterial thromboembolisms in four patients. The thoracic aorta was depicted as embolic source in four patients, while deep vein thrombosis (DVT) was found in one patient as the underlying disease. Unsuspected infarction of parenchymal organs was detected by MRI in two patients. An unknown additional DVT was found in one patient. Four patients were considered to have arterial emboli of cardiac origin. In conclusion, acquisition of arterial and venous MR angiograms of the entire vascular system combined with cardiac MR imaging is a most comprehensive and valuable strategy in patients with arterial thromboembolism. (orig.)

  7. Cerebral venous thrombosis.

    Science.gov (United States)

    Ferro, José Manuel; Canhão, Patrícia; Aguiar de Sousa, Diana

    2016-12-01

    Cerebral venous thrombosis (CVT) has an incidence of 1.32/100,000/years in high-income countries, and higher in middle- and low-income countries. CVT is more frequent in infants and children young adults and females, especially during pregnancy/puerperium. CVT are now being diagnosed with increasing frequency because of the increased awareness and higher use of magnetic resonance imaging (MR) for investigating patients with acute and subacute headaches and new onset seizures. CVT rarely present as a stroke syndrome. Their most frequent presentations are isolated headache, intracranial hypertension syndrome, seizures, a lobar syndrome and encephalopathy. The confirmation of the diagnosis of CVT relies on the demonstration of thrombi in the cerebral veins and/or sinuses by MR/MR venography or veno CT. The more frequent risk factors/associated conditions for CVT are genetic prothrombotic conditions, antiphospholipid syndrome and other acquired prothrombotic diseases, including cancer, oral contraceptives, puerperium and pregnancy, infections and trauma. The prognosis of CVT is in general favorable, as acute death rate is below 5% and only 15% of the patients remain dependent or die. Treatment in the acute phase includes management of the associated condition, anticoagulation with either low molecular weight or unfractionated heparin, treatment of intracranial hypertension, prevention of recurrent seizures and headache relief. In patients in severe condition on admission or who deteriorate despite anticoagulation, local thrombolysis or thrombectomy is an option. Decompressive surgery is lifesaving in patients with large venous infarcts or hemorrhage with impending herniation. After the acute phase, patients should anticoagulated for a variable period of time, depending on their inherent thrombotic risk. CVT patients may experience recurrent seizures. Prophylaxis with anti-epileptic drugs is recommended after the first seizure, in those with hemispheric lesions. There

  8. Venous chest anatomy: clinical implications.

    Science.gov (United States)

    Chasen, M H; Charnsangavej, C

    1998-03-01

    This article provides a practical approach to the clinical implications and importance of understanding the collateral venous anatomy of the thorax. Routine radiography, conventional venography, computed tomography (CT), and magnetic resonance (MR) imaging studies provide correlative anatomic models for the demonstration of how interconnecting collateral vascular networks within the thorax maintain venous stability at all times. Five major systems comprise the collateral venous network of the thorax (Fig. 1). These include the paravertebral, azygos-hemiazygos, internal mammary, lateral thoracic, and anterior jugular venous systems (AJVS). The five systems are presented in the following sequence: (a) a brief introduction to the importance of catheter position and malposition in understanding access to the thoracic venous system, (b) the anatomy of the azygos-hemiazygos systems and their relationship with the paravertebral plexus, (c) the importance of the AJVS, (d) 'loop' concepts interconnecting the internal mammary and azygos-hemiazygos systems by means of the lateral thoracic and intercostal veins, and (e) the interconnecting venous networks on the thoracic side of the thoracoabdominal junction. Certain aspects of the venous anatomy of the thorax will not be discussed in this chapter and include (a) the intra-abdominal anastomoses between the superior and inferior vena cavae (IVC) via the internal mammary, lateral thoracic, and azygos-hemiazygos systems (beyond the scope of this article), (b) potential collateral vessels involving vertebral, parascapular, thyroidal, thymic, and other smaller veins that might anastomose with the major systems, and (c) anatomic variants and pitfalls that may mimic pathologic conditions (space limitations).

  9. Doppler ultrasound study and venous mapping in chronic venous insufficiency.

    Science.gov (United States)

    García Carriazo, M; Gómez de las Heras, C; Mármol Vázquez, P; Ramos Solís, M F

    2016-01-01

    Chronic venous insufficiency of the lower limbs is very prevalent. In recent decades, Doppler ultrasound has become the method of choice to study this condition, and it is considered essential when surgery is indicated. This article aims to establish a method for the examination, including venous mapping and preoperative marking. To this end, we review the venous anatomy of the lower limbs and the pathophysiology of chronic venous insufficiency and explain the basic hemodynamic concepts and the terminology required to elaborate a radiological report that will enable appropriate treatment planning and communication with other specialists. We briefly explain the CHIVA (the acronym for the French term "cure conservatrice et hémodynamique de l'insuffisance veineuse en ambulatoire"=conservative hemodynamic treatment for chronic venous insufficiency) strategy, a minimally invasive surgical strategy that aims to restore correct venous hemodynamics without resecting the saphenous vein. Copyright © 2015 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  10. The evolving energy budget of accretionary wedges

    Science.gov (United States)

    McBeck, Jessica; Cooke, Michele; Maillot, Bertrand; Souloumiac, Pauline

    2017-04-01

    The energy budget of evolving accretionary systems reveals how deformational processes partition energy as faults slip, topography uplifts, and layer-parallel shortening produces distributed off-fault deformation. The energy budget provides a quantitative framework for evaluating the energetic contribution or consumption of diverse deformation mechanisms. We investigate energy partitioning in evolving accretionary prisms by synthesizing data from physical sand accretion experiments and numerical accretion simulations. We incorporate incremental strain fields and cumulative force measurements from two suites of experiments to design numerical simulations that represent accretionary wedges with stronger and weaker detachment faults. One suite of the physical experiments includes a basal glass bead layer and the other does not. Two physical experiments within each suite implement different boundary conditions (stable base versus moving base configuration). Synthesizing observations from the differing base configurations reduces the influence of sidewall friction because the force vector produced by sidewall friction points in opposite directions depending on whether the base is fixed or moving. With the numerical simulations, we calculate the energy budget at two stages of accretion: at the maximum force preceding the development of the first thrust pair, and at the minimum force following the development of the pair. To identify the appropriate combination of material and fault properties to apply in the simulations, we systematically vary the Young's modulus and the fault static and dynamic friction coefficients in numerical accretion simulations, and identify the set of parameters that minimizes the misfit between the normal force measured on the physical backwall and the numerically simulated force. Following this derivation of the appropriate material and fault properties, we calculate the components of the work budget in the numerical simulations and in the

  11. Central Venous Catheter (Central Line)

    Science.gov (United States)

    ... venous catheter (KATHeter), also known as a central line or CVC, is long, soft, thin, hollow tube ... into a large vein (blood vessel). A central line is much like an intravenous (IV) catheter that ...

  12. Clinical overview of venous thromboembolism

    African Journals Online (AJOL)

    circulation, causing either partial or complete obstruction of pulmonary blood flow (in 4–13% of ... Keywords:anticoagulants, deep vein thrombosis, DVT, embolus, NOAC, PE, pulmonary embolism, thromboprophylaxis, thrombus, venous thromboembolism ... Cigarette smoking, including passive smoking. Hypercoagulability ...

  13. Heritability of chronic venous disease

    OpenAIRE

    Fiebig, Andreas; Krusche, Petra; De Wolf, Andreas; Krawczak, Michael; Timm, Birgitt; Nikolaus, Susanna; Frings, Norbert; Schreiber, Stefan

    2010-01-01

    Varicose veins without skin changes have a prevalence of approximately 20% in Northern and Western Europe whereas advanced chronic venous insufficiency affects about 3% of the population. Genetic risk factors are thought to play an important role in the aetiology of both these chronic venous diseases (CVD). We evaluated the relative genetic and environmental impact upon CVD risk by estimating the heritability of the disease in 4,033 nuclear families, comprising 16,434 individuals from all ove...

  14. Beam characteristics of upper and lower physical wedge systems of Varian accelerators

    Science.gov (United States)

    Cheng, Chee-Wai; Tang, Walter L.; Das, Indra J.

    2003-11-01

    The beam characteristics of a dual physical wedge system, upper and lower, for Varian accelerators are studied over the energy range 6-18 MV. Wedge factors for both systems are measured in a water phantom as a function of field size, depth and source-to-wedge (SWD) distance. Our results indicate that apart from their physical differences, dosimetrically, the two wedge systems have percentage depth dose beyond the build-up region. The lower wedge central axis percentage depth dose is consistently lower than that of the corresponding upper wedge, with the effect more pronounced for large field sizes. The wedge profiles are identical within 2% for all field sizes, depths and energies. The wedge factors for both wedge systems are also within 2% for all field sizes and depths for both 6 and 15 MV photons and slightly higher for the 18 MV beam and 45°-60° wedge angle. The wedge factor variation with SWD reveals an interesting fact that thinner wedges (15° and 30°) result in a higher surface dose in the central axis region than thicker wedges. As the SWD increases beyond 80 cm, the reverse is true, i.e. thicker wedges produce higher surface dose than thinner wedges. It is also verified that the wedge factor at any depth and for any field size can be calculated from the wedged and open field central axis percentage depth dose, and the wedge factor at dmax, resulting in nearly 44% reduction in water phantom scanning and 80% reduction in point measurements during commissioning.

  15. Neonatal Venous Thromboembolism

    Directory of Open Access Journals (Sweden)

    Kristina M. Haley

    2017-06-01

    Full Text Available Neonates are the pediatric population at highest risk for development of venous thromboembolism (VTE, and the incidence of VTE in the neonatal population is increasing. This is especially true in the critically ill population. Several large studies indicate that the incidence of neonatal VTE is up almost threefold in the last two decades. Central lines, fluid fluctuations, sepsis, liver dysfunction, and inflammation contribute to the risk profile for VTE development in ill neonates. In addition, the neonatal hemostatic system is different from that of older children and adults. Platelet function, pro- and anticoagulant proteins concentrations, and fibrinolytic pathway protein concentrations are developmentally regulated and generate a hemostatic homeostasis that is unique to the neonatal time period. The clinical picture of a critically ill neonate combined with the physiologically distinct neonatal hemostatic system easily fulfills the criteria for Virchow’s triad with venous stasis, hypercoagulability, and endothelial injury and puts the neonatal patient at risk for VTE development. The presentation of a VTE in a neonate is similar to that of older children or adults and is dependent upon location of the VTE. Ultrasound is the most common diagnostic tool employed in identifying neonatal VTE, but relatively small vessels of the neonate as well as frequent low pulse pressure can make ultrasound less reliable. The diagnosis of a thrombophilic disorder in the neonatal population is unlikely to change management or outcome, and the role of thrombophilia testing in this population requires further study. Treatment of neonatal VTE is aimed at reducing VTE-associated morbidity and mortality. Recommendations for treating, though, cannot be extrapolated from guidelines for older children or adults. Neonates are at risk for bleeding complications, particularly younger neonates with more fragile intracranial vessels. Developmental alterations in the

  16. Management of venous hypertension following arteriovenous fistula creation for hemodialysis access

    Directory of Open Access Journals (Sweden)

    Varun Mittal

    2016-01-01

    Full Text Available Introduction: Venous hypertension (VH is a distressing complication following the creation of arteriovenous fistula (AVF. The aim of management is to relieve edema with preservation of AVF. Extensive edema increases surgical morbidity with the loss of hemodialysis access. We present our experience in management of VH. Methods: A retrospective study was conducted on 37 patients with VH managed between July 2005 to May 2014. Patient demographics, evaluation, and procedures performed were noted. A successful outcome of management with surgical ligation (SL, angioembolization (AE, balloon dilatation (BD or endovascular stent (EVS was defined by immediate disappearance of thrill and murmur with resolution of edema in the next 48-72 h, no demonstrable flow during check angiogram and resolution of edema with preservation of AVF respectively. Results: All 8 distal AVF had peripheral venous stenosis and were managed with SL in 7 and BD in one patient. In 29 proximal AVF, central and peripheral venous stenosis was present in 16 and 13 patients respectively. SL, AE, BD, and BD with EVS were done in 18, 5, 4, and 3 patients, respectively. All patients had a successful outcome. SL was associated with wound related complications in 11 (29.73 % patients. A total of 7 AVF were salvaged. One had restenosis after BD and was managed with AE. BD, EVS, and AE had no associated morbidity. Conclusions: Management of central and peripheral venous stenosis with VH should be individualized and in selected cases it seems preferable to secure a new access in another limb and close the native AVF in edematous limb for better overall outcome.

  17. The Doppler-guided transfalcine venous approach in selected cases of vein of Galen malformations.

    Science.gov (United States)

    Benes, L; Wakat, J-P; Jüttner, J; Riegel, T; Krischek, B; Bertalanffy, H; Bien, S

    2003-01-01

    This investigation was performed to evaluate the specific procedural issues and indications of a surgically assisted Doppler-guided endovascular transfalcine venous approach for the treatment of vein of Galen aneurysmal malformations (VGAM) in critically ill neonates. Two neonates out of a clinical series of 15 children (8 males and 7 females) with vein of Galen malformations were treated by our neurovascular team, using a combined surgically assisted endovascular transfalcine approach. In the biplanar angiography room a radiographically guided craniotomy (1.5 cm) was placed over the cranial projection of the falciforme sinus. After craniotomy the orthograd flow of the falciforme sinus was identified by Doppler ultrasonography. The sinus was punctured by an i. v. cannula with injection port and was sutured to the skin. A microcatheter was maneuvered over a guide into the malformation under fluoroscopic control. For embolization Guglielmi electrolytically detachable platinum coils were placed into the malformation as an embolic agent. Neurological examination records, available MR images, computed tomographic scans, pre- and postembolization angiograms and follow-up data were analyzed. In both individuals the malformation was classified as VGAM. The follow-up was 6 and 7 months, respectively. No technique associated morbidity or mortality occurred in the present series. At discharge both selected neonates were in stable condition and the flow in the VGAMs could be significantly reduced by a combination of approaches including the venous transfalcine approach. Meanwhile, 6 months after birth one neonate died due to a deterioration of the pulmonary hypertension. Endovascular treatment is presently the most efficient strategy to allow neonates and infants survive the early manifestation of vein of Galen malformations and probably render a normal neurological development. Consequently, a combination of approaches in selected cases including the Doppler guided venous

  18. Angiographic suppression of the artery of Adamkiewicz by venous hypertension resolving after embolization in a case of spinal epidural arteriovenous fistula

    Science.gov (United States)

    Eckart Sorte, Danielle; Pardo, Carlos A; Gailloud, Philippe

    2014-01-01

    A case of complete angiographic suppression of the artery of Adamkiewicz and anterior spinal artery in a patient with a spinal epidural arteriovenous fistula (AVF) is reported. Slow flow AVFs typically present with progressive myelopathy secondary to spinal venous hypertension (SVH). The lack of a normal venous phase during angiography and its restoration after treatment is commonly observed with these lesions, yet a similar phenomenon seems exceptional at the arterial level. Right T11 intercostal artery angiograms obtained before and after treatment of a left L4 epidural AVF documented the initial suppression of the artery of Adamkiewicz and anterior spinal artery, and their normal appearance immediately after correction of the SVH by embolization. This report confirms that SVH can angiographically suppress prominent and functionally important spinal arteries, re-emphasizing the potential role played by secondary arterial changes in SVH induced myelopathy. This hemodynamic phenomenon also represents a potential pitfall during diagnostic and therapeutic endovascular procedures. PMID:25028420

  19. Tax wedge in Croatia, Belgium, Estonia, Germany and Slovakia

    Directory of Open Access Journals (Sweden)

    Ana Gabrilo

    2016-06-01

    Full Text Available The aim of this paper is to analyse the taxation of labour income in Croatia, Belgium,Estonia, Germany and Slovakia. Having presented an outline of tax system rules, the paper shows the decomposition of the net average tax wedge for different family types and different income levels based on the OECD methodology. The results show that all observed countries apply a progressive tax schedule, apart from Germany where taxation for higher gross wages is not progressive due to a  cap on the SIC base. When it comes to a taxpayer earning an average gross wage, a Croatian single worker without children has the lowest tax burden, followed by Estonia, Slovakia, Germany and Belgium. However, as regards taxpayers earning 400% of AGW, Estonia has the smallest tax wedge, followed by Slovakia, Germany, Croatia and Belgium. Similar results are obtained by analyzing the tax wedge for couples with two children where one spouse is out of work.

  20. Laparoscopic caecal wedge resection with intraoperative endoscopic assistance.

    Science.gov (United States)

    Giavarini, Luisa; Boni, Luigi; Cortellezzi, Camillo Claudio; Segato, Sergio; Cassinotti, Elisa; Rausei, Stefano; Dionigi, Gianlorenzo; Rovera, Francesca; Marzorati, Alessandro; Spampatti, Sebastiano; Sambucci, Daniele; Dionigi, Renzo

    2013-01-01

    Cancer is a potential evolution of adenomatous polyps, that is why nowadays screening programs for colorectal cancer are widely diffused. Colonoscopy is the gold standard procedure for identifying and resecting polyps; however, for some polyps resection during colonoscopy is not possible. The aim of the present study is to identify a fast and safe procedure for endoscopically resecting unresectable polyps. Patients with endoscopically unresectable polyps were scheduled for laparoscopic wedge resection under colonoscopic assistance. From November 2010 to November 2012 we treated 15 patients with endoscopically unresectable adenomatous polyps. All patients underwent a laparoscopic caecal wedge resection with intraoperative endoscopic assistance. All procedures were completed without complications and in all cases complete resection of the polyps was achieved. Laparoscopic wedge caecal resection with intraoperative colonoscopy is a fast and safe procedure that can be performed for large polyps that could not be treated endoscopically. Copyright © 2013 Elsevier Ltd and Surgical Associates Ltd. All rights reserved.

  1. Modeling and Stability Analysis of Wedge Clutch System

    Directory of Open Access Journals (Sweden)

    Jian Yao

    2014-01-01

    Full Text Available A wedge clutch with unique features of self-reinforcement and small actuation force was designed. Its self-reinforcement feature, associated with different factors such as the wedge angle and friction coefficient, brings different dynamics and unstable problem with improper parameters. To analyze this system, a complete mathematical model of the actuation system is built, which includes the DC motor, the wedge mechanism, and the actuated clutch pack. By considering several nonlinear factors, such as the slip-stick friction and the contact or not of the clutch plates, the system is piecewise linear. Through the stability analysis of the linearized system in clutch slipping phase, the stable condition of the designed parameters is obtained as α>arctan⁡(μc. The mathematical model of the actuation system is validated by prototype testing. And with the validated model, the system dynamics in both stable and unstable conditions is investigated and discussed in engineering side.

  2. Surface Geophysical Measurements for Locating and Mapping Ice-Wedges

    DEFF Research Database (Denmark)

    Ingeman-Nielsen, Thomas; Tomaskovicova, Sonia; Larsen, S.H.

    2012-01-01

    With the presently observed trend of permafrost warming and degradation, the development and availability of effective tools to locate and map ice-rich soils and massive ground ice is of increasing importance. This paper presents a geophysical study of an area with polygonal landforms in order...... to test the applicability of DC electrical resistivity tomography (ERT) and Ground Penetrating Radar (GPR) to identifying and mapping ice-wedge occurrences. The site is located in Central West Greenland, and the ice-wedges are found in a permafrozen peat soil with an active layer of about 30 cm. ERT...... and GPR measurements give a coherent interpretation of possible ice-wedge locations, and active layer probing show a tendency for larger thaw depth in the major trench systems consistent with a significant temperature (at 10 cm depth) increase in these trenches identified by thermal profiling. Three...

  3. Flow Analysis for the Falkner–Skan Wedge Flow

    DEFF Research Database (Denmark)

    Bararnia, H; Haghparast, N; Miansari, M

    2012-01-01

    In this article an analytical technique, namely the homotopy analysis method (HAM), is applied to solve the momentum and energy equations in the case of a two-dimensional incompressible flow passing over a wedge. The trail and error method and Padé approximation strategies have been used to obtain...... the constant coefficients in the approximated solution. The effects of the polynomial terms of HAM are considered and the accuracy of the results is shown, which increases with the increasing polynomial terms of HAM. Analytical results for the dimensionless velocity and temperature profiles of the wedge flow...

  4. Tool life of ceramic wedges during precise turning of tungsten

    Directory of Open Access Journals (Sweden)

    Legutko Stanislaw

    2017-01-01

    Full Text Available Properties, application and machinability of tungsten and its alloys have been demonstrated. The comparison of the tool life and wear of the wedges made of SiAlON and whisker ceramics during the precise turning at different cutting parameters have been presented. The CNC lathe DMG CTX 310 Ecoline and tungsten of 99.7 % purity were used during the experiments. Only the wedge of whisker ceramics has proved to be sufficiently suitable and only for relatively low cutting speeds.

  5. Severe loin pain following renal biopsy in a high-risk patient: A case report of a rare combination of pseudoaneurysm and arterio-venous fistula

    Directory of Open Access Journals (Sweden)

    Desai Madhav

    2011-01-01

    Full Text Available We report a 50-year-old male patient with diabetes mellitus and hypertension who presented with low-grade fever, anuria and renal failure. He had no prior history of nephropathy and retinopathy. Since anuria persisted, a renal biopsy was performed using automated gun, under ultrasound guidance. Two hours after the renal biopsy was performed, the patient developed severe left loin pain that required analgesics and sedatives. Ultrasound of the abdomen performed immediately, two hours and four hours after the biopsy, did not reveal any hematoma. The hemoglobin was stable when the patient developed loin pain, but after eight hours decreased to 9.1 g/dL, and computed tomography scan of the abdomen revealed a big peri-nephric hematoma around the left kidney. He was managed with blood transfusions and a selective angiogram was done. It revealed a pseudoaneurysm and arterio-venous fistula from the segmental artery of lower pole of the left kidney; both were closed by using microcoils and liquid embolic agent N-butyl-cyanoacrylate (NBCA. The only risk factor the patient had at the time of renal biopsy was severe renal failure. Our case suggests that severe loin pain immediately after renal biopsy in a patient with renal failure warrants careful follow-up of hemoglobin and imaging, even if initial imaging is normal. Further fall of hemoglobin necessitates early evaluation with angiogram, which helps in diagnosing the treatable, although rare, complications like pseudoaneurysm and arterio-venous fistula.

  6. [Duplexsonography investigation in patients with venous ulcer].

    Science.gov (United States)

    Jeanneret-Gris, Christina

    2011-03-01

    Venous hypertension due to venous insufficiency causes venous ulcers. Duplexsonography is a widely accepted non invasive method to assess venous insufficiency with venous reflux measurements. Retrograde venous flow is defined as venous reflux. The testing of venous reflux is reliable if transvalvular pressure is sufficiently high and transvalvular flow velocity exceeds 30 cm/s. Reflux testing in the proximal leg veins (V. femoralis communis, V. femoralis, V. saphena magna) is done using a standardised Valsalva Manoeuvre (exspiration into a tube up to a pressure of 30 mmHg, pressure established within 0.5 seconds, pressure hold for 3 seconds). Distal leg vein testing (V. poplitea, V. tibialis posterior, V. saphena parva) is recommended with a two handed - compression distally to the tested veins. The most important parameter is venous reflux time, a cut off of > 2 seconds is recommended.

  7. Developmental venous anomaly (DVA); Developmental Venous Anomaly (DVA)

    Energy Technology Data Exchange (ETDEWEB)

    Zimmer, A.; Ahlhelm, F.; Viera, J.; Reith, W.; Schulte-Altedorneburg, G. [Universitaetsklinikum des Saarlandes, Klinik fuer Diagnostische und Interventionelle Neuroradiologie, Homburg/Saar (Germany); Hagen, T. [Radiologische Praxis, Augsburg (Germany)

    2007-10-15

    As congenital anatomic variants of venous drainage, developmental venous anomalies (DVA) represent up to 60% of all cerebral vascular malformations. The prior term ''venous angioma'' is a misnomer implicating an abnormal vascular structure with an increased bleeding risk. They are often found incidentally and are hardly ever symptomatic. Their morphologic characteristics are dilated vessels in the white matter, which converge on a greater collector vein, forming the typical caput medusae. They drain into the superficial or deep venous system. The frequent association with other, potentially bleeding-prone vascular malformations is clinically relevant, in particular cavernous angioma, which might require therapeutic action. Therefore, coincident vascular lesions need to be actively sought by appropriate additional imaging techniques. (orig.) [German] Als eine embryologische Variante der venoesen Drainage macht die so genannte ''developmental venous anomaly'' (DVA) etwa 60% aller zerebralen vaskulaeren Malformationen aus. Der vormalige Terminus ''venoeses Angiom'' sollte nicht mehr benutzt werden, da er abnormale Gefaessstrukturen mit einem erhoehten Blutungsrisiko impliziert. Die DVA werden oft inzidentell entdeckt und sind nur selten symptomatisch. Das typische Erscheinungsbild ist durch dilatierte, medusenhauptartig angeordnete venoese Marklagergefaesse gekennzeichnet, die in eine groessere Sammelvene drainieren. Der Abfluss erfolgt ueber das oberflaechliche oder tiefe Venensystem. Klinisch wichtig ist die haeufige Assoziation mit anderen zerebralen Gefaessmalformationen, insbesondere kavernoesen Angiomen, nach denen im Rahmen der Diagnostik explizit gesucht werden muss, da diese eine potenzielle Blutungsquelle darstellen und ein therapeutisches Vorgehen erfordern koennen. (orig.)

  8. Venous chest anatomy: clinical implications

    Energy Technology Data Exchange (ETDEWEB)

    Chasen, M.H.; Charnsangavej, C. [Department of Diagnostic Imaging, The University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States)

    1998-03-01

    This article provides a practical approach to the clinical implications and importance of understanding the collateral venous anatomy of the thorax. Routine radiography, conventional venography, computed tomography (CT), and magnetic resonance (MR) imaging studies provide correlative anatomic models for the demonstration of how interconnecting collateral vascular networks within the thorax maintain venous stability at all times. Five major systems comprise the collateral venous network of the thorax ( Fig. 1 ). These include the paravertebral, azygos-hemiazygos, internal mammary, lateral thoracic, and anterior jugular venous systems (AJVS). The five systems are presented in the following sequence: (a) a brief introduction to the importance of catheter position and malposition in understanding access to the thoracic venous system, (b) the anatomy of the azygos-hemiazygos systems and their relationship with the paravertebral plexus, (c) the importance of the AJVS, (d) 'loop' concepts interconnecting the internal mammary and azygos-hemiazygos systems by means of the lateral thoracic and intercostal veins, and (e) the interconnecting venous networks on the thoracic side of the thoracoabdominal junction. Certain aspects of the venous anatomy of the thorax will not be discussed in this chapter and include (a) the intra-abdominal anastomoses between the superior and inferior vena cavae (IVC) via the internal mammary, lateral thoracic, and azygos-hemiazygos systems (beyond the scope of this article), (b) potential collateral vessels involving vertebral, parascapular, thyroidal, thymic, and other smaller veins that might anastomose with the major systems, and (c) anatomic variants and pitfalls that may mimic pathologic conditions (space limitations). (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  9. Contemporary diagnosis of venous malformation

    Directory of Open Access Journals (Sweden)

    Lee BB

    2013-11-01

    Full Text Available BB Lee,1 I Baumgartner21Department of Surgery, George Washington University, Washington, DC, USA; 2Swiss Cardiovascular Center, University Hospital Bern, Bern, SwitzerlandAbstract: Venous malformation is a congenital vascular malformation resulting from defective development during various stages of embryogenesis and selectively affecting the venous system. Depending on the embryologic stage when the developmental arrest occurred, the clinical presentation of venous malformation is extremely variable in location, extent, severity, natural progression, and hemodynamic impact. Extratruncular lesions occur in the earlier stages of embryonic life, and retain characteristics unique to mesenchymal cells (angioblasts, growing and proliferating when stimulated internally (eg, by menarche, pregnancy, and hormones or externally (eg, by trauma or surgery. These lesions also have a significant hemodynamic impact on the venous system involved, in addition to the risk of localized intravascular coagulopathy. However, truncal lesions, as defective developments along the late stage, no longer carry the risk of proliferation and recurrence due to lack of mesenchymal characteristics. Although, they often have serious hemodynamic consequences due to direct involvement of the main vein trunk. Therefore, a thorough clinical history and careful physical examination should be followed by an appropriate combination of noninvasive and less invasive tests (eg, Doppler ultrasonography, magnetic resonance imaging, computed tomography to confirm the clinical impression as well as to define the extent and severity of the venous malformation. Invasive tests, eg, phlebography or angiography, are seldom needed for the diagnosis per se. Additional evaluation for coagulation abnormalities, eg, D-dimer and fibrinogen levels, is generally recommended, especially for the treatment of surgery and endovascular candidates with extensive lesions to assess the localized intravascular

  10. Computer-assisted detection of pulmonary embolism: evaluation of pulmonary CT angiograms performed in an on-call setting

    Energy Technology Data Exchange (ETDEWEB)

    Wittenberg, Rianne [Academic Medical Centre, Department of Radiology, Amsterdam (Netherlands); University Medical Centre, Department of Radiology, Utrecht (Netherlands); Peters, Joost F.; Sonnemans, Jeroen J. [Philips Healthcare, Healthcare Informatics - Clinical Science and Advanced Development, Best (Netherlands); Prokop, Mathias [University Medical Centre, Department of Radiology, Utrecht (Netherlands); Schaefer-Prokop, Cornelia M. [Academic Medical Centre, Department of Radiology, Amsterdam (Netherlands); Meander Medical Centre, Department of Radiology, Amersfoort (Netherlands)

    2010-04-15

    The purpose of the study was to assess the stand-alone performance of computer-assisted detection (CAD) for evaluation of pulmonary CT angiograms (CTPA) performed in an on-call setting. In this institutional review board-approved study, we retrospectively included 292 consecutive CTPA performed during night shifts and weekends over a period of 16 months. Original reports were compared with a dedicated CAD system for pulmonary emboli (PE). A reference standard for the presence of PE was established using independent evaluation by two readers and consultation of a third experienced radiologist in discordant cases. Original reports had described 225 negative studies and 67 positive studies for PE. CAD found PE in seven patients originally reported as negative but identified by independent evaluation: emboli were located in segmental (n = 2) and subsegmental arteries (n = 5). The negative predictive value (NPV) of the CAD algorithm was 92% (44/48). On average there were 4.7 false positives (FP) per examination (median 2, range 0-42). In 72% of studies {<=}5 FP were found, 13% of studies had {>=}10 FP. CAD identified small emboli originally missed under clinical conditions and found 93% of the isolated subsegmental emboli. On average there were 4.7 FP per examination. (orig.)

  11. Developmental venous anomalies: appearance on whole-brain CT digital subtraction angiography and CT perfusion

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, Eric H. [Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); Touro University Nevada College of Osteopathic Medicine, Henderson, NV (United States); University of Nevada Las Vegas, Department of Health Physics and Diagnostic Sciences, 4505 Maryland Parkway, Box 453037, Las Vegas, NV (United States); Amigenics, Inc, Las Vegas, NV (United States); Roach, Cayce J. [Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); University of Nevada Las Vegas, School of Life Sciences, Las Vegas, NV (United States); Ringdahl, Erik N. [University of Nevada Las Vegas, Department of Psychology, Las Vegas, NV (United States); Wynn, Brad L. [Family Medicine Spokane, Spokane, WA (United States); DeChancie, Sean M.; Mann, Nathan D. [Touro University Nevada College of Osteopathic Medicine, Henderson, NV (United States); Diamond, Alan S. [CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); Orrison, William W. [Touro University Nevada College of Osteopathic Medicine, Henderson, NV (United States); University of Nevada Las Vegas, Department of Health Physics and Diagnostic Sciences, 4505 Maryland Parkway, Box 453037, Las Vegas, NV (United States); CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); University of Nevada School of Medicine, Department of Medical Education, Reno, NV (United States)

    2011-05-15

    Developmental venous anomalies (DVA) consist of dilated intramedullary veins that converge into a large collecting vein. The appearance of these anomalies was evaluated on whole-brain computed tomography (CT) digital subtraction angiography (DSA) and CT perfusion (CTP) studies. CT data sets of ten anonymized patients were retrospectively analyzed. Five patients had evidence of DVA and five age- and sex-matched controls were without known neurovascular abnormalities. CT angiograms, CT arterial-venous views, 4-D CT DSA and CTP maps were acquired on a dynamic volume imaging protocol on a 320-detector row CT scanner. Whole-brain CTP parameters were evaluated for cerebral blood flow (CBF), cerebral blood volume (CBV), time to peak (TTP), mean transit time (MTT), and delay. DSA was utilized to visualize DVA anatomy. Radiation dose was recorded from the scanner console. Increased CTP values were present in the DVA relative to the unaffected contralateral hemisphere of 48%, 32%, and 26%; and for the control group with matched hemispheric comparisons of 2%, -10%, and 9% for CBF, CBV, and MTT, respectively. Average effective radiation dose was 4.4 mSv. Whole-brain DSA and CTP imaging can demonstrate a characteristic appearance of altered DVA hemodynamic parameters and capture the anomalies in superior cortices of the cerebrum and the cerebellum. Future research may identify the rare subsets of patients at increased risk of adverse outcomes secondary to the altered hemodynamics to facilitate tailored imaging surveillance and application of appropriate preventive therapeutic measures. (orig.)

  12. Locally fabricated metal step wedge for quality assurance in ...

    African Journals Online (AJOL)

    radiology department of the Jos University Teaching Hospital (JUTH) using locally acquired metals. The wedges were exposed to x-rays and the optical densities of the processed films measured with a densitometer. The result indicates that standard equipment can be produced from locally sourced materials, as well as to ...

  13. Point focusing with flat and wedged crossed multilayer Laue lenses.

    Science.gov (United States)

    Kubec, Adam; Melzer, Kathleen; Gluch, Jürgen; Niese, Sven; Braun, Stefan; Patommel, Jens; Burghammer, Manfred; Leson, Andreas

    2017-03-01

    Point focusing measurements using pairs of directly bonded crossed multilayer Laue lenses (MLLs) are reported. Several flat and wedged MLLs have been fabricated out of a single deposition and assembled to realise point focusing devices. The wedged lenses have been manufactured by adding a stress layer onto flat lenses. Subsequent bending of the structure changes the relative orientation of the layer interfaces towards the stress-wedged geometry. The characterization at ESRF beamline ID13 at a photon energy of 10.5 keV demonstrated a nearly diffraction-limited focusing to a clean spot of 43 nm × 44 nm without significant side lobes with two wedged crossed MLLs using an illuminated aperture of approximately 17 µm × 17 µm to eliminate aberrations originating from layer placement errors in the full 52.7 µm × 52.7 µm aperture. These MLLs have an average individual diffraction efficiency of 44.5%. Scanning transmission X-ray microscopy measurements with convenient working distances were performed to demonstrate that the lenses are suitable for user experiments. Also discussed are the diffraction and focusing properties of crossed flat lenses made from the same deposition, which have been used as a reference. Here a focal spot size of 28 nm × 33 nm was achieved and significant side lobes were noticed at an illuminated aperture of approximately 23 µm × 23 µm.

  14. Dependence of wedge transmission factor on co-60 teletherapy ...

    African Journals Online (AJOL)

    The equations were validated via linear interpolations by measuring WFs at various treatment depths using Source Axial distance (SAD) and SSD treatment techniques. The approach required only measurements of WF for a 10 x 10 cm2 field at depth of 5 cm employing SSD treatment technique per wedge filter. Using the ...

  15. Fixed Points of Maps of a Nonaspherical Wedge

    Directory of Open Access Journals (Sweden)

    Merrill Keith

    2009-01-01

    Full Text Available Abstract Let be a finite polyhedron that has the homotopy type of the wedge of the projective plane and the circle. With the aid of techniques from combinatorial group theory, we obtain formulas for the Nielsen numbers of the selfmaps of .

  16. Systemic venous drainage: can we help Newton?

    Science.gov (United States)

    Corno, Antonio F

    2007-06-01

    In recent years substantial progress occurred in the techniques of cardiopulmonary bypass, but the factor potentially limiting the flexibility of cardiopulmonary bypass remains the drainage of the systemic venous return. In the daily clinical practice of cardiac surgery, the amount of systemic venous return on cardiopulmonary bypass is directly correlated with the amount of the pump flow. As a consequence, the pump flow is limited by the amount of venous return that the pump is receiving. On cardiopulmonary bypass the amount of venous drainage depends upon the central venous pressure, the height differential between patient and inlet of the venous line into the venous reservoir, and the resistance in the venous cannula(s) and circuit. The factors determining the venous return to be taken into consideration in cardiac surgery are the following: (a) characteristics of the individual patient; (b) type of planned surgical procedure; (c) type of venous cannula(s); (d) type of circuit for cardiopulmonary bypass; (e) strategy of cardiopulmonary bypass; (f) use of accessory mechanical systems to increased the systemic venous return. The careful pre-operative evaluation of all the elements affecting the systemic venous drainage, including the characteristics of the individual patient and the type of required surgical procedure, the choice of the best strategy of cardiopulmonary bypass, and the use of the most advanced materials and tools, can provide a systemic venous drainage substantially better than what it would be allowed by the simple "Law of universal gravitation" by Isaac Newton.

  17. Osteosarcoma of the lumbosacral spine invading the central venous pathways, right-sided cardiac chambers, and pulmonary artery

    Energy Technology Data Exchange (ETDEWEB)

    Hines, Neely; Lantos, George; Hochzstein, Jay [Jacobi Medical Center/Albert Einstein College of Medicine, Department of Radiology, Bronx, NY (United States); Gitig, Alon [Montefiore Medical Center/Albert Einstein College of Medicine, Department of Cardiology, Bronx, NY (United States); DeAnda, Abe [Montefiore Medical Center/Albert Einstein College of Medicine, Department of Cardiothoracic Surgery, Bronx, NY (United States)

    2007-11-15

    We report an unusual case of lumbosacral osteogenic sarcoma with cauda equina syndrome and invasion into the central venous and cardiac system. A 41-year-old Hispanic man presented to the emergency department complaining of severe low back pain, cauda equina syndrome, bilateral lower extremity edema, and an extra heart sound on physical examination. CT of the lumbosacral spine done in the emergency department demonstrated a sclerotic lesion in the sacrum with cortical destruction, extension into the spinal canal and a bulky soft tissue mass containing calcifications. Supplemental MRI demonstrated marrow replacement of L4, L5, and the sacrum, soft tissue extension of the tumor, and invasion iliac veins extending into the IVC; however, the full extent of the intravascular tumor was not seen on this examination. Surgical laminectomy and biopsy of the spinal tumor provided the diagnosis of osteogenic sarcoma. A transthoracic echocardiogram was performed while the patient was recovering due to nonsustained ventricular tachycardia, which showed an echogenic mass within the right atrium and ventricle. CT pulmonary angiogram confirmed the echocardiogram showing a tumor extending through the pulmonary valve into the main pulmonary artery. The patient underwent en bloc resection of the tumor from the venous and cardiac systems. Histologic examination of the tumor confirmed osteogenic sarcoma. While vertebral osteogenic sarcoma is uncommon, invasion of the spinal canal is common in these tumors. However, tumor extending into the central venous and cardiac system is rare. The previously reported cases of central venous and cardiac involvement have been related to distant metastases or primary cardiac osteosarcomas. There is only one other reported case of direct extension into the venous system by an iliac bone osteosarcoma in an adolescent; however, the tumor did not extend into the pulmonary circulation. (orig.)

  18. Cerebral venous thrombosis in childhood

    Energy Technology Data Exchange (ETDEWEB)

    Huisman, T.A.G.M.; Martin, E.; Willi, U.V. [Dept. of Diagnostic Imaging and Radiology, University Children' s Hospital Zurich (Switzerland); Holzmann, D. [Dept. of Otorhinolaryngology, University Children' s Hospital Zurich, Zurich (Switzerland)

    2001-09-01

    This was a retrospective study to determine different etiologies of cerebral venous thrombosis (CVT) in childhood and to correlate extent and location of thrombosis with the etiology and the age of the child as well as the final outcome. In addition, the radiologic approach is discussed. This was a retrospective analysis of 19 children with CVT. The children were examined by contrast-enhanced dynamic CT. Radiologic findings were correlated with the etiology of CVT. Cerebral venous thrombosis is not as infrequent in children as has been thought. Cerebral venous thrombosis in children can occur due to trauma (n=9), infections (n=7), or coagulation disorders (n=3). Extent and location of thrombosis, as well as complications, final outcome, and therapy, depend on the etiology. Computed tomography remains a valuable primary imaging modality in the diagnosis of CVT in the acutely injured or diseased child. (orig.)

  19. The effect of shoe design and lateral wedging on knee loading

    DEFF Research Database (Denmark)

    Mølgaard, Carsten; Kersting, Uwe G.

    wedges were observed in all three types of shoes. However, differences between shoe design were of similar magnitude as the effect of laterally wedged insoles. Only marginal changes in muscle activity for lateral hamstrings during barefoot toe-out walking and gastrocnemius when using the Oxford wedged...

  20. Dutch Venous Ulcer guideline update.

    Science.gov (United States)

    Maessen-Visch, M Birgitte; de Roos, Kees-Peter

    2014-05-01

    The revised guideline of 2013 is an update of the 2005 guideline "venous leg ulcer". In this special project four separate guidelines (venous leg ulcer, varicose veins, compression therapy and deep venous disorders) were revised and developed simultaneously. A meeting was held including representatives of any organisation involved in venous disease management including patient organizations and health insurance companies. Eighteen clinical questions where defined, and a new strategy was used to accelerate the process. This resulted in two new and two revised guidelines within one year. The guideline committee advises use of the C of the CEAP classification as well as the Venous Clinical Severity Score (VCSS) and a Quality of life (QoL) score in the assessment of clinical signs. These can provide insight into the burden of disease and the effects of treatment as experienced by the patient. A duplex ultrasound should be performed in every patient to establish the underlying aetiology and to evaluate the need for treatment (which is discussed in a separate guideline). The use of the TIME model for describing venous ulcers is recommended. There is no evidence for antiseptic or antibiotic wound care products except for a Cochrane review in which some evidence is presented for cadexomer iodine. Signs of infection are the main reason for the use of oral antibiotics. When the ulcer fails to heal the use of oral aspirin and pentoxifylline can be considered as an adjunct. For the individual patient, the following aspects should be considered: the appearance of the ulcer (amount of exudate) according to the TIME model, the influence of wound care products on moisturising the wound, frequency of changing compression bandages, pain and allergies. The cost of the dressings should also be considered. Education and training of patients t improves compliance with compression therapy but does not influence wound healing rates. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  1. A young man with nonhealing venous ulcers

    NARCIS (Netherlands)

    Vloedbeld, M. G.; Venema, A. W.; Smit, A. J.

    A 35-year-old man presented with nonhealing ulcers at an atypical location on his left foot, caused by a combination of venous insufficiency (after deep venous thrombosis) and arterial insufficiency. The underlying cause was Buerger's disease.

  2. Traditional Long-Term Central Venous Catheters Versus Transhepatic Venous Catheters in Infants and Young Children.

    Science.gov (United States)

    Marshall, Amanda Marie; Danford, David A; Curzon, Christopher L; Anderson, Venus; Delaney, Jeffrey W

    2017-10-01

    Children with congenital heart disease may require long-term central venous access for intensive care management; however, central venous access must also be preserved for future surgical and catheterization procedures. Transhepatic venous catheters may be an useful alternative. The objective of this study was to compare transhepatic venous catheters with traditional central venous catheters regarding complication rate and duration of catheter service. Retrospective review of 12 congenital heart disease patients from September 2013 to July 2015 who underwent placement of one or more transhepatic venous catheters. Single freestanding pediatric hospital located in the central United States. Pediatric patients with congenital heart disease who underwent placement of transhepatic venous catheter. Cohort's central venous catheter complication rates and duration of catheter service were compared with transhepatic venous catheter data. Twelve patients had a total of 19 transhepatic venous lines. Transhepatic venous lines had a significantly longer duration of service than central venous lines (p = 0.001). No difference between the two groups was found in the number of documented thrombi, thrombolytic burden, or catheter sites requiring wound care consultation. A higher frequency of infection in transhepatic venous lines versus central venous lines was found, isolated to four transhepatic venous lines that had a total of nine infections. All but one was successfully managed without catheter removal. The difference in the proportion of infections to catheters in transhepatic venous lines versus central venous lines was significant (p = 0.0001), but no difference in the rate of infection-related catheter removal was found. Without compromising future central venous access sites, transhepatic venous lines had superior duration of service without increased thrombosis, thrombolytic use, or insertion site complications relative to central venous lines. Transhepatic venous

  3. Venous leg ulcer in the context of chronic venous disease.

    Science.gov (United States)

    Lozano Sánchez, F S; Marinel lo Roura, J; Carrasco Carrasco, E; González-Porras, J R; Escudero Rodríguez, J R; Sánchez Nevarez, I; Díaz Sánchez, S

    2014-05-01

    Chronic venous disease (CVD) is a frequent disorder with a high socioeconomic impact. Little is known about the possible differences between healed ulcer (C5 group) and active ulcer (C6 group) in terms of disease severity and quality of life (QoL). Our aim was to determine the possible differences in severity disease and QoL between the C5-C6 and C1 (control) group. Data from a national, multicentre, observational and cross-sectional study (n = 1598) were used to compare three groups of CVD: C1 (n = 243), C5 (n = 136) and C6 (n = 70). CVD severity was assessed with the Venous Clinical Severity Score (VCSS) and QoL with the Short Form 12 Health Survey (SF-12) and Chronic Lower Limb Venous Insufficiency Questionnaire (CIVIQ-20). Patients with active ulcers had a higher mean total VCSS than patients with healed ulcers (P ulcers than in those with C1 (P ulcers (C6) had lower QoL scores, but the differences were not statistically significant. Patients with venous leg ulcers (C5-C6) are associated with high severity and poor QoL. However, the healing of a leg ulcer did not contribute to improvement of QoL.

  4. A new sand-wedge-forming mechanism in an extra-arid area

    Science.gov (United States)

    Li, Hongshou; Wang, Wanfu; Wu, Fasi; Zhan, Hongtao; Zhang, Guobing; Qiu, Fei

    2014-04-01

    A survey found that sand wedges are widely distributed in the extremely extra-arid Gobi region of Dunhuang, China. The sand wedges are still developing. Well-developed sand wedges are surrounded by polygonal areas showing fractal structures. The depth of a well-developed sand wedge is 50-60 cm and its maximum width is 50-60 cm, so the depth/width ratio is 1.0. The interface between the wedge and matrix is arc-shaped. The mechanical composition of the sand wedges compared to the matrix is such that 76.72% of the particles have diameters ≤ 0.25 mm and show vertical sand laminations in the sand wedge, while 55.19% of the particles in the matrix are ≥ 2.00 mm in diameter. The particle diameters are consistent with the width of the sand-wedge fractures. The salt content in the sand wedges is 3.13 g/kg, while that of the matrix is 40.86 g/kg. The large salinity difference shows that the sand in the wedges comes from drift sand or cladding layers where salinity is lower, and that the sand wedge was formed in an arid climate. Displacement and pressure are closely associated with the daily temperature variation; they fluctuate significantly following the temperature. Measurements reveal the movement of thermal-contraction fissures. Pressure monitoring identified that wet expansions occurred after rainfall, which made the sand wedges become tightly joined to the matrix. Following this, as the soil became desiccated and shrank, a crack opened in the middle of the sand wedge. This was then filled with drift sand. With the next rainfall, the system moved into another development cycle. The current article reveals a new mechanism for forming sand wedges in extra-arid conditions. Arid sand wedges are a unique drought-induced surface landmark resulting from long-term, natural, dry-climate processes.

  5. Central venous catheters: incidence and predictive factors of venous thrombosis.

    Science.gov (United States)

    Hammes, Mary; Desai, Amishi; Pasupneti, Shravani; Kress, John; Funaki, Brian; Watson, Sydeaka; Herlitz, Jean; Hines, Jane

    2015-07-01

    Central venous catheter access in an acute setting can be a challenge given underlying disease and risk for venous thrombosis. Peripherally inserted central venous catheters (PICCs) are commonly placed but limit sites for fistula creation in patients with chronic renal failure (CKD). The aim of this study is to determine the incidence of venous thrombosis from small bore internal jugular (SBIJ) and PICC line placement. This investigation identifies populations of patients who may not be ideal candidates for a PICC and highlights the importance of peripheral vein preservation in patients with renal failure. A venous Doppler ultrasound was performed at the time of SBIJ insertion and removal to evaluate for thrombosis in the internal jugular vein. Data was collected pre- and post-intervention to ascertain if increased vein preservation knowledge amongst the healthcare team led to less use of PICCs. Demographic factors were collected in the SBIJ and PICC groups and risk factor analysis was completed. 1,122 subjects had PICC placement and 23 had SBIJ placement. The incidence of thrombosis in the PICC group was 10%. One patient with an SBIJ had evidence of central vein thrombosis when the catheter was removed. Univariate and multivariate analysis demonstrated a history of transplant, and the indication of total parenteral nutrition was associated with thrombosis (p<0.001). The decrease in PICCs placed in patients with CKD 6 months before and after intervention was significant (p<0.05). There are subsets of patients ith high risk for thrombosis who may not be ideal candidates for a PICC.

  6. Knowledge Translation of the PERC Rule for Suspected Pulmonary Embolism: A Blueprint for Reducing the Number of CT Pulmonary Angiograms

    Science.gov (United States)

    Drescher, Michael J.; Fried, Jeremy; Brass, Ryan; Medoro, Amanda; Murphy, Timothy; Delgado, João

    2017-01-01

    Introduction Computerized decision support decreases the number of computed tomography pulmonary angiograms (CTPA) for pulmonary embolism (PE) ordered in emergency departments, but it is not always well accepted by emergency physicians. We studied a department-endorsed, evidence-based clinical protocol that included the PE rule-out criteria (PERC) rule, multi-modal education using principles of knowledge translation (KT), and clinical decision support embedded in our order entry system, to decrease the number of unnecessary CTPA ordered. Methods We performed a historically controlled observational before-after study for one year pre- and post-implementation of a departmentally-endorsed protocol. We included patients > 18 in whom providers suspected PE and who did not have a contraindication to CTPA. Providers entered clinical information into a diagnostic pathway via computerized order entry. Prior to protocol implementation, we provided education to ordering providers. The primary outcome measure was the number of CTPA ordered per 1,000 visits one year before vs. after implementation. Results CTPA declined from 1,033 scans for 98,028 annual visits (10.53 per 1,000 patient visits (95% CI [9.9–11.2]) to 892 scans for 101,172 annual visits (8.81 per 1,000 patient visits (95% CI [8.3–9.4]) p<0.001. The absolute reduction in PACT ordered was 1.72 per 1,000 visits (a 16% reduction). Patient characteristics were similar for both periods. Conclusion Knowledge translation clinical decision support using the PERC rule significantly reduced the number of CTPA ordered. PMID:29085542

  7. The Effects of Metabolic Syndrome on Left Main Coronary Artery Stenosis in Coronary Angiograms of Patients: A Two Year Study

    Directory of Open Access Journals (Sweden)

    Panahi A

    2011-12-01

    Full Text Available Background: Left main coronary artery (LMCA stenosis is a leading cause of mortality and morbidity in many countries. Metabolic syndrome (MS is a risk factor for coronary artery disease (CAD. The effects of MS on left main coronary artery stenosis are not well-defined. The aim of this study was to examine the effects of MS on left main coronary artery stenosis.Methods: A total number of 495 patients who underwent elective coronary angiography in the Catheter Laboratory of Cardiovascular in Shariati Hospital 2008-2010 were included in the study. MS definition was based on the National Cholesterol Education Program (NCEP- Adult Treatment Panel III (ATP III criteria. The stenosis in left main coronary arteries was determined by examining the coronary angiograms of the patients.Results: The study population consisted of 249 (50.3% men, and 246 (49.7% women. The mean age of the participants was 58.01±10 years. MS was present in 86 (17.4% of the patients based on NCEP- ATP III criteria. LMCA stenosis was seen in 25 (5% patients. A positive correlation was found between MS and LMCA stenosis (r=0.305, P=0.012. Moreover, a positive correlation was found between age (r=0.192, P=0.05, sex (r=0.334, P=0.007, smoking (r=0.336, P=0.01 and diabetes (r=0.253, P=0.03 and LMCA stenosis.Conclusion: The metabolic syndrome correlates with LMCA stenosis. LMCA stenosis and its correlation with MS is precipitated by high FBG, age, male sex, and smoking which may synergistically increase the risk for the disease.

  8. Triple Rule Out versus CT Angiogram Plus Stress Test for Evaluation of Chest Pain in the Emergency Department

    Directory of Open Access Journals (Sweden)

    Kelly N. Sawyer

    2015-10-01

    Full Text Available Introduction: Undifferentiated chest pain in the emergency department (ED is a diagnostic challenge. One approach includes a dedicated chest computed tomography (CT for pulmonary embolism or dissection followed by a cardiac stress test (TRAD. An alternative strategy is a coronary CT angiogram with concurrent chest CT (Triple Rule Out, TRO. The objective of this study was to describe the ED patient course and short-term safety for these evaluation methods. Methods: This was a retrospective observational study of adult patients presenting to a large, community ED for acute chest pain who had non-diagnostic electrocardiograms (ECGs and normal biomarkers. We collected demographics, ED length of stay, hospital costs, and estimated radiation exposures. We evaluated 30-day return visits for major adverse cardiac events. Results: A total of 829 patients underwent TRAD, and 642 patients had TRO. Patients undergoing TRO tended to be younger (mean 52.3 vs 56.5 years and were more likely to be male (42.4% vs. 30.4%. TRO patients tended to have a shorter ED length of stay (mean 14.45 vs. 21.86 hours, to incur less cost (median $449.83 vs. $1147.70, and to be exposed to less radiation (median 7.18 vs. 16.6mSv. No patient in either group had a related 30-day revisit. Conclusion: Use of TRO is feasible for assessment of chest pain in the ED. Both TRAD and TRO safely evaluated patients. Prospective studies investigating this diagnostic strategy are needed to further assess this approach to ED chest pain evaluation.

  9. Triple Rule Out versus CT Angiogram Plus Stress Test for Evaluation of Chest Pain in the Emergency Department.

    Science.gov (United States)

    Sawyer, Kelly N; Shah, Payal; Qu, Lihua; Kurz, Michael C; Clark, Carol L; Swor, Robert A

    2015-09-01

    Undifferentiated chest pain in the emergency department (ED) is a diagnostic challenge. One approach includes a dedicated chest computed tomography (CT) for pulmonary embolism or dissection followed by a cardiac stress test (TRAD). An alternative strategy is a coronary CT angiogram with concurrent chest CT (Triple Rule Out, TRO). The objective of this study was to describe the ED patient course and short-term safety for these evaluation methods. This was a retrospective observational study of adult patients presenting to a large, community ED for acute chest pain who had non-diagnostic electrocardiograms (ECGs) and normal biomarkers. We collected demographics, ED length of stay, hospital costs, and estimated radiation exposures. We evaluated 30-day return visits for major adverse cardiac events. A total of 829 patients underwent TRAD, and 642 patients had TRO. Patients undergoing TRO tended to be younger (mean 52.3 vs 56.5 years) and were more likely to be male (42.4% vs. 30.4%). TRO patients tended to have a shorter ED length of stay (mean 14.45 vs. 21.86 hours), to incur less cost (median $449.83 vs. $1147.70), and to be exposed to less radiation (median 7.18 vs. 16.6 mSv). No patient in either group had a related 30-day revisit. Use of TRO is feasible for assessment of chest pain in the ED. Both TRAD and TRO safely evaluated patients. Prospective studies investigating this diagnostic strategy are needed to further assess this approach to ED chest pain evaluation.

  10. Experimental investigation of sound absorption of acoustic wedges for anechoic chambers

    Science.gov (United States)

    Belyaev, I. V.; Golubev, A. Yu.; Zverev, A. Ya.; Makashov, S. Yu.; Palchikovskiy, V. V.; Sobolev, A. F.; Chernykh, V. V.

    2015-09-01

    The results of measuring the sound absorption by acoustic wedges, which were performed in AC-3 and AC-11 reverberation chambers at the Central Aerohydrodynamic Institute (TsAGI), are presented. Wedges of different densities manufactured from superfine basaltic and thin mineral fibers were investigated. The results of tests of these wedges were compared to the sound absorption of wedges of the operating AC-2 anechoic facility at TsAGI. It is shown that basaltic-fiber wedges have better sound-absorption characteristics than the investigated analogs and can be recommended for facing anechoic facilities under construction.

  11. Hormonal contraceptives and venous thrombosis

    NARCIS (Netherlands)

    Stegeman, Berendina Hendrika (Bernardine)

    2013-01-01

    Oral contraceptive use is associated with venous thrombosis. However, the mechanism behind this remains unclear. The aim of this thesis was to evaluate genetic variation in the first-pass metabolism of contraceptives, to identify the clinical implications of hormonal contraceptive use after a

  12. Lower-limb venous thrombosis

    African Journals Online (AJOL)

    307. Lower-limb venous thrombosis. July 2009 Vol.27 No.7 CME. Most DVTs arise in calf muscle veins, particularly within the gastrocnemius and soleus muscles (calf vein DVT). Many of these remain localised to the muscle and will not cause any clinical problem. If, however, the circumstances that initially caused the.

  13. The effect of wedge position and inlet geometry on shock wave reflection

    Science.gov (United States)

    Hall, R. E.; da Silva, N. P.; Skews, B. W.; Paton, R. T.

    2017-02-01

    Experiments were conducted in a shock tube to determine the effect of planar wedge inlet geometry on the shock wave reflection pattern that occurred on a wedge. High-speed schlieren imaging was used to visualize the experiments conducted in air with a nominal incident shock strength of Mach 1.31. The experimental test pieces consisted of a wedge mounted above the floor of the shock tube where the underside wedge angle was varied. The upper wedge angle was fixed at 30°, resulting in a Mach reflection. The underside wedge angle was either 30° or 90°, corresponding to a conventional and blunt wedge respectively. For the cases presented here, the reflected shock from the initial interaction reflects off of the shock tube floor and diffracts around the wedge apex. A density gradient is formed at the wedge apex due to this process and results in a vortex being shed for the 90° wedge. It was shown by simple measurements that the diffracted wave could reach the triple point of the upper Mach reflection if the wedge were of sufficient length.

  14. Thoracoscopic pulmonary wedge resection without post-operative chest drain

    DEFF Research Database (Denmark)

    Holbek, Bo Laksafoss; Hansen, Henrik Jessen; Kehlet, Henrik

    2016-01-01

    effusion and coagulopathy. Chest X-rays were done twice on the day of surgery. 30-day complications were compiled from patient records. RESULTS: 49 patients underwent 51 unilateral VATS wedge resections without using a post-operative chest drain. No patient required reinsertion of a chest drain. 30 (59...... %) patients had a pneumothorax of mean size 12 ± 12 mm on supine 8-h post-operative X-ray for which the majority resolved spontaneously within 2-week control. There were no complications on 30-day follow-up. Median length of stay was 1 day. CONCLUSIONS: The results support that VATS wedge resection...... for pulmonary nodules without a post-operative chest drain may be safe in a selected group of patients....

  15. Wedge Diffraction as an Instance of Radiative Shielding

    CERN Document Server

    Grzesik, J A

    2016-01-01

    The celebrated Sommerfeld wedge diffraction solution is reexamined from a null interior field perspective. Exact surface currents provided by that solution, when considered as disembodied half-plane laminae radiating into an ambient, uniform space both inside and outside the wedge proper, do succeed in reconstituting both a specular, mirror field above the exposed face, and a shielding plane-wave field of a sign opposite to that of the incoming excitation which, under superposition, creates both the classical, geometric-optics shadow, and a strictly null interior field at the dominant, plane-wave level. Both mirror and shadow radiated fields are controlled by the residue at just one simple pole encountered during a spectral radiative field assembly, fixed in place by incidence direction $\\phi_{0}$ as measured from the exposed face. The radiated fields further provide diffractive contributions drawn from two saddle points that track observation angle $\\phi.$ Even these, more or less asymptotic contributions, a...

  16. Direct FVM Simulation for Sound Propagation in an Ideal Wedge

    Directory of Open Access Journals (Sweden)

    Hongyu Ji

    2016-01-01

    Full Text Available The sound propagation in a wedge-shaped waveguide with perfectly reflecting boundaries is one of the few range-dependent problems with an analytical solution. This provides a benchmark for the theoretical and computational studies on the simulation of ocean acoustic applications. We present a direct finite volume method (FVM simulation for the ideal wedge problem, and both time and frequency domain results are analyzed. We also study the broadband problem with large-scale parallel simulations. The results presented in this paper validate the accuracy of the numerical techniques and show that the direct FVM simulation could be applied to large-scale complex acoustic applications with a high performance computing platform.

  17. Analysis of Adhesively Bonded Ceramics Using an Asymmetric Wedge Test

    Science.gov (United States)

    2008-12-01

    edges along the lengths of the titanium adherends was cleaned with a small hand-held electric grinding wheel to remove excess adhesive flow. The...energy and bond line durability of titanium bonded to alumina using a structural epoxy film adhesive. This testing scheme limited bending to the more... epoxy adhesive used for the study is estimated to have an initial Gc value ranging from 1000 to 2000 J/m2. A wedge 4 thickness () of 3.18 mm

  18. Wedge Prism for Direction Resolved Speckle Correlation Interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Pechersky, M.J.

    1999-01-20

    The role of a wedge prism for strain sign determination and enhancing the sensitivity for sub-fringe changes is emphasized. The design and incorporation aspects for in-plane sensitive interferometers have been described in detail. Some experimental results dealing with stress determination by laser annealing and speckle corelation interferometry are presented. The prism can also be applied to produce standardized carrier fringes in spatial phase shifting interferometry.

  19. Large scale test of wedge shaped micro strip gas counters

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, M.; Atz, S.; Aulchenko, V.; Bachmann, S.; Baiboussinov, B.; Barthe, S.; Beaumont, W.; Beckers, T.; Beissel, F.; Benhammou, Y.; Bergdolt, A.M.; Bernier, K.; Bluem, P.; Bondar, A.; Bouhali, O.; Boulogne, I.; Bozzo, M.; Brom, J.M.; Camps, C.; Chorowicz, V.; Coffin, J.; Commichau, V.; Contardo, D.; Croix, J.; Troy, J. de; Drouhin, F.; Eberle, H.; Fluegge, G.; Fontaine, J.-C.; Geist, W.; Goerlach, U.; Gundlfinger, K.; Hangarter, K.; Haroutunian, R.; Helleboid, J.M.; Henkes, Th.; Hoffer, M.; Hoffman, C.; Huss, D.; Ischebeck, R.; Jeanneau, F.; Juillot, P.; Junghans, S.; Kapp, M.R.; Kaercher, K.; Knoblauch, D.; Kraeber, M.; Krauth, M.; Kremp, J.; Lounis, A.; Luebelsmeyer, K.; Maazouzi, C.; Macke, D.; Metri, R.; Mirabito, L.; Mueller, Th.; Nagaslaev, V.; Neuberger, D.; Nowack, A.; Pallares, A.; Pandoulas, D.; Petertill, M.; Pooth, O.; Racca, C.; Ripp, I.; Ruoff, E.; Sauer, A.; Schmitz, P.; Schulte, R.; Schultz von Dratzig, A.; Schunk, J.P.; Schuster, G.; Schwaller, B.; Shektman, L.; Siedling, R.; Sigward, M.H.; Simonis, H.J.; Smadja, G.; Stefanescu, J.; Szczesny, H.; Tatarinov, A.; Thuemmel, W.H.; Tissot, S.; Titov, V.; Todorov, T.; Tonutti, M.; Udo, F.; Velde, C. Vander. E-mail: vandervelde@hep.iihe.ac.be; Doninck, W. van; Dyck, Ch. van; Vanlaer, P.; Lancker, L. van; Verdini, P.G.; Weseler, S.; Wittmer, B.; Wortmann, R.; Zghiche, A.; Zhukov, V

    1999-11-01

    In order to check the system aspects of the forward-backward MSGC tracker designed for the future CMS experiment at LHC, 38 trapezoidal MSGC counters assembled in six multi-substrates detector modules were built and exposed to a muon beam at the CERN SPS. Results on the gain uniformity along the wedge-shaped strip pattern and across the detector modules are shown together with measurements of the detection efficiency and the spatial resolution.

  20. Wedges, Wages, and Productivity under the Affordable Care Act

    OpenAIRE

    Casey B. Mulligan; Trevor S. Gallen

    2013-01-01

    Our paper documents the large labor market wedges created by taxes, subsidies, and regulations included in the Affordable Care Act. The law changes terms of trade in both goods and factor markets for firms offering health insurance coverage. We use a multi-sector (intra-national) trade model to predict and quantify consequences of the Affordable Care Act for the patterns of output, labor usage, and employee compensation. We find that the law will significantly redistribute from high-wage work...

  1. Large scale test of wedge shaped micro strip gas counters

    CERN Document Server

    Ackermann, M; Aulchenko, V M; Bachmann, S; Baibusinov, B O; Barthe, S; Beaumont, W; Beckers, T; Beissel, F; Benhammou, Ya; Bergdolt, A M; Bernier, K; Blüm, H P; Bondar, A E; Bouhali, O; Boulogne, I; Bozzo, M; Brom, J M; Camps, C; Chorowicz, V; Coffin, J P; Commichau, V; Contardo, D; Croix, J; De Troy, J G; Drouhin, F; Eberle, H; Flügge, G; Fontaine, J C; Geist, Walter M; Goerlach, U; Gundlfinger, K; Hangarter, K; Haroutunian, R; Helleboid, J M; Henkes, T; Hoffer, M; Hoffmann, C; Huss, D; Ischebeck, R; Jeanneau, F; Juillot, P; Junghans, S; Kapp, M R; Kärcher, K; Knoblauch, D; Kräber, M H; Krauth, M; Kremp, J; Lounis, A; Lübelsmeyer, K; Maazouzi, C; Macke, D; Metri, R; Mirabito, L; Müller, T; Nagaslaev, V; Neuberger, D; Nowak, A; Pallarès, A; Pandoulas, D; Petertill, M; Pooth, O; Racca, C; Ripp, I; Ruoff, E; Sauer, A; Schmitz, P; Schulte, R; Schultz von Dratzig, A; Schunk, J P; Schuster, G; Schwaller, B; Shekhtman, L I; Siedling, R; Sigward, M H; Simonis, H J; Smadja, G; Stefanescu, J; Szczesny, H; Tatarinov, A A; Thümmel, W H; Tissot, S; Titov, V; Todorov, T; Tonutti, M; Udo, Fred; Van der Velde, C; Van Doninck, W K; Van Dyck, C; Vanlaer, P; Van Lancker, L; Verdini, P G; Weseler, S; Wittmer, B; Wortmann, R; Zghiche, A; Zhukov, V

    1999-01-01

    In order to check the system aspects of the forward-backward MSGC tracker designed for the future CMS experiment at LHC, 38 trapezoidal MSGC counters assembled in six multi-substrates detector modules were built and exposed to a muon beam at the CERN SPS. Results on the gain uniformity along the wedge-shaped strip pattern and across the detector modules are shown together with measurements of the detection efficiency and the spatial resolution. (8 refs).

  2. Increased rheumatoid factor and deep venous thrombosis

    DEFF Research Database (Denmark)

    Meyer-Olesen, Christine L; Nielsen, Sune F; Nordestgaard, Børge G

    2015-01-01

    BACKGROUND: The risk of deep venous thrombosis is increased in patients with rheumatoid arthritis. We tested the hypothesis that increased concentrations of rheumatoid factor are associated with increased risk of deep venous thrombosis in individuals without autoimmune rheumatic disease in the ge......BACKGROUND: The risk of deep venous thrombosis is increased in patients with rheumatoid arthritis. We tested the hypothesis that increased concentrations of rheumatoid factor are associated with increased risk of deep venous thrombosis in individuals without autoimmune rheumatic disease...... in the general population. METHODS: We included 54628 participants from the Copenhagen City Heart Study (1981-83) and the Copenhagen General Population Study (2004-12), all with a measured concentration of IgM rheumatoid factor and without autoimmune rheumatic disease or venous thromboembolism. The main outcome...... was incident deep venous thrombosis. There were no losses to follow-up. RESULTS: During 368381 person-years, 670 individuals developed deep venous thrombosis. A rheumatoid factor concentration ≥ vs

  3. On the acoustic wedge design and simulation of anechoic chamber

    Science.gov (United States)

    Jiang, Changyong; Zhang, Shangyu; Huang, Lixi

    2016-10-01

    This study proposes an alternative to the classic wedge design for anechoic chambers, which is the uniform-then-gradient, flat-wall (UGFW) structure. The working mechanisms of the proposed structure and the traditional wedge are analyzed. It is found that their absorption patterns are different. The parameters of both structures are optimized for achieving minimum absorber depth, under the condition of absorbing 99% of normal incident sound energy. It is found that, the UGFW structure achieves a smaller total depth for the cut-off frequencies ranging from 100 Hz to 250 Hz. This paper also proposes a modification for the complex source image (CSI) model for the empirical simulation of anechoic chambers, originally proposed by Bonfiglio et al. [J. Acoust. Soc. Am. 134 (1), 285-291 (2013)]. The modified CSI model considers the non-locally reactive effect of absorbers at oblique incidence, and the improvement is verified by a full, finite-element simulation of a small chamber. With the modified CSI model, the performance of both decorations with the optimized parameters in a large chamber is simulated. The simulation results are analyzed and checked against the tolerance of 1.5 dB deviation from the inverse square law, stipulated in the ISO standard 3745(2003). In terms of the total decoration depth and anechoic chamber performance, the UGFW structure is better than the classic wedge design.

  4. The analysis of terminal endpoint events in stepped wedge designs.

    Science.gov (United States)

    Zhan, Zhuozhao; de Bock, Geertruida H; Wiggers, Theo; van den Heuvel, Edwin

    2016-10-30

    The stepped wedge design is a unique clinical trial design that allows for a sequential introduction of an intervention. However, the statistical analysis is unclear when this design is applied in survival data. The time-dependent introduction of the intervention in combination with terminal endpoints and interval censoring makes the analysis more complicated. In this paper, a time-on-study scale discrete survival model was constructed. Simulations were conducted primarily to study the performance of our model for different settings of the stepped wedge design. Secondary, we compared our approach to continuous Cox proportional hazard model. The results show that the discrete survival model estimates the intervention effects unbiasedly. If the length of the censoring interval is increased, the precision of the estimates is decreased. Without left truncation and late entry, the number of steps improves the precision of the estimates, whereas in combination of left truncation and late entry, the number of steps decreases the precision. Given the same number of participants and clusters, a parallel group design has higher precision than a stepped wedge design. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  5. Radiologically-placed venous ports in children under venous anesthesia

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Joo Yeon; Jeon, Ung Bae; Choo, Ki Seok; Hwang, Jae Yeon; Kim, Yong Woo; Lee, Yun Jin; Nam, Sang Ool; Lim, Young Tak [Pusan National University School of Medicine, Yangsan (Korea, Republic of)

    2015-02-15

    To evaluate the efficacy and safety of radiologic venous port placement in children under venous anesthesia. Between April 2009 and July 2011, 44 ports were implanted in 41 children (24 boys, 17 girls). The age of patients ranged from 9 months to 19 years (mean, 6.5 years) and their body weights ranged from 6.8 kg to 56.3 kg (mean, 23.2 kg). Right internal jugular vein access was used in 42 ports, right subclavian vein in 1, and left subclavian in 1. Durability and complications of port implantation were reviewed. The technical success rate was 100%. The catheter life was 10-661 days (mean 246 days). Two patients died during the follow-up period, 21 and 6 ports were removed at the end of treatment or as a result of complications, respectively. One port was removed and replaced by a Hickmann catheter. Three ports were explanted due to port-related sepsis, one due to a catheter kink, and two for unexplained fever or insertion site pain. The overall port-related infection was 3 cases (6.8%, 0.28/1000 catheter days). Venous port placement by interventional radiologists in children under intravenous sedation is relatively safe, with a high rate of technical success and low rate of complications.

  6. Iliac venous pressure estimates central venous pressure after laparotomy.

    Science.gov (United States)

    Boone, Brian A; Kirk, Katherine A; Tucker, Nikia; Gunn, Scott; Forsythe, Raquel

    2014-09-01

    Central venous pressure (CVP) is traditionally obtained through subclavian or internal jugular central catheters; however, many patients who could benefit from CVP monitoring have only femoral lines. The accuracy of illiac venous pressure (IVP) as a measure of CVP is unknown, particularly following laparotomy. This was a prospective, observational study. Patients who had both internal jugular or subclavian lines and femoral lines already in place were eligible for the study. Pressure measurements were taken from both lines in addition to measurement of bladder pressure, mean arterial pressure, and peak airway pressure. Data were evaluated using paired t-test, Bland-Altman analysis, and linear regression. Measurements were obtained from 40 patients, 26 of which had laparotomy. The mean difference between measurements was 2.2 mm Hg. There were no significant differences between patients who had laparotomy and nonsurgical patients (P = 0.93). Bland-Altman analysis revealed a bias of 1.63 ± 2.44 mm Hg. There was no correlation between IVP accuracy and bladder pressure, mean arterial pressure, or peak airway pressure. IVP is an adequate measure of CVP, even in surgical patients who have had recent laparotomy. Measurement of IVP to guide resuscitation is encouraged in patients who have only femoral venous catheter access. Copyright © 2014. Published by Elsevier Inc.

  7. Chronology and palaeoenvironmental implications of the ice-wedge pseudomorphs and composite-wedge casts on the Magdalen Islands (eastern Canada)

    DEFF Research Database (Denmark)

    Remillard, A.M.; Hetu, B.; Bernatchez, P.

    2015-01-01

    The Magdalen Islands are a valuable terrestrial record, evidencing the complex glacial and periglacial history of the Gulf of St. Lawrence. Thirteen structures interpreted as ice-wedge pseudomorphs or composite-wedge casts were observed at four sites on the southern Magdalen Islands and testify t...

  8. Computerized analysis of coronary artery disease: performance evaluation of segmentation and tracking of coronary arteries in CT angiograms.

    Science.gov (United States)

    Zhou, Chuan; Chan, Heang-Ping; Chughtai, Aamer; Kuriakose, Jean; Agarwal, Prachi; Kazerooni, Ella A; Hadjiiski, Lubomir M; Patel, Smita; Wei, Jun

    2014-08-01

    The authors are developing a computer-aided detection system to assist radiologists in analysis of coronary artery disease in coronary CT angiograms (cCTA). This study evaluated the accuracy of the authors' coronary artery segmentation and tracking method which are the essential steps to define the search space for the detection of atherosclerotic plaques. The heart region in cCTA is segmented and the vascular structures are enhanced using the authors' multiscale coronary artery response (MSCAR) method that performed 3D multiscale filtering and analysis of the eigenvalues of Hessian matrices. Starting from seed points at the origins of the left and right coronary arteries, a 3D rolling balloon region growing (RBG) method that adapts to the local vessel size segmented and tracked each of the coronary arteries and identifies the branches along the tracked vessels. The branches are queued and subsequently tracked until the queue is exhausted. With Institutional Review Board approval, 62 cCTA were collected retrospectively from the authors' patient files. Three experienced cardiothoracic radiologists manually tracked and marked center points of the coronary arteries as reference standard following the 17-segment model that includes clinically significant coronary arteries. Two radiologists visually examined the computer-segmented vessels and marked the mistakenly tracked veins and noisy structures as false positives (FPs). For the 62 cases, the radiologists marked a total of 10191 center points on 865 visible coronary artery segments. The computer-segmented vessels overlapped with 83.6% (8520/10191) of the center points. Relative to the 865 radiologist-marked segments, the sensitivity reached 91.9% (795/865) if a true positive is defined as a computer-segmented vessel that overlapped with at least 10% of the reference center points marked on the segment. When the overlap threshold is increased to 50% and 100%, the sensitivities were 86.2% and 53.4%, respectively. For

  9. A Quantitative and Standardized Method for the Evaluation of Choroidal Neovascularization Using MICRON III Fluorescein Angiograms in Rats.

    Directory of Open Access Journals (Sweden)

    Jonathan P Wigg

    Full Text Available In-vivo imaging of choroidal neovascularization (CNV has been increasingly recognized as a valuable tool in the investigation of age-related macular degeneration (AMD in both clinical and basic research applications. Arguably the most widely utilised model replicating AMD is laser generated CNV by rupture of Bruch's membrane in rodents. Heretofore CNV evaluation via in-vivo imaging techniques has been hamstrung by a lack of appropriate rodent fundus camera and a non-standardised analysis method. The aim of this study was to establish a simple, quantifiable method of fluorescein fundus angiogram (FFA image analysis for CNV lesions.Laser was applied to 32 Brown Norway Rats; FFA images were taken using a rodent specific fundus camera (Micron III, Phoenix Laboratories over 3 weeks and compared to conventional ex-vivo CNV assessment. FFA images acquired with fluorescein administered by intraperitoneal injection and intravenous injection were compared and shown to greatly influence lesion properties. Utilising commonly used software packages, FFA images were assessed for CNV and chorioretinal burns lesion area by manually outlining the maximum border of each lesion and normalising against the optic nerve head. Net fluorescence above background and derived value of area corrected lesion intensity were calculated.CNV lesions of rats treated with anti-VEGF antibody were significantly smaller in normalised lesion area (p < 0.001 and fluorescent intensity (p < 0.001 than the PBS treated control two weeks post laser. The calculated area corrected lesion intensity was significantly smaller (p < 0.001 in anti-VEGF treated animals at 2 and 3 weeks post laser. The results obtained using FFA correlated with, and were confirmed by conventional lesion area measurements from isolectin stained choroidal flatmounts, where lesions of anti-VEGF treated rats were significantly smaller at 2 weeks (p = 0.049 and 3 weeks (p < 0.001 post laser.The presented method of in

  10. Computerized analysis of coronary artery disease: Performance evaluation of segmentation and tracking of coronary arteries in CT angiograms

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Chuan, E-mail: chuan@umich.edu; Chan, Heang-Ping; Chughtai, Aamer; Kuriakose, Jean; Agarwal, Prachi; Kazerooni, Ella A.; Hadjiiski, Lubomir M.; Patel, Smita; Wei, Jun [Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2014-08-15

    Purpose: The authors are developing a computer-aided detection system to assist radiologists in analysis of coronary artery disease in coronary CT angiograms (cCTA). This study evaluated the accuracy of the authors’ coronary artery segmentation and tracking method which are the essential steps to define the search space for the detection of atherosclerotic plaques. Methods: The heart region in cCTA is segmented and the vascular structures are enhanced using the authors’ multiscale coronary artery response (MSCAR) method that performed 3D multiscale filtering and analysis of the eigenvalues of Hessian matrices. Starting from seed points at the origins of the left and right coronary arteries, a 3D rolling balloon region growing (RBG) method that adapts to the local vessel size segmented and tracked each of the coronary arteries and identifies the branches along the tracked vessels. The branches are queued and subsequently tracked until the queue is exhausted. With Institutional Review Board approval, 62 cCTA were collected retrospectively from the authors’ patient files. Three experienced cardiothoracic radiologists manually tracked and marked center points of the coronary arteries as reference standard following the 17-segment model that includes clinically significant coronary arteries. Two radiologists visually examined the computer-segmented vessels and marked the mistakenly tracked veins and noisy structures as false positives (FPs). For the 62 cases, the radiologists marked a total of 10191 center points on 865 visible coronary artery segments. Results: The computer-segmented vessels overlapped with 83.6% (8520/10191) of the center points. Relative to the 865 radiologist-marked segments, the sensitivity reached 91.9% (795/865) if a true positive is defined as a computer-segmented vessel that overlapped with at least 10% of the reference center points marked on the segment. When the overlap threshold is increased to 50% and 100%, the sensitivities were 86

  11. The accuracy of dynamic wedge dose computation in the ADAC Pinnacle RTP system.

    Science.gov (United States)

    Shao, H; Wu, X; Luo, C; Crooks, A; Bernstein, A; Markoe, A

    2004-01-01

    The nonphysical wedge is a modality that uses computer-controlled jaw motion to generate wedge-shaped dose distributions. There are Varian enhanced dynamic wedges (EDWs) and Siemens virtual wedges (VWs). We recently commissioned dynamic wedges on both Varian and Siemens LINACs. The beam data, acquired with a Wellhofer chamber array and a Sun Nuclear profiler, are used for modeling in the ADAC Pinnacle system. As recommended by ADAC, only a limited number of beam data is measured and used for beam modeling. Therefore, the dose distributions of dynamic wedges generated by Pinnacle must be examined. Following the commissioning of the dynamic wedges, we used Pinnacle to generate a number of dose distributions with different energies, wedge angles, field sizes, and depths. The computed data from Pinnacle are then compared with the measured data. The deviations of the output factor in all square and rectangular fields are mostly within 2.0% for both EDW and VW. For asymmetric fields, the deviations are within 3%. However, exceptions of differences more than 3% have been found in a larger field and large wedge combinations. The precision of the beam profiles generated by Pinnacle is also evaluated. As a result of this investigation, we present a scope of quality assurance tests that are necessary to ensure acceptable consistency between the delivered dose and the associated treatment plan when dynamic wedges are applied.

  12. Study of stress distribution of forming slandering of automobile semi-axes with multi-wedge cross wedge rolling by FEM simulation

    Science.gov (United States)

    Zhao, Jing; Shu, Xuedao; Hu, Zhenghuan

    2005-12-01

    Cross wedge rolling with multi-wedge (MCWR) is a new advanced technology of forming the slandering of automobile semi-axes. However, restriction relationship between main wedges and side wedges is complex, there is not almost theory forming automobile axes at inland or overseas. According to the characteristics of forming slandering of automobile semi-axes by MCWR, three-dimensional parameterized model of the MCWR and corresponding program of finite element simulation is worked out. Adopting FEM analysis technology, rules of stress distribution in work piece at main stages, such as knifing zone, stretching zone in main wedges was investigated. The results indicate that forming automobile semi-axes by MCWR is feasible. It provides reliable theory foundation for designing mould of rolling automobile axes by MCWR and choosing technology parameters.

  13. Dose Distribution According to the Tissue Composition Using Wedge Filter by Radiochromic Film

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yon Lae [Dept. of Radiologic Technology, Choonhae College of Health Sciences, Ulsan (Korea, Republic of); Lee, Jeong Woo; Park, Byung Moon [Dept. of Radiation Oncology, Konku University Hospital, Seoul (Korea, Republic of); Jung, Jae Yong; Park, Ji Yeon; Suh, Tae Suk [Dept. of Biomedical Engineering, Catholic University, Seoul (Korea, Republic of)

    2012-06-15

    The purpose of this study is to analyze the dose distribution when wedge filter is used in the various tissue electron density materials. The dose distribution was assessed that the enhanced dynamic wedge filter and physical wedge filter were used in the solid water phantom, cork phantom, and air cavity. The film dosimetry was suitable simple to measure 2D dose distribution. Therefore, the radiochromic films (Gafchromic EBT2, ISP, NJ, USA) were selected to measure and to analyze the dose distributions. A linear accelerator using 6 MV photon were irradiated to field size of 10 x10 cm{sup 2} with 400 MUs. The dose distributions of EBT2 films were analyzed the in-field area and penumbra regions by using dose analysis program. In the dose distributions of wedge field, the dose from a physical wedge was higher than that from a dynamic wedge at the same electron density materials. A dose distributions of wedge type in the solid water phantom and the cork phantom were in agreements with 2%. However, the dose distribution in air cavity showed the large difference with those in the solid water phantom or cork phantom dose distributions. Dose distribution of wedge field in air cavity was not shown the wedge effect. The penumbra width, out of the field of thick and thin, was observed larger from 1 cm to 2 cm at the thick end. The penumbra of physical wedge filter was much larger average 6% than the dynamic wedge filter. If the physical wedge filter is used, the dose was increased to effect the scatter that interacted with photon and physical wedge. In the case of difference in electron like the soft tissue, lung, and air, the transmission, absorption, and scattering were changed in the medium at high energy photon. Therefore, the treatment at the difference electron density should be inhomogeneity correction in treatment planning system.

  14. A regional-scale estimation of ice wedge ice volumes in the Canadian High Arctic

    Science.gov (United States)

    Templeton, M.; Pollard, W. H.; Grand'Maison, C. B.

    2016-12-01

    Ice wedges are both prominent and environmentally vulnerable features in continuous permafrost environments. As the world's Arctic regions begin to warm, concern over the potential effects of ice wedge melt out has become an immediate issue, receiving much attention in the permafrost literature. In this study we estimate the volume of ice wedge ice for large areas in the Canadian High Arctic through the use of high resolution satellite imagery and the improved capabilities of Geographic Information Systems (GIS). The methodology used for this study is similar to that of one performed in Siberia and Alaska by Ulrich et al, in 2014. Utilizing Ulrich's technique, this study detected ice wedge polygons from satellite imagery using ArcGIS. The average width and depth of these ice wedges were obtained from a combination of field data and long-term field studies for the same location. The assumptions used in the analysis of ice wedge volume have been tested, including trough width being representative of ice wedge width, and ice wedge ice content (Pollard and French 1980). This study used specific field sites located near Eureka on Ellesmere Island (N80°01', W85°43') and at Expedition Fiord on Axel Heiberg Island (N79°23', W90°59'). The preliminary results indicate that the methodology used by Ulrich et al, 2014 is transferrable to the Canadian High Arctic, and that ice wedge volumes range between 3-10% of the upper part of permafrost. These findings are similar to previous studies and their importance is made all the more evident by the dynamic nature of ice wedges where it could be argued that they are a key driver of thermokarst terrain. The ubiquitous nature of ice wedges across arctic terrain highlights the importance and the need to improve our understanding of ice wedge dynamics, as subsidence from ice wedge melt-out could lead to large scale landscape change.

  15. [Surgical treatment of chronic venous insufficiency].

    Science.gov (United States)

    Rosales, Antonio; Slagsvold, Carl-Erik; Jørgensen, Jørgen J; Sandbaek, Gunnar

    2009-11-19

    Patients with chronic venous insufficiency (CVI) may develop serious symptoms such as pain, oedema, venous claudication and leg ulcers. Conventional therapy includes compression therapy, elevation of the extremities, and in some cases surgical elimination of superficial varicose veins. This article presents and discusses surgical treatment (reconstructive deep venous surgery and transplantation) and endovascular therapy (percutaneous recanalization of post-thrombotic deep venous occlusions). The article is based on literature identified through non-systematic searches in the PubMed and Cochrane databases. After reconstructive deep venous surgery, ulcer healing is reported in 60-78 % of cases and clinical improvement in 90 %. After such surgery, the median ulcer-free period seems to be longer in primary (congenital, familial), 54 months, than in secondary (after deep vein thrombosis) chronic venous insufficiency (18 months). Recanalization of deep venous occlusions is successful in 90 % of patients who have undergone endovascular treatment of venous claudication and leg ulcer. Reconstructive deep venous surgery constitutes a real treatment choice for patients with chronic venous insufficiency for whom conventional measures have failed. The benefits are ulcer-free periods, clinical improvement, return to work and improved quality of life.

  16. Hyperhomocysteinemia and venous thromboembolic disease.

    Science.gov (United States)

    D'Angelo, A; Mazzola, G; Crippa, L; Fermo, I; Viganò D'Angelo, S

    1997-01-01

    In spite of the large number of reports showing that hyperhomocysteinemia (HHcy) is an independent risk factor for atherosclerosis and arterial occlusive disease, this metabolite of the methionine pathway is measured in relatively few laboratories and its importance is not fully appreciated. Recent data strongly suggest that mild HHcy is also involved in the pathogenesis of venous thromboembolic disease. The aim of this paper is to analyze the most recent advances in this field. The material examined in the present review includes articles and abstracts published in journals covered by the Science Citation Index and Medline. In addition the authors of the present article have been working in the field of mild HHcy as cause of venous thromboembolic disease. The studies examined provide very strong evidence supporting the role of moderate HHcy in the development of premature and/or recurrent venous thromboembolic disease. High plasma homocysteine levels are also a risk factor for deep vein thrombosis in the general population. Folic acid fortification of food has been proposed as a major tool for reducing coronary artery disease mortality in the United States. Vitamin supplementation may also reduce recurrence of venous thromboembolic disease in patients with HHcy. At the present time, however, the clinical efficacy of this approach has not been tested. In addition, the bulk of evidence indicates that fasting total homocysteine determinations can identify up to 50% of the total population of hyperhomocysteinemic subjects. Patients with isolated methionine intolerance may benefit from vitamin B6 supplementation. Homocysteine-lowering vascular disease prevention trials are urgently needed. Such controlled studies, however, should not focus exclusively on fasting homocysteine determinations and folic acid monotherapy.

  17. Standard Care vs Corticosteroid for Retinal Vein Occlusion (SCORE) Study system for evaluation of stereoscopic color fundus photographs and fluorescein angiograms: SCORE Study Report 9.

    Science.gov (United States)

    Blodi, Barbara A; Domalpally, Amitha; Scott, Ingrid U; Ip, Michael S; Oden, Neal L; Elledge, Julee; Warren, Kelly; Altaweel, Michael M; Kim, Judy E; Van Veldhuisen, Paul C

    2010-09-01

    To describe the procedures and reproducibility for grading stereoscopic color fundus photographs and fluorescein angiograms of participants in the SCORE Study. Standardized stereoscopic fundus photographs and fluorescein angiograms taken at 84 clinical centers were evaluated by graders at a central reading center. Type of retinal vein occlusion (RVO), area of retinal thickening, and area of retinal hemorrhage are evaluated from fundus photographs; area of fluorescein leakage and area of capillary nonperfusion are measured on fluorescein angiography. Temporal reproducibility consisted of annual regrading of a randomly selected dedicated subset of fundus photographs (60 subjects) and fluorescein angiograms (40 subjects) for 3 successive years. Contemporaneous reproducibility involved monthly regrading of a 5% random selection of recently evaluated fundus photographs (n = 73). The intergrader agreement for RVO type and presence of retinal thickening was greater than 90% in the 3 annual regrades. The intraclass correlation (ICC) for area of retinal thickening in the 3 years ranged from 0.39 to 0.64 and for area of retinal hemorrhage, 0.87 to 0.96. The ICC for area of fluorescein leakage ranged from 0.66 to 0.75 and for capillary nonperfusion, 0.94 to 0.97. The contemporaneous reproducibility results were similar to those of temporal reproducibility for all variables except area of retinal thickening (ICC, 0.84). The fundus photography and fluorescein angiography grading procedures for the SCORE Study are reproducible and can be used for multicenter longitudinal studies of RVO. A systematic temporal drift occurred in evaluating area of retinal thickening.

  18. Venous drainage of the face.

    Science.gov (United States)

    Onishi, S; Imanishi, N; Yoshimura, Y; Inoue, Y; Sakamoto, Y; Chang, H; Okumoto, T

    2017-04-01

    The venous anatomy of the face was examined in 12 fresh cadavers. Venograms and arteriovenograms were obtained after the injection of contrast medium. In 8 of the 12 cadavers, a large loop was formed by the facial vein, the supratrochlear vein, and the superficial temporal vein, which became the main trunk vein of the face. In 4 of the 12 cadavers, the superior lateral limb of the loop vein was less well developed. The loop vein generally did not accompany the arteries of the face. Cutaneous branches of the loop vein formed a polygonal venous network in the skin, while communicating branches ran toward deep veins. These findings suggest that blood from the dermis of the face is collected by the polygonal venous network and enters the loop vein through the cutaneous branches, after which blood flows away from the face through the superficial temporal vein, the facial vein, and the communicating branches and enters the deep veins. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  19. Degradation and stabilization of ice wedges: Implications for assessing risk of thermokarst in northern Alaska

    Science.gov (United States)

    Kanevskiy, Mikhail; Shur, Yuri; Jorgenson, Torre; Brown, Dana R. N.; Moskalenko, Nataliya; Brown, Jerry; Walker, Donald A.; Raynolds, Martha K.; Buchhorn, Marcel

    2017-11-01

    Widespread degradation of ice wedges has been observed during the last decades in numerous areas within the continuous permafrost zone of Eurasia and North America. To study ice-wedge degradation, we performed field investigations at Prudhoe Bay and Barrow in northern Alaska during 2011-2016. In each study area, a 250-m transect was established with plots representing different stages of ice-wedge degradation/stabilization. Field work included surveying ground- and water-surface elevations, thaw-depth measurements, permafrost coring, vegetation sampling, and ground-based LiDAR scanning. We described cryostratigraphy of frozen soils and stable isotope composition, analyzed environmental characteristics associated with ice-wedge degradation and stabilization, evaluated the vulnerability and resilience of ice wedges to climate change and disturbances, and developed new conceptual models of ice-wedge dynamics that identify the main factors affecting ice-wedge degradation and stabilization and the main stages of this quasi-cyclic process. We found significant differences in the patterns of ice-wedge degradation and stabilization between the two areas, and the patterns were more complex than those previously described because of the interactions of changing topography, water redistribution, and vegetation/soil responses that can interrupt or reinforce degradation. Degradation of ice wedges is usually triggered by an increase in the active-layer thickness during exceptionally warm and wet summers or as a result of flooding or disturbance. Vulnerability of ice wedges to thermokarst is controlled by the thickness of the intermediate layer of the upper permafrost, which overlies ice wedges and protects them from thawing. In the continuous permafrost zone, degradation of ice wedges rarely leads to their complete melting; and in most cases wedges eventually stabilize and can then resume growing, indicating a somewhat cyclic and reversible process. Stabilization of ice wedges

  20. Dosimetric Characteristics of 6 MV Modified Beams by Physical Wedges of a Siemens Linear Accelerator.

    Science.gov (United States)

    Zabihzadeh, Mansour; Birgani, Mohammad Javad Tahmasebi; Hoseini-Ghahfarokhi, Mojtaba; Arvandi, Sholeh; Hoseini, Seyed Mohammad; Fadaei, Mahbube

    2016-01-01

    Physical wedges still can be used as missing tissue compensators or filters to alter the shape of isodose curves in a target volume to reach an optimal radiotherapy plan without creating a hotspot. The aim of this study was to investigate the dosimetric properties of physical wedges filters such as off-axis photon fluence, photon spectrum, output factor and half value layer. The photon beam quality of a 6 MV Primus Siemens modified by 150 and 450 physical wedges was studied with BEAMnrc Monte Carlo (MC) code. The calculated present depth dose and dose profile curves for open and wedged photon beam were in good agreement with the measurements. Increase of wedge angle increased the beam hardening and this effect was more pronounced at the heal region. Using such an accurate MC model to determine of wedge factors and implementation of it as a calculation algorithm in the future treatment planning systems is recommended.

  1. Starling curves and central venous pressure

    OpenAIRE

    Berlin, Cheryl; Bakker, Jan

    2014-01-01

    textabstractRecent studies challenge the utility of central venous pressure monitoring as a surrogate for cardiac preload. Starting with Starling’s original studies on the regulation of cardiac output, this review traces the history of the experiments that elucidated the role of central venous pressure in circulatory physiology. Central venous pressure is an important physiologic parameter, but it is not an independent variable that determines cardiac output.

  2. Calf venous compliance measured by venous occlusion plethysmography: methodological aspects.

    Science.gov (United States)

    Skoog, Johan; Zachrisson, Helene; Lindenberger, Marcus; Ekman, Mikael; Ewerman, Lea; Länne, Toste

    2015-02-01

    Calf venous compliance (C calf) is commonly evaluated with venous occlusion plethysmography (VOP) during a standard cuff deflation protocol. However, the technique relies on two not previously validated assumptions concerning thigh cuff pressure (P cuff) transmission and the impact of net fluid filtration (F filt) on C calf. The aim was to validate VOP in the lower limb and to develop a model to correct for F filt during VOP. Strain-gauge technique was used to study calf volume changes in 15 women and 10 age-matched men. A thigh cuff was inflated to 60 mmHg for 4 and 8 min with a subsequent decrease of 1 mmHg s(-1). Intravenous pressure (P iv) was measured simultaneously. C calf was determined with the commonly used equation [Compliance = β 1 + 2β 2 × P cuff] describing the pressure-compliance relationship. A model was developed to identify and correct for F filt. Transmission of P cuff to P iv was 100 %. The decrease in P cuff correlated well with P iv reduction (r = 0.99, P < 0.001). Overall, our model showed that C calf was underestimated when F filt was not accounted for (all P < 0.01). F filt was higher in women (P < 0.01) and showed a more pronounced effect on C calf compared to men (P < 0.05). The impact of F filt was similar during 4- and 8-min VOP. P cuff is an adequate substitute for P iv in the lower limb. F filt is associated with an underestimation of C calf and differences in the effect of F filt during VOP can be accounted for with the correction model. Thus, our model seems to be a valuable tool in future studies of venous wall function.

  3. Ice-wedge based permafrost chronologies and stable-water isotope records from Arctic Siberia

    OpenAIRE

    Wetterich, Sebastian; Opel, Thomas; Meyer, Hanno; Schwamborn, Georg; Schirrmeister, Lutz; Derevyagin, Alexander Yu

    2016-01-01

    Late Quaternary permafrost of northern latitudes contains large proportions of ground ice, including pore ice, segregation ice, massive ice, buried glacier ice and in particular ice wedges. Fossil ice-wedges are remnants of polygonal patterned ground in former tundra areas, which evolved over several tens of thousands of years in non-glaciated Beringia. Ice wedges originate from repeated frost cracking of the ground in winter and subsequent crack filling by snowmelt and re-freezing in the gro...

  4. Pan-Arctic ice-wedge degradation in warming permafrost and its influence on tundra hydrology

    OpenAIRE

    Liljedahl, Anna K.; Boike, Julia; Daanen, Ronald P.; Fedorov, Alexander N.; Frost, Gerald V.; Grosse, Guido; Hinzman, Larry D.; Iijma, Yoshihiro; Jorgenson, Janet C.; Matveyeva, Nadya; Necsoiu, Marius; Raynolds, Martha K.; Romanovsky, Vladimir E.; Schulla, Jörg; Tape, Ken D.

    2016-01-01

    Ice wedges are common features of the subsurface in permafrost regions. They develop by repeated frost cracking and ice vein growth over hundreds to thousands of years. Ice-wedge formation causes the archetypal polygonal patterns seen in tundra across the Arctic landscape. Here we use field and remote sensing observations to document polygon succession due to ice-wedge degradation and trough development in ten Arctic localities over sub-decadal timescales. Initial thaw drains polygon centres ...

  5. Wedge factor constituents of high-energy photon beams: head and phantom scatter dose components.

    Science.gov (United States)

    Heukelom, S; Lanson, J H; Mijnheer, B J

    1994-07-01

    The head and phantom scatter contribution to the output of a treatment machine have been determined for open and wedged 60Co gamma-ray beams and 4, 8, 16 and 25 MV X-ray beams, using an extended and a small-sized phantom. The wedge factor variation with field size and phantom depth have been analysed as a function of both scatter components. For the wedged beams a stronger increase of the head scatter contribution with field size, i.e. 4-9% for field sizes increasing from 5 cm x 5 cm to 20 cm x 20 cm, has been observed compared with open beams. This result indicates that the wedge factor variation with field size is related to a change of the primary photon fluence. Our study shows that the ratio of the head and phantom scatter contribution for the wedged and open beams remains unchanged for all beams except the 4 and 25 MV X-ray beam. This implies that, except for these latter energies, the variation of the wedge factor with phantom depth is determined by the wedge-induced change of the primary photon energy fluence. For the 4 and 25 MV X-ray beam it is shown that the wedge factor is also influenced by a change of the phantom scatter contribution. The wedge factor for the 25 MV X-ray beam is strongly influenced by the electron contamination for phantom depths up to 6 cm. For the 60Co and the 4 MV photon beam it is shown that the wedge factor decreases slightly with increasing source-to-skin distance due to a reduced contribution to the total dose from photons scattered in the wedge. For clinical use, an algorithm is given to calculate the wedge factor variation with field size and phantom depth.

  6. Development and growth of structural wedges in northwest Qaidam basin, China

    Science.gov (United States)

    Sun, Y.; Shaw, J. H.; Guan, S.; Ma, D.

    2016-12-01

    Structural wedges contain two connected fault segments, a fore-thrust and back-thrust, that bound a triangular or wedge shaped fault block. We document a series of natural structural wedges in northwest Qaidam basin, China, where syntectonic strata record deformation timing and kinematics. The Qaidam basin is located at the northern margin of the Tibetan Plateau and developed more than one hundred anticlinal structures, many of which exhibit characteristics of structural wedges. Based on fault related fold theory, we interpret and model these structures using subsurface seismic reflection data, surface geological exposures, remote sensing and digital elevation data. The structures in northwest Qaidam basin typically include a southwest dipping thrust fault, constituting the back-thrust of the wedge system. Fault-bend and propagation folds develop in the hanging walls of these faults. At depth, these back-thrusts are rooted into northeast dipping fore-thrusts forming structural wedges. These wedge structures are distinguished by having elevated strata in the footwalls of the back-thrusts, and synclinal folds that extend upward from the wedge tips. Deformation timing and kinematics of the structural wedges are constrained by syntectonic (growth) strata. With these constraints, we forward model several of these structures (Dafengshan, Changweiliang, Heiliangzi, Jiandingshan, and Jianbei ) using MOVE software. These forward models help to characterize the location and geometry of the deeper faults, many of which are tectonically active. The forward modelling process indicates that some of the wedges include imbricated back-thrusts. Moreover, all of the systems exhibit significant variations along strike. We apply palinspastic and map-based restoration methods to establish that several of these wedge structures are part of a linked system, where along-strike changes in geometry reflect slip transfer from one wedge system to another.

  7. Understanding Flow and Transport in Ice Wedge Polygons Using Tracers

    Science.gov (United States)

    Wales, N. A.; Newman, B. D.; Wilson, C. J.; Gomez-Velez, J. D.

    2016-12-01

    Ice wedge polygons are among the most prevalent landforms in lowland Arctic landscapes and are associated with high concentrations of permafrost carbon. The fate of this carbon in a warming climate is dependent on the rate of ice wedge degradation and its influence on hydrology. Most regional and pan-arctic land models focus on the representation of vertical water fluxes in the form of infiltration and evapotranspiration. Our work aims to better quantify the relative roles of vertical and subsurface horizontal water fluxes in these landscapes, providing data to revise, test, and calibrate permafrost hydrology representations in these models. We examined the controls of frost table depth, microtopography, and soil type on subsurface flow and transport within both a low centered polygon (LCP) and a high centered polygon (HCP) to better understand how topographic inversion due to ice wedge degradation will impact subsurface horizontal flow. A bromide solution was applied at both polygons in July of 2015. Macrorhizon samplers placed at various depths in the polygon centers, rims, and troughs were used to monitor tracer concentrations. Water level data and frost table depth measurements were also taken throughout the experiment. Tracer movement has been relatively slow, taking most of the first field season to arrive at a subsurface sampler, also called "breakthrough". Tracer travel times from polygon centers to rims and from surface to the frost table were shorter in the LCP than in the HCP. Preferential flow paths, influenced by topography and frost table depth, were found exist between polygon centers and troughs. Preliminary data also suggests that water typically flows downward to the frost table and then laterally. Correlations between tracer arrival time and absolute thaw depth are assessed, along with the relationships between tracer breakthough curves and polygon types and features.

  8. Modes of continental extension in a crustal wedge

    KAUST Repository

    Wu, Guangliang

    2015-07-01

    © 2015 Elsevier B.V. We ran numerical experiments of the extension of a crustal wedge as an approximation to extension in an orogenic belt or a continental margin. We study the effects of the strength of the lower crust and of a weak mid-crustal shear zone on the resulting extension styles. A weak mid-crustal shear zone effectively decouples upper crustal extension from lower crustal flow. Without the mid-crustal shear zone, the degree of coupling between the upper and the lower crust increases and extension of the whole crust tends to focus on the thickest part of the wedge. We identify three distinct modes of extension determined by the strength of the lower crust, which are characterized by 1) localized, asymmetric crustal exhumation in a single massif when the lower crust is weak, 2) the formation of rolling-hinge normal faults and the exhumation of lower crust in multiple core complexes with an intermediate strength lower crust, and 3) distributed domino faulting over the weak mid-crustal shear zone when the lower crust is strong. A frictionally stronger mid-crustal shear zone does not change the overall model behaviors but extension occurred over multiple rolling-hinges. The 3 modes of extension share characteristics similar to geological models proposed to explain the formation of metamorphic core complexes: 1) the crustal flow model for the weak lower crust, 2) the rolling-hinge and crustal flow models when the lower crust is intermediate and 3) the flexural uplift model when the lower crust is strong. Finally we show that the intensity of decoupling between the far field extension and lower crustal flow driven by the regional pressure gradient in the wedge control the overall style of extension in the models.

  9. Thermodynamic and kinetic supercooling of liquid in a wedge pore.

    Science.gov (United States)

    Nowak, Dominika; Heuberger, Manfred; Zäch, Michael; Christenson, Hugo K

    2008-10-21

    Cyclohexane allowed to capillary condense from vapor in an annular wedge pore of mica in a surface force apparatus (SFA) remains liquid down to at least 14 K below the bulk melting-point T(m). This is an example of supercooling of a liquid due to confinement, like melting-point depression in porous media. In the wedge pore, however, the supercooled liquid is in equilibrium with vapor, and the amount of liquid (and thereby the radius of curvature r of the liquid-vapor interface) depends on the surface tension gamma(LV) of the liquid, not the interfacial tension between the solid and liquid. At coexistence r is inversely proportional to the temperature depression DeltaT below T(m), in accordance with a recently proposed model [P. Barber, T. Asakawa, and H. K. Christenson, J. Phys. Chem. C 111, 2141 (2007)]. We have now extended this model to include effects due to the temperature dependence of both the surface tension and the enthalpy of melting. The predictions of the improved model have been quantitatively verified in experiments using both a Mark IV SFA and an extended surface force apparatus (eSFA). The three-layer interferometer formed by the two opposing, backsilvered mica surfaces in a SFA was analyzed by conventional means (Mark IV) and by fast spectral correlation of up to 40 fringes (eSFA). We discuss the absence of freezing in the outermost region of the wedge pore down to 14 K below T(m) and attribute it to nonequilibrium (kinetic) supercooling, whereas the inner region of the condensate is thermodynamically supercooled.

  10. Thermodynamic and kinetic supercooling of liquid in a wedge pore

    Science.gov (United States)

    Nowak, Dominika; Heuberger, Manfred; Zäch, Michael; Christenson, Hugo K.

    2008-10-01

    Cyclohexane allowed to capillary condense from vapor in an annular wedge pore of mica in a surface force apparatus (SFA) remains liquid down to at least 14K below the bulk melting-point Tm. This is an example of supercooling of a liquid due to confinement, like melting-point depression in porous media. In the wedge pore, however, the supercooled liquid is in equilibrium with vapor, and the amount of liquid (and thereby the radius of curvature r of the liquid-vapor interface) depends on the surface tension γLV of the liquid, not the interfacial tension between the solid and liquid. At coexistence r is inversely proportional to the temperature depression ΔT below Tm, in accordance with a recently proposed model [P. Barber, T. Asakawa, and H. K. Christenson, J. Phys. Chem. C 111, 2141 (2007)]. We have now extended this model to include effects due to the temperature dependence of both the surface tension and the enthalpy of melting. The predictions of the improved model have been quantitatively verified in experiments using both a Mark IV SFA and an extended surface force apparatus (eSFA). The three-layer interferometer formed by the two opposing, backsilvered mica surfaces in a SFA was analyzed by conventional means (Mark IV) and by fast spectral correlation of up to 40 fringes (eSFA). We discuss the absence of freezing in the outermost region of the wedge pore down to 14K below Tm and attribute it to nonequilibrium (kinetic) supercooling, whereas the inner region of the condensate is thermodynamically supercooled.

  11. Central venous line complications and tip detection

    Directory of Open Access Journals (Sweden)

    Ameneh Rezaee Gheshlaghi

    2015-06-01

    Full Text Available Central venous line is one of a creative instrument that saves human’s life in critical medical situation. Central venous line access is frequently involved in the disease management. It is used for rapid fluid therapy, transvenous pacemakers, infusion of some medications, hemodialysis or plasmapheresis and etc. Most of the emergency departments have some staffs that are trained for central venous line insertion but related complications occur during central venous line placement.Central venous line might have some complications and complication follow-up should be considered. Thromboembolism and infection are two important medical complications. Arterial puncture, hematoma, pneumothorax and hemothorax are mechanical Central venous line complications. Chest X-ray and some other techniques should be used for detecting these complications.Central venous line tip misplace is a considerable problem for emergency department staffs, previously chest X-ray has been used for central venous line misplace detection. In some recent studies, contrast-enhanced ultrasonography and intravascular electrocardiography have been used for central venous line misplace.

  12. Interpretation and inverse analysis of the wedge splitting test

    DEFF Research Database (Denmark)

    Østergaard, Lennart; Stang, Henrik

    2002-01-01

    Determination of the stress-crack opening relationship, s(w) a material parameter in the fictitious crack model by Hillerborg has proven to be problematic and is still not a simple task to perform. However, this paper demonstrates that the cracked non-linear hinge model by Olesen may be applied...... to the wedge splitting test and that it is well suited for the interpretation of test results in terms of s(w). A fine agreement between the hinge and FEM-models has been found. It has also been found that the test and the hinge model form a solid basis for inverse analysis. The paper also discusses possible...

  13. Heat conduction problem of an evaporating liquid wedge

    Directory of Open Access Journals (Sweden)

    Tomas Barta

    2015-02-01

    Full Text Available We consider the stationary heat transfer near the contact line of an evaporating liquid wedge surrounded by the atmosphere of its pure vapor. In a simplified setting, the problem reduces to the Laplace equation in a half circle, subject to a non-homogeneous and singular boundary condition. By classical tools (conformal mapping, Green's function, we reformulate the problem as an integral equation for the unknown Neumann boundary condition in the setting of appropriate fractional Sobolev and weighted space. The unique solvability is then obtained by means of the Fredholm theorem.

  14. Magmatism significantly alters the thermal structure of the wedge

    Science.gov (United States)

    Rees Jones, D. W.; Katz, R. F.; Rudge, J. F.; Tian, M.

    2016-12-01

    The temperature structure of the mantle wedge is typically modelled as a balance between thermal diffusion and advection by the solid mantle [e.g., 1]. The thermal state of the wedge promotes melting and melt transport in the natural system, but the thermal consequences of these processes have been neglected from previous models. We show that advective transport of sensible and latent heat by liquid magma can locally alter the temperature structure from canonical models by up to 200K. Liquids are liberated from the subducting slab by de-volatilization reactions. They trigger melting and become silicic en route to the surface, where they cause arc volcanism. These liquids transport heat advectively, and consume or supply latent heat as they melt or freeze. To analyse these effects, we parameterise melting in the presence of volatile species. We combine this with a one-dimensional "melting-column model," previously used to understand mid-ocean ridge volcanism. Our calculations highlight the thermal and chemical response to melt transport across the mantle wedge. Finally, we solve two-dimensional geodynamic models with a prescribed slab flux [2]. These models allow us to identify the most thermally significant fluxes of melt in the system. Perturbations of 200K are found at the base of the overriding lithosphere. This thermal signature of melt migration should be considered when interpreting heat flow, petrologic and seismic data [e.g., 3]. Such a thermal perturbation is likely to affect the chemistry of arc volcanoes, the solid mantle flow and, perhaps, the location of the volcanos themselves [4]. [1] van Keken, P. E., Currie, C., King, S. D., Behn, M. D., Cagnioncle, A., He, J., et al. (2008). A community benchmark for subduction zone modeling. PEPI, doi:10.1016/j.pepi.2008.04.015 [2] Wilson, C. R., Spiegelman, M., van Keken, P. E., & Hacker, B. R. (2014). Fluid flow in subduction zones: The role of solid rheology and compaction pressure. EPSL, doi:10.1016/j

  15. Decollement controls on pro versus retro wedge deformation in mountain belts

    Science.gov (United States)

    Grool, Arjan; Huismans, Ritske S.; Ford, Mary

    2017-04-01

    Doubly vergent orogens have a pro-wedge (lower plate) and a retro-wedge (upper plate). Most shortening is accommodated on the pro-wedge while retro-wedge shortening is typically limited. For example, the Eastern Pyrenees have experienced about 145 km of convergence, of which about 125 km (86%) was accommodated in the pro-wedge and about 20 km (14%) in the retro-wedge. Strain partitioning between pro- and retro-wedge is influenced by several factors, some of which have been identified in past work: Extensional inheritance and syn-orogenic sedimentation can help to increase the percentage of total shortening accommodated in the retro-wedge while erosion promotes pro-wedge shortening. We use high-resolution 2D numerical models to investigate factors that control pro- versus retro-wedge shortening. For a total convergence similar to the Eastern Pyrenees, our models predict that variations in extensional inheritance and syn-orogenic sedimentation will result in a maximum of 10% of total shortening being accommodated in the retro-wedge. Here, we investigate the role of 1) the rheology and 2) distribution of a decollement layer. Our models show that: 1) Decollement rheology has a first order control on strain distribution between the pro- and the retro-wedge. After 145 km of total convergence, a model with a weak frictional (φ=2, shale-like) decollement will only accommodate 9% of total shortening in the retro-wedge. In contrast in models with a weak viscous (μ=1018, salt-like) decollement retro-wedge shortening amounts to 18% and a stronger, but still weak, viscous decollement (μ=1019) leads to 21%. 2) Décollement distribution influences the timing of the first outward propagation of thick-skinned deformation in the retro-wedge. In the Eastern Pyrenees, thick-skinned deformation propagated out into the retro-wedge within 145 km of total convergence. In models with a decollement on both sides of the orogen this only occurred after 240 km. If, as in the Eastern

  16. Reconstruction of Intima and Adventitia Models into a State Undeformed by a Catheter by Using CT, IVUS, and Biplane X-Ray Angiogram Images

    Directory of Open Access Journals (Sweden)

    Jinwon Son

    2017-01-01

    Full Text Available The number of studies on blood flow analysis using fluid-structure interaction (FSI analysis is increasing. Though a 3D blood vessel model that includes intima and adventitia is required for FSI analysis, there are difficulties in generating it using only one type of medical imaging. In this paper, we propose a 3D modeling method for accurate FSI analysis. An intravascular ultrasound (IVUS image is used with biplane X-ray angiogram images to calculate the position and orientation of the blood vessel. However, these images show that the blood vessel is deformed by the catheter inserted into the blood vessel for IVUS imaging. To eliminate such deformation, a CT image was added and the two models were registered. First, a 3D model of the undeformed intima was generated using a CT image. In the second stage, a model of intima and adventitia deformed by the catheter was generated by combining the IVUS image and the X-ray angiogram images. A 3D model of intima and adventitia with the deformation caused by insertion of the catheter eliminated was generated by matching these 3D blood vessel models in different states. In addition, a 3D blood vessel model including bifurcation was generated using the proposed method.

  17. Effects of altering heel wedge properties on gait with the Intrepid Dynamic Exoskeletal Orthosis.

    Science.gov (United States)

    Ikeda, Andrea J; Fergason, John R; Wilken, Jason M

    2017-09-01

    The Intrepid Dynamic Exoskeletal Orthosis is a custom-made dynamic response carbon fiber device. A heel wedge, which sits in the shoe, is an integral part of the orthosis-heel wedge-shoe system. Because the device restricts ankle movement, the system must compensate to simulate plantarflexion and allow smooth forward progression during gait. To determine the influence of wedge height and durometer on the walking gait of individuals using the Intrepid Dynamic Exoskeletal Orthosis. Repeated measures. Twelve individuals walked over level ground with their Intrepid Dynamic Exoskeletal Orthosis and six different heel wedges of soft or firm durometer and 1, 2, or 3 cm height. Center of pressure velocity, joint moments, and roll-over shape were calculated for each wedge. Height and durometer significantly affected time to peak center of pressure velocity, time to peak internal dorsiflexion and knee extension moments, time to ankle moment zero crossing, and roll-over shape center of curvature anterior-posterior position. Wedge height had a significant influence on peak center of pressure velocity, peak dorsiflexion moment, time to peak knee extension moment, and roll-over shape radius and vertical center of curvature. Changes in wedge height and durometer systematically affected foot loading. Participants preferred wedges which produced ankle moment zero crossing timing, peak internal knee extension moment timing, and roll-over shape center of curvature anterior-posterior position close to that of able-bodied individuals. Clinical relevance Adjusting the heel wedge is a simple, straightforward way to adjust the orthosis-heel wedge-shoe system. Changing wedge height and durometer significantly alters loading of the foot and has great potential to improve an individual's gait.

  18. Venous Thromboembolism in Patients With Thrombocytopenia

    DEFF Research Database (Denmark)

    Bælum, Jens Kristian; Ellingsen Moe, Espen; Nybo, Mads

    2017-01-01

    BACKGROUND: Venous thromboembolism (VTE) is a frequent and potentially lethal condition. Venous thrombi are mainly constituted of fibrin and red blood cells, but platelets also play an important role in VTE formation. Information about VTE in patients with thrombocytopenia is, however, missing. O...

  19. Venous and arterial thrombosis in dialysis patients

    NARCIS (Netherlands)

    Ocak, Gurbey; Vossen, Carla Y.; Rotmans, Joris I.; Lijfering, Willem M.; Rosendaal, Frits R.; Parlevliet, Karien J.; Krediet, Ray T.; Boeschoten, Els W.; Dekker, Friedo W.; Verduijn, Marion

    2011-01-01

    Whether the risk of both venous and arterial thrombosis is increased in dialysis patients as compared to the general population is unknown. In addition, it is unknown which subgroups are at highest risk. Furthermore, it is unknown whether having a history of venous thrombosis or arterial thrombosis

  20. An unusual Complication of Central Venous Cannulation

    Directory of Open Access Journals (Sweden)

    Ashvini Kumar

    2013-04-01

    Full Text Available Central venous catheter (CVC hub fracture is a rare complication of central venous cannulation. We report a case where catheter hub fracture was detected immediately after CVC insertion. Causes of catheter hub fracture and its complications are discussed.

  1. Pulmonary venous abnormalities encountered on pre ...

    African Journals Online (AJOL)

    Multidetector computed tomography (MDCT) elegantly renders pulmonary venous anatomy. With increasing numbers of radiofrequency ablation procedures being performed, there is now a greater emphasis on pre-procedure imaging to delineate this anatomy. Pulmonary venous mapping studies can be performed with or ...

  2. VENOUS THROMBOEMBOLISM PROPHYLAXIS – THE OTHER ...

    African Journals Online (AJOL)

    VENOUS THROMBOEMBOLISM PROPHYLAXIS – THE OTHER SIDE OF THE COIN: A REVIEW OF LITERATURE ... Background: There are no local guidelines for prophylaxis against Venous Thrombo-Embolism (VTE). In the absence of any .... of leg ulceration in the age matched general population. (9.6% to 12.6%).

  3. Sex-specific aspects of venous thrombosis

    NARCIS (Netherlands)

    Roach, Rachel Elizabeth Jo

    2014-01-01

    Venous thrombosis is a disease that occurs in 1-2 per 1000 people per year. At the time of their first venous thrombosis, approximately 50% of women are exposed to reproductive risk factors (oral contraception, postmenopausal hormone therapy, pregnancy and the puerperium). In this thesis, we showed

  4. Thromboelastography in patients with cerebral venous thrombosis

    NARCIS (Netherlands)

    Koopman, Karen; Uyttenboogaart, Maarten; Hendriks, Herman G. D.; Luijckx, Gert-Jan; Cramwinckel, Ivo R.; Vroomen, Patrick C.; De Keyser, Jacques; van der Meer, Jan

    Introduction: Cerebral venous thrombosis (CVT) is a rare presentation of venous thrombosis and has been associated with many conditions. In about 20% no risk factor is identified. The aim of this study was to assess the clot formation by thromboelastography (TEG) in patients with a history of CVT

  5. Starling curves and central venous pressure

    NARCIS (Netherlands)

    C. Berlin (Cheryl); J. Bakker (Jan)

    2014-01-01

    textabstractRecent studies challenge the utility of central venous pressure monitoring as a surrogate for cardiac preload. Starting with Starling’s original studies on the regulation of cardiac output, this review traces the history of the experiments that elucidated the role of central venous

  6. Heritability of chronic venous disease

    Science.gov (United States)

    Krusche, Petra; Wolf, Andreas; Krawczak, Michael; Timm, Birgitt; Nikolaus, Susanna; Frings, Norbert; Schreiber, Stefan

    2010-01-01

    Varicose veins without skin changes have a prevalence of approximately 20% in Northern and Western Europe whereas advanced chronic venous insufficiency affects about 3% of the population. Genetic risk factors are thought to play an important role in the aetiology of both these chronic venous diseases (CVD). We evaluated the relative genetic and environmental impact upon CVD risk by estimating the heritability of the disease in 4,033 nuclear families, comprising 16,434 individuals from all over Germany. Upon clinical examination, patients were classified according to the CEAP guidelines as either C2 (simple varicose veins), C3 (oedema), C4 (skin changes without ulceration), C5 (healed ulceration), or C6 (active ulcers). The narrow-sense heritability (h2) of CVD equals 17.3% (standard error 2.5%, likelihood ratio test P = 1.4 × 10−13). The proportion of disease risk attributable to age (at ascertainment) and sex, the two main risk factors for CVD, was estimated as 10.7% (Kullback–Leibler deviance R2). The heritability of CVD is high, thereby suggesting a notable genetic component in the aetiology of the disease. Systematic population-based searches for CVD susceptibility genes are therefore warranted. PMID:20354728

  7. Compression for venous leg ulcers.

    Science.gov (United States)

    O'Meara, Susan; Cullum, Nicky A; Nelson, E Andrea

    2009-01-21

    Around one percent of people in industrialised countries will suffer from a leg ulcer at some time. The majority of these leg ulcers are due to problems in the veins, resulting in an accumulation of blood in the legs. Leg ulcers arising from venous problems are called venous (varicose or stasis) ulcers. The main treatment has been a firm compression garment (bandage or stocking) in order to aid venous return. There is a large number of compression garments available and it is unclear whether they are effective in treating venous ulcers and which compression garment is the most effective. To undertake a systematic review of all randomised controlled trials of the clinical effectiveness of compression bandage or stocking systems in the treatment of venous leg ulceration.Specific questions addressed by the review are:1. Does the application of compression bandages or stockings aid venous ulcer healing? 2. Which compression bandage or stocking system is the most effective? For this update we searched the Cochrane Wounds Group Specialised Register (14/10/08); The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4 2008); Ovid MEDLINE (1950 to October Week 1 2008); Ovid EMBASE (1980 to 2008 Week 41) and Ovid CINAHL (1982 to October Week 1 2008). No date or language restrictions were applied. Randomised controlled trials recruiting people with venous leg ulceration that evaluated any type of compression bandage system or compression hosiery were eligible for inclusion. Comparators included no compression (e.g. primary dressing alone, non-compressive bandage) or an alternative type of compression. Trials had to report an objective measure of ulcer healing in order to be included (primary outcome for the review). Secondary outcomes of the review included ulcer recurrence, costs, quality of life, pain, adverse events and withdrawals. There was no restriction on date, language or publication status of trials. Details of eligible studies were

  8. [Central venous blood gas analysis].

    Science.gov (United States)

    Marano, Marco; D'Amato, Anna; Guiotto, Giovanna; Schiraldi, Fernando

    2015-01-01

    The hemodialysis might interfere with patients hemodynamic, as the technique allows a sophisticated game with extra and intravascular fluids. As the cardiocirculatory response could sometimes be unpredictable, it is interesting to collect valuable information by reaching a deep understanding of the tissue metabolism which is mirrored by the blood gas analysis of variations in arterial and central venous blood samples. Particularly interesting are the time course variations of the central venous hemoglobin saturation (ScvO2), which are directly related to the patient with O2-demand as well as to the O2-Delivery (DO2). The ScvO2 is determined by four parameters (cardiac output, Hb concentration, arterial Hb saturation and O2 consumption): If the fluids subtraction during dialysis was about to determine an occult hypoperfusion, the ScvO2 reduction would be a timely warning sign to be considered. Moreover, while the normal veno-arterial PCO2 difference is 2-4 mmHg, whenever a mismatch between O2-demand and DO2arise, a larger v-aPCO2 difference should be observed.

  9. [Physiopathology of superficial venous circulation in athletes].

    Science.gov (United States)

    Venerando, A; Pelliccia, A

    1981-01-01

    The venous circulation in athletes doing sports involving medium or heavy cardiac strain means that considerable physiological modifications may occur, notably vascular expansion. This phenomenon may be observed in the superficial venous circulation of both the upper and lower members, as well as in pulmonary circulation. Varices of the lower members are common in about 5% of practising athletes, notably in weight-lifters and wrestlers who are particularly prone to this risk, and precisely because venous return is impeded by the predominantly static effort which characterizes these sports. Karate, judo, canoeing, football, high jump and long jump are similar: mechanical blocks or sudden increases of venous pressure following the rapid changes in body-position or particular posture. Nevertheless, these phenomena can only be explained by the supposition that the valvular mechanism of certain subjects is particularly vulnerable. There are other sports, on the other hand, which have a beneficial effect on venous return, especially swimming and long-distance running.

  10. Clinical quality indicators of venous leg ulcers

    DEFF Research Database (Denmark)

    Kjaer, Monica L; Mainz, Jan; Soernsen, Lars T

    2005-01-01

    In the clinical setting, diagnosis and treatment of venous leg ulcers can vary considerably from patient to patient. The first step to reducing this variation is to document venous leg ulcer care through use of quantitative scientific documentation principles. This requires the development of valid...... and reliable evidence-based quality indicators of venous leg ulcer care. A Scandinavian multidisciplinary, cross-sectional panel of wound healing experts developed clinical quality indicators on the basis of scientific evidence from the literature and subsequent group nominal consensus of the panel......; an independent medical doctor tested the feasibility and reliability of these clinical indicators, assessing the quality of medical technical care on 100 consecutive venous leg ulcer patients. Main outcome measures were healing, recurrence, pain, venous disease diagnosis, differential diagnosis and treatment...

  11. Postpartum venous thromboembolism: incidence and risk factors.

    Science.gov (United States)

    Tepper, Naomi K; Boulet, Sheree L; Whiteman, Maura K; Monsour, Michael; Marchbanks, Polly A; Hooper, W Craig; Curtis, Kathryn M

    2014-05-01

    To calculate incidence of postpartum venous thromboembolism by week after delivery and to examine potential risk factors for venous thromboembolism overall and at different times during the postpartum period. A deidentified health care claims information database from employers, health plans, hospitals, and Medicaid programs across the United States was used to identify delivery hospitalizations among women aged 15-44 years during the years 2005-2011. International Classification of Diseases, 9th Revision, Clinical Modification diagnosis and procedure codes were used to identify instances of venous thromboembolism and associated characteristics and conditions among women with recent delivery. Incidence proportions of venous thromboembolism by week postpartum through week 12 were calculated per 10,000 deliveries. Logistic regression was used to calculate odds ratios for selected risk factors among women with postpartum venous thromboembolism and among women with venous thromboembolism during the early or later postpartum periods. The incidence proportion of postpartum venous thromboembolism was highest during the first 3 weeks after delivery, dropping from nine per 10,000 during the first week to one per 10,000 at 4 weeks after delivery and decreasing steadily through the 12th week. Certain obstetric procedures and complications such as cesarean delivery, preeclampsia, hemorrhage, and postpartum infection conferred an increased risk for venous thromboembolism (odds ratios ranging from 1.3 to 6.4), which persisted over the 12-week period compared with women without these risk factors. Risk for postpartum venous thromboembolism is highest during the first 3 weeks after delivery. Women with obstetric complications are at highest risk for postpartum venous thromboembolism, and this risk remains elevated throughout the first 12 weeks after delivery. II.

  12. Current issues in the design and analysis of stepped wedge trials.

    Science.gov (United States)

    Hughes, James P; Granston, Tanya S; Heagerty, Patrick J

    2015-11-01

    The use of stepped wedge designs in cluster-randomized trials and implementation studies has increased rapidly in recent years but there remains considerable debate regarding the merits of the design. We discuss three key issues in the design and analysis of stepped wedge trials - time-on-treatment effects, treatment effect heterogeneity and cohort studies. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Optimization of parameters on material removal rate in micro-WEDG ...

    African Journals Online (AJOL)

    In this work, an orthogonal array, signal to noise (S/N) ratio and Pareto analysis of variance (ANOVA) are employed to analyze the effect of the micro-WEDG parameters such as feed rate, capacitance and voltage on MRR. This paper focuses on the Taguchi technique for the optimization in micro-WEDG process to achieve ...

  14. Triangular metal wedges for subwavelength plasmon-polariton guiding at telecom wavelengths

    DEFF Research Database (Denmark)

    Boltasseva, Alexandra; Volkov, V.S.; Nielsen, Rasmus Bundgaard

    2008-01-01

    We report on subwavelength plasmon-polariton guiding by triangular metal wedges at telecom wavelengths. A high-quality fabrication procedure for making gold wedge waveguides, which is also mass- production compatible offering large-scale parallel fabrication of plasmonic components, is developed...

  15. Preliminary analysis of coil wedge dimensional variation in SSC Prototype Dipole Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Pollock, D.; Brown, G.; Dwyer, S.; Gattu, R.; Warner, D.

    1993-05-01

    The wedges used in SSC Prototype Dipole Magnets determine the relative position of conductor blocks within magnet coils. They serve to compensate partially for the less than full keystoning of the superconductor cable and to adjust current distribution with azimuth to determine the magnetic field shape. The ability to control the size and uniformity of wedges therefore is an important factor influencing magnet quality. This paper presents preliminary results of a Statistical Quality Control study of wedge dimensional variation and predicted field quality. Dimensions of samples from outer wedges for magnet DCA102 have been measured using a programmable optical comparator. The data is used to evaluate wedge manufacturing process capability, wedge uniformity, and to predict changes in conductor block position due to wedge deviation. Expected multipole variation attributable to observed wedge variation is discussed. This work focuses on a Prototype Dipole Magnet being built at the SSCL Magnet Development Laboratory (SSCL MDL) in Waxahachie, Texas. The magnet is of the same design as the DCA3xx series magnets built at Fermi National Accelerator Laboratory (FNAL) in 1991--92 and later used in the 1992 Accelerator Systems String Test (ASST).

  16. Dissolved organic carbon loss from Yedoma permafrost amplified by ice wedge thaw

    Science.gov (United States)

    Vonk, J. E.; Mann, P. J.; Dowdy, K. L.; Davydova, A.; Davydov, S. P.; Zimov, N.; Spencer, R. G. M.; Bulygina, E. B.; Eglinton, T. I.; Holmes, R. M.

    2013-09-01

    Pleistocene Yedoma permafrost contains nearly a third of all organic matter (OM) stored in circum-arctic permafrost and is characterized by the presence of massive ice wedges. Due to its rapid formation by sediment accumulation and subsequent frozen storage, Yedoma OM is relatively well preserved and highly biologically available (biolabile) upon thaw. A better understanding of the processes regulating Yedoma degradation is important to improve estimates of the response and magnitude of permafrost carbon feedbacks to climate warming. In this study, we examine the composition of ice wedges and the influence of ice wedge thaw on the biolability of Yedoma OM. Incubation assays were used to assess OM biolability, fluorescence spectroscopy to characterize the OM composition, and potential enzyme activity rates to examine the controls and regulation of OM degradation. We show that increasing amounts of ice wedge melt water in Yedoma-leached incubations enhanced the loss of dissolved OM over time. This may be attributed to the presence of low-molecular weight compounds and low initial phenolic content in the OM of ice wedges, providing a readily available substrate that promotes the degradation of Yedoma OC. The physical vulnerability of ice wedges upon thaw (causing irreversible collapse), combined with the composition of ice wedge-engrained OM (co-metabolizing old OM), underlines the particularly strong potential of Yedoma to generate a positive feedback to climate warming relative to other forms of non-ice wedge permafrost.

  17. Varying frontal thrust spacing in mono-vergent wedges: An insight ...

    Indian Academy of Sciences (India)

    Sandbox experiments are used to study frontal thrust fault spacing, which is a function of physical properties within the thrust wedge. We consider three styles of thrust progression in mono-vergent wedges: Style I, II and III. In Style I, frontal thrusts progress forelandward, maintaining a constant spacing, whereas Style II and ...

  18. Reflection of a converging cylindrical shock wave segment by a straight wedge

    Science.gov (United States)

    Gray, B.; Skews, B.

    2017-07-01

    As a converging cylindrical shock wave propagates over a wedge, the shock wave accelerates and the angle between the shock wave and the wedge decreases. This causes the conditions at the reflection point to move from what would be the irregular reflection domain for a straight shock wave into the regular reflection domain. This paper covers a largely qualitative study of the reflection of converging shock wave segments with Mach numbers between 1.2 and 2.1 by wedges inclined at angles between 15° and 60° from experimental and numerical results. The sonic condition conventionally used for predicting the type of reflection of straight shock waves was found to also be suitable for predicting the initial reflection of a curved shock wave. Initially regular reflections persisted until the shock was completely reflected by the wedge, whereas the triple point of initially irregular reflections was observed to return to the wedge surface, forming transitioned regular reflection. After the incident shock wave was completely reflected by the wedge, a shock wave focusing mechanism was observed to amplify the pressure on the surface of the wedge by a factor of up to 100 for low wedge angles.

  19. Wedge factor constituents of high energy photon beams: field size and depth dependence.

    Science.gov (United States)

    Heukelom, S; Lanson, J H; Mijnheer, B J

    1994-01-01

    Wedge factors have been determined as a function of field size and phantom depth for a 60Co gamma-ray beam and X-ray beams in the range from 4 MV to 25 MV. The results show an increase of the wedge factor with field size, up to 9.1% for the 25 MV X-ray beam. The magnitude of this increase is a linear function of the product of that part of the irradiated wedge volume that can be observed from the point of measurement, its mass energy-absorption coefficient and mass density. This relationship is independent of the photon beam energy, the type of wedge material and the wedge angle. Differences in variation of the amount of backscatter to the monitor with field size for the open and wedged photon beam yielded only a minor influence, up to 0.7%. For the 4-16 MV X-ray beams the wedge factor increases linearly with phantom depth, almost independently of field size. For the 60Co gamma-ray beam and the 25 MV X-ray beam the wedge factor variation is a more complicated function of phantom depth for a particular field size.

  20. Static response of maximally pronated and nonmaximally pronated feet to frontal plane wedging of foot orthoses.

    Science.gov (United States)

    Pascual Huerta, Javier; Ropa Moreno, Juan Manuel; Kirby, Kevin A

    2009-01-01

    Research on foot orthoses has shown that their effect on the kinematics of the rearfoot is variable, with no consistent patterns of changes being demonstrated. It has also been hypothesized that the mechanical effect of foot orthoses could be subject specific. The purpose of our study was to determine if maximally pronated feet have a different response to frontal plane wedging of foot orthoses than do nonmaximally pronated feet during static stance. One hundred six feet of 53 healthy asymptomatic subjects were divided into two groups (maximally pronated and nonmaximally pronated) on the basis of their subtalar joint rotational position during relaxed bipedal stance. Functional foot orthoses were constructed for each subject and the relaxed calcaneal stance position was measured while standing on five separate frontal plane orthosis wedging conditions, 10 degrees valgus, 5 degrees valgus, no wedging, 5 degrees varus, and 10 degrees varus, to assess changes in calcaneal position. Relative to the no-wedging condition, there were statistically significant differences (P feet with the 10 degrees valgus and the 10 degrees varus wedging conditions. No significant differences in calcaneal position were found with the 5 degrees varus and the 5 degrees valgus wedging conditions. Our study shows that the response to foot orthoses is variable between individuals. Maximally pronated subjects do not exhibit the same response to frontal plane wedging of foot orthoses as do nonmaximally pronated with 10 degrees wedging. Intrinsic biomechanical factors such as subtalar joint position may influence the response to foot orthoses.

  1. Venous hemodynamic changes in lower limb venous disease

    DEFF Research Database (Denmark)

    Lee, Byung Boong; Nicolaides, Andrew N; Myers, Kenneth

    2016-01-01

    There are excellent guidelines for clinicians to manage venous diseases but few reviews to assess their hemodynamic background. Hemodynamic concepts that evolved in the past have largely remained unchallenged in recent decades, perhaps due to their often complicated nature and in part due...... not provide the physiological basis for understanding the hemodynamics of flow, pressure, compliance and resistance. Hemodynamic investigations appear to provide a better correlation with post-treatment clinical outcome and quality of life than ultrasound findings. There is a far better prospect...... for understanding the complete picture of the patient's disability and response to management by combining ultrasound with hemodynamic studies. Accordingly, at the instigation of Dr Angelo Scuderi, the Union Internationale de Phlebologie (UIP) executive board commissioned a large number of experts to assess all...

  2. 3D-2D registration in endovascular image-guided surgery: evaluation of state-of-the-art methods on cerebral angiograms.

    Science.gov (United States)

    Mitrović, Uroš; Likar, Boštjan; Pernuš, Franjo; Špiclin, Žiga

    2017-10-24

    Image guidance for minimally invasive surgery is based on spatial co-registration and fusion of 3D pre-interventional images and treatment plans with the 2D live intra-interventional images. The spatial co-registration or 3D-2D registration is the key enabling technology; however, the performance of state-of-the-art automated methods is rather unclear as they have not been assessed under the same test conditions. Herein we perform a quantitative and comparative evaluation of ten state-of-the-art methods for 3D-2D registration on a public dataset of clinical angiograms. Image database consisted of 3D and 2D angiograms of 25 patients undergoing treatment for cerebral aneurysms or arteriovenous malformations. On each of the datasets, highly accurate "gold-standard" registrations of 3D and 2D images were established based on patient-attached fiducial markers. The database was used to rigorously evaluate ten state-of-the-art 3D-2D registration methods, namely two intensity-, two gradient-, three feature-based and three hybrid methods, both for registration of 3D pre-interventional image to monoplane or biplane 2D images. Intensity-based methods were most accurate in all tests (0.3 mm). One of the hybrid methods was most robust with 98.75% of successful registrations (SR) and capture range of 18 mm for registrations of 3D to biplane 2D angiograms. In general, registration accuracy was similar whether registration of 3D image was performed onto mono- or biplanar 2D images; however, the SR was substantially lower in case of 3D to monoplane 2D registration. Two feature-based and two hybrid methods had clinically feasible execution times in the order of a second. Performance of methods seems to fall below expectations in terms of robustness in case of registration of 3D to monoplane 2D images, while translation into clinical image guidance systems seems readily feasible for methods that perform registration of the 3D pre-interventional image onto biplanar intra

  3. A semi-infinite crack of mode III in the bimaterial wedge

    Directory of Open Access Journals (Sweden)

    Victor V. Tikhomirov

    2016-06-01

    Full Text Available An exact solution of the antiplane problem for a semi-infinite interface crack in a piecewise-homogeneous wedge under a self-balanced load on its sides has been obtained. Three types of boundary conditions on the wedge sides were examined: the both sides being stress-free; both sides being clamped, and one side being stress-free with the second one clamped. As a result of using the Wiener–Hopf method, the solution was represented in quadratures. Green's functions were obtained for stress intensity factors; in the case of a geometrically symmetrical wedge structure simple formulae were found for these functions. The stress singularity in the apex of the wedge was studied. In contrast to the homogeneous wedge structure the asymptotic of the stresses near the apex was established to have sometimes two singular terms for some values of the composite parameters.

  4. [De Novo Cavernous Angioma Secondary to a Developmental Venous Anomaly:A Case Report and Review of the Literature].

    Science.gov (United States)

    Sakakibara, Yohtaro; Taguchi, Yoshio; Nakamura, Homare; Onodera, Hidetaka; Uchida, Masashi; Kawaguchi, Kimiyuki; Aida, Yoshio

    2017-04-01

    Previously, cavernous angiomas(CAs)have been thought to be only congenital in origin. Recently, however, a few cases of de novo CAs have been reported in the literature. We present a case of a de novo CA and discuss the etiology of the newly appeared CA. A 29-year-old man was presented to a local clinic because of hypersomnia. MRI demonstrated a heterogeneous mass peripherally located, which was in contact with a developmental venous anomaly(DVA)at the left thalamus. Six years before the presentation, he visited the same clinic because of faintness, and MRI results indicated no abnormality except for the DVA. Three weeks later, he suddenly experienced difficulty in speech, and the MRI revealed an increase in the size of the mass. Subsequently, he was admitted at our institution, and neurological examination revealed aphasia and right hemiparesis. A left carotid angiogram on venous phase showed a narrowing of the DVA, which was seen as it entered the internal cerebral vein. The diagnosis of a de novo CA was made. The mass was completely resected through the transcallosal transventricular approach to avoid injuring the DVA. The DVA could not be found during surgery. The pathological diagnosis was in line with the findings of CA. Postoperatively, the patient continued having difficulty in speech and was transferred to another institution for speech rehabilitation. Although the association of CA and DVA has been described with increasing frequencies recently, the etiology of de novo CA in the case of this association has been a matter of debate. In the present case, it was speculated that a narrowing of the DVA resulted in increased venous pressure and caused the development of de novo CA.

  5. Improved wedge method for the measurement of sub-millimeter slice thicknesses in magnetic resonance imaging.

    Science.gov (United States)

    Kanazawa, Tsutomu; Ohkubo, Masaki; Kondo, Tatsuya; Miyazawa, Takayuki; Inagawa, Shoichi

    2017-12-01

    The standard method for measuring the slice thickness of magnetic resonance images uses the inclined surface of a wedge (wedge method); it is sensitive to small increases in noise because of the differentiation of the edge response function (ERF) required. The purpose of this study was to improve the wedge method by fitting a curve to the ERF. The curve-fit function was obtained by convolving an ideal ERF (a ramp function) with a Gaussian function to represent ERF blurring. Measurements of 5- and 3-mm slice thicknesses were performed on a 3T scanner using the conventional wedge method, the improved wedge method, and another standard method using an inclined slab (slab method). Subsequently, 0.5- and 0.25-mm slice thicknesses from multiple slices acquired using a three-dimensional sequence were measured using the improved wedge method. When measuring 5-mm slices, the differences in measurements obtained using the improved wedge method and the conventional slab and wedge methods were very small: <0.6% of the 5-mm slice thickness. The difference was ≤1.7% for 3-mm slices. For 0.5- and 0.25-mm slices, the mean values obtained using the improved wedge method were 0.543 ± 0.007 mm and 0.247 ± 0.015 mm, with a 1.2 and 5.9% coefficient of variation across slices, respectively. The improved wedge method is valid and potentially applicable to the measurement of sub-millimeter slice thicknesses.

  6. Metamaterials based on wedge-shaped electrodynamic structures

    Directory of Open Access Journals (Sweden)

    Mitrokhin Vladimir

    2017-01-01

    Full Text Available The paper studies a possibility of simulation of artificial composite media with negative values of the real part of the equivalent dielectric (magnetic permittivity, by the use of segments of hollow composite waveguides with cylindrical guided waves in evanescent mode. Reactive evanescent fields of wedge-shaped waveguide eigenmodes are formed in the evanescent region before the critical section of the waveguide which separates the quasistatic field region from the distributing field of the evanescent waveguide mode. The possibility of simulation is determined by the equivalence of dispersion equation of the eigenmode propagation constant and the dispersion equation for the electric (magnetic permittivity of plasma-like medium if cut-off frequency and electric (magnetic plasma frequency of the medium are equal.

  7. Two-dimensional electronic spectroscopy with birefringent wedges

    Energy Technology Data Exchange (ETDEWEB)

    Réhault, Julien; Maiuri, Margherita; Oriana, Aurelio; Cerullo, Giulio [IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2014-12-15

    We present a simple experimental setup for performing two-dimensional (2D) electronic spectroscopy in the partially collinear pump-probe geometry. The setup uses a sequence of birefringent wedges to create and delay a pair of phase-locked, collinear pump pulses, with extremely high phase stability and reproducibility. Continuous delay scanning is possible without any active stabilization or position tracking, and allows to record rapidly and easily 2D spectra. The setup works over a broad spectral range from the ultraviolet to the near-IR, it is compatible with few-optical-cycle pulses and can be easily reconfigured to two-colour operation. A simple method for scattering suppression is also introduced. As a proof of principle, we present degenerate and two-color 2D spectra of the light-harvesting complex 1 of purple bacteria.

  8. The Cimmerian accretionary wedge of Anarak, Central Iran

    Science.gov (United States)

    Zanchi, Andrea; Malaspina, Nadia; Zanchetta, Stefano; Berra, Fabrizio; Benciolini, Luca; Bergomi, Maria; Cavallo, Alessandro; Javadi, Hamid Reza; Kouhpeyma, Meyssam

    2015-04-01

    The occurrence in Iran of several ophiolite belts dating between Late Palaeozoic to Triassic poses several questions on the possible existence of various sutures marking the closure of the Palaeotethys ocean between Eurasia and this Gondwana-derived microplate. In this scenario, the Anarak region in Central Iran still represents a conundrum. Contrasting geochronological, paleontological, paleomagnetic data and reported field evidence suggest different origins for the Anarak Metamorphic Complex (AMC). The AMC is either interpreted, as: (1) relict of an accretionary wedge developed at the Eurasia margin during the Palaeotethys subduction as part of the Cimmerian suture zone of NE Iran, displaced to Central Iran by a large counter-clockwise rotation of the central Iranian blocks; (2) autochthonous unit forming a secondary branch of the main suture zone. Our structural, petrographic and geochemical data indicate that the AMC consists of several metamorphic units also including dismembered "ophiolites" which display different tectono-metamorphic evolutions. Three main ductile deformational events can be distinguished in the AMC. The Morghab and Chah Gorbeh complexes preserve a different M1 metamorphism, characterized by blueschist relics in the S1 foliation of the former unit, and greenschist assemblages in the latter. They share a subsequent similar D2 deformational and M2 metamorphic history, showing a prograde metamorphism with syn- to post-deformation growth of blueschist facies mineral assemblages on pre-existing greenschist facies associations. High pressure, low temperature (HP/LT) metamorphism responsible for the growth of sodic amphibole has been recognized also within marble lenses at the contact between the Chah Gorbeh Complex and serpentinites. Evidence of HP/LT metamorphism also occurs in glaucophane-bearing meta-pillow lavas and serpentinites, which contain antigorite and form most of the "ophiolites" within the AMC. Structural relationships show that the

  9. Familial Clustering of Venous Thromboembolism

    DEFF Research Database (Denmark)

    Sindet-Pedersen, Caroline; Oestergaard, Louise Bruun; Gundlund, Anna

    2016-01-01

    BACKGROUND: Identification of risk factors for venous thromboembolism (VTE) is of utmost importance to improve current prophylactic regimes and treatment guidelines. The extent to which a family history contributes to the risk of VTE needs further exploration. OBJECTIVES: To examine the relative...... rate of VTE in first-degree relatives compared with the general population. METHODS: By crosslinking Danish nationwide registries we identified patients with VTE between 1978 and 2012, and their familial relations. The first member in a family to acquire VTE was defined as the proband. All first...... regression models, with the general population as a fixed reference. RESULTS: We identified 70,767 children of maternal probands, 66,065 children of paternal probands, and 29,183 siblings to sibling probands. Having a maternal proband or a paternal proband were associated with a significantly increased VTE...

  10. The Substorm Current Wedge: Further Insights from MHD Simulations

    Science.gov (United States)

    Birn, J.; Hesse, M.

    2015-01-01

    Using a recent magnetohydrodynamic simulation of magnetotail dynamics, we further investigate the buildup and evolution of the substorm current wedge (SCW), resulting from flow bursts generated by near-tail reconnection. Each flow burst generates an individual current wedge, which includes the reduction of cross-tail current and the diversion to region 1 (R1)-type field-aligned currents (earthward on the dawn and tailward on the duskside), connecting the tail with the ionosphere. Multiple flow bursts generate initially multiple SCW patterns, which at later times combine to a wider single SCW pattern. The standard SCWmodel is modified by the addition of several current loops, related to particular magnetic field changes: the increase of Bz in a local equatorial region (dipolarization), the decrease of |Bx| away from the equator (current disruption), and increases in |By| resulting from azimuthally deflected flows. The associated loop currents are found to be of similar magnitude, 0.1-0.3 MA. The combined effect requires the addition of region 2 (R2)-type currents closing in the near tail through dawnward currents but also connecting radially with the R1 currents. The current closure at the inner boundary, taken as a crude proxy of an idealized ionosphere, demonstrates westward currents as postulated in the original SCW picture as well as North-South currents connecting R1- and R2-type currents, which were larger than the westward currents by a factor of almost 2. However, this result should be applied with caution to the ionosphere because of our neglect of finite resistance and Hall effects.

  11. Platelet recruitment to venous stent thrombi.

    Science.gov (United States)

    McBane, Robert D; Karnicki, Krzysztof; Wysokinski, Waldemar E

    2013-11-01

    Thrombosis following venous stent placement is a morbid clinical outcome. Whether to target platelets or coagulation factors for venous stent thromboprophylaxis remains unclear. We sought to determine whether integrin α(IIb)β3 antagonism with lamifiban would inhibit platelet recruitment to venous stent thrombosis. Anti-thrombotic efficacy was compared between venous and arterial circulations. Pigs received either lamifiban (0.2 mg/kg bolus plus 0.2 mg/kg/h infusion; n = 6) or saline (n = 12). Carotid arteries were crush injured and then harvested 30 min later to provide an assessment of antithrombotic efficacy in the arterial circulation. Iliac venous stents were then deployed and thrombi allowed to propagate for 2 h before harvesting. Platelet deposition was measured by scintillation detection of autologous (111)In-platelets. Venous thrombi were quantified by weight and compared to platelet, Von Willebrand factor (VWF) and fibrinogen content. Arterial platelet deposition (×10(6)/cm(2)) was reduced >80% by lamifiban (398 ± 437) compared to controls (1,540 ± 883; p thrombi occurs in part through the integrin α(IIb)β3 receptor. Unlike arterial thrombosis, inhibition of this receptor is insufficient to prevent venous stent thrombosis.

  12. A level-set method for pathology segmentation in fluorescein angiograms and en face retinal images of patients with age-related macular degeneration

    Science.gov (United States)

    Mohammad, Fatimah; Ansari, Rashid; Shahidi, Mahnaz

    2013-03-01

    The visibility and continuity of the inner segment outer segment (ISOS) junction layer of the photoreceptors on spectral domain optical coherence tomography images is known to be related to visual acuity in patients with age-related macular degeneration (AMD). Automatic detection and segmentation of lesions and pathologies in retinal images is crucial for the screening, diagnosis, and follow-up of patients with retinal diseases. One of the challenges of using the classical level-set algorithms for segmentation involves the placement of the initial contour. Manually defining the contour or randomly placing it in the image may lead to segmentation of erroneous structures. It is important to be able to automatically define the contour by using information provided by image features. We explored a level-set method which is based on the classical Chan-Vese model and which utilizes image feature information for automatic contour placement for the segmentation of pathologies in fluorescein angiograms and en face retinal images of the ISOS layer. This was accomplished by exploiting a priori knowledge of the shape and intensity distribution allowing the use of projection profiles to detect the presence of pathologies that are characterized by intensity differences with surrounding areas in retinal images. We first tested our method by applying it to fluorescein angiograms. We then applied our method to en face retinal images of patients with AMD. The experimental results included demonstrate that the proposed method provided a quick and improved outcome as compared to the classical Chan-Vese method in which the initial contour is randomly placed, thus indicating the potential to provide a more accurate and detailed view of changes in pathologies due to disease progression and treatment.

  13. Vertebral body or intervertebral disc wedging: which contributes more to thoracolumbar kyphosis in ankylosing spondylitis patients?

    Science.gov (United States)

    Liu, Hao; Qian, Bang-Ping; Qiu, Yong; Wang, Yan; Wang, Bin; Yu, Yang; Zhu, Ze-Zhang

    2016-01-01

    Abstract Both vertebral body wedging and disc wedging are found in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis. However, their relative contribution to thoracolumbar kyphosis is not fully understood. The objective of this study was to compare different contributions of vertebral and disc wedging to the thoracolumbar kyphosis in AS patients, and to analyze the relationship between the apical vertebral wedging angle and thoracolumbar kyphosis. From October 2009 to October 2013, a total of 59 consecutive AS patients with thoracolumbar kyphosis with a mean age of 38.1 years were recruited in this study. Based on global kyphosis (GK), 26 patients with GK < 70° were assigned to group A, and the other 33 patients with GK ≥ 70° were included in group B. Each GK was divided into disc wedge angles and vertebral wedge angles. The wedging angle of each disc and vertebra comprising the thoracolumbar kyphosis was measured, and the proportion of the wedging angle to the GK was calculated accordingly. Intergroup and intragroup comparisons were subsequently performed to investigate the different contributions of disc and vertebra to the GK. The correlation between the apical vertebral wedging angle and GK was calculated by Pearson correlation analysis. The duration of disease and sex were also recorded in this study. With respect to the mean disease duration, significant difference was observed between the two groups (P < 0.01). The wedging angle and wedging percentage of discs were significantly higher than those of vertebrae in group A (34.8° ± 2.5° vs 26.7° ± 2.7°, P < 0.01 and 56.6% vs 43.4%, P < 0.01), whereas disc wedging and disc wedging percentage were significantly lower than vertebrae in group B (37.6° ± 7.0° vs 50.1° ± 5.1°, P < 0.01 and 42.7% vs 57.3%, P < 0.01). The wedging of vertebrae was significantly higher in group B than in group A (50.1° ± 5.1° vs 26.7° ± 2.7°, P < 0

  14. Mechanism of bone incorporation of beta-TCP bone substitute in open wedge tibial osteotomy in patients.

    NARCIS (Netherlands)

    Gaasbeek, R.D.A.; Toonen, H.G.; Heerwaarden, R.J. van; Buma, P.

    2005-01-01

    A histological study was performed of bone biopsies from 16 patients (17 biopsies) treated with open wedge high tibial osteotomies for medial knee osteoarthritis. The open wedge osteotomies were filled with a wedge of osteoconductive beta tricalcium phosphate (beta-TCP) ceramic bone replacement. At

  15. 76 FR 52313 - Heavy Forged Hand Tools (i.e., Axes & Adzes, Bars & Wedges, Hammers & Sledges, and Picks...

    Science.gov (United States)

    2011-08-22

    ... International Trade Administration Heavy Forged Hand Tools (i.e., Axes & Adzes, Bars & Wedges, Hammers & Sledges... & Adzes, Bars & Wedges, Hammers & Sledges, and Picks & Mattocks) (``Hand Tools'') from the People's... & Wedges, Hammers & Sledges, and Picks & Mattocks) From the People's Republic of China: Final Results of...

  16. Yield of computed tomography pulmonary angiogram in the emergency department in cancer patients suspected to have pulmonary embolism.

    Science.gov (United States)

    Tannous, Pierre; Mukadam, Zubin; Kammari, Chetan; Banavasi, Harsha; Soubani, Ayman O

    2016-12-01

    The use of computed tomography pulmonary angiography (CTPA) in the emergency department (ED) for patients suspected to have pulmonary embolism (PE) has been steadily rising in the last 2decades. However, there are limited studies that specifically address the use of CTPA in the ED for cancer patients suspected to have PE. The objective of this study is to assess the rate of positive PE by CTPA in the ED in cancer patients and the variables that are associated with positive results. A retrospective review of electronic medical records for 208 consecutive patients with cancer who presented to the ED and received a CTPA for suspected PE over a 12-month period. The review included demographics, type and status of cancer, presenting symptoms, CTPA results, calculation of Wells Score, management based on CT findings, and outcome of patients. Among the 208 patients who met the inclusion criteria during our study period (mean age 57±13.37years, 73% women, 59% African American, and 32% Caucasians), 5.7% were diagnosed with PE. One hundred and eighty-two (83.7%) had a Wells Score ⩽4, of which 2.2% were found to have to have PE, 22 (16.3%) patients had a Wells Score >4, of which 36.4% were found to have PE (p4 was 66.7% and 92.9%, respectively, with an odds ratio of 27 (95% CI 6.6-113.6). Receiver operator characteristics area under the curve for Wells Score was 0.868. Age, race, sex, malignancy type, stage, status, clinical presentation, D-dimer, and a previous history of venous thromboembolism were not found to have statistically significant predictive values. The yield of CTPA to rule out PE in patients with cancer presenting in the ED is low. Following a validated decision-making protocol such as Wells Criteria may significantly decrease the number of CTPA used in the ED. Copyright © 2016 King Faisal Specialist Hospital & Research Centre. Published by Elsevier Ltd. All rights reserved.

  17. Central venous catheters: the role of radiology

    Energy Technology Data Exchange (ETDEWEB)

    Tan, P.L. [Department of Radiology, John Radcliffe Hospital, Oxford (United Kingdom)]. E-mail: pecklingtan@hotmail.com; Gibson, M. [Department of Radiology, Royal Berkshire Hospital, Reading, Berkshire (United Kingdom)

    2006-01-15

    The insertion and management of long-term venous catheters have long been the province of anaesthetists, intensive care physicians and surgeons. Radiologists are taking an increasing role in the insertion of central venous catheters (CVCs) because of their familiarity with the imaging equipment and their ability to manipulate catheters and guide-wires. The radiological management of the complications of CVCs has also expanded as a result. This article reviews the role of radiology in central venous access, covering the detection and management of their complications.

  18. Quality of life in patients with venous stasis ulcers and others with advanced venous insufficiency.

    Science.gov (United States)

    Tracz, Edyta; Zamojska, Ewa; Modrzejewski, Andrzej; Zaborski, Daniel; Grzesiak, Wilhelm

    2015-01-01

    The quality of life (QoL) in patients with advanced venous insufficiency (including venous stasis ulcers, skin discoloration, stasis eczema, and lipodermatosclerosis) assessed using the Clinical Etiological Anatomical Pathophysiological (CEAP) and Venous Clinical Severity Score (VCSS) classifications is presented. Also, disease features such as: intensity of pain, edema and inflammatory response that exerted the most profound effect on different domains of QoL are reported. The global QoL in patients with lower leg venous ulcerations was relatively similar to that observed in other patients with chronic venous insufficiency. The presence of venous ulcerations was associated with lower QoL in a Physical domain. Significant correlations were found between pain intensity and the values of Physical, Physiological, Level of Independence and Environmental domains, between edema intensity and Social domain as well as between the intensity of inflammatory response and Physical and Spiritual domains.

  19. The Impact of Lower Extremity Venous Ulcers due to Chronic Venous Insufficiency on Quality of Life

    OpenAIRE

    Koupidis, Sotirios A; Paraskevas, Kosmas I.; Stathopoulos, Vassilios; Mikhailidis, Dimitri P.

    2008-01-01

    Lower extremity venous ulcers comprise a complex medical and social issue. The conservative and/or surgical management of venous ulcers is often inadequate. In addition, the psychosocial aspect of the disease is often overlooked and most often undertreated. Common symptoms such as pain, low self-esteem and patient isolation are usually not recognized and therefore not adequately managed. This mini-review summarizes the current data on the management of lower extremity venous ulcers and their ...

  20. Central Venous Line Insertion Revealing Partial Anomalous Pulmonary Venous Return: Diagnosis and Management

    Directory of Open Access Journals (Sweden)

    Bashar Alzghoul

    2017-01-01

    Full Text Available Central venous line malposition is a well-known complication of line insertion. Rarely, it can be mal-positioned in an anomalous pulmonary vein. We present an unusual case of a 56-year-old woman that was found to have partial anomalous pulmonary venous return on central venous line insertion. In this report, we describe a systematic approach to diagnosis and management of this unusual situation.

  1. Central Venous Line Insertion Revealing Partial Anomalous Pulmonary Venous Return: Diagnosis and Management.

    Science.gov (United States)

    Alzghoul, Bashar; Innabi, Ayoub; Chada, Aditya; Tarawneh, Ahmad R; Kakkera, Krishna; Khasawneh, Khaled

    2017-01-01

    Central venous line malposition is a well-known complication of line insertion. Rarely, it can be mal-positioned in an anomalous pulmonary vein. We present an unusual case of a 56-year-old woman that was found to have partial anomalous pulmonary venous return on central venous line insertion. In this report, we describe a systematic approach to diagnosis and management of this unusual situation.

  2. The possibility for use of venous flaps in plastic surgery

    Energy Technology Data Exchange (ETDEWEB)

    Baytinger, V. F., E-mail: baitinger@mail.tomsknet.ru; Kurochkina, O. S., E-mail: kurochkinaos@yandex.ru; Selianinov, K. V.; Baytinger, A. V. [Research Institute of Microsurgery, Tomsk (Russian Federation); Dzyuman, A. N. [Siberian State Medical University, Tomsk (Russian Federation)

    2015-11-17

    The use of venous flaps is controversial. The mechanism of perfusion of venous flaps is still not fully understood. The research was conducted on 56 white rats. In our experimental work we studied two different models of venous flaps: pedicled venous flap (PVF) and pedicled arterialized venous flap (PAVF). Our results showed that postoperative congestion was present in all flaps. However 66.7% of all pedicled venous flaps and 100% of all pedicled arterialized venous flaps eventually survived. Histological examination revealed that postoperatively the blood flow in the skin of the pedicled arterialized venous flap became «re-reversed» again; there were no differences between mechanism of survival of venous flaps and other flaps. On the 7-14th day in the skin of all flaps were processes of neoangiogenesis and proliferation. Hence the best scenario for the clinical use of venous flaps unfolds when both revascularization and skin coverage are required.

  3. The possibility for use of venous flaps in plastic surgery

    Science.gov (United States)

    Baytinger, V. F.; Kurochkina, O. S.; Selianinov, K. V.; Baytinger, A. V.; Dzyuman, A. N.

    2015-11-01

    The use of venous flaps is controversial. The mechanism of perfusion of venous flaps is still not fully understood. The research was conducted on 56 white rats. In our experimental work we studied two different models of venous flaps: pedicled venous flap (PVF) and pedicled arterialized venous flap (PAVF). Our results showed that postoperative congestion was present in all flaps. However 66.7% of all pedicled venous flaps and 100% of all pedicled arterialized venous flaps eventually survived. Histological examination revealed that postoperatively the blood flow in the skin of the pedicled arterialized venous flap became «re-reversed» again; there were no differences between mechanism of survival of venous flaps and other flaps. On the 7-14th day in the skin of all flaps were processes of neoangiogenesis and proliferation. Hence the best scenario for the clinical use of venous flaps unfolds when both revascularization and skin coverage are required.

  4. Statistical mechanics of fluids adsorbed in planar wedges: finite contact angle.

    Science.gov (United States)

    Henderson, J R

    2004-06-01

    I consider the statistical mechanics of inhomogeneous fluids applied to fluids adsorbed in planar wedges. Exact results are described that belong to an infinite subset of models defined as the intersection of any two identical semi-infinite planar wall-fluid potentials. This geometry is interesting as a generic example of adsorption onto structured interfaces and of interfacial phase transitions controlled by the substrate geometry. Previously described virial theorems are extended to the case of a general wall-fluid model. This enables the consideration of wedge filling when Young's contact angle far from the wedge apex is finite. The virial theorems generate two important relations: the wedge sum rules. The first sum rule links the interfacial free energy far from the wedge apex to the structure induced at the apex. The second sum rule links the free energy of the apex region to the structure induced by the apex. When Young's contact angle at the wedge walls is finite these relations further yield an exact result for the macroscopic contact angle in terms of the nanoscopic structure at the three-phase contact line (the intersection of the liquid-vapor surface with a wedge wall): the contact angle sum rule. These exact results are of direct relevance to computer simulation studies of adsorbed films. In addition, they take on special significance in the vicinity of continuous interfacial phase transitions: an approach to complete filling and the filling transition at bulk liquid-vapor coexistence.

  5. Spontaneous thrombosis of developmental venous anomaly (DVA) with venous infarct and acute cerebellar ataxia.

    Science.gov (United States)

    Agarwal, Amit; Kanekar, Sangam; Kalapos, Paul; Vijay, Kanupriya

    2014-08-01

    Developmental venous anomaly (DVA), formally known as venous angioma, is a congenital anatomic variant of the venous drainage of the brain. Although they typically have a benign clinical course and a low symptomatic rate, thrombosis of a drainage vein may occur, leading to potentially debilitating complications. We report a unique case of spontaneous thrombosis of a posterior fossa developmental venous anomaly with cerebellar infarct in a 61-year-old man who presented with acute onset cerebellar ataxia. DVA thrombosis was well-depicted on CT and MR studies. Patient was put on anticoagulant therapy and complete recanalization was seen on follow-up imaging.

  6. Onset of flow separation for the oblique water impact of a wedge

    Science.gov (United States)

    Semenov, Yuriy A.; Yoon, Bum-Sang

    2009-11-01

    For the oblique impact of a wedge on a liquid half space, the limiting angles of the entry velocity and the wedge orientation corresponding to flow separation from the wedge vertex during the initial stage of the impact are investigated on the basis of an analytical solution of the problem. The liquid is assumed to be ideal and incompressible; gravity, surface tension, and air cushioning effects are ignored. The flow generated by the impact is two dimensional and potential. The solution is presented in terms of two governing expressions, which are the complex velocity and the derivative of the complex potential defined in a parameter region. These expressions are obtained using generalized integral formulas for solving mixed and uniform boundary-value problems for the first quadrant. They include two unknown functions, which are the velocity magnitude and angle to the free surface determined from the dynamic and kinematic boundary conditions. The obtained system of integral equations is solved by using the method of successive approximations. The effect of the horizontal component of the entry velocity is studied for various wedge orientations. The analysis of the computations revealed configurations of the impact such that the pressure along the whole length of one side of the wedge becomes less than the pressure on the free surface. Although air effects are not included in the analysis, such a pressure distribution provides conditions for the ventilation of the wedge side, which, in the presence of the air, starts from the contact point on the free surface and extends suddenly along the whole length of the wedge side, thus leading to flow separation from the wedge vertex. The theoretical predictions of flow separation and the experimental data on flow separation by Judge et al. ["Initial water impact of a wedge at vertical and oblique angles," J. Eng. Math. 48, 279 (2004)] are remarkably close to each other.

  7. Imaging of cerebral venous complications in patients with infections

    Directory of Open Access Journals (Sweden)

    Xudong Shen

    2017-09-01

    Full Text Available Systemic and local infections can cause cerebrovascular complications in the central nervous system. The involvement of cerebral venous system would result in venous or dural venous sinus thrombophlebitis. Images can help evaluate the venous complications in patients with central nervous system infection and provide information in guiding treatment and prognosis. The main focus of this review is to emphasize the proper utilization of imaging modalities in assessment the complications of cerebral venous system in patients with infection.

  8. [Emphysematous gastritis with concomitant portal venous air].

    Science.gov (United States)

    Jeong, Min Yeong; Kim, Jin Il; Kim, Jae Young; Kim, Hyun Ho; Jo, Ik Hyun; Seo, Jae Hyun; Kim, Il Kyu; Cheung, Dae Young

    2015-02-01

    Emphysematous gastritis is a rare form of gastritis caused by infection of the stomach wall by gas forming bacteria. It is a very rare condition that carries a high mortality rate. Portal venous gas shadow represents elevation of intestinal luminal pressure which manifests as emphysematous gastritis or gastric emphysema. Literature reviews show that the mortality rate is especially high when portal venous gas shadow is present on CT scan. Until recently, the treatment of emphysematous gastritis has been immediate surgical intervention. However, there is a recent trend of avoiding surgery because of the frequent occurrence of post-operative complications such as anastomosis leakage. In addition, aggressive surgical treatment has failed to show significant improvement in prognosis. Recently, the authors experienced a case of emphysematous gastritis accompanied by portal venous gas which was treated successfully by conservative treatment without immediate surgical intervention. Herein, we present a case of emphysematous gastritis with concomitant portal venous air along with literature review.

  9. Tuberculosis and Venous Thromboembolism: a case series.

    Science.gov (United States)

    Goncalves, Ivone M; Alves, Daniela Costa; Carvalho, Aurora; do Ceu Brito, Maria; Calvario, Fernando; Duarte, Raquel

    2009-12-16

    Tuberculosis remains an infectious disease with a high prevalence worldwide and represents a major public health issue. Although venous thromboembolism is a rare complication of this disease, it may be a potentially life-threatening event. We report two cases of severe pulmonary tuberculosis associated with venous thromboembolism. A 38 year-old caucasian male that had a thromboembolic event as an unsual presentation form of tuberculosis and a 51 year-old caucasian male that developed deep venous thrombosis later in the course of the disease. An association between inflamation induced by tuberculosis and a hypercoagulable state has been described. Therefore, the occurence of deep venous thrombosis or pulmonary embolic episods, should be considered in patients with tuberculosis particulary during the first weeks of treatment. The physician's awarness of these phenomena is important to an early diagnostic suspicion and prompt treatment in order to prevent fatal outcomes.

  10. [Venous thromboembolic disease: presentation of a case].

    Science.gov (United States)

    Mirpuri-Mirpuri, P G; Álvarez-Cordovés, M M; Pérez-Monje, A

    2013-01-01

    Venous thromboembolic disease in its clinical spectrum includes both deep vein thrombosis and pulmonary thromboembolism, which is usually a complication of deep vein thrombosis. It is a relatively common disease with significant morbidity and requires an accurate diagnosis. They are numerous risk factors for venous thromboembolism, and there is evidence that the risk of thromboembolic disease increases proportionally to the number of predisposing risk factors present. The primary care physician should know the risk factors and suspect the presence of venous thromboembolic disease when there is a compatible clnical picture. The treatment for this pathology is anticoagulation. We report a patient with cardiovascular risk factors who was seen with pain in the right leg and shortness of breath and referred to the hospital with suspected venous thromboembolism, atrial fibrillation and pleural effusion. Copyright © 2012 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.

  11. Pathophysiology of spontaneous venous gas embolism

    Science.gov (United States)

    Lambertsen, C. J.; Albertine, K. H.; Pisarello, J. B.; Flores, N. D.

    1991-01-01

    The use of controllable degrees and durations of continuous isobaric counterdiffusion venous gas embolism to investigate effects of venous gas embolism upon blood, cardiovascular, and respiratory gas exchange function, as well as pathological effects upon the lung and its microcirculation is discussed. Use of N2O/He counterdiffusion permitted performance of the pathophysiologic and pulmonary microstructural effects at one ATA without hyperbaric or hypobaric exposures.

  12. Recent circum-Arctic ice-wedge degradation and its hydrological impacts

    Science.gov (United States)

    Liljedahl, A. K.; Boike, J.; Daanen, R. P.; Fedorov, A. N.; Frost, G. V., Jr.; Grosse, G.; Hinzman, L. D.; Iijima, Y.; Jorgenson, J. C.; Matveyeva, N.; Necsoiu, M.; Raynolds, M. K.; Romanovsky, V. E.; Schulla, J.; Tape, K. D.; Walker, D. A.; Wilson, C. J.; Yabuki, H.; Zona, D.

    2016-12-01

    Ice-wedges are common permafrost features formed over hundreds to thousands of years of repeated frost cracking and ice vein growth. We used field and remote sensing observations to assess changes in areas dominated by ice-wedges, and we simulated the effects of those changes on watershed-scale hydrology. We show that top melting of ice-wedges and subsequent ground subsidence has occurred at multiple sites in the North American and Russian Arctic. At most sites, melting ice-wedges have initially resulted in increased wetness contrast across the landscape, evident as increased surface water in the ice-wedge polygon troughs and somewhat drier polygon centers. Most areas are becoming more heterogeneous with wetter troughs, more small ponds (themokarst pits forming initially at ice-wedge intersections and then spreading along the troughs) and drier polygon centers. Some areas with initial good drainage, such as near creeks, lake margins, and in hilly terrain, high-centered polygons form an overall landscape drying due to a drying of both polygon centers and troughs. Unlike the multi-decadal warming observed in permafrost temperatures, the ice-wedge melting that we observed appeared as a sub-decadal response, even at locations with low mean annual permafrost temperatures (down to -14 °C). Gradual long-term air and permafrost warming combined with anomalously warm summers or deep snow winters preceded the onset of the ice-wedge melting. To assess hydrological impacts of ice-wedge melting, we simulated tundra water balance before and after melting. Our coupled hydrological and thermal model experiments applied over hypothetical polygon surfaces suggest that (1) ice-wedge melting that produces a connected trough-network reduces inundation and increases runoff, and that (2) changing patterns of snow distribution due to differential ground subsidence has a major control on ice-wedge polygon tundra water balance despite an identical snow water equivalent at the landscape

  13. Analysis of distribution rule of surface stress on cross wedge rolling contact zone by finite element method

    Science.gov (United States)

    Shu, Xuedao; Li, Lianpeng; Hu, Zhenghuan

    2005-12-01

    Contact surface of cross-wedge rolling is a complicated space surface and distribution rule of contact surface stress is very complicated. So far, its analyzed result was still based on slippery line method. Designing mould and actual production mainly depend on experiential factor. Application and development of cross-wedge rolling was baffled seriously. Based on the forming characteristics of cross-wedge rolling with flat wedge-shape, the ANSYS/DYNA software was developed secondly on the basis of itself, and the corresponding command program was compiled. Rolling process of cross-wedge rolling with flat wedge-shape was simulated successfully. Through simulation, space surface shape of contact surface was achieved, and distribution rule of contact surface stress was analyzed detailed and obtained. The results provide important theoretical foundation for avoiding appearing bug on surface of rolled part, instructing to design cross-wedge mould and confirming force and energy parameter.

  14. Venous catheterization with ultrasound navigation

    Science.gov (United States)

    Kasatkin, A. A.; Urakov, A. L.; Nigmatullina, A. R.

    2015-11-01

    By ultrasound scanning it was determined that respiratory movements made by chest of healthy and sick person are accompanied by respiratory chest rise of internal jugular veins. During the exhalation of an individual diameter of his veins increases and during the breath it decreases down to the complete disappearing if their lumen. Change of the diameter of internal jugular veins in different phases can influence significantly the results of vein puncture and cauterization in patients. The purpose of this research is development of the method increasing the efficiency and safety of cannulation of internal jugular veins by the ultrasound visualization. We suggested the method of catheterization of internal jugular veins by the ultrasound navigation during the execution of which the puncture of venous wall by puncture needle and the following conduction of J-guide is carried out at the moment of patient's exhalation. This method decreases the risk of complications development during catheterization of internal jugular vein due to exclusion of perforating wound of vein and subjacent tissues and anatomical structures.

  15. Venous catheterization with ultrasound navigation

    Energy Technology Data Exchange (ETDEWEB)

    Kasatkin, A. A., E-mail: ant-kasatkin@yandex.ru; Nigmatullina, A. R. [Izhevsk State Medical Academy, Kommunarov street, 281, Izhevsk, Russia, 426034 (Russian Federation); Urakov, A. L., E-mail: ant-kasatkin@yandex.ru [Institute of Mechanics Ural Branch of Russian Academy of Sciences, T.Baramzinoy street 34, Izhevsk, Russia, 426067, Izhevsk (Russian Federation); Izhevsk State Medical Academy, Kommunarov street, 281, Izhevsk, Russia, 426034 (Russian Federation)

    2015-11-17

    By ultrasound scanning it was determined that respiratory movements made by chest of healthy and sick person are accompanied by respiratory chest rise of internal jugular veins. During the exhalation of an individual diameter of his veins increases and during the breath it decreases down to the complete disappearing if their lumen. Change of the diameter of internal jugular veins in different phases can influence significantly the results of vein puncture and cauterization in patients. The purpose of this research is development of the method increasing the efficiency and safety of cannulation of internal jugular veins by the ultrasound visualization. We suggested the method of catheterization of internal jugular veins by the ultrasound navigation during the execution of which the puncture of venous wall by puncture needle and the following conduction of J-guide is carried out at the moment of patient’s exhalation. This method decreases the risk of complications development during catheterization of internal jugular vein due to exclusion of perforating wound of vein and subjacent tissues and anatomical structures.

  16. The Seismic Structure of the Mantle Wedge under Cascade Volcanoes

    Science.gov (United States)

    Levander, A.; Liu, K.; Porritt, R. W.; Allen, R. M.

    2011-12-01

    Under a number of Cascade volcanoes we have identified a characteristic seismic signature in individual station Ps receiver functions and in Ps CCP image volumes made from USArray Transportable Array and Flexible Array stations. In the mantle wedge, the CCP images and the RFs show a strong negative event just below the Moho, paired with a weak to moderate positive event between 50-70 km, and a strong slab event. At most of these volcanoes, a strong negative signal also appears between 15 and 25 km depth in the crust. The signature is particularly clear under Mt. Lassen and Mt. Shasta in data from FAME (Flexible Array Mendocino Experiment), where instruments were close to the volcanic centers. Comparing the average Cascadia volcano signature to those of stations throughout the western U.S. and specifically those of the Cascadia backarc region, shows that this signal is unique to the Cascadia volcanoes. Joint inversion of the Ps receiver functions and ambient noise Rayleigh wave phase velocities (Porritt et al., 2011; Liu et al., submitted) for those volcanoes with the paired events provides 1D shear velocity profiles having common characteristics. A strong sub-Moho low velocity zone from 5 to 15 km thick gives rise to the paired negative-positive signals in the receiver functions. The sub-Moho low velocity zones, with velocities of 3.7 CIDER 2011 summer program.

  17. Precision forming machine with rolling plate cross wedge rolling

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Roller cross wedge rolling(CWR)machines have high rigidity, but sector dies are difficult to process. Plate CWR machines have low rigidity and need large floor space, but plate dies are easy to process. Neither roller CWR machine nor plate CWR machine can produce larger workpieces. Based on the above conclusions, this paper presents the mechanical principle of the precision forming machine with rolling plate CWR. Then, its design principle and machine construction are presented. There are a top press roller above the upper sliding plate and a bottom press roller under the lower sliding plate. The press rollers make rolling contact with the sliding plates. The plate dies are mounted on the upper and lower sliding plates, respectively. Furthermore, the axes of both press rollers and centerline of work-piece always keep in the identical vertical plane during forming process. These make the machine retain advantages of high rigidity for roller CWR machine and simpleness of manufacturing dies for plate CWR machine, and abandon defects of poor rigidity for plate CWR machine and difficulty of manufac-turing dies for roller CWR machine. Moreover, the machine can produce larger workpieces.

  18. Medial opening wedge distal femoral osteotomy for post-traumatic secondary knee osteoarthritis.

    Science.gov (United States)

    Matsui, Gen; Akiyama, Takenori; Ikemura, Satoshi; Mawatari, Taro

    2014-04-30

    Osteoarthritis of the knee secondary to femoral fracture is difficult to treat. There are some surgical options, such as total knee arthroplasty or correction osteotomy. Opening wedge high tibial osteotomy is an established treatment of gonarthrosis. However, few reports are available on the effectiveness of a medial opening wedge distal femoral osteotomy. We present a case of a medial opening wedge distal femoral osteotomy on gonarthrosis secondary to a malunited femoral fracture with varus deformity and leg length discrepancy. This osteotomy was performed at the deformed femur, with locking plate fixation and autologous bone graft. Six months after the surgery, the osteotomy site was filled with bridging callus. Two years later, the Knee Society Score improved from 45 to 90 points. Medial opening wedge distal femoral osteotomy can be a useful method to treat knee osteoarthritis associated with distal femoral deformity.

  19. Development of Cone Wedge Ring Expansion Test to Evaluate Mechanical Properties of Clad Tubing Structure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-10-01

    To determine the hoop tensile properties of irradiated fuel cladding in a hot cell, a cone wedge ring expansion test method was developed. A four-piece wedge insert was designed with tapered angles matched to the cone shape of a loading piston. The ring specimen was expanded in the radial direction by the lateral expansion of the wedges under the downward movement of the piston. The advantages of the proposed method are that implementation of the test setup in a hot cell is simple and easy, and that it enables a direct strain measurement of the test specimen from the piston’s vertical displacement soon after the wedge-clad contact resistance is initiated.

  20. No agreement of mixed venous and central venous saturation in sepsis, independent of sepsis origin

    NARCIS (Netherlands)

    van Beest, Paul A.; van Ingen, Jan; Boerma, E. Christiaan; Holman, Nicole D.; Groen, Henk; Koopmans, Matty; Spronk, Peter E.; Kuiper, Michael A.

    2010-01-01

    Controversy remains regarding the relationship between central venous saturation (ScvO(2)) and mixed venous saturation (SvO(2)) and their use and interchangeability in patients with sepsis or septic shock. We tested the hypothesis that ScvO(2) does not reliably predict SvO(2) in sepsis. Additionally

  1. Femoral venous oxygen saturation is no surrogate for central venous oxygen saturation

    NARCIS (Netherlands)

    van Beest, Paul A.; van der Schors, Alice; Liefers, Henriette; Coenen, Ludo G. J.; Braam, Richard L.; Habib, Najib; Braber, Annemarije; Scheeren, Thomas W. L.; Kuiper, Michael A.; Spronk, Peter E.

    2012-01-01

    Objective:  The purpose of our study was to determine if central venous oxygen saturation and femoral venous oxygen saturation can be used interchangeably during surgery and in critically ill patients. Design:  Prospective observational controlled study. Setting:  Nonacademic university-affiliated

  2. Critical Coulomb Wedge Theory Applied to Hyper-Extended Rifted Margins: A New Perspective

    Science.gov (United States)

    Nirrengarten, M.; Manatschal, G.; Yuan, X.; Kusznir, N. J.; Maillot, B.

    2016-12-01

    Field studies, borehole data and seismic sections show that hyper-extended domains at magma-poor rifted margins: 1) deform predominantly in the brittle field, 2) form wedge shape terminations of the continental crust, and 3) develop a frictional décollement between the hyper-extended crust and the underlying serpentinized mantle. These three observations are also the three requirements to apply the Critical Coulomb Wedge (CCW) theory, which describes the stability limit of a frictional wedge over a décollement. We measure the surface slope and detachment dip of hyper-extended wedges at magma-poor margins to compare them with the stability envelopes of CCW theory. Our analysis shows that lower plate margins, forming the footwall of the major extensional detachment faults, correspond to gravitational wedges. In contrast upper plate margins, forming the hanging wall of major extensional detachment faults, are tectonic extensional wedges. Dip measurements of the lower plate margins cluster on the CCW stability limits, which implies that lower plate wedges have similar shapes and that they are gravitationally stable. Upper plate margins are more complex and are not always at the critical shape due to the evolution of the underlying detachment dip and re-localization of the deformation on new detachment faults. The architecture of hyper-extended wedges results from the interaction between rocks physical properties (frictional parameters and fluid pressures) and the localization of deformation processes. Interpretation of hyper-extended domains with seismic sections is often complex due to thick post-tectonic sediments or salt layers. The application of CCW theory on hyper-extended rifted margins provides a new framework to interpret the fault pattern and its associated sedimentary architecture. In particular the application of CCW theory can explain the formation of extensional allochthons and continentward dipping faults.

  3. Living on the wedge: female control of paternity in a cooperatively polyandrous cichlid

    OpenAIRE

    Kohda, Masanori; Heg, Dik; Makino, Yoshimi; Takeyama, Tomohiro; Shibata, Jun-ya; Watanabe, Katsutoshi; Munehara, Hiroyuki; Hori, Michio; Awata, Satoshi

    2009-01-01

    Theories suggest that, in cooperatively breeding species, female control over paternity and reproductive output may affect male reproductive skew and group stability. Female paternity control may come about through cryptic female choice or female reproductive behaviour, but experimental studies are scarce. Here, we show a new form of female paternity control in a cooperatively polyandrous cichlid fish (Julidochromis transcriptus), in which females prefer wedge-shaped nesting sites. Wedge-shap...

  4. Corneal wedge excision in the treatment of high astigmatism after penetrating keratoplasty.

    Science.gov (United States)

    Ezra, Daniel G; Hay-Smith, Graham; Mearza, Ali; Falcon, Mike G

    2007-08-01

    To report 5 cases of high astigmatism after penetrating keratoplasty (PK) treated with corneal wedge excisions. We report our experience of 5 patients treated with corneal wedge excisions for high astigmatism after PK. A thin sliver of cornea measuring between 0.1 and 0.2 mm in thickness was excised from just inside the graft-recipient interface. The length of the incision centered at the axis of the flatter meridian of the cornea and was extended over a range of 60-90 degrees. The wound was closed with interrupted 10-0 nylon sutures placed every 15 degrees. We also report, for the first time, both pre- and postoperative corneal topography in 3 of our patients who underwent wedge excisions. The mean preoperative astigmatism was 15.2 D (range, 8.5-29.1 D). Postoperatively, after wedge excision, the mean astigmatism was reduced to 2.3 D (range, 1.9-3.7 D). The mean reduction in astigmatism was 12.9 D (range, 6.3-25.4 D). Corneal wedge resection is an effective treatment for high astigmatism after PK. It may prove particularly useful in cases of high astigmatism or where other treatments are not appropriate. We believe that there is still a role for wedge resection as one of many tools to be used in the treatment of high post-PK astigmatism.

  5. [Research on the transmittance spectrum of wedge thin film filter with oblique incidence].

    Science.gov (United States)

    Yu, Kan; Huang, De-Xiu; Yin, Juan-Juan; Bao, Jia-Qi

    2013-08-01

    Angle-tuned thin film filter is widely used in the DWDM system for its broad tunable wavelength range and high rectangular degree. The transmissivity and the half bandwidth is greatly influenced not only by the incident angle, but also by the wedge angle of the non-paralleled thin film filter. In the present paper, the influences of the wedge angle on the transmissivity and the half bandwidth were detailedly analyzed. The proper wedge angle and the orientation can greatly improve the characteristics of the transmittance spectrum. The angle-tuned thin film filter with 0.8 degrees wedge angle was also fabricated. The experimental results show that keeping the wedge angle with the same orientation to the incident angle will worsen the transmissivity and the rectangular degree of the transmittance spectrum. However, keeping the wedge angle orientation reverse to the incident angle will greatly enhance the transmissivity and the rectangular degree of the filter and its tunable wavelength range will broaden by 10 nm.

  6. On the practice of the clinical implementation of enhanced dynamic wedges.

    Science.gov (United States)

    Koken, Phil W; Heukelom, Stan; Cuijpers, Johan P

    2003-01-01

    Practical aspects of the clinical implementation of enhanced dynamic wedges (EDW) replacing manual wedges are presented and discussed extensively. A comparison between measured and calculated data is also presented. Relative dose distributions and wedge factors were calculated with a commercially available treatment planning system and measured in a water-phantom and with an ionization chamber. Wedge factor calculations and measurements were also compared with an independent method of wedge factor calculations available from the literature. Aspects of the clinical implementation, such as safety and quality assurance, were evaluated. Measurements and calculations agreed very well and were slightly better than results of previous studies. Profiles and percentage depth doses (PDDs) agreed within 1% to 1.5% and within 0.5%, respectively. Measured and calculated wedge factors ratios agreed within 0.5% to 1%. Calculated and measured EDW dose distributions showed excellent agreement, both relative and absolute. However, for safe and practical use, specific aspects need to be taken into consideration. Once the treatment planning system is commissioned properly, the clinical implementation of EDW is rather straightforward.

  7. Focusing of surface phonon-polaritons along conical and wedge polar nanostructures

    Science.gov (United States)

    Gluchko, Sergei; Ordonez-Miranda, Jose; Tranchant, Laurent; Antoni, Thomas; Volz, Sebastian

    2015-08-01

    Focusing of surface phonon-polaritons propagating toward the tip of a cone and the edge of a wedge is theoretically analyzed and compared. Based on Maxwell's equations, explicit expressions for the dispersion relations in each structure are determined and solved numerically for a propagation parameter driving the surface phonon-polariton energy density. For conical and wedge structures of SiO2, it is found that: (1) the cone (wedge) supports the polariton focusing only for aperture angles in the interval 18 ° - 68 ° ( 21 ° - 51 ° ), and within the range of excitation frequencies from 32.1 THz (31.5 THz) to 33.9 THz (33.9 THz). In this frequency interval, the real part of the SiO2 permittivity is negative and the presence of polaritons is significant. (2) The polariton focusing efficiency of both the cone and wedge reaches its maximum values at the critical frequency f cr = 33.6 THz and at different aperture angles of about α opt = 45 ° and α opt = 30 ° , respectively. (3) When the polaritons travel from 100 nm to 5 nm toward the tip of the cone with this optimum angle, their Poynting vector increases by a factor of 12, which is about four times larger than the corresponding one provided by the wedge and indicates that the cone is more efficient than the wedge for the focusing of surface phonon-polaritons.

  8. Venous injury in abusive head trauma

    Energy Technology Data Exchange (ETDEWEB)

    Choudhary, Arabinda K. [Nemours A. I. duPont Hospital for Children, Department of Radiology, Wilmington, DE (United States); Bradford, Ray; Thamburaj, K.; Boal, Danielle K.B. [Hershey Medical Center, Department of Radiology, Hershey, PA (United States); Dias, Mark S. [Hershey Medical Center, Department of Neurosurgery, Hershey, PA (United States)

    2015-11-15

    Abusive head trauma (AHT) is an important cause of serious brain injury in infants and young children who have characteristic clinical and imaging findings that are discordant with the clinical history provided. Recent attention has focused on abnormalities of the cranial venous sinuses and cortical veins, both on MRI and at autopsy. Although many have interpreted these to be secondary to the AHT, some have recently argued that these venous abnormalities represent primary cortical sinus and venous thrombosis that leads secondarily to subdural hemorrhage and secondary brain injury. Direct trauma to the veins and sinuses has been reported at autopsy in AHT, but there has been no systematic study of venous abnormalities in cases of AHT. The purpose of this study was to define the incidence and characteristics of venous and sinus abnormalities in AHT. We included all children <36 months of age who were diagnosed with abusive head trauma between 2001 and 2012 and who had MRI and magnetic resonance (MR) venography as part of their diagnostic workup. We analyzed age, gender and clinical findings. MRI and MR venography were analyzed independently by two neuroradiologists with a focus on abnormalities involving the intracranial veins and venous sinuses. A total of 45 children were included. The median age was 3 months (range 15 days to 31 months) and 28 were boys (62%). Clinical findings included retinal hemorrhage in 71% and extracranial fractures in 55%. CT or MRI demonstrated subdural hemorrhage in 41 (91%); none had subdural effusions. In 31 cases (69%) MR venography demonstrated mass effect on the venous sinuses or cortical draining veins, with either displacement or partial or complete effacement of the venous structures from an adjacent subdural hematoma or brain swelling. We also describe the lollipop sign, which represents direct trauma to the cortical bridging veins and was present in 20/45 (44%) children. Evidence of displacement or compression of cortical veins

  9. Poster - Thur Eve - 41: Effect of beam symmetry on enhanced dynamic wedge quality assurance and tolerance levels.

    Science.gov (United States)

    Meyer, T; Hudson, A

    2012-07-01

    Wedged fields are common in three dimensional conformal radiation therapy and require appropriate quality assurance (QA). Currently, our centre calculates the angle of enhanced dynamic wedge (EDW) deliveries with the PROFILER at a monthly frequency but Canadian guidelines on the recommended QA of enhanced dynamic wedges are not available yet. TG-142 recommendations include monthly validation of the central axis wedge factors with only annual verification of wedge profiles. Our monthly QA results have demonstrated a sensitivity of the calculated EDW angle to open beam symmetry. The goal of this work is to compare wedge angle and direct profile comparison as QA measures of EDW delivery and determine appropriate parameter tolerances. The impact of open field symmetry variations on EDW profiles was determined by varying beam symmetry with a test potentiometer and measuring the resulting EDW beam profile with the PROFILER. A calculated wedge angle and direct profile comparison were used to describe the deviations in EDW deliveries. The impact of the deviations on typical plans incorporating wedged fields was evaluated by constructing 'equivalent wedges' to the profile deviations using mixed 60 degree and open field beams and performing plan comparisons in Eclipse. Beam symmetry was observed to have a significant impact on wedge angle for small angle wedges, with a 1% symmetry tolerance allowing a 3.4 degree range of wedge angles for a nominal 10 degree wedge. Direct profile comparison allows a more consistent definition of a dose based tolerance range to be applied without angle dependent tolerances. © 2012 American Association of Physicists in Medicine.

  10. Interactive 3D Analysis of Blood Vessel Trees and Collateral Vessel Volumes in Magnetic Resonance Angiograms in the Mouse Ischemic Hindlimb Model.

    Science.gov (United States)

    Marks, Peter C; Preda, Marilena; Henderson, Terry; Liaw, Lucy; Lindner, Volkhard; Friesel, Robert E; Pinz, Ilka M

    2013-10-31

    The quantitative analysis of blood vessel volumes from magnetic resonance angiograms (MRA) or μCT images is difficult and time-consuming. This fact, when combined with a study that involves multiple scans of multiple subjects, can represent a significant portion of research time. In order to enhance analysis options and to provide an automated and fast analysis method, we developed a software plugin for the ImageJ and Fiji image processing frameworks that enables the quick and reproducible volume quantification of blood vessel segments. The novel plugin named Volume Calculator (VolCal), accepts any binary (thresholded) image and produces a three-dimensional schematic representation of the vasculature that can be directly manipulated by the investigator. Using MRAs of the mouse hindlimb ischemia model, we demonstrate quick and reproducible blood vessel volume calculations with 95 - 98% accuracy. In clinical settings this software may enhance image interpretation and the speed of data analysis and thus enhance intervention decisions for example in peripheral vascular disease or aneurysms. In summary, we provide a novel, fast and interactive quantification of blood vessel volumes for single blood vessels or sets of vessel segments with particular focus on collateral formation after an ischemic insult.

  11. Analysis of Fundus Fluorescein Angiogram Based on the Hessian Matrix of Directional Curvelet Sub-bands and Distance Regularized Level Set Evolution.

    Science.gov (United States)

    Soltanipour, Asieh; Sadri, Saeed; Rabbani, Hossein; Akhlaghi, Mohammad Reza

    2015-01-01

    This paper presents a new procedure for automatic extraction of the blood vessels and optic disk (OD) in fundus fluorescein angiogram (FFA). In order to extract blood vessel centerlines, the algorithm of vessel extraction starts with the analysis of directional images resulting from sub-bands of fast discrete curvelet transform (FDCT) in the similar directions and different scales. For this purpose, each directional image is processed by using information of the first order derivative and eigenvalues obtained from the Hessian matrix. The final vessel segmentation is obtained using a simple region growing algorithm iteratively, which merges centerline images with the contents of images resulting from modified top-hat transform followed by bit plane slicing. After extracting blood vessels from FFA image, candidates regions for OD are enhanced by removing blood vessels from the FFA image, using multi-structure elements morphology, and modification of FDCT coefficients. Then, canny edge detector and Hough transform are applied to the reconstructed image to extract the boundary of candidate regions. At the next step, the information of the main arc of the retinal vessels surrounding the OD region is used to extract the actual location of the OD. Finally, the OD boundary is detected by applying distance regularized level set evolution. The proposed method was tested on the FFA images from angiography unit of Isfahan Feiz Hospital, containing 70 FFA images from different diabetic retinopathy stages. The experimental results show the accuracy more than 93% for vessel segmentation and more than 87% for OD boundary extraction.

  12. Three-dimensional vertebral wedging in mild and moderate adolescent idiopathic scoliosis.

    Directory of Open Access Journals (Sweden)

    Sophie-Anne Scherrer

    Full Text Available BACKGROUND: Vertebral wedging is associated with spinal deformity progression in adolescent idiopathic scoliosis. Reporting frontal and sagittal wedging separately could be misleading since these are projected values of a single three-dimensional deformation of the vertebral body. The objectives of this study were to determine if three-dimensional vertebral body wedging is present in mild scoliosis and if there are a preferential vertebral level, position and plane of deformation with increasing scoliotic severity. METHODOLOGY: Twenty-seven adolescent idiopathic scoliotic girls with mild to moderate Cobb angles (10° to 50° participated in this study. All subjects had at least one set of bi-planar radiographs taken with the EOS® X-ray imaging system prior to any treatment. Subjects were divided into two groups, separating the mild (under 20° from the moderate (20° and over spinal scoliotic deformities. Wedging was calculated in three different geometric planes with respect to the smallest edge of the vertebral body. RESULTS: Factorial analyses of variance revealed a main effect for the scoliosis severity but no main effect of vertebral Levels (apex and each of the three vertebrae above and below it (F = 1.78, p = 0.101. Main effects of vertebral Positions (apex and above or below it (F = 4.20, p = 0.015 and wedging Planes (F = 34.36, p<0.001 were also noted. Post-hoc analysis demonstrated a greater wedging in the inferior group of vertebrae (3.6° than the superior group (2.9°, p = 0.019 and a significantly greater wedging (p≤0.03 along the sagittal plane (4.3°. CONCLUSIONS: Vertebral wedging was present in mild scoliosis and increased as the scoliosis progressed. The greater wedging of the inferior group of vertebrae could be important in estimating the most distal vertebral segment to be restrained by bracing or to be fused in surgery. Largest vertebral body wedging values obtained in the sagittal plane support

  13. The Essentials of Parathyroid Hormone Venous Sampling

    Energy Technology Data Exchange (ETDEWEB)

    Taslakian, Bedros, E-mail: btaslakian@gmail.com [NYU Langone Medical Center, Department of Radiology, NYU School of Medicine (United States); Trerotola, Scott O., E-mail: streroto@uphs.upenn.edu [Perelman School of Medicine of the University of Pennsylvania, Department of Radiology (United States); Sacks, Barry, E-mail: bsacks@bidmc.harvard.edu [Beth Israel Deaconess Medical Center, Department of Interventional Radiology (United States); Oklu, Rahmi, E-mail: oklu.rahmi@mayo.edu [Mayo Clinic, Department of Interventional Radiology (United States); Deipolyi, Amy, E-mail: deipolya@mskcc.org [Memorial Sloan Kettering Cancer Center, Department of Radiology (United States)

    2017-01-15

    Hyperparathyroidism is an excess of parathyroid hormone in the blood due to over-activity of one or more parathyroid gland. Localization of abnormal glands with noninvasive imaging modalities, such as technetium sestamibi scan and cross-sectional imaging, has a high success rate. Parathyroid venous sampling is performed for patients with persistent or recurrent disease after previous parathyroid surgery, when repeat noninvasive imaging studies are negative or discordant. The success of invasive localization studies and results interpretation is dependent on the interventional radiologist’s understanding of the normal and ectopic anatomic locations of parathyroid glands, as well as their blood supply and venous drainage. Anatomic and technical considerations for selective parathyroid venous sampling are reviewed.

  14. Central Venous Catheter-Related Hydrothorax

    Directory of Open Access Journals (Sweden)

    Se Hun Kim

    2015-11-01

    Full Text Available This report describes a case of 88-year-old women who developed central venous catheter-related bilateral hydrothorax, in which left pleural effusion, while right pleural effusion was being drained. The drainage prevented accumulation of fluid in the right pleural space, indicating that there was neither extravasation of infusion fluid nor connection between the two pleural cavities. The only explanation for bilateral hydrothorax in this case is lymphatic connections. Although vascular injuries by central venous catheter can cause catheter-related hydrothorax, it is most likely that the positioning of the tip of central venous catheter within the lymphatic duct opening in the right sub-clavian-jugular confluence or superior vena cava causes the catheter-related hydrothorax. Pericardial effusion can also result from retrograde lymphatic flow through the pulmonary lymphatic chains.

  15. Noninvasive measurement of central venous pressure

    Science.gov (United States)

    Webster, J. G.; Mastenbrook, S. M., Jr.

    1972-01-01

    A technique for the noninvasive measurement of CVP in man was developed. The method involves monitoring venous velocity at a point in the periphery with a transcutaneous Doppler ultrasonic velocity meter while the patient performs a forced expiratory maneuver. The idea is the CVP is related to the value of pressure measured at the mouth which just stops the flow in the vein. Two improvements were made over the original procedure. First, the site of venous velocity measurement was shifted from a vein at the antecubital fossa (elbow) to the right external jugular vein in the neck. This allows for sensing more readily events occurring in the central veins. Secondly, and perhaps most significantly, a procedure for obtaining a curve of relative mean venous velocity vs mouth pressure was developed.

  16. Complications of central venous stenosis due to permanent central venous catheters in children on hemodialysis.

    Science.gov (United States)

    Rinat, Choni; Ben-Shalom, Efrat; Becker-Cohen, Rachel; Feinstein, Sofia; Frishberg, Yaacov

    2014-11-01

    Central venous catheters are frequently used as access for hemodialysis (HD) in children. One of the known complications is central venous stenosis. Although this complication is not rare, it is often asymptomatic and therefore unacknowledged. Superior vena cava (SVC) stenosis is obviously suspected in the presence of upper body edema, but several other signs and symptoms are often unrecognized as being part of this syndrome. We describe four patients with various manifestations of central venous stenosis and SVC syndrome. These sometimes life- or organ-threatening conditions include obstructive sleep apnea, unresolving stridor, increased intracranial pressure, increased intraocular pressure, right-sided pleural effusion, protein-losing enteropathy and lymphadenopathy. The temporal relationship of these complications associated with the use of central venous catheters and documentation of venous stenosis, together with their resolution after alleviation of high venous pressure, points to a causal role. We suggest pathophysiological mechanisms for the formation of each of these complications. In patients with occlusion of the SVC, various unexpected clinical entities can be caused by high central venous pressure. As often the etiology is not obvious, a high index of suspicion is needed as in some cases prompt alleviation of the high pressure is mandatory.

  17. Clinical features and diagnosis of venous thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Hirsh, J.; Hull, R.D.; Raskob, G.E.

    1986-12-01

    The clinical diagnosis of venous thrombosis is inaccurate because the clinical findings are both insensitive and nonspecific. The sensitivity of clinical diagnosis is low because many potentially dangerous venous thrombi are clinically silent. The specificity of clinical diagnosis is low because the symptoms or signs of venous thrombosis all can be caused by nonthrombotic disorders. A current approach to the diagnosis of clinically suspected venous thrombosis favors the use of impedance plethysmography over Doppler ultrasonography as the main test for this disorder. This is because impedance plethysmography is precise and objective, whereas the interpretation of Doppler ultrasonography is subjective and requires considerable skill and experience to form reliable diagnoses. The use of serial impedance plethysmography has been evaluated recently in a prospective study. The rationale of repeated impedance plethysmography evaluation is based on the premise that calf vein thrombi are only clinically important when they extend into the proximal veins, at which point detection with impedance plethysmography is possible. Therefore, by performing repeated examinations with impedance plethysmography in patients with clinically suspected venous thrombosis, it is possible to identify patients with extending calf vein thrombosis who can be treated appropriately. Impedance plethysmography is performed immediately on referral; if it is positive in the absence of clinical conditions that are known to produce falsely positive results, the diagnosis of venous thrombosis is established, and the patient is treated accordingly. If the result of the initial impedance plethysmography evaluation is negative, anticoagulant therapy is withheld, and impedance plethysmography is repeated the following day, again on day 5 to 7 and on day 10 to 14. 87 references.

  18. Admission Hyperglycemia and Clinical Outcome in Cerebral Venous Thrombosis

    NARCIS (Netherlands)

    Zuurbier, Susanna M.; Hiltunen, Sini; Tatlisumak, Turgut; Peters, Guusje M.; Silvis, Suzanne M.; Haapaniemi, Elena; Kruyt, Nyika D.; Putaala, Jukka; Coutinho, Jonathan M.

    2016-01-01

    Background and Purpose-Admission hyperglycemia is associated with poor clinical outcome in ischemic and hemorrhagic stroke. Admission hyperglycemia has not been investigated in patients with cerebral venous thrombosis. Methods-Consecutive adult patients with cerebral venous thrombosis were included

  19. Massive hemoptysis and deep venous thrombosis presenting in a woman with Hughes-Stovin syndrome: a case report

    Directory of Open Access Journals (Sweden)

    Al-Jahdali Hamdan

    2010-04-01

    Full Text Available Abstract Introduction Hughes-Stovin syndrome is a very rare disease with fewer than 30 cases reported in the literature. The disease is thought to be a variant of Behcet's disease and is defined by the presence of pulmonary artery aneurysm in association with peripheral venous thrombosis. Case presentation A previously healthy 23-year-old Saudi woman presented with massive hemoptysis a day prior to her admission to our hospital. She had a six-month history of recurrent fever, cough, dyspnea, and recurrent oral ulceration. Contrast-enhanced computed tomography scan of her chest and pulmonary angiogram demonstrated a single right-lower lobe pulmonary artery aneurysm. She underwent thoracotomy and right lower lobe resection. Her postoperative course was complicated by deep vein thrombosis. She also developed headache and papilledema, while a magnetic resonance imaging of her brain suggested vasculitis. Based on these clinical presentations, she was diagnosed and treated with Hughes-Stovin syndrome. Conclusion The majority of cases of Hughes-Stovin syndrome are reported among men, with only two cases occurring in women. A case of Hughes-Stovin syndrome occurring in a woman is presented in this report. She was treated successfully with multimodality treatment that includes surgery, steroids and cytotoxic agents.

  20. Venous thrombosis: the history of knowledge.

    Science.gov (United States)

    Mannucci, P M

    2002-01-01

    Venous thrombosis is a frequent disease. It is surprising, therefore, that no case truly compatible with a diagnosis of venous thrombosis was apparently reported in the antiquity. There is no case that could be reasonably attributed to a venous thrombus in the writings of Hippocrates, Galenus, Celius Aurelianus, Ibn an-Nafiz, Avicenna and others. Venous thrombosis is not among the many diseases mentioned in the Bible. The term "leucophlegmasia", first used by Hippocrates and then by Celius Aurelianus, refers to cases of bilateral leg edema, most likely due to conditions such as heart failure, liver cirrhosis and renal insufficiency. Nothing compatible with a diagnosis of venous thrombosis can be found in pieces of art from ancient Egypt, Greece, Rome, Persia and South America. While in these sources there are sometimes representations of varicose veins and ulcers, unilateral leg edema or other pictures compatible with venous thrombosis are not featured. The first well documented case of venous thrombosis is depicted in a beautifully illustrated manuscript written in the 13th century and currently preserved in Paris at the Bibliothèque Nationale (MS Fr 2829, Folio 87). The manuscript describes the case of a young man from Normandy named Raoul who at the age of twenty developed unilateral edema in the right ankle that subsequently extended up to the thigh, with no obvious symptoms in the contralateral leg. Raoul was advised to visit the tomb of Saint Louis who was buried in the church of Saint Denis, where the patient spent several days confessing his sins and praying the saint. Afterwards he chose to collect the dust accumulating below the stone that covered the tomb and to apply it on the fistulae and ulcers of his foot. The openings stopped running and were filled with flesh. He was first obliged to use crutches but subsequently he could walk with a cane, to be eventually able to dispose of all devices, even though his foot throbbed a little. Raoul was cured as

  1. Management of Peripheral and Truncal Venous Injuries

    Directory of Open Access Journals (Sweden)

    Triantafillos G. Giannakopoulos

    2017-08-01

    Full Text Available Civilian injuries are increasing according to the World Health Organization, and this is attributed mainly to road traffic accidents and urban interpersonal violence. Vascular injuries are common in these scenarios and are associated with high morbidity and mortality rates. Associated peripheral venous trauma is less likely to lead to death and controversy remains whether ligation or repair should be the primary approach. Conversely, non-compressible truncal venous insult can be lethal due to exsanguination, thus a high index of suspicion is crucial. Operative management is demanding with fair results but recent endovascular adjuncts demonstrate promising results and seem to be the way forward for these serious conditions.

  2. Jugular Venous Catheterization: A Case of Knotting

    Directory of Open Access Journals (Sweden)

    E. Erkılıç

    2015-01-01

    Full Text Available A 79-year-old woman, diagnosed for cancer of the ovary, had a central catheter that was placed with difficulty through the right internal jugular vein intraoperatively. After oophorectomy, it was realized that the catheter was knotted. Thus, the central venous catheter was removed successfully using a traction technique in the operating room. Central venous catheter use may result in various complications, although it has been used as an invasive method for hemodynamic monitoring and fluid and drug infusion. Here, we present catheter knotting in a case with solutions for this complication, under literature review.

  3. Venous capacity, venous refill time and the effectiveness of the calf muscle pump in normal subjects.

    Science.gov (United States)

    Barendsen, G J; van den Berg, J W

    1984-03-01

    With strain gauge plethysmography various procedures to assess the competence of the venous system in the lower leg were compared in 10 normal subjects. The reproducibility and ease of use were established, and normal values were obtained. It is concluded, that measurements in the sitting position are preferable to those in the standing position. To measure the venous capacity, the dependency test is the method of choice. Rhythmic exercise to assess the effectiveness of the calf muscle pump can be restricted to five successive contractions. The refill time after exercise is not a suitable parameter to assess the competence of the venous valves.

  4. Human cerebral venous outflow pathway depends on posture and central venous pressure

    DEFF Research Database (Denmark)

    Gisolf, J; van Lieshout, J J; van Heusden, K

    2004-01-01

    Internal jugular veins are the major cerebral venous outflow pathway in supine humans. In upright humans the positioning of these veins above heart level causes them to collapse. An alternative cerebral outflow pathway is the vertebral venous plexus. We set out to determine the effect of posture...... and during a Valsalva manoeuvre in both body positions, correlate highly with model simulation of the jugular cross-sectional area (R(2) = 0.97). The results suggest that the cerebral venous flow distribution depends on posture and CVP: in supine humans the internal jugular veins are the primary pathway...

  5. The effect of shoe design and lateral wedges on knee load and neuromuscular control in healthy subjects during walking

    DEFF Research Database (Denmark)

    Mølgaard, Carsten; Kersting, Uwe G.

    2014-01-01

    design/type on the effectiveness of lateral wedging has not been investigated so far. The Purpose of the present study was to explore alterations in knee loading due to lateral foot wedges in three different shoes. Methods: Thirteen healthy participants with no history of knee pain were tested using...... wedging is effective regardless of shoe design. Differences between the three neutral walking conditions underline the importance of footwear choice in individuals. It is safe to apply lateral wedges without jeopardising muscular control during walking regardless of shoe type. Possible effects of altering...... three-dimensional gait analysis. Barefoot walking, walking in a running shoe, an Oxford-type leather shoe, and a rocker shoe were analysed. The shoes were tested both with and without a 10-degree full-length laterally wedged insole. Results: There were significant shoe wedge interactions on the first...

  6. Laser-based linear and nonlinear guided elastic waves at surfaces (2D) and wedges (1D).

    Science.gov (United States)

    Hess, Peter; Lomonosov, Alexey M; Mayer, Andreas P

    2014-01-01

    The characteristic features and applications of linear and nonlinear guided elastic waves propagating along surfaces (2D) and wedges (1D) are discussed. Laser-based excitation, detection, or contact-free analysis of these guided waves with pump-probe methods are reviewed. Determination of material parameters by broadband surface acoustic waves (SAWs) and other applications in nondestructive evaluation (NDE) are considered. The realization of nonlinear SAWs in the form of solitary waves and as shock waves, used for the determination of the fracture strength, is described. The unique properties of dispersion-free wedge waves (WWs) propagating along homogeneous wedges and of dispersive wedge waves observed in the presence of wedge modifications such as tip truncation or coatings are outlined. Theoretical and experimental results on nonlinear wedge waves in isotropic and anisotropic solids are presented. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Patterns of cranial venous system from the comparative anatomy in vertebrates. Part I, introduction and the dorsal venous system.

    Science.gov (United States)

    Aurboonyawat, T; Suthipongchai, S; Pereira, V; Ozanne, A; Lasjaunias, P

    2007-12-01

    Many classifications of the cerebral venous system are found in the literature but they are seldom based on phylogenic study. Among vertebrates, venous drainage of the brain vesicles differs depending on the species. Due to the variability, poorly descriptive articles, and many different names used for the veins, the comparative study of the cranial venous system can hardly be performed in detail. The cranial venous system in vertebrates can be divided into three systems based on the evolution of the meninges and structures of the brain vesicles: the dorsal, lateral-ventral and ventricular systems. This study proposes a new classification of the venous drainage of brain vesicles using knowledge from a comparative study of vertebrates and focusing on the dorsal venous system. We found that the venous drainage of the neopallium and neocerebellum is involved with this system which may be a recent acquisition of cranial venous evolution.

  8. Misplaced left internal jugular venous catheter with an exceptional ...

    African Journals Online (AJOL)

    Large numbers of central venous catheters (CVCs) are placed each year in the intensive care units and misplacement occurs frequently. Many critically ill patients require central venous catheterization for multiple and varied reasons. Internal jugular vein (IJV) catheter is one of the most frequent central venous catheters in ...

  9. Mechanochemical endovenous ablation and new frontiers in venous intervention

    NARCIS (Netherlands)

    Boersma, D

    2017-01-01

    Venous insufficiency of the lower extremities is a common condition and related to various symptoms, including venous ulcers. The effect of venous insufficiency on patients’ health-related quality of life is substantial and comparable with other chronic diseases such as arthritis, diabetes, and

  10. [Etiology, nomenclature and pathophysiology of chronic venous insufficiency].

    Science.gov (United States)

    Salmhofer, W

    2016-06-01

    This article presents current notions and conceptions of the aetiopathogenesis of primary varicosis and chronic venous insufficiency, as well as an updated version of the nomenclature and terminology of venous disorders, which was recently agreed on in an international consensus conference. Furthermore, both CEAP-classification and venous severity score system are discussed.

  11. The recalcitrant venous leg ulcer - A never ending story?

    NARCIS (Netherlands)

    S.W.I. Reeder (Suzan); M.B. Maessen-Visch (Birgitte); S.I. Langendoen; K.P. de Roos; H.A.M. Neumann (Martino)

    2013-01-01

    textabstractIntroduction: In general, four particular causes of recalcitrant venous leg ulcers may be distinguished. These are foot pump insufficiency, chronic venous compartment syndrome and non-re-canalized popliteal vein thrombosis. The fourth cause of recalcitrant venous leg ulcers is

  12. Total Anomalous Pulmonary Venous Connection: Preoperative Anatomy, Physiology, Imaging, and Interventional Management of Postoperative Pulmonary Venous Obstruction.

    Science.gov (United States)

    Files, Matthew D; Morray, Brian

    2017-06-01

    Total anomalous pulmonary venous connection refers to a spectrum of cardiac anomalies where the pulmonary veins fail to return to the left atrium and the pulmonary venous blood returns through a systemic vein or directly to the right atrium. There is a wide anatomical variety of venous connections and degrees of pulmonary venous obstruction that affect the presentation, surgical repair, and outcomes. In this review, we explore the preoperative physiology, echocardiographic diagnosis, and approach to postoperative complications.

  13. Wedge and spring assembly for securing coils in electromagnets and dynamoelectric machines

    Science.gov (United States)

    Lindner, M.; Cottingham, J.G.

    1996-03-12

    A wedge and spring assembly for use in electromagnets or dynamoelectric machines is disclosed having a housing with an axis therethrough and a plurality of coils supported on salient poles that extend radially inward from the housing toward the housing axis to define a plurality of interpole spaces. The wedge and spring assembly includes a nonmagnetic retainer spring and a nonmagnetic wedge. The retainer spring is formed to fit into one of the interpole spaces, and has juxtaposed ends defining between them a slit extending in a direction generally parallel to the housing axis. The wedge for insertion into the slit provides an outwardly directed force on respective portions of the juxtaposed ends to expand the slit so that respective portions of the retainer spring engage areas of the coils adjacent thereto, thereby resiliently holding the coils against their respective salient poles. The retainer spring is generally triangular shaped to fit within the interpole space, and the wedge is generally T-shaped. 6 figs.

  14. Inactivation of Listeria monocytogenes using Water Bath Heat Treatment in Vacuum Packed Ricotta Salata Cheese Wedges.

    Science.gov (United States)

    Spanu, Carlo; Scarano, Christian; Spanu, Vincenzo; Pala, Carlo; Di Salvo, Riccardo; Piga, Carlo; Ullu, Antonio; Casti, Daniele; Lamon, Sonia; Cossu, Francesca; Ibba, Michela; De Santis, Enrico Pietro Luigi

    2015-07-01

    Ricotta salata cheese is frequently contaminated on the surface with Listeria monocytogenes. Water bath heat treatment in vacuum packed whole ricotta salata cheese wheels demonstrated to be effective in inactivating L. monocytogenes. However, the risk of cross-contamination in ricotta salata wedges is increased during cheese cutting. Therefore, the effectiveness of heat treatment in ricotta salata wedges has to be demonstrated conducting a new validation study. In this study, 9 different time temperature combinations, 75, 85, and 90 °C applied for 10, 20, and 30 min each, were tested on artificially contaminated ricotta salata cheese wedges. The extent of the lethal effect on L. monocytogenes was assessed 1 and 30 d after the application of the hot water bath treatment. Five of 9 combinations, 75 °C for 30 min, 85 °C for 20, and 30 min, and 90°C for 20 and 30 min, demonstrated to meet the process criteria of at least 5 log reduction. Sensory analyses were also conducted in order to account for the potential impact on sensory features of ricotta salata wedges, which showed no significant differences between treatments. This study allowed to select water bath heat treatments of vacuum packed ricotta salata wedges effective to reduce L. monocytogenes contamination. Such treatments can be successfully applied by food business operator to meet compliance with microbiological criteria through the designated shelf-life. © 2015 Institute of Food Technologists®

  15. Slamming pressures on the bottom of a free-falling vertical wedge

    Science.gov (United States)

    Ikeda, C. M.; Judge, C. Q.

    2013-11-01

    High-speed planing boats are subjected to repeat impacts due to slamming, which can cause structural damage and injury to passengers. A first step in understanding and predicting the physics of a craft re-entering the water after becoming partially airborne is an experimental vertical drop test of a prismastic wedge (deadrise angle, β =20° beam, B = 300 mm; and length, L = 600 mm). The acrylic wedge was mounted to a rig allowing it to free-fall into a deep-water tank (5.2m × 5.2m × 4.2m deep) from heights 0 keel to the free surface. The wedge was instrumented to record vertical position, acceleration, and pressure on the bottom surface. A pressure mapping system, capable of measuring several points over the area of the thin (0.1 mm) film sensor at sampling rates up to 20 kHz, is used and compared to surface-mounted pressure transducers (sampled at 10 kHz). A high speed camera (1000 fps, resolution of 1920 × 1200 pixels) is mounted above the wedge model to record the wetted surface as the wedge descended below the free surface. The pressure measurements taken with both conventional surface pressure transducers and the pressure mapping system agree within 10% of the peak pressure values (0.7 bar, typical). Supported by the Office of Naval Research.

  16. Apixaban for Extended Treatment of Venous Thromboembolism

    NARCIS (Netherlands)

    Agnelli, Giancarlo; Buller, Harry R.; Cohen, Alexander; Curto, Madelyn; Gallus, Alexander S.; Johnson, Margot; Porcari, Anthony; Raskob, Gary E.; Weitz, Jeffrey I.; Gallus, Alexander; Raskob, Gary; Weitz, Jeffrey; Prins, Martin; Brandjes, Dees; Kolbach, Dinanda; Limburg, Martinus; Mac Gillavry, Melvin; Otten, Johannes Martinus; Peters, Ron; Roos, Yvo; Segers, Annelise; Slagboom, Ton; Bounameaux, Henry; Hirsh, Jack; Samama, Meyer Michel; Wedel, Hans; Masiukiewicz, Urszula; Pak, Raphael; Sanders, Paul; Sisson, Melanie; Sullivan, Beth; Thompson, John; Auerbach, Jennifer; Cesario, Lynne; Gamero, Miguel; Gordon, Margot; Griffiths, Angela; Noble, Melanie; Ott, Jana; Pennington, Ann; Peffer, Allison; Reinhold, Peggy; Simmons, Melanie; Urwin, Keri; Ceresetto, Jose; McRae, Simon; Pabinger, Ingrid; Pereira, Adamastor Humberto; Spencer, Fred; Gorican, Karel; Husted, Steen Elkiaer; Mottier, Dominique; Harenberg, Job; Pinjala, Ramakrishna; Zeltser, David; Imberti, Davide; Sandset, Morten; Torbicki, Adam; Fijalkowska, Anna; Albino, Jose Pereira; Kirienko, Alexander; Shvarts, Yury; Monreal, Manuel; Jacobson, Barry; Dolan, Gerry; Gudz, Ivan; Ortel, Tom; Spyropoulos, Alex; Torbicki, A.; Fijalkowska, A.; Skupyy, O.; Beryer-Westendorf, J.; de Pellegrin, A.; Prasol, V.; Schellong, S.; Jacobson, B.; Falvo, N.; Abramov, I.; Cizek, V.; Husted, S.; Desai, S.; Gudz, I.; Barillari, G.; Sergeev, O.; Chetter, I.; Inbal, A.; McCollum, C.; Shvalb, P.; Torp-Pedersen, C.; Vasylyuk, S.; Kraemmer Nielsen, H.; Pernod, G.; Schmidt, J.; Bova, C.; Gerasymov, V.; Pabinger-Fasching, I.; Skalicka, L.; Zaichuk, A.; Achkar, A.; Bremmelgaard, A.; Chochola, J.; Gould, T.; Khalafallah, A.; Jakobsen, T.; Rose, P.; Zhukov, B.; Dedek, V.; Mirete Ferrer, J.; Pesant, Y.; Repin, A.; Salem, H.; Solis Morales, L.; Spacek, R.; Cannon, K.; Grzelakowski, P.; Jindal, R.; Pereira, A.; Zidkova, E.; Ambrosio, G.; Cardozo, M.; Dunaj, M.; Gallus, A.; Gavish, D.; Ghanima, W.; Harenberg, J.; Leduc, J. J.; Mismetti, P.; Panico, M.; Porreca, E.; Riera, A.; Bareford, D.; Chong, B.; Dvoryashina, I.; Gómez Cerezo, J.; Kobza, I.; Nielsen, T.; Pendleton, R.; Pullman, J.; Schiffman, G.; Stanbro, M.; Zwettler, U.; Aquilanti, S.; Bratsch, H.; Cohen, K.; Elias, D.; Gan, E.; Holaj, R.; Klinke, W.; Liu, H. S. Y.; Sandset, P. M.; van Nieuwenhuizen, E.; Álvarez-Sala, L. A.; Basson, M.; Braester, A.; Bura-Riviere, A.; Calvo Vargas, C.; Cohen, A.; Correa, J.; Elias, M.; Frost, L.; Imberti, D.; Landolfi, R.; Marschang, P.; Moreira, R.; Mottier, D.; Natarajan, S.; Pottier, P.; Tosetto, A.; Tuxen, C.; Vöhringer, H. F.; Alexander, A.; Barbarash, O.; Fajardo Campos, P.; Graham, M.; Gubka, O.; Hudcovic, M.; Hussein, O.; Jackson, D.; Katelnitskiy, I.; Lawall, H.; Monreal, M.; Palareti, G.; Poggio, R.; Roos, J.; Simonneau, G.; Smith, S. W.; Szopinski, P.; Ortel, T.; Zimlichman, R.; Bridgers, D.; Colan, D.; Czekalski, P.; de Jong, D.; Fortinez, J. T.; Garcia Bragado, F.; Harrington, D.; Izbicki, G.; Kadr, H.; Koslow, A.; Loftus, I.; Marais, H.; Neumeister, A.; Oliven, A.; Palla, A.; Pop, C.; Prandoni, P.; Puskas, A.; Sanchez Llamas, F.; Shotan, A.; Shvarts, Y.; Singh, P.; Tveit, A.; Baker, R.; Borja, V.; Brenner, B.; Brown, H.; Ceresetto, J.; Cha, T. J.; Cohen, Y.; D'Angelo, A.; Dhar, A.; Friis, E.; Hueur, H.; Jiménez Rodríguez Madridejos, R.; Karl, J.; Karrasch, J.; Lishner, M.; Manenti, E.; McRae, S.; Meneveau, N.; Nguyen, D.; Sanchez-Escalante, L.; Santoscoy Ibarra, J.; Sokurenko, G.; Staroverov, I.; Stein, R.; Abdullah, I.; Agnelli, G.; Alcocer Gamba, M.; Balanda, J.; Bruckner, I.; Calabuig Alborch, J.; Caraco, Y.; Comerota, A.; Cromer, M.; de Araujo Filho, J.; de los Rios Ibarra, M.; Diaz-Castañon, J.; Doshi, A.; Ebrahim, I.; Fessel, W. J.; Fletcher, E.; Fourie, N.; Fu, C.; Gutowski, P.; Haddad, G.; Hoffman, U.; Jardula, M.; Kvasnicka, T.; Lewczuk, J.; Leyden, M.; Livneh, A.; Lodigiani, C.; Lovell, C.; Miekus, P.; Paloma, M. J.; Parakh, R.; Raval, M.; Schmidt-Lucke, J.; Shtutin, O.; Soroka, V.; Stevens, D.; Sulik, P.; Tay, J. C.; Vejby-Christensen, H.; Vinereanu, D.; Baghestanian, M.; Bono, J.; Cerana, S.; Freire, A.; Gibson, K.; Giumelli, C.; Iastrebner, C.; Karpenko, A.; Kelly, A.; Lacroix, P.; LaFata, J.; Lobo, S.; Macik, B. G.; Marchena Yglesias, P.; Nishinari, K.; Pinjala, R.; Podczeck-Schweighofer, A.; Raby, K.; Sirpal, S.; Solymoss, S.; Spencer, F.; van Zyl, L.; Vargas Núñez, J. A.; von Bilderling, P.; Warr, T.; Wronski, J.; Wurster, M.; Albino, J. A.; Albuquerque, L.; Averill, F.; Baek, S. H.; Bello, F.; Bergoeing, M.; Blanc, F. X.; Bloomberg, R.; Bolster, D.; Brockmyre, A.; Calimano, C.; Checketts, D.; Cieplinski, W.; Chervu, A.; Collado, F.; Denaro, C.; Gaciong, Z.; Game, M.; Iskander, A.; Kaatz, S.; Kim, D. I.; Koura, F.; Laguna, F.; Lanas Zanetti, F.; Lindhoff-Last, E.; Melaniuk, M.; Meade, A.; Murphy, T.; Ng, H. J.; Páramo Fernández, J. A.; Patil, C.; Piovella, F.; Prisco, D.; Pruszczyk, P.; Reimers, G.; Rivera, E.; Rodriguez-Cintron, W.; Rosenthal, S.; Salbach, P.; Salvador, D.; Schuller, D.; Siragusa, S.; Staniszewski, R.; Torp, R.; Vora, K.; Yip, G.; Alfieri, A.; Belaji, V.; Bhagavan, N.; Carnovali, M.; Cobos Segarra, J.; Di Todaro, F.; Dowell, A.; Corder, C.; Crispin, P.; Cuadrado, J.; Flippo, G.; Fraiz, J.; Guillaumon, A.; Gvora, T.; Hakki, S.; Harris, L.; Ison, R.; Htun, P. T.; Jasani, R.; Kates, M.; Kaminski, L.; Kamerkar, D.; Kirienko, A.; Kroger, K.; LaPerna, L.; Leiva, J.; Luber, J.; McCann, A.; McKenzie, W.; Menna Barreto, S.; Moran, J.; Nikulnikov, P.; Paliwal, Y.; Patel, M.; Pilger, E.; Renwick, W.; Shevela, A.; Starosiliz, D.; Stringam, S.; Spyropoulos, A.; To, R.; Updegrove, J.; van Bellen, B.; Waintrub, M.; White, J.; Yeo, E.; Zangroniz, P.; Zeltser, D.

    2013-01-01

    BACKGROUND Apixaban, an oral factor Xa inhibitor that can be administered in a simple, fixed-dose regimen, may be an option for the extended treatment of venous thromboembolism. METHODS In this randomized, double-blind study, we compared two doses of apixaban (2.5 mg and 5 mg, twice daily) with

  17. Travel and venous thrombosis: a systematic review

    NARCIS (Netherlands)

    Kuipers, S.; Schreijer, A. J. M.; Cannegieter, S. C.; Bueller, H. R.; Rosendaal, F. R.; Middeldorp, S.

    2007-01-01

    In the past decade, numerous publications on the association between venous thrombosis (VT) and travel have been published. Relative and absolute risks of VT after travel, and particularly after travel by air, have been studied in case-control and observational follow-up studies, whereas the effect

  18. The aetiology of deep venous thrombosis.

    Science.gov (United States)

    Malone, P C; Agutter, P S

    2006-09-01

    Most ideas about the pathogenesis of deep venous thrombosis (DVT) are dominated by a 'consensus model' first articulated around 1962. This model invokes 'Virchow's triad' and attributes thrombogenesis in veins to some combination of 'hypercoagulability', 'stasis' and 'intimal injury'. This arose as a by-product of studies on the mechanisms of haemostasis and bleeding diatheses that were at best only indirectly relevant to thrombosis, and there are reasons for doubting the causal significance of 'hypercoagulability' and 'stasis' in the aetiology of DVT. Proponents of the consensus model make little reference to a substantial literature, mostly historical, that: (a) emphasizes the significance of the venous valve pockets (VVP) and blood rheology in DVT pathogenesis; and (b) describes morphological features specific to venous thrombi that a valid aetiological model must explain. This literature provides the basis for an alternative hypothesis of DVT aetiology, published some 30 years ago, which has been experimentally corroborated and is compatible with recent cell and molecular biological studies of the venous endothelium. We review this alternative hypothesis, considering its potential value for future research on DVT and embolism, and its significance for clinical practice.

  19. Thermodilution-determined Internal Jugular Venous Flow

    DEFF Research Database (Denmark)

    Rasmussen, Peter; Widmer, Mario; Hilty, Matthias P

    2017-01-01

    PURPOSE: Cerebral blood flow (CBF) increases ~20% during whole body exercise although a Kety-Schmidt-determined CBF is reported to remain stable; a discrepancy that could reflect evaluation of arterial vs. internal jugular venous (IJV) flow and/or that CBF is influenced by posture. Here we test...

  20. Venous thromboembolism: Risk profile and management of ...

    African Journals Online (AJOL)

    Objectives. This study aims to describe the venous thromboembolism (VTE) risk profile of women undergoing elective gynaecological surgery in a tertiary hospital and to audit the VTE prophylaxis prescribed. Methods. One hundred and nine women who underwent elective gynaecological surgery at Kalafong Provincial ...

  1. Clinical overview of venous thromboembolism | Schellack | South ...

    African Journals Online (AJOL)

    Venous thromboembolism (VTE) encompasses two vascular conditions that are of significant importance, namely deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT is also the most common cause of PE. Medical and surgical patients, and individuals who are at increased risk of developing VTE through a ...

  2. Venous thromboembolism: awareness and practice of ...

    African Journals Online (AJOL)

    However, the high level of thromboprophylaxis practice appears doubtful because only a few of these physicians carry out VTE risk assessment for their patients as well as follow clinical guidelines on VTE thromboprophylaxis. Key words: Venous thromboembolism, deep vein thrombosis, pulmonary embolism, risk factor, ...

  3. Venous function after pharmacomechanical thrombolysis for ...

    African Journals Online (AJOL)

    Venous function after pharmacomechanical thrombolysis for extensive iliofemoral deep vein thrombosis. ... The PDF file you selected should load here if your Web browser has a PDF reader plug-in installed (for example, a recent version of Adobe Acrobat Reader). If you would like more information about how to print, save, ...

  4. Urethro-venous intravasation during urethrography

    African Journals Online (AJOL)

    J.M. Ratkal

    Abstract. Retrograde urethrography is a procedure used to evaluate urethral strictures. Urethro-venous intravasation, rarely seen during retrograde urethrography, can result in bacteremia, adverse reactions to contrast agents, renal failure and even pulmonary embolism. We report one such case of a male patient who ...

  5. Central venous pressure monitoring in clinical practice.

    Science.gov (United States)

    Scales, Katie

    This article provides an overview of central venous pressure (CVP) monitoring in clinical practice. It explores the underpinning anatomy and physiology, as well as the indications and means of access, for the procedure. The mechanics and practicalities of measuring CVP are discussed and information for troubleshooting is provided.

  6. Pediatric central venous access devices: nursing interventions

    Directory of Open Access Journals (Sweden)

    Duffy EA

    2017-05-01

    Full Text Available Elizabeth A Duffy, Kathryn N Nelson Department of Health Behavior and Biological Sciences, The University of Michigan School of Nursing, Ann Arbor, MI, USA Abstract: A central venous catheter (CVC is an indwelling catheter that provides permanent or temporary stable venous access for both acute and chronically ill pediatric patients. These catheters provide stable venous access that can be used for a variety of medical purposes including drawing blood, hemodynamic monitoring, infusion of intravenous medications, infusion of intravenous fluids, chemotherapy, blood products, and parenteral nutrition. Each day, nurses access and care for CVCs in infants, children, and adolescents; the precision of this care can prevent life-threatening complications. The purpose of this review and the case study is to highlight the importance and components of evidence-based nursing practice in pediatric CVC care. A historical perspective of CVC care is provided in conjunction with current national initiatives to improve patient outcomes for children with CVCs. Infection prevention, clinical practice guidelines, quality improvement, and evidence-based care bundles are discussed. Keywords: pediatric nursing, central venous catheters, central line-associated bloodstream infection, care bundles, pediatric case study 

  7. Venous infraction of developmental venous anomaly: A case report with perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Youn; Kim, Hye Jeong; Hyun, Su Jeong; Kim, Hee Yeong; Kim, Han Myun; Hwang, Ji Young; Hong, Hye Suk; Woo, Ji Young; Yang, Ik [Dept. of Radiology, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul (Korea, Republic of); Kim, Eun Soo [Dept. of Radiology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang (Korea, Republic of)

    2017-06-15

    Developmental venous anomaly (DVA) is a common congenital venous malformation characterized by dilated medullary veins in caput medusa configuration and a draining vein. Despite the high incidence of DVAs, they are benign anatomic variations and rarely cause symptoms. Here, we report computed tomography and magnetic resonance imaging findings with perfusion images of acute infarction from underlying DVA in a 63-year-old female patient who presented with acute onset of neurologic symptoms and recovered without any neurologic deficit.

  8. The atherosclerosis of the sinus node artery is associated with an increased history of supra-ventricular arrhythmias: a retrospective study on 541 standard coronary angiograms

    Directory of Open Access Journals (Sweden)

    Michele M. Ciulla

    2015-08-01

    Full Text Available Background. The ischemic damage of the sinus node (SN is a well known cause of cardiac arrhythmias and can be a consequence of any flow abnormality in the sinus node artery (SNA. Accordingly we aimed this retrospective study to: (1 evaluate the suitability of the standard coronary angiography to study the SNA and (2 determine if the percentage of subjects with a positive retrospective history of supra-ventricular arrhythmias (SVA differs in patients with normal and diseased SNA ascertained at the time of coronary angiography.Methods and Results. Out of the 541 coronary angiograms reviewed the SNA was visible for its entire course in 486 cases (89.8%. It was found to arise from the right side of the coronary circulation in 266 cases (54.7% slightly more often than from the left, 219 cases (45.1%. One patient had 2 distinct SNA arising from either side of the coronary circulation. For the second objective, we studied the 333 patients with: (a coronary artery disease (CAD, (b properly evaluable SNA and (c complete clinical history available. In 51 (15.3% a SNA disease was found, 41.2% of them had a positive SVA history, mainly atrial fibrillation (AF, whereas only 7.4% of patients with a positive history of SVA could be found in the non-SNA diseased. This difference was statistically significant (P < 0.001.Conclusions. (1 The evaluation of the SNA is feasible in clinical practice during a standard coronary angiography; (2 this may be relevant since angiographically detectable SNA disease was significantly associated with a positive history of SVA.

  9. Pycnogenol® in chronic venous insufficiency and related venous disorders.

    Science.gov (United States)

    Gulati, Om P

    2014-03-01

    The present review provides an update of the biological profile of Pycnogenol in the light of its use in the treatment of chronic venous insufficiency (CVI) and related venous disorders such as deep vein thrombosis (DVT), post-thrombotic syndrome, long haul air-travel-related leg oedema, venous ulcers and acute haemorrhoids. Pycnogenol is a French maritime pine bark extract produced from the outer bark of Pinus pinaster Ait. subsp. atlantica. Its strong antioxidant, anti-inflammatory and vasodilator activities, antithrombotic effects and collagen stabilizing properties make it uniquely able to target the multi facet pathophysiology of CVI and related venous disorders. Clinical studies have shown that it can reduce oedema of the legs in CVI, reduce the incidence of deep venous thrombosis during long haul flights and enhance the healing of venous ulcers and haemorrhoidal episodes by topical application and/or oral administration. This review highlights clinical research findings on the safety, compliance and efficacy of Pycnogenol, including its use in combination products. Copyright © 2013 John Wiley & Sons, Ltd.

  10. [Thrombophlebitis of venous sinuses in otitis media].

    Science.gov (United States)

    Kuczkowski, Jerzy

    2007-01-01

    Thrombophlebitis of dura venous sinuses is a rare intracranial complication of otitis media, which may be sometimes accompanied by symptoms or sepsis. Anatomical conditions and early diagnosis of this vascular complication determine the treatment modality. Aim of this study was the assessment of diagnostics and treatment of venous sinuses thrombophlebitis in acute and chronic otitis media considering anatomy and the venous sinuses and status of coagulation system. Otogenic thrombophlebitis may occur in lateral, transverse, upper and lower petrosal sinuses, and rarely in cavernous. In some cases thrombophlebitis proces may expand into brain or emissary mastoid veins. Lateral sinus thrombophlebitis in chronic otitis media usually appears clinically as septic fever, earache, and increasing neurologic signs. In acute otitis media when thrombophlebitis develops the patient complains about headache, high fever and visual acquity. Diagnosis of venous sinus thrombophlebitis is based on clinical signs, radiological imaging (CT scan, MRI), bacteriological examinations and laboratory biochemical tests. Contrast enhanced CT scan shows "delta sign". Septic thrombophlebitis sinus sigmoidei is caused by mixed bacterial flora. Surgical treatment in cases with septic thrombus consists of radical modiffied ear operation and lateral sinus exposure. Thrombectomy and jugular vein ligation is performed when sepsis or thrombus is present. Mastoidectomy and tympanic cavity drainage is performed in cases with lateral sinus thrombosis in acute mastoiditis. Intravenous antibiotics therapy should be continued for 2 weeks. Anticoagulants should be given taking into consideration parameters of coagulation system and the type of thrombus. Treatment results of venous sinuses thrombophlebitis are good if they are not accompanied by other intracranial complications.

  11. Achieving Hard X-ray Nanofocusing Using a Wedged Multilayer Laue Lens

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaojing [Brookhaven National Lab. (BNL), Upton, NY (United States); Conley, Raymond [Brookhaven National Lab. (BNL), Upton, NY (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Bouet, Nathalie [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhou, Juan [Brookhaven National Lab. (BNL), Upton, NY (United States); Macrander, Albert [Argonne National Lab. (ANL), Argonne, IL (United States); Maser, Jorg [Argonne National Lab. (ANL), Argonne, IL (United States); Yan, Hanfei [Brookhaven National Lab. (BNL), Upton, NY (United States); Nazaretski, Evgeny [Brookhaven National Lab. (BNL), Upton, NY (United States); Lauer, Kenneth [Brookhaven National Lab. (BNL), Upton, NY (United States); Harder, Ross [Argonne National Lab. (ANL), Argonne, IL (United States); Robinson, Ian K. [Univ. College London, Bloomsbury (United Kingdom); Research Complex at Harwell, Oxfordshire (United Kingdom); Kalbfleisch, Sebastian [Brookhaven National Lab. (BNL), Upton, NY (United States); Chu, Yong S. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-05-04

    Here, we report on the fabrication and the characterization of a wedged multilayer Laue lens for x-ray nanofocusing. The lens was fabricated using a sputtering deposition technique, in which a specially designed mask was employed to introduce a thickness gradient in the lateral direction of the multilayer. X-ray characterization shows an efficiency of 27% and a focus size of 26 nm at 14.6 keV, in a good agreement with theoretical calculations. Our results indicate that the desired wedging is achieved in the fabricated structure. Furthermore, we anticipate that continuous development on wedged MLLs will advance x-ray nanofocusing optics to new frontiers and enrich capabilities and opportunities for hard X-ray microscopy.

  12. Effectiveness of a Wedge Probe to Measure Sonic Boom Signatures in a Supersonic Wind Tunnel

    Science.gov (United States)

    Wilcox, Floyd J., Jr.; Elmiligui, Alaa A.

    2013-01-01

    A wind tunnel investigation was conducted in the Langley Unitary Plan Wind Tunnel (UPWT) to determine the effectiveness of a wedge probe to measure sonic boom pressure signatures compared to a slender conical probe. A generic business jet model at a constant angle of attack and at a single model to probe separation distance was used to generate a sonic boom signature. Pressure signature data were acquired with both the wedge probe and a slender conical probe for comparison. The test was conducted at a Mach number of 2.0 and a free-stream unit Reynolds number of 2 million per foot. The results showed that the wedge probe was not effective in measuring the sonic boom pressure signature of the aircraft model in the supersonic wind tunnel. Data plots and a discussion of the results are presented. No tabulated data or flow visualization photographs are included.

  13. Wedge Shock and Nozzle Exhaust Plume Interaction in a Supersonic Jet Flow

    Science.gov (United States)

    Castner, Raymond; Zaman, Khairul; Fagan, Amy; Heath, Christopher

    2014-01-01

    Fundamental research for sonic boom reduction is needed to quantify the interaction of shock waves generated from the aircraft wing or tail surfaces with the nozzle exhaust plume. Aft body shock waves that interact with the exhaust plume contribute to the near-field pressure signature of a vehicle. The plume and shock interaction was studied using computational fluid dynamics and compared with experimental data from a coaxial convergent-divergent nozzle flow in an open jet facility. A simple diamond-shaped wedge was used to generate the shock in the outer flow to study its impact on the inner jet flow. Results show that the compression from the wedge deflects the nozzle plume and shocks form on the opposite plume boundary. The sonic boom pressure signature of the nozzle exhaust plume was modified by the presence of the wedge. Both the experimental results and computational predictions show changes in plume deflection.

  14. Angular tolerances and trapped internal reflections in wedged high refractive index Brewster's angle plates

    Science.gov (United States)

    Rutt, H. N.

    1997-02-01

    It is well known that the angular alignment tolerance for Brewster's angle plates is not generally strict. It is often not appreciated that for high index plates however wedge tolerances are small. It is shown that in Brewster angle plates of high refractive index materials, small wedge angles in the fabricated plate can cause internal s-plane reflections to become 'trapped' by total internal reflection. A wedge angle acceptable in terms of its p-plane loss can cause such trapped reflections. In laser systems the resulting multiply reflected beams can move sideways in the plate and eventually hit o-ring seals or other mounting arrangements, causing component damage and leaks in unexpected locations. Stray light problems of an unexpected nature can occur from this effect in both laser based and conventional optical devices.

  15. A quantum hybrid with a thin antenna at the vertex of a wedge

    Energy Technology Data Exchange (ETDEWEB)

    Carlone, Raffaele, E-mail: raffaele.carlone@unina.it [Università “Federico II” di Napoli, Dipartimento di Matematica e Applicazioni “R. Caccioppoli”, MSA, via Cinthia, I-80126, Napoli (Italy); Posilicano, Andrea, E-mail: andrea.posilicano@uninsubria.it [DiSAT, Università dell' Insubria, via Valleggio 11, I-22100, Como (Italy)

    2017-03-26

    We study the spectrum, resonances and scattering matrix of a quantum Hamiltonian on a “hybrid surface” consisting of a half-line attached by its endpoint to the vertex of a concave planar wedge. At the boundary of the wedge, outside the vertex, homogeneous Dirichlet conditions are imposed. The system is tunable by varying the measure of the angle at the vertex. - Highlights: • Spectral characterization of a quantum Hamiltonian on “hybrid surface” consisting of a halfline attached to the vertex of a concave planar wedge. • The system is tunable by varying the measure of the angle at the vertex. • Relation between the conduction properties inside the hybrid and formation of resonances. • Easy generalization of the results to more complicated structures.

  16. The synthesis and adsorption properties of some carbohydrate-terminated dendrimer wedges

    CERN Document Server

    Ainsworth, R L

    1997-01-01

    A range of dendritic molecules that are designed to bind to a cotton surface has been synthesised. The architecture of the molecules allows the location of various functional, property modifying units at the focus and the attachment of recognition groups at the periphery of a dendritic molecule with wedge topology. The synthesis and characterisation of dendrimer wedges up to the second generation using a divergent approach has been performed. These wedges are readily built up using a simple and efficient stepwise pathway from the central core, and surface recognising species are subsequently attached to the molecule utilising procedures developed in conjunction with Unilever Research Laboratories. Work has been carried out to assess their adsorption onto a cotton surface and the postulated adsorption mechanism is discussed.

  17. [Teeth wedge-shaped defects in adults of different age groups: remark to prevention and treatment].

    Science.gov (United States)

    Iordanishvili, A K; Pikhur, O L; Cherni, D A

    The aim of the study was to assess the treatment of teeth wedge defects in different age groups. Records of 383 patients (125 males and 258 females aged 22-85 years) treated in outpatient dental facilities with different ownership forms. It is shown that the medical care of patients with wedge-shaped teeth defects routinely consists of remineralization therapy and restoration of anatomical teeth shape regardless of the form of ownership. The extensiveness of dental rehabilitation as well as the use of more modern technologies are typical for private clinics and 96-100% of patients finished their treatment there. In the state and departmental institutions complete rehabilitation of wedge-shaped defects was provided in 45.5-58.0% and 54.3-83.9, respectively. The paper also highlights the drawbacks of primary medical documentation identified in medical institutions of all forms of ownership.

  18. Advances in diagnosis and treatment of cerebral venous system diseases

    Directory of Open Access Journals (Sweden)

    Xiao-yun LIU

    2016-11-01

    Full Text Available Cerebral venous system diseases include cerebral venous thrombosis (CVT, venous sinus stenosis, carotid cavernous fistula (CCF, intracranial arteriovenous malformation (AVM and so on. In recent years, due to the rapid development of neuroimaging and interventional technology, more and more cerebral venous system diseases have been timely diagnosed and treated, such as magnetic resonance black-blood thrombus imaging (MRBTI in the diagnosis of CVT, stenting in the treatment of venous sinus stenosis, micro coil plus Onyx glue or covered stents in the treatment of CCF, which allow us to make a deeper recognition of cerebral venous system diseases. Therefore, this paper will introduce the latest diagnosis and treatment of cerebral venous system diseases. DOI: 10.3969/j.issn.1672-6731.2016.11.006

  19. Is kyphoplasty better than vertebroplasty at restoring form and function after severe vertebral wedge fractures?

    Science.gov (United States)

    Landham, Priyan R; Baker-Rand, Holly L A; Gilbert, Samuel J; Pollintine, Phillip; Annesley-Williams, Deborah J; Adams, Michael A; Dolan, Patricia

    2015-04-01

    The vertebral augmentation procedures, vertebroplasty and kyphoplasty, can relieve pain and facilitate mobilization of patients with osteoporotic vertebral fractures. Kyphoplasty also aims to restore vertebral body height before cement injection and so may be advantageous for more severe fractures. The purpose of this study was to compare the ability of vertebroplasty and kyphoplasty to restore vertebral height, shape, and mechanical function after severe vertebral wedge fractures. This is a biomechanical and radiographic study using human cadaveric spines. Seventeen pairs of thoracolumbar "motion segments" from cadavers aged 70-98 years were injured, in a two-stage process involving flexion and compression, to create severe anterior wedge fractures. One of each pair underwent vertebroplasty and the other kyphoplasty. Specimens were then compressed at 1 kN for 1 hour to allow consolidation. Radiographs were taken before and after injury, after treatment, and after consolidation. At these same time points, motion segment compressive stiffness was assessed, and intervertebral disc "stress profiles" were obtained to characterize the distribution of compressive stress on the vertebral body and neural arch. On average, injury reduced anterior vertebral body height by 34%, increased its anterior wedge angle from 5.0° to 11.4°, reduced intradiscal (nucleus) pressure and motion segment stiffness by 96% and 44%, respectively, and increased neural arch load bearing by 57%. Kyphoplasty caused 97% of the anterior height loss to be regained immediately, although this reduced to 79% after consolidation. Equivalent gains after vertebroplasty were significantly lower: 59% and 47%, respectively (pKyphoplasty reduced vertebral wedging more than vertebroplasty (pkyphoplasty and vertebroplasty. After severe vertebral wedge fractures, vertebroplasty and kyphoplasty were equally effective in restoring mechanical function. However, kyphoplasty was better able to restore vertebral

  20. Combining valgus knee brace and lateral foot wedges reduces external forces and moments in osteoarthritis patients.

    Science.gov (United States)

    Jafarnezhadgero, Amir Ali; Oliveira, Anderson S; Mousavi, Seyed Hamed; Madadi-Shad, Morteza

    2018-01-01

    Osteoarthritis progression can be related to the external knee adduction and flexion moments during walking. Lateral foot wedges and knee braces have been used as treatment for osteoarthritis, but little is known about their influence on knee joint moments generated in the sagittal and frontal planes. Therefore, the aim of the present study was determine the effects of the isolated and combined use of valgus knee brace and lateral wedge foot orthotic on peak forces and moments during gait in knee osteoarthritis patients. Twenty four males (age: 62.1±2.0years) with varus alignment, symptomatic medial compartment knee osteoarthritis participated in this study. Subjects walked over ground at preferred speed in four conditions: (1) no assistive device (control); (2) using lateral wedges, (3) using knee braces, and (4) using both lateral wedges and knee braces. Ground reaction forces (GRF) and moments, as well as lower limb kinematics were recorded. Peak GRF, vertical loading rate, free moment, external knee adduction and flexion moments were compared across conditions. The concurrent use of lateral wedge and knee brace reduced the first peak GRF in the vertical (6%, p=0.002), anterior-posterior (30%, p=0.028) and medial-lateral directions (44%, p=0.029). Moreover, the use of these devices reduced the peak external knee adduction moment (25%, p=0.019), but not the external flexion moment and free moment (p>0.05). The combined use of lateral wedges and knee braces can reduce medial-lateral knee joint loading, but despite reduced peak forces in the sagittal plane, these device do not reduce joint moments. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. The importance of mantle wedge heterogeneity to subduction zone magmatism and the origin of EM1

    Science.gov (United States)

    Turner, Stephen J.; Langmuir, Charles H.; Dungan, Michael A.; Escrig, Stephane

    2017-08-01

    The composition of the convecting asthenospheric mantle that feeds the mantle wedge can be investigated via rear-arc lavas that have minimal slab influence. This "ambient mantle wedge" composition (the composition of the wedge prior to the addition of a slab component) varies substantially both worldwide and within individual arcs. 143Nd/144Nd measurements of rear-arc samples that have minimal slab influence are similar to 143Nd/144Nd in the stratovolcanoes of the adjacent volcanic fronts, suggesting that 143Nd/144Nd of arc-front volcanics are largely inherited from the ambient mantle composition. 143Nd/144Nd correlates with ratios such as Th/U, Zr/Nb, and La/Sm, indicating that these ratios also are strongly influenced by ambient wedge heterogeneity. The same phenomenon is observed among individual volcanoes from the Chilean Southern Volcanic Zone (SVZ), where along-strike variability of the volcanic front tracks that of rear-arc monogenetic volcanics. Depleted mantle wedges are more strongly influenced by slab-derived components than are enriched wedges. This leads to surprising trace element correlations in the global dataset, such as between Pb/Nb and Zr/Nb, which are not explicable by variable compositions or fluxes of slab components. Depleted ambient mantle is present beneath arcs with back-arc spreading; relatively enriched mantle is present adjacent to continents. Ambient mantle wedge heterogeneity both globally and regionally forms isotope mixing trajectories for Sr, Nd and Hf between depleted mantle and EM1-type enriched compositions as represented by Gough Island basalts. Making use of this relationship permits a quantitative match with the SVZ data. It has been suggested that EM1-type mantle reservoirs are the result of recycled lower continental crust, though such models do not account for certain trace element ratios such as Ce/Pb and Nb/U or the surprisingly homogeneous trace element compositions of EM1 volcanics. A model in which the EM1 end

  2. Developing a numerical model of ice wedge degradation and trough formation

    Science.gov (United States)

    Garayshin, V.; Nicolsky, D.; Romanovsky, V. E.

    2014-12-01

    The research was initiated as a part of the Next-Generation Ecosystem Experiments (NGEE) in the Arctic and also as a part of the Integrated Ecosystem Model for Alaska. The presented project explores influence of climate (mean annual and summer temperatures, and snow cover depth and density) and physical properties, soil textures and moisture content on thawing and destabilization of ice wedges on the North Slope of Alaska. Recall that ice wedges formed many years ago, when ground cracked and the cracks were filled by water. The infiltrated water then became frozen and turned into ice. When the annual and summer air temperatures become higher, the depth of the active layer increases. Deeper seasonal thawing may cause melting of the ice wedges from their tops. Consequently, the ground starts to settle and a trough form above the ice wedge. Once the trough is formed, the winter snow cover becomes deeper above it and provides a potential feedback mechanism to the further degradation of permafrost. The work deals with analysis of temperature regimes and moisture distribution and dynamics during seasonal cycles of freezing and thawing. The research focuses on the development of a computational approach to the study of seasonal temperature dynamics of the active layer, ice wedge and surrounding it permafrost. A thermo-mechanical model of the ice wedge based on principles of macroscopic thermodynamics and continuum mechanics is presented. The model includes the energy and mass conservation equations, a visco-poroelastic rheology for ground deformation, and an empirical formula which relates unfrozen water content to temperature. The complete system is reduced to a computationally convenient set of coupled equations for the temperature, pore water pressure, ground velocities and porosity in a two-dimensional domain. A finite element method and an implicit scheme in time were utilized to construct a non-linear system of equations, which was solved iteratively. The model

  3. Three-dimensional vertebral wedging and pelvic asymmetries in the early stages of adolescent idiopathic scoliosis.

    Science.gov (United States)

    Begon, Mickaël; Scherrer, Sophie-Anne; Coillard, Christine; Rivard, Charles-Hilaire; Allard, Paul

    2015-03-01

    Scoliosis is a three-dimensional (3D) deformation of the spine and the pelvis. Although the relation between the pelvic asymmetries and scoliosis progression was proposed by several authors, it has not been documented over time in adolescent idiopathic scoliosis (AIS). The objective was to determine whether vertebral wedging and pelvic asymmetries progress in the early stages of AIS before any orthopedic treatment. The study design included an observational cohort study. Nineteen AIS girls participated in this study. The outcome measures were pelvic and spine geometries from simultaneous biplanar radiographs. At the diagnosis, the girls (12.6±1.3 years) had a Cobb angle of 13.9°±6.0°. At the end of their observation period (11 months on average), the scoliosis progressed to 20.5°±5.5°. Bone 3D geometry was reconstructed from biplanar radiographs. Sagittal and frontal wedgings were calculated for five vertebral levels, namely, at the apex and at the two vertebral bodies above and below it. The pelvic geometry was described using five 3D homologous right-left lengths to estimate pelvic asymmetries. Paired t tests were performed on vertebral wedging and pelvic asymmetries to assess their progression between the two evaluations. Principal component (PC) analyses were applied to determine whether vertebral wedging or pelvic asymmetries were predominant at each evaluation. Vertebral wedging was present at the diagnosis (1.76°-5.92°) and generally did not progress until brace prescription. The mean difference between the right and left pelvic normalized lengths was 1.4% and 2.4% for the initial and final evaluations, respectively. Results revealed the width of the right pelvis to be superior by 3%, and this asymmetry progressed to 4.0%. Principal component analysis revealed that initial vertebral wedging was present in seven out of eight parameters of the first three PCs, whereas at the final examination, vertebral wedging and pelvic asymmetries were evenly

  4. Comparison of infinite and wedge fringe settings in Mach Zehnder interferometer for temperature field measurement

    Energy Technology Data Exchange (ETDEWEB)

    Haridas, Divya [Department of Physics, National Institute of Technology Calicut, Kerala, 673601 (India); P, Vibin Antony; Sajith, V.; Sobhan, C. B. [School of Nano Science and Technology, National Institute of Technology Calicut, Kerala, 673601 (India)

    2014-10-15

    Interferometric method, which utilizes the interference of coherent light beams, is used to determine the temperature distribution in the vicinity of a vertical heater plate. The optical components are arranged so as to obtain wedge fringe and infinite fringe patterns and isotherms obtained in each case were compared. In wedge fringe setting, image processing techniques has been used for obtaining isotherms by digital subtraction of initial parallel fringe pattern from deformed fringe pattern. The experimental results obtained are compared with theoretical correlations. The merits and demerits of the fringe analysis techniques are discussed on the basis of the experimental results.

  5. Developing a numerical model of ice wedge degradation and trough formation

    Science.gov (United States)

    Garayshin, V.; Nicolsky, D.; Romanovsky, V. E.

    2016-12-01

    The research was initiated as a part of the Next-Generation Ecosystem Experiments (NGEE) in the Arctic and also as a part of the Integrated Ecosystem Model for Alaska. The presented project explores influence of climate (mean annual and summer temperatures, snow cover depth and physical properties), and soil textures and moisture content on thawing and destabilization of ice wedges on the North Slope of Alaska using numerical modeling. The ice wedges on the North Slope of Alaska have being forming for many millennia, when ground cracked and the cracks were filled with snowmelt water. The infiltrated water then became frozen and turned into ice. When the annual and summer air temperatures become higher, the depth of the active layer increases. Deeper seasonal thawing may cause melting of the ice wedges from their tops. Consequently, the ground starts to settle and a trough form above the ice wedge. Once the trough is formed, the winter snow cover becomes deeper above it and provides a potential positive feedback mechanism to the further degradation of permafrost. The presented work deals with analysis of temperature regimes and dynamics during seasonal cycles of freezing and thawing. The research focuses on the development of a computational approach to the study of seasonal temperature dynamics of the active layer, ice wedge and surrounding it permafrost. A thermo-mechanical model of the ice wedge based on principles of macroscopic thermodynamics and continuum mechanics was developed and will be presented. The model includes the energy and mass conservation equations, a visco-elastic rheology for ground deformation, and an empirical formula which relates unfrozen water content to temperature. The complete system is reduced to a computationally convenient set of coupled equations for the temperature, ground displacements and porosity in a two-dimensional domain. A finite element method and an implicit scheme in time were utilized to construct a non-linear system of

  6. Predictors and Outcomes of Recurrent Venous Thromboembolism in Elderly Patients.

    Science.gov (United States)

    Lauber, Sandro; Limacher, Andreas; Tritschler, Tobias; Stalder, Odile; Méan, Marie; Righini, Marc; Aschwanden, Markus; Beer, Jürg Hans; Frauchiger, Beat; Osterwalder, Josef; Kucher, Nils; Lämmle, Bernhard; Cornuz, Jacques; Angelillo-Scherrer, Anne; Matter, Christian M; Husmann, Marc; Banyai, Martin; Staub, Daniel; Mazzolai, Lucia; Hugli, Olivier; Rodondi, Nicolas; Aujesky, Drahomir

    2018-01-04

    Little is known about predictors and outcomes of recurrent venous thromboembolism in elderly patients. We prospectively followed up 991 patients aged ≥65 years with acute venous thromboembolism in a multicenter Swiss cohort study. The primary outcome was symptomatic recurrent venous thromboembolism. We explored the association between baseline characteristics and treatments and recurrent venous thromboembolism using competing risk regression, adjusting for periods of anticoagulation as a time-varying co-variate. We also assessed the clinical consequences (case-fatality, localization) of recurrent venous thromboembolism. During a median follow-up period of 30 months, 122 patients developed recurrent venous thromboembolism, corresponding to a 3-year cumulative incidence of 14.8%. The case-fatality of recurrence was high (20.5%), particularly in patients with unprovoked (23%) and cancer-related venous thromboembolism (29%). After adjustment, only unprovoked venous thromboembolism (sub-hazard ratio [SHR] 1.67 compared to provoked venous thromboembolism; 95% confidence interval [CI] 1.00-2.77) and proximal deep vein thrombosis (SHR 2.41 compared to isolated distal deep vein thrombosis; 95% CI 1.07-5.38) were significantly associated with recurrence. Patients with initial pulmonary embolism were more likely to have another pulmonary embolism as a recurrent event than patients with deep vein thrombosis. Elderly patients with acute venous thromboembolism have a substantial long-term risk of recurrent venous thromboembolism and recurrence carries a high case-fatality rate. Only two factors, unprovoked venous thromboembolism and proximal deep vein thrombosis, were independently associated with recurrent venous thromboembolism, indicating that traditional risk factors for venous thromboembolism recurrence (e.g., cancer) may be less relevant in the elderly. Copyright © 2018. Published by Elsevier Inc.

  7. Determination of refractive index of a simple negative, positive, or zero power lens using wedged plated interferometer

    Science.gov (United States)

    Shukla, R. P.; Perera, G. M.; George, M. C.; Venkateswarlu, P.

    1990-01-01

    A nondestructive technique for measuring the refractive index of a negative lens using a wedged plate interferometer is described. The method can be also used for measuring the refractive index of convex or zero power lenses. Schematic diagrams are presented for the use of a wedged plate interferometer for measuring the refractive index of a concave lens and of a convex lens.

  8. Evaluation of off-axis wedge correction factor using diode dosimeters for estimation of delivered dose in external radiotherapy

    Directory of Open Access Journals (Sweden)

    Mahmoud Allahverdi

    2012-01-01

    Full Text Available An in vivo dosimetry system, using p-type diode dosimeters, was characterized for clinical applications of treatment machines ranging in megavoltage energies. This paper investigates two different models of diodes for externally wedged beams and explains a new algorithm for the calculation of the target dose at various tissue depths in external radiotherapy. The values of off-axis wedge correction factors were determined at two different positions in the wedged (toward the thick and thin edges and in the non-wedged directions on entrance and exit surfaces of a polystyrene phantom in 60 Co and 6 MV photon beams. Depth transmission was defined on the entrance and exit surfaces to obtain the off-axis wedge correction factor at any depth. As the sensitivity of the diodes depends on physical characteristics [field size, source-skin distance (SSD, thickness, backscatter], correction factors were applied to the diode reading when measuring conditions different from calibration situations . The results indicate that needful correction factors for 60 Co wedged photons are usually larger than those for 6 MV wedged photon beams. In vivo dosimetry performed with the proposed algorithms at externally wedged beams has negligible probable errors (less than 0.5% and is a reliable method for patient dose control.

  9. Commissioning Siemens Virtual Wedges in the Oncentra MasterPlan treatment planning system using Gafchromic EBT film.

    Science.gov (United States)

    Ferretti, A; Simonato, F; Zandonà, R; Reccanello, S; Fabbris, R

    2010-12-01

    Virtual Wedges were introduced in Siemens LINACs to improve the treatment workflow. The aim of the present work is the validation of dose calculation by MasterPlan-Oncentra treatment planning system for virtual wedged beams. The Oncor Siemens accelerator installed in the authors' department produces 6 and 15 MV photon beams. At first, the consistency of VW LINAC production was tested and the EBT film measuring method was verified. This method is based on the scanner uniformity correction and absolute dose calibration as reported in literature. Then, the measured and calculated wedge factors and beam profiles are compared. For 15 degrees, 30 degrees, 45 degrees, and 60 degrees wedge angles, the wedge factors for different field sizes were measured by an ionization chamber and the dose profiles were acquired by Gafchromic EBT film. Both types of measurements were collected in isocentric condition. The comparison between measured and calculated VW factors shows discrepancies that increase with field size and angle. The OTP Enhanced algorithm produces better agreement with measurements than the Classic one, with improvement overall visible for large angles. The agreement between measured and planned beam profiles is within limits reported by the ESTRO Booklet No. 7 in terms of confidence limits. The MasterPlan-Oncentra treatment planning system determines wedge factors and VW profiles within the requested accuracy in the majority of treatment conditions. For big field dimensions and wedge angle, wedge factor accordance was worse, but it may be increased with an improvement of the LINAC dosimetric board calibration.

  10. Cerebral Venous Thrombosis Presenting with Subracnoid Hemorrhage

    Directory of Open Access Journals (Sweden)

    Esra Eruyar

    2015-08-01

    Full Text Available Subarachnoid hemorrhage (SAH associated with cerebral venous thrombosis (CVT is rarely reported. In our case, the initial CT shows with suspected lesions that SAH. After the initial diagnosis of SVT with history and neurological examination findings MRV taken and consistend with thrombus signal change. Dural sinus thrombosis with secondary venous hypertension may lead to SAH into the subarachnoid space due to the rupture of fragile, thin-walled cortical veins. Patients with non-traumatic, non-aneurysmal and non-perimesencephalic subaracnoid hemorrhage tend to have clots circumscribed along the cortical convexity, a condition referred as acute cortical SAH. CVT is a potential cause of cortical SAH. This case; SAH may be the first sign of SVT and especially SVT must do in etiologic research without the involvement of the basal sisterna in cases of SAH.

  11. Intracranial venous thrombosis complicating oral contraception

    Science.gov (United States)

    Dindar, F.; Platts, M. E.

    1974-01-01

    Four days after the onset of a severe headache a 22-year-old woman who had been taking oral contraceptives for less than three weeks had a convulsion, followed by right hemiparesis. Other focal neurologic signs and evidence of raised intracranial pressure appeared, and she became comatose on the seventh day. A left craniotomy revealed extensive cerebral venous thrombosis. She died the next day. On postmortem examination extensive thrombosis of the superior sagittal sinus and draining cerebral veins, and multiple areas of cerebral hemorrhage and hemorrhagic infarction were seen. Some of the superficial cerebral veins showed focal necrosis of their walls, and the lateral lacunae of the superior sagittal sinus contained proliferating endothelial cells. The adrenal veins were also thrombosed. The significance of these findings is discussed. The literature on cerebrovascular complications of oral contraception, particularly cerebral venous thrombosis, is reviewed. ImagesFIG. 1FIG. 2FIG. 3FIG. 4FIG. 5FIG. 6 PMID:4413961

  12. Navigating venous access: a guide for hospitalists.

    Science.gov (United States)

    Simonov, Michael; Pittiruti, Mauro; Rickard, Claire M; Chopra, Vineet

    2015-07-01

    Venous access is the foundation for safe and effective hospital-based care. Inpatient providers must have a deep knowledge of the different types of venous access devices (VADs), their relative indications, contraindications, and appropriateness. However, such knowledge is difficult to come by and usually only gleaned through years of clinical experience. To bridge this gap, we provide an in-depth summary of the relevant anatomical considerations, physical characteristics, advantages, and disadvantages of VADs commonly used in the hospital setting. In doing so, we seek to improve the safety and share the science of vascular access with frontline clinicians. To aid decision-making, we conclude by operationalizing the available data through algorithms that outline appropriate vascular access for the hospitalized patient. © 2015 Society of Hospital Medicine.

  13. Portal Venous Interventions: State of the Art.

    Science.gov (United States)

    Madoff, David C; Gaba, Ron C; Weber, Charles N; Clark, Timothy W I; Saad, Wael E

    2016-02-01

    In recent decades, there have been numerous advances in the management of liver cancer, cirrhosis, and diabetes mellitus. Although these diseases are wide ranging in their clinical manifestations, each can potentially be treated by exploiting the blood flow dynamics within the portal venous system, and in some cases, adding cellular therapies. To aid in the management of these disease states, minimally invasive transcatheter portal venous interventions have been developed to improve the safety of major hepatic resection, to reduce the untoward effects of sequelae from end-stage liver disease, and to minimize the requirement of exogenously administered insulin for patients with diabetes mellitus. This state of the art review therefore provides an overview of the most recent data and strategies for utilization of preoperative portal vein embolization, transjugular intrahepatic portosystemic shunt placement, balloon retrograde transvenous obliteration, and islet cell transplantation. © RSNA, 2016.

  14. Central venous obstruction in the thorax.

    Science.gov (United States)

    Collin, G; Jones, R G; Willis, A P

    2015-06-01

    Central venous stenosis and occlusion can occur secondary to a spectrum of conditions ranging from aggressive malignancy to benign extrinsic anatomical compression in otherwise healthy individuals. Irrespective of aetiology, significant morbidity in the acute setting and long term can occur unless prompt accurate diagnosis and appropriate management is initiated, the radiologist being central to both. The present review will provide radiologists with a thorough illustration and explanation of the range of central venous conditions in the thorax (including deep vein thrombosis, thoracic outlet syndrome, haemodialysis, and malignancy related causes), the salient imaging findings and interventional management using case examples from the authors' practice. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  15. Ultrasound-guided peripheral venous access for therapeutic apheresis procedures reduces need for central venous catheters.

    Science.gov (United States)

    Salazar, Eric; Garcia, Salvador; Miguel, Robin; Segura, Francisco J; Ipe, Tina S; Leveque, Christopher

    2017-08-01

    Therapeutic and donor apheresis requires adequate vascular access to achieve inlet flow rates of ∼50-100 mL/min. While central dialysis-type venous catheters can usually provide such access, their use includes several associated risks. Some of these risks can be avoided or diminished if adequate peripheral venous access can be established. Some patients have adequate peripheral veins for apheresis that cannot be readily identified visually or by palpation. We hypothesized that ultrasound-guided peripheral venous access would benefit such patients and would lead to placement of fewer central venous catheters. The technique of ultrasound-guided peripheral access for apheresis has been in use at Houston Methodist Hospital since 2012. We performed a prospective review of patients undergoing inpatient and outpatient apheresis at Houston Methodist Hospital from July 1, 2015 to September 30, 2015, to assess its benefit. During this time, we performed 831 procedures on 186 patients, including 787 therapeutic plasma exchanges, three red blood cell exchanges, 41 peripheral stem cell collections. Ultrasound-guided vascular access was used for 68 procedures (8% of all procedures), including 62 therapeutic plasma exchanges, 4 peripheral stem cell collections, and 2 red blood cell changes. Use of ultrasound-guided peripheral access prevented the placement of central venous catheters in 37 (20%) patients, demonstrating its utility in a busy transfusion service. © 2016 Wiley Periodicals, Inc.

  16. Femoral venous oxygen saturation and central venous oxygen saturation in critically ill patients.

    Science.gov (United States)

    Zhang, Xiaohong; Wang, Jiandong; Dong, Yun; Chen, Youdai

    2015-08-01

    To investigate the relationship between central venous oxygen saturation (ScvO(2)) and femoral venous oxygen saturation (SfvO(2)) in a large group of critically ill patients. Observational study. A group of unselected critically ill patients with central line placed into superior vena cava were included. A 26-bed intensive care unit in a tertiary referral hospital. None. Venous blood samples of superior vena cava and femoral vein were collected within an interval of 5 to 15 minutes and analyzed with blood gas/electrolyte analyzer immediately. Although SfvO(2) was significantly correlated with ScvO(2) (r = 0.493, P 731 pairs of blood samples collected from 357 patients. The fit line of scatter diagram ScvO(2) vs SfvO(2) had a large intercept (48.68%) and a low slope (0.2978); ScvO(2) was still around 50% while SfvO(2) was nearing 0%. The distribution of blood flow, measured with Doppler ultrasound, had a similar trend in 237 patients and 412 measurements. The ratio of femoral artery flow over common carotid artery flow varied widely (from 0 to 7.13). Blood flow was not distributed in a fixed ratio to the superior vena cava-drained organs and tissues. Central venous oxygen saturation was not representative of the whole systemic circulation in critically ill patients. Central venous oxygen saturation alone might be misleading in goal-directed therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Program requirements for fellowship education in venous and lymphatic medicine.

    Science.gov (United States)

    Comerota, Anthony J; Min, Robert J; Rathbun, Suman W; Khilnani, Neil; Rooke, Thom; Wakefield, Thomas W; Carman, Teresa L; Lurie, Fedor; Vedantham, Suresh; Zimmet, Steven E

    2017-08-01

    Background In every field of medicine, comprehensive education should be delivered at the graduate level. Currently, no single specialty routinely provides a standardized comprehensive curriculum in venous and lymphatic disease. Method The American Board of Venous & Lymphatic Medicine formed a task force, made up of experts from the specialties of dermatology, family practice, interventional radiology, interventional cardiology, phlebology, vascular medicine, and vascular surgery, to develop a consensus document describing the program requirements for fellowship medical education in venous and lymphatic medicine. Result The Program Requirements for Fellowship Education in Venous and Lymphatic Medicine identify the knowledge and skills that physicians must master through the course of fellowship training in venous and lymphatic medicine. They also specify the requirements for venous and lymphatic training programs. The document is based on the Core Content for Training in Venous and Lymphatic Medicine and follows the ACGME format that all subspecialties in the United States use to specify the requirements for training program accreditation. The American Board of Venous & Lymphatic Medicine Board of Directors approved this document in May 2016. Conclusion The pathway to a vein practice is diverse, and there is no standardized format available for physician education and training. The Program Requirements for Fellowship Education in Venous and Lymphatic Medicine establishes educational standards for teaching programs in venous and lymphatic medicine and will facilitate graduation of physicians who have had comprehensive training in the field.

  18. [Implantable venous access ports, nursing practices].

    Science.gov (United States)

    Ourliac, Maryse; Dijols-Lécuyer, Isabelle

    2016-05-01

    Following the publication of national recommendations regarding the handling of implantable venous access ports, an observation audit was carried out in a hospital in 2013. This enabled an assessment of the existing system to be performed, current practices to be compared with the hospital's protocol and adapted corrective measures to be put in place. A further audit carried out in 2015 was particularly encouraging. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  19. Parenchymal abnormalities associated with developmental venous anomalies

    Energy Technology Data Exchange (ETDEWEB)

    San Millan Ruiz, Diego; Gailloud, Philippe [Johns Hopkins Hospital, Division of Interventional Neuroradiology, Baltimore, MD (United States); Delavelle, Jacqueline [Geneva University Hospital, Neuroradiology Section, Department of Radiology and Medical Informatics, Geneva (Switzerland); Yilmaz, Hasan; Ruefenacht, Daniel A. [Geneva University Hospital, Section of Interventional Neuroradiology, Department of Clinical Neurosciences, Geneva (Switzerland); Piovan, Enrico; Bertramello, Alberto; Pizzini, Francesca [Verona City Hospital, Service of Neuroradiology, Verona (Italy)

    2007-12-15

    To report a retrospective series of 84 cerebral developmental venous anomalies (DVAs), focusing on associated parenchymal abnormalities within the drainage territory of the DVA. DVAs were identified during routine diagnostic radiological work-up based on magnetic resonance imaging (MRI) (60 cases), computed tomography (CT) (62 cases) or both (36 cases). Regional parenchymal modifications within the drainage territory of the DVA, such as cortical or subcortical atrophy, white matter density or signal alterations, dystrophic calcifications, presence of haemorrhage or a cavernous-like vascular malformation (CVM), were noted. A stenosis of the collecting vein of the DVA was also sought for. Brain abnormalities within the drainage territory of a DVA were encountered in 65.4% of the cases. Locoregional brain atrophy occurred in 29.7% of the cases, followed by white matter lesions in 28.3% of MRI investigations and 19.3% of CT investigations, CVMs in 13.3% of MRI investigations and dystrophic calcification in 9.6% of CT investigations. An intracranial haemorrhage possibly related to a DVA occurred in 2.4% cases, and a stenosis on the collecting vein was documented in 13.1% of cases. Parenchymal abnormalities were identified for all DVA sizes. Brain parenchymal abnormalities were associated with DVAs in close to two thirds of the cases evaluated. These abnormalities are thought to occur secondarily, likely during post-natal life, as a result of chronic venous hypertension. Outflow obstruction, progressive thickening of the walls of the DVA and their morphological organization into a venous convergence zone are thought to contribute to the development of venous hypertension in DVA. (orig.)

  20. The controversy on chronic cerebrospinal venous insufficiency

    Directory of Open Access Journals (Sweden)

    Paolo Zamboni

    2013-08-01

    Full Text Available The objective of this review is to analyze the actual scientific controversy on chronic cerebrospinal venous insufficiency (CCSVI and its association with both neurodegenerative disorders and multiple sclerosis (MS. We revised all published studies on prevalence of CCSVI in MS patients, including ultrasound and catheter venography series. Furthermore, we take into consideration other publications dealing with the pathophysiologic consequences of CCSVI in the brain, as well as ecent data characterizing the pathology of the venous wall in course of CCSVI. Finally, safety and pilot data on effectiveness of endovascular CCSVI treatment were further updated. Studies of prevalence show a big variability in prevalence of CCSVI in MS patients assessed by established ultrasonographic criteria. This could be related to high operator dependency of ultrasound. However, 12 studies, by the means of more objective catheter venography, show a prevalence >90% of CCSVI in MS. Global hypo-hypoperfusion of the brain, and reduced cerebral spinal fluid dynamics in MS was shown to be related to CCSVI. Postmortem studies and histology corroborate the 2009 International Union of Phlebology (UIP Consensus decision to insert CCSVI among venous malformations. Finally, safety of balloon angioplasty of the extracranial veins was certainly demonstrated, while prospective data on the potential effectiveness of endovascular treatment of CCSVI support to increase the level of evidence by proceeding with a randomized control trial (RCT. Taking into account the current epidemiological data, including studies on catheter venography, the autoptic findings, and the relationship between CCSVI and both hypo-perfusion and cerebro-spinal fluid flow, we conclude that CCSVI can be definitively inserted among the medical entities. Research is still inconclusive in elucidating the CCSVI role in the pathogenesis of neurological disorders. The controversy between the vascular and the

  1. Mesenteric venous thrombosis: multidisciplinary therapeutic approach

    Directory of Open Access Journals (Sweden)

    Stefano Pieri

    2007-08-01

    Full Text Available Mesenteric venous thrombosis is a particular form of intestinal ischemia related to high mortality. The lack of a characteristic clinical picture often leads to a difficult diagnostic and therapeutic classification. We report the case of a young woman, using estrogenic and progestinic oral therapy, affected by a severe form of mesenteric thrombosis and complicated by segmental post ischemic stenosis of small intestine.

  2. A Genetical approach to deep venous thrombosis

    OpenAIRE

    Yavuz, Celal

    2012-01-01

    Deep venous thrombosis (DVT) is a common disorder that frequently occurs after surgical procedures and trauma and in the presence of cancer or immobilization conditions. However, it can also develop without any of these predisposing factors. This condition directs the researcher's enquiry to investigating the basis of organismal thrombotic predisposition. The common prothrombotic genetic mutations include factor V Leiden, factor II G20210 A, plasminogen activator inhibitor-1, prot...

  3. A genetical approach to deep venous thrombosis

    OpenAIRE

    Celal Yavuz

    2012-01-01

    Deep venous thrombosis (DVT) is a common disorderthat frequently occurs after surgical procedures andtrauma and in the presence of cancer or immobilizationconditions. However, it can also develop without any ofthese predisposing factors. This condition directs theresearcher’s enquiry to investigating the basis of organismalthrombotic predisposition. The common prothromboticgenetic mutations include factor V Leiden, factor IIG20210 A, plasminogen activator inhibitor-1, prothrombinA20210, and f...

  4. Developmental venous anomaly in the newborn brain

    Energy Technology Data Exchange (ETDEWEB)

    Horsch, S. [Erasmus MC-Sophia Children' s Hospital, Department of Neonatology, Rotterdam (Netherlands); Helios Klinikum Berlin-Buch, Department of Neonatology, Berlin (Germany); Govaert, P. [Erasmus MC-Sophia Children' s Hospital, Department of Neonatology, Rotterdam (Netherlands); Cowan, F.M. [Hammersmith Hospital, Department of Paediatrics, Imperial College Healthcare NHS Trust, London (United Kingdom); Benders, M.J.N.L.; Groenendaal, F.; Vries, L.S. de [University Medical Centre Utrecht, Wilhelmina Children' s Hospital, Department of Neonatology, Utrecht (Netherlands); Lequin, M.H. [Erasmus MC/Sophia Children' s Hospital, Department of Paediatric Radiology, Rotterdam (Netherlands); Saliou, G. [University Hospital, Department of Neuroradiology, Le Kremlin-Bicetre (France)

    2014-07-15

    Cerebral developmental venous anomaly (DVA) is considered a benign anatomical variant of parenchymal venous drainage; it is the most common vascular malformation seen in the adult brain. Despite its assumed congenital origin, little is known about DVA in the neonatal brain. We report here the first cohort study of 14 neonates with DVA. Fourteen infants (seven preterm) with DVA diagnosed neonatally using cranial ultrasound (cUS) and magnetic resonance imaging (MRI) from three tertiary neonatal units over 14 years are reviewed. DVA was first detected on cUS in 6 and on MRI in 8 of the 14 infants. The cUS appearances of DVA showed a focal fairly uniform area of increased echogenicity, often (86 %) adjacent to the lateral ventricle and located in the frontal lobe (58 %). Blood flow in the dilated collector vein detected by Doppler ultrasound (US) varied between cases (venous flow pattern in ten and arterialized in four). The appearance on conventional MRI was similar to findings in adults. Serial imaging showed a fairly constant appearance to the DVAs in some cases while others varied considerably regarding anatomical extent and flow velocity. This case series underlines that a neonatal diagnosis of DVA is possible with carefully performed cUS and MRI and that DVA tends to be an incidental finding with a diverse spectrum of imaging appearances. Serial imaging suggests that some DVAs undergo dynamic changes during the neonatal period and early infancy; this may contribute to why diagnosis is rare at this age. (orig.)

  5. Developmental venous anomaly in the newborn brain.

    Science.gov (United States)

    Horsch, S; Govaert, P; Cowan, F M; Benders, M J N L; Groenendaal, F; Lequin, M H; Saliou, G; de Vries, L S

    2014-07-01

    Cerebral developmental venous anomaly (DVA) is considered a benign anatomical variant of parenchymal venous drainage; it is the most common vascular malformation seen in the adult brain. Despite its assumed congenital origin, little is known about DVA in the neonatal brain. We report here the first cohort study of 14 neonates with DVA. Fourteen infants (seven preterm) with DVA diagnosed neonatally using cranial ultrasound (cUS) and magnetic resonance imaging (MRI) from three tertiary neonatal units over 14 years are reviewed. DVA was first detected on cUS in 6 and on MRI in 8 of the 14 infants. The cUS appearances of DVA showed a focal fairly uniform area of increased echogenicity, often (86 %) adjacent to the lateral ventricle and located in the frontal lobe (58 %). Blood flow in the dilated collector vein detected by Doppler ultrasound (US) varied between cases (venous flow pattern in ten and arterialized in four). The appearance on conventional MRI was similar to findings in adults. Serial imaging showed a fairly constant appearance to the DVAs in some cases while others varied considerably regarding anatomical extent and flow velocity. This case series underlines that a neonatal diagnosis of DVA is possible with carefully performed cUS and MRI and that DVA tends to be an incidental finding with a diverse spectrum of imaging appearances. Serial imaging suggests that some DVAs undergo dynamic changes during the neonatal period and early infancy; this may contribute to why diagnosis is rare at this age.

  6. Can developmental venous anomalies cause seizures?

    Science.gov (United States)

    Dussaule, Claire; Masnou, Pascal; Nasser, Ghaïdaa; Archambaud, Frédérique; Cauquil-Michon, Cécile; Gagnepain, Jean-Paul; Bouilleret, Viviane; Denier, Christian

    2017-12-01

    Developmental venous anomalies (DVAs) are congenital anatomical variants of normal venous drainage of normal brain. Although DVAs are often discovered on the occasion of a seizure, their involvement in epilepsy is poorly studied. Our objective was to determine whether DVA can cause seizures, in the cases where there is no associated lesion, including no cavernoma or dysplasia. Based on clinical history, cerebral MRI, EEG recording, and 18 F-FDG PET, we report 4 patients with DVA revealed by seizures. The first patient had a convulsive seizure caused by a hemorrhagic infarction due to thrombosis of her DVA. The second patient had a left temporo-parietal DVA next to a nonspecific lesion, possibly a sequelae of a venous infarction. The last two patients disclosed an isolated and uncomplicated DVA with a concordant epileptic focus confirmed on ictal video EEG recording. We reviewed literature and identified 21 other published cases of seizures caused by complications of a DVA and 9 patients that may have a direct link between epilepsy and an isolated and uncomplicated DVA. Seizures are linked to a DVA in two main situations: presence of an associated epileptogenic lesion, such as cavernoma or dysplasia, and occurrence of a complication of the DVA. Before concluding that a seizure is caused by a DVA, it is essential to perform full MRI protocols to search them. It remains rare and uncertain that isolated and uncomplicated DVA can cause seizures. In this last situation, physiopathological processes are probably different in each patient.

  7. Venous access: options, approaches and issues

    Energy Technology Data Exchange (ETDEWEB)

    Asch, M.R. [Univ. of Toronto, Mount Sinai Hospital, Dept. of Medical Imaging, Toronto, Ontario (Canada)

    2001-06-01

    Venous access is an essential part of medical practice. It is needed to obtain blood samples to make the diagnosis and to administer fluids or medicines as part of treatment. Although relatively new in the history of medicine, the placement and maintenance of the various venous access devices now occupies a significant portion of many vascular and interventional radiology practices. Thus, it is important to have a thorough understanding of these devices and their uses. The first long-term venous access devices were used in 1973. These were placed via a surgical cut-down on the subclavian vein. In 1982, the first subcutaneous implantable ports were described. These procedures were initially performed by surgeons, but over the last 5-10 years, both the insertion and management of these devices has shifted to interventional radiologists. Peripherally inserted central catheter (PICC) lines have almost completely supplanted the use of standard central lines (Fig. 1). A number of factors have facilitated this - namely, ready and less expensive room access, outpatient procedure and radiologists' accessibility and familiarity with image-guidance procedures and catheters and guide wires. (author)

  8. Incidence of central venous catheter hub contamination.

    Science.gov (United States)

    Holroyd, Julie L; Vasilopoulos, Terrie; Rice, Mark J; Rand, Kenneth H; Fahy, Brenda G

    2017-06-01

    To investigate microorganisms causing central venous catheter contamination and how this contamination differs across different catheter metrics. After obtaining IRB approval and informed consent, 830 cultures were prospectively obtained from 45 ICU patients with central venous catheter or peripherally inserted central catheter. Bacterial colonies were identified by mass spectrometry. Bacterial contamination of central catheter hubs occurred 44% of the time in this study in the ICU setting. Coagulase-positive staphylococci cultures had higher median (±interquartile range) CFUs (12±232) versus coagulase-negative (3±10) and other bacteria (1±3; Pcentral venous pressure monitoring connections (25.8% vs. 7.1% without). Internal jugular sites (10.0% vs. 2.7% femoral, 6.2% PICC, P=0.031) and medial lumens of triple lumen catheters (11.9% vs. 5.6% distal, 7.0% proximal, P=0.049) had increased incidence of higher bacteria loads (>15 CFUs). This study found a high incidence of central access catheter hub bacterial contamination, which correlated with positive blood cultures in 2 of 3 total bacteremia cases identified in the 45 patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. A new GTD slope diffraction coefficient for plane wave illumination of a wedge

    DEFF Research Database (Denmark)

    Lumholt, Michael; Breinbjerg, Olav

    1997-01-01

    Two wedge problems including slope diffraction are solved: one in which the incident field is a non-uniform plane wave, and one in which it is an inhomogeneous plane wave. The two solutions lead to the same GTD slope diffraction coefficient. This coefficient reveals the existence of a coupling...

  10. A Novel Continuous Extrusion Process to Fabricate Wedge-Shaped Light Guide Plates

    Directory of Open Access Journals (Sweden)

    Wen-Tse Hsiao

    2013-01-01

    Full Text Available Backlight modules are key components in thin-film transistor liquid crystal displays (TFT-LCD. Among the components of a backlight module, the light guide plate (LGP plays the most important role controlling the light projected to the eyes of users. A wedge-shaped LGP, with its asymmetrical structure, is usually fabricated by an injection proces, but the fabrication time of this process is long. This study proposes a continuous extrusion process to fabricate wedge-shaped LGPs. This continuous process has advantages for mass production. Besides a T-die and rollers, this system also has an in situ monitor of the melt-bank that forms during the extrusion process, helping control the plate thickness. Results show that the melt bank has a close relationship with the plate thickness. The temperature of the bottom heater and roller was adjusted to reduce the surface deformation of the wedge-shaped plate. This continuous extrusion system can successfully manufacture wedge-shaped LGPs for mass production.

  11. Non-invasive assessment of pulmonary capillary wedge pressure in the elderly by the Valsalva manoeuvre

    NARCIS (Netherlands)

    Remmen, Johannes Jacobus

    2006-01-01

    Heart failure (HF) is primarily a disorder of the elderly. However, in the elderly, physical examination and radiographic methods are not accurate in the diagnosis of HF. Pulmonary capillary wedge pressure (PCWP) provides an estimate of cardiac filling pressure and can be used to diagnose HF.

  12. Interaction of light with a metal wedge: the role of diffraction in shaping energy flow.

    Science.gov (United States)

    Xi, Yonggang; Jung, Yun Suk; Kim, Hong Koo

    2010-02-01

    When a light wave hits a metal wedge structure, the metal surfaces respond to the incident light by generating both free-space and surface-bound waves. Here we present a physical model that elucidates electromagnetic interactions of an incoming planar wave with a simple semi-infinite 90 degrees metal wedge. We show that a metal wedge structure possesses an intrinsic capability of directing the incident power around the corner into the forward direction. Interplay of the boundary diffraction wave and the incident and reflection waves in the near field region of a metal corner is found to form a basis of the funneling phenomena that are commonly observed in metal nanoslit structures. Theory and experiment reveal that the incident wave propagating parallel to the sidewall destructively interferes with the boundary diffraction wave forming a depleted-energy-flow region along the glancing angle direction. A physical understanding of various electromagnetic phenomena associated with a metal wedge structure confirms rich potential of the simple structure as an elemental building block of complex metal nanostructures.

  13. NOTE: Dosimetric characteristics of dynamic wedged fields: a Monte Carlo study

    Science.gov (United States)

    Shih, Rompin; Li, X. Allen; Hsu, Wen-Lin

    2001-12-01

    We have developed a Monte Carlo (MC) technique using the EGS4/BEAM system to calculate dosimetric characteristics of dynamic wedges (DW) for photon beam radiotherapy. The simulation of DW was accomplished by weighting the history numbers of the electrons, which are incident on the target in accordance with the segmented treatment table. Calculations were performed for DW with wedge angles ranging from 15° to 60° as well as for open fields with different field sizes for both 6 and 18 MV beams. The MC-calculated percentage depth dose (PDD) and beam profiles agreed with the measurements within +/-2% (of the dose maximum along the beam axis) or +/-2 mm in high dose gradient region. The DW slightly affects energy spectra of photons and contaminating electrons. These slight changes have no significant effects on PDD as compared to the open field. The MC-calculated dynamic wedge factors agree with the measurements within +/-2%. The MC method enables us to provide more detailed beam characteristics for DW fields than a measurement method. This beam characteristic includes photon energy spectra, mean energy, spectra of contaminating electrons and effects of moving jaw on off-axis beam quality. These data are potentially important for treatment planning involving dynamic wedges.

  14. Application of Orthopedic Dual Sliding Compression Plate (ODSCP) in High Medial Tibial Open Wedge Osteotomies.

    Science.gov (United States)

    Samani, Seyed Salman; Kachooei, Amir Reza; Ebrahimzadeh, Mohammad Hosein; Omidi Kashani, Farzad; Mahdavian Naghashzargar, Reza; Razi, Shiva

    2013-04-01

    Angular deformities about the knee are one of the common disorders. High Tibial osteotomy is a way of correcting the deformity. Although the general agreement is focused toward the open wedge technique, discussion about the type of device is a subject to debate. This current study has attempted to evaluate the results of Orthopedic Dual Sliding Compression Plate (ODSCP) in high medial open wedge osteotomies of the tibia. In this cross-sectional study, 16 patients with genuvarum undergone high medial tibial open wedge osteotomy and fixed by Orthopedic Dual Sliding Compression Plate. At the time of the last follow up visit, Lysholm score was gathered. The mean follow-up time was 9.33 ± 1.87 month. The average age was 45.13 ± 7.25 years. Three patients were male and 13 patients were female. The lysholm score showed a significant difference before and after surgery. The ODSCP has many advantages over the other type of plates. It can help the surgeon to operate with a relaxed mind and it is advisable for high tibial medial open wedge osteotomies.

  15. In situ spatiotemporal measurements of the detailed azimuthal substructure of the substorm current wedge

    DEFF Research Database (Denmark)

    Forsyth, C.; Fazakerley, A. N.; Rae, I. J.

    2014-01-01

    The substorm current wedge (SCW) is a fundamental component of geomagnetic substorms. Models tend to describe the SCW as a simple line current flowing into the ionosphere toward dawn and out of the ionosphere toward dusk, linked by a westward electrojet. We use multispacecraft observations from p...

  16. Numerical Simulation and Experimental Validation of an Integrated Sleeve-Wedge Anchorage for CFRP Rods

    DEFF Research Database (Denmark)

    Schmidt, Jacob Wittrup; Smith, Scott T.; Täljsten, Björn

    2011-01-01

    The tensioning of carbon fibre-reinforced polymer (CFRP) rods for prestressed concrete applications or post-tensioning repair and strengthening has met with mixed success. This is primarily due to limitations inherent in the use of traditional wedge anchors typically used for steel tendons...

  17. On the role of lateral waves in the radiation from the dielectric wedge

    DEFF Research Database (Denmark)

    Balling, Peter

    1973-01-01

    The field on the dielectric wedge is approximated by a plane-wave expansion as in [1]. Contributions from this solution to both the surface field and the radiation field are examined. Finally, an experimental radiation field is compared with the plane-wave solution and with a geometric...

  18. Revision of the venous clinical severity score: venous outcomes consensus statement: special communication of the American Venous Forum Ad Hoc Outcomes Working Group.

    Science.gov (United States)

    Vasquez, Michael A; Rabe, Eberhard; McLafferty, Robert B; Shortell, Cynthia K; Marston, William A; Gillespie, David; Meissner, Mark H; Rutherford, Robert B

    2010-11-01

    In response to the need for a disease severity measurement, the American Venous Forum committee on outcomes assessment developed the Venous Severity Scoring system in 2000. There are three components of this scoring system, the Venous Disability Score, the Venous Segmental Disease Score, and the Venous Clinical Severity Score (VCSS). The VCSS was developed from elements of the CEAP classification (clinical grade, etiology, anatomy, pathophysiology), which is the worldwide standard for describing the clinical features of chronic venous disease. However, as a descriptive instrument, the CEAP classification responds poorly to change. The VCSS was subsequently developed as an evaluative instrument that would be responsive to changes in disease severity over time and in response to treatment. Based on initial experiences with the VCSS, an international ad hoc working group of the American Venous Forum was charged with updating the instrument. This revision of the VCSS is focused on clarifying ambiguities, updating terminology, and simplifying application. The specific language of proven quality-of-life instruments was used to better address the issues of patients at the lower end of the venous disease spectrum. Periodic review and revision are necessary for generating more universal applicability and for comparing treatment outcomes in a meaningful way. Copyright © 2010 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  19. Modeling 3-D flow in the mantle wedge with complex slab geometries: Comparisons with seismic anisotropy

    Science.gov (United States)

    Kincaid, C. R.; MacDougall, J. G.; Druken, K. A.; Fischer, K. M.

    2010-12-01

    Understanding patterns in plate scale mantle flow in subduction zones is key to models of thermal structure, dehydration reactions, volatile distributions and magma generation and transport in convergent margins. Different patterns of flow in the mantle wedge can generate distinct signatures in seismological observables. Observed shear wave fast polarization directions in several subduction zones are inconsistent with predictions of simple 2-D wedge corner flow. Geochemical signatures in a number of subduction zones also indicate 3-D flow and entrainment patterns in the wedge. We report on a series of laboratory experiments on subduction driven flow to characterize spatial and temporal variability in 3-D patterns in flow and shear-induced finite strain. Cases focus on how rollback subduction, along-strike dip changes in subducting plates and evolving gaps or tears in subduction zones control temporal-spatial patterns in 3-D wedge flow. Models utilize a glucose working fluid with a temperature dependent viscosity to represent the upper 2000 km of the mantle. Subducting lithosphere is modeled with two rubber-reinforced continuous belts. Belts pass around trench and upper/lower mantle rollers. The deeper rollers can move laterally to allow for time varying dip angle. Each belt has independent speed control and dip adjustment, allowing for along-strike changes in convergence rate and the evolution of slab gaps. Rollback is modeled using a translation system to produce either uniform and asymmetric lateral trench motion. Neutral density finite strain markers are distributed throughout the fluid and used as proxies for tracking the evolution of anisotropy through space and time in the evolving flow fields. Particle image velocimetry methods are also used to track time varying 3-D velocity fields for directly calculating anisotropy patterns. Results show that complex plate motions (rollback, steepening) and morphologies (gaps) in convergent margins produce flows with

  20. Cumulative effects of climate change and ice-wedge degradation, Prudhoe Bay oilfield Alaska

    Science.gov (United States)

    Walker, D. A.; Kanevskiy, M. Z.; Shur, Y.; Raynolds, M. K.; Buchhorn, M.

    2016-12-01

    Development of Arctic oil & gas resources requires extensive networks of roads, pipelines and other forms of infrastructure. The Prudhoe Bay Oilfield is the largest Arctic oilfield in North America with a long, well-documented history. In a previous publication we analyzed the historical record of high-resolution aerial photos to document the long-term changes to infrastructure extent (1949-2010) for the entire oilfield, and an integrated-geoecological-historical-change-mapping (IGHCM) approach to document terrain changes within 22-km2 areas of the oilfield. We reported the recent widespread expansion of thermokarst, starting in about 1989. Here we examine the annual air-photo record to better pinpoint the years of major change. We also conducted detailed field studies of roadside changes using topographic surveys and soil, vegetation and ice-wedge coring studies. Both sites exhibit extensive ice-wedge degradation that is caused by a combination of a long-term warming trend a series of exceptionally warm summers, and infrastructure-related factors that melted the tops of ice wedges. Near-road thermokarst is enhanced by warmer soils associated with road dust, roadside flooding, near-road pipelines, communication cables, and altered snow regimes. These strongly affect roadside ecosystems and the infrastructure itself. Changes to ecosystems include altered hydrology with the drying of polygon centers and the formation of well-developed high-centered polygons occurs in some areas. Other areas develop extensive flooding and erosion of ice-wedge troughs. An unexpected result of flooding is the stabilization of ice-wedge degradation in some areas because the increased productivity of sedges in the flooded areas is producing large amounts of organic material that protects the tops of ice wedges from further degradation. The large increases in productivity in roadside areas also attract large flocks of waterfowl. Changes to the soils with the addition of thick layers of

  1. External jugular venous pressure as an alternative to conventional central venous pressure in right lobe donor hepatectomies.

    Science.gov (United States)

    Abdullah, Mohamed Hussein; Soliman, Hossam El Deen; Morad, Wessam Saber

    2011-12-01

    Many centers have adopted central vein cannulation both for central venous pressure monitoring and fluid administration for right hepatectomy in living-liver donors. However, use of central venous catheters is associated with adverse events that are hazardous to patients and expensive to treat. This study sought to examine the use of external jugular venous pressure as an alternative to conventional central venous pressure in right lobe donor hepatectomies Forty ASA grade I adult living liver-donors without a known history of significant cardiac or pulmonary diseases were enrolled in this prospective observational study. Paired measurement of venous pressures (external jugular venous pressure and internal jugular venous pressure) were taken at the following times: after induction of anesthesia, 30 minutes after skin incision, during right lobe mobilization (every 15 minutes), during hepatic transaction (every 15 minutes), after right lobe resection (every 15 minutes), and after abdominal closure. Paired measurements were equal in 47.5%, 53.5%, 61.5%, 46.3%, and 52.5% for after induction, after skin incision, right lobe mobilization, right lobe transection, after resection, and before abdominal closure periods. However, all measurements were within acceptable limits of bias measurements (± 2 mm Hg). Central venous pressure catheter placement can be avoided and replaced by a less-invasive method such as external jugular venous pressure (which gave an acceptable estimate of central venous pressure in all phases of right lobe resection) in living-donor liver transplant and allowed equivalent monitor even during fluid restriction phases.

  2. Simulation of Climate Control On Tectonic Mass-transfer In Bivergent Orogenic Wedges ­ Insights From Scaled Sandbox Models.

    Science.gov (United States)

    Hoth, S.; Adam, J.; Kukowski, N.; Oncken, O.

    Orogenic wedges are expressions of dynamic equilibrium between tectonic and grav- itational stresses. Thus, surficial mass transport by climate-driven erosion changes the morphology of, and the state of stress within, the orogenic wedge. Here, we suggest that the orogenic wedge adjusts itself to the new stress conditions, inducing changes in morphology, which may modify the pre-existing drainage pattern, and therefore change also the erosion rate. Depending on the amount of vertical alteration in wedge morphology the regional climate is modified, which again may lead to a different ero- sion rate. The aim of this study is to describe qualitatively and quantitatively how different ero- sion rates and their 2D lateral distribution influences the mass-transport mode in col- lisional orogens, using scaled sandbox-experiments. The advantages of analogue sim- ulation are (i) a more detailed structural resolution, (ii) a direct observation of strain localisation and fault propagation and (iii) an easy way of applying erosion at any given point through time. The models presented here were run in a 2D shearbox with two converging sand lay- ers which build up a bivergent sand-orogen. A thin glass-bead layer which simulates a mid-level detachment was incorporated to allow frontal and basal accretion. Us- ing a vacuum cleaner, incremental erosion, which decreases linearly from the top of the sand-orogen to the toe of either the pro-wedge or retro-wedge, was simulated. A friction-controlled elastic/plastic rheology with strain hardening and softening is used to simulate upper crustal rock deformation. Our aim is to elucidate: (i) The in- fluence of different modes of distribution of erosion rates on the tectonically-driven mass transfer in orogenic belts. (ii) The control of erosion rates on tectonic style in orogenic wedges, i.e. frontal versus basal accretion. (iii) The time and length scales at which climatic and tectonic forces interact. (iv) The way with which such

  3. HIV-ASSOCIATED VENOUS THROMBOEMBOLISM

    Directory of Open Access Journals (Sweden)

    Michele Bibas

    2011-01-01

    ="false" Priority="21" SemiHidden="false" UnhideWhenUsed="false" QFormat="true" Name="Intense Emphasis" />

    HIV infection has been recognized as a prothrombotic condition and this association has now been proven by a large number of studies with a reported VTE frequency among HIV-infected patients ranging from 0.19% to 7,63 %/year. HIV infection is associated with a two to tenfold increased risk of venous thrombosis in comparison with a general population of the same age. Some r

  4. The Effect of the Vertex Angles of Wedged Indenters on Deformation during Nanoindentation

    Directory of Open Access Journals (Sweden)

    Xiaowen Hu

    2017-12-01

    Full Text Available In order to study the effect of the angle of wedged indenters during nanoindentation, indenters with half vertex angles of 60°, 70° and 80° are used for the simulations of nanoindentation on FCC aluminum (Al bulk material by the multiscale quasicontinuum method (QC. The load-displacement responses, the strain energy-displacement responses, and hardness of Al bulk material are obtained. Besides, atomic configurations for each loading situation are presented. We analyze the drop points in the load-displacement responses, which correspond to the changes of microstructure in the bulk material. From the atom images, the generation of partial dislocations as well as the nucleation and the emission of perfect dislocations have been observed with wedged indenters of half vertex angles of 60° and 70°, but not 80°. The stacking faults move beneath the indenter along the direction [ 1 1 ¯ 0 ] . The microstructures of residual displacements are also discussed. In addition, hardness of the Al bulk material is different in simulations with wedged indenters of half vertex angles of 60° and 70°, and critical hardness in the simulation with the 70° indenter is bigger than that with the 60° indenter. The size effect of hardness in plastic wedged nanoindentation is observed. There are fewer abrupt drops in the strain energy-displacement response than in the load-displacement response, and the abrupt drops in strain energy-displacement response reflect the nucleation of perfect dislocations or extended dislocations rather than partial dislocations. The wedged indenter with half vertex angle of 70° is recommended for investigating dislocations during nanoindentation.

  5. Role of ground ice dynamics and ecological feedbacks in recent ice wedge degradation and stabilization

    Science.gov (United States)

    Mark Torre Jorgenson,; Mikhail Kanevskiy,; Yuri Shur,; Natalia Moskalenko,; Dana Brown,; Wickland, Kimberly P.; Striegl, Robert G.; Koch, Joshua C.

    2015-01-01

    Ground ice is abundant in the upper permafrost throughout the Arctic and fundamentally affects terrain responses to climate warming. Ice wedges, which form near the surface and are the dominant type of massive ice in the Arctic, are particularly vulnerable to warming. Yet processes controlling ice wedge degradation and stabilization are poorly understood. Here we quantified ice wedge volume and degradation rates, compared ground ice characteristics and thermal regimes across a sequence of five degradation and stabilization stages and evaluated biophysical feedbacks controlling permafrost stability near Prudhoe Bay, Alaska. Mean ice wedge volume in the top 3 m of permafrost was 21%. Imagery from 1949 to 2012 showed thermokarst extent (area of water-filled troughs) was relatively small from 1949 (0.9%) to 1988 (1.5%), abruptly increased by 2004 (6.3%) and increased slightly by 2012 (7.5%). Mean annual surface temperatures varied by 4.9°C among degradation and stabilization stages and by 9.9°C from polygon center to deep lake bottom. Mean thicknesses of the active layer, ice-poor transient layer, ice-rich intermediate layer, thermokarst cave ice, and wedge ice varied substantially among stages. In early stages, thaw settlement caused water to impound in thermokarst troughs, creating positive feedbacks that increased net radiation, soil heat flux, and soil temperatures. Plant growth and organic matter accumulation in the degraded troughs provided negative feedbacks that allowed ground ice to aggrade and heave the surface, thus reducing surface water depth and soil temperatures in later stages. The ground ice dynamics and ecological feedbacks greatly complicate efforts to assess permafrost responses to climate change.

  6. Structure of the Orogenic Wedge in the Bhutan Himalaya: First Results from the GANSSER Seismic Experiment

    Science.gov (United States)

    Singer, J.; Hetényi, G.; Diehl, T.; Kissling, E. H.

    2014-12-01

    In the Eastern Himalaya, the structure of the orogenic wedge above the subducting Indian lithosphere and even the Moho topography of the latter are poorly constrained at present. The Main Himalayan Thrust (MHT) is considered a crustal-scale detachment that marks the plate boundary separating the bottom of the orogenic wedge from the top of the Indian crust. In western and central Himalaya portions of the MHT have been imaged by receiver functions (RF) from the surface near the foothills of the Himalayan front range to mid-crustal depths. In Bhutan, however, the MHT and other major thrust geometries at depth remain a matter of debate, without direct geophysical image. Furthermore, earthquake activity in Bhutan seems to be significantly lower compared to most other parts of the Himalayan arc and there appears to be a lack of great earthquakes. This lower level of seismicity could be related to a more ductile deformation in the orogenic wedge, or, alternatively, result from a currently locked situation of the thrust system. In this work, we use data of a densely spaced, temporary seismic network in Bhutan (GANSSER experiment) to determine lithospheric and intra-crustal discontinuities in the Eastern Himalaya with RF complemented by seismic velocities derived from simultaneous inversion of local earthquake data. Along two south-north profiles across the Himalayan range in eastern and western Bhutan the geometry of the dipping Indian Moho is defined by migrated RF images including a dip correction. Based on the characteristics of the RF, the dip and strike of the Moho is independently defined and the occurrence of intra-crustal conversion interfaces like the MHT are mapped across the orogenic wedge. In combination with the geometry of the intra-crustal seismic structure, we use the seismic velocities and the hypocenters of local earthquakes to discuss the predominant deformation type in the orogenic wedge in Bhutan and the potential for large earthquakes in this region

  7. Compression for preventing recurrence of venous ulcers.

    Science.gov (United States)

    Nelson, E Andrea; Bell-Syer, Sally E M

    2014-09-09

    Up to 1% of adults will have a leg ulcer at some time. The majority of leg ulcers are venous in origin and are caused by high pressure in the veins due to blockage or weakness of the valves in the veins of the leg. Prevention and treatment of venous ulcers is aimed at reducing the pressure either by removing/repairing the veins, or by applying compression bandages/stockings to reduce the pressure in the veins.The majority of venous ulcers heal with compression bandages, however ulcers frequently recur. Clinical guidelines therefore recommend that people continue to wear compression, usually in the form of hosiery (tights, stockings, socks) after their ulcer heals, to prevent recurrence. To assess the effects of compression (socks, stockings, tights, bandages) in preventing the recurrence of venous ulcers. If compression does prevent ulceration compared with no compression, then to identify whether there is evidence to recommend particular levels of compression (high, medium or low, for example), types of compression, or brands of compression to prevent ulcer recurrence after healing. For this second update we searched The Cochrane Wounds Group Specialised Register (searched 4 September 2014) which includes the results of regular searches of MEDLINE, EMBASE and CINAHL; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 8). Randomised controlled trials (RCTs)evaluating compression bandages or hosiery for preventing the recurrence of venous ulcers. Two review authors undertook data extraction and risk of bias assessment independently. Four trials (979 participants) were eligible for inclusion in this review. One trial in patients with recently healed venous ulcers (n = 153) compared recurrence rates with and without compression and found that compression significantly reduced ulcer recurrence at six months (Risk ratio (RR) 0.46, 95% CI 0.27 to 0.76).Two trials compared high-compression hosiery (equivalent to UK class 3) with

  8. Epidemiology of the contraceptive pill and venous thromboembolism.

    Science.gov (United States)

    Hannaford, Philip C

    2011-02-01

    Current users of combined oral contraceptives have an increased risk of venous thromboembolism. The risk appears to be higher during the first year of use and disappears rapidly once oral contraception is stopped. There is a strong interaction between hereditary defects of coagulation, combined oral contraceptive use and venous thromboembolism. Nevertheless, the routine screening of women before they use combined oral contraception is not recommended. Venous thromboembolism seems to be higher in overweight users, and after air, and possibly other forms of, travel. Both the oestrogen and progestogen content of combined oral contraceptives have been implicated in differences in venous thrombotic risk between products. Even if real, the absolute difference in risk between products is small, because the background incidence of venous thromboembolism in young women is low. All currently available combined oral contraceptives are safe. Progestogen-only oral contraceptives are not associated with an increased risk of venous thromboembolism. © 2011 Elsevier Ltd. All rights reserved.

  9. Lack of variation in venous tone potentiates vasovagal syncope.

    Science.gov (United States)

    Hargreaves, A D; Muir, A L

    1992-01-01

    OBJECTIVE--To investigate the peripheral venous response to head up tilting in malignant vasovagal syndrome. PATIENTS--31 Patients with unexplained syncope or dizziness referred from the cardiology department. METHODS--Changes in calf venous volume were studied by a radionuclide technique during 45 degrees head up tilt testing. RESULTS--During tilt testing six patients became syncopal but 25 were symptom free. The syncopal group had greater increases in calf venous volume after the change in posture and perhaps more importantly considerably less variability in the venous volume during the tilted period. CONCLUSIONS--The venous response was different in the syncopal patients. The lack of response of the peripheral venous circulation to changes in the central circulation may be responsible for triggering the Bezold-Jarisch reflex and malignant vasovagal syncope. PMID:1622700

  10. Core content for training in venous and lymphatic medicine.

    Science.gov (United States)

    Zimmet, Steven E; Min, Robert J; Comerota, Anthony J; Meissner, Mark H; Carman, Teresa L; Rathbun, Suman W; Jaff, Michael R; Wakefield, Thomas W; Feied, Craig F

    2014-10-01

    The major venous societies in the United States share a common mission to improve the standards of medical practitioners, the educational goals for teaching and training programs in venous disease, and the quality of patient care related to the treatment of venous disorders. With these important goals in mind, a task force made up of experts from the specialties of dermatology, interventional radiology, phlebology, vascular medicine, and vascular surgery was formed to develop a consensus document describing the Core Content for venous and lymphatic medicine and to develop a core educational content outline for training. This outline describes the areas of knowledge considered essential for practice in the field, which encompasses the study, diagnosis, and treatment of patients with acute and chronic venous and lymphatic disorders. The American Venous Forum and the American College of Phlebology have endorsed the Core Content. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  11. Differences in wedge factor determination in air using a PMMA mini-phantom or a brass build-up cap.

    Science.gov (United States)

    Heukelom, S; Lanson, J H; Mijnheer, B J

    1997-12-01

    The head scatter dose contribution to the output of a treatment machine has been determined for an open and wedged 60Co gamma-ray beam and for open and wedged x-ray beams of 4, 8, and 16 MV. From those data wedge factor values "in air" have been deduced, expressed as the ratio of the dose to water, measured in air, for the situation with and without wedge, for the same number of monitor units (or treatment time for 60Co). The measurements have been performed using a polymethyl-metacrylate (PMMA) and a graphite-walled ionization chamber inserted in a brass build-up cap and in a PMMA mini-phantom, respectively. Absolute wedge factor values deduced with both detector systems and based on the ratio of ionization chamber readings, differ for the investigated photon beams, up to 3.5% for the 4 MV x-ray beam. The deviations results from the difference in composition between the detector materials and water and can be taken into account by conversion of the ionization chamber readings for both the open and wedged photon beams to the absorbed dose to water. For the brass build-up cap detector system the ratio of the conversion factors for the wedged and open beam changes the ratio of the ionization chamber readings up to about 3.6% for the 4 MV x-ray beam. For the mini-phantom the conversion factors for the wedged and open beam are almost equal for all photon beams. Consequently, for that system wedge factors based on ionization chamber readings or dose values are the same. With respect to the wedge factor variation with field size a somewhat larger increase has been determined for the 60Co and 4 MV photon beam using the brass build-up cap: about 1% for field sizes varying between 5 cm x 5 cm and 15 cm x 15 cm. This effect has to be related to an apparent more pronounced variation of the head scatter dose contribution with field size for the wedged photon beams if the brass build-up cap detection system is used. It can be concluded that determination of wedge factors "in

  12. [Venous thrombosis associated with central venous catheter use in patients with cancer].

    Science.gov (United States)

    Iglesias Rey, Leticia; Fernández Pérez, Isaura; Barbagelata López, Cristina; Rivera Gallego, Alberto

    2015-01-01

    The use of central venous catheters for various applications (administration of chemotherapy, blood products and others) in patients with cancer is increasingly frequent. The association between thrombosis and catheter use has been fully established but aspects such as its causes, diagnosis, prophylaxis and treatment have not. We describe a case of thrombosis in a patient with cancer treated with chemotherapy who carried a central venous catheter. We also perform a review of the risk factors, the role of the prophylaxis and the treatment. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

  13. Systematic review of topic treatment for venous ulcers

    OpenAIRE

    Borges, Eline Lima; Caliri, Maria Helena Larcher; Haas, Vanderlei José

    2007-01-01

    Venous ulcer patients can experience this situation for several years without achieving healing if treatment is inadequate. Evidence-based professional practice generates effective results for patients and services. This research aimed to carry out a systematic review to assess the most effective method to improve venous return and the best topic treatment for these ulcers. Studies were collected in eight databases, using the following descriptors: leg ulcer, venous ulcer and similar terms. T...

  14. Lack of variation in venous tone potentiates vasovagal syncope.

    OpenAIRE

    Hargreaves, A D; Muir, A L

    1992-01-01

    OBJECTIVE--To investigate the peripheral venous response to head up tilting in malignant vasovagal syndrome. PATIENTS--31 Patients with unexplained syncope or dizziness referred from the cardiology department. METHODS--Changes in calf venous volume were studied by a radionuclide technique during 45 degrees head up tilt testing. RESULTS--During tilt testing six patients became syncopal but 25 were symptom free. The syncopal group had greater increases in calf venous volume after the change in ...

  15. Factors associated with poor healing and recurrence of venous ulceration.

    Science.gov (United States)

    Labropoulos, Nicos; Wang, Eric D; Lanier, Steven T; Khan, Sami U

    2012-01-01

    Plastic surgeons are often approached for wound management and closure of chronic venous ulcers that fail to heal despite multimodal management. The authors present a retrospective analysis of a large series of venous ulcers to determine factors predicting nonhealing and recurrence. Consecutive patients with chronic venous ulcers (≥ 2-cm diameter) were examined for the presence of superficial, perforating, or deep venous disease, including reflux and/or obstruction. Treatment included compression, venous ligation, stripping, thermal ablation, sclerotherapy, and local wound care. Ulcers refractory to 6 months of treatment were defined as nonhealing ulcers. Data were analyzed for differences in baseline patient and ulcer characteristics and clinical course of nonhealing ulcers. Data were compared using Wilcoxon rank sum, chi-square, and Fisher's exact tests using Sigma Stat and SPSS, with α set at p ulcers in 127 patients. Factors associated with ulcer nonhealing included advanced age, increased body mass index, history of deep venous thrombosis, noncompliance with compression therapy, and large ulcer area. One hundred thirty-one of the ulcers (85.6 percent) healed within 6 months and 147 (96 percent) of the ulcers ultimately healed without the need for operative plastic surgical intervention. A thorough understanding of risks and expected clinical course is required for assessment of the nonhealing venous ulcer. The authors recommend identification and correction of underlying venous abnormality and a minimum of at least 6 months of compression and local wound care followed by reassessment of venous function before operative plastic surgical intervention should be considered. Risk, III.

  16. Venous ulcers of the lower limb: Where do we stand?

    Science.gov (United States)

    Chatterjee, Sasanka S.

    2012-01-01

    Venous ulcers are the most common ulcers of the lower limb. It has a high morbidity and results in economic strain both at a personal and at a state level. Chronic venous hypertension either due to primary or secondary venous disease with perforator paucity, destruction or incompetence resulting in reflux is the underlying pathology, but inflammatory reactions mediated through leucocytes, platelet adhesion, formation of pericapillary fibrin cuff, growth factors and macromolecules trapped in tissue result in tissue hypoxia, cell death and ulceration. Duplex scan with colour flow is the most useful investigation for venous disease supplying information about patency, reflux, effects of proximal and distal compression, Valsalva maneuver and effects of muscle contraction. Most venous disease can be managed conservatively by leg elevation and compression bandaging. Drugs of proven benefit in venous disease are pentoxifylline and aspirin, but they work best in conjunction with compression therapy. Once ulceration is chronic or the patient does not respond to or cannot maintain conservative regime, surgical intervention treating the underlying venous hypertension and cover for the ulcer is necessary. The different modalities like sclerotherapy, ligation and stripping of superficial varicose veins, endoscopic subfascial perforator ligation, endovenous laser or radiofrequency ablation have similar long-term results, although short-term recovery is best with radiofrequency and foam sclerotherapy. For deep venous reflux, surgical modalities include repair of incompetent venous valves or transplant or transposition of a competent vein segment with normal valves to replace a post-thrombotic destroyed portion of the deep vein. PMID:23162226

  17. Venous ulcers of the lower limb: Where do we stand?

    Directory of Open Access Journals (Sweden)

    Chatterjee S Sasanka

    2012-01-01

    Full Text Available Venous ulcers are the most common ulcers of the lower limb. It has a high morbidity and results in economic strain both at a personal and at a state level. Chronic venous hypertension either due to primary or secondary venous disease with perforator paucity, destruction or incompetence resulting in reflux is the underlying pathology, but inflammatory reactions mediated through leucocytes, platelet adhesion, formation of pericapillary fibrin cuff, growth factors and macromolecules trapped in tissue result in tissue hypoxia, cell death and ulceration. Duplex scan with colour flow is the most useful investigation for venous disease supplying information about patency, reflux, effects of proximal and distal compression, Valsalva maneuver and effects of muscle contraction. Most venous disease can be managed conservatively by leg elevation and compression bandaging. Drugs of proven benefit in venous disease are pentoxifylline and aspirin, but they work best in conjunction with compression therapy. Once ulceration is chronic or the patient does not respond to or cannot maintain conservative regime, surgical intervention treating the underlying venous hypertension and cover for the ulcer is necessary. The different modalities like sclerotherapy, ligation and stripping of superficial varicose veins, endoscopic subfascial perforator ligation, endovenous laser or radiofrequency ablation have similar long-term results, although short-term recovery is best with radiofrequency and foam sclerotherapy. For deep venous reflux, surgical modalities include repair of incompetent venous valves or transplant or transposition of a competent vein segment with normal valves to replace a post-thrombotic destroyed portion of the deep vein.

  18. Pregnancy-related venous thromboembolism and risk of occult cancer

    DEFF Research Database (Denmark)

    Veres, Katalin; Horváth-Puhó, Erzsébet; Ehrenstein, Vera

    2017-01-01

    The cancer risk during the first year after a pregnancy-related venous thromboembolism episode is higher than expected.An aggressive search for cancer in women with pregnancy-related venous thromboembolism is probably not warranted, due to low absolute risk.......The cancer risk during the first year after a pregnancy-related venous thromboembolism episode is higher than expected.An aggressive search for cancer in women with pregnancy-related venous thromboembolism is probably not warranted, due to low absolute risk....

  19. MRA for diagnosis of venous thromboembolism

    Energy Technology Data Exchange (ETDEWEB)

    Sostman, H. D. [Cornell University, Weill Medical College, Chair of Radiology, New York (United States)

    2001-12-01

    Direct imaging of pulmonary embolism (PE) and deep vein thrombosis (DVT) with CT, and potentially with MR, will continue to replace V/Q scintigraphy. Venous imaging with MR far detecting DVT is used in a few centers, and their published accuracy figures are impressive. Recent studies of MR pulmonary angiography for PE reported that sensitivity of MRA was 85-100%, specificity 95-96%, but this data must be confirmed in other centers and patient populations. MR has advantages compared with CT, which make it worthwhile to continue MR development. Ionizing radiation and iodinated contrast material are not used. Imaging the pulmonary arteries and then imaging whichever venous region is of clinical interest is practical in a single examination. Repeated examinations can be performed safely. New contrast materials will facilitate the practically and accuracy of the MR technique and perfusion imaging may increase sensitivity. MR also has disadvantages compared with CT. It does not image effectively the non-vascular compartment of the lungs. It is more expensive, patient monitoring is more cumbersome, and a routine technique, which embodies all of MR's potential advantages, has not been packaged and tested. Accordingly, helical CT is a realistic option in clinical management of patients with suspected PE in most centers, while clinical application of MR is limited to centers with appropriate MR expertise and technology. However, MR has a number of fundamental characteristics that make it potentially ideal modality for evaluating patients with suspected acute venous thromboembolic disease and further clinical research with MRA is warranted.

  20. 77 FR 24718 - Scientific Information Request on Chronic Venous Ulcers Treatments

    Science.gov (United States)

    2012-04-25

    ... Venous Ulcers Treatments AGENCY: Agency for Healthcare Research and Quality (AHRQ), HHS. ACTION: Request...) is seeking scientific information submissions from manufacturers of chronic venous ulcer treatment medical devices. Scientific information is being solicited to inform our Chronic Venous Ulcers: A...

  1. Direct oral anticoagulants and venous thromboembolism

    Directory of Open Access Journals (Sweden)

    Massimo Franchini

    2016-09-01

    Full Text Available Venous thromboembolism (VTE, consisting of deep vein thrombosis and pulmonary embolism, is a major clinical concern associated with significant morbidity and mortality. The cornerstone of management of VTE is anticoagulation, and traditional anticoagulants include parenteral heparins and oral vitamin K antagonists. Recently, new oral anticoagulant drugs have been developed and licensed, including direct factor Xa inhibitors (e.g. rivaroxaban, apixaban and edoxaban and thrombin inhibitors (e.g. dabigatran etexilate. This narrative review focusses on the characteristics of these direct anticoagulants and the main results of published clinical studies on their use in the prevention and treatment of VTE.

  2. Altered Venous Function during Long-Duration Spaceflights

    Directory of Open Access Journals (Sweden)

    Jacques-Olivier Fortrat

    2017-09-01

    Full Text Available Aims: Venous adaptation to microgravity, associated with cardiovascular deconditioning, may contribute to orthostatic intolerance following spaceflight. The aim of this study was to analyze the main parameters of venous hemodynamics with long-duration spaceflight.Methods: Venous plethysmography was performed on 24 cosmonauts before, during, and after spaceflights aboard the International Space Station. Venous plethysmography assessed venous filling and emptying functions as well as microvascular filtration, in response to different levels of venous occlusion pressure. Calf volume was assessed using calf circumference measurements.Results: Calf volume decreased during spaceflight from 2.3 ± 0.3 to 1.7 ± 0.2 L (p < 0.001, and recovered after it (2.3 ± 0.3 L. Venous compliance, determined as the relationship between occlusion pressure and the change in venous volume, increased during spaceflight from 0.090 ± 0.005 to 0.120 ± 0.007 (p < 0.01 and recovered 8 days after landing (0.071 ± 0.005, arbitrary units. The index of venous emptying rate decreased during spaceflight from −0.004 ± 0.022 to −0.212 ± 0.033 (p < 0.001, arbitrary units. The index of vascular microfiltration increased during spaceflight from 6.1 ± 1.8 to 10.6 ± 7.9 (p < 0.05, arbitrary units.Conclusion: This study demonstrated that overall venous function is changed during spaceflight. In future, venous function should be considered when developing countermeasures to prevent cardiovascular deconditioning and orthostatic intolerance with long-duration spaceflight.

  3. Radiographic signs of non-venous placement of intended central venous catheters in children

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Erin C. [Boston Children' s Hospital, Department of Radiology, Boston, MA (United States); Taylor, George A. [Boston Children' s Hospital, Department of Radiology, Boston, MA (United States); Harvard Medical School, Department of Radiology, Boston, MA (United States)

    2016-02-15

    Central venous catheters (CVCs) are commonly used in children, and inadvertent arterial or extravascular cannulation is rare but has potentially serious complications. To identify the radiographic signs of arterial placement of CVCs. We retrospectively reviewed seven cases of arterially malpositioned CVCs on chest radiograph. These cases were identified through departmental quality-assurance mechanisms and external consultation. Comparison of arterial cases was made with 127 age-matched chest radiographs with CVCs in normal, expected venous location. On each anteroposterior (AP) radiograph we measured the distance of the catheter tip from the right lateral border of the thoracic spine, and the angle of the vertical portion of the catheter relative to the midline. On each lateral radiograph we measured the angle of the vertical portion of each catheter relative to the anterior border of the thoracic spine. When bilateral subclavian catheters were present, the catheter tips were described as crossed, overlapping or uncrossed. On AP radiographs, arterially placed CVCs were more curved to the left, with catheter tip positions located farther to the left of midline than normal venous CVCs. When bilateral, properly placed venous catheters were present, all catheters crossed at the level of the superior vena cava (SVC). When one of the bilateral catheters was in arterial position, neither of the catheters crossed or the inter-catheter crossover distance was exaggerated. On lateral radiographs, there was a marked anterior angulation of the vertical portion of the catheter (mean angle 37 ± 15 standard deviation [SD] in arterial catheters versus 5.9 ± 8.3 SD in normally placed venous catheters). Useful radiographic signs suggestive of unintentional arterial misplacement of vascular catheters include leftward curvature of the vertical portion of the catheter, left-side catheter tip position, lack of catheter crossover on the frontal radiograph, as well as exaggerated

  4. Radiographic signs of non-venous placement of intended central venous catheters in children.

    Science.gov (United States)

    Taylor, Erin C; Taylor, George A

    2016-02-01

    Central venous catheters (CVCs) are commonly used in children, and inadvertent arterial or extravascular cannulation is rare but has potentially serious complications. To identify the radiographic signs of arterial placement of CVCs. We retrospectively reviewed seven cases of arterially malpositioned CVCs on chest radiograph. These cases were identified through departmental quality-assurance mechanisms and external consultation. Comparison of arterial cases was made with 127 age-matched chest radiographs with CVCs in normal, expected venous location. On each anteroposterior (AP) radiograph we measured the distance of the catheter tip from the right lateral border of the thoracic spine, and the angle of the vertical portion of the catheter relative to the midline. On each lateral radiograph we measured the angle of the vertical portion of each catheter relative to the anterior border of the thoracic spine. When bilateral subclavian catheters were present, the catheter tips were described as crossed, overlapping or uncrossed. On AP radiographs, arterially placed CVCs were more curved to the left, with catheter tip positions located farther to the left of midline than normal venous CVCs. When bilateral, properly placed venous catheters were present, all catheters crossed at the level of the superior vena cava (SVC). When one of the bilateral catheters was in arterial position, neither of the catheters crossed or the inter-catheter crossover distance was exaggerated. On lateral radiographs, there was a marked anterior angulation of the vertical portion of the catheter (mean angle 37 ± 15° standard deviation [SD] in arterial catheters versus 5.9 ± 8.3° SD in normally placed venous catheters). Useful radiographic signs suggestive of unintentional arterial misplacement of vascular catheters include leftward curvature of the vertical portion of the catheter, left-side catheter tip position, lack of catheter crossover on the frontal radiograph, as well as

  5. Orbital venous pattern in relation to extraorbital venous drainage and superficial lymphatic vessels in rats.

    Science.gov (United States)

    Maloveska, Marcela; Kresakova, Lenka; Vdoviakova, Katarina; Petrovova, Eva; Elias, Mario; Panagiotis, Artemiou; Andrejcakova, Zuzana; Supuka, Peter; Purzyc, Halina; Kissova, Viktoria

    2017-01-01

    The purpose of this study was to demonstrate the normal and variant anatomy of extraorbital and intraorbital venous drainage together with retroorbital communication, and determine the lymphatic drainage from the superficial orbital region with a potential outlet of lymphatic vessel into the venous bloodstream. The study of the venous system was carried out on 32 Wistar rats by using corrosion casts methods and radiography, while the lymphatic system was studied in 12 Wistar rats following ink injection. Superficially, orbital veins are connected with extraorbital veins running through angular vein of the eye and the superficial temporal vein, and via the pterygoid plexus with the maxillary vein, which provide readily accessible communication routes in the spread of infection. The extent of intraorbital and periorbital venous drainage was ensured by the dorsal and ventral external ophthalmic vein through the infraorbital vein, which together formed the principal part of the ophthalmic plexus. Venous drainage of the eyeball was carried out mainly by the vortex veins, ciliary veins and internal ophthalmic vein. The highest variability, first presented by differences in structural arrangement and formation of anastomoses, was observed within the ventral external ophthalmic vein (22 cases) and the medial vortex vein (10 cases). Four vortex veins, one vein in each quadrant of the eye, were observed in rats. The vortex vein located on the ventral side of the eyeball was occasionally found as two veins (in four cases) in the present study. The lymphatic vessel from the lower eyelid entered into the mandibular lymph centre, and from the upper eyelid entered into the superficial cervical lymph centre, but both drained into the deep cranial cervical lymph node. The direct entry of lymph entering the veins without passing through lymph nodes was not observed.

  6. Estimating effective wedge factor for enhanced dynamic wedge 2100CD a Varian Clinac; Calculo De factor cuna efectiva para cuna dinamica mejorada de un Clinac 2100CD de Varian

    Energy Technology Data Exchange (ETDEWEB)

    Pizarro Trigo, F.; Morillas Ruiz, J.; Nunuz Martinez, L.; Sanchez Jimenez, J.

    2011-07-01

    The purpose of this paper is to compare different methods of calculating the effective factor enhanced dynamic wedge (EDWF) with the values ??obtained in measurements of symmetric and asymmetric fields.

  7. On the Effect of Structural Response on the Hydrodynamic Loading of a Free-Falling Wedge

    Science.gov (United States)

    Ikeda, Christine; Taravella, Brandon; Judge, Carolyn

    2016-11-01

    High-speed planing craft are subjected to repeated slamming events in waves that can be very extreme depending on the wave topography, impact angle of the ship, forward speed of the ship, encounter angle, and height out of the water. The current work examines this fluid-structure interaction problem through the use of wedge drop experiments and a theoretical prediction. The experimental program consisted of two 20° deadrise angle wedges dropped from a range of heights, 0 . 15 theory in order to determine the effects of flexibility on the hydrodynamic pressure. The code assumes a rigid structure, therefore, the results between the code and the first experiment are in good agreement. The second experiment shows pressure magnitudes that are lower than the predictions due to the energy required to deform the structure. This work is funded by the Office of Naval Research and the state of Louisiana Board of Regents Industrial Ties and Reseach Subprogram.

  8. Generation of vector beams using a double-wedge depolarizer: Non-quantum entanglement

    Science.gov (United States)

    Samlan, C. T.; Viswanathan, Nirmal K.

    2016-07-01

    Propagation of horizontally polarized Gaussian beam through a double-wedge depolarizer generates vector beams with spatially varying state of polarization. Jones calculus is used to show that such beams are maximally nonseparable on the basis of even (Gaussian)-odd (Hermite-Gaussian) mode parity and horizontal-vertical polarization state. The maximum nonseparability in the two degrees of freedom of the vector beam at the double wedge depolarizer output is verified experimentally using a modified Sagnac interferometer and linear analyser projected interferograms to measure the concurrence 0.94±0.002 and violation of Clauser-Horne-Shimony-Holt form of Bell-like inequality 2.704±0.024. The investigation is carried out in the context of the use of vector beams for metrological applications.

  9. Physical Analysis of Cross-Wedge Rolling Process of a Stepped Shaft

    Directory of Open Access Journals (Sweden)

    Łukasz Wójcik

    2017-12-01

    Full Text Available The paper presents experimental- model research results on the process of cross-wedge rolling of an axially-symmetrical element (stepped shaft. During research was used plastic mass on the basis of waxes in black and white colour. The aim of this experimental research was to determine the best option of forming in terms of values obtained and the course of forces. Physical examination was carried out using specialist machines, that is model and laboratory cross-wedge rolling mill. Experimental analysis was carried out using billets with the temperature of 15°C, whereas the actual process was carried out for billet from C45 carbon steel of temperature 1150°C. The study compared the dimensions of the components obtained during rolling tests and forming forces obtained in the result of physical modeling with forces obtained during real tests.

  10. Experimental constraints on the impact of slab dip, gaps and rollback on mantle wedge flow

    Science.gov (United States)

    MacDougall, J. G.; Szwaja, S.; Kincaid, C. R.; Fischer, K. M.

    2012-12-01

    We conducted fluids experiments to better understand how subduction zone mantle flow and seismic anisotropy relate to slab dip variations, slab gaps, and retrograde trench motion. Subducting lithosphere was modeled with two rubber-reinforced continuous belts that pass around rollers at the trench and at the equivalent of 670 km depth; the advecting mantle was represented by an isoviscous glucose fluid. Each belt had a variable dip and speed, and trench rollback was modeled using translation of the belt system. Neutral density rotation markers ("whiskers") as well as beads and bubbles were used to track flow patterns; whiskers were also used as proxies for finite strain and were assumed to reflect the evolution of olivine fabrics and anisotropy. The dips of the two slab segments were systematically varied from 30° to 80° at subduction rates equivalent to 4 and 8 cm/yr, and in select cases trench rollback equivalent to 3 cm/yr was imposed. Reference cases with identical parameters for the two slab belts produced mantle wedge flow that reflected simple entrainment by the slab, with flow lines that were roughly trench-normal in much of the wedge, except for toroidal flow around the lateral edges of the slab. Dip variations between the slab segments deflected mantle wedge flow lines towards trench-parallel in the direction of the shallower slab, in agreement with prior numerical modeling studies. The degree of along-arc deflection increased as the slab dip difference grew. Deflection also increased as the absolute dip of the shallower-dipping segment decreased, as predicted by analytical estimates of trench-parallel pressure gradients (Hall et al., 2000). Whisker alignments showed the greatest evidence for extension and alignment of olivine a-axes that are sub-parallel to the trench in the mantle wedge close to the change in slab dip, consistent with the numerical models of Kneller and Van Keken (2007). The addition of trench rollback to a given set of experimental

  11. Effects of radiation on convection heat transfer of Cu-water nanofluid past a moving wedge

    Directory of Open Access Journals (Sweden)

    Salama Faiza A.

    2016-01-01

    Full Text Available Heat transfer characteristics of a two-dimensional steady hydrodynamic flow of water-based copper(Cu nanofluid over a moving wedge, taking into account the effects of thermal radiation, have been investigated numerically. The Rosseland approximation is used to describe the radiative heat flux in the energy equation. The governing fundamental equations are first transformed into a system of ordinary differential equations and solved numerically by using the fourth-order Runge-kutta method with shooting technique. A comparison with previously published work has been carried out and the results are found to be in good agreement. The existence of unique and dual solutions for self-similar equations of the flow and heat transfer are analyzed numerically. The results indicate that there is strong dependence of the thermal gradient at the surface of the wedge on both velocity ratio parameter and thermal radiation.

  12. Refinement of the wedge bar technique for compression tests at intermediate strain rates

    Directory of Open Access Journals (Sweden)

    Stander M.

    2012-08-01

    Full Text Available A refined development of the wedge-bar technique [1] for compression tests at intermediate strain rates is presented. The concept uses a wedge mechanism to compress small cylindrical specimens at strain rates in the order of 10s−1 to strains of up to 0.3. Co-linear elastic impact principles are used to accelerate the actuation mechanism from rest to test speed in under 300μs while maintaining near uniform strain rates for up to 30 ms, i.e. the transient phase of the test is less than 1% of the total test duration. In particular, a new load frame, load cell and sliding anvil designs are presented and shown to significantly reduce the noise generated during testing. Typical dynamic test results for a selection of metals and polymers are reported and compared with quasistatic and split Hopkinson pressure bar results.

  13. Uniform physical theory of diffraction equivalent edge currents for truncated wedge strips

    DEFF Research Database (Denmark)

    Johansen, Peter Meincke

    1996-01-01

    New uniform closed-form expressions for physical theory of diffraction equivalent edge currents are derived for truncated incremental wedge strips. In contrast to previously reported expressions, the new expressions are well behaved for all directions of incidence and observation and take a finite...... value for zero strip length. This means that the expressions are well suited for implementation in general computer codes. The new expressions are expressed as the difference between two terms. The first term is obtained by integrating the exact fringe wave current on a wedge along an untruncated...... incremental strip extending from the leading edge of the structure under consideration. The second term is calculated from an integration of the asymptotic fringe wave (FW) current along another untruncated incremental strip extending from the trailing edge of the structure. The new expressions are tested...

  14. Switched reluctance motor with magnetic slot wedges for automotive traction application

    Science.gov (United States)

    Belhadi, M.'Hamed; Krebs, Guillaume; Marchand, Claude; Hannoun, Hala; Mininger, Xavier

    2015-12-01

    The switched reluctance motor (SRM) is very attractive because of its many advantages especially in electric vehicle (EV). However, it presents two major drawbacks: torque ripples and stator vibrations. These phenomena are the cause of a disturbing noise. In order to reduce the torque ripples and the radial force (main cause of the stator vibrations), one solution is to add magnetic slot wedges. In this paper, a SRM with wedges is compared to the conventional one including some static and dynamic features. First, field lines, magnetization curves and static torques are discussed. Secondly, torque-speed curves, harmonic analyzes and cartographies with minimum ripples are compared. The last includes several operating points (speed-torque) in steady state.

  15. Dabigatran versus warfarin in the treatment of acute venous thromboembolism

    NARCIS (Netherlands)

    Schulman, Sam; Kearon, Clive; Kakkar, Ajay K.; Mismetti, Patrick; Schellong, Sebastian; Eriksson, Henry; Baanstra, David; Schnee, Janet; Goldhaber, Samuel Z.; Schulman, S.; Eriksson, H.; Goldhaber, S.; Kakkar, A.; Kearon, C.; Mismetti, P.; Schellong, S.; Minar, E.; Bergqvist, D.; Tijssen, J.; Prins, M. [=Martin H.; Büller, H.; Otten, J.; Peters, R.; Mac Gillavry, M.; Pol, S.; Burroughs, A.; Gilmore, I.; Bluguermann, J.; Carlevaro, O.; Dipaola, L.; Gitelman, P.; Santos, D.; Schygiel, P.; Baker, R.; Blombery, P.; Gallus, A.; Gan, E.; Gibbs, H.; Salem, H.; Baghestanian, M.; Pilger, E.; Sturm, W.; Debing, E.; Gadisseur, A.; Hainaut, P.; Verhamme, P.; Wautrecht, J.-C.; Zicot, M.; Bizzachi, J. M. Annichino; Araujo, G.; de Araujo, J. Dalmo; Panico, F. M. Duarte Brandão; Nagato, Y.; Pereira, A. H.; Leao, P. Puech; Ramaciotti, E.; Moreira, R. C. Rocha; Timi, J.; Anderson, D.; Crowther, M.; Dolan, S.; Eikelboom, J.; Spencer, F.; Game, M.; Kahn, S.; Kassis, J.; Klinke, P.; Kovacs, M.; Milot, A.; Ritchie, B.; Rodger, M.; Solymoss, S.; Villeneuve, J.; Yeo, E.; Cervinka, P.; Homza, M.; Hrdy, P.; Klimsa, Z.; Lang, P.; Maly, R.; Oral, I.; Reichert, P.; Spinar, J.; Varejka, P.; Vladimir, J.; Brønnum-Schou, J.; Jensen, S.; Jensen, S. E.; Kristensen, K. S.; Nielsen, H.; Wiemann, O.; Bost, V.; Buchmuller, A.; Guillot, K.; Laurent, P.; Lecomte, F.; Mottier, D.; Quere, I.; Wahl, D.; Beyer, J.; Dormann, A.; Hoffmann, U.; Maier, M.; Mietaschk, A.; Katsenis, K.; Klonaris, C.; Liappis, C.; Acsady, G.; Berhes, I.; Boda, Z.; Farkas, K.; Jakucs, J.; Kollar, L.; Matyas, L.; Riba, M.; Sereg, M.; Aggarwal, R.; Banker, D.; Bharani, A.; Gadkari, M.; Hiremath, J.; Jain, A.; Kareem, S.; Lyengar, S.; Parakh, R.; Sekar, N.; Srinivas, A.; Suresh, K.; Vujay, T.; Brenner, B.; Efrati, S.; Elias, M.; Gavish, D.; Grossman, E.; Lahav, M.; Lishner, M.; Zeltser, D.; Agnelli, G.; Cimminiello, C.; Palareti, G.; Prandoni, P.; Santonastaso, M.; Silingardi, M.; Lee, E. Aldrett; Andrade, J. M. Fontes; Valles, J. Jaurrieta; Biesma, D.; Dees, A.; Fijnheer, R.; Hamulyak, K.; Kramer, M. H. H.; Leebeek, F. W. G.; Lieverse, L.; Nurmohamed, M. T.; Chunilal, S.; Jackson, S.; Ockelford, P.; Smith, M.; Njaastad, A. M.; Sandseth, P. M.; Tveit, A.; Waage, A.; Barata, J.; Capitao, M.; Fernandes, F. E.; Leitão, A.; Providência, L.; Alohin, D. I.; Belentsov, S.; Chernyatina, M.; Chernyavsky, A.; Fokin, A.; Gubenko, A.; Guz, V. Alexander V.; Katelnitsky, I.; Khamitov, A. A. A.; Khitaryan, A.; Khubulava, G.; Mikhailov, I.; Shkurin, V.; Staroverov, I.; Tchumakov, A.; Zaporozhsky, A.; Duris, T.; Poliacik, P.; Spisak, V.; Szentivanyi, M.; Zubek, V.; Adler, D.; Kelbe, D.; Le Roux, D.; Pieterse, A.; Routier, R.; Siebert, R.; Sloane, B.; Smith, C.; van Rensburg, H.; del Toro, J.; García-Fuster, M. J.; Mateo, J.; Monreal, M.; Nieto, J. A.; Sánchez-Molini, P.; Sedano, C.; Trujillo, J.; Valle, R.; Villalta, J.; Aagesen, J.; Carlsson, A.; Johansson, L.; Lärfars, G.; Lindmarker, P.; Säfvenberg, U.; Själander, A.; Bengisun, U.; Calkavur, T.; Guney, M. R.; Karahan, S.; Kurtoglu, M.; Sakinci, U.; Gubka, A.; Mishalov, V.; Skupyy, O.; Cohen, A.; Keeling, D.; Kesteven, P.; MacCallum, P.; Maclean, R.; Shah, P.; Watson, H.; Bartkowiak, A.; Bolster, E.; Botnick, W. C.; Burnett, B.; Chervu, A.; Comerota, A. J.; Dy, N. M.; Fulco, F. A.; Gossage, J. R.; Kaatz, S.; Lahiri, B.; Lerner, R. G.; Masson, J. A.; Moll, S.; Morganroth, M.; Patel, K.; Paulson, R.; Powell, R.; Samson, R.; Seibert, A.; Spyropoulos, A.; Vrooman, P. S.

    2009-01-01

    BACKGROUND: The direct oral thrombin inhibitor dabigatran has a predictable anticoagulant effect and may be an alternative therapy to warfarin for patients who have acute venous thromboembolism. METHODS: In a randomized, double-blind, noninferiority trial involving patients with acute venous

  16. Central venous oxygen saturation during hypovolaemic shock in humans

    DEFF Research Database (Denmark)

    Madsen, P; Iversen, H; Secher, N H

    1993-01-01

    We compared central venous oxygen saturation and central venous pressure (CVP) as indices of the effective blood volume during 50 degrees head-up tilt (anti-Trendelenburg's position) induced hypovolaemic shock in eight healthy subjects. Head-up tilt increased thoracic electrical impedance from 31...

  17. Awareness of Venous thromboembolism among doctors in a ...

    African Journals Online (AJOL)

    Background: Venous thromboembolic (VTE) is a preventable leading cause of morbidity and mortality worldwide and is a cause of sudden death. Awareness of VTE among doctors will reduce the incidence of unexpected deaths in hospitalised patients. Objective: To assess doctors' awareness of venous thromboembolism ...

  18. Can Peripheral Central Venous Lines be inserted safely and ...

    African Journals Online (AJOL)

    Background: Primary care settings often lack facilities for radiological evaluation of the position of supra-and infra-clavicularly inserted central venous catheters. If peripherally inserted central venous lines could reliably be successfully inserted this would make the need for immediate confirmatory radiological studies less ...

  19. What went wrong? The flawed concept of cerebrospinal venous insufficiency

    NARCIS (Netherlands)

    Valdueza, J.M.; Doepp, F.; Schreiber, S.J.; van Oosten, B.W.; Schmierer, K.; Paul, F.; Wattjes, M.P.

    2013-01-01

    In 2006, Zamboni reintroduced the concept that chronic impaired venous outflow of the central nervous system is associated with multiple sclerosis (MS), coining the term of chronic cerebrospinal venous insufficiency ('CCSVI'). The diagnosis of 'CCSVI' is based on sonographic criteria, which he found

  20. Rivaroxaban or Aspirin for Extended Treatment of Venous Thromboembolism

    NARCIS (Netherlands)

    Weitz, Jeffrey I.; Lensing, Anthonie W. A.; Prins, Martin H.; Bauersachs, Rupert; Beyer-Westendorf, Jan; Bounameaux, Henri; Brighton, Timothy A.; Cohen, Alexander T.; Davidson, Bruce L.; Decousus, Hervé; Freitas, Maria C. S.; Holberg, Gerlind; Kakkar, Ajay K.; Haskell, Lloyd; van Bellen, Bonno; Pap, Akos F.; Berkowitz, Scott D.; Verhamme, Peter; Wells, Philip S.; Prandoni, Paolo; Bianchi, Alessandra; Brighton, Tim; Carroll, Patrick; Chong, Beng; Chunilal, Sanjeev; Coughlin, Paul; Curnow, Jennifer; Jackson, David; Tran, Huyen; Ward, Chris; Brodmann, Marianne; Kyrle, Paul; Marschang, Peter; Petkov, Ventzislav; Hainaut, Philippe; Jordens, Paul; Vandekerkhof, Jos; Wautrecht, Jean-Claude; Annichino-Bizzacchi, Joyce; Correa, Joao; Cukier, Alberto; Freire, Antonio; Pereira, Adamastor; Porto, Carmen; Sacilotto, Roberto; Vasconcelos Costa, Agenor; Della Siega, Anthony; Dolan, Sean; Le Gal, Gré goire; Gross, Peter; Kahn, Susan; Kassis, Jeannine; Kovacs, Michael; Pesant, Yves; Ritchie, Bruce; Schulman, Sam; Shivakumar, Sudeep; Solymoss, Susan; Chang, Shu; Chen, Rongchang; Chen, Zhong; Chen, Hong; Dai, Xiangchen; Fang, Baoming; Fu, Weiguo; Gao, Xinglin; Huang, Jinhua; Lai, Yanping; Li, Li; Li, Xiaoqiang; Li, Yiqing; Liu, Jinming; Liu, Shuang; Ma, Wenjiang; Ni, Songshi; Qin, Zhiqiang; Shi, Guochao; Tian, Hongyan; Wang, Shenming; Wang, Lie; Xiao, Wei; Ying, Kejing; Yu, Guanfeng; Yuan, Yadong; Zhang, Jie; Zhang, Jin; Zhang, Xinri; Zhang, Liyan; Zhu, Lei; Chlumský , Jaromir; Chochola, Jiri; Dunaj, Milna; Kovarova, Katerina; Lang, Pavel; Matoš ka, Petr; Podpera, Ivo; Spacek, Rudolf; Stehlikova, Olga; Brø nnum-Schou, Jens; Egstrup, Kenneth; Gislason, Gunnar; Jeppesen, Jorgen; May, Ole; Nielsen, Henrik; Wiggers, Henrik; Achkar, Antoine; Aquilanti, Sandro; Benhamou, Ygal; Brisot, Dominique; Bura-Riviere, Alessandra; Castella, Nadine; Elias, Antoine; Falvo, Nicolas; Ferrari, Emile; Lacroix, Philippe; Mahe, Isabelle; Meneveau, Nicolas; Messas, Emmanuel; Mismetti, Patrick; Montaclair, Karine; Mottier, Dominique; Moumneh, Thomas; Paleiron, Nicolas; Parent, Florence; Pernod, Gilles; Sanchez, Olivier; Schmidt, Jeannot; Simoneau, Guy; Stephan, Dominique; Amann, Berthold; Blessing, Erwin; Czihal, Michael; Espinola-Klein, Christine; Kahrmann, Gerd; Licka, Manuela; Neumeister, Axel; Schellong, Sebastian; Boda, Zoltan; Farkas, Katalin; Gurzo, Mihaly; Katona, Andras; Riba, Maria; Sipos, Gyula; Tó th, Kalman; Braester, Andrei; Elias, Mazen; Gafter-Gvili, Anat; Gavish, Dov; Hussein, Osamah; Lishner, Michael; Schiff, Elad; Spectre, Galia; Tzoran-Rozenthal, Inna; Zimlichman, Reuven; Ageno, Walter; Agnelli, Giancarlo; Bova, Carlo; Garbelotto, Raffaella; Ghirarduzzi, Angelo; Imberti, Davide; Pesavento, Raffaele; Porreca, Ettore; Visonà , Adriana; Flota Cervera, Luis; Llamas Esperó n, Guillermo; Rodriguez-Gonzalez, Daniel; Solis Morales, Lucas; Boersma, Willem; ten Cate, Hugo; Erdkamp, Franciscus; Grifioen-Keijzer, Anita; Marwijk Kooy, Marinus; Meijer, Karina; Middeldorp, Saskia; Swart-Heikens, Janneke; ten Wolde, Marije; Westerweel, Peter; Braithwaite, Irene; Harper, Paul; Merriman, Eileen; Ockelford, Paul; Royle, Gordon; Smith, Mark; Ghanima, Waleed; Sandset, Per Morten; Abola, Maria; Chę ciń ski, Pawel; Grzelakowski, Pawel; Lewczuk, Jerzy; Sobkowicz, Bozena; Tomkowski, Witold; Abramov, Igor; Chechulov, Pavel; Karpenko, Andrey; Katelnitskiy, Ivan; Kazakov, Andrey; Makarova, Olga; Panchenko, Elizaveta; Sergeeva, Elena; Subbotin, Yuriy; Suchkov, Igor; Zeltser, Mikhail; Adler, David; Breedt, Johannes; Fourie, Nyda; Isaacs, Rashid; Jacobson, Barry; Siebert, Heidi; van Zyl, Louis; Choi, Jung-Hyun; Kang, Seok-Min; Kim, Kye-Hun; Kim, Hyo-Soo; Kim, Dong-Ik; Min, Seung-Kee; Park, Ki Hyuk; Garcí a-Bragado Dalmau, Fernando; Gó mez Cerezo, Jorge; Mirete, Jose Carlos Ferrer; Riera, Antonio; del Toro, Jorge; Eriksson, Henry; Torstensson, Ingemar; Banyai, Martin; Baumgartner, Iris; Mazzolai, Lucia; Periard, Daniel; Righini, Marc; Staub, Daniel; Chiang, Chern-En; Chiu, Kuan-Ming; Pai, Pei-Ying; Angchaisuksiri, Pantep; Chansung, Kanchana; Ö ngen, Gul; Tuncay, Esin; Alikhan, Raza; Chetter, Ian; Kesteven, Patrick; Nokes, Tim; Bauer, Kenneth; Comerota, Anthony; Elias, Darlene; Garcia, David; Gibson, Kathleen; Ginsberg, Daniel; Jenkins, Jeffrey; Kingsley, Edwin; Lambert, Richard; Lyons, Roger; Pullman, John; Shah, Vinay; Smith, S. Wayne; Stein, Robert; Tapson, Victor; Walsh, John; Wang, Tzu-Fei; Do Loi, Doan; Do Quang, Huan; Pham, Nguyen

    2017-01-01

    BACKGROUND Although many patients with venous thromboembolism require extended treatment, it is uncertain whether it is better to use full- or lower-intensity anticoagulation therapy or aspirin. METHODS In this randomized, double-blind, phase 3 study, we assigned 3396 patients with venous

  1. Patterns of superficial venous arrangement in the cubital fossa of ...

    African Journals Online (AJOL)

    Background: The cubital fossa is a common site for the removal of venous blood for analysis, transfusion, and intravenous therapy. The superficial venous return from the upper limb follows two or three major superficial veins, which are extremely variable; these include the cephalic, basilic, median cubital, and antebrachial ...

  2. Central venous catheters and catheter locks in children with cancer

    DEFF Research Database (Denmark)

    Handrup, Mette Møller; Møller, Jens Kjølseth; Schrøder, Henrik

    2013-01-01

    To determine if the catheter lock taurolidine can reduce the number of catheter-related bloodstream infections (CRBSI) in pediatric cancer patients with tunneled central venous catheters (CVC).......To determine if the catheter lock taurolidine can reduce the number of catheter-related bloodstream infections (CRBSI) in pediatric cancer patients with tunneled central venous catheters (CVC)....

  3. Positive outcome of medical leeches (hirudotherapy) for venous ...

    African Journals Online (AJOL)

    been treated for several years for chronic superficial venous insufficiency with compression therapy (stockings) and micronized diosmin orally. She had no past or present trophic ulcers, just slight bilateral edema. A routine blood test was within normal limits. Echo Doppler evaluation confirmed chronic venous disease (CVD) ...

  4. Thrombin Avtivable Fibrinolysis Inhibitor in Venous and Arterial Thrombosis

    NARCIS (Netherlands)

    E.L.E. de Bruijne

    2011-01-01

    textabstractVenous and arterial thromboses are major causes of morbidity and mortality. Venous thrombosis is the result of pathological occlusive clot formation in the veins. It occurs mainly in the deep veins of the leg (deep vein thrombosis), from which parts of the clot frequently embolize to the

  5. Sonography and risk factors for lower limb deep venous thrombosis ...

    African Journals Online (AJOL)

    Background: Lower limb deep venous thrombosis (DVT), and its sequelae (lower limb chronic venous insufficiency and pulmonary embolism) are now well acknowledged as major haematological problems in the world, for which appropriate and accurate means of diagnosis is necessary. Developments in ultrasound have ...

  6. Edoxaban versus Warfarin for the Treatment of Symptomatic Venous Thromboembolism

    NARCIS (Netherlands)

    Büller, Harry R.; Décousus, Hervé; Grosso, Michael A.; Mercuri, Michele; Middeldorp, Saskia; Prins, Martin H.; Raskob, Gary E.; Schellong, Sebastian M.; Schwocho, Lee; Segers, Annelise; Shi, Minggao; Verhamme, Peter; Wells, Phil; Agnelli, Giancarlo; Angchaisuksiri, Pantep; Banyai, Martin; Bauersachs, Rupert; van Bellen, Bonno; Blüguermann, Julio; Boda, Zoltán; Bounameaux, Henri; Brenner, Benjamin; Brighton, Tim; Castañon, Javier Diaz; Chechulov, Pavel; Chlumský, Yaromir; Cohen, Alexander; Davidson, Bruce; Decousus, Hervé; Eriksson, Henry; Gallus, Alexander; Gudz, Ivan; Jacobson, Barry; Heng, Lee Lai; Lyons, Roger; Meijer, Karina; Minar, Erich; Monreal, Manuel; Nakamura, Mashio; Oh, Doyeun; Öngen, Gül; Parakh, Rajiv; Piovella, Franco; Raskob, Gary; Rehm, Jeffery; Sandset, Per Morten; Schellong, Sebastian; Smith, Mark; Sokurenko, German; Tomkowski, Witold; Torp-Pedersen, Christian; Wang, Chen; Wang, Yuqi; Weitz, Jeff; Yanushko, Vyacheslav; Yin, Wei-Hsian; Prins, Martin; Beenen, Ludo; Brandjes, Dees; MacGillavry, Melvin; Kaplowitz, Neil; Otten, Hans-Martin; Pessayre, Dominique; Peters, Ron; Roos, Yvo; Slagboom, Ton; Eikelboom, John; Crowther, Mark; Roberts, Robin; Vanassche, Thomas; Vandenbriele, Christophe; Debaveye, Barbara; Dani, Viddhi; van Bergen, Petro; Gerrits, Paul; van Kranen, Robbert; Lanz, Hans; Grosso, Michael; Kappelhoff, John; Franc, John; Zhang, George; Lin, Min; Crerand, William; Giordano, Chris; Skinner, Maureen; Hurley, Steve; Lovelace, Gregg; Barrier, Robert; Betcher, Josh; Alvarez, C.; Amuchastegui, L. M.; Blüguermann, J.; Cassettari, A.; Ceressetto, J.; Hrabar, NN; Macin, S.; Mahuad, C.; Oberti, P.; Santini, F.; Baker, R. I.; Blombery, P.; Brighton, T.; Carroll, P.; Chong, B.; Coughlin, P.; Crispin, P.; Fletcher, J.; Gallus, A.; Serisier, D. J.; Tran, H.; Chan, N.; Stafford, L.; Ward, C.; Baghestanian, M.; Kyrle, P. A.; Eischer, L.; Traby, L.; Marschang, P.; Mathies, R.; Pilger, E.; Brodmann, M.; Roithinger, F.; Weltermann, A.; Adzerikho, I.; Davidovskaya, E.; Gorokhovsky, S.; Maslianski, B.; Kulik, A.; Yanushka, A.; de Vleeschauwer, P.; Debing, E.; Duchateau, J.; Gustin, M.; Hainaut, P.; Vandekerkhof, J.; Verhamme, P.; Peerlinck, K.; Verstraeten, P.; Wautrecht, J. C.; Motte, S.; Annichino-Bizzacchi, J. M.; Mello, T. B. T.; Menezes, F. H.; Burihan, M.; Cavalcanti, M.; Correa, J.; Correa de Carvalho, F.; Cukier, A.; Manenti, E.; Manenti, E. R.; Sacilotto, R.; Timi, J. M.; van Bellen, B.; Kahn, S. R.; Kovacs, M.; Langner, A. Lazo; VanSpronsen, H.; Ritchie, B.; Shafai-Sarshar, R.; Shivakumar, S.; Anderson, D.; Robinson, K.; Gallant, B.; Wells, P.; Karovitch, A.; Scarvelis, D.; Carrier, M.; Bai, C. X.; Chen, R. C.; Cheng, Z. Z.; Du, Y. C.; Hu, X. Y.; Gu, Y. Q.; Hao, Q. L.; Sun, S. B.; Wang, C.; Jiang, L.; Liu, C. J.; Liu, C. W.; Liu, S.; Wang, X. X.; Ye, X. F.; Ma, Z.; Qin, Z. Q.; Qin, X. J.; Tian, H. Y.; Wang, Y. Q.; Shi, Z. Y.; Wen, F. Q.; Wu, Q.; Yang, Y. H.; Kuang, T. G.; Yang, H.; Ying, K. J.; Ma, G. F.; Yuan, Y. D.; Yu, J.; Gong, X. W.; Zhang, F. X.; Zhang, J.; Zhang, S. X.; Zhang, J. W.; Zhang, L.; Zhao, J. C.; Huang, B.; Zhao, J.; Chlumsky, J.; Hola, D.; Hirmerova, J.; Hutyra, M.; Klimsa, Z.; Holub, M.; Kovarova, K.; Lang, P.; Ryba, M.; Podoubský, R.; Matoska, P.; Mayer, O.; Patek, F.; Tupa, M.; Spacek, R.; Urbanova, R.; Blazejova, S.; Vitovec, M.; Andersen, B.; Brønnum-Schou, J.; Dominguez, H.; Egstrup, K.; Auscher, S.; Jeppesen, J.; Asferg, C.; Vishram, J.; Nielsen, H.; Galsgaard, I.; Michaelsen, M.; Haugaard-Nielsen, B.; Ostergaard, O.; Poulsen, S. H.; Torp-Pedersen, C.; Masik, S.; Kadarik, M.; Meriste, S.; Paumets, M.; Laheäär, M.; Raidjuk, L.; Accassat, S.; Buchmuller, A.; Mismetti, P.; Achkar, A.; Aquilanti, S.; Rifaï, A.; Breuil, N.; Schmidt, J.; Brisot, D.; Brousse, C.; de la Fuentes, P. Tarodo; Chakra, M.; Crestani, B.; Desormais, I.; Lacroix, P.; Diamand, J. M.; El Kouri, D.; Clairand, R.; Elias, A.; Ferrari, E.; Doyen, D.; Chiche, O.; Grange, C.; Guenneguez, H.; Lacut, K.; Couturaud, F.; Mottier, D.; Leroux, L.; Lorcerie, B.; de Maistre, E.; Berthier, S.; Mahe, I.; Martin, M.; Meneveau, N.; Meyer, G.; Sanchez, O.; Montaclair, K.; Pavic, M.; Pernod, G.; Imbert, B.; Quere, I.; Galanaud, J. P.; Roy, P. M.; Sevestre, M. A.; Simoneau, G.; Stephan, D.; Aleil, B.; Mirea, C.; Trinh-Duc, A.; von Bilderling, P. Baron; Beyer-Westendorf, J.; Werth, S.; Köhler, C.; Halbritter, K.; Diehm, C.; Espinola-Klein, C.; Weisser, G.; Franke, D.; Heuer, H.; Horacek, T.; Kahrmann, G.; Kroening, R.; Lawall, H.; Roecken, M.; Schellong, S. M.; Pomper, L.; Voigts, B.; Bernhard, S.; Frommhold, R.; Stellbrink, C.; Boda, Z.; Ilonczai, P.; Olah, Z.; Razso, K.; Schlammadinger, A.; Farkas, K.; Kolossváry, E.; Szabó, I.; Frankfurter, Z.; Gasztonyi, B.; Gurzó, M.; Klucsik, Z.; Kovacs, A.; Szigeti, S.; Varga, C.; Landi, A.; Nyirati, G.; Pecsvarady, Zs; Riba, M.; Sámson, Z.; Sipos, Gy; Szigyártó, M.; Sebő, N.; Szabó, T. Janossikné; Toth, K.; Agarwal, S.; Arneja, J.; Babhulkar, S.; Balaji, R.; Banker, D.; Bhagavan, N. K.; Bhonagiri, S.; Mehta, A.; Dayasagar Rao, V.; Desai, P.; Desai, S. C.; Chandrashekar, A. R.; Singh, R.; Deshpande, A.; Dharmadhikari, A.; Durairaj, N.; Ghaisas, N.; Gupta, S.; Jain, R.; Jindal, R.; Kamerkar, D.; Kothiwale, V. A.; Kothurkar, A.; Kulkarni, R.; Kumar, S.; Mody, B.; Nagabhushan, K. N.; Pandharpurkar, H. K.; Joshi, S.; Parakh, R.; Grover, T.; Patel, J.; Patel, K.; Dudhagra, N.; Pawar, N.; Penurkar, M.; Pinjala, R.; Rai, K.; Rao, B.; Raval, M.; Raval, A.; Mehta, P.; Ravi Kishore, A. G.; Saravanan, S.; Shetty, P.; Srinivas, A.; Suresh, K. R.; Sumanthraj, K.; Girija, K. R.; Vinod, M. Vijan; Gavish, D.; Ashkenazy, B.; Braester, A.; Caraco, Y.; Elias, M.; Goldstein, L.; Grossman, E.; Lahav, M.; Lishner, M.; Lugassy, G.; Oliven, A.; Rachmilevitz, R.; Tzoran, I.; Brenner, B.; Yeganeh, S.; Zeltser, D.; Zimlichman, R.; Ageno, W.; Barillari, G.; Pasca, S.; Bortoluzzi, C.; Cattaneo, M.; Falanga, A.; Ghirarduzzi, A.; Lodigiani, C.; Picchi, C.; Iosub, D. I.; Porreca, E.; Prandoni, P.; Quintavalla, R.; Siragusa, S.; Akita, T.; Aoyama, T.; Fujimoto, K.; Hanzawa, K.; Ikeda, U.; Iwata, H.; Kobayashi, T.; Kondo, K.; Kurimoto, T.; Maeda, H.; Mo, M.; Munemasa, M.; Murakami, H.; Nishi, Y.; Nishibe, T.; Nishigami, K.; Nunohiro, T.; Obayashi, T.; Satoh, T.; Satokawa, H.; Shimizu, K.; Shiroma, H.; Sonoda, M.; Suzuki, Y.; Taniguchi, S.; Tsujita, K.; Yamada, N.; Yasuda, C.; Yoshida, H.; Chang, H. J.; Choi, W. I.; Kwon, K. Y.; Rho, B. H.; Choi, J. S.; Hong, Y. S.; Joh, J. H.; Kim, D. J.; Kim, H. S.; Kim, S. H.; Kim, Y. K.; Kim, K. U.; Kim, J. Y.; Kwon, T. W.; Lee, T. S.; Lim, S. Y.; Mun, Y. C.; Oh, D. Y.; Park, K. H.; Yun, W. S.; Yoon, H. I.; Diaz-Castañon, J.; Flota, L. F.; Galindo, J.; Gomez Lara, J.; Jerjes-Sanchez, C.; Palomar-Lever, A.; Rodriguez, D.; Higareda, I.; Boersma, W. G.; de Graaff, C. S.; Oudeman, L.; Brans, E.; Bredie, S. J. H.; Dees, A.; Erdkamp, F.; Peters, F.; Fijnheer, R.; Gerdes, V. E. A.; Griffioen, A.; Jie, K.-S. G.; Meijer, K.; Kooistra, H.; Wiewel-Verschueren, S.; Kamphuisen, P. W.; van Es, J.; Eerenberg, E. S.; Swart Heikens, J.; ten Cate, H.; ten Wolde, M.; Hes, R.; Atalay, S.; Harper, P.; Merriman, E.; Ockelford, P.; Hulton, M. H.; Phillips, J.; Royle, G.; Ford, A.; Smith, M.; Ghanima, W.; Amundsen, H.; Sandset, P. M.; Abola, M. T.; Ganzon, M. S.; Germar, A.; Checinski, P.; Kwasniewski, A.; Tomkowski, W.; Zechowicz, T.; Apartsin, K.; Arutyunov, G.; Barbarash, O.; Burov, Y.; Chechulov, P.; Varaksina, E.; Chernyatina, M.; Gladchenko, M.; Belikov, L.; Fokin, A.; Gubenko, A.; Igor, K.; Olga, M.; Kazakov, Y.; Kazakov, A.; Krasavin, V.; Linev, K.; Plechev, V.; Shesternya, P.; Shkurin, V.; Shvalb, P.; Sokurenko, G.; Sonkin, I.; Remizov, A.; Chernykh, K.; Staroverov, I.; Subbotin, Y.; Zeltser, M.; Seletsky, A.; Iliynykh, A.; Zilber, A.; Zubareva, N.; Tkachenko, I.; Pakhomova, A.; Raghuram, J.; Ng, H. J.; Sin, K.; Adler, D.; Weber, F.; van der Jagt, R.; Basson, M.; Becker, J.; Ellis, G.; Isaacs, R.; Jacobson, B.; Louw, S.; van Rensburg, Jansen; Siebert, H.; Skosana, F.; van Marle, J.; van Zyl, L.; le Roux, R.; Williams, P.; Cereto, F.; Garcia-Bragado, F.; Miranda, R. Tirado; Carlsson, A.; Eriksson, H.; Villegas-Scivetti, M.; Ottosson, E.; Sjalander, A.; Torstensson, I.; Banyai, M.; Afarideh, R.; Gallino, A.; Mazzolai, L.; Righini, M.; Staub, D.; Chen, C. J.; Chiang, C. E.; Wang, K. L.; Chiu, K. M.; Huang, J. H.; Lai, W. T.; Pai, P. Y.; Lin, K. H.; Wang, J. H.; Wu, C. C.; Yin, W. H.; Huang, C. L.; Angchaisuksiri, P.; Kulpraneet, M.; Rojnuckarin, P.; Öngen, G.; Duman, B.; Ozkan, S.; Savas, I.; Selçuk, T.; Tuncay, E.; Gerasymov, V.; Gubka, O.; Gudz, I.; Voloshyn, M.; Nikulnikov, P.; Danylets, A.; Prasol, V.; Rusyn, V.; Sergeev, O.; Shtutin, O.; Skupyy, O.; Tatarin, A.; Venger, I.; Cohen, A. T.; Patel, R.; Hunt, B. J.; Kesteven, P.; Robson, L.; MacCallum, P.; Nokes, T.; Rose, P.; Acs, P.; Gordan, L.; Bhatia, A.; Ali, M.; Amin, D.; Masson, J.; Gavi, E.; Ayele, E.; Ayeni, O.; Canosa, R.; Chavous, D.; Chen, D.; Comerota, A.; Concha, M.; Cunanan-Bush, M.; Daboul, N.; Daggubati, S.; Dang, N.; DiBella, N.; Driver, A.; Dulgeroff, A.; Fraiz, J.; Friedlander, A.; Galvez, A.; Jani, C.; Johnson, S.; Khandelwal, P.; Kingsley, E.; Kingsley, J.; Hutchinson, L.; Lavender, R.; Lyons, R.; Guzley, G.; Martinez, R.; Metjian, A.; Moran, J.; Nadar, V.; Pish, R.; Pullman, J.; Quaranta, A. J.; Ravi, C.; Refaai, M.; Rehm, J.; Richards, D.; Richwine, R.; Sachdeva, S.; Seibert, A.; Sharma, A.; Stricklin, D.; Tannenbaum, A.; Tin-U, C.; Vora, K.; Watkins, D.; Willms, D.

    2013-01-01

    BackgroundWhether the oral factor Xa inhibitor edoxaban can be an alternative to warfarin in patients with venous thromboembolism is unclear. MethodsIn a randomized, double-blind, noninferiority study, we randomly assigned patients with acute venous thromboembolism, who had initially received

  7. An unusual case of repeated venous air embolism during awake ...

    African Journals Online (AJOL)

    their experience of managing an unusual case of repeated VAE during both sides of burr-hole and electrode insertion in awake bilateral DBS surgery. Keywords: awake craniotomy, burr hole, deep brain stimulation, neurosurgery, venous air embolism. Introduction. Venous air embolism (VAE) is the entrainment of air from a.

  8. Risk Factors of Deep Venous Thrombosis in Duplex and Colour ...

    African Journals Online (AJOL)

    Background: Deep venous thrombosis is a major health problem with high morbidity and mortality worldwide. Thus early, correct and definitive diagnosis is crucial in assessing thromboembolic risk and initiating therapy. In this regard Patients at risk must be identified and given appropriate prophylaxis to reduce Venous ...

  9. [Patient's consent to central venous catheterization].

    Science.gov (United States)

    Fiorini, F; Palumbo, G; Ciliberti, R

    2004-01-01

    The need to obtain a patient's consent for his health care is a principle set out in the Italian Constitution, which safeguards a person's right to health. Articles 13 and 32.2 confirm a person's freedom and the right to make free decisions about one's medical treatment. Nobody must be obliged to any medical procedure, unless as by law enacted. The obligation to inform patients is important during the contractual phase: consent is an essential element in the professional contract governing the relationship between a physician and a patient. The former is obligated to inform the latter about his medical intervention clearly and precisely, to enable the patient to decide freely whether to undergo a medical procedure. At this point, it is also essential to obtain a patient's consent for those treatments that although they are carried out in a correct and careful way, could damage a person's physical integrity. The failure to obtain consent could give rise to a burden of responsibility on behalf of the clinician. A central venous catheterization in hemodialysis (HD) is a common procedure performed during routine nephrological treatments. Our signed informed consent form prior to introducing a central venous catheter is thought to satisfy requirements provided for in current regulations to give correct information.

  10. Compression Stockings for Treating Venous Leg Ulcers

    Directory of Open Access Journals (Sweden)

    J. P. Benigni

    2013-01-01

    Full Text Available Background. In order to treat venous leg ulcers, it is recommended to use high pressure compression (30–40 mmHg at the ankle. Compression stockings which are not operator dependant could be the best option because of their pressure control. However 30–40 mmHg compression stockings are often hard to put on. Putting two lower pressure compression stockings over each other could be a good therapeutic alternative. Objectives. To compare the in vitro pressures given by the manufacturers of 2 antiulcer kits with the in vivo interface pressures measured in healthy subjects and to evaluate the stiffness and friction indices from those kits based on the interface pressure in order to assess their clinical properties. Material and Methods. Using a Kikuhime pressure device, interface pressure was measured in 12 healthy subjects at the reference point B1. One stiffness index (Static Stiffness Index (SSI and a friction index have been calculated. Results. Mediven Ulcer kit gets the recommended pressures whereas Jobst’s Ulcer Care kit does not for treating a venous leg ulcer. Jobst’s Ulcer Care transmits entirely the pressure in relation to a friction index close to 1. Conclusion. This antiulcer kit study underlines that in vivo and in vitro pressures can be different (Jobst’s Ulcer Care kit and Mediven Ulcer kit. In order not to lose pressure, it is important to take into account the friction index when superimposing two stockings.

  11. [Prophylaxis of Recurrent Venous Leg Ulcer].

    Science.gov (United States)

    Kroeger, K; Storck, M; Kujath, P; Rabe, E; Dissemond, J

    2017-06-01

    Venous leg ulcer (VLU) counts among the most common chronic wounds in Europe. Treatment is lengthy, cumbersome and costly, and there is a high rate of recurrence. This review shows the measures that should be offered to every patient with healed VLU to permanently prevent recurrence. To prevent VLU in case of varicose veins, the progression of chronic venous insufficiency (CVI) has to be stopped. There is convincing evidence that the effective treatment of varicose veins reduces the recurrence rate in patients with VLU. In patients with post-thrombotic syndrome (PTS), further thrombosis should be prevented through targeted prophylaxis of new thromboembolic events. The benefit of endovascular revascularization on the VLU recurrence rate in patients with post-thrombotic damage in the pelvic veins has not been proven in clinical studies. On the other hand, it has been clearly demonstrated in several studies that compression therapy is the basic procedure for the prevention of recurrent VLU in patients with varicose veins or PTS, regardless of whether other measures have been implemented or not. Good adherence in patients with compression therapy is more important than choosing the highest possible compression class. Future efforts for patients with VLU must aim to provide therapists with tools and treatment strategies to guide their patients and to increase patients' acceptance and understanding of the importance of self-management, in particular regarding compression therapy for the prevention of recurrent VLU. Georg Thieme Verlag KG Stuttgart · New York.

  12. INFLUENCE OF MOTOR CAPABILITIES ON EFFICACY IN PERFORMING WEDGE TURNING IN ALPINE SKIING

    Directory of Open Access Journals (Sweden)

    Rašid Hadžić

    2012-09-01

    Full Text Available Goal of this research is to fortify a degree of influence of motor capabilities on efficacy in performing wedge turning in alpine skiing. Research has been conducted on sample of 30 students, average age 22 years, gender-male, 9 motor tests. From derived results come that motor capabilities in showing space have significant influence on successfulness in performing elements of alpine skiing.

  13. 2D Traveling Wave Array Employing a Trapezoidal Dielectric Wedge for Beam Steering

    Science.gov (United States)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranada, Felix A.

    2014-01-01

    This presentation addresses the progress made so far in the development of an antenna array with reconfigurable transmission line feeds connecting each element in series. In particular, 2D traveling wave array employing trapezoidal Dielectric Wedge for Beam Steering will be discussed. The presentation includes current status of the effort and suggested future work. The work is being done as part of the NASA Office of the Chief Technologist's Space Technology Research Fellowship (NSTRF).

  14. Clinical effects of lateral wedge arch support insoles in knee osteoarthritis

    OpenAIRE

    Hsieh, Ru-Lan; Lee, Wen-Chung

    2016-01-01

    Abstract We compared the short-term efficacy of rigid versus soft lateral wedge arch support (LWAS) insoles for patients with knee osteoarthritis (OA), as assessed using the International Classification of Functioning, Disability and Health (ICF) system, through a prospective, double-blind, randomized controlled trial. Participants who fulfilled the combined radiographic and clinical criteria for knee OA, as defined by the American College of Rheumatology, were randomly prescribed 1 pair of r...

  15. Deciphering assumptions about stepped wedge designs: the case of Ebola vaccine research.

    Science.gov (United States)

    Doussau, Adélaïde; Grady, Christine

    2016-12-01

    Ethical concerns about randomising persons to a no-treatment arm in the context of Ebola epidemic led to consideration of alternative designs. The stepped wedge (SW) design, in which participants or clusters are randomised to receive an intervention at different time points, gained popularity. Common arguments in favour of using this design are (1) when an intervention is likely to do more good than harm, (2) all participants should receive the experimental intervention at some time point during the study and (3) the design might be preferable for practical reasons. We examine these assumptions when considering Ebola vaccine research. First, based on the claim that a stepped wedge design is indicated when it is likely that the intervention will do more good than harm, we reviewed published and ongoing SW trials to explore previous use of this design to test experimental drugs or vaccines, and found that SW design has never been used for trials of experimental drugs or vaccines. Given that Ebola vaccines were all experimental with no prior efficacy data, the use of a stepped wedge design would have been unprecedented. Second, we show that it is rarely true that all participants receive the intervention in SW studies, but rather, depending on certain design features, all clusters receive the intervention. Third, we explore whether the SW design is appealing for feasibility reasons and point out that there is significant complexity. In the setting of the Ebola epidemic, spatiotemporal variation may have posed problematic challenges to a stepped wedge design for vaccine research. Finally, we propose a set of points to consider for scientific reviewers and ethics committees regarding proposals for SW designs. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  16. Muon Intensity Increase by Wedge Absorbers for Low-E Muon Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, D. V. [Fermilab; Stratakis, D. [Fermilab; Bradley, J. [Fermilab

    2017-09-01

    Low energy muon experiments such as mu2e and g-2 have a limited energy spread acceptance. Following techniques developed in muon cooling studies and the MICE experiment, the number of muons within the desired energy spread can be increased by the matched use of wedge absorbers. More generally, the phase space of muon beams can be manipulated by absorbers in beam transport lines. Applications with simulation results are presented.

  17. Stratification and salt-wedge in the Seomjin river estuary under the idealized tidal influence

    Science.gov (United States)

    Hwang, Jin Hwan; Jang, Dongmin; Kim, Yong Hoon

    2017-09-01

    Advection, straining, and vertical mixing play primary roles in the process of estuarine stratification. Estuaries can be classified as salt-wedge, partially-mixed or well-mixed depending on the vertical density structure determined by the balancing of advection, mixing and straining. In particular, straining plays a major role in the stratification of the estuarine water body along the estuarine channel. Also, the behavior of a salt wedge with a halocline shape in a stratified channel can be controlled by the competition between straining and mixing induced by buoyancy from the riverine source and tidal forcing. The present study uses Finite Volume Coastal Ocean Model (FVCOM) to show that straining and vertical mixing play major roles in controlling along-channel flow and stratification structures in the Seomjin river estuary (SRE) under idealized conditions. The Potential Energy Anomaly (PEA) dynamic equation quantifies the governing processes thereby enabling the determination of the stratification type. By comparing terms in the equation, we examined how the relative strengths of straining and mixing alter the stratification types in the SRE due to changes in river discharge and the depth resulting from dredging activities. SRE under idealized tidal forcing tends to be partially-mixed based on an analysis of the balance between terms and the vertical structure of salinity, and the morphological and hydrological change in SRE results in the shift of stratification type. While the depth affects the mixing, the freshwater discharge mainly controls the straining, and the balance between mixing and straining determines the final state of the stratification in an estuarine channel. As a result, the development and location of a salt wedge along the channel in a partially mixed and highly stratified condition is also determined by the ratio of straining to mixing. Finally, our findings confirm that the contributions of mixing and straining can be assessed by using the

  18. Global typology of urban energy use and potentials for an urbanization mitigation wedge

    OpenAIRE

    Creutzig, F.; Baiocchi, G.; Bierkandt, R.; Pichler, P.-P.; Seto, K.C.

    2015-01-01

    Many case studies of specific cities have investigated factors that contribute to urban energy use and greenhouse-gas emissions. The analysis in this study is based on data from 274 cities and three global datasets and provides a typology of urban attributes of energy use. The results highlight that appropriate policies addressing urban climate change mitigation differ with type of city. A global urbanization wedge, corresponding in particular to energy-efficient urbanization in Asia, might r...

  19. Dehydration of chlorite explains anomalously high electrical conductivity in the mantle wedges.

    Science.gov (United States)

    Manthilake, Geeth; Bolfan-Casanova, Nathalie; Novella, Davide; Mookherjee, Mainak; Andrault, Denis

    2016-05-01

    Mantle wedge regions in subduction zone settings show anomalously high electrical conductivity (~1 S/m) that has often been attributed to the presence of aqueous fluids released by slab dehydration. Laboratory-based measurements of the electrical conductivity of hydrous phases and aqueous fluids are significantly lower and cannot readily explain the geophysically observed anomalously high electrical conductivity. The released aqueous fluid also rehydrates the mantle wedge and stabilizes a suite of hydrous phases, including serpentine and chlorite. In this present study, we have measured the electrical conductivity of a natural chlorite at pressures and temperatures relevant for the subduction zone setting. In our experiment, we observe two distinct conductivity enhancements when chlorite is heated to temperatures beyond its thermodynamic stability field. The initial increase in electrical conductivity to ~3 × 10(-3) S/m can be attributed to chlorite dehydration and the release of aqueous fluids. This is followed by a unique, subsequent enhancement of electrical conductivity of up to 7 × 10(-1) S/m. This is related to the growth of an interconnected network of a highly conductive and chemically impure magnetite mineral phase. Thus, the dehydration of chlorite and associated processes are likely to be crucial in explaining the anomalously high electrical conductivity observed in mantle wedges. Chlorite dehydration in the mantle wedge provides an additional source of aqueous fluid above the slab and could also be responsible for the fixed depth (120 ± 40 km) of melting at the top of the subducting slab beneath the subduction-related volcanic arc front.

  20. Increased venous thrombosis incidence in pregnancies after in vitro fertilization

    DEFF Research Database (Denmark)

    Hansen, Anette Tarp; Kesmodel, U S; Juul, S

    2014-01-01

    STUDY QUESTION Is venous thrombosis risk increased in pregnancies after in vitro fertilization? SUMMARY ANSWER The venous thrombosis incidence was significantly increased in pregnancies after in vitro fertilization; especially in the first trimester and in the first 6 weeks post-partum. WHAT...... IS KNOWN ALREADY In vitro fertilization without pregnancy is not associated with increased venous thrombosis incidence. STUDY DESIGN, SIZE, DURATION This national register-based cohort study covered the period from 1995 to 2005. PARTICIPANTS/MATERIALS, SETTING, METHODS All Danish pregnancies conceived...... by in vitro fertilization (n = 18 787) were included. Venous thrombosis incidence rates in pregnancies after in vitro fertilization were compared with venous thrombosis incidence rates in reference pregnancies, by calculating incidence rate ratios. MAIN RESULTS AND THE ROLE OF CHANCE In total, 48 cases were...

  1. Pulses of earthquake activity in the mantle wedge track the route of slab fluid ascent

    Science.gov (United States)

    White, Lloyd; Rawlinson, Nicholas; Lister, Gordon; Tanner, Dominique; Macpherson, Colin; Morgan, Jason

    2016-04-01

    Earthquakes typically record the brittle failure of part of the Earth at a point in space and time. These almost invariably occur within the crust or where the upper surface of subducting lithosphere interacts with the overriding mantle. However, there are also reports of rare, enigmatic earthquakes beneath rifts, above mantle plumes or very deep in the mantle. Here we report another type of mantle earthquake and present three locations where earthquake clusters occur in the mantle wedge overlying active subduction zones. These earthquake clusters define broadly circular to ellipsoidal columns that are 50 km or greater in diameter from depths between ~150 km and the surface. We interpret these rare pulses of earthquakes as evidence of near vertical transport of fluids (and associated flux-melts) from the subducted lithosphere through the mantle wedge. Detailed temporal analysis shows that most of these earthquakes occur over two-year periods, with the majority of events occurring in discrete month-long flurries of activity. As the time and location of each earthquake is recorded, pulses of seismic activity may provide information about the rate of magma ascent from the dehydrated subducted slab to sub-arc/backarc crust. This work indicates that fluids are not transported through the mantle wedge by diapirism, but through sub-vertical pathways facilitated by fracture networks and dykes on monthly to yearly time scales. These rare features move us toward solving what has until now represented a missing component of the subduction factory.

  2. Bacciger bacciger (Trematoda: Fellodistomidae) infection effects on wedge clam Donax trunculus condition.

    Science.gov (United States)

    de Montaudouin, Xavier; Bazairi, Hocein; Mlik, Karima Ait; Gonzalez, Patrice

    2014-10-16

    Wedge clams Donax trunculus inhabit high-energy environments along sandy coasts of the northeastern Atlantic Ocean and the Mediterranean Sea. Two sites were sampled monthly, one in Morocco (Mehdia), where the density was normal, and one in France (Biscarosse), where the density was very low. We tested the hypothesis that the difference in density between the sites was related to infection by the trematode parasite Bacciger bacciger. Identity of both the parasite and the host were verified using anatomical and molecular criteria. Parasite prevalence (i.e. the percentage of parasitized clams) was almost 3 times higher at Biscarosse. At this site, overall prevalence reached 32% in July and was correlated with the migration of several individuals (with a prevalence of 88%) to the sediment surface. After this peak, prevalence decreased rapidly, suggesting death of parasitized clams. The deleterious effect of B. bacciger on wedge clams was also supported by our calculations indicating that the weight of the parasite made up to 56% of the total weight of the parasitized clams. However, condition indices of trematode-free clams were also lower in Biscarosse than in Mehdia or other sites, suggesting that other factors such as pollutants or microparasites (Microcytos sp.) may alter wedge clam population fitness in Biscarosse.

  3. Exploring postoperative outcomes for ingrown toenails. NaOH vs wedge resection techniques.

    Science.gov (United States)

    Pérez-Rey, Jorge; Mediavilla-Saldaña, Lazaro; Martínez-Nova, Alfonso

    2014-03-01

    Ingrown (or ingrowing) toenail is a commonly used term for onychocryptosis, in which the nail becomes inserted into the lateral fold of the toe. The resulting effect on a person's health, well-being, and ability to work suggests the importance of clear treatment guidance, but little consensus exists. To explore postoperative recovery after surgery for ingrown toenails using chemical (sodium hydroxide (NaOH)) or mechanical (wedge resection) matricectomy and thus contribute to understanding within the field on which to base treatment guidelines. One hundred sixty-one procedures were undertaken, 94 using NaOH and 67 using wedge resection. Four measures of postoperative recovery were recorded: recurrence, infection, time to discharge, and number of postoperative visits. Patients treated with NaOH had lower rates of recurrence (p = .048) and infection (p = .03) than those treated with wedge resection, and time to discharge was shorter (p = .02), but they had more postoperative visits (p = .003). Low rates of recurrence and infection and short postoperative recovery time were found after both procedures, with a small advantage with treatment with NaOH. The authors argue for the value of clinical intervention using matricectomy in early stages to avoid complications resulting from granulation tissue growth. © 2014 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

  4. CFD Simulations of the IHF Arc-Jet Flow: Compression-Pad/Separation Bolt Wedge Tests

    Science.gov (United States)

    Goekcen, Tahir; Skokova, Kristina A.

    2017-01-01

    This paper reports computational analyses in support of two wedge tests in a high enthalpy arc-jet facility at NASA Ames Research Center. These tests were conducted using two different wedge models, each placed in a free jet downstream of a corresponding different conical nozzle in the Ames 60-MW Interaction Heating Facility. Each panel test article included a metallic separation bolt imbedded in Orion compression-pad and heatshield materials, resulting in a circular protuberance over a flat plate. The protuberances produce complex model flowfields, containing shock-shock and shock-boundary layer interactions, and multiple augmented heating regions on the test plate. As part of the test calibration runs, surface pressure and heat flux measurements on water-cooled calibration plates integrated with the wedge models were also obtained. Surface heating distributions on the test articles as well as arc-jet test environment parameters for each test configuration are obtained through computational fluid dynamics simulations, consistent with the facility and calibration measurements. The present analysis comprises simulations of the nonequilibrium flowfield in the facility nozzle, test box, and flowfield over test articles, and comparisons with the measured calibration data.

  5. CFD Simulations of the IHF Arc-Jet Flow: Compression-Pad Separation Bolt Wedge Tests

    Science.gov (United States)

    Gokcen, Tahir; Skokova, Kristina A.

    2017-01-01

    This paper reports computational analyses in support of two wedge tests in a high enthalpy arc-jet facility at NASA Ames Research Center. These tests were conducted using two different wedge models, each placed in a free jet downstream of a corresponding different conical nozzle in the Ames 60-MW Interaction Heating Facility. Each panel test article included a metallic separation bolt imbedded in Orion compression-pad and heatshield materials, resulting in a circular protuberance over a flat plate. The protuberances produce complex model flowfields, containing shock-shock and shock-boundary layer interactions, and multiple augmented heating regions on the test plate. As part of the test calibration runs, surface pressure and heat flux measurements on water-cooled calibration plates integrated with the wedge models were also obtained. Surface heating distributions on the test articles as well as arc-jet test environment parameters for each test configuration are obtained through computational fluid dynamics simulations, consistent with the facility and calibration measurements. The present analysis comprises simulations of the non-equilibrium flow field in the facility nozzle, test box, and flow field over test articles, and comparisons with the measured calibration data.

  6. Analysis and design of wedge projection display system based on ray retracing method.

    Science.gov (United States)

    Lee, Chang-Kun; Lee, Taewon; Sung, Hyunsik; Min, Sung-Wook

    2013-06-10

    A design method for the wedge projection display system based on the ray retracing method is proposed. To analyze the principle of image formation on the inclined surface of the wedge-shaped waveguide, the bundle of rays is retraced from an imaging point on the inclined surface to the aperture of the waveguide. In consequence of ray retracing, we obtain the incident conditions of the ray, such as the position and the angle at the aperture, which provide clues for image formation. To illuminate the image formation, the concept of the equivalent imaging point is proposed, which is the intersection where the incident rays are extended over the space regardless of the refraction and reflection in the waveguide. Since the initial value of the rays arriving at the equivalent imaging point corresponds to that of the rays converging into the imaging point on the inclined surface, the image formation can be visualized by calculating the equivalent imaging point over the entire inclined surface. Then, we can find image characteristics, such as their size and position, and their degree of blur--by analyzing the distribution of the equivalent imaging point--and design the optimized wedge projection system by attaching the prism structure at the aperture. The simulation results show the feasibility of the ray retracing analysis and characterize the numerical relation between the waveguide parameters and the aperture structure for on-axis configuration. The experimental results verify the designed system based on the proposed method.

  7. Plastic ingestion by Newell's (Puffinus newelli) and wedge-tailed shearwaters (Ardenna pacifica) in Hawaii.

    Science.gov (United States)

    Kain, Elizabeth C; Lavers, Jennifer L; Berg, Carl J; Raine, André F; Bond, Alexander L

    2016-12-01

    The ingestion of plastic by seabirds has been used as an indicator of pollution in the marine environment. On Kaua'i, HI, USA, 50.0 % of Newell's (Puffinus newelli) and 76.9 % of wedge-tailed shearwater (Ardenna pacifica) fledglings necropsied during 2007-2014 contained plastic items in their digestive tract, while 42.1 % of adult wedge-tailed shearwaters had ingested plastic. For both species, the frequency of plastic ingestion has increased since the 1980s with some evidence that the mass and the number of items ingested per bird have also increased. The color of plastic ingested by the shearwaters was assessed relative to beach-washed plastics by using Jaccard's index (where J = 1 complete similarity). The color (J = 0.65-0.68) of items ingested by both species, and the type ingested by wedge-tailed shearwaters (J = 0.85-0.87), overlapped with plastic available in the local environment indicating moderate selection for plastic color and type. This study has shown that the Hawaiian populations of shearwaters, like many seabird species, provide useful but worrying insights into plastic pollution and the health of our oceans.

  8. Analysis of Mechanical Energy Transport on Free-Falling Wedge during Water-Entry Phase

    Directory of Open Access Journals (Sweden)

    Wen-Hua Wang

    2012-01-01

    Full Text Available For better discussing and understanding the physical phenomena and body-fluid interaction of water-entry problem, here mechanical-energy transport (wedge, fluid, and each other of water-entry model for free falling wedge is studied by numerical method based on free surface capturing method and Cartesian cut cell mesh. In this method, incompressible Euler equations for a variable density fluid are numerically calculated by the finite volume method. Then artificial compressibility method, dual-time stepping technique, and Roe's approximate Riemann solver are applied in the numerical scheme. Furthermore, the projection method of momentum equations and exact Riemann solution are used to calculate the fluid pressure on solid boundary. On this basis, during water-entry phase of the free-falling wedge, macroscopic energy conversion of overall body-fluid system and microscopic energy transformation in fluid field are analyzed and discussed. Finally, based on test cases, many useful conclusions about mechanical energy transport for water entry problem are made and presented.

  9. Dose conformation to the spine during palliative treatments using dynamic wedges

    Energy Technology Data Exchange (ETDEWEB)

    Ormsby, Matthew A., E-mail: Matthew.Ormsby@usoncology.com [West Texas Cancer Center at Medical Center Hospital, Odessa, TX (United States); Herndon, R. Craig; Kaczor, Joseph G. [West Texas Cancer Center at Medical Center Hospital, Odessa, TX (United States)

    2013-07-01

    Radiation therapy is commonly used to alleviate pain associated with metastatic disease of the spine. Often, isodose lines are manipulated using dynamic or physical wedges to encompass the section of spine needing treatment while minimizing dose to normal tissue. We will compare 2 methods used to treat the entire thoracic spine. The first method treats the thoracic spine with a single, nonwedged posterior-anterior (PA) field. Dose is prescribed to include the entire spine. Isodose lines tightly conform to the top and bottom vertebrae, but vertebrae between these 2 received more than enough coverage. The second method uses a combination of wedges to create an isodose line that mimics the curvature of the thoracic spine. This “C”-shaped curvature is created by overlapping 2 fields with opposing dynamic wedges. Machine constraints limit the treatment length and therefore 2 isocenters are used. Each of the 2 PA fields contributes a portion of the total daily dose. This technique creates a “C”-shaped isodose line that tightly conforms to the thoracic spine, minimizing normal tissue dose. Spinal cord maximum dose is reduced, as well as mean dose to the liver, esophagus, and heart.

  10. The chronology of Late Pleistocene thermal contraction cracking derived from sand wedge OSL dating in central and southern France

    Science.gov (United States)

    Andrieux, Eric; Bateman, Mark D.; Bertran, Pascal

    2018-03-01

    Much of France remained unglaciated during the Late Quaternary and was subjected to repeated phases of periglacial activity. Numerous periglacial features have been reported but disentangling the environmental and climatic conditions they formed under, the timing and extent of permafrost and the role of seasonal frost has remained elusive. The primary sandy infillings of relict sand-wedges and composite-wedge pseudomorphs record periglacial activity. As they contain well-bleached quartz-rich aeolian material they are suitable for optically stimulated luminescence dating (OSL). This study aims to reconstruct when wedge activity took place in two regions of France; Northern Aquitaine and in the Loire valley. Results from single-grain OSL measurements identify multiple phases of activity within sand wedges which suggest that wedge activity in France occurred at least 11 times over the last 100 ka. The most widespread events of thermal contraction cracking occurred between ca. 30 and 24 ka (Last Permafrost Maximum) which are concomitant with periods of high sand availability (MIS 2). Although most phases of sand-wedge growth correlate well with known Pleistocene cold periods, the identification of wedge activity during late MIS 5 and the Younger Dryas strongly suggests that these features do not only indicate permafrost but also deep seasonal ground freezing in the context of low winter insolation. These data also suggest that the overall young ages yielded by North-European sand-wedges likely result from poor record of periglacial periods concomitant with low sand availability and/or age averaging inherent with standard luminescence methods.

  11. New angle measurement device to control the posterior tibial slope angle in medial opening wedge high tibial osteotomy.

    Science.gov (United States)

    Ogawa, Hiroyasu; Matsumoto, Kazu; Akiyama, Haruhiko

    2017-11-17

    Medial opening wedge high tibial osteotomy has been associated with an unintentional increase in the posterior tibial slope angle. We aimed to evaluate the effectiveness of a novel bone spreader angle rod to maintain the native posterior tibial slope angle in medial opening wedge high tibial osteotomy. Data from 92 consecutive knees in 83 patients who underwent medial opening wedge high tibial osteotomy for knee osteoarthritis between March 2015 and June 2016 were analysed. The osteotomy was performed without the use of a bone spreader angle rod in the first 50 cases (control group) and with the use of the angle rod in the subsequent 42 cases (angle rod group). The wedge insertion angle, defined as the angle between a line drawn along the posterior aspect of the wedge spacer and a line tangential to the posterior aspect of the femoral condyles, and the posterior tibial slope angle were evaluated on pre- and postoperative lateral knee radiographs and postoperative computed tomography images. Wedge insertion angle showed that wedge spacers were inserted in a more direct horizontal direction in the angle rod group than in the control group (16.0 ± 8.8° and 23.0 ± 10.0°, respectively, P angle was significantly smaller in the angle rod group (0.6 ± 1.6°) compared to that in the control group (3.2 ± 3.2°; P angle > 3° (outlier) was identified in 1 case (2.4%) in the angle rod group compared to 27 cases in the control group (54.0%). The direct horizontal insertion of wedge spacers with the assistance of our novel bone spreader angle rod maintains the native posterior tibial slope angle better than conventional methods. IV.

  12. THE AZYGOS VENOUS SYSTEM AND ITS ANATOMICAL VARIATIONS

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    Madiki Sudhakara Rao

    2016-06-01

    Full Text Available AIMS AND OBJECTIVES Azygos veins are important cavocaval and portacaval junctions, which form a collateral circulation in caval vein occlusion and in portal hypertension, cirrhosis of liver. The unpaired azygos venous system consists of azygos vein, hemiazygos vein and accessory azygos vein. This system of veins, along with its mediastinal, bronchial and oesophageal tributaries drains most of the body wall of trunk, namely posterior abdominal and thoracic wall. Anatomical variations of this unpaired azygos venous system are clinically important. AIMS To study and report the occurrence of anatomical variations of the unpaired azygos venous system in the region of East Godavari District, Andhra Pradesh (India. METHODS The present study was carried out in the Department of Anatomy, KIMS & RF, Amalapuram and G.S.L. Medical College, Rajahmundry over a period of 2 years. The present study was conducted on 60 cadavers (irrespective of age and sex. The entire course of the azygos venous system in these 60 cadavers was carefully observed and documented. RESULTS Anatomical variations were present in 16.66% of cases, out of which three distinct types were identified. 6.6% exhibited two separate azygos venous systems with no communications, 5% with communication between the left brachiocephalic vein and the azygos vein and 5% presence of post-aortic venous channels. CONCLUSION Variations of azygos venous system may be wrongly dubbed as aneurysm, lymphadenopathy or other abnormalities while reporting a CT scan of mediastinum. Venous anomalies are also detected only during surgery. The most troublesome intraoperative hazard is haemorrhage, which is mainly of venous origin. To avoid such situations is to have an awareness and knowledge of the expected venous anomalies.

  13. Association of varicosities and concomitant deep venous thrombosis in patients with superficial venous thrombosis, a systematic review

    NARCIS (Netherlands)

    Baggen, Vivan J M; Chung, Kaman; Koole, Koos; Sarneel, Michelle H J; Rutten, Frans H|info:eu-repo/dai/nl/189152753; Hajer, Gideon R

    2015-01-01

    BACKGROUND: In patients with superficial venous thrombosis (SVT) co-existence of deep venous thrombosis (DVT) can be present. Varicosities are considered as a risk factor for both SVT and DVT separately. However, current evidence is contradictory whether varicosities are associated with an increased

  14. Penile venous surgery for treating erectile dysfunction: Past, present, and future perspectives with regard to new insights in venous anatomy

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    Cheng-Hsing Hsieh

    2016-06-01

    Full Text Available In the physiologic model of normal erectile function, a healthy veno-occlusive mechanism is essential to initiate and maintain a rigid erection. The surgical treatment of patients with venous leakage, which is synonymous with corporoveno-occlusive dysfunction (CVOD, was based on the decreased venous outflow during the erection process. The initial reports of short-term results were promising, but the long-term benefits of penile venous ligation surgery were limited. Most clinical guideline panels concluded that surgeries performed in an attempt to limit the venous outflow of the penis were not recommended. Consequently, this surgery was nearly abandoned in most medical societies worldwide. These unfavorable postoperative outcomes seemed attributable to the indispensable usage of electrocautery and insufficient venous management, based on conventional penile venous anatomy. Advances in better understanding of human penile venous anatomy has enabled the development of refined penile venous stripping surgery. The thorough stripping surgery is an even more radical procedure, which is an even more radical procedure, and seems to be a viable option for the treatment of CVOD, however, there is still a need for further study with well-defined diagnostic criteria, and standardized patient and partner outcome assessment.

  15. High spatial resolution magnetic resonance imaging of experimental cerebral venous thrombosis with a blood pool contrast agent.

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    Spuentrup, E; Wiethoff, A J; Parsons, E C; Spangenberg, P; Stracke, C P

    2010-06-01

    The purpose of this study was to investigate the feasibility of clot visualization in small sinus and cortical veins with contrast enhanced MRA in a cerebral venous thrombosis animal model using a blood pool contrast agent, Gadofosveset, and high spatial resolution imaging. For induction of cerebral venous thrombosis a recently developed combined interventional and microsurgical model was used. Cerebral sinus and cortical vein thrombosis was induced in six pigs. Two further pigs died during the procedure. Standard structural, time-of-flight- and phase contrast-angiograms were followed by fast time resolved high resolution 3D MRA (4D MRA) and subsequent high spatial resolution 3D MRA in the equilibrium phase with and without addition of parallel imaging. Visualization of the clots using the different sequences was subjectively compared and contrast-to-noise ratio (CNR) was assessed. In the remaining six animals the procedure and MR-imaging protocol including administration of Gadofosveset was successfully completed. The 3D high resolution MRA in the equilibrium phase without the addition of parallel imaging was superior to all the other applied MR measurement techniques in terms of visualization of the clots. Only applying this sequence bridging vein thromboses were also seen as a small filling defect with a high CNR of >18. Only the non-accelerated high spatial resolution 3D MRA in the equilibrium in conjunction with the blood pool agent Gadofosveset allows for high-contrast visualization of very small clots in the cerebral sinus and cortical veins. STATEMENT CLINICAL IMPACT: Detection of cortical vein thrombosis is of high clinical impact. Conventional MRI sequences often fail to visualize the clot. We could demonstrate that, in contrast to conventional sequences, with high spatial resolution 3D MRA in the equilibrium in conjunction with the blood pool agent Gadofosveset very small clots in the cerebral sinus and cortical veins could be successfully visualized. We

  16. An IBEM solution to the scattering of plane SH-waves by a lined tunnel in elastic wedge space

    Science.gov (United States)

    Liu, Zhongxian; Liu, Lei

    2015-02-01

    The indirect boundary element method (IBEM) is developed to solve the scattering of plane SH-waves by a lined tunnel in elastic wedge space. According to the theory of single-layer potential, the scattered-wave field can be constructed by applying virtual uniform loads on the surface of lined tunnel and the nearby wedge surface. The densities of virtual loads can be solved by establishing equations through the continuity conditions on the interface and zero-traction conditions on free surfaces. The total wave field is obtained by the superposition of free field and scattered-wave field in elastic wedge space. Numerical results indicate that the IBEM can solve the diffraction of elastic wave in elastic wedge space accurately and efficiently. The wave motion feature strongly depends on the wedge angle, the angle of incidence, incident frequency, the location of lined tunnel, and material parameters. The waves interference and amplification effect around the tunnel in wedge space is more significant, causing the dynamic stress concentration factor on rigid tunnel and the displacement amplitude of flexible tunnel up to 50.0 and 17.0, respectively, more than double that of the case of half-space. Hence, considerable attention should be paid to seismic resistant or anti-explosion design of the tunnel built on a slope or hillside.

  17. Improvements of venous tone with pycnogenol in chronic venous insufficiency: an ex vivo study on venous segments.

    Science.gov (United States)

    Belcaro, Gianni; Dugall, Mark; Luzzi, Roberta; Hosoi, M; Corsi, Marcello

    2014-03-01

    This study evaluated the stretching and dilatation of venous segments ex vivo in subjects with primary varicose veins in comparison with comparable segments from subjects that used the supplement Pycnogenol (150 mg/d) for 3 months before surgery. Subjects with varicose veins and chronic venous insufficiency voluntarily used Pycnogenol for a period of at least 3 months. The segments of veins removed with surgery (in 30 subjects that had used Pycnogenol and in 10 comparable control subjects that had not used the supplement) were compared with normal, unused vein segments harvested for bypass grafting. The segments were suspended and a weight was attached to the distal part of the veins for 3 minutes and dilated with pressurized water. Digital images were recorded; the veins were measured before and after stretching to evaluate elongation. The manipulation of the vein segment was minimal. Tests were completed within 20 minutes after harvesting the veins. All segments were 4 cm long. The stretching test indicated a significantly higher level of passive elongation in control, varicose segments (2.29; 0.65 mm) in comparison with 1.39; 0.2 mm in vein segments from Pycnogenol-using patients. The dilation test showed an average higher dilation (2.19; 0.3 mm) in control varicose veins in comparison with varicose veins from Pycnogenol-using patients (1.32; 0.7 mm) (p Pycnogenol-using subjects (p Pycnogenol. Varicose segments had a more significant persistent dilatation and elongation in comparison with normal vein segments. Pycnogenol seems to decrease passive dilatation and stretching and gives vein walls a greater tonic recovery and elasticity that allows the vein to recover its original shape after dynamic stresses.

  18. Oral aspirin for treating venous leg ulcers.

    Science.gov (United States)

    de Oliveira Carvalho, Paulo Eduardo; Magolbo, Natiara G; De Aquino, Rebeca F; Weller, Carolina D

    2016-02-18

    Venous leg ulcers (VLUs) or varicose ulcers are the final stage of chronic venous insufficiency (CVI), and are the most common type of leg ulcer. The development of VLUs on ankles and lower legs can occur spontaneously or after minor trauma. The ulcers are often painful and exudative, healing is often protracted and recurrence is common. This cycle of healing and recurrence has a considerable impact on the health and quality of life of individuals, and healthcare and socioeconomic costs. VLUs are a common and costly problem worldwide; prevalence is estimated to be between 1.65% to 1.74% in the western world and is more common in adults aged 65 years and older. The main treatment for a VLU is a firm compression bandage. Compression assists by reducing venous hypertension, enhancing venous return and reducing peripheral oedema. However, studies show that it only has moderate effects on healing, with up to 50% of VLUs unhealed after two years of compression. Non-adherence may be the principal cause of these poor results, but presence of inflammation in people with CVI may be another factor, so a treatment that suppresses inflammation (healing ulcers more quickly) and reduces the frequency of ulcer recurrence (thereby prolonging time between recurrent episodes) would be an invaluable intervention to complement compression treatments. Oral aspirin may have a significant impact on VLU clinical practice worldwide. Evidence for the effectiveness of aspirin on ulcer healing and recurrence in high quality RCTs is currently lacking. To assess the benefits and harms of oral aspirin on the healing and recurrence of venous leg ulcers. In May 2015 we searched: The Cochrane Wounds Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE and EBSCO CINAHL. Additional searches were made in trial registers and reference lists of relevant publications for

  19. The "Wedge Sign": An Imaging Sign for Aggressive Lacrimal Gland Disease.

    Science.gov (United States)

    Lorenzano, Daniele; Rose, Geoffrey E

    2017-07-01

    Lacrimal gland carcinoma can form a triangle of tissue back to the orbital apex, intraconal spread apparently being prevented by the intermuscular septum. The "wedge sign" frequency is assessed in lacrimal carcinoma, lacrimal lymphoma, or dacryoadenitis. Retrospective masked review of images from patients with biopsy-proven lacrimal gland pathology. For each patient, the presence of a triangle of tissue between the lateral rectus and lateral orbital wall and the superior rectus and the orbital roof was assessed by masked review of computed tomography or magnetic resonance imaging. For the lateral compartment, the wedge was classified as "grade 1" if it just reached the sphenoidal trigone and "grade 2" if it was a complete triangle reaching the orbital apex. Comparison of proportions was made using the Fisher exact test, using an α risk of 0.05 as clinically significant. Imaging for 116 patients was reviewed: 39 with lacrimal gland carcinoma, 37 with lymphoma, and 40 with dacryoadenitis. The lateral wedge (grade 1 or 2) was most common in patients with carcinoma (16/39; 41%), was present in 11 of 37 patients (30%) with lymphoma, and was rarest in patients with dacryadenitis (6/40; 15%) (P = 0.033). The proportion in patients with carcinoma (41%) was similar to that in patients with lymphoma (30%) (P = 0.345); the proportion in patients with lymphoma (30%) was similar to that in patients with dacryoadenitis (15%) (P = 0.170), but carcinoma (41%) was significantly different from dacryoadenitis (15%) (P = 0.013). The proportions for malignant lesions (carcinoma and lymphoma; 27/76, 36%) and benign dacryoadenitis (15%) were significantly different (P = 0.029). Likewise, a superior wedge, of any extent, was present in 10 of 39 carcinomas (26%), 2 of 40 dacryoadenitis (5%), and 6 of 37 lymphomas (16%) (P = 0.033). The "wedge sign" is most common in lacrimal gland carcinoma, but can occur in patients with severe forms of dacryoadenitis or lymphoma and generally

  20. Wedge resection for high astigmatism after penetrating keratoplasty for keratoconus: refractive and histopathologic changes.

    Science.gov (United States)

    de la Paz, María Fideliz; Sibila, Gimena Rojas; Montenegro, Gustavo; de Toledo, Juan Alvarez; Michael, Ralph; Barraquer, Rafael; Barraquer, Joaquin

    2010-06-01

    To analyze the refractive, topographic, keratometric changes and the histopathologic findings after wedge resection to correct high astigmatism after penetrating keratoplasty for keratoconus. A retrospective study was done analyzing the following parameters preoperatively and at 1, 3, and 5 years postoperatively: uncorrected visual acuity, best-corrected visual acuity, and spherical equivalent and refractive, topographic, and keratometric cylinder measures. We also studied the efficacy and safety indices, as well as the histopathologic findings of tissues submitted for pathology. A total of 22 eyes of 21 patients who underwent wedge resection in the host corneal tissue for correcting high irregular astigmatism after penetrating keratoplasty for keratoconus were included in the study. Mean follow-up time from penetrating keratoplasty to wedge resection was 18 years, whereas the mean follow-up time after wedge resection was 39.04 months (range, 12-280 months). The mean preoperative refractive, topographic, and keratometric cylinders were 11.58 +/- 3.52 diopters (D) (range, 4.5-20 D), 10.88 +/- 5.03 D (range, 2.58-21.3 D), and 11.29 +/- 4.33 D (range, 4.50-18 D), respectively. The mean postoperative refractive, topographic, and keratometric cylinders at 3 years were 4.91 +/- 2.48 D (range, 0.50-10 D), 3.38 +/- 2.10 D (range, 2.05-7.1 D), and 5.31 +/- 2.90 D (range, 0.50-9 D), respectively. The percentage of correction at 3 years of follow up was 57.5% for refractive cylinder, 68.97% for topographic cylinder, and 53.01% for keratometric cylinder. All refractive, topographic, and keratometric data showed the lowest degree of astigmatism at 3 years postoperatively, with a tendency toward regression at 5 years postoperatively. Safety index was 1.0, whereas efficacy index was 0.49. All histopathologic sections of resected tissue were consistent with keratoconus progression in the host peripheral cornea. Wedge resection is a safe and moderately effective procedure in the

  1. Formation of wedge-like pattern on VLF spectrograms observed by DEMETER

    Science.gov (United States)

    Shklyar, David; Parrot, Michel; Chum, Jaroslav; Santolik, Ondrej; Titova, Elena

    2010-05-01

    The DEMETER satellite has almost circular polar orbit, with the altitude ~ 700 km. At middle latitudes, DEMETER typically stays in the region where the height-dependent variation of the lower hybrid resonance (LHR) frequency profile forms a trough, i.e. inside the so-called LHR waveguide. In this region, LHR phenomena reveal themselves most distinctly. A striking example of such phenomena is provided by wedge-like events (WLE) registered sometimes on overview VLF spectrograms (time duration ~ 2 minutes, frequency range 0 - 20 kHz) during thunderstorm activity. A characteristic feature of these spectrograms is the presence of unusual upper and lower cutoff frequencies. The upper cutoff frequency varies rapidly, approximately in proportion to L-3, where L is McIlwain parameter on the satellite orbit. On the contrary, the lower cutoff frequency is almost constant, so that the cutoffs cross at larger L. Between these cutoffs, which thus form a wedge, intense whistlers are observed, whereas only 0+ whistlers and, probably, ducted whistlers are found outside the cutoffs. We present numerous examples of such spectrograms, and explain the formation of wedge-like structures by the wave propagation features in the inner magnetosphere, and specific position of the satellite with respect to the LHR maximum. In general terms, this explanation is as follows. WLE consists of whistler mode waves originating from lightnings and, thus, is related to thunderstorm activity. The wedge as such is formed by quasi-resonance whistler waves that cannot propagate in the region where the wave frequency is below local LHR frequency. Then, the lower frequency cutoff is determined by the LHR maximum, as quasi-resonant waves with lower frequencies originating in opposite hemisphere do not reach the satellite due to LHR reflection above it. The appearance of an upper cutoff frequency is due to another feature of unducted VLF wave propagation, which consists in trajectories merging into a limiting

  2. Obesity and lower limb venous disease - The epidemic of phlebesity.

    Science.gov (United States)

    Davies, Huw Ob; Popplewell, Matthew; Singhal, Rishi; Smith, Neil; Bradbury, Andrew W

    2017-05-01

    Introduction Lower limb venous disease affects up to one half, and obesity up to one quarter, of the adult population. Many people are therefore affected by, and present to health services for the treatment of both conditions. This article reviews the available evidence of pathophysiological and clinical relationship between obesity and varicose veins, chronic venous insufficiency and ulceration and deep vein thrombosis. Methods A literature search of PubMed and Cochrane libraries was performed in accordance with PRISMA statement from 1946 to 2015, with further article identification from following cited references for articles examining the relationship between obesity and venous disease. Search terms included obesity, overweight, thrombosis, varicose veins, CEAP, chronic venous insufficiency, treatment, endovenous, endothermal, sclerotherapy, bariatric surgery and deep vein thrombosis. Results The proportion of the population suffering from lower limb venous disease and obesity is increasing. Obesity is an important risk factor for all types of lower limb venous disease, and obese patients with lower limb venous disease are more likely to be symptomatic as a result of their lower limb venous disease. The clinical diagnosis, investigation, imaging and treatment of lower limb venous disease in obese people present a number of challenges. The evidence base underpinning medical, surgical and endovenous management of lower limb venous disease in obese people is limited and such treatment may be associated with worse outcomes and increased risks when compared to patients with a normal body mass index. Conclusion Lower limb venous disease and obesity are both increasingly common. As such, phlebologists will be treating ever greater numbers of obese patients with lower limb venous disease, and clinicians in many other specialties are going to be treating a wide range of obesity-related health problems in people with or at risk of lower limb venous disease. Unfortunately

  3. VENOUS INSUFFICIENCY AND THROMBOEMBOLIC DISEASE IN BARIATRIC SURGERY PATIENTS

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    Bonno van BELLEN

    2013-09-01

    Full Text Available Context Morbid obesity is associated with various co-morbidities, including chronic venous insufficiency. Bariatric surgery is the only effective treatment for morbid obesity, but with potential risks and possible complications, including venous thromboembolism. Objective To determine the prevalence of clinical and ultrasonographic signs of chronic venous insufficiency in morbid obese patients in preparation for bariatric surgery and the incidence of post-operative venous thromboembolic disease. Methods Patients on work-up for bariatric surgery of Centro Terapêutico Especializado em Fígado (CETEFI and Pro-Gastro surgical teams of the Hospital Beneficência Portuguesa de São Paulo were included. The analysed data were pre-operative findings for venous insufficiency (CEAP - clinical, etiological, anatomical, physiopathologic - classification and venous ultrassonographic findings, type of surgery (open or laparoscopic, abdominal circumference, body mass index (BMI and post-operative ultrassonography search for venous insufficiency and deep venous thrombosis. Results Between March 2007 and December 2009, 95 patients candidates for bariatric surgery had clinical and duplex scan evaluation of the lower limbs venous system. Of the 95 patients, 53 were submitted to the surgical procedure. There was a predominance of women (77.9%, the average age was 38.5 years, average preoperative weight 124.6 kg and average BMI of 45.5 kg/m2. Regarding obesity, 16.8% were obese, and 83.1% were morbidly obese. In relation to the venous findings, 86.3% of the patients did fit CEAP classification less than 3 and 13.7% greater than or equal to 3. Among the post-operative complications, there were four cases of wound infection. Three patients developed post-operative distal venous thrombosis (7.5%, but no one had clinically manifested pulmonary embolism. Conclusion No relation between BMI, CEAP classification and venous ultrassonographic findings were found. Although

  4. The relationship between mixed venous and hepatic venous O2 saturation in patients with septic shock.

    Science.gov (United States)

    Meier-Hellmann, A; Hannemann, L; Specht, M; Schaffartzik, W; Spies, C; Reinhart, K

    1994-01-01

    It was the purpose of this study to measure the relationship between hepatic venous O2 saturation (ShvO2) and mixed venous O2 saturation (SvO2) in septic patients (n = 21) following treatment with various catecholamines (epinephrine, norepinephrine, dopamine, dopexamine). At baseline mean SvO2 was 74 +/- 5% while mean ShvO2 was 59 +/- 12%. Alpha-mimetic substances such as epinephrine and norepinephrine reduced ShvO2 and increased the difference between SvO2 and ShvO2.Beta2-mimetic and dopaminergic substances (dopexamine, dopamine) did not change the difference between SvO2 and ShvO2. These results show that SvO2 does not necessarily reflect all changes of ShvO2. Monitoring ShvO2 may be helpful in managing septic shock by adding information on adequacy of O2 supply/consumption ratio in the crucial splanchnic region.

  5. Peripheral venous pressure as a predictor of central venous pressure in continuous monitoring in children.

    Science.gov (United States)

    Amoozgar, H; Ajami, Gh H; Borzuoee, M; Amirghofran, A A; Ebrahimi, P

    2011-05-01

    Measurement of central venous pressure (CVP) is a reliable method for evaluating intravascular volume status and cardiac function; however it is an invasive and expensive method that may result in some complications such as arterial puncture, pneumothorax and development of infections. This study was performedto compare CVP measurements between central and peripheral catheters in infant and children with congenital heart disease. The CVP and peripheral venous pressure (PVP) were measured simultaneously in 30 patients within 10 consecutive hours. The mean difference between CVP and PVP was 1.48±0.98 mmHg. The linear regression equation showed that CVP was 0.374+0.774 PVP (r(2) = 0.725). PVP measured from a peripheral intravenous catheter in infants and children with congenital heart disease is an accurate estimation of CVP and its changes has good concordance with CVP over a long period of time.

  6. Cerebral Venous Thrombosis and Venous Infarction: Case Report of a Rare Initial Presentation of Smoker's Polycythemia

    OpenAIRE

    Mihir Raval; Anu Paul

    2010-01-01

    Introduction: Cerebral venous thrombosis is a rare initial presentation of polycythemia. If diagnosed early, treatment can reduce mortality and morbidity significantly. Often it may present with headache as the only complaint, and thus the diagnosis is likely to be missed. Case Presentation: A medically stable 31-year-old male, a chronic smoker with a ∼17 pack-year history of smoking, was admitted to the emergency room with a 2-week history of gradually worsening, severe, throbbing headache i...

  7. [Monitoring of jugular venous oxygen saturation].

    Science.gov (United States)

    Nakamura, Shunsuke

    2011-04-01

    The continuous monitoring of jugular venous oxygen saturation(SjO2) has become a practical method for monitoring global cerebral oxygenation and metabolism. SjO2 reflects the balance between the cerebral blood flow and the cerebral metabolic rate for oxygen (CMRO2), if arterial oxyhemoglobin saturation, hemoglobin concentration remain constant. Normal SjO2 values range between 55% and 75%. Low SjO2 indicates cerebral hypoperfusion or ischemia. Conversely, an increased SjO2 indicates either cerebral hyperemia or a disorder that decreases CMRO2. In minimizing secondary brain damage following resuscitation from cardiopulmonary arrest, SjO2 monitoring is thus considered to be an integral part of multimodality monitoring and can provide important information for the management of patients in neurointensive care.

  8. VENOUS ULCER--A NEW THERAPEUTIC APPROACH.

    Science.gov (United States)

    Popa, R F; Cazan, I; Baroi, Genoveva; Cazan, Simona; Lefter, G; Strobescu, Cristina

    2016-01-01

    Trophic leg ulcer is a major health problem affecting approximately 1-2% of the population, the incidence being higher in the elderly (70-80 years). It is a multifactorial condition, but the most common cause is chronic venous insufficiency. This can be attributed to reflux in the saphenous system and calf perforator vein incompetence. These were first described by Linton, the first intervention designed to correct perforator vein incompetence bearing his name. Today Linton's operation has been abandoned due to the large unaesthetic incision and great postoperative pain. Also, ulcer healing time is long (2 months) and recurrence rate is high. Currently a series of minimally invasive procedures are used to close these perforator veins, such as ultrasound-guided sclerotherapy. The advantages of these techniques are less discomfort to the patients, low rate of complications, short hospital stay.

  9. A genetical approach to deep venous thrombosis

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    Celal Yavuz

    2012-06-01

    Full Text Available Deep venous thrombosis (DVT is a common disorderthat frequently occurs after surgical procedures andtrauma and in the presence of cancer or immobilizationconditions. However, it can also develop without any ofthese predisposing factors. This condition directs theresearcher’s enquiry to investigating the basis of organismalthrombotic predisposition. The common prothromboticgenetic mutations include factor V Leiden, factor IIG20210 A, plasminogen activator inhibitor-1, prothrombinA20210, and factor XIII - VIII. Nevertheless, current studiessuggest that the thrombotic events are not connectedwith single gene deletion or homeostatic regulation is alsoaffected by other genetic risk factors. Complex interactionsof genetic mutations can be affects different levels ofthrombotic system or reinforce each other’s effects on homeostaticmechanisms. The analysis of literature, togetherwith the action mechanisms of the classic geneticalfactors and new suggestions, may contribute significantlyto our understanding of the genetic predisposition to venousthrombosis. J Clin Exp Invest 2012; 3(2: 303-306

  10. Venous thromboembolism: have we made headway?

    Science.gov (United States)

    Fitzgerald, Jan

    2010-01-01

    Venous thromboembolism (VTE) is a primary cause of preventable hospital death. The need for effective VTE prophylaxis has been recognized by the Surgical Care Improvement Program (SCIP) and the Joint Commission, which is offering VTE prevention as a core measure set, starting October 1, 2009. The adoption of SCIP VTE measures and mandate to publicly report these rates offers the opportunity to improve the use of prophylaxis in surgical patients and reduce VTE-related morbidity, mortality, and costs. Essential to this reduction is a team approach to implementing real-time interventions. Crucial to the success of the team is early identification of each patient's VTE risk and a mechanism to provide key information to ensure that the physician prescribes appropriate prophylaxis. In addition, it may be the nurse who is responsible for ensuring that a patient receives the appropriate prophylaxis, as well as being the first clinician to observe the clinical signs of a VTE event.

  11. Provisional Matrix Deposition in Hemostasis and Venous Insufficiency: Tissue Preconditioning for Nonhealing Venous Ulcers

    Science.gov (United States)

    Parker, Tony J.; Broadbent, James A.; McGovern, Jacqui A.; Broszczak, Daniel A.; Parker, Christina N.; Upton, Zee

    2015-01-01

    Significance: Chronic wounds represent a major burden on global healthcare systems and reduce the quality of life of those affected. Significant advances have been made in our understanding of the biochemistry of wound healing progression. However, knowledge regarding the specific molecular processes influencing chronic wound formation and persistence remains limited. Recent Advances: Generally, healing of acute wounds begins with hemostasis and the deposition of a plasma-derived provisional matrix into the wound. The deposition of plasma matrix proteins is known to occur around the microvasculature of the lower limb as a result of venous insufficiency. This appears to alter limb cutaneous tissue physiology and consequently drives the tissue into a ‘preconditioned’ state that negatively influences the response to wounding. Critical Issues: Processes, such as oxygen and nutrient suppression, edema, inflammatory cell trapping/extravasation, diffuse inflammation, and tissue necrosis are thought to contribute to the advent of a chronic wound. Healing of the wound then becomes difficult in the context of an internally injured limb. Thus, interventions and therapies for promoting healing of the limb is a growing area of interest. For venous ulcers, treatment using compression bandaging encourages venous return and improves healing processes within the limb, critically however, once treatment concludes ulcers often reoccur. Future Directions: Improved understanding of the composition and role of pericapillary matrix deposits in facilitating internal limb injury and subsequent development of chronic wounds will be critical for informing and enhancing current best practice therapies and preventative action in the wound care field. PMID:25785239

  12. Correlation of central venous pressure with venous blood gas analysis parameters; a diagnostic study

    Directory of Open Access Journals (Sweden)

    Sima Rahim-Taleghani

    2017-03-01

    Full Text Available Objective: This study was conducted to assess the correlation between central venous pressure (CVP and venous blood gas (VBG analysis parameters, to facilitate management of severe sepsis and septic shock in emergency department. Material and methods: This diagnostic study was conducted from January 2014 until June 2015 in three major educational medical centers, Tehran, Iran. For patients selected with diagnosis of septic shock, peripheral blood sample was taken for testing the VBG parameters and the anion gap (AG was calculated. All the mentioned parameters were measured again after infusion of 500 cc of normal saline 0.9% in about 1 h. Results: Totally, 93 patients with septic shock were enrolled, 63 male and 30 female. The mean age was 72.53 ± 13.03 and the mean Shock Index (SI before fluid therapy was 0.79 ± 0.30. AG and pH showed significant negative correlations with CVP, While HCO3 showed a significant positive correlation with CVP. These relations can be affected by the treatment modalities used in shock management such as fluid therapy, mechanical ventilation and vasopressor treatment. Conclusion: It is likely that there is a significant statistical correlation between VBG parameters and AG with CVP, but further research is needed before implementation of the results of this study. Keywords: Shock, Septic, Central venous pressure, Blood gas analysis, Emergency department, Emergency medicine

  13. Peripheral venous pressure as a reliable predictor for monitoring central venous pressure in patients with burns.

    Science.gov (United States)

    Sherif, Lulu; Joshi, Vikas S; Ollapally, Anjali; Jain, Prithi; Shetty, Kishan; Ribeiro, Karl Sa

    2015-04-01

    Optimizing cardiovascular function to ensure adequate tissue oxygen delivery is a key objective in the care of critically ill patients with burns. Hemodynamic monitoring may be necessary to optimize resuscitation in serious burn patients with reasonable safety. Invasive central venous pressure (CVP) monitoring has become the corner stone of hemodynamic monitoring in patients with burns but is associated with inherent risks and technical difficulties. Previous studies on perioperative patients have shown that measurement of peripheral venous pressure (PVP) is a less invasive and cost-effective procedure and can reliably predict CVP. The aim of the present prospective clinical study was to determine whether a reliable association exists between changes in CVP and PVP over a long period in patients admitted to the Burns Intensive Care Unit (BICU). The CVP and PVP were measured simultaneously hourly in 30 burns patients in the BICU up to 10 consecutive hours. The predictability of CVP by monitoring PVP was tested by applying the linear regression formula and also using the Bland-Altman plots of repeated measures to evaluate the agreement between CVP and PVP. The regression formula revealed a reliable and significant association between CVP and PVP. The overall mean difference between CVP and PVP was 1.628 ± 0.84 mmHg (P venous pressure measured from a peripheral intravenous catheter in burns patients is a reliable estimation of CVP, and its changes have good concordance with CVP over a long period of time.

  14. [Maternal death by venous thromboembolic disease].

    Science.gov (United States)

    Rossignol, M; Morau, E; Dreyfus, M

    2017-12-01

    Pregnancy and postpartum are very high-risk periods for venous thromboembolism events (TEE), which seems to extend far beyond the classical 6-8 weeks after childbirth. Pulmonary embolism (PE) is one of the 3 main causes of direct maternal death in western countries. Between 2010 an 2012 in France, 24 deaths were related to PE giving a maternal mortality ratio of 1/100,000, which is not different from the former report (2007-2009). PE is responsible of 9% of maternal deaths, in equal position with postpartum hemorrhage and amniotic fluid embolism. Four deaths (16%) occurred after pregnancy interruption (1 abortion, 3 medical interruptions), 7 (30%) during ongoing pregnancy (before 22 weeks of pregnancy) and 13 (54%) in the postpartum period (9 to 60 days after childbirth). Among these deaths, 9 occurred in extra hospital setting (at home or in the street). Fifty percent of these deaths seem to be avoidable, as it was in the former report. Main avoidability criteria were: diagnostic delay; mobilization before effective anticoagulation of proximal deep venous thrombosis; insufficient preventive treatment with low molecular weight heparin [duration and/or dose (obesity)]; unjustified induction of labor. Analyzing those deaths allow to remind that in case of high suspicion of TEE, effective anticoagulation should be started without delay, and that angio-TDM is not contraindicated in pregnant women. Low molecular weight heparin regiment should be adapted to real weight. Monitoring of anti-Xa activity, if not routinely recommended, is probably useful in case of obesity or renal insufficiency. Anticipating birth by induction of labor, in the absence of abnormal fetal heart rhythm, should not delay effective anticoagulation of near-term TEE. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  15. [Oral anticoagulat treatment in venous thromboembolic disease].

    Science.gov (United States)

    Fontcuberta, Jordi

    2008-11-01

    Coumarin or anti-vitamin K oral anticoagulants have been used in anticoagulation therapy for more than 50 years. Well-designed studies have demonstrated the effectiveness of these drugs in the primary and secondary prevention of venous thromboembolic disease (VTD). Because of greater life expectancy and the increase in the indications for oral anticoagulation therapy (OAT), more and more patients are receiving this type of treatment. In Spain, approximately 1% of the population receives OAT. The mechanism of action of coumarin anticoagulants is based on inhibition of the interconversion of vitamin K and its 2,3-epoxide (vitamin K epoxide, which modulates gamma-carboxylation of the glutamic acid residues in the N-terminal regions of vitamin-K-dependent factors, namely, II, VII, IX, X, protein C, protein S and protein Z). Due to the lack of gamma-carboxylation, these factors lose their procoagulant activity. Major hemorrhagic complications of OAT in VTD after 3-6 months of treatment, with an INR of 2-3, occur in nearly 2% of patients. The hemorrhagic complications of OAT are related to the intensity of anticoagulation, patient characteristics, the concomitant use of drugs that interfere with hemostasis, and treatment duration. The risk of VTD recurrence after 3-6 months of OAT is high and can be more than 10% in patients with idiopathic thromboembolism or irreversible risk factors such as thrombophilia, cancer and other situations conferring permanent risk. The risk of recurrence is more frequent in men, in patients with thrombophilia especially in antithrombin deficiency, and in patients with cancer, residual venous obstruction, or elevated D dimer.

  16. [Association between venous thrombosis and dyslipidemia].

    Science.gov (United States)

    García Raso, Aránzazu; Ene, Gabriela; Miranda, Carolina; Vidal, Rosa; Mata, Raquel; Llamas Sillero, M Pilar

    2014-07-07

    Venous and arterial thrombosis, despite being historically considered as distinct conditions, share certain risk factors. Dyslipidemia is a clinical condition with a relatively high prevalence in the population and has been associated with an increased thrombotic risk. Lipids and lipoproteins modulate the expression and/or function of thrombotic, fibrinolytic and rheological factors. We have developed a descriptive, retrospective, comparative, cross-sectional study including a group of 313 patients with venous thromboembolism (VTE). We collected basic demographic data, cardiovascular risk factors and thrombotic complications. All patients were subjected to a lipid profile study with determination of total cholesterol, high density lipoprotein cholesterol (cHDL), low density lipoprotein cholesterol (cLDL) and triglycerides. The multivariable analysis showed that dyslipidemia was a risk factor for VTE (odds ratio [OR] 3.87, 95% confidence interval [95% CI] 2.72-5.56; P<.0001). Of a total of 313 patients included in the study, 31% (n=97) had a recurrent thrombotic event and 23% (n=72) developed post-thrombotic syndrome. cHDL levels below 35 mg/dl and cLDL levels higher than 180 mg/dl represented risk factors for the development of recurrent thrombosis, OR 3.12 (95% CI 1.35-7.74; P=.008) and OR 2.35 (95% CI 1.24-4.45; P=.008), respectively, and post-thrombotic syndrome, OR 3.44 (95% CI 1.43-8.83; P=.005) and OR 2.35 (95% CI 1.24-4.45; P=.008). Our study confirmed the association between dyslipidemia and VTE and showed a risk of thrombosis nearly 4 times higher in individuals with this disease. In addition, alterations in the lipid profile were also related to a higher prevalence of thrombotic complications, recurrence and post-thrombotic syndrome. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  17. Idiopathic versus secondary venous thromboembolism. Findings of the RIETE registry.

    Science.gov (United States)

    Pedrajas, J M; Garmendia, C; Portillo, J; Gabriel, F; Mainez, C; Yera, C; Monreal, M

    2014-10-01

    The Computerized Registry of Patients with Venous Thromboembolism (RIETE) is a prospective registry that consecutively includes patients diagnosed with venous thromboembolism. We compared the clinical presentation and response to anticoagulant treatment in patients with idiopathic venous thromboembolism (IVT) versus secondary venous thromboembolism (SVT, associated with a risk factor). We analyzed the differences in clinical characteristics, comorbidity, treatment and events during the first 3months after the diagnosis of venous thromboembolism in patients with IVT or SVT and according to their initial clinical presentation. A total of 39,921 patients with IVT (n=18,029; 45.1%) or SVT (n=21,892; 54.9%) were enrolled. The patients with IVT had a greater history of venous thromboembolism than those diagnosed with SVT (pSVT group (pSVT group than in the IVT group. At 90days, bleeding, death and the recurrence of venous thromboembolism were significantly more frequent in the SVT group. The multivariate analysis confirmed that IVT was associated with fewer major (OR, 0.60; 95%CI, 0.50-0.61; pSVT at 90days of the diagnosis. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  18. Nurses' knowledge about venous leg ulcer care: a literature review.

    Science.gov (United States)

    Ylönen, M; Stolt, M; Leino-Kilpi, H; Suhonen, R

    2014-06-01

    There is an increasing prevalence of venous leg ulcers coinciding with increasing older people populations. They are therefore important health problems, which restrict daily activities and incur high costs. Efficient and comprehensive nursing care for people with venous leg ulcers requires knowledge of causes, presentations and characteristics, the effects that venous leg ulcers have on individuals and nursing care with evidence-based treatment. To identify the gaps between nurses' demonstrated knowledge of venous leg ulcers and the related nursing care treatment with evidence-based nursing care. A computerized search using MEDLINE, CINAHL the COCHRANE LIBRARY was conducted. The initial search yielded 174 citations from which 16 relevant articles were included in this review. Four themes in venous leg ulcer nursing care emerged demonstrating nurses' knowledge gaps: assessment, physiology and the healing process, nursing care and dressings, and compression treatment. This review suggests that there is a lack of knowledge related to venous leg ulcer physiology, the healing process and how this influences care and treatment. Nurses may not be using the evidence base sufficiently well to support ulcer healing and patient well-being. There is a need for a positive work culture development and ongoing educational programmes aimed at improving nurses' knowledge of venous leg ulcer treatment and care, which address the themes within the results of this review. © 2014 International Council of Nurses.

  19. Hepatic venous pressure gradients measured by duplex ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Tasu, J.-P.; Rocher, L.; Peletier, G.; Kuoch, V.; Kulh, E.; Miquel, A.; Buffet, C.; Biery, M

    2002-08-01

    AIMS: The hepatic venous pressure gradient is a major prognostic factor in portal hypertension but its measurement is complex and requires invasive angiography. This study investigated the relationship between the hepatic venous pressure gradient and a number of Doppler measurements, including the arterial acceleration index. METHOD: We measured the hepatic venous pressure gradient in 50 fasting patients at hepatic venography. Immediately afterwards, a duplex sonographic examination of the liver was performed at which multiple measurements and indices of the venous and arterial hepatic vasculature were made. RESULTS: Hepatic arterial acceleration was correlated directly with the hepatic venous pressure gradient (r = 0.83, P < 0.0001) and with the Child-Pugh score (r = 0.63, P < 0.0001). An acceleration index cut-off value of 1 m.s{sup -2} provided a positive predictive value of 95%, a sensitivity of 65% and a specificity of 95% for detecting patients with severe portal hypertension (hepatic venous pressure gradient > 12 mmHg). A correlation between the hepatic venous pressure gradient and the congestion index of the portal vein velocity (r = 0.45,P = 0.01) and portal vein velocity (r = 0.40,P = 0.044), was also noted. CONCLUSION: Measuring the hepatic arterial acceleration index may help in the non-invasive evaluation of portal hypertension. Tasu, J.-P. et al. (2002)

  20. Unsuspected lower extremity deep venous thrombosis simulating musculoskeletal pathology

    Energy Technology Data Exchange (ETDEWEB)

    Parellada, Antoni J.; Reiter, Sean B.; Glickman, Peter L.; Kloss, Linda A. [Frankford Hospitals, DII - Diagnostic Imaging, Inc., Department of Radiology, Philadelphia, PA (United States); Morrison, William B. [Thomas Jefferson University, Philadelphia, PA (United States); Carrino, John A. [Brigham and Women' s Hospital, Harvard Medical School, Boston, MA (United States); Patel, Pinecca [Frankford Hospitals, Jefferson Health System, Philadelphia, PA (United States)

    2006-09-15

    The purpose of this study was to highlight the critical role that MRI may play in diagnosing unsuspected lower extremity deep venous thrombosis and to stress the importance of scrutinizing MRI studies of the lower extremity showing apparently non-specific muscle edema for any evidence of intramuscular venous thrombosis. The imaging studies of four patients in whom deep venous thrombosis was unsuspected on clinical grounds, and first diagnosed on the basis of MRI findings, were reviewed by two musculoskeletal radiologists in consensus. In all four patients the initial clinical suspicion was within the scope of musculoskeletal injuries (gastrocnemius strain, n=3; ruptured Baker cyst, n=1), explaining the choice of MRI over ultrasound as the first diagnostic modality. All patients showed marked reactive edema in the surrounding soft tissues or muscles. Three patients showed MR evidence of branching rim-enhancing structures within intramuscular plexuses characteristic of venous thrombosis (gastrocnemius, n=1; sural, n=2); one patient showed a distended popliteal vein. Ultrasound was able to duplicate the MRI findings in three patients: one patient showed above-the-knee extension on ultrasound; neither of the two patients with intramuscular thrombosis demonstrated on ultrasound showed extension to the deep venous trunks. Intramuscular venous thrombosis can present as marked edema-like muscle changes on MRI, simulating primary musculoskeletal conditions. In the absence of clinical suspicion for deep venous thrombosis, only the identification of rim-enhancing branching intramuscular tubular structures will allow the correct diagnosis to be made. (orig.)

  1. Intravascular thrombosis as a result of central venous access.

    Science.gov (United States)

    Biernacka, Jadwiga; Nestorowicz, Andrzej; Wach, Małgorzata

    2002-01-01

    Central venous access represents one of the most basic therapeutic procedures in modern medicine. Unfortunately, numerous advantages that result from maintaining a central venous line are accompanied by some complications among which the venous thrombosis is the most significant clinically. The study was designed to assess frequency and natural history of this complication in the setting at a multi profile clinical hospital. Central venous cannulation was performed by a fully qualified anaesthesiologist in every case. There were 887 cannulations and only 5 patients with clinically significant venous thrombosis. The analysis of the collected data allowed us to state that the frequency of intravascular thrombosis is low, but this complication is often associated with extensive impairment of patency of the central veins. Full recanalization is not always achieved regardless of the treatment applied. Pulmonary embolism in the course of central venous thrombosis was diagnosed in one patient only and appeared as a multiple and fine X-ray infiltrates. It seems that in the presence of permanent or even life threatening complications of central venous thrombosis their risk should be minimized by frequent examination of the cannulation site and early initiation of antithrombotic treatment.

  2. Venous Stenosis and Occlusion in the Presence of Endocardial Leads.

    Science.gov (United States)

    Boczar, Krzysztof; Ząbek, Andrzej; Haberka, Kazimierz; Hardzina, Małgorzata; Dębski, Maciej; Rydlewska, Anna; Nowosielska-Ząbek, Ewa; Lelakowski, Jacek; Małecka, Barbara

    2016-01-01

    Venous stenosis and occlusion in the presence of endocardial leads constitute one of the complications of permanent cardiac pacing either by pacemaker, implantable cardioverter-defibrillator or cardiac resynchronization therapy. The aim of this study was to assess the incidence of stenosis and occlusions and determine the risk factors in patients with endocardial leads in a prospective single-center study. Two hundred eighty consecutive patients aged 25-95 years (male 68.8%) were included. A contrast venography examination of the ipsilateral access vein was performed. The whole study population was divided into 2 groups, based on the presence (group I) or absence (group II) of endocardial leads. Venous stenosis/occlusion was identified in 51 patients (37.5%) in group I and in 3 patients (3.6%) in group II; p lead presence most highly correlated with venous complications (OR = 4.172; p leads divided into I A and I B according to venous patency diabetes mellitus was proved in multivariate analysis to be the only protective factor against the development of venous stenosis/occlusion (OR = 0.473; p = 0.010). The presence of endocardial leads is a predisposing factor for venous stenosis/occlusion and increases the risk 4-fold. The venous lesions in the presence of endocardial leads are less frequent among patients with diabetes mellitus.

  3. Regarding optical coherence tomography grading of ischemia in central retinal venous occlusion

    Directory of Open Access Journals (Sweden)

    Tripathy K

    2017-02-01

    Full Text Available Koushik TripathyDepartment of Vitreoretina and Uvea, ICARE Eye Hospital & Postgraduate Institute, Noida, Uttar Pradesh, IndiaThe author read with interest the article by Browning et al.1 The author humbly wants to discuss a few facts.1. The article1 discusses grading of retinal ischemia based on optical coherence tomography features in central retinal venous occlusion. As coexisting central retinal arterial occlusion or cilioretinal arterial occlusion may also cause inner retinal hyper-reflectivity, exclusion of such cases is an important consideration before implicating central retinal venous occlusion for the ischemia. Extensive intraretinal hemorrhages are other important hindrances to the evaluation of the perfusion status of the retina using both fluorescein angiogram and optical coherence tomography.2. It would be interesting to know the gonioscopic findings, especially neovascularization of the anterior chamber angle if it was performed at presentation and during the follow-ups.3. The manuscript documented that the incidence of anterior segment neovascularization at 1 year was 8.9% in severe ischemia group.1 The incidence of anterior segment neovascularization in perfused groups was higher (15.4% and 17.6% for mild and moderate ischemia, respectively. Although the sample size was low, such findings are contrary to the literature2 and require further discussion. Authors' replyDavid J Browning, Omar S Punjabi, Chong LeeDepartment of Ophthalmology, Charlotte Eye, Ear, Nose and Throat Associates, P.A., Charlotte, NC, USA We thank Dr Tripathy for his interest in our article and would respond to his above-mentioned points.1. We agree that excluding eyes with cilioretinal artery and central retinal artery occlusions is necessary to be able to attribute inner retinal reflectivity changes to central retinal vein occlusion. Cilioretinal artery occlusion is associated with a band of ischemic retinal whitening and central retinal artery occlusion

  4. Therapeutic ultrasound for venous leg ulcers.

    Science.gov (United States)

    Cullum, Nicky; Liu, Zhenmi

    2017-05-15

    Venous leg ulcers are a type of chronic, recurring, complex wound that is more common in people aged over 65 years. Venous ulcers pose a significant burden to patients and healthcare systems. While compression therapy (such as bandages or stockings) is an effective first-line treatment, ultrasound may have a role to play in healing venous ulcers. To determine whether venous leg ulcers treated with ultrasound heal more quickly than those not treated with ultrasound. We searched the Cochrane Wounds Specialised Register (searched 19 September 2016); the Cochrane Central Register of Controlled Trials (CENTRAL; the Cochrane Library 2016, Issue 8); Ovid MEDLINE (including In-Process & Other Non-Indexed Citations, MEDLINE Daily and Epub Ahead of Print) (1946 to 19 September 2016); Ovid Embase (1974 to 19 September 2016); and EBSCO CINAHL Plus (1937 to 19 September 2016). We also searched three clinical trials registries and the references of included studies and relevant systematic reviews. There were no restrictions based on language, date of publication or study setting. Randomised controlled trials (RCTs) that compared ultrasound with no ultrasound. Eligible non-ultrasound comparator treatments included usual care, sham ultrasound and alternative leg ulcer treatments. Two authors independently assessed the search results and selected eligible studies. Details from included studies were summarised using a data extraction sheet, and double-checked. We attempted to contact trial authors for missing data. Eleven trials are included in this update; 10 of these we judged to be at an unclear or high risk of bias. The trials were clinically heterogeneous with differences in duration of follow-up, and ultrasound regimens. Nine trials evaluated high frequency ultrasound; seven studies provided data for ulcers healed and two provided data on change in ulcer size only. Two trials evaluated low frequency ultrasound and both reported ulcers healed data.It is uncertain whether high

  5. ENDOVASCULAR TREATMENT FOR DISORDERS OF THE VENOUS SYSTEM

    Directory of Open Access Journals (Sweden)

    A. G. Osiev

    2015-01-01

    Full Text Available The annual rate of deep vein thrombosis in general population is from 5 to 9 cases per 10 000, whereas for venous thromboembolism (deep vein thrombosis and pulmonary embolism taken together amounts to 14 cases per 10 000. To improve longterm results of therapy for thrombosis of deep veins of the lower extremities, it is important to restore venous function and outflow. Anticoagulant therapy with low weight or non-fractionated heparin preparations remains the most widely used method of management. However, total or partial thrombosis resolution under anticoagulant treatment is achieved only in 4 and 14% of cases, respectively. Thrombolysis allows for early resorption of the thrombus by means of a minimally invasive procedure with lower risk of complication. After the venous flow is restored, the aim of treatment is to prevent damage to the venous valves, venous hypertension and repeated thrombosis with development of the post-thrombotic syndrome. Compared to anticoagulation, systemic thrombolysis has the benefit of more rapid clot resorption and less damage to the venous valve. One of its serious limitations is a high bleeding risk related to higher doses of the drug administered through a peripheral vein catheter. Therefore, selective intra-clot administration of thombolytics (direct catheter thrombolysis has been suggested as an alternative. For more effective therapy with the use of lower doses of thrombolytics, the so called pharmaco-mechanical thrombectomy has been developed. Venous stenosis hindering the venous outflow is frequently seen after direct catheter or pharmaco-mechanical thrombolysis. Angioplasty with stent placement is recommended in the cases with residual venous abnormality after successful thrombolysis and thrombectomy. 

  6. Nontraumatic vascular emergencies: imaging and intervention in acute venous occlusion

    Energy Technology Data Exchange (ETDEWEB)

    Haage, Patrick; Schmitz-Rode, Thomas [Department of Diagnostic Radiology, University of Technology Aachen, Pauwelsstrasse 30, 52057 Aachen (Germany); Krings, Timo [Department of Neuroradiology, University of Technology Aachen, Pauwelsstrasse 30, 52057 Aachen (Germany)

    2002-11-01

    Risk factors for acute venous occlusion range from prolonged immobilization to hypercoagulability syndromes, trauma, and malignancy. The aim of this review article is to illustrate the different imaging options for the diagnosis of acute venous occlusion and to assess the value of interventional strategies for venous thrombosis treatment in an emergency setting. First, diagnosis and treatment of the most common form of venous occlusion, at the level of the lower extremities, is presented, followed by pelvic vein and inferior vena cava occlusion, mesenteric venous thrombosis, upper extremity occlusion, acute cerebral vein thrombosis, and finally acute venous occlusion of hemodialysis access. In acute venous occlusion of the lower extremity phlebography is still the reference gold standard. Presently, duplex ultrasound with manual compression is the most sensitive and specific noninvasive test. Limitations of ultrasonography include isolated distal calf vein occlusion, obesity, and patients with lower extremity edema. If sonography is nondiagnostic, venography should be considered. Magnetic resonance venography can differentiate an acute occlusion from chronic thrombus, but because of its high cost and limited availability, it is not yet used for the routine diagnosis of lower extremity venous occlusion only. Regarding interventional treatment, catheter-directed thrombolysis can be applied to dissolve thrombus in charily selected patients with symptomatic occlusion and no contraindications to therapy. Acute occlusion of the pelvic veins and the inferior vena cava, often due to extension from the femoropopliteal system, represents a major risk for pulmonary embolism. Color flow Doppler imaging is often limited owing to obesity and bowel gas. Venography has long been considered the gold standard for identifying proximal venous occlusion. Both CT scanning and MR imaging, however, can even more accurately diagnose acute pelvis vein or inferior vena cava occlusion. MRI is

  7. Acute Mesenteric Venous Thrombosis with a Vaginal Contraceptive Ring

    Directory of Open Access Journals (Sweden)

    Wesley Eilbert

    2014-07-01

    Full Text Available Mesenteric venous thrombosis is a rare cause of abdominal pain, which if left untreated may result in bowel infarction, peritonitis and death. The majority of patients with this illness have a recognizable, predisposing prothrombotic condition. Oral contraceptives have been identified as a predisposing factor for mesenteric venous thrombosis in reproductive-aged women. In the last fifteen years new methods of hormonal birth control have been introduced, including a transdermal patch and an intravaginal ring. In this report, we describe a case of mesenteric venous thrombosis in a young woman caused by a vaginal contraceptive ring. [West J Emerg Med. 2014;15(4:395-397.

  8. Role of sodium tetradecyl sulfate in venous malformations

    Directory of Open Access Journals (Sweden)

    Saraf Sanjay

    2006-01-01

    Full Text Available Venous malformations are one of the commonest anomalies of the vascular tree and their management has always remained a major challenge. Surgery and other treatment modalities are not always satisfactory and have a higher morbidity, recurrence and complication rate. The author retrospectively analyzed 40 patients of venous malformations who underwent sclerotherapy with sodium tetradecyl sulfate solely or as an adjunct to surgery. The purpose of the study was to evaluate the efficacy and safety of sodium tetradecyl sulfate sclerotherapy in the treatment of venous malformations.

  9. Imaging of the complications of peripherally inserted central venous catheters

    Energy Technology Data Exchange (ETDEWEB)

    Amerasekera, S.S.H. [Department of Radiology, Good Hope Hospital, Sutton Coldfield, Birmingham (United Kingdom)], E-mail: steve.amerasekera@nhs.net; Jones, C.M.; Patel, R.; Cleasby, M.J. [Department of Radiology, Good Hope Hospital, Sutton Coldfield, Birmingham (United Kingdom)

    2009-08-15

    Peripherally inserted central catheters (PICC) are widely used to provide central venous access, often in chronically ill patients with long-term intravenous access requirements. There are a number of significant complications related to both insertion and maintenance of PICC lines, including catheter malposition, migration, venous thrombosis, and line fracture. The incidence of these complications is likely to rise as the number of patients undergoing intravenous outpatient therapy increases, with a corresponding rise in radiologist input. This paper provides an overview of the relevant peripheral and central venous anatomy, including anatomical variations, and outlines the complications of PICC lines. Imaging examples demonstrate the range of radiological findings seen in these complications.

  10. Venous anomalies as potentially lethal risk factors during ordinary catheterization

    Directory of Open Access Journals (Sweden)

    Savino Occhionorelli

    2015-06-01

    Full Text Available Venous malformations are rare but possible findings too, constituting a further risk factor for central venous catheter procedures. Herein we describe a case of death because of an innominate vein perforation by a catheter that incidentally was tucked into a sacciform malformation. Even if the technology advancement is constantly offering us new investigation tools, up to now diagnostic options are limited in the detection of those malformations that could potentially lead to dramatic complications as the described one. The present work raises the awareness about rare venous anomalies and their potential clinical implications. A proper literature review and diagnostic implementation proposal are reported.

  11. Extensive portal venous gas: Unlikely etiology and outcome

    Directory of Open Access Journals (Sweden)

    Tiffany P. Schatz

    2015-01-01

    Full Text Available Portal venous gas or hepatic portal venous gas (HPVG found on imaging portends grave outcomes for patients suffering from ischemic bowel disease or mesenteric ischemia. HPVG is more rarely seen with severe but treatable abdominal infection as well as multiple benign conditions, and therefore must be aggressively evaluated. We report a 70-year old female who developed extensive intra- and extra-hepatic portal venous gas, pneumatosis intestinalis and free air associated with a perforation of the jejunojejunostomy after a gastrectomy for gastric carcinoma.

  12. Management of mixed arterial venous lower extremity ulceration: A review.

    Science.gov (United States)

    Hedayati, Nasim; Carson, John G; Chi, Yung-Wei; Link, Daniel

    2015-10-01

    Mixed arterial venous disease is estimated to affect up to 26% of patients with lower extremity ulcerations. However, its clinical significance and pathophysiology are incompletely understood. Furthermore, there is no consensus on the optimal treatment modality, whether conservative or operative. In this review paper, we describe the current understanding of the pathophysiology of mixed arterial venous lower extremity ulcers. Guidelines for diagnostic tests for patients with mixed arterial venous diseases are discussed. We review some of the newer biological skin substitutes for conservative wound care. Finally, we propose a treatment algorithm based on current available data. © The Author(s) 2015.

  13. Traumatic dural venous sinus thrombosis: A Mini Review

    Directory of Open Access Journals (Sweden)

    Moscote-Salazar Luis Rafael

    2016-09-01

    Full Text Available The dural venous sinus thrombosis is a benign disease, representing about 1% of cerebral vascular events. In some cases the development of the disease increased intracranial pressure or symptomatic epilepsy. The development towards a dural venous sinus thrombosis is rare, but is a condition to be considered before the development of ischemic vascular events and a history of recent head trauma. Intracranial hematomas or skull fractures can lead to the establishment of obstructive pathology of the dural venous sinuses. The knowledge of this entity is necessary for the critical care staff and neurosurgery staff.

  14. BILATERAL INTRAOCULAR HEMORRHAGE SECONDARY TO CEREBRAL VENOUS SINUS THROMBOSIS.

    Science.gov (United States)

    Kunle-Hassan, Feyi; Dattani, Minaxi; Snead, Martin; Subash, Mala

    2016-10-05

    To report a case of bilateral intraocular hemorrhage secondary to cerebral venous sinus thrombosis with no associated intracranial hemorrhage. Case report. A 32-year-old Asian gentleman presented with left reduced vision as a result of a left subhyaloid macular hemorrhage associated with severe headache. Right retinal hemorrhages were also present. Magnetic resonance imaging and computed tomography brain imaging demonstrated cerebral transverse venous sinus thrombosis. Intraocular hemorrhage has previously been described in association with intracranial hemorrhage and in particular subarachnoid hemorrhage (Terson syndrome). We describe a similar clinical picture in the context of cerebral venous sinus thrombosis with no associated intracranial hemorrhage.

  15. Acceptable results after venous reconstructive surgery following iatrogenic injuries to the iliofemoral vein segment

    DEFF Research Database (Denmark)

    Larsen, Morten Bo; Bækgaard, Niels

    2012-01-01

    Venous reconstructions after iatrogenic injuries are rarely performed and are associated with a relatively high risk of complications. We present our experiences with venous reconstructive surgery to the iliofemoral vein segment.......Venous reconstructions after iatrogenic injuries are rarely performed and are associated with a relatively high risk of complications. We present our experiences with venous reconstructive surgery to the iliofemoral vein segment....

  16. A comparison of the biomechanical effects of valgus knee braces and lateral wedged insoles in patients with knee osteoarthritis.

    Science.gov (United States)

    Jones, Richard K; Nester, Christopher J; Richards, Jim D; Kim, Winston Y; Johnson, David S; Jari, Sanjiv; Laxton, Philip; Tyson, Sarah F

    2013-03-01

    Increases in the external knee adduction moment (EKAM) have been associated with increased mechanical load at the knee and progression of knee osteoarthritis. Valgus knee braces and lateral wedged insoles are common approaches to reducing this loading; however no study has directly compared the biomechanical and clinical effects of these two treatments in patients with medial tibiofemoral osteoarthritis. A cross-over randomised design was used where each intervention was worn by 28 patients for a two week period. Pre- and post-intervention gait kinematic/kinetic data and clinical outcomes were collected to evaluate the biomechanical and clinical effects on the knee joint. The valgus knee brace and the lateral wedged insole significantly increased walking speed, reduced the early stance EKAM by 7% and 12%, and the knee adduction angular impulse by 8.6 and 16.1% respectively. The lateral wedged insole significantly reduced the early stance EKAM compared to the valgus knee brace (p=0.001). The valgus knee brace significantly reduced the knee varus angle compared to the baseline and lateral wedged insole. Improvements in pain and function subscales were comparable for the valgus knee brace and lateral wedged insole. There were no significant differences between the two treatments in any of the clinical outcomes; however the lateral wedged insoles demonstrated greater levels of acceptance by patients. This is the first study to biomechanically compare these two treatments, and demonstrates that given the potential role of knee loading in osteoarthritis progression, that both treatments reduce this but lateral wedge insoles appear to have a greater effect. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Saltwater wedge variation in a non-anthropogenic coastal karst aquifer influenced by a strong tidal range (Burren, Ireland)

    Science.gov (United States)

    Perriquet, Marie; Leonardi, Véronique; Henry, Tiernan; Jourde, Hervé

    2014-11-01

    Spatial and temporal changes in saltwater wedges in coastal karst aquifers are still poorly understood, largely due to complex mixing processes in these heterogeneous environments, but also due to anthropogenic forcing such as pumping, which commonly affect natural variations in wedges. The purpose of this study was first to characterize the hydrodynamic functioning of a karst aquifer in an oceanic temperate climate with little anthropogenic pressure but strongly influenced by a high tidal range and second, to evaluate the extent and movements of a saltwater wedge influenced by both the tide and the natural recharge of the aquifer. Variations in specific conductivity combined with water chemistry results from six boreholes and two lakes located in the Bell Harbour catchment (western Ireland) enabled us to assess the extent of the intrusion of the saltwater wedge into the aquifer as a function of both karst recharge and tidal movements at high/low and neap/spring tidal cycles. The marked spatial disparity of the saltwater wedge was analysed as a function of both the hydrodynamic and the structural properties of the karst aquifer. Results showed that the extent of the saltwater wedge depended not only on the intrinsic properties of the aquifer but also on the relative influence of the recharge and the tide on groundwater levels, which have opposite effects. Recharge in the Burren area throughout the year is large enough to prevent saltwater intruding more than about one kilometre from the shore. A strong tidal amplitude seems to be the motor of sudden saltwater intrusion observed in the aquifer near the shore while the position of the groundwater level seems to influence the intensity of the salinity increase. Competition between recharge and the tide thus controls the seawater inputs, hence explaining temporal and spatial changes in the saltwater wedge in this coastal karst aquifer.

  18. Assessing strain mapping by electron backscatter diffraction and confocal Raman microscopy using wedge-indented Si

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, Lawrence H.; Vaudin, Mark D.; Stranick, Stephan J.; Stan, Gheorghe; Gerbig, Yvonne B.; Osborn, William; Cook, Robert F., E-mail: robert.cook@nist.gov

    2016-04-15

    The accuracy of electron backscatter diffraction (EBSD) and confocal Raman microscopy (CRM) for small-scale strain mapping are assessed using the multi-axial strain field surrounding a wedge indentation in Si as a test vehicle. The strain field is modeled using finite element analysis (FEA) that is adapted to the near-indentation surface profile measured by atomic force microscopy (AFM). The assessment consists of (1) direct experimental comparisons of strain and deformation and (2) comparisons in which the modeled strain field is used as an intermediate step. Direct experimental methods (1) consist of comparisons of surface elevation and gradient measured by AFM and EBSD and of Raman shifts measured and predicted by CRM and EBSD, respectively. Comparisons that utilize the combined FEA–AFM model (2) consist of predictions of distortion, strain, and rotation for comparison with EBSD measurements and predictions of Raman shift for comparison with CRM measurements. For both EBSD and CRM, convolution of measurements in depth-varying strain fields is considered. The interconnected comparisons suggest that EBSD was able to provide an accurate assessment of the wedge indentation deformation field to within the precision of the measurements, approximately 2×10{sup −4} in strain. CRM was similarly precise, but was limited in accuracy to several times this value. - Highlights: • We map strain by electron backscatter diffraction and confocal Raman microscopy. • The test vehicle is the multi-axial strain field of wedge-indented silicon. • Strain accuracy is assessed by direct experimental intercomparison. • Accuracy is also assessed by atomic force microscopy and finite element analyses. • Electron diffraction measurements are accurate; Raman measurements need refinement.

  19. Experiments on melt-rock reaction in the shallow mantle wedge

    Science.gov (United States)

    Mitchell, Alexandra L.; Grove, Timothy L.

    2016-12-01

    This experimental study simulates the interaction of hotter, deeper hydrous mantle melts with shallower, cooler depleted mantle, a process that is expected to occur in the upper part of the mantle wedge. Hydrous reaction experiments ( 6 wt% H2O in the melt) were conducted on three different ratios of a 1.6 GPa mantle melt and an overlying 1.2 GPa harzburgite from 1060 to 1260 °C. Reaction coefficients were calculated for each experiment to determine the effect of temperature and starting bulk composition on final melt compositions and crystallizing assemblages. The experiments used to construct the melt-wall rock model closely approached equilibrium and experienced crystallizing assemblages are dunites, harzburgites, and lherzolites (as a function of temperature). When the ratio of deeper melt to overlying mantle is 70:30, the crystallizing assemblage is a wehrlite. This shows that wehrlites, which are observed in ophiolites and mantle xenoliths, can be formed by large amounts of deeper melt fluxing though the mantle wedge during ascent. In all cases, orthopyroxene dissolves in the melt, and olivine crystallizes along with pyroxenes and spinel. The amount of reaction between deeper melts and overlying mantle, simulated here by the three starting compositions, imposes a strong influence on final melt compositions, particularly in terms of depletion. At the lowest melt/mantle ratios, the resulting melt is an extremely depleted Al-poor, high-Si andesite. As the fraction of melt to mantle increases, final melts resemble primitive basaltic andesites found in arcs globally. An important element ratio in mantle lherzolite composition, the Ca/Al ratio, can be significantly elevated through shallow mantle melt-wall rock reaction. Wall rock temperature is a key variable; over a span of lherzolite. Together, the experimental phase equilibria, melt compositions, and reaction coefficients provide a framework for understanding how melt-wall rock reaction occurs in the natural

  20. The Seismic Structure of the Mantle Wedge under Cascade Volcanoes, Northwestern U.S.A.

    Science.gov (United States)

    Levander, A.; Liu, K.; Porritt, R.; Allen, R.; Yang, Y.

    2012-04-01

    For corner flow models to be correct, the mantle wedge of a subduction zone must have an unusual lithosphere-asthenosphere boundary, as the reduced viscosities from slab dewatering, melting, and relatively hot return flow must move the lithosphere-asthenosphere boundary close to the base of the crust of the overriding plate. This should be detectable with several different seismic probes. Under a number of the volcanoes of the Cascadia arc we have identified a characteristic seismic signature in individual station Ps receiver functions and in Ps CCP image volumes made from USArray Transportable Array and Flexible Array stations. In the mantle wedge, the CCP images and the RFs show a strong negative event just below the Moho, paired with a weak to moderate positive event between 50-70 km, and a strong slab event. At most of these volcanoes, a strong negative signal also appears between 15 and 25 km depth in the crust. The signature is particularly clear under Mt. Lassen and to a lesser degree under Mt. Shasta in data from FAME (Flexible Array Mendocino Experiment), where instruments were close to the volcanic centers. Random averages using all stations throughout the western U.S., and only stations in the Cascadia backarc region show that this signature is not common to the western U.S. as a whole, nor to the backarc region in particular. Joint inversion of the Ps receiver functions and ambient noise and ballistic Rayleigh wave phase velocities (Porritt et al., 2011; Liu et al., 2012) for those volcanoes with the paired events provides 1D shear velocity profiles having common characteristics. A strong sub-Moho low velocity zone from 5 to 15 km thick gives rise to the paired negative-positive signals in the receiver functions. These mantle wedge low velocity zones, with velocities of 3.7 CIDER 2011 summer program.

  1. The Superimposed Paleocene-Miocene Tectonics of the middle part of the Nallihan Wedge (NW Turkey)

    Science.gov (United States)

    Şahin, Murat; Yaltirak, Cenk

    2015-04-01

    In the NW Turkey, the area between the suture zones of the Rhodope-Pontide Ocean and Izmir-Ankara Ocean, and North Anatolian Fault Zone (NAFZ) and Thrace-Eskişehir Fault Zone (TEFZ) is known as the Nallıhan Wedge. The shape of Nallıhan Wedge is a 90 degree counter-clockwise rotated isosceles triangle. The northwestern boundary is a part of NAFZ and the southwestern boundary is a part of TEFZ. The 160 km-long eastern boundary is located at around Beypazarı and western corner is on the Bursa Plain. Nallıhan is situated at the centre of this isosceles triangle. While all the thrusts and folds shrink towards to the west and show an imbricate-like structure, the characteristics of the folds turn into to the open folds. Thrusts faults are locally observed as blind and almost perpendicular thrusts at the fold limbs towards to the east. The rocks of the study area show different characteristics according to their types and basins of formation. On the other hand the structural properties of these rocks display the effects of the closure of the Intra-Pontide and Izmir-Ankara Oceans in between Paleocene and Early Oligocene. During Miocene, the thrust faults reactivated and a deformation formed the NEE-SWW left lateral strike-slip faults parallel to these thrust faults. Whereas the first events are related to the closure of the branches of Neo-Tethys, the Miocene deformation is probably based on the Miocene tectonics of the Western Anatolia by the reason of equivalent age of the TEFZ. In this framework, the deformation of the Nallıhan Wedge presents significant information about the period between the evolution of Paleotectonic and Neotectonic of Turkey.

  2. Lung-conserving treatment of a pulmonary oligometastasis with a wedge resection and 131Cs brachytherapy.

    Science.gov (United States)

    Wernicke, A Gabriella; Parikh, Apurva; Yondorf, Menachem; Trichter, Samuel; Gupta, Divya; Port, Jeffrey; Parashar, Bhupesh

    2013-01-01

    Soft-tissue sarcomas most frequently metastasize to the lung. Surgical resection of pulmonary metastases is the primary treatment modality. Although lobectomy is widely acknowledged as the standard procedure to treat primary pulmonary tumors, the standard for pulmonary metastases is not well defined; furthermore, compromised lung function may tip the scales in favor of a less invasive approach. Here, we report the results of a patient treated with wedge resection and intraoperative cesium-131 ((131)Cs). A 58-year-old African American female was diagnosed with the American Joint Committee on Cancer Stage IIA mixed uterine leiomyosarcoma and underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy followed by adjuvant external beam radiotherapy to a total dose of 45 Gy and vaginal brachytherapy to a total dose of 20 Gy. At 2 years, a routine CT scan of the chest revealed metastasis to right upper lobe of the lung. The patient's poor pulmonary function, related to a 45 pack-year smoking history and chronic emphysema, precluded a lobectomy. After the patient underwent a lung-sparing wedge resection of the pulmonary right upper lobe metastasis and intraoperative brachytherapy with (131)Cs seeds to a total dose of 80 Gy, she remained disease free in the implanted area. At a 2-year followup, imaging continued to reveal 100% local control of the area treated with wedge resection and intraoperative (131)Cs brachytherapy. The patient had no complications from this treatment. Such treatment approach may become an attractive option in patients with oligometastatic disease and compromised pulmonary function. Copyright © 2013 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  3. Hypoplasia of L5 and wedging and pseudospondylolisthesis in patients with spondylolysis: study with MR imaging.

    Science.gov (United States)

    Wilms, G; Maldague, B; Parizel, P; Meylaerts, L; Vanneste, D; Peluso, J

    2009-04-01

    The association between L5 hypoplasia and bilateral spondylolysis was described earlier on conventional radiographs of the lumbar spine. The purpose of this study was to describe the findings on MR imaging in patients with hypoplasia of L5 and to correlate these findings with the presence of bilateral spondylolysis of L5. We studied the MR images of 22 patients with hypoplasia and posterior wedging of L5 and with bilateral spondylolysis at L5. The anteroposterior diameter of L4, L5, and S1 were measured and compared. The degree of posterior wedging of L5 was calculated. The degree of anterolisthesis was determined. The intervertebral disks of L4-L5 and L5-S1 were studied. The mean difference between the anteroposterior diameter of L4 and L5 was 3.0 mm, or 8.8% shortening of L5 compared with L4. The mean difference between the anteroposterior diameter of L5 and S1 was 4.4 mm, or 12.3% shortening of L5 compared with S1. The mean percentage posterior wedging was 24.7%. In 13 patients, there was no anterior vertebral slipping. True anterolisthesis grade I was seen in 5 patients and anterolisthesis grade II in 4 patients. Diskarthrosis with disk dehydration of L4-L5 was seen in 20 of the 22 patients. It is confirmed that hypoplasia of L5 can simulate anterolisthesis. Hypoplasia of the vertebral body of L5 can predict the presence of bilateral spondylolysis.

  4. The results of high tibial open wedge osteotomy in patients with varus deformity

    Directory of Open Access Journals (Sweden)

    Mahmood Jabalameli

    2013-07-01

    Full Text Available Background: High tibial open wedg osteotomy is one of the most important modality for treatment of varus deformity in order to correct deformity and improving signs and symptoms of patients with primary degenerative osteoarthritis. The aim of this study was to investigate the results of high tibial open wedge osteotomy in patients with varus deformities.Methods: This retrospective study conducted on twenty nine patients (36 knees undergone proximal tibial osteotomy operation in Shafa Yahyaian University Hospital from 2004 to 2010. Inclusion criteria were: age less than 60 years, high physical activity, varus deformity and involvement of medical compartment of knee. Patients with obesity, smoking, patelofemoral pain, lateral compartment lesion, deformity degree more than 20 degree, extension limitation and range of motion less than 90 degree were excluded. The clinical and radiologic characteristics were measured before and after operation.Results: Fourteen patients were females. All of them were younger than 50 years, with mean (±SD 27.64 (±10.88. The mean (±SD of follow up time was 4.33 (±1.7. All the patients were satisfied with the results of operation. Tenderness and pain decreased in all of them. In all patients autologus bone graft were used, in 15 cases (42.5% casting and in the rest T.Buttress plate were used for fixation of fractures. In both groups of primary and double varus the International knee documentation committee (IKDC and modified Larson indices were improved after operation, but there was no significant difference between two groups.Conclusion: High tibial open wedge osteotomy can have satisfying results in clinical signs and symptoms of patients with primary medial joint degenerative osteoarthritis. This procedure also may correct the deformity and improves the radiologic parameters of the patients.

  5. Cardiac arrhythmias associated with umbilical venous catheterisation in neonates

    Science.gov (United States)

    Verheij, Gerdina; Smits-Wintjens, Vivianne; Rozendaal, Lieke; Blom, Nico; Walther, Frans; Lopriore, Enrico

    2009-01-01

    Umbilical venous catheters (UVCs) are commonly used in the management of severely ill neonates. Several life-threatening complications have been described, including catheter-related infections, myocardial perforation, pericardial effusion and cardiac arrhythmias. This report describe two neonates with cardiac arrhythmias due to umbilical venous catheterisation. One neonate had a supraventricular tachycardia requiring treatment with intravenous adenosine administration. Another neonate had an atrial flutter and was managed successfully with synchronised cardioversion. The primary cause of cardiac arrhythmias after umbilical venous catheterisation is inappropriate position of the UVC within the heart and the first step to treat them should be to pull back or even remove the catheter. Cardiac arrhythmia is a rare but potentially severe complication of umbilical venous catheterisation in neonates. PMID:21691401

  6. The pathogenesis of venous thromboembolism : Evidence for multiple interrelated causes

    NARCIS (Netherlands)

    Brouwer, Jan-Leendert P.; Veeger, Nic J. G. M.; Kluin-Nelemans, Hanneke C.; van der Meer, Jan

    2006-01-01

    Background: Venous thromboembolism (VTE) is thought to result from interactions between multiple genetic and environmental risk factors. Objective: To assess the contribution of multiple thrombophilic defects and exogenous risk factors to the absolute risk for VTE. Design: Retrospective family

  7. Splanchnic venous thrombosis driven by a constitutively activated ...

    African Journals Online (AJOL)

    Introduction: Splanchnic venous thrombosis (SVT) has varied etiology with Philadelphia-negative myeloproliferative neoplasms (MPNs) being the most frequent underlying prothrombotic factor. Hematological indices often remain within normal range because of portal hypertension and its sequelae, causing diagnostic ...

  8. Splanchnic venous thrombosis driven by a constitutively activated ...

    African Journals Online (AJOL)

    Abstract. Introduction: Splanchnic venous thrombosis (SVT) has varied etiology with Philadelphia- negative myeloproliferative neoplasms (MPNs) being the most frequent underlying prothrombotic factor. Hematological indices often remain within normal range because of portal hypertension and its sequelae, causing ...

  9. The where, what and how of paediatric central venous access

    African Journals Online (AJOL)

    2012-04-17

    Apr 17, 2012 ... disturbances or congenital heart disease, these may be sustained. Electrolyte ... Specialist Anaesthetist, Red Cross Children's Hospital, University of Cape Town ... Keywords: central venous catheter, children, acute complications, infection, thrombosis, subclavian vein, femoral vein, internal jugular vein.

  10. Delivery of Compression Therapy for Venous Leg Ulcers

    DEFF Research Database (Denmark)

    Zarchi, Kian; Jemec, Gregor B E

    2014-01-01

    IMPORTANCE: Despite the documented effect of compression therapy in clinical studies and its widespread prescription, treatment of venous leg ulcers is often prolonged and recurrence rates high. Data on provided compression therapy are limited. OBJECTIVE: To assess whether home care nurses achieve...... adequate subbandage pressure when treating patients with venous leg ulcers and the factors that predict the ability to achieve optimal pressure. DESIGN, SETTING, AND PARTICIPANTS: We performed a cross-sectional study from March 1, 2011, through March 31, 2012, in home care centers in 2 Danish...... with venous leg ulcers do not receive adequate compression therapy. Training programs that focus on practical bandaging skills should be implemented to improve management of venous leg ulcers....

  11. [Venous thrombosis of atypical location in patients with cancer].

    Science.gov (United States)

    Campos Balea, Begoña; Sáenz de Miera Rodríguez, Andrea; Antolín Novoa, Silvia; Quindós Varela, María; Barón Duarte, Francisco; López López, Rafael

    2015-01-01

    Venous thromboembolism (VTE) is a complication that frequently occurs in patients with neoplastic diseases. Several models have therefore been developed to identify patient subgroups diagnosed with cancer who are at increased risk of developing VTE. The most common forms of thromboembolic episodes are deep vein thrombosis in the lower limbs and pulmonary thromboembolism. However, venous thrombosis is also diagnosed in atypical locations. There are few revisions of unusual cases of venous thrombosis. In most cases, VTE occurs in the upper limbs and in the presence of central venous catheters, pacemakers and defibrillators. We present the case of a patient diagnosed with breast cancer and treated with surgery, chemotherapy and radiation therapy who developed a thrombosis in the upper limbs (brachial and axillary). Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

  12. Continuous central venous saturation monitoring in pediatrics: a case report.

    Science.gov (United States)

    Spenceley, Neil; Skippen, Peter; Krahn, Gordon; Kissoon, Niranjan

    2008-03-01

    To report the use of a new pediatric central venous catheter that offers continuous central venous saturation (ScVO2) monitoring in the critically ill child. Case report. Pediatric intensive care unit in a tertiary care children's hospital. A 3-month-old child, following cardiac surgery, with an isolated decrease in central venous saturations. Diagnosis of pericardial effusion by echocardiography followed by surgical drainage. ScVO2 readings quickly returned to normal, and the remaining patient course was uneventful. We report the first case of a newly modified central venous catheter (PediaSat Oximetry Catheter, Edwards Lifesciences LLC, Irvine, CA) for children and demonstrate its utility in a patient with impaired oxygen delivery when traditional markers remain stable. This catheter enabled the rapid diagnosis of cardiac compromise due to pericardial effusion, leading to early treatment. Traditional central catheter functions and insertion technique are maintained, making the catheter potentially useful in any critically ill child.

  13. Optical Dating Studies of southeastern Patagonian Sand Wedges in Chile and Argentina

    OpenAIRE

    Cullen, Justine Rose

    2016-01-01

    The purpose of this study was to establish a suitable single aliquot regenerative dose (SAR) optical dating protocol for K-feldspar sediments in southeast Patagonia using radiocarbon-dated Holocene dune sediments at Lago Arturo. The established protocol was then applied to sand wedge sediments found in the region in order to date periods of permafrost and to provide limiting ages on glaciation. The suitable SAR protocol incorporates a 200oC/10 s preheat for both the additive-dose and test dos...

  14. Tunable-angle wedge transducer for improved acoustophoretic control in a microfluidic chip

    DEFF Research Database (Denmark)

    Iranmanesh, I.; Barnkob, Rune; Bruus, Henrik

    2012-01-01

    We present a tunable-angle wedge ultrasound transducer for improved control of microparticle acoustophoresis in a microfluidic chip. The transducer is investigated by analyzing the pattern of aligned particles and induced acoustic energy density while varying the system geometry, transducer......-angle transducer are compared with the results from actuation by a standard planar transducer in order to decouple the influence from change in coupling angle and change in system geometry. We find in this work that the transducer coupling angle is the more important parameter compared to the concomitant change...

  15. Wedge Absorbers for Final Cooling for a High-Energy High-Luminosity Lepton Collider

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, David [Fermilab; Mohayai, Tanaz [IIT, Chicago (main); Snopok, Pavel [IIT, Chicago; Summers, Don [Mississippi U.

    2016-06-01

    A high-energy high-luminosity muon collider scenario requires a "final cooling" system that reduces transverse emittance to ~25 microns (normalized) while allowing longitudinal emittance increase. Ionization cooling using high-field solenoids (or Li Lens) can reduce transverse emittances to ~100 microns in readily achievable configurations, confirmed by simulation. Passing these muon beams at ~100 MeV/c through cm-sized diamond wedges can reduce transverse emittances to ~25 microns, while increasing longitudinal emittance by a factor of ~5. Implementation will require optical matching of the exiting beam into downstream acceleration systems.

  16. Wedge Splitting Test on Fracture Behaviour of Fiber Reinforced and Regular High Performance Concretes

    DEFF Research Database (Denmark)

    Hodicky, Kamil; Hulin, Thomas; Schmidt, Jacob Wittrup

    2013-01-01

    The fracture behaviour of three fiber reinforced and regular High Performance Concretes (HPC) is presented in this paper. Two mixes are based on optimization of HPC whereas the third mix was a commercial mix developed by CONTEC ApS (Denmark). The wedge splitting test setup with 48 cubical specimens...... parameters such as crack opening displacement (COD), fracture energy and characteristic length were experimentally determined. Experiments were performed at 1, 3, 7 and 28 days. Fracture energy, Gf, was found to increasing with age, while the characteristic length, Lch, was found to decrease....

  17. Single-port video-assisted thoracoscopic wedge resection: novel approaches in different genders.

    Science.gov (United States)

    Xu, Kai; Bian, Wen; Xie, Hongya; Ma, Haitao; Ni, Bin

    2016-08-01

    To discuss the feasibility, safety and superiority of novel approaches in single-port video-assisted thoracoscopic wedge resection in different genders. The clinical data of patients who underwent thoracoscopic pulmonary wedge resection were analysed. A total of 197 consecutive male patients from January 2012 to December 2014, and 72 female patients from June 2013 to December 2014 were included retrospectively. Of the males, 65 received a transareolar single-port procedure (TASP Group) and 132 received a standard two-port procedure (Standard Group A). Among the females, 18 were treated with a subxiphoid single-port procedure (SXSP Group), and 54 were treated with the standard procedure (Standard Group B). The general clinical materials and surgical outcomes were evaluated. All patients underwent total thoracoscopic wedge resection successfully, and no severe complications were observed. In men, there were no significant differences in operation time, blood loss, postoperative drainage amount, chest drainage duration, postoperative hospital stay or pain score on the first postoperative day (P = 0.827; 0.423; 0.174; 0.440; 0.115; 0.159, respectively). The pain scores of the TASP Group on the day before and after removal of the chest tube were lower (P = 0.006; 0.023, respectively) than those of Standard Group A, and the incision-associated paraesthesia in the third and sixth month after operation was reduced (P = 0.041; 0.026, respectively). The incision satisfaction degree was significantly improved in the TASP Group (P = 0.001). In women, there were no significant differences in blood loss, drainage amount, chest drainage duration or postoperative hospital stay (P = 0.680; 0.757; 0.651; 0.608, respectively). The operation time of the SXSP Group was longer (P = 0.000), and the pain scores on the first postoperative day and the days before and after removal were all significantly lower (P = 0.000; 0.000; 0.000, respectively) than those of the Standard Group B

  18. Wedge-Local Fields in Integrable Models with Bound States II: Diagonal S-Matrix

    Science.gov (United States)

    Cadamuro, Daniela; Tanimoto, Yoh

    2017-01-01

    We construct candidates for observables in wedge-shaped regions for a class of 1+1-dimensional integrable quantum field theories with bound states whose S-matrix is diagonal, by extending our previous methods for scalar S-matrices. Examples include the Z(N)-Ising models, the A_N-affine Toda field theories and some S-matrices with CDD factors. We show that these candidate operators which are associated with elementary particles commute weakly on a dense domain. For the models with two species of particles, we can take a larger domain of weak commutativity and give an argument for the Reeh-Schlieder property.

  19. Diffraction of an inhomogeneous plane wave by an impedance wedge in a lossy medium

    CSIR Research Space (South Africa)

    Manara, G

    1998-11-01

    Full Text Available in [1] to obtain numerically the three-dimensional (3-D) dyadic diffrac- tion coefficients for right-angle perfect electrical conductor (PEC) wedges. This method exploits the temporal causality inherent in finite- difference time-domain (FDTD) modeling... systematic study of AWE order versus the angular band of the approximation. We observed that if one expansion point is chosen for every angular sector containing a single pattern lobe/null, a Pad` approximation with 76 6149 , 77 6149 ,or77 6148 results in a...

  20. Capillary Pressure in a Wedge-Shaped Channel from Pore-Scale Imaging

    Science.gov (United States)

    Liu, Y.; Pyrak-Nolte, L. J.; Nolte, D. D.; Giordano, N. J.

    2008-12-01

    Our previous experimental investigations of capillary pressure in two-dimensional porous structures observed that, just prior to breakthrough, a deviation occurs between the externally measured capillary pressure and the capillary pressure measured from interfacial curvature. To explore this deviation, we used laser confocal microscopy to image the three-dimensional fluid distribution of two immiscible fluids in a simple wedge-shaped channel to determine whether this deviation occurs from the hidden curvature or the presence of thin films. The wedge-shaped channel was fabricated using two different approaches: two-photon polymerization and broad-illumination photolithography. Both techniques use UV-sensitive photoresist (SU-8) to construct a wedge-shaped micromodel containing a channel that is 100 microns wide at the inlet and 20 microns wide at the outlet with a constant channel depth of 40 microns. A Zeiss LSM 510 Laser Scanning Confocal Microscope was used to image the air and water distributions within the micromodel. Initially, the micromodel was saturated withwater containing Alex Fluor-488 or FITC solution by 1%wt. In these experiments, water is the wetting phase and air is the non-wetting phase. A series of drainage and imbibition cycles were performed by incrementing or decrementing the air pressure appropriately. For each increment in pressure, the system was allowed to equilibrate and then a z-stack scan of the fluid distribution was collected with the confocal microscope. The confocal images were analyzed to extract the volume saturation of air and water, the curvature of the three-dimensional fluid-air interface, and the interfacial area per volume. We observed a hysteretic relationship between capillary pressure and wetting phase saturation for the wedge-shaped channel. An analysis of the capillary pressure from interfacial curvature found that initially the calculated and measured values of capillary pressure were equal. However, as breakthrough was