Sample records for surgical mesh

  1. Hernia Surgical Mesh Implants (United States)

    ... knitted mesh or non-knitted sheet forms. The synthetic materials used can be absorbable, non-absorbable or a combination of absorbable and non-absorbable materials. Animal-derived mesh are made of animal tissue, such as intestine or skin, that has been processed and disinfected to be ...

  2. Urogynecologic Surgical Mesh Implants (United States)

    ... knitted mesh or non-knitted sheet forms. The synthetic materials used can be either absorbable, non-absorbable, or a combination of absorbable and non-absorbable materials. Animal-derived mesh are made of animal tissue, such as intestine or skin, that have been processed and disinfected to be ...

  3. Surgical management of lower urinary mesh perforation after mid-urethral polypropylene mesh sling: mesh excision, urinary tract reconstruction and concomitant pubovaginal sling with autologous rectus fascia. (United States)

    Shah, Ketul; Nikolavsky, Dmitriy; Gilsdorf, Daniel; Flynn, Brian J


    We present our management of lower urinary tract (LUT) mesh perforation after mid-urethral polypropylene mesh sling using a novel combination of surgical techniques including total or near total mesh excision, urinary tract reconstruction, and concomitant pubovaginal sling with autologous rectus fascia in a single operation. We retrospectively reviewed the medical records of 189 patients undergoing transvaginal removal of polypropylene mesh from the lower urinary tract or vagina. The focus of this study is 21 patients with LUT mesh perforation after mid-urethral polypropylene mesh sling. We excluded patients with LUT mesh perforation from prolapse kits (n = 4) or sutures (n = 11), or mesh that was removed because of isolated vaginal wall exposure without concomitant LUT perforation (n = 164). Twenty-one patients underwent surgical removal of mesh through a transvaginal approach or combined transvaginal/abdominal approaches. The location of the perforation was the urethra in 14 and the bladder in 7. The mean follow-up was 22 months. There were no major intraoperative complications. All patients had complete resolution of the mesh complication and the primary symptom. Of the patients with urethral perforation, continence was achieved in 10 out of 14 (71.5 %). Of the patients with bladder perforation, continence was achieved in all 7. Total or near total removal of lower urinary tract (LUT) mesh perforation after mid-urethral polypropylene mesh sling can completely resolve LUT mesh perforation in a single operation. A concomitant pubovaginal sling can be safely performed in efforts to treat existing SUI or avoid future surgery for SUI.

  4. Surface orientation effects on bending properties of surgical mesh are independent of tensile properties. (United States)

    Simon, David D; Andrews, Sharon M; Robinson-Zeigler, Rebecca; Valdes, Thelma; Woods, Terry O


    Current mechanical testing of surgical mesh focuses primarily on tensile properties even though implanted devices are not subjected to pure tensile loads. Our objective was to determine the flexural (bending) properties of surgical mesh and determine if they correlate with mesh tensile properties. The flexural rigidity values of 11 different surgical mesh designs were determined along three textile directions (machine, cross-machine, and 45° to machine; n = 5 for each) using ASTM D1388-14 while tracking surface orientation. Tensile testing was also performed on the same specimens using ASTM D882-12. Linear regressions were performed to compare mesh flexural rigidity to mesh thickness, areal mass density, filament diameter, ultimate tensile strength, and maximum extension. Of 33 mesh specimen groups, 30 had significant differences in flexural rigidity values when comparing surface orientations (top and bottom). Flexural rigidity and mesh tensile properties also varied with textile direction (machine and cross-machine). There was no strong correlation between the flexural and tensile properties, with mesh thickness having the best overall correlation with flexural rigidity. Currently, surface orientation is not indicated on marketed surgical mesh, and a single mesh may behave differently depending on the direction of loading. The lack of correlation between flexural stiffness and tensile properties indicates the need to examine mesh bending stiffness to provide a more comprehensive understanding of surgical mesh mechanical behaviors. Further investigation is needed to determine if these flexural properties result in the surgical mesh behaving mechanically different depending on implantation direction. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 854-862, 2018. © 2017 Wiley Periodicals, Inc.

  5. Surgical Management of Pelvic floor Prolapse in women using Mesh

    African Journals Online (AJOL)


    polytetrafluoroethylene) . This article reviews our experience with polypropylene mesh in pelvic floor repair at the. Southern General Hospital Glasgow. The objective was to determine the safety and effectiveness of the prolene mesh in the repair ...

  6. Polypropylene Surgical Mesh Coated with Extracellular Matrix Mitigates the Host Foreign Body Response (United States)

    Wolf, Matthew T.; Carruthers, Christopher A.; Dearth, Christopher L.; Crapo, Peter M.; Huber, Alexander; Burnsed, Olivia A.; Londono, Ricardo; Johnson, Scott A.; Daly, Kerry A.; Stahl, Elizabeth C.; Freund, John M.; Medberry, Christopher J.; Carey, Lisa E.; Nieponice, Alejandro; Amoroso, Nicholas J.; Badylak, Stephen F.


    Surgical mesh devices composed of synthetic materials are commonly used for ventral hernia repair. These materials provide robust mechanical strength and are quickly incorporated into host tissue; factors which contribute to reduced hernia recurrence rates. However, such mesh devices cause a foreign body response with the associated complications of fibrosis and patient discomfort. In contrast, surgical mesh devices composed of naturally occurring extracellular matrix (ECM) are associated with constructive tissue remodeling, but lack the mechanical strength of synthetic materials. A method for applying a porcine dermal ECM hydrogel coating to a polypropylene mesh is described herein with the associated effects upon the host tissue response and biaxial mechanical behavior. Uncoated and ECM coated heavy-weight BARD™ Mesh were compared to the light-weight ULTRAPRO™ and BARD™ Soft Mesh devices in a rat partial thickness abdominal defect overlay model. The ECM coated mesh attenuated the pro-inflammatory response compared to all other devices, with a reduced cell accumulation and fewer foreign body giant cells. The ECM coating degraded by 35 days, and was replaced with loose connective tissue compared to the dense collagenous tissue associated with the uncoated polypropylene mesh device. Biaxial mechanical characterization showed that all of the mesh devices were of similar isotropic stiffness. Upon explantation, the light-weight mesh devices were more compliant than the coated or uncoated heavy-weight devices. The present study shows that an ECM coating alters the default host response to a polypropylene mesh, but not the mechanical properties in an acute in vivo abdominal repair model. PMID:23873846

  7. Surgical management of pelvic floor prolapse in women using mesh ...

    African Journals Online (AJOL)

    The effectiveness and complications following PPM insertion were carefully documented. Results: A total of 57 repairs of various types of prosthetic materials were carried out over the study period. 30 patients had polypropylene mesh inserted, while 27had IVS. Of the patients who had PPM inserted 27(90%) had successful ...

  8. The Effect of Cyclic Loading on the Mechanical Performance of Surgical Mesh

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    Ho Y.C.


    Full Text Available Polymeric meshes in the form of knitted nets are commonly used in the surgical repair of pelvic organ prolapses. Although a number of these prosthetic meshes are commercially available, there is little published data on their mechanical performance, in particular on the change in stiffness under the repeated loading experienced in vivo. In this in vitro study, cyclic tensile loading was applied to rectangular strips of four different commercially available meshes. The applied force and resultant displacement was monitored throughout the tests in order to evaluate the change in stiffness. In addition, each mesh was randomly marked using indelible ink in order to permit the use of threedimensional digital image correlation to evaluate local displacements during the tests. However, the scale and form of the deformation experienced by some of the meshes made correlation difficult so that confirmation of the values of stiffness were only obtained for two meshes. The results demonstrate that all the meshes experience an increase in stiffness during cyclic loading, that in most cases cyclic creep occurs and in some cases large-scale, irreversible reorganisation of the mesh structure occurs after as few as 200 cycles at loads of the order of 10N.

  9. Mechanical behavior of surgical meshes for abdominal wall repair: In vivo versus biaxial characterization. (United States)

    Simón-Allué, R; Ortillés, A; Calvo, B


    Despite the widespread use of synthetic meshes in the surgical treatment of the hernia pathology, the election criteria of a suitable mesh for specific patient continues to be uncertain. Thus, in this work, we propose a methodology to determine in advance potential disadvantages on the use of certain meshes based on the patient-specific abdominal geometry and the mechanical features of the certain meshes. To that purpose, we have first characterized the mechanical behavior of four synthetic meshes through biaxial tests. Secondly, two of these meshes were implanted in several New Zealand rabbits with a total defect previously created on the center of the abdominal wall. After the surgical procedure, specimen were subjected to in vivo pneumoperitoneum tests to determine the immediate post-surgical response of those meshes after implanted in a healthy specimen. Experimental performance was recorded by a stereo rig with the aim of obtaining quantitative information about the pressure-displacement relation of the abdominal wall. Finally, following the procedure presented in prior works (Simón-Allué et al., 2015, 2017), a finite element model was reconstructed from the experimental measurements and tests were computationally reproduced for the healthy and herniated cases. Simulations were compared and validated with the in vivo behavior and results were given along the abdominal wall in terms of displacements, stresses and strain. Mechanical characterization of the meshes revealed Surgipro TM as the most rigid implant and Neomesh SuperSoft® as the softer, while other two meshes (Neomesh Soft®, Neopore®) remained in between. These two meshes were employed in the experimental study and resulted in similar effect in the abdominal wall cavity and both were close to the healthy case. Simulations confirmed this result while showed potential objections in the case of the other two meshes, due to high values in stresses or elongation that may led to discomfort in real

  10. A pregnant woman with a surgical site infection after mesh repair of an abdominal wall incisional hernia: a case report. (United States)

    Ozaki, Kana; Tanimura, Kenji; Ebina, Yasuhiko; Kanemitsu, Kiyonori; Yamada, Hideto


    Surgical meshes are widely used in incisional hernia repair. However, there are no reports of pregnancies complicated by infection of surgical meshes used for hernia repair. This is the first case report of a pregnant woman who experienced surgical site infection associated with surgical mesh used for repair of an abdominal wall incisional hernia. We report a case of a 41-year-old pregnant Japanese woman with surgical site infection after mesh repair of an abdominal wall incisional hernia. She was diagnosed with an abdominal wall incisional hernia at 3 months after her third cesarean section, and she underwent an operation of hernia repair with use of monofilament polypropylene mesh 7 months after the third cesarean section. However, a surgical site infection associated with surgical mesh occurred. During antibiotic treatment, she was found to be pregnant. She was referred to our hospital at 13 weeks and 2 days of gestation. The surgeons removed the infected mesh at 16 weeks and 3 days of gestation. Neither the hernia nor infection at the surgical site recurred throughout pregnancy. We planned a cesarean section using a transverse uterine fundal incision method with an upper abdominal incision. The patient delivered a 2478-g healthy female infant. The present report shows that removal of mesh can safely control surgical site infection during pregnancy.

  11. Surgical treatment of subcostal incisional hernia with polypropylene mesh - analysis of late results

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    Marco Antonio de Oliveira Peres

    Full Text Available OBJECTIVE: To evaluate the results of subcostal incisional hernia repair using polypropylene mesh, the technical aspects of musculo-aponeurotic reconstruction, routine fixation of supra-aponeurotic mesh and follow-up for five years.METHODS: We conducted a retrospective study that assessed 24 patients undergoing subcostal incisional hernia repair with use of polypropylene mesh; 15 patients (62.5% were female; ages ranged from 33 to 82, and 79.1% had comorbidities.RESULTS: Early complications: three cases (12.5% of wound infection, three cases (12.5% of seroma, one case (4.1% of hematoma; and one case (4.1% of wound dehiscence. Late complications occurred in one case (4.1% of hernia recurrence attributed to technical failure in the fixation of the mesh and in one case (4.1% of chronic pain. There were no cases of exposure or rejection of the mesh.CONCLUSION: The subcostal incisional hernia, though not very relevant, requires adequate surgical treatment. Its surgical correction involves rebuilding the muscle-aponeurotic defect, supra-aponeurotic fixation of polypropylene mesh, with less complexity and lower rates of complications and recurrences.

  12. The Importance of Registries in the Postmarketing Surveillance of Surgical Meshes. (United States)

    Köckerling, Ferdinand; Simon, Thomas; Hukauf, Martin; Hellinger, Achim; Fortelny, Rene; Reinpold, Wolfgang; Bittner, Reinhard


    To assess the role of registries in the postmarketing surveillance of surgical meshes. To date, surgical meshes are classified as group II medical devices. Class II devices do not require premarket clearance by clinical studies. Ethicon initiated a voluntary market withdrawal of Physiomesh for laparoscopic use after an analysis of unpublished data from the 2 large independent hernia registries-Herniamed German Registry and Danish Hernia Database. This paper now presents the relevant data from the Herniamed Registry. The present analysis compares the prospective perioperative and 1-year follow-up data collected for all patients with incisional hernia who had undergone elective laparoscopic intraperitoneal onlay mesh repair either with Physiomesh (n = 1380) or with other meshes recommended in the guidelines (n = 3834). Patients with Physiomesh repair had a markedly higher recurrence rate compared with the other recommended meshes (12.0% vs 5.0%; P manufacturing company must be taken into account.This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

  13. Hip Joint Replacement Using Monofilament Polypropylene Surgical Mesh: An Animal Model

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    Jacek Białecki


    Full Text Available Hip joint dysplasia is a deformation of the articular elements (pelvic acetabulum, head of the femur, and/or ligament of the head of the femur leading to laxity of the hip components and dislocation of the femoral head from the pelvic acetabulum. Diagnosis is based on symptoms observed during clinical and radiological examinations. There are two treatment options: conservative and surgical. The classic surgical procedures are juvenile pubic symphysiodesis (JPS, triple pelvic osteotomy (TPO, total hip replacement (THR, and femoral head and neck resection (FHNE. The aim of this experiment was to present an original technique of filling the acetabulum with a polypropylene implant, resting the femoral neck directly on the mesh. The experiment was performed on eight sheep. The clinical value of the new surgical technique was evaluated using clinical, radiological, and histological methods. This technique helps decrease the loss of limb length by supporting the femoral neck on the mesh equivalent to the femoral head. It also reduces joint pain and leads to the formation of stable and mobile pseudarthrosis. The mesh manifested osteoprotective properties and enabled the formation of a stiff-elastic connection within the hip joint. The method is very cost-effective and the technique itself is simple to perform.

  14. Hip Joint Replacement Using Monofilament Polypropylene Surgical Mesh: An Animal Model (United States)

    Białecki, Jacek; Klimowicz-Bodys, Małgorzata Dorota; Wierzchoś, Edward; Kołomecki, Krzysztof


    Hip joint dysplasia is a deformation of the articular elements (pelvic acetabulum, head of the femur, and/or ligament of the head of the femur) leading to laxity of the hip components and dislocation of the femoral head from the pelvic acetabulum. Diagnosis is based on symptoms observed during clinical and radiological examinations. There are two treatment options: conservative and surgical. The classic surgical procedures are juvenile pubic symphysiodesis (JPS), triple pelvic osteotomy (TPO), total hip replacement (THR), and femoral head and neck resection (FHNE). The aim of this experiment was to present an original technique of filling the acetabulum with a polypropylene implant, resting the femoral neck directly on the mesh. The experiment was performed on eight sheep. The clinical value of the new surgical technique was evaluated using clinical, radiological, and histological methods. This technique helps decrease the loss of limb length by supporting the femoral neck on the mesh equivalent to the femoral head. It also reduces joint pain and leads to the formation of stable and mobile pseudarthrosis. The mesh manifested osteoprotective properties and enabled the formation of a stiff-elastic connection within the hip joint. The method is very cost-effective and the technique itself is simple to perform. PMID:24987672

  15. Biodegradable rifampicin-releasing coating of surgical meshes for the prevention of bacterial infections

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    Reinbold J


    Full Text Available Jochen Reinbold,1 Teresa Hierlemann,1 Lukas Urich,1 Ann-Kristin Uhde,1 Ingrid Müller,2 Tobias Weindl,3 Ulrich Vogel,4 Christian Schlensak,1 Hans Peter Wendel,1 Stefanie Krajewski1 1Department of Thoracic and Cardiovascular Surgery, University Hospital Tübingen, Tübingen, 2Department of Pharmaceutical Engineering, Albstadt-Sigmaringen University of Applied Science, Albstadt, 3Aimecs® GmbH Medical Solutions, Pfarrkirchen, 4Institute of Pathology and Neuropathology, Tübingen, Germany Abstract: Polypropylene mesh implants are routinely used to repair abdominal wall defects or incisional hernia. However, complications associated with mesh implantation, such as mesh-related infections, can cause serious problems and may require complete surgical removal. Hence, the aim of the present study was the development of a safe and efficient coating to reduce postoperative mesh infections. Biodegradable poly(lactide-co-glycolide acid microspheres loaded with rifampicin as an antibacterial agent were prepared through single emulsion evaporation method. The particle size distribution (67.93±3.39 µm for rifampicin-loaded microspheres and 64.43±3.61 µm for unloaded microspheres was measured by laser diffraction. Furthermore, the encapsulation efficiency of rifampicin (61.5%±2.58% was detected via ultraviolet–visible (UV/Vis spectroscopy. The drug release of rifampicin-loaded microspheres was detected by UV/Vis spectroscopy over a period of 60 days. After 60 days, 92.40%±3.54% of the encapsulated rifampicin has been continuously released. The viability of BJ fibroblasts after incubation with unloaded and rifampicin-loaded microspheres was investigated using an MTT (3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay, which showed no adverse effects on the cells. Furthermore, the antibacterial impact of rifampicin-loaded microspheres and mesh implants, coated with the antibacterial microspheres, was investigated using an agar diffusion

  16. Computational modeling of abdominal hernia laparoscopic repair with a surgical mesh. (United States)

    Todros, Silvia; Pachera, Paola; Baldan, Nicola; Pavan, Piero G; Pianigiani, Silvia; Merigliano, Stefano; Natali, Arturo N


    Although new techniques and prostheses have been introduced in ventral hernia surgery, abdominal hernia repair still presents complications, such as recurrence, pain, and discomfort. Thus, this work implements a computational method aimed at evaluating biomechanical aspects of the abdominal hernia laparoscopic repair, which can support clinical research tailored to hernia surgery. A virtual solid model of the abdominal wall is obtained from MRI scans of a healthy subject. The mechanical behavior of muscular and fascial tissues is described by constitutive formulations with specific parameters. A defect is introduced to reproduce an incisional hernia. Laparoscopic repair is mimicked via intraperitoneal positioning of a surgical mesh. Numerical analyses are performed to evaluate the mechanical response of the abdominal wall in healthy, herniated and post-surgery configurations, considering physiological intra-abdominal pressures. During the deformation of the abdominal wall at increasing pressures, a percentage displacement increment up to 6% is found in the herniated condition, while the mechanical behavior of the repaired abdomen is similar to the healthy one. In the pressure range between 8 mmHg and 55 mmHg, the herniated abdomen shows an incremental stiffness differing of 7% with respect to the healthy condition, while the post-surgery condition shows an increase of the incremental stiffness up to 58%. This computational approach may be exploited to investigate different aspects of abdominal wall surgical repair, including mesh mechanical characteristics and positioning. Numerical modeling offers a helpful support for selecting the best-fitting prosthesis for customize pre-surgery planning.

  17. Pelvic organ prolapse surgical management in Portugal and FDA safety communication have an impact on vaginal mesh. (United States)

    Mascarenhas, Teresa; Mascarenhas-Saraiva, Miguel; Ricon-Ferraz, Amélia; Nogueira, Paula; Lopes, Fernando; Freitas, Alberto


    Pelvic organ prolapse (POP) surgery has lately gained importance in gynecological practice. This study aims to characterize the evolution of POP surgical procedures conducted in Portugal in the last decade and the impact of an FDA 2011 safety communication on mesh POP surgeries. Trends in the surgical management of POP were assessed using the Portuguese National Medical Registry. We considered all records of women with diagnosis of genital prolapse from 1 January 2000 to 31 December 2012. Additionally, we also conducted a survey among members of the Portuguese Society of Urogynecology to evaluate current practices in the surgical management of POP. From 2000 to 2012, 46,819 diagnoses of genital prolapse were registered, with a 105 % increase during the study period (2,368 in 2000 to 4,941 in 2012). POP mesh surgery represented only 6 % of total prolapse diagnoses, but mesh use greatly increased up to 2011, when only a slight increase was registered. Among gynecologists who responded to the questionnaire, there was considerable variability on the procedures of choice to treat POP. Fifty-seven per cent of respondents performed vaginal mesh POP surgery, but only 27 % of those actually reported having changed their practice after the FDA 2011 safety communication. Surgical procedures for POP conducted in Portugal greatly increased over the last decade. The use of surgical meshes is still limited, but despite FDA safety communication it has increased over the years, with a slight increase in 2012, which illustrates the need for further analyses in the coming years.

  18. Morphological aspects of surgical meshes as a risk factor for bacterial colonization

    NARCIS (Netherlands)

    Engelsman, A. F.; van der Mei, H. C.; Busscher, H. J.; Ploeg, R. J.

    Background: Prosthetic meshes are increasingly popular in abdominal wall reconstructive surgery owing to a reduction in hernia recurrence rate. Individual meshes have been evaluated with respect to the formation of infectious biofilms, but no comprehensive comparison yet exists. The aim of this

  19. The Relationship between the Mechanism of Zinc Oxide Crystallization and Its Antimicrobial Properties for the Surface Modification of Surgical Meshes (United States)

    Fiedot, Marta; Maliszewska, Irena; Rac-Rumijowska, Olga; Suchorska-Woźniak, Patrycja; Lewińska, Agnieszka; Teterycz, Helena


    Surgical meshes were modified with zinc oxide (ZnO) using a chemical bath deposition method (CBD) at 50 °C, 70 °C, or 90 °C, in order to biologically activate them. Scanning electron microscopy (SEM), mass changes, and X-ray diffraction measurements revealed that at low temperatures Zn(OH)2 was formed, and that this was converted into ZnO with a temperature increase. The antimicrobial activity without light stimulation of the ZnO modified Mersilene™ meshes was related to the species of microorganism, the incubation time, and the conditions of the experiment. Generally, cocci (S. aureus, S. epidermidis) and yeast (C. albicans) were more sensitive than Gram-negative rods (E. coli). The differences in sensitivity of the studied microorganisms to ZnO were discussed. The most active sample was that obtained at 90 °C. The mechanism of antimicrobial action of ZnO was determined by various techniques, such as zeta potential analysis, electron paramagnetic resonance (EPR) spectroscopy, SEM studies, and measurements of Zn(II) and reactive oxygen species (ROS) concentration. Our results confirmed that the generation of free radicals was crucial, which occurs on the surface of crystalline ZnO. PMID:28772718

  20. TOT versus TVT – mesh surgical treatment in stress urinary incontinence

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    Ovidiu Bratu


    Full Text Available Introduction: Stress urinary incontinence is a highly debilitating condition, with an important impact over the quality of life. When the conservative treatment fails, the surgical treatment is a viable solution. Minimally invasive sling procedures have become the gold standard of surgical management for stress urinary incontinence (SUI in women. Material and methods: The study was conducted on 68 patients with stress urinary incontinence, 52 have undergone the retropubic tension-free vaginal tape and 16 patients were operated using the transobturator tape procedure. All the patients were evaluated before the operation and the indication of the surgical treatment was established on the basis of physical examination (all the patients had positive cough test, abdominal ultrasound (to determine postvoid residual urine volume, urinalysis and urine culture (the majority of the patients have had before the operation recurrent urinary tract infections. Results: The satisfaction was similar in both groups of patients, with an average satisfaction rate of 91% for TVT and 86% for the patients who have undergone TOT procedure. The patients were in a proportion of 78,9% at menopause, with an average number of natural births of 1.9 and a mean BMI of 28.2. Regarding the surgical duration, this has varied between 20 and 40 minutes, being higher in the TVT cases (up to 5-7 minutes longer than TOT, because cystoscopy was performed during the operation to verify if the bladder was perforated or not. The urethral catheter was removed immediately after the operation in the case of the TOT procedure and in the day after the operation for the patients who have undergone TVT procedures (all of these patients associated genital prolapse. The hospitalization time was 3 days. We haven’t encountered significant intraoperative and postoperative complications. Conclusions: The TOT and TVT procedures have proven to be highly effective and safe methods in the treatment of

  1. A Comparison of the Incidence of Early Postoperative Infections between Patients Using Synthetic Mesh and Those Undergoing Traditional Pelvic Reconstructive Surgical Procedures

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    Jaromír Mašata


    Full Text Available New mesh-related complications such as erosion, etc., can result from abnormal postoperative healing due to surgical site infection. The aim of our study was to compare systemic inflammatory responses and the incidence of early infectious complications after reconstructive surgery using synthetic mesh and after traditional vaginal wall repair. In this prospective observational study 99 women with symptomatic pelvic organ prolapse were included; 55 women underwent traditional repair and 44 repair using mesh. After the procedure infectious complications were monitored. The patients who underwent reconstructive surgery using mesh material were more likely to have febrile morbidity in the postoperative period than the patients who had been treated with traditional repair (p=0.031; there was a higher incidence of combination febrile morbidity with elevated C-reactive protein (CRP > 50 mg/l; p=0.046, and a higher incidence of CRP increase over 30 mg/l; p=0.005. Reconstructive procedures using synthetic mesh are accompanied by a higher incidence of early post-operative infectious complications.

  2. Surgical management of a De Garengeot’s hernia using a biologic mesh: A case report and review of literature

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    Amandine Klipfel


    Conclusion: The De Garengeot hernia is an uncommon differential diagnosis for patients presenting with clinical signs of strangled femoral hernia. Although hernia repairs with a synthetic mesh in the presence of appendicitis have been reported, we describe a case of femoral hernia repair using a biologic mesh, in a patient with a De Garengot hernia.

  3. Surgical management of large segmental femoral and radial bone defects in a dog: through use of a cylindrical titanium mesh cage and a cancellous bone graft. (United States)

    Segal, U; Shani, J


    In this case report, we describe the use of a cylindrical titanium mesh cage combined with cancellous bone graft to surgically manage large segmental bone defects in a dog. A seven-year-old, neutered male cross-breed dog, with highly comminuted fractures of the right femur and the left radius and ulna, was referred for treatment. Previous open reduction and internal fixation of these fractures had failed. Following implant removal and debridement of each bone, a 71 mm segmental femoral defect and a 27 mm segmental radial defect were present. A commercially available cylindrical titanium mesh cage was filled with ss-tricalcium phosphate crystals mixed with an equal volume of autogenous cancellous bone graft. The mesh cage was aligned with the proximal and distal parts of each bone using an intramedullary pin passing through the cage, and a locking plate was applied to the proximal and distal fracture fragments to produce compression against the titanium cage. The dog had a successful long-term clinical outcome, and radiographic examination at 22 and 63 weeks after surgery showed the formation of remodelling bridging callus that was continuous across the titanium cage in each of the fractures. Due to the relative simplicity of the technique and the favourable outcome in this case, it should be considered an option when managing comminuted fractures with large bone defects.

  4. Surgical repair of incisional ventral hernias: tension-free technique using prosthetic materials (expanded polytetrafluoroethylene Gore-Tex Dual Mesh). (United States)

    Chrysos, E; Athanasakis, E; Saridaki, Z; Kafetzakis, A; Dimitriadou, D; Koutsoumpas, V; Chalkiadakis, G; Xynos, E; Zoras, O


    Repairing an incisional ventral hernia is a major challenge for a surgeon. The high recurrence rates observed during hernia repair by tissue approximation led to development of tension-free procedures by using prosthetic materials. The purpose of this study is to report the results of a tension-free repair technique using expanded polytetrafluoroethylene Gore-Tex Dual Mesh (Gore-Tex Soft Tissue Patch, W.L. Gore and Associates Inc, Flagstaff, AZ) in patients with primary or recurrent incisional ventral hernias. Over 3 years, 52 patients with incisional hernias have undergone this procedure in our clinic. Fourteen of them had recurrent hernias which had been primarily repaired by Mayo hernioplasty. Six of our patients had irreducible hernias preoperatively. Twenty-five patients had hernias on midline incisions, and the rest of them had hernias on transverse abdominal incisions. The median patient age was 65 years, and all were operated on under general anesthesia. The majority of the patients had 4 to 6 days of hospitalization. A subcutaneous seroma developed in eight patients. They all were treated by multiple paracentesis. Four of our patients experienced wound infection and were treated by mesh removal. None of the patients presented with cardiovascular or pulmonary complications. During the follow-up period, no other hernia recurrence, except the cases with mesh removal, has been noticed. The tension-free incisional hernia repair using expanded polytetrafluoroethylene mesh is, to our experience, a safe and easy procedure with no major morbidity or recurrence.

  5. Intense FDG Uptake around the Inguinal Surgical Mesh 5 Years after Operation: Case Report and Review of the Literature


    Bah?eci, Tatiana; Nursal, G?l Nihal; Ayd?n, Mehmet


    We present the case of a 40-year-old man who underwent a FDG PET/CT study for restaging of renal cell carcinoma treated with left nephrectomy, for suspected metastasis in lung and retroperitoneal lymph nodes. The patient had a history of left inguinal hernia repair with implantation of mesh prosthesis 5 years ago. PET/CT image revealed linear intense FDG uptake in left inguinal region most likely corresponding to a persistent foreign body reaction. In this article, a case with an intense FDG ...

  6. Trends in internet search activity, media coverage, and patient-centered health information after the FDA safety communications on surgical mesh for pelvic organ prolapse. (United States)

    Stone, Benjamin V; Forde, James C; Levit, Valerie B; Lee, Richard K; Te, Alexis E; Chughtai, Bilal


    In July 2011, the US Food and Drug Administration (FDA) issued a safety communication regarding serious complications associated with surgical mesh for pelvic organ prolapse, prompting increased media and public attention. This study sought to analyze internet search activity and news article volume after this FDA warning and to evaluate the quality of websites providing patient-centered information. Google Trends™ was utilized to evaluate search engine trends for the term "pelvic organ prolapse" and associated terms between 1 January 2004 and 31 December 2014. Google News™ was utilized to quantify the number of news articles annually under the term "pelvic organ prolapse." The search results for the term "pelvic organ prolapse" were assessed for quality using the Health On the Net Foundation (HON) certification. There was a significant increase in search activity from 37.42 in 2010 to 57.75 in 2011, at the time of the FDA communication (p = 0.021). No other annual interval had a statistically significant increase in search activity. The single highest monthly search activity, given the value of 100, was August 2011, immediately following the July 2011 notification, with the next highest value being 98 in July 2011. Linear regression analysis of news articles per year since the FDA communication revealed r 2  = 0.88, with a coefficient of 186. Quality assessment demonstrated that 42 % of websites were HON-certified, with .gov sites providing the highest quality information. Although the 2011 FDA safety communication on surgical mesh was associated with increased public and media attention, the quality of relevant health information on the internet remains of poor quality. Future quality assurance measures may be critical in enabling patients to play active roles in their own healthcare.

  7. How to Surgically Remove the Permanent Mesh Ring after the Onstep Procedure for Alleviation of Chronic Pain following Inguinal Hernia Repair

    DEFF Research Database (Denmark)

    Öberg, Stina; Andresen, Kristoffer; Rosenberg, Jacob


    A promising open inguinal hernia operation called Onstep was developed in 2005. The technique is without sutures to the surrounding tissue, causing minimal tension. A specific mesh is used with a memory recoil ring in the border, which may cause pain superficial to the lateral part of the mesh...... for slender patients. The aim of this study was to illustrate an easy procedure that alleviates/removes the pain. A male patient had persistent pain six months after the Onstep operation and therefore had a ring removal operation. The procedure is presented as a video and a protocol. At the eleven......-month follow-up, the patient was free of pain, without a recurrence. It is advised to wait some months after the initial hernia repair before removing the ring, since the mesh needs time to become well integrated into the surrounding tissue. The operation is safe and easy to perform, which is demonstrated...

  8. How to Surgically Remove the Permanent Mesh Ring after the Onstep Procedure for Alleviation of Chronic Pain following Inguinal Hernia Repair

    Directory of Open Access Journals (Sweden)

    Stina Öberg


    Full Text Available A promising open inguinal hernia operation called Onstep was developed in 2005. The technique is without sutures to the surrounding tissue, causing minimal tension. A specific mesh is used with a memory recoil ring in the border, which may cause pain superficial to the lateral part of the mesh for slender patients. The aim of this study was to illustrate an easy procedure that alleviates/removes the pain. A male patient had persistent pain six months after the Onstep operation and therefore had a ring removal operation. The procedure is presented as a video and a protocol. At the eleven-month follow-up, the patient was free of pain, without a recurrence. It is advised to wait some months after the initial hernia repair before removing the ring, since the mesh needs time to become well integrated into the surrounding tissue. The operation is safe and easy to perform, which is demonstrated in a video.

  9. Multicenter, Prospective, Longitudinal Study of the Recurrence, Surgical Site Infection, and Quality of Life After Contaminated Ventral Hernia Repair Using Biosynthetic Absorbable Mesh: The COBRA Study

    NARCIS (Netherlands)

    Rosen, M.J.; Bauer, J.J.; Harmaty, M.; Carbonell, A.M.; Cobb, W.S.; Matthews, B.; Goldblatt, M.I.; Selzer, D.J.; Poulose, B.K.; Hansson, B.M.E.; Rosman, C.; Chao, J.J.; Jacobsen, G.R.


    OBJECTIVE: The aim of the study was to evaluate biosynthetic absorbable mesh in single-staged contaminated (Centers for Disease Control class II and III) ventral hernia (CVH) repair over 24 months. BACKGROUND: CVH has an increased risk of postoperative infection. CVH repair with synthetic or

  10. One-Year Surgical Outcomes and Quality of Life after Minimally Invasive Sling Procedures for the Treatment of Female Stress Urinary Incontinence: TVT SECUR® vs. CureMesh® (United States)

    Joo, Young Min; Choe, Jin Ho


    Purpose We compared the efficacy and safety of two minimally invasive sling procedures used to treat female stress urinary incontinence (SUI), tension-free vaginal tape (TVT) SECUR® and CureMesh®, and assessed the 1-year surgical outcomes. Materials and Methods Sixty women with SUI were assigned to undergo either the TVT SECUR (n=38) or CureMesh (n=22) procedures between April 2007 and June 2008. Patients were monitored via outpatient visits at 1 month, 3 months, and 1 year after surgery. The efficacy of these procedures was evaluated by the cough test or by a urodynamic study. At these postoperative visits, the patients also completed several questionnaires, including incontinence quality of life, patient's perception of urgency severity, the scored form of the Bristol Female Lower Urinary Tract Symptoms, visual analog scale, and questions about perceived benefit, satisfaction, and willingness to undergo the same operation again. The objective cure rate was defined as no leakage during the cough test with a full bladder. The subjective cure rate was evaluated by self-assessment of goal achievement performed 1 year postoperatively. Results The two groups were similar in preoperative characteristics and urodynamic parameters. The objective cure rates were similar between TVT SECUR and CureMesh (68.4% vs. 77.3%). All respondents reported improvement after surgery. There were no intra-operative complications. Conclusions Our results showed that the TVT SECUR and CureMesh procedures are both safe and simple to perform and have no significant differences in efficacy. Comparative studies with long-term follow-up are warranted to determine the true efficacy of these procedures. PMID:20495697

  11. Spherical geodesic mesh generation

    Energy Technology Data Exchange (ETDEWEB)

    Fung, Jimmy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kenamond, Mark Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Burton, Donald E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Shashkov, Mikhail Jurievich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    In ALE simulations with moving meshes, mesh topology has a direct influence on feature representation and code robustness. In three-dimensional simulations, modeling spherical volumes and features is particularly challenging for a hydrodynamics code. Calculations on traditional spherical meshes (such as spin meshes) often lead to errors and symmetry breaking. Although the underlying differencing scheme may be modified to rectify this, the differencing scheme may not be accessible. This work documents the use of spherical geodesic meshes to mitigate solution-mesh coupling. These meshes are generated notionally by connecting geodesic surface meshes to produce triangular-prismatic volume meshes. This mesh topology is fundamentally different from traditional mesh topologies and displays superior qualities such as topological symmetry. This work describes the geodesic mesh topology as well as motivating demonstrations with the FLAG hydrocode.

  12. Mesh network simulation


    Pei, Ping; Petrenko, Y. N.


    A Mesh network simulation framework which provides a powerful and concise modeling chain for a network structure will be introduce in this report. Mesh networks has a special topologic structure. The paper investigates a message transfer in wireless mesh network simulation and how does it works in cellular network simulation. Finally the experimental result gave us the information that mesh networks have different principle in transmission way with cellular networks in transmission, and multi...

  13. Pectus excavatum repair using Prolene polypropylene mesh. (United States)

    Rasihashemi, Seyed Ziaeddin; Ramouz, Ali


    We aimed to assess the clinical outcomes of our surgical technique for repair of pectus excavatum using Prolene polypropylene mesh. Among 29 patients with pectus excavatum, the major complaint was cosmetic dissatisfaction, and the main symptom was exercise dyspnea in 15 patients. The Haller index used to assess pectus excavatum severity; it was significant in 22 patients. In all patients, a 2-layer sheet of Prolene polypropylene mesh was placed behind the sternum. No serious complication was observed postoperatively, and all patients were satisfied with the cosmetic result. Mitral valve prolapse improved in all cases after 3 months. Spirometry revealed improved pulmonary function after surgery. With due attention to the advantages of Prolene polypropylene mesh, such as remaining permanently in place, adapting to various stresses encountered in the body, resisting degradation by tissue enzymes, and trimming without unraveling, we concluded that this mesh is suitable for use as posterior sternal support in pectus excavatum patients. © The Author(s) 2016.


    Gogoladze, M; Kiladze, M; Chkhikvadze, T; Jiqia, D


    Improving the results of hernia treatment and prevention of complications became a goal of our research which included two parts - experimental and clinical. Histomorphological and bacteriological researches showed that the best result out of the 3 control groups was received in case of covering implant "Coladerm"+ with chlorhexidine. Based on the experiment results working process continued in clinics in order to test and introduce new "coladerm"+ chlorhexidine covered poliprophilene meshes into practice. For clinical illustration there were 60 patients introduced to the research who had hernioplasty procedures by different nets: I group - standard meshes+"coladerm"+chlorhexidine, 35 patients; II group - standard meshes +"coladerm", 15 patients; III group - standard meshes, 10 patients. Assessment of the wound and echo-control was done post-surgery on the 8th, 30th and 90th days. This clinical research based on the experimental results once again showed the best anti-microbe features of new antiseptic polymeric biocomposite meshes (standard meshes+"coladerm"+chlorhexidine); timely termination of regeneration and reparation processes without any post-surgery suppurative complications. We hope that new antiseptic polymeric biocomposite meshes presented by us will be successfully used in surgical practice of hernia treatment based on and supported by expermental-clinical research.

  15. Solution adaptive mesh using moving mesh method

    International Nuclear Information System (INIS)

    Tilak, A.S.; Tong, A.Y.; Liao, G.


    This work deals with mesh adaptation strategy to enhance the accuracy of numerical solution of partial differential equations. This was achieved economically by employing the Moving Grid Finite Difference Method. The method was reformulated as first order div-curl system. This system was then solved using the Least Square Finite Element method (LSFEM). The reformulation of the method has two desirable effects. Firstly, it eliminates the expensive gradient computation in the original method and secondly it allows the method to be employed for mesh adaptation with dynamic boundaries. A 2-D general finite element code implementing the mesh adaptation method based on LSFEM, capable of analyzing self-adjoint problems in elasticity and heat transfer with variety of boundary conditions, sources or sinks was developed and thoroughly validated. The code was used to analyze and adapt mesh for problems in heat transfer and elasticity. The method was found to perform satisfactorily in all test cases. (author)

  16. Preliminary Results on Polypropylene Mesh Use for Abdominal ...

    African Journals Online (AJOL)

    Background: Incisional hernia is a major surgical problem. Several methods of hernia repair have been described but their outcome has been disappointing. This preliminary retrospective study reports on our experience with polypropylene mesh repair. Methods: The technique of mesh placement on anterior rectus ...

  17. Role of biological mesh in surgical treatment of paracolostomy hernias Uso de prótese biológica no tratamento cirúrgico de hérnias paracolostômicas

    Directory of Open Access Journals (Sweden)

    Sergio Eduardo Alonso Araujo


    Full Text Available BACKGROUND: Paracolostomy hernia is a frequent complication of intestinal stoma. Its correction can be made through relocation of the colostomy or by keeping it in place and performing abdominal wall reinforcement through direct suturing with or without a prosthesis. METHOD: Results of surgical treatment of paracolostomy hernias were analyzed in 22 patients who underwent surgery in our hospital during the past 15 years, with or without biological mesh (bovine pericardium. All patients had terminal colostomies after abdominoperineal excision of the rectum. RESULTS: In 15 (68.2% patients, hernia correction was made by maintaining the colostomy in place, in 2 of them (9.1% without reinforcement, and in the other 13 (59.1% through reinforcement of the aponeurosis with biological mesh. In the 7 (31.8% other patients, hernia correction was accomplished by relocation of the colostomy. The mean follow-up period was 50.2 months. Recurrence was observed in 3 (13.6% patients after a median of 16 months post-correction. CONCLUSION: Paracolostomy hernia remains a surgical challenge due to its high recurrence rate. Primary repair using a prosthesis of biological material may be preferable since muscle-aponeurotic weakness is frequently observed.Hérnias paracolostômicas são complicações freqüentes de estomas intestinais. A correção pode ser realizada através do seu reposicionamento ou mantendo a mesma localização, associada ao reforço da parede abdominal com ou sem o emprego de prótese. MÉTODOS: Os resultados do tratamento cirúrgico de hérnias paracolostômicas são analisados em 22 pacientes em nosso serviço nos últimos 15 anos. Todos os pacientes eram portadores de colostomias terminais após ressecção abdominoperineal do reto. RESULTADOS: Em 15 (68,2% pacientes, a correção da hérnia foi realizada mantendo-se a colostomia no local original, em 2 (9,1% deles através de herniorrafia simples e em 13 (59,1% com reforço da aponeurose com

  18. Open preperitoneal groin hernia repair with mesh

    DEFF Research Database (Denmark)

    Andresen, Kristoffer; Rosenberg, Jacob


    BACKGROUND: For the repair of inguinal hernias, several surgical methods have been presented where the purpose is to place a mesh in the preperitoneal plane through an open access. The aim of this systematic review was to describe preperitoneal repairs with emphasis on the technique. DATA SOURCES......: A systematic review was conducted and reported according to the PRISMA statement. PubMed, Cochrane library and Embase were searched systematically. Studies were included if they provided clinical data with more than 30 days follow up following repair of an inguinal hernia with an open preperitoneal mesh......-analysis. Open preperitoneal techniques with placement of a mesh through an open approach seem promising compared with the standard anterior techniques. This systematic review provides an overview of these techniques together with a description of surgical methods and clinical outcomes....

  19. Open preperitoneal groin hernia repair with mesh

    DEFF Research Database (Denmark)

    Andresen, Kristoffer; Rosenberg, Jacob


    Background For the repair of inguinal hernias, several surgical methods have been presented where the purpose is to place a mesh in the preperitoneal plane through an open access. The aim of this systematic review was to describe preperitoneal repairs with emphasis on the technique. Data sources...... A systematic review was conducted and reported according to the PRISMA statement. PubMed, Cochrane library and Embase were searched systematically. Studies were included if they provided clinical data with more than 30 days follow up following repair of an inguinal hernia with an open preperitoneal mesh......-analysis. Open preperitoneal techniques with placement of a mesh through an open approach seem promising compared with the standard anterior techniques. This systematic review provides an overview of these techniques together with a description of surgical methods and clinical outcomes....

  20. Abdominal reoperation and mesh explantation following open ventral hernia repair with mesh. (United States)

    Liang, Mike K; Li, Linda T; Nguyen, Mylan T; Berger, Rachel L; Hicks, Stephanie C; Kao, Lillian S


    This study sought to identify the incidence, indications, and predictors of abdominal reoperation and mesh explantation following open ventral hernia repair with mesh (OVHR). A retrospective cohort study of all patients at a single institution who underwent an OVHR from 2000 to 2010 was performed. Patients who required subsequent abdominal reoperation or mesh explantation were compared with those who did not. Reasons for reoperation were recorded. The 2 groups were compared using univariate and multivariate analysis (MVA). A total of 407 patients were followed for a median (range) of 57 (1 to 143) months. Subsequent abdominal reoperation was required in 69 (17%) patients. The most common reasons for reoperation were recurrence and surgical site infection. Only the number of prior abdominal surgeries was associated with abdominal reoperation on MVA. Twenty-eight patients (6.9%) underwent subsequent mesh explantation. Only the Ventral Hernia Working Group grade was associated with mesh explantation on MVA. Abdominal reoperation and mesh explantation following OVHR are common. Overwhelmingly, surgical complications are themost common causes for reoperation and mesh explantation. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Resterilized Polypropylene Mesh for Inguinal Hernia Repair

    African Journals Online (AJOL)


    Apr 19, 2018 ... Cost, availability of mesh, and perhaps reluctance to adopt a new technique are factors which prevent widespread ..... critical to preventing postoperative surgical site infection which potentially increases the cost of ... not recorded in 10 years of practice an incident of wound infection. In vitro bacteriological ...

  2. Polypropylene mesh: evidence for lack of carcinogenicity (United States)

    Moalli, Pamela; Brown, Bryan; Reitman, Maureen T. F.


    Tumors related to the implantation of surgical grade polypropylene in humans have never been reported. In this commentary we present a balanced review of the information on what is known regarding the host response to polypropylene and provide data as to why the potential for carcinogenicity of polypropylene mesh is exceedingly small. PMID:24614956

  3. Collagen/Polypropylene composite mesh biocompatibility in abdominal wall reconstruction. (United States)

    Lukasiewicz, Aleksander; Skopinska-Wisniewska, Joanna; Marszalek, Andrzej; Molski, Stanislaw; Drewa, Tomasz


    Intraperitoneal placement of polypropylene mesh leads to extensive visceral adhesions and is contraindicated. Different coatings are used to improve polypropylene mesh properties. Collagen is a protein with unique biocompatibility and cell ingrowth enhancement potential. A novel acetic acid extracted collagen coating was developed to allow placement of polypropylene mesh in direct contact with viscera. The authors' aim was to evaluate the long-term influence of acetic acid extracted collagen coating on surgical aspects and biomechanical properties of polypropylene mesh implanted in direct contact with viscera, including complications, adhesions with viscera, strength of incorporation, and microscopic inflammatory reaction. Forty adult Wistar rats were divided into two groups: experimental (polypropylene mesh/acetic acid extracted collagen coating) and control (polypropylene mesh only). Astandardized procedure of mesh implantation was performed. Animals were killed 3 months after surgery and analyzed for complications, mesh area covered by adhesions, type of adhesions, strength of incorporation, and intensity of inflammatory response. The mean adhesion area was lower for polypropylene mesh/acetic acid extracted collagen coating (14.5 percent versus 69.9 percent, p polypropylene mesh are significantly reduced because of acetic acid extracted collagen coating. The collagen coating does not increase complications or induce alterations of polypropylene mesh incorporation.

  4. The mesh controversy [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Joshua A. Cohn


    Full Text Available Pelvic organ prolapse and stress urinary incontinence are common conditions for which approximately 11% of women will undergo surgical intervention in their lifetime. The use of vaginal mesh for pelvic organ prolapse and stress urinary incontinence rose rapidly in the early 2000s as over 100 mesh products were introduced into the clinical armamentarium with little regulatory oversight for their use. US Food and Drug Administration Public Health Notifications in 2008 and 2011, as well as reclassification of transvaginal mesh for prolapse to class III in early 2016, were a response to debilitating complications associated with transvaginal mesh placement in many women. The midurethral sling has not been subject to the same reclassification and continues to be endorsed as the “gold standard” for surgical management of stress urinary incontinence by subspecialty societies. However, litigators have not differentiated between mesh for prolapse and mesh for incontinence. As such, all mesh, including that placed for stress urinary incontinence, faces continued controversy amidst an uncertain future. In this article, we review the background of the mesh controversy, recent developments, and the anticipated role of mesh in surgery for prolapse and stress urinary incontinence going forward.

  5. Polypropylene mesh repair of a unilateral, congenital hernia in the inguinal region in a Thoroughbred filly (United States)

    Moorman, Valerie J.; Jann, Henry W.


    A 2-day-old Thoroughbred intact female was presented for a large subcutaneous swelling in the right inguinal region. Surgical repair was performed using a double layer polypropylene mesh. To the authors’ knowledge, there have been no previous reports of surgical repair of congenital body wall hernias with polypropylene mesh in foals. PMID:19721780

  6. Wireless mesh networks

    CERN Document Server

    Held, Gilbert


    Wireless mesh networking is a new technology that has the potential to revolutionize how we access the Internet and communicate with co-workers and friends. Wireless Mesh Networks examines the concept and explores its advantages over existing technologies. This book explores existing and future applications, and examines how some of the networking protocols operate.The text offers a detailed analysis of the significant problems affecting wireless mesh networking, including network scale issues, security, and radio frequency interference, and suggests actual and potential solutions for each pro

  7. Polygon mesh processing

    CERN Document Server

    Botsch, Mario; Pauly, Mark; Alliez, Pierre; Levy, Bruno


    Geometry processing, or mesh processing, is a fast-growing area of research that uses concepts from applied mathematics, computer science, and engineering to design efficient algorithms for the acquisition, reconstruction, analysis, manipulation, simulation, and transmission of complex 3D models. Applications of geometry processing algorithms already cover a wide range of areas from multimedia, entertainment, and classical computer-aided design, to biomedical computing, reverse engineering, and scientific computing. Over the last several years, triangle meshes have become increasingly popular,

  8. Geometrically Consistent Mesh Modification

    KAUST Repository

    Bonito, A.


    A new paradigm of adaptivity is to execute refinement, coarsening, and smoothing of meshes on manifolds with incomplete information about their geometry and yet preserve position and curvature accuracy. We refer to this collectively as geometrically consistent (GC) mesh modification. We discuss the concept of discrete GC, show the failure of naive approaches, and propose and analyze a simple algorithm that is GC and accuracy preserving. © 2010 Society for Industrial and Applied Mathematics.

  9. Risk factors and management of vaginal mesh erosion after pelvic organ prolapse surgery. (United States)

    Cheng, Yung-Wen; Su, Tsung-Hsien; Wang, Hsuan; Huang, Wen-Chu; Lau, Hui-Hsuan


    Mesh erosion is a serious and not uncommon complication in women undergoing vaginal mesh repair. We hypothesized that mesh erosion is associated with the patient's comorbidities, surgical procedures, and mesh material. The aims of this study were to identify the risk factors and optimal management for mesh erosion. All women who underwent vaginal mesh repair from 2004 to 2014 were retrospectively reviewed. Data on patients' characteristics, presenting symptoms, treatment and outcomes were collected from their medical records. A total of 741 women underwent vaginal mesh repairs, of whom 47 had mesh erosion. The median follow-up period was 13 months (range 3-84 months). Another nine patients with mesh erosion were referred form other hospitals. Multivariate analysis revealed that concomitant hysterectomy (odds ratio 27.02, 95% confidence interval 12.35-58.82; p erosion. Of these 56 women, 20 (36%) were successfully treated by conservative management, while 36 (64%) required subsequent surgical revision. Compared with surgery, conservative treatment was successful if the size of the erosion was smaller than 0.5 cm (p erosions after primary revision, but all successfully healed after the second surgery. Concomitant hysterectomy and hypertension were associated with mesh erosion. In the management of mesh erosion, conservative treatment can be tried as the first-line treatment for smaller erosions, while surgical repair for larger erosions. Recurrent erosions could happen and requires repairs several times. Copyright © 2017. Published by Elsevier B.V.

  10. Documentation for MeshKit - Reactor Geometry (&mesh) Generator

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Rajeev [Argonne National Lab. (ANL), Argonne, IL (United States); Mahadevan, Vijay [Argonne National Lab. (ANL), Argonne, IL (United States)


    This report gives documentation for using MeshKit’s Reactor Geometry (and mesh) Generator (RGG) GUI and also briefly documents other algorithms and tools available in MeshKit. RGG is a program designed to aid in modeling and meshing of complex/large hexagonal and rectilinear reactor cores. RGG uses Argonne’s SIGMA interfaces, Qt and VTK to produce an intuitive user interface. By integrating a 3D view of the reactor with the meshing tools and combining them into one user interface, RGG streamlines the task of preparing a simulation mesh and enables real-time feedback that reduces accidental scripting mistakes that could waste hours of meshing. RGG interfaces with MeshKit tools to consolidate the meshing process, meaning that going from model to mesh is as easy as a button click. This report is designed to explain RGG v 2.0 interface and provide users with the knowledge and skills to pilot RGG successfully. Brief documentation of MeshKit source code, tools and other algorithms available are also presented for developers to extend and add new algorithms to MeshKit. RGG tools work in serial and parallel and have been used to model complex reactor core models consisting of conical pins, load pads, several thousands of axially varying material properties of instrumentation pins and other interstices meshes.

  11. Formation of adhesion after intraperitoneal application of TiMesh: experimental study on a rodent model. (United States)

    Delibegovic, Samir; Koluh, Anhel; Cickusic, Elmir; Katica, Muhamed; Mustedanagic, Jasminka; Krupic, Ferid


    After laparoscopic repair of an incisive hernia, intraperitoneal prosthetic mesh, as a foreign material, is a strong stimulus for the development of adhesion, which may be the cause of serious complications. This experimental study compared three different meshes and their ability to prevent the formation of adhesion and shrinkage. Ninety rats were divided randomly into three groups: in Group 1 Proceed mesh was implanted, in Group 2 Ultrapro mesh was implanted, and in Group 3 TiMesh was implanted. Mesh samples were fixed as an intraabdominal mesh in the upper part of the abdomen. Ten animals from each group were sacrificed on days 7, 28 and 60 post-surgery. After opening the abdomen, the formation of adhesion was assessed according to the Surgical Membrane Study Group (SMSG) score, the percentage of shrinkage of the mesh was established and inflammatory reaction scored. The SMSG score for adhesion was statistically significantly higher on all the postoperative days in the Proceed and Ultrapro mesh groups than in the TiMesh group which caused milder inflammatory reaction on 60th day than others meshes. The size of the mesh after 7 days was statistically significantly smaller in the Proceed and Ultrapro groups than in the TiMesh group, but after 60 days it was statistically significantly larger than in the TiMesh group. The least formation of adhesion was noted in the TiMesh group, in which the highest level of shrinkage was noticed after 28 and 60 days. TiMesh has advantages over the other meshes studied, but a larger size mesh may be recommended for intraperitoneal application.

  12. Curved mesh generation and mesh refinement using Lagrangian solid mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Persson, P.-O.; Peraire, J.


    We propose a method for generating well-shaped curved unstructured meshes using a nonlinear elasticity analogy. The geometry of the domain to be meshed is represented as an elastic solid. The undeformed geometry is the initial mesh of linear triangular or tetrahedral elements. The external loading results from prescribing a boundary displacement to be that of the curved geometry, and the final configuration is determined by solving for the equilibrium configuration. The deformations are represented using piecewise polynomials within each element of the original mesh. When the mesh is sufficiently fine to resolve the solid deformation, this method guarantees non-intersecting elements even for highly distorted or anisotropic initial meshes. We describe the method and the solution procedures, and we show a number of examples of two and three dimensional simplex meshes with curved boundaries. We also demonstrate how to use the technique for local refinement of non-curved meshes in the presence of curved boundaries.

  13. In vitro extracellular matrix model to evaluate stroma cell response to transvaginal mesh. (United States)

    Wu, Ming-Ping; Huang, Kuan-Hui; Long, Cheng-Yu; Yang, Chau-Chen; Tong, Yat-Ching


    The use of surgical mesh for female pelvic floor reconstruction has increased in recent years. However, there is paucity of information about the biological responses of host stroma cells to different meshes. This study was aimed to establish an in vitro experimental model to study the micro-environment of extracellular matrix (ECM) with embedded mesh and the stroma cell behaviors to different synthetic meshes. Matrigel multi-cellular co-culture system with embedded mesh was used to evaluate the interaction of stroma cells and synthetic mesh in a simulated ECM environment. Human umbilical vein endothelial cells (HUVEC) and NIH3T3 fibroblasts were inoculated in the system. The established multi-cellular Matrigel co-culture system was used to detect stroma cell recruitment and tube formation ability for different synthetic meshes. HUVEC and NIH3T3 cells were recruited into the mesh interstices and organized into tube-like structures in type I mesh material from Perigee, Marlex and Prolift 24 hr after cell inoculation. On the contrary, there was little recruitment of HUVEC and NIH3T3 cells into the type III mesh of intra-vaginal sling (IVS). The Matrigel multi-cellular co-culture system with embedded mesh offers a useful in vitro model to study the biological behaviors of stroma cells in response to different types of synthetic meshes. The system can help to select ideal mesh candidates before actual implantation into the human body. © 2013 Wiley Periodicals, Inc.

  14. Prosthetic Mesh Repair for Incarcerated Inguinal Hernia

    Directory of Open Access Journals (Sweden)

    Cihad Tatar


    Full Text Available Background: Incarcerated inguinal hernia is a commonly encountered urgent surgical condition, and tension-free repair is a well-established method for the treatment of noncomplicated cases. However, due to the risk of prosthetic material-related infections, the use of mesh in the repair of strangulated or incarcerated hernia has often been subject to debate. Recent studies have demonstrated that biomaterials represent suitable materials for performing urgent hernia repair. Certain studies recommend mesh repair only for cases where no bowel resection is required; other studies, however, recommend mesh repair for patients requiring bowel resection as well. Aim: The aim of this study was to compare the outcomes of different surgical techniques performed for strangulated hernia, and to evaluate the effect of mesh use on postoperative complications. Study Design: Retrospective cross-sectional study. Methods: This retrospective study was performed with 151 patients who had been admitted to our hospital’s emergency department to undergo surgery for a diagnosis of incarcerated inguinal hernia. The patients were divided into two groups based on the applied surgical technique. Group 1 consisted of 112 patients treated with mesh-based repair techniques, while Group 2 consisted of 39 patients treated with tissue repair techniques. Patients in Group 1 were further divided into two sub-groups: one consisting of patients undergoing bowel resection (Group 3, and the other consisting of patients not undergoing bowel resection (Group 4. Results: In Group 1, it was observed that eight (7.14% of the patients had wound infections, while two (1.78% had hematomas, four (3.57% had seromas, and one (0.89% had relapse. In Group 2, one (2.56% of the patients had a wound infection, while three (7.69% had hematomas, one (2.56% had seroma, and none had relapses. There were no statistically significant differences between the two groups with respect to wound infection

  15. Estudo das telas cirúrgicas de polipropileno/poliglecaprone e de polipropileno/polidioxanona/celulose oxidada regenerada na cicatrização de defeito produzido na parede abdominal de ratos Study of surgical meshes of polypropylene/polyglecaprone and polypropylene/polydioxanone/oxidized regenerated cellulose on the healing of defects produced in abdominal wall of rats

    Directory of Open Access Journals (Sweden)

    Marcia Regina Zanello Pundek


    Full Text Available RACIONAL: O uso de telas cirúrgicas para a correção de defeitos da parede abdominal vem ocupando cada vez mais espaço nas operações no mundo todo. OBJETIVO: Estudar duas telas cirúrgicas distintas (Proceed® e Ultrapro® na cicatrização de defeito produzido em parede abdominal de ratos avaliando-se macroscopia, tensiometria e microscopia. MÉTODO: A amostra foi constituída por 32 ratos Wistar, divididos em dois grupos de 16 animais e quatro subgrupos de oito, submetidos à eutanásia com 15 dias e 30 dias para avaliação. As variáveis macroscópicas foram: presença de hematoma nos bordos da sutura da tela cirúrgica na parede abdominal, união entre a tela e a borda da ferida, presença de infecção no sítio cirúrgico, presença de fístulas de vísceras com a tela cirúrgica, presença de aderências dentro da cavidade abdominal e presença de hérnia incisional. Na microscopia avaliaram-se as fases do processo inflamatório da cicatrização, e na tensiometria a força tênsil necessária para ruptura do material. RESULTADOS: A união entre a tela cirúrgica e a borda da ferida foi melhor no subgrupo Ultrapro 15 dias que no Proceed 15 dias; com 30 dias foi igual nos dois subgrupos. Não houve diferença significativa quanto às demais variáveis da macroscopia. Os dois grupos nos dois momentos tiveram a mesma proporção de casos com processo inflamatório crônico, mas houve maior escore de inflamação do Ultrapro 15 dias que do Ultrapro 30 dias. O subgrupo Ultrapro 15 dias mostrou força de ruptura maior que o subgrupo Proceed 15 dias, mas em 30 dias não houve diferença. Ultrapro mostrou força de ruptura igual para os dois momentos, mas Proceed 30 dias mostrou força de ruptura maior que Proceed 15 dias. CONCLUSÃO: As telas são semelhantes nas variáveis analisadas.BACKGROUND: The use of surgical meshes for the repair of abdominal wall defects has been increasing its share in surgeries worldwide. AIM: To study two

  16. Advanced numerical methods in mesh generation and mesh adaptation

    Energy Technology Data Exchange (ETDEWEB)

    Lipnikov, Konstantine [Los Alamos National Laboratory; Danilov, A [MOSCOW, RUSSIA; Vassilevski, Y [MOSCOW, RUSSIA; Agonzal, A [UNIV OF LYON


    Numerical solution of partial differential equations requires appropriate meshes, efficient solvers and robust and reliable error estimates. Generation of high-quality meshes for complex engineering models is a non-trivial task. This task is made more difficult when the mesh has to be adapted to a problem solution. This article is focused on a synergistic approach to the mesh generation and mesh adaptation, where best properties of various mesh generation methods are combined to build efficiently simplicial meshes. First, the advancing front technique (AFT) is combined with the incremental Delaunay triangulation (DT) to build an initial mesh. Second, the metric-based mesh adaptation (MBA) method is employed to improve quality of the generated mesh and/or to adapt it to a problem solution. We demonstrate with numerical experiments that combination of all three methods is required for robust meshing of complex engineering models. The key to successful mesh generation is the high-quality of the triangles in the initial front. We use a black-box technique to improve surface meshes exported from an unattainable CAD system. The initial surface mesh is refined into a shape-regular triangulation which approximates the boundary with the same accuracy as the CAD mesh. The DT method adds robustness to the AFT. The resulting mesh is topologically correct but may contain a few slivers. The MBA uses seven local operations to modify the mesh topology. It improves significantly the mesh quality. The MBA method is also used to adapt the mesh to a problem solution to minimize computational resources required for solving the problem. The MBA has a solid theoretical background. In the first two experiments, we consider the convection-diffusion and elasticity problems. We demonstrate the optimal reduction rate of the discretization error on a sequence of adaptive strongly anisotropic meshes. The key element of the MBA method is construction of a tensor metric from hierarchical edge

  17. Toward An Unstructured Mesh Database (United States)

    Rezaei Mahdiraji, Alireza; Baumann, Peter Peter


    Unstructured meshes are used in several application domains such as earth sciences (e.g., seismology), medicine, oceanography, cli- mate modeling, GIS as approximate representations of physical objects. Meshes subdivide a domain into smaller geometric elements (called cells) which are glued together by incidence relationships. The subdivision of a domain allows computational manipulation of complicated physical structures. For instance, seismologists model earthquakes using elastic wave propagation solvers on hexahedral meshes. The hexahedral con- tains several hundred millions of grid points and millions of hexahedral cells. Each vertex node in the hexahedrals stores a multitude of data fields. To run simulation on such meshes, one needs to iterate over all the cells, iterate over incident cells to a given cell, retrieve coordinates of cells, assign data values to cells, etc. Although meshes are used in many application domains, to the best of our knowledge there is no database vendor that support unstructured mesh features. Currently, the main tool for querying and manipulating unstructured meshes are mesh libraries, e.g., CGAL and GRAL. Mesh li- braries are dedicated libraries which includes mesh algorithms and can be run on mesh representations. The libraries do not scale with dataset size, do not have declarative query language, and need deep C++ knowledge for query implementations. Furthermore, due to high coupling between the implementations and input file structure, the implementations are less reusable and costly to maintain. A dedicated mesh database offers the following advantages: 1) declarative querying, 2) ease of maintenance, 3) hiding mesh storage structure from applications, and 4) transparent query optimization. To design a mesh database, the first challenge is to define a suitable generic data model for unstructured meshes. We proposed ImG-Complexes data model as a generic topological mesh data model which extends incidence graph model to multi

  18. To mesh or not to mesh: a review of pelvic organ reconstructive surgery

    Directory of Open Access Journals (Sweden)

    Dällenbach P


    Full Text Available Patrick Dällenbach Department of Gynecology and Obstetrics, Division of Gynecology, Urogynecology Unit, Geneva University Hospitals, Geneva, Switzerland Abstract: Pelvic organ prolapse (POP is a major health issue with a lifetime risk of undergoing at least one surgical intervention estimated at close to 10%. In the 1990s, the risk of reoperation after primary standard vaginal procedure was estimated to be as high as 30% to 50%. In order to reduce the risk of relapse, gynecological surgeons started to use mesh implants in pelvic organ reconstructive surgery with the emergence of new complications. Recent studies have nevertheless shown that the risk of POP recurrence requiring reoperation is lower than previously estimated, being closer to 10% rather than 30%. The development of mesh surgery – actively promoted by the marketing industry – was tremendous during the past decade, and preceded any studies supporting its benefit for our patients. Randomized trials comparing the use of mesh to native tissue repair in POP surgery have now shown better anatomical but similar functional outcomes, and meshes are associated with more complications, in particular for transvaginal mesh implants. POP is not a life-threatening condition, but a functional problem that impairs quality of life for women. The old adage “primum non nocere” is particularly appropriate when dealing with this condition which requires no treatment when asymptomatic. It is currently admitted that a certain degree of POP is physiological with aging when situated above the landmark of the hymen. Treatment should be individualized and the use of mesh needs to be selective and appropriate. Mesh implants are probably an important tool in pelvic reconstructive surgery, but the ideal implant has yet to be found. The indications for its use still require caution and discernment. This review explores the reasons behind the introduction of mesh augmentation in POP surgery, and aims to

  19. From intraperitoneal onlay mesh repair to preperitoneal onlay mesh repair. (United States)

    Yang, George Pei Cheung


    Laparoscopic repair for ventral and incisional hernias was first reported in the early 1990s. It uses intraperitoneal only mesh placement to achieve a tension-free repair of the hernia. However, in recent years, there has been greater concern about long-term complication involving intraperitoneal mesh placement. Many case reports and case series have found evidence of mesh adhesion, mesh fistulation, and mesh migration into hollow organs including the esophagus, small bowel, and large bowel, resulting in various major acute abdominal events. Subsequent management of these complications may require major surgery that is technically demanding and difficult; in such cases, laparotomy and bowel resection have often been performed. Because of these significant, but not common, adverse events, many surgeons favor open sublay repair for ventral and incisional hernias. Investigators are therefore searching for a laparoscopic approach for ventral and incisional hernias that might overcome the mesh-induced visceral complications seen after intraperitoneal only mesh placement repair. Laparoscopic preperitoneal onlay mesh is one such approach. This article will explore the fundamental of intraperitoneal only mesh placement and its problems, the currently available peritoneal visceral-compatible meshes, and upcoming developments in laparoscopic ventral and incisional hernia repair. The technical details of preperitoneal onlay mesh, as well as its potential advantages and disadvantages, will also be discussed. © 2017 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and John Wiley & Sons Australia, Ltd.

  20. Management of Mesh and Graft Complications in Gynecologic Surgery. (United States)

    This document focuses on the management of complications related to mesh used to correct stress urinary incontinence or pelvic organ prolapse. Persistent vaginal bleeding, vaginal discharge, or recurrent urinary tract infections after mesh placement should prompt an examination and possible further evaluation for exposure or erosion. A careful history and physical examination is essential in the diagnosis of mesh and graft complications. A clear understanding of the location and extent of mesh placement, as well as the patient's symptoms and therapy goals, are necessary to plan treatment approaches. It is important that a treating obstetrician-gynecologist or other gynecologic care provider who seeks to revise or remove implanted mesh be aware of the details of the index procedure. Diagnostic testing for a suspected mesh complication can include cystoscopy, proctoscopy, colonoscopy, or radiologic imaging. These tests should be pursued to answer specific questions related to management. Given the diverse nature of complications related to mesh-augmented pelvic floor surgery, there are no universal recommendations regarding minimum testing. Approaches to management of mesh-related complications in pelvic floor surgery include observation, physical therapy, medications, and surgery. Obstetrician-gynecologists should counsel women who are considering surgical revision or removal of mesh about the complex exchanges that can occur between positive and adverse pelvic floor functions across each additional procedure starting with the device implant. Detailed counseling regarding the risks and benefits of mesh revision or removal surgery is essential and can be conducted most thoroughly by a clinician who has experience performing these procedures. For women who are not symptomatic, there is no role for intervention.


    Energy Technology Data Exchange (ETDEWEB)



    The capability to plot superimposed meshes has been added to MCNP{trademark}. MCNP4C featured a superimposed mesh weight window generator which enabled users to set up geometries without having to subdivide geometric cells for variance reduction. The variance reduction was performed with weight windows on a rectangular or cylindrical mesh superimposed over the physical geometry. Experience with the new capability was favorable but also indicated that a number of enhancements would be very beneficial, particularly a means of visualizing the mesh and its values. The mathematics for plotting the mesh and its values is described here along with a description of other upgrades.

  2. On Optimal Bilinear Quadrilateral Meshes

    Energy Technology Data Exchange (ETDEWEB)

    D' Azevedo, E


    The novelty of this work is in presenting interesting error properties of two types of asymptotically ''optimal'' quadrilateral meshes for bilinear approximation. The first type of mesh has an error equidistributing property where the maximum interpolation error is asymptotically the same over all elements. The second type has faster than expected ''super-convergence'' property for certain saddle-shaped data functions. The ''superconvergent'' mesh may be an order of magnitude more accurate than the error equidistributing mesh. Both types of mesh are generated by a coordinate transformation of a regular mesh of squares. The coordinate transformation is derived by interpreting the Hessian matrix of a data function as a metric tensor. The insights in this work may have application in mesh design near corner or point singularities.

  3. [Implants for genital prolapse : Pro mesh surgery]. (United States)

    Neymeyer, J; Moldovan, D-E; Kornienko, K; Miller, K; Weichert, A


    There has been an overall increase in pelvic organ prolapse due to demographic changes (increased life expectancy). Increasing sociocultural demands of women require treatments that are more effective with methods that are more successful. In the treatment of pelvic floor insufficiency and uterovaginal prolapse, pelvic floor reconstructions with mesh implants have proven to be superior to conventional methods such as the classic colporrhaphy, reconstructions with biomaterial, and native tissue repair in appropriately selected patients and when applying exact operation techniques, especially because of good long-term results and low recurrence rates. When making a systematic therapy plan, one should adhere to certain steps, for example, a pelvic floor reconstruction should be undertaken before performing the corrective procedure for incontinence. The approach, if vaginal, laparoscopic, or abdominal should be chosen wisely, taking into consideration the required space of action, in such a way that none or only minimal collateral damage related to the operation occurs. The use of instrumental suturing techniques and operation robots are advantageous in the case of difficult approaches and limited anatomical spaces. In principle, the surgeon who implants meshes should be able to explant them! The surgical concept of mesh-related interventions in the pelvis must meet established rules. "Implant as little mesh as possible and only as much suitable (!) mesh as absolutely necessary!" In the case of apical direct fixations, a therapeutically relevant target variable is the elevation angle of vagina (EAV). Established anatomical fixation points are preferable. A safe distance between implants and vulnerable tissue is to be maintained. Mesh-based prolapse repairs are indicated in recurrences, in primary situations, in combined defects of the anterior compartment, in central defects of multimorbid and elderly patients, and above all, when organ preservation is wanted


    Directory of Open Access Journals (Sweden)

    Marijan Lužnik


    Full Text Available Background. Use of alloplastic mesh implantates allow a new urogynecologycal surgical techniques achieve a marked improvement in pelvic organ static and pelvic floor function with minimally invasive needle transvaginal intervention like an anterior transobturator mesh (ATOM and a posterior ischiorectal mesh (PIRM procedures. Methods. In three years, between April 2006 and May 2009, we performed one hundred and eightyfour operative corrections of female pelvic organ prolapse (POP and pelvic floor dysfunction (PFD with mesh implantates. The eighty-three patients with surgical procedure TVT-O or Monarc as solo intervention indicated by stress urinary incontinence without POP, are not included in this number. In 97 % of mesh operations, Gynemesh 10 × 15 cm was used. For correction of anterior vaginal prolapse with ATOM procedure, Gynemesh was individually trimmed in mesh with 6 free arms for tension-free transobturator application and tension-free apical collar. IVS (Intravaginal sling 04 Tunneller (Tyco needle system was used for transobturator application of 6 arms through 4 dermal incisions (2 on right and 2 on left. Minimal anterior median colpotomy was made in two separate parts. For correction of posterior vaginal prolapse with PIRM procedure Gynemesh was trimmed in mesh with 4 free arms and tension-free collar. Two ischiorectal long arms for tension-free application through fossa ischiorectale – right and left, and two short arms for perineal body also on both sides. IVS 02 Tunneller (Tyco needle system was used for tension-free application of 4 arms through 4 dermal incisions (2 on right and 2 on left in PIRM. Results. All 184 procedures were performed relatively safely. In 9 cases of ATOM we had perforation of bladder, in 5 by application of anterior needle, in 3 by application of posterior needle and in one case with pincette when collar was inserted in lateral vesico – vaginal space. In 2 cases of PIRM we had perforation of rectum

  5. A Newly‑devised Technique for the Fixation of Mesh Skin Graft

    African Journals Online (AJOL)

    cyanoacrylate (Dermabond; Ethicon), which was termed “Dendritic bonding.” This technique exhibits several advantages over surgical stapling and suturing with absorbable sutures. Key words: Dermabond, mesh, octyl-2-cyanoacrylate, skin graft.

  6. Corset neophallic musculoplasty with a mesh endoprosthesis

    Directory of Open Access Journals (Sweden)

    V. V. Mikhailichenko


    Full Text Available During thoracodorsal flap phalloplasty, recovered contractility of the muscular base of the neophallus may lead to its shortening that impedes introjection.To eliminate deformity and shortening of the neophallus, the authors propose the procedure of corset plasty of its muscle, which differs in that the alloplastic material – esfil mesh endoprosthesis, is used as a corset instead of fascia latum of the hip. The proposed procedure reduces surgical trauma, improves the functional characteristics of the neophallus, and accelerates sexual rehabilitation.

  7. Corset neophallic musculoplasty with a mesh endoprosthesis

    Directory of Open Access Journals (Sweden)

    V. V. Mikhailichenko


    Full Text Available During thoracodorsal flap phalloplasty, recovered contractility of the muscular base of the neophallus may lead to its shortening that impedes introjection.To eliminate deformity and shortening of the neophallus, the authors propose the procedure of corset plasty of its muscle, which differs in that the alloplastic material – esfil mesh endoprosthesis, is used as a corset instead of fascia latum of the hip. The proposed procedure reduces surgical trauma, improves the functional characteristics of the neophallus, and accelerates sexual rehabilitation.

  8. Notes on the Mesh Handler and Mesh Data Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Yong; Park, Chan Eok [Korea Power Engineering Company, Daejeon (Korea, Republic of)


    At the outset of the development of the thermal-hydraulic code (THC), efforts have been made to utilize the recent technology of the computational fluid dynamics. Among many of them, the unstructured mesh approach was adopted to alleviate the restriction of the grid handling system. As a natural consequence, a mesh handler (MH) has been developed to manipulate the complex mesh data from the mesh generator. The mesh generator, Gambit, was chosen at the beginning of the development of the code. But a new mesh generator, Pointwise, was introduced to get more flexible mesh generation capability. An open source code, Paraview, was chosen as a post processor, which can handle unstructured as well as structured mesh data. Overall data processing system for THC is shown in Figure-1. There are various file formats to save the mesh data in the permanent storage media. A couple of dozen of file formats are found even in the above mentioned programs. A competent mesh handler should have the capability to import or export mesh data as many as possible formats. But, in reality, there are two aspects that make it difficult to achieve the competence. The first aspect to consider is the time and efforts to program the interface code. And the second aspect, which is even more difficult one, is the fact that many mesh data file formats are proprietary information. In this paper, some experience of the development of the format conversion programs will be presented. File formats involved are Gambit neutral format, Ansys-CFX grid file format, VTK legacy file format, Nastran format and CGNS.

  9. Notes on the Mesh Handler and Mesh Data Conversion

    International Nuclear Information System (INIS)

    Lee, Sang Yong; Park, Chan Eok


    At the outset of the development of the thermal-hydraulic code (THC), efforts have been made to utilize the recent technology of the computational fluid dynamics. Among many of them, the unstructured mesh approach was adopted to alleviate the restriction of the grid handling system. As a natural consequence, a mesh handler (MH) has been developed to manipulate the complex mesh data from the mesh generator. The mesh generator, Gambit, was chosen at the beginning of the development of the code. But a new mesh generator, Pointwise, was introduced to get more flexible mesh generation capability. An open source code, Paraview, was chosen as a post processor, which can handle unstructured as well as structured mesh data. Overall data processing system for THC is shown in Figure-1. There are various file formats to save the mesh data in the permanent storage media. A couple of dozen of file formats are found even in the above mentioned programs. A competent mesh handler should have the capability to import or export mesh data as many as possible formats. But, in reality, there are two aspects that make it difficult to achieve the competence. The first aspect to consider is the time and efforts to program the interface code. And the second aspect, which is even more difficult one, is the fact that many mesh data file formats are proprietary information. In this paper, some experience of the development of the format conversion programs will be presented. File formats involved are Gambit neutral format, Ansys-CFX grid file format, VTK legacy file format, Nastran format and CGNS

  10. The effect of thymoquinone coating on adhesive properties of polypropylene mesh. (United States)

    Aydin, Oktay; Aydinuraz, Kuzey; Agalar, Fatih; Sahiner, I Tayfun; Agalar, Canan; Bayram, Cem; Denkbas, Emir Baki; Atasoy, Pinar


    An incisional hernia is a common complication following abdominal surgery. Polypropylene mesh is frequently used in the repair of such defects and has nearly become the standard surgical treatment modality. Though they are very effective in reducing recurrence, mesh materials exhibit a strong stimulating effect for intraabdominal adhesion. The thymoquinone (TQ) extracted from Nigella sativa seeds has potential medical properties. TQ has anti-inflammatory, antioxidant and antibacterial properties. The aim of this study is to coat polypropylene mesh with TQ in order to investigate the effect of surface modification on intraabdominal adhesions. TQ-coated polypropylene mesh material was tested for cytotoxicity, contact angle, surface spectroscopy, TQ content, sterility, and electron microscopic surface properties. An experimental incisional hernia model was created in study groups, each consisting of 12 female Wistar rats. The defect was closed with uncoated mesh in control group, with polylactic acid (PLA) coated mesh and PLA-TQ coated mesh in study groups. Adhesion scores and histopathologic properties were evaluated after sacrifice on postoperative 21th day. Granuloma formation, lymphocyte and polymorphonuclear leukocyte infiltration, histiocyte fibroblast and giant cell formation, capillary infiltration, collagen content were significantly reduced in the PLA-TQ coated mesh group (p < 0.05). Though not statistically significant, likely due to the limited number of study animals, adhesion formation was also reduced in the PLA-TQ coated mesh group (p: 0.067). TQ coated mesh is shown to reduce adhesion formation and TQ is a promising coating material for mesh surface modification.

  11. What is the evidence for the use of biologic or biosynthetic meshes in abdominal wall reconstruction? (United States)

    Köckerling, F; Alam, N N; Antoniou, S A; Daniels, I R; Famiglietti, F; Fortelny, R H; Heiss, M M; Kallinowski, F; Kyle-Leinhase, I; Mayer, F; Miserez, M; Montgomery, A; Morales-Conde, S; Muysoms, F; Narang, S K; Petter-Puchner, A; Reinpold, W; Scheuerlein, H; Smietanski, M; Stechemesser, B; Strey, C; Woeste, G; Smart, N J


    Although many surgeons have adopted the use of biologic and biosynthetic meshes in complex abdominal wall hernia repair, others have questioned the use of these products. Criticism is addressed in several review articles on the poor standard of studies reporting on the use of biologic meshes for different abdominal wall repairs. The aim of this consensus review is to conduct an evidence-based analysis of the efficacy of biologic and biosynthetic meshes in predefined clinical situations. A European working group, "BioMesh Study Group", composed of invited surgeons with a special interest in surgical meshes, formulated key questions, and forwarded them for processing in subgroups. In January 2016, a workshop was held in Berlin where the findings were presented, discussed, and voted on for consensus. Findings were set out in writing by the subgroups followed by consensus being reached. For the review, 114 studies and background analyses were used. The cumulative data regarding biologic mesh under contaminated conditions do not support the claim that it is better than synthetic mesh. Biologic mesh use should be avoided when bridging is needed. In inguinal hernia repair biologic and biosynthetic meshes do not have a clear advantage over the synthetic meshes. For prevention of incisional or parastomal hernias, there is no evidence to support the use of biologic/biosynthetic meshes. In complex abdominal wall hernia repairs (incarcerated hernia, parastomal hernia, infected mesh, open abdomen, enterocutaneous fistula, and component separation technique), biologic and biosynthetic meshes do not provide a superior alternative to synthetic meshes. The routine use of biologic and biosynthetic meshes cannot be recommended.

  12. Evidence for replacement of an infected synthetic by a biological mesh in abdominal wall hernia repair

    Directory of Open Access Journals (Sweden)

    Agneta eMontgomery


    Full Text Available The incidence of deep infection using a synthetic mesh in inguinal hernia repair is low and reported to be well below 1%. This is in contrast to incisional hernia surgery where the reported incidence is 3% respective 13% comparing laparoscopic to open mesh repair reported in a Cochrane review. Main risk factors were long operation time, surgical site contamination and early wound complications. An infected mesh can be preserved using conservative treatment were negative pressure wound therapy (VAC® could play an important role. If strategy fails, the mesh needs to be removed. This review aims to look at evidence for situations were a biological mesh would work as a replacement of a removed infected synthetic mesh. Material and MethodsA literature search of the Medline database was performed using the PubMed search engine. Twenty publications were found relevant for this review.ResultsFor studies reviewed three options are presented: removal of the infected synthetic mesh alone, replacement with either a new synthetic or a new biological mesh. Operations were all performed at specialist centers. Removal of the mesh alone was an option limited to inguinal hernias. In ventral/incisional hernias the use of a biological mesh for replacement resulted in a very high recurrence rate, if bridging was required. Either a synthetic or a biological mesh seems to work as a replacement when fascial closure can be achieved. Evidence is though very low. ConclusionWhen required, either a synthetic or a biological meshes seems to work as a replacement for an infected synthetic mesh if the defect can be closed. It is however not recommended to use a biological mesh for bridging. Mesh replacement surgery is demanding and is recommended to be performed in a specialist center.

  13. An Adaptive Mesh Algorithm: Mesh Structure and Generation

    Energy Technology Data Exchange (ETDEWEB)

    Scannapieco, Anthony J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    The purpose of Adaptive Mesh Refinement is to minimize spatial errors over the computational space not to minimize the number of computational elements. The additional result of the technique is that it may reduce the number of computational elements needed to retain a given level of spatial accuracy. Adaptive mesh refinement is a computational technique used to dynamically select, over a region of space, a set of computational elements designed to minimize spatial error in the computational model of a physical process. The fundamental idea is to increase the mesh resolution in regions where the physical variables are represented by a broad spectrum of modes in k-space, hence increasing the effective global spectral coverage of those physical variables. In addition, the selection of the spatially distributed elements is done dynamically by cyclically adjusting the mesh to follow the spectral evolution of the system. Over the years three types of AMR schemes have evolved; block, patch and locally refined AMR. In block and patch AMR logical blocks of various grid sizes are overlaid to span the physical space of interest, whereas in locally refined AMR no logical blocks are employed but locally nested mesh levels are used to span the physical space. The distinction between block and patch AMR is that in block AMR the original blocks refine and coarsen entirely in time, whereas in patch AMR the patches change location and zone size with time. The type of AMR described herein is a locally refi ned AMR. In the algorithm described, at any point in physical space only one zone exists at whatever level of mesh that is appropriate for that physical location. The dynamic creation of a locally refi ned computational mesh is made practical by a judicious selection of mesh rules. With these rules the mesh is evolved via a mesh potential designed to concentrate the nest mesh in regions where the physics is modally dense, and coarsen zones in regions where the physics is modally

  14. A comparative study of onlay and retrorectus mesh placement in incisional hernia repair

    Directory of Open Access Journals (Sweden)

    Kundan Kharde


    Full Text Available Introduction: Incisional hernia after abdominal surgery is a well-known complication and the incidence of incisional hernias continues to be 2-11% after laparotomy. The repair of incisional hernia has always been a challenge to the surgeon. Various operative techniques for the repair of incisional hernia are in practice; however, the management is not standardized. The retro-rectus mesh placement or the sub-lay technique, popularized by Rives and Stoppa in Europe, has been reported to be quite effective, with low recurrence rates (0-23% and minimal complications. Aims and Objective: The purpose of this study was to compare the traditional on-lay mesh and retro-rectus mesh placement in incisional hernia repairs in terms of time taken for surgery, early complications (wound infections, Mesh extrusion, and Delayed complications (Recurrence. Materials and Methods: This is a prospective study which was conducted in the surgical department of our hospital. A total of 50 cases were included in this study. Of these cases, 25 cases were operated by the on-lay mesh method and 25 by retro-rectus mesh placement. Only the patients with midline hernias up to 10 cm in diameter were included in the study. Result: The operative time for retro-rectus mesh placement was insignificantly higher than that of on-lay mesh repair, whereas, complications like superficial Surgical site infection SSI were identical in both the study groups, but deep SSI leading to infection of mesh was higher in on-lay mesh repair. The recurrence rate was found to be 4% in on-lay mesh repair and 0% in retro-rectus mesh repair. Conclusion: The follow-up period in this study was 6months; hence, late recurrences were not taken into account. However, the low rate of local complications and the low recurrence rate indicate that retro-rectus mesh repair has an advantage over traditional on-lay repair.

  15. Surface meshing with curvature convergence

    KAUST Repository

    Li, Huibin


    Surface meshing plays a fundamental role in graphics and visualization. Many geometric processing tasks involve solving geometric PDEs on meshes. The numerical stability, convergence rates and approximation errors are largely determined by the mesh qualities. In practice, Delaunay refinement algorithms offer satisfactory solutions to high quality mesh generations. The theoretical proofs for volume based and surface based Delaunay refinement algorithms have been established, but those for conformal parameterization based ones remain wide open. This work focuses on the curvature measure convergence for the conformal parameterization based Delaunay refinement algorithms. Given a metric surface, the proposed approach triangulates its conformal uniformization domain by the planar Delaunay refinement algorithms, and produces a high quality mesh. We give explicit estimates for the Hausdorff distance, the normal deviation, and the differences in curvature measures between the surface and the mesh. In contrast to the conventional results based on volumetric Delaunay refinement, our stronger estimates are independent of the mesh structure and directly guarantee the convergence of curvature measures. Meanwhile, our result on Gaussian curvature measure is intrinsic to the Riemannian metric and independent of the embedding. In practice, our meshing algorithm is much easier to implement and much more efficient. The experimental results verified our theoretical results and demonstrated the efficiency of the meshing algorithm. © 2014 IEEE.

  16. Quadrilateral finite element mesh coarsening (United States)

    Staten, Matthew L; Dewey, Mark W; Benzley, Steven E


    Techniques for coarsening a quadrilateral mesh are described. These techniques include identifying a coarsening region within the quadrilateral mesh to be coarsened. Quadrilateral elements along a path through the coarsening region are removed. Node pairs along opposite sides of the path are identified. The node pairs along the path are then merged to collapse the path.

  17. Fog-harvesting Mesh Surfaces (United States)

    Park, Kyoo-Chul; Chhatre, Shreerang S.; Srinivasan, Siddarth; Cohen, Robert E.; McKinley, Gareth H.


    Fog represents a large, untapped source of potable water, especially in arid climates. Various plants and animals use morphological as well as chemical features on their surfaces to harvest this precious resource. In this work, we investigate the influence of surface wettability, structural length scale, and relative openness of the weave on the fog harvesting ability of mesh surfaces. We choose simple woven meshes as a canonical family of model permeable surfaces due to the ability to systematically vary periodicity, porosity, mechanical robustness and ease of fabrication. We measure the fog collecting capacity of a set of meshes with a directed aqueous aerosol stream to simulate a natural foggy environment. Further, we strive to develop and test appropriate scalings and correlations that quantify the collection of water on the mesh surfaces. These design rules can be deployed as an a priori design chart for designing optimal performance meshes for given environmental/operating conditions.

  18. Ocean modeling on unstructured meshes (United States)

    Danilov, S.


    Unstructured meshes are common in coastal modeling, but still rarely used for modeling the large-scale ocean circulation. Existing and new projects aim at changing this situation by proposing models enabling a regional focus (multiresolution) in global setups, without nesting and open boundaries. Among them, finite-volume models using the C-grid discretization on Voronoi-centroidal meshes or cell-vertex quasi-B-grid discretization on triangular meshes work well and offer the multiresolution functionality at a price of being 2 to 4 times slower per degree of freedom than structured-mesh models. This is already sufficient for many practical tasks and will be further improved as the number of vertical layers is increased. Approaches based on the finite-element method, both used or proposed, are as a rule slower at present. Most of staggered discretizations on triangular or Voronoi meshes allow spurious modes which are difficult to filter on unstructured meshes. The ongoing research seeks how to handle them and explores new approaches where such modes are absent. Issues of numerical efficiency and accurate transport schemes are still important, and the question on parameterizations for multiresolution meshes is hardly explored at all. The review summarizes recent developments the main practical result of which is the emergence of multiresolution models for simulating large-scale ocean circulation.

  19. Early Wound Morbidity after Open Ventral Hernia Repair with Biosynthetic or Polypropylene Mesh. (United States)

    Sahoo, Sambit; Haskins, Ivy N; Huang, Li-Ching; Krpata, David M; Derwin, Kathleen A; Poulose, Benjamin K; Rosen, Michael J


    Recently introduced slow-resorbing biosynthetic and non-resorbing macroporous polypropylene meshes are being used in hernias with clean-contaminated and contaminated wounds. However, information about the use of biosynthetic meshes and their outcomes compared with polypropylene meshes in clean-contaminated and contaminated cases is lacking. Here we evaluate the use of biosynthetic mesh and polypropylene mesh in elective open ventral hernia repair (OVHR) and investigate differences in early wound morbidity after OVHR within clean-contaminated and contaminated cases. All elective, OVHR with biosynthetic mesh or uncoated polypropylene mesh from January 2013 through October 2016 were identified within the Americas Hernia Society Quality Collaborative. Association of mesh type with 30-day wound events in clean-contaminated or contaminated wounds was investigated using a 1:3 propensity-matched analysis. Biosynthetic meshes were used in 8.5% (175 of 2,051) of elective OVHR, with the majority (57.1%) used in low-risk or comorbid clean cases. Propensity-matched analysis in clean-contaminated and contaminated cases showed no significant difference between biosynthetic mesh and polypropylene mesh groups for 30-day surgical site occurrences (20.7% vs 16.7%; p = 0.49) or unplanned readmission (13.8% vs 9.8%; p = 0.4). However, surgical site infections (22.4% vs 10.9%; p = 0.03), surgical site occurrences requiring procedural intervention (24.1% vs 13.2%; p = 0.049), and reoperation rates (13.8% vs 4.0%; p = 0.009) were significantly higher in the biosynthetic group. Biosynthetic mesh appears to have higher rates of 30-day wound morbidity compared with polypropylene mesh in elective OVHR with clean-contaminated or contaminated wounds. Additional post-market analysis is needed to provide evidence defining best mesh choices, location, and surgical technique for repairing contaminated ventral hernias. Copyright © 2017 American College of Surgeons. Published by Elsevier Inc

  20. Mesh Adaptation and Shape Optimization on Unstructured Meshes, Phase I (United States)

    National Aeronautics and Space Administration — In this SBIR CRM proposes to implement the entropy adjoint method for solution adaptive mesh refinement into the Loci/CHEM unstructured flow solver. The scheme will...

  1. Mersiline mesh in premaxillary augmentation. (United States)

    Foda, Hossam M T


    Premaxillary retrusion may distort the aesthetic appearance of the columella, lip, and nasal tip. This defect is characteristically seen in, but not limited to, patients with cleft lip nasal deformity. This study investigated 60 patients presenting with premaxillary deficiencies in which Mersiline mesh was used to augment the premaxilla. All the cases had surgery using the external rhinoplasty technique. Two methods of augmentation with Mersiline mesh were used: the Mersiline roll technique, for the cases with central symmetric deficiencies, and the Mersiline packing technique, for the cases with asymmetric deficiencies. Premaxillary augmentation with Mersiline mesh proved to be simple technically, easy to perform, and not associated with any complications. Periodic follow-up evaluation for a mean period of 32 months (range, 12-98 months) showed that an adequate degree of premaxillary augmentation was maintained with no clinically detectable resorption of the mesh implant.

  2. Experimental study of the characteristics of a novel mesh suture. (United States)

    Dumanian, G A; Tulaimat, A; Dumanian, Z P


    The failure of sutures to maintain tissue in apposition is well characterized in hernia repairs. A mesh suture designed to facilitate tissue integration into and around the filaments may improve tissue hold and decrease suture pull-through. In vitro, the sutures were compared for resistance to pull-through in ballistics gel. In vivo, closure of midline laparotomy incisions was done with both sutures in 11 female pigs. Tissue segments were subsequently subjected to mechanical and histological testing. The mesh suture had tensile characteristics nearly identical to those of 0-polypropylene suture. Mesh suture demonstrated greater resistance to pull-through than standard suture (mean(s.d.) 4.27(0.42) versus 2.23(0.48) N; P tension closures. A new mesh suture design with a flexible macroporous outer wall and a hollow core allows the tissues to grow into the suture, improving early wound strength and decreasing suture pull-through. This technology may dramatically increase the reliability of high-tension closures, thereby preventing incisional hernia after laparotomy. As suture pull-through is a problem relevant to all surgical disciplines, numerous additional indications are envisioned with mesh suture formulations of different physical properties and materials. © 2015 The Authors. BJS published by John Wiley & Sons Ltd on behalf of BJS Society Ltd.


    Directory of Open Access Journals (Sweden)

    Vlasov Aleksandr Nikolaevich


    Decomposition is performed in a constructive way and, as option, it involves meshless representation. Further, this mapping method is used to generate the calculation mesh. In this paper, the authors analyze different cases of mapping onto simply connected and bi-connected canonical domains. They represent forward and backward mapping techniques. Their potential application for generation of nonuniform meshes within the framework of the asymptotic homogenization theory is also performed to assess and project effective characteristics of heterogeneous materials (composites.

  4. Method and system for mesh network embedded devices (United States)

    Wang, Ray (Inventor)


    A method and system for managing mesh network devices. A mesh network device with integrated features creates an N-way mesh network with a full mesh network topology or a partial mesh network topology.

  5. The effect of thymoquinone coating on adhesive properties of polypropylene mesh


    Aydin, Oktay; Aydinuraz, Kuzey; Agalar, Fatih; Sahiner, I. Tayfun; Agalar, Canan; Bayram, Cem; Denkbas, Emir Baki; Atasoy, Pinar


    Background An incisional hernia is a common complication following abdominal surgery. Polypropylene mesh is frequently used in the repair of such defects and has nearly become the standard surgical treatment modality. Though they are very effective in reducing recurrence, mesh materials exhibit a strong stimulating effect for intraabdominal adhesion. The thymoquinone (TQ) extracted from Nigella sativa seeds has potential medical properties. TQ has anti-inflammatory, antioxidant and antibacter...

  6. Comparative analysis of biologic versus synthetic mesh outcomes in contaminated hernia repairs. (United States)

    Majumder, Arnab; Winder, Joshua S; Wen, Yuxiang; Pauli, Eric M; Belyansky, Igor; Novitsky, Yuri W


    Contaminated operative fields pose significant challenges for surgeons performing ventral hernia repair. Although biologic meshes have been utilized increasingly in these fields, recent evidence suggests that synthetic meshes represent a viable option. We analyzed the outcomes of biologic and synthetic mesh utilized in patients undergoing major ventral hernia repair in clean-contaminated/contaminated fields. We conducted a multicenter, retrospective review of patients undergoing open ventral hernia repair in clean-contaminated/contaminated fields using biologic or synthetic mesh. Patient and hernia details were characterized. Primary outcomes included 90-day surgical site event, surgical site infection, and hernia recurrence. A total of 126 patients undergoing major ventral hernia repair in clean-contaminated/contaminated fields (69 biologic and 57 synthetic meshes) were analyzed. Groups were similar in both patient and hernia characteristics. There were 13 (22.8%) surgical site events in the synthetic cohort compared to 29 (42.0%) in the biologic cohort, P = .024. Similarly, surgical site infections were less frequent in the synthetic group, with 7 (12.3%) vs 22 (31.9%), P = .01. With a mean follow-up of 20 months, there were more recurrences in the biologic group: 15 (26.3%) vs 4 (8.9%) in the synthetic group, P = .039. The choice of mesh for clean-contaminated/contaminated ventral hernia repair remains debatable. We demonstrated that using synthetic sublay mesh resulted in a significantly lower wound morbidity and more durable outcomes versus a similar cohort of biologic repairs. This is likely secondary to improved bacterial clearance and faster integration of macroporous synthetics. Overall, our findings not only support suitability of synthetic mesh in contaminated settings but also challenge the purported advantage of biologics in clean-contaminated/contaminated ventral hernia repairs. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Preparation and Characterization of Antibacterial Polypropylene Meshes with Covalently Incorporated β-Cyclodextrins and Captured Antimicrobial Agent for Hernia Repair

    Directory of Open Access Journals (Sweden)

    Noor Sanbhal


    Full Text Available Polypropylene (PP light weight meshes are commonly used as hernioplasty implants. Nevertheless, the growth of bacteria within textile knitted mesh intersections can occur after surgical mesh implantation, causing infections. Thus, bacterial reproduction has to be stopped in the very early stage of mesh implantation. Herein, novel antimicrobial PP meshes grafted with β-CD and complexes with triclosan were prepared for mesh infection prevention. Initially, PP mesh surfaces were functionalized with suitable cold oxygen plasma. Then, hexamethylene diisocyanate (HDI was successfully grafted on the plasma-activated PP surfaces. Afterwards, β-CD was connected with the already HDI reacted PP meshes and triclosan, serving as a model antimicrobial agent, was loaded into the cyclodextrin (CD cavity for desired antibacterial functions. The hydrophobic interior and hydrophilic exterior of β-CD are well suited to form complexes with hydrophobic host guest molecules. Thus, the prepared PP mesh samples, CD-TCL-2 and CD-TCL-6 demonstrated excellent antibacterial properties against Staphylococcus aureus and Escherichia coli that were sustained up to 11 and 13 days, respectively. The surfaces of chemically modified PP meshes showed dramatically reduced water contact angles. Moreover, X-ray diffractometer (XRD, differential scanning calorimeter (DSC, and Thermogravimetric (TGA evidenced that there was no significant effect of grafted hexamethylene diisocyanate (HDI and CD on the structural and thermal properties of the PP meshes.

  8. Abortion - surgical (United States)

    Suction curettage; Surgical abortion; Elective abortion - surgical; Therapeutic abortion - surgical ... Surgical abortion involves dilating the opening to the uterus (cervix) and placing a small suction tube into the uterus. ...

  9. Connectivity editing for quadrilateral meshes

    KAUST Repository

    Peng, Chihan


    We propose new connectivity editing operations for quadrilateral meshes with the unique ability to explicitly control the location, orientation, type, and number of the irregular vertices (valence not equal to four) in the mesh while preserving sharp edges. We provide theoretical analysis on what editing operations are possible and impossible and introduce three fundamental operations to move and re-orient a pair of irregular vertices. We argue that our editing operations are fundamental, because they only change the quad mesh in the smallest possible region and involve the fewest irregular vertices (i.e., two). The irregular vertex movement operations are supplemented by operations for the splitting, merging, canceling, and aligning of irregular vertices. We explain how the proposed high-level operations are realized through graph-level editing operations such as quad collapses, edge flips, and edge splits. The utility of these mesh editing operations are demonstrated by improving the connectivity of quad meshes generated from state-of-art quadrangulation techniques.

  10. Cache-Oblivious Mesh Layouts

    International Nuclear Information System (INIS)

    Yoon, S; Lindstrom, P; Pascucci, V; Manocha, D


    We present a novel method for computing cache-oblivious layouts of large meshes that improve the performance of interactive visualization and geometric processing algorithms. Given that the mesh is accessed in a reasonably coherent manner, we assume no particular data access patterns or cache parameters of the memory hierarchy involved in the computation. Furthermore, our formulation extends directly to computing layouts of multi-resolution and bounding volume hierarchies of large meshes. We develop a simple and practical cache-oblivious metric for estimating cache misses. Computing a coherent mesh layout is reduced to a combinatorial optimization problem. We designed and implemented an out-of-core multilevel minimization algorithm and tested its performance on unstructured meshes composed of tens to hundreds of millions of triangles. Our layouts can significantly reduce the number of cache misses. We have observed 2-20 times speedups in view-dependent rendering, collision detection, and isocontour extraction without any modification of the algorithms or runtime applications

  11. Connectivity editing for quadrilateral meshes

    KAUST Repository

    Peng, Chihan


    We propose new connectivity editing operations for quadrilateral meshes with the unique ability to explicitly control the location, orientation, type, and number of the irregular vertices (valence not equal to four) in the mesh while preserving sharp edges. We provide theoretical analysis on what editing operations are possible and impossible and introduce three fundamental operations to move and re-orient a pair of irregular vertices. We argue that our editing operations are fundamental, because they only change the quad mesh in the smallest possible region and involve the fewest irregular vertices (i.e., two). The irregular vertex movement operations are supplemented by operations for the splitting, merging, canceling, and aligning of irregular vertices. We explain how the proposed highlevel operations are realized through graph-level editing operations such as quad collapses, edge flips, and edge splits. The utility of these mesh editing operations are demonstrated by improving the connectivity of quad meshes generated from state-of-art quadrangulation techniques. © 2011 ACM.

  12. Heterogeneous meshing and biomechanical modeling of human spine. (United States)

    Teo, J C M; Chui, C K; Wang, Z L; Ong, S H; Yan, C H; Wang, S C; Wong, H K; Teoh, S H


    We aim to develop a patient-specific biomechanical model of human spine for the purpose of surgical training and planning. In this paper, we describe the development of a finite-element model of the spine from the VHD Male Data. The finite-element spine model comprises volumetric elements suitable for deformation and other finite-element analysis using ABAQUS. The mesh generation solution accepts segmented radiological slices as input, and outputs three-dimensional (3D) volumetric finite element meshes that are ABAQUS compliant. The proposed mesh generation method first uses a grid plane to divide the contours of the anatomical boundaries and its inclusions into discrete meshes. A grid frame is then built to connect the grid planes between any two adjacent planes using a novel scheme. The meshes produced consist of brick elements in the interior of the contours and with tetrahedral and wedge elements at the boundaries. The nodal points are classified according to their materials and hence, elements can be assigned different properties. The resultant spine model comprises a detailed model of the 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, and S1. Each of the vertebrae and intervertebral disc has between 1200 and 6000 elements, and approximately 1200 elements, respectively. The accuracy of the resultant VHD finite element spine model was good based on visual comparison of volume-rendered images of the original CT data, and has been used in a computational analysis involving needle insertion and static deformation. We also compared the mesh generated using our method against two automatically generated models; one consists of purely tetrahedral elements and the other hexahedral elements.

  13. Issues in adaptive mesh refinement

    Energy Technology Data Exchange (ETDEWEB)

    Dai, William Wenlong [Los Alamos National Laboratory


    In this paper, we present an approach for a patch-based adaptive mesh refinement (AMR) for multi-physics simulations. The approach consists of clustering, symmetry preserving, mesh continuity, flux correction, communications, and management of patches. Among the special features of this patch-based AMR are symmetry preserving, efficiency of refinement, special implementation offlux correction, and patch management in parallel computing environments. Here, higher efficiency of refinement means less unnecessarily refined cells for a given set of cells to be refined. To demonstrate the capability of the AMR framework, hydrodynamics simulations with many levels of refinement are shown in both two- and three-dimensions.

  14. Deriving DICOM surgical extensions from surgical workflows (United States)

    Burgert, O.; Neumuth, T.; Gessat, M.; Jacobs, S.; Lemke, H. U.


    The generation, storage, transfer, and representation of image data in radiology are standardized by DICOM. To cover the needs of image guided surgery or computer assisted surgery in general one needs to handle patient information besides image data. A large number of objects must be defined in DICOM to address the needs of surgery. We propose an analysis process based on Surgical Workflows that helps to identify these objects together with use cases and requirements motivating for their specification. As the first result we confirmed the need for the specification of representation and transfer of geometric models. The analysis of Surgical Workflows has shown that geometric models are widely used to represent planned procedure steps, surgical tools, anatomical structures, or prosthesis in the context of surgical planning, image guided surgery, augmented reality, and simulation. By now, the models are stored and transferred in several file formats bare of contextual information. The standardization of data types including contextual information and specifications for handling of geometric models allows a broader usage of such models. This paper explains the specification process leading to Geometry Mesh Service Object Pair classes. This process can be a template for the definition of further DICOM classes.

  15. ECM hydrogel coating mitigates the chronic inflammatory response to polypropylene mesh. (United States)

    Faulk, Denver M; Londono, Ricardo; Wolf, Matthew T; Ranallo, Christian A; Carruthers, Christopher A; Wildemann, Justin D; Dearth, Christopher L; Badylak, Stephen F


    Polypropylene has been used as a surgical mesh material for several decades. This non-degradable synthetic polymer provides mechanical strength, a predictable host response, and its use has resulted in reduced recurrence rates for ventral hernia and pelvic organ prolapse. However, polypropylene and similar synthetic materials are associated with a chronic local tissue inflammatory response and dense fibrous tissue deposition. These outcomes have prompted variations in mesh design to minimize the surface area interface and increase integration with host tissue. In contrast, biologic scaffold materials composed of extracellular matrix (ECM) are rapidly degraded in-vivo and are associated with constructive tissue remodeling and minimal fibrosis. The objective of the present study was to assess the effects of an ECM hydrogel coating on the long-term host tissue response to polypropylene mesh in a rodent model of abdominal muscle injury. At 14 days post implantation, the ECM coated polypropylene mesh devices showed a decreased inflammatory response as characterized by the number and distribution of M1 macrophages (CD86+/CD68+) around mesh fibers when compared to the uncoated mesh devices. At 180 days the ECM coated polypropylene showed decreased density of collagen and amount of mature type I collagen deposited between mesh fibers when compared to the uncoated mesh devices. This study confirms and extends previous findings that an ECM coating mitigates the chronic inflammatory response and associated scar tissue deposition characteristic of polypropylene. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Mesh Location in Open Ventral Hernia Repair: A Systematic Review and Network Meta-analysis. (United States)

    Holihan, Julie L; Nguyen, Duyen H; Nguyen, Mylan T; Mo, Jiandi; Kao, Lillian S; Liang, Mike K


    There is no consensus on the ideal location for mesh placement in open ventral hernia repair (OVHR). We aim to identify the mesh location associated with the lowest rate of recurrence following OVHR using a systematic review and meta-analysis. A search was performed for studies comparing at least two of four locations for mesh placement during OVHR (onlay, inlay, sublay, and underlay). Outcomes assessed were hernia recurrence and surgical site infection (SSI). Pairwise meta-analysis was performed to compare all direct treatment of mesh locations. A multiple treatment meta-analysis was performed to compare all mesh locations in the Bayesian framework. Sensitivity analyses were planned for the following: studies with a low risk of bias, incisional hernias, by hernia size, and by mesh type (synthetic or biologic). Twenty-one studies were identified (n = 5,891). Sublay placement of mesh was associated with the lowest risk for recurrence [OR 0.218 (95% CI 0.06-0.47)] and was the best of the four treatment modalities assessed [Prob (best) = 94.2%]. Sublay was also associated with the lowest risk for SSI [OR 0.449 (95% CI 0.12-1.16)] and was the best of the 4 treatment modalities assessed [Prob (best) = 77.3%]. When only assessing studies at low risk of bias, of incisional hernias, and using synthetic mesh, the probability that sublay had the lowest rate of recurrence and SSI was high. Sublay mesh location has lower complication rates than other mesh locations. While additional randomized controlled trials are needed to validate these findings, this network meta-analysis suggests the probability of sublay being the best location for mesh placement is high.

  17. Mesh complications in female pelvic floor reconstructive surgery and their management: A systematic review

    Directory of Open Access Journals (Sweden)

    Hemendra N Shah


    Full Text Available We reviewed the incidence, predisposing factors, presentation and management of complications related to the use of synthetic mesh in the management of stress urinary incontinence and pelvic organ prolapse repair. Immediate complications, such as bleeding, hematoma, injury to adjacent organs during placement of mesh and complication of voiding dysfunction are not discussed in this review, since they are primarily related to technique. A PubMed search of related articles published in English was done from April 2008 to March 2011. Key words used were urinary incontinence, mesh, complications, midurethral sling, anterior prolapse, anterior vaginal repair, pelvic organ prolapse, transvaginal mesh, vault prolapse, midurethral slings, female stress urinary incontinence, mesh erosion, vaginal mesh complications, and posterior vaginal wall prolapse. Since there were very few articles dealing with the management of mesh-related complications in the period covered in the search we extended the search from January 2005 onwards. Articles were selected to fit the scope of the topic. In addition, landmark publications and Manufacturer and User Facility Device Experience (MAUDE data (FDA website were included on the present topic. A total of 170 articles were identified. The use of synthetic mesh in sub-urethral sling procedures is now considered the standard for the surgical management of stress urinary incontinence. Synthetic mesh is being increasingly used in the management of pelvic organ prolapse. While the incidence of extrusion and erosion with mid-urethral sling is low, the extrusion rate in prolapse repair is somewhat higher and the use in posterior compartment remains controversial. When used through the abdominal approach the extrusion and erosion rates are lower. The management of mesh complication is an individualized approach. The choice of the technique should be based on the type of mesh complication, location of the extrusion and/or erosion

  18. Prevention of Incisional Hernias with Biological Mesh: A Systematic Review of the Literature. (United States)

    Muysoms, Filip E; Jairam, An; López-Cano, Manuel; Śmietański, Maciej; Woeste, Guido; Kyle-Leinhase, Iris; Antoniou, Stavros A; Köckerling, Ferdinand


    Prophylactic mesh-augmented reinforcement during closure of abdominal wall incisions has been proposed in patients with increased risk for development of incisional hernias (IHs). As part of the BioMesh consensus project, a systematic literature review has been performed to detect those studies where MAR was performed with a non-permanent absorbable mesh (biological or biosynthetic). A computerized search was performed within 12 databases (Embase, Medline, Web-of-Science, Scopus, Cochrane, CINAHL, Pubmed publisher, Lilacs, Scielo, ScienceDirect, ProQuest, Google Scholar) with appropriate search terms. Qualitative evaluation was performed using the MINORS score for cohort studies and the Jadad score for randomized clinical trials (RCTs). For midline laparotomy incisions and stoma reversal wounds, two RCTs, two case-control studies, and two case series were identified. The studies were very heterogeneous in terms of mesh configuration (cross linked versus non-cross linked), mesh position (intraperitoneal versus retro-muscular versus onlay), surgical indication (gastric bypass versus aortic aneurysm), outcome results (effective versus non-effective). After qualitative assessment, we have to conclude that the level of evidence on the efficacy and safety of biological meshes for prevention of IHs is very low . No comparative studies were found comparing biological mesh with synthetic non-absorbable meshes for the prevention of IHs. There is no evidence supporting the use of non-permanent absorbable mesh (biological or biosynthetic) for prevention of IHs when closing a laparotomy in high-risk patients or in stoma reversal wounds. There is no evidence that a non-permanent absorbable mesh should be preferred to synthetic non-absorbable mesh, both in clean or clean-contaminated surgery.

  19. Prevention of Incisional Hernias with Biological MeshA Systematic Review of the Literature

    Directory of Open Access Journals (Sweden)



    Full Text Available Background: Prophylactic mesh augmented reinforcement during closure of abdominal wall incisions has been proposed in patients with increased risk for development of incisional hernias (IH. As part of the BioMesh consensus project, a systematic literature review has been performed to detect those studies where MAR was performed with a non-permanent absorbable mesh (biological or biosynthetic. Methods: A computerized search was performed within 12 databases (Embase, Medline, Web-of-Science, Scopus, Cochrane, CINAHL, Pubmed publisher, Lilacs, Scielo, ScienceDirect, ProQuest, Google scholar with appropriate search terms. Qualitative evaluation was performed using the MINORS score for cohort studies and the Jadad score for RCTs. Results: For midline laparotomy incisions and stoma reversal wounds, 2 RCTs, 2 case control studies and 2 case series were identified. The studies were very heterogeneous in terms of mesh configuration (cross linked versus non cross linked, mesh position (intraperitoneal versus retromuscular versus onlay, surgical indication (gastric bypass versus aortic aneurysm, outcome results (effective versus non effective. After qualitative assessment we have to conclude that the level of evidence on the efficacy and safety of biological meshes for prevention of incisional hernias is very low. No comparative studies were found comparing biological mesh with synthetic non-absorbable meshes for the prevention of incisional hernias. Conclusion: There is no evidence supporting the use of non-permanent absorbable mesh (biological or biosynthetic for prevention of incisional hernias when closing a laparotomy in high-risk patients or in stoma reversal wounds. There is no evidence that a non-permanent absorbable mesh should be preferred to synthetic non-absorbable mesh both in clean or clean-contaminated surgery.

  20. Effects of the polypropylene mesh implanted through inguinotomy in the spermatic funiculus, epididium and testis of dogs

    Directory of Open Access Journals (Sweden)

    Goldenberg Alberto


    Full Text Available PURPOSE: To investigate the effects of polypropylene mesh, implanted by inguinotomy, in the spermatic funiculus, epididium and testis of dogs. METHODS: Eighteen dogs were considered (12-23 Kg, separated in three groups. Group A (n=7: left side (with mesh versus right side (without mesh; Group B (n=7: left side (without mesh versus right side (with mesh and Group C (n=4: without any surgical manipulation (control group. After being observed for 60 days, the animals were subjected to bilateral removal of the spermatic funiculus, epididium and testis that were submitted to histological analysis. During the re-operation, a macroscopic evaluation was performed. RESULTS: On the mesh side, we noted 100% of mesh adherence to the posterior wall of the inguinal canal, as well as the adherence of the spermatic funiculus to the mesh. A congestion of the pampiniform plexus was noted in three animals. Chronic inflammation reaction and foreign body reaction in the spermatic funiculus was observed in 100% of the animals. On the side that did not carry a mesh, chronic inflammatory reaction was observed in 71% of the animals. All the animals presented chronic inflammatory reaction in the deferent duct in the mesh side and in eleven animals in the side without the mesh. These alterations were not found in Group C. There was a considerable statistical reduction in the average difference of the diameter of the lumen of the deferent duct in the mesh side. In the epididium and testis, macro and microscopic alterations were not significant, although one animal presented a marked reduction of spermatogenesis on the mesh side. CONCLUSION: The polypropylene mesh, when in contact with the spermatic funiculus of dogs, causes a more intense chronic inflammatory reaction and a significant reduction in the diameter of the lumen of the deferent duct.

  1. Comparative efficacy of Prolene and Prolene-Vicryl composite mesh for experimental ventral hernia repair in dogs. (United States)

    Anjum, H; Bokhari, S G; Khan, M A; Awais, M; Mughal, Z U; Shahzad, H K; Ijaz, F; Siddiqui, M I; Khan, I U; Chaudhry, A S; Akhtar, R; Aslam, S; Akbar, H; Asif, M; Maan, M K; Khan, M A; Noor, A; Khan, W A; Ullah, A; Hayat, M A


    In this study, efficacy of two hernia mesh implants viz. conventional Prolene and a novel Prolene-Vicryl composite mesh was assessed for experimental ventral hernia repair in dogs. Twelve healthy mongrel dogs were selected and randomly divided into three groups, A, Band C (n=4). In all groups, an experimental laparotomy was performed; thereafter, the posterior rectus sheath and peritoneum were sutured together, while, a 5 × 5 cm defect was created in the rectus muscle belly and anterior rectus sheath. For sublay hernioplasty, the hernia mesh (Prolene: group A; Prolene-Vicryl composite mesh: group B), was implanted over the posterior rectus sheath. In group C (control), mesh was not implanted; instead the laparotomy incision was closed after a herniorrhaphy. Post-operative pain, mesh shrinkage and adhesion formation were assessed as short term complications. Post-operatively, pain at surgical site was significantly less (P<0.001) in group B (composite mesh); mesh shrinkage was also significantly less in group B (21.42%, P<0.05) than in group A (Prolene mesh shrinkage: 58.18%). Group B (composite mesh) also depicted less than 25% adhesions (Mean ± SE: 0.75 ± 0.50 scores, P≤0.013) when assessed on the basis of a Quantitative Modified Diamond scale; a Qualitative Adhesion Tenacity scale also depicted either no adhesions (n=2), or, only flimsy adhesions (n=2) in group B (composite mesh), in contrast to group A (Prolene), which manifested greater adhesion formation and presence of dense adhesions requiring blunt dissection. Conclusively, the Prolene-Vicryl composite mesh proved superior to the Prolene mesh regarding lesser mesh contraction, fewer adhesions and no short-term follow-up complications.

  2. Multigrid for refined triangle meshes

    Energy Technology Data Exchange (ETDEWEB)

    Shapira, Yair


    A two-level preconditioning method for the solution of (locally) refined finite element schemes using triangle meshes is introduced. In the isotropic SPD case, it is shown that the condition number of the preconditioned stiffness matrix is bounded uniformly for all sufficiently regular triangulations. This is also verified numerically for an isotropic diffusion problem with highly discontinuous coefficients.

  3. On the Mesh Array for Matrix Multiplication


    Kak, Subhash


    This article presents new properties of the mesh array for matrix multiplication. In contrast to the standard array that requires 3n-2 steps to complete its computation, the mesh array requires only 2n-1 steps. Symmetries of the mesh array computed values are presented which enhance the efficiency of the array for specific applications. In multiplying symmetric matrices, the results are obtained in 3n/2+1 steps. The mesh array is examined for its application as a scrambling system.

  4. 6th International Meshing Roundtable '97

    Energy Technology Data Exchange (ETDEWEB)

    White, D.


    The goal of the 6th International Meshing Roundtable is to bring together researchers and developers from industry, academia, and government labs in a stimulating, open environment for the exchange of technical information related to the meshing process. In the pas~ the Roundtable has enjoyed significant participation born each of these groups from a wide variety of countries. The Roundtable will consist of technical presentations from contributed papers and abstracts, two invited speakers, and two invited panels of experts discussing topics related to the development and use of automatic mesh generation tools. In addition, this year we will feature a "Bring Your Best Mesh" competition and poster session to encourage discussion and participation from a wide variety of mesh generation tool users. The schedule and evening social events are designed to provide numerous opportunities for informal dialog. A proceedings will be published by Sandia National Laboratories and distributed at the Roundtable. In addition, papers of exceptionally high quaIity will be submitted to a special issue of the International Journal of Computational Geometry and Applications. Papers and one page abstracts were sought that present original results on the meshing process. Potential topics include but are got limited to: Unstructured triangular and tetrahedral mesh generation Unstructured quadrilateral and hexahedral mesh generation Automated blocking and structured mesh generation Mixed element meshing Surface mesh generation Geometry decomposition and clean-up techniques Geometry modification techniques related to meshing Adaptive mesh refinement and mesh quality control Mesh visualization Special purpose meshing algorithms for particular applications Theoretical or novel ideas with practical potential Technical presentations from industrial researchers.

  5. The mesh network protocol evaluation and development


    Pei, Ping; Petrenko, Y. N.


    In this paper, we introduce a Mesh network protocol evaluation and development. It has a special protocol. We could easily to understand that how different protocols are used in mesh network. In addition to our comprehension, Multi – hop routing protocol could provide robustness and load balancing to communication in wireless mesh networks.

  6. Mesh network achieve its fuction on Linux


    Pei, Ping; Petrenko, Y. N.


    In this paper, we introduce a Mesh network protocol evaluation and development. It has a special protocol. We could easily understand the Linux operation principles which are in use in mesh network. In addition to our comprehension, we describe the graph which shows package routing way. At last according to testing we prove that Mesh protocol AODV satisfy Linux platform performance requirements.

  7. User Manual for the PROTEUS Mesh Tools

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Micheal A. [Argonne National Lab. (ANL), Argonne, IL (United States); Shemon, Emily R [Argonne National Lab. (ANL), Argonne, IL (United States)


    PROTEUS is built around a finite element representation of the geometry for visualization. In addition, the PROTEUS-SN solver was built to solve the even-parity transport equation on a finite element mesh provided as input. Similarly, PROTEUS-MOC and PROTEUS-NEMO were built to apply the method of characteristics on unstructured finite element meshes. Given the complexity of real world problems, experience has shown that using commercial mesh generator to create rather simple input geometries is overly complex and slow. As a consequence, significant effort has been put into place to create multiple codes that help assist in the mesh generation and manipulation. There are three input means to create a mesh in PROTEUS: UFMESH, GRID, and NEMESH. At present, the UFMESH is a simple way to generate two-dimensional Cartesian and hexagonal fuel assembly geometries. The UFmesh input allows for simple assembly mesh generation while the GRID input allows the generation of Cartesian, hexagonal, and regular triangular structured grid geometry options. The NEMESH is a way for the user to create their own mesh or convert another mesh file format into a PROTEUS input format. Given that one has an input mesh format acceptable for PROTEUS, we have constructed several tools which allow further mesh and geometry construction (i.e. mesh extrusion and merging). This report describes the various mesh tools that are provided with the PROTEUS code giving both descriptions of the input and output. In many cases the examples are provided with a regression test of the mesh tools. The most important mesh tools for any user to consider using are the MT_MeshToMesh.x and the MT_RadialLattice.x codes. The former allows the conversion between most mesh types handled by PROTEUS while the second allows the merging of multiple (assembly) meshes into a radial structured grid. Note that the mesh generation process is recursive in nature and that each input specific for a given mesh tool (such as .axial

  8. Effects of Chitosan Coatings on Polypropylene Mesh for Implantation in a Rat Abdominal Wall Model (United States)

    Udpa, Natasha; Iyer, Shama R.; Rajoria, Rohit; Breyer, Kate E.; Valentine, Helen; Singh, Bhupinder; McDonough, Sean P.; Brown, Bryan N.; Bonassar, Lawrence J.


    Hernia repair and pelvic floor reconstruction are usually accompanied with the implantation of a surgical mesh, which frequently results in a foreign body response with associated complications. An ideal surgical mesh that allows force generation of muscle tissues without significant granulation tissue and/or fibrosis is of significant clinical interest. The objective of the present study was to evaluate the in vitro and in vivo responses of a chitosan coating on polypropylene mesh (Ch-PPM) in comparison with commercially available meshes. We found that application of a 0.5% (w/v) Ch-PPM elicited preferential attachment of myoblasts over fibroblast attachment in vitro. Therefore, we test the hypothesis that 0.5% Ch-PPM will encourage skeletal muscle tissue ingrowth and decrease fibrosis formation in vivo. We implanted 0.5% Ch-PPM, collagen-coated polypropylene mesh (Pelvitex™; C.R. Bard), and polypropylene (Avaulta Solo®; C.R. Bard) alone using a rat abdominal defect model. Force generation capacity and inflammatory response of each mesh were evaluated 2, 4, and 12 weeks postimplantation. We found that chitosan coating is associated with the restoration of functional skeletal muscle with histomorphologic characteristics that resemble native muscle and an early macrophage phenotypic response that has previously been shown to lead to more functional outcomes. PMID:23859182

  9. In vitro activation of human leukocytes in response to contact with synthetic hernia meshes. (United States)

    Bryan, N; Ahswin, H; Smart, N J; Bayon, Y; Hunt, J A


    Evaluation of an in vitro chemiluminescent screen to predict leukocyte ROS in response to surgical materials. 6 surgical meshes; manufacture and knitting variations of polypropylene (PP), polyester terephtalate (PET) and polyglycolic acid (PGA) trialled healthy human blood (n=5). Materials and blood were incubated with pholasin. Pholasin emits photons in the presence of reactive oxygen species; secreted by activated leukocytes. Multifilament-PGA mesh stimulated the greatest ROS response from blood derived human leukocytes. Multifilament-PET light weight and multifilament-PP meshes stimulated similar levels of ROS production which were greater than monofilament-PP light, monofilament-PP and monofilament-PET light meshes. Data demonstrated statistical variations in trans-donor response to the materials. An in vitro chemiluminescent assay can be used to assess leukocyte respiratory burst response to biomaterials. PGA mesh elicited the greatest ROS response. PP and PET monofilament meshes induce less ROS than multifilament equivalents. In vitro results correlate with previously published clinical responses to these materials. Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  10. Committee Opinion No. 694: Management of Mesh and Graft Complications in Gynecologic Surgery. (United States)


    This document focuses on the management of complications related to mesh used to correct stress urinary incontinence or pelvic organ prolapse. Persistent vaginal bleeding, vaginal discharge, or recurrent urinary tract infections after mesh placement should prompt an examination and possible further evaluation for exposure or erosion. A careful history and physical examination is essential in the diagnosis of mesh and graft complications. A clear understanding of the location and extent of mesh placement, as well as the patient's symptoms and therapy goals, are necessary to plan treatment approaches. It is important that a treating obstetrician-gynecologist or other gynecologic care provider who seeks to revise or remove implanted mesh be aware of the details of the index procedure. Diagnostic testing for a suspected mesh complication can include cystoscopy, proctoscopy, colonoscopy, or radiologic imaging. These tests should be pursued to answer specific questions related to management. Given the diverse nature of complications related to mesh-augmented pelvic floor surgery, there are no universal recommendations regarding minimum testing. Approaches to management of mesh-related complications in pelvic floor surgery include observation, physical therapy, medications, and surgery. Obstetrician-gynecologists should counsel women who are considering surgical revision or removal of mesh about the complex exchanges that can occur between positive and adverse pelvic floor functions across each additional procedure starting with the device implant. Detailed counseling regarding the risks and benefits of mesh revision or removal surgery is essential and can be conducted most thoroughly by a clinician who has experience performing these procedures. For women who are not symptomatic, there is no role for intervention.

  11. Committee Opinion No. 694 Summary: Management of Mesh and Graft Complications in Gynecologic Surgery. (United States)


    This document focuses on the management of complications related to mesh used to correct stress urinary incontinence or pelvic organ prolapse. Persistent vaginal bleeding, vaginal discharge, or recurrent urinary tract infections after mesh placement should prompt an examination and possible further evaluation for exposure or erosion. A careful history and physical examination is essential in the diagnosis of mesh and graft complications. A clear understanding of the location and extent of mesh placement, as well as the patient's symptoms and therapy goals, are necessary to plan treatment approaches. It is important that a treating obstetrician-gynecologist or other gynecologic care provider who seeks to revise or remove implanted mesh be aware of the details of the index procedure. Diagnostic testing for a suspected mesh complication can include cystoscopy, proctoscopy, colonoscopy, or radiologic imaging. These tests should be pursued to answer specific questions related to management. Given the diverse nature of complications related to mesh-augmented pelvic floor surgery, there are no universal recommendations regarding minimum testing. Approaches to management of mesh-related complications in pelvic floor surgery include observation, physical therapy, medications, and surgery. Obstetrician-gynecologists should counsel women who are considering surgical revision or removal of mesh about the complex exchanges that can occur between positive and adverse pelvic floor functions across each additional procedure starting with the device implant. Detailed counseling regarding the risks and benefits of mesh revision or removal surgery is essential and can be conducted most thoroughly by a clinician who has experience performing these procedures. For women who are not symptomatic, there is no role for intervention.

  12. 22nd International Meshing Roundtable

    CERN Document Server

    Staten, Matthew


    This volume contains the articles presented at the 22nd International Meshing Roundtable (IMR) organized, in part, by Sandia National Laboratories and was held on Oct 13-16, 2013 in Orlando, Florida, USA.  The first IMR was held in 1992, and the conference series has been held annually since.  Each year the IMR brings together researchers, developers, and application experts in a variety of disciplines, from all over the world, to present and discuss ideas on mesh generation and related topics.  The technical papers in this volume present theoretical and novel ideas and algorithms with practical potential, as well as technical applications in science and engineering, geometric modeling, computer graphics and visualization.

  13. 21st International Meshing Roundtable

    CERN Document Server

    Weill, Jean-Christophe


    This volume contains the articles presented at the 21st International Meshing Roundtable (IMR) organized, in part, by Sandia National Laboratories and was held on October 7–10, 2012 in San Jose, CA, USA. The first IMR was held in 1992, and the conference series has been held annually since. Each year the IMR brings together researchers, developers, and application experts in a variety of disciplines, from all over the world, to present and discuss ideas on mesh generation and related topics. The technical papers in this volume present theoretical and novel ideas and algorithms with practical potential, as well as technical applications in science and engineering, geometric modeling, computer graphics, and visualization.

  14. Voltammetry at micro-mesh electrodes

    Directory of Open Access Journals (Sweden)

    Wadhawan Jay D.


    Full Text Available The voltammetry at three micro-mesh electrodes is explored. It is found that at sufficiently short experimental durations, the micro-mesh working electrode first behaves as an ensemble of microband electrodes, then follows the behaviour anticipated for an array of diffusion-independent micro-ring electrodes of the same perimeter as individual grid-squares within the mesh. During prolonged electrolysis, the micro-mesh electrode follows that behaviour anticipated theoretically for a cubically-packed partially-blocked electrode. Application of the micro-mesh electrode for the electrochemical determination of carbon dioxide in DMSO electrolyte solutions is further illustrated.

  15. On the flexibility of Kokotsakis meshes


    Karpenkov, Oleg


    In this paper we study geometric, algebraic, and computational aspects of flexibility and infinitesimal flexibility of Kokotsakis meshes. A Kokotsakis mesh is a mesh that consists of a face in the middle and a certain band of faces attached to the middle face by its perimeter. In particular any 3x3-mesh made of quadrangles is a Kokotsakis mesh. We express the infinitesimal flexibility condition in terms of Ceva and Menelaus theorems. Further we study semi-algebraic properties of the set of fl...

  16. Adaptive Mesh Refinement in CTH

    International Nuclear Information System (INIS)

    Crawford, David


    This paper reports progress on implementing a new capability of adaptive mesh refinement into the Eulerian multimaterial shock- physics code CTH. The adaptivity is block-based with refinement and unrefinement occurring in an isotropic 2:1 manner. The code is designed to run on serial, multiprocessor and massive parallel platforms. An approximate factor of three in memory and performance improvements over comparable resolution non-adaptive calculations has-been demonstrated for a number of problems

  17. SHARP/PRONGHORN Interoperability: Mesh Generation

    Energy Technology Data Exchange (ETDEWEB)

    Avery Bingham; Javier Ortensi


    Progress toward collaboration between the SHARP and MOOSE computational frameworks has been demonstrated through sharing of mesh generation and ensuring mesh compatibility of both tools with MeshKit. MeshKit was used to build a three-dimensional, full-core very high temperature reactor (VHTR) reactor geometry with 120-degree symmetry, which was used to solve a neutron diffusion critical eigenvalue problem in PRONGHORN. PRONGHORN is an application of MOOSE that is capable of solving coupled neutron diffusion, heat conduction, and homogenized flow problems. The results were compared to a solution found on a 120-degree, reflected, three-dimensional VHTR mesh geometry generated by PRONGHORN. The ability to exchange compatible mesh geometries between the two codes is instrumental for future collaboration and interoperability. The results were found to be in good agreement between the two meshes, thus demonstrating the compatibility of the SHARP and MOOSE frameworks. This outcome makes future collaboration possible.

  18. Primary results of chest wall reconstruction with polydioxanone mesh on animals. (United States)

    Zheng, Ruan; Yong-Wu, Wang; Yong-Xing, Zhou; Shao-Hua, Wang


    With the development of surgical techniques and biomedical material, increasing synthetic materials are applied to the chest wall reconstruction, such as autologous rib, muscle flap, bovine pericardium and sheet metal. To detect the safety and efficiency of synthetic material Polydioxanone (PDO) in chest wall reconstruction. Healthy adult mongrel dogs operated with PDO, and then some clinical data were collected. Here we showed that PDO mesh could close down the function of chest wall defect, and PDO mesh could be degraded gradually and forms a fibrous layer with the surrounding tissues. Our data further demonstrated PDO mesh leads to slight lung adhesion with a small shrinkage. These findings thus provide the first evidence that the feasibility of PDO mesh in chest wall reconstruction in dogs.

  19. Case-matched series of a non-cross-linked biologic versus non-absorbable mesh in laparoscopic ventral rectopexy. (United States)

    Ogilvie, James W; Stevenson, Andrew R L; Powar, Michael


    Laparoscopic ventral mesh rectopexy (LVR) is an emerging technique for selected patients with rectal prolapse and obstructed defaecation syndrome. Data are insufficient to conclude which type of mesh affords the greatest benefit. Our aim was to compare the outcomes of LVR using a non-cross-linked biologic versus a permanent mesh. Twenty nine cases of LVR with permanent mesh were matched based on age and surgical indication with an equal number of patients using biologic mesh. Cases were retrospectively reviewed from a prospectively maintained database. Symptom resolution, patient satisfaction and recurrence of prolapse were measured among those who underwent LVR with either a biologic (Biodesign(®), Cook Medical) or polypropylene mesh. Age, American Society of Anesthesiologists (ASA) class, surgical indication and primary symptoms were not different between the two groups. After a median follow-up of 15.4 months, all patients reported being either completely or partially satisfied. Rates of complete or partial symptom resolution (p = 0.26) or satisfaction (p = 0.27) did not differ between groups. After LVR, similar rates of additional procedures were performed in the biologic (21 %) and the permanent (28 %) mesh group. Among patients with full-thickness prolapse (n = 33), there were five cases (15 %) of recurrence, one in the biologic group and four in the permanent mesh group (p = 0.37). There were no mesh-related complications in either group. LVR using a non-cross-linked biologic mesh appears to have comparable rates of symptom improvement and patient satisfaction in the short term. Longer follow-up will be required to determine if prolapse recurrence depends on mesh type.

  20. [Polypropylene mesh for testicular prothesis implantation: A report of 57 cases]. (United States)

    An, Jie; Liu, Ye; Zhang, Zong-min; Yu, Chun-xiao; Xia, Yong-qiang; Wang, Peng-fei


    To search for an optimum method for testicular prothesis implantation in the treatment of testis loss. We retrospectively analyzed the surgical methods and outcomes of 53 cases of terminal prostate cancer and 4 cases of unilateral testicular torsion treated by implantation of testicular prothesis with the polypropylene mesh. The 57 male patients all received testicular prothesis with the polypropylene mesh. All the patients were satisfied with the appearance and size of the scrotum after surgery. No scrotal hematoma, prosthesis infection, or autoimmune disease occurred postoperatively. Testis loss is not a rare condition clinically, for the treatment of which surgical implantation of testicular prothesis with the polypropylene mesh can achieve both a fine tissue compatibility and a desirable scrotal appearance.

  1. Cesarean section after abdominal mesh repair for pregnancy-related desmoid tumor: a case report

    Directory of Open Access Journals (Sweden)

    Ooi S


    Full Text Available Sara Ooi, Harry Ngo Obstetrics and Gynaecology Department, Liverpool Hospital, Liverpool, NSW, Australia Abstract: We report the case of a 32-year-old gravida 2 para 1 woman with a background of partially resected desmoid tumor (DT arising from the previous cesarean section (CS scar. This case details the management of her DT by surgical resection and mesh repair and second pregnancy following this. Pregnancy-related DTs are a relatively rare entity, and there is a paucity of literature regarding their management during pregnancy. There are only five reported cases of DTs arising from CS scars. To our knowledge, this is the only report to illustrate that subsequent CS is possible after desmoid resection and abdominal mesh repair. It provides evidence that CS can be safely accomplished following abdominal wall reconstructions and further arguments against elective lower segment CS. Keywords: abdominal wall, cesarean section, complications, desmoid tumor, surgical mesh

  2. Synthetic Versus Biological Mesh-Related Erosion After Laparoscopic Ventral Mesh Rectopexy: A Systematic Review. (United States)

    Balla, Andrea; Quaresima, Silvia; Smolarek, Sebastian; Shalaby, Mostafa; Missori, Giulia; Sileri, Pierpaolo


    This review reports the incidence of mesh-related erosion after ventral mesh rectopexy to determine whether any difference exists in the erosion rate between synthetic and biological mesh. A systematic search of the MEDLINE and the Ovid databases was conducted to identify suitable articles published between 2004 and 2015. The search strategy capture terms were laparoscopic ventral mesh rectopexy, laparoscopic anterior rectopexy, robotic ventral rectopexy, and robotic anterior rectopexy. Eight studies (3,956 patients) were included in this review. Of those patients, 3,517 patients underwent laparoscopic ventral rectopexy (LVR) using synthetic mesh and 439 using biological mesh. Sixty-six erosions were observed with synthetic mesh (26 rectal, 32 vaginal, 8 recto-vaginal fistulae) and one (perineal erosion) with biological mesh. The synthetic and the biological mesh-related erosion rates were 1.87% and 0.22%, respectively. The time between rectopexy and diagnosis of mesh erosion ranged from 1.7 to 124 months. No mesh-related mortalities were reported. The incidence of mesh-related erosion after LVR is low and is more common after the placement of synthetic mesh. The use of biological mesh for LVR seems to be a safer option; however, large, multicenter, randomized, control trials with long follow-ups are required if a definitive answer is to be obtained.

  3. Abdominal closure reinforcement by using polypropylene mesh functionalized with poly-epsilon-caprolactone nanofibers and growth factors for prevention of incisional hernia formation

    Czech Academy of Sciences Publication Activity Database

    Plencner, M.; East, B.; Tonar, Z.; Otáhal, M.; Prosecká, E.; Rampichová, M.; Krejčí, T.; Litvinec, Andrej; Buzgo, M.; Míčková, A.; Nečas, A.; Hoch, J.; Amler, E.


    Roč. 9, č. 2014 (2014), s. 3263-3227 E-ISSN 1178-2013 Institutional support: RVO:67985823 Keywords : nanofibers * growth factors * surgical mesh Subject RIV: FP - Other Medical Disciplines Impact factor: 4.383, year: 2014

  4. Assessment of pain and quality of life in Lichtenstein hernia repair using a new monofilament PTFE mesh: comparison of suture vs. fibrin sealant mesh fixation

    Directory of Open Access Journals (Sweden)

    René H Fortelny


    Full Text Available Background: Inguinal hernia repair is one of the most common operations in general surgery. The Lichtenstein tension-free operation has become the gold standard in open inguinal hernia repair. Despite the low recurrence rates, pain and discomfort remain a problem for a large number of patients. The aim of this study was to compare suture fixation vs. fibrin sealing by using a new monofilament PTFE mesh, i.e. the Infinit® mesh by W. L. Gore & Associates. Methods: This study was designed as a controlled prospective single-centre two cohort study. A total of 38 patients were enrolled and operated in Lichtenstein technique either standard suture mesh fixation or fibrin sealant mesh fixation were used as described in the TIMELI trial. Primary outcome parameters were postoperative complications with the new mesh (i.e. seroma, infection, pain and quality of life evaluated by the VAS and the SF-36 questionnaire. Secondary outcome was recurrence assessed by ultrasound and physical examination. Follow-up time was 1 year.Results: Significantly less postoperative pain was reported in the fibrin sealant group compared to the suture group at 6 weeks (P=0.035, 6 months (P=0.023 and 1 year (P=0.011 postoperatively. Additionally trends towards a higher postoperative quality of life, a faster surgical procedure and a shorter hospital stay were seen in the fibrin sealant group.Conclusion: Fibrin sealant mesh fixation in Lichtenstein hernioplasty effectively reduces acute and chronic postoperative pain. Monofilament, macro-porous, knitted PTFE meshes seem to be a practicable alternative to commonly used polypropylene meshes in open inguinal hernia repair.

  5. Laparoscopic appendicectomy for suspected mesh-induced appendicitis after laparoscopic transabdominal preperitoneal polypropylene mesh inguinal herniorraphy

    Directory of Open Access Journals (Sweden)

    Jennings Jason


    Full Text Available Laparoscopic inguinal herniorraphy via a transabdominal preperitoneal (TAPP approach using Polypropylene Mesh (Mesh and staples is an accepted technique. Mesh induces a localised inflammatory response that may extend to, and involve, adjacent abdominal and pelvic viscera such as the appendix. We present an interesting case of suspected Mesh-induced appendicitis treated successfully with laparoscopic appendicectomy, without Mesh removal, in an elderly gentleman who presented with symptoms and signs of acute appendicitis 18 months after laparoscopic inguinal hernia repair. Possible mechanisms for Mesh-induced appendicitis are briefly discussed.

  6. Bluetooth Low Energy Mesh Networks: A Survey. (United States)

    Darroudi, Seyed Mahdi; Gomez, Carles


    Bluetooth Low Energy (BLE) has gained significant momentum. However, the original design of BLE focused on star topology networking, which limits network coverage range and precludes end-to-end path diversity. In contrast, other competing technologies overcome such constraints by supporting the mesh network topology. For these reasons, academia, industry, and standards development organizations have been designing solutions to enable BLE mesh networks. Nevertheless, the literature lacks a consolidated view on this emerging area. This paper comprehensively surveys state of the art BLE mesh networking. We first provide a taxonomy of BLE mesh network solutions. We then review the solutions, describing the variety of approaches that leverage existing BLE functionality to enable BLE mesh networks. We identify crucial aspects of BLE mesh network solutions and discuss their advantages and drawbacks. Finally, we highlight currently open issues.

  7. Sierra toolkit computational mesh conceptual model

    International Nuclear Information System (INIS)

    Baur, David G.; Edwards, Harold Carter; Cochran, William K.; Williams, Alan B.; Sjaardema, Gregory D.


    The Sierra Toolkit computational mesh is a software library intended to support massively parallel multi-physics computations on dynamically changing unstructured meshes. This domain of intended use is inherently complex due to distributed memory parallelism, parallel scalability, heterogeneity of physics, heterogeneous discretization of an unstructured mesh, and runtime adaptation of the mesh. Management of this inherent complexity begins with a conceptual analysis and modeling of this domain of intended use; i.e., development of a domain model. The Sierra Toolkit computational mesh software library is designed and implemented based upon this domain model. Software developers using, maintaining, or extending the Sierra Toolkit computational mesh library must be familiar with the concepts/domain model presented in this report.

  8. [Using polypropylene mesh in surgery for stress urinary incontinence]. (United States)

    Murguía-Flores, Erick Arturo; Quintero-Granados, Fernando; Torres-Gómez, Luis Guillermo; Chávez-Navarro, Mariela Mariela; Vázquez-Gómez, Martha Berenice; Rodríguez-Rodríguez, Elizabeth


    Stress urinary incontinence (SUI) is defined as the involuntary leakage of urine while making an effort, such as coughing, sneezing or during activity. Since SUI generates high costs and affects the quality of life, it is important to make a proper diagnosis and, consequently, manage SUI efficiently. The objective was to know whether it is appropriate to use polypropylene mesh for SUI. A historical cohort was conducted by reviewing records of patients with SUI treated with polypropylene mesh during 2013 with a follow-up of 12 months. Urinary continence was achieved in 98% of patients at one year. The complication rate was 2%. Only 12% of patients had normal weight. The most commonly used surgery was the placement of tension-free transobturator tape. The healing average reported worldwide is 90%, while the average for complications is 10%. In this study we achieved similar results. Using polypropylene mesh for surgical correction of SUI is a safe and effective alternative; however, studies with larger populations and more extensive monitoring to clarify this situation are required.

  9. Floating shock fitting via Lagrangian adaptive meshes (United States)

    Vanrosendale, John


    In recent work we have formulated a new approach to compressible flow simulation, combining the advantages of shock-fitting and shock-capturing. Using a cell-centered on Roe scheme discretization on unstructured meshes, we warp the mesh while marching to steady state, so that mesh edges align with shocks and other discontinuities. This new algorithm, the Shock-fitting Lagrangian Adaptive Method (SLAM), is, in effect, a reliable shock-capturing algorithm which yields shock-fitted accuracy at convergence.

  10. Unstructured Polyhedral Mesh Thermal Radiation Diffusion

    International Nuclear Information System (INIS)

    Palmer, T.S.; Zika, M.R.; Madsen, N.K.


    Unstructured mesh particle transport and diffusion methods are gaining wider acceptance as mesh generation, scientific visualization and linear solvers improve. This paper describes an algorithm that is currently being used in the KULL code at Lawrence Livermore National Laboratory to solve the radiative transfer equations. The algorithm employs a point-centered diffusion discretization on arbitrary polyhedral meshes in 3D. We present the results of a few test problems to illustrate the capabilities of the radiation diffusion module

  11. Unstructured mesh adaptivity for urban flooding modelling (United States)

    Hu, R.; Fang, F.; Salinas, P.; Pain, C. C.


    Over the past few decades, urban floods have been gaining more attention due to their increase in frequency. To provide reliable flooding predictions in urban areas, various numerical models have been developed to perform high-resolution flood simulations. However, the use of high-resolution meshes across the whole computational domain causes a high computational burden. In this paper, a 2D control-volume and finite-element flood model using adaptive unstructured mesh technology has been developed. This adaptive unstructured mesh technique enables meshes to be adapted optimally in time and space in response to the evolving flow features, thus providing sufficient mesh resolution where and when it is required. It has the advantage of capturing the details of local flows and wetting and drying front while reducing the computational cost. Complex topographic features are represented accurately during the flooding process. For example, the high-resolution meshes around the buildings and steep regions are placed when the flooding water reaches these regions. In this work a flooding event that happened in 2002 in Glasgow, Scotland, United Kingdom has been simulated to demonstrate the capability of the adaptive unstructured mesh flooding model. The simulations have been performed using both fixed and adaptive unstructured meshes, and then results have been compared with those published 2D and 3D results. The presented method shows that the 2D adaptive mesh model provides accurate results while having a low computational cost.

  12. Meshes optimized for discrete exterior calculus (DEC).

    Energy Technology Data Exchange (ETDEWEB)

    Mousley, Sarah C. [Univ. of Illinois, Urbana-Champaign, IL (United States); Deakin, Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Knupp, Patrick [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mitchell, Scott A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    We study the optimization of an energy function used by the meshing community to measure and improve mesh quality. This energy is non-traditional because it is dependent on both the primal triangulation and its dual Voronoi (power) diagram. The energy is a measure of the mesh's quality for usage in Discrete Exterior Calculus (DEC), a method for numerically solving PDEs. In DEC, the PDE domain is triangulated and this mesh is used to obtain discrete approximations of the continuous operators in the PDE. The energy of a mesh gives an upper bound on the error of the discrete diagonal approximation of the Hodge star operator. In practice, one begins with an initial mesh and then makes adjustments to produce a mesh of lower energy. However, we have discovered several shortcomings in directly optimizing this energy, e.g. its non-convexity, and we show that the search for an optimized mesh may lead to mesh inversion (malformed triangles). We propose a new energy function to address some of these issues.

  13. Parallel adaptive simulations on unstructured meshes

    International Nuclear Information System (INIS)

    Shephard, M S; Jansen, K E; Sahni, O; Diachin, L A


    This paper discusses methods being developed by the ITAPS center to support the execution of parallel adaptive simulations on unstructured meshes. The paper first outlines the ITAPS approach to the development of interoperable mesh, geometry and field services to support the needs of SciDAC application in these areas. The paper then demonstrates the ability of unstructured adaptive meshing methods built on such interoperable services to effectively solve important physics problems. Attention is then focused on ITAPs' developing ability to solve adaptive unstructured mesh problems on massively parallel computers

  14. Use of polypropylene mesh in hernioplasty by Lichtenstein's technique

    International Nuclear Information System (INIS)

    Montejo Sainz, Jesus Enrique; Pisonero Socias, Juan Jose


    INTRODUCTION. The aim of present study was to assess the benefit using the prosthesis (polypropylene mesh) in the hernioplasty using the Lichtenstein's technique in the 'Joaquin Albarran' Clinical Surgical Hospital. METHODS. A prospective study (with an interval of 14 months) was conducted in 140 surgical interventions carried out using the Lichtenstein's technique in patients presenting with inguinal hernia. One hundred and ten patients were excluded due to interventions were of ambulatory method. The following data were studied: type of hernia found in the physical examination, age, sex, and race, type of job, intervention's date, and technique used as well as the complications during the immediate postoperative time. Also, the hernia's relapse after operation, surgical complications and tolerance to polypropylene mesh were taking into account. RESULTS. There was predominance of male sex confirming a direct influence among types of jobs requiring a strong physical effort and the appearance of inguinal hernias (63,3 %). There were only three complications: a hematoma and two seromas. There were not relapses and any case of infection, both local and systemic. The use of prophylactic antibiotics showed an appropriate cost-benefit relationship. CONCLUSIONS. The old age, the male sex and a sustained physical effort have a directly proportional relation to appearance of inguinal hernias. The feasibility of Lichtenstein's hernioplasty, the null incidence of hernia relapses and no appearance of complications including the rejection to prosthetic material, favoured the use of polypropylene in this plasty. Authors recommended the use of perioperative prophylactic antibiotic therapy to avoid wound's infection and thus to secure the result of surgical intervention and its durability. (author)

  15. Significant improvement of biocompatibility of polypropylene mesh for incisional hernia repair by using poly-ε-caprolactone nanofibers functionalized with thrombocyte-rich solution. (United States)

    Plencner, Martin; Prosecká, Eva; Rampichová, Michala; East, Barbora; Buzgo, Matej; Vysloužilová, Lucie; Hoch, Jiří; Amler, Evžen


    Incisional hernia is the most common postoperative complication, affecting up to 20% of patients after abdominal surgery. Insertion of a synthetic surgical mesh has become the standard of care in ventral hernia repair. However, the implementation of a mesh does not reduce the risk of recurrence and the onset of hernia recurrence is only delayed by 2-3 years. Nowadays, more than 100 surgical meshes are available on the market, with polypropylene the most widely used for ventral hernia repair. Nonetheless, the ideal mesh does not exist yet; it still needs to be developed. Polycaprolactone nanofibers appear to be a suitable material for different kinds of cells, including fibroblasts, chondrocytes, and mesenchymal stem cells. The aim of the study reported here was to develop a functionalized scaffold for ventral hernia regeneration. We prepared a novel composite scaffold based on a polypropylene surgical mesh functionalized with poly-ε-caprolactone (PCL) nanofibers and adhered thrombocytes as a natural source of growth factors. In extensive in vitro tests, we proved the biocompatibility of PCL nanofibers with adhered thrombocytes deposited on a polypropylene mesh. Compared with polypropylene mesh alone, this composite scaffold provided better adhesion, growth, metabolic activity, proliferation, and viability of mouse fibroblasts in all tests and was even better than a polypropylene mesh functionalized with PCL nanofibers. The gradual release of growth factors from biocompatible nanofiber-modified scaffolds seems to be a promising approach in tissue engineering and regenerative medicine.

  16. Biologic mesh versus synthetic mesh in open inguinal hernia repair: system review and meta-analysis. (United States)

    Fang, Zhixue; Ren, Feng; Zhou, Jianping; Tian, Jiao


    Biologic meshes are mostly used for abdominal wall reinforcement in infected fields, but no consensus has been reached on its use for inguinal hernia repairing. The purpose of this study was to compare biologic mesh with synthetic mesh in open inguinal herniorrhaphy. A systematic literature review and meta-analysis was undertaken to identify studies comparing the outcomes of biologic mesh and synthetic mesh in open inguinal hernia repair. Published studies were identified by the databases PubMed, EMBASE and the Cochrane Library. A total of 382 patients in five randomized controlled trials were reviewed (179 patients in biologic mesh group; 203 patients in synthetic mesh group). The two groups did not significantly differ in chronic groin pain (P = 0.06) or recurrence (P = 0.38). The incidence of seroma trended higher in biologic mesh group (P = 0.03). Operating time was significantly longer with biologic mesh (P = 0.03). There was no significant difference in hematomas (P = 0.23) between the two groups. From the data of this study, biologic mesh had no superiority to synthetic mesh in open inguinal hernia repair with similar recurrence rates and incidence of chronic groin pain, but higher rate of seroma and longer operating time. However, this mesh still needs to be assessed in a large, multicentre, well-designed randomized controlled trial. © 2015 Royal Australasian College of Surgeons.

  17. Tensile Behaviour of Welded Wire Mesh and Hexagonal Metal Mesh for Ferrocement Application (United States)

    Tanawade, A. G.; Modhera, C. D.


    Tension tests were conducted on welded mesh and hexagonal Metal mesh. Welded Mesh is available in the market in different sizes. The two types are analysed viz. Ø 2.3 mm and Ø 2.7 mm welded mesh, having opening size 31.75 mm × 31.75 mm and 25.4 mm × 25.4 mm respectively. Tensile strength test was performed on samples of welded mesh in three different orientations namely 0°, 30° and 45° degrees with the loading axis and hexagonal Metal mesh of Ø 0.7 mm, having opening 19.05 × 19.05 mm. Experimental tests were conducted on samples of these meshes. The objective of this study was to investigate the behaviour of the welded mesh and hexagonal Metal mesh. The result shows that the tension load carrying capacity of welded mesh of Ø 2.7 mm of 0° orientation is good as compared to Ø2.3 mm mesh and ductility of hexagonal Metal mesh is good in behaviour.

  18. Unstructured mesh based elastic wave modelling on GPU: a double-mesh grid method (United States)

    Yang, Kai; Zhang, Jianfeng; Gao, Hongwei


    We present an unstructured mesh based numerical technique for modelling elastic wave propagation in heterogeneous media with complex geometrical settings. The scheme is developed by adapting the so-called grid method with a double-mesh implementation. The double-mesh is generated by subdividing each triangular grid of the first-level mesh into a group of congruent smaller grids with equally dividing each edge of the triangle. The resulting double-mesh grid method incorporates the advantages of structured- and unstructured-mesh schemes. The irregular, unstructured first-level mesh, which is generated by centroidal Voronoi tessellation based on Delaunay triangulation with a velocity-dependent density function, can accurately describe the surface topography and interfaces, and the size of the grid cells can vary according to local velocities. Congruent smaller grids within each grid cell of the first-level mesh greatly reduce the memory requirement of geometrical coefficients compared to a whole irregular, unstructured mesh. Applying the double-mesh approach can also alleviate the discontinuity of memory accessing mainly caused by adoption of fully unstructured mesh. As a result, the GPU implementation of the proposed scheme can obtain a high speedup rate. Numerical examples demonstrate the good behaviour of the double-mesh elastic grid method.


    Directory of Open Access Journals (Sweden)



    Full Text Available INTRODUCTION Prospective study on Darning and Lichtenstein Mesh Hernioplasty in Inguinal Hernia Repair is a study of 61 cases of inguinal hernias which were treated by either open Inguinal hernia mesh repair (Lichtenstein or darning repair. The study was conducted with an objective to compare the effectiveness of these procedures and complications if any. 61 cases of inguinal hernia admitted in Yenepoya Medical College Hospital, Mangalore were selected on the basis of the non-probability (prospective sampling method. All patients with uncomplicated direct and indirect hernias treated by darning or mesh repair were included. After preoperative preparation they were randomly chosen for darning or mesh repair. The age/sex incidence, mode of presentation, precipitating factors, surgical treatment and postoperative complications were all evaluated and compared with standard published literature. The total number of postoperative complications was reported in 13.9% patients, complications was high after Mesh repair when compared to Darning. Seroma was the most common complication followed by funiculitis and wound infection. There was one recurrence each noted till date in the two groups under study. Darn repair is equally effective and much less costly treatment for inguinal hernia than mesh repair which had more risk of infection.

  20. Modifying hernia mesh design to improve device mechanical performance and promote tension-free repair. (United States)

    Ibrahim, Mohamed M; Poveromo, Luke P; Glisson, Richard R; Cornejo, Agustin; Farjat, Alfredo E; Gall, Ken; Levinson, Howard


    Approximately 348,000 ventral hernia repairs are performed annually in the United States and the incisional hernia recurrence rate is approximately 20% as a result of suture and mesh device failure. Device failure is related to changes at the suture/tissue interface that leads to acute or chronic suture pull-through and surgical failure. To better manage mechanical tension, we propose a modified mesh design with extensions and demonstrate its mechanical superiority. Comparative uniaxial static tensile testing was conducted on polypropylene suture and a modified mesh. Subsequently, a standard of care (SOC) mesh and modified mesh were evaluated using a tensometer in an acute hernia bench-top model. Modified mesh breaking strength, extension knot breaking strength, extension disruption, and extension anchoring were superior to suture (p design significantly improved device tension-free performance far beyond clinically relevant benchmarks (p design significantly improves device mechanical performance and enhances tension-free repair. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Polypropylene-based composite mesh versus standard polypropylene mesh in the reconstruction of complicated large abdominal wall hernias: a prospective randomized study. (United States)

    Kassem, M I; El-Haddad, H M


    To compare polypropylene mesh positioned onlay supported by omentum and/or peritoneum versus inlay implantation of polypropylene-based composite mesh in patients with complicated wide-defect ventral hernias. This was a prospective randomized study carried out on 60 patients presenting with complicated large ventral hernia in the period from January 2012 to January 2016 in the department of Gastrointestinal Surgery unit and Surgical Emergency of the Main Alexandria University Hospital, Egypt. Large hernia had an abdominal wall defect that could not be closed. Patients were divided into two groups of 30 patients according to the type of mesh used to deal with the large abdominal wall defect. The study included 38 women (63.3 %) and 22 men (37.7 %); their mean age was 46.5 years (range, 25-70). Complicated incisional hernia was the commonest presentation (56.7 %).The operative and mesh fixation times were longer in the polypropylene group. Seven wound infections and two recurrences were encountered in the propylene group. Mean follow-up was 28.7 months (2-48 months). Composite mesh provided, in one session, satisfactory results in patients with complicated large ventral hernia. The procedure is safe and effective in lowering operative time with a trend of low wound complication and recurrence rates.

  2. Adaptive mesh refinement in titanium

    Energy Technology Data Exchange (ETDEWEB)

    Colella, Phillip; Wen, Tong


    In this paper, we evaluate Titanium's usability as a high-level parallel programming language through a case study, where we implement a subset of Chombo's functionality in Titanium. Chombo is a software package applying the Adaptive Mesh Refinement methodology to numerical Partial Differential Equations at the production level. In Chombo, the library approach is used to parallel programming (C++ and Fortran, with MPI), whereas Titanium is a Java dialect designed for high-performance scientific computing. The performance of our implementation is studied and compared with that of Chombo in solving Poisson's equation based on two grid configurations from a real application. Also provided are the counts of lines of code from both sides.

  3. Converting skeletal structures to quad dominant meshes

    DEFF Research Database (Denmark)

    Bærentzen, Jakob Andreas; Misztal, Marek Krzysztof; Welnicka, Katarzyna


    We propose the Skeleton to Quad-dominant polygonal Mesh algorithm (SQM), which converts skeletal structures to meshes composed entirely of polar and annular regions. Both types of regions have a regular structure where all faces are quads except for a single ring of triangles at the center of eac...

  4. Parallel mesh management using interoperable tools.

    Energy Technology Data Exchange (ETDEWEB)

    Tautges, Timothy James (Argonne National Laboratory); Devine, Karen Dragon


    This presentation included a discussion of challenges arising in parallel mesh management, as well as demonstrated solutions. They also described the broad range of software for mesh management and modification developed by the Interoperable Technologies for Advanced Petascale Simulations (ITAPS) team, and highlighted applications successfully using the ITAPS tool suite.

  5. 7th International Meshing Roundtable '98

    Energy Technology Data Exchange (ETDEWEB)

    Eldred, T.J.


    The goal of the 7th International Meshing Roundtable is to bring together researchers and developers from industry, academia, and government labs in a stimulating, open environment for the exchange of technical information related to the meshing process. In the past, the Roundtable has enjoyed significant participation from each of these groups from a wide variety of countries.

  6. Laparoscopic Pelvic Floor Repair Using Polypropylene Mesh

    Directory of Open Access Journals (Sweden)

    Shih-Shien Weng


    Conclusion: Laparoscopic pelvic floor repair using a single piece of polypropylene mesh combined with uterosacral ligament suspension appears to be a feasible procedure for the treatment of advanced vaginal vault prolapse and enterocele. Fewer mesh erosions and postoperative pain syndromes were seen in patients who had no previous pelvic floor reconstructive surgery.

  7. Wrinkling prediction with adaptive mesh refinement

    NARCIS (Netherlands)

    Selman, A.; Meinders, Vincent T.; van den Boogaard, Antonius H.; Huetink, Han


    An adaptive mesh refinement procedure for wrinkling prediction analyses is presented. First the critical values are determined using Hutchinson’s bifurcation functional. A wrinkling risk factor is then defined and used to determined areas of potential wrinkling risk. Finally, a mesh refinement is

  8. A Comparative Study of Navigation Meshes

    NARCIS (Netherlands)

    van Toll, W.G.; Triesscheijn, Roy; Kallmann, Marcelo; Oliva, Ramon; Pelechano, Nuria; Pettré, Julien; Geraerts, R.J.


    A navigation mesh is a representation of a 2D or 3D virtual environment that enables path planning and crowd simulation for walking characters. Various state-of-the-art navigation meshes exist, but there is no standardized way of evaluating or comparing them. Each implementation is in a different

  9. Short-term outcomes of the transvaginal minimal mesh procedure for pelvic organ prolapse

    Directory of Open Access Journals (Sweden)

    Naoko Takazawa


    Full Text Available Purpose: This study aimed to evaluate the clinical outcomes and complications of transvaginal minimal mesh repair without using commercially available kits for treatment of pelvic organ prolapse (POP. Materials and Methods: This retrospective cohort study involved 91 women who underwent surgical management of POP with originally designed small mesh between July 2014 and August 2015. This mesh is 56% smaller than the mesh widely used in Japan, and it has only two arms delivered into each right and left sacrospinous ligament. The main study outcome was the anatomic cure rate defined as recurrence of POP quantification (POP-Q stage II or more. We also assessed changes in the overactive bladder symptom score (OABSS and prolapse quality of life questionnaire (P-QOL and evaluated adverse events. Finally, we compared patient backgrounds between the patients with and without recurrence. Results: Prolapse recurred in 10 of 91 patients (11.0%, and all patients with recurrence were diagnosed as POP-Q stage II. As adverse events, only mesh erosion occurred in two (2.2% and pelvic pain in one (1.1% of the 91 patients. The OABSS and P-QOL were significantly improved by the operation. When we compared patient backgrounds between the patients with and without recurrence, body mass index was the only factor influencing affecting recurrence. Conclusions: Transvaginal minimal mesh repair resulted in successful outcomes with low mesh-related complications and anatomic recurrence at one year. Furthermore, significant improvement in QOL was offered by this procedure. Our minimal mesh technique should be considered as one treatment option for the management of POP.

  10. Dynamic evaluation of pelvic floor reconstructive surgery using radiopaque meshes and three-dimensional helical CT

    Directory of Open Access Journals (Sweden)

    Paulo Palma


    Full Text Available PURPOSE: This prospective study was performed to achieve visualization of the reestablishment of anatomy after reconstructive surgery in the different pelvic compartments with non-absorbable radiopaque meshes, providing valuable anatomic information for surgeons implanting meshes. MATERIALS AND METHODS: A total of 30 female patients with stress urinary incontinence (SUI, anterior and posterior vaginal wall prolapse, or both underwent surgical repair using radiopaque meshes after written informed consent. Patients with SUI underwent five different surgeries. Patients with anterior vaginal prolapse underwent a procedure using a combined pre-pubic and transobturator mesh, and those with posterior vaginal prolapse underwent posterior slingplasty. Three-dimensional reconstruction using helical CT was performed four weeks postoperatively. RESULTS: In all cases, the mesh was clearly visualized. Transobturator slings were shown at the midurethra, and the anchoring tails perforated the obturator foramen at the safety region. Mini-slings were in the proper place, and computed angiography revealed that the anchoring system was away from the obturator vessels. In patients undergoing procedure for anterior vaginal prolapse, both pre-pubic armpit and obturator slings were clearly seen and the mesh was in the proper position, supporting the bladder base and occluding the distal part of the urogenital hiatus. Transcoccygeal sacropexy revealed indirectly a well-supported "neo rectovaginal fascia" and the anchoring tails at the level of ischial spines. CONCLUSION: Three-dimensional helical tomography images of the female pelvis using radiopaque meshes have a potential role in improving our understanding of pelvic floor reconstructive surgeries. These radiopaque meshes might be the basis of a new investigative methodology.

  11. A randomized controlled experimental study comparing chitosan coated polypropylene mesh and Proceed™ mesh for abdominal wall defect closure

    Directory of Open Access Journals (Sweden)

    S.T. Jayanth


    Conclusion: Chitosan coated polypropylene mesh was found to have similar efficacy to Proceed™ mesh. Chitosan coated polypropylene mesh, can act as an anti adhesive barrier when used in the repair of incisional hernias and abdominal wall defects.

  12. Boundary denoising for open surface meshes (United States)

    Lee, Wei Zhe; Lim, Wee Keong; Soo, Wooi King


    Recently, applications of open surfaces in 3D have emerged to be an interesting research topic due to the popularity of range cameras such as the Microsoft Kinect. However, surface meshes representing such open surfaces are often corrupted with noises especially at the boundary. Such deformity needs to be treated to facilitate further applications such as texture mapping and zippering of multiple open surface meshes. Conventional methods perform denoising by removing components with high frequencies, thus smoothing the boundaries. However, this may result in loss of information, as not all high frequency transitions at the boundaries correspond to noises. To overcome such shortcoming, we propose a combination of local information and geometric features to single out the noises or unusual vertices at the mesh boundaries. The local shape of the selected mesh boundaries regions, characterized by the mean curvature value, is compared with that of the neighbouring interior region. The neighbouring interior region is chosen such that it is the closest to the corresponding boundary region, while curvature evaluation is independent of the boundary. The smoothing processing is done via Laplacian smoothing with our modified weights to reduce boundary shrinkage. The evaluation of the algorithm is done by noisy meshes generated from controlled model clean meshes. The Hausdorff distance is used as the measurement between the meshes. We show that our method produces better results than conventional smoothing of the whole boundary loop.

  13. Fog water collection effectiveness: Mesh intercomparisons (United States)

    Fernandez, Daniel; Torregrosa, Alicia; Weiss-Penzias, Peter; Zhang, Bong June; Sorensen, Deckard; Cohen, Robert; McKinley, Gareth; Kleingartner, Justin; Oliphant, Andrew; Bowman, Matthew


    To explore fog water harvesting potential in California, we conducted long-term measurements involving three types of mesh using standard fog collectors (SFC). Volumetric fog water measurements from SFCs and wind data were collected and recorded in 15-minute intervals over three summertime fog seasons (2014–2016) at four California sites. SFCs were deployed with: standard 1.00 m2 double-layer 35% shade coefficient Raschel; stainless steel mesh coated with the MIT-14 hydrophobic formulation; and FogHa-Tin, a German manufactured, 3-dimensional spacer fabric deployed in two orientations. Analysis of 3419 volumetric samples from all sites showed strong relationships between mesh efficiency and wind speed. Raschel mesh collected 160% more fog water than FogHa-Tin at wind speeds less than 1 m s–1 and 45% less for wind speeds greater than 5 m s–1. MIT-14 coated stainless-steel mesh collected more fog water than Raschel mesh at all wind speeds. At low wind speeds of wind speeds of 4–5 m s–1, it collected 41% more. FogHa-Tin collected 5% more fog water when the warp of the weave was oriented vertically, per manufacturer specification, than when the warp of the weave was oriented horizontally. Time series measurements of three distinct mesh across similar wind regimes revealed inconsistent lags in fog water collection and inconsistent performance. Since such differences occurred under similar wind-speed regimes, we conclude that other factors play important roles in mesh performance, including in-situ fog event and aerosol dynamics that affect droplet-size spectra and droplet-to-mesh surface interactions.

  14. Mesh optimization for microbial fuel cell cathodes constructed around stainless steel mesh current collectors

    KAUST Repository

    Zhang, Fang


    Mesh current collectors made of stainless steel (SS) can be integrated into microbial fuel cell (MFC) cathodes constructed of a reactive carbon black and Pt catalyst mixture and a poly(dimethylsiloxane) (PDMS) diffusion layer. It is shown here that the mesh properties of these cathodes can significantly affect performance. Cathodes made from the coarsest mesh (30-mesh) achieved the highest maximum power of 1616 ± 25 mW m-2 (normalized to cathode projected surface area; 47.1 ± 0.7 W m-3 based on liquid volume), while the finest mesh (120-mesh) had the lowest power density (599 ± 57 mW m-2). Electrochemical impedance spectroscopy showed that charge transfer and diffusion resistances decreased with increasing mesh opening size. In MFC tests, the cathode performance was primarily limited by reaction kinetics, and not mass transfer. Oxygen permeability increased with mesh opening size, accounting for the decreased diffusion resistance. At higher current densities, diffusion became a limiting factor, especially for fine mesh with low oxygen transfer coefficients. These results demonstrate the critical nature of the mesh size used for constructing MFC cathodes. © 2010 Elsevier B.V. All rights reserved.

  15. Markov random fields on triangle meshes

    DEFF Research Database (Denmark)

    Andersen, Vedrana; Aanæs, Henrik; Bærentzen, Jakob Andreas


    In this paper we propose a novel anisotropic smoothing scheme based on Markov Random Fields (MRF). Our scheme is formulated as two coupled processes. A vertex process is used to smooth the mesh by displacing the vertices according to a MRF smoothness prior, while an independent edge process labels...... mesh edges according to a feature detecting prior. Since we should not smooth across a sharp feature, we use edge labels to control the vertex process. In a Bayesian framework, MRF priors are combined with the likelihood function related to the mesh formation method. The output of our algorithm...

  16. Engagement of Metal Debris into Gear Mesh (United States)

    handschuh, Robert F.; Krantz, Timothy L.


    A series of bench-top experiments was conducted to determine the effects of metallic debris being dragged through meshing gear teeth. A test rig that is typically used to conduct contact fatigue experiments was used for these tests. Several sizes of drill material, shim stock and pieces of gear teeth were introduced and then driven through the meshing region. The level of torque required to drive the "chip" through the gear mesh was measured. From the data gathered, chip size sufficient to jam the mechanism can be determined.

  17. Complications of Transvaginal Mesh for Pelvic Organ Prolapse and Stress Urinary Incontinence: Tips for Prevention, Recognition, and Management. (United States)

    MacDonald, Susan; Terlecki, Ryan; Costantini, Elisabetta; Badlani, Gopal


    Mesh-related complications following transvaginal management of pelvic organ prolapse (POP) and/or stress urinary incontinence (SUI) have received significant attention in the last decade. We sought to identify patient, product, and technical factors associated with an increased risk of complications after mesh-based transvaginal repair of anterior POP and SUI. In this review we clarify the different pattern of complications after POP and SUI repairs. Our aim is to provide a practical evidence-based guide for physicians to prevent and, if necessary, manage product-associated complications in a stepwise manner. We conducted a comprehensive PubMed search of all English-language articles published from 2010 to June 2016, using these search terms: mesh, pelvic organ prolapse, and stress urinary incontinence. Expert opinion is also provided. Mesh-related complications are much lower after repair of SUI compared with POP, despite its more frequent use. Vaginal exposure is the most common mesh-specific complication. Patients may present with vaginal discharge, dyspareunia, pain, recurrent urinary tract infection, and/or hematuria. Conversely, patients may be asymptomatic. Small asymptomatic mesh exposures (urinary tract must be fully excised. Following excision, pain may persist in up to 50% of patients. Vaginal extrusion, persistent pain, and urethral and/or bladder erosion are the three most common product-specific complications following mesh-based repair for SUI or POP. Conservative therapies may be attempted, but most patients ultimately require partial or complete mesh excision. We reviewed the recent literature on mesh-related complications after repair of pelvic organ prolapse (POP) and stress urinary incontinence (SUI). Vaginal exposure, persistent pain, and erosion into the urinary tract are the most common. These often require surgical management, best suited to a urologist with training and experience in this area. Evidence supports mesh use for correction of

  18. Surgical Audit

    African Journals Online (AJOL)


    Jan 6, 2010 ... A good way to describe the first surgical audits is that they were 'polite, restrained discussions'. This was the situation before the development of quality assurance in the business world. As this slowly infiltrated into the medical profession the discussions changed to more cri- teria based surgical audits.

  19. [Female genital prolapse surgery using ultra lightweight polypropylene mesh]. (United States)

    Filimonov, V B; Vasin, R V; Vasina, I V; Kaprin, A D; Kostin, A A


    To compare the results of female genital prolapse (FGP) surgery via vaginal access using lightweight and ultra-lightweight polypropylene mesh. From 2007 to 2011, 93 women aged from 46 to 71 years with II-IV stage FGP (POP-Q classification) were examined and underwent the vaginal extra-peritoneal colpopexy using polypropylene implants in the Department of Urology. Patients were divided into 2 groups. In patients of group 1 (n=50) the surgery was performed according to a newly developed technique using perforated ultra-lightweight (surface density 19 g/m2) domestically manufactured polypropylene implant. In group 2, a standard trocar set with light (surface density of 42.7 g/m2) foreign-made polypropylene implants was used. Long-term follow-up was from 1 to 5 years. General surgical complications (urinary bladder injury, blood loss over 300 ml, perineal and vaginal hematomas) were detected in 2 (4%) patients of group 1 and in 7 (16.3%) patients of group 2. The most common specific mesh-related complication was the vaginal wall erosion, which was observed in 4 (9.3%) patients of group 2 and in 1 (2%) patient of group 1. FGP recurrence was diagnosed in 5 (10%) patients of group 1 in the non-treated part and in 8 (18.6%) patients of group 2. Three patients (7%) in group 2 developed recurrent cystocele due to the shrinkage of the mesh implant which was not observed in group 1. At 12 month follow-up, the results of FGP surgical treatment were estimated as good (full functional recovery and no FGP recurrence) in 41 (82%) and 32 (74.4%) patients of groups 1 and 2, respectively. We have developed a method of vaginal extra-peritoneal colpopexy using a perforated ultra-lightweight polypropylene implant. This technique has resulted in the absence of recurrence in the treated part of FGP, and 4.1, 4.2 and 4.7 fold reductions in the incidence of general surgical complications, vaginal wall erosions and perineal and vaginal hematomas, respectively, compared with FGP patients

  20. LR: Compact connectivity representation for triangle meshes

    Energy Technology Data Exchange (ETDEWEB)

    Gurung, T; Luffel, M; Lindstrom, P; Rossignac, J


    We propose LR (Laced Ring) - a simple data structure for representing the connectivity of manifold triangle meshes. LR provides the option to store on average either 1.08 references per triangle or 26.2 bits per triangle. Its construction, from an input mesh that supports constant-time adjacency queries, has linear space and time complexity, and involves ordering most vertices along a nearly-Hamiltonian cycle. LR is best suited for applications that process meshes with fixed connectivity, as any changes to the connectivity require the data structure to be rebuilt. We provide an implementation of the set of standard random-access, constant-time operators for traversing a mesh, and show that LR often saves both space and traversal time over competing representations.

  1. Obtuse triangle suppression in anisotropic meshes

    KAUST Repository

    Sun, Feng


    Anisotropic triangle meshes are used for efficient approximation of surfaces and flow data in finite element analysis, and in these applications it is desirable to have as few obtuse triangles as possible to reduce the discretization error. We present a variational approach to suppressing obtuse triangles in anisotropic meshes. Specifically, we introduce a hexagonal Minkowski metric, which is sensitive to triangle orientation, to give a new formulation of the centroidal Voronoi tessellation (CVT) method. Furthermore, we prove several relevant properties of the CVT method with the newly introduced metric. Experiments show that our algorithm produces anisotropic meshes with much fewer obtuse triangles than using existing methods while maintaining mesh anisotropy. © 2011 Elsevier B.V. All rights reserved.

  2. Mesh Processing in Medical Image Analysis

    DEFF Research Database (Denmark)

    The following topics are dealt with: mesh processing; medical image analysis; interactive freeform modeling; statistical shape analysis; clinical CT images; statistical surface recovery; automated segmentation; cerebral aneurysms; and real-time particle-based representation....

  3. Shape space exploration of constrained meshes

    KAUST Repository

    Yang, Yongliang


    We present a general computational framework to locally characterize any shape space of meshes implicitly prescribed by a collection of non-linear constraints. We computationally access such manifolds, typically of high dimension and co-dimension, through first and second order approximants, namely tangent spaces and quadratically parameterized osculant surfaces. Exploration and navigation of desirable subspaces of the shape space with regard to application specific quality measures are enabled using approximants that are intrinsic to the underlying manifold and directly computable in the parameter space of the osculant surface. We demonstrate our framework on shape spaces of planar quad (PQ) meshes, where each mesh face is constrained to be (nearly) planar, and circular meshes, where each face has a circumcircle. We evaluate our framework for navigation and design exploration on a variety of inputs, while keeping context specific properties such as fairness, proximity to a reference surface, etc. © 2011 ACM.

  4. [Complications associated with the use of polypropylene mesh in women under colposacropexy]. (United States)

    Aguilera-Maldonado, Lizzete Verónica; Jiménez-Vieyra, Carlos Ramón; Solís-Moreno, Tania Kristal


    There have been numerous surgical procedures and modi fied in the hope of obtaining a lasting cure for pelvic organ prolapse These surgeries were performed using the traditionally native tissues of the patient. In an effort to reduce morbidity, improve surgical outcomes and reduce the complexity of these operations, we used a growing number of synthetic mesh repairs and biomaterials used tissue from cadaver or animal. To evaluate the frequency of complications associated with the use of polypropylene mesh in women undergoing colposacropexy. Retrospective, observational and descriptive study conducted at the Hospitalde Ginecología y Obstetricia 3 IMSS (Mexico) between 1 January 2006 and 15 February 2013. The main risk factors associated with pelvic organ prolapse were considered, comorbidity and complications directly linked to the procedure. With respect to the related complications colposacropexy procedure using polypropylene mesh were documented in 20 of 67 patients which corresponded to 30%. A number of complications have been associated with the use of meshes between these include: extrusion, erosion, pelvic pain, dyspareunia, bladder or bowel condition, but one aspect is poorly evaluated sexual dysfunction without to definitely plays an important role in the field bio-psychosocial.

  5. A Wrapping Method for Inserting Titanium Micro-Mesh Implants in the Reconstruction of Blowout Fractures

    Directory of Open Access Journals (Sweden)

    Tae Joon Choi


    Full Text Available Titanium micro-mesh implants are widely used in orbital wall reconstructions because they have several advantageous characteristics. However, the rough and irregular marginal spurs of the cut edges of the titanium mesh sheet impede the efficacious and minimally traumatic insertion of the implant, because these spurs may catch or hook the orbital soft tissue, skin, or conjunctiva during the insertion procedure. In order to prevent this problem, we developed an easy method of inserting a titanium micro-mesh, in which it is wrapped with the aseptic transparent plastic film that is used to pack surgical instruments or is attached to one side of the inner suture package. Fifty-four patients underwent orbital wall reconstruction using a transconjunctival or transcutaneous approach. The wrapped implant was easily inserted without catching or injuring the orbital soft tissue, skin, or conjunctiva. In most cases, the implant was inserted in one attempt. Postoperative computed tomographic scans showed excellent placement of the titanium micro-mesh and adequate anatomic reconstruction of the orbital walls. This wrapping insertion method may be useful for making the insertion of titanium micro-mesh implants in the reconstruction of orbital wall fractures easier and less traumatic.

  6. Polypropylene suture versus skin staples for securing mesh in lichtenstein inguinal hernioplasty. (United States)

    Khan, Awais Ali; Majeed, Shahid; Shahzadi, Maria; Hussain, Syed Mukarram; Ali, Mujahid Zulfiqar; Siddique, Khalid


    To compare polypropylene suture and skin staples for securing mesh in Lichtenstein inguinal hernioplasty in terms of mean operating time and postoperative pain. Randomized clinical trial. Surgical Ward, Combined Military Hospital, Kharian, from August 2011 to February 2012. All individuals fulfilling inclusion criteria underwent elective Lichtenstein inguinal hernioplasty as admitted patients, under spinal anaesthesia and with aseptic measures. In group 1, during the operation, mesh fixation was done with 2/0 polypropylene suture and skin was closed with subcuticular 2/0 polypropylene suture whereas in group 2, the anchorage of mesh was done with skin staples and skin was closed with staples from the same stapler. Mean operative time and postoperative pain, assessed on a visual analog score, were compared between the groups. The overall postoperative pain was lower (p = 0.026) when staples were used to anchor mesh. Moreover, operative time was also lower (37.42 ± 2.69 minutes) in staple group versus (42.44 ± 2.55 minutes in polypropylene group). Mean operating time and postoperative pain is less in securing mesh with skin staples as compared to polypropylene suture in Lichtenstein inguinal hernioplasty.

  7. Progressive compression of generic surface meshes


    Caillaud , Florian; Vidal , Vincent; Dupont , Florent; Lavoué , Guillaume


    International audience; This paper presents a progressive compression method for generic surface meshes (non-manifold and/or polygonal). Two major contributions are proposed : (1) generic edge collapse and vertex split operators allowing surface simplication and renement of a mesh, whatever its connectivity; (2) a distortion-aware collapse clustering strategy that adapts the decima-tion granularity in order to optimize the rate-distortion tradeoff.

  8. Towards Blockchain-enabled Wireless Mesh Networks


    Selimi, Mennan; Kabbinale, Aniruddh Rao; Ali, Anwaar; Navarro, Leandro; Sathiaseelan, Arjuna


    Recently, mesh networking and blockchain are two of the hottest technologies in the telecommunications industry. Combining both can reformulate internet access and make connecting to the Internet not only easy, but affordable too. Hyperledger Fabric (HLF) is a blockchain framework implementation and one of the Hyperledger projects hosted by The Linux Foundation. We evaluate HLF in a real production mesh network and in the laboratory, quantify its performance, bottlenecks and limitations of th...

  9. Quadrilateral/hexahedral finite element mesh coarsening (United States)

    Staten, Matthew L; Dewey, Mark W; Scott, Michael A; Benzley, Steven E


    A technique for coarsening a finite element mesh ("FEM") is described. This technique includes identifying a coarsening region within the FEM to be coarsened. Perimeter chords running along perimeter boundaries of the coarsening region are identified. The perimeter chords are redirected to create an adaptive chord separating the coarsening region from a remainder of the FEM. The adaptive chord runs through mesh elements residing along the perimeter boundaries of the coarsening region. The adaptive chord is then extracted to coarsen the FEM.

  10. Unstructured Mesh Movement and Viscous Mesh Generation for CFD-Based Design Optimization Project (United States)

    National Aeronautics and Space Administration — The innovations proposed are twofold: 1) a robust unstructured mesh movement method able to handle isotropic (Euler), anisotropic (viscous), mixed element (hybrid)...

  11. The finite element method in making up meshes in ANSYS Meshing for CFD models

    Directory of Open Access Journals (Sweden)

    Віктор Іванович Троханяк


    Full Text Available Method of finite elements (FEM is used in calculating tasks of hydrodynamics and heat transfer tasks. The essence of the method consists in the approximate solution of a variational task. To formulate this task a functional concept is used. The type of a functional is different for different tasks and is selected through a special choice. Currently FEM is widely used in calculating the strength and in solving tasks of heat transfer in solids. However, it can be applied in calculating the flow of liquids and gases. There are also methods that combine elements of the finite volumes and finite elements methods. The combination of these methods make it possible to use a wide range of computational meshes ( tetragonal meshes, pyramidal meshes, prismatic meshes, polyhedral meshes what is necessary for solving tasks with complex geometry. This approach is used by CFD packages Ansys CFX, Ansys Fluent, Star-CD, Star-CCM +, Comsol and others. The method and the analysis of 2D mesh were carried out, using a method of final elements in ANSYS Meshing for heat exchangers with an inline arrangement of tubes in banks and with their curvilinear arrangement in compact banks of tubes of a new design. Particular features were considered and the algorithm of making up a mesh was developed for tasks of hydraulic and gas dynamics and thermal mass transfer. The most optimum and qualitative meshes for CFD models were chosen

  12. Unstructured Mesh Movement and Viscous Mesh Generation for CFD-Based Design Optimization, Phase II (United States)

    National Aeronautics and Space Administration — The innovations proposed are twofold: 1) a robust unstructured mesh movement method able to handle isotropic (Euler), anisotropic (viscous), mixed element (hybrid)...

  13. Immediate titanium mesh cranioplasty for treatment of post-craniotomy infections (United States)

    Wind, Joshua J.; Ohaegbulam, Chima; Iwamoto, Fabio M.; Black, Peter McL.; Park, John K.


    OBJECTIVE Post craniotomy infections have generally been treated by debridement of infected tissues, disposal of the bone flap, and delayed cranioplasty several months later to repair the resulting skull defect. Debridement followed by retention of the bone flap has also been advocated. Here we propose an alternative operative strategy for the treatment of post craniotomy infections. METHODS Two patients presenting with clinical and radiographic signs and symptoms of post craniotomy infections were treated by debridement, bone flap disposal, and immediate titanium mesh cranioplasty. The patients were subsequently administered antibiotics and their clinical courses were followed. RESULTS The patients treated in this fashion did not have recurrence of their infections during three-year follow-up periods. CONCLUSIONS Surgical debridement, bone flap disposal and immediate titanium mesh cranioplasty may be a suitable option for the treatment of post craniotomy infections. This treatment strategy facilitates the eradication of infectious sources and obviates the risks and costs associated with a second surgical procedure. PMID:22120410

  14. Automatic Scheme Selection for Toolkit Hex Meshing

    Energy Technology Data Exchange (ETDEWEB)



    Current hexahedral mesh generation techniques rely on a set of meshing tools, which when combined with geometry decomposition leads to an adequate mesh generation process. Of these tools, sweeping tends to be the workhorse algorithm, accounting for at least 50% of most meshing applications. Constraints which must be met for a volume to be sweepable are derived, and it is proven that these constraints are necessary but not sufficient conditions for sweepability. This paper also describes a new algorithm for detecting extruded or sweepable geometries. This algorithm, based on these constraints, uses topological and local geometric information, and is more robust than feature recognition-based algorithms. A method for computing sweep dependencies in volume assemblies is also given. The auto sweep detect and sweep grouping algorithms have been used to reduce interactive user time required to generate all-hexahedral meshes by filtering out non-sweepable volumes needing further decomposition and by allowing concurrent meshing of independent sweep groups. Parts of the auto sweep detect algorithm have also been used to identify independent sweep paths, for use in volume-based interval assignment.

  15. How to model wireless mesh networks topology

    International Nuclear Information System (INIS)

    Sanni, M L; Hashim, A A; Anwar, F; Ali, S; Ahmed, G S M


    The specification of network connectivity model or topology is the beginning of design and analysis in Computer Network researches. Wireless Mesh Networks is an autonomic network that is dynamically self-organised, self-configured while the mesh nodes establish automatic connectivity with the adjacent nodes in the relay network of wireless backbone routers. Researches in Wireless Mesh Networks range from node deployment to internetworking issues with sensor, Internet and cellular networks. These researches require modelling of relationships and interactions among nodes including technical characteristics of the links while satisfying the architectural requirements of the physical network. However, the existing topology generators model geographic topologies which constitute different architectures, thus may not be suitable in Wireless Mesh Networks scenarios. The existing methods of topology generation are explored, analysed and parameters for their characterisation are identified. Furthermore, an algorithm for the design of Wireless Mesh Networks topology based on square grid model is proposed in this paper. The performance of the topology generated is also evaluated. This research is particularly important in the generation of a close-to-real topology for ensuring relevance of design to the intended network and validity of results obtained in Wireless Mesh Networks researches

  16. Stapled Mesh Reinforcement Technique (SMART) to Prevent Parastomal Hernias: Our Initial Experience and Review of the Literature. (United States)

    Macina, Simona; Mandolfino, Francesca; Frascio, Marco; Casaccia, Marco; Stabilini, Cesare; Fornaro, Rosario; Testa, Tommaso


    Parastomal hernia is one of the most common stoma related complication, with the correlated risk of incarceration, obstruction, and strangulation. The incidence is high (30-50%) and depends on the length of follow up. Different surgical options for repairing are defective with a 25-70% failure and recurrence rate. Prevention of parastomal hernia with mesh reinforcement seems to be effective. Three available trials are recruiting patients: Prism (with matrix porcine prothesis), Prevent (with preperitoneal polypropylene mesh), and the stapled polypropylene mesh stoma reinforcement technique (SMART). We performed the SMART procedure in six patients undergoing definitive colostomy. Our cases show that the procedure is rapid (duration range 15-20 minutes), cost effective (500 euro), and safe (in our experience, there are no post-surgical complications that are procedure-related). A long term follow-up and a higher number of patients will give us confirmation of the initial hopeful results.

  17. Transvaginal Excision of an Eroded Sacrocolpopexy Mesh by Using Single-Incision Laparoscopic Surgery Equipment. (United States)

    Mohr, Stefan; Siegenthaler, Franziska; Imboden, Sara; Kuhn, Annette; Mueller, Michael D

    To show a new technique of using single-incision laparoscopic surgery (SILS) equipment in vaginal surgery to create a "pneumovagina." Explanatory video demonstrating the technique and intraoperative findings. University hospital. The 68-year-old patient was referred with a vaginal mesh erosion that resulted in abscess formation at the vaginal apex. The patient was symptomatic with an increasingly foul-smelling vaginal discharge for about 1 year. She had a laparoscopic sacrocolpopexy in a remote hospital 22 months before the current operation and had a total abdominal hysterectomy 15 years ago. The, patient's history was uneventful without dyspareunia, incontinence or voiding difficulties, and she was otherwise content with the sacrocolpopexy result. The local institutional review board granted exemption for this publication. Frequently, pelvic organ prolapse can only be effectively treated if the surgical procedure comprises support of the central compartment. Laparoscopic sacrocolpopexy shows superior outcomes for this indication, with success rates of up to 96%. However, a rare side effect of laparoscopic sacrocolpopexy is mesh erosion, occurring in up to 2.4% [1]. These erosions are usually treated laparoscopically [2]. In this video we show an alternative route for excision of a symptomatic exposed mesh by using a transvaginal approach: The SILS trocar is used vaginally for abscess irrigation and mesh excision with minimally invasive instruments. For treatment of the abscess and removal of the exposed mesh, the SILS trocar was placed vaginally, and laparoscopic instruments were used. The abscess was incised, cleansed and irrigated, debrided, and the mesh excised. Because no mesh material was exposed after excision, the vagina was not closed to avoid creating a cavity with the risk of promoting reabscess formation, and secondary wound healing was anticipated. Laparoscopy was used to confirm that no intra-abdominal lesion coexisted or occurred. There were

  18. Vaginal Calculus in a Woman With Mixed Urinary Incontinence and Vaginal Mesh Exposure. (United States)

    Winkelman, William D; Rabban, Joseph T; Korn, Abner P


    Vaginal calculi are extremely rare and are most commonly encountered in the setting of an urethrovaginal or vesicovaginal fistula. We present a case of a 72-year-old woman with mixed urinary incontinence and vaginal mesh exposure incidentally found to have a large vaginal calculus. We removed the calculus surgically and analyzed the components. Results demonstrated the presence of ammonium-magnesium phosphate hexahydrate and carbonate apatite.

  19. Far infrared metal mesh filters and Fabry-Perot interferometry

    International Nuclear Information System (INIS)

    Kiyomi, S.; Genzel, L.


    The use of metal meshes is becoming increasingly important for applications in the far infrared. This paper reviews the important aspects of metal meshes, metal mesh filters, Fabry-Perot interferometers and their applications. The article includes the following: an introductory description and historical review of far-infrared metal meshes, the optical properties of metal meshes, beam splitters and filters based on inherent optical properties of meshes, Fabry-Perot interferometers, multimesh filters, applications of metal mesh filters and Fabry-Perot interferometers for far-infrared lasers, for plasma diagnostics and for astronomy

  20. An eFTD-VP framework for efficiently generating patient-specific anatomically detailed facial soft tissue FE mesh for craniomaxillofacial surgery simulation. (United States)

    Zhang, Xiaoyan; Kim, Daeseung; Shen, Shunyao; Yuan, Peng; Liu, Siting; Tang, Zhen; Zhang, Guangming; Zhou, Xiaobo; Gateno, Jaime; Liebschner, Michael A K; Xia, James J


    Accurate surgical planning and prediction of craniomaxillofacial surgery outcome requires simulation of soft tissue changes following osteotomy. This can only be achieved by using an anatomically detailed facial soft tissue model. The current state-of-the-art of model generation is not appropriate to clinical applications due to the time-intensive nature of manual segmentation and volumetric mesh generation. The conventional patient-specific finite element (FE) mesh generation methods are to deform a template FE mesh to match the shape of a patient based on registration. However, these methods commonly produce element distortion. Additionally, the mesh density for patients depends on that of the template model. It could not be adjusted to conduct mesh density sensitivity analysis. In this study, we propose a new framework of patient-specific facial soft tissue FE mesh generation. The goal of the developed method is to efficiently generate a high-quality patient-specific hexahedral FE mesh with adjustable mesh density while preserving the accuracy in anatomical structure correspondence. Our FE mesh is generated by eFace template deformation followed by volumetric parametrization. First, the patient-specific anatomically detailed facial soft tissue model (including skin, mucosa, and muscles) is generated by deforming an eFace template model. The adaptation of the eFace template model is achieved by using a hybrid landmark-based morphing and dense surface fitting approach followed by a thin-plate spline interpolation. Then, high-quality hexahedral mesh is constructed by using volumetric parameterization. The user can control the resolution of hexahedron mesh to best reflect clinicians' need. Our approach was validated using 30 patient models and 4 visible human datasets. The generated patient-specific FE mesh showed high surface matching accuracy, element quality, and internal structure matching accuracy. They can be directly and effectively used for clinical

  1. Investigation of superparamagnetic iron oxide nanoparticles for MR-visualization of surgical implants. (United States)

    Slabu, I; Guntherodt, G; Schmitz-Rode, T; Hodenius, M; Kramer, N; Donker, H; Krombach, G A; Otto, J; Klinge, U; Baumann, M


    For the development of a surgical mesh implant that is visible in magnetic resonance imaging (MRI), superparamagnetic iron oxides (SPIOs) are integrated into the material of the mesh. In order to get a high quality mesh regarding both mechanical and imaging properties, a narrow size distribution and homogenous spatial distribution, as well as a strong magnetization of SPIOs within the filament of the mesh are required. In this work, six different samples of SPIOs composed of a magnetite core are synthesized with and without stabilizing dodecanoic acid and analyzed using a superconducting quantum interference device (SQUID), transmission electron microscope (TEM) and a magnetic force microscope (MFM) to determine the properties that are beneficial for the assembly and imaging of the implant. These analyses show the feasibility of visualization of surgical implants with incorporated SPIOs and the influence of the agglomeration of SPIOs on their magnetization and on a homogenous spatial distribution within the polymer of the mesh.

  2. Biological Mesh Implants for Abdominal Hernia Repair: US Food and Drug Administration Approval Process and Systematic Review of Its Efficacy. (United States)

    Huerta, Sergio; Varshney, Anubodh; Patel, Prachi M; Mayo, Helen G; Livingston, Edward H


    Expensive biological mesh materials are increasingly used to reinforce abdominal wall hernia repairs. The clinical and cost benefit of these materials are unknown. To review the published evidence on the use of biological mesh materials and to examine the US Food and Drug Administration (FDA) approval history for these devices. Search of multiple electronic databases (Ovid, MEDLINE, EMBASE, Cochrane Systematic Reviews, Cochrane Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials, and Cochrane National Health Service Economic Evaluation Database) to identify articles published between 1948 and June 30, 2015, on the use of biological mesh materials used to reinforce abdominal wall hernia repair. Keywords searched included surgical mesh, abdominal hernia, recurrence, infection, fistula, bioprosthesis, biocompatible materials, absorbable implants, dermis, and collagen. The FDA online database for 510(k) clearances was reviewed for all commercially available biological mesh materials. The median national price for mesh materials was established by a benchmarking query through several Integrated Delivery Network and Group Purchasing Organization tools. Of 274 screened articles, 20 met the search criteria. Most were case series that reported results of convenience samples of patients at single institutions with a variety of clinical problems. Only 3 of the 20 were comparative studies. There were no randomized clinical trials. In total, outcomes for 1033 patients were described. Studies varied widely in follow-up time, operative technique, meshes used, and patient selection criteria. Reported outcomes and clinical outcomes, such as fistula formation and infection, were inconsistently reported across studies. Conflicts of interest were not reported in 16 of the 20 studies. Recurrence rates ranged from 0% to 80%. All biological mesh devices were approved by the FDA based on substantial equivalence to a group of nonbiological predicate

  3. Ultrasound appearances after mesh implantation-evidence of mesh contraction or folding?

    Czech Academy of Sciences Publication Activity Database

    Švabík, K.; Martan, A.; Mašata, J.; Haddad El, R.; Hubka, P.; Pavlíková, Markéta


    Roč. 22, č. 5 (2011), s. 529-533 ISSN 0937-3462 Grant - others:GA MZd(CZ) NR9216 Institutional research plan: CEZ:AV0Z10300504 Keywords : prolift anterior * mesh shrinking * mesh retraction * vaginal ultrasound * vaginal surgery Subject RIV: FK - Gynaecology, Childbirth Impact factor: 1.832, year: 2011

  4. Experimental study comparing the tensile strength of different surgical meshes following aponeurotic-muscle deformity synthesis on Wistar rats Estudo experimental comparando a resistência tênsil de diferentes tipos de telas cirúrgicas após síntese de defeito músculo-aponeurótico em ratos Wistar

    Directory of Open Access Journals (Sweden)

    Armando José d'Acampora


    Full Text Available PURPOSE: To assess the tensile strength of polypropylene and polypropylene associated with polyglactin meshes (Vypro II® - Ethicon®, Somerville, NJ, USA in a situation of partial separation of abdominal muscle aponeurosis on rats. METHODS: Thirty rats were used of the Wistar strain, which were randomized into two groups of 15 specimens each. In both groups an aponeurotic-muscle deformity was created on the abdominal wall measuring 3.0 x 1.0 cm, which was closed with polypropylene mesh (polypropylene group or Vypro® mesh (vypro group. After 28 days the rats underwent euthanasia and an area was removed from the abdominal wall with which a strip was made measuring 2.0 cm in length and 6.0 cm in width comprising the abdominal muscles with the implanted mesh. This sample was placed in a mechanical test machine in which a constant force was applied contrary to the tissue strips. Maximum force expressed in Newton was considered until full rupture of the sample occurred. The non-parametric Kruskal - Wallis test was used for statistical analysis admitting pOBJETIVO: Avaliar a resistência tênsil das telas de polipropileno e polipropileno associado à poliglactina (Vypro II® - Ethicon®, Somerville, NJ, USA em situação de afastamento parcial da aponeurose dos músculos abdominais em ratos. MÉTODOS: Foram utilizados trinta ratos da linhagem Wistar randomizados em dois grupos de quinze exemplares cada um. Em ambos os grupos criou-se um defeito músculo-aponeurótico na parede abdominal medindo 3,0 x 1,0 cm que foi fechado com tela de polipropileno (grupo polipropileno ou Vypro® (grupo vypro. Após 28 dias, foi feita a eutanásia e retirou-se uma área da parede abdominal com a qual fez-se uma tira medindo 2,0 cm de comprimento por 6,0 cm de largura englobando os músculos abdominais com a tela implantada. Essa amostra foi presa em máquina de ensaios mecânicos na qual se aplicou força constante contrária às tiras de tecido. Foi considerada a

  5. Selective laser vaporization of polypropylene mesh used in treatment of female stress urinary incontinence and pelvic organ prolapse: preliminary studies using a red diode laser. (United States)

    Burks, David; Rosenbury, Sarah B; Kennelly, Michael J; Fried, Nathaniel M


    The most common mesh-related complication experienced by patients undergoing transvaginal polypropylene synthetic slings for stress urinary incontinence (SUI) and transvaginal pelvic organ prolapse (POP) repair with mesh is vaginal mesh erosion. More than half of the patients who experience erosion from synthetic mesh require surgical excision which is technically challenging and risks damage to healthy adjacent tissue. This study explores selective laser vaporization of polypropylene suture/mesh materials commonly used in SUI and POP. A compact, 7 Watt, 647-nm, red diode laser was operated with a radiant exposure of 81 J/cm(2) , pulse duration of 100 milliseconds, and 1.0-mm-diameter laser spot. The 647-nm wavelength was selected because its absorption by water, hemoglobin, and other tissue chromophores is low, while polypropylene absorption is high. Laser vaporization of ∼200-µm-diameter polypropylene suture/mesh strands, in contact with fresh urinary tissue samples was performed, ex vivo. Temperature mapping of suture/mesh samples with a thermal camera was also conducted. Selective vaporization of polypropylene suture and mesh using a single laser pulse was achieved with peak temperatures of 180 and 232°C, respectively, while direct laser irradiation of tissue alone resulted in only a 1°C temperature increase. Selective laser vaporization of polypropylene suture/mesh materials is feasible without significant thermal elevation in the adjacent tissue. This technique may be useful for treatment of eroded mesh after SUI or POP procedures that require surgical revision. Copyright © 2012 Wiley Periodicals, Inc.

  6. Partial titanium mesh explantation cured post-cranioplasty implant-associated scalp infection. (United States)

    Chen, Bo; Li, Wenchen; Chen, Dawei; Fu, Shuanglin; Gao, Yanli; Li, Ri; Meng, Fanyang; Wang, Haifeng; Zhang, Shuyan


    Titanium mesh cranioplasty is routinely used worldwide for skull defect patients given its advantages, such as stability and biocompatibility. However, there are very few reports concerning the treatment of implant-associated scalp infection, which is one of the most common complications. The aim of the study is to retrospectively evaluate a novel operation technique for the treatment of titanium mesh-associated scalp infection post-cranioplasty, namely partial titanium mesh explantation (PTME). A retrospective study was conducted in all patients who underwent surgical treatment for implant-associated scalp infection from January 2012 to September 2016 in our hospital. In total, 17 patients were selected for study analysis among 231 patients who underwent cranioplasty. The treatment success rate of PTME was 85.7%. There was no statistically significant difference in demographics and characteristics except for follow-up length of time between the PTME group and TTME (total titanium mesh explantation) group (Non-paired Student's t-test, P=0.037). While, The PTME group exhibited a significantly reduced skull defect area post-operation compared with the TTME group (Non-paired Student's t-test, P=0.002). Moreover, post-PTME skull area also exhibited a significantly reduced skull defect area compared with the pre-cranioplasty area in the same patient (Non-paired Student's t-test, P=0.006). Compared with traditional surgical treatment of implant-associated scalp infection, PTME combined with strict debridement and antibiotic therapy can cure implant-associated scalp infection. Moreover, PTME could preserve sufficient titanium mesh for brain protection and cosmesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. An evaluation of hernia education in surgical residency programs. (United States)

    Hope, W W; O'Dwyer, B; Adams, A; Hooks, W B; Kotwall, C A; Clancy, T V


    The purpose of this study was to evaluate surgical residents' educational experience related to ventral hernias. A 16-question survey was sent to all program coordinators to distribute to their residents. Consent was obtained following a short introduction of the purpose of the survey. Comparisons based on training level were made using χ(2) test of independence, Fisher's exact, and Fisher's exact with Monte Carlo estimate as appropriate. A p value techniques for open ventral hernia varied; the most common (32 %) was intra-abdominal placement of mesh with defect closure. Twenty-two percent of residents had not heard of the retrorectus technique for hernia repair, 48 % had not performed the operation, and 60 % were somewhat comfortable with and knew the general categories of mesh prosthetics products. Mesh choices, biologic and synthetic, varied among the different products. The most common type of hernia education was teaching in the operating room in 87 %, didactic lecture 69 %, and discussion at journal club 45 %. Number of procedures, comfort level with open and laparoscopic techniques, indications for mesh use and technique, familiarity and use of retrorectus repair, and type of hernia education varied significantly based on resident level (p techniques and mesh prosthetics in surgical residency programs appears to vary. Further evaluation is needed and may help in standardizing curriculums for hernia repair for surgical residents.

  8. [Surgical approach and sexual outcomes after radical prostatectomy]. (United States)

    Caillet, K; Lipsker, A; Alezra, E; De Sousa, P; Pignot, G


    Radical prostatectomy is curative surgical treatment of choice for localized prostate cancer. The objectives are cancer control, preservation of continence and preservation of sexuality, the combination of the three constituting the Trifecta. The objective of this study was to assess, through the analysis of the literature, the sexual outcomes according to surgical approach: radical prostatectomy by laparotomy (PRL), laparoscopic radical prostatectomy (PRLa) and laparoscopic robot-assisted radical prostatectomy (PRLaRA), when nerve sparing was practiced. An exhaustive and retrospective review of literature was conducted using the Pubmed search with the following keywords: "Prostatic Neoplasms" [Mesh], "Prostatectomy" [Mesh], "Erectile Dysfunction" [Mesh], "Robotics" [Mesh], "Laparoscopy" [Mesh], Nerve sparing. The selected articles were prospective or retrospective series including more than 200 patients, randomized trials and meta-analyses published between 1990 and 2014. A total of 21 prospective studies (6 on PRL, 4 on PRLa and 11 on PRLaRA), 12 retrospective studies (6 on PRL, 1 on PRLa and 5 on PRLaRA), 2 randomized controlled trial and 3 meta-analyses were selected from 1992 to 2013. There was no evidence of the superiority of one surgical approach compared to others in terms of sexuality. Articles with level 1 of scientific evidence have discordant results, due to heterogeneity in the assessment criteria of postoperative sexual function. According to our knowledge, there is currently no difference in terms of sexual outcomes between PRL, PRLA and PRLaRA approaches. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  9. NASA Lewis Meshed VSAT Workshop meeting summary (United States)

    Ivancic, William


    NASA Lewis Research Center's Space Electronics Division (SED) hosted a workshop to address specific topics related to future meshed very small-aperture terminal (VSAT) satellite communications networks. The ideas generated by this workshop will help to identify potential markets and focus technology development within the commercial satellite communications industry and NASA. The workshop resulted in recommendations concerning these principal points of interest: the window of opportunity for a meshed VSAT system; system availability; ground terminal antenna sizes; recommended multifrequency for time division multiple access (TDMA) uplink; a packet switch design concept for narrowband; and fault tolerance design concepts. This report presents a summary of group presentations and discussion associated with the technological, economic, and operational issues of meshed VSAT architectures that utilize processing satellites.

  10. Connectivity editing for quad-dominant meshes

    KAUST Repository

    Peng, Chihan


    We propose a connectivity editing framework for quad-dominant meshes. In our framework, the user can edit the mesh connectivity to control the location, type, and number of irregular vertices (with more or fewer than four neighbors) and irregular faces (non-quads). We provide a theoretical analysis of the problem, discuss what edits are possible and impossible, and describe how to implement an editing framework that realizes all possible editing operations. In the results, we show example edits and illustrate the advantages and disadvantages of different strategies for quad-dominant mesh design. © 2013 The Author(s) Computer Graphics Forum © 2013 The Eurographics Association and John Wiley & Sons Ltd.

  11. Calculation of coherent synchrotron radiation using mesh

    Directory of Open Access Journals (Sweden)

    T. Agoh


    Full Text Available We develop a new method to simulate coherent synchrotron radiation numerically. It is based on the mesh calculation of the electromagnetic field in the frequency domain. We make an approximation in the Maxwell equation which allows a mesh size much larger than the relevant wavelength so that the computing time is tolerable. Using the equation, we can perform a mesh calculation of coherent synchrotron radiation in transient states with shielding effects by the vacuum chamber. The simulation results obtained by this method are compared with analytic solutions. Though, for the comparison with theories, we adopt simplifications such as longitudinal Gaussian distribution, zero-width transverse distribution, horizontal uniform bend, and a vacuum chamber with rectangular cross section, the method is applicable to general cases.

  12. The generation of hexahedral meshes for assembly geometries: A survey

    Energy Technology Data Exchange (ETDEWEB)



    The finite element method is being used today to model component assemblies in a wide variety of application areas, including structural mechanics, fluid simulations, and others. Generating hexahedral meshes for these assemblies usually requires the use of geometry decomposition, with different meshing algorithms applied to different regions. While the primary motivation for this approach remains the lack of an automatic, reliable all-hexahedral meshing algorithm, requirements in mesh quality and mesh configuration for typical analyses are also factors. For these reasons, this approach is also sometimes required when producing other types of unstructured meshes. This paper will review progress to date in automating many parts of the hex meshing process, which has halved the time to produce all-hex meshes for large assemblies. Particular issues which have been exposed due to this progress will also be discussed, along with their applicability to the general unstructured meshing problem.

  13. Mesh control information of windmill designed by Solidwork program (United States)

    Mulyana, T.; Sebayang, D.; Rafsanjani, A. M. D.; Adani, J. H. D.; Muhyiddin, Y. S.


    This paper presents the mesh control information imposed on the windmill already designed. The accuracy of Simulation results is influenced by the quality of the created mesh. However, compared to the quality of the mesh is made, the simulation time running will be done software also increases. The smaller the size of the elements created when making the mesh, the better the mesh quality will be generated. When adjusting the mesh size, there is a slider that acts as the density regulator of the element. SolidWorks Simulation also has Mesh Control facility. Features that can adjust mesh density only in the desired part. The best results of mesh control obtained for both static and thermal simulation have ratio 1.5.

  14. MUSIC: a mesh-unrestricted simulation code

    International Nuclear Information System (INIS)

    Bonalumi, R.A.; Rouben, B.; Dastur, A.R.; Dondale, C.S.; Li, H.Y.H.


    A general formalism to solve the G-group neutron diffusion equation is described. The G-group flux is represented by complementing an ''asymptotic'' mode with (G-1) ''transient'' modes. A particular reduction-to-one-group technique gives a high computational efficiency. MUSIC, a 2-group code using the above formalism, is presented. MUSIC is demonstrated on a fine-mesh calculation and on 2 coarse-mesh core calculations: a heavy-water reactor (HWR) problem and the 2-D lightwater reactor (LWR) IAEA benchmark. Comparison is made to finite-difference results

  15. Unstructured Adaptive Meshes: Bad for Your Memory? (United States)

    Biswas, Rupak; Feng, Hui-Yu; VanderWijngaart, Rob


    This viewgraph presentation explores the need for a NASA Advanced Supercomputing (NAS) parallel benchmark for problems with irregular dynamical memory access. This benchmark is important and necessary because: 1) Problems with localized error source benefit from adaptive nonuniform meshes; 2) Certain machines perform poorly on such problems; 3) Parallel implementation may provide further performance improvement but is difficult. Some examples of problems which use irregular dynamical memory access include: 1) Heat transfer problem; 2) Heat source term; 3) Spectral element method; 4) Base functions; 5) Elemental discrete equations; 6) Global discrete equations. Nonconforming Mesh and Mortar Element Method are covered in greater detail in this presentation.

  16. Local adaptive mesh refinement for shock hydrodynamics

    International Nuclear Information System (INIS)

    Berger, M.J.; Colella, P.; Lawrence Livermore Laboratory, Livermore, 94550 California)


    The aim of this work is the development of an automatic, adaptive mesh refinement strategy for solving hyperbolic conservation laws in two dimensions. There are two main difficulties in doing this. The first problem is due to the presence of discontinuities in the solution and the effect on them of discontinuities in the mesh. The second problem is how to organize the algorithm to minimize memory and CPU overhead. This is an important consideration and will continue to be important as more sophisticated algorithms that use data structures other than arrays are developed for use on vector and parallel computers. copyright 1989 Academic Press, Inc

  17. Adaptive mesh refinement for storm surge

    KAUST Repository

    Mandli, Kyle T.


    An approach to utilizing adaptive mesh refinement algorithms for storm surge modeling is proposed. Currently numerical models exist that can resolve the details of coastal regions but are often too costly to be run in an ensemble forecasting framework without significant computing resources. The application of adaptive mesh refinement algorithms substantially lowers the computational cost of a storm surge model run while retaining much of the desired coastal resolution. The approach presented is implemented in the GeoClaw framework and compared to ADCIRC for Hurricane Ike along with observed tide gauge data and the computational cost of each model run. © 2014 Elsevier Ltd.

  18. Repair of large frontal temporal parietal skull defect with digitally reconstructed titanium mesh: a report of 20 cases

    Directory of Open Access Journals (Sweden)

    Gang-ge CHENG


    Full Text Available Objective To explore the clinical effect and surgical technique of the repair of large defect involving frontal, temporal, and parietal regions using digitally reconstructed titanium mesh. Methods Twenty patients with large frontal, temporal, and parietal skull defect hospitalized in Air Force General Hospital from November 2006 to May 2012 were involved in this study. In these 20 patients, there were 13 males and 7 females, aged 18-58 years (mean 39 years, and the defect size measured from 7.0cm×9.0cm to 11.5cm×14.0cm (mean 8.5cm×12.0cm. Spiral CT head scan and digital three-dimensional reconstruction of skull were performed in all the patients. The shape and geometric size of skull defect was traced based on the symmetry principle, and then the data were transferred into digital precision lathe to reconstruct a titanium mesh slightly larger (1.0-1.5cm than the skull defect, and the finally the prosthesis was perfected after pruning the border. Cranioplasty was performed 6-12 months after craniotomy using the digitally reconstructed titanium mesh. Results The digitally reconstructed titanium mesh was used in 20 patients with large frontal, temporal, parietal skull defect. The surgical technique was relatively simple, and the surgical duration was shorter than before. The titanium mesh fit to the defect of skull accurately with satisfactory molding effect, good appearance and symmetrical in shape. No related complication was found in all the patients. Conclusion Repair of large frontal, temporal, parietal skull defect with digitally reconstructed titanium mesh is more advantageous than traditional manual reconstruction, and it can improve the life quality of patients.

  19. Properties of meshes used in hernia repair: a comprehensive review of synthetic and biologic meshes. (United States)

    Ibrahim, Ahmed M S; Vargas, Christina R; Colakoglu, Salih; Nguyen, John T; Lin, Samuel J; Lee, Bernard T


    Data on the mechanical properties of the adult human abdominal wall have been difficult to obtain rendering manufacture of the ideal mesh for ventral hernia repair a challenge. An ideal mesh would need to exhibit greater biomechanical strength and elasticity than that of the abdominal wall. The aim of this study is to quantitatively compare the biomechanical properties of the most commonly used synthetic and biologic meshes in ventral hernia repair and presents a comprehensive literature review. A narrative review of the literature was performed using the PubMed database spanning articles from 1982 to 2012 including a review of company Web sites to identify all available information relating to the biomechanical properties of various synthetic and biologic meshes used in ventral hernia repair. There exist differences in the mechanical properties and the chemical nature of different meshes. In general, most synthetic materials have greater stiffness and elasticity than what is required for abdominal wall reconstruction; however, each exhibits unique properties that may be beneficial for clinical use. On the contrary, biologic meshes are more elastic but less stiff and with a lower tensile strength than their synthetic counterparts. The current standard of practice for the treatment of ventral hernias is the use of permanent synthetic mesh material. Recently, biologic meshes have become more frequently used. Most meshes exhibit biomechanical properties over the known abdominal wall thresholds. Augmenting strength requires increasing amounts of material contributing to more stiffness and foreign body reaction, which is not necessarily an advantage. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  20. One-year outcome of biological and synthetic bioabsorbable meshes for augmentation of large abdominal wall defects in a rabbit model. (United States)

    Peeters, Ellen; van Barneveld, Kevin W Y; Schreinemacher, Marc H; De Hertogh, Gert; Ozog, Yves; Bouvy, Nicole; Miserez, Marc


    Long-term efficacy of biological and synthetic bioabsorbable meshes for large hernia repair is currently unclear. This rabbit study is aimed at investigating 1-y outcome of biological and synthetic bioabsorbable meshes for augmentation of large abdominal wall defects. In 46 rabbits, an 11 × 4 cm, full-thickness abdominal wall defect was repaired primarily, or with cross-linked (Permacol, Collamend) or non-cross-linked (Surgisis 4-ply, Surgisis Biodesign) biological, synthetic bioabsorbable (GORE BIO-A Tissue Reinforcement [TR], TIGR Matrix Surgical Mesh [MSM]), or polypropylene (Bard Mesh) meshes, using the underlay augmentation technique. One year after surgery, primary outcome was recurrence; secondary outcomes were tensile strength, histologic degree of tissue remodeling, and intraabdominal adhesion formation. Only two Surgisis 4-ply animals (50%) presented with a recurrent hernia. All GORE BIO-A TR meshes were completely resorbed and, as after primary repair, well-organized connective tissue without inflammation was present, with moderate adhesion formation and sufficient tensile strength. Cross-linked biological and TIGR MSM meshes demonstrated highest tensile strength but were only partially incorporated, with similar foreign body reaction and adhesion formation as polypropylene meshes in the TIGR MSM group, and minimal degradation and moderate adhesion formation in the cross-linked biological group. In the non-cross-linked biological group sufficient tensile strength and moderate adhesion formation were found, with pronounced inflammation if mesh remnants were present. Synthetic bioabsorbable GORE BIO-A TR meshes were associated with optimal tissue remodeling, with complete resorption, presence of well-organized tissue, and no inflammation. However, mesh augmentation had no advantages regarding recurrence rate versus primary repair of large abdominal wall defects. Copyright © 2013 Elsevier Inc. All rights reserved.


    African Journals Online (AJOL)

    SURGICAL ANATOMY. Rare high origin of the radial artery: a bilateral, symmetrical ease. I. O. ()koro and B. C. J iburum. Department of Anatomy, College of Medicine, lrno State University, Owerri, Nigeria. Reprint requests to: Dr I. O. 0k0r0, Department of Anatomy, [mo State University, P. M. B. 2000. Owerri, Nigeria.


    African Journals Online (AJOL)

    Conclusion:Foraminotomy with or without discectomy is a simple posterior surgical approach to T B spine with good neurological outcome. It is adapted to our ... of the spine also referred to as. (HIV/AIDS) further challenge the outcome. These .... treatment; or for spinal cord or nerve root from 2 weeks depending on patient ...

  3. First human use of hybrid synthetic/biologic mesh in ventral hernia repair: a multicenter trial. (United States)

    Bittner, James G; El-Hayek, Kevin; Strong, Andrew T; LaPinska, Melissa Phillips; Yoo, Jin S; Pauli, Eric M; Kroh, Matthew


    Mesh options for reinforcement of ventral/incisional hernia (VIH) repair include synthetic or biologic materials. While each material has known advantages and disadvantages, little is understood about outcomes when these materials are used in combination. This multicenter study reports on the first human use of a novel synthetic/biologic hybrid mesh (Zenapro ® Hybrid Hernia Repair Device) for VIH repair. This prospective, multicenter post-market clinical trial enrolled consecutive adults who underwent elective VIH repair with hybrid mesh placed in the intraperitoneal or retromuscular/preperitoneal position. Patients were classified as Ventral Hernia Working Group (VHWG) grades 1-3 and had clean or clean-contaminated wounds. Outcomes of ventral and incisional hernia were compared using appropriate parametric tests. In all, 63 patients underwent VIH repair with hybrid mesh. Most were females (54.0%), had a mean age of 54.8 ± 10.9 years and mean body mass index of 34.5 ± 7.8 kg/m 2 , and classified as VHWG grade 2 (87.3%). Most defects were midline (92.1%) with a mean area of 106 ± 155 cm 2 . Cases were commonly classified as clean (92.1%) and were performed laparoscopically (60.3%). Primary fascial closure was achieved in 82.5% with 28.2% requiring component separation. Mesh location was frequently intraperitoneal (69.8%). Overall, 39% of patients available for follow-up at 12 months suffered surgical site events, which were generally more frequent after incisional hernia repair. Of these, seroma (23.7%) was most common, but few (8.5%) required procedural intervention. Other surgical site events that required procedural intervention included hematoma (1.7%), wound dehiscence (1.7%), and surgical site infection (3.4%). Recurrence rate was 6.8% (95% CI 2.2-16.6%) at 12-months postoperatively. Zenapro ® Hybrid Hernia Repair Device is safe and effective in VHWG grade 1-2 patients with clean wounds out to 12 months. Short-term outcomes and recurrence rate

  4. Highly Symmetric and Congruently Tiled Meshes for Shells and Domes (United States)

    Rasheed, Muhibur; Bajaj, Chandrajit


    We describe the generation of all possible shell and dome shapes that can be uniquely meshed (tiled) using a single type of mesh face (tile), and following a single meshing (tiling) rule that governs the mesh (tile) arrangement with maximal vertex, edge and face symmetries. Such tiling arrangements or congruently tiled meshed shapes, are frequently found in chemical forms (fullerenes or Bucky balls, crystals, quasi-crystals, virus nano shells or capsids), and synthetic shapes (cages, sports domes, modern architectural facades). Congruently tiled meshes are both aesthetic and complete, as they support maximal mesh symmetries with minimal complexity and possess simple generation rules. Here, we generate congruent tilings and meshed shape layouts that satisfy these optimality conditions. Further, the congruent meshes are uniquely mappable to an almost regular 3D polyhedron (or its dual polyhedron) and which exhibits face-transitive (and edge-transitive) congruency with at most two types of vertices (each type transitive to the other). The family of all such congruently meshed polyhedra create a new class of meshed shapes, beyond the well-studied regular, semi-regular and quasi-regular classes, and their duals (platonic, Catalan and Johnson). While our new mesh class is infinite, we prove that there exists a unique mesh parametrization, where each member of the class can be represented by two integer lattice variables, and moreover efficiently constructable. PMID:27563368

  5. In vitro degradation and in vivo biocompatibility of poly(lactic acid) mesh for soft tissue reinforcement in vaginal surgery. (United States)

    de Tayrac, Renaud; Chentouf, Samir; Garreau, Henri; Braud, Christian; Guiraud, Isabelle; Boudeville, Philippe; Vert, Michel


    This study was aimed at evaluating the in vitro degradation, the in vivo biocompatibility and at comparing the effects of two methods of sterilization on poly(L-lactic acid) (PLA(94)) resorbable mesh. The mesh was manufactured to be used as surgical soft tissue reinforcement in the vaginal area. Samples of 100 mg of PLA(94) mesh (10 x 10 mm(2)) were immersed in isoosmolar 0.13M, pH 7.4 phosphate buffer solution at 37 degrees C, during 12 months. The hydrolytic degradation up to 12 months after immersion was monitored by measuring weight loss, mesh area changes, and by various analytical techniques namely Differential scanning calorimetry (DSC), capillary zone electrophoresis (CZE), size exclusion chromatography (SEC), and environmental scanning electron microscopy (ESEM). Specimens of nonsterilized, ethylene-oxide (ETO) sterilized, and gamma-ray sterilized PLA(94) mesh were compared. Fifteen samples were implanted in an incisional hernia Wistar rat model. Histopathology was performed up to 90 days after implantation to evaluate the inflammatory response and the collagen deposition. Although the decrease of molecular weight due to polymer chain scissions started 6 weeks after in vitro immersion, water-soluble degradation products and decrease of tensile strength appeared after 8 months only. Analyses showed also that ETO sterilization did not affect the degradation of the PLA(94) mesh. In contrast, gamma-ray sterilization increased very much the sensitivity of the mesh to the hydrolytic degradation. In vivo, the PLA(94) mesh exhibited good biocompatibility over the investigated time period. Copyright 2007 Wiley Periodicals, Inc.

  6. The use of PROCEED mesh in ventral hernias: A pilot study on 22 cases

    Directory of Open Access Journals (Sweden)

    Almoutaz A Eltayeb


    Full Text Available Background: The management of major omphalocoele and large incisional hernias is a common problem and constitutes a great challenge for paediatric surgeons. In most cases, the abdominal cavity is so small and does not allow immediate reduction. Prosthetic materials are becoming increasingly popular for such repair, but direct contact between the bowel and these synthetic materials carries the risk of adhesions and intestinal obstruction. The relatively new PROCEED mesh with absorbable layer in contact with the bowel and another polypropylene non-absorbable layer against the abdominal wall may not produce such adhesions. The aim of this study is to evaluate the feasibility and outcome of this relatively new prosthetic mesh for repair of ventral hernia . Patients and Methods: Between June 2009 and December 2012, a pilot study was conducted on 22 cases with large ventral hernias subjected to open surgical repair using PROCEED mesh. The inclusion criterion was cases with large ventral hernias (>4 cm. The evaluating parameters were all the early and late postoperative complications. Results: The defect size ranged from 5 to 12 cm. The early postoperative complication (≤1 month was seroma discharged from the wound in four cases, while the late complications were recurrent herniation and stitch sinus that occurred in three cases. No manifestations of intestinal obstruction, enterocutaneous fistula or mortality were encountered in any of the 22 cases. Conclusion: The use of PROCEED composite mesh in ventral hernias is feasible and has minimal complication rates.

  7. Treatment of Mesh Skin Grafted Scars Using a Plasma Skin Regeneration System

    Directory of Open Access Journals (Sweden)

    Takamitsu Higashimori


    Full Text Available Objectives. Several modalities have been advocated to treat traumatic scars, including surgical techniques and laser resurfacing. Recently, a plasma skin regeneration (PSR system has been investigated. There are no reports on plasma treatment of mesh skin grafted scars. The objective of our study is to evaluate the effectiveness and complications of plasma treatment of mesh skin grafted scars in Asian patients. Materials and Methods. Four Asian patients with mesh skin grafted scars were enrolled in the study. The plasma treatments were performed at monthly intervals with PSR, using energy settings of 3 to 4 J. Improvement was determined by patient questionnaires and physician evaluation of digital photographs taken prior to treatment and at 3 months post treatment. The patients were also evaluated for any side effects from the treatment. Results. All patients showed more than 50% improvement. The average pain score on a 10-point scale was 6.9 +/− 1.2 SD and all patients tolerated the treatments. Temporary, localized hypopigmentation was observed in two patients. Hyperpigmentation and worsening of scarring were not observed. Conclusions. Plasma treatment is clinically effective and is associated with minimal complications when used to treat mesh skin grafted scars in Asian patients.

  8. Postoperative complications of mesh hernioplasty for incisional hernia repair and factors affecting the occurrence of complications

    Directory of Open Access Journals (Sweden)

    Karan Vir Singh Rana


    Full Text Available Context: Incisional hernia is one of the common postoperative complications of abdominal surgery. Mesh hernioplasty represents the standard of care for incisional hernia repair. Aims: We report our experience with the use of mesh for hernia repair, with respect to the postoperative complications and factors affecting the occurrence of complications. Settings and Design: Fifty four cases of incisional hernia presenting to the institute between April 2008 and September 2010 were included in the study. Materials and Methods: The predisposing risk factors were identified. Mesh hernioplasty was done by the onlay technique and the patients followed up for at least 6 months. Statistical Analysis Used: An association of complications with various risk factors was explored with chi-square test and odds ratio with 95% confidence interval. Results: Twenty four patients developed at least one complication, the most common being seroma (12 cases and surgical site infection (9 cases. The factors that showed a significant relationship with the occurrence of complications were diabetes mellitus, obesity, smoking, hypoproteinemia, advanced age, size of fascial defects, and number of defects. The recurrence rate was 3.7% (mean follow up: 13.05 months. Conclusions: Mesh hernioplasty gives acceptable results for incisional hernia repair. A sound understanding of the factors affecting the occurrence of complications and recurrence is required to improve the results of the procedure.

  9. MESH Release 2 implementation at CTIT

    NARCIS (Netherlands)

    Diakov, N.K.; van Sinderen, Marten J.; Koprinkov, G.T.

    This document contains a description of the development done at CTIT on the MESH services platform, a TINA-based platform for the deployment and exploitation of services to support teamwork. It provides an overview of the results and the usability of architectural solutions and technologies used

  10. Markov Random Fields on Triangle Meshes

    DEFF Research Database (Denmark)

    Andersen, Vedrana; Aanæs, Henrik; Bærentzen, Jakob Andreas


    In this paper we propose a novel anisotropic smoothing scheme based on Markov Random Fields (MRF). Our scheme is formulated as two coupled processes. A vertex process is used to smooth the mesh by displacing the vertices according to a MRF smoothness prior, while an independent edge process labels...

  11. Oxidation and degradation of polypropylene transvaginal mesh. (United States)

    Talley, Anne D; Rogers, Bridget R; Iakovlev, Vladimir; Dunn, Russell F; Guelcher, Scott A


    Polypropylene (PP) transvaginal mesh (TVM) repair for stress urinary incontinence (SUI) has shown promising short-term objective cure rates. However, life-altering complications have been associated with the placement of PP mesh for SUI repair. PP degradation as a result of the foreign body reaction (FBR) has been proposed as a contributing factor to mesh complications. We hypothesized that PP oxidizes under in vitro conditions simulating the FBR, resulting in degradation of the PP. Three PP mid-urethral slings from two commercial manufacturers were evaluated. Test specimens (n = 6) were incubated in oxidative medium for up to 5 weeks. Oxidation was assessed by Fourier Transform Infrared Spectroscopy (FTIR), and degradation was evaluated by scanning electron microscopy (SEM). FTIR spectra of the slings revealed evidence of carbonyl and hydroxyl peaks after 5 weeks of incubation time, providing evidence of oxidation of PP. SEM images at 5 weeks showed evidence of surface degradation, including pitting and flaking. Thus, oxidation and degradation of PP pelvic mesh were evidenced by chemical and physical changes under simulated in vivo conditions. To assess changes in PP surface chemistry in vivo, fibers were recovered from PP mesh explanted from a single patient without formalin fixation, untreated (n = 5) or scraped (n = 5) to remove tissue, and analyzed by X-ray photoelectron spectroscopy. Mechanical scraping removed adherent tissue, revealing an underlying layer of oxidized PP. These findings underscore the need for further research into the relative contribution of oxidative degradation to complications associated with PP-based TVM devices in larger cohorts of patients.


    Directory of Open Access Journals (Sweden)

    Geeta Vandana Reddi


    Full Text Available BACKGROUND Pelvic organ prolapse is a common complaint in gynaecological practice. Nulliparous prolapse is seen in 2% of female population and vault prolapse in 0.5% following hysterectomy. Various surgical procedures have been described for the repair of vault prolapse e.g. transvaginal sacrospinous colpopexy, transabdominal sacral colpopexy, Le Forte's operation, colpoclesis, posterior intravaginal sling plasty etc. The introduction of synthetic mesh like Prolene, Mersilene for the repair of vault prolapse have the advantage of tensile strength. In nulliparous prolapse and uterovaginal prolapse also, the supports of uterus are weakened, so there seems to be a definite advantage of mesh repair over sling surgeries. MATERIALS AND METHODS A prospective study done in 50 patients with vault prolapse, Nulliparous prolapse and patients with UV prolapse who want to retain their menstrual and reproductive function were identified and repair of defects were done. 2 cases who underwent both hysterectomy and sacral colpopexy in two sittings were included in the study. They were followed up for a period of 6 weeks - 29 months. RESULTS In the present study, the mean age for vault prolapse was 52.14 years, mean parity was 3.36. Vault prolapses were found to be more common after abdominal hysterectomy 60.97% compared to vaginal 39.02%. Common indication for hysterectomy is pelvic organ prolapse followed by DUB in this study. The mean time between the hysterectomy and vault prolapse in this study was 5.46 years. Importance should be given to proper enterocoele repair and vault suspense time of primary surgery. In this study incidence of smoking in vault prolapse cases was 34.14% significant. In cases of sacral colpopexy for vault prolapse in this study there were no major mesh related complications and the cure rate was 97.5%. So, sacral colpopexy with prolene mesh i.e. abdominal mesh repair can be employed as the primary surgery for vault prolapse. The safety

  13. Initial Experience with a New Macroporous Partially Absorbable Mesh: Introducing Ultrapro® Advanced™. (United States)

    Handojo, Karen; Meylemans, Diederik; Devroe, Kurt; Vermeiren, Koen; Aelvoet, Chris; Tollens, Tim


    due to incorporation of evidence-based characteristics such as an increased mesh elasticity. Furthermore, the surgical manipulation is improved thanks to the increased mesh memory. Our prospective cohort study shows good initial and short-term results after implementation of the Ultrapro® Advanced™. However, further prospective research is mandatory on the long-term outcomes.

  14. A Fully Automated Mesh Generation Tool, Phase I (United States)

    National Aeronautics and Space Administration — This SBIR Phase I project proposes to develop a fully automated mesh generation tool which contains two parts: surface mesh generation from the imported Computer...

  15. Jali - Unstructured Mesh Infrastructure for Multi-Physics Applications

    Energy Technology Data Exchange (ETDEWEB)


    Jali is a parallel unstructured mesh infrastructure library designed for use by multi-physics simulations. It supports 2D and 3D arbitrary polyhedral meshes distributed over hundreds to thousands of nodes. Jali can read write Exodus II meshes along with fields and sets on the mesh and support for other formats is partially implemented or is (, an open source general purpose unstructured mesh infrastructure library from Los Alamos National Laboratory. While it has been made to work with other mesh frameworks such as MOAB and STKmesh in the past, support for maintaining the interface to these frameworks has been suspended for now. Jali supports distributed as well as on-node parallelism. Support of on-node parallelism is through direct use of the the mesh in multi-threaded constructs or through the use of "tiles" which are submeshes or sub-partitions of a partition destined for a compute node.

  16. CUBIT mesh generation environment. Volume 1: Users manual

    Energy Technology Data Exchange (ETDEWEB)

    Blacker, T.D.; Bohnhoff, W.J.; Edwards, T.L. [and others


    The CUBIT mesh generation environment is a two- and three-dimensional finite element mesh generation tool which is being developed to pursue the goal of robust and unattended mesh generation--effectively automating the generation of quadrilateral and hexahedral elements. It is a solid-modeler based preprocessor that meshes volume and surface solid models for finite element analysis. A combination of techniques including paving, mapping, sweeping, and various other algorithms being developed are available for discretizing the geometry into a finite element mesh. CUBIT also features boundary layer meshing specifically designed for fluid flow problems. Boundary conditions can be applied to the mesh through the geometry and appropriate files for analysis generated. CUBIT is specifically designed to reduce the time required to create all-quadrilateral and all-hexahedral meshes. This manual is designed to serve as a reference and guide to creating finite element models in the CUBIT environment.

  17. Surgical Navigation

    DEFF Research Database (Denmark)

    Azarmehr, Iman; Stokbro, Kasper; Bell, R. Bryan


    body removal, respectively. The average technical system accuracy and intraoperative precision reported were less than 1 mm and 1 to 2 mm, respectively. In general, SN is reported to be a useful tool for surgical planning, execution, evaluation, and research. The largest numbers of studies and patients......Purpose: This systematic review investigates the most common indications, treatments, and outcomes of surgical navigation (SN) published from 2010 to 2015. The evolution of SN and its application in oral and maxillofacial surgery have rapidly developed over recent years, and therapeutic indications...... surgery, skull-base surgery, and foreign body removal were the areas of interests. Results: The search generated 13 articles dealing with traumatology; 5, 6, 2, and 0 studies were found that dealt with the topics of orthognathic surgery, cancer and reconstruction surgery, skull-base surgery, and foreign...

  18. Sewing machine technique for laparoscopic mesh fixation in intra-peritoneal on-lay mesh. (United States)

    Dastoor, Khojasteh Sam; Balsara, Kaiomarz P; Gazi, Asif Y


    : Mesh fixation in laparoscopic ventral hernia is accomplished using tacks or tacks with transfascial sutures. This is a painful operation and the pain is believed to be more due to transfascial sutures. We describe a method of transfascial suturing which fixes the mesh securely and probably causes less pain. : Up to six ports may be necessary, three on each side. A suitable-sized mesh is used and fixed with tacks all around. A 20G spinal needle is passed from the skin through one corner of the mesh. A 0 prolene suture is passed through into the peritoneum. With the prolene within, the needle is withdrawn above the anterior rectus sheath and passed again at an angle into the abdomen just outside the mesh. A loop of prolene is thus created which is tied under vision using intra-corporeal knotting. : This method gives a secure mesh fixation and causes less pain than conventional methods. This technique is easy to learn but needs expertise in intra-corporeal knotting.

  19. On Reducing Delay in Mesh-Based P2P Streaming: A Mesh-Push Approach (United States)

    Liu, Zheng; Xue, Kaiping; Hong, Peilin

    The peer-assisted streaming paradigm has been widely employed to distribute live video data on the internet recently. In general, the mesh-based pull approach is more robust and efficient than the tree-based push approach. However, pull protocol brings about longer streaming delay, which is caused by the handshaking process of advertising buffer map message, sending request message and scheduling of the data block. In this paper, we propose a new approach, mesh-push, to address this issue. Different from the traditional pull approach, mesh-push implements block scheduling algorithm at sender side, where the block transmission is initiated by the sender rather than by the receiver. We first formulate the optimal upload bandwidth utilization problem, then present the mesh-push approach, in which a token protocol is designed to avoid block redundancy; a min-cost flow model is employed to derive the optimal scheduling for the push peer; and a push peer selection algorithm is introduced to reduce control overhead. Finally, we evaluate mesh-push through simulation, the results of which show mesh-push outperforms the pull scheduling in streaming delay, and achieves comparable delivery ratio at the same time.

  20. 21 CFR 870.3650 - Pacemaker polymeric mesh bag. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold a...

  1. Cryo-mesh: a simple alternative cryopreservation protocol. (United States)

    Funnekotter, B; Bunn, E; Mancera, R L

    The continued development of new cryopreservation protocols has improved post-cryogenic success rates for a wide variety of plant species. Methods like the cryo-plate have proven beneficial in simplifying the cryopreservation procedure. This study assessed the practicality of a stainless steel mesh strip (cryo-mesh) for cryopreserving shoot tips from Anigozanthos viridis. Shoot tips of A. viridis (Kangaroo Paw) were precultured on 0.4 M sucrose medium for 48 h. Precultured shoot tips were coated in a 2% alginate solution and placed onto the cryo-mesh (a 25 x 7 mm, 0.4 mm aperture, 0.224 mm diameter wire stainless steel mesh strip). The alginate was set for 20 min in a loading solution containing 100 mM CaCl2, anchoring the shoot tips to the cryo-mesh. The cryo-mesh was then transferred to PVS2 on ice for 20, 30 or 40 min prior to plunging the cryo-mesh into liquid nitrogen. The cryo-mesh protocol was compared to the droplet-vitrification protocol. A maximum of 83% post-cryogenic regeneration was achieved with the cryo-mesh when exposed to PVS2 for 30 min. No significant difference in post-cryogenic regeneration was observed between the cryo-mesh and droplet-vitrification protocols. Anigozanthos viridis shoot tips were successfully cryopreserved utilising the new cryo-mesh. The cryo-mesh thus provides a simple and successful alternative for cryopreservation.

  2. Cache-mesh, a Dynamics Data Structure for Performance Optimization

    DEFF Research Database (Denmark)

    Nguyen, Tuan T.; Dahl, Vedrana Andersen; Bærentzen, J. Andreas


    This paper proposes the cache-mesh, a dynamic mesh data structure in 3D that allows modifications of stored topological relations effortlessly. The cache-mesh can adapt to arbitrary problems and provide fast retrieval to the most-referred-to topological relations. This adaptation requires trivial...

  3. Multiphase Flow of Immiscible Fluids on Unstructured Moving Meshes

    DEFF Research Database (Denmark)

    Misztal, Marek Krzysztof; Erleben, Kenny; Bargteil, Adam


    In this paper, we present a method for animating multiphase flow of immiscible fluids using unstructured moving meshes. Our underlying discretization is an unstructured tetrahedral mesh, the deformable simplicial complex (DSC), that moves with the flow in a Lagrangian manner. Mesh optimization op...

  4. Chest wall and hemidiaphragm reconstruction with Gore-Tex mesh and omolateral latissimus dorsi flap. A case report. (United States)

    Benzo, L; Datta, G; Pau, S; Oliaro, E; Mossetti, C; Ruffini, E; Filosso, P L; Cristofori, R; Oliaro, A


    There are various method of reconstruction when chest wall resection is performed for the treatment of tumors of the chest wall. In this case a chest wall resection and reconstruction was performed using an omolateral latissimus dorsi flap, together with Gore-Tex mesh. A 42-year-old woman was diagnosed as having a huge low grade chondrosarcoma and underwent surgical resection which interested the anterior chest wall from the level of the IV to X rib and the right hemidiaphragm. Gore-Tex mesh was fixed to the residual chest wall and an ipsilateral pedicled latissimus dorsi muscle flap was placed on the alloplastic mesh. The patient was discharged from the hospital 17 days postoperatively. The postoperative course was uneventful and the wound was fine.

  5. CAD-CAM prosthetically guided bone regeneration using preformed titanium mesh for the reconstruction of atrophic maxillary arches. (United States)

    Ciocca, L; Fantini, M; De Crescenzio, F; Corinaldesi, G; Scotti, R


    The protocol presented here is intended to minimise the intervention in bone reconstruction surgery when severe atrophy or deformity is present in the maxillary arches. A patient underwent augmentation of an atrophic maxillary arch using titanium mesh and particulate autogenous plus bovine demineralised bone. After computed tomography data elaboration, computer-aided design and computer-aided machining were used to plan the augmentation of bone volume to improve the implant position needed to support the final dental prosthesis. The augmented maxilla was rapidly prototyped in plastic, and the titanium mesh was tested on this model before the surgical intervention. Then, the preformed titanium mesh was implanted in the maxillary arch with bone grafting. The bone was augmented relative to the position of the implants for the definitive fixed implant-supported rehabilitation. The protocol presented here is a viable, reproducible way to determine the correct bone augmentation for the final implant-supported prosthetic rehabilitation.

  6. Evaluation of a fully absorbable poly-4-hydroxybutyrate/absorbable barrier composite mesh in a porcine model of ventral hernia repair. (United States)

    Scott, Jeffrey R; Deeken, Corey R; Martindale, Robert G; Rosen, Michael J


    The objective of this study was to evaluate the mechanical and histological properties of a fully absorbable poly-4-hydroxybutyrate/absorbable barrier composite mesh (Phasix™ ST) compared to partially absorbable (Ventralight™ ST), fully absorbable (Phasix™), and biologically derived (Strattice™) meshes in a porcine model of ventral hernia repair. Bilateral abdominal surgical defects were created in twenty-four Yucatan pigs, repaired with intraperitoneal (Phasix™ ST, Ventralight™ ST) or retromuscular (Phasix™, Strattice™) mesh, and evaluated at 12 and 24 weeks (n = 6 mesh/group/time point). Prior to implantation, Strattice™ demonstrated significantly higher (p weeks, mesh/repair strength was significantly greater than NAW (p weeks (p > 0.05). Phasix™ mesh/repair strength was significantly greater than Strattice™ (p weeks, and Ventralight™ ST mesh/repair strength was significantly greater than Phasix™ ST mesh (p weeks. At 12 and 24 weeks, Phasix™ ST and Ventralight™ ST were associated with mild inflammation and minimal-mild fibrosis/neovascularization, with no significant differences between groups. At both time points, Phasix™ was associated with minimal-mild inflammation/fibrosis and mild neovascularization. Strattice™ was associated with minimal inflammation/fibrosis, with minimal neovascularization at 12 weeks, which increased to mild by 24 weeks. Strattice™ exhibited significantly less neovascularization than Phasix™ at 12 weeks and significantly greater inflammation at 24 weeks due to remodeling. Phasix™ ST demonstrated mechanical and histological properties comparable to partially absorbable (Ventralight™ ST) and fully resorbable (Phasix™) meshes at 12 and 24 weeks in this model. Data also suggest that fully absorbable meshes with longer-term resorption profiles may provide improved mechanical and histological properties compared to biologically derived scaffolds.

  7. Complications of grafts used in female pelvic floor reconstruction: Mesh erosion and extrusion

    Directory of Open Access Journals (Sweden)

    Tanya M Nazemi


    Full Text Available Introduction: Various grafts have been used in the treatment of urinary incontinence and pelvic prolapse. Autologous materials such as muscle and fascia were first utilized to provide additional anatomic support to the periurethral and pelvic tissues; however, attempts to minimize the invasiveness of the procedures have led to the use of synthetic materials. Complications such as infection and erosion or extrusion associated with these materials may be troublesome to manage. We review the literature and describe a brief overview of grafts used in pelvic floor reconstruction and focus on the management complications specifically related to synthetic materials. Materials and Methods: We performed a comprehensive review of the literature on grafts used in pelvic floor surgery using MEDLINE and resources cited in those peer-reviewed manuscripts. The results are presented. Results: Biologic materials provide adequate cure rates but have associated downfalls including potential complications from harvesting, variable tissue quality and cost. The use of synthetic materials as an alternative graft in pelvic floor repairs has become a popular option. Of all synthetic materials, the type I macroporous polypropylene meshes have demonstrated superiority in terms of efficacy and fewer complication rates due to their structure and composition. Erosion and extrusion of mesh are common and troublesome complications that may be managed conservatively with observation with or without local hormone therapy, with transvaginal debridement or with surgical exploration and total mesh excision, dependent upon the location of the mesh and the mesh type utilized. Conclusions: The ideal graft would provide structural integrity and durability with minimal adverse reaction by the host tissue. Biologic materials in general tend to have fewer associated complications, however, the risks of harvesting, variable integrity of allografts, availability and high cost has led to the

  8. Clinical experience with titanium mesh in reconstruction of massive chest wall defects following oncological resection (United States)

    Yang, Haitang; Tantai, Jicheng


    Objectives To present our experience of reconstructing wide defects with porously titanium mesh after radical resection of malignant chest wall tumors. Methods A retrospective review of surgical reconstruction for large chest wall resections with titanium mesh was conducted from January 2009 to August 2014 in Shanghai Chest Hospital. Results A total of 27 patients underwent major chest wall reconstructions with titanium mesh, following oncological resections. Chest wall sarcomas were the most frequent (63.0%). The mean tumor size was 72.4 (range, 36-140) cm2. The average size of the applied porously titanium mesh was 140.9 (range, 80-225) cm2. Mean postoperative length of stay was 7.1 (range, 4-14) days. There were no perioperative mortalities. Four (14.8%) patients experienced treatable complications. All had a resection of at least 3 ribs (median 3, mean 3.5 ribs). A total of 22 patients underwent ribs without sternal resections, and five patients underwent partial sternal resections with adjacent costal cartilage. Anterior chest wall resections were performed in 13 patients while lateral chest wall resections were performed in 9 patients. Three patients had extended resections beyond the chest wall in patients with primary chest wall malignancies, including two with wedge resections of lung and one with partial resection of pericardium. No patient was lost to follow-up. Mean follow-up was 30.7 months. Neither chest wall instability nor wound infection/necrosis was observed. Of these, 23 patients (85.2%) were alive at the last follow-up. Local recurrence was detected in three cases. The 5-year disease-free and overall survivals of primary chest tumors were 72.1% and 80.8%, respectively. Conclusions Our results showed that chest wall reconstruction utilizing synthetic titanium meshes following extensive resections of the chest wall malignant tumors allowed adequate resection size, with acceptable complications and survival benefits. PMID:26380739

  9. Meshed split skin graft for extensive vitiligo

    Directory of Open Access Journals (Sweden)

    Srinivas C


    Full Text Available A 30 year old female presented with generalized stable vitiligo involving large areas of the body. Since large areas were to be treated it was decided to do meshed split skin graft. A phototoxic blister over recipient site was induced by applying 8 MOP solution followed by exposure to UVA. The split skin graft was harvested from donor area by Padgett dermatome which was meshed by an ampligreffe to increase the size of the graft by 4 times. Significant pigmentation of the depigmented skin was seen after 5 months. This procedure helps to cover large recipient areas, when pigmented donor skin is limited with minimal risk of scarring. Phototoxic blister enables easy separation of epidermis thus saving time required for dermabrasion from recipient site.

  10. Nondispersive optical activity of meshed helical metamaterials. (United States)

    Park, Hyun Sung; Kim, Teun-Teun; Kim, Hyeon-Don; Kim, Kyungjin; Min, Bumki


    Extreme optical properties can be realized by the strong resonant response of metamaterials consisting of subwavelength-scale metallic resonators. However, highly dispersive optical properties resulting from strong resonances have impeded the broadband operation required for frequency-independent optical components or devices. Here we demonstrate that strong, flat broadband optical activity with high transparency can be obtained with meshed helical metamaterials in which metallic helical structures are networked and arranged to have fourfold rotational symmetry around the propagation axis. This nondispersive optical activity originates from the Drude-like response as well as the fourfold rotational symmetry of the meshed helical metamaterials. The theoretical concept is validated in a microwave experiment in which flat broadband optical activity with a designed magnitude of 45° per layer of metamaterial is measured. The broadband capabilities of chiral metamaterials may provide opportunities in the design of various broadband optical systems and applications.

  11. Isomorphic routing on a toroidal mesh (United States)

    Mao, Weizhen; Nicol, David M.


    We study a routing problem that arises on SIMD parallel architectures whose communication network forms a toroidal mesh. We assume there exists a set of k message descriptors (xi, yi), where (xi, yi) indicates that the ith message's recipient is offset from its sender by xi hops in one mesh dimension, and yi hops in the other. Every processor has k messages to send, and all processors use the same set of message routing descriptors. The SIMD constraint implies that at any routing step, every processor is actively routing messages with the same descriptors as any other processor. We call this isomorphic routing. Our objective is to find the isomorphic routing schedule with least makespan. We consider a number of variations on the problem, yielding complexity results from O(k) to NP-complete. Most of our results follow after we transform the problem into a scheduling problem, where it is related to other well-known scheduling problems.

  12. Partitioning of unstructured meshes for load balancing

    International Nuclear Information System (INIS)

    Martin, O.C.; Otto, S.W.


    Many large-scale engineering and scientific calculations involve repeated updating of variables on an unstructured mesh. To do these types of computations on distributed memory parallel computers, it is necessary to partition the mesh among the processors so that the load balance is maximized and inter-processor communication time is minimized. This can be approximated by the problem, of partitioning a graph so as to obtain a minimum cut, a well-studied combinatorial optimization problem. Graph partitioning algorithms are discussed that give good but not necessarily optimum solutions. These algorithms include local search methods recursive spectral bisection, and more general purpose methods such as simulated annealing. It is shown that a general procedure enables to combine simulated annealing with Kernighan-Lin. The resulting algorithm is both very fast and extremely effective. (authors) 23 refs., 3 figs., 1 tab

  13. Adaptive upscaling with the dual mesh method

    Energy Technology Data Exchange (ETDEWEB)

    Guerillot, D.; Verdiere, S.


    The objective of this paper is to demonstrate that upscaling should be calculated during the flow simulation instead of trying to enhance the a priori upscaling methods. Hence, counter-examples are given to motivate our approach, the so-called Dual Mesh Method. The main steps of this numerical algorithm are recalled. Applications illustrate the necessity to consider different average relative permeability values depending on the direction in space. Moreover, these values could be different for the same average saturation. This proves that an a priori upscaling cannot be the answer even in homogeneous cases because of the {open_quotes}dynamical heterogeneity{close_quotes} created by the saturation profile. Other examples show the efficiency of the Dual Mesh Method applied to heterogeneous medium and to an actual field case in South America.

  14. Variational mesh segmentation via quadric surface fitting

    KAUST Repository

    Yan, Dongming


    We present a new variational method for mesh segmentation by fitting quadric surfaces. Each component of the resulting segmentation is represented by a general quadric surface (including plane as a special case). A novel energy function is defined to evaluate the quality of the segmentation, which combines both L2 and L2 ,1 metrics from a triangle to a quadric surface. The Lloyd iteration is used to minimize the energy function, which repeatedly interleaves between mesh partition and quadric surface fitting. We also integrate feature-based and simplification-based techniques in the segmentation framework, which greatly improve the performance. The advantages of our algorithm are demonstrated by comparing with the state-of-the-art methods. © 2012 Elsevier Ltd. All rights reserved.

  15. Surgical endodontics. (United States)

    Carrotte, P


    Root canal treatment usually fails because infection remains within the root canal. An orthograde attempt at re-treatment should always be considered first. However, when surgery is indicated, modern microtechniques coupled with surgical magnification will lead to a better prognosis. Careful management of the hard and soft tissues is essential, specially designed ultrasonic tips should be used for root end preparation which should ideally be sealed with MTA. All cases should be followed up until healing is seen, or failure accepted, and should form a part of clinical audit.

  16. Diffusive mesh relaxation in ALE finite element numerical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Dube, E.I.


    The theory for a diffusive mesh relaxation algorithm is developed for use in three-dimensional Arbitary Lagrange/Eulerian (ALE) finite element simulation techniques. This mesh relaxer is derived by a variational principle for an unstructured 3D grid using finite elements, and incorporates hourglass controls in the numerical implementation. The diffusive coefficients are based on the geometric properties of the existing mesh, and are chosen so as to allow for a smooth grid that retains the general shape of the original mesh. The diffusive mesh relaxation algorithm is then applied to an ALE code system, and results from several test cases are discussed.

  17. TPM: Tree-Particle-Mesh code (United States)

    Bode, Paul


    TPM carries out collisionless (dark matter) cosmological N-body simulations, evolving a system of N particles as they move under their mutual gravitational interaction. It combines aspects of both Tree and Particle-Mesh algorithms. After the global PM forces are calculated, spatially distinct regions above a given density contrast are located; the tree code calculates the gravitational interactions inside these denser objects at higher spatial and temporal resolution. The code is parallel and uses MPI for message passing.

  18. Wireless experiments on a Motorola mesh testbed.

    Energy Technology Data Exchange (ETDEWEB)

    Riblett, Loren E., Jr.; Wiseman, James M.; Witzke, Edward L.


    Motomesh is a Motorola product that performs mesh networking at both the client and access point levels and allows broadband mobile data connections with or between clients moving at vehicular speeds. Sandia National aboratories has extensive experience with this product and its predecessors in infrastructure-less mobile environments. This report documents experiments, which characterize certain aspects of how the Motomesh network performs when obile units are added to a fixed network infrastructure.

  19. Symmetries and the coarse-mesh method

    International Nuclear Information System (INIS)

    Makai, M.


    This report approaches the basic problem of the coarse-mesh method from a new side. Group theory is used for the determination of the space dependency of the flux. The result is a method called ANANAS after the analytic-analytic solution. This method was tested on two benchmark problems: one given by Melice and the IAEA benchmark. The ANANAS program is an experimental one. The method was intended for use in hexagonal geometry. (Auth.)



    Shaleen; Mahendra; Shahapurkar; Md. Javed; Ankur; Shiv; Eshan


    : Post-operative wound infection is defined as surgical site infection from 0-30 days after surgery, or infection to surgical site till one year in cases of implants like mesh, vascular grafts and prosthesis. This study was done to find out incidence of post-operative wound infection in surgical patients in rural setup. This study of post-operative wound infection was carried out from August 2008 to August 2010. The study is of 3275 patients who underwent surgery in the A.V.B....

  1. Numerical Investigation of Corrugated Wire Mesh Laminate

    Directory of Open Access Journals (Sweden)

    Jeongho Choi


    Full Text Available The aim of this work is to develop a numerical model of Corrugated Wire Mesh Laminate (CWML capturing all its complexities such as nonlinear material properties, nonlinear geometry and large deformation behaviour, and frictional behaviour. Development of such a model will facilitate numerical simulation of the mechanical behaviour of the wire mesh structure under various types of loading as well as the variation of the CWML configuration parameters to tailor its mechanical properties to suit the intended application. Starting with a single strand truss model consisting of four waves with a bilinear stress-strain model to represent the plastic behaviour of stainless steel, the finite element model is gradually built up to study single-layer structures with 18 strands of corrugated wire meshes consistency and double- and quadruple-layered laminates with alternating crossply orientations. The compressive behaviour of the CWML model is simulated using contact elements to model friction and is compared to the load-deflection behaviour determined experimentally in uniaxial compression tests. The numerical model of the CWML is then employed to conduct the aim of establishing the upper and lower bounds of stiffness and load capacity achievable by such structures.

  2. MeSH Now: automatic MeSH indexing at PubMed scale via learning to rank. (United States)

    Mao, Yuqing; Lu, Zhiyong


    MeSH indexing is the task of assigning relevant MeSH terms based on a manual reading of scholarly publications by human indexers. The task is highly important for improving literature retrieval and many other scientific investigations in biomedical research. Unfortunately, given its manual nature, the process of MeSH indexing is both time-consuming (new articles are not immediately indexed until 2 or 3 months later) and costly (approximately ten dollars per article). In response, automatic indexing by computers has been previously proposed and attempted but remains challenging. In order to advance the state of the art in automatic MeSH indexing, a community-wide shared task called BioASQ was recently organized. We propose MeSH Now, an integrated approach that first uses multiple strategies to generate a combined list of candidate MeSH terms for a target article. Through a novel learning-to-rank framework, MeSH Now then ranks the list of candidate terms based on their relevance to the target article. Finally, MeSH Now selects the highest-ranked MeSH terms via a post-processing module. We assessed MeSH Now on two separate benchmarking datasets using traditional precision, recall and F 1 -score metrics. In both evaluations, MeSH Now consistently achieved over 0.60 in F-score, ranging from 0.610 to 0.612. Furthermore, additional experiments show that MeSH Now can be optimized by parallel computing in order to process MEDLINE documents on a large scale. We conclude that MeSH Now is a robust approach with state-of-the-art performance for automatic MeSH indexing and that MeSH Now is capable of processing PubMed scale documents within a reasonable time frame. .

  3. Prosthetic mesh repair of abdominal wall hernias in horses. (United States)

    Tóth, Ferenc; Schumacher, Jim


    Repair of hernias of the abdominal wall of horses is often augmented by inserting a prosthetic mesh. In this review, we describe the various characteristics of prosthetic meshes used for hernia repair and present 2 systems that are used by surgeons in the human medical field to classify techniques of prosthetic mesh herniorrhaphy. Both of these classification systems distinguish between onlay, inlay, sublay, and underlay placements of mesh, based on the location within the abdominal wall in which the prosthetic mesh is inserted. We separate the published techniques of prosthetic mesh herniorrhaphy of horses using this classification system, ascribing names to the techniques of herniorrhaphy where none existed, and report the success rates and complications associated with each technique. By introducing a classification system widely used in the human medical field and illustrating each technique in a figure, we hope to clarify inconsistent nomenclature associated with prosthetic mesh herniorrhaphy performed by veterinary surgeons. © 2018 The American College of Veterinary Surgeons.

  4. Data-Parallel Mesh Connected Components Labeling and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Cyrus; Childs, Hank; Gaither, Kelly


    We present a data-parallel algorithm for identifying and labeling the connected sub-meshes within a domain-decomposed 3D mesh. The identification task is challenging in a distributed-memory parallel setting because connectivity is transitive and the cells composing each sub-mesh may span many or all processors. Our algorithm employs a multi-stage application of the Union-find algorithm and a spatial partitioning scheme to efficiently merge information across processors and produce a global labeling of connected sub-meshes. Marking each vertex with its corresponding sub-mesh label allows us to isolate mesh features based on topology, enabling new analysis capabilities. We briefly discuss two specific applications of the algorithm and present results from a weak scaling study. We demonstrate the algorithm at concurrency levels up to 2197 cores and analyze meshes containing up to 68 billion cells.

  5. Fixation of Light Weight Polypropylene Mesh with n-Butyl-2-cyanocrylate in Pelvic Floor Surgery: Experimental Design Approach in Sheep for Effectiveness Evaluation

    Directory of Open Access Journals (Sweden)

    Sandra Barbosa


    Full Text Available Objective. The aim of this study was to find a proper experimental design and to evaluate n-butyl-2-cyanoacrylate (Histoacryl as a fixation method for a light-weight and large pore PP mesh (Synthetic PP Mesh-1 using the sheep as an animal model. Methods. Posterior vaginal implantation by means of episiotomy was used to implant 8 ewes which were evaluated macroscopically and histologically at 3 months (n=4 and 6 months (n=4 post-surgery. In previous pilot studies anterior vaginal implantation was evaluated, as well as different synthetic mesh materials, sizes and fixation methods (n=1 to 3 during three weeks. In all cases a clinical evaluation of the animal was performed. Results. A reduction in the mesh size (Synthetic PP Mesh-1 together with precise application of the surgical glue Histoacryl to fix the mesh yielded significantly better histocompatibility results (P<0.01 compared to larger size or other fixation methods. Conclusion. The combination of Synthetic PP Mesh-1 with Histoacryl offered a high degree of graft integration without vaginal ulceration and a minimal foreign body reaction, being the sheep a proper animal model to test these types of medical devices.

  6. Comparison of Recurrence Rates in Obese and Non-Obese Patients Undergoing Ventral Hernia Repair with Lighter-Weight, Partially Absorbable Mesh. (United States)

    Tollens, Tim; Speybrouck, Sabrina; Devroe, Kurt; Terry, Catherine; Alevoet, Chris; Divilio, L Thomas; Patel, Bababhai; Vanrykel, Jean-Pierre Vanrykel


    Lighter-weight, large pore meshes with absorbable layers are designed for intra-abdominal placement in laparoscopic ventral hernia repair. This retrospective review of 86 patients who underwent ventral hernia repair with PROCEED™ Surgical Mesh (Ethicon, Inc., Somerville, NJ) represents an evaluation of a cohort of patients implanted with this mesh. All patients implanted with PROCEED Mesh for ventral hernia repair between October 2006 and December 2007 were contacted and asked to participate in an evaluation of their hernia repair. Patients were evaluated for pain, recurrence of their hernia and other potential complications. Eight patients underwent open repair; all others were performed laparoscopically. One patient continued to have pain at 1 year. Twelve developed seromas early on and 5 required drainage by a single puncture each. None persisted. There were 4 recurrences with none in patients with a Body Mass Index 3 32. One case of abdominal wall cellulitis responded to antibiotics. There were no wound infections, mesh infections, bowel obstructions or enteric fistulas. This study demonstrates the utility of a lighter-weight, large pore, partially absorbable mesh for intraperitoneal use in laparoscopic ventral hernia repair and indicates this mesh is strong enough for use in obese patients.

  7. Reconstruction of chest wall using a two-layer prolene mesh and bone cement sandwich. (United States)

    Aghajanzadeh, Manouchehr; Alavi, Ali; Aghajanzadeh, Gilda; Ebrahimi, Hannan; Jahromi, Sina Khajeh; Massahnia, Sara


    Wide surgical resection is the most effective treatment for the vast majority of chest wall tumors. This study evaluated the clinical success of chest wall reconstruction using a Prolene mesh and bone cement prosthetic sandwich. The records of all patients undergoing chest wall resection and reconstruction were reviewed. Surgical indications, the location and size of the chest wall defect, diaphragm resection, pulmonary performance, postoperative complications, and survival of each patient were recorded. From 1998 to 2008, 43 patients (27 male, 16 female; mean age of 48 years) underwent surgery in our department to treat malignant chest wall tumors: chondrosarcoma (23), osteosarcoma (8), spindle cell sarcoma (6), Ewing's sarcoma (2), and others (4). Nine sternectomies and 34 antero-lateral and postero-lateral chest wall resections were performed. Postoperatively, nine patients experienced respiratory complications, and one patient died because of respiratory failure. The overall 4-year survival rate was 60 %. Chest wall reconstruction using a Prolene mesh and bone cement prosthetic sandwich is a safe and effective surgical procedure for major chest wall defects.

  8. Our Experience with the Use of Low Cost Mesh in Tension-Free Inguinal Hernioplasty in Northern Ghana. (United States)

    Yenli, Edwin M T; Abanga, John; Tabiri, Stephen; Kpangkpari, Steve; Tigwii, Aubrey; Nsor, Azare; Amesiya, Robert; Ekremet, Kwame; Abantanga, Francis A


    To describe our experience and success in the use of low cost mesh for the repair of inguinal hernias in consenting adult patients. A prospective study was carried out from August 2010 to December 2013 in ten district hospitals across Northern Ghana. The patients were divided into four groups according to Kingsnorth's classification of hernias. Low cost mesh was used to repair uncomplicated groin hernia. Those hernias associated with complications were excluded. We assessed the patients for wound infection, long term incisional pain and recurrence of hernia. The data collected was entered, cleaned, validated and analyzed. One hundred and eighty-four patients had tension-free repair of their inguinal hernias using non-insecticide impregnated mosquito net mesh. The median age of the patients was 51 years. The male to female ratio was 7:1. Using Kingsnorth's classification, H3 hernias were (62, 33.7%), followed by the H1 group (56, 30.4%). Local anaesthesia was used in 70% and less than 5% had general anaesthesia. The cost of low cost mesh to each patient was calculated to be $ 1.8(GH¢7.2) vs $ 45(GH¢ 180) for commercial mesh of same size. The benefit to the patient and the facility was enormous. Wound hematoma was noticed in 7% while superficial surgical site infection was 3%. No patient reported of long term wound pain. There was no recurrence of hernia. Low cost mesh such as sterilized mosquito net mesh for use in hernioplasty in resource-limited settings is reasonable, acceptable and cost-effective, it should be widely propagated. None declared.

  9. Extracellular matrix regenerative graft attenuates the negative impact of polypropylene prolapse mesh on vagina in rhesus macaque. (United States)

    Liang, Rui; Knight, Katrina; Barone, William; Powers, Robert W; Nolfi, Alexis; Palcsey, Stacy; Abramowitch, Steven; Moalli, Pamela A


    The use of wide pore lightweight polypropylene mesh to improve anatomical outcomes in the surgical repair of prolapse has been hampered by mesh complications. One of the prototype prolapse meshes has been found to negatively impact the vagina by inducing a decrease in smooth muscle volume and contractility and the degradation of key structural proteins (collagen and elastin), resulting in vaginal degeneration. Recently, bioscaffolds derived from extracellular matrix have been used to mediate tissue regeneration and have been widely adopted in tissue engineering applications. Here we aimed to: (1) define whether augmentation of a polypropylene prolapse mesh with an extracellular matrix regenerative graft in a primate sacrocolpopexy model could mitigate the degenerative changes; and (2) determine the impact of the extracellular matrix graft on vagina when implanted alone. A polypropylene-extracellular matrix composite graft (n = 9) and a 6-layered extracellular matrix graft alone (n = 8) were implanted in 17 middle-aged parous rhesus macaques via sacrocolpopexy and compared to historical data obtained from sham (n = 12) and the polypropylene mesh (n = 12) implanted by the same method. Vaginal function was measured in passive (ball-burst test) and active (smooth muscle contractility) mechanical tests. Vaginal histomorphologic/biochemical assessments included hematoxylin-eosin and trichrome staining, immunofluorescent labeling of α-smooth muscle actin and apoptotic cells, measurement of total collagen, collagen subtypes (ratio III/I), mature elastin, and sulfated glycosaminoglycans. Statistical analyses included 1-way analysis of variance, Kruskal-Wallis, and appropriate post-hoc tests. The host inflammatory response in the composite mesh-implanted vagina was reduced compared to that following implantation with the polypropylene mesh alone. The increase in apoptotic cells observed with the polypropylene mesh was blunted in the composite (overall P matrix graft

  10. Standard of Open Surgical Repair of Suprapubic Incisional Hernias. (United States)

    Renard, Yohann; Simonneau, Anne-Charlotte; de Mestier, Louis; Teuma, Lugdivine; Meffert, Jean-Luc; Palot, Jean-Pierre; Kianmanesh, Reza


    Suprapubic incisional hernias (SIH) are a rare wall defect, whose surgical management is challenging because of limited literature. The proximity of the hernia to bone, vascular, nerve, and urinary structures, and the absence of posterior rectus sheath in this location imply adequate technique of surgical repair. We aimed to describe a cohort of female patients operated on for SIH after gynecological surgery using a homogeneous surgical technique and to report surgical outcomes. The records of all consecutive patients operated on for SIH in a specialized surgical center between January 2009 and January 2015 were retrospectively reviewed. The same open technique was performed, i.e., using a mesh placed inferiorly in the preperitoneal space of Retzius, with large overlap, and fixed on the Cooper's ligaments, through the muscles superiorly and laterally with strong tension, in a sublay or underlay position. The cohort included 71 female patients. SIH were recurrent in 31% of patients and was related to cesarean in 32 patients (45.1%) and to gynecologic surgery in 39 patients (54.9%). The mesh was totally extraperitoneal in 76.1% of patients. The postoperative mortality rate was null. The rate of specific surgical complications was 29.6%. After a median follow-up of 30.3 months, the recurrence rate was 7%. The open approach for SIH repair was safe and efficient. Due to the paucity of adequate scientific studies, this reproducible open method could help moving toward a standardization of SIH surgical management.

  11. Diffusion of compact macromolecules through polymer meshes: mesh dynamics and probe dynamics

    International Nuclear Information System (INIS)

    Biehl, R.; Guo, X.; Prud'homme, R.K.; Monkenbusch, M.; Allgeier, J.; Richter, D.


    The diffusion of compact macromolecules in polymer networks is examined to understand how polymer networks or gels could be used to filter different types of macromolecules. We present new measurements of the network and probe dynamics by neutron spin-echo spectroscopy (NSE). The investigated system consists of the protein α-lactalbumin (R g =15.2 Angst) as probe and a network of high molecular weight polyethylenoxide. The high molecular weight ensures a long disentanglement time for the polymer in order to create a stable network. We compare the network dynamics and the dynamics of the probe protein in the network at different mesh sizes. We study the dynamics at different q values between 0.03 and 0.22 Angst -1 . The corresponding length scales reach from distances smaller than the mesh size to larger than the mesh size


    Directory of Open Access Journals (Sweden)

    Danny Kurniawan Darianto


    Full Text Available A patient undergoing surgery faces great physiologic and psychologic stress. so nutritional demands are greatly increased during this period and deficiencies can easily develop. If these deficiencies are allowed to develop and are not in screening, serious malnutrition and clinical problem can occur. Therefore careful attention must be given to a patient's nutritional status in preparation of surgery, as well as to the individual nutritional needs. If these needs are met, complications are less likely developing. Natural resources provide for rapid recovery. Proper nutrition can speed healing in surgical patients with major trauma, severe malnutition, burns, and other severe illnesses. New techniques for tube feeding, intravenous nutrition for patients with serious weight loss due to gastrointestinal disorders, and use of supplements can hasten wound healing and shorten recovery times.

  13. A laparoscopic high anterior resection for sigmoid cancer with extraction through incarcerated left inguinal hernia repaired with Permacol mesh. (United States)

    Carr, William Reginald Joseph; O'Dair, Graham


    A 65-year-old man presented to the general surgical outpatients with an incarcerated left inguinal hernia. Initial investigations revealed an iron deficiency anaemia that was investigated with a colonoscopy and gastroscopy. This revealed a sigmoid cancer and the staging CT scan confirmed a tumour incarcerated in the sac of the left inguinal hernia. We proceeded with a laparoscopic high anterior resection using the inguinal hernia as the extraction site. The hernia was repaired using Permacol mesh. No postoperative complications occurred.

  14. Promising results after vacuum-assisted wound closure and mesh-mediated fascial traction

    DEFF Research Database (Denmark)

    Kleif, Jakob; Fabricius, Rasmus; Bertelsen, Claus Anders


    Patients with an open abdomen (OA) present a major challenge to the surgeon. High mortality and associated complication rates have been reported depending on the specific method of temporary abdominal closure, the primary disorder and any co-morbidity. Vacuum-assisted wound closure and mesh......-mediated fascial traction (VAWCM) is a novel technique recently introduced for late fascial closure of the OA. In previous studies, the disease aetiologies were mainly vascular and visceral surgical disease and trauma. We report our results using VAWCM in a non-trauma patient population treated with an OA due...


    Directory of Open Access Journals (Sweden)

    Pei Ping


    Full Text Available Wireless Mesh network (WMN are increasingly becoming popular as low cost alternatives to wired network for providing broadband access to users. A wireless mesh network (WMN is a communication networks made up of radio nodes organized in a mesh topology. It is also a form of wireless network. Wireless mesh networks often consist of mesh clients, mesh routers and gateways. The mesh clients are often laptops, cell phones and other wireless devices while the mesh routers forward traffic to and from the gateways, which may, but need not, be connected, to the Internet. In this paper, we discuss different radio frequency range in wireless connected to Access Point (AP and the project from Belarus – China great stone industry park in Mesh network. The China-Belarus industrial park is a territorial entity with the area of approximately 80 sq. km with a special legal status for the provision of comfortable conditions for business conducting. The Park is located in a unique natural complex 25 km far from Minsk, the capital of the Republic of Belarus. It is in close proximity to the international airport, railway lines, a transnational highway Berlin-Moscow. The result of analysis shows distribution of AP and covering services in great stone industry park. Mesh network provides robustness and load balancing in wireless networks communication.

  16. Performance of FACTS equipment in Meshed systems

    Energy Technology Data Exchange (ETDEWEB)

    Lerch, E.; Povh, D. [Siemens AG, Berlin (Germany)


    Modern power electronic devices such as thyristors and GTOs have made it possible to design controllable network elements, which will play a considerable role in ensuring reliable economic operation of transmission systems as a result of their capability to rapidly change active and reactive power. A number of FACTS elements for high-speed active and reactive power control will be described. Control of power system fluctuations in meshed systems by modulation of active and reactive power will be demonstrated using a number of examples. (author) 7 refs., 11 figs.

  17. MEDIT : An interactive Mesh visualization Software


    Frey, Pascal


    This technical report describes the main features of MEDIT (This software wa registered with the APP under n° IDDN.FR.001.410023.00.R.P. 2001.000.10800 on january 25, 2001.), an interactive mesh visualization tool developped in the Gamma project at INRIA-Rocquencourt. Based on the graphic standard OpenGL, this software has been specifically designed to fulfill most of the common requirements of engineers and numericians, in the context of numerical simulations. This program is rather intuitiv...

  18. Performance Evaluation of Coded Meshed Networks

    DEFF Research Database (Denmark)

    Krigslund, Jeppe; Hansen, Jonas; Pedersen, Morten Videbæk


    of the former to enhance the gains of the latter. We first motivate our work through measurements in WiFi mesh networks. Later, we compare state-of-the-art approaches, e.g., COPE, RLNC, to CORE. Our measurements show the higher reliability and throughput of CORE over other schemes, especially, for asymmetric......We characterize the performance of intra- and inter-session network coding (NC) in wireless networks using real-life implementations. We compare this performance to a recently developed hybrid approach, called CORE, which combines intra- and inter-session NC exploiting the code structure...

  19. Unbiased Sampling and Meshing of Isosurfaces

    KAUST Repository

    Yan, Dongming


    In this paper, we present a new technique to generate unbiased samples on isosurfaces. An isosurface, F(x,y,z) = c , of a function, F , is implicitly defined by trilinear interpolation of background grid points. The key idea of our approach is that of treating the isosurface within a grid cell as a graph (height) function in one of the three coordinate axis directions, restricted to where the slope is not too high, and integrating / sampling from each of these three. We use this unbiased sampling algorithm for applications in Monte Carlo integration, Poisson-disk sampling, and isosurface meshing.

  20. Generating quality tetrahedral meshes from binary volumes

    DEFF Research Database (Denmark)

    Hansen, Mads Fogtmann; Bærentzen, Jakob Andreas; Larsen, Rasmus


    use these measures to generate high quality meshes from signed distance maps. This paper also describes an approach for computing (smooth) signed distance maps from binary volumes as volumetric data in many cases originate from segmentation of objects from imaging techniques such as CT, MRI, etc...... generation algorithm on four examples (torus, Stanford dragon, brain mask, and pig back) and report the dihedral angle, aspect ratio and radius-edge ratio. Even though, the algorithm incorporates none of the mentioned quality measures in the compression stage it receives a good score for all these measures...

  1. Image-Based Geometric Modeling and Mesh Generation

    CERN Document Server


    As a new interdisciplinary research area, “image-based geometric modeling and mesh generation” integrates image processing, geometric modeling and mesh generation with finite element method (FEM) to solve problems in computational biomedicine, materials sciences and engineering. It is well known that FEM is currently well-developed and efficient, but mesh generation for complex geometries (e.g., the human body) still takes about 80% of the total analysis time and is the major obstacle to reduce the total computation time. It is mainly because none of the traditional approaches is sufficient to effectively construct finite element meshes for arbitrarily complicated domains, and generally a great deal of manual interaction is involved in mesh generation. This contributed volume, the first for such an interdisciplinary topic, collects the latest research by experts in this area. These papers cover a broad range of topics, including medical imaging, image alignment and segmentation, image-to-mesh conversion,...

  2. Fire performance of basalt FRP mesh reinforced HPC thin plates

    DEFF Research Database (Denmark)

    Hulin, Thomas; Hodicky, Kamil; Schmidt, Jacob Wittrup


    An experimental program was carried out to investigate the influence of basalt FRP (BFRP) reinforcing mesh on the fire behaviour of thin high performance concrete (HPC) plates applied to sandwich elements. Samples with BFRP mesh were compared to samples with no mesh, samples with steel mesh...... and samples displaying a full sandwich structure. Final results confirmed the bond loss between concrete and BFRP mesh with temperature. The available void where the epoxy burnt away allowed the concrete matrix to release pressure and limit pore stresses, delaying spalling. It also reduced the mechanical...... on a linear increase of the volume of melted epoxy and the outflow of moisture from the concrete matrix. It was concluded that the use of a BFRP mesh to reinforce HPC exposed to fire reduces the mechanical strength despite a beneficial effect related to spalling....

  3. Improved mesh generator for the POISSON Group Codes

    International Nuclear Information System (INIS)

    Gupta, R.C.


    This paper describes the improved mesh generator of the POISSON Group Codes. These improvements enable one to have full control over the way the mesh is generated and in particular the way the mesh density is distributed throughout this model. A higher mesh density in certain regions coupled with a successively lower mesh density in others keeps the accuracy of the field computation high and the requirements on the computer time and computer memory low. The mesh is generated with the help of codes AUTOMESH and LATTICE; both have gone through a major upgrade. Modifications have also been made in the POISSON part of these codes. We shall present an example of a superconducting dipole magnet to explain how to use this code. The results of field computations are found to be reliable within a few parts in a hundred thousand even in such complex geometries

  4. Chemotherapy does not adversely impact outcome following post-incisional hernia repair with biomaterial mesh. (United States)

    Saied, Abdul; David, Jenny; LaBarbera, Kim; Katz, Steven C; Somasundar, Ponnandai


    Patients receiving chemotherapy are at increased risk for developing recurrent or post-incisional hernias (PIH). Biological materials are an alternative to synthetic mesh in contaminated fields. The impact of chemotherapy on biomaterial tissue ingrowth and integration has not been well studied. From 2008 to 2011 patients who underwent PIH repair with biomaterial mesh (Biodesign®) were selected. Patients were divided into two groups: those receiving chemotherapy (CT) and those not receiving chemotherapy (NCT). Forty-five patients were identified, 28 (62%) in the NCT group and 17 (38%) in the CT group. Median follow up for NCT and CT groups were 27 and 17 months, respectively. A total of 9/45 (20%) surgical site infections (SSI) were diagnosed, with 6/28 (21%) in the NCT and 3/17 (18%) in the CT group (P = 0.53). Seroma formation was seen in 5/28 (18%) of NCT patients and 4/17 (23%) in CT group (P = 0.46). Overall hernia recurrence rate was 22%, and the rates of recurrence were similar among the CT 3/17 (18%) and NCT 7/28 (25%) groups (P = 0.42). The use of perioperative chemotherapy did not increase the rate of wound complications following PIH repair with biologic mesh in this group of patients. © 2015 Wiley Periodicals, Inc.

  5. Dynamic Mesh Adaptation for Front Evolution Using Discontinuous Galerkin Based Weighted Condition Number Mesh Relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Greene, Patrick T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schofield, Samuel P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nourgaliev, Robert [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    A new mesh smoothing method designed to cluster mesh cells near a dynamically evolving interface is presented. The method is based on weighted condition number mesh relaxation with the weight function being computed from a level set representation of the interface. The weight function is expressed as a Taylor series based discontinuous Galerkin projection, which makes the computation of the derivatives of the weight function needed during the condition number optimization process a trivial matter. For cases when a level set is not available, a fast method for generating a low-order level set from discrete cell-centered elds, such as a volume fraction or index function, is provided. Results show that the low-order level set works equally well for the weight function as the actual level set. Meshes generated for a number of interface geometries are presented, including cases with multiple level sets. Dynamic cases for moving interfaces are presented to demonstrate the method's potential usefulness to arbitrary Lagrangian Eulerian (ALE) methods.

  6. Comparative study of ppen mesh repair and Desarda's no-mesh ...

    African Journals Online (AJOL)

    Background: The first author has described a new technique of pure tissue hernia repair and published his results previously1,2. This article describes the results of a comparative study of this new technique and the open mesh repair done in a district level general hospital set up in India. Methods: This is a retrospective ...

  7. Sorting on Reconfigurable Meshes: An Irregular Decomposition Approach


    Lai, Ten H.; Sheng, Ming-Jye


    Most algorithms for reconfigurable meshes (R-meshes) are based on the divide-and-conquer (DAC) strategy. Although the strategy per se does not require the subproblems to be equal in size, existing DAC algorithms for R-meshes do divide the problem approximately evenly. This paper demonstrates that dividing a problem evenly is not necessarily a good way to decompose a problem. There are occasions on which an irregular decomposition scheme may be preferable. We take this approach ...

  8. Adaptive-mesh zoning by the equipotential method

    Energy Technology Data Exchange (ETDEWEB)

    Winslow, A.M.


    An adaptive mesh method is proposed for the numerical solution of differential equations which causes the mesh lines to move closer together in regions where higher resolution in some physical quantity T is desired. A coefficient D > 0 is introduced into the equipotential zoning equations, where D depends on the gradient of T . The equations are inverted, leading to nonlinear elliptic equations for the mesh coordinates with source terms which depend on the gradient of D. A functional form of D is proposed.

  9. The Tera Multithreaded Architecture and Unstructured Meshes (United States)

    Bokhari, Shahid H.; Mavriplis, Dimitri J.


    The Tera Multithreaded Architecture (MTA) is a new parallel supercomputer currently being installed at San Diego Supercomputing Center (SDSC). This machine has an architecture quite different from contemporary parallel machines. The computational processor is a custom design and the machine uses hardware to support very fine grained multithreading. The main memory is shared, hardware randomized and flat. These features make the machine highly suited to the execution of unstructured mesh problems, which are difficult to parallelize on other architectures. We report the results of a study carried out during July-August 1998 to evaluate the execution of EUL3D, a code that solves the Euler equations on an unstructured mesh, on the 2 processor Tera MTA at SDSC. Our investigation shows that parallelization of an unstructured code is extremely easy on the Tera. We were able to get an existing parallel code (designed for a shared memory machine), running on the Tera by changing only the compiler directives. Furthermore, a serial version of this code was compiled to run in parallel on the Tera by judicious use of directives to invoke the "full/empty" tag bits of the machine to obtain synchronization. This version achieves 212 and 406 Mflop/s on one and two processors respectively, and requires no attention to partitioning or placement of data issues that would be of paramount importance in other parallel architectures.

  10. Basic Algorithms for the Asynchronous Reconfigurable Mesh

    Directory of Open Access Journals (Sweden)

    Yosi Ben-Asher


    Full Text Available Many constant time algorithms for various problems have been developed for the reconfigurable mesh (RM in the past decade. All these algorithms are designed to work with synchronous execution, with no regard for the fact that large size RMs will probably be asynchronous. A similar observation about the PRAM model motivated many researchers to develop algorithms and complexity measures for the asynchronous PRAM (APRAM. In this work, we show how to define the asynchronous reconfigurable mesh (ARM and how to measure the complexity of asynchronous algorithms executed on it. We show that connecting all processors in a row of an n×n ARM (the analog of barrier synchronization in the APRAM model can be solved with complexity Θ(nlog⁡n. Intuitively, this is average work time for solving such a problem. Next, we describe general a technique for simulating T -step synchronous RM algorithms on the ARM with complexity of Θ(T⋅n2log⁡n. Finally, we consider the simulation of the classical synchronous algorithm for counting the number of non-zero bits in an n bits vector using (k

  11. Intraperitoneal mesh devices for small midline hernias: mesh behavior in a porcine model. (United States)

    Reynvoet, E; Chiers, K; Van Overbeke, I; Troisi, R; Berrevoet, F


    Although clinical data on long-term efficacy are lacking, the use of self-expanding devices for intraperitoneal placement in the management of small midline hernias has been popularized. In the present experimental study, two different devices were investigated regarding tissue ingrowth, adhesion formation and solid mesh placement. Two devices of 4.3 cm diameter, one ePTFE-containing small pore polypropylene mesh (PP/ePTFE) and a multi-layered large-pore polypropylene patch with an oxidized cellulose anti-adhesive barrier (PP/ORC), both containing a self-deployment system, were placed intraperitoneally at the linea alba of 24 female pigs. A first laparoscopy was performed to evaluate mesh positioning against the abdominal wall. 1 (n = 6), 2 (n = 6), 4 (n = 6) and 12 weeks (n = 6) later, mesh appearance was inspected and adhesion formation was assessed. All meshes were excised for histological evaluation. Folding of the patch was more frequently observed at PP/ePTFE, yet no excessive cupping was noticed. Adhesions predominantly presented at short-term evaluation. Overall adhesion formation at all samples was significantly more extensive for PP/ORC (p = 0.048). Massive shrinkage was observed for PP/ORC: after a 12-week period 22% residual surface was preserved, compared to 83% for PP/ePTFE (p < 0.001). While at short-term inflammatory reaction was comparable, at long-term PP/ORC induced a significant more pronounced inflammatory and foreign body reaction. Although a strong deployment system provides adequate initial placement, shrinkage and excessive adhesion formation are much more prominent in the large-pore multi-layered restorbable devices compared to the ePTFE patch. This might influence long-term clinical outcome and caution seems warranted.

  12. Experimental Study Of Fog Water Harvesting By Stainless Steel Mesh


    Nikhil R. Pawar; Suman S. Jain; Smitha R. God


    The collection of fog water is a simple and sustainable technology to get hold of fresh water for various purposes. In areas where a substantial amount of fog can be obtained it is feasible to set up a stainless steel as well as black double layer plastic mesh structure for fog water harvesting. The mesh structure is directly exposed to the weather and the fog containing air is pushed through the active mesh surface by the wind. Afterward fog droplets are deposited on the active mesh area whi...

  13. Investigation of Mesh Choosing Parameters in Screen Printing System


    Ahmet AKGÜL


    The mesh, which is made by weaving of natural silk, plastic, or metal fibers, is basic material for screen-printing. Image is created on stretched on a frame in screen-printing. Mesh should be selected correctly for a high quality printing. Therefore, substrates, types of print job and mesh parameters have importance. Need to know more about to mesh, yarn type, yarn thickness, frequency of weaving, stretching tension, the kind of weaving, etc. In this study, for a high quality screen-printing...

  14. Reconfigurable lattice mesh designs for programmable photonic processors. (United States)

    Pérez, Daniel; Gasulla, Ivana; Capmany, José; Soref, Richard A


    We propose and analyse two novel mesh design geometries for the implementation of tunable optical cores in programmable photonic processors. These geometries are the hexagonal and the triangular lattice. They are compared here to a previously proposed square mesh topology in terms of a series of figures of merit that account for metrics that are relevant to on-chip integration of the mesh. We find that that the hexagonal mesh is the most suitable option of the three considered for the implementation of the reconfigurable optical core in the programmable processor.

  15. Dimensionality Reduction of Laplacian Embedding for 3D Mesh Reconstruction (United States)

    Mardhiyah, I.; Madenda, S.; Salim, R. A.; Wiryana, I. M.


    Laplacian eigenbases are the important thing that we have to process from 3D mesh information. The information of geometric 3D mesh are include vertices locations and the connectivity of graph. Due to spectral analysis, geometric 3D mesh for large and sparse graphs with thousands of vertices is not practical to compute all the eigenvalues and eigenvector. Because of that, in this paper we discuss how to build 3D mesh reconstruction by reducing dimensionality on null eigenvalue but retain the corresponding eigenvector of Laplacian Embedding to simplify mesh processing. The result of reducing information should have to retained the connectivity of graph. The advantages of dimensionality reduction is for computational eficiency and problem simplification. Laplacian eigenbases is the point of dimensionality reduction for 3D mesh reconstruction. In this paper, we show how to reconstruct geometric 3D mesh after approximation step of 3D mesh by dimensionality reduction. Dimensionality reduction shown by Laplacian Embedding matrix. Furthermore, the effectiveness of 3D mesh reconstruction method will evaluated by geometric error, differential error, and final error. Numerical approximation error of our result are small and low complexity of computational.

  16. Hexahedral finite element mesh coarsening using pillowing technique (United States)

    Staten, Matthew L [Pittsburgh, PA; Woodbury, Adam C [Provo, UT; Benzley, Steven E [Provo, UT; Shepherd, Jason F [Edgewood, NM


    A techniques for coarsening a hexahedral mesh is described. The technique includes identifying a coarsening region within a hexahedral mesh to be coarsened. A boundary sheet of hexahedral elements is inserted into the hexahedral mesh around the coarsening region. A column of hexahedral elements is identified within the boundary sheet. The column of hexahedral elements is collapsed to create an extraction sheet of hexahedral elements contained within the coarsening region. Then, the extraction sheet of hexahedral elements is extracted to coarsen the hexahedral mesh.

  17. An Algorithm for Parallel Sn Sweeps on Unstructured Meshes

    International Nuclear Information System (INIS)

    Pautz, Shawn D.


    A new algorithm for performing parallel S n sweeps on unstructured meshes is developed. The algorithm uses a low-complexity list ordering heuristic to determine a sweep ordering on any partitioned mesh. For typical problems and with 'normal' mesh partitionings, nearly linear speedups on up to 126 processors are observed. This is an important and desirable result, since although analyses of structured meshes indicate that parallel sweeps will not scale with normal partitioning approaches, no severe asymptotic degradation in the parallel efficiency is observed with modest (≤100) levels of parallelism. This result is a fundamental step in the development of efficient parallel S n methods

  18. Full-thickness skin graft vs. synthetic mesh in the repair of giant incisional hernia: a randomized controlled multicenter study. (United States)

    Clay, L; Stark, B; Gunnarsson, U; Strigård, K


    Repair of large incisional hernias includes the implantation of a synthetic mesh, but this may lead to pain, stiffness, infection and enterocutaneous fistulae. Autologous full-thickness skin graft as on-lay reinforcement has been tested in eight high-risk patients in a proof-of-concept study, with satisfactory results. In this multicenter randomized study, the use of skin graft was compared to synthetic mesh in giant ventral hernia repair. Non-smoking patients with a ventral hernia > 10 cm wide were randomized to repair using an on-lay autologous full-thickness skin graft or a synthetic mesh. The primary endpoint was surgical site complications during the first 3 months. A secondary endpoint was patient comfort. Fifty-three patients were included. Clinical evaluation was performed at a 3-month follow-up appointment. There were fewer patients in the skin graft group reporting discomfort: 3 (13%) vs. 12 (43%) (p = 0.016). Skin graft patients had less pain and a better general improvement. No difference was seen regarding seroma; 13 (54%) vs. 13 (46%), or subcutaneous wound infection; 5 (20%) vs. 7 (25%). One recurrence appeared in each group. Three patients in the skin graft group and two in the synthetic mesh group were admitted to the intensive care unit. No difference was seen for the primary endpoint short-term surgical complication. Full-thickness skin graft appears to be a reliable material for ventral hernia repair producing no more complications than when using synthetic mesh. Patients repaired with a skin graft have less subjective abdominal wall symptoms.

  19. MeshVoro: A Three-Dimensional Voronoi Mesh Building Tool for the TOUGH Family of Codes

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, C. M.; Boyle, K. L.; Reagan, M.; Johnson, J.; Rycroft, C.; Moridis, G. J.


    Few tools exist for creating and visualizing complex three-dimensional simulation meshes, and these have limitations that restrict their application to particular geometries and circumstances. Mesh generation needs to trend toward ever more general applications. To that end, we have developed MeshVoro, a tool that is based on the Voro (Rycroft 2009) library and is capable of generating complex threedimensional Voronoi tessellation-based (unstructured) meshes for the solution of problems of flow and transport in subsurface geologic media that are addressed by the TOUGH (Pruess et al. 1999) family of codes. MeshVoro, which includes built-in data visualization routines, is a particularly useful tool because it extends the applicability of the TOUGH family of codes by enabling the scientifically robust and relatively easy discretization of systems with challenging 3D geometries. We describe several applications of MeshVoro. We illustrate the ability of the tool to straightforwardly transform a complex geological grid into a simulation mesh that conforms to the specifications of the TOUGH family of codes. We demonstrate how MeshVoro can describe complex system geometries with a relatively small number of grid blocks, and we construct meshes for geometries that would have been practically intractable with a standard Cartesian grid approach. We also discuss the limitations and appropriate applications of this new technology.

  20. [The long-term results of the application of the polypropylene mesh for the plastic correction of extensive laryngo-tracheostomas]. (United States)

    Yagudin, R K; Yagudin, K F


    The objective of the present study was to estimate the long-term results of the closure of large laryngeal and tracheal stomas with the use of the polypropylene mesh. The study included 33 adult patients presenting with extensive laryngeal and tracheal stomas. A total of 34 surgical interventions were performed for alloplastic correction of these defects. The complete closure of the tracheal and laryngeal defects with the incorporation of the prosthesis and restoration of respiration was achieved in 88.2% of the alloplastic procedures. The long-term follow-up of the treated patients (median: 75 months) failed to reveal any signs of mesh rejection. Moreover, none of the patients reported an appreciable feeling of discomfort at the site of mesh localization. Thus, the results of the study indicate that the alloplastic correction of laryngeal and tracheal stomas with the implantation of the modern mesh prostheses from polypropylene monofilaments provides the safe and reliable alternative to autoplastic surgery. Low rigidity of the modern prosthetic meshes ensures good immediate results of implant survival in the absence of long-term complications associated with the durable presence of the polypropylene mesh on the neck.

  1. Does mesh offer an advantage over tissue in the open repair of umbilical hernias? A systematic review and meta-analysis. (United States)

    Aslani, N; Brown, C J


    To determine the best surgical approach for the open repair of primary umbilical hernias. Studies were identified through searching MEDLINE, EMBASE, and the Cochrane database, as well as hand-searching references. Randomized controlled trials (RCTs) and observational studies comparing mesh to suture repair for primary umbilical hernias published between January 1965 and October 2009 were included. Data regarding the recurrence rate, complications, number of subjects, length of follow-up, size of hernia, and type of mesh were extracted. Log odds ratios were calculated and weighed by the Mantel-Haenszel method to obtain a pooled estimate with 95% confidence interval (CI). A fixed effects model was used. Three RCTs and ten observational studies were identified. The pooled odds ratio (OR) for RCTs was 0.09 in favor of mesh (95% CI 0.02-0.39). The pooled OR for observational studies was 0.40 in favor of mesh (95% CI 0.21-0.75). There was no difference in complication rates between mesh and tissue repair in RCTs or observational studies. The use of mesh in umbilical hernia repair results in decreased recurrence and similar wound complications rates compared to tissue repair for primary umbilical hernias.

  2. TiLoop® Bra mesh used for immediate breast reconstruction: comparison of retropectoral and subcutaneous implant placement in a prospective single-institution series. (United States)

    Casella, Donato; Bernini, Marco; Bencini, Lapo; Roselli, Jenny; Lacaria, Maria Teresa; Martellucci, Jacopo; Banfi, Roberto; Calabrese, Claudio; Orzalesi, Lorenzo


    Immediate implant reconstruction after a conservative mastectomy is an attractive option made easier by prosthetic devices. Titanized polypropylene meshes are used as a hammock to cover the lower lateral implant pole. We conducted a prospective nonrandomized single-institution study of reconstructions using titanium-coated meshes either in a standard muscular mesh pocket or in a complete subcutaneous approach. The complete subcutaneous approach means to wrap an implant with titanized mesh in order to position the implant subcutaneously and spare muscles. Between November 2011 and January 2014, we performed immediate implant breast reconstructions after conservative mastectomies using TiLoop® Bra, either with the standard retropectoral or with a prepectoral approach. Selection criteria included only women with normal Body Mass Index (BMI), no large and very ptotic breasts, no history of smoking, no diabetes, and no previous radiotherapy. We analyzed short-term outcomes of such procedures and compared the outcomes to evaluate implant losses and surgical complications. A total of 73 mastectomies were performed. Group 1 comprised 29 women, 5 bilateral procedures, 34 reconstructions, using the standard muscular mesh pocket. Group 2 comprised 34 women, 5 bilateral procedures, 39 reconstructions with the prepectoral subcutaneous technique. Baseline and oncologic characteristics were homogeneous between the two groups. After a median follow-up period of 13 and 12 months, respectively, no implant losses were recorded in group 1, and one implant loss was recorded in group 2. We registered three surgical complications in group 1 and two surgical complications in group 2. Titanium-coated polypropylene meshes, as a tool for immediate definitive implant breast reconstruction, resulted as safe and effective in a short-term analysis, both for a retropectoral and a totally subcutaneous implant placement. Long-term results are forthcoming. A strict selection is mandatory to

  3. Visualization Tools for Adaptive Mesh Refinement Data

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Gunther H.; Beckner, Vincent E.; Childs, Hank; Ligocki,Terry J.; Miller, Mark C.; Van Straalen, Brian; Bethel, E. Wes


    Adaptive Mesh Refinement (AMR) is a highly effective method for simulations that span a large range of spatiotemporal scales, such as astrophysical simulations that must accommodate ranges from interstellar to sub-planetary. Most mainstream visualization tools still lack support for AMR as a first class data type and AMR code teams use custom built applications for AMR visualization. The Department of Energy's (DOE's) Science Discovery through Advanced Computing (SciDAC) Visualization and Analytics Center for Enabling Technologies (VACET) is currently working on extending VisIt, which is an open source visualization tool that accommodates AMR as a first-class data type. These efforts will bridge the gap between general-purpose visualization applications and highly specialized AMR visual analysis applications. Here, we give an overview of the state of the art in AMR visualization research and tools and describe how VisIt currently handles AMR data.

  4. Solid Mesh Registration for Radiotherapy Treatment Planning

    DEFF Research Database (Denmark)

    Noe, Karsten Østergaard; Sørensen, Thomas Sangild


    We present an algorithm for solid organ registration of pre-segmented data represented as tetrahedral meshes. Registration of the organ surface is driven by force terms based on a distance field representation of the source and reference shapes. Registration of internal morphology is achieved using...... on phantom data and prostate data obtained in vivo based on fiducial marker accuracy and inverse consistency of transformations. The parallel nature of the method allows an efficient implementation on a GPU and as a result the method is very fast. All validation registrations take less than 30 seconds...... to complete. The proposed method has many potential uses in image guided radiotherapy (IGRT) which relies on registration to account for organ deformation between treatment sessions....

  5. Parallel-In-Time For Moving Meshes

    Energy Technology Data Exchange (ETDEWEB)

    Falgout, R. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Manteuffel, T. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Southworth, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schroder, J. B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    With steadily growing computational resources available, scientists must develop e ective ways to utilize the increased resources. High performance, highly parallel software has be- come a standard. However until recent years parallelism has focused primarily on the spatial domain. When solving a space-time partial di erential equation (PDE), this leads to a sequential bottleneck in the temporal dimension, particularly when taking a large number of time steps. The XBraid parallel-in-time library was developed as a practical way to add temporal parallelism to existing se- quential codes with only minor modi cations. In this work, a rezoning-type moving mesh is applied to a di usion problem and formulated in a parallel-in-time framework. Tests and scaling studies are run using XBraid and demonstrate excellent results for the simple model problem considered herein.

  6. A Comparison of the Efficiency Between Fog Collecting Meshes (United States)

    Eljenholm, C. M.; Coffey, E. M.; Fernandez, D.; Hernandez, C.; Mairs, A. A.


    Precipitation is the most recognized source of water; however, significant amounts of water reside in the air in the form of fog. Standard fog collectors designed by Schemenauer (Schemenauer and Cereceda, 1993) utilize a 1.00 square meter of a specific polypropylene fabric called Coresa with a 35% Raschel shade coefficient to capture and coalesce tiny fog droplets into larger drops that fall into a trough and are measured by a tipping bucket rain gauge. In this study, we compare three different types of mesh; the Chilean Coresa mesh mentioned above, a German mesh called FogHa-Tin, and an optimized mesh designed at the Massachusetts Institute of Technology, a POSS-PEMA dipped metallic mesh (Park et al, 2013). These meshes vary greatly in composition, as well as price. In order to determine which mesh is most optimal for fog collection in a variety of meteorological conditions, standard collectors of each type described above with a mesh area of 1.00 square meter have been placed at five locations around central California with accompanying meteorological instrumentation. This project will report on the effectiveness of each of these passive fog collectors in conjunction with accompanying meteorological data.

  7. Scalable Video Streaming in Wireless Mesh Networks for Education (United States)

    Liu, Yan; Wang, Xinheng; Zhao, Liqiang


    In this paper, a video streaming system for education based on a wireless mesh network is proposed. A wireless mesh network is a self-organizing, self-managing and reliable intelligent network, which allows educators to deploy a network quickly. Video streaming plays an important role in this system for multimedia data transmission. This new…

  8. Capacity analysis of wireless mesh networks | Gumel | Nigerian ...

    African Journals Online (AJOL)

    ... number of nodes (n) in a linear topology. The degradation is found to be higher in a fully mesh network as a result of increase in interference and MAC layer contention in the network. Key words: Wireless mesh network (WMN), Adhoc network, Network capacity analysis, Bottleneck collision domain, Medium access control ...

  9. Lagrangian fluid dynamics using the Voronoi-Delauanay mesh

    International Nuclear Information System (INIS)

    Dukowicz, J.K.


    A Lagrangian technique for numerical fluid dynamics is described. This technique makes use of the Voronoi mesh to efficiently locate new neighbors, and it uses the dual (Delaunay) triangulation to define computational cells. This removes all topological restrictions and facilitates the solution of problems containing interfaces and multiple materials. To improve computational accuracy a mesh smoothing procedure is employed

  10. The application of TINA in the MESH project

    NARCIS (Netherlands)

    van Sinderen, Marten J.; Ferreira Pires, Luis; Pires, L.F.; Plagemann, Thomas; Goebel, Vera


    This paper discusses the application of TINA concepts, architectures and related design paradigms in the MESH project. MESH adopted TINA as a means to facilitate the design and implementation of a flexible platform for developing and providing interactive multimedia services. This paper reports on

  11. Sen migration af mesh til colon efter laparoskopisk hernieoperation

    DEFF Research Database (Denmark)

    Rasmussen, Martin; Bisgaard, Thue


    Long-term complications after laparoscopic ventral hernia repair with mesh reinforcement are not well documented in the literature. We describe a case of a 63-year-old woman with repeated hernia operations due to a ventral hernia, which ultimately was complicated with mesh migration...

  12. Late mesh migration into the colon after laparoscopic herniotomy

    DEFF Research Database (Denmark)

    Rasmussen, Martin; Bisgaard, Thue


    Long-term complications after laparoscopic ventral hernia repair with mesh reinforcement are not well documented in the literature. We describe a case of a 63-year-old woman with repeated hernia operations due to a ventral hernia, which ultimately was complicated with mesh migration...

  13. Tangle-Free Finite Element Mesh Motion for Ablation Problems (United States)

    Droba, Justin


    In numerical simulations involving boundaries that evolve in time, the primary challenge is updating the computational mesh to reflect the physical changes in the domain. In particular, the fundamental objective for any such \\mesh motion" scheme is to maintain mesh quality and suppress unphysical geometric anamolies and artifacts. External to a physical process of interest, mesh motion is an added component that determines the specifics of how to move the mesh given certain limited information from the main system. This paper develops a set of boundary conditions designed to eliminate tangling and internal collision within the context of PDE-based mesh motion (linear elasticity). These boundary conditions are developed for two- and three-dimensional meshes. The paper presents detailed algorithms for commonly occuring topological scenarios and explains how to apply them appropriately. Notably, the techniques discussed herein make use of none of the specifics of any particular formulation of mesh motion and thus are more broadly applicable. The two-dimensional algorithms are validated by an extensive verification procedure. Finally, many examples of diverse geometries in both two- and three-dimensions are shown to showcase the capabilities of the tangle-free boundary conditions.

  14. Macrophage polarization in response to ECM coated polypropylene mesh. (United States)

    Wolf, Matthew T; Dearth, Christopher L; Ranallo, Christian A; LoPresti, Samuel T; Carey, Lisa E; Daly, Kerry A; Brown, Bryan N; Badylak, Stephen F


    The host response to implanted biomaterials is a highly regulated process that influences device functionality and clinical outcome. Non-degradable biomaterials, such as knitted polypropylene mesh, frequently elicit a chronic foreign body reaction with resultant fibrosis. Previous studies have shown that an extracellular matrix (ECM) hydrogel coating of polypropylene mesh reduces the intensity of the foreign body reaction, though the mode of action is unknown. Macrophage participation plays a key role in the development of the foreign body reaction to biomaterials, and therefore the present study investigated macrophage polarization following mesh implantation. Spatiotemporal analysis of macrophage polarization was conducted in response to uncoated polypropylene mesh and mesh coated with hydrated and dry forms of ECM hydrogels derived from either dermis or urinary bladder. Pro-inflammatory M1 macrophages (CD86+/CD68+), alternatively activated M2 macrophages (CD206+/CD68+), and foreign body giant cells were quantified between 3 and 35 days. Uncoated polypropylene mesh elicited a dominant M1 response at the mesh fiber surface, which was decreased by each ECM coating type beginning at 7 days. The diminished M1 response was accompanied by a reduction in the number of foreign body giant cells at 14 and 35 days, though there was a minimal effect upon the number of M2 macrophages at any time. These results show that ECM coatings attenuate the M1 macrophage response and increase the M2/M1 ratio to polypropylene mesh in vivo. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Micro-mesh fabric pollination bags for switchgrass (United States)

    Pollination bags for making controlled crosses between switchgrass plants were made from a polyester micro-mesh fabric with a mesh size of 41 µm which is smaller than the mean reported 43 µm diameter of switchgrass pollen. When used in paired plant crosses between switchgrass plants, the mean amoun...

  16. Adaptive mesh generation for image registration and segmentation

    DEFF Research Database (Denmark)

    Fogtmann, Mads; Larsen, Rasmus


    measure. The method was tested on a T1 weighted MR volume of an adult brain and showed a 66% reduction in the number of mesh vertices compared to a red-subdivision strategy. The deformation capability of the mesh was tested by registration to five additional T1-weighted MR volumes....


    African Journals Online (AJOL)

    VARIABLE MESH STIFFNESS OF SPUR GEAR TEETH USING. FINITE ELEMENT METHOD. Yonatan Afework and Tamrat Tesfaye. Depaliment of Mechanical Engineering. Addis Ababa University. ABSTRACT. The ohiective of this paper is to determine the variahle mesh s/rJlness of spur gear teeth using the finite element ...

  18. Energy mesh optimization for multi-level calculation schemes

    International Nuclear Information System (INIS)

    Mosca, P.; Taofiki, A.; Bellier, P.; Prevost, A.


    The industrial calculations of third generation nuclear reactors are based on sophisticated strategies of homogenization and collapsing at different spatial and energetic levels. An important issue to ensure the quality of these calculation models is the choice of the collapsing energy mesh. In this work, we show a new approach to generate optimized energy meshes starting from the SHEM 281-group library. The optimization model is applied on 1D cylindrical cells and consists of finding an energy mesh which minimizes the errors between two successive collision probability calculations. The former is realized over the fine SHEM mesh with Livolant-Jeanpierre self-shielded cross sections and the latter is performed with collapsed cross sections over the energy mesh being optimized. The optimization is done by the particle swarm algorithm implemented in the code AEMC and multigroup flux solutions are obtained from standard APOLLO2 solvers. By this new approach, a set of new optimized meshes which encompass from 10 to 50 groups has been defined for PWR and BWR calculations. This set will allow users to adapt the energy detail of the solution to the complexity of the calculation (assembly, multi-assembly, two-dimensional whole core). Some preliminary verifications, in which the accuracy of the new meshes is measured compared to a direct 281-group calculation, show that the 30-group optimized mesh offers a good compromise between simulation time and accuracy for a standard 17 x 17 UO 2 assembly with and without control rods. (author)

  19. Mesh Processing in Medical-Image Analysis-a Tutorial

    DEFF Research Database (Denmark)

    Levine, Joshua A.; Paulsen, Rasmus Reinhold; Zhang, Yongjie


    Medical-image analysis requires an understanding of sophisticated scanning modalities, constructing geometric models, building meshes to represent domains, and downstream biological applications. These four steps form an image-to-mesh pipeline. For research in this field to progress, the imaging,...

  20. Balanced monitoring of flow phenomena in moving mesh methods

    NARCIS (Netherlands)

    van Dam, A.; Zegeling, P.A.


    Adaptive moving mesh research usually focuses either on analytical derivations for prescribed solutions or on pragmatic solvers with challenging physical applications. In the latter case, the monitor functions that steer mesh adaptation are often defined in an ad-hoc way. In this paper we generalize

  1. Surface Mesh Reconstruction from Cardiac MRI Contours

    Directory of Open Access Journals (Sweden)

    Benjamin Villard


    Full Text Available We introduce a tool to build a surface mesh able to deal with sparse, heterogeneous, non-parallel, cross-sectional, non-coincidental contours and show its application to reconstruct surfaces of the heart. In recent years, much research has looked at creating personalised 3D anatomical models of the heart. These models usually incorporate a geometrical reconstruction of the anatomy in order to better understand cardiovascular functions as well as predict different cardiac processes. As MRIs are becoming the standard for cardiac medical imaging, we tested our methodology on cardiac MRI data from standard acquisitions. However, the ability to accurately reconstruct heart anatomy in three dimensions commonly comes with fundamental challenges—notably, the trade-off between data fitting and expected visual appearance. Most current techniques can either require contours from parallel slices or, if multiple slice orientations are used, require an exact match between these contours. In addition, some methods introduce a bias by the use of prior shape models or by trade-offs between the data matching terms and the smoothing terms. Our approach uses a composition of smooth approximations towards the maximization of the data fitting, ensuring a good matching to the input data as well as pleasant interpolation characteristics. To assess our method in the task of cardiac mesh generations, we evaluated its performance on synthetic data obtained from a cardiac statistical shape model as well as on real data. Using a statistical shape model, we simulated standard cardiac MRI acquisitions planes and contour data. We performed a multi-parameter evaluation study using plausible cardiac shapes generated from the model. We also show that long axes contours as well as the most extremal slices (basal and apical contain the most amount of structural information, and thus should be taken into account when generating anatomically relevant geometrical cardiovascular

  2. Mesh Inguinal Hernia Repair and Appendectomy in the Treatment of Amyand's Hernia with Non-Inflamed Appendices (United States)

    Kose, Emin; Sisik, Abdullah


    Amyand's hernia is defined as protrusion of the vermiform appendix in an inguinal hernia sac. It is a rare entity with variable clinical presentation from normal vermiform appendix to abscess formation due to perforation of acute appendicitis. Although surgical treatment includes appendectomy and hernia repair, appendectomy in the absence of an inflamed appendix and use of a mesh in cases of appendectomy remain to be controversial. The aim of this study was to review the experience of mesh inguinal hernia repair plus appendectomy performed for Amyand's hernia with noninflamed appendices. There were five male patients with a mean age of 42.4 ± 16.1 years in this retrospective study in which Amyand's hernia was treated with mesh inguinal hernia repair plus appendectomy for noninflamed appendices. Patients with acute appendicitis and perforated vermiform appendix were excluded. There were four right sided and one bilateral inguinal hernia. Postoperative courses were uneventful. During the follow-up period (14.0 ± 7.7 months), there was no inguinal hernia recurrence. Mesh inguinal hernia repair with appendectomy can be performed for Amyand's hernia in the absence of acute appendicitis. However, presence of fibrous connections between the vermiform appendix and the surrounding hernia sac may be regarded as a parameter to perform appendectomy. PMID:28194430

  3. Mesh Inguinal Hernia Repair and Appendectomy in the Treatment of Amyand’s Hernia with Non-Inflamed Appendices

    Directory of Open Access Journals (Sweden)

    Emin Kose


    Full Text Available Amyand’s hernia is defined as protrusion of the vermiform appendix in an inguinal hernia sac. It is a rare entity with variable clinical presentation from normal vermiform appendix to abscess formation due to perforation of acute appendicitis. Although surgical treatment includes appendectomy and hernia repair, appendectomy in the absence of an inflamed appendix and use of a mesh in cases of appendectomy remain to be controversial. The aim of this study was to review the experience of mesh inguinal hernia repair plus appendectomy performed for Amyand’s hernia with noninflamed appendices. There were five male patients with a mean age of 42.4 ± 16.1 years in this retrospective study in which Amyand’s hernia was treated with mesh inguinal hernia repair plus appendectomy for noninflamed appendices. Patients with acute appendicitis and perforated vermiform appendix were excluded. There were four right sided and one bilateral inguinal hernia. Postoperative courses were uneventful. During the follow-up period (14.0 ± 7.7 months, there was no inguinal hernia recurrence. Mesh inguinal hernia repair with appendectomy can be performed for Amyand’s hernia in the absence of acute appendicitis. However, presence of fibrous connections between the vermiform appendix and the surrounding hernia sac may be regarded as a parameter to perform appendectomy.

  4. Use of mesh in laparoscopic paraesophageal hernia repair

    DEFF Research Database (Denmark)

    Müller-Stich, Beat P.; Kenngott, Hannes G.; Gondan, Matthias


    Introduction. Mesh augmentation seems to reduce recurrences following laparoscopic paraesophageal hernia repair (LPHR). However, there is an uncertain risk of mesh-associated complications. Risk-benefit analysis might solve the dilemma. Materials and Methods. A systematic literature search...... was performed to identify randomized controlled trials (RCTs) and observational clinical studies (OCSs) comparing laparoscopic mesh-augmented hiatoplasty (LMAH) with laparoscopic mesh-free hiatoplasty (LH) with regard to recurrences and complications. Random effects meta-analyses were performed to determine...... potential benefits of LMAH. All data regarding LMAH were used to estimate risk of mesh-associated complications. Risk-benefit analysis was performed using a Markov Monte Carlo decision-analytic model. Results. Meta-analysis of 3 RCTs and 9 OCSs including 915 patients revealed a significantly lower...

  5. Challenges in Second-Generation Wireless Mesh Networks

    Directory of Open Access Journals (Sweden)

    Pescapé Antonio


    Full Text Available Wireless mesh networks have the potential to provide ubiquitous high-speed Internet access at low costs. The good news is that initial deployments of WiFi meshes show the feasibility of providing ubiquitous Internet connectivity. However, their performance is far below the necessary and achievable limit. Moreover, users' subscription in the existing meshes is dismal even though the technical challenges to get connectivity are low. This paper provides an overview of the current status of mesh networks' deployment, and highlights the technical, economical, and social challenges that need to be addressed in the next years. As a proof-of-principle study, we discuss the above-mentioned challenges with reference to three real networks: (i MagNets, an operator-driven planned two-tier mesh network; (ii Berlin Freifunk network as a pure community-driven single-tier network; (iii Weimar Freifunk network, also a community-driven but two-tier network.

  6. Challenges in Second-Generation Wireless Mesh Networks

    Directory of Open Access Journals (Sweden)

    Thomas Huehn


    Full Text Available Wireless mesh networks have the potential to provide ubiquitous high-speed Internet access at low costs. The good news is that initial deployments of WiFi meshes show the feasibility of providing ubiquitous Internet connectivity. However, their performance is far below the necessary and achievable limit. Moreover, users' subscription in the existing meshes is dismal even though the technical challenges to get connectivity are low. This paper provides an overview of the current status of mesh networks' deployment, and highlights the technical, economical, and social challenges that need to be addressed in the next years. As a proof-of-principle study, we discuss the above-mentioned challenges with reference to three real networks: (i MagNets, an operator-driven planned two-tier mesh network; (ii Berlin Freifunk network as a pure community-driven single-tier network; (iii Weimar Freifunk network, also a community-driven but two-tier network.

  7. Construction of the Voronoi mesh on a sphere

    International Nuclear Information System (INIS)

    Augenbaum, J.M.; Peskin, C.S.


    A new construction of the Voronoi mesh on the sphere is presented. The main feature is that the algorithm adds points one at a time until the final Voronoi mesh is built up. By adding one point to an existing Voronoi mesh of K points, only local changes are needed to construct a Voronoi mesh of K+1 points. This construction is particularly well suited to time-dependent problems since using information from the Voronoi mesh at the previous time step allows us to reduce the construction to O(N) operations when the two configurations are close, while the algorithm does not break down when they are far apart. Numerical experiments are presented to substantiate the O(N) operation count for a ''typical'' case

  8. A coarse-mesh nodal method-diffusive-mesh finite difference method

    International Nuclear Information System (INIS)

    Joo, H.; Nichols, W.R.


    Modern nodal methods have been successfully used for conventional light water reactor core analyses where the homogenized, node average cross sections (XSs) and the flux discontinuity factors (DFs) based on equivalence theory can reliably predict core behavior. For other types of cores and other geometries characterized by tightly-coupled, heterogeneous core configurations, the intranodal flux shapes obtained from a homogenized nodal problem may not accurately portray steep flux gradients near fuel assembly interfaces or various reactivity control elements. This may require extreme values of DFs (either very large, very small, or even negative) to achieve a desired solution accuracy. Extreme values of DFs, however, can disrupt the convergence of the iterative methods used to solve for the node average fluxes, and can lead to a difficulty in interpolating adjacent DF values. Several attempts to remedy the problem have been made, but nothing has been satisfactory. A new coarse-mesh nodal scheme called the Diffusive-Mesh Finite Difference (DMFD) technique, as contrasted with the coarse-mesh finite difference (CMFD) technique, has been developed to resolve this problem. This new technique and the development of a few-group, multidimensional kinetics computer program are described in this paper

  9. Robust, multidimensional mesh motion based on Monge-Kantorovich equidistribution

    Energy Technology Data Exchange (ETDEWEB)

    Delzanno, G L [Los Alamos National Laboratory; Finn, J M [Los Alamos National Laboratory


    Mesh-motion (r-refinement) grid adaptivity schemes are attractive due to their potential to minimize the numerical error for a prescribed number of degrees of freedom. However, a key roadblock to a widespread deployment of the technique has been the formulation of robust, reliable mesh motion governing principles, which (1) guarantee a solution in multiple dimensions (2D and 3D), (2) avoid grid tangling (or folding of the mesh, whereby edges of a grid cell cross somewhere in the domain), and (3) can be solved effectively and efficiently. In this study, we formulate such a mesh-motion governing principle, based on volume equidistribution via Monge-Kantorovich optimization (MK). In earlier publications [1, 2], the advantages of this approach in regards to these points have been demonstrated for the time-independent case. In this study, demonstrate that Monge-Kantorovich equidistribution can in fact be used effectively in a time stepping context, and delivers an elegant solution to the otherwise pervasive problem of grid tangling in mesh motion approaches, without resorting to ad-hoc time-dependent terms (as in moving-mesh PDEs, or MMPDEs [3, 4]). We explore two distinct r-refinement implementations of MK: direct, where the current mesh relates to an initial, unchanging mesh, and sequential, where the current mesh is related to the previous one in time. We demonstrate that the direct approach is superior in regards to mesh distortion and robustness. The properties of the approach are illustrated with a paradigmatic hyperbolic PDE, the advection of a passive scalar. Imposed velocity flow fields or varying vorticity levels and flow shears are considered.

  10. Open and laparo-endoscopic repair of incarcerated abdominal wall hernias by the use of biological and biosynthetic meshes

    Directory of Open Access Journals (Sweden)

    René H Fortelny


    Full Text Available Introduction: Although recently published guidelines recommend against the use of synthetic non-absorbable materials in cases of potentially contaminated or contaminated surgical fields due to the increased risk of infection [1, 2], the use of bio-prosthetic meshes for abdominal wall or ventral hernia repair is still controversially discussed in such cases. Bio-prosthetic meshes have been recommended due to less susceptibility for infection and the decreased risk of subsequent mesh explantation. The purpose of this review is to elucidate if there are any indications for the use of biological and biosynthetic meshes in incarcerated abdominal wall hernias based on the recently published literature.Methods: A literature search of the Medline database using the PubMed search engine, using the keywords returned 486 articles up to June 2015. The full text of 486 articles was assessed and 13 relevant papers were identified including 5 retrospective case cohort studies, 2 case controlled studies, 6 case series.Results: The results of Franklin et al [23, 24, 25] included the highest number of biological mesh repairs (Surgisis® by laparoscopic IPOM in infected fields which demonstrated a very low incidence of infection and recurrence (0,7% and 5,2%. Han et al [26] reported in his retrospective study the highest number of treated patients due to incarcerated hernias by open approach using acellular dermal matrix (ADM® with very low rate of infection as well as recurrences (1,6% and 15,9. Both studies achieved acceptable outcome in a follow up of at least 3,5 years compared to the use of synthetic mesh in this high-risk population [3]Conclusion:Currently there is a very limited evidence for the use of biological and biosynthetic meshes in strangulated hernias in either open or laparo-endoscopic repair. Finally, there is an urgent need to start with randomized controlled comparative trials as well as to support registries with data to achieve more

  11. In-vitro examination of the biocompatibility of fibroblast cell lines on alloplastic meshes and sterilized polyester mosquito mesh. (United States)

    Wiessner, R; Kleber, T; Ekwelle, N; Ludwig, K; Richter, D-U


    The use of alloplastic implants for tissue strengthening when treating hernias is an established therapy worldwide. Despite the high incidence of hernias in Africa and Asia, the implantation of costly mesh netting is not financially feasible. Because of that various investigative groups have examined the use of sterilized mosquito netting. The animal experiments as well as the clinical trials have both shown equivalent short- and long-term results. The goal of this paper is the comparison of biocompatibility of human fibroblasts on the established commercially available nets and on sterilized polyester mosquito mesh over a period of 12 weeks. Three commercially available plastic mesh types and a gas-sterilized mosquito polyethylenterephtalate (polyester) mesh were examined. Human fibroblasts from subcutaneous healthy tissue were used. Various tests for evaluating the growth behavior and the cell morphology of human fibroblasts were conducted. The semi-quantitative (light microscopy) and qualitative (scanning electron microscopy) analyses were performed after 1 week and then again after 12 weeks. The cell proliferation and cytotoxicity of the implants were investigated with the help of the 5'-bromo-2'-deoxyuridine (BrdU)-cell proliferation test and the LDH-cytotoxicity test. The number of live cells per ml was determined with the Bürker counting chamber. In addition, analyses were made of the cell metabolism (oxidative stress) by measuring the pH value, hydrogen peroxide, and glycolysis. After 12 weeks, a proliferation of fibroblasts on all mesh is documented. No mesh showed a complete apoptosis of the cells. This qualitative observation could be confirmed quantitatively in a biochemical assay by marking the proliferating cells with BrdU. The biochemical analysis brought the proof that the materials used, including the polyester of the mosquito mesh, are not cytotoxic for the fibroblasts. The vitality of the cells was between 94 and 98%. The glucose metabolism

  12. Distribution of isodose curves in urological surgical procedures

    International Nuclear Information System (INIS)

    Lanfredi, M.P.; Dias, J.H.; Ravazio, R.C.; Anés, M.; Bacelar, A.; Lykawka, R.


    During urological surgical procedures with fluoroscopy, the doses of the care team may be significant. However, the knowledge of the occupational exposure of these professionals is still very incipient in the national surgical centers. The objective of the study is to determine the isodose curves of the urological surgical procedures, in order to estimate the exposure of the personnel involved. The equipment used was a Arco-C BV Philips Bracelet. Patients with thicknesses of 20 and 28 cm were simulated using acrylic plates. The dose rates were measured with RaySafe i2 Unfors dosimeters positioned in a 50 x 50 cm mesh at three different heights of the floor: 95, 125 and 165 centimeters respectively corresponding to the gonadal, thoracic and crystalline regions of a typical adult . The isodose curves applied to the distribution of the surgical team suggest that the exposures are in the following descending order of intensity: primary physician, auxiliary physician, scrub nurse, anesthetist and nurse

  13. Micro-surgical endodontics. (United States)

    Eliyas, S; Vere, J; Ali, Z; Harris, I


    Non-surgical endodontic retreatment is the treatment of choice for endodontically treated teeth with recurrent or residual disease in the majority of cases. In some cases, surgical endodontic treatment is indicated. Successful micro-surgical endodontic treatment depends on the accuracy of diagnosis, appropriate case selection, the quality of the surgical skills, and the application of the most appropriate haemostatic agents and biomaterials. This article describes the armamentarium and technical procedures involved in performing micro-surgical endodontics to a high standard.

  14. Outcomes with porcine acellular dermal matrix versus synthetic mesh and suture in complicated open ventral hernia repair. (United States)

    Liang, Mike K; Berger, Rachel L; Nguyen, Mylan Thi; Hicks, Stephanie C; Li, Linda T; Leong, Mimi


    Mesh reinforcement as part of open ventral hernia repair (OVHR) has become the standard of care. However, there is no consensus on the ideal type of mesh to use. In many clinical situations, surgeons are reluctant to use synthetic mesh. Options in these complicated OVHRs include suture repair or the use of biologic mesh such as porcine acellular dermal matrix (PADM). There has been a paucity of controlled studies reporting long-term outcomes with biologic meshes. We hypothesized that compared with synthetic mesh in OVHR, PADM is associated with fewer surgical site infections (SSI) but more seromas and recurrences. Additionally, compared with suture repair, we hypothesized that PADM is associated with fewer recurrences but more SSIs and seromas. A retrospective study was performed of all complicated OVHRs performed at a single institution from 2000-2011. All data were captured from the electronic medical records of the service network. Data were compared in two ways. First, patients who had OVHR with PADM were case-matched with patients having synthetic mesh repairs on the basis of incision class, Ventral Hernia Working Group (VHWG) grade, hernia size, American Society of Anesthesiologists (ASA) class, and emergency status. The PADM cases were also matched with suture repairs on the basis of incision class, hernia grade, duration of the operation, ASA class, and emergency status. Second, we developed a propensity score-adjusted multi-variable logistic regression model utilizing internal resampling to identify predictors of primary outcomes of the overall cohort. The U.S. Centers for Disease Control and Prevention (CDC) definition of SSI was utilized; seromas and recurrences were defined and tracked similarly for all patients. Data were analyzed using the McNemar, X(2), paired two-tailed Student t, or Mann-Whitney U test as appropriate. A total of 449 complicated OVHR cases were reviewed for a median follow up of 61 mos (range 1-143 mos): 94 patients had PADM

  15. Three-Year Results of a Single-Centre Single-Blinded Randomised Study Evaluating the Impact of Mesh Pore Size on Chronic Pain after Lichtenstein Hernioplasty. (United States)

    Nikkolo, C; Vaasna, T; Murruste, M; Seepter, H; Kirsimägi, Ü; Lepner, U


    both meshes used in our study. © The Finnish Surgical Society 2016.

  16. Design Investigation on Applicable Mesh Structures for Medical Stent Applications (United States)

    Asano, Shoji; He, Jianmei


    In recent years, utilization of medical stents is one of effective treatments for stenosis and occlusion occurring in a living body’s lumen indispensable for maintenance of human life such as superficial femoral artery (SFA) occlusion. However, there are concerns about the occurrence of fatigue fractures caused by stress concentrations, neointimal hyperplasia and the like due to the shape structure and the manufacturing method in the conventional stents, and a stent having high strength and high flexibility is required. Therefore, in this research, applicable mesh structures for medical stents based on the design concepts of high strength, high flexibility are interested to solve various problem of conventional stent. According to the shape and dimensions of SFA occlusion therapy stent and indwelling delivery catheter, shape design of the meshed stent are performed using 3-dimensional CAD software Solid Works first. Then analytical examination on storage characteristics and compression characteristics of such mesh structure applied stent models were carried out through finite element analysis software ANSYS Workbench. Meshed stent models with higher strength and higher flexibility with integral molding are investigated analytically. It was found that the storage characteristics and compression characteristics of meshed stent modles are highly dependent on the basic mesh shapes with same surface void ratio. Trade-off relationship between flexibility and storage characteristics is found exited, it is required to provide appropriate curvatures during basic mesh shape design.

  17. Finite element simulation of impact response of wire mesh screens

    Directory of Open Access Journals (Sweden)

    Wang Caizheng


    Full Text Available In this paper, the response of wire mesh screens to low velocity impact with blunt objects is investigated using finite element (FE simulation. The woven wire mesh is modelled with homogeneous shell elements with equivalent smeared mechanical properties. The mechanical behaviour of the woven wire mesh was determined experimentally with tensile tests on steel wire mesh coupons to generate the data for the smeared shell material used in the FE. The effects of impacts with a low mass (4 kg and a large mass (40 kg providing the same impact energy are studied. The joint between the wire mesh screen and the aluminium frame surrounding it is modelled using contact elements with friction between the corresponding elements. Damage to the screen of different types compromising its structural integrity, such as mesh separation and pulling out from the surrounding frame is modelled. The FE simulation is validated with results of impact tests conducted on woven steel wire screen meshes.

  18. Does Attorney Advertising Influence Patient Perceptions of Pelvic Mesh? (United States)

    Tippett, Elizabeth; King, Jesse; Lucent, Vincent; Ephraim, Sonya; Murphy, Miles; Taff, Eileen


    To measure the relative influence of attorney advertising on patient perceptions of pelvic mesh compared with a history of surgery and a first urology visit. A 52-item survey was administered to 170 female patients in 2 urology offices between 2014 and 2016. Multiple survey items were combined to form scales for benefit and risk perceptions of pelvic mesh, perceptions of the advertising, attitudes toward pelvic mesh, and knowledge of pelvic mesh and underlying medical conditions. Data were analyzed using hierarchical linear regression models. Exposure to attorney advertising was quite high; 88% reported seeing a mesh-related attorney advertisement in the last 6 months. Over half of patients reported seeing attorney advertisements more than once per week. A history of prior mesh implant surgery was the strongest predictor of benefit and risk perceptions of pelvic mesh. Exposure to attorney advertising was associated with higher risk perceptions but did not significantly affect perceptions of benefits. Past urologist visits increased perceptions of benefits but had no effect on risk perceptions. Attorney advertising appears to have some influence on risk perceptions, but personal experience and discussions with a urogynecologist or urologist also influence patient perceptions. Implications, limitations, and future research are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. A Survey of Solver-Related Geometry and Meshing Issues (United States)

    Masters, James; Daniel, Derick; Gudenkauf, Jared; Hine, David; Sideroff, Chris


    There is a concern in the computational fluid dynamics community that mesh generation is a significant bottleneck in the CFD workflow. This is one of several papers that will help set the stage for a moderated panel discussion addressing this issue. Although certain general "rules of thumb" and a priori mesh metrics can be used to ensure that some base level of mesh quality is achieved, inadequate consideration is often given to the type of solver or particular flow regime on which the mesh will be utilized. This paper explores how an analyst may want to think differently about a mesh based on considerations such as if a flow is compressible vs. incompressible or hypersonic vs. subsonic or if the solver is node-centered vs. cell-centered. This paper is a high-level investigation intended to provide general insight into how considering the nature of the solver or flow when performing mesh generation has the potential to increase the accuracy and/or robustness of the solution and drive the mesh generation process to a state where it is no longer a hindrance to the analysis process.

  20. Three-dimensional motion and deformation estimation of deformable mesh (United States)

    Deknuydt, Albert A.; Desmet, Stefaan; Cox, Kris; Van Eycken, Luc


    Recently real-time capture of dynamic 3D-objects has become feasible. The dynamic models obtained by various techniques, come in the form of separate highly detailed 3D-meshes with texture at video-rates. These represent such an amount of data, as to hamper manipulation, editing and rendering. Data- compression techniques can alleviate this problem. Independent decimation of the separate meshes, is an inferior solution for what is really time varying mesh. Firstly, it causes unnatural flickering, and secondly, it leaves the inter-mesh correlation unexploited. Therefore, a hybrid technique might be a better solution. It consists of an 'intra' compression scheme working on still mesh, a 3D motion estimator/predictor, and a coder for the prediction errors and side information (motion vectors and mesh segmentation). We describe a technique to segment a deforming mesh into regions with locally-uniform motion. We start by interpreting the motion as samples of a 3D vector field. In each point, we estimate the translation, rotation and divergence of the vector field. As human faces are rather incompressible, we ignore the divergence component. Then, we cluster the population with the criterion of similar translation and rotation. Results show that it allows to segment a deforming human face into approximately 200 regions of locally-uniform rigid motion, while keeping the motion prediction error under 5 percent. This is good enough for efficient compression.

  1. Reaction rates for reaction-diffusion kinetics on unstructured meshes. (United States)

    Hellander, Stefan; Petzold, Linda


    The reaction-diffusion master equation is a stochastic model often utilized in the study of biochemical reaction networks in living cells. It is applied when the spatial distribution of molecules is important to the dynamics of the system. A viable approach to resolve the complex geometry of cells accurately is to discretize space with an unstructured mesh. Diffusion is modeled as discrete jumps between nodes on the mesh, and the diffusion jump rates can be obtained through a discretization of the diffusion equation on the mesh. Reactions can occur when molecules occupy the same voxel. In this paper, we develop a method for computing accurate reaction rates between molecules occupying the same voxel in an unstructured mesh. For large voxels, these rates are known to be well approximated by the reaction rates derived by Collins and Kimball, but as the mesh is refined, no analytical expression for the rates exists. We reduce the problem of computing accurate reaction rates to a pure preprocessing step, depending only on the mesh and not on the model parameters, and we devise an efficient numerical scheme to estimate them to high accuracy. We show in several numerical examples that as we refine the mesh, the results obtained with the reaction-diffusion master equation approach those of a more fine-grained Smoluchowski particle-tracking model.

  2. The effect of music on robot-assisted laparoscopic surgical performance. (United States)

    Siu, Ka-Chun; Suh, Irene H; Mukherjee, Mukul; Oleynikov, Dmitry; Stergiou, Nick


    Music is often played in the operating room to increase the surgeon's concentration and to mask noise. It could have a beneficial effect on surgical performance. Ten participants with limited experience with the da Vinci robotic surgical system were recruited to perform two surgical tasks: suture tying and mesh alignment when classical, jazz, hip-hop, and Jamaican music were presented. Kinematics of the instrument tips of the surgical robot and surface electromyography of the subjects were recorded. Results revealed that a significant music effect was found for both tasks with decreased time to task completion (P = .005) and total travel distance (P = .021) as well as reduced muscle activations ( P = .016) and increased median muscle frequency (P = .034). Subjects improved their performance significantly when they listened to either hip-hop or Jamaican music. In conclusion, music with high rhythmicity has a beneficial effect on robotic surgical performance. Musical environment may benefit surgical training and make acquisition of surgical skills more efficient.

  3. r-Adaptive mesh generation for shell finite element analysis

    International Nuclear Information System (INIS)

    Cho, Maenghyo; Jun, Seongki


    An r-adaptive method or moving grid technique relocates a grid so that it becomes concentrated in the desired region. This concentration improves the accuracy and efficiency of finite element solutions. We apply the r-adaptive method to computational mesh of shell surfaces, which is initially regular and uniform. The r-adaptive method, given by Liao and Anderson [Appl. Anal. 44 (1992) 285], aggregate the grid in the region with a relatively high weight function without any grid-tangling. The stress error estimator is calculated in the initial uniform mesh for a weight function. However, since the r-adaptive method is a method that moves the grid, shell surface geometry error such as curvature error and mesh distortion error will increase. Therefore, to represent the exact geometry of a shell surface and to prevent surface geometric errors, we use the Naghdi's shell theory and express the shell surface by a B-spline patch. In addition, using a nine-node element, which is relatively less sensitive to mesh distortion, we try to diminish mesh distortion error in the application of an r-adaptive method. In the numerical examples, it is shown that the values of the error estimator for a cylinder, hemisphere, and torus in the overall domain can be reduced effectively by using the mesh generated by the r-adaptive method. Also, the reductions of the estimated relative errors are demonstrated in the numerical examples. In particular, a new functional is proposed to construct an adjusted mesh configuration by considering a mesh distortion measure as well as the stress error function. The proposed weight function provides a reliable mesh adaptation method after a parameter value in the weight function is properly chosen

  4. Recognition of Handwritten Character by Fuzzy Neighbor Mesh Feature


    "王,暁文/橋本,禮治"; "/ハシモト, レイジ"; "Wang,Xiaowen/Hashimoto,Reiji"


    "The fuzzy mesh feature (FM-feature) which is proposed in our previous work has been proved that it can absorb some handwriting variation. But the recognition rate got there is still not sufficient, one reason of which may be that this feature includes limited structural information about the character. In this work, we consider a modified fuzzy feature of mesh pattern (FNM-feature) by utilizing the neighbor meshes. And by the experiment about that, we have got the result that FNM-feature imp...

  5. Expected Transmission Energy Route Metric for Wireless Mesh Senor Networks

    Directory of Open Access Journals (Sweden)

    YanLiang Jin


    Full Text Available Mesh is a network topology that achieves high throughput and stable intercommunication. With great potential, it is expected to be the key architecture of future networks. Wireless sensor networks are an active research area with numerous workshops and conferences arranged each year. The overall performance of a WSN highly depends on the energy consumption of the network. This paper designs a new routing metric for wireless mesh sensor networks. Results from simulation experiments reveal that the new metric algorithm improves the energy balance of the whole network and extends the lifetime of wireless mesh sensor networks (WMSNs.

  6. Vertex Normals and Face Curvatures of Triangle Meshes

    KAUST Repository

    Sun, Xiang


    This study contributes to the discrete differential geometry of triangle meshes, in combination with discrete line congruences associated with such meshes. In particular we discuss when a congruence defined by linear interpolation of vertex normals deserves to be called a ʼnormal’ congruence. Our main results are a discussion of various definitions of normality, a detailed study of the geometry of such congruences, and a concept of curvatures and shape operators associated with the faces of a triangle mesh. These curvatures are compatible with both normal congruences and the Steiner formula.

  7. Isotropic 2D quadrangle meshing with size and orientation control

    KAUST Repository

    Pellenard, Bertrand


    We propose an approach for automatically generating isotropic 2D quadrangle meshes from arbitrary domains with a fine control over sizing and orientation of the elements. At the heart of our algorithm is an optimization procedure that, from a coarse initial tiling of the 2D domain, enforces each of the desirable mesh quality criteria (size, shape, orientation, degree, regularity) one at a time, in an order designed not to undo previous enhancements. Our experiments demonstrate how well our resulting quadrangle meshes conform to a wide range of input sizing and orientation fields.

  8. Engagement of Metal Debris into a Gear Mesh (United States)

    Handschuh, Robert F.; Krantz, Timothy L.


    A series of bench top experiments was conducted to determine the effects of metallic debris being dragged through meshing gear teeth. A test rig that is typically used to conduct contact fatigue experiments was used for these tests. Several sizes of drill material, shim stock, and pieces of gear teeth were introduced and then driven through the meshing region. The level of torque required to drive the "chip" through the gear mesh was measured. From the data gathered, chip size sufficient to jam the mechanism can be determined.

  9. Procedure for the automatic mesh generation of innovative gear teeth

    Directory of Open Access Journals (Sweden)

    Radicella Andrea Chiaramonte


    Full Text Available After having described gear wheels with teeth having the two sides constituted by different involutes and their importance in engineering applications, we stress the need for an efficient procedure for the automatic mesh generation of innovative gear teeth. First, we describe the procedure for the subdivision of the tooth profile in the various possible cases, then we show the method for creating the subdivision mesh, defined by two series of curves called meridians and parallels. Finally, we describe how the above procedure for automatic mesh generation is able to solve specific cases that may arise when dealing with teeth having the two sides constituted by different involutes.

  10. Numerical convergence of discrete exterior calculus on arbitrary surface meshes

    KAUST Repository

    Mohamed, Mamdouh S.


    Discrete exterior calculus (DEC) is a structure-preserving numerical framework for partial differential equations solution, particularly suitable for simplicial meshes. A longstanding and widespread assumption has been that DEC requires special (Delaunay) triangulations, which complicated the mesh generation process especially for curved surfaces. This paper presents numerical evidence demonstrating that this restriction is unnecessary. Convergence experiments are carried out for various physical problems using both Delaunay and non-Delaunay triangulations. Signed diagonal definition for the key DEC operator (Hodge star) is adopted. The errors converge as expected for all considered meshes and experiments. This relieves the DEC paradigm from unnecessary triangulation limitation.

  11. Hex-dominant mesh generation using 3D constrained triangulation

    Energy Technology Data Exchange (ETDEWEB)



    A method for decomposing a volume with a prescribed quadrilateral surface mesh, into a hexahedral-dominated mesh is proposed. With this method, known as Hex-Morphing (H-Morph), an initial tetrahedral mesh is provided. Tetrahedral are transformed and combined starting from the boundary and working towards the interior of the volume. The quadrilateral faces of the hexahedra are treated as internal surfaces, which can be recovered using constrained triangulation techniques. Implementation details of the edge and face recovery process are included. Examples and performance of the H-Morph algorithm are also presented.

  12. Fair packet scheduling in Wireless Mesh Networks

    KAUST Repository

    Nawab, Faisal


    In this paper we study the interactions of TCP and IEEE 802.11 MAC in Wireless Mesh Networks (WMNs). We use a Markov chain to capture the behavior of TCP sessions, particularly the impact on network throughput due to the effect of queue utilization and packet relaying. A closed form solution is derived to numerically determine the throughput. Based on the developed model, we propose a distributed MAC protocol called Timestamp-ordered MAC (TMAC), aiming to alleviate the unfairness problem in WMNs. TMAC extends CSMA/CA by scheduling data packets based on their age. Prior to transmitting a data packet, a transmitter broadcasts a request control message appended with a timestamp to a selected list of neighbors. It can proceed with the transmission only if it receives a sufficient number of grant control messages from these neighbors. A grant message indicates that the associated data packet has the lowest timestamp of all the packets pending transmission at the local transmit queue. We demonstrate that a loose ordering of timestamps among neighboring nodes is sufficient for enforcing local fairness, subsequently leading to flow rate fairness in a multi-hop WMN. We show that TMAC can be implemented using the control frames in IEEE 802.11, and thus can be easily integrated in existing 802.11-based WMNs. Our simulation results show that TMAC achieves excellent resource allocation fairness while maintaining over 90% of maximum link capacity across a large number of topologies.

  13. Surgical handicraft: teaching and learning surgical skills. (United States)

    Barnes, R W


    Surgeons choose their profession with a strong desire to excel at manual therapeutic skills. Although we mime our mentors, we have often received the torch of technique in the absence of a systematic program to optimally develop our manual dexterity. The operating room is the ultimate arena to refine one's technical ability, but a surgical skills laboratory should assume increasing importance in introducing the trainee to the many nuances of the fine manual motor skills necessary for optimal surgical technique. Surgical educators should address the science of surgical handicraft in a manner similar to the science of preoperative and postoperative surgical principles that have been espoused over the past 40 years. Although it has been euphemistically said that "you can teach a monkey to operate," few of us have broken the process down into the basic elements to accomplish such a goal. In view of the increasing complexity of operations and equipment, the constraints on animal laboratories and teaching caseloads, and the mounting economic and medico-legal pressures, the development of optimal surgical skills should be a major objective of every surgical training program. By developing novel programs and scientifically evaluating the results of such endeavors, surgical faculties may find increased academic rewards for being a good teacher.

  14. Follow-up of mesh complications using the IUGA/ICS category-time-site coding classification. (United States)

    Bontje, H F; van de Pol, G; van der Zaag-Loonen, H J; Spaans, W A


    The International Urogynecological Association (IUGA) and the International Continence Society (ICS) developed a complication classification to facilitate international comparison and to improve our understanding of complications. This code was applied to surgical cases for the analysis of complications after mesh insertion. The study included patients who had undergone vaginal prolapse repair with a trocar-guided polypropylene mesh between 2006 and 2010 in a Dutch peripheral hospital. Complications were assessed at secondary follow-up and classified using category (C), timing (T), and site (S) components (CTS). Of the 107 women included, 84 returned for secondary follow-up (response rate 80 %, median time after surgery 36 months, range 12-64). In 45 patients no complications occurred. In the remaining 39 patients, 43 complication codes were established. Six of the seven categories of complications were found at all different time codes. Concerning the site of the complication codes S1, S2, and S3 were applicable. Perioperative complications (6 %) included hemorrhage and bladder perforation. Six patients were reoperated for symptomatic mesh exposure or local pain. At secondary follow-up exposure was diagnosed in another 4 patients (12 %). In 36 % mesh wrinkling or shrinkage was discovered, although without complaints in most. Eight women had daily complaints or dyspareunia. Eighty-two percent of patients indicated strong improvement after surgery. Several limitations of the classification are discussed. Despite limitations, the IUGA/ICS code is demonstrated to be useful in describing mesh complications. We advise the use of the CTS code at follow-up consultations after a minimum of 2 years for improved insight into and knowledge on the occurrence of complications.

  15. Prevention of parastomal hernias with 3D funnel meshes in intraperitoneal onlay position by placement during initial stoma formation. (United States)

    Köhler, G; Hofmann, A; Lechner, M; Mayer, F; Wundsam, H; Emmanuel, K; Fortelny, R H


    In patients with terminal ostomies, parastomal hernias (PSHs) occur on a frequent basis. They are commonly associated with various degrees of complaints and occasionally lead to life-threatening complications. Various strategies and measures have been tested and evaluated, but to date there is a lack of published evidence with regard to the best surgical technique for the prevention of PSH development. We conducted a retrospective analysis of prospectively collected data of eighty patients, who underwent elective permanent ostomy formation between 2009 and 2014 by means of prophylactic implantation of a three-dimensional (3D) funnel mesh in intraperitoneal onlay (IPOM) position. PSH developed in three patients (3.75%). No mesh-related complications were encountered and none of the implants had to be removed. Ostomy-related complications had to be noted in seven (8.75%) cases. No manifestation of ostomy prolapse occurred. Follow-up time was a median 21 (range 3-47) months. The prophylactical implantation of a specially shaped, 3D mesh implant in IPOM technique during initial formation of a terminal enterostomy is safe, highly efficient and comparatively easy to perform. As opposed to what can be achieved with flat or keyhole meshes, the inner boundary areas of the ostomy itself can be well covered and protected from the surging viscera with the 3D implants. At the same time, the vertical, tunnel-shaped part of the mesh provides sufficient protection from an ostomy prolapse. Further studies will be needed to compare the efficacy of various known approaches to PSH prevention.

  16. Randomized controlled trial of the use of a large-pore polypropylene mesh to prevent incisional hernia in colorectal surgery. (United States)

    García-Ureña, Miguel Ángel; López-Monclús, Javier; Hernando, Luis Alberto Blázquez; Montes, Daniel Melero; Valle de Lersundi, Alvaro Robín; Pavón, Camilo Castellón; Ceinos, Carmen Jiménez; Quindós, Patricia López


    To reduce the incidence of incisional hernia (IH) in colorectal surgery by implanting a mesh on the overlay position. The incidence of IH in colorectal surgery may be as high as 40%. IH causes severe health and cosmetic problems, and its repair increases health care costs. Randomized, controlled, prospective trial. Patients undergoing any colorectal procedure (both elective and emergency) through a midline laparotomy were divided into 2 groups. The abdomen was closed with an identical technique in both groups, except for the implantation of an overlay large-pore polypropylene mesh in the study group. Patients were followed up clinically and radiologically for 24 months. A total of 107 patients were included: 53 in the study group and 54 in the control group. Both groups were homogeneous, except for a higher incidence of diabetes in the mesh group. There were 20 emergency procedures in the study group and 17 in the control group. There were no statistical differences in surgical site infections, seromas, or mortality between the groups (33.3%, 13.8%, and 3.7% in the control group and 18.9%, 13.2%, and 3.8% in the study group). No mesh rejection was reported. The incidence of IH was 17 of 54 (31.5%) in the control group and 6 of 53 (11.3%) in the study group (P = 0.011). The incidence of IH is high in patients undergoing elective or emergency surgery for colorectal diseases. The addition of a prophylactic large-pore polypropylene mesh on the overlay position decreases the incidence of IH without adding morbidity.

  17. Performance of the hybrid wireless mesh protocol for wireless mesh networks

    DEFF Research Database (Denmark)

    Boye, Magnus; Staalhagen, Lars


    . These challenges must first be overcome before satisfactory network stability and throughput can be achieved. This paper studies the performance of the Hybrid Wireless Mesh Protocol, the proposed routing protocol for the upcoming IEEE 802.11s standard. HWMP supports two modes of path selection: reactive...... and proactive. Two scenarios of different node density are considered for both path selection modes. The results presented in this paper are based on a simulation model of the HWMP specification in the IEEE 802.11s draft 4.0 implemented in OPNET Modeler....

  18. Interposition of the omentum and/or the peritoneum in the emergency repair of large ventral hernias with polypropylene mesh. (United States)

    Sorour, Magdy A


    Ventral and incisional hernias are common surgical problems and their repairs are among the common surgeries done by a general surgeon. Repair of a large ventral hernia is still associated with high postoperative morbidity and recurrence rates. No single approach to ventral hernia repair will be the best choice for all patients. Large ventral hernias are often better approached with open surgery but may still be problematic when the defect is too wide for primary fascial closure to be achieved, as this leaves mesh exposed, bridging the gap. Techniques for incisional hernia repair have evolved over many years, and the use of mesh has reduced recurrence rates dramatically. The use of polypropylene mesh is reported to be associated with long-term complications such as severe adhesions and enterocutaneous fistula, which occur more commonly if the mesh is applied intraperitoneally with direct contact of the serosal surface of the intestine. Composite meshes containing expanded polytetrafluoroethylene (ePTFE) have been used recently; their major drawbacks lie in their high cost, inferior handling characteristics, and poor incorporation into the tissues. Although several studies have clearly demonstrated the safety and efficacy of prosthetic mesh repair in the emergency management of the incarcerated and/or strangulated inguinal and ventral hernias, however, surgeons remained reluctant to use prosthetics in such settings. The aim of this work was to evaluate the effectiveness and safety of placing the omentum and/or the peritoneum of the hernia sac as a protective layer over the viscera in the emergency repair of large ventral hernias using on-lay polypropylene mesh whenever complete tension-free closure of the abdominal wall was impossible. This study was carried out on all patients with large ventral hernia presented to the Gastrointestinal Surgery Unit, Main Alexandria University Hospital in an emergency situation during the period from October 2005 till October 2012

  19. The unexplained accuracy of the Lagrange-mesh method

    International Nuclear Information System (INIS)

    Baye, D.; Hesse, M.; Vincke, M.


    The Lagrange-mesh method is an approximate variational calculation which resembles a mesh calculation because of the use of a Gauss quadrature. In order to analyze its accuracy, four different Lagrange-mesh calculations based on the zeros of Laguerre polynomials are compared with exact variational calculations based on the corresponding Laguerre basis. The comparison is performed for three solvable radial potentials: the Morse, harmonic-oscillator, and Coulomb potentials. The results show that the accuracies of the energies obtained for different partial waves with the different mesh approximations are very close to the variational accuracy, even in the presence of the centrifugal singularity. The same property holds for the approximate wave functions. This striking accuracy remains unexplained

  20. Kinetic mesh-free method for flutter prediction in turbomachines

    Indian Academy of Sciences (India)

    -based mesh-free method for unsteady flows. ... Council for Scientific and Industrial Research, National Aerospace Laboratories, Computational and Theoretical Fluid Dynamics Division, Bangalore 560 017, India; Engineering Mechanics Unit, ...

  1. Resistive-force theory for mesh-like superhydrophobic surfaces (United States)

    Schnitzer, Ory; Yariv, Ehud


    A common realization of superhydrophobic surfaces makes use of a mesh-like geometry, where pockets of air are trapped in a periodic array of holes in a no-slip solid substrate. We consider the small-solid-fraction limit where the ribs of the mesh are narrow. In this limit, we obtain a simple leading-order approximation for the slip-length tensor of an arbitrary mesh geometry. This approximation scales as the solid-fraction logarithm, as anticipated by Ybert et al. [Phys. Fluids 19, 123601 (2007), 10.1063/1.2815730]; in the special case of a square mesh it agrees with the analytical results obtained by Davis and Lauga [Phys. Fluids 21, 113101 (2009), 10.1063/1.3250947].

  2. Design and Implementation of the MESH Services Platform

    NARCIS (Netherlands)

    Batteram, Harold J.; Bakker, John-Luc; Verhoosel, Jack P.C.; Diakov, N.K.


    Industry acceptance of TINA (Telecommunications Information Networking Architecture) will depend heavily on both the evaluation of working systems that implement this architecture, and on the experiences obtained during the design and implementation of these systems. During the MESH' (Multimedia

  3. Ordering schemes for parallel processing of certain mesh problems

    International Nuclear Information System (INIS)

    O'Leary, D.


    In this work, some ordering schemes for mesh points are presented which enable algorithms such as the Gauss-Seidel or SOR iteration to be performed efficiently for the nine-point operator finite difference method on computers consisting of a two-dimensional grid of processors. Convergence results are presented for the discretization of u /SUB xx/ + u /SUB yy/ on a uniform mesh over a square, showing that the spectral radius of the iteration for these orderings is no worse than that for the standard row by row ordering of mesh points. Further applications of these mesh point orderings to network problems, more general finite difference operators, and picture processing problems are noted

  4. Metal Mesh Filters for Terahertz Receivers, Phase II (United States)

    National Aeronautics and Space Administration — The technical objective of this SBIR program is to develop and demonstrate metal mesh filters for use in NASA's low noise receivers for terahertz astronomy and...

  5. Application-specific mesh-based heterogeneous FPGA architectures

    CERN Document Server

    Parvez, Husain


    This volume presents a new exploration environment for mesh-based, heterogeneous FPGA architectures. Readers will find a description of state-of-the-art techniques for reducing area requirements, which both increase performance and enable power reduction.

  6. Inductive Cross Shaped Metal Meshes in Silicon Substrate

    National Research Council Canada - National Science Library

    Sternberg, O; Moller, K. D; Grebel, H; Stewart, K. P; Henry, R. M


    .... The Micro-Stripes program was used for the calculation of resonance wavelength and width of resonance of cross shaped metal meshes and best- fit formulas were developed for the presentation of the data...

  7. ARC Code TI: Middleware Using Existing SSH Hosts (Mesh) (United States)

    National Aeronautics and Space Administration — Mesh is a secure, lightweight grid middleware that is based on the addition of a single sign-on capability to the built-in public key authentication mechanism of SSH...

  8. RSW Mixed Element Cell-Centered Medium Mesh (United States)

    National Aeronautics and Space Administration — This RSW gridset is designed as the medium size mixed element grid for use with cell-centered unstructured meshes. UG3 : Grid File Name = rsw_med_mixedcc.b8.ugrid...

  9. Trajectory Optimization Based on Multi-Interval Mesh Refinement Method

    Directory of Open Access Journals (Sweden)

    Ningbo Li


    Full Text Available In order to improve the optimization accuracy and convergence rate for trajectory optimization of the air-to-air missile, a multi-interval mesh refinement Radau pseudospectral method was introduced. This method made the mesh endpoints converge to the practical nonsmooth points and decreased the overall collocation points to improve convergence rate and computational efficiency. The trajectory was divided into four phases according to the working time of engine and handover of midcourse and terminal guidance, and then the optimization model was built. The multi-interval mesh refinement Radau pseudospectral method with different collocation points in each mesh interval was used to solve the trajectory optimization model. Moreover, this method was compared with traditional h method. Simulation results show that this method can decrease the dimensionality of nonlinear programming (NLP problem and therefore improve the efficiency of pseudospectral methods for solving trajectory optimization problems.


    Bajaj, Chandrajit


    We present Laguerre Voronoi based subdivision algorithms for the quadrilateral and hexahedral meshing of particle systems within a bounded region in two and three dimensions, respectively. Particles are smooth functions over circular or spherical domains. The algorithm first breaks the bounded region containing the particles into Voronoi cells that are then subsequently decomposed into an initial quadrilateral or an initial hexahedral scaffold conforming to individual particles. The scaffolds are subsequently refined via applications of recursive subdivision (splitting and averaging rules). Our choice of averaging rules yield a particle conforming quadrilateral/hexahedral mesh, of good quality, along with being smooth and differentiable in the limit. Extensions of the basic scheme to dynamic re-meshing in the case of addition, deletion, and moving particles are also discussed. Motivating applications of the use of these static and dynamic meshes for particle systems include the mechanics of epoxy/glass composite materials, bio-molecular force field calculations, and gas hydrodynamics simulations in cosmology.

  11. Form-finding with polyhedral meshes made simple

    KAUST Repository

    Tang, Chengcheng


    We solve the form-finding problem for polyhedral meshes in a way which combines form, function and fabrication; taking care of user-specified constraints like boundary interpolation, planarity of faces, statics, panel size and shape, enclosed volume, and last, but not least, cost. Our main application is the interactive modeling of meshes for architectural and industrial design. Our approach can be described as guided exploration of the constraint space whose algebraic structure is simplified by introducing auxiliary variables and ensuring that constraints are at most quadratic. Computationally, we perform a projection onto the constraint space which is biased towards low values of an energy which expresses desirable "soft" properties like fairness. We have created a tool which elegantly handles difficult tasks, such as taking boundary-alignment of polyhedral meshes into account, planarization, fairing under planarity side conditions, handling hybrid meshes, and extending the treatment of static equilibrium to shapes which possess overhanging parts.

  12. High Order Mesh Curving and Geometry Access, Phase I (United States)

    National Aeronautics and Space Administration — During Phase I, our effort will focus on three software tools; CurveMesh, Geode and SLUGS. These tools will be developed in anticipation of use in the commercial...

  13. Dielectrically embedded flat mesh lens for millimeter waves applications. (United States)

    Pisano, Giampaolo; Ng, Ming Wah; Ozturk, Fahri; Maffei, Bruno; Haynes, Vic


    A flat lens based on subwavelength periodic metal meshes has been developed using photolithographic techniques. These mesh grids are stacked at specific distances and embedded in polypropylene. A code was developed to optimize more than 1000 transmission line circuits required to vary the device phase shift across the lens flat surface, mimicking the behavior of a classical lens. A W-band mesh-lens prototype was successfully manufactured and its RF performance characterized using a vector network analyzer coupled to corrugated horn antennas. Co-polarization far-field beam patterns were measured and compared with finite-element method models. The excellent agreement between data and simulations validated our designing tools and manufacturing procedures. This mesh lens is a low-loss, robust, light, and compact device that has many potential applications including millimeter wave quasi-optical systems for future cosmic microwave background polarization instruments.

  14. Reconstruction of an abdominal wall defect with biologic mesh after resection of a desmoid tumor in a patient with a Gardner's syndrome. (United States)

    Hammer, Jennifer; Léonard, Daniel; Chateau, François; Abbes Orabi, Nora; Ciccarelli, Olga; Bachmann, Radu; Remue, Christophe; Lengelé, Benoît; Kartheuser, Alex


    Desmoid tumors are rare proliferative and invasive benign lesions. They can be sporadic, but in most instances, desmoid tumors develop in the context of Gardner's syndrome with principal localization in the abdominal cavity and abdominal wall. We report the case of a 24-year-old female presenting Gardner's syndrome with a symptomatic abdominal wall desmoid tumor. Lack of response to medical treatment led to surgical management consisting in a complete resection and parietal reconstruction with a biologic mesh. Postoperative course was uneventful and there was no evidence of recurrence at 12 months of follow-up. Conventional treatment of abdominal wall desmoid tumors consists in a wide and radical resection. However, complete resection is not always feasible because of difficulty to differentiate the desmoid tumor from adjacent tissues. The surgical approach may require different techniques to repair the parietal defect including prosthetic material such as synthetic or biologic meshes. Biological mesh is an ideal alternative to synthetic graft, mainly in case of infection. We have encountered a case of a symptomatic growing desmoid tumor of the abdominal wall in a young patient with Gardner's syndrome, successfully treated by complete resection and reconstruction with a biologic mesh to correct the parietal defect.

  15. Finite element meshing approached as a global minimization process

    Energy Technology Data Exchange (ETDEWEB)



    The ability to generate a suitable finite element mesh in an automatic fashion is becoming the key to being able to automate the entire engineering analysis process. However, placing an all-hexahedron mesh in a general three-dimensional body continues to be an elusive goal. The approach investigated in this research is fundamentally different from any other that is known of by the authors. A physical analogy viewpoint is used to formulate the actual meshing problem which constructs a global mathematical description of the problem. The analogy used was that of minimizing the electrical potential of a system charged particles within a charged domain. The particles in the presented analogy represent duals to mesh elements (i.e., quads or hexes). Particle movement is governed by a mathematical functional which accounts for inter-particles repulsive, attractive and alignment forces. This functional is minimized to find the optimal location and orientation of each particle. After the particles are connected a mesh can be easily resolved. The mathematical description for this problem is as easy to formulate in three-dimensions as it is in two- or one-dimensions. The meshing algorithm was developed within CoMeT. It can solve the two-dimensional meshing problem for convex and concave geometries in a purely automated fashion. Investigation of the robustness of the technique has shown a success rate of approximately 99% for the two-dimensional geometries tested. Run times to mesh a 100 element complex geometry were typically in the 10 minute range. Efficiency of the technique is still an issue that needs to be addressed. Performance is an issue that is critical for most engineers generating meshes. It was not for this project. The primary focus of this work was to investigate and evaluate a meshing algorithm/philosophy with efficiency issues being secondary. The algorithm was also extended to mesh three-dimensional geometries. Unfortunately, only simple geometries were tested

  16. Abortion - surgical - aftercare (United States)

    ... this page: // Abortion - surgical - aftercare To use the sharing features on ... please enable JavaScript. You have had a surgical abortion. This is a procedure that ends pregnancy by ...

  17. Optimizing surgical f

    Directory of Open Access Journals (Sweden)

    Sabry Mohamed Amin


    Conclusions: In our study both dexmedetomidine and esmolol were effective in reducing MABP, and lowering the heart rate providing dry surgical field and ensured good surgical condition during cochlear implant surgery in pediatric patients.

  18. American Pediatric Surgical Association (United States)

    American Pediatric Surgical Association Search for: Login Resources + For Members For Professionals For Training Program Directors For Media For ... Surgical Outcomes Surveys & Results Publications Continuing Education + ExPERT Pediatric Surgery NaT Annual Meeting CME MOC Requirements Residents / ...

  19. Poly(ε-caprolactone) Microfiber Meshes for Repeated Oil Retrieval


    Hersey, J. S.; Yohe, S. T.; Grinstaff, M. W.


    Electrospun non-woven poly(ε-caprolactone) (PCL) microfiber meshes are described as biodegradable, mechanically robust, and reusable polymeric oil sorbents capable of selectively retrieving oil from simulated oil spills in both fresh and seawater scenarios. Hydrophobic PCL meshes have >99.5% (oil over water) oil selectivity and oil absorption capacities of ~10 grams of oil per gram of sorbent material, which is shown to be a volumetrically driven process. Both the oil selectivity and absorpti...

  20. Parallel adaptive mesh refinement for electronic structure calculations

    Energy Technology Data Exchange (ETDEWEB)

    Kohn, S.; Weare, J.; Ong, E.; Baden, S.


    We have applied structured adaptive mesh refinement techniques to the solution of the LDA equations for electronic structure calculations. Local spatial refinement concentrates memory resources and numerical effort where it is most needed, near the atomic centers and in regions of rapidly varying charge density. The structured grid representation enables us to employ efficient iterative solver techniques such as conjugate gradients with multigrid preconditioning. We have parallelized our solver using an object-oriented adaptive mesh refinement framework.

  1. Two-dimensional isostatic meshes in the finite element method


    Martínez Marín, Rubén; Samartín, Avelino


    In a Finite Element (FE) analysis of elastic solids several items are usually considered, namely, type and shape of the elements, number of nodes per element, node positions, FE mesh, total number of degrees of freedom (dot) among others. In this paper a method to improve a given FE mesh used for a particular analysis is described. For the improvement criterion different objective functions have been chosen (Total potential energy and Average quadratic error) and the number of nodes and dof's...

  2. Overlap Areas of a Square Box on a Square Mesh (United States)


    ABSTRACT To aid in a data-reduction process, an algorithm was generated to calculate on a square mesh (elements with sides of length 2m) the area of... aid in a data-reduction process, an algorithm was generated to calculate on a square mesh (elements with sides of length 2m) the area of overlap official Department of the Army position unless so designated by other authorized documents. Citation of manufacturer’s or trade names does not

  3. Enhancing physiologic simulations using supervised learning on coarse mesh solutions. (United States)

    Kolandaivelu, Kumaran; O'Brien, Caroline C; Shazly, Tarek; Edelman, Elazer R; Kolachalama, Vijaya B


    Computational modelling of physical and biochemical processes has emerged as a means of evaluating medical devices, offering new insights that explain current performance, inform future designs and even enable personalized use. Yet resource limitations force one to compromise with reduced order computational models and idealized assumptions that yield either qualitative descriptions or approximate, quantitative solutions to problems of interest. Considering endovascular drug delivery as an exemplary scenario, we used a supervised machine learning framework to process data generated from low fidelity coarse meshes and predict high fidelity solutions on refined mesh configurations. We considered two models simulating drug delivery to the arterial wall: (i) two-dimensional drug-coated balloons and (ii) three-dimensional drug-eluting stents. Simulations were performed on computational mesh configurations of increasing density. Supervised learners based on Gaussian process modelling were constructed from combinations of coarse mesh setting solutions of drug concentrations and nearest neighbourhood distance information as inputs, and higher fidelity mesh solutions as outputs. These learners were then used as computationally inexpensive surrogates to extend predictions using low fidelity information to higher levels of mesh refinement. The cross-validated, supervised learner-based predictions improved fidelity as compared with computational simulations performed at coarse level meshes--a result consistent across all outputs and computational models considered. Supervised learning on coarse mesh solutions can augment traditional physics-based modelling of complex physiologic phenomena. By obtaining efficient solutions at a fraction of the computational cost, this framework has the potential to transform how modelling approaches can be applied in the evaluation of medical technologies and their real-time administration in an increasingly personalized fashion.

  4. Fibrin sealant for mesh fixation in laparoscopic umbilical hernia repair

    DEFF Research Database (Denmark)

    Eriksen, J R; Bisgaard, T; Assaadzadeh, S


    Fibrin sealant for mesh fixation has significant positive effects on early outcome after laparoscopic ventral hernia repair (LVHR) compared with titanium tacks. Whether fibrin sealant fixation also results in better long-term outcome is unknown.......Fibrin sealant for mesh fixation has significant positive effects on early outcome after laparoscopic ventral hernia repair (LVHR) compared with titanium tacks. Whether fibrin sealant fixation also results in better long-term outcome is unknown....

  5. Mesh Generation via Local Bisection Refinement of Triangulated Grids (United States)


    Science and Technology Organisation DSTO–TR–3095 ABSTRACT This report provides a comprehensive implementation of an unstructured mesh generation method...and Technology Organisation 506 Lorimer St, Fishermans Bend, Victoria 3207, Australia Telephone: 1300 333 362 Facsimile: (03) 9626 7999 c© Commonwealth...their behaviour is critically linked to Maubach’s method and the data structures N and T . The top- level mesh refinement algorithm is also presented

  6. Incisional hernia prevention using a cyanoacrilate-fixed retrofascial mesh. (United States)

    Hoyuela, Carlos; Juvany, Montserrat; Trias, Miquel; Ardid, Jordi; Martrat, Antoni


    The rate of incisional hernia in high-risk patients (obesity, cancer, etc.) is high, even in laparoscopic surgery. The aim of this study is to evaluate the safety of the use of cyanoacrylate fixed prophylactic meshes in the assistance incision in overweight or obese patients undergoing laparoscopic colorectal surgery. A prospective, non-randomized cohort study of patients undergoing elective laparoscopic resection for colorectal cancer between January 2013 and March 2016 was performed. Those with a body mass index greater than 25kg / m 2 were evaluated to implant a prophylactic meshes fixed with cyanoacrylate (Histoacryl®) as reinforcement of the assistance incision. 52 patients were analyzed (mean body mass index: 28.4±2kg / m 2 ). Prophylactic meshes was implanted in 15 patients. The time to put the mesh in place was always less than 5minutes. There was no significant difference in wound infection rate (12% vs. 10%). No mesh had to be explanted. Although the mean follow-up was shorter (14.1±4 vs. 22.3±9 months), there were no incisional hernia in the mesh group. On the other hand, in the non-mesh group, 1 acute evisceration (2.7%) and 4 incisional hernia of the assistance incision were observed (10.8%). There were no significant differences between groups regarding trocar incisional hernia (6.6 vs. 5.4%). The implantation of a reinforcement prophylactic mesh in overweight or obese patients undergoing laparoscopic colorectal surgery is safe and seems to reduce the short-term rate of incisional hernia. Fixation with cyanoacrylate is a rapid method that facilitates the procedure without additional complications. Copyright © 2017 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

  7. Materials characterization of explanted polypropylene hernia mesh: Patient factor correlation. (United States)

    Smith, Sarah E; Cozad, Matthew J; Grant, David A; Ramshaw, Bruce J; Grant, Sheila A


    This study quantitatively assessed polypropylene (PP) hernia mesh degradation and its correlation with patient factors including body mass index, tobacco use, and diabetes status with the goal of improving hernia repair outcomes through patient-matched mesh. Thirty PP hernia mesh explants were subjected to a tissue removal process followed by assessment of their in vivo degradation using Fourier transform infrared, differential scanning calorimetry, and thermogravimetric analysis analyses. Results were then analyzed with respect to patient factors (body mass index, tobacco use, and diabetes status) to determine their influence on in vivo hernia mesh oxidation and degradation. Twenty of the explants show significant surface oxidation. Tobacco use exhibits a positive correlation with modulated differential scanning calorimetry melt temperature and exhibits significantly lower TGA decomposition temperatures than non-/past users. Chemical and thermal characterization of the explanted meshes indicate measurable degradation while in vivo regardless of the patient population; however, tobacco use is correlated with less oxidation and degradation of the polymeric mesh possibly due to a reduced inflammatory response. © The Author(s) 2015.

  8. Thermal Analysis of Concrete Storage Cask with Bird Screen Meshes

    International Nuclear Information System (INIS)

    Lee, Ju-Chan; Bang, K.S.; Yu, S.H.; Cho, S.S.; Choi, W.S.


    In this study, a thermal analysis of the cask with bird screen meshes has been performed using a porous media model. The overpack consists of a structural material, a concrete shielding, and a ventilation system. Heat is removed from the cask to the environment by a passive means only. Air inlet and outlet ducts are installed at the bottom and top of the cask for a ventilation system. Bird screen meshes are installed at the air inlet and outlet ducts to inhibit intrusion of debris from the external environment. The presence of this screens introduce an additional resistance to air flow through the ducts. Five types of meshes for bird screen were considered in this study. The bird screen meshes at the inlet and outlet vents reduce the open area for flow by about 44 - 79 %. Flow resistance coefficients for porous media model were deduced from the fluid flow analysis of bird screen meshes. Thermal analyses for the concrete cask have been carried out using a porous media model. The analysis results agreed well with the test results. Therefore, it was shown that the porous media model for the screen mesh was established to estimate the cask temperatures

  9. An Implementation and Parallelization of the Scale Space Meshing Algorithm

    Directory of Open Access Journals (Sweden)

    Julie Digne


    Full Text Available Creating an interpolating mesh from an unorganized set of oriented points is a difficult problemwhich is often overlooked. Most methods focus indeed on building a watertight smoothed meshby defining some function whose zero level set is the surface of the object. However in some casesit is crucial to build a mesh that interpolates the points and does not fill the acquisition holes:either because the data are sparse and trying to fill the holes would create spurious artifactsor because the goal is to explore visually the data exactly as they were acquired without anysmoothing process. In this paper we detail a parallel implementation of the Scale-Space Meshingalgorithm, which builds on the scale-space framework for reconstructing a high precision meshfrom an input oriented point set. This algorithm first smoothes the point set, producing asingularity free shape. It then uses a standard mesh reconstruction technique, the Ball PivotingAlgorithm, to build a mesh from the smoothed point set. The final step consists in back-projecting the mesh built on the smoothed positions onto the original point set. The result ofthis process is an interpolating, hole-preserving surface mesh reconstruction.

  10. Adaptive mesh refinement for shocks and material interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Dai, William Wenlong [Los Alamos National Laboratory


    There are three kinds of adaptive mesh refinement (AMR) in structured meshes. Block-based AMR sometimes over refines meshes. Cell-based AMR treats cells cell by cell and thus loses the advantage of the nature of structured meshes. Patch-based AMR is intended to combine advantages of block- and cell-based AMR, i.e., the nature of structured meshes and sharp regions of refinement. But, patch-based AMR has its own difficulties. For example, patch-based AMR typically cannot preserve symmetries of physics problems. In this paper, we will present an approach for a patch-based AMR for hydrodynamics simulations. The approach consists of clustering, symmetry preserving, mesh continuity, flux correction, communications, management of patches, and load balance. The special features of this patch-based AMR include symmetry preserving, efficiency of refinement across shock fronts and material interfaces, special implementation of flux correction, and patch management in parallel computing environments. To demonstrate the capability of the AMR framework, we will show both two- and three-dimensional hydrodynamics simulations with many levels of refinement.

  11. The quasidiffusion method for transport problems on unstructured meshes (United States)

    Wieselquist, William A.


    In this work, we develop a quasidiffusion (QD) method for solving radiation transport problems on unstructured quadrilateral meshes in 2D Cartesian geometry, for example hanging-node meshes from adaptive mesh refinement (AMR) applications or skewed quadrilateral meshes from radiation hydrodynamics with Lagrangian meshing. The main result of the work is a new low-order quasidiffusion (LOQD) discretization on arbitrary quadrilaterals and a strategy for the efficient iterative solution which uses Krylov methods and incomplete LU factorization (ILU) preconditioning. The LOQD equations are a non-symmetric set of first-order PDEs that in second-order form resembles convection- diffusion with a diffusion tensor, with the difference that the LOQD equations contain extra cross-derivative terms. Our finite volume (FV) discretization of the LOQD equations is compared with three LOQD discretizations from literature. We then present a conservative, short characteristics discretization based on subcell balances (SCSB) that uses polynomial exponential moments to achieve robust behavior in various limits (e.g. small cells and voids) and is second- order accurate in space. A linear representation of the isotropic component of the scattering source based on face-average and cell-average scalar fluxes is also proposed and shown to be effective in some problems. In numerical tests, our QD method with linear scattering source representation shows some advantages compared to other transport methods. We conclude with avenues for future research and note that this QD method may easily be extended to arbitrary meshes in 3D Cartesian geometry.

  12. Adaptive soft tissue deformation for a virtual reality surgical trainer. (United States)

    Jerabkova, Lenka; Wolter, Timm P; Pallua, Norbert; Kuhlen, Torsten


    Real time tissue deformation is an important aspect of interactive virtual reality (VR) environments such as medical trainers. Most approaches in deformable modelling use a fixed space discretization. A surgical trainer requires high plausibility of the deformations especially in the area close to the instrument. As the area of intervention is not known a priori, adaptive techniques have to be applied. We present an approach for real time deformation of soft tissue based on a regular FEM mesh of cube elements as opposed to a mesh of tetrahedral elements used by the majority of soft tissue simulators. A regular mesh structure simplifies the local refinement operation as the elements topology and stiffness are known implicitly. We propose an octree-based adaptive multiresolution extension of our basic approach. The volumetric representation of the deformed object is created automatically from medical images or by voxelization of a surface model. The resolution of the volumetric representation is independent of the surface geometry resolution. The surface is deformed according to the simulation performed on the underlying volumetric mesh.

  13. Magnetic resonance imaging of abdominal versus vaginal prolapse surgery with mesh. (United States)

    Ginath, Shimon; Garely, Alan D; Luchs, Jonathan S; Shahryarinejad, Azin; Olivera, Cedric K; Zhou, Sue; Ascher-Walsh, Charles J; Condrea, Alexander; Brodman, Michael L; Vardy, Michael D


    We compared two surgical approaches in patients with symptomatic prolapse of the vaginal apex with normal controls by analyzing pelvic landmark relationships measured using magnetic resonance imaging (MRI) before and after surgery. In this prospective multicenter pilot study involving 16 participants, nulliparous controls (n = 6) were compared with ten parous (3.0 ± 1.0) women with uterine apical prolapse equal to or greater than stage 2. Group A (n = 5) underwent abdominal sacral colpopexy with monofilament polypropylene mesh and group B (n = 5) with vaginal mesh kit repair (Total ProLift). Subtotal hysterectomy was performed in all group A and no group B women. All patients underwent preoperative and 3-month postoperative Pelvic Organ Prolapse Quantification (POP-Q) and dynamic MRI. Comparison of MRI pelvic angles and distances was performed and analyzed by Mann-Whitney rank sum test and chi-square test. Vaginal apical support is similar at 3 months for abdominal sacral colpopexy (ASCP) and ProLift by POP-Q examination and MRI analysis. In both treatment groups, the postoperative POP-Q point C and MRI parameters were similar to nulliparous controls at 3 months. Anatomic outcomes for ASCP compared with ProLift were similar at 3 months in terms of vaginal apical support by POP-Q and MRI analysis. Continued comparative analysis of postoperative support with objective imaging seems warranted.

  14. Combined in vivo and ex vivo analysis of mesh mechanics in a porcine hernia model. (United States)

    Kahan, Lindsey G; Lake, Spencer P; McAllister, Jared M; Tan, Wen Hui; Yu, Jennifer; Thompson, Dominic; Brunt, L Michael; Blatnik, Jeffrey A


    Hernia meshes exhibit variability in mechanical properties, and their mechanical match to tissue has not been comprehensively studied. We used an innovative imaging model of in vivo strain tracking and ex vivo mechanical analysis to assess effects of mesh properties on repaired abdominal walls in a porcine model. We hypothesized that meshes with dissimilar mechanical properties compared to native tissue would alter abdominal wall mechanics more than better-matched meshes. Seven mini-pigs underwent ventral hernia creation and subsequent open repair with one of two heavyweight polypropylene meshes. Following mesh implantation with attached radio-opaque beads, fluoroscopic images were taken at insufflation pressures from 5 to 30 mmHg on postoperative days 0, 7, and 28. At 28 days, animals were euthanized and ex vivo mechanical testing performed on full-thickness samples across repaired abdominal walls. Testing was conducted on 13 mini-pig controls, and on meshes separately. Stiffness and anisotropy (the ratio of stiffness in the transverse versus craniocaudal directions) were assessed. 3D reconstructions of repaired abdominal walls showed stretch patterns. As pressure increased, both meshes expanded, with no differences between groups. Over time, meshes contracted 17.65% (Mesh A) and 0.12% (Mesh B; p = 0.06). Mesh mechanics showed that Mesh A deviated from anisotropic native tissue more than Mesh B. Compared to native tissue, Mesh A was stiffer both transversely and craniocaudally. Explanted repaired abdominal walls of both treatment groups were stiffer than native tissue. Repaired tissue became less anisotropic over time, as mesh properties prevailed over native abdominal wall properties. This technique assessed 3D stretch at the mesh level in vivo in a porcine model. While the abdominal wall expanded, mesh-ingrown areas contracted, potentially indicating stresses at mesh edges. Ex vivo mechanics demonstrate that repaired tissue adopts mesh properties, suggesting

  15. The Analysis of the Usefulness of Welded Meshes to Embankment Reinforcement (United States)

    Ćwirko, Marcin; Jastrzębska, Małgorzata; Kwiecień, Sławomir


    The aim of this paper was to find an answer to the question about the possibility of using steel welded mesh in building the retaining walls of gabion baskets. In light of the currently used gabion structure solutions, among which double-woven mesh is much more popular, the focus was put on the possibility of using welded mesh. A numerical analysis was conducted to examine the behavior of welded and woven mesh subjected to various loads and the results obtained for both types of mesh were directly compared. The maximal displacement in mesh nodes was admitted as the measurement of the system behavior (in the case of both undamaged and damaged mesh).

  16. Anisotropic mesh adaptation for marine ice-sheet modelling (United States)

    Gillet-Chaulet, Fabien; Tavard, Laure; Merino, Nacho; Peyaud, Vincent; Brondex, Julien; Durand, Gael; Gagliardini, Olivier


    Improving forecasts of ice-sheets contribution to sea-level rise requires, amongst others, to correctly model the dynamics of the grounding line (GL), i.e. the line where the ice detaches from its underlying bed and goes afloat on the ocean. Many numerical studies, including the intercomparison exercises MISMIP and MISMIP3D, have shown that grid refinement in the GL vicinity is a key component to obtain reliable results. Improving model accuracy while maintaining the computational cost affordable has then been an important target for the development of marine icesheet models. Adaptive mesh refinement (AMR) is a method where the accuracy of the solution is controlled by spatially adapting the mesh size. It has become popular in models using the finite element method as they naturally deal with unstructured meshes, but block-structured AMR has also been successfully applied to model GL dynamics. The main difficulty with AMR is to find efficient and reliable estimators of the numerical error to control the mesh size. Here, we use the estimator proposed by Frey and Alauzet (2015). Based on the interpolation error, it has been found effective in practice to control the numerical error, and has some flexibility, such as its ability to combine metrics for different variables, that makes it attractive. Routines to compute the anisotropic metric defining the mesh size have been implemented in the finite element ice flow model Elmer/Ice (Gagliardini et al., 2013). The mesh adaptation is performed using the freely available library MMG (Dapogny et al., 2014) called from Elmer/Ice. Using a setup based on the inter-comparison exercise MISMIP+ (Asay-Davis et al., 2016), we study the accuracy of the solution when the mesh is adapted using various variables (ice thickness, velocity, basal drag, …). We show that combining these variables allows to reduce the number of mesh nodes by more than one order of magnitude, for the same numerical accuracy, when compared to uniform mesh

  17. MeSH ORA framework: R/Bioconductor packages to support MeSH over-representation analysis. (United States)

    Tsuyuzaki, Koki; Morota, Gota; Ishii, Manabu; Nakazato, Takeru; Miyazaki, Satoru; Nikaido, Itoshi


    In genome-wide studies, over-representation analysis (ORA) against a set of genes is an essential step for biological interpretation. Many gene annotation resources and software platforms for ORA have been proposed. Recently, Medical Subject Headings (MeSH) terms, which are annotations of PubMed documents, have been used for ORA. MeSH enables the extraction of broader meaning from the gene lists and is expected to become an exhaustive annotation resource for ORA. However, the existing MeSH ORA software platforms are still not sufficient for several reasons. In this work, we developed an original MeSH ORA framework composed of six types of R packages, including MeSH.db, MeSH.AOR.db, MeSH.PCR.db, the org.MeSH.XXX.db-type packages, MeSHDbi, and meshr. Using our framework, users can easily conduct MeSH ORA. By utilizing the enriched MeSH terms, related PubMed documents can be retrieved and saved on local machines within this framework.

  18. Repair of recurrent hernia after biologic mesh failure in abdominal wall reconstruction. (United States)

    Purnell, Chad A; Souza, Jason M; Park, Eugene; Dumanian, Gregory A


    Biologic mesh is commonly used in abdominal wall reconstruction but may result in increased hernia recurrence. There are minimal data on repair of these recurrent hernias. We conducted a retrospective chart review of 24 patients presenting to a single surgeon with recurrent ventral hernia, previously repaired with biologic mesh. Seventeen of 24 study patients underwent open repair, including 5 revisions of incomplete external oblique release. Mesh was polypropylene in 11 patients and fenestrated condensed polytetrafluoroethylene in 3 patients. In 1 patient, no mesh was used. In 2 patients, bridged biologic mesh was used because of risk of exposure. All biologic repairs have since recurred. Complications occurred in 3 of 15 prosthetic mesh patients and in all biologic mesh patients. Prior components release can be repeated if computed tomography scan reveals incomplete release. Recurrence is common after bridged biologic mesh repair. Conventional mesh can be used safely in many recurrent abdominal hernias after biologic mesh failure. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. A Rare Complication of Composite Dual Mesh: Migration and Enterocutaneous Fistula Formation

    Directory of Open Access Journals (Sweden)

    Ozgur Bostanci


    Full Text Available Introduction. Mesh is commonly employed for abdominal hernia repair because it ensures a low recurrence rate. However, enterocutaneous fistula due to mesh migration can occur as a very rare, late complication, for which diagnosis is very difficult. Presentation of Case. Here we report the case of an enterocutaneous fistula due to late mesh migration in a mentally retarded, diabetic, 35-year-old male after umbilical hernia repair with composite dual mesh in 2010. Discussion. Mesh is a foreign substance, because of that some of the complications including hematoma, seroma, foreign body reaction, organ damage, infection, mesh rejection, and fistula formation may occur after implantation of the mesh. In the literature, most cases of mesh-associated enterocutaneous fistula due to migration involved polypropylene meshes. Conclusion. This case serves as a reminder of migration of composite dual meshes.

  20. Effect of Mesh Distribution on Impact Resistance Performance of Kenaf Fibre Reinforced Concrete (United States)

    Che Muda, Zakaria; Thiruchelvam, Sivadass; Syamsir, Agusril; Sheng, Chiam Yung; Beddu, Salmia; Nasharuddin Mustapha, Kamal; Usman, Fathoni; Liyana Mohd Kamal, Nur; Ashraful Alam, Md; Birima, Ahmed H.; Zaroog, O. S.


    This paper investigate the effect of the mesh distribution on the impact performance of kenaf fibre mesh reinforced concrete (KFMRC) for the concrete slab of 300mm × 300mm size reinforced with varied thickness and mesh diameter subjected to low impact projectile test. A self-fabricated drop-weight impact test rig with a steel ball weight of 1.236 kg drop at 0.40 m height has been used in this research work. The objective of this research is to study the effect of the mesh distribution on the impact resistance kenaf fibre mesh concrete for various slab thickness and mesh diameter. 2-layers one Top and one Bottom mesh distribution kenaf mesh is the most efficient in the ability to control crack formation and propagation against impact energy followed by 1-layer Middle mesh distribution and lastly the 1-layer Top mesh distribution is the least effective.

  1. Toward the Development of Virtual Surgical Tools to Aid Orthopaedic FE Analyses

    Directory of Open Access Journals (Sweden)

    Srinivas C. Tadepalli


    Full Text Available Computational models of joint anatomy and function provide a means for biomechanists, physicians, and physical therapists to understand the effects of repetitive motion, acute injury, and degenerative diseases. Finite element models, for example, may be used to predict the outcome of a surgical intervention or to improve the design of prosthetic implants. Countless models have been developed over the years to address a myriad of orthopaedic procedures. Unfortunately, few studies have incorporated patient-specific models. Historically, baseline anatomic models have been used due to the demands associated with model development. Moreover, surgical simulations impose additional modeling challenges. Current meshing practices do not readily accommodate the inclusion of implants. Our goal is to develop a suite of tools (virtual instruments and guides which enable surgical procedures to be readily simulated and to facilitate the development of all-hexahedral finite element mesh definitions.

  2. 3D face analysis by using Mesh-LBP feature (United States)

    Wang, Haoyu; Yang, Fumeng; Zhang, Yuming; Wu, Congzhong


    Objective: Face Recognition is one of the widely application of image processing. Corresponding two-dimensional limitations, such as the pose and illumination changes, to a certain extent restricted its accurate rate and further development. How to overcome the pose and illumination changes and the effects of self-occlusion is the research hotspot and difficulty, also attracting more and more domestic and foreign experts and scholars to study it. 3D face recognition fusing shape and texture descriptors has become a very promising research direction. Method: Our paper presents a 3D point cloud based on mesh local binary pattern grid (Mesh-LBP), then feature extraction for 3D face recognition by fusing shape and texture descriptors. 3D Mesh-LBP not only retains the integrity of the 3D geometry, is also reduces the need for recognition process of normalization steps, because the triangle Mesh-LBP descriptor is calculated on 3D grid. On the other hand, in view of multi-modal consistency in face recognition advantage, construction of LBP can fusing shape and texture information on Triangular Mesh. In this paper, some of the operators used to extract Mesh-LBP, Such as the normal vectors of the triangle each face and vertex, the gaussian curvature, the mean curvature, laplace operator and so on. Conclusion: First, Kinect devices obtain 3D point cloud face, after the pretreatment and normalization, then transform it into triangular grid, grid local binary pattern feature extraction from face key significant parts of face. For each local face, calculate its Mesh-LBP feature with Gaussian curvature, mean curvature laplace operator and so on. Experiments on the our research database, change the method is robust and high recognition accuracy.

  3. Hierarchical multi-resolution mesh networks for brain decoding. (United States)

    Onal Ertugrul, Itir; Ozay, Mete; Yarman Vural, Fatos T


    Human brain is supposed to process information in multiple frequency bands. Therefore, we can extract diverse information from functional Magnetic Resonance Imaging (fMRI) data by processing it at multiple resolutions. We propose a framework, called Hierarchical Multi-resolution Mesh Networks (HMMNs), which establishes a set of brain networks at multiple resolutions of fMRI signal to represent the underlying cognitive process. Our framework, first, decomposes the fMRI signal into various frequency subbands using wavelet transform. Then, a brain network is formed at each subband by ensembling a set of local meshes. Arc weights of each local mesh are estimated by ridge regression. Finally, adjacency matrices of mesh networks obtained at different subbands are used to train classifiers in an ensemble learning architecture, called fuzzy stacked generalization (FSG). Our decoding performances on Human Connectome Project task-fMRI dataset reflect that HMMNs can successfully discriminate tasks with 99% accuracy, across 808 subjects. Diversity of information embedded in mesh networks of multiple subbands enables the ensemble of classifiers to collaborate with each other for brain decoding. The suggested HMMNs decode the cognitive tasks better than a single classifier applied to any subband. Also mesh networks have a better representation power compared to pairwise correlations or average voxel time series. Moreover, fusion of diverse information using FSG outperforms fusion with majority voting. We conclude that, fMRI data, recorded during a cognitive task, provide diverse information in multi-resolution mesh networks. Our framework fuses this complementary information and boosts the brain decoding performances obtained at individual subbands.

  4. PLUM: Parallel Load Balancing for Unstructured Adaptive Meshes (United States)

    Oliker, Leonid


    Dynamic mesh adaption on unstructured grids is a powerful tool for computing large-scale problems that require grid modifications to efficiently resolve solution features. Unfortunately, an efficient parallel implementation is difficult to achieve, primarily due to the load imbalance created by the dynamically-changing nonuniform grid. To address this problem, we have developed PLUM, an automatic portable framework for performing adaptive large-scale numerical computations in a message-passing environment. First, we present an efficient parallel implementation of a tetrahedral mesh adaption scheme. Extremely promising parallel performance is achieved for various refinement and coarsening strategies on a realistic-sized domain. Next we describe PLUM, a novel method for dynamically balancing the processor workloads in adaptive grid computations. This research includes interfacing the parallel mesh adaption procedure based on actual flow solutions to a data remapping module, and incorporating an efficient parallel mesh repartitioner. A significant runtime improvement is achieved by observing that data movement for a refinement step should be performed after the edge-marking phase but before the actual subdivision. We also present optimal and heuristic remapping cost metrics that can accurately predict the total overhead for data redistribution. Several experiments are performed to verify the effectiveness of PLUM on sequences of dynamically adapted unstructured grids. Portability is demonstrated by presenting results on the two vastly different architectures of the SP2 and the Origin2OOO. Additionally, we evaluate the performance of five state-of-the-art partitioning algorithms that can be used within PLUM. It is shown that for certain classes of unsteady adaption, globally repartitioning the computational mesh produces higher quality results than diffusive repartitioning schemes. We also demonstrate that a coarse starting mesh produces high quality load balancing, at

  5. Altering surface characteristics of polypropylene mesh via sodium hydroxide treatment. (United States)

    Regis, Shawn; Jassal, Manisha; Mukherjee, Nilay; Bayon, Yves; Scarborough, Nelson; Bhowmick, Sankha


    Incisional hernias represent a serious and common complication following laparotomy. The use of synthetic (e.g. polypropylene) meshes to aid repair of these hernias has considerably reduced recurrence rates. While polypropylene is biocompatible and has a long successful clinical history in treating hernias and preventing reherniation, this material may suffer some limitations, particularly in challenging patients at risk of wound failure due to, for example, an exaggerated inflammation reaction, delayed wound healing, and infection. Surface modification of the polypropylene mesh without sacrificing its mechanical properties, critical for hernia repair, represents one way to begin to address these clinical complications. Our hypothesis is treatment of a proprietary polypropylene mesh with sodium hydroxide (NaOH) will increase in vitro NIH/3T3 cell attachment, predictive of earlier and improved cell colonization and tissue integration of polypropylene materials. Our goal is to achieve this altered surface functionality via enhanced removal of chemicals/oils used during material synthesis without compromising the mechanical properties of the mesh. We found that NaOH treatment does not appear to compromise the mechanical strength of the material, despite roughly a 10% decrease in fiber diameter. The treatment increases in vitro NIH/3T3 cell attachment within the first 72 h and this effect is sustained up to 7 days in vitro. This research demonstrates that sodium hydroxide treatment is an efficient way to modify the surface of polypropylene hernia meshes without losing the mechanical integrity of the material. This simple procedure could also allow the attachment of a variety of biomolecules to the polypropylene mesh that may aid in reducing the complications associated with polypropylene meshes today. Copyright © 2012 Wiley Periodicals, Inc.

  6. Surgical management of the radiated chest wall

    International Nuclear Information System (INIS)

    Arnold, P.G.; Pairolero, P.C.


    Fifty consecutive patients with radiation-related problems of the chest wall were treated between 1976 and 1984. There were 40 women and 10 men with an average age of 54 years (range 26 to 78 years). Twenty-three patients had radiation ulcers alone, 20 had recurrent cancer, and 7 had infected median sternotomy wounds. Thirty-six had skeletal resections and 44 had soft-tissue resections. The skeleton was reconstructed with Prolene mesh in 12 patients and with autogenous rib in 3. Sixty-three muscles were transposed in 43 patients. Twelve omental transpositions were performed (8 for primary treatment and 4 for salvage of a failed muscle flap). Hospitalization averaged 20.2 days. There was one operative death (at 29 days). Partial flap necrosis occurred in 10 patients. Mesh was removed in three patients. There were 14 late deaths, most from recurrent tumor. The remaining patients had well-healed wounds and a generally improved quality of life. We conclude that aggressive resection and reliable reconstruction are critical considerations in the surgical management of this perplexing clinical problem

  7. Mesh Network Architecture for Enabling Inter-Spacecraft Communication (United States)

    Becker, Christopher; Merrill, Garrick


    To enable communication between spacecraft operating in a formation or small constellation, a mesh network architecture was developed and tested using a time division multiple access (TDMA) communication scheme. The network is designed to allow for the exchange of telemetry and other data between spacecraft to enable collaboration between small spacecraft. The system uses a peer-to-peer topology with no central router, so that it does not have a single point of failure. The mesh network is dynamically configurable to allow for addition and subtraction of new spacecraft into the communication network. Flight testing was performed using an unmanned aerial system (UAS) formation acting as a spacecraft analogue and providing a stressing environment to prove mesh network performance. The mesh network was primarily devised to provide low latency, high frequency communication but is flexible and can also be configured to provide higher bandwidth for applications desiring high data throughput. The network includes a relay functionality that extends the maximum range between spacecraft in the network by relaying data from node to node. The mesh network control is implemented completely in software making it hardware agnostic, thereby allowing it to function with a wide variety of existing radios and computing platforms..

  8. Influence of reinforcement mesh configuration for improvement of concrete durability (United States)

    Pan, Chong-gen; Jin, Wei-liang; Mao, Jiang-hong; Zhang, Hua; Sun, Li-hao; Wei, Dong


    Steel bar in concrete structures under harsh environmental conditions, such as chlorine corrosion, seriously affects its service life. Bidirectional electromigration rehabilitation (BIEM) is a new method of repair technology for reinforced concrete structures in such chloride corrosion environments. By applying the BIEM, chloride ions can be removed from the concrete and the migrating corrosion inhibit can be moved to the steel surface. In conventional engineering, the concrete structure is often configured with a multi-layer steel mesh. However, the effect of the BIEM in such structures has not yet been investigated. In this paper, the relevant simulation test is carried out to study the migration law of chloride ions and the migrating corrosion inhibitor in a concrete specimen with complex steel mesh under different energizing modes. The results show that the efficiency of the BIEM increases 50% in both the monolayer steel mesh and the double-layer steel mesh. By using the single-sided BIEM, 87% of the chloride ions are removed from the steel surface. The different step modes can affect the chloride ion removal. The chloride ions within the range of the reinforcement protective cover are easier to be removed than those in the concrete between the two layers of steel mesh. However, the amount of migrating corrosion inhibitor is larger in the latter circumstances.

  9. Parallel Tetrahedral Mesh Adaptation with Dynamic Load Balancing (United States)

    Oliker, Leonid; Biswas, Rupak; Gabow, Harold N.


    The ability to dynamically adapt an unstructured grid is a powerful tool for efficiently solving computational problems with evolving physical features. In this paper, we report on our experience parallelizing an edge-based adaptation scheme, called 3D_TAG. using message passing. Results show excellent speedup when a realistic helicopter rotor mesh is randomly refined. However. performance deteriorates when the mesh is refined using a solution-based error indicator since mesh adaptation for practical problems occurs in a localized region., creating a severe load imbalance. To address this problem, we have developed PLUM, a global dynamic load balancing framework for adaptive numerical computations. Even though PLUM primarily balances processor workloads for the solution phase, it reduces the load imbalance problem within mesh adaptation by repartitioning the mesh after targeting edges for refinement but before the actual subdivision. This dramatically improves the performance of parallel 3D_TAG since refinement occurs in a more load balanced fashion. We also present optimal and heuristic algorithms that, when applied to the default mapping of a parallel repartitioner, significantly reduce the data redistribution overhead. Finally, portability is examined by comparing performance on three state-of-the-art parallel machines.

  10. Approximation of scalar and vector transport problems on polyhedral meshes

    International Nuclear Information System (INIS)

    Cantin, Pierre


    This thesis analyzes, at the continuous and at the discrete level on polyhedral meshes, the scalar and the vector transport problems in three-dimensional domains. These problems are composed of a diffusive term, an advective term, and a reactive term. In the context of Friedrichs systems, the continuous problems are analyzed in Lebesgue graph spaces. The classical positivity assumption on the Friedrichs tensor is generalized so as to consider the case of practical interest where this tensor takes null or slightly negative values. A new scheme converging at the order 3/2 is devised for the scalar advection-reaction problem using scalar degrees of freedom attached to mesh vertices. Two new schemes considering as well scalar degrees of freedom attached to mesh vertices are devised for the scalar transport problem and are robust with respect to the dominant regime. The first scheme converges at the order 1/2 when advection effects are dominant and at the order 1 when diffusion effects are dominant. The second scheme improves the accuracy by converging at the order 3/2 when advection effects are dominant. Finally, a new scheme converging at the order 1/2 is devised for the vector advection-reaction problem considering only one scalar degree of freedom per mesh edge. The accuracy and the efficiency of all these schemes are assessed on various test cases using three-dimensional polyhedral meshes. (author)

  11. Facial reconstruction using polypropylene mesh after resection of maxillary ossifying fibroma

    Directory of Open Access Journals (Sweden)

    R. Soesanto


    Full Text Available Background: Ossifying fibroma is a variant of fibrous dysplasia and catagorized as osteofibrosis lesion. It commonly affects long bones but occasionally involves jaws. Mandible affected more common than maxilla. The treatment of ossifying fibroma include excision and resection. Excision of lesion and resection of maxilla could cause facial defect which cannot be reconstructed with bone graft. Purpose: The aim of this case report is to report the potential use of polypropylene mesh in facial reconstruction after hemimaxillectomy in patients diagnosed with ossifying fibroma of the maxilla. Case: A 17-years-old female patient came to Oral and Maxillofacial Surgery clinic, Dental Hospital, Faculty of Dentistry, Airlangga University, with chief complaint of swelling in the upper left cheek of 2 years duration which was not related to any history of toothache. Patient also complained of the itchiness and pain on the swelling area occasionally as well as salty discharge from the mass. The FNA was done and the citology result indicated a benign mesenchimal tumor. Incisonal biopsy was subsequently performed and the histopathology report confirmed the diagnosis of cementifying fibroma. Case management: Left hemimaxillectomy was done, and post surgical defect in the facial and buccal aspect was immediately reconstructed using three layers of polypropylene mesh. On follow-up, eleven months post-operatively, the patient was well and there was no facial deformity or asymmetry. Conclusion: Polypropylene mesh is a potential material for facial reconstruction as it can reduce the risk of facial deformity after hemimaxillectomy of patients with tumor of the maxilla.Latar belakang: Ossifying fibroma merupakan varian dari fibrous dysplasia dan termasuk di dalam kategori lesi osteofibrosis. Umumnya mengenai tulang panjang tetapi dapat juga mengenai rahang dan lebih banyak menyerang tulang mandibula dibanding maksila. Perawatan ossifying fibroma dilakukan dengan

  12. Using virtual ridge augmentation and 3D printing to fabricate a titanium mesh positioning device: A novel technique letter. (United States)

    Al-Ardah, Aladdin; Alqahtani, Nasser; AlHelal, Abdulaziz; Goodacre, Brian; Swamidass, Rajesh; Garbacea, Antoanela; Lozada, Jaime


    This technique describes a novel approach for planning and augmenting a large bony defect using a titanium mesh (TiMe). A 3-dimensional (3D) surgical model was virtually created from a cone beam computed tomography (CBCT) and wax-pattern of the final prosthetic outcome. The required bone volume (horizontally and vertically) was digitally augmented and then 3D printed to create a bone model. The 3D model was then used to contour the TiMe in accordance with the digital augmentation. With the contoured / preformed TiMe on the 3D printed model a positioning jig was made to aid the placement of the TiMe as planned during surgery. Although this technique does not impact the final outcome of the augmentation procedure, it allows the clinician to virtually design the augmentation, preform and contour the TiMe, and create a positioning jig reducing surgical time and error.

  13. Parastomal Hernia Repair with a 3D Funnel Intraperitoneal Mesh Device and Same-Sided Stoma Relocation: Results of 56 Cases. (United States)

    Fischer, Ines; Wundsam, Helwig; Mitteregger, Martin; Köhler, Gernot


    Parastomal hernias (PSHs) are a common and challenging issue. In previous studies, three-dimensional (3D) funnel mesh devices have been used successfully for the repair of PSHs. We performed an analysis of prospectively collected data of patients who underwent a same-sided stoma reposition with 3D funnel-shaped mesh augmentation in intraperitoneal (IPOM) position at our department between the years of 2012 and 2015. Primary outcome parameters were intra- and postoperative surgical complications and recurrence rate during the follow-up period. Fifty-six patients could be included in this analysis. PSH repair was performed in 89.3% as elective surgery and in 73% in laparoscopic technique. A concomitant incisional hernia (EHS type 2 and 4) was found in 50% and repaired in a single-step procedure with PSH. Major postoperative complications requiring redo surgery (Clavien-Dindo ≥3b) were identified in 8.9% (5/56). Overall recurrence rate was 12.5% (7/56). Median follow-up time was 38 months, and a 1-year follow-up rate of 96.4% was reached. PSH repair with 3D funnel mesh in IPOM technique is safe, efficient and easy to perform in laparoscopic and open surgical approaches providing advantageous results compared to other techniques. Furthermore, simultaneous detection and treatment of concomitant incisional hernias has shown favorable. However, the mesh funnel distends and becomes shortened encasing a bulky bowel mesentery and further shrinkage happens eccentric. Changing mesh construction according to lengthening the funnel could possibly lead to reduction in recurrence.

  14. Mesh Nanoelectronics: Seamless Integration of Electronics with Tissues. (United States)

    Dai, Xiaochuan; Hong, Guosong; Gao, Teng; Lieber, Charles M


    Nanobioelectronics represents a rapidly developing field with broad-ranging opportunities in fundamental biological sciences, biotechnology, and medicine. Despite this potential, seamless integration of electronics has been difficult due to fundamental mismatches, including size and mechanical properties, between the elements of the electronic and living biological systems. In this Account, we discuss the concept, development, key demonstrations, and future opportunities of mesh nanoelectronics as a general paradigm for seamless integration of electronics within synthetic tissues and live animals. We first describe the design and realization of hybrid synthetic tissues that are innervated in three dimensions (3D) with mesh nanoelectronics where the mesh serves as both as a tissue scaffold and as a platform of addressable electronic devices for monitoring and manipulating tissue behavior. Specific examples of tissue/nanoelectronic mesh hybrids highlighted include 3D neural tissue, cardiac patches, and vascular constructs, where the nanoelectronic devices have been used to carry out real-time 3D recording of electrophysiological and chemical signals in the tissues. This novel platform was also exploited for time-dependent 3D spatiotemporal mapping of cardiac tissue action potentials during cell culture and tissue maturation as well as in response to injection of pharmacological agents. The extension to simultaneous real-time monitoring and active control of tissue behavior is further discussed for multifunctional mesh nanoelectronics incorporating both recording and stimulation devices, providing the unique capability of bidirectional interfaces to cardiac tissue. In the case of live animals, new challenges must be addressed, including minimally invasive implantation, absence of deleterious chronic tissue response, and long-term capability for monitoring and modulating tissue activity. We discuss each of these topics in the context of implantation of mesh

  15. Multiphase flow of immiscible fluids on unstructured moving meshes

    DEFF Research Database (Denmark)

    Misztal, Marek Krzysztof; Erleben, Kenny; Bargteil, Adam


    In this paper, we present a method for animating multiphase flow of immiscible fluids using unstructured moving meshes. Our underlying discretization is an unstructured tetrahedral mesh, the deformable simplicial complex (DSC), that moves with the flow in a Lagrangian manner. Mesh optimization...... operations improve element quality and avoid element inversion. In the context of multiphase flow, we guarantee that every element is occupied by a single fluid and, consequently, the interface between fluids is represented by a set of faces in the simplicial complex. This approach ensures...... that the underlying discretization matches the physics and avoids the additional book-keeping required in grid-based methods where multiple fluids may occupy the same cell. Our Lagrangian approach naturally leads us to adopt a finite element approach to simulation, in contrast to the finite volume approaches adopted...

  16. CCD Photometry of bright stars using objective wire mesh

    Energy Technology Data Exchange (ETDEWEB)

    Kamiński, Krzysztof; Zgórz, Marika [Astronomical Observatory Institute, Faculty of Physics, A. Mickiewicz University, Słoneczna 36, 60-286 Poznań (Poland); Schwarzenberg-Czerny, Aleksander, E-mail: [Copernicus Astronomical Centre, ul. Bartycka 18, PL 00-716 Warsaw (Poland)


    Obtaining accurate photometry of bright stars from the ground remains problematic due to the danger of overexposing the target and/or the lack of suitable nearby comparison stars. The century-old method of using objective wire mesh to produce multiple stellar images seems promising for the precise CCD photometry of such stars. Furthermore, our tests on β Cep and its comparison star, differing by 5 mag, are very encouraging. Using a CCD camera and a 20 cm telescope with the objective covered by a plastic wire mesh, in poor weather conditions, we obtained differential photometry with a precision of 4.5 mmag per two minute exposure. Our technique is flexible and may be tuned to cover a range as big as 6-8 mag. We discuss the possibility of installing a wire mesh directly in the filter wheel.

  17. MESH2D Grid generator design and use

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    Mesh2d is a Fortran90 program originally designed to generate two-dimensional structured grids of the form [x(i),y(i,j)] where [x,y] are grid coordinates identified by indices (i,j). x-coordinates depending only on index i implies strictly vertical x-grid lines, whereas the y-grid lines can undulate. Mesh2d also assigns an integer material type to each grid cell, mtyp(i,j), in a user-specified manner. The complete grid is specified through three separate input files defining the x(i), y(i,j), and mtyp(i,j) variations. Since the original development effort, Mesh2d has been extended to more general two-dimensional structured grids of the form [x(i,j),(i,j)].

  18. Development of unstructured mesh generator on parallel computers

    International Nuclear Information System (INIS)

    Muramatsu, Kazuhiro; Shimada, Akio; Murakami, Hiroyuki; Higashida, Akihiro; Wakatsuki, Shigeto


    A general-purpose unstructured mesh generator, 'GRID3D/UNST', has been developed on parallel computers. High-speed operations and large-scale memory capacity of parallel computers enable the system to generate a large-scale mesh at high speed. As a matter of fact, the system generates large-scale mesh composed of 2,400,000 nodes and 14,000,000 elements about 1.5 hours on HITACHI SR2201, 64 PEs (Processing Elements) through 2.5 hours pre-process on SUN. Also the system is built on standard FORTRAN, C and Motif, and therefore has high portability. The system enables us to solve a large-scale problem that has been impossible to be solved, and to break new ground in the field of science and engineering. (author)

  19. Sending policies in dynamic wireless mesh using network coding

    DEFF Research Database (Denmark)

    Pandi, Sreekrishna; Fitzek, Frank; Pihl, Jeppe


    This paper demonstrates the quick prototyping capabilities of the Python-Kodo library for network coding based performance evaluation and investigates the problem of data redundancy in a network coded wireless mesh with opportunistic overhearing. By means of several wireless meshed architectures...... of appropriate relays. Finally, various sending policies that can be employed by the nodes in order to improve the overall transmission efficiency in a dynamic wireless mesh network are discussed and their performance is analysed on the constructed simulation setup....... simulated on the constructed test-bed, the advantage of network coding over state of the art routing schemes and the challenges of this new technology are shown. By providing maximum control of the network coding parameters and the simulation environment to the user, the test-bed facilitates quick...

  20. Multi-phase Volume Segmentation with Tetrahedral Mesh

    DEFF Research Database (Denmark)

    Nguyen Trung, Tuan; Dahl, Vedrana Andersen; Bærentzen, Jakob Andreas

    Volume segmentation is efficient for reconstructing material structure, which is important for several analyses, e.g. simulation with finite element method, measurement of quantitative information like surface area, surface curvature, volume, etc. We are concerned about the representations of the 3....... In many cases, the voxel grids are converted to explicit meshes, however the conversion may reduce the accuracy of the segmentations, and the effort for meshing is also not trivial. On the other side, methods using unstructured meshes have difficulty in handling topology changes. To reduce the complexity......, previous methods only represent the surfaces, thus they only segment a single region without exterior or interior information (e.g. holes). Finally, yet importantly, previous methods of both representations have issues with multi-material segmentation, where vacuum and overlapping between surfaces occur...

  1. Dynamic Resource Management in 802.11 Wireless Mesh Networks

    Directory of Open Access Journals (Sweden)

    George Athanasiou


    Full Text Available The association/handoff procedures are important components in a balanced operation of 802.11-based wireless mesh networks. In this paper, we introduce the concept of cooperative association where the stations (STA can share useful information in order to improve the performance of the association/reassociation procedures. Furthermore, in this work we introduce a load balancing mechanism that can be applied in mesh networks. This mechanism operates in a cross-layer manner taking into account uplink and downlink channel information, routing information, and congestion-based information. Our load balancing mechanism is based on a fairness index that is measured at each access point (AP neighborhood. This index reflects the way the communication load is shared in the neighboring APs. The iterative heuristic algorithms that we propose controls the communication load of each mesh AP in a distributed manner. We evaluate the performance of our mechanisms through OPNET simulations.

  2. Study on boundary search method for DFM mesh generation

    Directory of Open Access Journals (Sweden)

    Li Ri


    Full Text Available The boundary mesh of the casting model was determined by direct calculation on the triangular facets extracted from the STL file of the 3D model. Then the inner and outer grids of the model were identified by the algorithm in which we named Inner Seed Grid Method. Finally, a program to automatically generate a 3D FDM mesh was compiled. In the paper, a method named Triangle Contraction Search Method (TCSM was put forward to ensure not losing the boundary grids; while an algorithm to search inner seed grids to identify inner/outer grids of the casting model was also brought forward. Our algorithm was simple, clear and easy to construct program. Three examples for the casting mesh generation testified the validity of the program.

  3. Tetrahedral meshing via maximal Poisson-disk sampling

    KAUST Repository

    Guo, Jianwei


    In this paper, we propose a simple yet effective method to generate 3D-conforming tetrahedral meshes from closed 2-manifold surfaces. Our approach is inspired by recent work on maximal Poisson-disk sampling (MPS), which can generate well-distributed point sets in arbitrary domains. We first perform MPS on the boundary of the input domain, we then sample the interior of the domain, and we finally extract the tetrahedral mesh from the samples by using 3D Delaunay or regular triangulation for uniform or adaptive sampling, respectively. We also propose an efficient optimization strategy to protect the domain boundaries and to remove slivers to improve the meshing quality. We present various experimental results to illustrate the efficiency and the robustness of our proposed approach. We demonstrate that the performance and quality (e.g., minimal dihedral angle) of our approach are superior to current state-of-the-art optimization-based approaches.

  4. Automatic Matching of Multi-scale Road Networks under the Constraints of Smaller Scale Road Meshes

    Directory of Open Access Journals (Sweden)

    PEI Hongxing


    Full Text Available A new method is proposed to achieve automatic matching for multi-scale roads under the constraints of the smaller scale data. Firstly, meshes should be extracted from the two different scales road data. Secondly, several basic meshes in the larger scale road network will be merged as a composite one, which will be matched with one mesh from the smaller scale road network, so that the meshes with many-to-one and one-to-one matching relationships will be matched. Thirdly, meshes from the two different scale road data with many-to-many matching relationships will be matched. Finally, road will be classified into two categories under the constraints of meshes: mesh border roads and mesh internal roads, and then matching will be done in their own categories according to the matching relationships between the two scales meshes. The results showed that roads from different scale will be more precisely matched.

  5. First Case Report of Acute Renal Failure After Mesh-Plug Inguinal Hernia Repair in a Kidney Transplant Recipient (United States)

    Veroux, Massimiliano; Ardita, Vincenzo; Zerbo, Domenico; Caglià, Pietro; Palmucci, Stefano; Sinagra, Nunziata; Giaquinta, Alessia; Veroux, Pierfrancesco


    Abstract Acute renal failure due to ureter compression after a mesh-plug inguinal repair in a kidney transplant recipient has not been previously reported to our knowledge. A 62-year-old man, who successfully underwent kidney transplantation from a deceased donor 6 years earlier, was admitted for elective repair of a direct inguinal hernia. The patient underwent an open mesh-plug repair of the inguinal hernia with placement of a plug in the preperitoneal space. We did not observe the transplanted ureter and bladder during dissection of the inguinal canal. Immediately after surgery, the patient became anuric, and a graft sonography demonstrated massive hydronephrosis. The serum creatinine level increased rapidly, and the patient underwent an emergency reoperation 8 hours later. During surgery, we did not identify the ureter but, immediately after plug removal, urine output increased progressively. We completed the hernia repair using the standard technique, without plug interposition, and the postoperative course was uneventful with complete resolution of graft dysfunction 3 days later. Furthermore, we reviewed the clinical features of complications related to inguinal hernia surgery. An increased risk of urological complications was reported recently in patients with a previous prosthetic hernia repair undergoing kidney transplantation, mainly due to the mesh adhesion to surrounding structures, making the extraperitoneal dissection during the transplant surgery very challenging. Moreover, older male kidney transplant recipients undergoing an inguinal hernia repair may be at higher risk of graft dysfunction due to inguinal herniation of a transplanted ureter. Mesh-plug inguinal hernia repair is a safe surgical technique, but this unique case suggests that kidney transplant recipients with inguinal hernia may be at higher risk of serious urological complications. Surgeons must be aware of the graft and ureter position before proceeding with hernia repair. A prompt

  6. First Case Report of Acute Renal Failure After Mesh-Plug Inguinal Hernia Repair in a Kidney Transplant Recipient. (United States)

    Veroux, Massimiliano; Ardita, Vincenzo; Zerbo, Domenico; Caglià, Pietro; Palmucci, Stefano; Sinagra, Nunziata; Giaquinta, Alessia; Veroux, Pierfrancesco


    Acute renal failure due to ureter compression after a mesh-plug inguinal repair in a kidney transplant recipient has not been previously reported to our knowledge. A 62-year-old man, who successfully underwent kidney transplantation from a deceased donor 6 years earlier, was admitted for elective repair of a direct inguinal hernia. The patient underwent an open mesh-plug repair of the inguinal hernia with placement of a plug in the preperitoneal space. We did not observe the transplanted ureter and bladder during dissection of the inguinal canal. Immediately after surgery, the patient became anuric, and a graft sonography demonstrated massive hydronephrosis. The serum creatinine level increased rapidly, and the patient underwent an emergency reoperation 8 hours later. During surgery, we did not identify the ureter but, immediately after plug removal, urine output increased progressively. We completed the hernia repair using the standard technique, without plug interposition, and the postoperative course was uneventful with complete resolution of graft dysfunction 3 days later. Furthermore, we reviewed the clinical features of complications related to inguinal hernia surgery. An increased risk of urological complications was reported recently in patients with a previous prosthetic hernia repair undergoing kidney transplantation, mainly due to the mesh adhesion to surrounding structures, making the extraperitoneal dissection during the transplant surgery very challenging. Moreover, older male kidney transplant recipients undergoing an inguinal hernia repair may be at higher risk of graft dysfunction due to inguinal herniation of a transplanted ureter. Mesh-plug inguinal hernia repair is a safe surgical technique, but this unique case suggests that kidney transplant recipients with inguinal hernia may be at higher risk of serious urological complications. Surgeons must be aware of the graft and ureter position before proceeding with hernia repair. A prompt diagnosis


    Directory of Open Access Journals (Sweden)



    Full Text Available A parametric study has been carried out using the software REGEN 3.3 to optimize the regenerator of a miniature Stirling cryocooler operating with a warm end temperature of 300 K and cold end temperature of 80 K. Regenerator designs which produce the maximum coefficient of performance (COP of the system is considered as an optimized regenerator. The length and diameter of the regenerator were fixed from the cooler system requirements. Single mesh regenerators made of 200, 250, 300, 400 and 450 Stainless Steel wire meshes were considered and the optimum phase angle and mesh size were obtained. A maximum COP of 0.1475 was obtained for 300 mesh regenerator at 70° phase angle. Then multi mesh regenerators were considered with finer mesh on the cold end and coarser mesh on the hot end. The optimum size and length of each mesh in the multi mesh regenerator and the optimum phase angle were calculated. The maximum COP of 0.156 was obtained for 200 300-400 multi mesh regenerator at 70° phase angle. The COP and net refrigeration obtained for an optimized multi mesh regenerator was found to be significantly higher than that of a single mesh regenerator. Thus a multi mesh regenerator design with a proper combination of regenerator mesh size and length can enhance the regenerator effectiveness.

  8. Grouper: A Compact, Streamable Triangle Mesh Data Structure

    Energy Technology Data Exchange (ETDEWEB)

    Luffel, Mark [Georgia Inst. of Technology, Atlanta, GA (United States). Visualization and Usability Center (GVU); Gurung, Topraj [Georgia Inst. of Technology, Atlanta, GA (United States). Visualization and Usability Center (GVU); Lindstrom, Peter [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rossignac, Jarek [Georgia Inst. of Technology, Atlanta, GA (United States). Visualization and Usability Center (GVU)


    Here, we present Grouper: an all-in-one compact file format, random-access data structure, and streamable representation for large triangle meshes. Similarly to the recently published SQuad representation, Grouper represents the geometry and connectivity of a mesh by grouping vertices and triangles into fixed-size records, most of which store two adjacent triangles and a shared vertex. Unlike SQuad, however, Grouper interleaves geometry with connectivity and uses a new connectivity representation to ensure that vertices and triangles can be stored in a coherent order that enables memory-efficient sequential stream processing. We also present a linear-time construction algorithm that allows streaming out Grouper meshes using a small memory footprint while preserving the initial ordering of vertices. In this construction, we show how the problem of assigning vertices and triangles to groups reduces to a well-known NP-hard optimization problem, and present a simple yet effective heuristic solution that performs well in practice. Our array-based Grouper representation also doubles as a triangle mesh data structure that allows direct access to vertices and triangles. Storing only about two integer references per triangle-i.e., less than the three vertex references stored with each triangle in a conventional indexed mesh format-Grouper answers both incidence and adjacency queries in amortized constant time. Our compact representation enables data-parallel processing on multicore computers, instant partitioning and fast transmission for distributed processing, as well as efficient out-of-core access. We demonstrate the versatility and performance benefits of Grouper using a suite of example meshes and processing kernels.

  9. Prevention of a parastomal hernia by biological mesh reinforcement

    Directory of Open Access Journals (Sweden)

    René H Fortelny


    Full Text Available Introduction: In the field of hernia prevention the prophylactic mesh-reinforcement of stoma-sites is one of the most controversially discussed issues. The incidence of parastomal hernias in the literature reported to be up to 48.1% after end colostomy and up to 30.8 % after of loop colostomy respectively, but still remains uncertain due to diagnostic variety of clinical or radiological methods, heterogeneous patient groups and variable follow-up intervals respectively. Anyway, the published data regarding the use of synthetic or bio-prostethic meshes in the prevention of parastomal hernia at the primary operation are very scarce. Methods: A literature search of the Medline database in terms of biological prophylactic mesh implantation in stoma creation identified 6 systematic reviews, 2 randomized controlled trials (RCT, 2 case controlled studies and 1 technical report. Results: In a systematic review focusing on the prevention of parastomal hernia including only RCTs encompassing one RCT using bio-prosthetic mesh the incidence of herniation was 12.5 % compared to 53% in the control group (p<0.0001. In 1 RCT and 2 case control studies respectively, there was a significant smaller incidence of parastomal herniation as well as a similar complication rate compared to the control group respectively. Only in 1 RCT no significant difference regarding the incidence of parastomal hernia was reported with comparable complication rates. Conclusion: Thus so far 2 RCT and 2 case control studies are published with prophylactic bio prosthetic reinforcement in stoma sites. The majority revealed significant better results in terms of parastomal herniation and without any mesh related complications in comparison to the non mesh group. Further multicenter RCT are required to achieve a sufficient level of recommendation.

  10. Implant-based breast reconstruction using a titanium-coated polypropylene mesh (TiLOOP Bra): a multicenter study of 231 cases. (United States)

    Dieterich, Max; Paepke, Stefan; Zwiefel, Karin; Dieterich, Holger; Blohmer, Jens; Faridi, Andree; Klein, Evelyn; Gerber, Bernd; Nestle-Kraemling, Carolin


    An alternative to implant-based breast reconstruction using acellular dermal matrix is the use of a titanium-coated polypropylene mesh. The mesh was approved for implant-based breast reconstruction in Europe in 2008, but only limited clinical data are available. Two hundred seven patients (231 breasts) with skin-sparing/nipple-sparing or modified radical mastectomy and immediate or delayed implant-based breast reconstruction using titanium-coated polypropylene mesh were evaluated retrospectively. The primary endpoints were identification of patient-related and surgical factors that were predictive for an adverse outcome and the development of recommendations for patients eligible for implant-based breast reconstruction using the mesh. Complications were divided into major (need for additional surgery), minor (conservative treatment), and implant loss. Univariate and multivariate logistic regression analyses were performed to determine the influence of the patient- and procedure-related characteristics on postoperative complications and implant loss. No risk factors were observed for patient-associated complications. Major complications occurred in 13.4 percent, minor complications in 15.6 percent, and implant loss in 8.7 percent of patients. Univariate analysis revealed procedure-related risk factors for postoperative complications with a bilateral procedure (p = 0.013) or skin expansion before implant surgery (p = 0.043). Multivariate analysis confirmed these risk factors and revealed an increased risk for implant loss in patients with skin necrosis (p < 0.001) and capsule fibrosis (p < 0.001). This titanium-coated polypropylene mesh shows acceptable complication rates and can be a helpful device in implant-based breast reconstruction. The mesh should only be used in primary cases and, when adhering to the proposed indications, is a safe and convenient option in implant-based breast reconstruction. Risk, III.

  11. Value for money in particle-mesh plasma simulations

    International Nuclear Information System (INIS)

    Eastwood, J.W.


    The established particle-mesh method of simulating a collisionless plasma is discussed. Problems are outlined, and it is stated that given constraints on mesh size and particle number, the only way to adjust the compromise between dispersive forces, collision time and heating time is by altering the force calculating cycle. In 'value for money', schemes, matching of parts of the force calculation cycle is optimized. Interparticle forces are considered. Optimized combinations of elements of the force calculation cycle are compared. Following sections cover the dispersion relation, and comparisons with other schemes. (U.K.)

  12. Implementation of LDG method for 3D unstructured meshes

    Directory of Open Access Journals (Sweden)

    Filander A. Sequeira Chavarría


    Full Text Available This paper describes an implementation of the Local Discontinuous Galerkin method (LDG applied to elliptic problems in 3D. The implementation of the major operators is discussed. In particular the use of higher-order approximations and unstructured meshes. Efficient data structures that allow fast assembly of the linear system in the mixed formulation are described in detail. Keywords: Discontinuous finite element methods, high-order approximations, unstructured meshes, object-oriented programming. Mathematics Subject Classification: 65K05, 65N30, 65N55.

  13. Some Aspects of Multigrid Methods on Non-Structured Meshes (United States)

    Guillard, H.; Marco, N.


    To solve a given fine mesh problem, the design of a multigrid method requires the definition of coarse levels, associated coarse grid operators and inter-grid transfer operators. For non-structured simplified meshes, these definitions can rely on the use of non-nested triangulations. These definitions can also be founded on agglomeration/aggregation techniques in a purely algebraic manner. This paper analyzes these two options, shows the connections of the volume-agglomeration method with algebraic methods and proposes a new definition of prolongation operator suitable for the application of the volume-agglomeration method to elliptic problems.

  14. Reactor physics verification of the MCNP6 unstructured mesh capability

    International Nuclear Information System (INIS)

    Burke, T. P.; Kiedrowski, B. C.; Martz, R. L.; Martin, W. R.


    The Monte Carlo software package MCNP6 has the ability to transport particles on unstructured meshes generated from the Computed-Aided Engineering software Abaqus. Verification is performed using benchmarks with features relevant to reactor physics - Big Ten and the C5G7 computational benchmark. Various meshing strategies are tested and results are compared to reference solutions. Computational performance results are also given. The conclusions show MCNP6 is capable of producing accurate calculations for reactor physics geometries and the computational requirements for small lattice benchmarks are reasonable on modern computing platforms. (authors)

  15. Solution adaptive meshes with a hyperbolic grid generator (United States)

    Klopfer, G. H.

    An alternative numerical procedure to generate solution-adaptive grids for use in CFD simulations is developed analytically and demonstrated. The approach is based on the hyperbolic generation scheme of Steger and Chausee (1980), with terms added to achieve line clustering while fulfilling orthogonality and smoothness requirements. The formulation of the method is outlined, and adapted meshes for a shock-shock interaction at freestream Mach number 8.03 and Reynolds number 387,500 are presented graphically. The hyperbolic approach is shown to be significantly faster than comparable elliptic-grid methods and capable of producing an arbitrarily high degree of clustering on structured meshes.

  16. 802.11s Wireless Mesh Network Visualization Application (United States)

    Mauldin, James Alexander


    Results of past experimentation at NASA Johnson Space Center showed that the IEEE 802.11s standard has better performance than the widely implemented alternative protocol B.A.T.M.A.N (Better Approach to Mobile Ad hoc Networking). 802.11s is now formally incorporated into the Wi- Fi 802.11-2012 standard, which specifies a hybrid wireless mesh networking protocol (HWMP). In order to quickly analyze changes to the routing algorithm and to support optimizing the mesh network behavior for our intended application a visualization tool was developed by modifying and integrating open source tools.

  17. Form-finding with polyhedral meshes made simple

    KAUST Repository

    Tang, Chengcheng


    We solve the form-finding problem for polyhedral meshes in a way which combines form, function and fabrication; taking care of user-specified constraints like boundary interpolation, planarity of faces, statics, panel size and shape, enclosed volume, and cost. Our main application is the interactive modeling of meshes for architectural and industrial design. Our approach can be described as guided exploration of the constraint space whose algebraic structure is simplified by introducing auxiliary variables and ensuring that constraints are at most quadratic.

  18. Assembly meshing of abrasive waterjet nozzle erosion simulation (United States)

    Kamarudin, N. H.; Mebrahitom, A.; Azhari, A.


    Computational Fluid Dynamics (CFD) softwares have been prevalent in Abrasive Waterjet (AWJ) Modelling for optimization and prediction. However, there are many different methods in approaching a single problem especially in predicting the erosion rate of nozzle which is critical in influencing kerf quality of AWJ cutting. In this paper, three main methods of assembly meshing for an abrasive waterjet erosion were simulated which is Quadrilateral, Cutcell and Tetrahedrons and each processing time, quality of convergence and accuracy of results are discussed. Results shows that Quadrilateral mesh prevails in the mentioned category followed by Tetrahedrons and Cutcell.

  19. Surface functionalisation of polypropylene hernia-repair meshes by RF-activated plasma polymerisation of acrylic acid and silver nanoparticles

    International Nuclear Information System (INIS)

    Nisticò, Roberto; Rosellini, Andrea; Rivolo, Paola; Faga, Maria Giulia; Lamberti, Roberta; Martorana, Selanna; Castellino, Micaela; Virga, Alessandro; Mandracci, Pietro; Malandrino, Mery; Magnacca, Giuliana


    Graphical abstract: - Highlights: • Polypropylene meshes for hernioplasty were surface functionalised via plasma-polymerisation to confer adhesive properties. • Subsequently, silver nanoparticles were loaded to add antibacterial activity. • Materials were physico-chemical characterised and adhesive properties evaluated. - Abstract: Hernia diseases are among the most common and diffuse causes of surgical interventions. Unfortunately, still nowadays there are different phenomena which can cause the hernioplasty failure, for instance post-operative prostheses displacements and proliferation of bacteria in the surgical site. In order to limit these problems, commercial polypropylene (PP) and polypropylene/Teflon (PP/PTFE) bi-material meshes were surface functionalised to confer adhesive properties (and therefore reduce undesired displacements) using polyacrylic acid synthesized by plasma polymerisation (PPAA). A broad physico-chemical and morphological characterisation was carried out and adhesion properties were investigated by means of atomic force microscopy (AFM) used in force/distance (F/D) mode. Once biomedical devices surface was functionalised by PPAA coating, metallic silver nanoparticles (AgNPs) with antimicrobial properties were synthesised and loaded onto the polymeric prostheses. The effect of the PPAA, containing carboxylic functionalities, adhesive coating towards AgNPs loading capacity was verified by means of X-ray photoelectron spectroscopy (XPS). Preliminary measurement of the Ag loaded amount and release in water were also investigated via inductively coupled plasma atomic emission spectroscopy (ICP-AES). Promising results were obtained for the functionalised biomaterials, encouraging future in vitro and in vivo tests

  20. Surgical medical record

    DEFF Research Database (Denmark)

    Bulow, S.


    A medical record is presented on the basis of selected linguistic pearls collected over the years from surgical case records Udgivelsesdato: 2008/12/15......A medical record is presented on the basis of selected linguistic pearls collected over the years from surgical case records Udgivelsesdato: 2008/12/15...

  1. Recognizing surgical patterns

    NARCIS (Netherlands)

    Bouarfa, L.


    In the Netherlands, each year over 1700 patients die from preventable surgical errors. Numerous initiatives to improve surgical practice have had some impact, but problems persist. Despite the introduction of checklists and protocols, patient safety in surgery remains a continuing challenge. This is

  2. Surgical management of pain

    African Journals Online (AJOL)

    the spinal cord.[4] In this article, the reader is referred back to this illustration to understand the surgical techniques used to manage pain. Pain is caused by ... Injured dorsal root neurons discharge at higher frequencies and more spontaneously than normally. Surgical techniques. The physician should ensure that treat-.

  3. Surgical site infections

    African Journals Online (AJOL)

    the development of SSI. Complications associated with surgical site infections7. • Longer hospital stay with risk of acquiring other hospital acquired infections like pneumonia. • Require more surgical procedures. • Risk for development of resistance to antibiotics. • Risk for development of necrotizing fasciitis with skin loss.

  4. [Prospective study of laparoscopic treatment of incisional hernia by means of the use of composite mesh: indications, complications, mesh fixation materials and results]. (United States)

    Olmi, Stefano; Erba, Luigi; Magnone, Stefano; Bertolini, Aimone; Mastropasqua, Emanuele; Perego, Paolo; Massimini, Diego; Zanandrea, Guido; Russo, Roberto; Croce, Enrico


    The aim of this study was to establish the indications, safety, efficacy, feasibility and reproducibility of laparoscopic techniques in the treatment of abdominal wall defects, even of the larger kind, in order to standardise procedures and confirm the performance of the composite mesh used (Parietex, Sofradim, Trevoux, France). From January 2001 to December 2004, 185 non-selected patients (109 females, 76 males), with a mean age of 56 years (range: 26-77) and a mean BMI of 30 (range: 26-40) were included in the study; 162 patients (87.5%) had incisional hernias and 23 patients (12.5%) primary wall defects. The size of the defects treated ranged from 4 cm to 26 cm (mean: 12.1 cm). All patients underwent laparoscopic repair and all meshes were placed intraperitoneally. Over a mean follow-up period of 29 months (range: 1-48), we observed 11 postoperative complications (6.7%): 7 seromas (4.3%) which were still present after 4 weeks, one of which turned septic after several attempts at percutaneous evacuation and in which the prosthesis had to be removed laparoscopically; 3 (1.8%) experienced persistent neuralgia which disappeared after 2 months' treatment with NSAIDs, and also one case of trocar-induced haematoma. We had 4 recurrences (2.4%), all within 1 to 3 months of surgery; 1 in the size group measuring less than 9 cm and 3 in the larger defect group. Adhesiolysis was performed in 98% of all incisional hernia cases and in 7 cases (4.3%) we had to repair iatrogenic lesions of the small bowel. In 4 patients (2.5%), because of thick adhesions (1 patient) or bowel loop fixation to the previous surgical scar (3 patients), we caused complete bowel perforation repaired by laparoscopic suture. Mean operative time was 65.6 minutes (range: 28-130) and the mean hospital stay was 2.1 days (range: 1-5). We had no conversions and no mortality. We also reviewed the main methods of mesh fixation and believe that the best system at the moment is the EndoAnchor (Ethicon Endo

  5. Vacuum assisted closure therapy in the treatment of mesh infection after hernia repair. (United States)

    Tamhankar, A P; Ravi, K; Everitt, N J


    Mesh related infection after prosthetic abdominal wall hernia repair is a difficult clinical problem, particularly in an era of evolving microbial resistance. Commonly advocated treatment for such infection involves complete mesh excision which usually leaves a complicated weak wound. We report the use ofVAC therapy for mesh infections that allows mesh preservation leaving a sound wound. From june 2002 to January 2007, four patients with mesh related infection after abdominal wall hernia repair were treated with VAC therapy. Patients' notes were reviewed to gather clinical details. Mesh infection was evident after a variable period (day three to eight years) following hernia repair. Of the four patients, one had infection with methicillin resistant Staphylococcus aureus (MRSA), while the bacteriological cultures from two confirmed Staphylococcus aureus in one and a mixture of Pseudomonas and enterococcus species in the other. One patient failed to show significant bacterial growth on pus swab culture, having had prior broad-spectrum antibiotic treatment for mesh infection. Three patients had complete mesh preservation and one had partial mesh excision. All patients were treated with VAC therapy, following the drainage of their operation sites, until the visible mesh was covered with granulation (one to seven weeks). No patient had a recurrent hernia after complete wound healing. VAC therapy allows salvage of infected exposed mesh by promoting granulation through the mesh. Judicious use of VAC therapy may prevent the need of mesh excision and its wound related complications.

  6. Experimental Study Of Fog Water Harvesting By Stainless Steel Mesh

    Directory of Open Access Journals (Sweden)

    Nikhil R. Pawar


    Full Text Available The collection of fog water is a simple and sustainable technology to get hold of fresh water for various purposes. In areas where a substantial amount of fog can be obtained it is feasible to set up a stainless steel as well as black double layer plastic mesh structure for fog water harvesting. The mesh structure is directly exposed to the weather and the fog containing air is pushed through the active mesh surface by the wind. Afterward fog droplets are deposited on the active mesh area which combines to form superior droplets and run down into a gutter to storage by gravity. Fog water harvesting rates show a discrepancy from site to site. The scope of this experimental work is to review fog collection at SCOE Pune campus and to examine factors of success. This study is to synthesize the understanding of fog water harvesting in the institutional era and to analyze its benefits and boundaries for future development. The rate of fog water harvesting depends on the science of fog physics chemistry and its starring role in the hydrological cycle. This technology runs on zero energy and zeroes pollution level with cost of the benefit. The collected or treated clear water mainly could be used for different purposes as per requirement. For further development this technology public as well as government participation is needed.

  7. Optimization-based Fluid Simulation on Unstructured Meshes

    DEFF Research Database (Denmark)

    Misztal, Marek Krzysztof; Bridson, Robert; Erleben, Kenny


    can be also represented implicitly as a set of faces separating tetrahedra marked as inside from the ones marked as outside. This representation introduces insignificant and con- trollable numerical diffusion, allows robust topological adaptivity and provides both a volumetric finite element mesh...

  8. Rapid Separation of Disconnected Triangle Meshes Based on Graph Traversal

    International Nuclear Information System (INIS)

    Ji, S J; Wang, Y


    In recent year, The STL file become a de facto standard on the file presentation in CAD/CAM, computer graph and reverse engineering. When point cloud which is obtained by scanning object body using optical instrument is used to reconstruct an original model, the points cloud is presented by the STL file. Usually, datum of several separated and relative objects are stored in a single STL file, when such a file is operated by a computer, the datum in the file is firstly separated and then each element of every triangle pitch on the triangle mesh is traversed and visited and is calculated. The problem is analyzed and studied by many experts, but there is still a lack of a simple and quick algorithm. An algorithm which uses graph traversal to traverse each element of the triangle meshes and separate several disconnected triangle meshes is presented by the paper, the searching and calculating speed of the data on the triangle meshes is enhanced, memory size of the computer is reduced, complexity of the data structure is simplified and powerful guarantee is made for the next process by using this algorithm

  9. Multiphase flow of immiscible fluids on unstructured moving meshes. (United States)

    Misztal, Marek Krzysztof; Erleben, Kenny; Bargteil, Adam; Fursund, Jens; Christensen, Brian Bunch; Bærentzen, Jakob Andreas; Bridson, Robert


    In this paper, we present a method for animating multiphase flow of immiscible fluids using unstructured moving meshes. Our underlying discretization is an unstructured tetrahedral mesh, the deformable simplicial complex (DSC), that moves with the flow in a Lagrangian manner. Mesh optimization operations improve element quality and avoid element inversion. In the context of multiphase flow, we guarantee that every element is occupied by a single fluid and, consequently, the interface between fluids is represented by a set of faces in the simplicial complex. This approach ensures that the underlying discretization matches the physics and avoids the additional book-keeping required in grid-based methods where multiple fluids may occupy the same cell. Our Lagrangian approach naturally leads us to adopt a finite element approach to simulation, in contrast to the finite volume approaches adopted by a majority of fluid simulation techniques that use tetrahedral meshes. We characterize fluid simulation as an optimization problem allowing for full coupling of the pressure and velocity fields and the incorporation of a second-order surface energy. We introduce a preconditioner based on the diagonal Schur complement and solve our optimization on the GPU. We provide the results of parameter studies as well as a performance analysis of our method, together with suggestions for performance optimization.

  10. Aranha: a 2D mesh generator for triangular finite elements

    International Nuclear Information System (INIS)

    Fancello, E.A.; Salgado, A.C.; Feijoo, R.A.


    A method for generating unstructured meshes for linear and quadratic triangular finite elements is described in this paper. Some topics on the C language data structure used in the development of the program Aranha are also presented. The applicability for adaptive remeshing is shown and finally several examples are included to illustrate the performance of the method in irregular connected planar domains. (author)

  11. Split calvarial graft and titanium mesh for reconstruction of post ...

    African Journals Online (AJOL)

    Background: The goal of cranioplasty is to achieve a lifelong, stable and structural reconstruction of the cranium covered by a healthy skin and scalp flap. We present two cases of large frontal bone defect following a accident.. Cases: We describe the utilization of autogenous local split calvarial graft and titanium mesh for ...

  12. Chest wall reconstruction using Gore-Tex® dual mesh. (United States)

    Akiba, Tadashi; Marushima, Hideki; Nogi, Hiroko; Kamiya, Noriki; Kinoshita, Satoki; Takeyama, Hiroshi; Morikawa, Toshiaki


    This study aimed to evaluate the clinical outcomes of chest wall reconstruction using a relatively new expanded polytetrafluoroethylene prosthesis Gore-Tex(®) dual mesh. We reviewed charts of 11 patients who underwent bony chest wall resection from April 2006 to January 2011. Six patients underwent three ribs resection, three patients underwent two ribs resection, and the other two patients underwent sternal resection. Of six patients after three ribs resection, three underwent reconstruction using 2 mm Gore-Tex(®) dual mesh, one using Gore-Tex(®), one using Bard composite E/X, and the remaining one used no prosthesis. Three patients who underwent two ribs resection underwent no chest wall reconstruction using prosthesis. Two patients who underwent sternal resection underwent chest wall reconstruction using dual mesh with or without a vascularized musculocutaneous pedicle flap. Immediate postoperative extubation was performed in all patients, except one who was extubated the following day. No postoperative deaths or cases with paradoxical respiration occurred. Chest wall reconstruction using Gore-Tex(®) dual mesh demonstrated acceptable durability.

  13. Energy efficient topology for Wireless Mesh Networks | Negash ...

    African Journals Online (AJOL)

    We analyze the power control problem using coalition formation game theory employing utilities based on the coverage areas of the access points by associating a cost function with the utility as the payoff of the coalition members. Our work focuses on the access layer of a wireless mesh local area network. We show that by ...

  14. Adaptive unstructured meshes for finite element ocean modelling (United States)

    Power, P. W.; Pain, C. C.; Piggott, M. D.; Marshall, D. P.; Fang, F.; Umpleby, A. P.; de Oliveira, C. R. E.; Goddard, A. J. H.


    Flow in the world's oceans occurs at a wide range of spatial scales, from micro-metres to mega-metres. In particular, regions of intense flow are often highly localised, for example Western Boundary Currents. Conventional numerical ocean models generally use static meshes. The Imperial College Ocean Model (ICOM) uses advanced finite element methods to evolve the mesh to follow regions of intense flow, where high resolution may be required. Coarser resolution can be used in other areas of the flow domain. Evolution of the unstructured mesh is achieved by the use of a variety of error norms which control a self-adaptive anisotrophic meshing algorithm. The objective of this work is a reduction in computational cost, ensuring areas of fine resolution are used only where and when they are required. In this work we present some examples of an error measure being used to obtain high-quality solutions to a set of benchmark problems, for example flow over a seamount and a wind driven gyre, while using a minimal number of elements. The long term objective of this work is to define a rigorous self-adaptive technique for use in an Oceanographic context, and we present plans for the implimentation of a sensitivity based error measure.

  15. Adaptive meshes in ecosystem modelling: a way forward? (United States)

    Popova, E. E.; Ham, D. A.; Srokosz, M. A.; Piggott, M. D.


    The need to resolve physical processes occuring on many different length scales has lead to the development of ocean flow models based on unstructured and adaptive meshes. However, thus far models of biological processes have been based on fixed, structured grids which lack the ability to dynamically focus resolution on areas of developing small-scale structure. Here we will present the initial results of coupling a four component biological model to the 3D non-hydrostatic, finite element, adaptive grid ocean model ICOM (the Imperial College Ocean Model). Mesh adaptivity automatically resolves fine-scale physical or biological features as they develop, optimising computational cost by reducing resolution where it is not required. Experiments are carried out within the framework of a horizontally uniform water column. The vertical physical processes in top 500m are represented by a two equation turbulence model. The physical model is coupled to a four component biological model, which includes generic phytoplankton, zooplankton, nitrate and particular organic matter (detritus). The physical and biological model is set up to represent idealised oligotrophic conditions, typical of subtropical gyres. A stable annual cycle is achieved after a number of years of integration. We compare results obtained on a fully adaptive mesh with ones using a high resolution static mesh. We assess the computational efficiency of the adaptive approach for modelling of ecosystem processes such as the dynamics of the phytoplankton spring bloom, formation of the subsurface chlorophyll maximum and nutrient supply to the photic zone.

  16. Kinetic mesh-free method for flutter prediction in turbomachines

    Indian Academy of Sciences (India)

    Kinetic mesh-free method for flutter prediction in turbomachines. V RAMESH1,∗ and S M DESHPANDE2. 1Council for Scientific and Industrial Research, National Aerospace Laboratories,. Computational and Theoretical Fluid Dynamics Division, Bangalore 560 017, India. 2Engineering Mechanics Unit, Jawaharlal Nehru ...

  17. 28 Comparative Study of Open Mesh Repair and Desarda's No ...

    African Journals Online (AJOL)



    Dec 2, 2006 ... new technique and the open mesh repair done in a district level general hospital set up in India. Methods: This is a retrospective study of 269 ... 80 years of age and those operated under spinal or local anesthesia were included in this .... approximation to the lateral leaf. The first stitch is taken between the ...

  18. Recurrence and Pain after Mesh Repair of Inguinal Hernias ...

    African Journals Online (AJOL)

    Background: Surgery for inguinal hernias has evolved over a prolonged period of time with the main outcome of interest being recurrence and pain. Mesh hernioplasty has been practiced with increasing frequency at Kenyatta National hospital (KNH) since its formal introduction in 2006. There has not been any published ...

  19. An approach to a transparent self-healing meshed network

    DEFF Research Database (Denmark)

    Larsen, Claus Popp; Limal, Emmanuel


    A method of implementing a transparent self-healing meshed network is described here. In case of a cable break or signal detoriation, this network will perform protection switching without needing direct correspondance with the overlaying management system. This causes simpler network management...

  20. RSW Mixed Element Cell-Centered Fine Mesh (United States)

    National Aeronautics and Space Administration — This is a RSW mixed-element unstructured fine mesh for cell-centered solvers. UG3 : Grid File Name = rsw_fine_mixedcc.b8.ugrid UG3 : Quad Surface Faces= 28968 UG3 :...

  1. Mesh refinement of simulation with the AID riser transmission gamma

    International Nuclear Information System (INIS)

    Lima Filho, Hilario J.B. de; Benachour, Mohand; Dantas, Carlos C.; Brito, Marcio F.P.; Santos, Valdemir A. dos


    Type reactors Circulating Fluidized Bed (CFBR) vertical, in which the particulate and gaseous phases have flows upward (riser) have been widely used in gasification processes, combustion and fluid catalytic cracking (FCC). These biphasic reactors (gas-solid) efficiency depends largely on their hydrodynamic characteristics, and shows different behaviors in the axial and radial directions. The solids axial distribution is observed by the higher concentration in the base, getting more diluted toward the top. Radially, the solids concentration is characterized as core-annular, in which the central region is highly diluted, consisting of dispersed particles and fluid. In the present work developed a two-dimensional geometry (2D) techniques through simulations in computational fluid dynamics (CFD) to predict the gas-solid flow in the riser type CFBR through transient modeling, based on the kinetic theory of granular flow . The refinement of computational meshes provide larger amounts of information on the parameters studied, but may increase the processing time of the simulations. A minimum number of cells applied to the mesh construction was obtained by testing five meshes. The validation of the hydrodynamic parameters was performed using a range of 241Am source and detector NaI (Tl). The numerical results were provided consistent with the experimental data, indicating that the refined computational mesh in a controlled manner, improve the approximation of the expected results. (author)

  2. Shuffle-Exchange Mesh Topology for Networks-on-Chip


    Sabbaghi-Nadooshan, Reza; Modarressi, Mehdi; Sarbazi-Azad, Hamid


    The mesh topology has been used in a variety of interconnection network applications especially for NoC designs due to its desirable properties in VLSI implementation. In this chapter, we proposed a new topology based on the shuffle-exchange topology, the 2D

  3. Worlds largest particle physics laboratory selects Proxim Wireless Mesh

    CERN Multimedia


    "Proxim Wireless has announced that the European Organization for Nuclear Research (CERN), the world's largest particle physics laboratory and the birthplace of the World Wide Web, is using it's ORiNOCO AP-4000 mesh access points to extend the range of the laboratory's Wi-Fi network and to provide continuous monitoring of the lab's calorimeters" (1/2 page)

  4. Full Core Multiphysics Simulation with Offline Mesh Deformation

    Energy Technology Data Exchange (ETDEWEB)

    Merzari, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Shemon, E. R. [Argonne National Lab. (ANL), Argonne, IL (United States); Yu, Y. [Argonne National Lab. (ANL), Argonne, IL (United States); Thomas, J. W. [Argonne National Lab. (ANL), Argonne, IL (United States); Obabko, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Jain, Rajeev [Argonne National Lab. (ANL), Argonne, IL (United States); Mahadevan, Vijay [Argonne National Lab. (ANL), Argonne, IL (United States); Solberg, Jerome [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ferencz, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Whitesides, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    In this report, building on previous reports issued in FY13 we describe our continued efforts to integrate thermal/hydraulics, neutronics, and structural mechanics modeling codes to perform coupled analysis of a representative fast sodium-cooled reactor core. The focus of the present report is a full core simulation with off-line mesh deformation.

  5. Mesh refinement of simulation with the AID riser transmission gamma

    Energy Technology Data Exchange (ETDEWEB)

    Lima Filho, Hilario J.B. de; Benachour, Mohand; Dantas, Carlos C.; Brito, Marcio F.P., E-mail:, E-mail: [Universidade Federal de Pernambuco (UFPE), Pernambuco, PE (Brazil); Santos, Valdemir A. dos, E-mail: [Universidade Catolica de Pernambuco (CCT/UNICAP), Pernambuco, PE (Brazil). Dept. de Engenharia Quimica


    Type reactors Circulating Fluidized Bed (CFBR) vertical, in which the particulate and gaseous phases have flows upward (riser) have been widely used in gasification processes, combustion and fluid catalytic cracking (FCC). These biphasic reactors (gas-solid) efficiency depends largely on their hydrodynamic characteristics, and shows different behaviors in the axial and radial directions. The solids axial distribution is observed by the higher concentration in the base, getting more diluted toward the top. Radially, the solids concentration is characterized as core-annular, in which the central region is highly diluted, consisting of dispersed particles and fluid. In the present work developed a two-dimensional geometry (2D) techniques through simulations in computational fluid dynamics (CFD) to predict the gas-solid flow in the riser type CFBR through transient modeling, based on the kinetic theory of granular flow . The refinement of computational meshes provide larger amounts of information on the parameters studied, but may increase the processing time of the simulations. A minimum number of cells applied to the mesh construction was obtained by testing five meshes. The validation of the hydrodynamic parameters was performed using a range of 241Am source and detector NaI (Tl). The numerical results were provided consistent with the experimental data, indicating that the refined computational mesh in a controlled manner, improve the approximation of the expected results. (author)

  6. Meshed-Pumpkin Super-Pressure Balloon Design (United States)

    Jones, Jack; Yavrouian, Andre


    An improved, lightweight design has been proposed for super-pressure balloons used to carry scientific instruments at high altitudes in the atmosphere of Earth for times as long as 100 days. [A super-pressure balloon is one in which the pressure of the buoyant gas (typically, helium) is kept somewhat above ambient pressure in order to maintain approximately constant density and thereby regulate the altitude.] The proposed design, called "meshed pumpkin," incorporates the basic concept of the pumpkin design, which is so named because of its appearance. The pumpkin design entails less weight than does a spherical design, and the meshed-pumpkin design would reduce weight further. The basic idea of the meshed-pumpkin design is to reinforce the membrane of a pumpkin balloon by attaching a strong, lightweight fabric mesh to its outer surface. The reinforcement would make it possible to reduce the membrane mass to one-third or less of that of the basic pumpkin design while retaining sufficient strength to enable the balloon to remain at approximately constant altitude for months.

  7. Geostatistical regularization operators for geophysical inverse problems on irregular meshes (United States)

    Jordi, C.; Doetsch, J.; Günther, T.; Schmelzbach, C.; Robertsson, J. OA


    Irregular meshes allow to include complicated subsurface structures into geophysical modelling and inverse problems. The non-uniqueness of these inverse problems requires appropriate regularization that can incorporate a priori information. However, defining regularization operators for irregular discretizations is not trivial. Different schemes for calculating smoothness operators on irregular meshes have been proposed. In contrast to classical regularization constraints that are only defined using the nearest neighbours of a cell, geostatistical operators include a larger neighbourhood around a particular cell. A correlation model defines the extent of the neighbourhood and allows to incorporate information about geological structures. We propose an approach to calculate geostatistical operators for inverse problems on irregular meshes by eigendecomposition of a covariance matrix that contains the a priori geological information. Using our approach, the calculation of the operator matrix becomes tractable for 3-D inverse problems on irregular meshes. We tested the performance of the geostatistical regularization operators and compared them against the results of anisotropic smoothing in inversions of 2-D surface synthetic electrical resistivity tomography (ERT) data as well as in the inversion of a realistic 3-D cross-well synthetic ERT scenario. The inversions of 2-D ERT and seismic traveltime field data with geostatistical regularization provide results that are in good accordance with the expected geology and thus facilitate their interpretation. In particular, for layered structures the geostatistical regularization provides geologically more plausible results compared to the anisotropic smoothness constraints.

  8. Groin hernia repair in young males: mesh or sutured repair?

    DEFF Research Database (Denmark)

    Bisgaard, T; Bay-Nielsen, M; Kehlet, H


    Large-scale data for the optimal inguinal hernia repair in younger men with an indirect hernia is not available. We analysed nationwide data for risk of reoperation in younger men after a primary repair using a Lichtenstein operation or a conventional non-mesh hernia repair....

  9. Improving the efficiency of aerodynamic shape optimization on unstructured meshes

    NARCIS (Netherlands)

    G. Carpentieri; M.J.L. van Tooren; B. Koren (Barry)


    textabstractIn this paper the exact discrete adjoint of a finite volume formulation on unstructured meshes for the Euler equations in two dimensions is derived and implemented to support aerodynamic shape optimization. The accuracy of the discrete exact adjoint is demonstrated and compared with that

  10. A Generic Mesh Data Structure with Parallel Applications (United States)

    Cochran, William Kenneth, Jr.


    High performance, massively-parallel multi-physics simulations are built on efficient mesh data structures. Most data structures are designed from the bottom up, focusing on the implementation of linear algebra routines. In this thesis, we explore a top-down approach to design, evaluating the various needs of many aspects of simulation, not just…

  11. Recurrence and Pain after Mesh Repair of Inguinal Hernias

    African Journals Online (AJOL)

    from patients' files or by telephone survey where these were missing or were incomplete. Results: A total of ... system (PHS) or ultrapro hernia system (UHS). This bilayer mesh has shown promising results. Overall, ... via telephone for assessment of pain and recurrence. The follow up period ranged from 14 to 91 months.

  12. A Novel Coarsening Method for Scalable and Efficient Mesh Generation

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, A; Hysom, D; Gunney, B


    In this paper, we propose a novel mesh coarsening method called brick coarsening method. The proposed method can be used in conjunction with any graph partitioners and scales to very large meshes. This method reduces problem space by decomposing the original mesh into fixed-size blocks of nodes called bricks, layered in a similar way to conventional brick laying, and then assigning each node of the original mesh to appropriate brick. Our experiments indicate that the proposed method scales to very large meshes while allowing simple RCB partitioner to produce higher-quality partitions with significantly less edge cuts. Our results further indicate that the proposed brick-coarsening method allows more complicated partitioners like PT-Scotch to scale to very large problem size while still maintaining good partitioning performance with relatively good edge-cut metric. Graph partitioning is an important problem that has many scientific and engineering applications in such areas as VLSI design, scientific computing, and resource management. Given a graph G = (V,E), where V is the set of vertices and E is the set of edges, (k-way) graph partitioning problem is to partition the vertices of the graph (V) into k disjoint groups such that each group contains roughly equal number of vertices and the number of edges connecting vertices in different groups is minimized. Graph partitioning plays a key role in large scientific computing, especially in mesh-based computations, as it is used as a tool to minimize the volume of communication and to ensure well-balanced load across computing nodes. The impact of graph partitioning on the reduction of communication can be easily seen, for example, in different iterative methods to solve a sparse system of linear equation. Here, a graph partitioning technique is applied to the matrix, which is basically a graph in which each edge is a non-zero entry in the matrix, to allocate groups of vertices to processors in such a way that many of

  13. Loft: An Automated Mesh Generator for Stiffened Shell Aerospace Vehicles (United States)

    Eldred, Lloyd B.


    Loft is an automated mesh generation code that is designed for aerospace vehicle structures. From user input, Loft generates meshes for wings, noses, tanks, fuselage sections, thrust structures, and so on. As a mesh is generated, each element is assigned properties to mark the part of the vehicle with which it is associated. This property assignment is an extremely powerful feature that enables detailed analysis tasks, such as load application and structural sizing. This report is presented in two parts. The first part is an overview of the code and its applications. The modeling approach that was used to create the finite element meshes is described. Several applications of the code are demonstrated, including a Next Generation Launch Technology (NGLT) wing-sizing study, a lunar lander stage study, a launch vehicle shroud shape study, and a two-stage-to-orbit (TSTO) orbiter. Part two of the report is the program user manual. The manual includes in-depth tutorials and a complete command reference.

  14. Adaptive Meshing for Bi-directional Information Flows

    DEFF Research Database (Denmark)

    Nicholas, Paul; Zwierzycki, Mateusz; Stasiuk, David


    This paper describes a mesh-based modelling approach that supports the multiscale design of a panelised, thin-skinned metal structure. The term multi-scale refers to the decomposition of a design modelling problem into distinct but interdependent models associated with particular scales, and the ...

  15. A Mechanistic Study of Wetting Superhydrophobic Porous 3D Meshes (United States)

    Yohe, Stefan T.; Freedman, Jonathan D.; Falde, Eric J.; Colson, Yolonda L.; Grinstaff, Mark W.


    Superhydrophobic, porous, 3D materials composed of poly( ε -caprolactone) (PCL) and the hydrophobic polymer dopant poly(glycerol monostearate-co- ε -caprolactone) (PGC-C18) are fabricated using the electrospinning technique. These 3D materials are distinct from 2D superhydrophobic surfaces, with maintenance of air at the surface as well as within the bulk of the material. These superhydrophobic materials float in water, and when held underwater and pressed, an air bubble is released and will rise to the surface. By changing the PGC-C18 doping concentration in the meshes and/or the fiber size from the micro- to nanoscale, the long-term stability of the entrapped air layer is controlled. The rate of water infiltration into the meshes, and the resulting displacement of the entrapped air, is quantitatively measured using X-ray computed tomography. The properties of the meshes are further probed using surfactants and solvents of different surface tensions. Finally, the application of hydraulic pressure is used to quantify the breakthrough pressure to wet the meshes. The tools for fabrication and analysis of these superhydrophobic materials as well as the ability to control the robustness of the entrapped air layer are highly desirable for a number of existing and emerging applications. PMID:25309305

  16. Resource optimization scheme for multimedia-enabled wireless mesh networks. (United States)

    Ali, Amjad; Ahmed, Muhammad Ejaz; Piran, Md Jalil; Suh, Doug Young


    Wireless mesh networking is a promising technology that can support numerous multimedia applications. Multimedia applications have stringent quality of service (QoS) requirements, i.e., bandwidth, delay, jitter, and packet loss ratio. Enabling such QoS-demanding applications over wireless mesh networks (WMNs) require QoS provisioning routing protocols that lead to the network resource underutilization problem. Moreover, random topology deployment leads to have some unused network resources. Therefore, resource optimization is one of the most critical design issues in multi-hop, multi-radio WMNs enabled with multimedia applications. Resource optimization has been studied extensively in the literature for wireless Ad Hoc and sensor networks, but existing studies have not considered resource underutilization issues caused by QoS provisioning routing and random topology deployment. Finding a QoS-provisioned path in wireless mesh networks is an NP complete problem. In this paper, we propose a novel Integer Linear Programming (ILP) optimization model to reconstruct the optimal connected mesh backbone topology with a minimum number of links and relay nodes which satisfies the given end-to-end QoS demands for multimedia traffic and identification of extra resources, while maintaining redundancy. We further propose a polynomial time heuristic algorithm called Link and Node Removal Considering Residual Capacity and Traffic Demands (LNR-RCTD). Simulation studies prove that our heuristic algorithm provides near-optimal results and saves about 20% of resources from being wasted by QoS provisioning routing and random topology deployment.

  17. Deflating link buffers in a wireless mesh network

    KAUST Repository

    Jamshaid, Kamran


    We analyze the problem of buffer sizing for backlogged TCP flows in 802.11-based wireless mesh networks. Our objective is to maintain high network utilization while providing low queueing delays. Unlike wired networks where a single link buffer feeds a bottleneck link, the radio spectral resource in a mesh network is shared among a set of contending mesh routers. We account for this by formulating the buffer size problem as sizing a collective buffer distributed over a set of interfering nodes. In this paper we propose mechanisms for sizing and distributing this collective buffer among the mesh nodes constituting the network bottleneck. Our mechanism factors in the network topology and wireless link rates, improving on pre-set buffer allocations that cannot optimally work across the range of configurations achievable with 802.11 radios. We evaluate our mechanisms using simulations as well as experiments on a testbed. Our results show that we can reduce the RTT of a flow by 6× or more, at the cost of less than 10% drop in end-to-end flow throughput.

  18. Laser additive manufacturing of 3D meshes for optical applications.

    Directory of Open Access Journals (Sweden)

    Khamis Essa

    Full Text Available Selective laser melting (SLM is a widely used additive manufacturing process that can be used for printing of intricate three dimensional (3D metallic structures. Here we demonstrate the fabrication of titanium alloy Ti-6Al-4V alloy based 3D meshes with nodally-connected diamond like unit cells, with lattice spacing varying from 400 to 1000 microns. A Concept Laser M2 system equipped with laser that has a wavelength of 1075 nm, a constant beam spot size of 50μm and maximum power of 400W was used to manufacture the 3D meshes. These meshes act as optical shutters / directional transmitters and display interesting optical properties. A detailed optical characterisation was carried out and it was found that these structures can be optimised to act as scalable rotational shutters with high efficiencies and as angle selective transmission screens for protection against unwanted and dangerous radiations. The efficiency of fabricated lattice structures can be increased by enlarging the meshing size.

  19. Electroformation of Giant Vesicles on a Polymer Mesh

    Directory of Open Access Journals (Sweden)

    Yukihisa Okumura


    Full Text Available Electroformation of cell-sized lipid membrane vesicles (giant vesicles, GVs from egg yolk phosphatidylcholine under applied electric voltage was examined on a substrate of a polymer mesh placed between two planar indium tin oxide coated glass electrodes. Under appropriate conditions, GVs were formed in good yield on meshes of various polymer materials, namely, hydrophobic poly(propylene, poly(ethylene terephthalate, a carbon fiber/nylon composite, and relatively hydrophilic nylon. Arranging threads in a mesh structure with appropriate openings improved GV formation compared to simply increasing the number of threads. For optimal electroformation of GVs, the size and shape of a mesh opening were crucial. With a too large opening, GV formation deteriorated. When the sides of an opening were partially missing, GV formation did not occur efficiently. With an adequate opening, a deposited lipid solution could fill the opening, and a relatively uniform lipid deposit formed on the surface of threads after evaporation of the solvent. This could supply a sufficient amount of lipids to the opening and also prevent a lipid deposit from becoming too thick for electroformation. As a result, good GV formation was often observed in openings filled with swelled lipid.

  20. Combining abdominoplasty with mesh repair of incisional hernia: a ...

    African Journals Online (AJOL)

    ... of incisional hernia is considered the gold standard. Open repair results in an unaesthetic long midline anterior abdominal wall scar. Combining the produce with an abdominoplasty ensures an all-round satisfactions. Keywords: Abdominoplasty, incisional hernia, prosthetic mesh. Nigerian Journal of Plastic Surgery Vol.

  1. A Novel Mesh Quality Improvement Method for Boundary Elements

    Directory of Open Access Journals (Sweden)

    Hou-lin Liu


    Full Text Available In order to improve the boundary mesh quality while maintaining the essential characteristics of discrete surfaces, a new approach combining optimization-based smoothing and topology optimization is developed. The smoothing objective function is modified, in which two functions denoting boundary and interior quality, respectively, and a weight coefficient controlling boundary quality are taken into account. In addition, the existing smoothing algorithm can improve the mesh quality only by repositioning vertices of the interior mesh. Without destroying boundary conformity, bad elements with all their vertices on the boundary cannot be eliminated. Then, topology optimization is employed, and those elements are converted into other types of elements whose quality can be improved by smoothing. The practical application shows that the worst elements can be eliminated and, with the increase of weight coefficient, the average quality of boundary mesh can also be improved. Results obtained with the combined approach are compared with some common approach. It is clearly shown that it performs better than the existing approach.

  2. Modelling axisymmetric cod-ends made of different mesh types

    DEFF Research Database (Denmark)

    Priour, D.; Herrmann, Bent; O'Neill, F.G.


    Cod-ends are the rearmost part of trawl fishing gears. They collect the catch, and for many important species it is where fish selection takes place. Generally speaking they are axisymmetric, and their shape is influenced by the catch volume, the mesh shape, and the material characteristics. The ...

  3. Parallel Performance Optimizations on Unstructured Mesh-based Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Sarje, Abhinav; Song, Sukhyun; Jacobsen, Douglas; Huck, Kevin; Hollingsworth, Jeffrey; Malony, Allen; Williams, Samuel; Oliker, Leonid


    © The Authors. Published by Elsevier B.V. This paper addresses two key parallelization challenges the unstructured mesh-based ocean modeling code, MPAS-Ocean, which uses a mesh based on Voronoi tessellations: (1) load imbalance across processes, and (2) unstructured data access patterns, that inhibit intra- and inter-node performance. Our work analyzes the load imbalance due to naive partitioning of the mesh, and develops methods to generate mesh partitioning with better load balance and reduced communication. Furthermore, we present methods that minimize both inter- and intranode data movement and maximize data reuse. Our techniques include predictive ordering of data elements for higher cache efficiency, as well as communication reduction approaches. We present detailed performance data when running on thousands of cores using the Cray XC30 supercomputer and show that our optimization strategies can exceed the original performance by over 2×. Additionally, many of these solutions can be broadly applied to a wide variety of unstructured grid-based computations.


    International Nuclear Information System (INIS)

    Duffell, Paul C.; MacFadyen, Andrew I.


    We have generalized a method for the numerical solution of hyperbolic systems of equations using a dynamic Voronoi tessellation of the computational domain. The Voronoi tessellation is used to generate moving computational meshes for the solution of multidimensional systems of conservation laws in finite-volume form. The mesh-generating points are free to move with arbitrary velocity, with the choice of zero velocity resulting in an Eulerian formulation. Moving the points at the local fluid velocity makes the formulation effectively Lagrangian. We have written the TESS code to solve the equations of compressible hydrodynamics and magnetohydrodynamics for both relativistic and non-relativistic fluids on a dynamic Voronoi mesh. When run in Lagrangian mode, TESS is significantly less diffusive than fixed mesh codes and thus preserves contact discontinuities to high precision while also accurately capturing strong shock waves. TESS is written for Cartesian, spherical, and cylindrical coordinates and is modular so that auxiliary physics solvers are readily integrated into the TESS framework and so that this can be readily adapted to solve general systems of equations. We present results from a series of test problems to demonstrate the performance of TESS and to highlight some of the advantages of the dynamic tessellation method for solving challenging problems in astrophysical fluid dynamics.

  5. Palliative care and pediatric surgical oncology. (United States)

    Inserra, Alessandro; Narciso, Alessandra; Paolantonio, Guglielmo; Messina, Raffaella; Crocoli, Alessandro


    Survival rate for childhood cancer has increased in recent years, reaching as high as 70% in developed countries compared with 54% for all cancers diagnosed in the 1980s. In the remaining 30%, progression or metastatic disease leads to death and in this framework palliative care has an outstanding role though not well settled in all its facets. In this landscape, surgery has a supportive actor role integrated with other welfare aspects from which are not severable. The definition of surgical palliation has moved from the ancient definition of noncurative surgery to a group of practices performed not to cure but to alleviate an organ dysfunction offering the best quality of life possible in all the aspects of life (pain, dysfunctions, caregivers, psychosocial, etc.). To emphasize this aspect a more modern definition has been introduced: palliative therapy in whose context is comprised not only the care assistance but also the plans of care since the onset of illness, teaching the matter to surgeons in training and share paths. Literature is very poor regarding surgical aspects specifically dedicated and all researches (PubMed, Google Scholar, and Cochrane) with various meshing terms result in a more oncologic and psychosocial effort. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Deploy production sliding mesh capability with linear solver benchmarking.

    Energy Technology Data Exchange (ETDEWEB)

    Domino, Stefan P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Thomas, Stephen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Barone, Matthew F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Williams, Alan B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ananthan, Shreyas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Knaus, Robert C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Overfelt, James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sprague, Mike [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rood, Jon [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    Wind applications require the ability to simulate rotating blades. To support this use-case, a novel design-order sliding mesh algorithm has been developed and deployed. The hybrid method combines the control volume finite element methodology (CVFEM) with concepts found within a discontinuous Galerkin (DG) finite element method (FEM) to manage a sliding mesh. The method has been demonstrated to be design-order for the tested polynomial basis (P=1 and P=2) and has been deployed to provide production simulation capability for a Vestas V27 (225 kW) wind turbine. Other stationary and canonical rotating ow simulations are also presented. As the majority of wind-energy applications are driving extensive usage of hybrid meshes, a foundational study that outlines near-wall numerical behavior for a variety of element topologies is presented. Results indicate that the proposed nonlinear stabilization operator (NSO) is an effective stabilization methodology to control Gibbs phenomena at large cell Peclet numbers. The study also provides practical mesh resolution guidelines for future analysis efforts. Application-driven performance and algorithmic improvements have been carried out to increase robustness of the scheme on hybrid production wind energy meshes. Specifically, the Kokkos-based Nalu Kernel construct outlined in the FY17/Q4 ExaWind milestone has been transitioned to the hybrid mesh regime. This code base is exercised within a full V27 production run. Simulation timings for parallel search and custom ghosting are presented. As the low-Mach application space requires implicit matrix solves, the cost of matrix reinitialization has been evaluated on a variety of production meshes. Results indicate that at low element counts, i.e., fewer than 100 million elements, matrix graph initialization and preconditioner setup times are small. However, as mesh sizes increase, e.g., 500 million elements, simulation time associated with \\setup-up" costs can increase to nearly 50% of

  7. Regridding Scientific Mesh Data Using Arbitrary Cell Neighborhood Information (United States)

    Rezaei Mahdiraji, Alireza; Baumann, Peter


    A spacial case of the regrid operator uses information of neighboring cells of a cell of interest to perform interpolation on scientific meshes. Example use-cases are smoothing skewed data fields, computing value of the first derivative in oceanographic applications, etc. Using neighbors' information is proved to improve the accuracy of the computations for a cell of interest. The regrid works in two steps: mapping step which assigns to each cell of a mesh a set of its neighboring cells and interpolation step which estimates the data on each cell by combining the data from its neighbors. The common method to specify a cell neighborhood is the stencil string which is originally defined only for structured meshes, e.g., five-point stencil. The stencil was later generalized to express neighborhood on unstructured meshes. A stencil w.r.t. an unstructured mesh consists of a sequence of digits representing the dimensions of neighboring cells of a cell. For instance, the stencil 010 w.r.t. a mesh means any calculation for a vertex needs to have access to all the adjacent vertices (i.e., vertices sharing an edge with the vertex of interest). The stencil uses hard coded dimensions and thus contains no topological abstraction. Moreover, it is not obvious whether the result is the union of elements visited in each intermediate layer (hull) or the elements only in the last layer (halo). In addition, it is not possible to filter intermediate cells using predicates. Finally, existing mesh libraries (e.g., GrAL and GridFields) which accommodate the stencil concept do not provide a generic implementation, i.e., a specific Python or C++ APIs needs to be implemented for each stencil. We propose a neighborhood expression which uses the topological relationships (i.e., boundary, co-boundary, and adjacencies) to express arbitrary cell neighborhood. The expression contains any number of the topological relationships w.r.t. to a mesh and a cell as initial context of the neighborhood

  8. Mesh Plug Repair of Inguinal Hernia; Single Surgeon Experience

    Directory of Open Access Journals (Sweden)

    Ahmet Serdar Karaca


    Full Text Available Aim: Mesh repair of inguinal hernia repairs are shown to be an effective and reliable method. In this study, a single surgeon%u2019s experience with plug-mesh method performs inguinal hernia repair have been reported. Material and Method: 587 patients with plug-mesh repair of inguinal hernia, preoperative age, body / mass index, comorbid disease were recorded in terms of form. All of the patients during the preoperative and postoperative hernia classification of information, duration of operation, antibiotics, perioperative complications, and later, the early and late postoperative complications, infection, recurrence rates and return to normal daily activity, verbal pain scales in terms of time and postoperative pain were evaluated. Added to this form of long-term pain ones. The presence of wound infection was assessed by the presence of purulent discharge from the incision. Visual analog scale pain status of the patients was measured. Results: 587 patients underwent repair of primary inguinal hernia mesh plug. One of the patients, 439 (74% of them have adapted follow-ups. Patients%u2019 ages ranged from 18-86. Was calculated as the mean of 47±18:07. Follow-up period of the patients was found to be a minimum of 3 months, maximum 55 months. Found an average of 28.2±13.4 months. Mean duration of surgery was 35.07±4.00 min (min:22mn-max:52mn, respectively. When complication rates of patients with recurrence in 2 patients (0.5%, hematoma development (1.4% in 6 patients, the development of infection in 11 patients (2.5% and long-term groin pain in 4 patients (0.9% appeared. Discussion: In our experience, the plug-mesh repair of primary inguinal hernia repair safe, effective low recurrence and complication rates can be used.

  9. Highly scalable multichannel mesh electronics for stable chronic brain electrophysiology. (United States)

    Fu, Tian-Ming; Hong, Guosong; Viveros, Robert D; Zhou, Tao; Lieber, Charles M


    Implantable electrical probes have led to advances in neuroscience, brain-machine interfaces, and treatment of neurological diseases, yet they remain limited in several key aspects. Ideally, an electrical probe should be capable of recording from large numbers of neurons across multiple local circuits and, importantly, allow stable tracking of the evolution of these neurons over the entire course of study. Silicon probes based on microfabrication can yield large-scale, high-density recording but face challenges of chronic gliosis and instability due to mechanical and structural mismatch with the brain. Ultraflexible mesh electronics, on the other hand, have demonstrated negligible chronic immune response and stable long-term brain monitoring at single-neuron level, although, to date, it has been limited to 16 channels. Here, we present a scalable scheme for highly multiplexed mesh electronics probes to bridge the gap between scalability and flexibility, where 32 to 128 channels per probe were implemented while the crucial brain-like structure and mechanics were maintained. Combining this mesh design with multisite injection, we demonstrate stable 128-channel local field potential and single-unit recordings from multiple brain regions in awake restrained mice over 4 mo. In addition, the newly integrated mesh is used to validate stable chronic recordings in freely behaving mice. This scalable scheme for mesh electronics together with demonstrated long-term stability represent important progress toward the realization of ideal implantable electrical probes allowing for mapping and tracking single-neuron level circuit changes associated with learning, aging, and neurodegenerative diseases. Copyright © 2017 the Author(s). Published by PNAS.

  10. Design and implementation of a topology control scheme for wireless mesh networks

    CSIR Research Space (South Africa)

    Mudali, P


    Full Text Available The Wireless Mesh Network (WMN) backbone is usually comprised of stationary nodes but the transient nature of wireless links results in changing network topologies. Topology Control (TC) aims to preserve network connectivity in ad hoc and mesh...

  11. Teaching the transrectus sheath preperiotneal mesh repair: TREPP in 9 steps

    NARCIS (Netherlands)

    Akkersdijk, W.L.; Andeweg, C.S.; Bokkerink, W.J.V.; Lange, J.F.; Laarhoven, C.J.H.M. van; Koning, G.G.


    BACKGROUND: The preperitoneal mesh position seems preferable to reduce the number of patients with postoperative chronic pain after inguinal hernia surgery. The transrectus sheath preperitoneal mesh repair (TREPP) is gaining popularity. Teaching a new technique requires a standardized approach to

  12. Cell-vertex discretization of shallow water equations on mixed unstructured meshes (United States)

    Danilov, Sergey; Androsov, Alexey


    Finite-volume discretizations can be formulated on unstructured meshes composed of different polygons. A staggered cell-vertex finite-volume discretization, keeping the velocity degrees of freedom on cell centroids and scalar degrees of freedom on vertices, presents one possible choice. Its performance is analyzed on mixed meshes composed of triangles and quads. Although triangular meshes are most flexible geometrically, quads are more efficient numerically and do not support spurious inertial modes of the triangular cell-vertex discretization. Mixed meshes composed of triangles and quads combine benefits of both. In particular, triangular transitional zones can be used to join quadrilateral meshes of differing resolution, i. e., to provide smooth nesting of a fine mesh into a coarse one. Based on a set of examples involving shallow water equations it is shown that mixed meshes offer a viable approach provided some background biharmonic viscosity (or the biharmonic filter) is used to stabilize the triangular part of the mesh.

  13. Adaptive Mesh Iteration Method for Trajectory Optimization Based on Hermite-Pseudospectral Direct Transcription

    Directory of Open Access Journals (Sweden)

    Humin Lei


    Full Text Available An adaptive mesh iteration method based on Hermite-Pseudospectral is described for trajectory optimization. The method uses the Legendre-Gauss-Lobatto points as interpolation points; then the state equations are approximated by Hermite interpolating polynomials. The method allows for changes in both number of mesh points and the number of mesh intervals and produces significantly smaller mesh sizes with a higher accuracy tolerance solution. The derived relative error estimate is then used to trade the number of mesh points with the number of mesh intervals. The adaptive mesh iteration method is applied successfully to the examples of trajectory optimization of Maneuverable Reentry Research Vehicle, and the simulation experiment results show that the adaptive mesh iteration method has many advantages.

  14. Polypropylene meshes to prevent abdominal herniation. Can stable coatings prevent adhesions in the long term?

    NARCIS (Netherlands)

    Emans, Pieter J.; Schreinemacher, Marc H. F.; Gijbels, Marion J. J.; Beets, Geerard L.; Greve, Jan-Willem M.; Koole, Leo H.; Bouvy, Nicole D.


    Abdominal surgery is associated with a significant risk for incisional herniation. Hernia repair is routinely performed by implantation of synthetic meshes. Such meshes may cause serious adhesions between the implanted material and organs leading to intestinal obstruction or enterocutaneous

  15. Conforming to interface structured adaptive mesh refinement: 3D algorithm and implementation (United States)

    Nagarajan, Anand; Soghrati, Soheil


    A new non-iterative mesh generation algorithm named conforming to interface structured adaptive mesh refinement (CISAMR) is introduced for creating 3D finite element models of problems with complex geometries. CISAMR transforms a structured mesh composed of tetrahedral elements into a conforming mesh with low element aspect ratios. The construction of the mesh begins with the structured adaptive mesh refinement of elements in the vicinity of material interfaces. An r-adaptivity algorithm is then employed to relocate selected nodes of nonconforming elements, followed by face-swapping a small fraction of them to eliminate tetrahedrons with high aspect ratios. The final conforming mesh is constructed by sub-tetrahedralizing remaining nonconforming elements, as well as tetrahedrons with hanging nodes. In addition to studying the convergence and analyzing element-wise errors in meshes generated using CISAMR, several example problems are presented to show the ability of this method for modeling 3D problems with intricate morphologies.

  16. Surgical ethics: surgical virtue and more. (United States)

    Vercler, Christian J


    The encounter between a patient and her surgeon is unique for several reasons. The surgeon inflicts pain upon a patient for the patient's own good. An operative intervention is irreducibly personal, such that the decisions about and performance of operations are inseparable from the idiosyncrasies of the individual surgeon. Furthermore, there is a chasm of knowledge between the patient and surgeon that is difficult to cross. Hence, training in the discipline of surgery includes the inculcation of certain virtues and practices to safeguard against abuses of this relationship and to make sure that the best interests of the patient are prioritized. The stories in this issue are evidence that in contemporary practice this is not quite enough, as surgeons reflect on instances they felt were ethically challenging. Common themes include the difficulty in communicating surgical uncertainty, patient-surgeon relationships, ethical issues in surgical training, and the impact of the technological imperative on caring for dying patients.

  17. Simple and surgical exodontia. (United States)

    DeBowes, Linda J


    Preemptive and postoperative pain management is part of patient care when performing extractions. Simple extractions can become complicated when tooth roots are fractured. Adequate lighting,magnification, and surgical techniques are important when per-forming surgical (complicated) extractions. Radiographs should be taken before extractions and also during the procedure to assist with difficult extractions. Adequate flap design and bone removal are necessary when performing surgical extractions. Complications, including ocular trauma, jaw fracture, and soft tissue trauma, are avoided or minimized with proper patient selection and technique.

  18. Comparison of post-operative wound infection after inguinal hernia repair with polypropylene mesh and polyester mesh

    International Nuclear Information System (INIS)

    Mughal, M.A.; Ahmed, M.; Sajid, M.T.; Mustafa, Q.U.A.; Shukr, I.; Ahsan, J.


    Objective: To compare post operative wound infection frequency after inguinal hernia repair with polypropylene and polyester mesh using standard Lichtenstein hernioplasty technique. Study Design: Randomized controlled trial. Place and Duration: This study was conducted at general surgery department CMH/MH Rawalpindi from 8th April 2007 to 1st Jan 2008 over a period of 09 months. Patients and Materials: Sixty patients received through outpatient department with diagnosis of inguinal hernia satisfying inclusion/exclusion criteria were included. Patients were divided into two groups randomly. Group 1 included those patients in whom polypropylene mesh was used while group II patients were implanted with polyester mesh. Demographic as well as data concerning post operative wound infection was collected and analyzed. Results: Fifty seven patients (95%) were males while remaining (05%) were females. Mean age in group I was 41.17+-9.99 years while in group II was 41.47+-9.79 years (p=0.907). One patient (3.3%) in each group developed wound infection diagnosed by clinical evidence of pain at wound site, redness, induration and purulent discharge. Conclusion: There is no difference in post operative wound infection rate after inguinal Lichtenstein hernioplasty using either polypropylene or polyester mesh. (author)

  19. Introducing a distributed unstructured mesh into gyrokinetic particle-in-cell code, XGC (United States)

    Yoon, Eisung; Shephard, Mark; Seol, E. Seegyoung; Kalyanaraman, Kaushik


    XGC has shown good scalability for large leadership supercomputers. The current production version uses a copy of the entire unstructured finite element mesh on every MPI rank. Although an obvious scalability issue if the mesh sizes are to be dramatically increased, the current approach is also not optimal with respect to data locality of particles and mesh information. To address these issues we have initiated the development of a distributed mesh PIC method. This approach directly addresses the base scalability issue with respect to mesh size and, through the use of a mesh entity centric view of the particle mesh relationship, provides opportunities to address data locality needs of many core and GPU supported heterogeneous systems. The parallel mesh PIC capabilities are being built on the Parallel Unstructured Mesh Infrastructure (PUMI). The presentation will first overview the form of mesh distribution used and indicate the structures and functions used to support the mesh, the particles and their interaction. Attention will then focus on the node-level optimizations being carried out to ensure performant operation of all PIC operations on the distributed mesh. Partnership for Edge Physics Simulation (EPSI) Grant No. DE-SC0008449 and Center for Extended Magnetohydrodynamic Modeling (CEMM) Grant No. DE-SC0006618.

  20. Degradation of mesh coatings and intraperitoneal adhesion formation in an experimental model

    NARCIS (Netherlands)

    Schreinemacher, M. H. F.; Emans, P. J.; Gijbels, M. J. J.; Greve, J.-W. M.; Beets, G. L.; Bouvy, N. D.


    In laparoscopic ventral hernia repair a mesh is placed in direct contact with the viscera, often leading to substantial adhesions. In this experimental study the ability of different coated and uncoated meshes to attenuate adhesion formation was examined. Six commercially available meshes were

  1. Ambulatory Surgical Measures - Facility (United States)

    U.S. Department of Health & Human Services — The Ambulatory Surgical Center Quality Reporting (ASCQR) Program seeks to make care safer and more efficient through quality reporting. ASCs eligible for this...

  2. Ambulatory Surgical Measures - State (United States)

    U.S. Department of Health & Human Services — The Ambulatory Surgical Center Quality Reporting (ASCQR) Program seeks to make care safer and more efficient through quality reporting. ASCs eligible for this...

  3. Surgical Treatments for Fibroids (United States)

    ... NICHD Research Information Find a Study More Information Preeclampsia and Eclampsia About NICHD Research Information Find a ... Treatments Share Facebook Twitter Pinterest Email Print Surgical Treatments for Fibroids If you have moderate or severe ...

  4. Ambulatory Surgical Measures - National (United States)

    U.S. Department of Health & Human Services — The Ambulatory Surgical Center Quality Reporting (ASCQR) Program seeks to make care safer and more efficient through quality reporting. ASCs eligible for this...

  5. [Surgical treatment of ulcer]. (United States)

    Ungeheuer, E; Schröder, D; Lüders, K


    The standard of today in surgical treatment of the duodenal and gastric ulcer in Germany is shown. Positive and negative aspects of the different methods are discussed. Special technics are recommended for the different types of gastroduodenal ulcera.

  6. Disruptive visions: surgical education. (United States)

    Satava, R M


    Technological change, decreased financial support for medical education, and social oversight (in the form of the "To Err Is Human" report, HIPPA, and reduced work hours) are forcing a rethinking of the traditional model of surgical education to improve patient safety. New approaches to evaluating surgical competence, such as objective assessment, in combination with new technologies, such as the Internet and surgical simulators, provide the tools to effect a revolution in surgical education and training. Competency based upon quantifiable criteria measures must replace the traditional subjective assessment. The implementation requires accurately defining the elements of training, establishing new quantifiable metrics, stringently measuring performance against criterion, and reporting outcomes throughout the career of a surgeon.

  7. Surgical Critical Care Initiative (United States)

    Federal Laboratory Consortium — The Surgical Critical Care Initiative (SC2i) is a USU research program established in October 2013 to develop, translate, and validate biology-driven critical care....

  8. Video games and surgical ability: a literature review. (United States)

    Lynch, Jeremy; Aughwane, Paul; Hammond, Toby M


    Surgical training is rapidly evolving because of reduced training hours and the reduction of training opportunities due to patient safety concerns. There is a popular conception that video game usage might be linked to improved operating ability especially those techniques involving endoscopic modalities. If true this might suggest future directions for training. A search was made of the MEDLINE databases for the MeSH term, "Video Games," combined with the terms "Surgical Procedures, Operative," "Endoscopy," "Robotics," "Education," "Learning," "Simulators," "Computer Simulation," "Psychomotor Performance," and "Surgery, Computer-Assisted,"encompassing all journal articles before November 2009. References of articles were searched for further studies. Twelve relevant journal articles were discovered. Video game usage has been studied in relationship to laparoscopic, gastrointestinal endoscopic, endovascular, and robotic surgery. Video game users acquire endoscopic but not robotic techniques quicker, and training on video games appears to improve performance. Copyright (c) 2010 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  9. Laparoscopic adrenalectomy: Surgical techniques

    Directory of Open Access Journals (Sweden)

    Matthew J Mellon


    Full Text Available Since its first description in 1992, laparoscopic adrenalectomy has become the gold standard for the surgical treatment of most adrenal conditions. The benefits of a minimally invasive approach to adrenal resection such as decreased hospital stay, shorter recovery time and improved patient satisfaction are widely accepted. However, as this procedure becomes more widespread, critical steps of the operation must be maintained to ensure expected outcomes and success. This article reviews the surgical techniques for the laparoscopic adrenalectomy.

  10. The cutting-edge training modalities and educational platforms for accredited surgical training: A systematic review. (United States)

    Forgione, Antonello; Guraya, Salman Y


    Historically, operating room (OR) has always been considered as a stand-alone trusted platform for surgical education and training. However, concerns about financial constraints, quality control, and patient safety have urged the surgical educators to develop more cost-effective, surgical educational platforms that can be employed outside the OR. Furthermore, trained surgeons need to regularly update their surgical skills to keep abreast with the emerging surgical technologies. This research aimed to explore the value of currently available modern surgical tools that can be used outside the OR and also elaborates the existing laparoscopic surgical training programs in world-class centers across the globe with a view to formulate a blended and unified structured surgical training program. Several data sources were searched using MeSH terms "Laparoscopic surgery" and "Surgical training" and "Surgical curriculum" and "fundamentals of endoscopic surgery" and "fundamentals of laparoscopic surgery" and "Telementoring" and "Box trainer." The eligibility criteria used in data extraction searched for original and review articles and by excluding the editorial articles, short communications, conference proceedings, personal view, and commentaries. Data synthesis and data analysis were done by reviewing the initially retrieved 211 articles. Irrelevant and duplicate and redundant articles were excluded from the study. Finally, 12 articles were selected for this systematic review. Data results showed that a myriad of cutting-edge technical innovations have provided modern surgical training tools such as the simulation-based mechanical and virtual reality simulators, animal and cadaveric labs, telementoring, telerobotic-assisted surgery, and video games. Surgical simulators allow the trainees to acquire surgical skills in a tension-free environment without supervision or time constraints. The existing world-renowned surgical training centers employ various clusters of training

  11. Laparoscopic incisional hernia repair: Polyester versus Polytetraflouroethylene mesh

    Directory of Open Access Journals (Sweden)

    Adil Bangash


    Full Text Available Aims and Objectives: To compare the frequency of complications of laparoscopic repair of incisional hernia between polyester and Polytetraflouroethylene meshes. Materials and Methods: This study was conducted as part of an Interventional multicentre trial at the Rehman Medical Institute Peshawar, Peshawar Institute of Medical Sciences and Pakistan Institute of Medical Science Islamabad from the 1 st of October, 2008 till 30 th September, 2011. The frequency of complications was calculated as the measure of comparing two commercially available meshes for the laparoscopic repair of incisional hernia using the Intrperitoneal placement of mesh (IPOM technique. These patients were admitted via the out-patient department and their demographic data was collected on a proforma. The size of the defect was evaluated clinically or radiologically and if >10cm were excluded from the study. Forty five patients were alternately placed in either group and group I comprised patients with a ventral hernia that was repaired with composite polyester mesh (Parietex R whereas the other group was also repaired laparoscopically but repaired with a Polytetraflouroethylene (Dual R mesh. All data was collected on the individual proforma of each patient and was loaded on the SPSS R version 13.0. Results: The BMI (body mass index in both groups was similar ( P = 1.41. The mean hospital stay was higher in the Polytetraflouroethylene (PTFE mesh group but the values were not significant ( P = 1.12. No peri-operative death was observed in either group. Five patients (11.11% from group I were re-admitted with varying complaints and were diagnosed as having sub-acute intestinal obstruction ( P = 0.04. A higher but insignificant recurrence rate was observed in the polyester group over a one year period of follow up. Four patients (8.8% that were diagnosed with recurrences in group I. Instead the PTFE group had a lower recurrence ( P = 0.91. Conclusion: The frequency of recurrence

  12. Partial orbital rim resection, mesh skin expansion, and second intention healing combined with enucleation or exenteration for extensive periocular tumors in horses. (United States)

    Beard, W L; Wilkie, D A


    Ocular and periorbital sarcoids and squamous cell carcinoma are common in equine practice. Extensive involvement of periorbital tissues often necessitates removal of the globe if the function of the eyelids can not be maintained with tumor removal alone. This report describes a modification of the standard enucleation or exenteration technique for cases in which there is insufficient skin to achieve primary closure following complete surgical excision. The caudal portion of the dorsal orbital rim is protuberant; partial excision with an osteotome facilitates skin closure by decreasing the size of the wound. Mesh expansion of skin via multiple rows or parallel stab incisions can also be used as an adjunct to facilitate closure. Four horses underwent enucleation or exenteration using the orbital rim resection and mesh skin expansion techniques for extensive periocular tumors that were unresponsive to prior treatments. Follow-up intervals ranged from 6 to 42 months and no horses had tumor regrowth.

  13. Comparison of the fracture resistances of glass fiber mesh- and metal mesh-reinforced maxillary complete denture under dynamic fatigue loading (United States)


    PURPOSE The aim of this study was to investigate the effect of reinforcing materials on the fracture resistances of glass fiber mesh- and Cr–Co metal mesh-reinforced maxillary complete dentures under fatigue loading. MATERIALS AND METHODS Glass fiber mesh- and Cr–Co mesh-reinforced maxillary complete dentures were fabricated using silicone molds and acrylic resin. A control group was prepared with no reinforcement (n = 15 per group). After fatigue loading was applied using a chewing simulator, fracture resistance was measured by a universal testing machine. The fracture patterns were analyzed and the fractured surfaces were observed by scanning electron microscopy. RESULTS After cyclic loading, none of the dentures showed cracks or fractures. During fracture resistance testing, all unreinforced dentures experienced complete fracture. The mesh-reinforced dentures primarily showed posterior framework fracture. Deformation of the all-metal framework caused the metal mesh-reinforced denture to exhibit the highest fracture resistance, followed by the glass fiber mesh-reinforced denture (Pdenture primarily maintained its original shape with unbroken fibers. River line pattern of the control group, dimples and interdendritic fractures of the metal mesh group, and radial fracture lines of the glass fiber group were observed on the fractured surfaces. CONCLUSION The glass fiber mesh-reinforced denture exhibits a fracture resistance higher than that of the unreinforced denture, but lower than that of the metal mesh-reinforced denture because of the deformation of the metal mesh. The glass fiber mesh-reinforced denture maintains its shape even after fracture, indicating the possibility of easier repair. PMID:28243388

  14. Post surgical complications from students' large animal surgical ...

    African Journals Online (AJOL)

    A retrospective study of post surgical complications was conducted on records of students' Large Animal Surgical Laboratories in the Faculty of Veterinary Medicine (F.V.M.), Ahmadu Bello University (A.B.U), Zaria from 1989 to 1993. Three hundred and eleven surgical complications were recorded from five surgical ...

  15. Preclinical evaluation of the effect of the combined use of the Ethicon Securestrap® Open Absorbable Strap Fixation Device and Ethicon Physiomesh™ Open Flexible Composite Mesh Device on surgeon stress during ventral hernia repair

    Directory of Open Access Journals (Sweden)

    Sutton N


    Full Text Available Nadia Sutton,1 Melinda H MacDonald,2 John Lombard,1 Bodgan Ilie,3 Piet Hinoul,4 Douglas A Granger5,6 1Global Health Economics and Market Access, Johnson & Johnson Medical Devices, New Brunswick, NJ, USA; 2Preclinical Center of Excellence, Johnson & Johnson Medical Devices Companies, Somerville, NJ, USA; 3Biostatistics, Ethicon, Somerville, NJ, USA; 4Medical Affairs, Ethicon, Somerville, NJ, USA; 5Institute for Interdisciplinary Salivary Bioscience Research (IISBR, University of California at Irvine, Irvine, CA, USA; 6Johns Hopkins University School of Nursing, Bloomberg School of Public Health, and School of Medicine, Baltimore, MD, USA Aim: To evaluate whether performing ventral hernia repairs using the Ethicon Physiomesh™ Open Flexible Composite Mesh Device in conjunction with the Ethicon Securestrap® Open Absorbable Strap Fixation Device reduces surgical time and surgeon stress levels, compared with traditional surgical repair methods. Methods: To repair a simulated ventral incisional hernia, two surgeries were performed by eight experienced surgeons using a live porcine model. One procedure involved traditional suture methods and a flat mesh, and the other procedure involved a mechanical fixation device and a skirted flexible composite mesh. A Surgery Task Load Index questionnaire was administered before and after the procedure to establish the surgeons’ perceived stress levels, and saliva samples were collected before, during, and after the surgical procedures to assess the biologically expressed stress (cortisol and salivary alpha amylase levels. Results: For mechanical fixation using the Ethicon Physiomesh Open Flexible Composite Mesh Device in conjunction with the Ethicon Securestrap Open Absorbable Strap Fixation Device, surgeons reported a 46.2% reduction in perceived workload stress. There was also a lower physiological reactivity to the intraoperative experience and the total surgical procedure time was reduced by 60

  16. Laser patterned carbon–polyethylene mesh electrodes for wound diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Phair, Jolene; Joshi, Mayank; Benson, John; McDonald, Damian; Davis, James, E-mail:


    Carbon loaded polyethylene films were selected as the base substrate for a mechanically flexible and conductive sensing material for use wound monitoring technologies. The films were processed using laser ablation of the surface to increase the effective surface area of the electrode and then subject to an oxidative electrochemical etch to improve the electron transfer kinetics. The surface morphology of the resulting films was analysed and the electrode performance in relation to monitoring uric acid, a key wound biomarker, was optimized. A prototype smart bandage was designed, based on interfacing the mesh to a portable potentiostat, and the response to urate and potential interferences assessed. - Highlights: • Innovative use of a carbon–polyethylene mesh for wound sensing applications. • Electroanalytical characterisation of a mechanically flexible conductive film. • Design and preliminary characterisation of an integrated smart bandage.

  17. A mesh-free algorithm for ROF model (United States)

    Khan, Mushtaq Ahmad; Chen, Wen; Ullah, Asmat; Fu, Zhuojia


    The total variation (TV) denoising method is a PDE-based technique that preserves the edges well but has undesirable staircase effect in some cases, namely, the translation of smooth regions (ramps) into piecewise constant regions (stairs). This paper introduces a novel mesh-free approach using TV (ROF model) regularization and radial basis function (RBF) for the numerical approximation of TV-based model to remove the additive noise from the measurements. This approach is structured on local collocation and multiquadric radial basis function. These features enable this strategy not only to eliminate noise from images and preserve the edges but also has the advantage to minimize the staircase effect substantially from real and artificial images which cause the image to look blocky. Experimental results demonstrate that the proposed mesh-free approach is robust and performs well in visual improvement as well as peak signal-to-noise ratio compared with the recent partial differential equation (PDE)-based traditional methods.

  18. Smart-Home Architecture Based on Bluetooth mesh Technology (United States)

    Wan, Qing; Liu, Jianghua


    This paper describes the smart home network system based on Nordic nrf52832 device. Nrf52832 is new generation RF SOC device focus on sensor monitor and low power Bluetooth connection applications. In this smart home system, we set up a self-organizing network system which consists of one control node and a lot of monitor nodes. The control node manages the whole network works; the monitor nodes collect the sensor information such as light intensity, temperature, humidity, PM2.5, etc. Then update to the control node by Bluetooth mesh network. The design results show that the Bluetooth mesh wireless network system is flexible and construction cost is low, which is suitable for the communication characteristics of a smart home network. We believe it will be wildly used in the future.

  19. Three-dimensional data visualization using DSP meshes (United States)

    Liow, Yuh-Tay; Civanlar, Mehmet R.; Dzik, Steven C.


    This paper presents a parallel scheme for three dimensional data visualization at interactive rates. The scheme is particularly suitable for multiprocessor systems with distributed frame buffers and is currently implemented on an AT&T Pixel Machine, a parallel computer based on mesh connected digital signal processors with a distributed frame buffer. Nearly linear performance increase with the number of processors in the mesh is obtained by partitioning the original three dimensional data into sub-blocks and processing each sub-block in parallel. The approach is very flexible in implementing a variety of visualization techniques, such as volume compositing (translucent models), binary-class and percentage mixtures and surface based volume rendering.

  20. Secure Multicast Routing Algorithm for Wireless Mesh Networks

    Directory of Open Access Journals (Sweden)

    Rakesh Matam


    Full Text Available Multicast is an indispensable communication technique in wireless mesh network (WMN. Many applications in WMN including multicast TV, audio and video conferencing, and multiplayer social gaming use multicast transmission. On the other hand, security in multicast transmissions is crucial, without which the network services are significantly disrupted. Existing secure routing protocols that address different active attacks are still vulnerable due to subtle nature of flaws in protocol design. Moreover, existing secure routing protocols assume that adversarial nodes cannot share an out-of-band communication channel which rules out the possibility of wormhole attack. In this paper, we propose SEMRAW (SEcure Multicast Routing Algorithm for Wireless mesh network that is resistant against all known active threats including wormhole attack. SEMRAW employs digital signatures to prevent a malicious node from gaining illegitimate access to the message contents. Security of SEMRAW is evaluated using the simulation paradigm approach.