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Sample records for surgical titanium mesh

  1. Hernia Surgical Mesh Implants

    Science.gov (United States)

    ... Prosthetics Hernia Surgical Mesh Implants Hernia Surgical Mesh Implants Share Tweet Linkedin Pin it More sharing options ... majority of tissue used to produce these mesh implants are from a pig (porcine) or cow (bovine) ...

  2. Urogynecologic Surgical Mesh Implants

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    ... Prosthetics Urogynecologic Surgical Mesh Implants Urogynecologic Surgical Mesh Implants Share Tweet Linkedin Pin it More sharing options ... majority of tissue used to produce these mesh implants are from a pig (porcine) or cow (bovine). ...

  3. Adaptive mesh refinement in titanium

    Energy Technology Data Exchange (ETDEWEB)

    Colella, Phillip; Wen, Tong

    2005-01-21

    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.

  4. The application of computer-aided designated titanium mesh in repairing skull defects

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    Lei ZHANG

    2015-01-01

    Full Text Available Objective To explore the clinical value of repairing skull defects with titanium alloy-mesh of computer-aided design.  Methods A retrospective analysis was done on clinical data of 86 cases with skull defects who underwent repairing using titanium mesh with two-dimensional or three-dimensional computer-aided design.  Results All the incisions achieved primary healing other than one case conducting reoperation due to exposed titanium mesh. Two cases got subcutaneous exudate, one obtained painful mastication and one experienced proliferation of scalp scar.  Conclusions With the computer-aided designated titanium mesh, relevant operation can resume the original state to maximum extent, lower surgical risk, decrease post-operational complications and then obtain satisfying clinical effect. DOI: 10.3969/j.issn.1672-6731.2015.01.015

  5. Histological assessment of titanium and polypropylene fiber mesh implantation with and without fibrin tissue glue

    NARCIS (Netherlands)

    Hallers, E.J.O. ten; Jansen, J.A.; Marres, H.A.M.; Rakhorst, G.; Verkerke, G.J.

    2007-01-01

    Polypropylene (PP) and titanium (Ti) meshes are well-known surgical implants that provoke a relative low foreign body reaction. Firm stabilization of the implant is important to prevent migration and subsequent failure of the operation. Fibrin tissue glues are commercially available adhesives and ar

  6. Palatomaxillary reconstruction with titanium mesh and radial forearm flap.

    Science.gov (United States)

    Sun, Guowen; Yang, Xudong; Tang, Enyi; Wen, Jianmin; Lu, Mingxing; Hu, Qingang

    2009-10-01

    The purpose of this study was to assess the treatment and prognosis of the palatomaxillary reconstruction with titanium mesh and the free radial forearm flap. This is a retrospective study of 19 patients with palatomaxillary defects who underwent immediate reconstruction using titanium mesh and a radial forearm flap during the 4-year period from 2004 to 2008. Intraoperatively, the titanium mesh was fixed to the residual bones for the reconstruction of hard-tissue defect after the tumor resection; then the free radial forearm flap was harvested to repair the soft-tissue defect, serving as the intraoral lining and titanium mesh covering. Postoperative esthetic appearance and function were followed-up. All of the patients achieved a satisfactory facial appearance. The speech assessment was good, and the oronasal reflux did not occur in all patients. Only 3 patients had titanium mesh exposure during the follow-up period. The free radial forearm flap with folded titanium mesh is a reliable option for reconstruction of palatomaxillary defects. It is highly effective for swallowing and speech rehabilitation as well as esthetic reconstruction.

  7. Comminuted Frontal Sinus Fracture Reconstructed With Titanium Mesh.

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    Sakat, Muhammed Sedat; Kilic, Korhan; Altas, Enver; Gozeler, Mustafa Sitki; Ucuncu, Harun

    2016-03-01

    Frontal sinus fractures (FSF) are relatively uncommon maxillofacial injuries. The most common cause of FSF is motor vehicle accidents with 62% percentage. Management of FSF depends on type of fracture, associated injuries, and involvement of naso-frontal duct. In this report, the authors presented a patient with comminuted fracture of anterior wall of frontal sinus reconstructed with titanium mesh. A 40-year-old man presented with depression of the frontal bone, facial pain, and epistaxis consisting of a motor vehicle accident. Computerized tomography scan revealed multiple comminuted fractures of anterior wall of frontal sinus and fractures of left orbital medial and superior walls. Titanium mesh was used for reconstruction. Postoperative course was uneventful. The titanium mesh, which is easy to handle with no complications, may provide excellent frontal contour after comminuted anterior wall fractures.

  8. Individual prefabricated titanium implants and titanium mesh in skull base reconstructive surgery. A report of cases.

    Science.gov (United States)

    Schipper, J; Ridder, G J; Spetzger, U; Teszler, C B; Fradis, M; Maier, W

    2004-05-01

    Titanium implants can be shaped by traditional hand forming, press shaping, modular construction by welding, construction on full-size models shaped from CT coordinates and, most recently, by computer-assisted design and computer-assisted manufacturing (CAD/CAM) that consist in the direct prefabrication of individual implants by milling them out of a solid block of titanium. The aim of our study was to present a set of preliminary cases of an ongoing program of reconstructive procedures of the skull base using titanium implants. The subjects underwent ablative procedures of the skull base with reconstruction either by titanium mesh or individual prefabricated CAD/CAM implants. Six patients have been operated on successfully since 2000: two received prefabricated CAD/CAM titanium plates and four others underwent reconstruction with titanium mesh. The stability of CAD/CAM plates is superior to that of mesh, thus it is more useful in reconstructing large lesions of the frontal skull base and the temporal and occipital bones. Titanium mesh was successfully used for defects smaller than 100 cm(2) or where selected viscerocranial defects are complicated in design and less reproducible by CAD/CAM. The intraoperative design, shaping and adjustment characteristic of titanium mesh can be dispensed with when CAD/CAM implants are used. The 3-D data set used in the CAD/CAM process also operates in the navigated simulation and planning of the ablation contours, the latter being of great assistance in establishing the optimal future defect. As a disadvantage, CAD/CAM technology is more expensive than titanium mesh, and the process is time-consuming as it is carried out in advance of surgery.

  9. Can titanium mesh influence local recurrence management after implant-based breast reconstruction?

    Science.gov (United States)

    Riggio, Egidio; Chifu, Camelia; Martelli, Gabriele; Ferraris, Cristina

    2015-01-01

    TiLOOP(®) Bra is a permanent titanium-coated polypropylene mesh currently used in post-mastectomy breast reconstruction with implants. This mesh is generally presented as inducing low-grade inflammatory reactions, but only few reports focused on its possible side effects. In the case described here, the use of the mesh led to minor clinical problems that needed to be clinically and surgically managed at the same time as a local relapse. A patient with high-grade ductal carcinoma in situ underwent primary surgery (nipple-sparing mastectomy and one-stage reconstruction using the TiLOOP(®) Bra mesh) and was subsequently referred for radiological and clinical investigation when various nodules became apparent during a follow-up physical examination. Prior to the histopathological proof, the diagnosis of local recurrence was complicated by the occurrence of an extensive granulomatous reaction in the fixation areas along with mild inflammatory changes scattered on the surface of the mesh. This case illustrates a side effect of titanium-coated permanent mesh in immediate implant-based reconstruction, i.e. the formation of granulomas in the inframammary fold, probably in the area where the mesh had been folded or fixed. We propose a safer technical approach to avoid the problem and a clinical management strategy for patients at high risk of local recurrence who develop granuloma-like nodules. A surgical technique is suggested to prevent granuloma formation. If, however, subcutaneous nodules that may be local recurrences do appear, they should not be interpreted by default as a granulomatous reaction, but should be fully investigated and possibly excised.

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

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    Gang-ge CHENG

    2013-09-01

    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.

  11. Electrical characteristic of the titanium mesh electrode for transcutaneous intrabody communication to monitor implantable artificial organs.

    Science.gov (United States)

    Okamoto, Eiji; Kikuchi, Sakiko; Mitamura, Yoshinori

    2016-09-01

    We have developed a tissue-inducing electrode using titanium mesh to obtain mechanically and electrically stable contact with the tissue for a new transcutaneous communication system using the human body as a conductive medium. In this study, we investigated the electrical properties of the titanium mesh electrode by measuring electrode-tissue interface resistance in vivo. The titanium mesh electrode (Hi-Lex Co., Zellez, Hyogo, Japan) consisted of titanium fibers (diameter of 50 μm), and it has an average pore size of 200 μm and 87 % porosity. The titanium mesh electrode has a diameter of 5 mm and thickness of 1.5 mm. Three titanium mesh electrodes were implanted separately into the dorsal region of the rat. We measured the electrode-electrode impedance using an LCR meter for 12 weeks, and we calculated the tissue resistivity and electrode-tissue interface resistance. The electrode-tissue interface resistance of the titanium mesh electrode decreased slightly until the third POD and then continuously increased to 75 Ω. The electrode-tissue interface resistance of the titanium mesh electrode is stable and it has lower electrode-tissue interface resistance than that of a titanium disk electrode. The extracted titanium mesh electrode after 12 weeks implantation was fixed in 10 % buffered formalin solution and stained with hematoxylin-eosin. Light microscopic observation showed that the titanium mesh electrode was filled with connective tissue, inflammatory cells and fibroblasts with some capillaries in the pores of the titanium mesh. The results indicate that the titanium mesh electrode is a promising electrode for the new transcutaneous communication system.

  12. Chest wall resection and reconstruction using titanium micromesh covered with Marlex mesh for metastatic follicular thyroid carcinoma: a case report

    Directory of Open Access Journals (Sweden)

    Suganuma Nobuyasu

    2009-06-01

    Full Text Available Abstract Introduction The distant metastases from differentiated thyroid carcinomas are often untreatable. In particular, bone metastasis is significantly related to poor prognosis since radioactive iodine therapy is generally less effective. Therefore, surgical resection is considered one of the treatments for patients with bone metastases. We report chest wall resection and reconstruction using titanium micromesh covered with polypropylene mesh (Marlex mesh for metastatic rib bones as a result of follicular thyroid carcinoma. Case presentation A 51-year-old man was referred to our institution with a painful chest wall tumor. He presented with a 15 × 10 cm bony swelling on the left chest wall and multiple small lung nodules from follicular thyroid carcinoma. Completion total thyroidectomy, chest wall resection and reconstruction using titanium micromesh covered with Marlex mesh were performed. There were no critical complications associated with surgical treatments and tumor pain disappeared during the postoperative period. Then, he received radioactive iodine therapy and the uptake of radioactive iodine was well observed in bilateral lung fields. Conclusion Reconstruction using titanium micromesh covered with Marlex mesh is possible for repairing the wide chest wall resection required for thyroid carcinoma metastasis. This technique would help to enhance treatment efficacy in the combination therapy of radioactive iodine and surgery in patients with large thyroid carcinoma metastasis in the chest wall.

  13. Dedifferentiated fat cells differentiate into osteoblasts in titanium fiber mesh.

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    Kishimoto, Naotaka; Momota, Yoshihiro; Hashimoto, Yoshiya; Ando, Kayoko; Omasa, Takeshi; Kotani, Junichiro

    2013-01-01

    Mature adipocyte-derived dedifferentiated fat (DFAT) cells rapidly differentiate into osteoblasts under three-dimensional culture conditions. However, it has not been demonstrated that DFAT cells can differentiate into osteoblasts in a rigid scaffold consisting of titanium fiber mesh (TFM). We examined the proliferation and osteogenic differentiation ability of DFAT cells using TFM as a scaffold. DFAT cells derived from rabbit subcutaneous fat were seeded into TFM and cultured in osteogenic medium containing dexamethasone, L-ascorbic acid 2-phosphate and β-glycerophosphate for 14 days. In scanning electron microscopy (SEM) analysis, well-spread cells covered the titanium fibers on day 3, and appeared to increase in number from day 3 to 7. Numerous globular accretions were found and almost completely covered the fibers on day 14. Cell proliferation, as measured by DNA content in the TFM, was significantly higher on day 7 compared with that of day 1. Osteocalcin and calcium content in the TFM were significantly higher on day 14 compared to those of days 1, 3, and 7, indicating DFAT cells differentiated into osteoblasts. We theorize that globular accretions observed in SEM analysis may be calcified matrix resulting from osteocalcin secreted by osteoblasts binding calcium contained in fetal bovine serum. In this study, we demonstrated that DFAT cells differentiate into osteoblasts and deposit mineralized matrices in TFM. Therefore, the combination of DFAT cells and TFM may be an attractive option for bone tissue engineering.

  14. Orbital wall reconstruction with titanium mesh: retrospective study of 24 patients.

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    Gabrielli, Mario Francisco; Monnazzi, Marcelo Silva; Passeri, Luis Augusto; Carvalho, Waldner Ricardo; Gabrielli, Marisa; Hochuli-Vieira, Eduardo

    2011-09-01

    The aim of this study was to evaluate the efficacy and safety of traumatic orbital defect reconstruction with titanium mesh. A retrospective study was made. Evaluations were made after a minimum postoperative follow-up of 12 months, looking for the main complications. Twenty-four patients were included in this evaluation; 19 were male (79.1%) and 5 (20.8%) were female. The main injury etiology was vehicle accidents (50%) followed by other causes. Fourteen patients (58.3%) presented orbital floor fractures, and 10 had more than one wall fractured (41.6%). Permanent infraorbital nerve hypoesthesia was observed in two patients (8.3%), enophthalmos occurred in five patients (20.8%), and exophthalmos was found in two patients (8.3%). Four patients (16.6%) still presented evidence of residual prolapsed intraorbital content, and one of those needed further surgical correction; sinusitis occurred in one patient (4.1%). Titanium mesh is a reliable option for orbital reconstruction, despite some complications found in this sample.

  15. Orbital Reconstruction: Patient-Specific Orbital Floor Reconstruction Using a Mirroring Technique and a Customized Titanium Mesh.

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    Tarsitano, Achille; Badiali, Giovanni; Pizzigallo, Angelo; Marchetti, Claudio

    2016-10-01

    Enophthalmos is a severe complication of primary reconstruction of orbital floor fractures. The goal of secondary reconstruction procedures is to restore symmetrical globe positions to recover function and aesthetics. The authors propose a new method of orbital floor reconstruction using a mirroring technique and a customized titanium mesh, printed using a direct metal laser-sintering method. This reconstructive protocol involves 4 steps: mirroring of the healthy orbit at the affected site, virtual design of a patient-specific orbital floor mesh, CAM procedures for direct laser-sintering of the customized titanium mesh, and surgical insertion of the device. Using a computed tomography data set, the normal, uninjured side of the craniofacial skeleton was reflected onto the contralateral injured side, and a reconstructive orbital floor mesh was designed virtually on the mirrored orbital bone surface. The solid-to-layer files of the mesh were then manufactured using direct metal laser sintering, which resolves the shaping and bending biases inherent in the indirect method. An intraoperative navigation system ensured accuracy of the entire procedure. Clinical outcomes were assessed using 3dMD photogrammetry and computed tomography data in 7 treated patients. The technique described here appears to be a viable method to correct complex orbital floor defects needing delayed reconstruction. This study represents the first step in the development of a wider experimental protocol for orbital floor reconstruction using computer-assisted design-computer-assisted manufacturing technology.

  16. Reconstruction of skull base defects in sphenoid wing dysplasia associated with neurofibromatosis I with titanium mesh.

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    Lotfy, Mohamed; Xu, Risheng; McGirt, Matthew; Sakr, Sameh; Ayoub, Basim; Bydon, Ali

    2010-12-01

    Sphenoid wing dysplasia occurs in 3-7% of patients with neurofibromatosis type 1 (NF1). The typical radiological features are partial or complete absence of the greater wing of the sphenoid. This condition is slowly progressive and may result in temporal lobe herniation into the orbital cavity, producing pulsating exophthalmos and gross facial deformity. Thus, reconstruction of the orbit is important for both cosmetic and functional reasons. Traditional surgical treatment of sphenoid dysplasia involves split bone grafting and repair of the anterior skull base defect. However, several reports have demonstrated complications of graft resorption and recurrence of proptosis and pulsating exopthalmos. In this case series, we present two patients suffering from pulsating exophthalmos due to sphenoid dysplasia. Radiological and MRI studies demonstrated orbital enlargement and complete absence of the greater wing of the sphenoid. Surgical management of these patients involved dural defect repair, and the use of titanium mesh in conjunction with bone graft to act as a barrier between the orbit and the middle cranial fossa. The mesh was fixed by fine screws. Proptosis improved markedly post-operatively and resolved within a few weeks. Ocular pulsation subsided and remained quiescent with at least 1-year follow-up.

  17. Customized Titanium Mesh for Repairing Cranial Defects: A Method With Comprehensive Evaluation.

    Science.gov (United States)

    Zhang, Jingjing; Long, Jianhong; Yang, Xinghua; Lei, Shaorong; Xiao, Muzhang; Fan, Pengju; Qi, Min; Tan, Wuyuan

    2015-11-01

    Titanium cranioplasty is one of the well-established and widely used techniques for repairing cranial defects. In this paper, we present an improved way to design and create titanium meshes with more evaluation process. Computed tomography scan data of patients were used to create three-dimensional virtual models. Implants were designed with NX ImageWare 13.2 (Siemens PLM Software, Plano, TX). Final titanium meshes were assessed by Geomagic Studio 12 (Geomagic, Inc., Morrisville, NC) and NX ImageWare 13.2.Titanium meshes were designed and applied to cranioplasty surgery on 8 patients. Postoperative results were evaluated by computed tomography scanning and further analyzed with rainbow difference tomography. All patients were satisfied with the outcome. With this method, surgeons, engineers, and patients work together to evaluate and edit implant design. Our method provides better communication and comprehensive evaluation, which result in a satisfying outcome.

  18. 颅骨修补术后钛网外露%Cranioplasty with titanium mesh exposure

    Institute of Scientific and Technical Information of China (English)

    张猛; 邵柏; 颜庆华; 丁兴进

    2014-01-01

    Objective To explore the reason , prevention and therapy of titanium mesh exposure after cranioplasty . Methods The reasons of titanium mesh exposure after cranioplasty were studied and some measures such as debridement , relaxation suture and rotation flap were taken correspondingly .Remove titanium mesh if necessary . Results Six patients with titanium mesh exposure were healing after therapy with four patients keeping titanium mesh and two removing it .One of the two patients repaired skull with the primary titanium mesh a year and a half later . Conclusion Much attention should be paid to the prevention of titanium mesh exposure after cranioplasty , measures should be taken for early treatment as soon as the complication occurs .%目的:探讨颅骨修补术后钛网外露的常见原因及治疗方法。方法分析颅骨修补术后钛网外露的原因并根据情况选择给予扩创、缺损皮瓣减张缝合、转移皮瓣缝合等手术,必要时取出修补材料。结果6例患者伤口均痊愈:其中4例保留钛网,2例取除钛网(其中1例半年后再次手术原钛网修复颅骨)。结论对行钛网颅骨修补患者应谨防钛网外露,发生后应及时治疗。

  19. Efficacy of a mesenchymal stem cell loaded surgical mesh for tendon repair in rats

    OpenAIRE

    Schon, Lew C.; Gill, Nicholas; Thorpe, Margaret; Davis, Joel; Nadaud, Joshua; Kim, Jooyoung; Molligan, Jeremy; Zhang, Zijun

    2014-01-01

    Objectives The purpose of this study was to investigate the efficacy of a composite surgical mesh for delivery of mesenchymal stem cells (MSCs) in tendon repair. Methods The MSC-loaded mesh composed of a piece of conventional surgical mesh and a layer of scaffold, which supported MSC-embedded alginate gel. A 3-mm defect was surgically created at the Achilles tendon-gastrocnemius/soleus junction in 30 rats. The tendon defects were repaired with either 1) MSC-loaded mesh; or 2) surgical mesh on...

  20. Maxillary reconstruction with particulate bone graft and titanium mesh: a treatment option for large complex odontoma of the maxilla.

    Science.gov (United States)

    Utumi, Estevam Rubens; Cremonini, Caio Cesar; Pedron, Irineu Gregnanin; Zambon, Camila Eduarda; Cavalcanti, Marcelo Gusmão Paraíso; Ceccheti, Marcelo Minharro

    2011-07-01

    Odontomas are the most common type of odontogenic tumor and are generally asymptomatic. The purpose of this paper was to describe the case of a complex odontoma in a patient who had asymptomatic swelling in the central maxillary region, along with unerupted central and lateral incisors. In this case, surgical excision of the lesion was performed and an iliac bone graft was introduced into the defect area with a titanium mesh covering up the grafted harvesting bone. After 2 years of followup, no recurrence was identified. Patient followup is still in progress to evaluate bone graft resorption, and the patient awaits complete bone development. Oral rehabilitation with an osseointegrated titanium implant is expected in the future. An option of the large complex odontoma treatment is discussed.

  1. Evaluation of various seeding techniques for culturing osteogenic cells on titanium fiber mesh.

    NARCIS (Netherlands)

    Dolder, J. van den; Spauwen, P.H.M.; Jansen, J.A.

    2003-01-01

    The objective of the present study was to learn more about the effect of seeding and loading techniques on the osteogenic differentiation in vitro of rat bone marrow cells into titanium fiber mesh. This material was used as received or subjected to glow discharge treatment (RFGD). The seeding

  2. The influence of bone formation on anchoring percutaneous devices with titanium fibre mesh flanges.

    NARCIS (Netherlands)

    Shalabi, M.M.; Walboomers, X.F.; Jansen, J.A.

    2004-01-01

    For man-made percutaneous devices (PD), it is known that anchoring will improve the clinical success. Previously, our Department has designed PDs that use a sheet of titanium (Ti) fibre mesh for anchoring. In nature, a very successful natural PD occurs, namely the tooth. Teeth are anchored in the al

  3. Flow perfusion culture of marrow stromal osteoblasts in titanium fiber mesh.

    NARCIS (Netherlands)

    Dolder, J. van den; Bancroft, G.N.; Sikavitsas, V.I.; Spauwen, P.H.M.; Jansen, J.A.; Mikos, A.G.

    2003-01-01

    The objective of this study was to evaluate the effect of two cell culture techniques, static and flow perfusion, on the osteogenic expression of rat bone marrow cells seeded into titanium fiber mesh for a period up to 16 days. A cell suspension of rat bone marrow stromal osteoblasts (5 x 10(5) cell

  4. Osteoblast differentiation with titania and titania-silica-coated titanium fiber meshes.

    NARCIS (Netherlands)

    Meretoja, V.V.; Ruijter, A.E. de; Peltola, T.; Jansen, J.A.; Narhi, T.O.

    2005-01-01

    Two surface-reactive sol-gel coatings, namely titania (TiO2) and a mixture of titania and silica (TiSi), were applied to titanium fiber meshes. Differentiation of rat bone marrow stromal cells toward an osteogenic phenotype with coated and uncoated (cpTi) substrates was compared. The amount of DNA i

  5. Evaluation of various seeding techniques for culturing osteogenic cells on titanium fiber mesh.

    NARCIS (Netherlands)

    Dolder, J. van den; Spauwen, P.H.M.; Jansen, J.A.

    2003-01-01

    The objective of the present study was to learn more about the effect of seeding and loading techniques on the osteogenic differentiation in vitro of rat bone marrow cells into titanium fiber mesh. This material was used as received or subjected to glow discharge treatment (RFGD). The seeding method

  6. The Surgical Results of Onlay Mesh Repair for Incisional Hernia

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    Bülent Kaya

    2012-10-01

    Full Text Available Aim: İncisional hernia after abdominal surgery is an important problem. We aimed to evaluate the longterm recurrence rate as well as surgical complications in patients operated with onlay mesh repair technique for incisional hernia. Material and Method: We studied a serial of 139 patients retrospectively, operated due to incisional hernia in between January 2001 to November 2009 in Vakıf Gureba Training and Research Hospital General Surgery Department. The patient’s age, sex, location and size of the defect, operation findings, duration of hospitalization, early and late complications and recurrences were recorded. Result: There were 56 men and 83 women inour serial. The mean age was 55 (age range, 30-85 years. The most commonincisions that hernia had been developed were upper midline incision (51 patients and lower midline incision (37 patients. The size of the hernia defect was 0-5 cm in 118 patients , 6-10 cm in 5 patients 11-15 cm in 12 patients, and above 15 cm in 4 patients. The postoperative complications were wound infection in 22 patients, seroma in 12 patients. The mean duration of hospital stay was 4.53 (range 1-10 days. The recurrence was detected in 6 patients. Discussion: It seems to be that onlay mesh repair is safe and effective technique for incisional hernia repair.

  7. Surface orientation effects on bending properties of surgical mesh are independent of tensile properties.

    Science.gov (United States)

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

    2017-04-17

    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, 2017. © 2017 Wiley Periodicals, Inc.

  8. Randomized clinical trial of fibrin sealant versus titanium tacks for mesh fixation in laparoscopic umbilical hernia repair

    DEFF Research Database (Denmark)

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

    2011-01-01

    The use of tacks for mesh fixation may induce pain after surgery for ventral hernia. The aim of this study was to compare postoperative pain after laparoscopic ventral hernia repair (LVHR) with conventional mesh fixation using titanium tacks versus fibrin sealant (FS).......The use of tacks for mesh fixation may induce pain after surgery for ventral hernia. The aim of this study was to compare postoperative pain after laparoscopic ventral hernia repair (LVHR) with conventional mesh fixation using titanium tacks versus fibrin sealant (FS)....

  9. Biomechanical compatibility of surgical mesh and fascia being reinforced: dependence of experimental hernia defect repair results on anisotropic surgical mesh positioning.

    Science.gov (United States)

    Anurov, M V; Titkova, S M; Oettinger, A P

    2012-04-01

    We aimed to compare the effectiveness of experimental middle hernia defect repair in regard to the transverse and longitudinal positioning of anisotropic lightweight surgical mesh. The mechanical properties of fascial layers and surgical mesh DynaMesh(®)-PP Light were determined in two perpendicular directions under uniaxial tension. In 12 male Wistar rats, middle hernia defect was repaired by the sublay technique. In six animals, the mesh was positioned across (DLH group) and in the other six along (DLV group) the midline. At 6 months after implantation, mesh deformation, structural rearrangement, and repaired abdominal wall biomechanics were evaluated. Histological sections were stained with van Giesen and Mallory's trichrome. The anisotropic mechanical properties of the mesh and fascial layers coincided in the DLH group, but did not correspond to each other in the DLV group. In the DLV group, meshes were stretched in width by 11.4% and reduced in length by 12.7%. In all animals, the lower edge of the mesh was shifted to a defect area with margin hernia formation in two rats. Constant shear stress caused disproportional connective tissue formation. Repaired abdominal wall lost its natural elasticity. In the DLH group, the mesh deformation was minimal. Formed connective tissue was tightly associated with the anterior layer and did not differ from it in composition. The mechanical properties of repaired abdominal wall were close to those of the anterior layer. In prosthetic hernia repair, the mechanical properties of surgical mesh should correspond with those of the fascia being repaired. A mismatch of mechanical properties may result in implant deformation, abdominal wall biomechanics impairment, and recurrent herniation at the edges of the meshes.

  10. Characterization of the structure and properties of authentic and counterfeit polypropylene surgical meshes.

    Science.gov (United States)

    McDermott, M K; Isayeva, I S; Thomas, T M; Lee, A S; Lucas, A D; Witkowski, C N; Hutter, J C

    2006-04-01

    A counterfeit version of the Ethicon Prolene polypropylene mesh was distributed to hospitals and clinics and unintentionally implanted into patients undergoing tension-free hernia repair. On December 19, 2003, the Food and Drug Administration (FDA) issued a public health web notification indicating that the counterfeit mesh was not sterile or safe to use. To develop safety recommendations for patients with the counterfeit mesh implant, we compared the counterfeit's structural, physical, chemical and mechanical properties with polypropylene meshes previously cleared by FDA. The mesh fibers for all the products tested were found to have similar chemical and physical properties. The mechanical properties were directly related to the knitted structure (loop size, repeat distance, fabric tightness) and the porosity. Extracts from the counterfeit mesh passed cytotoxicity screening tests. The FDA further recommended that if the mesh had been inadvertently implanted, then those patients should be monitored as would be the practice for any patient with an implanted surgical mesh.

  11. Laparoscopic intraperitoneal mesh fixation with fibrin sealant (Tisseel®) vs. titanium tacks: a randomised controlled experimental study in pigs

    DEFF Research Database (Denmark)

    Eriksen, J.R.; Bech, Jakob Ilsted; Linnemann, D.

    2008-01-01

    chronic) pain after LVHR. Therefore, non-invasive and patient-friendly mesh fixation methods must be considered. The present study was designed to investigate the technical applicability, safety and effect of Tisseel (R) for intraperitoneal mesh fixation. Methods Nine 40-kg Danish Landrace female pigs had...... two pieces of MotifMESH (R) and two pieces of Proceed (R) mesh fixed in the intraperitoneal position by a laparoscopic technique. The two pieces of the same mesh were fixed with fibrin glue (Tisseel) and titanium tacks, respectively. All pigs were euthanised on the 30th postoperative day and the mesh...... feasible in a pig model. There is still no evidence that fibrin-sealing alone is appropriate for intraperitoneal mesh fixation in hernia repair, but the technique might become an alternative or supplement to mechanical mesh fixation. Until then, further experimental research in animal hernia models...

  12. In Vivo Evaluation of Bacterial Infection Involving Morphologically Different Surgical Meshes

    NARCIS (Netherlands)

    Engelsman, Anton F.; van Dam, Gooitzen M.; van der Mei, Henny C.; Busscher, Henk J.; Ploeg, Rutger J.

    2010-01-01

    Objective: To study the influence of morphology of surgical meshes on the course of bacterial infection under the influence of the host immune system in an in vivo chronic bacterial infection model. Background: The use of prosthetic meshes has increased dramatically the last decades in abdominal wal

  13. Laparoscopic intraperitoneal mesh fixation with fibrin sealant (Tisseel((R))) vs. titanium tacks: a randomised controlled experimental study in pigs

    DEFF Research Database (Denmark)

    Eriksen, J.R.; Bech, J.I.; Linnemann, D.

    2008-01-01

    chronic) pain after LVHR. Therefore, non-invasive and patient-friendly mesh fixation methods must be considered. The present study was designed to investigate the technical applicability, safety and effect of Tisseel((R)) for intraperitoneal mesh fixation. METHODS: Nine 40-kg Danish Landrace female pigs...... had two pieces of MotifMESH((R)) and two pieces of Proceed((R)) mesh fixed in the intraperitoneal position by a laparoscopic technique. The two pieces of the same mesh were fixed with fibrin glue (Tisseel) and titanium tacks, respectively. All pigs were euthanised on the 30th postoperative day...... with Tisseel is safe and technically feasible in a pig model. There is still no evidence that fibrin-sealing alone is appropriate for intraperitoneal mesh fixation in hernia repair, but the technique might become an alternative or supplement to mechanical mesh fixation. Until then, further experimental...

  14. Orbital Wall Reconstruction with Titanium Mesh: Retrospective Study of 24 Patients

    OpenAIRE

    Gabrielli, Mario Francisco; Monnazzi, Marcelo Silva; Passeri, Luis Augusto; Carvalho, Waldner Ricardo; Gabrielli, Marisa; Hochuli-vieira, Eduardo [UNESP

    2011-01-01

    The aim of this study was to evaluate the efficacy and safety of traumatic orbital defect reconstruction with titanium mesh. A retrospective study was made. Evaluations were made after a minimum postoperative follow-up of 12 months, looking for the main complications. Twenty-four patients were included in this evaluation; 19 were male (79.1%) and 5 (20.8%) were female. The main injury etiology was vehicle accidents (50%) followed by other causes. Fourteen patients (58.3%) presented orbital fl...

  15. Trends in use of surgical mesh for pelvic organ prolapse.

    Science.gov (United States)

    Jonsson Funk, Michele; Edenfield, Autumn L; Pate, Virginia; Visco, Anthony G; Weidner, Alison C; Wu, Jennifer M

    2013-01-01

    Limited data exist on the rates of pelvic organ prolapse procedures utilizing mesh. The objective of this study was to examine trends in vaginal mesh prolapse procedures (VMs), abdominal sacrocolpopexy (ASC), and minimally invasive sacrocolpopexy (MISC) from 2005 to 2010. We utilized deidentified, adjudicated health care claims data from across the United States from 2005 to 2010. Among women 18 years old or older, we identified all mesh prolapse procedures based on current procedural terminology codes (57267 for VM, 57280 for ASC, and 57425 for MISC). VM procedures included all vaginal prolapse surgeries in which mesh was placed, whether in the anterior, apical, or posterior compartment. We estimated rates per 100,000 person-years (100,000 py) and 95% confidence intervals (CIs). During 78.5 million person-years of observation, we identified 60,152 mesh prolapse procedures, for a rate of 76.0 per 100,000 py (95% CI, 73.6-78.5). Overall, VMs comprised 74.9% of these surgeries for an overall rate of 56.9 per 100,000 py (95% CI, 55.0-58.9). Rates of ASC and MISC were considerably lower at 12.0 per 100,000 py (95% CI, 11.6-12.5) and 9.5 per 100,000 py (95% CI, 9.2-9.9), respectively. Among sacrocolpopexies, ASC was more common than MISC in 2005-2007; however, since 2007, the rate of MISC has increased, whereas the rate of ASC has decreased. Regarding trends by age, VM was considerably more common than sacrocolpopexies at all ages, and ASC was more common than MISC in women older than 50 years. From 2005 to 2010, the rate of mesh prolapse procedures has increased, with vaginal mesh surgeries constituting the vast majority. Copyright © 2013 Mosby, Inc. All rights reserved.

  16. Porous Structure Characterization in Titanium Coating for Surgical Implants

    Directory of Open Access Journals (Sweden)

    M.V. Oliveira

    2002-09-01

    Full Text Available Powder metallurgy techniques have been used to produce controlled porous structures, such as the porous coatings applied for dental and orthopedic surgical implants, which allow bony tissue ingrowth within the implant surface improving fixation. This work presents the processing and characterization of titanium porous coatings of different porosity levels, processed through powder metallurgy techniques. Pure titanium sponge powders were used for coating and Ti-6Al7Nb powder metallurgy rods were used as substrates. Characterization was made through quantitative metallographic image analysis using optical light microscope for coating porosity data and SEM analysis for evaluation of the coating/substrate interface integrity. The results allowed optimization of the processing parameters in order to obtain porous coatings that meet the requirements for use as implants.

  17. Synthetic surgical meshes used in abdominal wall surgery: Part I-materials and structural conformation.

    Science.gov (United States)

    Todros, S; Pavan, P G; Natali, A N

    2017-04-01

    Surgical implants are commonly used in abdominal wall surgery for hernia repair. Many different prostheses are currently offered to surgeons, comprising permanent synthetic polymer meshes and biologic scaffolds. There is a wide range of synthetic meshes currently available on the market with differing chemical compositions, fiber conformations, and mesh textures. These chemical and structural characteristics determine a specific biochemical and mechanical behavior and play a crucial role in guaranteeing a successful post-operative outcome. Although an increasing number of studies report on the structural and mechanical properties of synthetic surgical meshes, nowadays there are no consistent guidelines for the evaluation of mechanical biocompatibility or common criteria for the selection of prostheses. The aim of this work is to review synthetic meshes by considering the extensive bibliography documentation of their use in abdominal wall surgery, taking into account their material and structural properties, in Part I, and their mechanical behavior, in Part II. The main materials available for the manufacture of polymeric meshes are described, including references to their chemical composition, fiber conformation, and textile structural properties. These characteristics are decisive for the evaluation of mesh-tissue interaction process, including foreign body response, mesh encapsulation, infection, and adhesion formation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 689-699, 2017. © 2015 Wiley Periodicals, Inc.

  18. Characterizing the ex vivo mechanical properties of synthetic polypropylene surgical mesh.

    Science.gov (United States)

    Li, Xinxin; Kruger, Jennifer A; Jor, Jessica W Y; Wong, Vivien; Dietz, Hans P; Nash, Martyn P; Nielsen, Poul M F

    2014-09-01

    The use of synthetic polypropylene mesh for hernia surgical repair and the correction of female pelvic organ prolapse have been controversial due to increasing post-operative complications, including mesh erosion, chronic pain, infection and support failure. These morbidities may be related to a mismatch of mechanical properties between soft tissues and the mesh. The aim of this study was to gain a better understanding of the biomechanical behavior of Prolene polypropylene mesh (Ethicon, Sommerville, NJ, USA), which is widely used for a variety of surgical repair procedures. The stiffness and permanent deformation of Prolene mesh were compared in different directions by performing uniaxial tensile failure tests, cyclic and creep tests at simulated physiological loads in the coursewise (0°), walewise (90°) and the diagonal (45°) directions. Failure tests suggest that the mechanical properties of the mesh is anisotropic; with response at 0° being the most compliant while 90° was the stiffest. Irreversible deformation and viscoelastic behavior were observed in both cyclic and creep tests. The anisotropic property may be relevant to the placement of mesh in surgery to maximize long term mesh performance. The considerable permanent deformation may be associated with an increased risk of post-operative support failure.

  19. Direct metal laser sintering (DMLS) of a customized titanium mesh for prosthetically guided bone regeneration of atrophic maxillary arches.

    Science.gov (United States)

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

    2011-11-01

    This study describes a protocol for the direct manufacturing of a customized titanium mesh using CAD-CAM procedures and rapid prototyping to augment maxillary bone and minimize surgery when severe atrophy or post-oncological deformities are present. Titanium mesh and particulate autogenous plus bovine demineralised bone were planned for patient rehabilitation. Bone augmentation planning was performed using the pre-op CT data set in relation to the prosthetic demands, minimizing the bone volume to augment at the minimum necessary for implants. The containment mesh design was used to prototype the 0.6 mm thickness customized titanium mesh, by direct metal laser sintering. The levels of regenerated bone were calculated using the post-op CT data set, through comparison with the pre-op CT data set. The mean vertical height difference of the crestal bone was 2.57 mm, while the mean buccal-palatal dimension of thickness difference was 3.41 mm. All planned implants were positioned after an 8 month healing period using two-step implant surgery, and finally restored with a partial fixed prosthesis. We present a viable and reproducible method to determine the correct bone augmentation prior to implant placement and CAD-CAM to produce a customized direct laser-sintered titanium mesh that can be used for bone regeneration.

  20. Comparison of titanium mesh implants with PLA-hydroxyapatite coatings for maxillofacial cancer reconstruction

    Science.gov (United States)

    Tverdokhlebov, S. I.; Choinzonov, E. L.; Kolokolova, O. V.; Cherdyntseva, N. V.

    2016-08-01

    Since 2013 physics of TPU and oncologists from the TCRI with participation of the "ConMet" company (Moscow) and the "Sintel" company (Tomsk Special Economic Zone resident) have been working on the theme entitled "Development of the composite implants for reconstructive surgery of a craniofacial areas of the traumatological and oncological patients" supported with the Federal Program "R&D, part 1.3". The goal was to develop the maxillo-facial implants on the basis of the transformable titanium mesh with PLA & hydroxyapatite coating. According to the Contract No. 14.578.21.0031, the team of developers had to start supplying these advanced implants to the industrial partners up to 2017. This research was supported with the preliminary market researches by the ISPMS SB RAS and the TP "MF". The stages of preliminary market researches were: 1) research of the Worldwide CMF market; 2) forecasting the BRIC CMF market up to 2020; 3) the total Russian market (epidemiology) estimation as a sum of official calculations and statistics; 4) looking for the best foreign analogue prices, comparing their and our implant properties; 5) search for the best Russian analogues; 6) the investigation of the world patent database Espacenet for the last years, and finding the owners and applicants of patents of CMF osteosynthesis plates on the basis of titanium coated with PLA & hydroxyapatite; 7) comparison of the domestic implants, and making conclusions. Several variants of the meshes have got the equal quality with the best foreign and Russian implants. The closest analogues were titanium, polyethylene, PEEK composite meshes suited to the patient shape by the Synthes company in 2014, and the only hybrid titanium "Grey" implant with layers of gelatin, dextran, collagen, HAP & BMP-2 was found. This implant was produced by Russian institution, and it was mentioned in the report on clinical trials by L.A. Pavlova et al., 2014 [1]. There are no manufacturers of the coated implants in Russia

  1. Influence of rhBMP-2 on rat bone marrow stromal cells cultured on titanium fiber mesh.

    NARCIS (Netherlands)

    Vehof, J.W.M.; Ruijter, J.E. de; Spauwen, P.H.M.; Jansen, J.A.

    2001-01-01

    Titanium (Ti) fiber mesh is a candidate scaffold material for the creation of bone graft substitutes (BGS). Two densities (3.54 x 10(4) cells/cm(2) [LD or low density] and 3.54 x 10(5) cells/cm(2) [HD or high density]) of rat bone marrow stromal cells were seeded on Ti-fiber mesh discs. Cells were c

  2. Integrating a novel shape memory polymer into surgical meshes to improve device performance during laparoscopic hernia surgery

    Science.gov (United States)

    Zimkowski, Michael M.

    About 600,000 hernia repair surgeries are performed each year. The use of laparoscopic minimally invasive techniques has become increasingly popular in these operations. Use of surgical mesh in hernia repair has shown lower recurrence rates compared to other repair methods. However in many procedures, placement of surgical mesh can be challenging and even complicate the procedure, potentially leading to lengthy operating times. Various techniques have been attempted to improve mesh placement, including use of specialized systems to orient the mesh into a specific shape, with limited success and acceptance. In this work, a programmed novel Shape Memory Polymer (SMP) was integrated into commercially available polyester surgical meshes to add automatic unrolling and tissue conforming functionalities, while preserving the intrinsic structural properties of the original surgical mesh. Tensile testing and Dynamic Mechanical Analysis was performed on four different SMP formulas to identify appropriate mechanical properties for surgical mesh integration. In vitro testing involved monitoring the time required for a modified surgical mesh to deploy in a 37°C water bath. An acute porcine model was used to test the in vivo unrolling of SMP integrated surgical meshes. The SMP-integrated surgical meshes produced an automated, temperature activated, controlled deployment of surgical mesh on the order of several seconds, via laparoscopy in the animal model. A 30 day chronic rat model was used to test initial in vivo subcutaneous biocompatibility. To produce large more clinical relevant sizes of mesh, a mold was developed to facilitate manufacturing of SMP-integrated surgical mesh. The mold is capable of manufacturing mesh up to 361 cm2, which is believed to accommodate the majority of clinical cases. Results indicate surgical mesh modified with SMP is capable of laparoscopic deployment in vivo, activated by body temperature, and possesses the necessary strength and

  3. Development and demonstration of a novel computer planning solution for predefined correction of enophthalmos in anophthalmic patients using prebended 3D titanium-meshes--a technical note.

    Science.gov (United States)

    Rana, Majeed; Essig, Harald; Rücker, Martin; Ruecker, Martin; Gellrich, Nils-Claudius

    2012-11-01

    Ablative surgery of the orbit is often associated with dramatic changes in facial geometry. Surgical intervention is often necessary to correct the functional and esthetic appearance in those patients who are anophthalmic, having an intact eyelid appearance and an orbital prosthesis. The outcome of the surgical correction depends on the shape of the orbital implants and their adequate placement. In the case of comparatively small rearrangements, the effect of implants on soft tissues can be estimated by surgeons on the basis of their experience. However, large deformities in complex cases (including large deformation of soft tissue or asymmetry) can be hardly predicted on the basis of simple empirical considerations. The purpose of the present technical note was to describe a new procedure of inverse design of customized orbital titanium meshes. To demonstrate this procedure, an anophthalmic patient with superior sulcus deformity and enophthalmos was enrolled. The volume and structure of the extraocular muscles, soft tissue, and bony structure of the orbital walls were examined using high-resolution multislice computed tomography. Next, a geometric model of the patient's anatomy was generated from the tomography data. Afterward, the orbital prosthesis was virtually relocated to a new position. Then, the desired correction of the particular soft tissue regions was performed using virtual sculpturing tools. Next, the deformation of the soft tissues and initial prosthesis boundaries were computed from the predefined displacements of the relocated tissue regions with the help of the Finite Element Method. The differential volume between the initial and designated position of the orbital prosthesis yielded the preferred implant shape required to effect the desired correction of soft tissue. During surgery, the preplanned position of the customized titanium meshes was guided using a navigation system. Although the inverse design of custom-tailored titanium meshes for

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

    Directory of Open Access Journals (Sweden)

    Ho Y.C.

    2010-06-01

    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.

  5. Ectopic bone formation in rat marrow stromal cell/titanium fiber mesh scaffold constructs: effect of initial cell phenotype.

    NARCIS (Netherlands)

    Holtorf, H.L.; Jansen, J.A.; Mikos, A.G.

    2005-01-01

    Titanium fiber mesh scaffolds have been shown to be a suitable material for culture of primary marrow stromal cells in an effort to create tissue engineered constructs for bone tissue replacement. In native bone tissue, these cells are known to attach to extracellular matrix molecules via integrin r

  6. Orthotopic bone formation in titanium fiber mesh loaded with platelet-rich plasma and placed in segmental defects.

    NARCIS (Netherlands)

    Kroese-Deutman, H.C.; Vehof, J.W.M.; Spauwen, P.H.M.; Stoelinga, P.J.W.; Jansen, Jarno

    2008-01-01

    The effect of platelet-rich plasma (PRP) on bone formation was investigated in a rabbit segmental radial defect model. The purpose of the study was to evaluate the bone inductive properties of PRP with titanium fiber mesh and autologous bone chips in a 15-mm rabbit radial defect model. Eighteen New

  7. Titanium mesh as a low-profile alternative for tension-band augmentation in patella fracture fixation: A biomechanical study.

    Science.gov (United States)

    Dickens, Aaron J; Salas, Christina; Rise, LeRoy; Murray-Krezan, Cristina; Taha, Mahmoud Reda; DeCoster, Thomas A; Gehlert, Rick J

    2015-01-01

    We performed a simple biomechanical study to compare the fixation strength of titanium mesh with traditional tension-band augmentation, which is a standard treatment for transverse patella fractures. We hypothesised that titanium mesh augmentation is not inferior in fixation strength to the standard treatment. Twenty-four synthetic patellae were tested. Twelve were fixed with stainless steel wire and parallel cannulated screws. Twelve were fixed with parallel cannulated screws, augmented with anterior titanium mesh and four screws. A custom test fixture was developed to simulate a knee flexed to 90°. A uniaxial force was applied to the simulated extensor mechanism at this angle. A non-inferiority study design was used to evaluate ultimate force required for failure of each construct as a measure of fixation strength. Stiffness of the bone/implant construct, fracture gap immediately prior to failure, and modes of failure are also reported. The mean difference in force at failure was -23.0 N (95% CI: -123.6 to 77.6N) between mesh and wire constructs, well within the pre-defined non-inferiority margin of -260 N. Mean stiffness of the mesh and wire constructs were 19.42 N/mm (95% CI: 18.57-20.27 N/mm) and 19.49 N/mm (95% CI: 18.64-20.35 N/mm), respectively. Mean gap distance for the mesh constructs immediately prior to failure was 2.11 mm (95% CI: 1.35-2.88 mm) and 3.87 mm (95% CI: 2.60-5.13 mm) for wire constructs. Titanium mesh augmentation is not inferior to tension-band wire augmentation when comparing ultimate force required for failure in this simplified biomechanical model. Results also indicate that stiffness of the two constructs is similar but that the mesh maintains a smaller fracture gap prior to failure. The results of this study indicate that the use of titanium mesh plating augmentation as a low-profile alternative to tension-band wiring for fixation of transverse patella fractures warrants further investigation. Copyright © 2015 Elsevier Ltd. All

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Low Profile Mesh Plating for Patella Fractures: Video of a Novel Surgical Technique.

    Science.gov (United States)

    Verbeek, Diederik O; Hickerson, Lindsay E; Warner, Stephen J; Helfet, David L; Lorich, Dean G

    2016-08-01

    Patella fractures can be challenging to treat particularly in the presence of inferior pole comminution. In this video we present a novel surgical technique for the treatment of patella fractures using a small fragment low profile mesh plate. Key points are the surgical exposure with direct visualization of the articular reduction, the preparation of the mesh plate to accommodate patellar anatomy and the augmentation of the construct using Krackow sutures to address inferior pole comminution. Low profile mesh plating allows for multiplanar fixation of patella fractures while avoiding implant and fixation problems related to tension band fixation. Our early experience with this technique is encouraging and it appears that this technique is useful for the treatment of the majority of patella fractures.

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

    Directory of Open Access Journals (Sweden)

    Jacek Białecki

    2014-01-01

    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.

  11. Hip joint replacement using monofilament polypropylene surgical mesh: an animal model.

    Science.gov (United States)

    Białecki, Jacek; Majchrzycki, Marian; Szymczak, Antoni; Klimowicz-Bodys, Małgorzata Dorota; Wierzchoś, Edward; Kołomecki, Krzysztof

    2014-01-01

    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.

  12. Patient recall 6 weeks after surgical consent for midurethral sling using mesh

    Science.gov (United States)

    McFadden, Brook L.; Hammil, Sarah L.; Constantine, Melissa L.; Tarr, Megan E.; Kenton, Kimberly S.; Abed, Husam T.; Sung, Vivian W.; Rogers, Rebecca G.

    2017-01-01

    Introduction and hypothesis We aimed to determine patient recall of specific surgical risks and benefits discussed during consent for midurethral sling (MUS) surgery immediately after consent and at 6 weeks follow-up. Specifically we sought to determine whether or not women recalled specific risks related to the placement of mesh. Methods Surgeons consented patients for MUS in their usual fashion during audio recorded consent sessions. After consent and again at 6 weeks postoperatively, women completed a checklist of risks, benefits, alternatives, and general procedural items covered during consent. In addition, women completed the Decision Regret Scale for Pelvic Floor Disorders (DRS-PFD). Audio files were used to verify specific risks, benefits, alternatives, and procedural items discussed at consent. Recall of specific risks, benefits, and alternatives were correlated with DRS-PFD scores. Results Sixty-three women completed checklists immediately post consent and at 6 weeks postoperatively. Six-week recall of benefits, alternatives, and description of the operation did not change. Surgical risk recall as measured by the patient checklist deteriorated from 92 % immediately post consent to 72 % at 6 weeks postoperatively (p surgical risk recall and surgical complications (r =.31, p = .02). Conclusions Recall of MUS surgery risks deteriorated overtime. Specifically, women forgot that mesh was placed or might erode. Further investigations into methods and measures of adequate consent that promote recall of long-term surgical risks are needed. PMID:23818127

  13. Controllable preparation of TiO{sub 2} nanowire arrays on titanium mesh for flexible dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenwu; Lu, Hui; Zhang, Mei; Guo, Min, E-mail: guomin@ustb.edu.cn

    2015-08-30

    Graphical abstract: TiO{sub 2} nanowire arrays with controlled morphology and density have been synthesized on Ti mesh substrates by hydrothermal approach for flexible dye-sensitized solar cells which showed well photovoltaic efficiency of 3.42%. - Highlights: • Flexible titanium mesh was first used for hydrothermal preparation of TiO{sub 2} NWAs. • The formation mechanism of the TiO{sub 2} nanostructures was discussed. • The density, average diameter, and morphology of TiO{sub 2} NWAs can be controlled. • The effects of the sensitization temperature and time on the properties were studied. - Abstract: TiO{sub 2} nanowire arrays (NWAs) with an average diameter of 80 nm have been successfully synthesized on titanium (Ti) mesh substrates via hydrothermal method. The effects of preparing conditions such as concentration of NaOH solution, reaction time, and hydrothermal temperature on the growth of TiO{sub 2} nanoarrays and its related photovoltaic properties were systematically investigated by scanning electron microscopy, X-ray diffraction, and photovoltaic properties test. The growth mechanism of the Ti mesh-supported TiO{sub 2} nanostructures was discussed in detail. Moreover, a parametric study was performed to determine the optimized temperature and time of the dye sensitized process for the flexible dye-sensitized solar cell (DSSC). It is demonstrated that hydrothermal parameters had obvious influence on the morphology and growth density of the as-prepared TiO{sub 2} nanoarrays. In addition, the performance of the flexible DSSC depended strongly on the sensitization temperature and time. By utilizing Ti mesh-supported TiO{sub 2} NWAs (with a length of about 14 μm) as a photoanode, the flexible DSSC with a short circuit current density of 10.49 mA cm{sup −2}, an open-circuit voltage of 0.69 V, and an overall power conversion efficiency of 3.42% was achieved.

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

    Directory of Open Access Journals (Sweden)

    Reinbold J

    2017-09-01

    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

  15. Application of anterior decompression and reconstruction using titanium mesh with locking plates in the management of cervical spondylotic myelopathy

    Institute of Scientific and Technical Information of China (English)

    Maolin He; Zengming Xiao; Shide Li; Qianfen Chen

    2008-01-01

    Objective:To observe the clinical effect of anterior decompression and reconstruction using titanium mesh with locking plates in the treatment of cervical spondylotic myelopathy.Methods:One hundred and twenty patients with cervical spondylotic myelopathy were treated by anterior decompression and reconstruction using titanium mesh with locking plates.There were 66 men and 54 women ranges in age from 37 to 72 Years(mean age, 58.3 years).The mean Japanese orthopedic surgery association(JOA) scale was 9.6 points before operation.Patients were followed up clinically and radiographically.Results:Having stood surgery well, the operation time ranged between 60-100 min and bleeding during operation ranged between 20-200 ml.There were no case of postoperative infection, recurrent laryngeal nerve palsy, or esophageal or tracheal laceration or rupture.The average follow-up period was 14.3 months(range, 12 to 24 months) in 96 who were followed up.At the last follow-up visit the mean JOA scale had improved to 14.4 points, reflecting an improve ment of 4.8 points.The results were considered to be excellent in 87 patients, good in 25, fair in 6, and poor in 2.No hardware-related complications or adjacent segment degenerative changes were encountered during the follow-up periods.Stable bone union was observed in all cases and the average time required for fusion was 5.7 months.Conclusion:Titanium mesh filled with autologous bone graft can avoid the complications associated with harvesting bone from the iliac crest donor site.When combined with cervical anterior locking plate, it can obtain satisfatory clinical results for the treatment of cervical spondylotic myelopathy.

  16. Use of a titanium mesh "shelter" combined with the soft tissue matrix expansion (tent pole) grafting in the reconstruction of a severely resorbed edentulous mandible. Technical note.

    Science.gov (United States)

    Sverzut, Cássio Edvard; Trivellato, Alexandre Elias; Sverzut, Alexander Tadeu

    2015-01-01

    Patients wearing complete dentures for a long time usually exhibit lack of bone and keratinized mucosa in the bearing area due to bone resorption. The patients suffering from this phenomenon usually have unstable and non-retentive complete denture, which result in constant trauma to the mucosa, pain, functional limitations and worsening of facial esthetics. An innovative technique has been described in which a novel surgical approach using osseointegrated dental implants as "tent poles" was applied concomitant with particulate autogenous bone graft. The authors claim that the control and maintenance of the surgically expanded soft tissue volume should prevent graft resorption in the long term. Nevertheless, resorption of the bone graft is usually more significant where the bone mass is poorer, in the mandibular body. This paper describes a case of severely resorbed edentulous mandible in which the "tent pole" technique was applied with some modifications. Use of the titanium mesh "shelters" and two additional implants was effective in "protecting" the bone graft in the posterior portion of the mandibular body increasing bone mass volume in this area. Furthermore, we believe that this kind of graft "protection" on the whole residual alveolar ridge can increase the width of bone mass gain optimizing the "tent pole" technique.

  17. Characteristics and Efficacy of a New 3-Dimensional Printed Mesh Structure Titanium Alloy Spacer for Posterior Lumbar Interbody Fusion.

    Science.gov (United States)

    Chung, Sung-Soo; Lee, Kyung-Joon; Kwon, Yoo-Beom; Kang, Kyung-Chung

    2017-08-17

    This study evaluated the characteristics of a newly developed 3-dimensional printed mesh structure titanium spacer and its efficacy for posterior lumbar interbody fusion. Posterior lumbar interbody fusion with this spacer was performed at 53 segments (40 patients; mean age, 64 years; range, 51-73 years). Data were collected prospectively. Radiographic characteristics were analyzed with changes in interbody height, instability of the segments, formation of bone bridges around the implants, and pseudarthrosis, as determined by dynamic radiographs and postoperative computed tomography scans. Clinical outcomes were evaluated with the visual analog scale for the low back and extremities, the Oswestry Disability Index, and the 36-Item Short Form Survey. Radiographically, preoperative anterior and posterior interbody height was significantly increased immediately postoperatively (P3-dimensional printed mesh structure titanium spacer showed satisfactory radiographic and clinical results, with no cases of pseudarthrosis or revision, including posterior lumbar interbody fusion at L5-S1. [Orthopedics. 201x; xx(x):xx-xx.]. Copyright 2017, SLACK Incorporated.

  18. Surgical repair of pectus excavatum in young adults using the DualMesh 2-mm Gore-Tex

    National Research Council Canada - National Science Library

    Kotoulas, Christophoros; Papoutsis, Dimitrios; Tsolakis, Konstantinos; Laoutidis, Georgios

    2003-01-01

    ... Robicsek technique, based on Ravitch's stages, with the use of DualMesh 2-mm Gore-Tex ® to support the sternum posteriorly. 2 Materials and methods 2.1 Patients Between March 2000 and March 2003, surgical repair of PE using the DualMesh 2-mm Gore-Tex ® was performed in 21 male patients, average age 21 years (range 19–27). Preoperative evaluation...

  19. Anterior D-rod and titanium mesh fixation for acute mid-lumbar burst fracture with incomplete neurologic deficits A prospective study of 56 consecutive patients

    Directory of Open Access Journals (Sweden)

    Zhe-yuan Huang

    2015-01-01

    Conclusion: Good mid term clinicoradiological results of anterior decompression with D-rod and titanium mesh fixation for suitable patients with mid-lumbar burst fractures with incomplete neurologic deficits can be achieved. The incident rate of complications was low. D-rod is a reliable implant and has some potential advantages in L4 vertebral fractures.

  20. Surgical treatment of iliotibial band friction syndrome with the mesh technique.

    Science.gov (United States)

    Sangkaew, Chanchit

    2007-05-01

    Iliotibial band friction syndrome is an overuse injury caused by repetitive friction of the iliotibial band across the lateral femoral epicondyle. It has been reported to afflict long-distance runners, cyclists and military personnel. Initial treatments include rest, anti-inflammatory medication, modalities (ice or heat), stretching, physical therapy, and possibly a corticosteroid injection. If the conservative treatment is unsuccessful, surgery has been advocated. This report describes a new surgical technique to release the pressure on the lateral femoral epicondyle in a patient who failed the nonoperative efforts. The surgery was performed with the knee held in 30 degrees of flexion and consisted of multiple 2 mm long incisions across the fiber of the iliotibial band covering the lateral femoral epicondyle. There were six incisions, each of which was 4 mm apart. The incisions were spontaneously enlarged and changed to several punctured wounds (mesh appearance) by the tension of iliotibial band, resulted in relaxing the tight iliotibial band over the lateral femoral epicondyle. At the final follow-up 2 years after surgery the patient was pain free and could resume his previous occupational activities. The surgical result of the present technique is encouraging.

  1. Bony healing of unstable thoracolumbar burst fractures in the elderly using percutaneously applied titanium mesh cages and a transpedicular fixation system with expandable screws.

    Directory of Open Access Journals (Sweden)

    Anica Eschler

    Full Text Available There is a high incidence of vertebral burst fractures following low velocity trauma in the elderly. Treatment of unstable vertebral burst fractures using the same principles like in stable vertebral burst fractures may show less favourable results in terms of fracture reduction, maintenance of reduction and cement leakage. In order to address these shortcomings this study introduces cementless fixation of unstable vertebral burst fractures using internal fixators and expandable intravertebral titanium mesh cages in a one-stage procedure via minimum-invasive techniques.A total of 16 consecutive patients (median age 76 years, range 58-94 with unstable thoracolumbar burst fractures and concomitant osteoporosis were treated by an internal fixator inserted via minimum invasive technique one level above and below the fractured vertebra. Fracture reduction was achieved and maintained by transpedicular placement of two titanium mesh cages into the fractured vertebral body during the same procedure. Intra- and postoperative safety of the procedure as well as analysis of reduction quality was analysed by 3D C-arm imaging or CT, respectively. Clinical and radiographic follow-up averaged 10.4 months (range 4.5-24.5.Stabilization of the collapsed vertebral body was achieved in all 16 cases without any intraoperative complication. Surgical time averaged 102 ± 6.6 minutes (71-194. The postoperative kyphotic angle (KA and Cobb angle revealed significant improvements (KA 13.7° to 7.4°, p < 0.001; Cobb 9.6° to 6.0°, p < 0.002 with partial loss of reduction at final follow-up (KA 8.3°, Cobb 8.7°. VAS (Visual Analogue Scale improved from 7.6 to 2.6 (p < 0.001. Adjacent fractures were not observed. One minor (malposition of pedicle screw complication was encountered.Cementless fixation of osteoporotic burst fractures revealed substantial pain relief, adequate maintenance of reduction and a low complication rate. Bony healing after unstable osteoporotic burst

  2. Cost analysis of surgical treatment for pelvic organ prolapse by laparoscopic sacrocolpopexy or transvaginal mesh.

    Science.gov (United States)

    Carracedo, D; López-Fando, L; Sánchez, M D; Jiménez, M Á; Gómez, J M; Laso, I; Rodríguez, M Á; Burgos, F J

    2017-03-01

    The objective of this study is to compare direct costs of repairing pelvic organ prolapse by laparoscopic sacrocolpopexy (LS) against vaginal mesh (VM). Our hypothesis is the correction of pelvic organ prolapse by LS has a similar cost per procedure compared to VM. We made a retrospective comparative analysis of medium cost per procedure of first 69 consecutive LS versus first 69 consecutive VM surgeries. We calculate direct cost for each procedure: structural outlays, personal, operating room occupation, hospital stay, perishable or inventory material and prosthetic material. Medium cost per procedure were calculated for each group, with a 95% confidence interval. LS group has a higher cost related to a longer length of surgery, higher operating room occupation and anesthesia; VM group has a higher cost due to longer hospital stay and more expensive prosthetic material. Globally, LS has a lower medium cost per procedure in comparison to VM (5,985.7 €±1,550.8 € vs. 6,534.3 €±1,015.5 €), although it did not achieve statistical signification. In our midst, pelvic organ prolapse surgical correction by LS has at least similar cost per procedure compared to VM. Copyright © 2016 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Surgical repair of pectus excavatum in young adults using the DualMesh 2-mm Gore-Tex.

    Science.gov (United States)

    Kotoulas, Christophoros; Papoutsis, Dimitrios; Tsolakis, Konstantinos; Laoutidis, Georgios

    2003-12-01

    We present our surgical technique and clinical outcome of the surgical repair of pectus excavatum using the DualMesh 2-mm Gore-Tex, in 21 young adults. The main symptom was the exercise limitation in 15 patients. There were no postoperative complications and excellent cosmetic results were achieved. We can confirm that DualMesh seems to be the ideal material to support the sternum in its corrected position. Its advantages are the strength to stabilize well the chest wall, the quality to be detached easily from the pericardial surface even in the case of urgent median sternotomy due to its particular surfaces, the resistance to infection and the ability to be left in place permanently.

  4. Long-term anisotropic mechanical response of surgical meshes used to repair abdominal wall defects.

    Science.gov (United States)

    Hernández-Gascón, B; Peña, E; Pascual, G; Rodríguez, M; Bellón, J M; Calvo, B

    2012-01-01

    Routine hernia repair surgery involves the implant of synthetic mesh. However, this type of procedure may give rise to pain and bowel incarceration and strangulation, causing considerable patient disability. The purpose of this study was to compare the long-term behaviour of three commercial meshes used to repair the partially herniated abdomen in New Zealand White rabbits: the heavyweight (HW) mesh, Surgipro(®) and lightweight (LW) mesh, Optilene(®), both made of polypropylene (PP), and a mediumweight (MW) mesh, Infinit(®), made of polytetrafluoroethylene (PTFE). The implanted meshes were mechanical and histological assessed at 14, 90 and 180 days post-implant. This behaviour was compared to the anisotropic mechanical behaviour of the unrepaired abdominal wall in control non-operated rabbits. Both uniaxial mechanical tests conducted in craneo-caudal and perpendicular directions and histological findings revealed substantial collagen growth over the repaired hernial defects causing stiffness in the repair zone, and thus a change in the original properties of the meshes. The mechanical behaviour of the healthy tissue in the craneo-caudal direction was not reproduced by any of the implanted meshes after 14 days or 90 days of implant, whereas in the perpendicular direction, SUR and OPT achieved similar behaviour. From a mechanical standpoint, the anisotropic PP-lightweight meshes may be considered a good choice in the long run, which correlates with the structure of the regenerated tissue. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Electrocatalytic dechlorination of 2,3,5-trichlorophenol on palladium/carbon nanotubes-nafion film/titanium mesh electrode.

    Science.gov (United States)

    Sun, Zhirong; Ma, Xiaoyue; Hu, Xiang

    2017-06-01

    Palladium/carbon nanotubes-nafion film-modified titanium mesh electrode (Pd/CNTs-nafion film/Ti electrode) was prepared and used for catalytic dechlorination of 2,3,5-trichlorophenol (2,3,5-TCP). The influences of factors, such as Pd(2+) concentration, plating solution pH, and electrodeposition time and current, on the preparation of the electrode were studied by cyclic voltammetry (CV) to establish the optimal electrode preparation conditions. Additionally, the CV results highlighted that the addition of the CNTs-nafion film could enhance the electrochemical performance of the electrode. The Pd/CNTs-nafion film/Ti electrode was characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and inductively coupled plasma-atomic emission spectrometry (ICP-AES). The electrode exhibited good stability and high catalytic dechlorination capacity on 2,3,5-TCP-100 mg L(-1) 2,3,5-TCP was completely dechlorinated within 100 min at a dechlorination current of 5 mA and an initial solution pH of 2.3. High-performance liquid chromatography (HPLC) was used to detect the chlorinated phenolic intermediates, and the results revealed that the final products were mainly phenol. The kinetics studies revealed that the dechlorination of 2,3,5-TCP followed two-stage mixed order kinetics, and a possible degradation pathway for 2,3,5-TCP was proposed.

  6. Transvaginal mesh in repair of pelvic organs prolapse as a minimally invasive surgical procedure

    Directory of Open Access Journals (Sweden)

    Argirović Rajka

    2011-01-01

    Full Text Available Background/Aim. Prolapse of genital organs with or without urinary stress incontinention is the most often health problem in the elderly female population tending to increase with ageing. The aim of this study was to assess the perioperative complications and short-term outcomes of prolaps repair using transvaginal polypropylene mesh (Prolift system, Gynecare, Ethicon, USA. Methods. A retrospective study was conducted evaluating 96 women from September 2006 to January 2010 who undewent vaginal repair with implatation of a soft mesh manufactured by Gynecare, Ethicon, USA. Results. All the patients had a stage 3 or stage 4 prolapse according to the POP-Q system of ICS. Total mesh was used in 12 (13% patients isolated anterior mesh in 52 (54% patients and isolated posterior mesh in 32 (33% patients. We reported one intra-operative bladder injury and no other serious complications. At 3 months, all 96 patients were available for follow-up. Vaginal erosion occured in 9 (9.3% patients, shrinkage of mesh in 6 (6.2% patients and de novo urinary incontinence in 5 (5.2% patients. Failure rate was 6.25% (recurrent prolapse stage 3 or 4 even asymptomatic. Conclusion. Our study suggests that transvaginal polypropylene mesh applied with a tensionfree technique is a safe and effective method with low intraoperative complications and low morbidity rates. However, some complications are serious and require highly specialised management.

  7. Evaluation of dynamic creep properties of surgical mesh prostheses--uniaxial fatigue.

    Science.gov (United States)

    Velayudhan, Shiny; Martin, Darren; Cooper-White, Justin

    2009-10-01

    In this study, we examine the dynamic creep behavior of four commonly used commercial hernia meshes (Prolene, Ultrapro, Vypro, and Vypro II). The meshes, differing from each other with respect to composition and architecture, were tested under uniaxial tension at simulated physiological loads and environmental conditions. The changes in percentage strain elongation, secant modulus, and cyclic energy dissipation over 100,000 cycles were compared. All of the meshes evaluated were found to be overengineered compared to physiological-loading criteria and displayed good load-carrying performance. When all meshes were tested at 37 degrees C in physiological saline, they survived 100,000 cycles of sinusoidal loading without fracture, except Ultrapro. Interestingly, irrespective of the differences in structure and composition, all meshes underwent strain-hardening and permanent plastic deformation. Scanning electron micrographs of the meshes showed evidence of yarn thinning, decrimping, and fracture. The results of this study suggest that strain-hardening of the meshes under dynamic loading could be a possible cause for complications related to abdominal mobility during long-term implantations.

  8. Electrolytic trichloroethene degradation using mixed metal oxide coated titanium mesh electrodes.

    Science.gov (United States)

    Petersen, Matthew A; Sale, Thomas C; Reardon, Kenneth F

    2007-04-01

    Electrochemical systems provide a low cost, versatile, and controllable platform to potentially treat contaminants in water, including chlorinated solvents. Relative to bare metal or noble metal amended materials, dimensionally stable electrode materials such as mixed metal oxide coated titanium (Ti/MMO) have advantages in terms of stability and cost, important factors for sustainable remediation solutions. Here, we report the use of Ti/MMO as an effective cathode substrate for treatment of trichloroethene (TCE). TCE degradation in a batch reactor was measured as the decrease of TCE concentration over time and the corresponding evolution of chloride; notably, this occurred without the formation of commonly encountered chlorinated intermediates. The reaction was initiated when Ti/MMO cathode potentials were less than -0.8 V vs. the standard hydrogen electrode, and the rate of TCE degradation increased linearly with progressively more negative potentials. The maximum pseudo-first-order heterogeneous rate constant was approximately 0.05 cm min(-1), which is comparable to more commonly used cathode materials such as nickel. In laboratory-scale flow-though column reactors designed to simulate permeable reactive barriers (PRBs), TCE concentrations were reduced by 80-90%. The extent of TCE flux reduction increased with the applied potential difference across the electrodes and was largely insensitive to the spacing distance between the electrodes. This is the first report of the electrochemical reduction of a chlorinated organic contaminant at a Ti/MMO cathode, and these results support the use of this material in PRBs as a possible approach to manage TCE plume migration.

  9. Medicolegal issues surrounding devices and mesh for surgical treatment of prolapse and incontinence.

    Science.gov (United States)

    Nosti, Patrick A; Iglesia, Cheryl B

    2013-06-01

    Legal issues related to vaginal mesh devices for prolapse and incontinence include abnormal injury and inadequate informed consent. Although vaginal mesh devices are currently cleared through the 510(k) process, new developments at the US Food and Drug Administration requiring additional postmarket studies (522 studies) for transvaginal mesh for prolapse and mini-suburethral synthetic slings have been issued to ensure product safety and effectiveness. New initiatives including unique device identification numbers and the Pelvic Floor Disorders Registry have been developed to improve surveillance throughout the total product/device life cycle.

  10. Management of Implant Exposure in One-Stage Breast Reconstruction Using Titanium-Coated Polypropylene Mesh: Sub-Mammary Intercostal Perforator Flap.

    Science.gov (United States)

    De Riggi, Michele Antonio; Rocco, Nicola; Gherardini, Giulio; Esposito, Emanuela; D'Aiuto, Massimiliano

    2016-12-01

    One-stage implant-based breast reconstruction using titanium-coated polypropylene mesh is a novel approach widely used in Europe. Complication rates in breast reconstruction with the use of titanium-coated meshes seem to be comparable to those in patients with implant-based breast reconstruction alone. However, the use of synthetic meshes in implant-based breast reconstructive surgery leads to new clinical scenarios with the need for the breast surgeon to face new complications. We present an innovative treatment of implant exposure in the absence of infection in patients who underwent nipple-sparing mastectomy and immediate breast reconstruction with silicone implants and titanium-coated polypropylene mesh by using a pedicled sub-mammary intercostal perforator flap. Four patients who experienced implant exposure without infection have been treated with the use of a sub-mammary intercostal perforator flap. Whole coverage of the exposed implant/mesh with a sub-mammary intercostal perforator flap was obtained in all cases. No post-operative complications have been observed, whereas a pleasant aesthetic result has been achieved. Patients' post-operative quality of life and satisfaction levels were measured by the European Organisation for Research and Treatment of Cancer breast cancer-specific quality of life QLQ-BR23 questionnaire and showed an average good satisfaction with the post-operative outcomes (mean QLQ-BR23 score 1.9). For the first time, a sub-mammary intercostal perforator flap has been used with the aim of treating implant exposures without removing the prosthesis even in the presence of synthetic meshes, when wound infection was excluded. Although tested on a small series, the sub-mammary intercostal perforator flap might represent a simple, versatile and cost-effective procedure for the management of implant exposure following nipple-sparing mastectomy and immediate reconstruction with silicone implants and synthetic meshes. It should be considered to

  11. Bimaxillary protrusion with masseter muscle hypertrophy treated with titanium screw anchorage and masseter surgical reduction.

    Science.gov (United States)

    Hashimoto, Takashi; Kuroda, Shingo; Kamioka, Hiroshi; Mishima, Katsuaki; Sugahara, Toshio; Takano-Yamamoto, Teruko

    2009-04-01

    This case report describes the treatment of a patient with bimaxillary protrusion and masseter muscle hypertrophy. At age 21 years 7 months, this woman had temporomandibular disorder (TMD) symptoms, severe bimaxillary protrusion, and a prominent mandibular angle with facial asymmetry. After an attempt to alleviate the TMD symptoms with occlusal splint stabilization, portions of the masseter muscle and the mandible were surgically removed. Titanium screws were placed bilaterally in both arches, and a retraction force was applied. After active treatment for 38 months, the convexity of the facial profile with lip protrusion was improved remarkably, and good occlusion was achieved. The prominent mandibular angle with facial asymmetry was improved as a result of the surgical reduction of the masseter muscle and the modeling ostectomy near the masseteric tuberosity. The TMD symptoms disappeared, and the jaw movement pattern became normal. Therefore, our results suggest that this combination treatment would be useful for masseter muscle hypertrophy for morphologic and functional problems.

  12. The effect of titanium mesh implantation for the treatment of enophthalmos secondary to inferior orbital wall fracture%钛网眶底植入治疗眶下壁骨折眼球内陷的效果

    Institute of Scientific and Technical Information of China (English)

    于金国; 张静楷; 陈松; 韩琪; 颜华

    2015-01-01

    Objective To evaluate the effect of "S" shaped titanium mesh implantation on orbit floor for enophthalmos secondary to inferior orbital wall fracture.Methods The surgical effects of 17 eyes of 17 cases inferior orbital wall fracture who received "S" shaped titanium mesh implantation on orbit floor for orbital wall reconstruction were analyzed retrospectively.Preoperatively,there were 9 cases with enophthalmos between 2 to 3 mm,8 cases with enophthalmos between 3.5 to 4.5 mm,3 cases with diplopia,2 cases with apparent vertical globe dystopia.For all the cases,an inferior subciliary approach was performed,a "S" shaped titanium mesh plate was implanted under the periosteum to cover the area of the inferior orbital wall fracture for reconstruction of the orbital cavity.Results Postoperatively,on the follow-up period of 6-12 months,the enophthalmos of all cases was corrected to less than 2mm successfully,the preoperative diplopia disappeared in all the 3 cases,the vertical globe dystopia of 2 eases disappeared,and no visual complication was observed.No complication of infection,extrusion,rejection or migration of the implants occurred,however mild low eyelid retraction occurred in 1 case and disappeared at 8 month postoperatively.Conclusion "S" shaped titanium mesh plate implantation in orbital reconstruction for correcting enophthalmos secondary to inferior orbital wall fracture is safe and effective.%目的 评价S形钛网眶底植入治疗眶下壁骨折后眼球内陷的效果.方法 回顾性分析17例(17只眼)眶下壁骨折眼球内陷患者行S形钛网眶底植入手术的临床资料.术前眼球内陷2~3 mm者9例,眼球内陷3.5 ~4.5 mm者8例,复视3例,眼球向下移位2例.术中均经下睑缘睫毛下皮肤切口,骨膜下植入塑形钛网覆盖眶下壁骨折缺损区.结果 术后随访6 ~ 12个月,眼球内陷均矫正至2 mm以内,复视3例完全消失,2例眼球下移位均消失,视力无明显变化.术后无感染,植人物无脱出

  13. 钛网联合多孔聚乙烯植入治疗内壁合并下壁眼眶骨折%Titanium mesh combined with Medpor implantation in orbital reconstruction for medial and inferior orbital wall fractures

    Institute of Scientific and Technical Information of China (English)

    姜倩钰; 郭涛; 沙英虹; 韩雪梅; 史要武

    2012-01-01

    Objective To evaluate the effect of titanium mesh combined with porous polyethylene (Medpor) implantation in orbital reconstruction for medial and inferior orbital wall fractures.Methods The surgical effect of 12 cases(12 eyes) of medial and inferior orbital wall fracture patients who received titanium mesh combined with Medpor implantation for orbital wall reconstruction were analyzed retrospectively.Preoperatively,there were 10 cases with enophthalmos equal to or more than 3 mm,2 cases with enophthalmos between 2 to 3 mm,5 cases with diplopia,2 cases with apparent vertical globe dystopia.For all the cases,an inferior subciliary approach was performed,a titanium mesh plate was used for the inferior orbital wall reconstruction and Medpor was used for the medial orbital wall reconstruction or in cases with apparent enophthalmos.Results Postoperatively,after a followed up period of 3-6 monthes,the enophthalmos of all the cases was successfully corrected to less than 2mm,the preoperative diplopia disappeared in 4 cases,resolved apparently in 1 case,the vertical globe dystopia of 2 cases disappeared,and no visual acuity impairment was observed.No complication of infection,extrusion,rejection or migration of the implants occurred.Conclusion Titanium mesh combined with Medpor implantation in orbital reconstruction for medial and inferior orbital wall fractures is safe and effective,which takes the merits of both implants.%目的 探讨应用钛网联合多孔高密度聚乙烯板(Medpor)植入治疗内壁合并下壁眼眶骨折的疗效.方法 回顾性分析12例(12眼)内壁合并下壁眼眶骨折行钛网联合Medpor植入的手术效果,术前眼球内陷≥3 mm者10例,内陷2~3 mm者2例,复视5例,眼球明显下移2例,术中均经下睑缘下皮肤切口,下壁骨折区行钛网植入,内壁骨折区及眼球内陷重的行Medpor植入矫正.结果 术后随访3~6个月,眼球内陷均矫正至2 mm以内,复视完全消失4例,明显改善1例,2例眼球

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

    OpenAIRE

    Jacek Białecki; Marian Majchrzycki; Antoni Szymczak; Małgorzata Dorota Klimowicz-Bodys; Edward Wierzchoś; Krzysztof Kołomecki

    2014-01-01

    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)...

  15. Functional response of osteoblasts in functionally gradient titanium alloy mesh arrays processed by 3D additive manufacturing.

    Science.gov (United States)

    Nune, K C; Kumar, A; Misra, R D K; Li, S J; Hao, Y L; Yang, R

    2017-02-01

    We elucidate here the osteoblasts functions and cellular activity in 3D printed interconnected porous architecture of functionally gradient Ti-6Al-4V alloy mesh structures in terms of cell proliferation and growth, distribution of cell nuclei, synthesis of proteins (actin, vinculin, and fibronectin), and calcium deposition. Cell culture studies with pre-osteoblasts indicated that the interconnected porous architecture of functionally gradient mesh arrays was conducive to osteoblast functions. However, there were statistically significant differences in the cellular response depending on the pore size in the functionally gradient structure. The interconnected porous architecture contributed to the distribution of cells from the large pore size (G1) to the small pore size (G3), with consequent synthesis of extracellular matrix and calcium precipitation. The gradient mesh structure significantly impacted cell adhesion and influenced the proliferation stage, such that there was high distribution of cells on struts of the gradient mesh structure. Actin and vinculin showed a significant difference in normalized expression level of protein per cell, which was absent in the case of fibronectin. Osteoblasts present on mesh struts formed a confluent sheet, bridging the pores through numerous cytoplasmic extensions. The gradient mesh structure fabricated by electron beam melting was explored to obtain fundamental insights on cellular activity with respect to osteoblast functions. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. USE OF REPEREN POLYMER MESHES IN SURGICAL TREATMENT OF PECTUS EXCAVATUM

    Directory of Open Access Journals (Sweden)

    A. V. Krupko

    2014-01-01

    Full Text Available In patients with the I degree of pectus excavatum a retraction of the sternocostal complex is insignificant and does not influence the functional state of visceral organs. It is the elimination of a cosmetic defect that matters for such patients above all. There are various methods of aesthetic correction, still there is no consensus on how to perform an aesthetic thoracoplasty in patients with pectus excavatum. The purpose of this study was to develop a technique of aesthetic thoracoplasty with the use of Reperen polymer and to evaluate short-term results. Material and methods. From 2011 till 2013, 10 patients underwent thoracoplasty with the use of Reperen polymer meshes. All patients were male. At the time of the surgery their average age was 18.7 years (from 15 to 26 years old. The technique consists in laying molded Reperen mesh plates on the front surface of the sternocostal complex layer by layer. From 3 to 7 layers are formed. Results. The surgeries performed were successful. In all cases the postoperative period was smooth, with no complications observed. A good result accounted for 80% of the cases, a satisfactory result was observed in 20%. We did not observe any negative results. The implants installed were not removed, no excessive contouring was observed. Conclusion. A new technique of aesthetic thoracoplasty with the use of Reperen polymer plates was developed and implemented. It was found that this type of surgery is easily tolerable by patients, gives a good aesthetic result with a low risk of complications, and is characterized by a short hospital and rehabilitation period.

  17. 钛网修补颅骨缺损276例经验%Application of titanium mesh in the repair of skull defects

    Institute of Scientific and Technical Information of China (English)

    程凯敏; 黄警锐; 肖虹

    2011-01-01

    目的 分析使用钛网进行颅骨修补术后的效果和出现的特殊问题,提高手术质量.方法 276例颅骨损伤病人,其中男性212例,女性64例;年龄16~84岁,平均年龄46.3岁.手工塑型:按照骨窗大小选择稍大的二维或三维钛网,根据术者颅骨外犁在通用模具中进行手工塑型备用.数字化三维钛网预成型:术前行全头颅螺旋CT连续薄层扫描,并行颅骨三维成像.刻光盘由"钛网数字化成型机"对二维钛网进行成型加工后备用.手术按颅骨修补常规操作进行,将预成型并已经消毒的钛网按标记覆盖在骨窗上,周边选择适当的位置用配套的自攻钛钉固定牢靠,钛网中央选点用1号线悬吊8~10针.术后常规抗生素治疗,7~9d拆线,结果 大多数病人术后切口愈合良好.早期钛网手工塑型,成形效果差异较大,个别病人有翘边现象.2006年10月起使用数字化钛网成型,成型效果明显提高.颅骨修补后发生不良反应:皮瓣下积液12例,经观察全部可以自行吸收.术区积血或相临脑组织发牛迟发性血肿6例,有2例再次开颅清除血肿,取出钛网.硬膜下与蛛网膜问形成积液囊8例,经保守治疗均有不同程度吸收.翼颞窝形成增生性包块2例,经特定电磁波照射后有所吸收变小变软.钛网发生后期排异反应4例,其中3例已取出钛网,1例自动出院.结论 选择恰当的时机手术,材料的大小与形状匹配,解剖结构还原,使用钛网修补颅骨可以获得满意效果.%Objective To analyze the peculiar problems in the cranioplasty with titartium mesh, for the purpose of improving its curative effect. Methods A total of 276 patients with skull defect were enrolled, which included 212 males and 64 females with age 16 - 84 years old (mean age 46.3 years old). Largish two-dimensional or three-dimensional(3D) titanium mesh was chosen based on the bone window size and the plastotype was hand-made in the universal mold in

  18. Coating with Autologous Plasma Improves Biocompatibility of Mesh Grafts In Vitro: Development Stage of a Surgical Innovation

    Directory of Open Access Journals (Sweden)

    Holger Gerullis

    2013-01-01

    Full Text Available Purpose. To investigate mesh coating modalities with autologous blood components in a recently developed in vitro test system for biocompatibility assessment of alloplastic materials. Materials and Methods. Seven different mesh types, currently used in various indications, were randomly investigated. Meshes were coated prior to cultivation with autologous peripheral blood mononuclear cells (PBMCs, platelets, and blood plasma. Pretreated meshes were incubated over 6 weeks in a minced tissue assay, representative for fibroblasts, muscle cells, and endothelial cells originating from 10 different patients. Adherence of those tissues on the meshes was microscopically investigated and semiquantitatively assessed using a previously described scoring system. Results. Coating with peripheral blood mononuclear cells did not affect the adherence score, whereas coating with platelets and blood plasma increased the score suggesting improved biocompatibility in vitro. The previous ranking of native meshes remained consistent after coating. Conclusion. Plasma coating of meshes improves their biocompatibility score in a novel in vitro test system.

  19. Patient-Reported Outcomes in Implant-Based Breast Reconstruction Alone or in Combination with a Titanium-Coated Polypropylene Mesh - A Detailed Analysis of the BREAST-Q and Overview of the Literature.

    Science.gov (United States)

    Dieterich, M; Angres, J; Stubert, J; Stachs, A; Reimer, T; Gerber, B

    2015-07-01

    Background: Complication rates and surgical outcomes are well reported for implant-based breast reconstruction (IBBR) using supportive materials for the inferior pole of the breast. Patient-reported outcomes (PRO) are underrepresented. The aim of this study was to compare PRO in IBBR using implants alone or in combination with a synthetic mesh. Methods and Methods: PRO was measured in patients undergoing IBBR alone or in combination with a titanium-covered polypropylene mesh (TiLOOP® Bra). In this non-randomized observational trial PRO was retrospectively assessed using the validated self-reporting BREAST-Q. The raw responses of all questions applied in each domain and transformed BREAST-Q data using the Q-Score are presented. Results: Of 90 eligible women, 42 received IBBR alone and 48 received IBBR in combination with mesh. No differences in complication rates were observed. The return rate was 67.7 % and was comparable between the groups (p = 0.117). PRO revealed no differences regarding satisfaction with breast shape (p = 0.079), outcome (p = 0.604), nipple sensitivity (p = 0.502), preoperative information (p = 0.195), office staff (p = 0.462), psychosocial well-being (p = 0.370), sexual well-being (p = 0.508) and physical well-being (p = 0.654). Significant differences were noted regarding satisfaction with the surgeon (p = 0.013) and medical staff (p = 0.035) as well as the response behavior of certain questions of the sub-domains, thus helping to further stratify PRO with regards to aesthetic outcome. However, no differences were observed in the main BREAST-Q results. Conclusion: Use of the TiLOOP® Bra in IBBR results in comparable BREAST-Q scores compared with IBBR alone. Evaluating the BREAST-Q sub-domains helps to stratify PRO more profoundly and assists in interpreting the overall results and specific research questions.

  20. Titanium

    DEFF Research Database (Denmark)

    Fage, Simon W; Muris, Joris; Jakobsen, Stig S

    2016-01-01

    Exposure to titanium (Ti) from implants and from personal care products as nanoparticles (NPs) is common. This article reviews exposure sources, ion release, skin penetration, allergenic effects, and diagnostic possibilities. We conclude that human exposure to Ti mainly derives from dental...... and medical implants, personal care products, and foods. Despite being considered to be highly biocompatible relative to other metals, Ti is released in the presence of biological fluids and tissue, especially under certain circumstances, which seem to be more likely with regard to dental implants. Although...... most of the studies reviewed have important limitations, Ti seems not to penetrate a competent skin barrier, either as pure Ti, alloy, or as Ti oxide NPs. However, there are some indications of Ti penetration through the oral mucosa. We conclude that patch testing with the available Ti preparations...

  1. Disckectomy, Partial Adjacent Centrum Resection, Bone Graft with Titanium Mesh and Titanium Plate Fixation for the Treatment of Single Segment Cervical Disc Degeneration with Adjacent Vertebral Posterior Osteophyte%椎间盘及部分椎体切除加钛网植骨钛板内固定术治疗单节段颈椎椎间盘突出伴椎体后缘骨赘

    Institute of Scientific and Technical Information of China (English)

    孙继飞; 何强; 刘振利; 陈庆胜

    2012-01-01

    目的 评价颈椎椎间盘及相邻椎体部分切除加钛网植骨钛板内固定术治疗单节段颈椎椎间盘退变突出伴相邻椎体后缘骨赘的疗效. 方法 应用颈椎椎间盘及相邻椎体部分切除加钛网植骨钛板内固定术治疗单节段颈椎椎间盘退变突出伴相邻椎体后缘骨赘22例.取颈椎前路手术切口,术中仅切除突出的椎间盘及相邻椎体的1/3~ 1/2,使脊髓得到彻底的减压.再用填满碎骨的钛网植于骨缺损处加用钛板螺丝钉内固定,固定范围仅限于相邻椎体.术前和术后通过神经功能JOA评分、颈部轴性症状、颈椎动态侧位片和颈椎MRI比较临床疗效. 结果 均获随访,平均15(6 ~24)个月,术后JOA评分优良率86.4%,颈部轴性症状减轻,脊髓功能明显得到恢复.颈椎活动度良好.X线检查见钛网植骨及钛板内固定良好,未见不稳现象.MRI示颈髓压迫解除. 结论 颈椎椎间盘及相邻椎体部分切除加钛网植骨钛板内固定术治疗单节段颈椎椎间盘突出伴相邻椎体骨赘效果显著,可最大限度地保留颈椎节段的活动度.%Objective To evaluate the clinical effects of disckectomy, partial adjacent centrum resection , bone graft with titanium mesh and titanium plate fixation for the treatment of single segment cervical disc degeneration with adjacent vertebral posterior osteophyte. Methods There were 22 cases received this kind of surgical procedure. By anterior cervical incision, the herniated disc and only 1/3 to 1/2 of the adjacent vertebral body were removed for the decompression of the spinal cord. Then the titanium mesh filled with the small bones was implanted in the bone defect followed by titanium screw fixation. The fixation was limited to the adjacent vertebral bodies. Preoperative and postoperative neurological functions of the JOA score, the cervical axial symptoms, the cervical dynamic radiographs and cervical spine MRI were used to compare the clinical

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

    Science.gov (United States)

    Rosen, Michael J.; Bauer, Joel J.; Harmaty, Marco; Carbonell, Alfredo M.; Cobb, William S.; Matthews, Brent; Goldblatt, Matthew I.; Selzer, Don J.; Poulose, Benjamin K.; Hansson, Bibi M. E.; Rosman, Camiel; Chao, James J.; Jacobsen, Garth R.

    2017-01-01

    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 biologic meshes has reported chronic biomaterial infections and high hernia recurrence rates. Methods: Patients with a contaminated or clean-contaminated operative field and a hernia defect at least 9 cm2 had a biosynthetic mesh (open, sublay, retrorectus, or intraperitoneal) repair with fascial closure (n = 104). Endpoints included overall Kaplan-Meier estimates for hernia recurrence and postoperative wound infection rates at 24 months, and the EQ-5D and Short Form 12 Health Survey (SF-12). Analyses were conducted on the intent-to-treat population, and health outcome measures evaluated using paired t tests. Results: Patients had a mean age of 58 years, body mass index of 28 kg/m2, 77% had contaminated wounds, and 84% completed 24-months follow-up. Concomitant procedures included fistula takedown (n = 24) or removal of infected previously placed mesh (n = 29). Hernia recurrence rate was 17% (n = 16). At the time of CVH repair, intraperitoneal placement of the biosynthetic mesh significantly increased the risk of recurrences (P ≤ 0.04). Surgical site infections (19/104) led to higher risk of recurrence (P < 0.01). Mean 24-month EQ-5D (index and visual analogue) and SF-12 physical component and mental scores improved from baseline (P < 0.05). Conclusions: In this prospective longitudinal study, biosynthetic absorbable mesh showed efficacy in terms of long-term recurrence and quality of life for CVH repair patients and offers an alternative to biologic and permanent synthetic meshes in these complex situations. PMID:28009747

  3. 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.

    Science.gov (United States)

    Rosen, Michael J; Bauer, Joel J; Harmaty, Marco; Carbonell, Alfredo M; Cobb, William S; Matthews, Brent; Goldblatt, Matthew I; Selzer, Don J; Poulose, Benjamin K; Hansson, Bibi M E; Rosman, Camiel; Chao, James J; Jacobsen, Garth R

    2017-01-01

    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. CVH has an increased risk of postoperative infection. CVH repair with synthetic or biologic meshes has reported chronic biomaterial infections and high hernia recurrence rates. Patients with a contaminated or clean-contaminated operative field and a hernia defect at least 9 cm had a biosynthetic mesh (open, sublay, retrorectus, or intraperitoneal) repair with fascial closure (n = 104). Endpoints included overall Kaplan-Meier estimates for hernia recurrence and postoperative wound infection rates at 24 months, and the EQ-5D and Short Form 12 Health Survey (SF-12). Analyses were conducted on the intent-to-treat population, and health outcome measures evaluated using paired t tests. Patients had a mean age of 58 years, body mass index of 28 kg/m, 77% had contaminated wounds, and 84% completed 24-months follow-up. Concomitant procedures included fistula takedown (n = 24) or removal of infected previously placed mesh (n = 29). Hernia recurrence rate was 17% (n = 16). At the time of CVH repair, intraperitoneal placement of the biosynthetic mesh significantly increased the risk of recurrences (P ≤ 0.04). Surgical site infections (19/104) led to higher risk of recurrence (P < 0.01). Mean 24-month EQ-5D (index and visual analogue) and SF-12 physical component and mental scores improved from baseline (P < 0.05). In this prospective longitudinal study, biosynthetic absorbable mesh showed efficacy in terms of long-term recurrence and quality of life for CVH repair patients and offers an alternative to biologic and permanent synthetic meshes in these complex situations.

  4. Cementless Titanium Mesh Fixation of Osteoporotic Burst Fractures of the Lumbar Spine Leads to Bony Healing: Results of an Experimental Sheep Model

    Directory of Open Access Journals (Sweden)

    Anica Eschler

    2016-01-01

    Full Text Available Introduction. Current treatment strategies for osteoporotic vertebral compression fractures (VCFs focus on cement-associated solutions. Complications associated with cement application are leakage, embolism, adjacent fractures, and compromise in bony healing. This study comprises a validated VCF model in osteoporotic sheep in order to (1 evaluate a new cementless fracture fixation technique using titanium mesh implants (TMIs and (2 demonstrate the healing capabilities in osteoporotic VCFs. Methods. Twelve 5-year-old Merino sheep received ovariectomy, corticosteroid injections, and a calcium/phosphorus/vitamin D-deficient diet for osteoporosis induction. Standardized VCFs (type AO A3.1 were created, reduced, and fixed using intravertebral TMIs. Randomly additional autologous spongiosa grafting (G1 or no augmentation was performed (G2, n=6 each. Two months postoperatively, macroscopic, micro-CT and biomechanical evaluation assessed bony consolidation. Results. Fracture reduction succeeded in all cases without intraoperative complications. Bony consolidation was proven for all cases with increased amounts of callus development for G2 (58.3%. Micro-CT revealed cage integration. Neither group showed improved results with biomechanical testing. Conclusions. Fracture reduction/fixation using TMIs without cement in osteoporotic sheep lumbar VCF resulted in bony fracture healing. Intravertebral application of autologous spongiosa showed no beneficial effects. The technique is now available for clinical use; thus, it offers an opportunity to abandon cement-associated complications.

  5. Tension-free Polypropylene Mesh-related Surgical Repair for Pelvic Organ Prolapse has a Good Anatomic Success Rate but a High Risk of Complications

    Institute of Scientific and Technical Information of China (English)

    Lei Zhang; Lan Zhu; Juan Chen; Tao Xu; Jing-He Lang

    2015-01-01

    Background:Food and Drug Administration announcements have highlighted the standard rate of mesh-related complications.We aimed to report the short-term results and complications of tension-free polypropylene mesh (PROSIMATM) surgical repair of pelvic organ prolapse (POP) using the standard category (C),timing (T),and site (S) classification system.Methods:A prospective cohort study of 48 patients who underwent PROSIMATM mesh kit-related surgical repairs were followed for two years at Peking Union Medical College Hospital.Recurrence was defined as symptomatic POP quantification (POP-Q) Stage Ⅱ or higher (leading edge ≥-1 cm).The Patient Global Impression of Change Questionnaire,the Chinese version of the Pelvic Floor Impact Questionnaire short-form-7 and POP/Urinary Incontinence Sexual Questionnaire short-form-12 were used to evaluate the self-perception and sexual function of each patient.Mesh-related complications conformed to the International Urogynecological Association/International Continence Society joint terminology.The paired-sample t-test,one-way analysis of variance,Fisher's exact test,Kaplan-Meier survival analysis and log-rank test were used to analyze data.Results:All patients were followed up for≥1 2 months; 30 (62.5%) patients completed the 24 months study.We observed a 93.8% (45/48) positive anatomical outcome rate at 12 months and 90.0% (27/30) at 24 months.Recurrence most frequently involved the anterior compartment (P < 0.05).Pelvic symptoms improved significantly from baseline (P < 0.05),although the patients' impressions of change and sexual function were not satisfying.Vaginal complication was the main complication observed (35.4%,17/48).The survival analysis did not identify any relationship between vaginal complication and anatomical recurrent prolapse (POP-Q ≥ Stage Ⅱ) (P =0.653).Conclusions:Tension-free polypropylene mesh (PROSIMATM)-related surgical repair of POP has better short-term anatomical outcomes at the

  6. Effect of posterior subsidence on cervical alignment after anterior cervical corpectomy and reconstruction using titanium mesh cages in degenerative cervical disease.

    Science.gov (United States)

    Jang, Jae-Won; Lee, Jung-Kil; Lee, Jung-Heon; Hur, Hyuk; Kim, Tae-Wan; Kim, Soo-Han

    2014-10-01

    Subsidence after anterior cervical reconstruction using a titanium mesh cage (TMC) has been a matter of debate. The authors investigated and analyzed subsidence and its effect on clinical and radiologic parameters after cervical reconstruction using a TMC for degenerative cervical disease. Thirty consecutive patients with degenerative cervical spine disorders underwent anterior cervical corpectomy followed by reconstruction with TMC. Twenty-four patients underwent a single-level corpectomy, and six patients underwent a two-level corpectomy. Clinical outcomes were assessed using a Visual Analogue Scale (VAS), the Japanese Orthopedic Association (JOA) score and the Neck Disability Index (NDI). Fusion status, anterior and posterior subsidence of the TMC, segmental angle (SA) and cervical sagittal angle (CSA) were assessed by lateral and flexion-extension radiographs of the neck. The mean follow-up period was 27.6 months (range, 24 to 49 months). The VAS, NDI and JOA scores were all significantly improved at the last follow-up. No instances of radiolucency or motion-related pseudoarthrosis were detected on radiographic analysis, yielding a fusion rate of 100%. Subsidence occurred in 28 of 30 patients (93.3%). The average anterior subsidence of the cage was 1.4 ± 0.9 mm, and the average posterior subsidence was 2.9 ± 1.2 mm. The SA and CSA at the final follow-up were significantly increased toward a lordotic angle. Anterior cervical reconstruction using TMC and plating in patients with cervical degenerative disease provides good clinical and radiologic outcomes. Cage subsidence occurred frequently, especially at the posterior part of the cage. Despite the prominent posterior subsidence of the TMC, SA and CSA were improved on final follow-up radiographs, suggesting that posterior subsidence may contribute to cervical lordosis.

  7. Reconstrução de ponte nasal com tela de titânio após exérese tumoral em um cão Nasal bridge reconstruction with titanium mesh after tumor excision in a dog

    Directory of Open Access Journals (Sweden)

    Renan Marcel Krüger

    2011-03-01

    Full Text Available O presente trabalho relata o uso de tela de titânio como alternativa para reconstrução do defeito ósseo criado pela ressecção agressiva de carcinoma de células escamosas da ponte nasal em cão. Após o tratamento quimioterápico com 5-fluorouracil tópico e sistêmico associado à piroxicam para a redução da massa tumoral, foi realizada a ressecção cirúrgica da região comprometida e reparo do defeito ósseo com tela de titânio e posterior recobrimento com retalho músculo-cutâneo unipediculado de avanço. A principal complicação no período pós-operatório foi a formação de enfisema subcutâneo, controlado em três dias com drenagem do ar e aplicação de bandagens compressivas. O animal permaneceu sem sinais de recidiva por oito meses. No décimo mês pós-operatório, o paciente apresentou miíase no local da recidiva e a proprietária optou pela eutanásia. Com esse caso, foi possível concluir que a tela de titânio foi um material adequado para a reconstrução da ponte nasal, tendo como principal complicação a ocorrência de enfisema subcutâneo.This paper describes the use of titanium mesh as an alternative for reconstruction of bone defect created by resection of aggressive squamous cell carcinoma of the nasal bridge in a dog. After chemotherapy with topic and systemic 5-fluorouracil associated with piroxicam for the tumor mass reduction, it was performed a surgical resection of the affected region, repair of bone defects with titanium mesh and subsequent closing of the wound with musculocutaneous single pedicle advancement flap. The main complication in the postoperative period was the formation of subcutaneous emphysema, which was controlled in three days with air drainage and application of compression bandages. The animal remained without signs of recurrence for eight months. In the tenth month postoperatively, the patient presented myiasis in local recurrence and the owner opted for euthanasia. In this case, it

  8. Mesh implants: An overview of crucial mesh parameters

    Institute of Scientific and Technical Information of China (English)

    Lei-Ming; Zhu; Philipp; Schuster; Uwe; Klinge

    2015-01-01

    Hernia repair is one of the most frequently performed surgical interventions that use mesh implants. This article evaluates crucial mesh parameters to facilitate selection of the most appropriate mesh implant, considering raw materials, mesh composition, structure parameters and mechanical parameters. A literature review was performed using the Pub Med database. The most important mesh parameters in the selection of a mesh implant are the raw material, structural parameters and mechanical parameters, which should match the physiological conditions. The structural parameters, especially the porosity, are the most important predictors of the biocompatibility performance of synthetic meshes. Meshes with large pores exhibit less inflammatory infiltrate, connective tissue and scar bridging, which allows increased soft tissue ingrowth. The raw material and combination of raw materials of the used mesh, including potential coatings and textile design, strongly impact the inflammatory reaction to the mesh. Synthetic meshes made from innovative polymers combined with surface coating have been demonstrated to exhibit advantageous behavior in specialized fields. Monofilament, largepore synthetic meshes exhibit advantages. The value of mesh classification based on mesh weight seems to be overestimated. Mechanical properties of meshes, such as anisotropy/isotropy, elasticity and tensile strength, are crucial parameters for predicting mesh performance after implantation.

  9. The surgical stabilization of multiple rib fractures using titanium elastic nail in blunt chest trauma with acute respiratory failure.

    Science.gov (United States)

    Tarng, Yih-Wen; Liu, Yuan-Yuarn; Huang, Fong-Dee; Lin, Hsing-Lin; Wu, Tzu-Chin; Chou, Yi-Pin

    2016-01-01

    Blunt chest injuries are usually combined with multiple rib fractures and severe lung contusions. This can occasionally induce acute respiratory failure and prolong ventilations. In order to reduce the periods of ventilator dependency, we propose a less invasive method of fixing multiple rib fractures. Since October 2009, we have developed a new method to fix fractured ribs caused by blunt trauma. Rib fixations were performed using 2.0- or 2.5-mm intramedullary titanium elastic nails (TEN), with the help of video-assisted thoracoscopic surgery (VATS) and minimal thoracic incisions. All the patients' demographics and postoperative data were collected. From January 2010 to December 2012, a total of 65 patients presenting with multiple rib fractures resulting in acute respiratory failure were included in the study. Twelve patients received the new surgical fixation. Rib fixations were performed at an average of 4 days after trauma. Patients were successfully weaned off ventilators after an average of 3 days. The average length of stay in the hospital and the intensive care unit (ICU) was shorter for the patients with fixation than for nonsurgical patients. All twelve patients returned to normal daily activities and work. In the reconstruction of an injured chest wall, the VATS with TENs fixation in multiple rib fractures is feasible. This method is also effective in decreasing the length of the surgical wound. Because the structure of the chest cage is protected, the period of mechanical ventilation is shortened and the length of stay in the hospital and the ICU can be reduced.

  10. 钛网植入治疗眼眶内下壁爆裂性骨折眼球内陷%Titanium mesh implantation for the treatment of enophthalmos caused by blow-out fractures of orbital medial and inferior walls

    Institute of Scientific and Technical Information of China (English)

    于金国; 张静楷; 陈松; 韩琪; 颜华

    2015-01-01

    目的 探讨钛网植入治疗眼眶内下壁爆裂性骨折后眼球内陷的效果.方法 回顾性分析11例(11只眼)眼眶内下壁爆裂性骨折行钛网植入手术的临床资料.术前眼球内陷4.0 ~6.5mm,伴双眼复视者2例,眼球下移位者4例.手术入路为下睑缘切口联合鼻侧皮肤切口,分别于骨膜下植入钛网覆盖眶内壁及下壁骨折缺损区.结果 术后随访7~11个月,眼球内陷均矫正至1 mm以内,2例复视完全消失,4例眼球移位均完全矫正.术后无感染、植人物脱出、排斥或移位等并发症.结论 单纯应用钛网治疗眼眶内下壁爆裂性骨折引起的眼球内陷安全有效,重建眶腔特殊解剖形态、完全还纳脱出的眶内容物是治疗的关键.%Objective To evaluate the effect of titanium mesh implantation for enophthalmos secondary to blow-out fractures of orbital medial and inferior walls.Methods The surgical effects of 11 cases (11 eyes) of blow-out fractures of orbital medial and inferior walls who received titanium mesh implantation for orbital reconstruction were analyzed retrospectively.Preoperatively,all cases showed 4.0 to 6.5mm enophthalmos among whom 2 cases had diplopia and 4 cases had apparent vertical globe dystopia.For all the cases,inferior subciliary approach combined with nasal lateral approach were performed,and 2 titanium mesh plates were implanted under the periosteum to cover the area of the inferior and medial orbital wall fracture respectively in order to reconstruct the normal orbital cavity.Results Postoperatively,after a followed up period of 7-11 months,the enophthalmos of all cases was corrected to less than l mm successfully,the preoperative diplopia disappeared in all the 2 cases,the vertical globe dystopia of 4 cases disappeared totally,and no complication such as infection,extrusion,rejection or migration of the implants occurred.Conclusion Titanium mesh plates implantation only is safe and effective to correct the enophthalmos

  11. Opfront: mesh

    DEFF Research Database (Denmark)

    2015-01-01

    Mesh generation and visualization software based on the CGAL library. Folder content: drawmesh Visualize slices of the mesh (surface/volumetric) as wireframe on top of an image (3D). drawsurf Visualize surfaces of the mesh (surface/volumetric). img2mesh Convert isosurface in image to volumetric...

  12. Is the vertebral expandable prosthetic titanium rib a surgical alternative in patients with spina bifida?

    Science.gov (United States)

    Flynn, John M; Ramirez, Norman; Emans, John B; Smith, John T; Mulcahey, Mary Jane; Betz, Randal R

    2011-05-01

    Nonambulatory children with myelodysplasia are most likely to develop spinal deformity. As the deformity progresses, the overall health of the patient deteriorates. Traditional management of the deformity with fusion results in a short trunk, crankshaft deformity, and spine and lung growth inhibition. One alternative that potentially minimizes these problems is the vertebral expandable prosthetic titanium rib (VEPTR). We therefore asked whether the use of the VEPTR in immature nonambulating children with myelodysplasia with spinal deformity would (1) correct deformity; (2) allow growth; and (3) allow adequate respiratory function. We identified 20 nonambulatory patients with myelodysplasia who were part of a multicenter Investigational Device Exemption study of 214 patients treated with the VEPTR system. Demographics, standard radiographic measurements, pulmonary function parameters, and complications in 16 patients were analyzed. Average age at first surgery was 48.6 months. The minimum followup was 25 months (mean, 59 months; range, 25-164 months). The Cobb angle decreased postoperatively in nine patients, increased less than 10° in five patients, and increased less than 20° in two patients. The mean increase in thoracic spinal length (growth) by year after the initial procedure with lengthening was 0.48 cm. Ventilatory function improved in 11 patients and deteriorated in five patients. Intraoperative complications occurred in two patients. Complications directly related to the implant were seven infections and five implant migrations. Our observations suggest VEPTR is a reasonable treatment option for spinal deformity in the immature, nonambulatory myelodysplasia population correcting the spinal deformity, allowing spinal growth, and maintaining adequate respiratory function. The rate of complications is within the range reported for spinal fusion using standard approaches.

  13. 计算机辅助快速成型钛网在眼眶爆裂骨折整复中的应用%Orbital blowout fracture reconstruction using titanium mesh pre-bent with computer-aided rapid prototy-ping technology

    Institute of Scientific and Technical Information of China (English)

    张翔; 陈伟; 曹罡; 董震; 徐金科; 刘秉尧; 罗婷苑; 马娟; 张森林

    2016-01-01

    Objective This study was to evaluate the clinical outcomes of orbital blowout fracture repair using the individual titanium mesh bent by computer-aided rapid prototyping . Methods The CT imaging data of 11 cases of orbital blowout fracture were analyzed.The subciliary approach was used for the exposure of the fractures .An appropriate 3D-printed titanium mesh pre-bent by computer-aided rapid prototyping was selected and implanted according to the characteristics of a given defect .The surgical results were analyzed by evaluating diplopia , eyeball movement , enophthalmos , and the position of the titanium mesh and comparing the orbital vol-ume before and after surgery . Results All the operations were successfully accomplished .No remolding or trimming was needed for the pre-bent titanium mesh and implanted titanium mesh was tightly fixed to the orbital wall .The patients were followed up for 3 -12 months, which revealed no symptoms of diplopia in any of the patients . Volumetric analysis showed a significantly reduced orbital volume difference from (2.60 ±0.43) mL preoperatively to (-0.07 ±0.62) mL postoperatively (P<0.01).Enophthalmos was desirably correc-ted, with the enophthalmos difference decreased from (2.35 ±0.81)mm preoperatively to (-0.10 ±0.52) mm postoperatively (P<0.01).No extra-ocular muscle limitation was observed . Conclusion The individual titanium mesh bent with computer-aided rapid prototyping technology can be applied to orbital blowout fracture repair , which may achieve a high success rate of anatomic restoration of the orbital volume and effective prevention of enophthalmos .%目的:由于眶下壁和眶内侧壁的形态不规则,且衬垫的钛网通常是在术中由医师根据经验手工弯制和塑形,难以精确恢复眶壁的原有形态,故整复效果难以得到保障。本研究分析应用计算机辅助快速成型技术预弯的钛网修复眼眶爆裂骨折的临床疗效。方法根据11例眼眶爆裂骨折患

  14. Surgical treatment of traumatic eventration with polyester button and polypropylene mesh to strengthen the suture technique in equine

    OpenAIRE

    Orlandini, Carla Faria; Steiner, Denis; Boscarato, André Giarola; Gimenes, Gabriel Coelho; Alberton, Luiz Romulo

    2016-01-01

    Background Defects in the abdominal wall of horses have high relapse rate. This is mainly in lateral eventrations and hernias caused by trauma from kicks of other horses or installation structures. The eventration region normally becomes swollen and there may be complications due to intestinal loop incarceration. The surgical treatment, consisting of reconstruction of the abdominal wall, frequently require biological or synthetic materials for the reinforcement of the suture line and tension ...

  15. [A preliminary study on the mechanical characteristics of the titanium scaffolds with three-dimensional mesh structure fabricated by electron beam melting].

    Science.gov (United States)

    Yan, R Z; Li, Y F; Wang, C; Li, R X; Liu, Z W; Hu, M

    2016-11-09

    Objective: To examine the biomechanical properties of three-dimensional(3D) printed electron beam melting(EBM) Ti-6Al-4V mesh as scaffold for mandibular repairment. Methods: We fabricated Ti-6Al-4V samples of different structures with strut, sheet and 3D mesh scaffolds(a controllable diameter 0.35, 0.50, 0.70 mm, distribution density: intensive sparse) by EBM process. The mechanical properties of these structures were examined by X-ray energy dispersive spectrum(EDS), uniaxial tensile test, three-point bending test, under compression load and compared with their different microstructure and mechanical properties. Results: Compressive deformation behavior of these cellular structures exhibited brittle character that had a typical irregular plateau region in the stress-strain curves. The mesh of larger diameter(d=0.70 mm) showed higher specific strength than the meshs of small diameter(d=0.35 mm) did, and the other 3D mesh under the same condition showed identical specific stiffness. Conclusions: EBM was successfully used to fabricate novel 3D mesh Ti-6Al-4V structures for applications. By optimizing the buckling and bending deformation, Ti-6Al-4V cellular solids with high strength, low modulus. Furthermore, the results of mechanical property and chemistry composition showed that the scaffold could completely satisfy the requirement of hard tissue repairment.

  16. Computed tomography evidence of fluid in the hernia sac predicts surgical site infection following mesh repair of acutely incarcerated ventral and groin hernias.

    Science.gov (United States)

    Loftus, Tyler J; Go, Kristina L; Jordan, Janeen R; Croft, Chasen A; Smith, R Stephen; Moore, Frederick A; Efron, Philip A; Mohr, Alicia M; Brakenridge, Scott C

    2017-07-01

    Mesh placement during repair of acutely incarcerated ventral and groin hernias is associated with high rates of surgical site infection (SSI). The utility of preoperative computed tomography (CT) in this setting is unclear. We hypothesized that CT evidence of bowel wall compromise would predict SSI while accounting for physiologic parameters. We performed a 4-year retrospective cohort analysis of 50 consecutive patients who underwent mesh repair of acutely incarcerated ventral or groin hernias. We analyzed chronic disease burden, acute illness severity, CT findings, operative management, and herniorrhaphy-specific outcomes within 180 days. The primary outcome was SSI by the Centers for Disease Control and Prevention criteria. Multiple logistic regression was performed to identify independent predictors of SSI. Eighty-four percent of all patients were American Society of Anesthesiologists class III or IV, 28% were active smokers, and mean body mass index (BMI) was 35 kg/m. Fifty-four percent had ventral hernias, 40% had inguinal hernias, and 6% had femoral or combined inguinal/ femoral hernias. Seventy percent of preoperative CT scans had features suggesting bowel compromise, abdominal free fluid, or fluid in the hernia sac. Surgical site infection occurred in 32% of all patients (8% superficial, 24% deep or organ/space). The strongest predictors of SSI were CT evidence of fluid in the hernia sac (odds ratio [OR], 8.3; 95% confidence interval [CI], 1.7-41), initial heart rate 90 beats/min or greater (OR, 6.3; 95% CI, 1.1-34), and BMI 35 kg/m or greater (OR, 5.8; 95% CI, 1.2-28). Surgical site infection rates were significantly higher among patients who had CT evidence of fluid in the hernia sac (56% vs. 19%, p = 0.012). More than half of all patients with CT scan evidence of fluid in the hernia sac developed an SSI. Computed tomography evidence of fluid in the hernia sac was the strongest predictor of SSI, followed by heart rate and BMI. Together, these parameters

  17. Resultados de los primeros casos de craneoplastia con tela de titanio y colgajo galeal bipediculado postraumatismo craneano Resultados dos primeiros casos da cranioplastia com tela de titânio e retalho galeal bipediculado pós-trauma crânio-encefálico Results of first cases of craneoplasty with titanium mesh and galeal bipediculated flap after craneal trauma

    Directory of Open Access Journals (Sweden)

    L. Dos Santos Fonseca

    2010-03-01

    titânio associada ao retalho galeal bipediculado é um procedimento eficaz e viável na rede pública hospitalar.The discontinuity of skull cap bones is most frequently caused by severe crane-encephalic trauma. The repair of these deformities is known as cranioplasty. In our paper we evaluate first results of cranioplasty with titanium meshes and galeal bipediculated remnant, according to a retrospective, series of cases, one described the results of cranioplasty with titanium meshes and remnant involving 10 patients attempted from January to October 2007, after pre-surgery evaluation by computerized tomography. Ninety per cent of patients were males, with mean age equal to 29.9 years old. Mean internment time was equal to 10.3 days. There was one complication and one case of resurgery due to the blast of a mesh after four months. All patients were satisfied with surgical and esthetical results. As a conclusion, cranioplasty with titanium mesh associated to galeal bipediculated remnant if effective and viable at public hospital services.

  18. Application of individually performed titanium mesh in infraorbital wall fracture reconstruction%应用个体化预成型钛网修复眶下壁骨折的临床分析

    Institute of Scientific and Technical Information of China (English)

    孙凯建; 王春霞; 王雅文; 陈琳琳

    2016-01-01

    AlM:To discuss the application effect of individually performed titanium mesh in infraorbital wall fracture reconstruction.METHODS:Sixty-seven patients ( 67 eyes ) diagnosed as infraorbital fracture from January 2011 to February 2014 were performed reconstruction with individually performed titanium mesh. The recovery of incision, visual acuity, eyeball mobility, diplopia and proptosis were monitored by post- operation follow- up which lasted for 1a.RESULTS:No infection, titanium mesh transposition, prolapse, deformities, exclusion or ectropion were occurred in the follow-up period. The eyeball embole was less than 2mm by bilateral proptosis contrast. The diplopia in 5 eyes were disappeared in 4 and approved in one. The eyeball descent in 2 cases was disappeared. The visual acuity was the same compared with pre-operation. The rate of disappeared diplopia at primary position was 93% and improved significantly in the other 3 patients. The rate of disappeared diplopia at peripheral visual field was 86% and improved significantly in the other 2 patients.CONCLUSlON:The reconstruction effect of individually performed titanium mesh in infraorbital wall fracture was satisfied and safe.%目的::探讨个体化预成型钛网修复眶下壁骨折的应用效果。方法:对下壁眼眶骨折患者共67例67眼采用个体化预成型钛网进行手术修复,术后随访期为1a,监测切口愈合情况、视力、眼球运动度、复视及眼球突出情况。结果:术后随访期间无感染,无钛网移位、脱出、变形及排斥等并发症,无下睑外翻病例发生。眼球内陷均达到双眼球突出度对比相差小于2mm。术后随访1a,所有患者眶下壁骨折全面修复。眼球运动无受限,各方向运动到位。复视者5例中复视完全消失4例,明显改善1例,2例眼球下移者下移均消失。术后视力与术前对比无明显变化。第一眼位复视消失率为93%,另外3例患者明显改善,周

  19. 一体钛网整体修复眼眶骨折后眼球内陷的原因%Postoperative enophthalmos in inner and inferior orbital fracture repaired by titanium mesh

    Institute of Scientific and Technical Information of China (English)

    王树纲; 邹吉新; 张繁友

    2013-01-01

    目的 探讨经一体钛网材料整体修复眼眶内壁合并下壁骨折术后眼球内陷的原因.方法 眼眶内壁合并下壁骨折术后眼球内陷改善不理想6例,研究其手术方法、植入材料及影像学表现.结果 6例术前为眼球内陷3 ~4 mm,术前计算机断层成像(CT)显示骨折范围大,眶内容物大量脱出,“隅角”移位;手术中使用一体钛网材料同时修复内壁及下壁.术后残余2 mm的眼球内陷,2例复视.术后CT显示6例存在钛网后缘向筛窦移位,后部眶腔重建不理想,1例复视者存在眶内容旋转,眼外肌移位情况,1例骨膜下出血,眼球上移位.结论 眼眶内壁合并下壁骨折手术难度较大,直视下找到正常解剖标志点,采用个体化手术方案,合理选择手术材料,才能达到较好的效果.%Objective To explore the causes of postoperative enophthalmos in inner and inferior orbital fracture repaired by titanium mesh.Methods Six cases with inner and inferior orbital fracture repaired by titanium mesh were studied,whose postoperative symptoms were residual enophthalmos.Operative method,implant material,and imagining manifestation were studied.Results Preoperatively,6 cases showed 3~ 4 mm enophthalmos,CT showed fractures of orbital contents in large range,large number of prolapse,and "comer" shife.In operation,one titanium mesh was used to repair the fracture.Postoperative patients showed 2 mm enophthalmos in all these cases,and diplopia in 2 patients; postoperative CT showed the shift of titanium mesh edge to ethmoid sinus,posterior orbital reconstruction is not ideal ; in one diplopia case,CT showed rotation of orbital content and extraocular muscle transposition.Besides,subperiosteal hemorrhage and eyeball displacement were showed in the other diplopia case.Conclusion Operational difficulty in orbital fracture with inner and inferior wall is great.Normal anatomical landmark found under direct vision,individual operation scheme

  20. Preliminary report of wrapped impacted bone graft using titanium mesh for repair of large segmental bone defect%钛网包裹打压植骨修复大段骨缺损初步报告

    Institute of Scientific and Technical Information of China (English)

    殷渠东; 顾三军; 孙振中; 马运宏

    2015-01-01

    Objective To investigate the preliminary outcomes of wrapped impacted bone graft using titanium mesh for repair of large segmental bone defect. Methods From January 2009 to December 2012,6 cases of large segmental bone defect of lone bone after fractures were treated with wrapped impacted bone graft using titanium mesh to repair the defect. The location of fracture and defect:1 respective casein femur and humerus,2 respective cases in tibia and radius.The length of bone defect was from 5.2 cm to 9.0 cm with an average of 6.5cm.Fixation methods:intramedullary nail was used in 2 cases and plate in 4 cases.collateral injuries such as tendon or nerve injury could be foundin 2 cases. Cancellous bone with a volume two times than the defect bone was harvested from theposterior or/and anterior segments of the bilateral ilium etc. Titanium mesh was used and placed to wrap the defect, then the bone granules was impacted closely into the titanium mesh.The recovered length of bone defect was from 5.2 cm to 9.0 cm with an average of 6.3 cm. Results Incisions underwent primary healing. Following-up ranging from 12 to 46 months, with an average of 18 months,revealed that all fractures with bone defects healed; the clinical healing time ranged from 4.0 months to 6.5 months with an average of 5.1 months. no breakingor loosening of the fixator was noted.at the last follow-up,the function of the adjacent joints was excellent in 1 case, good in 4 cases and fair in 1 case. Conclusion Wrapped impacted bone graft using titanium mesh for repair of large segmental bone defect has advantages of bing simple, safe, fast in healing and excellent in efficacy.%目的:探讨钛网包裹打压植骨修复大段骨缺损的初步治疗效果。方法2009年1月~2012年12月,采用钛网包裹打压植骨修复6例长骨骨折后大段骨缺损。骨折骨缺损部位:股骨和肱骨各1例,胫骨、桡骨各2例。骨缺损长度5.2~9.0 cm,平均6.5 cm。固定方法:髓内钉2

  1. 个体化钛网支架复合游离皮瓣修复上颌骨缺损初步研究%Restorations of maxillary defects by individualized titanium meshes and microvascular free flaps

    Institute of Scientific and Technical Information of China (English)

    郑维银; 羊书勇; 李浩; 吴坡

    2016-01-01

    Objective To evaluate the clinical efficacy of restorations of maxillary defects by microvascular free flaps and individual titanium meshes based on 3D printed maxilla models. Methods Retrospective analysis of 18 cases with maxillary defects from 2011 to 2013 was made. For all the cases, 3D models internally fixed with titanium meshes fabricated according to preoperative CT data were implanted to support their faces, and microvascular free flaps were used to close their oral and nasal cavities. Results 4 cases used rectus abdominis muscle flaps, 6 cases forearm flaps, 3 cases lateral arm flaps, and 5 cases anterolateral thigh flaps. All flaps were a-live. Moreover, faces of all cases were symmetric, closure of oral and nasal cavities as well as maxillary sinus was complete so that all cases were able to eat through oral cavities, and their postoperative vocalization was clear. Only 2 cases with soft palate defects occa-sionally suffered from mild nasal regurgitation when having liquid diets. Conclusion Individualized 3D models and titanium meshes combined with microvascular free flaps used in restoring maxillary defects can obtain satisfactory functional and aesthetic outcomes for patients. However, the effects of closing oral and nasal cavities by free tissue flaps on the restoration of false teeth need to be further explored.%目的:探讨在3D打印上颌骨模型上预制作钛网支架复合游离皮瓣行上颌骨缺损修复的的临床疗效。方法对我院2年来治疗的18例上颌骨缺损、术中将在术前根据CT数据制作的个体化3D模型上预备的内固定钛网支架植入形成面部支撑、复合游离皮瓣关闭口鼻腔的患者进行回顾分析。结果18例患者中,应用腹直肌皮瓣4例、前臂皮瓣6例、上臂外侧皮瓣3例、股前外侧皮瓣5例,所有组织瓣均成活良好,术后面部外形对称,口鼻腔及口腔上颌窦封闭完全,均能经口腔进食,术后语音清晰,仅有2例合并

  2. 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

    2016-01-01

    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......-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...

  3. Surgical planning and microvascular reconstruction of the mandible with a fibular flap using computer-aided design, rapid prototype modelling, and precontoured titanium reconstruction plates: a prospective study.

    Science.gov (United States)

    Sieira Gil, R; Roig, A Marí; Obispo, C Arranz; Morla, A; Pagès, C Martí; Perez, J Llopis

    2015-01-01

    The standard of mandibular reconstruction has increased since the introduction of computer-assisted design (CAD) and rapid prototype modelling (RPM) for surgical planning. Between 2008 and 2013, a prospective pilot study of 20 patients was planned to compare the outcomes of patients treated by mandibular reconstruction who had CAD and RPM-guided operations using a precontoured titanium plate, with the outcomes of patients treated conventionally. We recorded the time taken for reconstruction, total operating time, and whether this type of planning could improve the results of mandibular reconstruction. We found significant differences in the incidence of dental malocclusion (p=0.03) and exposure of the titanium plate (p=0.009). The mean operating time for reconstruction in the preoperative planning group was 135 (37)min compared with 176 (58)min in the conventional group (p=0.04). Preoperative planning using CAD and RPM can increase the accuracy of microvascular mandibular reconstruction and reduce the operating time for reconstruction. Copyright © 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  4. Custom titanium sleeve for surgical treatment of mechanically assisted crevice corrosion in the well-fixed, noncontemporary stem in total hip arthroplasty

    Directory of Open Access Journals (Sweden)

    Thomas Leibiger

    2015-12-01

    Full Text Available Adverse local tissue reaction associated with total hip replacement may occur when mechanically assisted crevice corrosion occurs at metal-metal modular junctions in which at least one of the components is fabricated from cobalt-chromium alloy. Complete removal of components may be associated with significant morbidity; when components are well fixed and in acceptable position, it may be appropriate to consider modular rather than complete revision. We have diagnosed mechanically assisted crevice corrosion in total hip arthroplasty patients with noncontemporary but well-fixed femoral components and found that modular conversion to a ceramic femoral head to remove a source of CoCr corrosion and fretting products was only possible by having a custom titanium sleeve manufactured. Surgical implantation with a revision style Biolox ceramic head (CeramTec, Plochingen, Germany was then achieved.

  5. 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

    2016-01-01

    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.

  6. Breket titanium (Titanium bracket

    Directory of Open Access Journals (Sweden)

    Sianiwati Goenharto

    2005-09-01

    Full Text Available There has been a considerable discussion in the literature about corrosion and sensitivity to the nickel present in stainless steel brackets. Titanium has been heralded as a material totally compatible in the oral environment and superior in structural integrity compared to stainless steel. Many current applications in dentistry and medicine have made titanium an obvious choice for a possible substitute material. Titanium based brackets have shown excellent corrosion resistance and possessed good biocompatibility. Evaluation of titanium brackets for orthodontic therapy showed that titanium brackets were comparable to stainless steel brackets in passive and active configuration. Study about metallographic structure, hardness, bond strength to enamel substrate, etc. showed that titanium brackets exhibited a potential for clinical application. It was concluded that titanium brackets were suitable substitute for stainless steel brackets.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    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....

  8. Collagen hydrogels strengthened by biodegradable meshes are a basis for dermo-epidermal skin grafts intended to reconstitute human skin in a one-step surgical intervention.

    Science.gov (United States)

    Hartmann-Fritsch, Fabienne; Biedermann, Thomas; Braziulis, Erik; Luginbühl, Joachim; Pontiggia, Luca; Böttcher-Haberzeth, Sophie; van Kuppevelt, Toin H; Faraj, Kaeuis A; Schiestl, Clemens; Meuli, Martin; Reichmann, Ernst

    2016-01-01

    Extensive full-thickness skin loss, associated with deep burns or other traumata, represents a major clinical problem that is far from being solved. A promising approach to treat large skin defects is the use of tissue-engineered full-thickness skin analogues with nearly normal anatomy and function. In addition to excellent biological properties, such skin substitutes should exhibit optimal structural and mechanical features. This study aimed to test novel dermo-epidermal skin substitutes based on collagen type I hydrogels, physically strengthened by two types of polymeric net-like meshes. One mesh has already been used in clinical trials for treating inguinal hernia; the second one is new but consists of a FDA-approved polymer. Both meshes were integrated into collagen type I hydrogels and dermo-epidermal skin substitutes were generated. Skin substitutes were transplanted onto immuno-incompetent rats and analyzed after distinct time periods. The skin substitutes homogeneously developed into a well-stratified epidermis over the entire surface of the grafts. The epidermis deposited a continuous basement membrane and dermo-epidermal junction, displayed a well-defined basal cell layer, about 10 suprabasal strata and a stratum corneum. Additionally, the dermal component of the grafts was well vascularized. Copyright © 2012 John Wiley & Sons, Ltd.

  9. 3D 打印个性化钛网结合游离皮瓣修复上颌缺损的探索%Exploration on repairing maxillary defects by 3D printed individuation titanium mesh combined with free skin flap

    Institute of Scientific and Technical Information of China (English)

    羊书勇; 郑维银; 李晨军; 李浩; 鄢兰元; 卢艳鹏; 米增媛; 张薏

    2014-01-01

    Objective To summarize the experience of repairing maxillary defects by 3D printed individuation titanium mesh prosthesis combined with free skin flap,and analyze the indications,method,and factors affecting the success or failure of the operation. Methods From Jan. of 2013 to Dec. of the same year,3D printing technology was used to prepare the individuation titanium mesh prosthesis and repair the sophisticated maxillary defects of 12 patients combined with vascular anastomosis free skin flap. Immediate repair was provided for all patients. Results All 12 ones were successfully repaired,and their outline forms were good. Conclusion Reparation of sophisticated maxillary defects by 3D printed individuation titanium mesh prosthesis combined with free skin flap is a reasonable and effective way.%目的:总结采用3D 打印技术制备个性化钛网修复体,并结合游离皮瓣用于口腔颌面部缺损修复的经验,对这一方法的用途、应用方法、成败因素等加以分析。方法2013年1~12月,应用3D 打印技术制备个性化钛网修复体,结合血管吻合游离皮瓣修复复杂的上颌组织缺损12例,所有病例均为即刻修复。结果12例病例均修复成功,外形良好。结论采用3D 打印技术预制个性化钛网修复体,结合游离皮瓣修复上颌组织缺损,是一条合理有效的治疗途径。

  10. Evaluation of anterior cervical reconstruction with titanium mesh cages versus nano-hydroxyapatite/polyamide66 cages after 1- or 2-level corpectomy for multilevel cervical spondylotic myelopathy: a retrospective study of 117 patients.

    Directory of Open Access Journals (Sweden)

    Yuan Zhang

    Full Text Available OBJECTIVE: To retrospectively compare the efficacy of the titanium mesh cage (TMC and the nano-hydroxyapatite/polyamide66 cage (n-HA/PA66 cage for 1- or 2-level anterior cervical corpectomy and fusion (ACCF to treat multilevel cervical spondylotic myelopathy (MCSM. METHODS: A total of 117 consecutive patients with MCSM who underwent 1- or 2-level ACCF using a TMC or an n-HA/PA66 cage were studied retrospectively at a mean follow-up of 45.28 ± 12.83 months. The patients were divided into four groups according to the level of corpectomy (1- or 2-level corpectomy and cage type used (TMC or n-HA/PA66 cage. Clinical and radiological parameters were used to evaluate outcomes. RESULTS: At the one-year follow-up, the fusion rate in the n-HA/PA66 group was higher, albeit non-significantly, than that in the TMC group for both 1- and 2-level ACCF, but the fusion rates of the procedures were almost equal at the final follow-up. The incidence of cage subsidence at the final follow-up was significantly higher in the TMC group than in the n-HA/PA66 group for the 1-level ACCF (24% vs. 4%, p = 0.01, and the difference was greater for the 2-level ACCF between the TMC group and the n-HA/PA66 group (38% vs. 5%, p = 0.01. Meanwhile, a much greater loss of fused height was observed in the TMC group compared with the n-HA/PA66 group for both the 1- and 2-level ACCF. All four groups demonstrated increases in C2-C7 Cobb angle and JOA scores and decreases in VAS at the final follow-up compared with preoperative values. CONCLUSION: The lower incidence of cage subsidence, better maintenance of the height of the fused segment and similar excellent bony fusion indicate that the n-HA/PA66 cage may be a superior alternative to the TMC for cervical reconstruction after cervical corpectomy, in particular for 2-level ACCF.

  11. The use of mesh implants in vaginal prolapse surgery: Position ...

    African Journals Online (AJOL)

    the risks and benefits of surgery with mesh versus all surgical and non-surgical alternatives'. ... Johnson) or partially (Boston Scientific, CR Bard) from the market, and anecdotally the .... sacrocolpopexy (open or endoscopic). • Complications ...

  12. INCISIONAL HERNIA - ONLAY VS SUBLAY MESH HERNIOPLAS T Y

    OpenAIRE

    Ravi Kamal Kumar; Chandrakumar; Vijayalaxmi,; Thokala; Venkat Ramana

    2015-01-01

    BACKGROUND : Incisional hernia is a common surgical problem. Anatomical repair of hernia is now out of vogue. Polypropylene mesh repair has now become accepted. In open mesh repair of incisional hernia cases the site of placement of mesh is still debated. Some surgeo ns favour the onlay repair and others use sublay or retro - rectus plane for deployment of the mesh. AIM: The aim of the study is to examine the pros and cons of both the techniques and find the bett...

  13. 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)

    2015-02-27

    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.

  14. [Chest Wall Reconstruction Using Titanium Plates Sandwiched Between Sheets after Resection of Chest Wall Chondrosarcoma].

    Science.gov (United States)

    Endoh, Makoto; Oizumi, Hiroyuki; Kato, Hirohisa; Suzuki, Jun; Watarai, Hikaru; Hamada, Akira; Suzuki, Katsuyuki; Takahashi, Ai; Nakahashi, Kenta; Sugawara, Masato; Tsuchiya, Takashi; Sadahiro, Mitsuaki

    2016-07-01

    Extensive chest wall resection carries the risk of difficult reconstruction and surgical complications. We report our experience on chest wall reconstruction using titanium plates for a wide thoracic defect after tumor resection. A 74-year-old man was diagnosed with chondrosarcoma of the 6th rib on the right. He needed extensive chest wall resection because of skip lesions on 4th rib noted on operative inspection, leaving a defect measuring 33 × 20 cm. Reconstruction using 5 transverse titanium plates sandwiched between an expanded polytetrafluoroethylene patch and a polypropylene mesh sheet stabilized the chest wall. This reconstruction allowed successful separation from ventilatory support after operation. The postoperative course was uneventful, and he was discharged on postoperative day 20. The advantages of this form of reconstruction over conventional prostheses are rigidity, and stability and usability.

  15. Large Contaminated Ventral Hernia Repair Using Component Separation Technique with Synthetic Mesh

    NARCIS (Netherlands)

    Slater, N.J.; Knaapen, L.; Bökkerink, W.J.V.; Biemans, M.J.; Buyne, O.R.; Ulrich, D.J.O.; Bleichrodt, R.P.; Goor, H. van

    2015-01-01

    BACKGROUND: Large ventral hernia repair represents a major reconstructive surgical challenge, especially under contaminated conditions. Synthetic mesh is usually avoided in these circumstances because of fear of mesh infection, although evidence is outdated and does not regard new materials and

  16. Mesh network simulation

    OpenAIRE

    Pei Ping; YURY N. PETRENKO

    2015-01-01

    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...

  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

    2005-08-01

    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. Determination of residual stresses in roll compacted titanium strips

    CSIR Research Space (South Africa)

    Mothosi, KL

    2017-01-01

    Full Text Available induced during roll compaction of titanium strips were measured for strips of different densities. The different densities were achieved by rolling two different particle size (100 and 325 mesh) titanium powders varying the roll gap (0.1, 0.3 and 0.5 mm...

  19. Mesh generation in archipelagos

    NARCIS (Netherlands)

    Terwisscha van Scheltinga, A.; Myers, P.G.; Pietrzak, J.D.

    2012-01-01

    A new mesh size field is presented that is specifically designed for efficient meshing of highly irregular oceanic domains: archipelagos. The new approach is based on the standard mesh size field that uses the proximity to the nearest coastline. Here, the proximities to the two nearest coastlines

  20. Finite element mesh generation

    CERN Document Server

    Lo, Daniel SH

    2014-01-01

    Highlights the Progression of Meshing Technologies and Their ApplicationsFinite Element Mesh Generation provides a concise and comprehensive guide to the application of finite element mesh generation over 2D domains, curved surfaces, and 3D space. Organised according to the geometry and dimension of the problem domains, it develops from the basic meshing algorithms to the most advanced schemes to deal with problems with specific requirements such as boundary conformity, adaptive and anisotropic elements, shape qualities, and mesh optimization. It sets out the fundamentals of popular techniques

  1. Electrowinning molten titanium from titanium dioxide

    CSIR Research Space (South Africa)

    Van Vuuren, DS

    2005-10-01

    Full Text Available ; the high affinity of titanium for carbon, oxygen, and nitrogen; and physical and chemical properties of the different titanium oxide species when reducing titanium from Ti4+ to metallic titanium....

  2. Oral, intestinal, and skin bacteria in ventral hernia mesh implants

    Directory of Open Access Journals (Sweden)

    Odd Langbach

    2016-07-01

    Full Text Available Background: In ventral hernia surgery, mesh implants are used to reduce recurrence. Infection after mesh implantation can be a problem and rates around 6–10% have been reported. Bacterial colonization of mesh implants in patients without clinical signs of infection has not been thoroughly investigated. Molecular techniques have proven effective in demonstrating bacterial diversity in various environments and are able to identify bacteria on a gene-specific level. Objective: The purpose of this study was to detect bacterial biofilm in mesh implants, analyze its bacterial diversity, and look for possible resemblance with bacterial biofilm from the periodontal pocket. Methods: Thirty patients referred to our hospital for recurrence after former ventral hernia mesh repair, were examined for periodontitis in advance of new surgical hernia repair. Oral examination included periapical radiographs, periodontal probing, and subgingival plaque collection. A piece of mesh (1×1 cm from the abdominal wall was harvested during the new surgical hernia repair and analyzed for bacteria by PCR and 16S rRNA gene sequencing. From patients with positive PCR mesh samples, subgingival plaque samples were analyzed with the same techniques. Results: A great variety of taxa were detected in 20 (66.7% mesh samples, including typical oral commensals and periodontopathogens, enterics, and skin bacteria. Mesh and periodontal bacteria were further analyzed for similarity in 16S rRNA gene sequences. In 17 sequences, the level of resemblance between mesh and subgingival bacterial colonization was 98–100% suggesting, but not proving, a transfer of oral bacteria to the mesh. Conclusion: The results show great bacterial diversity on mesh implants from the anterior abdominal wall including oral commensals and periodontopathogens. Mesh can be reached by bacteria in several ways including hematogenous spread from an oral site. However, other sites such as gut and skin may also

  3. A comparative study of postoperative complications of lightweight mesh and conventional prolene mesh in Lichtenstein hernia repair

    Directory of Open Access Journals (Sweden)

    Gugri Mukthinath

    2016-06-01

    Full Text Available Background: Inguinal hernia repair is the most frequently performed operation in any general surgical unit. The complications of using the mesh has been the rationale to examine the role of mesh in hernia repair in detail and to begin investigating the biocompatibility of different mesh modifications and to challenge old mesh concepts. Therefore the present study is undertaken to compare the lightweight mesh (Ultrapro with conventional prolene mesh in lichtenstein hernia repair. Methods: Thirty one patients with primary unilateral inguinal hernia was subjected either to lightweight mesh Lichtenstein's hernioplasty or standard prolene mesh Lichtenstein's hernioplasty. The patients were followed in the surgical OPD at 1 month, 6 months and 1 year for time taken to return to normal activities, chronic groin pain, foreign body sensation, seroma formation and recurrence. Results: Chronic pain among patients in standard prolene mesh group at 1 month, 6 month, and 1 year follow up was seen in 45.2%, 16% and 3.2% of the patients respectively, in light weight mesh group patients at 1 month, 6 month and 1 year follow up was 32.2%, 6.4% and none at one year respectively. Foreign body sensation in the light weight mesh group is significantly less compared to patients in standard prolene mesh group. Time taken to return to work was relatively shorter among patients in Light weight mesh group. There was no recurrence in both groups. Conclusion: Light weight mesh is an ideal choice in Lichenstein's hernioplasty whenever feasible. [Int J Res Med Sci 2016; 4(6.000: 2130-2134

  4. Laparoscopic sacrocolpopexy versus transvaginal mesh for recurrent pelvic organ prolapse.

    Science.gov (United States)

    Iglesia, Cheryl B; Hale, Douglass S; Lucente, Vincent R

    2013-03-01

    Both expert surgeons agree with the following: (1) Surgical mesh, whether placed laparoscopically or transvaginally, is indicated for pelvic floor reconstruction in cases involving recurrent advanced pelvic organ prolapse. (2) Procedural expertise and experience gained from performing a high volume of cases is fundamentally necessary. Knowledge of outcomes and complications from an individual surgeon's audit of cases is also needed when discussing the risks and benefits of procedures and alternatives. Yet controversy still exists on how best to teach new surgical techniques and optimal ways to efficiently track outcomes, including subjective and objective cure of prolapse as well as perioperative complications. A mesh registry will be useful in providing data needed for surgeons. Cost factors are also a consideration since laparoscopic and especially robotic surgical mesh procedures are generally more costly than transvaginal mesh kits when operative time, extra instrumentation and length of stay are included. Long-term outcomes, particularly for transvaginal mesh procedures, are lacking. In conclusion, all surgery poses risks; however, patients should be made aware of the pros and cons of various routes of surgery as well as the potential risks and benefits of using mesh. Surgeons should provide patients with honest information about their own experience implanting mesh and also their experience dealing with mesh-related complications.

  5. ON MOBILE MESH NETWORKS

    OpenAIRE

    2015-01-01

    With the advances in mobile computing technologies and the growth of the Net, mobile mesh networks are going through a set of important evolutionary steps. In this paper, we survey architectural aspects of mobile mesh networks and their use cases and deployment models. Also, we survey challenging areas of mobile mesh networks and describe our vision of promising mobile services. This paper presents a basic introductory material for Masters of Open Information Technologies Lab, interested in m...

  6. Delaunay mesh generation

    CERN Document Server

    Cheng, Siu-Wing; Shewchuk, Jonathan

    2013-01-01

    Written by authors at the forefront of modern algorithms research, Delaunay Mesh Generation demonstrates the power and versatility of Delaunay meshers in tackling complex geometric domains ranging from polyhedra with internal boundaries to piecewise smooth surfaces. Covering both volume and surface meshes, the authors fully explain how and why these meshing algorithms work.The book is one of the first to integrate a vast amount of cutting-edge material on Delaunay triangulations. It begins with introducing the problem of mesh generation and describing algorithms for constructing Delaunay trian

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

    Directory of Open Access Journals (Sweden)

    Joshua A. Cohn

    2016-09-01

    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.

  8. Open preperitoneal groin hernia repair with mesh

    DEFF Research Database (Denmark)

    Andresen, Kristoffer; Rosenberg, Jacob

    2017-01-01

    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......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...

  9. Laparoscopic-assisted Ventral Hernia Repair: Primary Fascial Repair with Polyester Mesh versus Polyester Mesh Alone.

    Science.gov (United States)

    Karipineni, Farah; Joshi, Priya; Parsikia, Afshin; Dhir, Teena; Joshi, Amit R T

    2016-03-01

    Laparoscopic-assisted ventral hernia repair (LAVHR) with mesh is well established as the preferred technique for hernia repair. We sought to determine whether primary fascial closure and/or overlap of the mesh reduced recurrence and/or complications. We conducted a retrospective review on 57 LAVHR patients using polyester composite mesh between August 2010 and July 2013. They were divided into mesh-only (nonclosure) and primary fascial closure with mesh (closure) groups. Patient demographics, prior surgical history, mesh overlap, complications, and recurrence rates were compared. Thirty-nine (68%) of 57 patients were in the closure group and 18 (32%) in the nonclosure group. Mean defect sizes were 15.5 and 22.5 cm(2), respectively. Participants were followed for a mean of 1.3 years [standard deviation (SD) = 0.7]. Recurrence rates were 2/39 (5.1%) in the closure group and 1/18 (5.6%) in the nonclosure group (P = 0.947). There were no major postoperative complications in the nonclosure group. The closure group experienced four (10.3%) complications. This was not a statistically significant difference (P = 0.159). The median mesh-to-hernia ratio for all repairs was 15.2 (surface area) and 3.9 (diameter). Median length of stay was 14.5 hours (1.7-99.3) for patients with nonclosure and 11.9 hours (6.9-90.3 hours) for patients with closure (P = 0.625). In conclusion, this is one of the largest series of LAVHR exclusively using polyester dual-sided mesh. Our recurrence rate was about 5 per cent. Significant mesh overlap is needed to achieve such low recurrence rates. Primary closure of hernias seems less important than adequate mesh overlap in preventing recurrence after LAVHR.

  10. 2D Mesh Manipulation

    Science.gov (United States)

    2011-11-01

    triangles in two dimensions and tetrahedra ( tets ) in three dimensions. There are many other ways to discretize a region using unstructured meshes, but this...The boundary points associated with the airfoil surface were moved, but all of the interior points remained stationary , which resulted in a mesh

  11. An Adaptive Mesh Algorithm: Mapping the Mesh Variables

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-25

    Both thermodynamic and kinematic variables must be mapped. The kinematic variables are defined on a separate kinematic mesh; it is the duel mesh to the thermodynamic mesh. The map of the kinematic variables is done by calculating the contributions of kinematic variables on the old thermodynamic mesh, mapping the kinematic variable contributions onto the new thermodynamic mesh and then synthesizing the mapped kinematic variables on the new kinematic mesh. In this document the map of the thermodynamic variables will be described.

  12. The “Pelvic Harness”: a skeletonized mesh implant for safe pelvic floor reconstruction

    OpenAIRE

    Sumerova Natalia; Neuman Menahem; Krissi Haim; Pushkar Dmitri

    2016-01-01

    ABSTRACT Objectives To evaluate the feasibility, safety and surgical results of skeletonized mesh implants to form a pelvic harness for pelvic floor reconstruction surgery. Study design Patients with advanced pelvic floor prolapse were enrolled to this study. Study model was a kit mesh, reduced to 75% of the original surface area by cutting out mesh material from the central mesh body. Patients were evaluated at the end of the 1st and 6th post-operative months and interviewed at the study...

  13. Implants for surgery -- Metallic materials -- Part 3: Wrought titanium 6-aluminium 4-vanadium alloy

    CERN Document Server

    International Organization for Standardization. Geneva

    1996-01-01

    Specifies the characteristics of, and corresponding test methods for, the wrought titanium alloy known as titanium 6-aluminium 4-vanadium alloy (Ti 6-Al 4-V alloy) for use in the manufacture of surgical implants.

  14. Wireless mesh networks

    CERN Document Server

    Held, Gilbert

    2005-01-01

    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

  15. Current developments in hernia repair; meshes, adhesives, and tacking.

    Science.gov (United States)

    Powell, Benjamin S; Voeller, Guy R

    2010-10-01

    Open and laparoscopic hernia surgery continues to evolve with new products allowing surgeons multiple choices in treating their patients. The evolution towards tension-free techniques in dealing with hernias requires that today's surgeons know the options available in meshes as well as fixation methods in order to have the best outcomes. In recent years, there has been a rapid expansion in the number of meshes available. Currently, there are numerous uncoated, coated, and biologic meshes in production that can be used in hernia repair. This paper will focus on the latest developments in coated meshes that allow for intra-abdominal placement as well as the different types of biologic meshes and their typical uses. Tacking devices for laparoscopic hernia repair now come in titanium as well as absorbable devices. AbsorbaTack™ (Covidien, Norwalk, CT) and Sorbafix™ (Davol, Warwick, RI) are two of the newest absorbable tacking devices thought to possibly benefit patients with decreased pain and long-term complications as compared with their titanium counterparts. Adhesives continue to be used more and more for hernia repair, especially in inguinal and paraesophageal hernia repairs. Tissucol™/Tisseel™ (Baxter, Deerfield, IL) and Evicel™ (Ethicon, Somerville, NJ) are two types of fibrin glues that are available for use in hernia repair. Practitioners using these biologic adhesives think there is less pain compared with tacking.

  16. Polygon mesh processing

    CERN Document Server

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

    2010-01-01

    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,

  17. Geometrically Consistent Mesh Modification

    KAUST Repository

    Bonito, A.

    2010-01-01

    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.

  18. Risk factors and management of vaginal mesh erosion after pelvic organ prolapse surgery.

    Science.gov (United States)

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

    2017-04-01

    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.

  19. Titanium Alloys

    Directory of Open Access Journals (Sweden)

    Mark T. Whittaker

    2015-08-01

    Full Text Available Although originally discovered in the 18th century [1], the titanium industry did not experience any significant advancement until the middle of the 20th century through the development of the gas turbine engine [2]. Since then, the aerospace sector has dominated worldwide titanium use with applications in both engines and airframe structures [3]. The highly desirable combination of properties, which include excellent corrosion resistance, favourable strength to weight ratios, and an impressive resistance to fatigue, has led to an extensive range of applications [4], with only high extraction and processing costs still restricting further implementation. [...

  20. 钛网结合异体骨移植联合人骨形成蛋白与自体骨移植在种植前牙槽嵴骨增量中的应用对比%Comparison of Application of Titanium Mesh Combined with Allograft Combined with Human Bone Morphogenetic Protein and Autogenous Bone Transplantation in Alveolar Bone Augmentation

    Institute of Scientific and Technical Information of China (English)

    崔延军; 王红光; 程汇

    2015-01-01

    Objective To compare the application of titanium mesh combined with allograft combined with human bone morphogenetic protein and autogenous bone transplantation in alveolar bone augmentation.Methods A total of 46 cases receiving anterior implant plus alveolar bone increment admitted to Tianmen City First People′s Hospital from Jan.2008 to Dec.2011 were randomly divided into two groups according to random-number table method,group A(n =23) using titanium mesh combined with allograft combined with human bone morphogenetic protein,while group B (n =23) using autogenous bone graft.The alveolar ridge width,the incremental effects and postoperative bone implant stability were compared before and after surgery.Results Postoperative average alveolar ridge width of group A was significantly higher than that of group B [(6.9 ±0.5) mm vs (5.6 ±0.3) mm,P <0.01]; the cure rate of group A was 94.1%,of group B was 60.0%,and the clinical efficacy of group A was better than group B with statistically significant difference (P <0.05); no-loosening rate after 4 months implant was 91.2% in group A,50.6% in group B,the sta-bility of group A was much better than group B,with statistically significant difference(P <0.05).Conclu-sion Titanium mesh combined with allogeneic bone graft combined with human bone morphogenetic protein can significantly increase patient alveolar bone mass and help to stabilize the implant after surgery .%目的:比较钛网结合异体骨移植联合人骨形成蛋白与自体骨移植在种植前牙槽嵴骨增量中的应用效果。方法将2008年1月至2011年12月天门市第一人民医院收治的46例前牙种植并行牙槽嵴骨增量的患者依据随机数字表法分为两组:A 组23例,采用钛网结合异体骨移植联合人骨形成蛋白的方法;B 组23例,采用自体骨移植的方法。比较两组患者手术前后牙槽嵴宽度、骨增量效果及术后种植体稳定性。结果术后 A 组牙槽嵴

  1. 数字化塑型钛网颅骨修补对颅骨缺损患者颅内压、脑血流动力学及神经功能康复的影响%Changes of intracranial pressure, cerebral hemodynamic parameters and neuro-rehabilitation in adult patients after cranioplasty reconstruction with digital shaping titanium mesh

    Institute of Scientific and Technical Information of China (English)

    罗晟; 何永生; 陈隆益; 黄光富

    2015-01-01

    Objective To investigate the appropriate time of the skull reconstruction of skull defect,and explore the changes of intracmnial pressure,cerebral hemodynamic parameters,clinical symptoms and signs before and after cranioplasty with digital shaping titanium mesh.Methods The clinical data included parameter variations of noninvasive intracranial pressure (ICP),cerebral blood flow velocity,and improvement of skull defect syndrome and cognitive function were retrospectivly analyzed in 69 patients with skull defect received cranioplasty with digital shaping titanium mesh in our hospital from June 2009 to May 2014.The preoperative ICP less than 80 mmH2O was recorded in 53 patients and that more than or equal to 80 mmH2O was recorded in 16 patients.The interval time from the skull defects to cranioplasty was as follows:11 patients were within 3-6 months,25 were in 6-9 months,24 were in 9-12 months,and 9 were more than one year.Results The ICP after cranioplasty was in the normal range,which was statistically different as compared with that before cranioplasty (P<0.05).The mean blood flow velocity two weeks after cranioplasty was improved significantly as compared with that before cranioplasty (P<0.05).All 69 patients were recovered well postoperatively;14 patients with preoperative sensory and movement disorders got improvement of different degrees after cranioplasty;in the four patients with epilepsy,three were seizure-free,and the left one had obviously reduced epileptic seizure;two patients with speech disorders got improvement postoperatively.Skull defect syndrome symptoms in the 54 patients were disappeared.Significant differences of Glasgow outcome scale (GOS) and function independent measurement (FIM) scores were noted between before cranioplasty and three months after cranioplasty (2.48±0.67 vs.3.56±0.35;77.91±10.32 vs.93.78±6.51;P<0.05).The GOS and FIM scores in patients performed cranioplasty at early stage (interval time from the skull defects to

  2. 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

    2010-06-01

    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

  3. 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)

    2015-09-30

    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.

  4. Cosmology on a Mesh

    CERN Document Server

    Gill, S P D; Gibson, B K; Flynn, C; Ibata, R A; Lewis, G F; Gill, Stuart P.D.; Knebe, Alexander; Gibson, Brad K.; Flynn, Chris; Ibata, Rodrigo A.; Lewis, Geraint F.

    2002-01-01

    An adaptive multi grid approach to simulating the formation of structure from collisionless dark matter is described. MLAPM (Multi-Level Adaptive Particle Mesh) is one of the most efficient serial codes available on the cosmological 'market' today. As part of Swinburne University's role in the development of the Square Kilometer Array, we are implementing hydrodynamics, feedback, and radiative transfer within the MLAPM adaptive mesh, in order to simulate baryonic processes relevant to the interstellar and intergalactic media at high redshift. We will outline our progress to date in applying the existing MLAPM to a study of the decay of satellite galaxies within massive host potentials.

  5. Development of oral and extra-oral endosseous craniofacial implants by using a mesh structure for connective tissue attachment.

    Science.gov (United States)

    Mita, Atsushi; Yagihara, Atsushi; Wang, Wei; Takakuda, Kazuo

    2014-03-19

    Connective tissue attachment to a mesh structure incorporated on the surface of oral implants and extra-oral endosseous craniofacial implants (EOECI) was investigated. Two types of implants were prepared: TI and TI-Mesh. TI was composed of an upper and a lower component, both comprised of a titanium cylinder, which could be connected using a titanium screw. The composition of the TIMesh was similar, but the lower cylinder had a lateral groove that was covered with a titanium mesh. In animal experiments performed using rat calvaria, the lower component was first implanted and was left submerged for 3 weeks, then the upper component was mounted percutaneously. After an additional 2 weeks, each implant and the surrounding tissues were harvested and evaluated. Histological observations revealed collagen fibers originating from surrounding hypodermal tissues anchored to the mesh structures of the TI-Mesh whereas no such collagen fibers were observed around TI. Significantly greater values of the attachment strength, the thickness of the dermal tissue, the thickness of hypodermal tissue, and the attachment lengths were observed in TI-Mesh than those of TI. Thus connective tissue attachment with collagen fibers anchored to the mesh was achieved by incorporating mesh structures into the percutaneously placed implants.

  6. Isotopic Implicit Surface Meshing

    NARCIS (Netherlands)

    Boissonnat, Jean-Daniel; Cohen-Steiner, David; Vegter, Gert

    2004-01-01

    This paper addresses the problem of piecewise linear approximation of implicit surfaces. We first give a criterion ensuring that the zero-set of a smooth function and the one of a piecewise linear approximation of it are isotopic. Then, we deduce from this criterion an implicit surface meshing algor

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

    Directory of Open Access Journals (Sweden)

    Dällenbach P

    2015-04-01

    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

  8. Advanced Automatic Hexahedral Mesh Generation from Surface Quad Meshes

    OpenAIRE

    Kremer, Michael; Bommes, David; Lim, Isaak; Kobbelt, Leif

    2013-01-01

    International audience; A purely topological approach for the generation of hexahedral meshes from quadrilateral surface meshes of genus zero has been proposed by M. Müller-Hannemann: in a first stage, the input surface mesh is reduced to a single hexahedron by successively eliminating loops from the dual graph of the quad mesh; in the second stage, the hexahedral mesh is constructed by extruding a layer of hexahedra for each dual loop from the first stage in reverse elimination order. In th...

  9. Instant Abdominal Wall Reconstruction with Biologic Mesh following Resection of Locally Advanced Colonic Cancer

    Directory of Open Access Journals (Sweden)

    Oskay Kaya

    2012-01-01

    Full Text Available We present a case of immediate abdominal wall reconstruction with biologic mesh following the resection of locally advanced colonic cancer. The tumor in the right colon did not respond to neoadjuvant chemotherapy. Surgical enbloc excision, including excision of the invasion in the abdominal wall, was achieved, and the defect was reconstructed with porcine dermal collagen mesh. The patient was discharged with no complication, and adaptation of the mesh was excellent at the six-month followup.

  10. Partial colpocleisis for the treatment of sacrocolpopexy mesh erosions.

    Science.gov (United States)

    Quiroz, Lieschen H; Gutman, Robert E; Fagan, Matthew J; Cundiff, Geoffrey W

    2008-02-01

    The purpose of this study is to describe the outcomes of partial colpocleisis for mesh erosions after sacrocolpopexy. We retrospectively report our surgical management of mesh erosion after sacrocolpopexy. Between 1998 and 2006, we performed 499 sacral colpopexies and treated 21 patients for mesh erosion, including three referrals. Mean (range) time to diagnosis was 10.3 months (1-49). Grafts materials included: Mersilene (13), Prolene (7), and Pelvicol (1). Surgical outcomes were available for 19 patients. Ten (48%) patients were cured by the initial partial colpocleisis, while nine (45%) required a second or third (2, 10%) vaginal operation. All of the second and third vaginal excisions failed. Eight patients had an abdominal excision, and two patients required a second abdominal procedure. The success rate for the first and second abdominal resections was 38% (3/8) and 100% (2/2). Abdominal surgeries had higher blood loss (84 vs 378 cc, p = 0.012) longer hospitalization (outpatient vs 4.2 days p = 0.001), and additional morbidity (18.6%). Potential contributing factors to surgical failure were the presence of Actinomyces and current smoking. We recommend initial transvaginal mesh resection with partial colpocleisis for synthetic mesh erosions after sacrocolpopexy. Vaginal failures may be better served by an abdominal excision. Potential contributors to failure include current smoking and the presence of Actinomyces.

  11. Application of Orion anterior plate combined with titanium mesh and bone graft in the treatment of unstable cervical spondylosis%Orion钢板结合钛网植骨在不稳定型颈椎疾病中的应用

    Institute of Scientific and Technical Information of China (English)

    崔德铮

    2010-01-01

    目的:总结分析钛网结合Orion钢板内固定治疗不稳定型颈椎疾病的临床效果.方法:由作者检索1990/2008 PubMed数据及万方数据库有关Orion钢板结合钛网植骨治疗不稳定型颈椎疾病方面的文献,英文检索词为"cervical vertebrae,Orion anterior plate,titanium mesh,spinal fusion",中文检索词为"颈椎,Orion前路钢板,钛网,脊柱融合".排除重复性研究.计算机初检得到54篇文献,根据纳入标准保留13篇进一步归纳总结.结果:Orion颈椎前路钢板联合钛网植骨在治疗不稳定型颈椎疾病时可以重建颈椎前柱,有效保持颈椎的生理弯曲和椎间隙的高度,防止远期颈椎的不稳定和后凸畸形,提升椎间孔的高度和容量促进神经根症状的恢复,同时避免了自体骨移植时的供骨区的并发症,较传统的自体骨有着突出的优点,而带锁钢板又可有效避免滑脱所造成的后果,弥补了单独应用钛网在颈椎后伸运动时的不稳定现象,使各个方面的稳定性得到了加强,是一种较为理想的颈椎前路内固定方法.结论:应用Orion颈椎前路钢板内固定结合钛网植骨治疗不稳定型颈椎疾病是一种较为理想的颈椎前路内固定方法.

  12. Large Contaminated Ventral Hernia Repair Using Component Separation Technique with Synthetic Mesh

    NARCIS (Netherlands)

    Slater, N.J.; Knaapen, L.; Bökkerink, W.J.V.; Biemans, M.J.; Buyne, O.R.; Ulrich, D.J.O.; Bleichrodt, R.P.; Goor, H. van

    2015-01-01

    BACKGROUND: Large ventral hernia repair represents a major reconstructive surgical challenge, especially under contaminated conditions. Synthetic mesh is usually avoided in these circumstances because of fear of mesh infection, although evidence is outdated and does not regard new materials and tech

  13. Risk factors and management of vaginal mesh erosion after pelvic organ prolapse surgery

    Directory of Open Access Journals (Sweden)

    Yung-Wen Cheng

    2017-04-01

    Conclusion: 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.

  14. Large inatrabdominal meshes at laparoscopic insicional hernia repair, tricks and tips

    Directory of Open Access Journals (Sweden)

    V. Santa María

    2014-11-01

    Full Text Available In conducting a laparoscopic incisional hernia repair when is necessary to place a mesh larger than 10 cm diameter, introducing it into the abdominal cavity becomes difficult. The aim of this paper is to present a technique that improves and standardizes the placement of large intra-abdominal mesh, thus achieving a more neat and safe surgical technique for the patient.

  15. Efficient Packet Forwarding in Mesh Network

    OpenAIRE

    Soumen Kanrar

    2012-01-01

    Wireless Mesh Network (WMN) is a multi hop low cost, with easy maintenance robust network providing reliable service coverage. WMNs consist of mesh routers and mesh clients. In this architecture, while static mesh routers form the wireless backbone, mesh clients access the network through mesh routers as well as directly meshing with each other. Different from traditional wireless networks, WMN is dynamically self-organized and self-configured. In other words, the nodes in the mesh network au...

  16. Metal-mesh lithography.

    Science.gov (United States)

    Tang, Zhao; Wei, Qingshan; Wei, Alexander

    2011-12-01

    Metal-mesh lithography (MML) is a practical hybrid of microcontact printing and capillary force lithography that can be applied over millimeter-sized areas with a high level of uniformity. MML can be achieved by blotting various inks onto substrates through thin copper grids, relying on preferential wetting and capillary interactions between template and substrate for pattern replication. The resulting mesh patterns, which are inverted relative to those produced by stenciling or serigraphy, can be reproduced with low micrometer resolution. MML can be combined with other surface chemistry and lift-off methods to create functional microarrays for diverse applications, such as periodic islands of gold nanorods and patterned corrals for fibroblast cell cultures.

  17. Numerical assessment of bone remodeling around conventionally and early loaded titanium and titanium-zirconium alloy dental implants.

    Science.gov (United States)

    Akça, Kıvanç; Eser, Atılım; Çavuşoğlu, Yeliz; Sağırkaya, Elçin; Çehreli, Murat Cavit

    2015-05-01

    The aim of this study was to investigate conventionally and early loaded titanium and titanium-zirconium alloy implants by three-dimensional finite element stress analysis. Three-dimensional model of a dental implant was created and a thread area was established as a region of interest in trabecular bone to study a localized part of the global model with a refined mesh. The peri-implant tissues around conventionally loaded (model 1) and early loaded (model 2) implants were implemented and were used to explore principal stresses, displacement values, and equivalent strains in the peri-implant region of titanium and titanium-zirconium implants under static load of 300 N with or without 30° inclination applied on top of the abutment surface. Under axial loading, principal stresses in both models were comparable for both implants and models. Under oblique loading, principal stresses around titanium-zirconium implants were slightly higher in both models. Comparable stress magnitudes were observed in both models. The displacement values and equivalent strain amplitudes around both implants and models were similar. Peri-implant bone around titanium and titanium-zirconium implants experiences similar stress magnitudes coupled with intraosseous implant displacement values under conventional loading and early loading simulations. Titanium-zirconium implants have biomechanical outcome comparable to conventional titanium implants under conventional loading and early loading.

  18. Parallel Adaptive Mesh Refinement

    Energy Technology Data Exchange (ETDEWEB)

    Diachin, L; Hornung, R; Plassmann, P; WIssink, A

    2005-03-04

    As large-scale, parallel computers have become more widely available and numerical models and algorithms have advanced, the range of physical phenomena that can be simulated has expanded dramatically. Many important science and engineering problems exhibit solutions with localized behavior where highly-detailed salient features or large gradients appear in certain regions which are separated by much larger regions where the solution is smooth. Examples include chemically-reacting flows with radiative heat transfer, high Reynolds number flows interacting with solid objects, and combustion problems where the flame front is essentially a two-dimensional sheet occupying a small part of a three-dimensional domain. Modeling such problems numerically requires approximating the governing partial differential equations on a discrete domain, or grid. Grid spacing is an important factor in determining the accuracy and cost of a computation. A fine grid may be needed to resolve key local features while a much coarser grid may suffice elsewhere. Employing a fine grid everywhere may be inefficient at best and, at worst, may make an adequately resolved simulation impractical. Moreover, the location and resolution of fine grid required for an accurate solution is a dynamic property of a problem's transient features and may not be known a priori. Adaptive mesh refinement (AMR) is a technique that can be used with both structured and unstructured meshes to adjust local grid spacing dynamically to capture solution features with an appropriate degree of resolution. Thus, computational resources can be focused where and when they are needed most to efficiently achieve an accurate solution without incurring the cost of a globally-fine grid. Figure 1.1 shows two example computations using AMR; on the left is a structured mesh calculation of a impulsively-sheared contact surface and on the right is the fuselage and volume discretization of an RAH-66 Comanche helicopter [35]. Note the

  19. Mesh Algorithms for PDE with Sieve I: Mesh Distribution

    Directory of Open Access Journals (Sweden)

    Matthew G. Knepley

    2009-01-01

    Full Text Available We have developed a new programming framework, called Sieve, to support parallel numerical partial differential equation(s (PDE algorithms operating over distributed meshes. We have also developed a reference implementation of Sieve in C++ as a library of generic algorithms operating on distributed containers conforming to the Sieve interface. Sieve makes instances of the incidence relation, or arrows, the conceptual first-class objects represented in the containers. Further, generic algorithms acting on this arrow container are systematically used to provide natural geometric operations on the topology and also, through duality, on the data. Finally, coverings and duality are used to encode not only individual meshes, but all types of hierarchies underlying PDE data structures, including multigrid and mesh partitions. In order to demonstrate the usefulness of the framework, we show how the mesh partition data can be represented and manipulated using the same fundamental mechanisms used to represent meshes. We present the complete description of an algorithm to encode a mesh partition and then distribute a mesh, which is independent of the mesh dimension, element shape, or embedding. Moreover, data associated with the mesh can be similarly distributed with exactly the same algorithm. The use of a high level of abstraction within the Sieve leads to several benefits in terms of code reuse, simplicity, and extensibility. We discuss these benefits and compare our approach to other existing mesh libraries.

  20. Corset neophallic musculoplasty with a mesh endoprosthesis

    Directory of Open Access Journals (Sweden)

    V. V. Mikhailichenko

    2014-12-01

    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.

  1. Corset neophallic musculoplasty with a mesh endoprosthesis

    Directory of Open Access Journals (Sweden)

    V. V. Mikhailichenko

    2014-01-01

    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.

  2. Opportunities in the electrowinning of molten titanium from titanium dioxide

    CSIR Research Space (South Africa)

    Van Vuuren, DS

    2005-10-01

    Full Text Available ; the high affinity of titanium for carbon, oxygen, and nitrogen; and physical and chemical properties of the different titanium oxide species when reducing titanium from Ti4+ to metallic titanium....

  3. toolkit computational mesh conceptual model.

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-03-01

    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.

  4. Scar endometriosis developing after an umbilical hernia repair with mesh.

    Science.gov (United States)

    Majeski, James; Craggie, James

    2004-05-01

    A 44-year-old female was initially evaluated for a 3-cm umbilical hernia, which developed after a laparoscopic myomectomy performed seven years prior. The umbilical hernia was repaired using a synthetic mesh. Eight months after the umbilical hernia repair, the patient returned with chronic pain in a 3-cm raised mass originating from the umbilical hernia repair incision. The mass and mesh were surgically removed. The umbilical fascial defect was repaired with a primary fascia-to-fascia closure and the umbilicus was reconstructed from adjacent skin. The mass was found histologically to be endometriosis and fascial scarring with a foreign body reaction to synthetic mesh. Umbilical endometriosis developed either from peritoneal endometrial seeding from a laparoscopic myomectomy or from metaplasia of multipotential cells, which developed into endometriosis due to inflammatory stimulation by the synthetic mesh. Synthetic mesh probably should be avoided in the surgical repair of a laparoscopically caused umbilical hernia in a premenopausal female especially if there is a history of pelvic endometriosis.

  5. Gossiping on meshes and tori

    OpenAIRE

    Sibeyn, J.; Rao, P; Juurlink, B.

    1996-01-01

    Algorithms for performing gossiping on one- and higher dimensional meshes are presented. As a routing model, we assume the practically important worm-hole routing. For one-dimensional arrays and rings, we give a novel lower bound and an asymptotically optimal gossiping algorithm for all choices of the parameters involved. For two-dimensional meshes and tori, several simple algorithms composed of one-dimensional phases are presented. For an important range of packet and mesh sizes it gives cle...

  6. 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)

    2016-06-21

    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

  7. Synthesized Optimization of Triangular Mesh

    Institute of Scientific and Technical Information of China (English)

    HU Wenqiang; YANG Wenyu

    2006-01-01

    Triangular mesh is often used to describe geometric object as computed model in digital manufacture, thus the mesh model with both uniform triangular shape and excellent geometric shape is expected. But in fact, the optimization of triangular shape often is contrary with that of geometric shape. In this paper, one synthesized optimizing algorithm is presented through subdividing triangles to achieve the trade-off solution between the geometric and triangular shape optimization of mesh model. The result mesh with uniform triangular shape and excellent topology are obtained.

  8. Surface meshing with curvature convergence

    KAUST Repository

    Li, Huibin

    2014-06-01

    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.

  9. Initial outcomes of laparoscopic paraesophageal hiatal hernia repair with mesh.

    Science.gov (United States)

    Gebhart, Alana; Vu, Steven; Armstrong, Chris; Smith, Brian R; Nguyen, Ninh T

    2013-10-01

    The use of mesh in laparoscopic paraesophageal hiatal hernia repair (LHR) may reduce the risk of late hernia recurrence. The aim of this study was to evaluate initial outcomes and recurrence rate of 92 patients who underwent LHR reinforced with a synthetic bioabsorbable mesh. Surgical approaches included LHR and Nissen fundoplication (n = 64), LHR without fundoplication (n = 10), reoperative LHR (n = 9), LHR with a bariatric operation (n = 6), and emergent LHR (n = 3). The mean length of hospital stay was 2 ± 3 days (range, 1 to 30 days). There were no conversions to open laparotomy and no intraoperative complications. One of 92 patients (1.1%) required intensive care unit stay. The 90-day mortality was zero. Minor complications occurred in 3.3 per cent, major complications in 2.2 per cent, and late complications in 5.5 per cent of patients. There were no perforations or early hernia recurrence. The 30-day reoperation rate was 1.1 per cent. For patients with available 1-year follow-up, the overall recurrence rate was 18.5 per cent with a mean follow-up of 30 months (range, 12 to 51 months). LHR repair with mesh is associated with low perioperative morbidity and no mortality. The use of bioabsorbable mesh appears to be safe with no early hiatal hernia recurrence or late mesh erosion. Longer follow-up is needed to determine the long-term rate of hernia recurrence associated with LHR with mesh.

  10. Laparoscopic sacrocolpopexy: how low does the mesh go?

    Science.gov (United States)

    Wong, V; Guzman Rojas, R; Shek, K L; Chou, D; Moore, K H; Dietz, H P

    2017-03-01

    Laparoscopic sacrocolpopexy is becoming an increasingly popular surgical approach for repair of apical vaginal prolapse. The aim of this study was to document the postoperative anterior mesh position after laparoscopic sacrocolpopexy and to investigate the relationship between mesh location and anterior compartment support. This was an external audit of patients who underwent laparoscopic sacrocolpopexy for apical prolapse ≥ Stage 2 or advanced prolapse ≥ Stage 3, between January 2005 and June 2012. All patients were assessed with a standardized interview, clinical assessment using the International Continence Society Pelvic Organ Prolapse quantification and four-dimensional transperineal ultrasound to evaluate pelvic organ support and mesh location. Mesh position was assessed with respect to the symphysis pubis whilst distal mesh mobility was assessed using the formula √[(XValsalva - Xrest )(2) + (YValsalva - Yrest )(2) ], where X is the horizontal distance and Y is the vertical distance between the mesh and the inferior symphyseal margin, measured at rest and on Valsalva. Ninety-seven women were assessed at a mean follow-up of 3.01 (range, 0.13-6.87) years after laparoscopic sacrocolpopexy, 88% (85/97) of whom considered themselves to be cured or improved, and none had required reoperation. On clinical examination, prolapse recurrence in the apical compartment was not diagnosed in any patient; however, 60 (62%) had recurrence in the anterior compartment and 43 (44%) in the posterior compartment. On ultrasound examination, mesh was visualized in the anterior compartment in 60 patients. Both mesh position and mobility on Valsalva were significantly associated with recurrent cystocele on clinical and on ultrasound assessment (all P < 0.01). For every mm that the mesh was located further from the bladder neck on Valsalva, the likelihood of cystocele recurrence increased by 6-7%. At an average follow-up of 3 years, laparoscopic sacrocolpopexy was highly

  11. Titanium and titanium alloys fundamentals and applications

    CERN Document Server

    Peters, Manfred

    2003-01-01

    This handbook is an excellent reference for materials scientists and engineers needing to gain more knowledge about these engineering materials. Following introductory chapters on the fundamental materials properties of titanium, readers will find comprehensive descriptions of the development, processing and properties of modern titanium alloys. There then follows detailed discussion of the applications of titanium and its alloys in aerospace, medicine, energy and automotive technology.

  12. Mesh Algorithms for PDE with Sieve I: Mesh Distribution

    CERN Document Server

    Knepley, Matthew G

    2009-01-01

    We have developed a new programming framework, called Sieve, to support parallel numerical PDE algorithms operating over distributed meshes. We have also developed a reference implementation of Sieve in C++ as a library of generic algorithms operating on distributed containers conforming to the Sieve interface. Sieve makes instances of the incidence relation, or \\emph{arrows}, the conceptual first-class objects represented in the containers. Further, generic algorithms acting on this arrow container are systematically used to provide natural geometric operations on the topology and also, through duality, on the data. Finally, coverings and duality are used to encode not only individual meshes, but all types of hierarchies underlying PDE data structures, including multigrid and mesh partitions. In order to demonstrate the usefulness of the framework, we show how the mesh partition data can be represented and manipulated using the same fundamental mechanisms used to represent meshes. We present the complete des...

  13. Prevention of Adhesion to Prosthetic Mesh

    Science.gov (United States)

    van ’t Riet, Martijne; de Vos van Steenwijk, Peggy J.; Bonthuis, Fred; Marquet, Richard L.; Steyerberg, Ewout W.; Jeekel, Johannes; Bonjer, H. Jaap

    2003-01-01

    Objective To assess whether use of antiadhesive liquids or coatings could prevent adhesion formation to prosthetic mesh. Summary Background Data Incisional hernia repair frequently involves the use of prosthetic mesh. However, concern exists about development of adhesions between viscera and the mesh, predisposing to intestinal obstruction or enterocutaneous fistulas. Methods In 91 rats, a defect in the muscular abdominal wall was created, and mesh was fixed intraperitoneally to cover the defect. Rats were divided in five groups: polypropylene mesh only (control group), addition of Sepracoat or Icodextrin solution to polypropylene mesh, Sepramesh (polypropylene mesh with Seprafilm coating), and Parietex composite mesh (polyester mesh with collagen coating). Seven and 30 days postoperatively, adhesions were assessed and wound healing was studied by microscopy. Results Intraperitoneal placement of polypropylene mesh was followed by bowel adhesions to the mesh in 50% of the cases. A mean of 74% of the mesh surface was covered by adhesions after 7 days, and 48% after 30 days. Administration of Sepracoat or Icodextrin solution had no influence on adhesion formation. Coated meshes (Sepramesh and Parietex composite mesh) had no bowel adhesions. Sepramesh was associated with a significant reduction of the mesh surface covered by adhesions after 7 and 30 days. Infection was more prevalent with Parietex composite mesh, with concurrent increased mesh surface covered by adhesions after 30 days (78%). Conclusions Sepramesh significantly reduced mesh surface covered by adhesions and prevented bowel adhesion to the mesh. Parietex composite mesh prevented bowel adhesions as well but increased infection rates in the current model. PMID:12496539

  14. Risk Factors for Mesh Exposure after Transvaginal Mesh Surgery

    Institute of Scientific and Technical Information of China (English)

    Ke Niu; Yong-Xian Lu; Wen-Jie Shen; Ying-Hui Zhang; Wen-Ying Wang

    2016-01-01

    Background:Mesh exposure after surgery continues to be a clinical challenge for urogynecological surgeons.The purpose of this study was to explore the risk factors for polypropylene (PP) mesh exposure after transvaginal mesh (TVM) surgery.Methods:This study included 195 patients with advanced pelvic organ prolapse (POP),who underwent TVM from January 2004to December 2012 at the First Affiliated Hospital of Chinese PLA General Hospital.Clinical data were evaluated including patient's demography,TVM type,concomitant procedures,operation time,blood loss,postoperative morbidity,and mesh exposure.Mesh exposure was identified through postoperative vaginal examination.Statistical analysis was performed to identify risk factors for mesh exposure.Results:Two-hundred and nine transvaginal PP meshes were placed,including 194 in the anterior wall and 15 in the posterior wall.Concomitant tension-free vaginal tape was performed in 61 cases.The mean follow-up time was 35.1 ± 23.6 months.PP mesh exposure was identified in 32 cases (16.4%),with 31 in the anterior wall and 1 in the posterior wall.Significant difference was found in operating time and concomitant procedures between exposed and nonexposed groups (F =7.443,P =0.007;F =4.307,P =0.039,respectively).Binary logistic regression revealed that the number of concomitant procedures and operation time were risk factors for mesh exposure (P =0.001,P =0.043).Conclusion:Concomitant procedures and increased operating time increase the risk for postoperative mesh exposure in patients undergoing TVM surgery for POP.

  15. Skull Bone Defects Reconstruction with Custom-Made Titanium Graft shaped with Electron Beam Melting Technology: Preliminary Experience in a Series of Ten Patients.

    Science.gov (United States)

    Francaviglia, Natale; Maugeri, Rosario; Odierna Contino, Antonino; Meli, Francesco; Fiorenza, Vito; Costantino, Gabriele; Giammalva, Roberto Giuseppe; Iacopino, Domenico Gerardo

    2017-01-01

    Cranioplasty represents a challenge in neurosurgery. Its goal is not only plastic reconstruction of the skull but also to restore and preserve cranial function, to improve cerebral hemodynamics, and to provide mechanical protection of the neural structures. The ideal material for the reconstructive procedures and the surgical timing are still controversial. Many alloplastic materials are available for performing cranioplasty and among these, titanium still represents a widely proven and accepted choice. The aim of our study was to present our preliminary experience with a "custom-made" cranioplasty, using electron beam melting (EBM) technology, in a series of ten patients. EBM is a new sintering method for shaping titanium powder directly in three-dimensional (3D) implants. To the best of our knowledge this is the first report of a skull reconstruction performed by this technique. In a 1-year follow-up no postoperative complications have been observed and good clinical and esthetic outcomes were achieved. Costs higher than those for other types of titanium mesh, a longer production process, and the greater expertise needed for this technique are compensated by the achievement of most complex skull reconstructions with a shorter operative time.

  16. Reconstructive laparoscopic prolapse surgery to avoid mesh erosions

    Directory of Open Access Journals (Sweden)

    Devassy, Rajesh

    2013-09-01

    Full Text Available Introduction: The objective of the study is to examine the efficacy of the purely laparoscopic reconstructive management of cystocele and rectocele with mesh, to avoid the risk of erosion by the graft material, a well known complication in vaginal mesh surgery. Material and methods: We performed a prospective, single-case, non-randomized study in 325 patients who received laparoscopic reconstructive management of pelvic organe prolaps with mesh. The study was conducted between January 2004 and December 2012 in a private clinic in India. The most common prolapse symptoms were reducible vaginal lump, urinary stress incontinence, constipation and flatus incontinence, sexual dysfunction and dypareunia. The degree e of the prolaps was staged according to POPQ system. The approach was purely laparoscopic and involved the use of polypropylene (Prolene or polyurethane with activated regenerated cellulose coating (Parietex mesh. Results: The mean age was 55 (30–80 years and the most of the patients were multiparous (272/325. The patients received a plastic correction of the rectocele only (138 cases, a cystocele and rectocele (187 cases with mesh. 132 patients had a concomitant total hysterectomy; in 2 cases a laparoscopic supracervical hysterectomy was performed and 190 patients had a laparoscopic colposuspension. The mean operation time was 82.2 (60–210 minutes. The mean follow up was 3.4 (3–5 years. Urinary retention developed in 1 case, which required a new laparoscopical intervention. Bladder injury, observed in the same case was in one session closed with absorbable suture. There were four recurrences of the rectocele, receiving a posterior vaginal colporrhaphy. Erosions of the mesh were not reported or documented. Conclusion: The pure laparoscopic reconstructive management of the cystocele and rectocele with mesh seems to be a safe and effective surgical procedure potentially avoiding the risk of mesh erosions.

  17. Parameterization for fitting triangular mesh

    Institute of Scientific and Technical Information of China (English)

    LIN Hongwei; WANG Guojin; LIU Ligang; BAO Hujun

    2006-01-01

    In recent years, with the development of 3D data acquisition equipments, the study on reverse engineering has become more and more important. However, the existing methods for parameterization can hardly ensure that the parametric domain is rectangular, and the parametric curve grid is regular. In order to overcome these limitations, we present a novel method for parameterization of triangular meshes in this paper. The basic idea is twofold: first, because the isotherms in the steady temperature do not intersect with each other, and are distributed uniformly, no singularity (fold-over) exists in the parameterization; second, a 3D harmonic equation is solved by the finite element method to obtain the steady temperature field on a 2D triangular mesh surface with four boundaries. Therefore, our proposed method avoids the embarrassment that it is impossible to solve the 2D quasi-harmonic equation on the 2D triangular mesh without the parametric values at mesh vertices. Furthermore, the isotherms on the temperature field are taken as a set of iso-parametric curves on the triangular mesh surface. The other set of iso-parametric curves can be obtained by connecting the points with the same chord-length on the isotherms sequentially. The obtained parametric curve grid is regular, and distributed uniformly, and can map the triangular mesh surface to the unit square domain with boundaries of mesh surface to boundaries of parametric domain, which ensures that the triangular mesh surface or point cloud can be fitted with the NURBS surface.

  18. Guaranteed-Quality Triangular Meshes

    Science.gov (United States)

    1989-04-01

    Defense Ad, : ed Research P: jects Pgency or the U.S- Gower ment° iI Guaranteed-Quality Triangular Meshes DTIC ELECTE L. Paul Chew* JUL 1419891 TR 89-983 S... Wittchen , M. S. Shephard, K. R. Grice, and M. A. Yerry, Robust, geometrically based, automatic two-dimensional mesh generation, International Journal for

  19. An Improved Moving Mesh Algorithm

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    we consider an iterative algorithm of mesh optimization for finite element solution, and give an improved moving mesh strategy that reduces rapidly the complexity and cost of solving variational problems.A numerical result is presented for a 2-dimensional problem by the improved algorithm.

  20. Chinese titanium industry

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>The effects of the financial crisis on the titanium industry are visible: investment plans for titanium smelting and processing have basically come to a halt in 2009, and projects under construction were also delayed. However, the

  1. Adaptive and Unstructured Mesh Cleaving

    Science.gov (United States)

    Bronson, Jonathan R.; Sastry, Shankar P.; Levine, Joshua A.; Whitaker, Ross T.

    2015-01-01

    We propose a new strategy for boundary conforming meshing that decouples the problem of building tetrahedra of proper size and shape from the problem of conforming to complex, non-manifold boundaries. This approach is motivated by the observation that while several methods exist for adaptive tetrahedral meshing, they typically have difficulty at geometric boundaries. The proposed strategy avoids this conflict by extracting the boundary conforming constraint into a secondary step. We first build a background mesh having a desired set of tetrahedral properties, and then use a generalized stenciling method to divide, or “cleave”, these elements to get a set of conforming tetrahedra, while limiting the impacts cleaving has on element quality. In developing this new framework, we make several technical contributions including a new method for building graded tetrahedral meshes as well as a generalization of the isosurface stuffing and lattice cleaving algorithms to unstructured background meshes. PMID:26137171

  2. Abortion - surgical

    Science.gov (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. ...

  3. Streaming Compression of Hexahedral Meshes

    Energy Technology Data Exchange (ETDEWEB)

    Isenburg, M; Courbet, C

    2010-02-03

    We describe a method for streaming compression of hexahedral meshes. Given an interleaved stream of vertices and hexahedral our coder incrementally compresses the mesh in the presented order. Our coder is extremely memory efficient when the input stream documents when vertices are referenced for the last time (i.e. when it contains topological finalization tags). Our coder then continuously releases and reuses data structures that no longer contribute to compressing the remainder of the stream. This means in practice that our coder has only a small fraction of the whole mesh in memory at any time. We can therefore compress very large meshes - even meshes that do not file in memory. Compared to traditional, non-streaming approaches that load the entire mesh and globally reorder it during compression, our algorithm trades a less compact compressed representation for significant gains in speed, memory, and I/O efficiency. For example, on the 456k hexahedra 'blade' mesh, our coder is twice as fast and uses 88 times less memory (only 3.1 MB) with the compressed file increasing about 3% in size. We also present the first scheme for predictive compression of properties associated with hexahedral cells.

  4. Titanium Carbide-Graphite Composites

    Science.gov (United States)

    1991-11-08

    titanium carbide , titanium carbide with free graphite, titanium carbide /vanadium carbide alloy with free graphite, and titanium carbide with...from melts. The test pins were drawn across hot pressed titanium carbide wear plates with 5 newtons of normal force. The lowest friction coefficient at...22 C was 0.12 obtained with pure titanium carbide . The lowest friction coefficient at 900 C was 0.19 obtained with titanium carbide with boron and

  5. Mesh Adaptation and Shape Optimization on Unstructured Meshes Project

    Data.gov (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...

  6. Nanowire mesh solar fuels generator

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Peidong; Chan, Candace; Sun, Jianwei; Liu, Bin

    2016-05-24

    This disclosure provides systems, methods, and apparatus related to a nanowire mesh solar fuels generator. In one aspect, a nanowire mesh solar fuels generator includes (1) a photoanode configured to perform water oxidation and (2) a photocathode configured to perform water reduction. The photocathode is in electrical contact with the photoanode. The photoanode may include a high surface area network of photoanode nanowires. The photocathode may include a high surface area network of photocathode nanowires. In some embodiments, the nanowire mesh solar fuels generator may include an ion conductive polymer infiltrating the photoanode and the photocathode in the region where the photocathode is in electrical contact with the photoanode.

  7. Prosthetic mesh "slim-cigarette like" for laparoscopic repair of ventral hernias: a new technique without transabdominal fixation sutures.

    Science.gov (United States)

    Canton, S A; Merigliano, S; Pasquali, C

    2016-06-01

    Prosthetic mesh rolled up and fixed with stitches like a slim cigarette ("slim-mesh") for laparoscopic ventral hernia (VH) repair is an new technique which allows an easy intraperitoneally introduction, distension and circumferential fixation of a prosthetic mesh without transabdominal fixation sutures even for meshes larger than 16 cm up to 30 cm for the "slim-mesh" repair of wide ventral hernias. We report the technique of laparoscopic repair of VH with "slim-mesh". This technique enables an easy intra-peritoneally introduction of the mesh through the trocar because it reduces consistently its size, it allows a rapid intra-abdominal handling of the mesh and a fast and easy fixation for VH repair. The average time of surgery with "slim-mesh" for treatment of all 28 VH was 97 min ranging from 57 to 160 min. The average time for the repair of the 24 VH smaller than 10 cm was 91 and 135 min for the four VH larger than 10-22 cm. This new surgical technique leads to a reduction of surgical risks avoiding the use of transfascial sutures with the associated complications. This new surgical procedure in our experience is fast, safe, simple and also easily reproducible by surgeons in laparoscopic training. This technique may be used in wide VH (larger than 10-22 cm) that generally require open surgery.

  8. Spectroscopic and ultrastructural analysis of fluorhydroxyapatite-coated titanium plates

    Energy Technology Data Exchange (ETDEWEB)

    Martini, D.; Ottani, V.; Ruggeri, A. [Bologna Univ. (Italy). Dipt. di Scienze Anatomiche e Fisiopatologia dell' Apparato Locomotore; Raspanti, M. [Insubria Univ. (Italy). Dipt. di Scienze Cliniche e Biologiche; Monti, P.; Taddei, P.; Tinti, A.; Fragnano, C. [Bologna Univ. (Italy). Dipt. di Biochimica ' G. Moruzzi'

    2001-07-01

    This study aimed to describe the chemical, physical and morphological features of the surface of titanium plates coated with porous titanium and fluorhydroxyapatite for surgical implantation. Although the plasma flame spray coating process partially altered the original chemical and physical characteristics of the coatings, the surface morphology of the coated plates seems very favourable for bone integration of the implant. Immersion in simulated body fluid for ten weeks failed to disclose signs of implant dissolution or impaired surface composition. (orig.)

  9. Mersiline mesh in premaxillary augmentation.

    Science.gov (United States)

    Foda, Hossam M T

    2005-01-01

    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.

  10. An in vitro study assessing the effect of mesh morphology and suture fixation on bacterial adherence.

    Science.gov (United States)

    Sanders, D; Lambie, J; Bond, P; Moate, R; Steer, J A

    2013-12-01

    Prosthetic infections, although relatively uncommon in hernia surgery, are a source of considerable morbidity and cost. The aims of this experimental study were to assess the influence of the morphological properties of the mesh on bacterial adherence in vitro. The morphological properties assessed were the polymer type, filament type, filament diameter, mesh weight, mean pore size, and the addition of silver chlorhexidine and titanium coatings. In addition, the study assessed the effect on bacterial adherence of adding a commonly used suture to the mesh and compared adherence rates to self-gripping mesh that does not require suture fixation. Eight commercially sourced flat hernia meshes with different material characteristics were included in the study. These were Prolene(®) (Ethicon(®)), DualMesh(®) (Gore(®)), DualMesh(®) Plus (Gore(®)), Parietex™ ProGrip (Covidien™), TiMesh(®) Light (GfE Medical), Bard(®) Soft Mesh (Bard(®)), Vypro(®) (Ethicon(®)), and Omyra(®) (Braun(®)). Individual meshes were inoculated with Staphylococcus epidermidis and Staphylococcus aureus with a bacterial inoculum of 10(2) bacteria. To assess the effect of suture material on bacterial adhesion, a sterile piece of commonly used monofilament suture material (2.0 Prolene(®), ZB370 Ethicon(®)) was sutured to selected meshes (chosen to represent different commonly used polymers and/or the presence of an antibacterial coating). Inoculated meshes were incubated for 18 h in tryptone soy broth and then analysed using scanning electron microscopy. A previously validated method for enumeration of bacteria using automated stage movement electron microscopy was used for direct bacterial counting. The final fraction of the bacteria adherent to the mesh was compared between the meshes and for each morphological variable. One-way analysis of variance (ANOVA) was performed on the bacterial counts. Tukey's test was used to determine the difference between the different biomaterials in

  11. GENERATION OF IRREGULAR HEXAGONAL MESHES

    Directory of Open Access Journals (Sweden)

    Vlasov Aleksandr Nikolaevich

    2012-07-01

    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.

  12. Image-driven mesh optimization

    Energy Technology Data Exchange (ETDEWEB)

    Lindstrom, P; Turk, G

    2001-01-05

    We describe a method of improving the appearance of a low vertex count mesh in a manner that is guided by rendered images of the original, detailed mesh. This approach is motivated by the fact that greedy simplification methods often yield meshes that are poorer than what can be represented with a given number of vertices. Our approach relies on edge swaps and vertex teleports to alter the mesh connectivity, and uses the downhill simplex method to simultaneously improve vertex positions and surface attributes. Note that this is not a simplification method--the vertex count remains the same throughout the optimization. At all stages of the optimization the changes are guided by a metric that measures the differences between rendered versions of the original model and the low vertex count mesh. This method creates meshes that are geometrically faithful to the original model. Moreover, the method takes into account more subtle aspects of a model such as surface shading or whether cracks are visible between two interpenetrating parts of the model.

  13. Method and system for mesh network embedded devices

    Science.gov (United States)

    Wang, Ray (Inventor)

    2009-01-01

    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.

  14. Late mesh rejection as a complication to transabdominal preperitoneal laparoscopic hernia repair

    DEFF Research Database (Denmark)

    Hofbauer, C; Andersen, P V; Juul, P;

    1998-01-01

    BACKGROUND: The use of a mesh in transabdominal preperitoneal laparoscopic hernia repair (TAPP) caries the risk of late rejection or infectious complications related to the mesh. The aim of this study was to describe the extent of these complications. METHODS: We performed a retrospective study...... repair had been done. CONCLUSION: Late mesh rejection is a potential complication of TAPP and has to be considered when choosing the surgical method of hernia repair....... of 500 consecutive patients with TAPP for inguinal hernia. RESULTS: Late mesh rejection was observed in three patients at 5-19 months after surgery. The mesh was removed via a suprapubic midline incision. At 3-4 month's follow-up, none of the patients had recurrence of the hernia, even though no hernia...

  15. 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)

    2015-06-01

    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 or .merge) can be used as “mesh” input for any of the mesh tools discussed in this manual.

  16. Surgical Assisting

    Science.gov (United States)

    ... Insert and remove Foley urinary bladder catheter Place pneumatic tourniquet Confirm procedure with surgeon Drape patient within ... Technology and Surgical Assisting (NBSTSA) offers the CertifiedSurgical First Assistant (CSFA) credential, and the National Surgical Assistant ...

  17. Mesh refinement strategy for optimal control problems

    OpenAIRE

    Paiva, Luis Tiago; Fontes, Fernando,

    2013-01-01

    International audience; Direct methods are becoming the most used technique to solve nonlinear optimal control problems. Regular time meshes having equidistant spacing are frequently used. However, in some cases these meshes cannot cope accurately with nonlinear behavior. One way to improve the solution is to select a new mesh with a greater number of nodes. Another way, involves adaptive mesh refinement. In this case, the mesh nodes have non equidistant spacing which allow a non uniform node...

  18. Effect of whitening toothpaste on titanium and titanium alloy surfaces

    National Research Council Canada - National Science Library

    Faria, Adriana Cláudia Lapria; Bordin, Angelo Rafael de Vito; Pedrazzi, Vinícius; Rodrigues, Renata Cristina Silveira; Ribeiro, Ricardo Faria

    2012-01-01

    .... Whitening toothpastes with peroxides are available for patients with high aesthetic requirements, but the effect of whitening toothpastes on titanium surfaces is not yet known, although titanium...

  19. Osteoblast functions in functionally graded Ti-6Al-4 V mesh structures.

    Science.gov (United States)

    Nune, K C; Kumar, A; Misra, R D K; Li, S J; Hao, Y L; Yang, R

    2016-03-01

    We describe here the combined efforts of engineering and biological sciences as a systemic approach to fundamentally elucidate osteoblast functions in functionally graded Ti-6Al-4 V mesh structures in relation to uniform/monolithic mesh arrays. First, the interconnecting porous architecture of functionally graded mesh arrays was conducive to cellular functions including attachment, proliferation, and mineralization. The underlying reason is that the graded fabricated structure with cells seeded from the large pore size side provided a channel for efficient transfer of nutrients to other end of the structure (small pore size), leading to the generation of mineralized extracellular matrix by differentiating pre-osteoblasts. Second, a comparative and parametric study indicated that gradient mesh structure had a pronounced effect on cell adhesion and mineralization, and strongly influenced the proliferation phase. High intensity and near-uniform distribution of proteins (actin and vinculin) on struts of the gradient mesh structure (cells seeded from large pore side) implied signal transduction during cell adhesion and was responsible for superior cellular activity, in comparison to the uniform mesh structure and non-porous titanium alloy. Cells adhered to the mesh struts by forming a sheet, bridging the pores through numerous cytoplasmic extensions, in the case of porous mesh structures. Intercellular interaction in porous structures provided a pathway for cells to communicate and mature to a differentiated phenotype. Furthermore, the capability of cells to migrate through the interconnecting porous architecture on mesh structures led to colonization of the entire structure. Cells were embedded layer-by-layer in the extracellular matrix as the matrix mineralized. The outcomes of the study are expected to address challenges associated with the treatment of segmental bone defects and bone-remodeling through favorable modulation of cellular response. Moreover, the study

  20. Cell adhesion on NiTi thin film sputter-deposited meshes

    Energy Technology Data Exchange (ETDEWEB)

    Loger, K. [Inorganic Functional Materials, Institute for Materials Science, Faculty of Engineering, University of Kiel (Germany); Engel, A.; Haupt, J. [Department of Cardiovascular Surgery, University Hospital of Schleswig-Holstein, Kiel (Germany); Li, Q. [Biocompatible Nanomaterials, Institute for Materials Science, Faculty of Engineering, University of Kiel (Germany); Lima de Miranda, R. [Inorganic Functional Materials, Institute for Materials Science, Faculty of Engineering, University of Kiel (Germany); ACQUANDAS GmbH, Kiel (Germany); Quandt, E. [Inorganic Functional Materials, Institute for Materials Science, Faculty of Engineering, University of Kiel (Germany); Lutter, G. [Department of Cardiovascular Surgery, University Hospital of Schleswig-Holstein, Kiel (Germany); Selhuber-Unkel, C. [Biocompatible Nanomaterials, Institute for Materials Science, Faculty of Engineering, University of Kiel (Germany)

    2016-02-01

    Scaffolds for tissue engineering enable the possibility to fabricate and form biomedical implants in vitro, which fulfill special functionality in vivo. In this study, free-standing Nickel–Titanium (NiTi) thin film meshes were produced by means of magnetron sputter deposition. Meshes contained precisely defined rhombic holes in the size of 440 to 1309 μm{sup 2} and a strut width ranging from 5.3 to 9.2 μm. The effective mechanical properties of the microstructured superelastic NiTi thin film were examined by tensile testing. These results will be adapted for the design of the holes in the film. The influence of hole and strut dimensions on the adhesion of sheep autologous cells (CD133 +) was studied after 24 h and after seven days of incubation. Optical analysis using fluorescence microscopy and scanning electron microscopy showed that cell adhesion depends on the structural parameters of the mesh. After 7 days in cell culture a large part of the mesh was covered with aligned fibrous material. Cell adhesion is particularly facilitated on meshes with small rhombic holes of 440 μm{sup 2} and a strut width of 5.3 μm. Our results demonstrate that free-standing NiTi thin film meshes have a promising potential for applications in cardiovascular tissue engineering, particularly for the fabrication of heart valves. - Highlights: • Freestanding NiTi thin film scaffolds were fabricated with magnetron sputtering process. • Effective mechanical properties of NiTi scaffolds can be adapted by the mesh structure parameters. • Cell adhesion on the NiTi thin film scaffold is controlled by the structure parameters of the mesh. • Cells strongly adhere after seven days and form a confluent layer on the mesh.

  1. Connectivity editing for quadrilateral meshes

    KAUST Repository

    Peng, Chihan

    2011-12-12

    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.

  2. Connectivity editing for quadrilateral meshes

    KAUST Repository

    Peng, Chihan

    2011-12-01

    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.

  3. Mesh Router Nodes placement in Rural Wireless Mesh Networks

    OpenAIRE

    Ebongue, Jean Louis Fendji Kedieng; Thron, Christopher; Nlong, Jean Michel

    2015-01-01

    The problem of placement of mesh router nodes in Wireless Mesh Networks is known to be a NP hard problem. In this paper, the problem is addressed under a constraint of network model tied to rural regions where we usually observe low density and sparse population. We consider the area to cover as decomposed into a set of elementary areas which can be required or optional in terms of coverage and where a node can be placed or not. We propose an effective algorithm to ensure the coverage. This a...

  4. Efficient Packet Forwarding in Mesh Network

    CERN Document Server

    Kanrar, Soumen

    2012-01-01

    Wireless Mesh Network (WMN) is a multi hop low cost, with easy maintenance robust network providing reliable service coverage. WMNs consist of mesh routers and mesh clients. In this architecture, while static mesh routers form the wireless backbone, mesh clients access the network through mesh routers as well as directly meshing with each other. Different from traditional wireless networks, WMN is dynamically self-organized and self-configured. In other words, the nodes in the mesh network automatically establish and maintain network connectivity. Over the years researchers have worked, to reduce the redundancy in broadcasting packet in the mesh network in the wireless domain for providing reliable service coverage, the source node deserves to broadcast or flood the control packets. The redundant control packet consumes the bandwidth of the wireless medium and significantly reduces the average throughput and consequently reduces the overall system performance. In this paper I study the optimization problem in...

  5. On Linear Spaces of Polyhedral Meshes.

    Science.gov (United States)

    Poranne, Roi; Chen, Renjie; Gotsman, Craig

    2015-05-01

    Polyhedral meshes (PM)-meshes having planar faces-have enjoyed a rise in popularity in recent years due to their importance in architectural and industrial design. However, they are also notoriously difficult to generate and manipulate. Previous methods start with a smooth surface and then apply elaborate meshing schemes to create polyhedral meshes approximating the surface. In this paper, we describe a reverse approach: given the topology of a mesh, we explore the space of possible planar meshes having that topology. Our approach is based on a complete characterization of the maximal linear spaces of polyhedral meshes contained in the curved manifold of polyhedral meshes with a given topology. We show that these linear spaces can be described as nullspaces of differential operators, much like harmonic functions are nullspaces of the Laplacian operator. An analysis of this operator provides tools for global and local design of a polyhedral mesh, which fully expose the geometric possibilities and limitations of the given topology.

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

    Directory of Open Access Journals (Sweden)

    Hemendra N Shah

    2012-01-01

    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

  7. Does expanded polytetrafluoroethylene mesh really shrink after laparoscopic ventral hernia repair?

    Science.gov (United States)

    Carter, P R; LeBlanc, K A; Hausmann, M G; Whitaker, J M; Rhynes, V K; Kleinpeter, K P; Allain, B W

    2012-06-01

    The shrinkage of mesh has been cited as a possible explanation for hernia recurrence. Expanded polytetrafluoroethylene (ePTFE) is unique in that it can be visualized on computed tomography (CT). Some animal studies have shown a greater than 40% rate of contraction of ePTFE; however, very few human studies have been performed. A total of 815 laparoscopic incisional/ventral hernia (LIVH) repairs were performed by a single surgical group. DualMesh Plus (ePTFE) (WL Gore & Associates, Newark, DE) was placed in the majority of these patients using both transfascial sutures and tack fixation. Fifty-eight patients had postoperative CTs of the abdomen and pelvis with ePTFE and known transverse diameter of the implanted mesh. The prosthesis was measured on the CT using the AquariusNet software program (TeraRecon, San Mateo, CA), which outlines the mesh and calculates the total length. Data were collected regarding the original mesh size, known linear dimension of mesh, seroma formation, and time interval since mesh implantation in months. The mean shrinkage rate was 6.7%. The duration of implantation ranged from 6 weeks to 78 months, with a median of 15 months. Seroma was seen in 8.6% (5) of patients. No relationship was identified between the percentage of shrinkage and the original mesh size (P = 0.78), duration of time implanted (P = 0.57), or seroma formation (P = 0.074). In 27.5% (16) of patients, no shrinkage of mesh was identified. Of the patients who did experience mesh shrinkage, the range of shrinkage was 2.6-25%. Our results are markedly different from animal studies and show that ePTFE has minimal shrinkage after LIVH repair. The use of transfascial sutures in addition to tack fixation may have an implication on the mesh contraction rates.

  8. Mesh Location in Open Ventral Hernia Repair: A Systematic Review and Network Meta-analysis.

    Science.gov (United States)

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

    2016-01-01

    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.

  9. Congenital Abdominal Wall Defects: Staged closure by Dual Mesh.

    Science.gov (United States)

    Risby, Kirsten; Jakobsen, Marianne Skytte; Qvist, Niels

    2016-01-01

    To evaluate the clinical utility of GORE® DUALMESH (GDM) in the staged closure of large congenital abdominal wall defects. Data of patients with congenital abdominal wall defects managed with GDM was analyzed for outcome regarding complete fascial closure; mesh related complications; and post-discharge gastrointestinal surgery. GDM was placed in 34 (gastroschisis=27, omphalocele=7) patients during the study period. Complete closure of the fascia was obtained in one patient with omphalocele and in 22 patients with gastroschisis. Mesh related surgical complications were seen in five (15%) children: four had detachment of the mesh and one patient developed abdominal compartment syndrome. Mesh related clinical infection was observed in five children. In hospital mortality occurred in four cases (2 gastroschisis and 2 omphalocele) and was not procedure-related. Of the 30 children discharged, 28 (82%) were still alive. At follow-up, three patients (10%) were operated for a minor ventral hernia and 4 children were operated (laparotomy and adhesionolysis) for adhesive intestinal obstruction. Staged closure with GDM is a safe alternative when primary fascial closure is difficult.

  10. [Ossiculoplasty with KURZ titanium prosthesis].

    Science.gov (United States)

    Nguyen, D-Q; Morel, N; Dumas, G; Troussier, J; Lavieille, J-P; Schmerber, S

    2005-09-01

    Report the functional and anatomic results of ossicular reconstruction by titanium prosthesis. Retrospective chart reviews were performed for 111 patients who had undergone titanium ossicular implants between November 1998 and 2002 (61 PORP, 50 TORP). The anatomical and audiometric data were analyzed on average at 3 and 20 months. At 20 months, the improvement of air-bone-gap mean was 12.7 dB with better results at low frequencies. The global success rate was 66% (PORP 77%, TORP 52%). It decreased significantly in the open techniques. Extrusion rate was low (2/111) and the labyrinthization rate was 3.6%. Twenty patients required a surgical revision (18%). In 9 patients, the prosthesis was too short. At long-term follow-up, the gains were stable in 60 patients, improved in 32 patients and worsened in 19 patients. The success rate is higher in the group of the PORP with the closed technique. The stability of the TORP in open technique still remains problematic. In all cases, the risk of extrusion requires a large cartilage graft recovering the plate of the prosthesis. The high rate of luxation (9/111 prosthesis too short) has led us to increase slightly the length of the prosthesis (+1.22 mm mean).

  11. The surgical treatment and clinical research for nickel-titanium memory alloy embracing surgery treating of multiple fractured ribs%镍钛记忆合金环抱器治疗多发性肋骨骨折的临床研究

    Institute of Scientific and Technical Information of China (English)

    李东; 窦学军

    2015-01-01

    目的:探讨镍钛记忆合金环抱器治疗多发性肋骨骨折的疗效。方法100例多发性肋骨骨折患者均采用镍钛记忆合金环抱器行手术治疗。结果患者均无感染,骨折不愈合及内固定松动、滑脱等并发症发生;术后5个月~12个月取出内固定,骨折部位无炎症反应,心肺功能恢复较好。结论镍钛记忆合金环抱器呈现出良好的组织相容性,手术操作简便、创伤小、并发症少,是一种较为理想的治疗多发性肋骨骨折的方法。%Objective This research was to explore the curative effect of nickel-titanium shape memory alloy fixator for treatment of multiple fractured ribs. Methods All of 100 patients was operated using Ti-Ni shape memory alloy embracing fixator for treatment of fracture of multiple ribs. Results All of patients were followed up lasting 5 to 12 months.The incision was healed in Phase I,and no complication occurred. Conclusions nickel-titanium shape memory alloy embracing fixator has the advantage of histocompatibility. The surgical trauma is small ,easy operation and fewer complications. Therefore,the above described surgery is an ideal method of treating of multiple fractured ribs. It is worth to spread in clinic.

  12. Inching toward 'push-button' meshing

    National Research Council Canada - National Science Library

    James Masters

    2015-01-01

      While "push-button" meshing remains an elusive goal, advances in 2015 have brought the technology to the point where meshes can be constructed with relative ease when appropriate surfaces are available...

  13. Corrosion wear fracture of new {beta} biomedical titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Niinomi, M.; Fukunaga, K.-I. [Toyohashi Univ. of Technol. (Japan). Dept. of Production Syst. Eng.; Kuroda, D.; Morinaga, M.; Kato, Y.; Yashiro, T.; Suzuki, A.

    1999-05-15

    Metallic materials such as stainless steel, Co-Cr alloy, pure titanium and titanium alloys have been used for surgical implant materials. The {alpha} + {beta} type titanium alloy such as Ti-6Al-4V ELI has been most widely used as an implant material for artificial hip joint and dental implant because of its high strength and excellent corrosion resistance. Toxicity of alloying elements in conventional biomedical titanium alloys like Al and V, and the high modulus of elasticity of these alloy as compared to that of bone have been, however, pointed out [1,2]. New {beta} type titanium alloys composed of non-toxic elements like Nb, Ta, Zr, Mo and Sn with lower moduli of elasticity, greater strength and greater corrosion resistance were, therefore, designed in this study. The friction wear properties of titanium alloys are, however, low as compared to those of other conventional metallic implant materials such as stainless steels and Co-Cr alloy. Tensile tests and friction wear tests in Ringer`s solution were conducted in order to investigate the mechanical properties of designed alloys. The friction wear characteristics of designed alloys and typical conventional biomedical titanium alloys were evaluated using a pin-on-disk type friction wear testing system and measuring the weight loss and width of groove of the specimen. (orig.) 8 refs.

  14. Volumetric Changes in Edentulous Alveolar Ridge Sites Utilizing Guided Bone Regeneration and a Custom Titanium Ridge Augmentation Matrix (CTRAM)

    Science.gov (United States)

    2016-06-01

    Milling CBCT Cone Beam Computed Tomography CT Computed Tomography CTRAM Custom Titanium Ridge Augmentation Matrix DMLS Direct Metal Laser Sintering ...could be used by Direct Metal Laser Sintering (DMLS) to create custom titanium mesh to reconstruct a deficient maxillary alveolar anterior ridge. A pre...Sinus Augmentations. Int J Periodont Rest Dent 2005; 25:231-237. Ciocca L, Fantini M, De Crescenzio F, Corinaldesi G, Scotti R. Direct Metal

  15. Particle Collection Efficiency for Nylon Mesh Screens

    OpenAIRE

    Cena, Lorenzo G.; Ku, Bon-Ki; Peters, Thomas M.

    2011-01-01

    Mesh screens composed of nylon fibers leave minimal residual ash and produce no significant spectral interference when ashed for spectrometric examination. These characteristics make nylon mesh screens attractive as a collection substrate for nanoparticles. A theoretical single-fiber efficiency expression developed for wire-mesh screens was evaluated for estimating the collection efficiency of submicrometer particles for nylon mesh screens. Pressure drop across the screens, the effect of part...

  16. 6th International Meshing Roundtable '97

    Energy Technology Data Exchange (ETDEWEB)

    White, D.

    1997-09-01

    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.

  17. 50 CFR 300.110 - Mesh size.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Mesh size. 300.110 Section 300.110... Antarctic Marine Living Resources § 300.110 Mesh size. (a) The use of pelagic and bottom trawls having the mesh size in any part of a trawl less than indicated is prohibited for any directed fishing for the...

  18. Markov Random Fields on Triangle Meshes

    DEFF Research Database (Denmark)

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

    2010-01-01

    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...... is a piecewise smooth mesh with explicit labelling of edges belonging to the sharp features....

  19. Mesh network achieve its fuction on Linux

    OpenAIRE

    Pei Ping; PETRENKO Y.N.

    2015-01-01

    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.

  20. The mesh network protocol evaluation and development

    OpenAIRE

    Pei Ping; PETRENKO Y.N.

    2015-01-01

    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.

  1. Functional results after repair of large hiatal hernia by use of a biologic mesh

    Directory of Open Access Journals (Sweden)

    Filimon eAntonakis

    2016-03-01

    Full Text Available Background: The aim of this observational study is to analyze the results of patients with large hiatal hernia and upside-down stomach after surgical closure with a biologic mesh (Permacol®, Covidien, Neustadt an der Donau, Germany. Biologic mesh is used to prevent long-term detrimental effects of artificial meshes and to reduce recurrence rates. Methods: A total of 13 patients with a large hiatal hernia and endothoracic stomach, who underwent surgery between 2010 and 2014, were included. Interviews and upper endoscopy were conducted to determine recurrence, lifestyle restrictions and current complaints. Results: After a mean follow-up of 26+18 months (range 3-58 months 10 patients (three men, mean age 73+13, range 26-81 years were evaluated. A small recurrent axial hernia was found in one patient postoperatively. Dysphagia was the most common complaint (four cases, while in one case the problem was solved after endoscopic dilatation. In three cases bloat and postprandial pain were documented. In one case explantation of the mesh was necessary due to mesh migration and painful adhesions. In one further case with gastroparesis pyloroplasty was performed without success.Conclusion: Recurrence was rare after hernia repair with the biologic mesh Permacol®. Dysphagia, gas bloat and intraabdominal pain were frequent complaints. Despite the small number of patients it can be concluded that a biologic mesh may be an alternative to synthetic meshes to reduce recurrences. Long-term results should be studied in the future in order to assess the potential of biologic meshes to preserve esophageal function as well. This is important since artificial meshes are known to erode the esophagus after 5–10 years.

  2. 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)

    2016-09-19

    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

  3. Prevention of parastomal hernia with a preperitoneal polypropelene mesh.

    Science.gov (United States)

    Valdés-Hernández, Javier; Díaz Milanés, Juan Antonio; Capitán Morales, Luis Cristóbal; Del Río la Fuente, Francisco Javier; Torres Arcos, Cristina; Cañete Gómez, Jesús; Oliva Mompeán, Fernando; Padillo Ruiz, Javier

    2015-01-01

    To show our results with the use of a polypropylene mesh at the stoma site, as prophylaxis of parastomal hernias in patients with rectal cancer when a terminal colostomy is performed. From January 2010 until March 2014, 45 consecutive patients with rectal cancer, underwent surgical treatment with the need of a terminal colostomy. A prophylactic mesh was placed in a sublay position at the stoma site in all cases. We analyze Demographics, technical issues and effectiveness of the procedure, as well as subsequent complications. A prophylactic mesh was placed in 45 patients, 35 male and 10 females, mean age of 66.2 (47-88) and Body Mass Index 29.19 (20.4-40.6). A total of 7 middle rectal carcinoma, 36 low rectal carcinoma, one rectal melanoma and one squamous cell anal carcinoma were electively treated with identical protocol. Abdominoperineal resection was performed in 38 patients, and low anterior resection with terminal colostomy in 7. An open approach was elected in 39 patients and laparoscopy in 6, with 2 conversions to open surgery. Medium follow up was 22 months (2.1-53). Overall, 3 parastomal hernias (6.66%) were found, one of which was a radiological finding with no clinical significance. No complications related to the mesh or the colostomy were found. The use of a prophylactic polypropylene mesh placed in a sublay position at the stoma site is a safe and feasible technique. It lowers the incidence of parastomal hernias with no increased morbidity. Copyright © 2014 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

  4. Correlation between shrinkage and infection of implanted synthetic meshes using an animal model of mesh infection.

    OpenAIRE

    Mamy, Laurent; Letouzey, Vincent; Lavigne, Jean-Philippe; Garric, Xavier; Gondry, Jean; Mares, Pierre; De Tayrac, Renaud

    2010-01-01

    International audience; INTRODUCTION AND HYPOTHESIS: The aim of this study was to evaluate a link between mesh infection and shrinkage. METHODS: Twenty-eight Wistar rats were implanted with synthetic meshes that were either non-absorbable (polypropylene (PP), n = 14) or absorbable (poly (D: ,L: -lactic acid) (PLA94), n = 14). A validated animal incisionnal abdominal hernia model of mesh infection was used. Fourteen meshes (n = 7 PLA94 and n = 7 PP meshes) were infected intraoperatively with 1...

  5. Confined helium on Lagrange meshes

    CERN Document Server

    Baye, Daniel

    2015-01-01

    The Lagrange-mesh method has the simplicity of a calculation on a mesh and can have the accuracy of a variational method. It is applied to the study of a confined helium atom. Two types of confinement are considered. Soft confinements by potentials are studied in perimetric coordinates. Hard confinement in impenetrable spherical cavities is studied in a system of rescaled perimetric coordinates varying in [0,1] intervals. Energies and mean values of the distances between electrons and between an electron and the helium nucleus are calculated. A high accuracy of 11 to 15 significant figures is obtained with small computing times. Pressures acting on the confined atom are also computed. For sphere radii smaller than 1, their relative accuracies are better than $10^{-10}$. For larger radii up to 10, they progressively decrease to $10^{-3}$, still improving the best literature results.

  6. 21st International Meshing Roundtable

    CERN Document Server

    Weill, Jean-Christophe

    2013-01-01

    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.

  7. The moving mesh code Shadowfax

    CERN Document Server

    Vandenbroucke, Bert

    2016-01-01

    We introduce the moving mesh code Shadowfax, which can be used to evolve a mixture of gas, subject to the laws of hydrodynamics and gravity, and any collisionless fluid only subject to gravity, such as cold dark matter or stars. The code is written in C++ and its source code is made available to the scientific community under the GNU Affero General Public License. We outline the algorithm and the design of our implementation, and demonstrate its validity through the results of a set of basic test problems, which are also part of the public version. We also compare Shadowfax with a number of other publicly available codes using different hydrodynamical integration schemes, illustrating the advantages and disadvantages of the moving mesh technique.

  8. The moving mesh code SHADOWFAX

    Science.gov (United States)

    Vandenbroucke, B.; De Rijcke, S.

    2016-07-01

    We introduce the moving mesh code SHADOWFAX, which can be used to evolve a mixture of gas, subject to the laws of hydrodynamics and gravity, and any collisionless fluid only subject to gravity, such as cold dark matter or stars. The code is written in C++ and its source code is made available to the scientific community under the GNU Affero General Public Licence. We outline the algorithm and the design of our implementation, and demonstrate its validity through the results of a set of basic test problems, which are also part of the public version. We also compare SHADOWFAX with a number of other publicly available codes using different hydrodynamical integration schemes, illustrating the advantages and disadvantages of the moving mesh technique.

  9. On the flexibility of Kokotsakis meshes

    OpenAIRE

    Karpenkov, Oleg

    2008-01-01

    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...

  10. Hiatal hernia repair with biologic mesh reinforcement reduces recurrence rate in small hiatal hernias.

    Science.gov (United States)

    Schmidt, E; Shaligram, A; Reynoso, J F; Kothari, V; Oleynikov, D

    2014-01-01

    The utility of mesh reinforcement for small hiatal hernia found especially during antireflux surgery is unknown. Initial reports for the use of biological mesh for crural reinforcement during repair for defects greater than 5 cm have been shown to decrease recurrence rates. This study compares patients with small hiatal hernias who underwent onlay biologic mesh buttress repair versus those with suture cruroplasty alone. This is a single-institution retrospective review of all patients undergoing repair of hiatal hernia measuring 1-5 cm between 2002 and 2009. The patients were evaluated based on surgical repair: one group undergoing crural reinforcement with onlay biologic mesh and other group with suture cruroplasty only. Seventy patients with hiatal hernia measuring 1-5 cm were identified. Thirty-eight patients had hernia repair with biologic mesh, and 32 patients had repair with suture cruroplasty only. Recurrence rate at 1 year was 16% (5/32) in patients who had suture cruroplasty only and 0% (0/38) in the group with crural reinforcement with absorbable mesh (statistically significant, P = 0.017). Suture cruroplasty alone appears to be inadequate for hiatal hernias measuring 1-5 cm with significant recurrence rate and failure of antireflux surgery. Crural reinforcement with absorbable mesh may reduce hiatal hernia recurrence rate in small hiatal hernias. © 2013 Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.

  11. An innovative approach to treating vaginal mesh exposure after abdominal sacral colpopexy: endoscopic resection of mesh and platelet-rich plasma; initial experience in three women.

    Science.gov (United States)

    Castellani, Daniele; Valloni, Alessandra; Piccirilli, Angela; Paradiso Galatioto, Giuseppe; Vicentini, Carlo

    2017-02-01

    Polypropylene mesh exposure is uncommon after abdominal sacral colpopexy (ASC), but in case of symptomatic vaginal mesh exposure, surgery is needed. When treating it, care must be taken to completely remove the exposed mesh (EM), saving as much vaginal tissue as possible to avoid a subsequent shortened and narrowed vagina. In this video, we present a minimally invasive technique for treating EM after ASC using endoscopic mesh resection and autologous platelet-rich plasma (PRP) technology. Three women were referred to our outpatient clinic for vaginal vault mesh exposure after laparoscopic ASC with concomitant hysterectomy. All women underwent endoscopic bipolar PlasmaKinetic resection (BPR) of EM, and PRP gel was delivered in the surgical site to cover the gap left by the resection. Mean operative time was 39.6 min. Surgery was uneventful in all cases. All women recovered sexual function, and nobody experienced relapsed pelvic organ prolapse at 1-year follow-up. Our preliminary results show that BPR and PRP are safe, effective, and feasible for treating vaginal mesh exposure with conservation of anatomy and sexual function.

  12. Application of single-incision transvaginal mesh in a woman undergoing peritoneal dialysis and suffering from refractory advanced stage pelvic organ prolapse

    Directory of Open Access Journals (Sweden)

    Yi-Hung Sun

    2017-05-01

    Conclusion: Patients with POP at an advanced stage during peritoneal dialysis who failed to be treated conservatively may require a surgical intervention. Uterus-sparing transvaginal mesh was a feasible minimal invasive option.

  13. Machining of titanium alloys

    CERN Document Server

    2014-01-01

    This book presents a collection of examples illustrating the resent research advances in the machining of titanium alloys. These materials have excellent strength and fracture toughness as well as low density and good corrosion resistance; however, machinability is still poor due to their low thermal conductivity and high chemical reactivity with cutting tool materials. This book presents solutions to enhance machinability in titanium-based alloys and serves as a useful reference to professionals and researchers in aerospace, automotive and biomedical fields.

  14. Image meshing via hierarchical optimization

    Institute of Scientific and Technical Information of China (English)

    Hao XIE; Ruo-feng TONG‡

    2016-01-01

    Vector graphic, as a kind of geometric representation of raster images, has many advantages, e.g., defi nition independence and editing facility. A popular way to convert raster images into vector graphics is image meshing, the aim of which is to fi nd a mesh to represent an image as faithfully as possible. For traditional meshing algorithms, the crux of the problem resides mainly in the high non-linearity and non-smoothness of the objective, which makes it difficult to fi nd a desirable optimal solution. To ameliorate this situation, we present a hierarchical optimization algorithm solving the problem from coarser levels to fi ner ones, providing initialization for each level with its coarser ascent. To further simplify the problem, the original non-convex problem is converted to a linear least squares one, and thus becomes convex, which makes the problem much easier to solve. A dictionary learning framework is used to combine geometry and topology elegantly. Then an alternating scheme is employed to solve both parts. Experiments show that our algorithm runs fast and achieves better results than existing ones for most images.

  15. Image meshing via hierarchical optimization*

    Institute of Scientific and Technical Information of China (English)

    Hao XIE; Ruo-feng TONGS

    2016-01-01

    Vector graphic, as a kind of geometric representation of raster images, has many advantages, e.g., definition independence and editing facility. A popular way to convert raster images into vector graphics is image meshing, the aim of which is to find a mesh to represent an image as faithfully as possible. For traditional meshing algorithms, the crux of the problem resides mainly in the high non-linearity and non-smoothness of the objective, which makes it difficult to find a desirable optimal solution. To ameliorate this situation, we present a hierarchical optimization algorithm solving the problem from coarser levels to finer ones, providing initialization for each level with its coarser ascent. To further simplify the problem, the original non-convex problem is converted to a linear least squares one, and thus becomes convex, which makes the problem much easier to solve. A dictionary learning framework is used to combine geometry and topology elegantly. Then an alternating scheme is employed to solve both parts. Experiments show that our algorithm runs fast and achieves better results than existing ones for most images.

  16. Grating droplets with a mesh

    Science.gov (United States)

    Soto, Dan; Le Helloco, Antoine; Clanet, Cristophe; Quere, David; Varanasi, Kripa

    2016-11-01

    A drop thrown against a mesh can pass through its holes if impacting with enough inertia. As a result, although part of the droplet may remain on one side of the sieve, the rest will end up grated through the other side. This inexpensive method to break up millimetric droplets into micrometric ones may be of particular interest in a wide variety of applications: enhancing evaporation of droplets launched from the top of an evaporative cooling tower or preventing drift of pesticides sprayed above crops by increasing their initial size and atomizing them at the very last moment with a mesh. In order to understand how much liquid will be grated we propose in this presentation to start first by studying a simpler situation: a drop impacting a plate pierced with a single off centered hole. The study of the role of natural parameters such as the radius drop and speed or the hole position, size and thickness allows us to discuss then the more general situation of a plate pierced with multiple holes: the mesh.

  17. Titanium allergy: A literature review

    Directory of Open Access Journals (Sweden)

    Manish Goutam

    2014-01-01

    Full Text Available Titanium has gained immense popularity and has successfully established itself as the material of choice for dental implants. In both medical and dental fields, titanium and its alloys have demonstrated success as biomedical devices. Owing to its high resistance to corrosion in a physiological environment and the excellent biocompatibility that gives it a passive, stable oxide film, titanium is considered the material of choice for intraosseous use. There are certain studies which show titanium as an allergen but the resources to diagnose titanium sensivity are very limited. Attention is needed towards the development of new and precise method for early diagnosis of titanium allergy and also to find out the alternative biomaterial which can be used in place of titanium. A review of available articles from the Medline and PubMed database was done to find literature available regarding titanium allergy, its diagnosis and new alternative material for titanium.

  18. Adaptive mesh generation for image registration and segmentation

    DEFF Research Database (Denmark)

    Fogtmann, Mads; Larsen, Rasmus

    2013-01-01

    This paper deals with the problem of generating quality tetrahedral meshes for image registration. From an initial coarse mesh the approach matches the mesh to the image volume by combining red-green subdivision and mesh evolution through mesh-to-image matching regularized with a mesh quality...

  19. Dynamic mesh for TCAD modeling with ECORCE

    Science.gov (United States)

    Michez, A.; Boch, J.; Touboul, A.; Saigné, F.

    2016-08-01

    Mesh generation for TCAD modeling is challenging. Because densities of carriers can change by several orders of magnitude in thin areas, a significant change of the solution can be observed for two very similar meshes. The mesh must be defined at best to minimize this change. To address this issue, a criterion based on polynomial interpolation on adjacent nodes is proposed that adjusts accurately the mesh to the gradients of Degrees of Freedom. Furthermore, a dynamic mesh that follows changes of DF in DC and transient mode is a powerful tool for TCAD users. But, in transient modeling, adding nodes to a mesh induces oscillations in the solution that appears as spikes at the current collected at the contacts. This paper proposes two schemes that solve this problem. Examples show that using these techniques, the dynamic mesh generator of the TCAD tool ECORCE handle semiconductors devices in DC and transient mode.

  20. SHARP/PRONGHORN Interoperability: Mesh Generation

    Energy Technology Data Exchange (ETDEWEB)

    Avery Bingham; Javier Ortensi

    2012-09-01

    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.

  1. Cluster parallel rendering based on encoded mesh

    Institute of Scientific and Technical Information of China (English)

    QIN Ai-hong; XIONG Hua; PENG Hao-yu; LIU Zhen; SHI Jiao-ying

    2006-01-01

    Use of compressed mesh in parallel rendering architecture is still an unexplored area, the main challenge of which is to partition and sort the encoded mesh in compression-domain. This paper presents a mesh compression scheme PRMC (Parallel Rendering based Mesh Compression) supplying encoded meshes that can be partitioned and sorted in parallel rendering system even in encoded-domain. First, we segment the mesh into submeshes and clip the submeshes' boundary into Runs, and then piecewise compress the submeshes and Runs respectively. With the help of several auxiliary index tables, compressed submeshes and Runs can serve as rendering primitives in parallel rendering system. Based on PRMC, we design and implement a parallel rendering architecture. Compared with uncompressed representation, experimental results showed that PRMC meshes applied in cluster parallel rendering system can dramatically reduce the communication requirement.

  2. SURGICAL TREATMENT OF UPPER AND MIDDLE FACIAL ZONE TRAUMAS IN PROGRESS OF CONCOMITANT TRAUMATIC CRANIOFACIAL INJURIES.

    Science.gov (United States)

    Lagvilava, G; Gvenetadze, Z; Toradze, G; Devidze, I; Gvenetadze, G

    2015-09-01

    In 2012-2015, 207 patients with concomitant craniofacial injuries, who underwent surgical treatment, were observed; among them 176 were men and 31- women. Age of the patients ranged from 16 to 60 years. According to localization and severity of trauma and a priority of surgical intervention, the patients conventionally were divided into 3 groups by the authors: I group (65 patients) - craniofacial injuries; the skull as well as upper and middle areas of face (subcranial and frontobasal fractures) were affected (fractured). II group (80 patients) - severe traumatic injuries of upper and especially middle zones of the face, accompanied with closed craniocerebral trauma, no need in neurosurgery. III group (62 patients) -on the background of serious head traumas, the injuries of face bones were less severe (injury of one or two anatomic areas with displacement of fractured fragments but without bone tissue defects) According to the obtained results a priority was always given to the neurosurgery (vital testimony).The reconstructive surgeries on face skeleton was conducted in combination involving neurosurgeons (I group patients). Reconstructive surgeries of facial bones were conducted in the patients of II group, immediately or at primary deferred period of time but in the patients of III group the surgical procedures for removal of early secondary or traumatic residual fractures have been performed. Reposition of the fractured facial bone fragments was performed in an open way and fixation was carried out by titanium plates and mesh cage (at bone tissue defect). For prevention and elimination of post-traumatic inflammatory processes, the final stage of surgical intervention was: sanation of nasal accessory sinuses and catheterization (5-7 days) of external carotid arteries for administration of antibiotics and other medical preparations. Early and differentiated approach to face injuries, worsening in the course of craniocephalic trauma was not revealed in any patient

  3. Comparative analysis of autodermal graft and polypropylene mesh use in large incisional hernia defects reconstruction

    Directory of Open Access Journals (Sweden)

    Stojiljković Danilo

    2013-01-01

    Full Text Available Background. Large defects of the abdominal wall caused by incisional hernia still represent a challenging problem in plastic, reconstructive, and abdominal surgery. For their successful tension-free repair a proper selection of reconstructive material is essential. In the last decades, the use of synthetic meshes was dominant while biological autodermal grafts were rarely used. The aim of the study was to comparatively analyse efficacy and safety of autodermal graft and polypropylene mesh in surgical treatment of large abdominal wall defects. Methods. This prospective comparative clinical study enroled 40 patients surgically treated for large incisional hernia repair in a 10-year period. The patients were divided into two equal groups consisting of 20 subjects and treated either by biological autodermal graft or by synthetic polypropylene mesh. The surgical techniques of reconstruction, duration of surgery, the occurrence of early, minor, and major (severe and delyed complications and hospital stay were analyzed. The average follow-up took 2 years. Results. Statistically significant differences in demographic characteristics of patients and in size of defects were not found. The surgical technique of reconstruction with an autodermal graft was more complicated. The duration of surgery in patients treated with autodermal grafts was significantly longer. There was no statistically significant difference regarding occurrence of early, minor postoperative complications and hospital stay in our study. Two severe complications were registered in the synthetic mesh group: intestinal obstruction and enterocutaneous fistula. The recurrence rate was 10% in the autodermal graft group and 15% in the group with a synthetic mesh. Conclusion. Tension-free repair of large incisional hernia with autodermal grafts was unjustly neglected despite the fact that it is safe and effective. It can be applied in all cases where synthetic mesh are not indicated (presence

  4. INCISIONAL HERNIOPLASTY WITH MERSILEN MESH AND FULL AHDOMINOPLASTY

    Directory of Open Access Journals (Sweden)

    M HASHEMI

    2003-09-01

    Full Text Available ncisional Hernia is a complication after any abdominal incision. During 10 years we have done 25 incision Hernia repair by mersilen mesh and full abdominoplasty. The Hospital stay was 3-5 days, and has followed the patients for 3 months to 10 years. There was no recurrence, infection, fat emboli or other complication during this period. All the patients were satistitied frame their abdominal shape and surgical scar we advice this technique as an effective and simple method for repairing of incision hernia especially for recurrence.

  5. Lower Reoperation Rate for Recurrence after Mesh versus Sutured Elective Repair in Small Umbilical and Epigastric Hernias. A Nationwide Register Study

    DEFF Research Database (Denmark)

    Christoffersen, Mette Willaume; Helgstrand, F; Rosenberg, J;

    2013-01-01

    Repair for a small (≤2 cm) umbilical and epigastric hernia is a minor surgical procedure. The most common surgical repair techniques are a sutured repair or a repair with mesh reinforcement. However, the optimal repair technique with regard to risk of reoperation for recurrence is not well...... documented. The aim of the present study was in a nationwide setup to investigate the reoperation rate for recurrence after small open umbilical and epigastric hernia repairs using either sutured or mesh repair....

  6. The Use of Mesh Plates for Difficult Fractures of the Patella.

    Science.gov (United States)

    Volgas, David; Dreger, Tina K

    2017-03-01

    Patella fractures present some of the more complicated fracture patterns in orthopaedic trauma care. This is partially due to the small size of the fragments but also the articular nature of each fragment. Fixation methods such as cerclage wiring, excision of smaller fragments, and screw fixation of larger fragments all have their own challenges. Our study examined our Level I trauma center's experience with variable angle locked 2.7 mm titanium plates for treatment of comminuted patella fractures or treatment of patellar nonunion. After Institutional Review Board approval, we used billing records to identify 105 patients who had undergone operative management of a displaced patella fracture between January 2011 and December 2015. We reviewed the radiographs of these patients to identify which patients underwent treatment with a mesh plate. We found 16 patients (6 males and 10 females) who had undergone fixation with a mesh plate; mean age was 47 years. Nine patients underwent primary open reduction internal fixation (ORIF) and seven underwent mesh plate fixation for failed ORIF of a patella fracture. The mean visual analog pain score was 2.75 (range, 0-9). The mean range of motion was 1 degree of extension (range, 0-10 degrees) to 110 degrees of flexion (range, 45-135 degrees). All fractures healed. Five patients required hardware removal for pain. This review illustrates the effectiveness of the locking mesh plate in two challenging clinical scenarios: that of patellar nonunion and comminuted fractures that preclude standard fixation methods. Although multiple options exist for patellar fracture fixation, the titanium mesh locking plate can be an effective option for retaining the patella in the setting of comminution. Further comparative studies should be undertaken to determine which method of treatment may be superior in the treatment of these fractures. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  7. Deep SSI after mesh-mediated groin hernia repair: management and outcome in an Emergency Surgery Department.

    Science.gov (United States)

    Salamone, G; Licari, L; Augello, G; Campanella, S; Falco, N; Tutino, R; Cocorullo, G; Gullo, R; Raspanti, C; De Marco, P; Porrello, C; Profita, G; Gulotta, G

    2017-01-01

    Mesh-mediated groin hernia repair is considered the goldstandard procedure. It has low recurrence rate. Rarely a deep Surgical Site Infection (SSI) is seen when a synthetic prosthesis is used. We describe a rare case of bilateral deep SSI after mesh-mediated groin hernia repair. Diagnosis was performed through the physical examination and radiological exams. Microbiological samples identified a methicillin-resistant Staphylococcus aureus responsible of the infection. Target therapy was performed and re-operation performed in order to remove the infected prosthesis and to apply a biological one to create the fibrous scaffold. During follow-up time, right side recurrence was observed. Tru-cut biopsy of fascia was obtained in order to identify the responsible of the recurrence. Combination of antibiotic therapy and surgical reoperation seems to be the correct way to approach the deep SSI after mesh-mediated groin hernia repair. The use of biological mesh after synthetic removal seems to improve the final outcome.

  8. Synthetic Versus Biological Mesh-Related Erosion After Laparoscopic Ventral Mesh Rectopexy: A Systematic Review.

    Science.gov (United States)

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

    2017-04-01

    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.

  9. Cost-Effectiveness of a Biodegradable Compared to a Titanium Fixation System in Maxillofacial Surgery : A Multicenter Randomized Controlled Trial

    NARCIS (Netherlands)

    van Bakelen, N. B.; Vermeulen, K. M.; Buijs, G. J.; Jansma, J.; de Visscher, J. G. A. M.; Hoppenreijs, Th. J. M.; Bergsma, J. E.; Stegenga, B.; Bos, R. R. M.

    2015-01-01

    Background Biodegradable fixation systems could reduce/delete the problems associated with titanium plate removal. This means less surgical discomfort, and a reduction in costs. Aim The aim of the present study was to compare the cost-effectiveness between a biodegradable and a titanium system in

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

    Directory of Open Access Journals (Sweden)

    Jennings Jason

    2010-01-01

    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.

  11. Synthetic Mesh Augmentation of Acute and Subacute Quadriceps Tendon Repair.

    Science.gov (United States)

    Morrey, Matthew C; Barlow, Jonathan D; Abdel, Matthew P; Hanssen, Arlen D

    2016-01-01

    Quadriceps tendon rupture is an uncommon injury. To date, surgical results have been less than favorable. A novel repair technique that uses Marlex mesh (C R Bard, Murray Hill, New Jersey) has been developed. Use of this repair may allow earlier range of motion and functional restoration of extension. The authors sought to evaluate the technical feasibility, durability, and postoperative function of this repair. This study retrospectively analyzed 8 knees (7 patients) operated on with this technique from 1990 to 2011. Mean follow-up was 9 years. Average age at the time of injury was 69 years. Mean operative time was 130 minutes. No perioperative complications occurred, no patients had clinical evidence of failure, and no patients required subsequent reoperation. Mean flexion at final follow-up was 100°. Of the 8 knees, 7 knees had no extensor lag at final follow-up. Marlex mesh augmentation for quadriceps tendon ruptures has promising clinical results, despite significant comorbidities. The results showed that the technique was feasible, with low cost and reasonable operative time. The clinical results were durable, with no intraoperative complications, no re-ruptures, rare extension lag, and good range of motion. Therefore, synthetic mesh augmentation is a feasible option in acute quadriceps tendon ruptures.

  12. Fijación quirúrgica de fracturas costales con placas de titanio: reporte de dos casos Surgical repair of rib fractures using titanium plates: Report of two cases

    Directory of Open Access Journals (Sweden)

    Mauricio Fica D

    2012-12-01

    Full Text Available Las fracturas costales son lesiones frecuentes en los traumatismos torácicos contusos. Sin contar aquellas lesiones asociadas con la alta absorción de energía, las fracturas costales causan característicamente dolor intenso, complicaciones respiratorias y ausentismo laboral significativo. Una de las estrategias terapéuticas es la estabilización quirúrgica del foco de fractura, la cual tiene múltiples ventajas teóricas como la disminución del dolor y la restauración de la función de la pared costal. Existen múltiples formas de fijación costal, pero su indicación, técnica quirúrgica y resultados son muy disímiles. Presentamos dos casos de reparación de pared torácica con material de osteosíntesis especialmente diseñado para este efecto (Synthes® MatrixRIB, Solothurn, Suiza, y se discuten sus alcances en las indicaciones y resultados clínicos.Rib fractures are common lesions in blunt chest trauma. Disregarding the severity of other high energy associated lesions, chest wall trauma characteristically causes intense pain, respiratory complications and long-term disability. Pain relief and chest wall function restoration are obtained by surgical stabilization of rib fractures. In nowdays still there is a considerable variability in surgical techniques and devices, as well as in their results and clinical indications. We report two cases of chest wall trauma and rib fractures repaired with osteosynthesis (Synthes® system MatrixRIB. Solothurn, Switzerland and we discuss their new clinical indications and results.

  13. An effective quadrilateral mesh adaptation

    Institute of Scientific and Technical Information of China (English)

    KHATTRI Sanjay Kumar

    2006-01-01

    Accuracy of a simulation strongly depends on the grid quality. Here, quality means orthogonality at the boundaries and quasi-orthogonality within the critical regions, smoothness, bounded aspect ratios and solution adaptive behaviour. It is not recommended to refine the parts of the domain where the solution shows little variation. It is desired to concentrate grid points and cells in the part of the domain where the solution shows strong gradients or variations. We present a simple, effective and computationally efficient approach for quadrilateral mesh adaptation. Several numerical examples are presented for supporting our claim.

  14. Composite mesh and gluteal fasciocutaneous rotation flap for perineal hernia repair after abdominoperineal resection: a novel technique.

    Science.gov (United States)

    Papadakis, Marios; Hübner, Gunnar; Bednarek, Marzena; Arafkas, Mohamed

    2017-03-01

    Perineal hernia is an uncommon complication following abdominoperineal rectum resection. Several surgical procedures have been proposed for perineal hernia repair, including perineal, laparoscopic and abdominal approaches. Repair techniques can be classified into primary suture techniques, mesh placements and repairs with autogenous tissue. We report a 68-year-old man with a perineal hernia, who underwent a pelvic floor reconstruction with a transperineal composite mesh and a gluteal fasciocutaneous rotation flap. We conclude that a combined approach with transperineal mesh reconstruction and gluteal fasciocutaneous flap could be an alternative choice in perineal hernia repair after abdominoperineal resection.

  15. Advantages of implantation of acellular porcine-derived mesh in the treatment of human rectocele – Case report

    Directory of Open Access Journals (Sweden)

    Tomasz Kościński

    2016-09-01

    Full Text Available Introduction. A rectocele is a hernation of the rectum into the vaginal lumen developing as a consequence of weakness of the rectovaginal septum. It affects about 18% of women after childbearing age. Symptoms associated with a rectocele include constipation, vaginal fullness or heaviness, feeling of a bulging mass within vagina, incomplete stool evacuation and dyspareunia. Current methods of surgical treatment of a rectocele often require implantation of a mesh graft. In most of cases, synthetic and non-absorbable meshes are used. Although implantation of a synthetic and non-absorbable mesh is effective in the treatment of rectocele, a high rate of mesh erosion has been reported. Case report. This study presents a surgical technique and case report for the treatment of a rectocele in a 46-year-old women by implantation of a porcine-derived absorbable collagen mesh (Pelvicol® by transvaginal approach, with six year follow-up. A review of the literature concerning implantation of Pelvicol® for the treatment of rectocele was also undertaken. Conclusions. The clinical experience and review of the literature by the authors suggest that a porcine-derived acellular mesh is non-cytotoxic, pyrogenic or allergenic, and the application of a biomesh in the management of rectocele is effective and safe, and the risk of mesh erosion is very low.

  16. Bluetooth Low Energy Mesh Networks: A Survey.

    Science.gov (United States)

    Darroudi, Seyed Mahdi; Gomez, Carles

    2017-06-22

    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.

  17. Mesh networking optimized for robotic teleoperation

    Science.gov (United States)

    Hart, Abraham; Pezeshkian, Narek; Nguyen, Hoa

    2012-06-01

    Mesh networks for robot teleoperation pose different challenges than those associated with traditional mesh networks. Unmanned ground vehicles (UGVs) are mobile and operate in constantly changing and uncontrollable environments. Building a mesh network to work well under these harsh conditions presents a unique challenge. The Manually Deployed Communication Relay (MDCR) mesh networking system extends the range of and provides non-line-of-sight (NLOS) communications for tactical and explosive ordnance disposal (EOD) robots currently in theater. It supports multiple mesh nodes, robots acting as nodes, and works with all Internet Protocol (IP)-based robotic systems. Under MDCR, the performance of different routing protocols and route selection metrics were compared resulting in a modified version of the Babel mesh networking protocol. This paper discusses this and other topics encountered during development and testing of the MDCR system.

  18. MPDATA error estimator for mesh adaptivity

    Science.gov (United States)

    Szmelter, Joanna; Smolarkiewicz, Piotr K.

    2006-04-01

    In multidimensional positive definite advection transport algorithm (MPDATA) the leading error as well as the first- and second-order solutions are known explicitly by design. This property is employed to construct refinement indicators for mesh adaptivity. Recent progress with the edge-based formulation of MPDATA facilitates the use of the method in an unstructured-mesh environment. In particular, the edge-based data structure allows for flow solvers to operate on arbitrary hybrid meshes, thereby lending itself to implementations of various mesh adaptivity techniques. A novel unstructured-mesh nonoscillatory forward-in-time (NFT) solver for compressible Euler equations is used to illustrate the benefits of adaptive remeshing as well as mesh movement and enrichment for the efficacy of MPDATA-based flow solvers. Validation against benchmark test cases demonstrates robustness and accuracy of the approach.

  19. Bluetooth Low Energy Mesh Networks: A Survey

    Science.gov (United States)

    Darroudi, Seyed Mahdi; Gomez, Carles

    2017-01-01

    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. PMID:28640183

  20. Unstructured Polyhedral Mesh Thermal Radiation Diffusion

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-07-27

    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.

  1. Delaunay triangulation and computational fluid dynamics meshes

    Science.gov (United States)

    Posenau, Mary-Anne K.; Mount, David M.

    1992-01-01

    In aerospace computational fluid dynamics (CFD) calculations, the Delaunay triangulation of suitable quadrilateral meshes can lead to unsuitable triangulated meshes. Here, we present case studies which illustrate the limitations of using structured grid generation methods which produce points in a curvilinear coordinate system for subsequent triangulations for CFD applications. We discuss conditions under which meshes of quadrilateral elements may not produce a Delaunay triangulation suitable for CFD calculations, particularly with regard to high aspect ratio, skewed quadrilateral elements.

  2. Titanium metal: extraction to application

    Energy Technology Data Exchange (ETDEWEB)

    Gambogi, Joseph (USGS, Reston, VA); Gerdemann, Stephen J.

    2002-09-01

    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium. In this paper, we discuss all aspects of the titanium industry from ore deposits through extraction to present and future applications. The methods of both primary (mining of ore, extraction, and purification) and secondary (forming and machining) operations will be analyzed. The chemical and physical properties of titanium metal will be briefly examined. Present and future applications for titanium will be discussed. Finally, the economics of titanium metal production also are analyzed as well as the advantages and disadvantages of various alternative extraction methods.

  3. Surface modification of titanium and titanium alloys by ion implantation.

    Science.gov (United States)

    Rautray, Tapash R; Narayanan, R; Kwon, Tae-Yub; Kim, Kyo-Han

    2010-05-01

    Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, to improve the biological, chemical, and mechanical properties, surface modification is often performed. In view of this, the current review casts new light on surface modification of titanium and titanium alloys by ion beam implantation.

  4. Design of electrospinning mesh devices

    Science.gov (United States)

    Russo, Giuseppina; Peters, Gerrit W. M.; Solberg, Ramon H. M.; Vittoria, Vittoria

    2012-07-01

    This paper describes the features of new membranes that can act as local biomedical devices owing to their peculiar shape in the form of mesh structure. These materials are designed to provide significant effects to reduce local inflammations and improve the tissue regeneration. Lamellar Hydrotalcite loaded with Diclofenac Sodium (HTLc-DIK) was homogenously dispersed inside a polymeric matrix of Poly-caprolactone (PCL) to manufacture membranes by electrospinning technique. The experimental procedure and the criteria employed have shown to be extremely effective at increasing potentiality and related applications. The employed technique has proved to be very useful to manufacture polymeric fibers with diameters in the range of nano-micro scale. In this work a dedicated collector based on a proprietary technology of IME Technologies and Eindhoven University of Technology (TU/e) was used. It allowed to obtain devices with a macro shape of a 3D-mesh. Atomic Force Microscopy (AFM) highlights a very interesting texture of the electrospun fibers. They show a lamellar morphology that is only slightly modified by the inclusion of the interclay embedded in the devices to control the drug release phenomena.

  5. Conformal refinement of unstructured quadrilateral meshes

    Energy Technology Data Exchange (ETDEWEB)

    Garmella, Rao [Los Alamos National Laboratory

    2009-01-01

    We present a multilevel adaptive refinement technique for unstructured quadrilateral meshes in which the mesh is kept conformal at all times. This means that the refined mesh, like the original, is formed of only quadrilateral elements that intersect strictly along edges or at vertices, i.e., vertices of one quadrilateral element do not lie in an edge of another quadrilateral. Elements are refined using templates based on 1:3 refinement of edges. We demonstrate that by careful design of the refinement and coarsening strategy, we can maintain high quality elements in the refined mesh. We demonstrate the method on a number of examples with dynamically changing refinement regions.

  6. MOAB : a mesh-oriented database.

    Energy Technology Data Exchange (ETDEWEB)

    Tautges, Timothy James; Ernst, Corey; Stimpson, Clint; Meyers, Ray J.; Merkley, Karl

    2004-04-01

    A finite element mesh is used to decompose a continuous domain into a discretized representation. The finite element method solves PDEs on this mesh by modeling complex functions as a set of simple basis functions with coefficients at mesh vertices and prescribed continuity between elements. The mesh is one of the fundamental types of data linking the various tools in the FEA process (mesh generation, analysis, visualization, etc.). Thus, the representation of mesh data and operations on those data play a very important role in FEA-based simulations. MOAB is a component for representing and evaluating mesh data. MOAB can store structured and unstructured mesh, consisting of elements in the finite element 'zoo'. The functional interface to MOAB is simple yet powerful, allowing the representation of many types of metadata commonly found on the mesh. MOAB is optimized for efficiency in space and time, based on access to mesh in chunks rather than through individual entities, while also versatile enough to support individual entity access. The MOAB data model consists of a mesh interface instance, mesh entities (vertices and elements), sets, and tags. Entities are addressed through handles rather than pointers, to allow the underlying representation of an entity to change without changing the handle to that entity. Sets are arbitrary groupings of mesh entities and other sets. Sets also support parent/child relationships as a relation distinct from sets containing other sets. The directed-graph provided by set parent/child relationships is useful for modeling topological relations from a geometric model or other metadata. Tags are named data which can be assigned to the mesh as a whole, individual entities, or sets. Tags are a mechanism for attaching data to individual entities and sets are a mechanism for describing relations between entities; the combination of these two mechanisms is a powerful yet simple interface for representing metadata or application

  7. A novel technique of midline mesh repair for umbilical hernia associated with diastasis recti.

    Science.gov (United States)

    Matei, Ovidio-Angel; Runkel, Norbert

    2014-03-01

    Mesh repair has evolved as the gold standard for umbilical hernias. Surgical reconstruction of umbilical hernias in association with diastasis recti has not been discussed in the recent literature. We describe a novel surgical technique of midline mesh repair for this combined lesion. This is a retrospective review of 44 consecutive patients. Forty-four patients underwent surgery for umbilical hernia with diastasis recti between January 2010 and August 2012. All excess skin, subcutaneous tissue, and distracted midline (linea alba) were excised supraumbilically and paraumbilically according to preoperative marking. Surgical repair began with a midline running suture of the posterior rectal sheath. A light prolene mesh was placed retromuscularly into this sheath and anchored in all directions with a distance of about 5 cm from the midline using U-shaped stitches. The anterior rectal fascia was closed with a continuous suture. All information was obtained from the hospital records. The median operative time was 93.3 minutes (28 to 219 minutes). The median length of postoperative hospital stay was 5.9 days (3 to 12 days). There was no major complication. One minimal umbilical skin necrosis was observed. Analgesic medication was required in all patients. Opiods were added in 84.0% of patients on day 1, in 75.0% on day 3, and in 2.3% on day 7. Our novel technique of sublay mesh repair for combined umbilical hernia and diastasis recti is safe and effectively restores the abdominal midline.

  8. PROSPECTIVE STUDY ON DARNING AND LICHTENSTEIN MESH HERNIOPLASTY (LMH IN INGUINAL HERNIA REPAIR

    Directory of Open Access Journals (Sweden)

    Affin

    2016-01-01

    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.

  9. The “Pelvic Harness”: a skeletonized mesh implant for safe pelvic floor reconstruction

    Science.gov (United States)

    Natalia, Sumerova; Menahem, Neuman; Haim, Krissi; Dmitri, Pushkar

    2016-01-01

    ABSTRACT Objectives To evaluate the feasibility, safety and surgical results of skeletonized mesh implants to form a pelvic harness for pelvic floor reconstruction surgery. Study design Patients with advanced pelvic floor prolapse were enrolled to this study. Study model was a kit mesh, reduced to 75% of the original surface area by cutting out mesh material from the central mesh body. Patients were evaluated at the end of the 1st and 6th post-operative months and interviewed at the study conclusion. Results Ninety-five women with advanced pelvic floor prolapse had this implant. Mean follow-up duration was 9 months (6-12 months). The POP-Q point’s measurements showed marked and statistically significant improvements. Bladder over-activity symptoms, fecal incontinence, pelvic pain and constipation rates were all reduced as well. No adverse effects related to the dissection or mesh implantation were marked. The first and sixth post-operative month follow-up records as well as the study conclusion interview findings were satisfactory in terms of subjective and objective cure and adverse effects occurrence. Conclusion This study data proposes that skeletonizing meshes might be safely and successfully implanted for potentially improved pelvic floor reconstruction. PMID:27286114

  10. The “Pelvic Harness”: a skeletonized mesh implant for safe pelvic floor reconstruction

    Directory of Open Access Journals (Sweden)

    Sumerova Natalia

    2016-06-01

    Full Text Available ABSTRACT Objectives To evaluate the feasibility, safety and surgical results of skeletonized mesh implants to form a pelvic harness for pelvic floor reconstruction surgery. Study design Patients with advanced pelvic floor prolapse were enrolled to this study. Study model was a kit mesh, reduced to 75% of the original surface area by cutting out mesh material from the central mesh body. Patients were evaluated at the end of the 1st and 6th post-operative months and interviewed at the study conclusion. Results Ninety-five women with advanced pelvic floor prolapse had this implant. Mean follow-up duration was 9 months (6-12 months. The POP-Q point’s measurements showed marked and statistically significant improvements. Bladder over-activity symptoms, fecal incontinence, pelvic pain and constipation rates were all reduced as well. No adverse effects related to the dissection or mesh implantation were marked. The first and sixth post-operative month follow-up records as well as the study conclusion interview findings were satisfactory in terms of subjective and objective cure and adverse effects occurrence. Conclusion This study data proposes that skeletonizing meshes might be safely and successfully implanted for potentially improved pelvic floor reconstruction.

  11. Microstructure Analysis of Laser Remelting for Thermal Barrier Coatings on the Surface of Titanium Alloy

    Directory of Open Access Journals (Sweden)

    Lu Bin

    2016-01-01

    Full Text Available In this paper, the preparation and organization performance of thermal barrier coatings (TCBs on the surface of titanium were studied experimentally. Nanostructured 8 wt% yttria partially stabilized zirconia coatings were deposited by air plasma spraying. The microstructure of nanostructured and the conventional coating was studied after laser remelting. It has shown that formed a network of micro-cracks and pits after laser remelting on nanostructured coatings. With the decrease of the laser scanning speed, mesh distribution of micro cracks was gradually thinning on nanostructured coatings. Compared with conventional ceramic layers, the mesh cracks of nanostructured coating is dense and the crack width is small.

  12. Mesh Exposure and Associated Risk Factors in Women Undergoing Transvaginal Prolapse Repair with Mesh

    Directory of Open Access Journals (Sweden)

    Elizabeth A. Frankman

    2013-01-01

    Full Text Available Objective. To determine frequency, rate, and risk factors associated with mesh exposure in women undergoing transvaginal prolapse repair with polypropylene mesh. Methods. Retrospective chart review was performed for all women who underwent Prolift Pelvic Floor Repair System (Gynecare, Somerville, NJ between September 2005 and September 2008. Multivariable logistic regression was performed to identify risk factors for mesh exposure. Results. 201 women underwent Prolift. Mesh exposure occurred in 12% (24/201. Median time to mesh exposure was 62 days (range: 10–372. When mesh was placed in the anterior compartment, the frequency of mesh exposure was higher than that when mesh was placed in the posterior compartment (8.7% versus 2.9%, P=0.04. Independent risk factors for mesh exposure were diabetes (AOR = 7.7, 95% CI 1.6–37.6; P=0.01 and surgeon (AOR = 7.3, 95% CI 1.9–28.6; P=0.004. Conclusion. Women with diabetes have a 7-fold increased risk for mesh exposure after transvaginal prolapse repair using Prolift. The variable rate of mesh exposure amongst surgeons may be related to technique. The anterior vaginal wall may be at higher risk of mesh exposure as compared to the posterior vaginal wall.

  13. Tensile Behaviour of Welded Wire Mesh and Hexagonal Metal Mesh for Ferrocement Application

    Science.gov (United States)

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

    2017-08-01

    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.

  14. Polypropylene-based composite mesh versus standard polypropylene mesh in the reconstruction of complicated large abdominal wall hernias: a prospective randomized study.

    Science.gov (United States)

    Kassem, M I; El-Haddad, H M

    2016-10-01

    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.

  15. 眶颅骨纤维异常增殖症病灶手术切除与缺损区钛金属修复%Resection of orbito-cranial fibrous dysplasia lesion and reconstruction with titanium

    Institute of Scientific and Technical Information of China (English)

    许蓓; 马建荣; 易文殊; 谭佳; 向前; 许雪亮

    2012-01-01

    目的:研究眶颅骨纤维异常增殖症手术切除病灶的时机和方法,总结病灶切除后钛金属修复骨缺损的经验,对手术的疗效进行评估.方法:对21例出现视功能障碍或明显外观影响的患者进行术前常规冠状位、水平位、矢状位及三维CT扫描.对眶颅骨病变范围大的患者,将CT扫描图像数据输入计算机,经过处理后制作钛金属三维实体修复体;对于累及眶颅骨病变范围较小的患者,则用手工的方法在手术中制作近似于正常眼眶和颅骨部的修复体.全部病例均采用经颅手术切除病变骨组织,并用钛板和钛网修复缺损区.结果:21例患者中18例一次性切除干净,3例累及海绵窦区域者进行姑息性切除.13例伴有不同程度的视力下降,11例术后视力明显上升,视力恢复在3~5行.外观畸形的11例患者术后得到明显改善.结论:眶颅骨纤维异常增殖症患者只要影响到视功能或造成眶颅外观畸形,应该尽早进行手术切除.钛金属修复手术后遗留的骨缺损具有牢固、可塑性强、固定简易等优点.%Objective: To discuss the method and opportunity of operation for orbito-cranial fibrous dysplasia, and further to summarize our experience in repairing the bony defect with titanium after excision and assess the surgical outcomes.Methods: A retrospective study was performed in 21 patients with visual function damage and/ or orbital malformation, who treated surgically. All patients were underwent CT examinations (coronal, horizontal, sagittal and three-dimensional scans) before surgery. CT image data of patients with serious orbital skull lesions were analyzed by computer to produce the three-dimensional, solid titanium mesh prostheses used to repair the lesions; for smaller lesions solid titanium mesh prostheses were shaped artificially during surgery according to the normal orbit and the cranium. All the patients were treated surgically via craniofacial approach

  16. Onlay with Adhesive Use Compared with Sublay Mesh Placement in Ventral Hernia Repair: Was Chevrel Right? An Americas Hernia Society Quality Collaborative Analysis.

    Science.gov (United States)

    Haskins, Ivy N; Voeller, Guy R; Stoikes, Nathaniel F; Webb, David L; Chandler, Robert G; Phillips, Sharon; Poulose, Benjamin K; Rosen, Michael J

    2017-05-01

    The use of mesh during ventral hernia repair (VHR) is a well-accepted concept. However, the ideal location of mesh placement remains strongly debated. Although VHR with onlay mesh placement has historically been associated with a high rate of wound events, this surgical approach is technically less challenging than VHR with sublay mesh placement. The purpose of this study was to compare 30-day wound events after onlay mesh placement with adhesive fixation vs those after sublay mesh placement using the Americas Hernia Society Quality Collaborative database. All patients undergoing elective, open VHR with synthetic mesh placement from January 2013 through January 2016 were identified within the Americas Hernia Society Quality Collaborative. Only patients with clean wounds were included. Patients were divided into 2 groups: onlay mesh placement with the use of adhesive and sublay mesh placement. The association of mesh location with 30-day wound events was investigated using a matched analysis. A total of 1,854 patients met inclusion criteria; 1,761 (95.0%) underwent sublay mesh placement and 93 (5.0%) underwent onlay mesh placement with the use of adhesive. A 2:1 sublay to onlay matched analysis was performed based on factors previously shown to influence wound events after VHR. After matching, both groups had a lower mean Ventral Hernia Working Group grade and fewer associated comorbidities. There was no statistically significant difference between the sublay and onlay groups with respect to 30-day surgical site infections (2.9% vs 5.5%; p = 0.30), surgical site occurrences (15.2% vs 7.7%; p = 0.08), or surgical site occurrences requiring procedural intervention (8.2% vs 5.5%; p = 0.42). Ventral hernia repair with onlay mesh placement is a safe alternative to VHR with sublay mesh placement in low-risk patients. Additional studies are needed to determine the long-term mesh outcomes and recurrence rates in both of these groups. Copyright © 2017 American College of

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

    Directory of Open Access Journals (Sweden)

    Paulo Palma

    2010-04-01

    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.

  18. Mesh refinement strategy for optimal control problems

    Science.gov (United States)

    Paiva, L. T.; Fontes, F. A. C. C.

    2013-10-01

    Direct methods are becoming the most used technique to solve nonlinear optimal control problems. Regular time meshes having equidistant spacing are frequently used. However, in some cases these meshes cannot cope accurately with nonlinear behavior. One way to improve the solution is to select a new mesh with a greater number of nodes. Another way, involves adaptive mesh refinement. In this case, the mesh nodes have non equidistant spacing which allow a non uniform nodes collocation. In the method presented in this paper, a time mesh refinement strategy based on the local error is developed. After computing a solution in a coarse mesh, the local error is evaluated, which gives information about the subintervals of time domain where refinement is needed. This procedure is repeated until the local error reaches a user-specified threshold. The technique is applied to solve the car-like vehicle problem aiming minimum consumption. The approach developed in this paper leads to results with greater accuracy and yet with lower overall computational time as compared to using a time meshes having equidistant spacing.

  19. 7th International Meshing Roundtable '98

    Energy Technology Data Exchange (ETDEWEB)

    Eldred, T.J.

    1998-10-01

    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.

  20. Laparoscopic Pelvic Floor Repair Using Polypropylene Mesh

    Directory of Open Access Journals (Sweden)

    Shih-Shien Weng

    2008-09-01

    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.

  1. Decreased cervical cancer cell adhesion on nanotubular titanium for the treatment of cervical cancer

    OpenAIRE

    Crear J; Kummer KM; Webster TJ

    2013-01-01

    Jara Crear, Kim M Kummer, Thomas J Webster School of Engineering, Brown University, Providence, RI, USA Abstract: Cervical cancer can be treated by surgical resection, chemotherapy, and/or radiation. Titanium biomaterials have been suggested as a tool to help in the local delivery of chemotherapeutic agents and/or radiation to cervical cancer sites. However, current titanium medical devices used for treating cervical cancer do not by themselves possess any anticancer properties; such devices...

  2. A comparison of tetrahedral mesh improvement techniques

    Energy Technology Data Exchange (ETDEWEB)

    Freitag, L.A.; Ollivier-Gooch, C. [Argonne National Lab., IL (United States). Mathematics and Computer Science Div.

    1996-12-01

    Automatic mesh generation and adaptive refinement methods for complex three-dimensional domains have proven to be very successful tools for the efficient solution of complex applications problems. These methods can, however, produce poorly shaped elements that cause the numerical solution to be less accurate and more difficult to compute. Fortunately, the shape of the elements can be improved through several mechanisms, including face-swapping techniques that change local connectivity and optimization-based mesh smoothing methods that adjust grid point location. The authors consider several criteria for each of these two methods and compare the quality of several meshes obtained by using different combinations of swapping and smoothing. Computational experiments show that swapping is critical to the improvement of general mesh quality and that optimization-based smoothing is highly effective in eliminating very small and very large angles. The highest quality meshes are obtained by using a combination of swapping and smoothing techniques.

  3. Surgical Navigation

    DEFF Research Database (Denmark)

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

    2017-01-01

    were identified in the field of traumatology. Treatment of complex orbital fractures was considerably improved by the use of SN compared with traditionally treated control groups. Conclusions: SN seems to be a very promising addition to the surgical toolkit. Planning details of the surgical procedure...... in a 3-dimensional virtual environment and execution with real-time guidance can significantly improve precision. Among factors to be considered are the financial investments necessary and the learning curve....

  4. Characteristics of Mesh Wave Impedance in FDTD Non-Uniform Mesh

    Institute of Scientific and Technical Information of China (English)

    REN Wu; LIU Bo; GAO Ben-qing

    2005-01-01

    In order to increase the evaluating precision of mesh reflection wave, the mesh wave impedance(MWI) is extended to the non-uniform mesh in 1-D and 2-D cases for the first time on the basis of the Yee's positional relation for electromagnetic field components. Lots of characteristics are obtained for different mesh sizes and frequencies. Then the reflection coefficient caused by the non-uniform mesh can be calculated according to the theory of equivalent transmission line. By comparing it with that calculated by MWI in the uniform mesh, it is found that the evaluating error can be largely reduced and is in good agreement with that directly computed by FDTD method. And this extension of MWI can be used in the error analysis of complex mesh.

  5. Update on Development of Mesh Generation Algorithms in MeshKit

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-30

    MeshKit uses a graph-based design for coding all its meshing algorithms, which includes the Reactor Geometry (and mesh) Generation (RGG) algorithms. This report highlights the developmental updates of all the algorithms, results and future work. Parallel versions of algorithms, documentation and performance results are reported. RGG GUI design was updated to incorporate new features requested by the users; boundary layer generation and parallel RGG support were added to the GUI. Key contributions to the release, upgrade and maintenance of other SIGMA1 libraries (CGM and MOAB) were made. Several fundamental meshing algorithms for creating a robust parallel meshing pipeline in MeshKit are under development. Results and current status of automated, open-source and high quality nuclear reactor assembly mesh generation algorithms such as trimesher, quadmesher, interval matching and multi-sweeper are reported.

  6. Clinical Analysis of Internal Fixation Treatment of Intra-articular Calcaneal Fractures with Titanium Plate.

    Science.gov (United States)

    Chen, Xiao-Dong; Zhang, Chang-Chun; Li, Zhao-Cheng; Zhang, Heng; Zhou, Xin-She; Deng, Min

    2015-05-01

    To explore the clinical effect of internal fixation treatment of intra-articular calcaneal fractures with titanium plate, we used open reduction and internal fixation with titanium plate to 48 treated feet from 42 patients with intra-articular calcaneal fractures. The efficacy of surgical treatment was evaluated based on assessment of pain, function, and line of force aspects according to the American Orthopedic Foot and Ankle Society scoring system. Our data show that internal fixation with titanium plate is an effective treatment for calcaneal fractures. It provides satisfactory reduction, reliable fixation, and early rehabilitation.

  7. Automatic Mesh Generation of Hybrid Mesh on Valves in Multiple Positions in Feedline Systems

    Science.gov (United States)

    Ross, Douglass H.; Ito, Yasushi; Dorothy, Fredric W.; Shih, Alan M.; Peugeot, John

    2010-01-01

    Fluid flow simulations through a valve often require evaluation of the valve in multiple opening positions. A mesh has to be generated for the valve for each position and compounding. The problem is the fact that the valve is typically part of a larger feedline system. In this paper, we propose to develop a system to create meshes for feedline systems with parametrically controlled valve openings. Herein we outline two approaches to generate the meshes for a valve in a feedline system at multiple positions. There are two issues that must be addressed. The first is the creation of the mesh on the valve for multiple positions. The second is the generation of the mesh for the total feedline system including the valve. For generation of the mesh on the valve, we will describe the use of topology matching and mesh generation parameter transfer. For generation of the total feedline system, we will describe two solutions that we have implemented. In both cases the valve is treated as a component in the feedline system. In the first method the geometry of the valve in the feedline system is replaced with a valve at a different opening position. Geometry is created to connect the valve to the feedline system. Then topology for the valve is created and the portion of the topology for the valve is topology matched to the standard valve in a different position. The mesh generation parameters are transferred and then the volume mesh for the whole feedline system is generated. The second method enables the user to generate the volume mesh on the valve in multiple open positions external to the feedline system, to insert it into the volume mesh of the feedline system, and to reduce the amount of computer time required for mesh generation because only two small volume meshes connecting the valve to the feedline mesh need to be updated.

  8. Surgical resection and reconstruction for primary malignant sternal tumor.

    Science.gov (United States)

    Hirai, Shinji; Nobuto, Hiroaki; Yokota, Kazunori; Matsuura, Yosuke; Uegami, Shinnosuke; Sato, Katsutoshi; Mitsui, Norimasa; Sugita, Takashi; Hamanaka, Yoshiharu

    2009-06-01

    We report a very rare and successful surgery for primary malignant tumor of the sternum. A 73-year-old male, previously healthy, was admitted to our hospital because a chest computed tomography scan detected an abnormal shadow that suggested a sternal tumor destroying part of the sternum body. Aspiration needle biopsy demonstrated a primary sternal chondrosarcoma measuring 3 x 4 cm in diameter. The sternum below the second intercostal space was resected along with a 1-cm width of cartilage below the third rib on each side. Sternal reconstruction was performed with Composix mesh, titanium mesh, and Marlex mesh, using a right pectoralis major muscle flap translation. The patient was extubated just after surgery, and the postoperative course was uneventful. This procedure may be useful for repairing the detect after wide sternotomy.

  9. Colovesical fistula following an open preperitoneal "Kugel" mesh repair of an inguinal hernia.

    Science.gov (United States)

    Barreto, S G; Schoemaker, D; Siddins, M; Wattchow, D

    2009-12-01

    Erosion of the "Kugel" mesh into intraperitoneal organs has not been previously reported in the medical literature. We report such an occurrence in a 54-year-old male, 4 years following a "Kugel" preperitoneal repair of a left-sided inguinal hernia. The patient presented with septicaemia, pneumaturia and left iliac fossa pain. His computed tomography (CT) scan indicated the presence of gas in the bladder and a thickened loop of sigmoid colon attached to the region of the dome of the bladder. Colonoscopy showed some scattered diverticula in the sigmoid colon but no tumour. On surgical exploration, the "Kugel" mesh was found to erode the sigmoid colon and the bladder wall, leading to a colovesical fistula. An anterior resection of the rectum with removal of the mesh with closure of the bladder wall defect was performed.

  10. [Laparoscopic inguinal hernia repair "IPOM" with Dual-Mesh].

    Science.gov (United States)

    Catani, M; De Milito, R; Materia, A; Chiaretti, M; Spaziani, E; Manili, G; Simi, M

    2003-01-01

    The authors report their experience on laparoscopic hernioplasty using the Intraperitoneal Onlay Mesh Repair (IPOM) in 56 patients. 34 patients had a bilateral hernia, 6 of which were recurrent and 22 had a monolateral hernia, of which 9 had recurrent hernia. Overall, a total of 90 hernias were treated. The hernia repair was performed utilizing "GORE-TEX DualMesh Plus biomaterial with holes" in the first 32 cases and the latest "...Corduroy" type in the remaining 24 cases. The prostheses were fixed with titanium spiral tacks (Protack, AutoSuture, Tyco Healthcare). No intraoperative complications occurred and no conversion was necessary. Five minor post-operative complications (5.5%), 2 seromas and 3 transient paresthesias, were observed. Four patients (7.1%) needed analgesics after the first 24 hours. Mean hospital stay was 36 hours, with a minimum of 24 and a maximum of 48. Mean resumption of normal activity was 8 days with return to work within two weeks. At an average 18 months follow-up, 3 recurrences were recorded (3.3%). The results of this study as well as the meta-analysis of the series presented in the Literature, indicate that the IPOM may be a feasible, safe and effective procedure in the treatment of recurrent and bilateral hernias or when a hernia repair is performed during other laparoscopic procedures. The IPOM has infact been shown to be faster and easier than the other more commonly performed laparoscopic hernioplasties (TAPP and TEP). These data may also suggest to utilize this technique in particular cases of primitive hernia such as very active young males or heavy duty workers. However the limited series and the short follow-up ask for randomized prospective long term studies to definitely ascertain the true incidence of recurrence and therefore the effectiveness of this attractive procedure.

  11. Quadratically consistent projection from particles to mesh

    CERN Document Server

    Duque, Daniel

    2016-01-01

    The advantage of particle Lagrangian methods in computational fluid dynamics is that advection is accurately modeled. However, this complicates the calculation of space derivatives. If a mesh is employed, it must be updated at each time step. On the other hand, fixed mesh, Eulerian, formulations benefit from the mesh being defined at the beginning of the simulation, but feature non-linear advection terms. It therefore seems natural to combine the two approaches, using a fixed mesh to perform calculations related to space derivatives, and using the particles to advect the information with time. The idea of combining Lagrangian particles and a fixed mesh goes back to Particle-in-Cell methods, and is here considered within the context of the finite element method (FEM) for the fixed mesh, and the particle FEM (pFEM) for the particles. Our results, in agreement with recent works, show that interpolation ("projection") errors, especially from particles to mesh, are the culprits of slow convergence of the method if...

  12. Biomimetic synthesis of interlaced mesh structures TiO{sub 2} nanofibers with enhanced photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guanghui [Tianjin Key Laboratory of Applied Catalysis Science and Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 China (China); Collaborative Innovation Center of Chemical Science and Engineering(Tianjin), Tianjin 300072 China (China); Zhang, Tianyong, E-mail: tyzhang@tju.edu.cn [Tianjin Key Laboratory of Applied Catalysis Science and Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 China (China); Collaborative Innovation Center of Chemical Science and Engineering(Tianjin), Tianjin 300072 China (China); Li, Bin, E-mail: libin@tju.edu.cn [Tianjin Key Laboratory of Applied Catalysis Science and Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 China (China); Collaborative Innovation Center of Chemical Science and Engineering(Tianjin), Tianjin 300072 China (China); Zhang, Xia; Chen, Xingwei [Tianjin Key Laboratory of Applied Catalysis Science and Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 China (China)

    2016-05-25

    A facile and economical method assisted by PPs (the spongy white peels of pomelo peel) was applied for preparing interlaced mesh structures TiO{sub 2} nanofibers by a liquid impregnation method followed by a calcination process in this study. And the as-prepared materials were comprehensively investigated by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectra, UV-vis diffuse reflectance spectroscopy, photoluminescence spectra and N{sub 2} adsorption-desorption. The resultant TiO{sub 2} materials exhibit unique morphology, in which the curly nanofibers with the diameter about 90 nm interweave each other for assembling hierarchical mesh structures and there are abundant grooves on the surface of the nanofibers. During the bio-inspired synthetic process, the PPs play important roles as template and induction for forming the hierarchical mesh structures of TiO{sub 2} nanofibers. Furthermore, some of the as-prepared TiO{sub 2} samples exhibit 99% degradation rate for methyl orange in 30 min under UV light irradiation, which can be ascribed to the larger surface area and the unique hierarchical mesh structures. In addition, the stability tests of 5 cycling runs of the photocatalysts indicate that the as-prepared TiO{sub 2} nanofibers can be applied as a practical photocatalyst for degrading organic dyes under UV light irradiation. Therefore, hopefully, the strategy for preparing the TiO{sub 2} nanofibers can be extended to design many more powerful photocatalysts for the environmental remediation in the near future. - Graphical abstract: The TiO{sub 2} nanofibers with interlaced mesh structures were prepared with PPs (the spongy white peels of pomelo peel) as the reactive substrate and directing template, and titanium tetrachloride (TiCl{sub 4}) as titanium resource. And the as-prepared TiO{sub 2} samples exhibit highly photocatalytic activity and good stability for degrading methyl orange under UV light irradiation. - Highlights: • A

  13. High-temperature Titanium Alloys

    Directory of Open Access Journals (Sweden)

    A.K. Gogia

    2005-04-01

    Full Text Available The development of high-temperature titanium alloys has contributed significantly to the spectacular progress in thrust-to-weight ratio of the aero gas turbines. This paper presents anoverview on the development of high-temperature titanium alloys used in aero engines and potential futuristic materials based on titanium aluminides and composites. The role of alloychemistry, processing, and microstructure, in determining the mechanical properties of titanium alloys is discussed. While phase equilibria and microstructural stability consideration haverestricted the use of conventional titanium alloys up to about 600 "C, alloys based on TiPl (or,, E,AINb (0, TiAl (y, and titaniumltitanium aluminides-based composites offer a possibility ofquantum jump in the temperature capability of titanium alloys.

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

    KAUST Repository

    Zhang, Fang

    2011-02-01

    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. Hydrolytically stable titanium-45

    DEFF Research Database (Denmark)

    Severin, Gregory; Fonslet, Jesper; Zhuravlev, Fedor

    2014-01-01

    Introduction Titanium-45, a candidate PET isotope, is under-employed largely because of the challenging aqueous chemistry of Ti(IV). The propensity for hydrolysis of Ti(IV) compounds makes radio-labeling difficult and excludes 45Ti from use in bio-conjugate chemistry. This is unfortunate because...... metal-based chemotherapeutics such as cisplatin. The aim of our work has been to produce the radioactive analogue of one of these Ti(IV)-salan compounds, Ti-salan-dipic [2], which has hydro-lytic stability on the order of weeks. Not only will this allow us to shed some light on the still un......-known mechanism of antiproliferative action of titanium-based chemotherapeutics, but it will also make progress toward bioconjugate 45Ti PET tracers. In the current abstract, we present some of the methods we are using to separate 45Ti from irradiated Sc, and subsequent labeling conditions. Material and Methods...

  16. H(curl) Auxiliary Mesh Preconditioning

    Energy Technology Data Exchange (ETDEWEB)

    Kolev, T V; Pasciak, J E; Vassilevski, P S

    2006-08-31

    This paper analyzes a two-level preconditioning scheme for H(curl) bilinear forms. The scheme utilizes an auxiliary problem on a related mesh that is more amenable for constructing optimal order multigrid methods. More specifically, we analyze the case when the auxiliary mesh only approximately covers the original domain. The latter assumption is important since it allows for easy construction of nested multilevel spaces on regular auxiliary meshes. Numerical experiments in both two and three space dimensions illustrate the optimal performance of the method.

  17. Engagement of Metal Debris into Gear Mesh

    Science.gov (United States)

    handschuh, Robert F.; Krantz, Timothy L.

    2010-01-01

    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.

  18. Application of mesh network radios to UGS

    Science.gov (United States)

    Calcutt, Wade; Jones, Barry; Roeder, Brent

    2008-04-01

    During the past five years McQ has been actively pursuing integrating and applying wireless mesh network radios as a communications solution for unattended ground sensor (UGS) systems. This effort has been rewarded with limited levels of success and has ultimately resulted in a corporate position regarding the use of mesh network radios for UGS systems. A discussion into the background of the effort, the challenges of implementing commercial off-the-shelf (COTS) mesh radios with UGSs, the tradeoffs involved, and an overview of the future direction is presented.

  19. Mesh Optimization for Ground Vehicle Aerodynamics

    OpenAIRE

    Adrian Gaylard; Essam F Abo-Serie; Nor Elyana Ahmad

    2010-01-01

    Mesh optimization strategy for estimating accurate drag of a ground vehicle is proposed based on examining the effect of different mesh parameters.  The optimized mesh parameters were selected using design of experiment (DOE) method to be able to work in a...

  20. Rigidity Constraints for Large Mesh Deformation

    Institute of Scientific and Technical Information of China (English)

    Yong Zhao; Xin-Guo Liu; Qun-Sheng Peng; Hu-Jun Bao

    2009-01-01

    It is a challenging problem of surface-based deformation to avoid apparent volumetric distortions around largely deformed areas. In this paper, we propose a new rigidity constraint for gradient domain mesh deformation to address this problem. Intuitively the proposed constraint can be regarded as several small cubes defined by the mesh vertices through mean value coordinates. The user interactively specifies the cubes in the regions which are prone to volumetric distortions, and the rigidity constraints could make the mesh behave like a solid object during deformation. The experimental results demonstrate that our constraint is intuitive, easy to use and very effective.

  1. SURFACE MESH PARAMETERIZATION WITH NATURAL BOUNDARY

    Institute of Scientific and Technical Information of China (English)

    Ye Ming; Zhu Xiaofeng; Wang Chengtao

    2003-01-01

    Using the projected curve of surface mesh boundary as parameter domain border, linear mapping parameterization with natural boundary is realized. A fast algorithm for least squares fitting plane of vertices in the mesh boundary is proposed. After the mesh boundary is projected onto the fitting plane, low-pass filtering is adopted to eliminate crossovers, sharp corners and cavities in the projected curve and convert it into an eligible convex parameter domain boundary. In order to facilitate quantitative evaluations of parameterization schemes, three distortion-measuring formulae are presented.

  2. Establishment of Epithelial Attachment on Titanium Surface Coated with Platelet Activating Peptide

    Science.gov (United States)

    Sugawara, Shiho; Maeno, Masahiko; Lee, Cliff; Nagai, Shigemi; Kim, David M.; Da Silva, John; Kondo, Hisatomo

    2016-01-01

    The aim of this study was to produce epithelial attachment on a typical implant abutment surface of smooth titanium. A challenging complication that hinders the success of dental implants is peri-implantitis. A common cause of peri-implantitis may results from the lack of epithelial sealing at the peri-implant collar. Histologically, epithelial sealing is recognized as the attachment of the basement membrane (BM). BM-attachment is promoted by activated platelet aggregates at surgical wound sites. On the other hand, platelets did not aggregate on smooth titanium, the surface typical of the implant abutment. We then hypothesized that epithelial BM-attachment was produced when titanium surface was modified to allow platelet aggregation. Titanium surfaces were coated with a protease activated receptor 4-activating peptide (PAR4-AP). PAR4-AP coating yielded rapid aggregation of platelets on the titanium surface. Platelet aggregates released robust amount of epithelial chemoattractants (IGF-I, TGF-β) and growth factors (EGF, VEGF) on the titanium surface. Human gingival epithelial cells, when they were co-cultured on the platelet aggregates, successfully attached to the PAR4-AP coated titanium surface with spread laminin5 positive BM and consecutive staining of the epithelial tight junction component ZO1, indicating the formation of complete epithelial sheet. These in-vitro results indicate the establishment of epithelial BM-attachment to the titanium surface. PMID:27741287

  3. Titanium Carbide: Nanotechnology, Properties, Application

    OpenAIRE

    Galevsky, G. V.; Rudneva, V. V.; Garbuzova, A. K.; Valuev, Denis Viktorovich

    2015-01-01

    The paper develops scientific and technological bases for fabrication of titanium carbide which is a nanocomponent of composite materials. The authors determine optimum technology specifications and the main titanium carbide properties: fineness of titaniferous raw materials, carbide-forming agent quantity, set temperature of plasma flow, tempering temperature, titanium carbide yield, productivity, specific surface, size and shape of particles. The paper includes equations to describe how the...

  4. Titanium Nitride Cermets

    Science.gov (United States)

    1952-07-01

    C ermets 7 Effect of Amount of Metal on Strength of TiN-Ni-Cr....26 Cerme ts S Effect of Amount of Metal on Strength of TiN-Co-Cr....27 Cermets 9...Figures 7 and 8. Titanium Nitride-Nickel-Chromium Cerme ts From Figure 7, it can be seen that 2900OF was the better firing temperature. The 20% metal

  5. Surgical mini-incision treatment of patent ductus arteriosus of premature infants with titanium clip in 110 cases%床旁微创小切口钛夹闭合早产儿动脉导管110例临床分析

    Institute of Scientific and Technical Information of China (English)

    付松; 封志纯

    2013-01-01

    Objective To investigate the clinical effects of surgical small incision treatment of patent ductus arteriosus (PDA) in premature infants with titanium clip.Methods One hundred children received and cured by our hospital from January 2010 to January 2013 were divided into two groups.Group A:body weight > 1.5 kg of patent ductus arteriosus (PDA),71 cases of premature children; group B:body weight < 1.5 kg of low body weight preterm the children PDA,29 cases.The operations were performed in the newborn intensive care unit (NICU).The patient was placed in a lateral position with the left arm abduction under general anesthesia.A 1.5-2.5 cm long posterolateral mini-thoracotomy was made and the pleural cavity was entered via the 2-3rd intercostal space.The PDA was closed with two titanium clips.Results Ninety-nine cases were cured,1 died.2 residual shunt postoperatively.One patient on postoperative 5 day was found wound infected,wound healing after the use of antibiotics by intravenous.There was no significant difference in incidence of postoperative complications and mortality rate between group A and group B (P > 0.05).Majority of children successfully weaned from the ventilator due to the rapid improvement of hemodynamics and lung conditions.In group B,mechanical ventilation time (12.6 ± 7.5) d and postoperative hospital stay (21.0 ± 15.4) d was significantly longer than group A ((9.6 ± 4.2) d and (12.0 ± 10.8) d),the difference between the two groups was significant (t =7.35,9.12,P < 0.05).Conclusion (1) It is a viable treatment that bedside minimally invasive titanium clip closed ductus arteriosus in preterm children PDA.(2) As the treatment of low body weight premature children is poor,the tolerance of the surgical trauma of the surgery as a minimally invasive,simple method is particularly suitable for low body weight premature children PDA.%目的 探讨床旁微创小切口钛夹闭合早产儿动脉导管的临床疗效.方法 将2010年1月至2013

  6. Graphene-coated meshes for electroactive flow control devices utilizing two antagonistic functions of repellency and permeability

    Science.gov (United States)

    Tabassian, Rassoul; Oh, Jung-Hwan; Kim, Sooyeun; Kim, Donggyu; Ryu, Seunghwa; Cho, Seung-Min; Koratkar, Nikhil; Oh, Il-Kwon

    2016-10-01

    The wettability of graphene on various substrates has been intensively investigated for practical applications including surgical and medical tools, textiles, water harvesting, self-cleaning, oil spill removal and microfluidic devices. However, most previous studies have been limited to investigating the intrinsic and passive wettability of graphene and graphene hybrid composites. Here, we report the electrowetting of graphene-coated metal meshes for use as electroactive flow control devices, utilizing two antagonistic functions, hydrophobic repellency versus liquid permeability. Graphene coating was able to prevent the thermal oxidation and corrosion problems that plague unprotected metal meshes, while also maintaining its hydrophobicity. The shapes of liquid droplets and the degree of water penetration through the graphene-coated meshes were controlled by electrical stimuli based on the functional control of hydrophobic repellency and liquid permeability. Furthermore, using the graphene-coated metal meshes, we developed two active flow devices demonstrating the dynamic locomotion of water droplets and electroactive flow switching.

  7. Prevention of lung cancer recurrence using cisplatin-loaded superhydrophobic nanofiber meshes.

    Science.gov (United States)

    Kaplan, Jonah A; Liu, Rong; Freedman, Jonathan D; Padera, Robert; Schwartz, John; Colson, Yolonda L; Grinstaff, Mark W

    2016-01-01

    For early stage lung cancer patients, local cancer recurrence after surgical resection is a significant concern and stems from microscopic disease left behind after surgery. Here we apply a local drug delivery strategy to combat local lung cancer recurrence after resection using non-woven, biodegradable nanofiber meshes loaded with cisplatin. The meshes are fabricated using a scalable electrospinning process from two biocompatible polymers--polycaprolactone and poly(glycerol monostearate-co-caprolactone)--to afford favorable mechanical properties for use in a dynamic tissue such as the lung. Owing to their rough nanostructure and hydrophobic polymer composition, these meshes exhibit superhydrophobicity, and it is this non-wetting nature that sustains the release of cisplatin in a linear fashion over ∼90 days, with anti-cancer efficacy demonstrated using an in vitro Lewis Lung carcinoma (LLC) cell assay. The in vivo evaluation of cisplatin-loaded superhydrophobic meshes in the prevention of local cancer recurrence in a murine model of LLC surgical resection demonstrated a statistically significant increase (p = 0.0006) in median recurrence-free survival to >23 days, compared to standard intraperitoneal cisplatin therapy of equivalent dose. These results emphasize the importance of supplementing cytoreductive surgery with local drug delivery strategies to improve prognosis for lung cancer patients undergoing tumor resection. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. [Complications associated with the use of polypropylene mesh in women under colposacropexy].

    Science.gov (United States)

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

    2015-10-01

    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.

  9. Titanium Carbide: Nanotechnology, Properties, Application

    Science.gov (United States)

    Galevsky, G. V.; Rudneva, V. V.; Garbuzova, A. K.; Valuev, D. V.

    2015-09-01

    The paper develops scientific and technological bases for fabrication of titanium carbide which is a nanocomponent of composite materials. The authors determine optimum technology specifications and the main titanium carbide properties: fineness of titaniferous raw materials, carbide-forming agent quantity, set temperature of plasma flow, tempering temperature, titanium carbide yield, productivity, specific surface, size and shape of particles. The paper includes equations to describe how the major specifications of the fabrication technique influence the content of titanium carbide and free carbon in the end product.

  10. Paravesical haematoma following placement of an isolated anterior mesh for cystocele repair

    Directory of Open Access Journals (Sweden)

    Sparić Radmila

    2013-01-01

    Full Text Available Introduction. Pelvic organ prolapse is a substantial health problem for women around the world. Given the limitations of traditional surgery in the reconstruction of normal vaginal anatomy and function in genitourinary prolapse, various synthetic implants have been developed for surgical repair. Mesh procedures are gaining in popularity, encouraged by preliminary data. Although minimally invasive and relatively safe, serious complications following these procedures have been described. Case report. We presented a patient who had underwent an isolated anterior mesh procedure and developed postoperative haematoma which required surgical intervention. Conclusion. This report suggests that minimally invasive urogynecological procedures could result in significant complications. Thus, surgeons should be familiar with effective interventions in order to manage them.

  11. Chemotherapy-induced enterocutaneous fistula after perineal hernia repair using a biological mesh: a case report

    Directory of Open Access Journals (Sweden)

    Eriksen MH

    2014-01-01

    Full Text Available MH Eriksen, O Bulut Department of Surgical Gastroenterology, Hvidovre University Hospital, University of Copenhagen, Copenhagen, Denmark Abstract: This is the first reported case of an enterocutaneous fistula as a late complication to reconstruction of the pelvic floor with a Permacol™ mesh after a perineal hernia. A 70-year-old man had a reconstruction of the pelvic floor with a biological mesh because of a perineal hernia after laparoscopic abdominoperineal resection. Nine months after the perineal hernia operation, the patient had multiple metastases in both lungs and liver. The patient underwent chemotherapy, including bevacizumab, irinotecan, calcium folinate, and fluorouracil. Six weeks into chemotherapy, the patient developed signs of sepsis and complained of pain from the right buttock. Ultrasound examination revealed an abscess, which was drained, guided by ultrasound. A computed tomography scan showed a subcutaneous abscess cavity located in the right buttock with communication to the small bowel. Operative findings confirmed a perineal fistula from the distal ileum to perineum. A resection of the small bowel with primary anastomosis was performed. The postoperative course was complicated by fluid and electrolyte disturbances, but the patient was stabilized and finally discharged to a hospice for terminal care after 28 days of hospital stay. It seems that hernia repairs with biological meshes have lower erosion and infection rates compared with synthetic meshes, and so far, evidence suggests that biological grafts are safe and effective in the treatment of pelvic floor reconstruction. There have been no reports of enteric fistulas after pelvic reconstruction with biological meshes. However, the development of intestinal fistulas after chemotherapy with bevacizumab has been described in the literature. Our case report supports this association between bevacizumab and fistula formation among rectal cancer patients, as symptoms of a

  12. Designation and development of biomedical Ti alloys with finer biomechanical compatibility in long-term surgical implants

    Science.gov (United States)

    Yu, Zhen-Tao; Zhang, Ming-Hua; Tian, Yu-Xing; Cheng, Jun; Ma, Xi-Qun; Liu, Han-Yuan; Wang, Chang

    2014-09-01

    Developing the new titanium alloys with excellent biomechanical compatibility has been an important research direction of surgical implants materials. Present paper summarizes the international researches and developments of biomedical titanium alloys. Aiming at increasing the biomechanical compatibility, it also introduces the exploration and improvement of alloy designing, mechanical processing, microstructure and phase transformation, and finally outlines the directions for scientific research on the biomedical titanium alloys in the future.

  13. Is Mesh Becoming More Popular? Dilemmas in Urogynecology: A National Survey

    Directory of Open Access Journals (Sweden)

    Alexander Condrea

    2012-01-01

    Full Text Available The use of vaginal mesh in pelvic organ prolapse (POP repair surgery has become more common in recent years. The purpose of the current study was to evaluate the common practice of Israeli urogynecologists, and to determine whether surgical practice has changed over the last two years. Methods. In 2009 and again in 2011, a survey was mailed to all urogynecologists affiliated with an academic institute in Israel. The survey consisted of 7 Likert-scale items and 3 open questions; the latter inquired about preferred type of surgery in three clinical scenarios. Results. Of 22 practitioners, 15 responded to the survey. The number of urogynecologists who reported using vaginal mesh for the repair of primary POP increased from 47 to 67% from 2009 to 2011. The number who would not use vaginal mesh in POP repair of elderly patients dropped from 60 to 3%. Finally, for the treatment of a 35-year-old patient with stage III uterine prolapse who desired to preserve fertility, 13% recommended the used vaginal mesh in 2009 compared with 47% in 2011. Conclusion. A survey of practitioners shows that the use of vaginal mesh for the repair of primary and recurrent pelvic organ prolapse has become more common among Israeli urogynecologists.

  14. INCIDENTAL LEIOMYOMA IN MESH HERNIOPLASTY

    Directory of Open Access Journals (Sweden)

    Asha

    2013-05-01

    Full Text Available ABSTRACT: Incidental finding of leiomyoma is rare finding and can mimic an inguinal hernia or both can occur at a time. Very small mass beside he rnia sac identified during exploration of the inguinal canal. Inguinal hernia in females is less common compared to males, but more common than the femoral hernia. Beside the sac there may b e other structures, which have been reported like lipoma of cord, lymph node. In our hospital we have come across this case, and would like to report. Confirmatory diagnosis is established by hi stopathology. Surgical excision is the curative treatment

  15. Assignment of fields from particles to mesh

    CERN Document Server

    Duque, Daniel

    2016-01-01

    In Computational Fluid Dynamics there have been many attempts to combine the power of a fixed mesh on which to carry out spatial calculations with that of a set of particles that moves following the velocity field. These ideas indeed go back to Particle-in-Cell methods, proposed about 60 years ago. Of course, some procedure is needed to transfer field information between particles and mesh. There are many possible choices for this "assignment", or "projection". Several requirements may guide this choice. Two well-known ones are conservativity and stability, which apply to volume integrals of the fields. An additional one is here considered: preservation of information. This means that mesh interpolation, followed by mesh assignment, should leave the field values invariant. The resulting methods are termed "mass" assignments due to their strong similarities with the Finite Element Method. We test several procedures, including the well-known FLIP, on three scenarios: simple 1D convection, 2D convection of Zales...

  16. Shape space exploration of constrained meshes

    KAUST Repository

    Yang, Yongliang

    2011-01-01

    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.

  17. LR: Compact connectivity representation for triangle meshes

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-01-28

    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.

  18. Shape space exploration of constrained meshes

    KAUST Repository

    Yang, Yongliang

    2011-12-12

    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.

  19. Spacetime Meshing for Discontinuous Galerkin Methods

    CERN Document Server

    Thite, Shripad Vidyadhar

    2008-01-01

    Spacetime discontinuous Galerkin (SDG) finite element methods are used to solve such PDEs involving space and time variables arising from wave propagation phenomena in important applications in science and engineering. To support an accurate and efficient solution procedure using SDG methods and to exploit the flexibility of these methods, we give a meshing algorithm to construct an unstructured simplicial spacetime mesh over an arbitrary simplicial space domain. Our algorithm is the first spacetime meshing algorithm suitable for efficient solution of nonlinear phenomena in anisotropic media using novel discontinuous Galerkin finite element methods for implicit solutions directly in spacetime. Given a triangulated d-dimensional Euclidean space domain M (a simplicial complex) and initial conditions of the underlying hyperbolic spacetime PDE, we construct an unstructured simplicial mesh of the (d+1)-dimensional spacetime domain M x [0,infinity). Our algorithm uses a near-optimal number of spacetime elements, ea...

  20. Metal Mesh Filters for Terahertz Receivers Project

    Data.gov (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...

  1. Adaptive sampling for mesh spectrum editing

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiang-jun; ZHANG Hong-xin; BAO Hu-jun

    2006-01-01

    A mesh editing framework is presented in this paper, which integrates Free-Form Deformation (FFD) and geometry signal processing. By using simplified model from original mesh, the editing task can be accomplished with a few operations. We take the deformation of the proxy and the position coordinates of the mesh models as geometry signal. Wavelet analysis is employed to separate local detail information gracefully. The crucial innovation of this paper is a new adaptive regular sampling approach for our signal analysis based editing framework. In our approach, an original mesh is resampled and then refined iteratively which reflects optimization of our proposed spectrum preserving energy. As an extension of our spectrum editing scheme,the editing principle is applied to geometry details transferring, which brings satisfying results.

  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. Obtuse triangle suppression in anisotropic meshes

    KAUST Repository

    Sun, Feng

    2011-12-01

    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.

  4. [Our experiences with the use of 3-dimensional meshes to prevent and to repair parastomal hernias].

    Science.gov (United States)

    Jánó, Zoltán; Mohos, Elemér; Réti, György; Kovács, Tamás; Mohay, József; Berki, Csaba; Horváth, Sándor; Bene, Krisztina; Horzov, Myroslav; Bognár, Gábor; Sándor, Gábor; Szenkovits, Péter; Mohos, Petra; Tornai, Gábor; Nagy, Attila

    2016-12-01

    Albeit there is decreasing tendency nowadays for stoma construction, if it still happens, parastomal herniation might occur in up to 50% of cases afterwards. One third of the cases requires surgical correction, not rarely as an emergency. The different methods of repair can be quite demanding and the complication rates are high. From 2003 we have started to use specially designed 3-dimensional meshes for the prevention and repair of parastomal hernias. From 1st of January 2012 to 1st of June 2016 we have used these devices within the framework of a prospective, controlled, randomized study enrolling the patients in preventive and repair arms. Until now mesh was implanted for prevention at the time of the index operation in 38 cases, (control group: 46 cases), and for repair in 14 cases (control group: 18 cases). Recruitment of the patients will end in 2017. The operations were performed by laparoscopic approach in 22 cases and by open approach in 62 cases in the preventive arm, and 6/26 cases in the repair arm respectively. Mean follow up period is 19.2 months in the mesh group and 22.6 months in the non mesh group in the preventive arm, and 25.9/20.4 months in the repair arm respectively. No statistical analysis was used to interpret these interim results in this paper, we intend to analyze our results at the end of the study. At this stage apparently there is no difference between the group of patients in terms of complications in both arms. Parastomal herniation was found in 18 cases (39.1%) in the non mesh group and in 3 cases (7.8%) in the mesh group in the preventive arm. Recurrency was noted in 8 cases (44%) in the non mesh group, and in 1 case (7.1%) in the mesh group in the repair arm. Our results correlate with other studies where mesh insertion was used to prevent and/or repair parastomal hernias. We attribute these results mainly to the special, 3-dimensional design of the meshes used by us. This construction was developed based on understanding the

  5. Removal of line artifacts on mesh boundary in computer generated hologram by mesh phase matching.

    Science.gov (United States)

    Park, Jae-Hyeung; Yeom, Han-Ju; Kim, Hee-Jae; Zhang, HuiJun; Li, BoNi; Ji, Yeong-Min; Kim, Sang-Hoo

    2015-03-23

    Mesh-based computer generated hologram enables realistic and efficient representation of three-dimensional scene. However, the dark line artifacts on the boundary between neighboring meshes are frequently observed, degrading the quality of the reconstruction. In this paper, we propose a simple technique to remove the dark line artifacts by matching the phase on the boundary of neighboring meshes. The feasibility of the proposed method is confirmed by the numerical and optical reconstruction of the generated hologram.

  6. Vaginal Calculus in a Woman With Mixed Urinary Incontinence and Vaginal Mesh Exposure.

    Science.gov (United States)

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

    2016-01-01

    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.

  7. The effect of mesh removal and selective neurectomy on persistent postherniotomy pain

    DEFF Research Database (Denmark)

    Aasvang, Eske K; Kehlet, Henrik

    2009-01-01

    SUMMARY BACKGROUND DATA AND OBJECTIVE: Persistent pain affects everyday activities in 5% to 8% of patients after groin hernia repair. Because previous reports on the effect of neurectomy and/or mesh removal suffer from methodological problems we performed a detailed prospective trial of the effec...... neurophysiologic assessment is recommended to identify patients who may or may not benefit from reoperation and to allocate patients to specific surgical and/or medical intervention....

  8. Chemical changes of titanium and titanium dioxide under electron bombardment

    OpenAIRE

    Romins Brasca; Luciana Ines Vergara; Mario César Guillermo Passeggi; Julio Ferrón

    2007-01-01

    The electron induced effect on the first stages of the titanium (Ti0) oxidation and titanium dioxide (Ti4+) chemical reduction processes has been studied by means of Auger electron spectroscopy. Using factor analysis we found that both processes are characterized by the appearance of an intermediate Ti oxidation state, Ti2O3 (Ti3+).

  9. Plasmonic Titanium Nitride Nanostructures via Nitridation of Nanopatterned Titanium Dioxide

    DEFF Research Database (Denmark)

    Guler, Urcan; Zemlyanov, Dmitry; Kim, Jongbum

    2017-01-01

    Plasmonic titanium nitride nanostructures are obtained via nitridation of titanium dioxide. Nanoparticles acquired a cubic shape with sharper edges following the rock-salt crystalline structure of TiN. Lattice constant of the resulting TiN nanoparticles matched well with the tabulated data. Energ...

  10. Chemical changes of titanium and titanium dioxide under electron bombardment

    Directory of Open Access Journals (Sweden)

    Romins Brasca

    2007-09-01

    Full Text Available The electron induced effect on the first stages of the titanium (Ti0 oxidation and titanium dioxide (Ti4+ chemical reduction processes has been studied by means of Auger electron spectroscopy. Using factor analysis we found that both processes are characterized by the appearance of an intermediate Ti oxidation state, Ti2O3 (Ti3+.

  11. MHD simulations on an unstructured mesh

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, H.R. [New York Univ., NY (United States); Park, W.; Belova, E.; Fu, G.Y. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Longcope, D.W. [Univ. of Montana, Missoula, MT (United States); Sugiyama, L.E. [Massachusetts Inst. of Tech., Cambridge, MA (United States)

    1998-12-31

    Two reasons for using an unstructured computational mesh are adaptivity, and alignment with arbitrarily shaped boundaries. Two codes which use finite element discretization on an unstructured mesh are described. FEM3D solves 2D and 3D RMHD using an adaptive grid. MH3D++, which incorporates methods of FEM3D into the MH3D generalized MHD code, can be used with shaped boundaries, which might be 3D.

  12. 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.......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....

  13. Vector field processing on triangle meshes

    OpenAIRE

    De Goes, Fernando; Desbrun, Mathieu; Tong, Yiying

    2015-01-01

    While scalar fields on surfaces have been staples of geometry processing, the use of tangent vector fields has steadily grown in geometry processing over the last two decades: they are crucial to encoding directions and sizing on surfaces as commonly required in tasks such as texture synthesis, non-photorealistic rendering, digital grooming, and meshing. There are, however, a variety of discrete representations of tangent vector fields on triangle meshes, and each approach offers different tr...

  14. Unstructured Mesh Movement and Viscous Mesh Generation for CFD-Based Design Optimization Project

    Data.gov (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)...

  15. Mesh geometry impact on Micromegas performance with an Exchangeable Mesh prototype

    Energy Technology Data Exchange (ETDEWEB)

    Kuger, F., E-mail: fabian.kuger@cern.ch [CERN, Geneva (Switzerland); Julius-Maximilians-Universität, Würzburg (Germany); Bianco, M.; Iengo, P. [CERN, Geneva (Switzerland); Sekhniaidze, G. [CERN, Geneva (Switzerland); Universita e INFN, Napoli (Italy); Veenhof, R. [Uludağ University, Bursa (Turkey); Wotschack, J. [CERN, Geneva (Switzerland)

    2016-07-11

    The reconstruction precision of gaseous detectors is limited by losses of primary electrons during signal formation. In addition to common gas related losses, like attachment, Micromegas suffer from electron absorption during its transition through the micro mesh. This study aims for a deepened understanding of electron losses and their dependency on the mesh geometry. It combines experimental results obtained with a novel designed Exchangeable Mesh Micromegas (ExMe) and advanced microscopic-tracking simulations (ANSYS and Garfield++) of electron drift and mesh transition.

  16. Robust moving mesh algorithms for hybrid stretched meshes: Application to moving boundaries problems

    Science.gov (United States)

    Landry, Jonathan; Soulaïmani, Azzeddine; Luke, Edward; Ben Haj Ali, Amine

    2016-12-01

    A robust Mesh-Mover Algorithm (MMA) approach is designed to adapt meshes of moving boundaries problems. A new methodology is developed from the best combination of well-known algorithms in order to preserve the quality of initial meshes. In most situations, MMAs distribute mesh deformation while preserving a good mesh quality. However, invalid meshes are generated when the motion is complex and/or involves multiple bodies. After studying a few MMA limitations, we propose the following approach: use the Inverse Distance Weighting (IDW) function to produce the displacement field, then apply the Geometric Element Transformation Method (GETMe) smoothing algorithms to improve the resulting mesh quality, and use an untangler to revert negative elements. The proposed approach has been proven efficient to adapt meshes for various realistic aerodynamic motions: a symmetric wing that has suffered large tip bending and twisting and the high-lift components of a swept wing that has moved to different flight stages. Finally, the fluid flow problem has been solved on meshes that have moved and they have produced results close to experimental ones. However, for situations where moving boundaries are too close to each other, more improvements need to be made or other approaches should be taken, such as an overset grid method.

  17. TVD differencing on three-dimensional unstructured meshes with monotonicity-preserving correction of mesh skewness

    Science.gov (United States)

    Denner, Fabian; van Wachem, Berend G. M.

    2015-10-01

    Total variation diminishing (TVD) schemes are a widely applied group of monotonicity-preserving advection differencing schemes for partial differential equations in numerical heat transfer and computational fluid dynamics. These schemes are typically designed for one-dimensional problems or multidimensional problems on structured equidistant quadrilateral meshes. Practical applications, however, often involve complex geometries that cannot be represented by Cartesian meshes and, therefore, necessitate the application of unstructured meshes, which require a more sophisticated discretisation to account for their additional topological complexity. In principle, TVD schemes are applicable to unstructured meshes, however, not all the data required for TVD differencing is readily available on unstructured meshes, and the solution suffers from considerable numerical diffusion as a result of mesh skewness. In this article we analyse TVD differencing on unstructured three-dimensional meshes, focusing on the non-linearity of TVD differencing and the extrapolation of the virtual upwind node. Furthermore, we propose a novel monotonicity-preserving correction method for TVD schemes that significantly reduces numerical diffusion caused by mesh skewness. The presented numerical experiments demonstrate the importance of accounting for the non-linearity introduced by TVD differencing and of imposing carefully chosen limits on the extrapolated virtual upwind node, as well as the efficacy of the proposed method to correct mesh skewness.

  18. Discrete differential geometry: the nonplanar quadrilateral mesh.

    Science.gov (United States)

    Twining, Carole J; Marsland, Stephen

    2012-06-01

    We consider the problem of constructing a discrete differential geometry defined on nonplanar quadrilateral meshes. Physical models on discrete nonflat spaces are of inherent interest, as well as being used in applications such as computation for electromagnetism, fluid mechanics, and image analysis. However, the majority of analysis has focused on triangulated meshes. We consider two approaches: discretizing the tensor calculus, and a discrete mesh version of differential forms. While these two approaches are equivalent in the continuum, we show that this is not true in the discrete case. Nevertheless, we show that it is possible to construct mesh versions of the Levi-Civita connection (and hence the tensorial covariant derivative and the associated covariant exterior derivative), the torsion, and the curvature. We show how discrete analogs of the usual vector integral theorems are constructed in such a way that the appropriate conservation laws hold exactly on the mesh, rather than only as approximations to the continuum limit. We demonstrate the success of our method by constructing a mesh version of classical electromagnetism and discuss how our formalism could be used to deal with other physical models, such as fluids.

  19. Hybrid Surface Mesh Adaptation for Climate Modeling

    Institute of Scientific and Technical Information of China (English)

    Ahmed Khamayseh; Valmor de Almeida; Glen Hansen

    2008-01-01

    Solution-driven mesh adaptation is becoming quite popular for spatial error control in the numerical simulation of complex computational physics applications, such as climate modeling. Typically, spatial adaptation is achieved by element subdivision (h adaptation) with a primary goal of resolving the local length scales of interest. A second, lesspopular method of spatial adaptivity is called "mesh motion" (r adaptation); the smooth repositioning of mesh node points aimed at resizing existing elements to capture the local length scales. This paper proposes an adaptation method based on a combination of both element subdivision and node point repositioning (rh adaptation). By combining these two methods using the notion of a mobility function, the proposed approach seeks to increase the flexibility and extensibility of mesh motion algorithms while providing a somewhat smoother transition between refined regions than is pro-duced by element subdivision alone. Further, in an attempt to support the requirements of a very general class of climate simulation applications, the proposed method is de-signed to accommodate unstructured, polygonal mesh topologies in addition to the most popular mesh types.

  20. Automatic Scheme Selection for Toolkit Hex Meshing

    Energy Technology Data Exchange (ETDEWEB)

    TAUTGES,TIMOTHY J.; WHITE,DAVID R.

    1999-09-27

    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.

  1. Hydrodynamic simulations on a moving Voronoi mesh

    CERN Document Server

    Springel, Volker

    2011-01-01

    At the heart of any method for computational fluid dynamics lies the question of how the simulated fluid should be discretized. Traditionally, a fixed Eulerian mesh is often employed for this purpose, which in modern schemes may also be adaptively refined during a calculation. Particle-based methods on the other hand discretize the mass instead of the volume, yielding an approximately Lagrangian approach. It is also possible to achieve Lagrangian behavior in mesh-based methods if the mesh is allowed to move with the flow. However, such approaches have often been fraught with substantial problems related to the development of irregularity in the mesh topology. Here we describe a novel scheme that eliminates these weaknesses. It is based on a moving unstructured mesh defined by the Voronoi tessellation of a set of discrete points. The mesh is used to solve the hyperbolic conservation laws of ideal hydrodynamics with a finite volume approach, based on a second-order Godunov scheme with an exact Riemann solver. A...

  2. Meshed acellular dermal matrix:technique and application in implant based breast reconstruction

    Institute of Scientific and Technical Information of China (English)

    Dino Zammit; Jonathan Kanevsky; Fan-Yi Meng; Tassos Dionisopoulos

    2016-01-01

    Alloderm was the first acellular dermal matrix used and remains a popular choice among plastic surgeons. However, while the overall surgical outcome of breast reconstruction using alloderm has been a success, the economic burden on the health care system makes it a subject of frequent re-evaluations in cost-effectiveness. Prompted by the high price of $3,700 USD for a 6 cm × 16 cm area, our group proposes the meshing of AlloDerm to decrease the total amount needed for breast reconstruction, while achieving comparable surgical outcomes as using unmeshed alloderm.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...

  4. Reconstrucción craneofacial compleja: malla de titanio, hueso autólogo preservado en óxido de etileno y reconstrucciones tridimensionales en polimetilmetacrilato (HTR-PMI Complex craneofacial reconstruction: titanium mesh, autologous bone preserved in ethylene oxide and tridimensional polimetilmetacrilate implants (HTR-PMI

    Directory of Open Access Journals (Sweden)

    G. Flores-Lima

    2010-03-01

    more complex and esthetically rewarding procedures to patients have suffered extensive bone loss in the craniofacial area. We report our initial experience using these techniques with a retrospective analysis of 21 patients operated from January 2007 to March 2009 by a multidisciplinary team in the Hospital Militar, Centro Panamericano de Ojos and Hospital de Diagnóstico of El Salvador, who required complex craneofacial reconstruction using one or more techniques to cover the defects. The reconstructed areas have been cranium, orbital roof and floor as well as cigomatic region, anterior cranium fossa and superior maxillary sinuous. No infections or retrieval of material for reconstruction or fistulas were reported and only one post-traumatic ulcer that resolved in a conservative way. The esthetic results in the patients operated have been considered acceptable, to excellent. As a conclusions, multidisciplinary team, combination of surgical techniques and the acquisition of advanced prosthesis material for craniofacial reconstructions has resulted in a significant advance from the functional and aesthetic point of view in areas that involve this anatomically complex area.

  5. Titanium dioxide nanotube films

    Energy Technology Data Exchange (ETDEWEB)

    Roman, Ioan, E-mail: roman@metav-cd.ro [S.C. METAV-Research and Development S.R.L., Bucharest, 31C. A. Rosetti, 020011 (Romania); Trusca, Roxana Doina; Soare, Maria-Laura [S.C. METAV-Research and Development S.R.L., Bucharest, 31C. A. Rosetti, 020011 (Romania); Fratila, Corneliu [Research and Development National Institute for Nonferrous and Rare Metals, Pantelimon, 102 Biruintei, 077145 (Romania); Krasicka-Cydzik, Elzbieta [University of Zielona Gora, Department of Biomedical Engineering Division, 9 Licealna, 65-417 (Poland); Stan, Miruna-Silvia; Dinischiotu, Anca [University of Bucharest, Department of Biochemistry and Molecular Biology, 36-46 Mihail Kogalniceanu, 050107 (Romania)

    2014-04-01

    Titania nanotubes (TNTs) were prepared by anodization on different substrates (titanium, Ti6Al4V and Ti6Al7Nb alloys) in ethylene glycol and glycerol. The influence of the applied potential and processing time on the nanotube diameter and length is analyzed. The as-formed nanotube layers are amorphous but they become crystalline when subjected to subsequent thermal treatment in air at 550 °C; TNT layers grown on titanium and Ti6Al4V alloy substrates consist of anatase and rutile, while those grown on Ti6Al7Nb alloy consist only of anatase. The nanotube layers grown on Ti6Al7Nb alloy are less homogeneous, with supplementary islands of smaller diameter nanotubes, spread across the surface. Better adhesion and proliferation of osteoblasts was found for the nanotubes grown on all three substrates by comparison to an unprocessed titanium plate. The sensitivity towards bovine alkaline phosphatase was investigated mainly by electrochemical impedance spectroscopy in relation to the crystallinity, the diameter and the nature of the anodization electrolyte of the TNT/Ti samples. The measuring capacity of the annealed nanotubes of 50 nm diameter grown in glycerol was demonstrated and the corresponding calibration curve was built for the concentration range of 0.005–0.1 mg/mL. - Highlights: • Titania nanotubes (TNTs) on Ti, Ti6Al4V and Ti6Al7Nb substrates were prepared. • Quantitative dependences of anodization conditions on TNT features were established. • Morphology and electrochemical tests revealed inhomogeneity of TNT/Ti6Al7Nb films. • Particular characteristics of TNT films induce electrochemical sensitivity to ALP. • Annealed TNT/Ti impedimetric sensitivity towards ALP was demonstrated and quantified.

  6. Titanium in 1980

    Science.gov (United States)

    Minkler, Ward W.

    1981-04-01

    Much attention is being focused on the availability and use of non-fuel minerals in the United States. Because of the rapid increase in demand since 1978, titanium has been one of the much-publicized metals in this group. Sponge producers are now expanding sponge manufacturing plants to meet this greater demand, and it now appears that there could be a surplus of sponge in 1981. A delay in airplane purchases caused by severe operating losses of the airlines could have a significant effect on mill product shipments in 1981. However, there is no reason to believe that titanium has reached maturity as a structural aerospace or industrial metal. While it is unreasonable to anticipate that demand will continue to grow at the same rate experienced between 1978 and 1980, new greenfield capacity will nevertheless be required in the early 1980s. Two basic issues must be resolved before such ventures become reality: 1) choice of process; and 2) method for financing, either public or private. Both will be the subject of study and debate in 1981.

  7. Compaction of Titanium Powders

    Energy Technology Data Exchange (ETDEWEB)

    Gerdemann, Stephen,J; Jablonski, Paul, J

    2011-05-01

    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines<150 {micro}m,<75 {micro}m, and<45 {micro}m; two different sizes of a hydride-dehydride [HDH]<75 {micro}m and<45 {micro}m; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  8. Multiple Staggered Mesh Ewald: Boosting the Accuracy of the Smooth Particle Mesh Ewald Method

    CERN Document Server

    Wang, Han; Fang, Jun

    2016-01-01

    The smooth particle mesh Ewald (SPME) method is the standard method for computing the electrostatic interactions in the molecular simulations. In this work, the multiple staggered mesh Ewald (MSME) method is proposed to boost the accuracy of the SPME method. Unlike the SPME that achieves higher accuracy by refining the mesh, the MSME improves the accuracy by averaging the standard SPME forces computed on, e.g. $M$, staggered meshes. We prove, from theoretical perspective, that the MSME is as accurate as the SPME, but uses $M^2$ times less mesh points in a certain parameter range. In the complementary parameter range, the MSME is as accurate as the SPME with twice of the interpolation order. The theoretical conclusions are numerically validated both by a uniform and uncorrelated charge system, and by a three-point-charge water system that is widely used as solvent for the bio-macromolecules.

  9. Conservative interpolation between general spherical meshes

    Directory of Open Access Journals (Sweden)

    E. Kritsikis

    2015-06-01

    Full Text Available An efficient, local, explicit, second-order, conservative interpolation algorithm between spherical meshes is presented. The cells composing the source and target meshes may be either spherical polygons or longitude–latitude quadrilaterals. Second-order accuracy is obtained by piecewise-linear finite volume reconstruction over the source mesh. Global conservation is achieved through the introduction of a supermesh, whose cells are all possible intersections of source and target cells. Areas and intersections are computed exactly to yield a geometrically exact method. The main efficiency bottleneck caused by the construction of the supermesh is overcome by adopting tree-based data structures and algorithms, from which the mesh connectivity can also be deduced efficiently. The theoretical second-order accuracy is verified using a smooth test function and pairs of meshes commonly used for atmospheric modelling. Experiments confirm that the most expensive operations, especially the supermesh construction, have O(NlogN computational cost. The method presented is meant to be incorporated in pre- or post-processing atmospheric modelling pipelines, or directly into models for flexible input/output. It could also serve as a basis for conservative coupling between model components, e.g. atmosphere and ocean.

  10. Conservative interpolation between general spherical meshes

    Science.gov (United States)

    Kritsikis, Evaggelos; Aechtner, Matthias; Meurdesoif, Yann; Dubos, Thomas

    2017-01-01

    An efficient, local, explicit, second-order, conservative interpolation algorithm between spherical meshes is presented. The cells composing the source and target meshes may be either spherical polygons or latitude-longitude quadrilaterals. Second-order accuracy is obtained by piece-wise linear finite-volume reconstruction over the source mesh. Global conservation is achieved through the introduction of a supermesh, whose cells are all possible intersections of source and target cells. Areas and intersections are computed exactly to yield a geometrically exact method. The main efficiency bottleneck caused by the construction of the supermesh is overcome by adopting tree-based data structures and algorithms, from which the mesh connectivity can also be deduced efficiently.The theoretical second-order accuracy is verified using a smooth test function and pairs of meshes commonly used for atmospheric modelling. Experiments confirm that the most expensive operations, especially the supermesh construction, have O(NlogN) computational cost. The method presented is meant to be incorporated in pre- or post-processing atmospheric modelling pipelines, or directly into models for flexible input/output. It could also serve as a basis for conservative coupling between model components, e.g., atmosphere and ocean.

  11. Development and mechanical characterization of porous titanium bone substitutes.

    Science.gov (United States)

    Barbas, A; Bonnet, A-S; Lipinski, P; Pesci, R; Dubois, G

    2012-05-01

    Commercially Pure Porous Titanium (CPPTi) can be used for surgical implants to avoid the stress shielding effect due to the mismatch between the mechanical properties of titanium and bone. Most researchers in this area deal with randomly distributed pores or simple architectures in titanium alloys. The control of porosity, pore size and distribution is necessary to obtain implants with mechanical properties close to those of bone and to ensure their osseointegration. The aim of the present work was therefore to develop and characterize such a specific porous structure. First of all, the properties of titanium made by Selective Laser Melting (SLM) were characterized through experimental testing on bulk specimens. An elementary pattern of the porous structure was then designed to mimic the orthotropic properties of the human bone following several mechanical and geometrical criteria. Finite Element Analysis (FEA) was used to optimize the pattern. A porosity of 53% and pore sizes in the range of 860 to 1500 μm were finally adopted. Tensile tests on porous samples were then carried out to validate the properties obtained numerically and identify the failure modes of the samples. Finally, FE elastoplastic analyses were performed on the porous samples in order to propose a failure criterion for the design of porous substitutes.

  12. The Sustainable Improvement of Manufacturing for Nano-Titanium

    Directory of Open Access Journals (Sweden)

    Chia-Nan Wang

    2016-04-01

    Full Text Available Scientists have found that nanomaterials possess many outstanding features in their tiny grain structure compared to other common materials. Titanium at the nano-grain scale shows many novel characteristics which demonstrate suitability for use in surgical implants. In general, equal channel angular pressing (ECAP is the most popular and simple process to produce nano-titanium. However, ECAP is time-consuming, power-wasting, and insufficiently produces the ultrafine grain structure. Therefore, the objective of this research is to propose a new method to improve the ECAP’s performances to reach the ultrafine grain structure, and also to save production costs, based on the innovation theory of Teoriya Resheniya Izobreatatelskih Zadatch (TRIZ. Research results show that the process time is reduced by 80%, and 94% of the energy is saved. Moreover, the grain size of the diameter for nano-titanium can be reduced from 160 nanometers (nm to 80 nm. The results are a 50% reduction of diameter and a 75% improvement of volume. At the same time, the method creates a refined grain size and good mechanical properties in the nano-titanium. The proposed method can be applied to produce any nanomaterial as well as biomaterials.

  13. Characterization of cellular titanium for biomedical applications

    Science.gov (United States)

    Hrabe, Nikolas Wilson

    By controlling structural features (relative density, pore size, strut size) of cellular titanium (also known as porous titanium), the mechanical properties can be optimized to reduce the effects of stress shielding currently observed in load-bearing bone replacement implants. Thermal gravimetric analysis of a sacrificial scaffold system lead to important processing modifications in an attempt to meet chemistry requirements for surgical grade titanium not met in previous work. Despite these modifications chemistry did not meet requirements for carbon, nitrogen, or oxygen. Commercially pure titanium (CPTi) porous structures were made over a range of relative densities using laser engineered net shaping (LENS). From monotonic compression tests, yield strength and elastic modulus in the range of bone were achieved but did not scale with relative density as predicted by the Gibson-Ashby analytical model. Compression-compression fatigue resistance was high, as no failures were observed for test stresses up to 133% yield strength, which is thought to be influenced by the dense exterior shell of the samples. Structures were also fabricated over a range of relative densities using selective electron beam melting (SEBM or EBM), and structural, mechanical, and in-vitro properties were measured for three materials (as-built Ti-6A1-4V, Ti-6A1-4V after hot isostatic pressing (HIPing), and as-built CPTi). For structures of all three materials, yield strength and elastic modulus was within the range for bone. Numerical modeling results suggested cell shape and sintered particles on strut surfaces affect the scaling of elastic modulus with relative density and lead to the observed difference from the Gibson-Ashby model. Normalized fatigue strengths at 106 cycles ranged from 0.150.25 for as-built Ti-6A1-4V structures, which is lower than expected. Results for HIPed Ti-6A1-4V structures and CPTi structures suggest that stress concentrations from closed porosity within struts as well

  14. Purification and utilization of titanium

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Wonbaek; Yu, Hyosin; Chung, Inwha; Rhee, Kang In; Choi, Good Sun; Lee, Chulkyung; Youn, In Ju; Chung, Jinki; Suh, Chang Youl; Yang, Dong Hyo [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1997-12-01

    Current domestic market appears not to be sufficient enough for the large scale investment for the expensive vacuum-melting equipment. Besides, related ingot-processing technologies like rolling, extrusion, and forging of titanium should be prepared in advance. In the mean time, the attempt to recycle expensive titanium scraps produced in our nation would be worthwhile in view of the reduction of import from foreign countries and of saving valuable secondary resources. The objectives for this research is to develop technology for the production of high purity titanium metals from sponges and scraps and to extend the developed technology to industrial applications. PREP(Plasma-Rotating-Electrode Process) and HDP(Hydride-Dehydride Process) were adopted to evaluate the possibility of using domestic titanium scraps in the production of pure titanium powders. Those scraps were titanium pipes of Grade 2 and various sputtering targets having a purity of 99.995%. The titanium powders produced by both methods were examined and compared with conventionally prepared ones. Their shape, size distribution, structure and above of all major impurities were determine to evaluate these process. The powders produced by PREP were of round shape having narrow size distribution at about 200 micron. Meanwhile, HDP powders were irregular shaped having a much wider size distribution. Both metallic and non-metallic impurities were lower in PREP powders due to the unavoidable contamination during crushing processes in HDP. Thus, PREP has advantages towards purity and uniformity while HDP toward finer sizes. Apparently, for the production of high purity titanium powders by HDP, special considerations should be made to prevent contamination during various steps in the process. In PREP powders, smaller particles contained more oxygen since they have larger surface/volume ratio. The tendency was also observed in the hardness measurement revealing the strengthening effect of oxygen in pure

  15. Connectivity editing for quad-dominant meshes

    KAUST Repository

    Peng, Chihan

    2013-08-01

    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.

  16. GRChombo: Numerical relativity with adaptive mesh refinement

    Science.gov (United States)

    Clough, Katy; Figueras, Pau; Finkel, Hal; Kunesch, Markus; Lim, Eugene A.; Tunyasuvunakool, Saran

    2015-12-01

    In this work, we introduce {\\mathtt{GRChombo}}: a new numerical relativity code which incorporates full adaptive mesh refinement (AMR) using block structured Berger-Rigoutsos grid generation. The code supports non-trivial ‘many-boxes-in-many-boxes’ mesh hierarchies and massive parallelism through the message passing interface. {\\mathtt{GRChombo}} evolves the Einstein equation using the standard BSSN formalism, with an option to turn on CCZ4 constraint damping if required. The AMR capability permits the study of a range of new physics which has previously been computationally infeasible in a full 3 + 1 setting, while also significantly simplifying the process of setting up the mesh for these problems. We show that {\\mathtt{GRChombo}} can stably and accurately evolve standard spacetimes such as binary black hole mergers and scalar collapses into black holes, demonstrate the performance characteristics of our code, and discuss various physics problems which stand to benefit from the AMR technique.

  17. Retrofitting Masonry Walls with Carbon Mesh

    Directory of Open Access Journals (Sweden)

    Patrick Bischof

    2014-01-01

    Full Text Available Static-cyclic shear load tests and tensile tests on retrofitted masonry walls were conducted at UAS Fribourg for an evaluation of the newly developed retrofitting system, the S&P ARMO-System. This retrofitting system consists of a composite of carbon mesh embedded in a specially adapted high quality spray mortar. It can be applied with established construction techniques using traditional construction materials. The experimental study has shown that masonry walls reinforced by this retrofitting system reach a similar strength and a higher ductility than retrofits by means of bonded carbon fiber reinforced polymer sheets. Hence, the retrofitting system using carbon fiber meshes embedded in a high quality mortar constitutes a good option for static or seismic retrofits or reinforcements for masonry walls. However, the experimental studies also revealed that the mechanical anchorage of carbon mesh may be delicate depending on its design.

  18. NASA Lewis Meshed VSAT Workshop meeting summary

    Science.gov (United States)

    Ivancic, William

    1993-11-01

    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.

  19. Mesh saliency with adaptive local patches

    Science.gov (United States)

    Nouri, Anass; Charrier, Christophe; Lézoray, Olivier

    2015-03-01

    3D object shapes (represented by meshes) include both areas that attract the visual attention of human observers and others less or not attractive at all. This visual attention depends on the degree of saliency exposed by these areas. In this paper, we propose a technique for detecting salient regions in meshes. To do so, we define a local surface descriptor based on local patches of adaptive size and filled with a local height field. The saliency of mesh vertices is then defined as its degree measure with edges weights computed from adaptive patch similarities. Our approach is compared to the state-of-the-art and presents competitive results. A study evaluating the influence of the parameters establishing this approach is also carried out. The strength and the stability of our approach with respect to noise and simplification are also studied.

  20. Performance of a streaming mesh refinement algorithm.

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, David C.; Pebay, Philippe Pierre

    2004-08-01

    In SAND report 2004-1617, we outline a method for edge-based tetrahedral subdivision that does not rely on saving state or communication to produce compatible tetrahedralizations. This report analyzes the performance of the technique by characterizing (a) mesh quality, (b) execution time, and (c) traits of the algorithm that could affect quality or execution time differently for different meshes. It also details the method used to debug the several hundred subdivision templates that the algorithm relies upon. Mesh quality is on par with other similar refinement schemes and throughput on modern hardware can exceed 600,000 output tetrahedra per second. But if you want to understand the traits of the algorithm, you have to read the report!

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

    Energy Technology Data Exchange (ETDEWEB)

    TAUTGES,TIMOTHY J.

    2000-02-14

    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.

  2. Antimicrobial titanium/silver PVD coatings on titanium

    OpenAIRE

    Thull Roger; Glückermann Susanne K; Ewald Andrea; Gbureck Uwe

    2006-01-01

    Abstract Background Biofilm formation and deep infection of endoprostheses is a recurrent complication in implant surgery. Post-operative infections may be overcome by adjusting antimicrobial properties of the implant surface prior to implantation. In this work we described the development of an antimicrobial titanium/silver hard coating via the physical vapor deposition (PVD) process. Methods Coatings with a thickness of approximately 2 μm were deposited on titanium surfaces by simultaneous ...

  3. Adaptive mesh refinement for storm surge

    KAUST Repository

    Mandli, Kyle T.

    2014-03-01

    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.

  4. Relativistic MHD with Adaptive Mesh Refinement

    CERN Document Server

    Anderson, M; Liebling, S L; Neilsen, D; Anderson, Matthew; Hirschmann, Eric; Liebling, Steven L.; Neilsen, David

    2006-01-01

    We solve the relativistic magnetohydrodynamics (MHD) equations using a finite difference Convex ENO method (CENO) in 3+1 dimensions within a distributed parallel adaptive mesh refinement (AMR) infrastructure. In flat space we examine a Balsara blast wave problem along with a spherical blast wave and a relativistic rotor test both with unigrid and AMR simulations. The AMR simulations substantially improve performance while reproducing the resolution equivalent unigrid simulation results. We also investigate the impact of hyperbolic divergence cleaning for the spherical blast wave and relativistic rotor. We include unigrid and mesh refinement parallel performance measurements for the spherical blast wave.

  5. Laparoscopic rectocele repair using polyglactin mesh.

    Science.gov (United States)

    Lyons, T L; Winer, W K

    1997-05-01

    We assessed the efficacy of laparoscopic treatment of rectocele defect using a polyglactin mesh graft. From May 1, 1995, through September 30, 1995, we prospectively evaluated 20 women (age 38-74 yrs) undergoing pelvic floor reconstruction for symptomatic pelvic floor prolapse, with or without hysterectomy. Morbidity of the procedure was extremely low compared with standard transvaginal and transrectal approaches. Patients were followed at 3-month intervals for 1 year. Sixteen had resolution of symptoms. Laparoscopic application of polyglactin mesh for the repair of the rectocele defect is a viable option, although long-term follow-up is necessary.

  6. Adaptive Mesh Refinement for Storm Surge

    CERN Document Server

    Mandli, Kyle T

    2014-01-01

    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.

  7. First human use of hybrid synthetic/biologic mesh in ventral hernia repair: a multicenter trial.

    Science.gov (United States)

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

    2017-07-19

    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

  8. Advanced titanium processing

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, Alan D.; Gerdemann, Stephen J.; Schrems, Karol K.; Holcomb, Gordon R.; Argetsinger, Edward R.; Hansen, Jeffrey S.; Paige, Jack I.; Turner, Paul C.

    2001-01-01

    The Albany Research Center of the U.S. Department of Energy has been investigating a means to form useful wrought products by direct and continuous casting of titanium bars using cold-wall induction melting rather than current batch practices such as vacuum arc remelting. Continuous ingots produced by cold-wall induction melting, utilizing a bottomless water-cooled copper crucible, without slag (CaF2) additions had minor defects in the surface such as ''hot tears''. Slag additions as low as 0.5 weight percent were used to improve the surface finish. Therefore, a slag melted experimental Ti-6Al-4V alloy ingot was compared to a commercial Ti-6Al-4V alloy ingot in the areas of physical, chemical, mechanical, and corrosion attributes to address the question, ''Are any detrimental effects caused by slag addition''?

  9. Hemocompatibility of titanium nitride.

    Science.gov (United States)

    Dion, I; Baquey, C; Candelon, B; Monties, J R

    1992-10-01

    The left ventricular assist device is based on the principle of the Maillard-Wenkel rotative pump. The materials which make up the pump must present particular mechanical, tribological, thermal and chemical properties. Titanium nitride (TiN) because of its surface properties and graphite because of its bulk characteristics have been chosen. The present study evaluated the in vitro hemocompatibility of TiN coating deposited by the chemical vapor deposition process. Protein adsorption, platelet retention and hemolysis tests have been carried out. In spite of some disparities, the TiN behavior towards albumin and fibrinogen is interesting, compared with the one of a reference medical grade elastomer. The platelet retention test gives similar results as those achieved with the same elastomer. The hemolysis percentage is near to zero. TiN shows interesting characteristics, as far as mechanical and tribological problems are concerned, and presents very encouraging blood tolerability properties.

  10. Short-term results for laparoscopic repair of large paraesophageal hiatal hernias with Gore Bio A® mesh.

    Science.gov (United States)

    Priego Jiménez, Pablo; Salvador Sanchís, José Luis; Angel, Vicente; Escrig-Sos, Javier

    2014-01-01

    The application of mesh-reinforced hiatal closure has resulted in a significant reduction in recurrence rates in comparison with primary suture repair. One of the most debated issues is the risk of complications related to the use of the prosthesis, such as esophageal erosion and postoperative dysphagia. The aim of this study is to present our short-terms results in the treatment of laparoscopic paraesophageal hiatal hernia (LPHH) with a synthetic polyglycolic acid:trimethylene carbonate mesh (Gore Bio A(®)). From January 2011 to December 2012, 10 patients with large paraesophageal hiatal hernias and hiatal defect over 5 cm were included. Primary simple suture of the crura and additional reinforcement with a Gore Bio A(®) mesh was performed. Hiatal hernia or gastroesophageal reflux disease (GERD) symptoms recurrence, dysphagia and mesh-related complications were investigated. Of the 10 patients undergoing mesh repair, there were 7 women and 3 men with a mean age of 65.5 years. All operations were completed laparoscopically. Median postoperative stay was 3 days. After a median follow-up of 20.3 months, one patient developed a recurrent hiatal hernia (10%). There were no mesh-related complications. The use of Gore Bio A(®) mesh for the laparoscopic repair of large paraesophageal hiatal hernias is safe and with a reasonably low recurrence rate in this short-term study. Additional long-term studies with ample numbers carried out for years will be necessary to see if this synthetic mesh is not only safe but also successful in the prevention of recurrences. Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  11. Lumbar hernia treated with lightweight partially absorbable mesh: report of a case.

    Science.gov (United States)

    Yamaguchi, Shohei; Tsutsumi, Norifumi; Kusumoto, Eiji; Endo, Kazuya; Ikejiri, Koji; Yamashita, Yo-ichi; Uchiyama, Hideaki; Saeki, Hiroshi; Oki, Eiji; Kawanaka, Hirofumi; Morita, Masaru; Ikeda, Tetsuo; Maehara, Yoshihiko

    2013-12-01

    Superior lumbar hernia, also known as Grynfeltt-Lesshaft hernia, is an uncommon abdominal wall defect. We report a case of superior lumbar hernia, which was successfully treated with a lightweight partially absorbable mesh. A 73-year-old man visited our department with complaints of lumbar pain and a feeling of pressure associated with a right lumbar mass. A CT scan of the abdomen demonstrated a defect in the aponeurosis of the transversus abdominis muscle and a protrusion of the small intestine through the defect. The diagnosis of a right superior lumbar hernia was made. The lumbar hernia was surgically treated with a lightweight large-pore polypropylene mesh containing an absorbable component consisting of poliglecaprone (ULTRAPRO Plug). The patient had no evidence of recurrence after 4 years of follow-up without any sense of discomfort. This is the first case report of a lumbar hernia treated with a lightweight partially absorbable mesh. This partially absorbable mesh can be considered to be suitable for the treatment of a lumbar hernia.

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

    Directory of Open Access Journals (Sweden)

    Almoutaz A Eltayeb

    2013-01-01

    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.

  13. MeshEZW: an image coder using mesh and finite elements

    Science.gov (United States)

    Landais, Thomas; Bonnaud, Laurent; Chassery, Jean-Marc

    2003-08-01

    In this paper, we present a new method to compress the information in an image, called MeshEZW. The proposed approach is based on the finite elements method, a mesh construction and a zerotree method. The zerotree method is an adaptive of the EZW algorithm with two new symbols for increasing the performance. These steps allow a progressive representation of the image by the automatic construction of a bitstream. The mesh structure is adapted to the image compression domain and is defined to allow video comrpession. The coder is described and some preliminary results are discussed.

  14. Electrochemical process of titanium extraction

    Institute of Scientific and Technical Information of China (English)

    CH. RVS. NAGESH; C. S. RAMACHANDRAN

    2007-01-01

    A wide variety of processes are being pursued by researchers for cost effective extraction of titanium metal. Electrochemical processes are promising due to simplicity and being less capital intensive. Some of the promising electrochemical processes of titanium extraction were reviewed and the results of laboratory scale experiments on electrochemical reduction of TiO2 granules were brought out. Some of the kinetic parameters of the reduction process were discussed while presenting the quality improvements achieved in the experimentation.

  15. Low cost titanium--myth or reality

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Paul C.; Hartman, Alan D.; Hansen, Jeffrey S.; Gerdemann, Stephen J.

    2001-01-01

    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium, and titanium cost has prevented its use in non-aerospace applications including the automotive and heavy vehicle industries.

  16. Titanium in the geothermal industry

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, R. [TIMET UK Ltd., Swansea (United Kingdom)

    2003-12-01

    Titanium resists seawater and brine at temperatures as high as 260{sup o}C, and is also resistant to corrosion by sulphur dioxide; hydrogen sulphide; and aqueous solutions of those gases. Titanium is fully resistant to corrosion and stress corrosion cracking in the standard NACE test solution containing 3000 ppm dissolved H{sub 2}S, 5% NACl, and 0.5% acetic acid (pH 3.5). To avoid pitting at temperatures above 80{sup o}C, titanium alloys containing nickel, molybdenum, palladium or ruthenium are used. Examples of equipment fabricated in titanium in order to withstand the corrosive fluids present in some geothermal installations are plate heat exchangers and well casing. By careful selection of the grade of titanium, material thickness (with no corrosion allowance) and fabrication method, an economic fabrication with low maintenance costs and high availability can be achieved. A prime example of the application of titanium in the geothermal industry is the use of Grade 29 well casing in the Salton Sea, USA, which enables the exploitation of a geothermal resource containing highly corrosive brine. Advances in production technology are being applied to reduce the cost of the casing pipe. This technology may enable the use of sea water injection to augment weak or depleted aquifers, or to generate steam from Hot Dry Rocks. (author)

  17. Constrained and joint inversion on unstructured meshes

    Science.gov (United States)

    Doetsch, J.; Jordi, C.; Rieckh, V.; Guenther, T.; Schmelzbach, C.

    2015-12-01

    Unstructured meshes allow for inclusion of arbitrary surface topography, complex acquisition geometry and undulating geological interfaces in the inversion of geophysical data. This flexibility opens new opportunities for coupling different geophysical and hydrological data sets in constrained and joint inversions. For example, incorporating geological interfaces that have been derived from high-resolution geophysical data (e.g., ground penetrating radar) can add geological constraints to inversions of electrical resistivity data. These constraints can be critical for a hydrogeological interpretation of the inversion results. For time-lapse inversions of geophysical data, constraints can be derived from hydrological point measurements in boreholes, but it is difficult to include these hard constraints in the inversion of electrical resistivity monitoring data. Especially mesh density and the regularization footprint around the hydrological point measurements are important for an improved inversion compared to the unconstrained case. With the help of synthetic and field examples, we analyze how regularization and coupling operators should be chosen for time-lapse inversions constrained by point measurements and for joint inversions of geophysical data in order to take full advantage of the flexibility of unstructured meshes. For the case of constraining to point measurements, it is important to choose a regularization operator that extends beyond the neighboring cells and the uncertainty in the point measurements needs to be accounted for. For joint inversion, the choice of the regularization depends on the expected subsurface heterogeneity and the cell size of the parameter mesh.

  18. Hash functions and triangular mesh reconstruction*1

    Science.gov (United States)

    Hrádek, Jan; Kuchař, Martin; Skala, Václav

    2003-07-01

    Some applications use data formats (e.g. STL file format), where a set of triangles is used to represent the surface of a 3D object and it is necessary to reconstruct the triangular mesh with adjacency information. It is a lengthy process for large data sets as the time complexity of this process is O( N log N), where N is number of triangles. Triangular mesh reconstruction is a general problem and relevant algorithms can be used in GIS and DTM systems as well as in CAD/CAM systems. Many algorithms rely on space subdivision techniques while hash functions offer a more effective solution to the reconstruction problem. Hash data structures are widely used throughout the field of computer science. The hash table can be used to speed up the process of triangular mesh reconstruction but the speed strongly depends on hash function properties. Nevertheless the design or selection of the hash function for data sets with unknown properties is a serious problem. This paper describes a new hash function, presents the properties obtained for large data sets, and discusses validity of the reconstructed surface. Experimental results proved theoretical considerations and advantages of hash function use for mesh reconstruction.

  19. Particle Collection Efficiency for Nylon Mesh Screens.

    Science.gov (United States)

    Cena, Lorenzo G; Ku, Bon-Ki; Peters, Thomas M

    Mesh screens composed of nylon fibers leave minimal residual ash and produce no significant spectral interference when ashed for spectrometric examination. These characteristics make nylon mesh screens attractive as a collection substrate for nanoparticles. A theoretical single-fiber efficiency expression developed for wire-mesh screens was evaluated for estimating the collection efficiency of submicrometer particles for nylon mesh screens. Pressure drop across the screens, the effect of particle morphology (spherical and highly fractal) on collection efficiency and single-fiber efficiency were evaluated experimentally for three pore sizes (60, 100 and 180 μm) at three flow rates (2.5, 4 and 6 Lpm). The pressure drop across the screens was found to increase linearly with superficial velocity. The collection efficiency of the screens was found to vary by less than 4% regardless of particle morphology. Single-fiber efficiency calculated from experimental data was in good agreement with that estimated from theory for particles between 40 and 150 nm but deviated from theory for particles outside this size range. New coefficients for the single-fiber efficiency model were identified that minimized the sum of square error (SSE) between the values estimated with the model and those determined experimentally. Compared to the original theory, the SSE calculated using the modified theory was at least one order of magnitude lower for all screens and flow rates with the exception of the 60-μm pore screens at 2.5 Lpm, where the decrease was threefold.

  20. Functionalized Nanofiber Meshes Enhance Immunosorbent Assays.

    Science.gov (United States)

    Hersey, Joseph S; Meller, Amit; Grinstaff, Mark W

    2015-12-01

    Three-dimensional substrates with high surface-to-volume ratios and subsequently large protein binding capacities are of interest for advanced immunosorbent assays utilizing integrated microfluidics and nanosensing elements. A library of bioactive and antifouling electrospun nanofiber substrates, which are composed of high-molecular-weight poly(oxanorbornene) derivatives, is described. Specifically, a set of copolymers are synthesized from three 7-oxanorbornene monomers to create a set of water insoluble copolymers with both biotin (bioactive) and triethylene glycol (TEG) (antifouling) functionality. Porous three-dimensional nanofiber meshes are electrospun from these copolymers with the ability to specifically bind streptavidin while minimizing the nonspecific binding of other proteins. Fluorescently labeled streptavidin is used to quantify the streptavidin binding capacity of each mesh type through confocal microscopy. A simplified enzyme-linked immunosorbent assay (ELISA) is presented to assess the protein binding capabilities and detection limits of these nanofiber meshes under both static conditions (26 h) and flow conditions (1 h) for a model target protein (i.e., mouse IgG) using a horseradish peroxidase (HRP) colorimetric assay. Bioactive and antifouling nanofiber meshes outperform traditional streptavidin-coated polystyrene plates under flow, validating their use in future advanced immunosorbent assays and their compatibility with microfluidic-based biosensors.

  1. Mesh Optimization for Ground Vehicle Aerodynamics

    Directory of Open Access Journals (Sweden)

    Adrian Gaylard

    2010-04-01

    Full Text Available

    Mesh optimization strategy for estimating accurate drag of a ground vehicle is proposed based on examining the effect of different mesh parameters.  The optimized mesh parameters were selected using design of experiment (DOE method to be able to work in a limited memory environment and in a reasonable amount of time but without compromising the accuracy of results. The study was further extended to take into account the car model size effect. Three car model sizes have been investigated and compared with MIRA scale wind tunnel results. Parameters that lead to drag value closer to experiment with less memory and computational time have been identified. Scaling the optimized mesh size with the length of car model was successfully used to predict the drag of the other car sizes with reasonable accuracy. This investigation was carried out using STARCCM+ commercial software package, however the findings can be applied to any other CFD package.

  2. Details of tetrahedral anisotropic mesh adaptation

    Science.gov (United States)

    Jensen, Kristian Ejlebjerg; Gorman, Gerard

    2016-04-01

    We have implemented tetrahedral anisotropic mesh adaptation using the local operations of coarsening, swapping, refinement and smoothing in MATLAB without the use of any for- N loops, i.e. the script is fully vectorised. In the process of doing so, we have made three observations related to details of the implementation: 1. restricting refinement to a single edge split per element not only simplifies the code, it also improves mesh quality, 2. face to edge swapping is unnecessary, and 3. optimising for the Vassilevski functional tends to give a little higher value for the mean condition number functional than optimising for the condition number functional directly. These observations have been made for a uniform and a radial shock metric field, both starting from a structured mesh in a cube. Finally, we compare two coarsening techniques and demonstrate the importance of applying smoothing in the mesh adaptation loop. The results pertain to a unit cube geometry, but we also show the effect of corners and edges by applying the implementation in a spherical geometry.

  3. Drag reduction properties of superhydrophobic mesh pipes

    Science.gov (United States)

    Geraldi, Nicasio R.; Dodd, Linzi E.; Xu, Ben B.; Wells, Gary G.; Wood, David; Newton, Michael I.; McHale, Glen

    2017-09-01

    Even with the recent extensive study into superhydrophobic surfaces, the fabrication of such surfaces on the inside walls of a pipe remains challenging. In this work we report a convenient bi-layered pipe design using a thin superhydrophobic metallic mesh formed into a tube, supported inside another pipe. A flow system was constructed to test the fabricated bi-layer pipeline, which allowed for different constant flow rates of water to be passed through the pipe, whilst the differential pressure was measured, from which the drag coefficient (ƒ) and Reynolds numbers (Re) were calculated. Expected values of ƒ were found for smooth glass pipes for the Reynolds number (Re) range 750-10 000, in both the laminar and part of the turbulent regimes. Flow through plain meshes without the superhydrophobic coating were also measured over a similar range (750  superhydrophobic coating, ƒ was found for 4000  superhydrophobic mesh can support a plastron and provide a drag reduction compared to a plain mesh, however, the plastron is progressively destroyed with use and in particular at higher flow rates.

  4. Performance Evaluation of Coded Meshed Networks

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...

  5. Mesh Currents and Josephson Junction Arrays

    OpenAIRE

    1995-01-01

    A simple but accurate mesh current analysis is performed on a XY model and on a SIMF model to derive the equations for a Josephson junction array. The equations obtained here turn out to be different from other equations already existing in the literature. Moreover, it is shown that the two models come from an unique hidden structure

  6. Treatment of Thoracolumbar Spinal Infections through Anterolateral Approaches Using Expandable Titanium Mesh Cage for Spine Reconstruction

    Directory of Open Access Journals (Sweden)

    Tarantino Roberto

    2012-01-01

    Full Text Available Pyogenic vertebral osteomyelitis (PVO is still a rare pathology. However, its incidence is on the rise. This is due to an increasing population with predisposing factors. Also, the availability of more effective diagnostic tools has brought it increasingly to the surgeon’s attention. In this study the patients were treated in the Neurosurgery Division of the Department of Neurological Sciences and Psychiatry of the Sapienza University of Rome, between 2001 and 2009. They had thoracolumbar pyogenic spondylitis. This study was undertaken in order to identify the correct diagnostic and therapeutic treatment needed in such cases. From the cases studied here, it is evident that spinal infections can be extremely insidious and that diagnosis tends to be reached late. Surgery, along with the antibiotic treatment, allows for eradication of the causes of the pathology by the reclamation of the affected region. Surgery is also fundamental in helping to recover vital functions and in restoring as much as possible the correct curvature of the rachises. The use of an anterolateral approach is dictated by the necessity of obtaining 360° stability as well as by the need to clear away extensive infections, which are not always reachable using a posterior approach.

  7. Treatment of Thoracolumbar Spinal Infections through Anterolateral Approaches Using Expandable Titanium Mesh Cage for Spine Reconstruction

    Science.gov (United States)

    Roberto, Tarantino; Daniele, Marruzzo; Martina, Cappelletti; Tiziano, De Giacomo; Roberto, Delfini

    2012-01-01

    Pyogenic vertebral osteomyelitis (PVO) is still a rare pathology. However, its incidence is on the rise. This is due to an increasing population with predisposing factors. Also, the availability of more effective diagnostic tools has brought it increasingly to the surgeon's attention. In this study the patients were treated in the Neurosurgery Division of the Department of Neurological Sciences and Psychiatry of the Sapienza University of Rome, between 2001 and 2009. They had thoracolumbar pyogenic spondylitis. This study was undertaken in order to identify the correct diagnostic and therapeutic treatment needed in such cases. From the cases studied here, it is evident that spinal infections can be extremely insidious and that diagnosis tends to be reached late. Surgery, along with the antibiotic treatment, allows for eradication of the causes of the pathology by the reclamation of the affected region. Surgery is also fundamental in helping to recover vital functions and in restoring as much as possible the correct curvature of the rachises. The use of an anterolateral approach is dictated by the necessity of obtaining 360° stability as well as by the need to clear away extensive infections, which are not always reachable using a posterior approach. PMID:23193382

  8. Oxidation and degradation of polypropylene transvaginal mesh.

    Science.gov (United States)

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

    2017-04-01

    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.

  9. Wireless Mesh Network Routing Under Uncertain Demands

    Science.gov (United States)

    Wellons, Jonathan; Dai, Liang; Chang, Bin; Xue, Yuan

    Traffic routing plays a critical role in determining the performance of a wireless mesh network. Recent research results usually fall into two ends of the spectrum. On one end are the heuristic routing algorithms, which are highly adaptive to the dynamic environments of wireless networks yet lack the analytical properties of how well the network performs globally. On the other end are the optimal routing algorithms that are derived from the optimization problem formulation of mesh network routing. They can usually claim analytical properties such as resource use optimality and throughput fairness. However, traffic demand is usually implicitly assumed as static and known a priori in these problem formulations. In contrast, recent studies of wireless network traces show that the traffic demand, even being aggregated at access points, is highly dynamic and hard to estimate. Thus, to apply the optimization-based routing solution in practice, one must take into account the dynamic and uncertain nature of wireless traffic demand. There are two basic approaches to address the traffic uncertainty in optimal mesh network routing (1) predictive routing that infers the traffic demand with maximum possibility based in its history and optimizes the routing strategy based on the predicted traffic demand and (2) oblivious routing that considers all the possible traffic demands and selects the routing strategy where the worst-case network performance could be optimized. This chapter provides an overview of the optimal routing strategies for wireless mesh networks with a focus on the above two strategies that explicitly consider the traffic uncertainty. It also identifies the key factors that affect the performance of each routing strategy and provides guidelines towards the strategy selection in mesh network routing under uncertain traffic demands.

  10. The mesh-matching algorithm: an automatic 3D mesh generator for Finite element structures

    CERN Document Server

    Couteau, B; Lavallee, S; Payan, Yohan; Lavallee, St\\'{e}phane

    2000-01-01

    Several authors have employed Finite Element Analysis (FEA) for stress and strain analysis in orthopaedic biomechanics. Unfortunately, the use of three-dimensional models is time consuming and consequently the number of analysis to be performed is limited. The authors have investigated a new method allowing automatically 3D mesh generation for structures as complex as bone for example. This method called Mesh-Matching (M-M) algorithm generated automatically customized 3D meshes of bones from an already existing model. The M-M algorithm has been used to generate FE models of ten proximal human femora from an initial one which had been experimentally validated. The new meshes seemed to demonstrate satisfying results.

  11. Randomized clinical trial of self-gripping mesh versus sutured mesh for Lichtenstein hernia repair

    DEFF Research Database (Denmark)

    Jorgensen, L N; Sommer, T; Assaadzadeh, S;

    2012-01-01

    between the groups in postoperative complications (33·7 versus 40·4 per cent; P = 0·215), rate of recurrent hernia within 1 year (1·2 per cent in both groups) or quality of life. CONCLUSION: The avoidance of suture fixation using a self-gripping mesh was not accompanied by a reduction in chronic symptoms......BACKGROUND: Many patients develop discomfort after open repair of a groin hernia. It was hypothesized that suture fixation of the mesh is a cause of these symptoms. METHODS: This patient- and assessor-blinded randomized multicentre clinical trial compared a self-gripping mesh (Parietene Progrip......(®) ) and sutured mesh for open primary repair of uncomplicated inguinal hernia by the Lichtenstein technique. Patients were assessed before surgery, on the day of operation, and at 1 and 12 months after surgery. The primary endpoint was moderate or severe symptoms after 12 months, including a combination...

  12. Moving mesh generation with a sequential approach for solving PDEs

    DEFF Research Database (Denmark)

    of physical and mesh equations suffers typically from long computation time due to highly nonlinear coupling between the two equations. Moreover, the extended system (physical and mesh equations) may be sensitive to the tuning parameters such as a temporal relaxation factor. It is therefore useful to design...... adaptive grid method (local refinement by adding/deleting the meshes at a discrete time level) as well as of efficiency for the dynamic adaptive grid method (or moving mesh method) where the number of meshes is not changed. For illustration, a phase change problem is solved with the decomposition algorithm.......In moving mesh methods, physical PDEs and a mesh equation derived from equidistribution of an error metrics (so-called the monitor function) are simultaneously solved and meshes are dynamically concentrated on steep regions (Lim et al., 2001). However, the simultaneous solution procedure...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-05-01

    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.

  14. On combining Laplacian and optimization-based mesh smoothing techniques

    Energy Technology Data Exchange (ETDEWEB)

    Freitag, L.A.

    1997-07-01

    Local mesh smoothing algorithms have been shown to be effective in repairing distorted elements in automatically generated meshes. The simplest such algorithm is Laplacian smoothing, which moves grid points to the geometric center of incident vertices. Unfortunately, this method operates heuristically and can create invalid meshes or elements of worse quality than those contained in the original mesh. In contrast, optimization-based methods are designed to maximize some measure of mesh quality and are very effective at eliminating extremal angles in the mesh. These improvements come at a higher computational cost, however. In this article the author proposes three smoothing techniques that combine a smart variant of Laplacian smoothing with an optimization-based approach. Several numerical experiments are performed that compare the mesh quality and computational cost for each of the methods in two and three dimensions. The author finds that the combined approaches are very cost effective and yield high-quality meshes.

  15. Oestradiol-releasing Biodegradable Mesh Stimulates Collagen Production and Angiogenesis: An Approach to Improving Biomaterial Integration in Pelvic Floor Repair.

    Science.gov (United States)

    Mangır, Naşide; Hillary, Christopher J; Chapple, Christopher R; MacNeil, Sheila

    2017-06-03

    Polypropylene meshes cause severe complications in some patients. Materials that are biomechanically compatible and can better integrate into host tissues are urgently needed. To design an oestradiol-releasing electrospun poly-l-lactic acid (PLA) mesh and evaluate its ability to stimulate new extracellular matrix and new blood vessel formation. Human adipose derived mesenchymal cells (ADMSC) were isolated from fat. PLA meshes with micro- to nano-sized fibres containing 1%, 5%, and 10% oestradiol were constructed and used for in vitro and in vivo experiments. The angiogenic potential of the fibrous meshes was evaluated using an in vivo chorioallantoic membrane and an in vitro chick aortic arch assays. Oestradiol release was measured fluorometrically. The effect of fibrous meshes on proliferation and extracellular matrix (ECM) production of ADMSC was assessed using immunohistology. Mechanical properties were tested using a tensiometer. The ultrastructure of the mesh was not affected by the inclusion of oestradiol and mechanical properties were only slightly modified. Oestradiol was released from PLA meshes over a 5-mo period. ADMSCs cultured on oestradiol-releasing PLA meshes produced more ECM involving collagen I, collagen III, and elastin. Oestradiol-releasing meshes doubled new blood vessel formation in the chorioallantoic membrane assay (p=0.001) and outgrowth of pro-angiogenic cells in the aortic arch assay (p=0.001). Further studies in longer-term animal models are required to confirm these results. Oestradiol-releasing PLA meshes increase ECM production and stimulate angiogenesis. As such, they are promising candidate materials to be used in pelvic floor repair and to improve the initial healing phase of a repair material following implantation. In this study, we designed a tissue engineered material to be used to support weakened pelvic floor tissues in women to avoid the complications associated with current surgical mesh. Our results showed that this

  16. Orbital and Maxillofacial Computer Aided Surgery: Patient-Specific Finite Element Models To Predict Surgical Outcomes

    CERN Document Server

    Luboz, V; Swider, P; Payan, Y; Luboz, Vincent; Chabanas, Matthieu; Swider, Pascal; Payan, Yohan

    2005-01-01

    This paper addresses an important issue raised for the clinical relevance of Computer-Assisted Surgical applications, namely the methodology used to automatically build patient-specific Finite Element (FE) models of anatomical structures. From this perspective, a method is proposed, based on a technique called the Mesh-Matching method, followed by a process that corrects mesh irregularities. The Mesh-Matching algorithm generates patient-specific volume meshes from an existing generic model. The mesh regularization process is based on the Jacobian matrix transform related to the FE reference element and the current element. This method for generating patient-specific FE models is first applied to Computer-Assisted maxillofacial surgery, and more precisely to the FE elastic modelling of patient facial soft tissues. For each patient, the planned bone osteotomies (mandible, maxilla, chin) are used as boundary conditions to deform the FE face model, in order to predict the aesthetic outcome of the surgery. Seven F...

  17. Explicit inverse distance weighting mesh motion for coupled problems

    OpenAIRE

    Witteveen, J.A.S.; Bijl, H.

    2009-01-01

    An explicit mesh motion algorithm based on inverse distance weighting interpolation is presented. The explicit formulation leads to a fast mesh motion algorithm and an easy implementation. In addition, the proposed point-by-point method is robust and flexible in case of large deformations, hanging nodes, and parallelization. Mesh quality results and CPU time comparisons are presented for triangular and hexahedral unstructured meshes in an airfoil flutter fluid-structure interaction problem.

  18. On Reducing Delay in Mesh-Based P2P Streaming: A Mesh-Push Approach

    Science.gov (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.

  19. Interfacial oxidations of pure titanium and titanium alloys with investments.

    Science.gov (United States)

    Ban, S; Watanabe, T; Mizutani, N; Fukui, H; Hasegawa, J; Nakamura, H

    2000-12-01

    External oxides of a commercially pure titanium (cpTi), Ti6Al4V alloy, and an experimental beta-type titanium alloy (Ti 53.4 wt%, Nb 29 wt%, Ta 13 wt%, and Zr 4.6 wt%) were characterized after heating to 600, 900, 1150, and 1400 degrees C in contact with three types of investments (alumina cement, magnesia cement, and phosphate-bonded) in air. XRD studies demonstrated that MgO, Li2TiO3 and/or Li2Ti3O7 were formed through reactions with the metal and the constituents in the magnesia cement-investment after heating to 900, 1150, and 1400 degrees C. Except for these conditions, TiO2 (rutile) was only formed on cpTi. For titanium alloys, the other components apart from Ti also formed simple and complex oxides such as Al2O3 and Al2TiO5 on Ti6Al4V, and Zr0.25Ti0.75Nb2O7 on the beta-type titanium alloy. However, no oxides containing V or Ta were formed. These results suggest that the constituents of titanium alloys reacted with the investment oxides and atmospheric oxygen to form external oxides due to the free energy of oxide formation and the concentration of each element on the metal surface.

  20. Cell response of anodized nanotubes on titanium and titanium alloys.

    Science.gov (United States)

    Minagar, Sepideh; Wang, James; Berndt, Christopher C; Ivanova, Elena P; Wen, Cuie

    2013-09-01

    Titanium and titanium alloy implants that have been demonstrated to be more biocompatible than other metallic implant materials, such as Co-Cr alloys and stainless steels, must also be accepted by bone cells, bonding with and growing on them to prevent loosening. Highly ordered nanoporous arrays of titanium dioxide that form on titanium surface by anodic oxidation are receiving increasing research interest due to their effectiveness in promoting osseointegration. The response of bone cells to implant materials depends on the topography, physicochemistry, mechanics, and electronics of the implant surface and this influences cell behavior, such as adhesion, proliferation, shape, migration, survival, and differentiation; for example the existing anions on the surface of a titanium implant make it negative and this affects the interaction with negative fibronectin (FN). Although optimal nanosize of reproducible titania nanotubes has not been reported due to different protocols used in studies, cell response was more sensitive to titania nanotubes with nanometer diameter and interspace. By annealing, amorphous TiO2 nanotubes change to a crystalline form and become more hydrophilic, resulting in an encouraging effect on cell behavior. The crystalline size and thickness of the bone-like apatite that forms on the titania nanotubes after implantation are also affected by the diameter and shape. This review describes how changes in nanotube morphologies, such as the tube diameter, the thickness of the nanotube layer, and the crystalline structure, influence the response of cells.

  1. A testing preocedure for the evaluation of directional mesh bias

    NARCIS (Netherlands)

    Slobbe, A.T.; Hendriks, M.A.N.; Rots, J.G.

    2013-01-01

    This paper presents a dedicated numerical test that enables to assess the directional mesh bias of constitutive models in a systematic way. The test makes use of periodic boundary conditions, by which strain localization can be analyzed for different mesh alignments with preservation of mesh uniform

  2. Multiphase flow of immiscible fluids on unstructured moving meshes

    DEFF Research Database (Denmark)

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

    2012-01-01

    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...

  3. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Science.gov (United States)

    2010-04-01

    ... 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...

  4. Titanium nanostructures for biomedical applications

    Science.gov (United States)

    Kulkarni, M.; Mazare, A.; Gongadze, E.; Perutkova, Š.; Kralj-Iglič, V.; Milošev, I.; Schmuki, P.; Iglič, A.; Mozetič, M.

    2015-02-01

    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties.

  5. Evaluation of a fully absorbable poly-4-hydroxybutyrate/absorbable barrier composite mesh in a porcine model of ventral hernia repair.

    Science.gov (United States)

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

    2016-09-01

    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.

  6. Gender differences in the acquisition of surgical skills

    DEFF Research Database (Denmark)

    Ali, Amir; Subhi, Yousif; Ringsted, Charlotte

    2015-01-01

    BACKGROUND: Females are less attracted than males to surgical specialties, which may be due to differences in the acquisition of skills. The aim of this study was to systematically review studies that investigate gender differences in the acquisition of surgical skills. METHODS: We performed...... a comprehensive database search using relevant search phrases and MeSH terms. We included studies that investigated the role of gender in the acquisition of surgical skills. RESULTS: Our search yielded 247 studies, 18 of which were found to be eligible and were therefore included. These studies included a total...... conditions). Male medical students tended to outperform females, while no gender differences were found among residents. Gaming experience and interest in surgery correlated with better acquisition of surgical skills, regardless of gender. Although initial levels of surgical abilities seemed lower among...

  7. Single-Incision Laparoscopic Intraperitoneal Onlay Mesh Repair for the Treatment of Multiple Recurrent Inguinal Hernias

    Science.gov (United States)

    Tran, Kim; Zajkowska, Marta; Lam, Vincent; Hawthorne, Wayne

    2014-01-01

    Introduction: Despite an exponential rise in laparoscopic surgery for inguinal herniorrhaphy, overall recurrence rates have remained unchanged. Therefore, an increasing number of patients present with recurrent hernias after having failed anterior and laparoscopic repairs. This study reports our experience with single-incision laparoscopic (SIL) intraperitoneal onlay mesh (IPOM) repair for these hernias. Materials and methods: All patients referred with multiply recurrent inguinal hernias underwent SIL-IPOM from November 1 2009 to October 30 2013. A 2.5-cm infraumbilical incision was made and a SIL surgical port was placed intraperitoneally. Modified dissection techniques, namely, “chopsticks” and “inline” dissection, 5.5 mm/52 cm/30° angled laparoscope and conventional straight dissecting instruments were used. The peritoneum was incised above the symphysis pubis and dissection continued laterally and proximally raising an inferior flap, below a previous extraperitoneal mesh, while reducing any direct/indirect/femoral/cord lipoma before placement of antiadhesive mesh that was fixed into the pubic ramus as well as superiorly with nonabsorbable tacks before fixing its inferior border with fibrin sealant. The inferior peritoneal flap was then tacked back onto the mesh. Results: There were 9 male patients who underwent SIL-IPOM. Mean age was 55 years old and mean body mass index was 26.8 kg/m2. Mean mesh size was 275 cm2. Mean operation time was 125 minutes with hospital stay of 1 day and umbilical scar length of 21 mm at 4 weeks' follow-up. There were no intraoperative/postoperative complications, port-site hernias, chronic groin pain, or recurrence with mean follow-up of 20 months. Conclusions: Multiply recurrent inguinal hernias after failed conventional anterior and laparoscopic repairs can be treated safely and efficiently with SIL-IPOM. PMID:25392643

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

    Directory of Open Access Journals (Sweden)

    Tanya M Nazemi

    2007-01-01

    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

  9. A comparison of outcomes and cost in VHWG grade II hernias between Rives-Stoppa synthetic mesh hernia repair versus underlay biologic mesh repair.

    Science.gov (United States)

    Fischer, J P; Basta, M N; Mirzabeigi, M N; Kovach, S J

    2014-01-01

    The current literature is void of evidence-based guidelines regarding optimal choice of mesh. We aim to perform a comparative outcome analysis of synthetic mesh and acellular dermal matrix (ADM) in Ventral Hernia Working Grade (VHWG) grade II hernias with primary fascial closure. A retrospective review of patients undergoing ventral hernia repair (VHR) by the senior author (S.J.K.) from 2007 to 2012 was performed. Patients undergoing VHR with primary fascial closure were risk stratified using the VHWG defined grading system. Seventy-two patients met the abovementioned inclusion criteria with 45 receiving synthetic mesh and 27 receiving ADM. The mean length of follow-up was 12.1 ± 9.1 months. Patients were, on average, 53.2 ± 11.6 years of age with a BMI of 33.9 ± 10.6 kg/m(2). The overall incidence of surgical site occurrence (SSO) in the cohort was 41.7 % and the incidence of hernia recurrence was 5.6 %. 30-day mortality was 1.2 %. Bivariate analysis demonstrated that obesity (P = 0.038) and number of comorbidities (P = 0.043) were associated with SSO. Bivariate analysis demonstrated that prior failed hernia, use of ADM, and operative time were associated with higher rates of hernia recurrence; however, adjusted multivariate regression found only prior failed hernia (OR = 4.1, P = 0.03) and biologic mesh (OR = 3.4, P = 0.046) to be independently associated with recurrent hernia. Comparison of mesh types revealed few differences in preoperative or operative characteristics between synthetic mesh and acellular dermal matrices (ADM). The rate of hernia recurrence was significantly higher with ADM (14.8 % vs. 0.0 %, P = 0.017). Patients receiving ADM repairs incurred significantly greater cost ($56,142.1 ± 54,775.5 vs. $30,599.8 ± 39,000.8, P hernia recurrences and lower cost utilization at 1-year. Prognostic/risk category, level III.

  10. Plasma quench production of titanium from titanium tetrachloride

    Energy Technology Data Exchange (ETDEWEB)

    Sears, J.W.

    1994-10-01

    This project, Plasma Quench Production of Titanium from Titanium Tetrachloride, centers on developing a technique for rapidly quenching the high temperature metal species and preventing back reactions with the halide. The quenching technique chosen uses the temperature drop produced in a converging/diverging supersonic nozzle. The rapid quench provided by this nozzle prevents the back reaction of the halide and metal. The nature of the process produces nanosized particles (10 to 100 nm). The powders are collected by cyclone separators, the hydrogen flared, and the acid scrubbed. Aluminum and titanium powders have been produced in the laboratory-scale device at 1 gram per hour. Efforts to date to scale up this process have not been successful.

  11. Plasmonic titanium nitride nanostructures for perfect absorbers

    DEFF Research Database (Denmark)

    Guler, Urcan; Li, Wen-Wei; Kinsey, Nathaniel

    2013-01-01

    We propose a metamaterial based perfect absorber in the visible region, and investigate the performance of titanium nitride as an alternative plasmonic material. Numerical and experimental results reveal that titanium nitride performs better than gold as a plasmonic absorbing material...

  12. Lightweight Protective Coatings For Titanium Alloys

    Science.gov (United States)

    Wiedemann, Karl E.; Taylor, Patrick J.; Clark, Ronald K.

    1992-01-01

    Lightweight coating developed to protect titanium and titanium aluminide alloys and titanium-matrix composite materials from attack by environment when used at high temperatures. Applied by sol-gel methods, and thickness less than 5 micrometers. Reaction-barrier and self-healing diffusion-barrier layers combine to protect titanium alloy against chemical attack by oxygen and nitrogen at high temperatures with very promising results. Can be extended to protection of other environmentally sensitive materials.

  13. Anodic growth of titanium dioxide nanostructures

    DEFF Research Database (Denmark)

    2010-01-01

    Disclosed is a method of producing nanostructures of titanium dioxide (TiO 2 ) by anodisation of titanium (Ti) in an electrochemical cell, comprising the steps of: immersing a non-conducting substrate coated with a layer of titanium, defined as the anode, in an electrolyte solution...... an electrical contact to the layer of titanium on the anode, where the electrical contact is made in the electrolyte solution...

  14. Laparoscopic Total Extraperitoneal (TEP) Inguinal Hernia Repair Using 3-dimensional Mesh Without Mesh Fixation.

    Science.gov (United States)

    Aliyazicioglu, Tolga; Yalti, Tunc; Kabaoglu, Burcak

    2017-08-01

    Approximately one fifth of patients suffer from inguinal pain after laparoscopic total extraperitoneal (TEP) inguinal hernia repair. There is existing literature suggesting that the staples used to fix the mesh can cause postoperative inguinal pain. In this study, we describe our experience with laparoscopic TEP inguinal hernia surgery using 3-dimensional mesh without mesh fixation, in our institution. A total of 300 patients who had undergone laparoscopic TEP inguinal hernia repair with 3-dimensional mesh in VKV American Hospital, Istanbul from November 2006 to November 2015 were studied retrospectively. Using the hospital's electronic archive, we studied patients' selected parameters, which are demographic features (age, sex), body mass index, hernia locations and types, duration of operations, preoperative and postoperative complications, duration of hospital stays, cost of surgery, need for analgesics, time elapsed until returning to daily activities and work. A total of 300 patients underwent laparoscopic TEP hernia repair of 437 inguinal hernias from November 2006 to November 2015. Of the 185 patients, 140 were symptomatic. Mean duration of follow-up was 48 months (range, 6 to 104 mo). The mean duration of surgery was 55 minutes for bilateral hernia repair, and 38 minutes for unilateral hernia repair. The mean duration of hospital stay was 0.9 day. There was no conversion to open surgery. In none of the cases the mesh was fixated with either staples or fibrin glue. Six patients (2%) developed seroma that were treated conservatively. One patient had inguinal hernia recurrence. One patient had preperitoneal hematoma. One patient operated due to indirect right-sided hernia developed right-sided hydrocele. One patient had wound dehiscence at the umbilical port entry site. Chronic pain developed postoperatively in 1 patient. Ileus developed in 1 patient. Laparoscopic TEP inguinal repair with 3-dimensional mesh without mesh fixation can be performed as safe as

  15. Meshed split skin graft for extensive vitiligo

    Directory of Open Access Journals (Sweden)

    Srinivas C

    2004-05-01

    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.

  16. Variational mesh segmentation via quadric surface fitting

    KAUST Repository

    Yan, Dongming

    2012-11-01

    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.

  17. Capacity estimation of wireless mesh networks

    OpenAIRE

    2005-01-01

    Resumo: Este trabalho apresenta uma estimação da capacidade das redes sem fio tipo Mesh. As redes deste tipo têm topologias e padrões de tráfego únicos que as diferenciam das redes sem fio convencionais. Nas redes sem fio tipo mesh os nós atuam como clientes e como servidores e o tráfego e encaminhado para uma ou várias gateways em um modo multi-salto. A estimação da capacidade é baseada em estudos da Camada Física e MAC. Efeitos da propagação do canal são avaliados Abstract: This work add...

  18. Nondispersive optical activity of meshed helical metamaterials.

    Science.gov (United States)

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

    2014-11-17

    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.

  19. Energy-efficient wireless mesh networks

    CSIR Research Space (South Africa)

    Ntlatlapa, N

    2007-06-01

    Full Text Available ­deficient areas such as rural areas in  Africa.  Index   Terms—Energy   efficient   design,   Wireless  Mesh networks, Network Protocols I. INTRODUCTION The  objectives  of   this   research  group   are   the  application   and   adaptation   of   existing   wireless  local   area...   networks,   especially   those   based   on  802.11 standard, for   the energy­efficient  wireless  mesh network (EE­WMN) architectures, protocols  and   controls.   In   addition   to   the   WMN   regular  features   of   self...

  20. Adaptive upscaling with the dual mesh method

    Energy Technology Data Exchange (ETDEWEB)

    Guerillot, D.; Verdiere, S.

    1997-08-01

    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.

  1. Gamra: Simple Meshes for Complex Earthquakes

    CERN Document Server

    Landry, Walter

    2016-01-01

    The static offsets caused by earthquakes are well described by elastostatic models with a discontinuity in the displacement along the fault. A traditional approach to model this discontinuity is to align the numerical mesh with the fault and solve the equations using finite elements. However, this distorted mesh can be difficult to generate and update. We present a new numerical method, inspired by the Immersed Interface Method, for solving the elastostatic equations with embedded discontinuities. This method has been carefully designed so that it can be used on parallel machines on an adapted finite difference grid. We have implemented this method in Gamra, a new code for earth modelling. We demonstrate the correctness of the method with analytic tests, and we demonstrate its practical performance by solving a realistic earthquake model to extremely high precision.

  2. Electrostatic PIC with adaptive Cartesian mesh

    CERN Document Server

    Kolobov, Vladimir I

    2016-01-01

    We describe an initial implementation of an electrostatic Particle-in-Cell (ES-PIC) module with adaptive Cartesian mesh in our Unified Flow Solver framework. Challenges of PIC method with cell-based adaptive mesh refinement (AMR) are related to a decrease of the particle-per-cell number in the refined cells with a corresponding increase of the numerical noise. The developed ES-PIC solver is validated for capacitively coupled plasma, its AMR capabilities are demonstrated for simulations of streamer development during high-pressure gas breakdown. It is shown that cell-based AMR provides a convenient particle management algorithm for exponential multiplications of electrons and ions in the ionization events.

  3. Mesh convergence study for hydraulic turbine draft-tube

    Science.gov (United States)

    Devals, C.; Vu, T. C.; Zhang, Y.; Dompierre, J.; Guibault, F.

    2016-11-01

    Computational flow analysis is an essential tool for hydraulic turbine designers. Grid generation is the first step in the flow analysis process. Grid quality and solution accuracy are strongly linked. Even though many studies have addressed the issue of mesh independence, there is still no definitive consensus on mesh best practices, and research on that topic is still needed. This paper presents a mesh convergence study for turbulence flow in hydraulic turbine draft- tubes which represents the most challenging turbine component for CFD predictions. The findings from this parametric study will be incorporated as mesh control rules in an in-house automatic mesh generator for turbine components.

  4. Overlay Share Mesh for Interactive Group Communication with High Dynamic

    Institute of Scientific and Technical Information of China (English)

    WU Yan-hua; CAI Yun-ze; XU Xiao-ming

    2007-01-01

    An overlay share mesh infrastructure is presented for high dynamic group communication systems, such as distributed interactive simulation (DIS) and distributed virtual environments (DVE). Overlay share mesh infrastructure can own better adapting ability for high dynamic group than tradition multi-tree multicast infrastructure by sharing links among different groups. The mechanism of overlay share mesh based on area of interest (AOI) was discussed in detail in this paper. A large number of simulation experiments were done and the permance of mesh infrastructure was studied. Experiments results proved that overlay mesh infrastructure owns better adaptability than traditional multi-tree infrastructure for high dynamic group communication systems.

  5. Diffusive mesh relaxation in ALE finite element numerical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Dube, E.I.

    1996-06-01

    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.

  6. Effects of mesh resolution on hypersonic heating prediction

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Aeroheating prediction is a challenging and critical problem for the design and optimization of hypersonic vehicles.One challenge is that the solution of the Navier-Stokes equations strongly depends on the computational mesh.In this letter,the effect of mesh resolution on heat flux prediction is studied.It is found that mesh-independent solutions can be obtained using fine mesh,whose accuracy is confirmed by results from kinetic particle simulation.It is analyzed that mesh-induced numerical error comes m...

  7. 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

    2015-01-01

    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.

  8. Wireless experiments on a Motorola mesh testbed.

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-06-01

    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.

  9. Airbag Mapped Mesh Auto-Flattening Method

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jinhuan; MA Chunsheng; BAI Yuanli; HUANG Shilin

    2005-01-01

    Current software cannot easily model an airbag to be flattened without wrinkles. This paper improves the modeling efficiency using the initial metric method to design a mapped mesh auto-flattening algorithm. The element geometric transformation matrix was obtained using the theory of computer graphics. The algorithm proved to be practical for modeling a passenger-side airbag model. The efficiency and precision of modeling airbags are greatly improved by this method.

  10. Gradient Domain Mesh Deformation - A Survey

    Institute of Scientific and Technical Information of China (English)

    Wei-Wei Xu; Kun Zhou

    2009-01-01

    This survey reviews the recent development of gradient domain mesh deformation method. Different to other deformation methods, the gradient domain deformation method is a surface-based, variational optimization method. It directly encodes the geometric details in differential coordinates, which are also called Laplacian coordinates in literature. By preserving the Laplacian coordinates, the mesh details can be well preserved during deformation. Due to the locality of the Laplacian coordinates, the variational optimization problem can be casted into a sparse linear system. Fast sparse linear solver can be adopted to generate deformation result interactively, or even in real-time. The nonlinear nature of gradient domain mesh deformation leads to the development of two categories of deformation methods: linearization methods and nonlinear optimization methods. Basically, the linearization methods only need to solve the linear least-squares system once. They are fast, easy to understand and control, while the deformation result might be suboptimal. Nonlinear optimization methods can reach optimal solution of deformation energy function by iterative updating. Since the computation of nonlinear methods is expensive, reduced deformable models should be adopted to achieve interactive performance. The nonlinear optimization methods avoid the user burden to input transformation at deformation handles, and they can be extended to incorporate various nonlinear constraints, like volume constraint, skeleton constraint, and so on. We review representative methods and related approaches of each category comparatively and hope to help the user understand the motivation behind the algorithms. Finally, we discuss the relation between physical simulation and gradient domain mesh deformation to reveal why it can achieve physically plausible deformation result.

  11. Solid Mesh Registration for Radiotherapy Treatment Planning

    DEFF Research Database (Denmark)

    Noe, Karsten Østergaard; Sørensen, Thomas Sangild

    2010-01-01

    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 usi...... 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....

  12. Performance Evaluation of Coded Meshed Networks

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...... and/or high loss probabilities. We show that a store and forward scheme outperforms COPE under some channel conditions, while CORE yields 3dB gains....

  13. The use of nontreated mosquito-net mesh cloth for a tension free inguinal hernia repair: Our experience

    Directory of Open Access Journals (Sweden)

    Felix O Oribabor

    2015-01-01

    Full Text Available Introduction: The prohibitive costs and scarcity of the imported prosthetic mesh for hernioplasty, has prevented its widespread use in most developing countries. We then set out to ascertain the outcome, complications (undue pain, wound infection, recurrence, and mesh extrusion and cost implications in the use of a nontreated mosquito-net for inguinal hernioplasty. Materials and Methods: A prospective study of all consecutive adult patients with uncomplicated inguinal hernia who were admitted for open herniorrhaphy between January 2012 and December, 2013 at the Federal Medical Centre, Ido - Ekiti, South West, Nigeria. A sheet of the nontreated mosquito-net mesh 10 cm Χ 8 cm, autoclaved, a day prior to surgery was used for each patient′s hernia repair. The operation sites were exposed and examined 3 rd and 6 th postoperative days. Findings were documented for analysis. Result: A total of 130 adult patients were recruited for this study of which 115 of the patients were males and 15 were females. Forty-four (41.53% had inguinal hernia and 76 (58.46% of them had inguinoscrotal hernia. They all had successful repair and were followed-up for complications for a period of 6 weeks to 6 months at the surgical out-patient department. Conclusion: Locally-sourced and autoclaved mosquito-net mesh is an effective alternative for hernioplasty especially in situations where commercial mesh is not readily available or affordable.

  14. 21 CFR 73.575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.575 Section 73.575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.575 Titanium dioxide. (a) Identity. (1) The color additive titanium dioxide is synthetically prepared TiO2, free from admixture with other substances. (2)...

  15. 21 CFR 73.2575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  16. 21 CFR 73.1575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  17. 40 CFR 180.1195 - Titanium dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or...

  18. 21 CFR 73.3126 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  19. Particle Mesh Hydrodynamics for Astrophysics Simulations

    Science.gov (United States)

    Chatelain, Philippe; Cottet, Georges-Henri; Koumoutsakos, Petros

    We present a particle method for the simulation of three dimensional compressible hydrodynamics based on a hybrid Particle-Mesh discretization of the governing equations. The method is rooted on the regularization of particle locations as in remeshed Smoothed Particle Hydrodynamics (rSPH). The rSPH method was recently introduced to remedy problems associated with the distortion of computational elements in SPH, by periodically re-initializing the particle positions and by using high order interpolation kernels. In the PMH formulation, the particles solely handle the convective part of the compressible Euler equations. The particle quantities are then interpolated onto a mesh, where the pressure terms are computed. PMH, like SPH, is free of the convection CFL condition while at the same time it is more efficient as derivatives are computed on a mesh rather than particle-particle interactions. PMH does not detract from the adaptive character of SPH and allows for control of its accuracy. We present simulations of a benchmark astrophysics problem demonstrating the capabilities of this approach.

  20. Mesh Learning for Classifying Cognitive Processes

    CERN Document Server

    Ozay, Mete; Öztekin, Uygar; Vural, Fatos T Yarman

    2012-01-01

    The major goal of this study is to model the encoding and retrieval operations of the brain during memory processing, using statistical learning tools. The suggested method assumes that the memory encoding and retrieval processes can be represented by a supervised learning system, which is trained by the brain data collected from the functional Magnetic Resonance (fMRI) measurements, during the encoding stage. Then, the system outputs the same class labels as that of the fMRI data collected during the retrieval stage. The most challenging problem of modeling such a learning system is the design of the interactions among the voxels to extract the information about the underlying patterns of brain activity. In this study, we suggest a new method called Mesh Learning, which represents each voxel by a mesh of voxels in a neighborhood system. The nodes of the mesh are a set of neighboring voxels, whereas the arc weights are estimated by a linear regression model. The estimated arc weights are used to form Local Re...

  1. Parallel object-oriented adaptive mesh refinement

    Energy Technology Data Exchange (ETDEWEB)

    Balsara, D.; Quinlan, D.J.

    1997-04-01

    In this paper we study adaptive mesh refinement (AMR) for elliptic and hyperbolic systems. We use the Asynchronous Fast Adaptive Composite Grid Method (AFACX), a parallel algorithm based upon the of Fast Adaptive Composite Grid Method (FAC) as a test case of an adaptive elliptic solver. For our hyperbolic system example we use TVD and ENO schemes for solving the Euler and MHD equations. We use the structured grid load balancer MLB as a tool for obtaining a load balanced distribution in a parallel environment. Parallel adaptive mesh refinement poses difficulties in expressing both the basic single grid solver, whether elliptic or hyperbolic, in a fashion that parallelizes seamlessly. It also requires that these basic solvers work together within the adaptive mesh refinement algorithm which uses the single grid solvers as one part of its adaptive solution process. We show that use of AMR++, an object-oriented library within the OVERTURE Framework, simplifies the development of AMR applications. Parallel support is provided and abstracted through the use of the P++ parallel array class.

  2. Mesh deployable antenna mechanics testing method

    Science.gov (United States)

    Jiang, Li

    Rapid development in spatial technologies and continuous expansion of astronautics applications require stricter and stricter standards in spatial structure. Deployable space structure as a newly invented structural form is being extensively adopted because of its characteristic (i.e. deployability). Deployable mesh reflector antenna is a kind of common deployable antennas. Its reflector consists in a kind of metal mesh. Its electrical properties are highly dependent on its mechanics parameters (including surface accuracy, angle, and position). Therefore, these mechanics parameters have to be calibrated. This paper presents a mesh antenna mechanics testing method that employs both an electronic theodolite and a laser tracker. The laser tracker is firstly used to measure the shape of radial rib deployable antenna. The measurement data are then fitted to a paraboloid by means of error compensation. Accordingly, the focus and the focal axis of the paraboloid are obtained. The following step is to synchronize the coordinate systems of the electronic theodolite and the measured antenna. Finally, in a microwave anechoic chamber environment, the electromechanical axis is calibrated. Testing results verify the effectiveness of the presented method.

  3. MeSH Now: automatic MeSH indexing at PubMed scale via learning to rank.

    Science.gov (United States)

    Mao, Yuqing; Lu, Zhiyong

    2017-04-17

    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 F1-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. http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/Demo/MeSHNow/ .

  4. Effect of microstructure on the elasto-viscoplastic deformation of dual phase titanium structures

    Science.gov (United States)

    Ozturk, Tugce; Rollett, Anthony D.

    2017-08-01

    The present study is devoted to the creation of a process-structure-property database for dual phase titanium alloys, through a synthetic microstructure generation method and a mesh-free fast Fourier transform based micromechanical model that operates on a discretized image of the microstructure. A sensitivity analysis is performed as a precursor to determine the statistically representative volume element size for creating 3D synthetic microstructures based on additively manufactured Ti-6Al-4V characteristics, which are further modified to expand the database for features of interest, e.g., lath thickness. Sets of titanium hardening parameters are extracted from literature, and The relative effect of the chosen microstructural features is quantified through comparisons of average and local field distributions.

  5. Data-Parallel Mesh Connected Components Labeling and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Cyrus; Childs, Hank; Gaither, Kelly

    2011-04-10

    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.

  6. Data-Parallel Mesh Connected Components Labeling and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Cyrus; Childs, Hank; Gaither, Kelly

    2011-04-10

    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.

  7. Photonuclear reactions on titanium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Belyshev, S. S. [Moscow State University (Russian Federation); Dzhilavyan, L. Z. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Ishkhanov, B. S.; Kapitonov, I. M. [Moscow State University (Russian Federation); Kuznetsov, A. A., E-mail: kuznets@depni.sinp.msu.ru; Orlin, V. N.; Stopani, K. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

    2015-03-15

    The photodisintegration of titanium isotopes in the giant-dipole-resonance energy region is studied by the photon-activation method. Bremsstrahlung photons whose spectrum has the endpoint energy of 55 MeV is used. The yields and integrated cross sections are determined for photoproton reactions on the titanium isotopes {sup 47,48,49,50}Ti. The respective experimental results are compared with their counterparts calculated on the basis of the TALYS code and a combined photonucleon-reaction model. The TALYS code disregards the isospin structure of the giant dipole resonance and is therefore unable to describe the yield of photoproton reactions on the heavy titanium isotopes {sup 49,50}Ti.

  8. Laser bioengineering of glass-titanium implants surface

    Science.gov (United States)

    Lusquiños, F.; Arias-González, F.; Penide, J.; del Val, J.; Comesaña, R.; Quintero, F.; Riveiro, A.; Boutinguiza, M.; Pascual, M. J.; Durán, A.; Pou, J.

    2013-11-01

    Osseointegration is the mean challenge when surgical treatments fight against load-bearing bone diseases. Absolute bone replacement by a synthetic implant has to be completed not only from the mechanics point of view, but also from a biological approach. Suitable strength, resilience and stress distribution of titanium alloy implants are spoiled by the lack of optimal biological characteristics. The inert quality of extra low interstitial titanium alloy, which make it the most attractive metallic alloy for biomedical applications, oppose to an ideal surface with bone cell affinity, and capable to stimulate bone attachment bone growth. Diverse laser treatments have been proven as effective tools to modify surface properties, such as wettability in contact to physiological fluids, or osteoblast guided and slightly enhanced attachment. The laser surface cladding can go beyond by providing titanium alloy surfaces with osteoconduction and osteoinduction properties. In this research work, the laser radiation is used to produce bioactive glass coatings on Ti6Al4V alloy substrates. Specific silicate bioactive glass compositions has been investigated to achieve suitable surface tension and viscosity temperature behavior during processing, and to provide with the required release of bone growth gene up regulation agents in the course of resorption mediated by physiological fluids. The produced coatings and interfaces, the surface osteoconduction properties, and the chemical species release in simulated physiological fluid were characterized by scanning electron microscopy (SEM), hot stage microscopy (HSM), X-ray diffraction (XRD), X ray fluorescence (XRF), and Fourier transform infrared spectroscopy (FTIR).

  9. Self-activated mesh device using shape memory alloy for periosteal expansion osteogenesis.

    Science.gov (United States)

    Yamauchi, Kensuke; Takahashi, Tetsu; Tanaka, Kenko; Nogami, Shinnosuke; Kaneuji, Takeshi; Kanetaka, Hiroyasu; Miyazaki, Toshiki; Lethaus, Bernd; Kessler, Peter

    2013-07-01

    The present study evaluated the use of this self-activated shape memory alloy (SMA) device, with a focus on its effects in the region under the periosteum. Twelve Japanese white rabbits were used in this study. The device was inserted under the periosteum at the forehead. In the experimental group, the device was pushed, bent, and attached to the bone surface and fixed with a titanium screw. In control group, the device was only inserted under the periosteum. After 14 days, the screw was removed and the mesh was activated in the experimental group. Rabbits were sacrificed 5 and 8 weeks after the operation and newly formed bone was histologically and radiographically evaluated. The quantitative data by the area and the occupation of newly formed bone indicated that the experimental group had a higher volume of new bone than the control group at each consolidation period. Histologically, some newly formed bone was observed and most of the subperiosteal space underneath the device was filled with fibrous tissue, and a thin layer of immature bone was observed in the control group. In the experimental group, multiple dome-shaped bones, outlined by thin and scattered trabeculae, were clearly observed under the SMA mesh device. The use of self-activated devices for the periosteal expansion technique may make it possible to avoid donor site morbidity, trans-skin activation rods, any bone-cutting procedure, and the following intermittent activation procedure.

  10. Effect of whitening toothpaste on titanium and titanium alloy surfaces.

    Science.gov (United States)

    Faria, Adriana Cláudia Lapria; Bordin, Angelo Rafael de Vito; Pedrazzi, Vinícius; Rodrigues, Renata Cristina Silveira; Ribeiro, Ricardo Faria

    2012-01-01

    Dental implants have increased the use of titanium and titanium alloys in prosthetic applications. Whitening toothpastes with peroxides are available for patients with high aesthetic requirements, but the effect of whitening toothpastes on titanium surfaces is not yet known, although titanium is prone to fluoride ion attack. Thus, the aim of the present study was to compare Ti-5Ta alloy to cp Ti after toothbrushing with whitening and conventional toothpastes. Ti-5Ta (%wt) alloy was melted in an arc melting furnace and compared with cp Ti. Disks and toothbrush heads were embedded in PVC rings to be mounted onto a toothbrushing test apparatus. A total of 260,000 cycles were carried out at 250 cycles/minute under a load of 5 N on samples immersed in toothpaste slurries. Surface roughness and Vickers microhardness were evaluated before and after toothbrushing. One sample of each material/toothpaste was analyzed by Scanning Electron Microscopy (SEM) and compared with a sample that had not been submitted to toothbrushing. Surface roughness increased significantly after toothbrushing, but no differences were noted after toothbrushing with different toothpastes. Toothbrushing did not significantly affect sample microhardness. The results suggest that toothpastes that contain and those that do not contain peroxides in their composition have different effects on cp Ti and Ti-5Ta surfaces. Although no significant difference was noted in the microhardness and roughness of the surfaces brushed with different toothpastes, both toothpastes increased roughness after toothbrushing.

  11. Surgical Revision after Sacroiliac Joint Fixation or Fusion

    Science.gov (United States)

    Holt, Timothy

    2017-01-01

    Background Minimally invasive sacroiliac joint (SIJ) fusion has been shown to be safe and effective for the treatment of SIJ dysfunction. Multiple devices are available to perform SIJ fixation or fusion. Surgical revision rates after these procedures have not been directly compared. Methods We retrospectively identified all patients in our practice who underwent SIJ fixation or fusion between 2003 and 2015. Using both chart review and focused contact with individual patients, we determined the likelihood of surgical revision. Revision rates were compared using Kaplan-Meier survival analysis. Results Thirty-eight patients underwent SIJ fixation with screws and 274 patients underwent SIJ fusion using triangular titanium implants. Four-year cumulative revision rates were 30.8% for fixation and 5.7% for fusion. Conclusions In our study, SIJ fixation with screws had a much higher revision rate compared to SIJ fusion with triangular titanium implants designed for bone adherence.

  12. Open Volumetric Mesh-An Efficient Data Structure for Tetrahedral and Hexa-hedral Meshes

    Institute of Scientific and Technical Information of China (English)

    XIAN Chu-hua; LI Gui-qing; GAO Shu-ming

    2013-01-01

    This work introduces a scalable and efficient topological structure for tetrahedral and hexahedral meshes. The design of the data structure aims at maximal flexibility and high performance. It provides a high scalability by using hierarchical representa-tions of topological elements. The proposed data structure is array-based, and it is a compact representation of the half-edge data structure for volume elements and half-face data structure for volumetric meshes. This guarantees constant access time to the neighbors of the topological elements. In addition, an open-source implementation named Open Volumetric Mesh (OVM) of the pro-posed data structure is written in C++using generic programming concepts.

  13. Computed tomographic measurements of mesh shrinkage after laparoscopic ventral incisional hernia repair with an expanded polytetrafluoroethylene mesh.

    Science.gov (United States)

    Schoenmaeckers, Ernst J P; van der Valk, Steef B A; van den Hout, Huib W; Raymakers, Johan F T J; Rakic, Srdjan

    2009-07-01

    The potential for shrinkage of intraperitoneally implanted meshes for laparoscopic repair of ventral and incisional hernia (LRVIH) remains a concern. Numerous experimental studies on this issue reported very inconsistent results. Expanded polytetrafluoroethylene (ePTFE) mesh has the unique property of being revealed by computed tomography (CT). We therefore conducted an analysis of CT findings in patients who had previously undergone LRVIH with an ePTFE mesh (DualMesh, WL Gore, Flagstaff, AZ, USA) in order to evaluate the shrinkage of implanted meshes. Of 656 LRVIH patients with DualMesh, all patients who subsequently underwent CT scanning were identified and only those with precisely known transverse diameter of implanted mesh and with CT scans made more than 3 months postoperatively were selected (n = 40). Two radiologists who were blinded to the size of the implanted mesh measured in consensus the maximal transverse diameter of the meshes by using the AquariusNET program (TeraRecon Inc., San Mateo, CA, USA). Mesh shrinkage was defined as the relative loss of transverse diameter as compared with the original transverse diameter of the mesh. The mean time from LRVIH to CT scan was 17.9 months (range 3-59 months). The mean shrinkage of the mesh was 7.5% (range 0-23.7%). For 11 patients (28%) there was no shrinkage at all. Shrinkage of 1-10% was found in 16 patients (40%), of 10-20% in 10 patients (25%), and of 20-24% in 3 patients (7.5%). No correlation was found regarding the elapsed time between LRVIH and CT, and shrinkage. There were two recurrences, one possibly related to shrinkage. Our observations indicate that shrinkage of DualMesh is remarkably lower than has been reported in experimental studies (8-51%). This study is the first to address the problem of shrinkage after intraperitoneal implantation of synthetic mesh in a clinical material.

  14. Nanodispersed boriding of titanium alloy

    Directory of Open Access Journals (Sweden)

    Kateryna O. Kostyk

    2015-12-01

    Full Text Available The problem of improving the operational reliability of machines is becoming increasingly important due to the increased mechanical, thermal and other loads on the details. There are many surface hardening methods for machines parts which breakdown begins with surface corruption. The most promising methods are chemo-thermal treatment. Aim: The aim of this work is to study the impact of boriding on the structure and properties of titanium alloy. Materials and Methods: The material of this study is VT3-1 titanium alloy. The boriding were conducted using nanodispersed powder blend based on boric substances. Results: It is established that boriding of paste compounds allows obtaining the surface hardness within 30...29 GPa and with declining to 27...26 GPa in layer to the transition zone (with total thickness up to 110 μm owing to changes of the layer phase composition where Ti2B, TiB, TiB2 titanium borides are formed. The increasing of chemical-thermal treatment time from 15 minutes to 2 hours leads to thickening of the borated layer (30...110 µm and transition zone (30...190 µm. Conclusions: Due to usage of nanodispersed boric powder, the boriding duration is decreasing in 2...3 times. This allows saving time and electric energy. The developed optimal mode of boriding the VT3-1 titanium alloy allows obtaining the required operational characteristics and to combine the saturation of the surface layer with atomic boron and hardening.

  15. Engineering Titanium for Improved Biological Response

    Energy Technology Data Exchange (ETDEWEB)

    Orme, C; Bearinger, J; Dimasi, E; Gilbert, J

    2002-01-23

    titanium dioxide surface atomic structure and the biological response at an implantation site. To date, most researchers in this area have surgically implanted materials into living organisms and then retrieved the implant after varying amounts of time have elapsed. The virtue of this style of experiment is that the full, correct chemistry of the body acts on the implant. The difficulty with these experiments is that it is then impossible to link cause with effect because too many variables are changing simultaneously. Another difficulty is that changes in the very early times are missed. The purpose of these experiments is to visualize the early time response of oxide films to electric fields and to solution variations found in the body near bone. Specifically these studies are meant to understand how chemical and electric stress affect the corrosion resistance and the formation of a biolayer. Instead of performing in vivo experiments as described above, our strategy uses titanium manufactured for implants and places these samples in controlled, simplified, solutions that mimic the electrolytic environment near the bone. We use an electrochemical atomic force microscope to image the real-time dynamics of the substrate in One of the most remarkable systems in the body is bone remodeling. Even in a purely natural solution as the oxide film is growing. While imaging we apply a potential between a reference electrode and the titanium substrate which creates a driving force for oxide growth and dissolution. We simultaneously collect the transient current that flows across the oxide layer and use step impedance polarization spectroscopy to determine electrical properties of the oxide layer. We will look for films that successfully nucleate the calcium phosphate crystals that comprise the inorganic phase of bone, but do not corrode under these challenging conditions. The goal is to correlate corrosion resistance and biolayer adhesion with oxide film morphology and material

  16. Artificial trachea reconstruction with two-stage approach using memory-alloy mesh

    Institute of Scientific and Technical Information of China (English)

    赵凤瑞; 张银合; 刘世民; 余建军

    2003-01-01

    @@ Artificial tracheal prosthesis is now a challenge to the entire surgical field all over the world. Previously, all kinds of prosthesis were "inner stent" that could not be integrated with native trachea. Since there is an interface between smooth surface of the prosthesis and living tissues, and the inner side of the prosthesis is not covered with living membrane, infections always happen around the prosthesis. We then developed a new technique, which combined memory-alloy mesh with traditional operative procedures. Memory-alloy mesh is extensible, flexible and can maintain the shape of a tube. It has very good compatibility with tissues and no antigenicity. Thus, it is the most desirable material nowadays that can be found to make the frame of an artificial trachea by using a two-stage approach. That is imbedding a pre-shaped memory-alloy mesh under skin or endothelium (pleura or peritoneum), and then making the "sandwich" pedicle skin and muscle flap to a pedicled artificial trachea anastomosed with native trachea. After a two-year experimental study, a patient received the artificial trachea replacement on April 18, 2002, with a good result.

  17. Micro-surgical endodontics.

    Science.gov (United States)

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

    2014-02-01

    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.

  18. Surgical innovation as sui generis surgical research.

    Science.gov (United States)

    Lotz, Mianna

    2013-12-01

    Successful innovative 'leaps' in surgical technique have the potential to contribute exponentially to surgical advancement, and thereby to improved health outcomes for patients. Such innovative leaps often occur relatively spontaneously, without substantial forethought, planning, or preparation. This feature of surgical innovation raises special challenges for ensuring sufficient evaluation and regulatory oversight of new interventions that have not been the subject of controlled investigatory exploration and review. It is this feature in particular that makes early-stage surgical innovation especially resistant to classification as 'research', with all of the attendant methodological and ethical obligations--of planning, regulation, monitoring, reporting, and publication--associated with such a classification. This paper proposes conceptual and ethical grounds for a restricted definition according to which innovation in surgical technique is classified as a form of sui generis surgical 'research', where the explicit goal of adopting such a definition is to bring about needed improvements in knowledge transfer and thereby benefit current and future patients.

  19. [Meta-Mesh: metagenomic data analysis system].

    Science.gov (United States)

    Su, Xiaoquan; Song, Baoxing; Wang, Xuetao; Ma, Xinle; Xu, Jian; Ning, Kang

    2014-01-01

    With the current accumulation of metagenome data, it is possible to build an integrated platform for processing of rigorously selected metagenomic samples (also referred as "metagenomic communities" here) of interests. Any metagenomic samples could then be searched against this database to find the most similar sample(s). However, on one hand, current databases with a large number of metagenomic samples mostly serve as data repositories but not well annotated database, and only offer few functions for analysis. On the other hand, the few available methods to measure the similarity of metagenomic data could only compare a few pre-defined set of metagenome. It has long been intriguing scientists to effectively calculate similarities between microbial communities in a large repository, to examine how similar these samples are and to find the correlation of the meta-information of these samples. In this work we propose a novel system, Meta-Mesh, which includes a metagenomic database and its companion analysis platform that could systematically and efficiently analyze, compare and search similar metagenomic samples. In the database part, we have collected more than 7 000 high quality and well annotated metagenomic samples from the public domain and in-house facilities. The analysis platform supplies a list of online tools which could accept metagenomic samples, build taxonomical annotations, compare sample in multiple angle, and then search for similar samples against its database by a fast indexing strategy and scoring function. We also used case studies of "database search for identification" and "samples clustering based on similarity matrix" using human-associated habitat samples to demonstrate the performance of Meta-Mesh in metagenomic analysis. Therefore, Meta-Mesh would serve as a database and data analysis system to quickly parse and identify similar

  20. Unbiased sampling and meshing of isosurfaces

    KAUST Repository

    Yan, Dongming

    2014-11-01

    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.

  1. Perspective on the Lagrange-Jacobi mesh

    Science.gov (United States)

    Rampho, Gaotsiwe J.

    2016-07-01

    This paper presents a unified treatment of the kinetic energy matrix elements related to a number of Lagrange functions associated with the Lagrange-Jacobi mesh. The matrix elements can be readily modified for application to problems requiring eigenfunction expansion with Lagrange-Legendre, Lagrange-Chebyshev, Lagrange-Gegenbauer, as well as the Lagrange-Jacobi functions. The applicability of and the accuracy attainable with the matrix elements is demonstrated with the solution to the Schrödinger equation for confining trigonometric Pöschl-Teller potentials. The results obtained are within machine accuracy when appropriate choices of the basis functions are used.

  2. Performance of FACTS equipment in Meshed systems

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-12-31

    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.

  3. Relativistic MHD with adaptive mesh refinement

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Matthew [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001 (United States); Hirschmann, Eric W [Department of Physics and Astronomy, Brigham Young University, Provo, UT 84602 (United States); Liebling, Steven L [Department of Physics, Long Island University-C W Post Campus, Brookville, NY 11548 (United States); Neilsen, David [Department of Physics and Astronomy, Brigham Young University, Provo, UT 84602 (United States)

    2006-11-22

    This paper presents a new computer code to solve the general relativistic magnetohydrodynamics (GRMHD) equations using distributed parallel adaptive mesh refinement (AMR). The fluid equations are solved using a finite difference convex ENO method (CENO) in 3 + 1 dimensions, and the AMR is Berger-Oliger. Hyperbolic divergence cleaning is used to control the {nabla} . B = 0 constraint. We present results from three flat space tests, and examine the accretion of a fluid onto a Schwarzschild black hole, reproducing the Michel solution. The AMR simulations substantially improve performance while reproducing the resolution equivalent unigrid simulation results. Finally, we discuss strong scaling results for parallel unigrid and AMR runs.

  4. SURGICAL TREATMENT OF PROGRESSIVE DYSPLASTIC COXARTROSIS IN CHILDREN (CLINICAL CASE

    Directory of Open Access Journals (Sweden)

    Иван Иванович Кужеливский

    2017-03-01

    Full Text Available Dysplastic coxarthrosis is dominate among children orthopedic cases, and its surgical alignment continues to be peracute. Despite the application of advanced therapies and medical treatment, the patients of surgical state case constitute a significant percentage of the total patient number, i. e. from 19 to 35 %. In this article a detailed literature review of surgical alignment methods for deficiency acetabular roof by applying different implants has been described. The authors have proposed applying titanium nickelide materials in the surgical alignment method, as such materials possess the following properties: high corrosion stability, full compatibility with the body tissues, as well as, sufficient porosis providing radial border structure regeneration of acetabular roof, which in its turn, improves the support ability of extermity. In the event of progression of coxarthrosis iliac segment is reserved for the upcoming replacement.

  5. Split Bregman's algorithm for three-dimensional mesh segmentation

    Science.gov (United States)

    Habiba, Nabi; Ali, Douik

    2016-05-01

    Variational methods have attracted a lot of attention in the literature, especially for image and mesh segmentation. The methods aim at minimizing the energy to optimize both edge and region detections. We propose a spectral mesh decomposition algorithm to obtain disjoint but meaningful regions of an input mesh. The related optimization problem is nonconvex, and it is very difficult to find a good approximation or global optimum, which represents a challenge in computer vision. We propose an alternating split Bregman algorithm for mesh segmentation, where we extended the image-dedicated model to a three-dimensional (3-D) mesh one. By applying our scheme to 3-D mesh segmentation, we obtain fast solvers that can outperform various conventional ones, such as graph-cut and primal dual methods. A consistent evaluation of the proposed method on various public domain 3-D databases for different metrics is elaborated, and a comparison with the state-of-the-art is performed.

  6. Embedding meshes in Boolean cubes by graph decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Ho, C.T. (IBM Almaden Research Center, San Jose, CA (US)); Johnsson, S.L. (Dept. of Computer Science and Electrical Engineering, Yale Univ., New Haven, CT (US))

    1990-04-01

    This paper explores the embeddings of multidimensional meshes into minimal Boolean cubes by graph decomposition. The graph decomposition technique can be used to improve the average dilation and average congestion. The graph decomposition technique combined with some particular two-dimensional embeddings allows for minimal-expansion, dilation-two, congestion-two embeddings of about 87% of all two-dimensional meshes, with a significantly lower average dilation and congestion than by modified line compression. For three-dimensional meshes the authors show that the graph decomposition technique, together with two three-dimensional mesh embeddings presented in this paper and modified line compression, yields dilation-two embeddings of more than 96% of all three dimensional meshes contained in a 512 {times} 512 {times} 512 mesh.

  7. Image-Based Geometric Modeling and Mesh Generation

    CERN Document Server

    2013-01-01

    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,...

  8. HypGrid2D. A 2-d mesh generator

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, N.N.

    1998-03-01

    The implementation of a hyperbolic mesh generation procedure, based on an equation for orthogonality and an equation for the cell face area is described. The method is fast, robust and gives meshes with good smoothness and orthogonality. The procedure is implemented in a program called HypGrid2D. The HypGrid2D program is capable of generating C-, O- and `H`-meshes for use in connection with the EllipSys2D Navier-Stokes solver. To illustrate the capabilities of the program, some test examples are shown. First a series of C-meshes are generated around a NACA-0012 airfoil. Secondly a series of O-meshes are generated around a NACA-65-418 airfoil. Finally `H`-meshes are generated over a Gaussian hill and a linear escarpment. (au)

  9. Investigation of Mesh Choosing Parameters in Screen Printing System

    Directory of Open Access Journals (Sweden)

    Ahmet AKGÜL

    2012-05-01

    Full Text Available 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, mesh variables examined in detail and optimum conditions indicated, with the aim of increase productivity, minimize to losses time, material and labor. As a result, this information’s for obtaining a high quality printing with screen-printing system have importance as a guide. Also resolution of the image, amount of print run and viscosity of the printing ink, factors affecting the selection of mesh.

  10. Randomised clinical trial: conventional Lichtenstein vs. hernioplasty with self-adhesive mesh in bilateral inguinal hernia surgery.

    Science.gov (United States)

    Porrero, Jose L; Castillo, María J; Pérez-Zapata, Ana; Alonso, María T; Cano-Valderrama, Oscar; Quirós, Esther; Villar, Sol; Ramos, Beatriz; Sánchez-Cabezudo, Carlos; Bonachia, Oscar; Marcos, Alberto; Pérez, Brígido

    2015-10-01

    To compare the results of conventional Lichtenstein hernioplasty with polypropylene mesh (PLP) with a lightweight self-adhesive mesh (Parietene Progrip®; Covidien, Dublin, Ireland) (PPG) used in patients with bilateral inguinal hernia. Randomised clinical trial with 89 patients with a minimum follow-up of 1 year. Every patient had bilateral inguinal hernia and had both prostheses implanted randomly, one on each side. Early postoperative and chronic pain was evaluated using the visual analogue scale. Also recurrence rate and subjective evaluation of patients were analysed. Pain in the early postoperative period was inferior on the side where the self-adhesive mesh had been implanted (6.12 vs. 6.62, p=0.005 during the 1st postoperative day; 2.12 vs. 2.62, p=0.001 during the 7th postoperative day). Differences disappeared with the long-term evaluation (0.71 vs. 0.98, p=0.148 1 year after the surgery). The operative time was significantly shorter on the PPG mesh side (24.37 ± 5.1 in case of the PPG mesh and 29.66 ± 5.6 in case of the PLP mesh, p<0,001). Recurrence occurred in seven patients (7.8%), six of them (6.7%, CI 3.0-14.4) on the PPG mesh side and one (1.1%, CI 0.2-7.8) on the PLP side. These differences were not statistically significant (p=0.125) CONCLUSIONS: Although hernioplasty with self-adhesive mesh reduced early postoperative pain, this reduction was clinically irrelevant and it had no influence on chronic pain. There was a trend towards a higher recurrence rate when self-adhesive meshes were used, and although in this study differences were not statistically significant they should be confirmed in later studies using larger samples. Surgical procedures that do not need fixing sutures are promising, but further studies are needed before they become the gold standard of inguinal hernia repair.

  11. 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)

    2016-06-21

    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.

  12. MeSH Up: effective MeSH text classification for improved document retrieval

    NARCIS (Netherlands)

    Trieschnigg, Dolf; Pezik, Piotr; Lee, Vivian; Jong, de Franciska; Kraaij, Wessel; Rebholz-Schuhmann, Dietrich

    2009-01-01

    Motivation: Controlled vocabularies such as the Medical Subject Headings (MeSH) thesaurus and the Gene Ontology (GO) provide an efficient way of accessing and organizing biomedical information by reducing the ambiguity inherent to free-text data. Different methods of automating the assignment of MeS

  13. MeSH Up: Effective MeSH text classification for improved document retrieval

    NARCIS (Netherlands)

    Trieschnigg, D.; Pezik, P.; Lee, V.; Jong, F.de; Kraaij, W.; Rebholz-Schuhmann, D.

    2009-01-01

    Motivation: Controlled vocabularies such as the Medical Subject Headings (MeSH) thesaurus and the Gene Ontology (GO) provide an efficient way of accessing and organizing biomedical information by reducing the ambiguity inherent to free-text data. Different methods of automating the assignment of MeS

  14. AUTOMATIC MESH GENERATION OF 3-D GEOMETRIC MODELS

    Institute of Scientific and Technical Information of China (English)

    刘剑飞

    2003-01-01

    In this paper the presentation of the ball-packing method is reviewed,and a scheme to generate mesh for complex 3-D geometric models is given,which consists of 4 steps:(1)create nodes in 3-D models by ball-packing method,(2)connect nodes to generate mesh by 3-D Delaunay triangulation,(3)retrieve the boundary of the model after Delaunay triangulation,(4)improve the mesh.

  15. Vertex-based diffusion for 3-D mesh denoising.

    Science.gov (United States)

    Zhang, Ying; Ben Hamza, A

    2007-04-01

    We present a vertex-based diffusion for 3-D mesh denoising by solving a nonlinear discrete partial differential equation. The core idea behind our proposed technique is to use geometric insight in helping construct an efficient and fast 3-D mesh smoothing strategy to fully preserve the geometric structure of the data. Illustrating experimental results demonstrate a much improved performance of the proposed approach in comparison with existing methods currently used in 3-D mesh smoothing.

  16. Multiphase Flow of Immiscible Fluids on Unstructured Moving Meshes

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...... 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....

  17. Automated quadrilateral mesh generation for digital image structures

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    With the development of advanced imaging technology, digital images are widely used. This paper proposes an automatic quadrilateral mesh generation algorithm for multi-colour imaged structures. It takes an original arbitrary digital image as an input for automatic quadrilateral mesh generation, this includes removing the noise, extracting and smoothing the boundary geometries between different colours, and automatic all-quad mesh generation with the above boundaries as constraints. An application example is...

  18. Hexahedral mesh generation via the dual arrangement of surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, S.A.; Tautges, T.J. [Sandia National Labs., Albuquerque, NM (United States)

    1997-12-31

    Given a general three-dimensional geometry with a prescribed quadrilateral surface mesh, the authors consider the problem of constructing a hexahedral mesh of the geometry whose boundary is exactly the prescribed surface mesh. Due to the specialized topology of hexahedra, this problem is more difficult than the analogous one for tetrahedra. Folklore has maintained that a surface mesh must have a constrained structure in order for there to exist a compatible hexahedral mesh. However, they have proof that a surface mesh need only satisfy mild parity conditions, depending on the topology of the three-dimensional geometry, for there to exist a compatible hexahedral mesh. The proof is based on the realization that a hexahedral mesh is dual to an arrangement of surfaces, and the quadrilateral surface mesh is dual to the arrangement of curves bounding these surfaces. The proof is constructive and they are currently developing an algorithm called Whisker Weaving (WW) that mirrors the proof steps. Given the bounding curves, WW builds the topological structure of an arrangement of surfaces having those curves as its boundary. WW progresses in an advancing front manner. Certain local rules are applied to avoid structures that lead to poor mesh quality. Also, after the arrangement is constructed, additional surfaces are inserted to separate features, so e.g., no two hexahedra share more than one quadrilateral face. The algorithm has generated meshes for certain non-trivial problems, but is currently unreliable. The authors are exploring strategies for consistently selecting which portion of the surface arrangement to advance based on the existence proof. This should lead us to a robust algorithm for arbitrary geometries and surface meshes.

  19. Increased chondrocyte adhesion on nanotubular anodized titanium.

    Science.gov (United States)

    Burns, Kevin; Yao, Chang; Webster, Thomas J

    2009-03-01

    Previous studies have demonstrated increased osteoblast (bone-forming cells) functions (including adhesion, synthesis of intracellular collagen, alkaline phosphatase activity, and deposition of calcium-containing minerals) on titanium anodized to possess nanometer features compared with their unanodized counterparts. Such titanium materials were anodized to possess novel nanotubes also capable of drug delivery. Since titanium has not only experienced wide spread commercial use in orthopedic but also in cartilage applications, the objective of the present in vitro study was for the first time to investigate chondrocyte (cartilage synthesizing cells) functions on titanium anodized to possess nanotubes. For this purpose, titanium was anodized in dilute hydrofluoric acid at 20 V for 20 min. Results showed increased chondrocyte adhesion on anodized titanium with nanotube structures compared with unanodized titanium. Importantly, the present study also provided evidence why. Since material characterization studies revealed significantly greater nanometer roughness and similar chemistry as well as crystallinity between nanotubular anodized and unanodized titanium, the results of the present study highlight the importance of the nanometer roughness provided by anodized nanotubes on titanium for enhancing chondrocyte adhesion. In this manner, the results of the present in vitro study indicated that anodization might be a promising quick and inexpensive method to modify the surface of titanium-based implants to induce better chondrocyte adhesion for cartilage applications.

  20. Biomimetic collagen/elastin meshes for ventral hernia repair in a rat model.

    Science.gov (United States)

    Minardi, Silvia; Taraballi, Francesca; Wang, Xin; Cabrera, Fernando J; Van Eps, Jeffrey L; Robbins, Andrew B; Sandri, Monica; Moreno, Michael R; Weiner, Bradley K; Tasciotti, Ennio

    2017-03-01

    E Sheets and Scaffolds) not only showed promising mechanical performance, but also allowed for an efficient neovascularization, resulting in new adipose and muscle tissue formation within the implant, in only 6weeks. In addition, our meshes allowed for the use of the same surgical procedure utilized in clinical practice, with the commercially available grafts. This study represents a significant step in the design of bioactive acellular off-the-shelf biomimetic meshes for ventral hernia repair. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Finding Regions of Interest on Toroidal Meshes

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Kesheng; Sinha, Rishi R; Jones, Chad; Ethier, Stephane; Klasky, Scott; Ma, Kwan-Liu; Shoshani, Arie; Winslett, Marianne

    2011-02-09

    Fusion promises to provide clean and safe energy, and a considerable amount of research effort is underway to turn this aspiration intoreality. This work focuses on a building block for analyzing data produced from the simulation of microturbulence in magnetic confinementfusion devices: the task of efficiently extracting regions of interest. Like many other simulations where a large amount of data are produced,the careful study of ``interesting'' parts of the data is critical to gain understanding. In this paper, we present an efficient approach forfinding these regions of interest. Our approach takes full advantage of the underlying mesh structure in magnetic coordinates to produce acompact representation of the mesh points inside the regions and an efficient connected component labeling algorithm for constructingregions from points. This approach scales linearly with the surface area of the regions of interest instead of the volume as shown with bothcomputational complexity analysis and experimental measurements. Furthermore, this new approach is 100s of times faster than a recentlypublished method based on Cartesian coordinates.

  2. GRChombo : Numerical Relativity with Adaptive Mesh Refinement

    CERN Document Server

    Clough, Katy; Finkel, Hal; Kunesch, Markus; Lim, Eugene A; Tunyasuvunakool, Saran

    2015-01-01

    Numerical relativity has undergone a revolution in the past decade. With a well-understood mathematical formalism, and full control over the gauge modes, it is now entering an era in which the science can be properly explored. In this work, we introduce GRChombo, a new numerical relativity code written to take full advantage of modern parallel computing techniques. GRChombo's features include full adaptive mesh refinement with block structured Berger-Rigoutsos grid generation which supports non-trivial "many-boxes-in-many-boxes" meshing hierarchies, and massive parallelism through the Message Passing Interface (MPI). GRChombo evolves the Einstein equation with the standard BSSN formalism, with an option to turn on CCZ4 constraint damping if required. We show that GRChombo passes all the standard "Apples-to-Apples" code comparison tests. We also show that it can stably and accurately evolve vacuum black hole spacetimes such as binary black hole mergers, and non-vacuum spacetimes such as scalar collapses into b...

  3. The Tera Multithreaded Architecture and Unstructured Meshes

    Science.gov (United States)

    Bokhari, Shahid H.; Mavriplis, Dimitri J.

    1998-01-01

    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.

  4. Mesh-based parallel code coupling interface

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, K.; Steckel, B. (eds.) [GMD - Forschungszentrum Informationstechnik GmbH, St. Augustin (DE). Inst. fuer Algorithmen und Wissenschaftliches Rechnen (SCAI)

    2001-04-01

    MpCCI (mesh-based parallel code coupling interface) is an interface for multidisciplinary simulations. It provides industrial end-users as well as commercial code-owners with the facility to combine different simulation tools in one environment. Thereby new solutions for multidisciplinary problems will be created. This opens new application dimensions for existent simulation tools. This Book of Abstracts gives a short overview about ongoing activities in industry and research - all presented at the 2{sup nd} MpCCI User Forum in February 2001 at GMD Sankt Augustin. (orig.) [German] MpCCI (mesh-based parallel code coupling interface) definiert eine Schnittstelle fuer multidisziplinaere Simulationsanwendungen. Sowohl industriellen Anwender als auch kommerziellen Softwarehersteller wird mit MpCCI die Moeglichkeit gegeben, Simulationswerkzeuge unterschiedlicher Disziplinen miteinander zu koppeln. Dadurch entstehen neue Loesungen fuer multidisziplinaere Problemstellungen und fuer etablierte Simulationswerkzeuge ergeben sich neue Anwendungsfelder. Dieses Book of Abstracts bietet einen Ueberblick ueber zur Zeit laufende Arbeiten in der Industrie und in der Forschung, praesentiert auf dem 2{sup nd} MpCCI User Forum im Februar 2001 an der GMD Sankt Augustin. (orig.)

  5. Feature detection of triangular meshes vianeighbor supporting

    Institute of Scientific and Technical Information of China (English)

    Xiao-chao WANG; Jun-jie CAO; Xiu-ping LIU; Bao-jun LI; Xi-quan SHI; Yi-zhen SUN

    2012-01-01

    We propose a robust method for detecting features on triangular meshes by combining normal tensor voting with neighbor supporting.Our method contains two stages:feature detection and feature refinement.First,the normal tensor voting method is modified to detect the initial features,which may include some pseudo features.Then,at the feature refinement stage,a novel salient measure deriving from the idea of neighbor supporting is developed. Benefiting from the integrated reliable salient measure feature,pseudo features can be effectively discriminated from the initially detected features and removed. Compared to previous methods based on the differential geometric property,the main advantage of our method is that it can detect both sharp and weak features.Numerical experiments show that our algorithm is robust,effective,and can produce more accurate results.We also discuss how detected features are incorporated into applications,such as feature-preserving mesh denoising and hole-filling,and present visually appealing results by integrating feature information.

  6. An Evaluation Method for Distortion Energy Parameterization of Triangular Meshes

    Institute of Scientific and Technical Information of China (English)

    SHI Jing; ZHAO Xiu-yang; ZHANG Cai-ming; YANG Bo

    2013-01-01

    Parameterization of triangle meshes is a fundamental problem for texture mapping, surface fitting, surface reconstruction, and mesh editing. The deformation of triangular meshes caused by the parameterized process is the measurement of parameterization. Traditional standard method has its limitation when evaluating mixture distortion energy parameterizations. Thus an evaluation method bases on distortion energy parameterization of triangular meshes is introduced for the limitation. The novel method employs an adaptive expression form to the mixture energy, and uses a weight factor to represent distortion energy distribution. By using this method, we can evaluate all kinds of parameterization in a uniform measurement and acquire a more intuitive and clear evaluation.

  7. Numerical modeling of seismic waves using frequency-adaptive meshes

    Science.gov (United States)

    Hu, Jinyin; Jia, Xiaofeng

    2016-08-01

    An improved modeling algorithm using frequency-adaptive meshes is applied to meet the computational requirements of all seismic frequency components. It automatically adopts coarse meshes for low-frequency computations and fine meshes for high-frequency computations. The grid intervals are adaptively calculated based on a smooth inversely proportional function of grid size with respect to the frequency. In regular grid-based methods, the uniform mesh or non-uniform mesh is used for frequency-domain wave propagators and it is fixed for all frequencies. A too coarse mesh results in inaccurate high-frequency wavefields and unacceptable numerical dispersion; on the other hand, an overly fine mesh may cause storage and computational overburdens as well as invalid propagation angles of low-frequency wavefields. Experiments on the Padé generalized screen propagator indicate that the Adaptive mesh effectively solves these drawbacks of regular fixed-mesh methods, thus accurately computing the wavefield and its propagation angle in a wide frequency band. Several synthetic examples also demonstrate its feasibility for seismic modeling and migration.

  8. Dimensionality Reduction of Laplacian Embedding for 3D Mesh Reconstruction

    Science.gov (United States)

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

    2016-06-01

    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.

  9. A New Approach to Fully Automatic Mesh Generation

    Institute of Scientific and Technical Information of China (English)

    闵卫东; 张征明; 等

    1995-01-01

    Automatic mesh generation is one of the most important parts in CIMS (Computer Integrated Manufacturing System).A method based on mesh grading propagation which automatically produces a triangular mesh in a multiply connected planar region is presented in this paper.The method decomposes the planar region into convex subregions,using algorithms which run in linear time.For every subregion,an algorithm is used to generate shrinking polygons according to boundary gradings and form delaunay triangulation between two adjacent shrinking polygons,both in linear time.It automatically propagates boundary gradings into the interior of the region and produces satisfactory quasi-uniform mesh.

  10. Biology of biological meshes used in hernia repair.

    Science.gov (United States)

    Novitsky, Yuri W

    2013-10-01

    Successful repair of most hernias requires the use of a prosthetic implant for reinforcement of the defect. Because of the need for prosthetic implants to resist infections as well to support repairs in contaminated or potentially contaminated fields, biological meshes have been developed to take the place of nondegradable synthetic meshes in cases where mesh infection is of high concern. The ideal is a biological matrix that resists infection while providing durable reinforcement of a hernia repair. This article reviews the validity of assumptions that support the purported notion of the biological behavior of biological meshes.

  11. Triangulated manifold meshing method preserving molecular surface topology.

    Science.gov (United States)

    Chen, Minxin; Tu, Bin; Lu, Benzhuo

    2012-09-01

    Generation of manifold mesh is an urgent issue in mathematical simulations of biomolecule using boundary element methods (BEM) or finite element method (FEM). Defects, such as not closed mesh, intersection of elements and missing of small structures, exist in surface meshes generated by most of the current meshing method. Usually the molecular surface meshes produced by existing methods need to be revised carefully by third party software to ensure the surface represents a continuous manifold before being used in a BEM and FEM calculations. Based on the trace technique proposed in our previous work, in this paper, we present an improved meshing method to avoid intersections and preserve the topology of the molecular Gaussian surface. The new method divides the whole Gaussian surface into single valued pieces along each of x, y, z directions by tracing the extreme points along the fold curves on the surface. Numerical test results show that the surface meshes produced by the new method are manifolds and preserve surface topologies. The result surface mesh can also be directly used in surface conforming volume mesh generation for FEM type simulation. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Construction of Nanophase Novel Coatings-Based Titanium for the Enhancement of Protein Adsorption

    Institute of Scientific and Technical Information of China (English)

    Sahar A.Fadlallah; Mohammed A.Amin; Ghaida S.Alosaimi

    2016-01-01

    In the recent years,biological nanostructures coatings have been incorporated into orthopedic and dental implants in order to accelerate osseointegration and reducing surgical restrictions.In the present work,chemical etching,anodization and metal doping surface modification methods were integrated in one strategy to fabricate innovative titanium surfaces denominated by titanium nanoporous,anodized titanium nanoporous,silver-anodized titanium nanoporous and gold-anodized titanium nanoporous.The stability properties of nanostructures-coated surfaces were elucidated using electrochemical impedance spectroscopy (EIS) after 7 days of immersion in simulated biological fluids.Morphology and chemical compositions of new surfaces were characterized by scanning electron microscope and energy-dispersive X-ray analysis.The EIS results and data fitting to the electrical equivalent circuit model demonstrated the influence of adsorption of bovine serum albumin on new surfaces as a function of protein concentration.Adsorption process was described by the very well-known model of the Langrnuir adsorption isotherm.The thermodynamic parameter △GADs (-50 to 59 kJ mol-1) is calculated,which supports the instantaneous adsorption of protein from biological fluids to new surfaces and refers to their good biocompatibility.Ultimately,this study explores new surface strategy to gain new implants as a means of improving clinical outcomes of patients undergoing orthopedic surgery.

  13. [Morphology of tissue reactions around implants after combined surgical repair of the abdominal wall].

    Science.gov (United States)

    Vostrikov, O V; Zotov, V A; Nikitenko, E V

    2004-01-01

    Tissue reactions to titanium-nickelide and polypropylen and caprone implants used in surgical treatment of anterior aldomen wall hernias were studied in experiment. Digital density of leukocytes, fibroblasts, vessels, thickness of the capsule were studied. Pronounced inflammatory reaction was observed on day 3 which attenuated on day 14 in case of titanium nickelide and on day 30-60 in case of polypropylene and caprone. Fibroplastic processes start in the first group after 7 days while in the second group only after 30 days of the experiment. Thickness of the capsule around titanium-nickelide was 2-3 times less than around polypropylene and caprone. Thus, titanium-nickelide material is biologically more inert than caprone and polypropylen which are widely used in surgery of hernias.

  14. Surgical treatment of extensive complex odontoma in the mandible by corticotomy. A case report.

    Science.gov (United States)

    Nogueira, A S; Gonçales, E S; Gonçales, A G B; Thiegui-Neto, V; Nogueira, C B P; Nogueira, A; Medeiros, R

    2013-09-01

    Odontomas represent the most prevalent odontogenic tumors in the jaw. The treatment of choice is surgical removal, usually performed by conventional techniques involving ostectomies to expose the tumor. In this paper, the authors describe, through the report of a case of complex odontoma located in the mandibular angle, a more conservative surgical technique called corticotomy, in which the bone removed for access to the tumor (buccal cortical) is repositioned and fixed by titanium plates of 1.5 mm.

  15. The effect of music on robot-assisted laparoscopic surgical performance.

    Science.gov (United States)

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

    2010-12-01

    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.

  16. Advanced 3D mesh manipulation in stereolithographic files and post-print processing for the manufacturing of patient-specific vascular flow phantoms

    Science.gov (United States)

    O'Hara, Ryan P.; Chand, Arpita; Vidiyala, Sowmya; Arechavala, Stacie M.; Mitsouras, Dimitrios; Rudin, Stephen; Ionita, Ciprian N.

    2016-03-01

    Complex vascular anatomies can cause the failure of image-guided endovascular procedures. 3D printed patient-specific vascular phantoms provide clinicians and medical device companies the ability to preemptively plan surgical treatments, test the likelihood of device success, and determine potential operative setbacks. This research aims to present advanced mesh manipulation techniques of stereolithographic (STL) files segmented from medical imaging and post-print surface optimization to match physiological vascular flow resistance. For phantom design, we developed three mesh manipulation techniques. The first method allows outlet 3D mesh manipulations to merge superfluous vessels into a single junction, decreasing the number of flow outlets and making it feasible to include smaller vessels. Next we introduced Boolean operations to eliminate the need to manually merge mesh layers and eliminate errors of mesh self-intersections that previously occurred. Finally we optimize support addition to preserve the patient anatomical geometry. For post-print surface optimization, we investigated various solutions and methods to remove support material and smooth the inner vessel surface. Solutions of chloroform, alcohol and sodium hydroxide were used to process various phantoms and hydraulic resistance was measured and compared with values reported in literature. The newly mesh manipulation methods decrease the phantom design time by 30 - 80% and allow for rapid development of accurate vascular models. We have created 3D printed vascular models with vessel diameters less than 0.5 mm. The methods presented in this work could lead to shorter design time for patient specific phantoms and better physiological simulations.

  17. Antimicrobial titanium/silver PVD coatings on titanium

    Directory of Open Access Journals (Sweden)

    Thull Roger

    2006-03-01

    Full Text Available Abstract Background Biofilm formation and deep infection of endoprostheses is a recurrent complication in implant surgery. Post-operative infections may be overcome by adjusting antimicrobial properties of the implant surface prior to implantation. In this work we described the development of an antimicrobial titanium/silver hard coating via the physical vapor deposition (PVD process. Methods Coatings with a thickness of approximately 2 μm were deposited on titanium surfaces by simultaneous vaporisation of both metals in an inert argon atmosphere with a silver content of approximately 0.7 – 9% as indicated by energy dispersive X-ray analysis. On these surfaces microorganisms and eukaryotic culture cells were grown. Results The coatings released sufficient silver ions (0.5–2.3 ppb when immersed in PBS and showed significant antimicrobial potency against Staphylococcus epidermis and Klebsiella pneumoniae strains. At the same time, no cytotoxic effects of the coatings on osteoblast and epithelial cells were found. Conclusion Due to similar mechanical performance when compared to pure titanium, the TiAg coatings should be suitable to provide antimicrobial activity on load-bearing implant surfaces.

  18. Hydrogen content in titanium and a titanium-zirconium alloy after acid etching.

    Science.gov (United States)

    Frank, Matthias J; Walter, Martin S; Lyngstadaas, S Petter; Wintermantel, Erich; Haugen, Håvard J

    2013-04-01

    Dental implant alloys made from titanium and zirconium are known for their high mechanical strength, fracture toughness and corrosion resistance in comparison with commercially pure titanium. The aim of the study was to investigate possible differences in the surface chemistry and/or surface topography of titanium and titanium-zirconium surfaces after sand blasting and acid etching. The two surfaces were compared by X-ray photoelectron spectroscopy, secondary ion mass spectroscopy, scanning electron microscopy and profilometry. The 1.9 times greater surface hydrogen concentration of titanium zirconium compared to titanium was found to be the major difference between the two materials. Zirconium appeared to enhance hydride formation on titanium alloys when etched in acid. Surface topography revealed significant differences on the micro and nanoscale. Surface roughness was increased significantly (pzirconium alloy. High-resolution images showed nanostructures only present on titanium zirconium.

  19. Significant improvement of biocompatibility of polypropylene mesh for incisional hernia repair by using poly-ε-caprolactone nanofibers functionalized with thrombocyte-rich solution

    Directory of Open Access Journals (Sweden)

    Plencner M

    2015-04-01

    Full Text Available Martin Plencner,1,2 Eva Prosecká,1,2 Michala Rampichová,2,3 Barbora East,4 Matej Buzgo,2,3 Lucie Vysloužilová,3 Jiří Hoch,4 Evžen Amler1,2,5 1Institute of Biophysics, 2nd Faculty of Medicine, Charles University in Prague, Prague, 2Laboratory of Tissue Engineering, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, 3University Center for Energy Efficient Buildings (UCEEB, The Czech Technical University in Prague, Bustehrad, 4Department of Surgery, 2nd Faculty of Medicine, Charles University in Prague, Prague, 5Faculty of Biomedical Engineering, Czech Technical University in Prague, Kladno, Czech Republic Abstract: 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

  20. 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.

    2013-09-30

    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.