Search results for "COMPRESSION"
showing 10 items of 774 documents
Stress distribution in fixed mandibular prostheses fabricated by CAD/CAM and conventional techniques: Photoelastic and strain gauge analyses
2019
Made available in DSpace on 2020-12-12T00:55:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-09-01 The aim of this study was to evaluate the distribution of stress in complete fixed mandibular prostheses with infrastructures (IE) fabricated with different materials and techniques, under compressive force. A model of an edentulous mandible, which received five 4x11 mm external hexagon implants between the mental foramens, was fabricated. The groups were divided into: Group I - IE in nickel-chromium with an acrylic resin occlusal coating; Group II - IE in nickel-chromium with a ceramic occlusal coating; Group III - IE milled in zirconia with a ceramic coating. For the photoelastic m…
Analysis of stress distribution in ceramic and titanium implants in alveolar sockets of the anterior region of the maxilla
2019
Background In the routine of dentistry, knowing the biomechanical properties of implant systems and their inherent stress distribution under force loading is an essential step to predict structural damage and biological responses. This study aimed to investigate stress distribution in zirconia and titanium implants and their biomechanical response in alveolar sockets of the anterior region of the maxilla through tridimensional finite element analysis. Material and Methods From computed tomography scans of a reference patient, three models of the maxillary dental arch were designed with Rhinoceros 5.0 software (McNeel Europe™, Barcelona, Spain). In each model, a dental implant replaced the m…
Intramedullary nailing vs. palmar locked plating for unstable dorsally comminuted distal radius fractures: A biomechanical study
2010
Abstract Background The purpose of this study was to compare the stability of a 2.4 mm palmar locking compression plate and a new intramedullary nail-plate-hybrid Targon DR for dorsally comminuted distal radius fractures. Methods An extraarticular 10 mm dorsally open wedge osteotomy was created in 8 pairs of fresh frozen human radii to simulate an AO–A3-fracture. The fractures were stabilized using one of the fixation methods. The specimens were loaded axially with 200 N and dorsal-excentrically with 80 N. 2000 cycles of dynamic loading and axial loading-to-failure were performed. Findings Axial loading revealed that intramedullary osteosynthesis (Targon DR: 369 N/mm) was significantly ( p …
A coupled lossy local-mode theory description of a plasmonic tip
2012
International audience; We investigate power propagation in a metal-coated tapered optical fiber. We analyze in detail the conversion from the fiber core guided mode to a surface plasmon polariton (SPP) confined at the tip apex. To this aim, we adapt coupled local-mode theory to include lossy modes. Two distinct regimes are identified. In the case of thin metal coating, a strong coupling regime occurs between a core guided mode and a SPP with good conversion efficiency. In the case of thick metal coating, a very weak coupling occurs. Finally, energy confinement and the role of Joule losses are discussed in the near-infrared and visible ranges. Moreover, the coupled equations derived for loc…
Characterisation of Mesozoic–Cenozoic deformations and palaeostress fields in the Central Constantinois, northeast Algeria
1998
Abstract Tectonic analysis in conjunction with the microtectonic study of Mesozoic–Cenozoic series of the Central Constantinois of Algeria are used to reconstruct the sequence of tectonic phases since Cretaceous times. The retrotectonic method used to marshal the microtectonic data makes it possible to distinguish deformations related to Mesozoic tectonic phases from those associated with Cenozoic pre- and post-thrust sheet phases. A N120°E extensional and a N180°E compressional phase are highlighted in Albian–Cenomanian and latest Maastrichtian times, respectively. The Cenozoic era is marked by a series of three compressional phases oriented N90°–120°E in the Late Eocene, and N20°–30°E and…
Drawing and extruding: Theoretical and approximate formulas
1969
The problem of drawing of wires and of strips has been treated in several studies; among these the studies of Sachs seem essential. However, the results deduced according to similar theories are not always in accordance with the experimental results: reduction of area or of thickness are in fact usually smaller than those resulting from the theory. This is in dependance of the fact that Sachs has adopted the Limiting Condition of Yielding by v. Mises, according to which the limit values of stress in traction and compression are equal. More recently other AA. (Alberti, Noto La Diega, Bugini), admitting the Limiting Condition of Yielding by A. (or of the Paraboloid of Revolution) of which we …
Sinusitis in Thyroid Associated Ophthalmopathy
1993
In 19 patients with thyroid associated ophthalmopathy undergoing orbital decompression, histologic examination of paranasal sinus mucosa revealed moderate to severe inflammatory alterations in all patients. Only 2/19 patients had a history of chronic sinusitis. In 4/19 patients, mucosal abnormalities of the paranasal sinuses were found on preoperative computed tomography CT scans. Postoperatively, 10/19 patients developed purulent sinusitis. It is suggested that patients suffering from thyroid associated ophthalmopathy have an increased incidence of histologically detectable inflammatory changes of paranasal sinus mucosa. Because of preexisting mucosal inflammation, these patients are pron…
GeV-scale neutrinos: interactions with mesons and DUNE sensitivity
2021
The simplest extension of the SM to account for the observed neutrino masses and mixings is the addition of at least two singlet fermions (or right-handed neutrinos). If their masses lie at or below the GeV scale, such new fermions would be produced in meson decays. Similarly, provided they are sufficiently heavy, their decay channels may involve mesons in the final state. Although the couplings between mesons and heavy neutrinos have been computed previously, significant discrepancies can be found in the literature. The aim of this paper is to clarify such discrepancies and provide consistent expressions for all relevant effective operators involving mesons with masses up to 2 GeV. Moreove…
Female New-Born with Undifferentiated Sarcoma Defined by Bcor-Ccnb3 Fusion Transcript
2015
A female new-born presented with a sacrococcygeal mass with spinal cord compression. A preliminary histologic diagnosis determined a small round blue cell tumor and immunohistochemical results discarded neuroblastoma, rhabdomyosarcoma, rhabdoid tumor, Ewing or peripheral neuroectodermal tumor (PNET). The results obtained by SNPa showed a chromosome Xp11.4 deletion of 0.9 Mb, where the BCOR gene is located. RT-PCR did not detect the ETV6-NTRK3 or EWSR1-FLI1 fusion, but did reveal the presence of the BCOR-CCNB3 fusion transcript, recently reported in some undifferentiated sarcomas, establishing the diagnosis of “Ewing-like” sarcoma. Analysis of CCNB3 expression by immunohistochemistry showed …
A CASE OF CARDIAC COMPRESSION BY HEPATIC CYST IN A WOMAN WITH POLYCYSTIC KIDNEY DISEASE.
2008
Liver cysts are common extrarenal manifestations of autosomal dominant polycystic kidney disease (ADPKD). They occur more frequently in women, and are also more in number and larger in size, than in men. Liver cysts tend to develop slower than the kidney cysts; their number and size increases with the age (worsening kidney function), number of pregnancies, and estrogen assumption. Although most patients with ADPKD report no liver symptoms, sometimes, chronic manifestations related to progressive increase of the polycystic liver are experienced. The quality of life can be severely impaired with huge hepatomegaly causing abdominal distension, pain, dyspepsia, dyspnoea, fatigue, physical and e…