1000 resultados para Reconstruction tridimensionnelle


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The Lagoa Dourada is a circular-shaped pond formed on the Furnas Formation (Devonian of the Paraná Basin), filled by late Pleistocene - Holocene sediments. It lies in the hydrographic basin of the Guabiroba River, a tributary of the Tibagi River situated in the Campos Gerais region of the State of Paraná, southern Brazil. The pond is about 200 m in diameter and the maximum water depth is 5.4 m. Geological, chemical, textural and mineralogical studies on a core sample of the sediments collected from the Lagoa Dourada, 12.2 m thick, was obtained for investigations of paleoenvironmental changes as well as to provide additional data to support previous reconstructions based on palynomorphs and diatoms. Within the period recorded in the core, the pond has been filled by sandy material introduced by springs at the northern edge of the pond as well as by muddy material brought in by floodwaters of the Guabiroba River. Thus, the sandy layers could be interpreted as evidence of drier climates with consequent diminution of fluvial overflow, but with maintenance of the sandy deposits coming from springs. The occurrence of euhedral pyrite in the sediments, locally associated with gypsum, may indicate periods of increase in the organic matter content or an increase in the water salinity, what could be related to greater evaporation under drier paleoclimate regimes. Three cycles defined by an increase in the total carbon content of the sediments of the pond were observed. These cycles seem to correspond to an increase in the isotope ratio 13C/12C (δ13C). Several hypotheses can be suggested to explain the presence of these cycles, including the alternation of wetter or drier climatic phases. The convergence of the sedimentological data obtained during this study with previous microfossil paleoclimatic (pollens and diatoms) indicators and radiocarbon dating suggests that a drier paleoclimatic phase occurred around 8720±150 years B.P. The evidence for a second drier phase in more recent times is less consistent. This subsequent phase could correspond to the drier phase in southern and southeastern Brazil between 5000 and 3000 years B.P. as suggested by other paleoclimatic studies.

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Purpose: Interposition of a jejunal tube between the common bile duct and duodenum. Methods: Five adult mongrel dogs of both sexes, weighing on average 22.3 kg (18 to 26.5 kg), were used. Obstructive jaundice was induced by ligation of the distal common bile duct. After one week, a 2.5-cm long jejunal tube was fabricated from a segment of the loop removed 15 cm from the Treitz angle and interposed between the common bile duct and duodenum. Results: The animals presented good clinical evolution and no complications were observed. After 6 weeks, complete integration was noted between the bile duct mucosa, tube and duodenum and a significant reduction in total bilirubin and alkaline phosphatase was observed when compared to the values obtained one week after ligation of the common bile duct. Conclusion: The jejunal tube interposed between the dilated bile duct and duodenum showed good anatomic integration and reduced total bilirubin and alkaline phosphatase levels in the animals studied.

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Purpose: Bone maintenance after mandibular reconstruction with autogenous iliac crest may be disappointing due to extensive resorption in the long term. The potential of the guided-bone regeneration (GBR) technique to enhance the healing process in segmental defects lacks comprehensive scientific documentation. This study aimed to investigate the influence of polylactide membrane permeability on the fate of iliac bone graft (BG) used to treat mandibular segmental defects. Materials and Methods: Unilateral 10-mm-wide segmental defects were created through the mandibles of 34 mongrel dogs. All defects were mechanically stabilized, and the animals were divided into 6 treatment groups: control, BG alone, microporous membrane (poly L/DL-lactide 80/20%) (Mi); Mi plus BG; microporous laser-perforated (15 cm2 ratio) membrane (Mip), and Mip plus BG. Calcein fluorochrome was injected intravenously at 3 months, and animal euthanasia was carried out at 6 months postoperatively. Results: Histomorphometry showed that BG protected by Mip was consistently related to larger amounts of bone compared with other groups (P ≤ .0001). No difference was found between defects treated with Mip alone and BG alone. Mi alone rendered the least bone area and reduced the amount of grafted bone to control levels. Data from bone labeling indicated that the bone formation process was incipient in the BG group at 3 months postoperatively regardless of whether or not it was covered by membrane. In contrast, GBR with Mip tended to enhance bone formation activity at 3 months. Conclusions: The use of Mip alone could be a useful alternative to BG. The combination of Mip membrane and BG efficiently delivered increased bone amounts in segmental defects compared with other treatment modalities. © 2008 American Association of Oral and Maxillofacial Surgeons.

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The resolution and the linearity of time measurements made with the CMS electromagnetic calorimeter are studied with samples of data from test beam electrons, cosmic rays, and beam-produced muons. The resulting time resolution measured by lead tungstate crystals is better than 100 ps for energy deposits larger than 10 GeV. Crystal-to-crystal synchronization with a precision of 500 ps is performed using muons produced with the first LHC beams in 2008. © 2010 IOP Publishing Ltd and SISSA.

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The performance of muon reconstruction in CMS is evaluated using a large data sample of cosmic-ray muons recorded in 2008. Efficiencies of various high-level trigger, identification, and reconstruction algorithms have been measured for a broad range of muon momenta, and were found to be in good agreement with expectations from Monte Carlo simulation. The relative momentum resolution for muons crossing the barrel part of the detector is better than 1% at 10 GeV/c and is about 8% at 500 GeV/c, the latter being only a factor of two worse than expected with ideal alignment conditions. Muon charge misassignment ranges from less than 0.01% at 10GeV/c to about 1% at 500 GeV/c. © 2010 IOP Publishing Ltd and SISSA.

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The following is a clinical case report of a patient whose chief complaint was the presence of generalized spacing in the maxillary anterior segment following orthodontic treatment. After meticulous clinical analyses and discussions of the clinical procedures to be adopted, dental bleaching was performed in both arches with 10% hydrogen peroxide (Opalescence Trèswhite Supreme 10% Hydrogen Peroxide - Ultradent Products, Inc., South Jordan, USA) after the conclusion and stabilization of orthodontic treatment. Then, the orthodontic appliance was removed and the diastemas in the maxillary anterior teeth were closed with Amelogen Plus (Ultradent Products, Inc., South Jordan, USA) resin composite. It was observed that the association of orthodontic, bleaching, and restorative procedures was capable of restoring dental shape, function, and esthetics, allowing the patient to smile without hesitation.

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The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 pb-1 of data collected in pp collisions at s = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV/c is above 95% over the whole region of pseudorapidity covered by the CMS muon system, < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeVc is higher than 90% over the full η range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100GeV/c and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV/c. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation. © 2012 IOP Publishing Ltd and Sissa Medialab srl.

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Atrophic mandible fractures are frequently a challenge to stabilize. This study evaluated, through mechanical testing in vitro, the number of locking screws that is sufficient to withstand loading when applied with a locking reconstruction plate in the fixation of atrophic mandible fractures. Polyurethane mandibles with a simulated linear fracture at the midline were used as substratum. Results show that resistance of the fixation is poor when one and two screws are used on each side of the fracture. Three screws on each side of the fracture significantly increases the resistance to displacement. However, no additional strength is added to the construct when more than three screws per side are used. © 2013 International Association of Oral and Maxillofacial Surgeons.

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Background: In the international scientific literature, there are few studies that emphasize the presence or absence of hair in forensic facial reconstructions. There are neither Brazilian studies concerning digital facial reconstructions without hair, nor research comparing recognition tests between digital facial reconstructions with hair and without hair. The miscegenation of Brazilian people is considerable. Brazilian people, and, in particular, Brazilian women, even if considered as Caucasoid, may present the hair in very different ways: curly, wavy or straight, blonde, red, brown or black, long or short, etc. For this reason, it is difficult to find a correct type of hair for facial reconstruction (unless, in real cases, some hair is recovered with the skeletal remains). Aims and methods: This study focuses on the performance of three different digital forensic facial reconstructions, without hair, of a Brazilian female subject (based on one international database and two Brazilian databases for soft facial-tissue thickness) and evaluates the digital forensic facial reconstructions comparing them to photographs of the target individual and nine other subjects, employing the recognition method. A total of 22 assessors participated in the recognition process; all of them were familiar with the 10 individuals who composed the face pool. Results and conclusions: The target subject was correctly recognized by 41% of the 22 examiners in the International Pattern, by 32% in the Brazilian Magnetic Resonance Pattern and by 32% in the Brazilian Fresh Cadavers Pattern. The facial reconstructions without hair were correctly recognized using the three databases of facial soft-tissue thickness. The observed results were higher than the results obtained using facial reconstructions with hair, from the same skull, which can indicate that it is better to not use hair, at least when there is no information concerning its characteristics. © 2013 Elsevier B.V. All rights reserved.

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Background: Cardiovascular diseases remain leaders as the major causes of mortality in Western society. Restoration of the circulation through construction of bypass surgical treatment is regarded as the gold standard treatment of peripheral vascular diseases, and grafts are necessary for this purpose. The great saphenous vein is often not available and synthetic grafts have their limitations. Therefore, new techniques to produce alternative grafts have been developed and, in this sense, tissue engineering is a promising alternative to provide biocompatible grafts. This study objective was to reconstruct the endothelium layer of decellularized vein scaffolds, using mesenchymal stem cells (MSCs) and growth factors obtained from platelets. Methods: Fifteen nonpregnant female adult rabbits were used for all experiments. Adipose tissue and vena cava were obtained and subjected to MSCs isolation and tissue decellularization, respectively. MSCs were subjected to differentiation using endothelial inductor growth factor (EIGF) obtained from human platelet lysates. Immunofluorescence, histological and immunohistochemical analyses were employed for the final characterization of the obtained blood vessel substitute. Results: The scaffolds were successfully decellularized with sodium dodecyl sulfate. MSCs actively adhered at the scaffolds, and through stimulation with EIGF were differentiated into functional endothelial cells, secreting significantly higher quantities of von Willebrand factor (0.85 μg/mL; P < .05) than cells cultivated under the same conditions, without EIGF (0.085 μg/mL). Cells with evident morphologic characteristics of endothelium were seen at the lumen of the scaffolds. These cells also stained positive for fascin protein, which is highly expressed by differentiated endothelial cells. Conclusions: Taken together, the use of decellularized bioscaffold and subcutaneous MSCs seems to be a potential approach to obtain bioengineered blood vessels, in the presence of EIGF supplementation. © 2013 Society for Vascular Surgery.

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Background: In the absence of autologous bone for harvesting, fresh-frozen bone allografts turned into an alternative for bone reconstruction procedures. Purpose: The purpose of this study was to make a histological analysis of fresh-frozen onlay bone allografts (ALs), compared with autografts, in patients who needed maxillary reconstruction prior to dental implants placement. Materials and Methods: Twelve patients with bone deficiencies (width inferior to 4mm) in the sites where the implants were planned were enrolled in the study. From these, six were elected to be treated with autogenous (AT) bone grafts and six with fresh-frozen bone AL. This last group included the patients who had absence of a convenient amount of bone in donor sites. Each patient received from one to six graft blocks, totalling to 12 ATs and 17 ALs. Seven months after grafting procedures, biopsies of the grafts were made using 2-mm internal diameter trephine burs, and processed for histological analysis. One biopsy was retrieved from each patient. Results: Clinically, all grafts were found to be firm in consistency and well-incorporated to the receptor bed. Histological analysis showed a large amount of necrotic bone surrounded by few spots of new-formed bone in the AL group, suggesting low rate of graft remodeling. In the AT group, an advanced stage of bone remodeling was seen. Conclusions: Human fresh-frozen bone block AL showed clinical compatibility for grafting procedures, although associated to slow remodeling process. Further studies are needed to define, at long term, the remodeling process chronology the clinical longitudinal results for fresh-frozen bone AL. Copyright © 2013 Wiley Periodicals, Inc.