6 resultados para fracture repair
em Universidade do Minho
Resumo:
Imaging techniques are the standard method for assessment of fracture healing processes. However, these methods are perhaps not entirely reliable for early detection of complications, the most frequent of these being delayed union and non-union. A prompt diagnosis of such disorders could prevent prolonged patient distress and disability. Efforts should be directed towards the development of new technologies for improving accuracy in diagnosing complications following bone fractures. The variation in the levels of bone turnover markers (BTMs) have been assessed with regard to there ability to predict impaired fracture healing at an early stage, nevertheless the conclusions of some studies are not consensual. In this article the authors have revised the potential of BTMs as early predictors of prognosis in adult patients presenting traumatic bone fractures but who did not suffer from osteopenia or postmenopausal osteoporosis. The available information from the different studies performed in this field was systematized in order to highlight the most promising BTMs for the assessment of fracture healing outcome.
Resumo:
In this research, five types of polymer repair materials were selected for investigation of the influence of sample shape, deformation rate and test temperature on the mechanical properties determined with an uniaxial tensile test. The results showed the clear effect of measurement conditions on tensile strength, elongation and modulus of elasticity. The highest tensile strength and modulus of elasticity were exhibited by epoxy resin for the filling of concrete cracks, which achieved 1% elongation. The lowest coefficient of dispersion characterized the results of tensile test carried out using dumbbell samples at a deformation rate of 50 mm/min. The effect of temperature varied with the material type.
Resumo:
Identification of the tensile constitutive behaviour of Fibre Reinforced Concrete (FRC) represents an important aspect of the design of structural elements using this material. Although an important step has been made with the introduction of guidance for the design with regular FRC in the recently published fib Model Code 2010, a better understanding of the behaviour of this material is still necessary, mainly for that with self-compacting properties. This work presents an experimental investigation employing Steel Fibre Self-Compacting Concrete (SFRSCC) to cast thin structural elements. A new test method is proposed for assessing the post-cracking behaviour and the results obtained with the proposed test method are compared with the ones resulted from the standard three-point bending tests (3PBT). Specimens extracted from a sandwich panel consisting of SFRSCC layers are also tested. The mechanical properties of SFRSCC are correlated to the fibre distribution by analysing the results obtained with the different tests. Finally, the stress-crack width constitutive law proposed by the fib Model Code 2010 is analysed in light of the experimental results.
Resumo:
Background Despite the small size of the incision, the scar left by open repair of epigastric hernia in children is unaesthetic. Few laparoscopic approaches to epigastric hernia repair have been previously proposed, but none has gain wide acceptance from pediatric surgeons. In this study, we present our experience with a scarless laparo- scopic approach using a percutaneous suturing technique for epigastric hernia repair in children. Methods Ten consecutive patients presenting with epi- gastric hernia 15 mm or further from the umbilicus were submitted to laparoscopic hernia repair. A 5-mm 308-angle laparoscope is introduced through a umbilical trocar and a 3-mm laparoscopic dissector is introduced through a stab incision in the right flank. After opening and dissecting the parietal peritoneum, the fascial defect is identified and closed using 2–0 polyglactin thread through a percutaneous suturing technique. Intraoperative and postoperative clinical data were collected. Results All patients were successfully submitted to la- paroscopic epigastric hernia repair. Median age at surgery was 79 months old and the median distance from the um- bilicus to the epigastric defect was 4 cm. Operative time ranged from 35 to 75 min. Every hernia was successfully closed without any incidents. Follow-up period ranges from 2 to 12 months. No postoperative complications or recurrence was registered. No scar was visible in these patients. Conclusion This scarless laparoscopic technique for epi- gastric hernia repair is safe and reliable. We believe this technique might become gold standard of care in the near future.
Resumo:
Tese de Doutoramento em Engenharia Civil
Resumo:
Ideal candidates for the repair of robust biological tissues should exhibit diverse features such as biocompatibility, strength, toughness, self-healing ability and a well-defined structure. Among the available biomaterials, hydrogels, as highly hydrated 3D-crosslinked polymeric networks, are promising for Tissue Engineering purposes as result of their high resemblance with native extracellular matrix. However, these polymeric structures often exhibit a poor mechanical behavior, hampering their use in load-bearing applications. During the last years, several efforts have been made to create new strategies and concepts to fabricate strong and tough hydrogels. Although it is already possible to shape the mechanical properties of artificial hydrogels to mimic biotissues, critical issues regarding, for instance, their biocompatibility and hierarchical structure are often neglected. Therefore, this review covers the structural and mechanical characteristics of the developed methodologies to toughen hydrogels, highlighting some pioneering efforts employed to combine the aforementioned properties in natural-based hydrogels.