Laser printing of silver-based micro-wires in ZrO2 substrate for smart implant applications

Smart implants are endowed with functions of sensing, actuating and control to solve problems that may arise during their use. The assembly of these functions along the implant surface is still a challenge. However, with the advent of 3D printing, it is possible to print on implants’ surface, communication channels or micro-antennas or even sensoric/actuating areas. Hence, a positive impact on the long-term performance of the implants (including hip, dental and knee) may be expected with the proposed approach. Despite titanium and Ti6Al4V titanium alloy are the standard choice for implants fabrication, 3Y-TZP (tetragonal 3% mol yttria-stabilized zirconia) has emerged as a ceramic material suitable to overcome titanium alloy problems, due to its numerous advantages. In this sense, this work is concerned with the ability of printing silver-based communication system in zirconia substrates by using laser technology. For this purpose, micro-cavities were created on ZrO2 substrate, where the silver powder was placed and sintered into them. Through the laser approach, silver-based wires with great quality and low resistivity values were achieved. The flexural strength results showed that the mechanical resistance of zirconia disks was affected by laser micro-wire printing, which decreased as the laser passage was performed. Based on the results, it is believed that the proposed approach seems to be effective for the manufacturing of implants with intrinsic capacities, useful for smart implant applications.This work has been supported by FCT (Fundação para a Ciência e Tecnologia - Portugal) in the scope of the projects UID/EEA/04436/ 2019 and NORTE-01-0145-FEDER-000018-HAMaBICo and Add.Additive_Manufacturing to Portuguese Industry_POCI-01-0247- FEDER-024533. Thank the CNPq (205791/2014-0) and CAPES for the financial support

Association between anaerobic components of the maximal accumulated oxygen deficit and 30-second Wingate test

The purpose of this study was to analyze the relationship between the anaerobic components of the maximal accumulated oxygen deficit (MAOD) and of the 30-second Wingate anaerobic test (30-WAnT). Nine male physical education students performed: a) a maximal incremental exercise test; b) a supramaximal constant workload test to determine the anaerobic components of the MAOD; and c) a 30-WAnT to measure the peak power (PP) and mean power (MP). The fast component of the excess post-exercise oxygen consumption and blood lactate accumulation were measured after the supramaximal constant workload test in order to determine the contributions made by alactic (ALMET) and lactic (LAMET) metabolism. Significant correlations were found between PP and ALMET (r=0.71; P=0.033) and between MP and LAMET (r=0.72; P=0.030). The study results suggested that the anaerobic components of the MAOD and of the 30-WAnT are similarly applicable in the assessment of ALMET and LAMET during high-intensity exercise

Influence of laser texturing on surface features, mechanical properties and low-temperature degradation behavior of 3Y-TZP

cited By 0This study aims to investigate the influence of different laser surface texturing parameters on Low-Temperature Degradation and mechanical properties of Yttria-tetragonal zirconia polycrystals (3Y-TZP), focused on biomedical applications. The roughness resulted from laser irradiation was characterized by Ra, Rt, Rsk and Rku parameters, as well by SEM analysis. Wettability tests were conducted as a guide to evaluate the ability of the textures to promote osseointegration. Eleven groups of samples were created, such as five according to the laser parameters used, three correspond to the thermal treatments performed and three as different standards. After laser irradiation, all 3Y-TZP samples became black having their whiteness recovered by thermal treatments, which was measured by color analysis. X-Ray photoelectron spectroscopy was used to evaluate chemical changes, presenting the formation of zirconium sub-oxides. These results were corroborated by wettability tests, which exhibited a decrease in surface energy after thermal treatments. Mechanical strength was evaluated by B3B tests, which reveals the potential of laser irradiation combined with thermal treatments for enhancing 3Y-TZP bending resistance and reliability. LTD was accessed by XRD and reveled laser irradiation as a promising approach able to improve the resistance of 3Y-TZP to this phenomenon. © 2019 Elsevier Ltd and Techna Group S.r.l

Toracoscopia aplicada à ressecção de fragmento pulmonar com o auxílio de sutura mecânica em eqüinos Thoracoscopy for resection of lung fragment in horses with the aid of mechanical suturing

Este trabalho visou à ressecção de fragmento dorsocaudal do lobo pulmonar caudal esquerdo com o auxílio de sutura mecânica por via toracoscópica. Foram utilizados 10 eqüinos clinicamente sadios, os quais foram sedados e mantidos em estação. O procedimento foi realizado no hemitórax esquerdo, por três acessos previamente programados: o primeiro acesso foi no 12º espaço intercostal (EIC), o segundo no 14º, 15º ou 16º EIC e o terceiro no 14º ou 15º EIC, conforme a necessidade de posicionamento dos instrumentos. Em todos os animais foi possível controlar o pneumotórax, sendo observada evolução clínica satisfatória durante o período pós-operatório, exceto em um animal. Os resultados obtidos indicam que, por meio da videotoracoscopia, pode-se realizar ressecção pulmonar parcial com uso de sutura mecânica em eqüinos e seu emprego na rotina hospitalar poderá contribuir para melhor compreensão e controle de enfermidades sediadas na cavidade torácica.<br>In this study, a dorsocaudal portion resection of the left caudal lung lobe was performed using an endoscopic stapler by thoracoscopic procedure. Ten healthy horses, eight males and two females were evaluated by clinical examination and submitted to the surgical procedure. The animals were sedated and maintained in standing position. The procedure was done in the left hemitorax using three access previously studied: the first portal was done at the 12th intercostal space (IS); the second one at the 14th, 15th, or 16th IS; and the third one at the 14th or 15th IS, in accordance with the necessity of positioning the instruments. The employed surgical technique seemed to be adequate in all animals, since it helped controlling the existing pneumothorax; furthermore, clinical recovery during the postoperative period was satisfactory, except for one animal. These results suggest that thoracoscopic may successfully be employed for partial lung resection in horses, using endoscopic staplers, and its practical use may contribute to the knowledge and resolution of thoracic diseases