Impact of the Curing Temperature on the Manufacturing Process of Multi-Nanoparticle-Reinforced Epoxy Matrix Composites.

This study aims to analyze the effect of the curing temperature of nano-reinforcements during the manufacturing process on the mechanical properties of composites involving graphene (GNP), carbon nanofibers (CNFs), and a hybrid mixture of these two nanoparticles. In this context, the type of nanoparticles, their content, their type of resin, and their hybridization were considered. The results showed that both nanoparticles increased the viscosity of the resin suspension, with an increase of between 16.3% and 38.2% for GNP nanoparticles and 45.4% and 74% for CNFs depending on the type of resin. Shrinkage was also affected by the addition of nanoparticles, as the highest results were obtained with GNP nanoparticles, with a 91% increase compared with the neat resin, and the lowest results were obtained with CNFs, with a decrease of 77% compared with the neat resin. A curing temperature of 5 °C promoted the best bending and hardness performance for all composites regardless of the type of resin and reinforcement used, with improvements of up to 24.8% for GNP nanoparticles and 13.52% for CNFs compared with the neat resin at 20 °C. Hybridization led to further improvements in bending properties and hardness compared with single-reinforcement composites due to a synergistic effect. However, the effectiveness of hybridization depends on the type of resin.

Secure Aggregation Protocol Based on DC-Nets and Secret Sharing for Decentralized Federated Learning.

In the era of big data, millions and millions of data are generated every second by different types of devices. Training machine-learning models with these data has become increasingly common. However, the data used for training are often sensitive and may contain information such as medical, banking, or consumer records, for example. These data can cause problems in people's lives if they are leaked and also incur sanctions for companies that leak personal information for any reason. In this context, Federated Learning emerges as a solution to the privacy of personal data. However, even when only the gradients of the local models are shared with the central server, some attacks can reconstruct user data, allowing a malicious server to violate the FL principle, which is to ensure the privacy of local data. We propose a secure aggregation protocol for Decentralized Federated Learning, which does not require a central server to orchestrate the aggregation process. To achieve this, we combined a Multi-Secret-Sharing scheme with a Dining Cryptographers Network. We validate the proposed protocol in simulations using the MNIST handwritten digits dataset. This protocol achieves results comparable to Federated Learning with the FedAvg protocol while adding a layer of privacy to the models. Furthermore, it obtains a timing performance that does not significantly affect the total training time, unlike protocols that use Homomorphic Encryption.

Evaluating the efficacy of biologics with and without methotrexate in the treatment of psoriatic arthritis: a network meta-analysis.

INTRODUCTION: An important consideration in the treatment of patients with psoriatic arthritis (PsA) is whether the addition of methotrexate (MTX) to biologics has greater efficacy than biologic monotherapy with respect to efficacy outcomes in these patients. OBJECTIVES: To conduct a network meta-analysis (NMA) comparing biologics by treatment class with and without MTX for treatment of adults with active PsA. METHODS: A systematic literature review (SLR) identified randomised, double-blinded, controlled trials, and a Bayesian NMA compared biologics with and without MTX by treatment class (tumour necrosis factor inhibitors (TNFi), interleukin-23 inhibitors (IL-23i) and IL-17i). Efficacy outcomes included American College of Rheumatology 20%, 50% and 70% (ACR20, ACR50 and ACR70) improvement response. RESULTS: The SLR initially identified 31 studies, of which 17 met feasibility criteria for the NMA by containing the 'without MTX' subgroup. For ACR20 efficacy (the most robust assessment examined), all active treatments were significantly better than placebo. No statistically significant differences were demonstrated between biologic monotherapy (for all classes examined) and biologics in combination with MTX for ACR20/50. IL-17i were comparable to IL-23i, and IL-17i were significantly better than TNFi for ACR20. Although limited by fewer trials, TNFi, IL-23i and IL-17i were not statistically different for ACR50/70. CONCLUSIONS: Concomitant use of MTX and biologics did not improve ACR efficacy outcomes versus biologic monotherapy. MTX does not appear to be necessary as a background therapy when biologics are used for the achievement of ACR20/50 responses in patients with PsA.

Thermal Study of Carbon-Fiber-Reinforced Polymer Composites Using Multiscale Modeling.

The layered fibers of carbon-fiber-reinforced polymer (CFRP) composites exhibit low thermal conductivity (TC) throughout their thickness due to the poor TC of the polymeric resin. Improved heat transmission inside the hydrogen storage tank during the filling process can reduce further compression work, and improved heat insulation can minimize energy loss. Therefore, it is crucial to understand the thermal properties of composites. This paper reports the thermal behavior of plain-woven CFRP composite using simulation at the micro-, meso-, and macro-scales. The TC was predicted numerically and compared to experimental findings and analytical models. Good results were found. Using the approach of multi-scale modeling, a parametric study was carried out to analyze in depth the influence of certain variables on thermal properties. The study revealed that both fiber volume fraction and temperature significantly influenced the TC of the composite, with the interphase fiber/matrix thickness following closely in terms of impact. The matrix porosity was found to have a relatively slighter impact, particularly within the porosity range of 5 to 15%.

WEDGE FRAGMENT VARIATIONS OF TIBIAL SHAFT FRACTURES WITH INTRAMEDULLARY NAILING.

Introduction: Tibial shaft fracture is the most common long-bone fracture, and the standard treatment is intramedullary (IM) nail fixation. Regardless of the development of this technique pseudoarthrosis remains prevalent. Objectives: Evaluate the correlation between wedge fragment size and displacement, displacement of the main fragments of the 42B2 type, and pseudoarthrosis incidence. Methods: We retrospectively assessed all patients with 42B2 type fracture treated with IM nailing between January, 2015 and December, 2019. Six radiographic parameters were defined for preoperative radiographs in the anteroposterior (AP) and lateral views. Another six parameters were defined for postoperative radiographs at three, six, and 12 months. The Radiographic Union Score for Tibial Fractures score was used to assess bone healing. Results: Of 355 patients with tibial shaft fractures, 51 were included in the study. There were 41 (82.0%) male patients, with a mean age of 36.7 years, 37 (72.5%) had open fractures, and 28 (54.9%) had associated injuries. After statistical analysis, the factors that correlated significantly with nonunion were wedge height > 18 mm, preoperative translational displacement of the fracture in the AP view > 18 mm, and final distance of the wedge in relation to its original anatomical position after IM nailing > 5 mm. Conclusion: Risk factors for nonunion related to the wedge and42B2 fracture are wedge height > 18 mm, initial translation in the AP view of the fracture > 18 mm, and distance > 5 mm of the wedge from its anatomical position after IM nailing. Evidence level III; Retrospective comparative study .

Introdução: A fratura da diáfise da tíbia é a fratura mais comum dentre os ossos longos, sendo o tratamento padrão a fixação com haste intramedular (HIM). Independentemente do desenvolvimento da técnica cirúrgica, a pseudoartrose continua prevalente. Objetivo: Avaliar a associação entre o tamanho e o desvio da cunha, os desvios dos fragmentos principais do tipo 42B2 e a incidência de pseudoartrose. Métodos: Avaliamos, retrospectivamente, todos os pacientes com fraturas tipo 42B2 tratados com hastes intramedulares entre janeiro de 2015 e dezembro de 2019. Seis parâmetros radiográficos foram definidos para as radiografias pré-operatórias nas incidências anteroposterior (AP) e perfil. Outros seis parâmetros foram definidos para as radiografias pós-operatórias em 3, 6 e 12 meses de acompanhamento pós-operatório. O Escore Radiográfico de União para as Fraturas da Tíbia (RUST) foi o instrumento usado para avaliar a consolidação óssea. Resultados: Dos 355 pacientes com fraturas da diáfise da tíbia, 51 foram incluídos no estudo. Os pacientes incluídos foram 41 (82,0%) do sexo masculino, com idade média de 36,7 anos, 37 (72,5%) com fraturas expostas e 28 (54,9%) com lesões associadas. Após análise estatística, os fatores que se correlacionaram significativamente com a não consolidação foram a altura da cunha > 18 mm, o deslocamento translacional pré-operatório da fratura na incidência AP > 18 mm e a distância final da cunha em relação à sua posição anatômica original após a cravação do MI > 5 mm. Conclusão: Os fatores de risco para a pseudartrose relacionada com a fratura em cunha e42B2 são a altura da cunha > 18 mm, a translação inicial na vista AP da fratura > 18 mm e a distância > 5 mm da cunha em relação à sua posição anatómica após a fixação IM. Nível de evidência III; estudo comparativo retrospectivo. Nível de evidência III; Estudo retrospectivo comparativo .

A forensic evaluation method for DeepFake detection using DCNN-based facial similarity scores.

Detecting DeepFake videos has become a central task in modern multimedia forensics applications. This article presents a method to detect face swapped videos when the portrayed person in the video is known. We propose using a threshold classifier based on similarity scores obtained from a Deep Convolutional Neural Network (DCNN) trained for facial recognition. We compute a set of similarity scores between faces extracted from questioned videos and reference materials of the person depicted. We use the highest score to classify the questioned videos as authentic or fake, depending on the threshold chosen. We validate our method on the Celeb-DF (v2) dataset (Li et al., 2020) [13]. Using the training and testing splits specified on the dataset, we obtained an HTER of 0.020 and an AUC of 0.994, surpassing the most robust approaches against this dataset (Tran et al., 2021) [37]. Additionally, a logistic regression model was used to convert the highest score into a likelihood ratio for greater applicability in forensic analyses.

Effect of Carbon Nanofibers on the Strain Rate and Interlaminar Shear Strength of Carbon/Epoxy Composites.

The static bending properties, different strain rates and interlaminar shear strength (ILSS) of carbon-fiber-reinforced polymers (CFRP) with two epoxy resins nano-enhanced with carbon nanofibers (CNFs) are studied. The effect on ILSS behavior from aggressive environments, such as hydrochloric acid (HCl), sodium hydroxide (NaOH), water and temperature, are also analyzed. The laminates with Sicomin resin and 0.75 wt.% CNFs and with Ebalta resin with 0.5 wt.% CNFs show significant improvements in terms of bending stress and bending stiffness, up to 10%. The values of ILLS increase for higher values of strain rate, and in both resins, the nano-enhanced laminates with CNFs show better results to strain-rate sensitivity. A linear relationship between the logarithm of the strain rate was determined to predict the bending stress, bending stiffness, bending strain and ILSS for all laminates. The aggressive solutions significantly affect the ILSS, and their effects are strongly dependent on the concentration. Nevertheless, the alkaline solution promotes higher decreases in ILSS and the addition of CNFs is not beneficial. Regardless of the immersion in water or exposure to high temperatures a decrease in ILSS is observed, but, in this case, CNF content reduces the degradation of the laminates.

Numerical Simulations of the Low-Velocity Impact Response of Semicylindrical Woven Composite Shells.

This paper presents an efficient and reliable approach to study the low-velocity impact response of woven composite shells using 3D finite element models that account for the physical intralaminar and interlaminar progressive damage. The authors' previous work on the experimental assessment of the effect of thickness on the impact response of semicylindrical composite laminated shells served as the basis for this paper. Therefore, the finite element models were put to the test in comparison to the experimental findings. A good agreement was obtained between the numerical predictions and experimental data for the load and energy histories as well as for the maximum impact load, maximum displacement, and contact time. The use of the mass-scaling technique was successfully implemented, reducing considerably the computing cost of the solutions. The maximum load, maximum displacement, and contact time are negligibly affected by the choice of finite element mesh discretization. However, it has an impact on the initiation and progression of interlaminar damage. Therefore, to accurately compute delamination, its correct definition is of upmost importance. The validation of these finite element models opens the possibility for further numerical studies on of woven composite shells and enables shortening the time and expenses associated with the experimental testing.

Effect of Carbon Nanofibers on the Viscoelastic Response of Epoxy Resins.

Two epoxy resins with different viscosities were enhanced up to 1 wt.%, applying a simple method with carbon nanofibers (CNFs). These were characterized in terms of static bending stress, stress relaxation, and creep tests. In bending, the contents of 0.5 wt.% and 0.75 wt.% of CNFs on Ebalta and Sicomin epoxies, respectively, promote higher relative bending stress (above 11.5% for both) and elastic modulus (13.1% for Sicomin and 16.2% for Ebalta). This highest bending stress and modulus occurs for the lower viscosity resin (Ebalta) due to its interfacial strength and dispersibility of the fillers. Creep behaviour and stress relaxation for three stress levels (20, 50, and 80 MPa) show the benefits obtained with the addition of CNFs, which act as a network that contributes to the immobility of the polymer chains. A long-term experiment of up to 100 h was successfully applied to fit the Kohlrausch-Williams-Watts (KWW) and Findley models to stress relaxation and creep behaviour with very good accuracy.

Multi-scale approach to assess total porosity and pore size in four different kinds of carbonate rocks.

Petroleum is, at present, still the main energy source in the world. Most of it is stored in carbonate rock reservoirs with complex inner structures and pores ranging from nanometers to dozens of meters. Knowing the rock's entire pore network is indispensable to perform an effective petroleum extraction. X-ray microtomography, a technique that generates images from samples' inner structure and a powerful tool to evaluate the 3D pore network, was employed in this scientific research to scan four kinds of carbonate rocks (Dolomite, Desert Pink, Indiana, and Winterset) in five different pore scales (90 µm, 13 µm, 5.5 µm, 1.0 µm, and 65 nm). A multi-scale approach based on the number of pores was applied to integrate different pore scale data and assess the total porosity as well as each sample pore size distribution. The results were compared to classical Mercury Injection Capillary Pressure (MICP) results, demonstrating a fair agreement in total porosity in the two samples. Multi-scale porosity of the Dolomite sample was 17.7% against (18.9 ± 2.1)% of the MICP porosity. The Winterset sample had multi-scale porosity of 26.2%, while MICP porosity was (31.2 ± 0.6)%. Pore size distribution results were rather satisfactory, especially when overlapping regions in different scales were compared. In general, the multi-scale approach showed good potential. It still needs further evaluation to fine-tune some procedures and fluid flow simulation tests but might become a useful tool to study reservoir rocks with a wide range of pore sizes, such as carbonate rocks.

Re-entry catheters in subintimal lower limb recanalization: up to date.

In their daily practice, vascular specialists face the challenge of treating peripheral artery disease (PAD) of the lower limbs. During the last decade, there has been an increasing adoption of endovascular techniques worldwide and a simultaneous expansion of the endovascular instrument portfolio to improve technical results during PAD treatment. The proper use of dedicated endovascular devices is essential to achieve technical success. To know indication, mechanism of action, and possible complications of different devices is of paramount importance to achieve immediate procedural success in the shortest time possible and long-term patency of the treated vessels. All the re-entry catheters on the market are presented with their own unique characteristics. The pros and cons of the use of these devices is also discussed and compared to other possible recanalization strategies. The re-entry devices have been demonstrated to be effective in increasing the procedural success rate, in limiting the dissection of distal healthy vessel segments and shortening the procedural time. They should therefore be considered part of essential tools in the treatment of lower limb chronic total occlusions especially for clinicians who do not feel comfortable in performing retrograde access.

Wedge fragment variations of tibial shaft fractures with intramedullary nailing / Fragmento em cunha das fraturas da diáfise da tíbia com haste intramedular

ABSTRACT Introduction: Tibial shaft fracture is the most common long-bone fracture, and the standard treatment is intramedullary (IM) nail fixation. Regardless of the development of this technique pseudoarthrosis remains prevalent. Objectives: Evaluate the correlation between wedge fragment size and displacement, displacement of the main fragments of the 42B2 type, and pseudoarthrosis incidence. Methods: We retrospectively assessed all patients with 42B2 type fracture treated with IM nailing between January, 2015 and December, 2019. Six radiographic parameters were defined for preoperative radiographs in the anteroposterior (AP) and lateral views. Another six parameters were defined for postoperative radiographs at three, six, and 12 months. The Radiographic Union Score for Tibial Fractures score was used to assess bone healing. Results: Of 355 patients with tibial shaft fractures, 51 were included in the study. There were 41 (82.0%) male patients, with a mean age of 36.7 years, 37 (72.5%) had open fractures, and 28 (54.9%) had associated injuries. After statistical analysis, the factors that correlated significantly with nonunion were wedge height > 18 mm, preoperative translational displacement of the fracture in the AP view > 18 mm, and final distance of the wedge in relation to its original anatomical position after IM nailing > 5 mm. Conclusion: Risk factors for nonunion related to the wedge and42B2 fracture are wedge height > 18 mm, initial translation in the AP view of the fracture > 18 mm, and distance > 5 mm of the wedge from its anatomical position after IM nailing. Evidence level III; Retrospective comparative study .

RESUMO Introdução: A fratura da diáfise da tíbia é a fratura mais comum dentre os ossos longos, sendo o tratamento padrão a fixação com haste intramedular (HIM). Independentemente do desenvolvimento da técnica cirúrgica, a pseudoartrose continua prevalente. Objetivo: Avaliar a associação entre o tamanho e o desvio da cunha, os desvios dos fragmentos principais do tipo 42B2 e a incidência de pseudoartrose. Métodos: Avaliamos, retrospectivamente, todos os pacientes com fraturas tipo 42B2 tratados com hastes intramedulares entre janeiro de 2015 e dezembro de 2019. Seis parâmetros radiográficos foram definidos para as radiografias pré-operatórias nas incidências anteroposterior (AP) e perfil. Outros seis parâmetros foram definidos para as radiografias pós-operatórias em 3, 6 e 12 meses de acompanhamento pós-operatório. O Escore Radiográfico de União para as Fraturas da Tíbia (RUST) foi o instrumento usado para avaliar a consolidação óssea. Resultados: Dos 355 pacientes com fraturas da diáfise da tíbia, 51 foram incluídos no estudo. Os pacientes incluídos foram 41 (82,0%) do sexo masculino, com idade média de 36,7 anos, 37 (72,5%) com fraturas expostas e 28 (54,9%) com lesões associadas. Após análise estatística, os fatores que se correlacionaram significativamente com a não consolidação foram a altura da cunha > 18 mm, o deslocamento translacional pré-operatório da fratura na incidência AP > 18 mm e a distância final da cunha em relação à sua posição anatômica original após a cravação do MI > 5 mm. Conclusão: Os fatores de risco para a pseudartrose relacionada com a fratura em cunha e42B2 são a altura da cunha > 18 mm, a translação inicial na vista AP da fratura > 18 mm e a distância > 5 mm da cunha em relação à sua posição anatómica após a fixação IM. Nível de evidência III; estudo comparativo retrospectivo. Nível de evidência III; Estudo retrospectivo comparativo .

Tissue healing changes on wounds in rats after treatment with Hancornia speciosa latex in cream-gel formulation.

PURPOSE: Hancornia speciosa latex has shown pharmacological potential in wound healing processes due to its angiogenic, osteogenic, and anti-inflammatory activities. The aims of this study were to carry out a cream-gel formulation with 5, 10 and 25% of H. speciosa serum latex and to evaluate its potential to stimulate the skin regeneration in rats' wounds. METHODS: One hundred and twenty rats were divided into five groups: neutral control with saline (G1), cream-gel based on H. speciosa latex serum at 5% m/v (G2), cream-gel at 15% m/v (G3), cream-gel at 25% m/v (G4), and cream-gel (G5). The animals were euthanized at three, seven, 14 and 21 days after the injury induction, and some parameters were analyzed: wound contraction, necrosis, fibrin, polymorphonuclear and mononuclear infiltrates, fibroblast, angiogenesis, hemorrhage, and collagen. RESULTS: The therapeutic treatment with cream-gel at 15 and 25% is beneficial in the inflammatory phase of healing processes since it increased the angiogenesis and proliferation of mononuclear infiltrations in wounds. Regarding wound contraction, the treatment with cream-gel (5 and 15%) induced a higher rate of contraction in the proliferative phase. The 15% cream-gel formulation stimulated a greater production of collagen in the injured tissues. CONCLUSIONS: H. speciosa cream-gel is a low-cost herbal medicine which can aid in tissue repair.

Effect of Impact Position on Repaired Composite Laminates Subjected to Multi-Impacts.

Because the certification of aircraft structures requires significant costs and time-consuming experimental tests, all the studies carried out are strong contributions to the applicability of repairs based on adhesively bonded fibre composite patches. In this context, the main goal of this study aims to analyse the effect of the impact position on the multi-impact response of repaired composites. The results will be compared with those obtained in composites containing holes. Therefore, experimental tests will be carried out using an energy of 8 J and centrally supported samples. It was noted that the patch region proved to be very sensitive to impact due to its thickness. Full perforation occurred after two to three impacts, and to obtain higher strength it would be necessary to increase the thickness of the patch. However, depending on the location of the repair, this could bring aerodynamic problems. For the distance of 15 mm from the centre, an overlap region, the repaired laminate shows 494.7% higher impact strength than a laminate with a hole. In this case, the effect of the stress concentration is determinant in the impact fatigue life. Finally, for the 35 mm distances that are close to the border, no significant changes in impact fatigue life were observed for both the repaired laminates and those containing the hole. This leads to the conclusion that the border effect is much more significant than the presence of the hole for this distance.

Numerical Modeling of Damage Caused by Seawater Exposure on Mechanical Strength in Fiber-Reinforced Polymer Composites.

Fiber-reinforced polymer composites are frequently used in marine environments which may limit their durability. The development of accurate engineering tools capable of simulating the effect of seawater on material strength can improve design and reduce structural costs. This paper presents a numerical-based approach to predict the stress-strain response of fiber-reinforced polymer composites exposed to different seawater immersion times, ranging from 0 to 900 days. A three-dimensional numerical model has been implemented using a static implicit finite element analysis along with a user-defined material (UMAT) subroutine. Puck's failure criterion was used for ultimate failure analysis of the laminates, while Fick's first diffusion law was used to predict the seawater absorption rate. Overall, the simulated stress-strain curves were close to those obtained experimentally. Moreover, the model agreed well with the experimental data regarding the maximum stress and the strain at failure leading to maximum errors lower than 9% and 11%, respectively. Additionally, the simulated strain fields agreed well with the experimental results measured by digital image correlation. Finally, the proposed procedure was also used to identify the most critical surfaces to protect the mechanical components from marine environments.

Optimization of Printing Parameters to Maximize the Mechanical Properties of 3D-Printed PETG-Based Parts.

Fused filament fabrication (FFF) is the most popular additive manufacturing method, which allows the production of highly complex three-dimensional parts with minimal material waste. On the other hand, polyethylene terephthalate glycol (PETG) has been used to replace traditional polymers for 3D printing due to its chemical resistance and mechanical performance, among other benefits. However, when fibres are added, these PETG-based composites can be suitable for many different applications. Nevertheless, to guarantee their good performance in-service in these applications, and even extend to new ones, it is necessary for their mechanical properties to be maximized. Therefore, this study intends to optimize the printing parameters (nozzle temperature, printing speed, layer height and filling) in order to maximize the mechanical properties of printed PETG, PETG+CF (carbon fibre-reinforced PETG composites) and PETG+KF (aramid fibre-reinforced PETG composites). The Taguchi method was used for the experimental procedure design, and the specimens were produced according to the L16 orthogonal array. Finally, an analysis of variance (ANOVA) was performed, with a 95% confidence interval, to analyse the effect of the printing parameters on the bending properties. It was possible to conclude that the best bending properties for PETG, PETG+CF and PETG+KF were obtained for extrusion temperatures of 265 °C, 195 °C and 265 °C, printing speeds of 20, 60 and 20 mm/s, layer heights of 0.4, 0.53 and 0.35 mm and an infill density of 100% for the three materials, respectively.

RADIOLOGICAL RESULTS OF SEVERE SCFE TREATMENT AT IOT-FMUSP FROM 2012 TO 2018.

Objective: To assess the complications in patients with severe slipped capital femoral epiphysis treated with the Dunn or modified Dunn procedure from 2012 to 2018 at the Institute of Orthopedics and Traumatology, Medical School, Universidade de São Paulo. Methods: Analysis of medical records, preoperative and postoperative radiographs with at least one year of radiographic follow-up of patients with severe slipped capital femoral epiphysis. Results: We reviewed the complications in 19 operated cases from 2012 to 2018, out of which 36.8% had osteonecrosis of the femoral head, one patient had chondrolysis, and another had postoperative infection. Conclusion: The osteonecrosis rate observed in this series of cases is similar to that described in other orthopedic facilities. We assessed factors that could potentially influence this outcome, including other characteristics of the patient (obesity, endocrine diseases, and history of sports activities) and of the health system. Level of Evidence III, Restropective Case Series.

Objetivo: Avaliar as complicações apresentadas nos pacientes com epifisiolistese grave tratados por meio do procedimento de Dunn ou Dunn Modificado entre 2012 e 2018 no IOT-FMUSP. Métodos: Análise de prontuários, radiografias pré-operatórias e radiografias pós-operatórias com pelo menos 1 ano de seguimento radiográfico dos pacientes com epifisiolistese grave. Resultados: Analisou-se a presença de complicações em 19 casos operados de 2012 a 2018. Desses pacientes, 36,8% apresentaram osteonecrose da cabeça femoral, oi observada condrólise em 1 paciente e infecção pós-operatória em 1 paciente. Conclusão: A taxa de osteonecrose observada nesta série de casos está próxima à descrita em outros serviços. Alguns fatores que potencialmente influenciariam neste desfecho poderiam ter sido avaliados, como outras características do paciente (obesidade, doenças endócrinas e atividade esportiva) e do sistema de saúde. Nível de Evidência III, Série Retrospectiva de Casos .

Hybridization Effects on Bending and Interlaminar Shear Strength of Composite Laminates.

Fiber-reinforced composites are gradually replacing the traditional materials in many engineering applications. However, for many applications these materials are still unsuitable, due to their lack of toughness. In this context, hybridization is a promising strategy in which two or more types of fiber are combined to obtain a better balance of mechanical properties compared to non-hybrid composites. Therefore, the main goal of this work is to study the hybridization effect on the static performance and interlaminar shear strength. For this purpose, carbon, glass, and Kevlar fibers were used and combined in different proportions. It was possible to conclude that there is an ideal value of fiber content to maximize both properties and, depending on the type of fiber, they should be placed specifically on the compression or tensile side. For example, for composites involving carbon and glass fibers the latter must be placed on the compression side, and for a value of 17% by weight the flexural strength decreases by only 2.8% and the bending modulus by around 19.8%. On the other hand, when Kevlar fibers are combined with glass or carbon fibers, the Kevlar ones must always be placed on the tensile side and with an ideal value of 13% by weight.