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Metallic materials have received special attention in the aerospace and defense areas. A few decades ago, Brazil was faced with technological challenges concerning the production and processing of ultra-high strength steels, such as AISI 4340 and SAE 300 M steels. The AISI 4130 steel had been also considered, since it is applied in landing gears, small aircrafts engine cradles, and besides general industries. In this work, as a comparative welding process, Laser Beam Welding (LBW) was used as an alternative to the traditional TIG (Tungsten Inert Gas) welding. For the mechanical characterization of laser and TIG welds, tensile and hardness tests were performed. Microstructural characterization through optical microscopy was realized as well, in the fusion zone (FZ) and heat-affected zone (HAZ). Martensite was found in the fusion zone for both processes. However the average grain sizes were different due to different heating and cooling rates. In the present study, the weld was autogenous and a post weld heat treatment was conducted to evaluate its influence on mechanical properties. This treatment proved to improve the ductility of the steel and reducing the embrittlement in the welded region. It was observed that the thicknesses of the FZ and HAZ in the TIG welds were ten times larger than in the laser. The hardness values observed in FZ and HAZ were similar in both cases. Tensile strength after heat treatment remained at levels similar to the base material. After the heat treatment, there was a recover in the material ductility, particularly after the laser welding, demonstrating the usefulness of the process. [ABSTRACT FROM AUTHOR]

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Prediction of wave forces on caisson-type breakwaters is challenging, especially in the case of impact loads that strongly depend on wave reflection, and wave breaking which affects the wave characteristics near the structure. In recent years, numerical models have been further developed and their use is becoming increasingly attractive, such as the Smoothed Particle Hydrodynamics (SPH) numerical models which enable the simulation of complex free surface flows. The SPH numerical model developed at the National Laboratory for Civil Engineering (LNEC) is validated by comparing the numerical results of the wave interaction with a vertical wall using data obtained from physical modeling tests carried out in one of the LNEC׳s flumes. The numerical results presented a good agreement with the physical model tests. The free surface level was well estimated, with a concordance index between numerical results and experimental data of about 90.5-99.1%, presenting an average value of 95.5%. Pressure at the vertical wall shows high intensity and short duration impact loads, and presented a concordance index between numerical results and experimental data about 68.8-94.4%, with an average value about 86.2%. Considering the complex phenomena involved, which is highly difficult to be accurately modeled, numerically and experimentally, a good agreement between physical tests and numerical results was accomplished. [ABSTRACT FROM AUTHOR]

Knowledge of the anatomy of the hepatic artery and its variations is important to hepatobiliary and liver transplant surgeons and interventional radiologists. We report a rare anatomic variation of liver hepatic arterial supply: a right accessory hepatic artery arising directly from the celiac trunk and observed at the time of multiorgan procurement. The anatomic variation described in this case occurs in up to 2% of cases and their knowledge is essential to avoid injuries during multiorgan procurement that could require multiple anastomoses or lead to inadvertent vessel injury. This variation is very rarely reported in the medical literature. We document successful deceased-donor liver transplantation with a graft that had an accessory right accessory hepatic artery from the celiac trunk. [ABSTRACT FROM AUTHOR]

Aims Pro-inflammatory mediators, glucocorticoids and transforming growth factor (TGF)-β are implicated in the pathogenesis of non-alcoholic steatohepatitis (NASH)-related insulin resistance. As physical activity is beneficial against NASH, we analyzed the voluntary physical activity (VPA) and endurance training (ET) (preventive and therapeutic strategies) effects on hepatic insulin, pro-inflammatory and glucocorticoid signaling regulators/mediators in high-fat (Lieber-DeCarli) diet (HFD)-induced NASH. Main methods Adult male Sprague–Dawley rats were divided in standard diet (SD) or HFD, with sedentary, VPA and ET animals in both diet regimens. Plasma glucose and insulin concentrations were analyzed; plasma insulin sensitivity index (ISI) was calculated. Hepatic insulin, pro-inflammatory and glucocorticoid signaling regulators/mediators were evaluated by Western blot or reverse transcriptase-PCR. Key findings ET improved ISI in both diet regimens. HFD-feeding increased interleukin-1β and induced a similar pattern on interleukin-6 and TGF-β, which were globally reduced by physical exercise. ET decreased HFD leukemia inhibitory factor level, SD + VPA animals presenting higher values than HFD + VPA animals. HFD increased the ratio of IRS-1 Ser307 /total IRS-1, which was completely mitigated by physical exercise. Physical exercise reduced total ERK and JNK (total and activated) expression in HFD. In SD vs . HFD, VPA presented higher activated JNK and ET presented higher total JNK. Generally, in HFD, the ratio (activated/total) of AKT, and each separately, decreased with exercise and also for activated AKT in SD. Overall, in both diets, exercise reduced 11β-hydroxysteroid dehydrogenase type 1. ET increased glucocorticoid receptor and reduced PTP1B in HFD. Significance Physical exercise mitigates the expression of pro-inflammatory mediators and positively modulates insulin and glucocorticoid signaling in NASH. [ABSTRACT FROM AUTHOR]

This work provides an estimation of the exposure of the Portuguese population to ionizing radiation due to radiodiagnostic (x-ray and nuclear medicine (NM)) procedures, between 2013 and 2017, using the methodology proposed by the European Commission. Obtained results show that the estimated annual mean effective dose to the Portuguese population due to x-ray procedures increased by about 16%, from 0.75 ± 0.48 mSv per caput in 2013 to 0.89 ± 0.56 mSv per caput in 2017. The x-ray exam type that contributes the most to the collective dose in Portugal is Computed Tomography (CT). In the case of nuclear medicine, an increase in the annual effective dose from 0.088 ± 0.001 mSv per caput in 2013 to 0.090 ± 0.002 mSv per caput in 2017 was observed, with the procedures that contribute the most to the collective dose being bone imaging and cardiac procedures. This study intends to raise awareness to the need of optimization of radiation dose in medical procedures. • Evaluates collective dose in Portuguese population due to radiodiagnostic exams. • Studies trends for the past 8 years. • Compares data with other European countries. [ABSTRACT FROM AUTHOR]