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Orthopedic plates are currently used in bone healing process. However they cause density loss because of the change in natural stress patterns.The aim of this study was to evaluate a newly developed bone plate using functional graded material in term of stress pattern. In the present study, 3D finite element models of tibial bone plate with variable stiffness of a graded material and traditional bone plates made of stainless steel and Ti alloy have been developed by using the ABAQUS software. Effects on the predicted stresses at the fracture site in the presence of a distance between the plate and fractured bone were also studied. For this purpose, a 3D model of tibia was created with the exact geometry of the real bone geometry by using CT scan images of a human left leg. Results showed that the bone plate with graded material offers less stress-shielding to the bone, providing a higher compressive stress at bone to induce accelerated healing in comparison with Ti alloy and stainless-steel bone plate. Results also showed that the use of non-contact plates provide a favorable mechanical environment for the following fracture healing.

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Researchers are currently directing their efforts toward developing new enzyme stabilization and enhancement strategies to broaden their application in various industries. This study utilized a unified platform to stabilize and safeguard proteins in industrial settings. Despite the wide-ranging industrial applications of lipases, their utility in industrial processes is limited by their susceptibility to degradation under harsh environmental conditions. In our study, we used a dual-purpose strategy that involved both enzyme stabilization and the shielding of an organosilica protective layer. After expressing and purifying the recombinant lipase enzyme, we immobilized it onto silica nanoparticles and shielded it with an organosilica nanolayer to protect the enzyme. We meticulously examined the optimal thickness of the protective layer and its influence on enzyme stabilization against environmental stressors. Our research findings demonstrate that the immobilized enzyme exhibited a remarkable level of stability compared to its free enzyme when subjected to various factors, such as fluctuations in temperature and exposure to chemical agents. Furthermore, the immobilized samples displayed optimal activity across a broad range of temperatures, highlighting this approach's adaptability and efficacy. Notably, the organosilica layer significantly bolstered the reactivity recovery of denatured proteins with SDS and urea, highlighting the versatile applications of this method. These findings indicated that our present platform has great potential to improve the efficiency and stability of industrial enzymes against various environmental challenges.
 

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Today in the world, including in our country, the use of nuclear technology in various fields of power plants, industry, agriculture and medicine is expanding. One of the most important issues in nuclear technology is nuclear radiation protection to prevent harmful environmental, pathogenic and harmful effects on some of the precision measuring instruments. From the perspective of preservation, all the radiation and particles are not of the same importance, because their penetration and impact on different materials, such as living tissue, are not equal. In the discussion of conservation, neutron and gamma radiation is of particular importance because, due to its unloaded nature, they can pass relatively large thicknesses of the shield and contribute to raising the dose rate outside the shield. In addition to the many uses of radioactive waste, it should be noted that this radiation damages cells and living tissues and protection against it is essential and inevitable. In order to protect against radiation, absorbent materials should have a high density, high attenuation coefficient, and structural properties with high strength, easy to provide and cheap production. According to the above, the use of concrete is a suitable alternative for radiation protection. Due to its high specificity and low cost, barite is widely used in the oil and gas drilling industry, coloring industry, pharmaceutical plastics (due to the absorption of radioactive wastes), chemicals and so on. So it can be a good option for gamma radiation protection. In this research gamma-ray linear attenuation coefficient and neutron beam dispersion cross-section of two series of concrete samples containing barite powder as a substitute of sand with and without graphite powder under gamma rays with Cs-137 fountain and NaI (Tl) detector under neutron beam With the Am-Be 241 fountain and the BF₃ detector. The compressive strength, tensile strength and ultrasonic pulse velocity were also determined. All concrete samples, with the exception of control samples, have been made with 400 kg / m³ cement and 0.4 water/cement ratio with 10% microsilicon replacement in two series. In the first series, barite powder was replaced with 10, 25, 50, 75 and 100% replacement of sand, and in the second, 10% of the graphite powder was added to samples containing various powdered barite powder. The result of this study showed that a sample containing 10% barite powder plus 10% graphite powder could be an optimal amount for a concrete protected against gamma and neutron rays.