Bone Scaffold

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1 - Micro-Finite Element Model to Investigate the Mechanical Stimuli in Scaffolds Fabricated via Space Holder Technique for Cancellous Bone
Sayed Alireza Hashemi Saeid Esmaeili Mazyar Ghadirinejad Saeed Saber-Samandari Erfan Sheikhbahaei Alireza Kordjamshidi Amirsalar Khandan

In Osteoporosis, bone mechanical strength decreases and as a result, the risk of bone fracture increases. Osteoporosis is also referred as a "silent illness" since it usually develops asymptomatic until it breaks a long bone, like the femur. In recent years, porous scaf چکیده کامل

In Osteoporosis, bone mechanical strength decreases and as a result, the risk of bone fracture increases. Osteoporosis is also referred as a "silent illness" since it usually develops asymptomatic until it breaks a long bone, like the femur. In recent years, porous scaffolds have been utilized to repair damaged bone tissue. For bone tissue engineering, synthetic scaffolds should have acceptable mechanical properties, in addition to the required biological properties. In this regard, the finite element simulation is used to predict the mechanical properties of porous bone scaffolds as one of the most common methods for reducing the experimental tests, because the acquisition of mechanical properties of such scaffolds is very time-consuming and expensive. Due to the widespread use of hydroxyapatite (HA) in the manufacture of bone scaffold composites, the mechanical properties of HA-wollastonite scaffold composites are obtained by laboratory tests and finite element methods. Comparison of the simulation of finite element analysis (FEA) and the experimental results indicate the success of the FEA simulation. In conclusion, new finding satisfied expectations as being suitable for mechanical and biomaterial aspect of a porous scaffold which is proven by laboratory tests and FEA simulations. Due to that fact, the result of this study can be employed to obtain scaffolds well-suited for bone implementations. پرونده مقاله

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2 - Fabrication of polycaprolactone and polylactic acid shapeless scaffolds via fused deposition modelling technology
Amirsalar Khandan Saeid Esmaeili

The porous scaffold provides a temporary environment for bone growth and facilitates cell adhesion, cell growth and differentiation. In the present study, polymeric scaffolds were designed and fabricated via fused deposition modelling (FDM) method for orthopedic defect چکیده کامل

The porous scaffold provides a temporary environment for bone growth and facilitates cell adhesion, cell growth and differentiation. In the present study, polymeric scaffolds were designed and fabricated via fused deposition modelling (FDM) method for orthopedic defect approaches using polycaprolactone (PCL) and polylactic acid (PLA) polymer. The prepared scaffold was coated with Chitosan-Hydroxyapatite (HA) as a reinforcement. The application of PLA, PCL and HA received attention of orthopedic surgeons to accelerate the bone healing. However, the comparison between the compression strength value of these scaffolds required more investigation and advance mechanical testing. In this study, we coat the novel PCL and PLA scaffold with chitosan-HA composite to mimic with humans' body. In the next stage, the mechanical strength and the biological response of the specimen were examined. Then, the morphology and phase characterization of the materials were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) technique. The apatite formation and weight change test were performed on the porous scaffold which showed proper hydrophilicity. The microstructure of the porous scaffold was simulated using the Abaqus simulation with the extracted data from the experimental work. At the end, it was concluded that the most suitable scaffold was fabricated made of PLA filament and coated with chitosan-hydroxyapatite nanocomposite which can be useful choice for bone tissue engineering. پرونده مقاله

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3 - Design and Fabrication of Bone Scaffold Using Ceramic Composite Filament by 3D Printer
Hamideh Soleymani asl Fatemeh Kalantarzadeh Mina Alafzadeh Mojdeh Azizi Mahyar Soheily

The aging of the middle-aged portion of the population has increased the need for bone tissue scaffolds that help in healing damaged tissue. A 3D printer would be an efficient method for faster and more accurate production of bone scaffolds. This research mainly aims to چکیده کامل

The aging of the middle-aged portion of the population has increased the need for bone tissue scaffolds that help in healing damaged tissue. A 3D printer would be an efficient method for faster and more accurate production of bone scaffolds. This research mainly aims to investigate the pore configuration and the effect of two common ceramic particles (hydroxyapatite (HA) and bioactive glass) on bone scaffold production via fused deposition modeling (FDM). The scaffold building began by determining the optimal scaffold design with respect to percentage porosity and pore shape. The results show that a bone scaffold with square pores and a porosity of 20% is the optimal design. Then, composite filaments made of Polylactic acid (PLA) and the mentioned ceramic particles were prepared. Subsequently, the bone scaffold with a suitable porosity was built using the 3D printer. The results indicated that an appropriate and homogeneous composite with optimal design can constitute a suitable bone scaffold that can benefit from improved biodegradability, adequate mechanical strength, and increased bone regeneration time. پرونده مقاله

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4 - Numerical Simulation of Homogeneous, Two and Three Lattice Layers Scaffolds with Constant Density
Hamid Khanaki Sadegh Rahmati Mohammad Nikkhoo Mohammad Haghpanahi Javad Akbari

Advances in the additive manufacturing technology have led to the production of complex microstructures with unprecedented accuracy and due todesigning an effective implant is a major scientific challenge in bone tissue regeneration and bone growth. In this research, ti چکیده کامل

Advances in the additive manufacturing technology have led to the production of complex microstructures with unprecedented accuracy and due todesigning an effective implant is a major scientific challenge in bone tissue regeneration and bone growth. In this research, titanium alloy cylindrical scaffolds with three-dimensional architectures have been simulated and compared for curing partial bone deficiencies. The cylindrical networks in the scaffold (outer diameter 15 and length 30 millimeters) were designed in 36 different convergent, two-layer and three-layer types with 50% and 70% porosity. In all the samples, outer layers were denser than the inner layers. Mechanical characteristics of these scaffolds have been determined by simulating uniform compression load. The stress-strain curve of the samples showed that Young’s modulus and yield stress in the scaffolds with constant porosity were related to a unit-cell and the two-layer scaffolds, without changing Young’s modulus, had higher yield stress. This advantage was more significant in high-density scaffolds. پرونده مقاله

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5 - The Recommend of Filler Metal to Increasing the Corrosion Resistance of Gas Pipeline
Esmaeil Jafari Mohammad Sadegh Karimi

The high strength carbon steels such as API X65 is widely used to build the pipelines. In this study, the corrosion behavior welds region of the gas pipeline was studied. For this purpose, Shield Metal Arc Welding (SMAW) was used to evaluate the proposed method. The wel چکیده کامل

The high strength carbon steels such as API X65 is widely used to build the pipelines. In this study, the corrosion behavior welds region of the gas pipeline was studied. For this purpose, Shield Metal Arc Welding (SMAW) was used to evaluate the proposed method. The welding processes were performed with E6010, E6013, and ER70S-6 electrodes as filler metal and welding carried out in 3 passes by a single butt welded method. The corrosion behavior was determined in the gas fluid solution at environment temperature using potentiodynamic polarization test. The microstructure of the base metal, weld zone, and heat-affected zone were investigated with optical microscopy. Results show that the microstructure changes that formed during the welding process were correlated with electrochemical results. And the corrosion performance of the weld joints was influenced by the type of filler metal. As the welded sample with ER70S-6 has high corrosion resistance in comparison to other electrodes. پرونده مقاله

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