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Öğe A universal self-eroding sacrificial bioink that enables bioprinting at room temperature(Wiley, 2020) Aydin, Levent; Kucuk, Serdar; Kenar, HalimeNatural polymer-based hydrogel bioinks are widely used in bioprinting due to their suitability for recapitulation of in vivo cellular activities. However, preservation of the target geometry in a cell-laden hydrogel is difficult to achieve. The aim of this study was to develop a universal sacrificial bioink that allows high cell viability and a better shape fidelity in the cell-laden construct. A polysaccharide-based universal sacrificial bioink was developed for microextrusion-based bioprinting and was optimized to erode in 48 hours in the cell culture medium without formation of any undesired by-products. The sacrificial hydrogel was prepared from alginate and agarose via a microwave oven assisted method and bioprinted at room temperature to generate microchannels in the cell-laden hydrogel or to support a tubular structure and its biocompatibility determined by live/dead assay. Bioprinting time was significantly reduced, down to a few minutes for a large-scale tissue model (1 minute 52 seconds for a 2 cm tubular structure), by means of a high bioprinting speed up to 25 mm/s. After 48 hours in the cell culture, the sacrificial bioink completely detached from the cell-laden construct without causing any changes in its printed shape. Cell viability in the cell-laden construct was observed to be more than 95% at the end of 3-day culture. This novel sacrificial bioink enables bioprinting at room temperature without affecting oxygen and nutrient penetration into the cell-laden hydrogel and allows retention of high cell viability and shape fidelity.Öğe Additive manufacturing and biomechanical validation of a patient-specific diabetic insole(Wiley, 2020) Peker, Ayfer; Aydin, Levent; Kucuk, Serdar; Ozkoc, Guralp; Cetinarslan, Berrin; Canturk, Zeynep; Selek, AlevCenters for Disease Control and Prevention (CDC) has reported that lower extremity amputation (LEA) rate of per 1000 diabetic patients is 18.4 because of the complications that first appeared in the foot. A second amputation is also required for 9% to 17% of these patients within the same year although LEA may be preventable. Most of the diabetic foot conditions may be prevented and treated by a therapeutic footwear or a medical device such as an insole or an orthotic shoe. Traditional insole manufacturing is a laborious work that requires specific skills. Moreover, traditional approaches contain harmful material particles that may cause respiratory failure. Unfortunately, manufactured insoles may not be suitable for any mass-produced footwear in all cases. Therefore, patient requires to get insole-specific footwear. In this study, a diabetic insole was manufactured by means of a fused deposition modeling-(FDM) based system and a thermoplastic polymer. Biomechanical functionality was determined according to the applied polymer analysis on each produced sample and foam material. Subsequently, finite element analysis (FEA) was performed to target insole geometry to ensure the quality of the final medical product. Additive and traditional manufactured insoles are compared according to the cost and function. As a result, fabrication of an insole, based on the FDM method, was improved down to 8 h and 9 m. The weight of an insole prototype was 74.74 g, and the material cost was $3.44 while total cost of the traditional foam casting was determined as $35.37 and weight of the insole was 72.6 g for this study. Consequently, benefits of the applied method are evaluated.Öğe Design and Dynamic Model of A Novel Powered Above Knee Prosthesis(IEEE, 2019) Ege, Mucahit; Kucuk, SerdarNowadays, fully active lower limb prostheses are very important for amputees to have comfort, aesthetic mobility and the ideal adaptation to daily life. However, active joint control is very difficult because of changing floor conditions, and it is essential to obtain a dynamic model of prostheses for system control. In this study, the design and dynamic model of a new above-knee prosthesis are presented. Firstly, the model design of the prosthesis was proposed by using Solidworks software environment and then kinematic and dynamic model was obtained as mathematical by using both Lagrange-Euler and also Newton-Euler method. The accuracy of the results has been proved with the same results obtained by both methods. MATLAB and Scientific Notebook software were used for those calculations. The torque equations required were obtained to perform joint movements with the dynamic model calculations and a simulation was performed to demonstrate the torques required for a gait cycle. Torque equations obtained were used for system control, motors selection and optimization in other studies.Öğe DESIGNING OF A MODEL OF ELECTRICAL CONTROLLED ABOVE KNEE PROTHESIS(IEEE, 2015) Ege, Mucahit; Kucuk, SerdarIn this study, a mechanical model of electrically controlled above knee prosthesis was designed. Since the parameters such as ergonomic structure, height, weight, energy consumption, velocity, torque and electromechanical control are very important for prosthesis, the new prosthesis was designed considering these parameters. In literature, studies are mostly performed in flat surfaces because of straight forwardly designing and manufacturing above knee prosthesis. However in this study, a universal joint that provides foot inversion and eversion was added to the ankle in order to make the prosthesis to walk different surface conditions. Likewise a toe joint was also mounted for achieving walking convenience and aesthetics. Finally, forward kinematics model was derived and position and orientation data was obtained during the walking.Öğe Development And Biomechanical Validation Of Medical Insoles To Prevent Foot Ulcers On Diabetic Patients By Means Of Thermoplastic Elastomers And Additive Manufacturing Technologies(IEEE, 2019) Aydin, Levent; Kucuk, Serdar; Cetinarslan, Berrin; Canturk, Zeynep; Peker, Ayfer; Ege, Mucahit; Yalcin, FatihTraditional insole manufacturing, also known as customized medical equipment production, is a laborious work that requires specific skills. Current manufacturing approach contains harmful material particles such as plaster and carbon that may cause respiratory failure. Besides, manufactured insoles may not be suitable for any mass-produced footwear in all cases. Therefore, patients require to get insole-specific footwears. In this study, a diabetic insole was manufactured using a thermoplastic elastomer on an FDM based system. Biomechanical functionality was achieved by means of the performed polymer analysis. Finally, desired biomechanical properties were determined by performed finite element analysis. Both additive and traditional manufactured insoles were also compared according to the cost and function.Öğe Energy Minimization of New Robotic-Type Above-Knee Prosthesis for Higher Battery Lifetime(Mdpi, 2023) Ege, Mucahit; Kucuk, SerdarIn this paper, an optimization problem for the energy minimization of a new robotic-type three-axes above-knee prosthesis is carried out based on the actuator power consumption. The optimization problem aims to find the optimal link masses with which to minimize the electrical energy drawn from the battery of the new prosthesis, subject to the kinematic and dynamic constraints. Particle swarm optimization (PSO) is used as the optimization algorithm. A discrete-time PID controller is used to represent the saved energy by means of mass optimization. Optimization illustrated that energy consumption in the batteries can be reduced 51% and provides 1.89 h of additional battery lifetime, according to the literature, by optimizing prosthetic link masses while providing acceptable prosthesis stiffness.Öğe Patient specific cardiovascular disease modelling based on the computational fluid dynamics simulations: segmentation and hemodynamic model of a thoracic artery(2020) Aydın, Levent; Kucuk, Serdar; Cakır, OzgurNowadays cardiovascular diseases (CVDs), mostly coronary artery diseases become a leading cause of death. Flow dynamics of a vessel is important to diagnose a CVD in advance. However, hemodynamic parameters may not be measured directly. Hence, computational methods are increasingly being used in the fields of neurosurgery and cardiovascular surgery to obtain realistic physiological simulations. In this study, a patient specific thoracic artery model is first segmented based on the MRI images and then a thoracic aneurysm disease model is simulated to assess blood flow changes under the predefined conditions.Öğe Surgical Planning and Optimization of A Full Spine Surgery(IEEE, 2019) Ege, Mucahit; Kucuk, Serdar; Cakir, Ozgur; Aydin, Levent; Dilek, Riza; Ege, Gozde Konuk3D scanning technologies have become widely used for medical needs such as anatomical models, biocompatible implants and orthotic / prosthetic models. However, the use of 3D visuals of the scanned tissues using two-dimensional computer screens cannot give the desired effect. Although surgical planning with virtual reality technology provides more accurate results, it cannot be performed in every hospital due to high costs of the system. In this study, the operation of an advanced scoliosis patient was planned in advance. An ideal protocol to be used especially in complex spine operations was determined and its suitability to the target anatomical tissue structure was analyzed. At the same time, a surgical planning system based on layered manufacturing technologies to realize the production of the mentioned anatomical model is introduced.Öğe Trajectory Planning of Electronically Controlled Prosthesis by Using Third-Order Polynomial(IEEE, 2017) Ege, Mcahit; Kucuk, Serdar; Memisoglu, KayaIn this study, the mechanical model of the electronically controlled knee prosthesis is developed, forward and inverse kinematic analyses are performed, and trajectory tracking for joint space is obtained, respectively. The analyses were carried out considering a cycle of gait walking at a constant speed. Thus, position, velocity and acceleration data of the prosthesis of joint space required for the control of the prosthesis is obtained.
