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Öğe A universal self-eroding sacrificial bioink that enables bioprinting at room temperature(Wiley, 2020) Aydın, Levent; Küçük, 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; Aydın, Levent; Küçük, Serdar; Özkoç, Güralp; Çetinarslan, Berrin; Cantürk, 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-Institute of Electrical and Electronics Engineers Inc., 2019) Ege, Mücahit; Küçük, 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 Diyabetik bireylerde katkılı üretim teknolojileri ve termoplastik elastomer temelli ayak ülserlerini önleyici medikal tabanlık geliştirilmesi ve biyomekanik validasyonu(Institute of Electrical and Electronics Engineers Inc., 2019) Aydın, Levent; Küçük, Serdar; Çetinarslan, Berrin; Cantürk, Zeynep; Peker, Ayfer; Ege, Mücahit; Yalçın, FatihGeleneksel yöntemlerle tabanlık üretimi oldukça yorucu ve beceri gerektiren bir iştir. Bu üretim sürecinde görev alan uzmanlar alçı, karbon ve köpük gibi malzemelerin tozlarına önemli ölçüde maruz kalmaktadır. Ayrıca, geleneksel üretilen medikal cihazların seri üretilen bir ayakkabı içerisinde amacına uygun olarak kullanılabilmesi her durumda mümkün olmamaktadır. Bu çalışmada diyabetik bireylerde kullanılmak üzere FDM sistemi ile çalışan bir katkılı üretim teknolojisi ve termoplastik elastomer temelli ayak ülserlerini önleyici medikal tabanlık geliştirilmiştir. Biyomekanik işlevselliğin uygunluğunun denetlenebilmesi için polimer analizlerinden elde edilen ölçümlerden yararlanılmıştır. Son olarak, sonlu eleman analizi ile hastaya özgü biyomekanik validasyon gerçekleştirilerek arzu edilen biyomekanik işlevselliği sağlayan üretim parametreleri belirlenmiştir. Katkılı ve geleneksel üretilen tabanlıklar ayrıca zaman, maliyet ve fonksiyonellik açısından karşılaştırılmıştır.Öğe Elektronik kontrollü diz üstü protez bacağın model tasarımı(Institute of Electrical and Electronics Engineers Inc., 2015) Ege, Mücahit; Küçük, SerdarBu çalışma ile elektronik kontrollü diz üstü protez bir bacağın mekanik model tasarımı çıkarılmıştır. Bunun için ilk olarak yürüme analizi verileri elde edilmiştir. Elde edilen verilere dayanarak sistemin mekanik modeli tasarlanmıştır. Model tasarımında elektronik kontrollü protez bir bacak için ergonomik yapı, boy, ağırlık, enerji tüketimi, hız, tork ve elektromekanik kontrol gibi parametrelerin çok önemli olduğu görülmüş ve tasarımlar bu doğrultuda gerçekleştirilmiştir. Mevcut literatürde üretim ve kontrolü kolay olması nedeniyle genellikle düz zemin koşullarında diz ve ayak bileği üzerinde çalışmalar yapılmıştır. Farklı zemin koşullarında yürüme kabiliyeti kazandırmak için tasarımda ayak bileğine ikinci bir eksen hareketi eklenerek ayak inversiyonu ve eversiyonu sağlanmıştır. Ayrıca diz ve ayak bileğine ek olarak ayak parmağı eklemi eklenerek kullanıcı için yürüme rahatlığı ve estetik yürüme kabiliyeti elde edilmesi amaçlanmıştır. Bu tasarımlara dayanarak sistemin ileri yön kinematiği çıkarılmış ve yürüme esnasında konum ve yönelim verileri elde edilmiştir.Öğe Energy minimization of new robotic-type above-knee prosthesis for higher battery lifetime(MDPI, 2023) Ege, Mücahit; Küçük, 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 Omurga cerrahisinde ameliyat planlama ve optimizasyon(IEEE-Institute of Electrical and Electronics Engineers Inc., 2019) Ege, Mücahit; Küçük, Serdar; Çakır, Özgür; Aydın, Levent; Dilek, Rıza; Konuk Ege, GözdeÜç boyutlu tarama teknolojileri, anatomik modeller, biyouyumlu implantlar ve ortotik/protez modeller gibi tıbbi ihtiyaçlar için yaygın şekilde kullanılmaya başlamıştır. Ancak taranan dokuların üç boyutlu görsellerinin iki boyutlu bilgisayar ekranları kullanılarak görüntülenmesi istenilen etkiyi verememektedir. Sanal gerçeklik teknolojisi ile yapılan cerrahi planlama daha kesin sonuçlar sunuyor olsa da yüksek maliyetler nedeniyle her hastanede uygulanamamaktadır. Bu çalışmada ileri derece bir skolyoz hastasının ameliyat işlemi önceden planlanarak, özellikle kompleks omurga ameliyatlarında kullanılmak üzere ideal bir protokol belirlenmiş ve hedef anatomik doku yapısına uygunluğu analiz edilmiş olup bahsedilen anatomik modelin üretimini gerçekleştirecek katmanlı üretim teknolojileri tabanlı bir ameliyat planlama sistemi ortaya konmuştur.Öğe Trajectory planning of electronically controlled prosthesis by using third-order polynomial(IEEE-Institute of Electrical and Electronics Engineers Inc., 2017) Ege, Mücahit; Küçük, Serdar; Memişoğlu, 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.
