GCRIS Repository Collection:
https://hdl.handle.net/20.500.11851/275
2024-03-29T06:43:12Z
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Bioinspired Collagen/Gelatin Nanopillared Films as a Potential Implant Coating Material
https://hdl.handle.net/20.500.11851/9139
Title: Bioinspired Collagen/Gelatin Nanopillared Films as a Potential Implant Coating Material
Authors: Erturk, Pinar Alpaslan; Altuntas, Sevde; Irmak, Gulseren; Buyukserin, Fatih
Abstract: Collagen-based Sharpey's fibers are naturally located between alveolar bone and tooth, and they have critical roles in a well-functioning tooth such as mechanical stability, facile differentiation, and disease protection. The success of Sharpey's fibers in these important roles is due to their unique location, vertical alignment with respect to tooth surface, as well as their micronanofiber architecture. Inspired by these structures, herein, we introduce the use of nanoporous anodic aluminum oxide molds in a drop-casting setup to fabricate biopolymeric films possessing arrays of uniform Collagen: Gelatin (Col:Gel) nanopillars. Obtained structures have diameters of similar to 90 nm and heights of similar to 300 nm, yielding significantly higher surface roughness values compared to their flat counterparts. More importantly, the nanostructures were parallel to each other but perpendicular to the underlying film surface imitating the natural collagenous structures of Sharpey's fibers regarding nanoscale morphology, geometrical orientation, as well as biochemical content. Viability testing showed that the nanopillared Col:Gel films have high cell viabilities (over 90%), and they display significantly improved attachment (ca.similar to 2 times) and mineralization for Saos-2 cells when compared to flat Col:Gel films and Tissue Culture Polystyrene (TCPS) controls, plausibly due to their largely increased surface roughness and area. Hence, such Sharpey's fiber-inspired bioactive nanopillared Col:Gel films can be used as a dental implant coating material or tissue engineering platform with enhanced cellular and osteogenic properties.
2022-01-01T00:00:00Z
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Theranostic potential of graphene quantum dots for multiple sclerosis
https://hdl.handle.net/20.500.11851/9132
Title: Theranostic potential of graphene quantum dots for multiple sclerosis
Authors: Demirdogen, Birsen Can
Abstract: Nanomedicine offers great promise to solve healthcare problems using nanotechnology. Theranostics provide imaging/diagnosis and therapy simultaneously. Novel agents that target both the neuroinflammation and neu-rodegeneration component of multiple sclerosis (MS) are required. Progress has been achieved in developing smart, surface decorated nanoparticles that effectively transport the therapeutic drug into the central nervous system (CNS). Graphene quantum dots (GQDs) can be traced in vivo by fluorescence imaging due to their unique optical properties. They can also traverse the blood-brain barrier (BBB) and deliver drugs into the CNS. More-over, GQDs have low cytotoxicity and higher biocompatibility. Therefore, GQDs can be utilized to design novel multifunctional nanocarrier theranostic tools for MS.
2022-01-01T00:00:00Z
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The effect of the distance between the end point of the osteotomy and the lateral cortex on the lateral cortical hinge fracture in medial opening-wedge high tibial osteotomy
https://hdl.handle.net/20.500.11851/9084
Title: The effect of the distance between the end point of the osteotomy and the lateral cortex on the lateral cortical hinge fracture in medial opening-wedge high tibial osteotomy
Authors: Türkmen F.; Kaçira B.K.; Özer M.; Elibol F.K.E.; Bilge O.; Demir T.
Abstract: Background The purpose of this study was to compare the effects of different distances between the end point of the osteotomy and the lateral cortex on the risk of lateral cortical fracture in the medial opening-wedge high tibial osteotomy (MOWHTO) procedure. Methods Eighteen synthetic tibia models were used. Saw cuts were performed on the test models (n=6 for all groups). Wedge gap distance and wedge opening load were evaluated using compression tests. Findings The mean maximum gap distance without a lateral cortical fracture was 19.90 mm in Group 5, 15.49 mm in Group 10, and 11.23 mm in Group 15. The differences between Group 5 and Group 10, Group 5 and Group 15, and Group 10 and Group 15 were statistically significant. The mean load just before the fracture was 13.24 N in Group 5, 18.31 N in Group 10, and 26.16 N in Group 15. The difference between Group 5 and Group 15 was statistically significant. No significant difference was observed between Group 10 and both Group 5 and Group 15. Interpretation As the end point of the osteotomy is brought gradually closer to the lateral cortex, wider gaps can be opened without a lateral cortical fracture. Thus, higher angle corrections can be achieved more safely by bringing the end point of the osteotomy closer to the lateral cortex, which should be preferred to reduce the risk of a lateral cortical hinge fracture during the MOWHTO procedure, from a clinical viewpoint. © 2022
2022-01-01T00:00:00Z
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The Effect of Lateralization of a Pelvic Brim Plate on the Fixation of an Anterior Column Fracture: A Biomechanical Analysis
https://hdl.handle.net/20.500.11851/8638
Title: The Effect of Lateralization of a Pelvic Brim Plate on the Fixation of an Anterior Column Fracture: A Biomechanical Analysis
Authors: Gokgoz, Mehmet Burak; Alemdaroglu, Bahadir; Ozmeric, Ahmet; Iltar, Serkan; Erbay, Fatma Kübra; Demir, Teyfik
Abstract: Objectives Anterior column fractures can be seen as either isolated or accompanied by many types of complex acetabulum fractures. The aim of this study was to biomechanically compare the stability of a standard pelvic brim plate with a more laterally located suprapectineal plate, which is more commonly used in minimally invasive application, on an intermediate height anterior column fracture model under dynamic and static loading. Materials and methods Right side, adult, foam cortical shell artificial hemipelvis models were used (Sawbones, Pacific Research Laboratories, Vashon, WA, USA). Twenty-four (24) pieces of foam cortical shell artificial hemipelvis models were separated into three groups (M, L, and control). In group M, a suprapectineal plate was placed medially just adjacent to the pelvic brim. In group L, a laterally located suprapectineal plate was placed 2 cm lateral of the pelvic brim at its most proximal point. Then, dynamic load testing of 1000 cycles between 50 N and 500 N force and a static load test of 1.2 kN at 2 mm/minute were applied. Dynamic and static tests were conducted on an axial compression device. Displacements were measured after dynamic and static loading conditions. Results In the dynamic loading test at the AL point (superior intersection of the fracture line with the acetabular roof), the median displacement was significantly higher in group L than in group M (0.12 (IQR: 0.058-0.8125) mm and 0.04 (IQR: 0.03-0.065) mm (p = 0.02)). There was no other statistically significant difference in the displacement amounts in both dynamic and static loading conditions at other measurement points. The comparison of the stiffness of the M and L groups showed no statistically significant results, while the control group was significantly more rigid than both the M and L groups (p = 0.04 for both). None of the artificial hemipelvis models was found to be fractured at the end of the test. Conclusion Suprapectineal plates, placed on either the medial or lateral aspect of the pelvic brim, may be used for the fixation of anterior column-type fractures to provide rigid fixation and stability. As plate location did not impact stiffness and stability, the results suggest that surgeons have flexibility in determining the fixation based on accessibility, fracture pattern, and surgeon experience.
2022-01-01T00:00:00Z