Kerim Emre Öksüz

Bio: Kerim Emre Öksüz is an academic researcher from Cumhuriyet University. The author has contributed to research in topics: Sintering & Microstructure. The author has an hindex of 3, co-authored 23 publications receiving 41 citations. Previous affiliations of Kerim Emre Öksüz include Gazi University.

Microstructure and Hardness Characteristics of Al2O3-B4C Particle-Reinforced Cu Matrix Composites

Abstract: Copper is widely used in industrial applications because of its high electrical and thermal conductivity, easiness of processing and good corrosion resistance. However, copper also has some distinct limitations such as low hardness, low tensile yield strength and poor creep resistance. In this report copper matrix was reinforced with ceramics like Al2O3 and B4C particles using powder metallurgy (PM) method and its microstructure was examined with SEM and EDS. The microstructure has revealed an uniform distribution of particles in the matrix and a good interface bonding between B4C particles and the matrix. However the dispersion of Al2O3 particles, of larger sizes, has led to some porosity and inter-particle contacts in the composites. Therefore, hardness of B4C particlereinforced composites is significantly higher than that of Al2O3 particle-reinforced composites.

Novel natural spider silk embedded electrospun nanofiber mats for wound healing

Abstract: In recent years, electrospun nanofiber mats based on biopolymers have been extensively investigated for tissue and biomedical engineering, mainly because of remarkable morphological similarity with the natural extracellular matrix. The current study focuses on the preparation of novel natural spider silk (SS) embedded Poly(vinyl alcohol)(PVA)/Sodium alginate (NaAlg) wound dressings with desirable properties for a wound dressing application. The nanofibers' surface morphology and structure were observed by a field emission scanning electron microscope (FE-SEM). In-vivo evaluation of PVA/NaAlg based electrospun nanofiber mats as a wound dressing material and their comparison to commercially available wound dressings was carried out by in-vivo tests on rabbit models. Some morphometric parameters such as counting cells, blood vessels, endothelial cells, determination of the area of the wound closure, wound healing performance, speed of wound healing and collagen thickness were investigated using OM and FE-SEM post-processing. Furthermore, in-vitro biocompatibility and cellular behavior such as adhesion and proliferation of mouse fibroblast cells (L929) were studied by XTT assay on developed nanofiber mats. The results of this experimental study indicated that the natural spider silk embedded electrospun nanofiber mat (PVA/NaAlg/SS) accelerated the rate of wound healing compared to other groups by improving the collagen formation rate, proliferative cell activity as well as decreasing the inflammatory cell amount. Furthermore, the results of the in-vivo and in-vitro experiments suggest that novel PVA/NaAlg/SS nanofiber mats might be a fascinating bioactive wound dressing for clinical applications.

Effects of sintering temperature and addition of Fe and B4C on hardness and wear resistance of diamond reinforced metal matrix composites

Abstract: The effects of sintering temperature and addition of Fe instead of Co into the matrix composition on the mechanical properties of diamond-reinforced MMC’s have been studied. Diamond-reinforced MMC’s based on Fe-Co compositions with and without boron carbide (B4C) have been processed. Three different matrix composites (with different Fe/Co ratios) have been produced with and without B4C at a pressure of 25 MPa and sintered in N2 at various temperatures (800, 900, and 1000°C). After sintering, mechanical properties of the resultant composites have been studied and the results discussed. Addition of B4C has been found to improve the hardness and wear resistance of the composites. Optical microscopy, SEM and EDS have been used to examine the microstructure and surface of the synthesized composites.

Effect of Calcination on Microstructure Development and Properties of Hydroxyapatite Powders Extracted from Human and Bovine Bones

Abstract: This study represents a comprehensive discussion of hydroxyapatite (HAp) formation from human and bovine bones The phase formation and surface morphologies of prepared HAp powders were determined

Processing and characterization of porous SiC/NiTi alloys for biomedical applications

Abstract: NiTi shape memory alloys have attracted significant attention due to their unique shape memory effect, superelasticity, and excellent mechanical performance. In addition, the fact that NiTi alloys have high resistance to cavitation and corrosion makes them ideal candidate materials in advanced tribological and biomedical applications. The NiTi alloy composite reinforced by fine grain-sized SiC particles was successfully fabricated using powder metallurgy process. In this process, elemental Ni-Ti metal powder mixes reinforced with 0, 1, and 5 % SiC particulates were pressed uniaxial and sintered at 1100◦C in an argon atmosphere for 3 h. The effect of the SiC additions on the mechanical properties, porosity degree, and phase formation of the porous NiTi alloys was studied. After characterization, the bioactivity of the SiC/NiTi exposed samples was evaluated in simulated body fluid test. The microstructure characterization and phase identification of the apatite layer formed in SBF on their surface were also evaluated. K e y w o r d s: NiTi alloys, silicon carbide, biocompatibility, porosity, wear mechanism

Diamond and Related Materials 13 (2004) 270-276

Abstract: A new hot filament chemical vapor deposition with direct current plasma assistance (DC HFCVD) chamber has been designed for an intense nucleation and subsequent growth of diamond films on Si(100).Growth process as well as the If(V) characteristics of the DC discharge are reported. Gas phase constituents activation was obtained by a stable glow discharge between two grid electrodes coupled with two sets of parallel hot filaments settled in-between and polarised at the corresponding plasma potential. The sample is negatively biased with a small 10-15 V extraction potential with respect to the cathode grid.Such design allows to create a high density of both ions and radicals that are extracted and focussed onto the surface of the sample.The current density onto the sample can be finely tuned independently of the primary plasma.A homogeneous plasma fully covering the sample surface is visualized. Consequently, a high-density nucleation (>10 10 cm -2 ) occurs.

Marine Polysaccharides for Wound Dressings Application: An Overview.

Abstract: Wound dressings have become a crucial treatment for wound healing due to their convenience, low cost, and prolonged wound management. As cutting-edge biomaterials, marine polysaccharides are divided from most marine organisms. It possesses various bioactivities, which allowing them to be processed into various forms of wound dressings. Therefore, a comprehensive understanding of the application of marine polysaccharides in wound dressings is particularly important for the studies of wound therapy. In this review, we first introduce the wound healing process and describe the characteristics of modern commonly used dressings. Then, the properties of various marine polysaccharides and their application in wound dressing development are outlined. Finally, strategies for developing and enhancing marine polysaccharide wound dressings are described, and an outlook of these dressings is given. The diverse bioactivities of marine polysaccharides including antibacterial, anti-inflammatory, haemostatic properties, etc., providing excellent wound management and accelerate wound healing. Meanwhile, these biomaterials have higher biocompatibility and biodegradability compared to synthetic ones. On the other hand, marine polysaccharides can be combined with copolymers and active substances to prepare various forms of dressings. Among them, emerging types of dressings such as nanofibers, smart hydrogels and injectable hydrogels are at the research frontier of their development. Therefore, marine polysaccharides are essential materials in wound dressings fabrication and have a promising future.