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Mechanical properties and cell viability of MgO-reinforced biografts fabricated for biomedical applications

Demirel M.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 4

83--90

EN

In the present study, biografts were produced by sol gel method by adding different rates of MgO which has bone-like crystal structure and high endurance into different proportions of Ca(NO3)24H2O, KOH, NaNO3, and P2O5 compounds. The biografts were investigated in terms of mechanical and biocompatibility properties. FTIR, SEM and XRD analyses were carried out to examine the chemical characteristics and changes in structural morphology. Mechanical properties were also investigated by conducting hardness and compression tests. In addition, cytotoxicity tests were conducted by using osteoblast cells. While results of FTIR and XRD analyses revealed that all biografts had HA (hydroxyapatite) and β-TCP contents, MgO peaks were also observed in biografts. In SEM images, grains of NonMgO and MgO-10 biografts had sharper edges, pores formed between grains and grain size increase with increasing MgO amount (MgO-20 and MgO-30). It was found that compression stress and hardness values increased as MgO content elevated. From the cytotoxicity tests, no any toxic effect was observed in the syntesized biografts.

2

Effect of porosity on the structure, mechanical properties and cell viability of new bioceramics as potential bone graft substitutes

Demirel M., Aksakal B.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 2

11--22

EN

Porous and alternative biografts for possible usages in orthopaedic applications were synthesized by the substitution of gelatin (G), cuttlefish backbone (C), meerschaum sepiolite (S) and hydroxyapatite (H). The effects of different proportions of the Gelatin substitutions on the mechanical properties and structure and cell viability properties of the fabricated biografts were investigated. Throughout the structure and mechanical evaluations, it was found that Gelatin substitution in the fabricated biografts increased the total porosity fraction, particularly for C13G75 and S13G75 biografts. Scanning Electron Microscope (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) were used for characterization of the synthesized biografts. Furthermore, the cell viability tests for the synthesized biografts were carried out by using the osteoblast cell culture. Throughout the analysis, the synthesized C13G75 and S13G75 biografts generated the highest porosity and better correlation between mechanical properties and structural results contributing with highest cell viability rates.

3

Factors related to presenteeism among employees of the private sector

Mandiracioglu A., Bolukbas O., Demirel M., Gumeli F.

International Journal of Occupational Safety and Ergonomics

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2015

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Vol. 21, No. 1

80--85

EN

The objective was to explore the relationship between person-based variables and work-related variables of presenteeism in four different private sector workplaces. Employees (N=413) filled in a questionnaire related to demographic and socio-economic characteristics, social networks, work-related factors, lifestyle factors and state of health. Presenteeism was assessed using the Stanford Presenteeism Scale 6 (SPS-6). The majority of respondents were male (77.2%), and mean age was 34.7±8.1 years. The prevalence of chronic conditions was 15.9%. The mean score for the SPS-6 was 19.9 (SD, 3.3). The female score was higher than the male score on the SPS-6 in this study. Total score was higher among workers who reported working at high speed. SPS-6 score was higher among individuals with a chronic health problem. Understanding of the workplace and personal factors related to presenteeism may support the health and well-being of workers.