Publications by authors named "Tugba Onal Okyay"

In the present study, highly effective and reusable monodisperse ruthenium-nickel (Ru-Ni) nanomaterials supported on poly(N-vinyl-2-pyrrolidone) (Ru-Ni@PVP) were synthesized (3.51 ± 0.38 nm) by a facile sodium-hydroxide-assisted reduction method; Ru and Ni reduction in PVP solution was accomplished.

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Addressed herein, functionalized multi-walled carbon nanotube (MWCNT) supported highly monodisperse nickel nanoparticles modified on glassy carbon electrode (Ni@f-MWCNT/GCE) were synthesized through microwave assisted method and examined for non-enzymatic glucose sensing in ionic liquids by cyclic voltammetry and chronoamperometry. The results of Ni@f-MWCNT/GCE electrode were compared with Ni NPs/GCE electrode and the results revealed that f-MWCNTs increased the electrocatalytic properties of Ni nanoparticles regarding glucose oxidation. They also demonstrated a good linear span of 0.

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In this study, CO2 sequestration was investigated through the microbially-induced calcium carbonate precipitation (MICP) process with isolates obtained from a cave called 'Cave Without A Name' (Boerne, TX, USA) and the Pamukkale travertines (Denizli, Turkey). The majority of the bacterial isolates obtained from these habitats belonged to the genera Sporosarcina, Brevundimonas, Sphingobacterium and Acinetobacter. The isolates were investigated for their capability to precipitate calcium carbonate and sequester CO2.

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In real environmental applications, such as heavy metal bioremediation, microorganisms are generally not kept at their optimum growth conditions; therefore, it is imperative to investigate their heavy metal removal performance under diverse environmental conditions. The present study aims to investigate the effects of pH, temperature and growth phases on the removal of Cu(2+) and Cr(6+) by two environmental isolates identified as Ochrobactrum intermedium LBr and Cupriavidus metallidurans CH34. Results showed that cells in logarithmic phase presented better biosorption capacity than cells in stationary phase for both isolates.

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A novel high throughput colorimetric urease activity assay was compared to the Nessler method. The new method employs phenol red to determine the urease activity. This method reduces significantly sample processing time and allows real-time investigations.

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