Browsing by Author "Yetgin S."

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Characterization of Divalent Metal Soaps of Cannabis Sativa Seed Oil
(Gazi Üniversitesi, 2023-09-01) Yetgin S.; Egbuchunam T.; Okieimen F.; Gokkus K.; Guney K.
n this study, the structural characteristics and thermal degradation behaviour of barium, calcium and zinc soaps of hemp seed oil prepared using the metathesis method are reported. Scanning electron micrographs of the metal soaps showed similar plate-like microstructures and are indicative of an orderly packed particulate structure. The bands at 1509, 1539 and 1543 cm-1 in the FTIR spectra showed the association of the carboxylate ion with Ba, Ca and Zn ions respectively The thermal decomposition consisted of one single step on the weight loss – temperature curves located around 250 – 450oC for all the divalent metal soaps at the various heating rates and the observed loss in weight which occurred before 200oC was minimal (< 10%). The average values of the apparent activation energy for the thermal process were 18.73, 13.77 and 8.48 kJ/mol for Zn-HSO, Ca-HSO and Ba-HSO respectively.
Morphology of sodium salt of calf thymus DNA on mica, alumina, and silica surfaces: Effect of solvent and drying method
(2017-06-11) Yetgin S.; Balköse D.
Investigation of morphology of deoxyribonucleotide triphosphate (DNA) dried on different surfaces by atomic force microscopy (AFM) is important in DNA research that is focused on subjects of condensation for gene therapy, sizing, DNA mapping, and cancer examination. The solvent, the surface type, and the method of drying effect the morphology of DNA on solid surfaces. Ethanol and water were used as solvents, flat mica, silica, and alumina surfaces were used as the substrates in the present study. Different methods such as ambient air-drying, N2-forced flow regime drying, and freeze-drying have been applied to droplets of DNA solutions in water or ethanol on the substrates. Forced flow drying regime causes nonlinear DNA attachment on the surface and self-assembly. DNA vertical distance on mica surface was found to be 6 and 1.4 nm for DNA dried in ambient air from ethanol and water solutions, respectively. It was 1.6 nm for N2 flow drying of aqueous DNA solution on mica surface. It was 4.6, 4.6, and 1.99 nm for ambient, N2 flow, and freeze-dried aqueous DNA on alumina surfaces, respectively. Aqueous solution of DNA dried under N2 flow on silica surface had 0.8 nm vertical distance. The smallest standard deviation of 0.05 nm was observed for DNA dried under N2 flow on alumina surface.
Thermal Behavior of the Divalent Metal Soaps of Flax, Hemp, and Safflower Seed Oils
(2022-12-07) Yetgin S.; Egbuchunam T.
This study investigated the thermal behavior of metal (barium, calcium, and zinc) soaps of flaxseed (FSO), hemp seed (HSO), and safflower (SFO) oils. The soaps were prepared by metathesis in an alcohol solution and characterized using the infrared (IR) spectroscopic technique, thermal methods, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) measurements. Features that are characteristic of specific compounds were observed from the IR graphs. The thermal behavior of the soaps was examined by simultaneous thermogravimetry, differential thermal analysis, and derivative thermogravimetry (TGA, DTA, and DTG, respectively), and it was found that degradation of the metal soaps was a multistep process: melting followed by decomposition. The percentage mass loss at various temperatures and residual mass at 600 °C were used as the indicators of the thermal stability of the metal soaps. The results showed that metal soaps obtained from different vegetable oils with the same metal ion showed differences, as did metal soaps obtained with the same vegetable oil but with different metal ions. The barium soap of SFO appeared to be more thermally stable than the other divalent metal soaps. The metal soaps show an irregular morphology with somewhat elongated plate-like structures, possibly from various multistructural groups in the soap matrix.