Ayhan Oral

The diatomaceous earth (DE), collected from the Mariovo region in North Macedonia, was characterized and thermally modified. The material represents a sedimentary rock of biogenic origin, soft solid that can be easily disintegrated, with white to grayish color, with bulk density of 0.51–0.55 g/cm3, total porosity of 61–63%, and specific gravity of 2.25 g/cm3. The chemical composition is as follows: SiO2, 86.03; Al2O3, 3.01; Fe2O3, 2.89; MnO, 0.06; TiO2, 0.20; CaO, 0.76; MgO, 0.28; K2O, 0.69; Na2O, 0.19; P2O5, 0.15; and loss of ignition, 5.66 (wt%). The mineralogy of the raw DE is characterized by the predominant presence of amorphous phase, followed by crystalline quartz, muscovite, kaolinite, and feldspar. Significant changes in the opal phase are observed in the 1,000–1,200°C temperature region. At 1,100°C, the entire opal underwent solid–solid transition to cristobalite. Further ramp of the temperature (1,100–1,200°C) induced formation of mullite. Scanning electron microscopy (SE...

This study investigated the production of poly(lactic acid) (PLA) nanofibers containing cypress (CUP) essential oil (EO) via electrospinning. The nanofibers were produced from polymer solution prepared with different percentages of cypress EO. Cypress EO-containing PLA nanofibers were characterized and some mechanical and thermal properties were examined using thermogravimetric analysis, scanning electron microscopy, Fourier-transform infrared spectroscopy, and dynamic mechanical analysis. The thermal stability of the nanofibers was reduced depending on the percentage of the cypress EO. As the ratio of the cypress EO to polymer matrices was increased, it was observed that the glassy transition temperatures of the nanofibers decreased and their flexibility increased. The T g value was determined to be 53.74°C for the neat PLA nanofiber, while 51.83°C for the PLA-CUP nanofiber (containing 15% cypress EO). According to the results of releasing trial, the increased amount of cypress EO ...

Pteropods are marine pelagic calcifier mollusks sensitive to chemical changes in seawater due to their highly soluble aragonite shells. Increased acidity (reduced pH) of seawater causes difficulties in precipitating their shells and/or results in their dissolution, which is related to increased atmospheric CO2 concentrations and warming of seawater. They are therefore indicators of environmental changes. In this paper, we present the first record of the straight-needle pteropod Creseis acicula Rang, 1828 bloom in the surface waters of the Ҫanakkale Strait, Turkey (NE Aegean Sea), encountered in July 2020, when the highest sea surface temperatures and pH levels since 2007 were recorded. In coastal zones, such as the Ҫanakkale Strait, anthropogenic activity contributes significantly to environmental changes. Consequently, the increase in pH at elevated temperatures indicates an auxiliary factor (i.e. anthropogenic activity) that triggered the C. acicula bloom, rather than global atmos...

The objective of this work was to evaluate antibacterial and antibiofilm activity of Eucalyptus camaldulensis EO-loaded PLA nano-fibers. Different concentrations of E. camaldulensis EO (7.5, 10 and 15%) were incorporated into PLA nanofibers via an electrospin-ning technique. The nanofibers are characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA). Antibacterial activity of essential oil-loaded PLA nanofibers against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis were investigated by disc diffusion method. The antib-iofilm activity of essential oil-loaded PLA nanofibers was studied against Pseudomonas aeruginosa. The results obtained from the biofilm formation test revealed that PLA essential oil inhibited the Pseudomonas aeruginosa biofilm by 9.3%, 12.8% and 12.6%, respectively. Drug releasing behavior of essential oil-loaded PLA nanofibers was investigated by UV-Visible spectroscopy. According to releasing results, as the amounts of Eucalyptus camaldulensis essential oil in PLA nanofibers increased, the releasing decreased. The essential oil-loaded PLA nanofiber successfully delivered about 160 h.

Gold (Au) and silver (Ag) nanostructures have widespread utilization from biomedicine to materials science. Therefore, their synthesis with control of their morphology and surface chemistry have been among the hot topics over the last decades. Here, we introduce a new approach relying on sugar derivatives that work as reducing, stabilizing, and capping agents in the synthesis of Au and Ag nanostructures. These sugar derivatives are utilized alone and as mixture, resulting in spherical, spheroid, trigonal, polygonic, and star-like morphologies. The synthesis approach was further tested in the presence of acetate and dimethylamine as size- and shape-directing agents. With the use of transmission electron microscopy (TEM), selected area electron diffraction (SAED), x-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) absorption spectroscopy techniques, the particle size, shape, assembly, aggregation, and film formation characteristics were evalu...

The main goal of this study is to prepare antibacterial poly(lactic acid) (PLA) containing cinnamaldehyde and geraniol and to evaluate the antibacterial activity and assess the changes of physical properties of the PLA films. Cinnamaldehyde- and geraniol-incorporated (10%, 20%, 30%, and 50% v/w) PLA films were prepared via solution-casting. While preparing these films, plasticizers were not added to the matrix. Antibacterial activities of these films against Escherichia coli and Staphylococcus aureus were investigated by the disk diffusion method. Thermal degradation characteristics were analyzed via thermogravimetric analysis (TGA), glass transition, crystallization, and melting temperatures, and enthalpies of the films were determined from differential scanning calorimetry (DSC) scans. Tensile strength and elongation-at-break values of neat PLA and antibacterial-compound-containing films were evaluated and compared after the mechanical tests. Moreover, the changes in the polymer m...

Recently, polylactic acid which is in the family of biodegradable polymers, has been used in various areas in industry due to having such properties as short degradation time, leaving no harmful residuals after degradation and being obtained from renewable resources. Packaging industry is the one of the important application areas of polylactic acid. Polylactic acid has been preferred extensively for food packaging applications due to its green polymer properties. These packaging materials haveto conserve the food products from outer contaminations. Besides, decomposition of foods by bacteria is a very important case for food safety as well. Harmful bacteria such as E. coli, S. aureus can cause foods decomposition and also causes foodborne illness to people and animals. So, nowadays antibacterial effect is among the demands from food package material’s features to avoid bacteria’s bad effects. Therefore in this study, cinnamaldeyhe as an antibacterial was added to polylactic acid an...

Some studies emphasized that anatomic mechanisms of vertebral aberrations could be associated with large breasts. The effect of mammaplasty operation on the vertebral column and body posture seems to be beneficial; in this trial, it was planned to investigate the objective radiologic effect of reduction mammaplasty on the posture of the vertebral column in a group of patients operated due to the large breasts. Thirty-four white women with large breasts were enrolled in this study. The patients were divided into three groups according to their breast cup sizes. Anteroposterior and lateral radiographs of the lumbosacral and thoracic spine were taken at baseline preoperatively, and the same radiographic images were taken in an average of 12 months later than the reduction mammaplasty operation. All were evaluated and compared for thoracic kyphosis angle and lumbar lordosis angle both preoperatively and postoperatively. The mean thoracic kyphosis angle was 40,53 preoperatively and 39,38...

Random poly(ethylene terephthalate-co-sebacate) (PETS) is a typical copolyester comprising aromatic polyester poly(ethylene terephthalate) (PET) and aliphatic polyester poly(ethylene sebacate) (PES). Copolymerization endows the resulting products PETS with modified ...