Authors:Alpman MANALP; Saadet EGELİ, Yalçın İŞLER Abstract: Medical imaging is helpful to visualize body structures that cannot be seen with the naked human eye. Medical imaging techniquesare often used to diagnose patients and to follow the threatened diseases. Among these imaging techniques, x-ray-based deviceshave taken a common place. Thanks to the developing technology, flat panel detectors that allow rapid image construction in digitalradiography have been developed. Due to their high costs, these detectors are not easily available for health studies in low-incomecountries. Moreover, it is difficult to use them in studies related to education and basic research in all countries. In this study, animaging panel was designed and its initial prototype was implemented using readily-available consumer electronics components only.The cost of the proposed system is only 0.2% of the cheapest commercial alternative. This prototype panel can produce accurate imageswith 0.1mm resolution for bone-like hard tissues and 0.5mm resolution for soft tissues using the experimental setup of 70 kV and1 mAs. Hence, images obtained with the proposed panel has a moderate resolution and quality. As a result, although the developeddesign is not sufficient for medical use yet, it is a cheap alternative for educational and basic research purposes at least. PubDate: Wed, 15 Dec 2021 00:00:00 +030
Authors:Salih GÖRGÜN; Emre KOÇ Abstract: In this study, glucose-6-phospahte dehydrogenase (EC. 1.1.1.49) from the liver of Chelon auratus (Risso, 1810), an economicallyimportant mullet species, were purified with purification parameters of 252-fold purity, a specific activity of 27.04 EU/mg.proteinand a yield of 27.42%. The optimum temperature, pH and ionic strength were found to be 40 ºC, pH 8 and 0.1 M, respectively, forthe enzyme preparation obtained. The kinetic behavior of the enzyme was evaluated for both G6P and NADP+. According to thedata obtained, Km and Vmax values were determined as 0.14 mM and 3.40 EU/mL for NADP+, respectively, while it was found to be0.23 mM and 2.62 EU/mL for G6P, respectively. These data have been suggested that the enzyme has higher affinity for the NADP+,when compared with G6P as a substrate. According to the SDS-PAGE analyses of the purified enzyme, it was observed that therewere two protein bands having molecular weight of 108 kDa and 60 kDa. The results obtained have been suggested that additionalchromatographic steps might be required for the purification of glucose-6-phospahte dehydrogenase from the mullet species. PubDate: Wed, 15 Dec 2021 00:00:00 +030
Authors:Zeynep AYGUN; Murat AYGÜN Abstract: In this study, we aimed to calculate photon-matter interaction parameters of Ni80Fe15Mo5 and Ni77Fe14Cu5Mo4, which are known asmagnetic shielding alloys. The parameters were determined by using Phy-X/PSD software. The radiation attenuation parameters suchas mass attenuation coefficient, linear attenuation coefficient, effective atomic number, half-value layer, tenth-value layer, total atomiccross section and total electronic cross section were calculated between the photon energies 15keV and 100GeV in order to determinethe radiation shielding potentials of the alloys. The shielding potentials of the alloys were compared with those of widely used shieldingmaterials reported before. PubDate: Wed, 15 Dec 2021 00:00:00 +030
Authors:Berna KOÇAK; Hüseyin ÇELİKKAN Abstract: In this study, the voltammetric behavior of pendimethalin was investigated at a glassy carbon electrode (GCE) and a nafion-graphenemodified glassy carbon electrode (n-GR/GCE). The electrochemical characterization of pendimethalin was carried out using cyclicvoltammetry (CV) technique. For the determination studies performed with GCE, the differential pulse voltammetry (DPV) techniquewas employed, while the differential pulse adsorptive stripping voltammetry (DPAdSV) method was used for the determinationstudies with n-GR/GCE. First of all, optimal experimental conditions were established for both electrodes, a calibration curve wasplotted and linear working ranges were identified. For the 1st peak current of pendimethalin, the working range of the calibrationcurve drawn by DPV technique with GCE was 1.56×10-6-1.08×10-3 M with the limit of detection (LOD) value calculated as 3.09×10-5M. For the 2nd peak current of pendimethalin, the working range of the calibration curve created by DPV technique with GCE was1.56×10-6-9.73×10-4 M and the LOD value was found to be 3.36×10-6 M. For the 1st peak current of pendimethalin, the working rangeof the calibration curve constructed by DPAdSV technique with n-GR/GCE was determined to be 1.76×10-6-4.01×10-4 M with theLOD value being 8.69×10-6 M. For the 2nd peak current of pendimethalin, the working range of the calibration curve obtained byDPAdSV technique with n-GR/GCE was 1.96×10-9-7.53×10-4 M with the LOD value calculated as 1.05×10-9 M. PubDate: Wed, 15 Dec 2021 00:00:00 +030
Authors:Ahmet Muhtar ÇITIPITIOĞLU Abstract: Provisions for preloaded high strength bolt for steel element connections under seismic loads in Turkish design codes are reviewed.Ductile design is essential to achieve targeted performance levels for load bearing structural systems under seismic loads in the TurkishSeismic Code. Codes require the use of preloaded 8.8 or 10.9 high strength bolts per TS EN 14399 for the connections of elementssubjected to seismic loading. The most commonly used HR and HV type TS EN 14399 bolts are not differentiated in the codealthough their structural behavior is very different due to their geometry. HR type bolts are shaped to yield and fail in a ductile mannerunder axial loads. HV bolts have a shorter threaded length and thin nuts resulting in thread yielding and brittle thread stripping failurewhile preloading or under axial loads. Bolts failing with thread stripping during an earthquake will cause non-ductile connectionfailure. Due to risk of thread yielding and stripping which result in a connection behavior counter to seismic design principals theauthor recommends that HV type bolts not be allowed to be used in structural connections of steel elements resisting seismic loads inthe Turkish design codes. PubDate: Wed, 15 Dec 2021 00:00:00 +030
Authors:Zerrin SERT Abstract: The influence of opposing buoyancy on the laminar flow field and heat transfer characteristic is investigated across a square cylinderin a vertical channel numerically. “Opposing flow” means that the buoyancy flow and fluid motions are in opposite directions. Theworking fluids are air (Pr = 0.7) and water (Pr = 7). The flow and heat transfer simulations were changed with Reynolds number (100and 200) and under various Richardson numbers (from 0 to 0.5). The numerical analysis was carried out by Ansys-Fluent software.The effect of buoyancy was incorporated into the Navier-Stokes equations using the Boussinesq approximation. Unsteady mixedconvection heat transfer and fluid flow characteristics such as Nusselt number, Strouhal number, the drag and lift coefficient wereobtained for each case. Also, the isotherms were depicted for each simulation. It was observed that the Strouhal number, the mean dragcoefficient and Nusselt number decreased with the decrease of the Richardson number; but, CL,rms increased. PubDate: Wed, 15 Dec 2021 00:00:00 +030
Authors:Serkan SUGEÇTİ Abstract: Model insects are used as an alternative experimental model to vertebrate experimental animals in many fields such as medicine,pharmacy and veterinary medicine due to their low production cost, ethical problems and easy culture in laboratory conditions.The most common problem encountered during the production of model insects in artificial diet under laboratory conditions isbacteria, yeast and mold contamination. In this study, seven different bacterial species, four gram negative and three gram positive, wereidentified in vitro in different life stages of the model insect Galleria mellonella. As microfungus genera Alternaria spp., Aspergillus spp.,Beauveria sp., Penicillium spp. and Verticillium sp. The highest number of colonies in their life stages is defined as the species belongingto the genus Aspergillus and Penicillium, while the least belong to the genus Verticillium determined. This study is very important interms of defining microflora in artificial diet and standardizing production areas of insects under laboratory conditions PubDate: Wed, 15 Dec 2021 00:00:00 +030
Authors:Serhan HANER Abstract: The largest fields of consumption of nepheline syenite are the glass and ceramic industries. Its not containing free silica, containinghigh alkali and alumina, high melting power, and narrow melting range are ideal characteristics for the glass industry. Its field of use invarious branches of the industry and the largest reserves of this valuable raw material whose quantity is rapidly increasing are found inRussia, Canada, Norway, Brazil, China, and Turkey. Its mining in Turkey is done in the Akpınar region of Kırşehir. Akpınar-Kırşehirregion nepheline syenite is one of the smallest intrusive masses in the Central Anatolian Crystalline Karm dish spread and consistsof alkali plutonic rocks. As a result of nepheline syenite being seen as an expensive raw material other than its being accustomed toin terms of industrialists in Turkey, it is being consumed at low quantities. It has also been seen that scientific studies in an academicsense about this raw material, which has not been shown sufficient interest, are limited. The energy consumption occurring during thereduction of the particle size of the raw materials is related to the crystal structure, physical and mechanical properties of the rock. Inthis study, mineralogical, thermal, physical and mechanical properties and Hardgrove grindability of nepheline syenite in Akpınar-Kırşehir region were investigated. The mineralogical properties of nepheline syenite were determined by X-Ray diffraction (XRD) andthin section studies; The thermal properties were determined by thermogravimetric and differential scanning calorimetry (DSC/TGA)and firing color measurement. Physical properties of unit weight, water absorption rate and porosity values; Among the mechanicalproperties, Schmidt surface hardness, Ultrasonic P wave velocity and uniaxial compressive strength values were determined. In addition,the Bond work index value was calculated from the HGI value. PubDate: Wed, 15 Dec 2021 00:00:00 +030
Authors:Hüseyin YILDIRIM; Haydar ARSLAN Abstract: In this study, global optimizations of Ni6PtnCu32-n (n=0-32) ternary nanoalloys were performed by modelling interatomic interactionswith Gupta many-body potential and by Basin Hopping algorithm. Stability of nanoalloys were investigated with the excess energyanalysis and bond number analysis. The global minimum structures of all compositions obtained as a result of optimization weretaken as the initial configurations in Molecular Dynamics (MD) simulations. Melting temperatures of Ni6PtnCu32-n (n=0-32) ternarynanoalloys were investigated with the MD simulations in canonical ensemble conditions (NVT). Caloric curve and Lindemannindex were used to determine the melting transitions. As a result of MD simulations of Ni6PtnCu32-n (n=0-32) ternary nanoalloys, itwas determined that the melting temperatures fluctuate depending on the composition. Also, dynamic behaviours of the most stablecomposition obtained as a result of optimization in melting process investigated by different analysis method such as Bond-angleanalysis (BAA) and root mean square displacement (RMSD). PubDate: Wed, 15 Dec 2021 00:00:00 +030
Authors:Emel MORAL; Okan BAYRAM, Elif KÖKSAL, Fatma DANAŞ, Fethiye GÖDE Abstract: Pumpkin plant, which is among the subspecies of Cucurbitaceae family, is an agricultural product with different types and seedsare consumed. Since it is a rich source of fatty acids, pumpkin seed oil is important not only in the food industry, but also in thepharmaceutical and cosmetics industry. In this study, pumpkin seed oil was encapsulated with complex coacervation method in anexperiment set created with response surface methodology (RSM). Temperature (50.00 0C – 60.00 0C) and pH (3.80 – 4.20) wereused as independent variables in RSM, and experimentally calculated encapsulation efficiency (%EV) was used as dependent variable.The highest EV% in the experimental set 79.63% and 55.00 0C and 4.00 pH values were reached. In ANOVA results calculated forRSM; R2 = 99.44%, lack of fit p value = 0.11. The lack of fit p value (p>0.05) indicates that the model matches the data. The samplesencapsulated for each set of experiments were characterized by an optical microscope. As a result of our study, the relationship betweeninput variables and response was evaluated with the help of the literature. PubDate: Wed, 15 Dec 2021 00:00:00 +030
Open Access journal
