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Demirci S.,Bilkent University | Demirci S.,Klrlkkale University | Avazll N.,Bilkent University | Durgun E.,Bilkent University | Cahangirov S.,Bilkent University
Physical Review B - Condensed Matter and Materials Physics | Year: 2017

We investigate the structural, mechanical, and electronic properties of the two-dimensional hexagonal structure of group III-VI binary monolayers, MX (M=B, Al, Ga, In and X=O, S, Se, Te) using first-principles calculations based on the density functional theory. The structural optimization calculations and phonon spectrum analysis indicate that all of the 16 possible binary compounds are thermally stable. In-plane stiffness values cover a range depending on the element types and can be as high as that of graphene, while the calculated bending rigidity is found to be an order of magnitude higher than that of graphene. The obtained electronic band structures show that MX monolayers are indirect band-gap semiconductors. The calculated band gaps span a wide optical spectrum from deep ultraviolet to near infrared. The electronic structure of oxides (MO) is different from the rest because of the high electronegativity of oxygen atoms. The dispersions of the electronic band edges and the nature of bonding between atoms can also be correlated with electronegativities of constituent elements. The unique characteristics of group III-VI binary monolayers can be suitable for high-performance device applications in nanoelectronics and optics. © 2017 American Physical Society.

Yumusak E.,Klrlkkale University | Ornek K.,Klrlkkale University | Durmaz S.A.,Klrlkkale University | Guler H.A.,Klrlkkale University
BMC Ophthalmology | Year: 2016

Background: Excessive weight is a well-known risk factor for microvascular diseases. Changes in thickness in a vascular tissue, such as the choroid, can be useful to evaluate the effect of obesity on the microvascular system. The aim of this study was to evaluate the choroidal thickness (CT) changes in obese women, using optical coherence tomography (OCT). Methods: The prospective clinical study included examination of the right eyes of 72 patients. The right eyes of 68 patients were examined and served as the controls. A complete ophthalmological examination and OCT imaging were performed for each group studied. The CT in each eye was measured using OCT. Results: The obese group consisted of 72 female patients with a mean age of 37.27 ± 1.18 years. The control group included 68 female subjects with a mean age of 37.85 ± 7.98 years (p > 0.05). There was no statistical significant difference for the foveal retinal thickness measurements between the two groups (p > 0.5). Our study revealed significant choroidal tissue thickening subfoveally and at areas 500 μm temporal, 500 μm nasal, and 1500 μm nasal to the fovea in the obese group (all p < 0.05). There was a positive correlation between body mass index (BMI) and CT changes. Conclusions: CT may increase in obese women and a positive correlation was found between BMI and CT. The trial protocol was approved by the Local Ethical Committee of the Klrlkkale University, date of registration: April 27, 2015 (registration number: 10/11). © 2016 Yumusak et al.

Akbas H.,Gaziosmanpaşa University | Okumus A.,Ankara University | Karada A.,Gaziosmanpaşa University | Klllc Z.,Ankara University | And 5 more authors.
Journal of Thermal Analysis and Calorimetry | Year: 2016

The salicylic acid salts of fully substituted mono(4-fluorobenzyl)spirocyclotriphosphazenes (10-15) were prepared. The structures of these phosphazenium salts (10a-15a) were determined by elemental analyses, FTIR and 1H, 13C{1H}, 31P{1H} NMR techniques. The crystal structure of 14a was verified by X-ray diffraction analysis. The thermal properties of the salts were investigated using TG/DTA and DSC instruments. The results obtained from DSC indicated that the melting temperatures and latent heats of the compounds were in the ranges of 107.76-143.04 °C and 41.64-69.73 J g-1, respectively. The thermal stabilities of the phosphazenium salts (10a-15a) are found to be different, but they have a similar decomposition mechanism. The compounds 14a and 15a exhibit noticeable cytotoxic activity against DLD-1 cancer cells, and they seem to be good candidates for being anticancer agents. All of the compounds have an antimicrobial effect on bacterial and yeast strains within the ranges of 312-625 μM (bacterial strains) and 19.5-312 μM (yeast strains). It is found that compounds 13a-15a were most effective against yeast strains. Moreover, interactions between the salts and pBR322 plasmid DNA show that 14a and 15a cleave the DNA and decrease the intensity of form I. BamHI and HindIII digestion results demonstrate that the compounds are not bound with G/G and A/A nucleotides, respectively. © 2015 Akadémiai Kiadó, Budapest, Hungary.

Yumusak E.,Klrlkkale University | Yumusak E.,Kirikkale University | Dikel N.H.,Klrlkkale University | Ornek K.,Klrlkkale University
BMC Ophthalmology | Year: 2015

Background: The aim of this study was to investigate the potential significance of the central macular thickness (foveal thickness-FT) and choroidal thickness (CT) in the eyes of patients with iron-deficiency anemia, the most common form of the anemia, via enhanced-depth imaging optical coherence tomography (EDI-OCT). We also investigated whether such changes might serve as an early indicator of underlying hematological disease. Methods: This prospective clinical study compared 96 female patients with iron-deficiency anemia and 60 healthy female control subjects. The macular and choroidal thicknesses in the temporal and nasal subfoveal areas were measured using enhanced-depth imaging optical coherence tomography (EDI-OCT) at 500 and 1500 microns and in five different regions (FCT, T1500, T500, N500, and N1500). Results: The mean ages of the patients and healthy controls were 34.08 ± 10.39 years and 32.29 ± 8.28 years, respectively (P =0.232). There were no significant changes in macular thickness between the groups (225.58 ± 19.76 vs. 222.45 ± 13.51, P =0.2). The choroidal thickness was significantly reduced in the patient group relative to the controls at all measured points (foveal choroidal thickness, P = 0.042; nasal-500 microns, P = 0.033; temporal-500 microns, P = 0.033; and temporal-1500 microns, P = 0.019). At some points, the choroidal thickness findings correlated with the hemoglobin values (temporal-500 microns, r = -0.287, P = 0.001; nasal-500 microns, r = -0.287, P = 0.005; nasal-1500 microns, r = -0.245, P = 0.016; and temporal-1500 microns, r = -0.280, P = 0.06). Conclusions: Patients with iron-deficiency anemia had a significantly reduced choroidal thickness. © 2015 Yumusak et al.

Onbasilar E.E.,Ankara University | Unal N.,Ankara University | Erdem E.,Klrlkkale University | Kocakaya A.,Ankara University | Yaranoglu B.,Ankara University
Poultry Science | Year: 2014

The aim of this study was to investigate the differences in production performance, use of nest box, and external appearance of 2 strains of laying hens kept in conventional and enriched cages. Lohmann Brown Classic (LB, n = 532) and Lohmann LSL Classic (LW, n = 532) hens were housed from 16 to 73 wk in either conventional cages or enriched cages. Enriched cages had a nesting area, scratch pad, perch, and nail shortener. Body weight (BW), hen-day egg production, egg weight, feed intake, feed conversion ratio (FCR), cracked and dirty eggs, use of nest box for lay, and external appearance were determined. Laying period influenced the hen-day egg production, egg weight, feed intake, and feed conversion ratio. Cage type affected the hen-day egg production and feed conversion ratio, while strain affected the egg weight, feed intake, and feed conversion ratio. Laying period × cage type and laying period × strain interactions affected egg production, egg weight, and feed conversion ratio. Both strains preferred to lay in the nest box. Percentages of cracked and dirty eggs of LW hens in enriched cages were higher than that in conventional cages. Most of the dirty eggs laid by both strains were found outside of the nest box. The LW hens laid more dirty eggs than the LB hens. Cage type and cage type × strain interaction were important for total feather score. Final claw length was affected by cage type, strain, and cage type × strain interaction. This study suggests that cage type, strain, and also cage type × strain and period × strain interactions should be considered when alternative housing systems are used. © 2015 Poultry Science Association Inc.

Yildiz E.,Klrlkkale University | Aydin A.,Klrlkkale University | Sarpun !.H.,Afyon Kocatepe University | Tel E.,Osmaniye Korkut Ata University
EPJ Web of Conferences | Year: 2015

The cross sections and astrophysical S-factors of the 63Cu(α,γ) and 63Cu(α,n) reactions have been calculated. The radiative alpha capture reaction cross sections was calculated in the incident energy range of 3 to 10 MeV and the (α,n) reaction cross sections was calculated in the incident energy range of 7 and 16 MeV. In these theoretical calculations, the TALYS 1.6 and NON-SMOKER codes were used. Also for these reactions, it was calculated the astrophysical S-factors which describe the possibility of reaction in low energies. Obtained results were compared to the experimental data taken from EXFOR database. © 2015 Owned by the authors, published by EDP Sciences.

Bayrak H.,Elektronik Muhendisligi Bolumu | Nur Yilmaz G.,Klrlkkale University
2016 24th Signal Processing and Communication Application Conference, SIU 2016 - Proceedings | Year: 2016

3-Dimensional (3D) Video Quality Assessment (VQA) has been an important area for researchers working in this area. The reason is there isn't any well accepted and standardized VQA method for 3 Dimensional (3D) as for 2-Dimensional (2D) video. Depth perception assessment (DPE) is the most critical part of 3D VQA because of visual realism. Subjective tests are currently in use for the 3D VQA because there aren't any 3D VQA algorithms for measuring this perception accepted by researchers in literature. Subjective tests are not ergonomic methods from the stand point of time and cost. Therefore, it is quite important to develop objective 3D VQA metrics for predicting the depth perception of users. The VQA algorithms developed without using a reference video is called No-Reference (NR) metrics in literature and they are considered efficient compared to the other metrics. In this study, Depth Maps (DM) in 2D+depth based 3D videos are utilized to measure Structural Average Depth (SAD) in a NR manner. The results of this study presents that the YOD algorithm can be considered as a part of a 3D VQA metric assessing the depth perception and approved by researchers. © 2016 IEEE.

Yilmaz S.,Klrlkkale University | Adisen M.Z.,Klrlkkale University | Misirlioglu M.,Klrlkkale University | Yorubulut S.,Klrlkkale University
Medical Principles and Practice | Year: 2016

Objectives: The purpose of this study was to assess the pattern of third molar impaction and associated symptoms in a Central Anatolian Turkish population. Material and Methods: A total of 2,133 impacted third molar teeth of 705 panoramic radiographs were reviewed. The positions of impacted third molar teeth on the panoramic radiographs were documented according to the classifications of Pell and Gregory and of Winter. The presence of related symptoms including pain, pericoronitis, lymphadenopathy and trismus was noted for every patient. Distributions of obtained values were compared using the Pearson χ2 test. Nonparametric values were analyzed using the Mann-Whitney U test and Kruskal-Wallis test. Results: The mean age of the subjects was 30.58 ± 11.98 years (range: 19-73); in a review of the 2,133 impacted third molar teeth, the most common angulation of impaction in both maxillaries was vertical (1,177; 55%). Level B impaction was the most common in the maxilla (425/1,037; 39%), while level C impaction was the most common in the mandible (635/1,096; 61%). Pain (272/705; 39%) and pericoronitis (188/705; 27%) were found to be the most common complications of impaction. Among 705 patients (335 males, 370 females), pericoronitis was more prevalent in males (101; 30%) and usually related to lower third molars (236; 22%). The retromolar space was significantly smaller in females (p < 0.05). Moreover, there was a significant difference in retromolar space for the area of jaw (maxillary: 11.3 mm; mandibular: 14.2 mm) and impaction level (A: 14.7 mm; B: 11.1 mm; C: 10.3 mm; p < 0.05). Conclusion: The pattern of third molar impaction in a Central Anatolian Turkish population was characterized by a high prevalence rate of level C impaction with vertical position. Pain and pericoronitis were the most common symptoms usually associated with level A impaction and vertical position. © 2015 S. Karger AG, Basel.

Araz S.O.,Klrlkkale University | Calln R.,Klrlkkale University | Pul M.,Klrlkkale University | Bican O.,Klrlkkale University | Okur O.,Klrlkkale University
High Temperature Materials and Processes | Year: 2015

In this study, microstructural, mechanical and wear properties of TiB2 reinforced Al 2014-based composites produced by vacuum infiltration were investigated under different production temperatures. It was observed that the microstructures of the composites consisted of Al matrix and TiB2 particles. TiB2 particles exhibit various shapes such as cubic, triangle and spherical. It was observed that the hardness and porosity of the composites increased with increasing TiB2 content. It was also observed that the production temperature has an important effect on the porosity and hardness of the produced composites. The highest wear resistance was obtained from Al 2014-8% TiB2 composite among the materials tested. It was observed that the production temperature and hardness are effective parameters on wear of produced composites. Evaluation of microstructural and mechanical test results suggest that it would be beneficial to keep the production temperature around 800 °C and Al 2014-8% TiB2 composite can be recommended for engineering applications where the hardness and wear resistance are considered to be significant factors. © 2015 by De Gruyter.

Simsek M.,Klrlkkale University | Polat E.,Klrlkkale University
2016 24th Signal Processing and Communication Application Conference, SIU 2016 - Proceedings | Year: 2016

Due to hardware limitations, hyperspectral imagery has low spatial resolution. It can be obtained super- resolution hyperspectral imagery by means of sparse representation-based methods that are designed for improving spatial resolution. In this paper, the effect of sparse representation-based dictionary learning algorithms including K-SVD, ODL and Bayes on obtaining super-resolution images with low error and high quality has been investigated. The method with best results has been identified. © 2016 IEEE.

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