Abbas O.L.,Ahi Evran University
Journal of Burn Care and Research | Year: 2017
The Notch pathway ligand Delta-like 4 (Dll4) functions as an antiangiogenic factor, inhibiting vascular endothelial growth factor (VEGF)–induced angiogenesis. This function is documented in tumor and embryonic vasculature. However, its implication in burn wounds remains unexplored. Our objective was to explore the involvement of the Notch in the healing of zone of stasis burns. We hypothesized that anti-Dll4 therapy would prevent progressive necrosis in the stasis zone by promoting angiogenesis. Burns were created in 21 rats using the comb burn model. The Notch inhibitor N-[N-(3,5-difluorophenacetyl)-1-alanyl]-S-phenylglycine-t-butyl-ester was administered in the treatment group. Controls were given the same amount of solvent. Seven days after the burn, skin samples were evaluated for VEGF and Dll4 gene expressions. Immunohistochemical analysis was used for the assessment of vascular density, endothelial Dll4 expression, and apoptosis count. Histologic grading of tissue damage was performed. Circulating levels of VEGF and Dll4 were determined. VEGF and Dll4 mRNA levels were found to be simultaneously induced after the burn. In the treatment group, a significant increase in the number of vessels was observed. However, gross evaluation documented an expansion of necrosis to the zone of stasis with marked activation of apoptosis. Histologic assessment showed that the resultant vascular overgrowth was accompanied by extensive edema and abundant infiltration of leukocytes. We provide evidence for the involvement of Notch in the regulation of angiogenesis in zone of stasis burns. © 2017 The American Burn Association
Arikan N.,Ahi Evran University
AIP Conference Proceedings | Year: 2017
A theoretical study is presented for the structural, electronic, elastic and phonon properties of Co3W compounds in L12 phase in the framework of density functional theory. The calculations are carried out within the PBE-GGA for the exchange correlation potential. The electronic structure and particle density of states (DOS) show that Co3W compound is metallic with sturdy hybridization near the Fermi level. The phonon dispersion curves, and the projected density of states been investigated for the first time with an ab initio method using density functional perturbation theory (DFPT). Temperature variations of specific heat capacity in the range of 0-2000 K are obtained using the quasi-harmonic model. © 2017 Author(s).
Gur H.,Ahi Evran University
Biological Journal of the Linnean Society | Year: 2013
The present study aimed to understand how Anatolian ground squirrels, Spermophilus xanthoprymnus (Bennett, 1835), have responded to global climate changes through the Late Quaternary glacial-interglacial cycles. Accordingly, ecological niche modelling was used, together with molecular phylogeography. Using species occurrence data compiled from field observations and relevant sources and the maximum entropy machine learning algorithm in MAXENT, an ecological niche model was developed to predict the potential geographical distribution of S. xanthoprymnus under reconstructed past (the Last Interglacial, approximately 130000-116000years ago and the Last Glacial Maximum, 21000years ago) and present (1950-2000) bioclimatic conditions. In addition, using cytochrome b mitochondrial DNA sequences deposited in GenBank and the Bayesian skyline plot in BEAST, demographic events (population fluctuations) were further assessed over the history of Anatolian ground squirrels. Combined ecological niche modelling and molecular phylogeography revealed that S. xanthoprymnus, itself also a temperate (mid-latitude) species, has responded to global climate changes through the Late Quaternary glacial-interglacial cycles in a fashion converse to that of most temperate (mid-latitude) species: its range expanded rather than contracted during the glacial periods and contracted rather than expanded during the interglacial periods. In other words, Anatolian ground squirrels have been in refugia during the interglacial periods, suggesting that the classical paradigm of glacial range contraction and interglacial range expansion for temperate species may not be as general as previously assumed. © 2013 The Linnean Society of London.
Ciftci H.,Ahi Evran University
Desalination | Year: 2010
A solid phase extraction method was developed for the determination, preconcentration and separation of cadmium. The method is based on the adsorption of cadmium as 4-(2-pyridylazo) resorcinol (PAR) complex on Duolite XAD-761 resin. The extracted cadmium was determined by Flame Atomic Absorption Spectrometry (FAAS). The optimum experimental conditions for the cadmium assay were investigated. The optimum pH value for quantitative sorption of Cd-PAR was found between 3.5 and 5.5. Elution process was performed by using 5 mL of ethanol-2 mol L-1 HNO3 mixtures (1:3 v/v). The preconcentration factor was found as 160 for 800 mL aqueous solution containing 2.5 μg Cd. In optimized conditions, the detection limit for cadmium was found to be 0.38 μg L-1. The method was applied to the determination of cadmium in different water samples. © 2010.
Erdogdu Y.,Ahi Evran University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013
In this work, we report a combined experimental and theoretical study on molecular structure, vibrational spectra and electronic properties of Esculetin (ESC). The FT-IR, FT-Raman and FT-NMR spectra have been recorded and analyzed. The molecular geometry, harmonic vibrational frequencies, chemical shifts, HOMO, LUMO energies and molecular electrostatic potential map of ESC have been calculated by using Density Functional Theory (B3LYP) with 6-311G++(d,p), cc-pVDZ, cc-pVQZ and cc-pVTZ basis sets. © 2013 Elsevier B.V. All rights reserved.
Ciftci H.,Ahi Evran University
Current Analytical Chemistry | Year: 2010
A new solid-phase extraction method was developed for trace analysis of cobalt on Duolite XAD-761 resin by using flame atomic absorption spectrometry (FAAS). The optimum experimental conditions for the quantitative sorption of Co(II)-PAR (cobalt chelates with 4-(2-Pyridylazo) resorcinol), pH, effect of sample flow rate, concentration of eluent, sorption capacity of resin and the effect of diverse ions on the preconcentration of analytes have been investigated. The optimum pH values for quantitative sorption of Co (II)-PAR were between 5 and 7.5. Eluted process was performed by 4 mL ethanol. The sorption capacity of resin was determined to be 8.6 mg g-1 for cobalt with a preconcentration factor of 150. In optimized conditions, the detection limit for cobalt ions was found to be 0.36 μg L-1. The accuracy of the proposed procedure was checked by using NIST 1573 a tomato leave as a standard reference material. The achieved results were in good agreement with certified values. The proposed method was applied for the determination of cobalt in different water samples, such as city line, geothermal, river and lake. © 2010 Bentham Science Publishers Ltd.
Gur H.,Ahi Evran University
Biological Journal of the Linnean Society | Year: 2010
A phylogenetic comparative analysis of geographic variation in body size of an obligately hibernating marmotine species (Anatolian ground squirrels, Spermophilus xanthoprymnus) is presented in relation to environmental variables that pertain to four principal hypotheses (heat conservation, heat dissipation, primary productivity, and seasonality hypotheses). Adult Anatolian ground squirrels (78 males and 90 females) were collected from ten geographic localities in Anatolia for use in morphometric analyses. First, the study tested whether significant variation in body size occurs over the geographic range of S. xanthoprymnus. Then, to understand the possible cause(s) of the observed pattern of geographic variation in body size of Anatolian ground squirrels, four hypotheses were tested, separately and simultaneously, using a phylogenetic comparative method. Overall, food availability (primary productivity hypothesis) and, especially in males, over-winter fasting endurance (seasonality hypothesis) are likely the primary underlying mechanisms generating the observed pattern of increasing body size towards colder, more seasonal environments, with higher summer precipitation and productivity (or a Bergmannian size pattern). © 2010 The Linnean Society of London.
Arkan N.,Ahi Evran University
Journal of Physics and Chemistry of Solids | Year: 2013
The elastic, electronic, and phonon properties of the intermetallic compounds Zr3Al and Sc3Al in the L12 structure have been investigated in detail by employing an ab initio pseudopotential method and a linear-response technique within a generalized gradient approximation (GGA) of the density-functional theory (DFT) scheme. The calculated ground-state properties such as lattice constants and bulk modulus agree well with the previous theoretical calculations. The numerical first-principles calculations of the elastic constants have been used to calculate C11, C12, and C44 for Zr 3Al and Sc3Al. The electronic band structures of Zr 3Al and Sc3Al show that at the Fermi level, a major part of the contribution comes from Zr 4d (Sc 3d) states. The phonon-dispersion curves and phonon total and partial density of states based on the linear-response method have been investigated for both materials. Temperature variations of specific heat capacity in the range of 0-500 K are obtained using the quasi-harmonic model. © 2013 Elsevier Ltd.
Ciftci H.,Ahi Evran University
Clean - Soil, Air, Water | Year: 2010
In this study, a new solid-phase extraction procedure has been developed for precon-centration and determination of Co ions in different water samples by flame atomic absorption spectrometry (FAAS). Cobalt was preconcentrated as N,N'-bis(pyridine-2-yl-methyl)benzene-1,4-diamine (Co-BPMBDA) from sample solutions using a column containing Amberlite XAD-7 and was determined. In order to achieve the best performance for the method, effects of several parameters such as pH, concentrations of ligand, sample flow rate, eluent, and matrix ions on the method efficiency were investigated. Under optimum conditions, the preconcentration factor was found to be 200 for 1000 mL waters samples. Detection limit based on the 3Sb criterion was calculated as 0.24 μg/L for 100 mL of sample solution and relative standard deviation was found to be 1.8%. The method was applied to determine the trace amounts of cobalt in water samples. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Demir T.,Ahi Evran University |
Buyukguclu T.,Public Healthcare Center
International Journal of Infectious Diseases | Year: 2013
Objectives: The aim of this study was to evaluate the in vitro activities of antimicrobial agents including fosfomycin tromethamine against Gram-negative isolates recovered from urine samples. Methods: A total of 2334 strains (1562 Escherichia coli, 509 Klebsiella spp, 85 Proteus spp, 75 Pseudomonas spp, 45 Enterobacter spp, 37 Acinetobacter baumannii, 8 Citrobacter spp, 7 Morganella morganii, and 6 Serratia spp) were identified by VITEK 2 during the study period, November 2008 to June 2012. Antimicrobial susceptibilities of the strains were also evaluated using the Kirby-Bauer disk diffusion method, in accordance with the Clinical and Laboratory Standards Institute guidelines. Results: Overall, 2160 (92.5%) of the isolates tested were susceptible to fosfomycin tromethamine. Higher resistance rates were observed among inpatients compared to outpatients. Resistance rates by strain were: 2.0% for E. coli, 4.4% for Enterobacter spp, 6.9% for Klebsiella spp, 9.4% for Proteus spp, 48.6% for A. baumannii, 56.0% for Pseudomonas spp, and 100% for Morganella morganii. All Serratia spp and Citrobacter spp strains were susceptible. Extended-spectrum beta-lactamase (ESBL)-producing isolates displayed higher fosfomycin resistance rates than negative strains (19.2% vs. 2.9%). The highest in vitro activity was detected for amikacin, piperacillin-tazobactam, and imipenem for all strains including ESBL-producers. Conclusions: Regardless of ESBL production, the excellent activity of fosfomycin against E. coli, Enterobacter spp, Serratia spp, and Citrobacter spp, indicates that the drug is a valuable therapeutic option for urinary tract infections, even those with co-trimoxazole- and ciprofloxacin-resistant isolates, but not in ESBL-producing Klebsiella spp, Pseudomonas spp, A. baumannii, and Proteus spp. Further studies should be carried out to determine the in vivo drug activity among Enterobacteriaceae other than E. coli. © 2013 International Society for Infectious Diseases.