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Samsun, Turkey

Atli Sekeroglu Z.,Ordu University | Akar A.,Ondokuz Mayys University | Sekeroglu V.,Ordu University
International Journal of Radiation Biology

Purpose: One of the most important issues regarding radiofrequency electromagnetic fields (RF-EMF) is their effect on genetic material. Therefore, we investigated the cytogenotoxic effects of 900 MHz radiofrequency electromagnetic fields (RF-EMF) and the effect of a recovery period after exposure to RF-EMF on bone marrow cells of immature and mature rats. Materials and methods: The immature and mature rats in treatment groups were exposed to RF-EMF for 2 h/day for 45 days. Average electrical field values for immature and mature rats were 28.1 ± 4.8 V/m and 20.0 ± 3.2 V/m, respectively. Whole-body specific absorption rate (SAR) values for immature and mature rats were in the range of 0.38-0.78 W/kg, and 0.31-0.52 W/kg during the 45 days, respectively. Two recovery groups were kept for 15 days after RF-EMF exposure. Results: Significant differences were observed in chromosome aberrations (CA), micronucleus (MN) frequency, mitotic index (MI) and ratio of polychromatic erythrocytes (PCE) in all treatment and recovery groups. The cytogenotoxic damage in immature rats was statistically higher than the mature rats. The recovery period did not reduce the damage to the same extent as the corresponding control groups. Conclusions: The exposure of RF-EMF leads to cytotoxic and genotoxic damage in immature and mature rats. More sensitive studies are required to elucidate the possible carcinogenic risk of EMF exposure in humans, especially children. © 2013 Informa UK, Ltd. Source

Celebi H.,Anadolu University | Gurbuz M.,Anadolu University | Gurbuz M.,Ondokuz Mayys University | Koparal S.,Anadolu University | Dogan A.,Anadolu University
Composite Interfaces

Chitosan/poly(vinyl alcohol) (CS/PVA) nanofibers with a diameter in the range of 60-70 nm were prepared by electrospinning method. The effect of CS/PVA blend ratio and process parameters on the morphology and diameter of nanofibers was investigated by SEM analysis. The FT-IR and differential scanning calorimetry analysis of nanofibers revealed that intermolecular hydrogen bonds were formed between CS and PVA. Weight fractions of polymers in the electrospun nonwoven fibers mats were determined by thermal gravimetric analysis and were close to ratio of polymers in the blend solution. The silver ion (Ag +)-incorporated nanocrystalline hydroxyapatite (HAP) particles, determined as about 70 nm in diameter, were synthesized by wet chemical method. These nanoparticles were added to the CS/PVA blend solution in order to increase antibacterial activity of electrospun fibers. It was observed that the synthesized nanofibers including Ag+-incorporated HAP nanoparticles exhibited antibacterial efficiency against Escherichia coli. The antibacterial electrospun CS/PVA nanofibers are the potential candidate for biomedical applications, because they provide an efficient way to fulfill new requirements for material properties. © 2013 Taylor and Francis. Source

Bayrak Ozbucak T.,Ordu University | Kutbay H.G.,Ondokuz Mayys University | Yalcin S.,Ordu University | Kilic D.D.,Amasya Science and Art Center

Corylus avellana var. avellana (Corylaceae) has a widespread distribution in the Central Black Sea Region of Turkey and is very valuable in the food industry and plays an important role in the economy of the Black Sea Region of Turkey. In this study, nitrogen (N) and phosphorus (P) concentrations along a topographical gradient (from sea level to 550 m) and through the growing season (from April to October) were investigated. In addition to this, foliar resorption was also studied as resorption efficiency (RE) and resorption proficiency (RP) which is defined as the proportion of nutrients withdrawn from leaves and the N and P concentrations in senesced leaves, respectively. Statistically significant differences were not found with respect to leaf N concentration and SLA during the growing season although leaf P concentration, leaf N/P ratio and SLA were significantly changed during the growing season. Except for N RE, P RE, N RP, and P RP all of the leaf traits were significantly changed along the topographic gradient. The N/P ratio which is an indicator of N- and P-limitation decreased during the growing season and along the topographic gradient. The N and P concentrations in the senescent leaves of C. avellana was below 50 μg cm -2 and 3 μg cm -2, respectively along the topographic gradient and this species is N and P-proficient according to the threshold values. Soil properties along the topographic gradient also changed. Source

Adiguzel R.,Tunceli University | Gunduz B.,Muo Alparslan University | Turan N.,University of Science and Arts of Iran | Topcu Y.,Ondokuz Mayys University
Revista de Chimie

We investigated the optical properties and the transmittance characterizations of the stock solutions of the Co (II) and Ni(II) complexes of Saccharin and determined the molar extinction coefficients at different molarity. The molar extinction coefficients (ε) values of the Co (II) and Ni(II) complexes in the first region decrease with increasing molarity, and the epsi; values of the Co (II) and Ni(II) complexes at lower wavelength are higher than that of the values at higher wavelength. The absorption band edge values of the Co (II) complex shift from 3.584 to 3.139 eV with the increasing molarity, while the absorption band edge values of the Ni (II) complex shift from 3.574 to 3.493 eV with the increasing molarity. The plots of refractive index of the Co(II) and Ni(II) complexes consist of two anomalous (abnormal) dispersion regions and one normal dispersion region. The direct energy-gap of the Co(II) complex can be more decreased with molarity. The absorbance, molar extinction coefficients, refractive index values of the Co(II) and Ni(II) complexes decrease, while the average transmittance in the visible region, direct optical band-gap values of the Co (II) and Ni (II) complexes increase with increasing volume of DMF solvent or decreasing volume of the solutions of the Co (II) and Ni(II) complexes. Source

In this study, variation in specific leaf area (SLA) and leaf mass per area (LMA) of evergreen Phillyrea latifolia and decidious Quercus cerris var. cerris were examined according to directional, seasonal and climatical parameters during a vegetation period. Calculations were done in both area and mass basis to determine if there was a difference in results or not. The field study was carried out in Q. cerris forest in Samsun, northern Turkey. Leaves were collected monthly from individuals chosen in different directions. SLA and LMA of both taxon were calculated and evaluated statistically. As a result, except June in P. latifolia, there wasn't significant difference in SLA and LMA due to direction. However, There were seasonal variations in SLA and LMA for both taxon. Maximum SLA was estimated in spring, May, maximum LMA was estimated in fall, September in both taxon. SLA and LMA of Q. cerris var. cerris were related with temperature, not related with fall and relative moisture, of P. latifolia weren't related with temperature, fall and relative moisture. Compairing results calculated in area and mass basis, there wasn't any differences in Q. cerris var. cerris; in P. latifolia number of variation groups increased in mass basis. Correlation between SLA and dry mass, LMA and dry mass were examined; it was found that correlation between LMA and biomass was most linear in both taxon. Thus, it is thought that evaluation in mass basis is more suitable for variation studies related with ecological factors. Source

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