Trakya University

About: Trakya University is a education organization based out in Edirne, Turkey. It is known for research contribution in the topics: Population & Medicine. The organization has 2727 authors who have published 5490 publications receiving 76048 citations. The organization is also known as: University of Thrace & Trakya Üniversitesi.

Noncoaxial vibration and buckling analysis of embedded double-walled carbon nanotubes by using doublet mechanics

Abstract: Free vibration and buckling of double-walled carbon nanotubes embedded in an elastic medium with simply supported boundary conditions are studied. Doublet Mechanics (DM) is used in the analysis. Macro level strains and stresses are defined in terms of micro level strains and stresses in the DM theory. These micro deformations and micro stresses are expanded in Taylor series and the number of terms in the Taylor series defines degree of the approach. Double-walled carbon nanotubes are modelled as Euler-Bernoulli beams embedded in an elastic medium. Critical buckling loads and free vibration frequencies are obtained by using DM and compared with the classical elasticity solutions. It is obtained that for some frequencies carbon nanotubes move noncoaxially. Noncoaxial vibration and buckling affect the physical properties of carbon nanotubes. The present results show that a length scale dependent DM can be used in the design of nano electro-mechanical systems.

Comparison of QoS-aware single-path vs. multi-path routing protocols for image transmission in wireless multimedia sensor networks

Abstract: Wireless multimedia sensor network (WMSN) applications require strong multimedia communication competence. Therefore, in WMSN applications, it is necessary to use specific mechanisms in order to handle multimedia communication challenges and address desired energy efficiency and reliability goals. Nevertheless, the existing communication protocols are not suitable for the communication challenges and the desired goals. In this respect, specific mechanisms for prioritization, link-quality estimation and multi-path selection can be employed by quality of service (QoS)-aware routing protocols to meet the reliability and delay requirements of WMSN applications. In this study a novel approach is proposed to set different reliability values for image packets for image transmission in WMSNs. Using this prioritization, important parts of an image are assigned high priority and take priority during data transmission. In order to evaluate the proposed approach, the performance of single-path and multi-path QoS-aware routing protocols has been investigated for WMSN-based image transmission applications. Specifically, comparative performance analysis of single-path routing and multi-path routing in image transmission have been conducted in terms of peak signal-to-noise ratio (PSNR), average delay, reachability, and control overhead. As proven by the results of the performance evaluations in this study, multi-path routing is better than single-path routing in terms of reliability. On the other hand, at high traffic loads, multi-path routing may perform worse in terms of delay due to its associated overhead.

Airborne Alternaria and Cladosporium species and relationship with meteorological conditions in Eskisehir City, Turkey

Abstract: Alternaria and Cladosporium, known as the most allergenic spores were first collected by means of Durham gravimetric sampler from Eskisehir atmosphere from January 1, 2000 to December 31, 2001. The daily, monthly and annual variations in spores/cm2 of Cladosporium and Alternaria were recorded. During this period, a total of 10.231 spores belonging to Cladosporium and Alternaria genera were recorded. Of these spores, 5,103 were identified in 2000 and 5,128 in 2001. While 63.09% of the total spores were those of Cladosporium, 36.91% were of Alternaria. Relationships between airborne fungal spore presence and meteorological conditions were statistically investigated. A Shapiro-Wilk test revealed that the airborne Cladosporium and Alternaria spores differed from a normal distribution. Thus, a Friedmann test was performed followed by a Pearson Correlation Analysis. The effects of rainfall, temperature and wind speed on Cladosporium and Alternaria numbers were non-significant according to the sites and months (p > 0.05), but the effects of relative humidity on Cladosporium and Alternaria numbers were significant (p < 0.01). Spore concentrations reached to their highest levels in May 2001.

Protective effects of vitamin C, alone or in combination with vitamin A, on endotoxin-induced oxidative renal tissue damage in rats.

Abstract: This study was designed to investigate the protective effects of vitamin C and vitamin A on oxidative renal tissue damage. Male Wistar rats were given an intraperitoneal injection of 0.5 ml saline (control) or 0.5 ml solution of lipopolysaccharide (10 mg/kg), which caused endotoxemia. Immediately (within 5 min) after the endotoxin injection, the endotoxemic rats were untreated or treated with intraperitoneal injection of vitamin A (195 mg/kg bw), vitamin C (500 mg/kg bw) or their combination. After 24 hours, tissue and blood samples were obtained for histopathological and biochemical investigation. Endotoxin injection caused renal tissue damage and increased erythrocyte and tissue malondialdehyde (MDA) and serum nitric oxide (NO), urea and creatinine concentrations, but decreased the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities compared to the parameters of control animals. Treatment with vitamin C or with vitamins C and A significantly decreased the MDA levels and serum NO, urea and creatinine levels, recovered the antioxidant enzyme activities (SOD, GSH-Px and CAT), and prevented the renal tissue damage in endotoxemic rats. In contrast, vitamin A alone did not change the altered parameters except for creatinine levels. Notably, the better effects were observed when vitamins A and C given together. It is concluded that vitamin C treatment, alone or its combination with vitamin A, may be beneficial in preventing endotoxin-induced oxidative renal tissue damage and shows potential for clinical use.