Ahi Evran University

About: Ahi Evran University is a education organization based out in Kırşehir, Turkey. It is known for research contribution in the topics: Density functional theory & Ab initio. The organization has 842 authors who have published 2270 publications receiving 21904 citations.

Persistent left superior vena cava draining to the left atrium: A case report and review of the literature.

Abstract: Background Persistent left superior vena cava is a rare but important congenital vascular anomaly. However, PLSVC with absent RSVC (isolated PLSVC) is a very rare venous malformation We report on a rare case of persistent left superior vena cava (PLSVC) with absent right superior vena cava (RSVC). Case report This venous malformation was identified incidentally in a 69-year-old woman during chest multi-detector computed tomography (MDCT). On chest MDCT, the SVC was noted on the left side. A bridging vein drained the right jugular and right subclavian veins and joined the left brachiocephalic vein in order to form the PLSVC, which descended on the left side of the mediastinum and drained into the left atrium (LA). The patient had no additional cardiac anomaly. Conclusions Isolated PLSVC is usually asymptomatic but it can pose difficulties for establishing central venous access, pacemaker implantation and cardiothoracic surgery. This condition is also associated with an increased incidence of congenital heart disease, arrhythmias and conduction disturbances. A wide spectrum of clinicians should be aware of this anomaly, its variations and possible complications.

Evaluation of Serum Superoxide Dismutase Activity, Malondialdehyde, and Zinc and Copper Levels in Patients With Keratoconus.

Abstract: Purpose: The aim of this study was to evaluate the relationship between antioxidant superoxide dismutase (SOD) enzyme activity, malondialdehyde (MDA) as a lipid peroxidation marker, and some trace elements such as zinc (Zn) and copper (Cu) levels in patients with keratoconus. Methods: A total of 58 patients with keratoconus and 53 control subjects with similar age and sex were evaluated in this study. The modified Krumeich keratoconus classification was used to divide the patients into 4 stages. Serum SOD activity, MDA, and zinc and copper levels were compared between the patient and control groups. Results: The median serum SOD activity, MDA, and Zn and Cu levels were 27.2 (42.4–13.7) U/mL, 10.2 (11.9–8.5) nmol/mL, 87.9 (104.6–76.5) μmol/L, and 103.2 (117.9–90.3) μmol/L in the keratoconus group and 26.2 (32.5–14.4) U/mL, 8.8 (11.4–7.1) nmol/mL, 100.5 (121.1–81.8) μmol/L, and 98.4 (120.3–83.4) μmol/L in the control group, respectively. There was a statistically significant difference between the MDA and Zn levels of the keratoconus group and control subjects but not between the respective SOD activities or Cu levels (P = 0.016, P = 0.031, P = 0.440, and P = 0.376, respectively). We found no significant difference between the keratoconus group stages for serum SOD activity, serum MDA, and Zn and Cu levels (P > 0.05), and there was also no significant correlation between the keratoconus group stages and serum SOD activity, serum MDA, and Zn and Cu levels (P > 0.05). Conclusions: There is imbalance in the systemic oxidant/antioxidant status where Zn deficiency also plays a role in patients with keratoconus.

The Impact of Economic Growth and Foreign Direct Investment on CO2 Emissions: The Case of Turkey

Abstract: . The aim of this study is to evaluate the relationship between carbon dioxide emissions, economic growth, foreign direct investment and energy consumption in Turkey. To this extent, ARDL bounds testing method to cointegration is being implemented over the period of 1970-2014. The long run estimation results suggest that economic growth and energy consumption have positive impacts on CO 2 emissions. However, this research did not find anysignificant relationship between foreign direct investment and CO 2 emissions. As a result of these findings, this research reveals some important policy recommendations. Keywords. Carbon dioxide emissions, Foreign direct investment, Economic growth, Energy consumption, ARDL. JEL. F20, O10, Q40, Q50.

Cytotoxicity of Piper aduncum (Piperaceae) essential oil in brown stink bug Euschistus heros (Heteroptera: Pentatomidae).

Abstract: Euschistus heros (F.) (Hemiptera: Pentatomidae) is a soybean pest in Brazil, controlled with synthetic chemical insecticides, which may be harmful to the environment and humans, as well as to select pest resistant strains. The research for new pest control strategies such as the use of plant essential oils has been increased due to the selectivity and biodegradation of these molecules. The objective was to evaluate the cytological changes in the salivary glands, fat body and midgut of E. heros exposed to different concentrations of essential oil of Piper aduncum L. (Piperales: Piperaceae), which the main compounds were identified as myristicin 30.03%, aromadendrene 9.20%, dillapiole 8.43%, α-serinene 7.31%, tridecane 6.26%, γ-elemene 4.58% and o-cymene 4.20%. The essential oil of P. aduncum was toxic for E. heros with LD50 = 36.23 mg per insect and LD90 = 50.42 mg per insect. Cytological changes such as tissue disruption, increase in mitochondria population, and glycogen and lipid depletion occur in the fat body cells, whereas salivary glands and midgut are not affected by this essential oil. Results suggest that P. aduncum essential oil causes fat body cellular stress, which may compromise some physiological processes for the insect survival.

The distribution of the barrier height in Al–TiW–Pd2Si/n-Si Schottky diodes from I–V–T measurements

Abstract: The forward and reverse bias current–voltage (I–V) characteristics of Al–TiW–Pd2Si/n-Si Schottky barrier diodes (SBDs) were measured in the temperature range of 300–400 K. The estimated zero-bias barrier height ΦB0 and the ideality factor n assuming thermionic emission (TE) theory show a strong temperature dependence. While n decreases, ΦB0 increases with increasing temperature. The Richardson plot is found to be linear in the temperature range measured, but the activation energy value of 0.378 eV and the Richardson constant (A*) value of 15.51 A cm−2 K−2 obtained in this plot are much lower than the known values. Such behavior is attributed to Schottky barrier inhomogeneities by assuming a Gaussian distribution of barrier heights (BHs) due to BH inhomogeneities that prevail at the interface. Also, the ΦB0 versus q/2kT plot was drawn to obtain evidence of a Gaussian distribution of the BHs, and ΦB0 = 0.535 eV and σ0 = 0.069 V for the mean BH and zero-bias standard deviation, respectively, have been obtained from this plot. Thus, the modified ln(I0/T2) − q2σ20/2k2T2 versus q/kT plot gives ΦB0 and A* as 0.510 eV and 121.96 A cm−2 K−2, respectively. This value of the Richardson constant 121.96 A cm−2 K−2 is very close to the theoretical value of 120 A K−2 cm−2 for n-type Si. Hence, it has been concluded that the temperature dependence of the forward I–V characteristics of the Al–TiW–Pd2Si/n-Si Schottky barrier diodes can be successfully explained on the basis of a thermionic emission mechanism with a Gaussian distribution of the BHs.