48 research outputs found
Pricing pension buy-outs under stochastic interest and mortality rates
Pension buy-out is a special financial asset issued to offload the pension liabilities holistically in exchange for an upfront premium. In this paper, we concentrate on the pricing of pension buy-outs under dependence between interest and mortality rates risks with an explicit correlation structure in a continuous time framework. Change of measure technique is invoked to simplify the valuation. We also present how to obtain the buy-out price for a hypothetical benefit pension scheme using stochastic models to govern the dynamics of interest and mortality rates. Besides employing a non-mean reverting specification of the Ornstein–Uhlenbeck process and a continuous version of Lee–Carter setting for modeling mortality rates, we prefer Vasicek and Cox–Ingersoll–Ross models for short rates. We provide numerical results under various scenarios along with the confidence intervals using Monte Carlo simulations
Effectiveness of sugammadex for cerebral ischemia/reperfusion injury
AbstractCerebral ischemia may cause permanent brain damage and behavioral dysfunction. The efficacy and mechanisms of pharmacological treatments administered immediately after cerebral damage are not fully known. Sugammadex is a licensed medication. As other cyclodextrins have not passed the necessary phase tests, trade preparations are not available, whereas sugammadex is frequently used in clinical anesthetic practice. Previous studies have not clearly described the effects of the cyclodextrin family on cerebral ischemia/reperfusion (I/R) damage. The aim of this study was to determine whether sugammadex had a neuroprotective effect against transient global cerebral ischemia. Animals were assigned to control, sham-operated, S 16 and S 100 groups. Transient global cerebral ischemia was induced by 10-minute occlusion of the bilateral common carotid artery, followed by 24-hour reperfusion. At the end of the experiment, neurological behavior scoring was performed on the rats, followed by evaluation of histomorphological and biochemical measurements. Sugammadex 16 mg/kg and 100 mg/kg improved neurological outcome, which was associated with reductions in both histological and neurological scores. The hippocampus TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) and caspase results in the S 16 and S 100 treatment groups were significantly lower than those of the I/R group. Neurological scores in the treated groups were significantly higher than those of the I/R group. The study showed that treatment with 16 mg/kg and 100 mg/kg sugammadex had a neuroprotective effect in a transient global cerebral I/R rat model. However, 100 mg/kg sugammadex was more neuroprotective in rats
Renal Ischemia/Reperfusion Injury in Diabetic Rats: The Role of Local Ischemic Preconditioning
Background. The aim of this study was to evaluate the effects of local ischemic preconditioning using biochemical markers and histopathologically in the diabetic rat renal IR injury model. Methods. DM was induced using streptozotocin. Rats were divided into four groups: Group I, nondiabetic sham group (n=7), Group II, diabetic sham group (n=6), Group III, diabetic IR group (diabetic IR group, n=6), and Group IV, diabetic IR + local ischemic preconditioning group (diabetic IR + LIPC group, n=6). Ischemic renal injury was induced by clamping the bilateral renal artery for 45 min. 4 h following ischemia, clearance protocols were applied to assess biochemical markers and histopathologically in rat kidneys. Results. The histomorphologic total cell injury scores of the nondiabetic sham group were significantly lower than diabetic sham, diabetic IR, and diabetic IR + LIPC groups. Diabetic IR group scores were not significantly different than the diabetic sham group. But diabetic IR + LIPC group scores were significantly higher than the diabetic sham and diabetic IR groups. Conclusion. Local ischemic preconditioning does not reduce the risk of renal injury induced by ischemia/reperfusion in diabetic rat model
Electronic and phonon properties of Sc-TM (TM = Ag, Cu, Pd, Rh, Ru) compounds
WOS: 000274222000007A theoretical study of structural, electronic and phonon properties of the Sc-TM (TM = Ag, Cu, Pd, Rh, Ru) in the B2 phase was presented using the density functional theory within the generalized gradient approximation (GGA). The ground state quantities such as lattice parameter, bulk modulus and first-order pressure derivative of the bulk modulus, were evaluated. The calculated structural and electronic properties were in good agreement with previous theoretical and experimental results. The calculated total density of states showed that they were all metallic. Phonon-dispersion curves were obtained using the first principles linear-response approach of the density functional perturbation theory (DFPT). (C) 2009 Elsevier B.V. All rights reserved.Gazi UniversityGazi University [05/2009-39]This work was supported by the Gazi University Research Project Unit under Project No. 05/2009-39
Calculations of Structural, Elastic, Electronic, Magnetic and Phonon Properties of FeNiMnAl by the First Principles
International Conference of Computational Methods in Sciences and Engineering 2014 (ICCMSE) -- APR 04-07, 2014 -- Athens, GREECEWOS: 000346015200045The electronic, elastic and dynamical properties of the quaternary alloy FeNiMnAl have been investigated using a pseudopotential plane wave method within the generalized gradient approximation (GGA). We determined the lattice parameters and the bulk modulus B. In addition, the elastic properties such as elastic constans (C-11, C-12 and C-44), the shear modulus G, the young modulus E, the poisson's ratio sigma and the B/G ratio are also given. The FeNiMnAl Heusler alloy exhibit a ferromagnetic half-metallic behavior with the total magnetic moment of 4.02 mu(B). The phonon dispersion of FeNiMnAl has been performed using the density functional theory and the direct method with 2x2x2 supercell.European Soc Computat Methods Sci Engn & Techno
Structural, elastic, electronic, magnetic and vibrational properties of CuCoMnGa under pressure
International Conference of Computational Methods in Sciences and Engineering 2014 (ICCMSE) -- APR 04-07, 2014 -- Athens, GREECEWOS: 000346015200047First principles calculations for the structural, electronic, elastic and phonon properties of the cubic quaternary heusler alloy CuCoMnGa on pressure have been reported by density functional theory (DFT) within generalized gradient approximation (GGA). The calculated values of the elastic constants were used for estimations of the Debye temperatures, the bulk modulus, the shear modulus, the young modulus E, the poisson's ratio sigma and the B/G ratio. The elastic constants satisfy all of the mechanical stability criteria. The electronic structures of the ferromagnetic configuration for CuCoMnGa have a metallic character. The estimated magnetic moment per formula unit is 3.76 mu(B). The phonon dispersion is studied using the supercell approach, and the stable nature at 0.2 GPa pressure is observed.European Soc Computat Methods Sci Engn & Techno
Phonon and elastic properties of AlSc and MgSc from first-principles calculations
WOS: 000279295300022First principle calculations of structural, electronic, elastic, and phonon properties of the intermetallic compounds like MgSc and AlSc in the B2 (CsCl) structure are presented in this study, using the pseudo-potential plane waves approach based on the density functional theory, within the generalized gradient approximation. The calculated lattice constants, bulk modulus, and first-order pressure derivative of the bulk modulus are reported for the B2 structure and compared with the earlier experimental and theoretical calculations. The numerical first principles calculation of the elastic constants were used to calculate C(11), C(12) and C(44) for these compounds. The present results concur with the earlier theoretical calculations. Electronic band structures and densities of states have been derived for MgSc and AlSc and subsequently, a linear-response approach to the density functional theory is used to derive the phonon frequencies and densities of states. (C) 2010 Elsevier B.V. All rights reserved.Yuzuncu Yil UniversityYuzuncu Yil University [2008-FED-B090]; Gazi UniversityGazi University [05/2009-39]This work was supported by the Yuzuncu Yil University Research Project Unit under Project No. 2008-FED-B090 and the Gazi University Research Project Unit under Project No. 05/2009-39. The computations were partly performed at the TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). We gratefully acknowledge Dr. Huseyin Murat Tutuncu for his valuable on the final form this manuscript
Congenital Bronchial Artery-Pulmonary Artery Fistula in a Young Adult
Primary vascular malformations such as connection between bronchial artery and pulmonary artery or pulmonary vein are quite rare. A 18-year-old male patient with the first episode of massive hemoptysis was found to have bronchial artery-pulmonary artery fistula, a rare vascular anomaly, on selective bronchial angiography. Since medical history revealed no acquired cause, it is considered congenital. He underwent bronchial artery embolization and hemoptysis was completely resolved after endovascular treatment. The presence of such vascular anomalies should be suspected in patients with massive hemoptysis. Bronchial artery embolization is a safe and effective nonsurgical treatment option for such patients. [Cukurova Med J 2015; 40(4.000): 830-835
Comparison of the protective effects of various antiulcer agents alone or in combination on indomethacin-induced gastric ulcers in rats
The aim of this study which was structured with the objective of determination of the optimum protective therapy against the long term NSAID therapy-induced ulcers was to compare the gastro-protective effects of various antiulcer drugs (ranitidine, omeprazole, bismuth and misoprostol)alone or in combination with each other in different doses on indomethacin-induced gastric ulcers in rats