Surface anisotropy change of CoFe2O4 nanoparticles depending on thickness of coated SiO2 shell

We systematically investigated the effective surface anisotropy of CoFe2O4 nanoparticles dependant on the thickness of SiO2 shell. XRD (X-ray powder diffraction) patterns and TEM (transmission electron microscopy) micrographs were used to investigate the structure of particles and thickness of SiO2 shell, respectively. The thicknesses of SiO2 shell with 5.41 nm on CoFe2O4 nanoparticles were increased up to 14.04 +/- 0.05 nm by changing the amount of added TEOS by, 0.10, 0.25, 0.50, 1.00, 1.50, and 2.50 mL. The increase of the SiO2 thickness shell decreased the effective anisotropy due to decline the effectiveness of the dipolar magnetostatic interactions, determined from Vogel-Fulcher equation, between the particles. The declines in the Keff values stabled at around 3.76 +/- 0.11 x 10(5) J/m(3) for TEOS amount higher than 1.5 mL

Carotid intima-media thickness in chronic obstructive pulmonary disease and survival: A multicenter prospective study

Introduction Chronic obstructive pulmonary disease (COPD) is associated with increased cardiovascular morbidity and mortality. Carotid intima-media thickness (CIMT) is a noninvasive method assessing atherosclerosis. Objective It was aimed to determine relationship and survival between COPD and CIMT. Methods CIMT was measured using Doppler ultrasound (USG) in 668 stable COPD patients at 24 centers. Patients were followed-up for 2 years. Results There were 610 patients who completed the study. There were 200 patients CIMT with = 0.78 mm (group 2). There was a significant difference at the parameters of age, gender, smoking load, biomass exposure, GOLD groups and degree of airway obstruction (FEV1) between groups 1 and 2. Our results revealed positive correlations between mean CIMT and age, smoking load (pack-years), biomass exposure (years), exacerbation rate (last year), duration of hypertension (years) and cholesterol level; negative correlations between CIMT and FEV1 (P 0.05). Conclusion This study is the first regarding CIMT with combined GOLD assessment groups. It has revealed important findings supporting the increase in atherosclerosis risk in COPD patients. We recommend Doppler USG of the carotid artery in COPD patients at severe stages