Increased asymmetric dimethylarginine and nitric oxide levels in patients with migraine

Asymmetric dimethylarginine (ADMA) has been found as correlated with endothelial dysfunction and oxidative stress. There are few studies regarding ADMA and nitric oxide (NO) levels in patients with migraine and alterations of ADMA and NO levels during migraine attack are not well-known. Therefore, in present study, we aimed to measure NO and ADMA levels in patients with migraine and compare them with the control group to investigate the correlation between migraine, oxidative stress and endothelial dysfunction. The migraine group consisted of 59 patients, including 22 suffering from migraine with aura and 37 suffering from migraine without aura. The control group consisted of 31 healthy volunteers without headache. The patients in migraine group were divided into subgroups based on whether attack period was present or not and whether it was migraine with or without aura. Plasma ADMA levels were measured using an enzyme-linked immunosorbent assay method. Migraine patients had higher concentrations of NO (35.6 ± 7.7, 31.0 ± 6.2 μmol/L, respectively, p = 0.005) and ADMA (0.409 ± 0.028, 0.381 ± 0.044 μmol/L, respectively, p = 0.001) levels when compared with the healthy controls. During migraine attack, NO and ADMA levels were found to be significantly higher in migraine group as compared to control group (respectively, p = 0.015, p = 0.014). Similarly, NO and ADMA levels in the patients with migraine in the interictal period were found to be significantly higher as compared to control group (p = 0.011, p = 0.003). In conclusion, higher ADMA and NO levels of patients with migraine supported that oxidative stress and endothelial dysfunction may have a role in migraine pathogenesis

Обучение академическому письму: проблемы и решения

Обозначены основные проблемы, с которыми сталкиваются преподаватели и студенты при внедрении курса "Академическое письмо". Проведен анализ письменных работ студентов на английском языке, описаны трудности, которые испытывают студенты при их написани

ES&T Guest Comment: Celebrating Bidleman’s 1988 “Atmospheric Processes”

Since its 1988 appearance in ES&T, Terry F. Bidleman’s article, “Atmospheric processes: wet and dry deposition of organic compounds are controlled by their vapor-particle partitioning”, has had a notable impact on the field of contaminant science. The paper has been cited in over 600 journal articles published by authors from every continent. Far from fading into obscurity, the paper’s influence has been remarkably consistent. Citations over the last year match the annual average attained since publication

Determination of mass transfer rates and deposition levels of polycyclic aromatic hydrocarbons (PAHs) using a modified water surface sampler

AbstractThere are different approaches to determine dry deposition velocities (Vd) and mass transfer coefficients (KG) of individual polycyclic aromatic hydrocarbons (PAHs). A modified water surface sampler (MWSS) and a high volume air sampler were concurrently used to determine Vd and KG in this study. Ambient air and deposition samples were collected from August 2004 to May 2005 in Bursa, Turkey. The mean particle-phase dry deposition flux of PAHs was 890±520 ng/m2 d, while the mean gas-phase PAH flux was 5 060±4 260 ng/m2 d. The ratio between fluxes and air concentration values was used in calculation of Vd and KG. The average calculated Vd and KG values for PAH compounds were 0.52±0.36cm/s and 0.69±0.41cm/s, respectively. Despite the fluctuation on seasonal atmospheric concentrations due to regional sources and meteorological conditions, there was no significant difference on deposition velocities and mass transfer rates. KG was also calculated using some models reported in the literature and models developed using the MWSS. The predicted KG determined by models developed using the MWSS was 0.59±0.02cm/s showing a close agreement with the experimentally measured values

PCB mass transfer coefficients determined by application of a water surface sampler

A water surface sampler (WSS) was employed in combination with greased surface deposition plates (GSDPs) to measure the particulate dry deposition and gas exchange of polychlorinated biphenyls (PCBs) in Chicago, IL. Vapor phase PCB fluxes were calculated by subtracting the particulate fluxes obtained from GSDPs from total (particulate + gas) fluxes obtained from the WSS. Vapor phase PCB fluxes were divided by ambient air concentrations measured with a high volume sampler to calculate overall gas phase PCB mass transfer coefficients (KG). The calculated average PCB MTC was 0.54 +/- 0.47 cm s(-1). This experimentally determined average gas phase overall mass transfer coefficient, KG, agreed well with the ones reported from studies using similar techniques and agreed well with modeled values obtained using MTC correlations developed for the WSS. (c) 2006 Elsevier Ltd. All rights reserved

Effect of fine to coarse aggregate ratio on the rheology and fracture energy of steel fibre reinforced self-compacting concretes

In this study, the influence of aggregate grading and steel fibre properties on the flow properties and fracture energy of steel fibre reinforced self-compacting concrete (SFRSCC) has been investigated. Two types of hooked-end steel fibres at three different dosages (20,40 and 60 kg/m(3)) were incorporated into self-compacting mixtures having similar paste contents but different fine to coarse aggregate (FA/CA) ratios (0.94, 1.72 and 2.50 by weight). Besides the flowability and passing ability of fresh concrete, the mechanical properties of hardened concrete including the fracture energy have also been investigated. The relations between flexural parameters and fibre orientation were established by image analysis technique. Test results showed that hooked-end steel fibre inclusion into the plain self-compacting concrete negatively affects the flowability and passing ability of the mixture. Increasing FA/CA ratio enhances these rheological parameters and provides better fibre orientation. On the other hand, increasing FA/CA ratio decreases the fracture energy of plain SCC mixtures and the fibre incorporated series which were less affected from fibre inclusion follow the same trend with the plain SCC. The proper FA/CA ratio for the best rheological and mechanical performance depends on the fibre content, aspect ratio and their influence on the flowability of the mixture. In order to obtain better fibre orientation and hence higher fracture energy, relatively higher FA/CA ratios should be used when the fibre content and aspect ratio are relatively high

Influence of an aerobic selector on copper and hexavalent chromium biosorption by activated sludge

The definitive version may be found at www.wiley.comUfuk Alkan, Siddik Cindoruk, Yücel Tasdemir, Christopher Colb