Carbonaceous Aerosols in Contrasting Atmospheric Environments in Greek Cities: Evaluation of the EC-tracer Methods for Secondary Organic Carbon Estimation

This study examines the carbonaceous-aerosol characteristics at three contrasting urban environments in Greece (Ioannina, Athens, and Heraklion), on the basis of 12 h sampling during winter (January to February 2013), aiming to explore the inter-site differences in atmospheric composition and carbonaceous-aerosol characteristics and sources. The winter-average organic carbon (OC) and elemental carbon (EC) concentrations in Ioannina were found to be 28.50 and 4.33 µg m−3, respectively, much higher than those in Heraklion (3.86 µg m−3 for OC and 2.29 µg m−3 for EC) and Athens (7.63 µg m−3 for OC and 2.44 µg m−3 for EC). The winter OC/EC ratio in Ioannina (6.53) was found to be almost three times that in Heraklion (2.03), indicating a larger impact of wood combustion, especially during the night, whereas in Heraklion, emissions from biomass burning were found to be less intense. Estimations of primary and secondary organic carbon (POC and SOC) using the EC-tracer method, and specifically its minimum R-squared (MRS) variant, revealed large differences between the sites, with a prevalence of POC (67–80%) in Ioannina and Athens and with a larger SOC fraction (53%) in Heraklion. SOC estimates were also obtained using the 5% and 25% percentiles of the OC/EC data to determine the (OC/EC)pri, leading to results contrasting to the MRS approach in Ioannina (70–74% for SOC). Although the MRS method provides generally more robust results, it may significantly underestimate SOC levels in environments highly burdened by biomass burning, as the fast-oxidized semi-volatile OC associated with combustion sources is classified in POC. Further analysis in Athens revealed that the difference in SOC estimates between the 5% percentile and MRS methods coincided with the semi-volatile oxygenated organic aerosol as quantified by aerosol mass spectrometry. Finally, the OC/Kbb+ ratio was used as tracer for decomposition of the POC into fossil-fuel and biomass-burning components, indicating the prevalence of biomass-burning POC, especially in Ioannina (77%)

Standard addition HPLC method for the determination of a-tocopherol in plasma samples of adolescent swimmers

Vitamin E (a-tocopherol, a-Toc) has been widely used as a powerful antioxidant that protects against oxidation of cellular components. It is used to treat muscular dystrophies, menstrual cycle disorders, risks of pregnancy interruption and abnormalities of gonadal function in men. It is also used frequently from athletes as nutritional supplement for performance enhancing. A simple HPLC method has been validated for the determination of a-Toc in human plasma, using a Nova-Pack analytical column. The chromatographic run time was less than 12 minutes using a mobile phase of Acetonitrile-Methanol 85:15 (v/v), at 0.999 mL/min flow rate while UV/Vis detector was adjusted at 292 nm. The purpose of this study was to evaluate two different approaches for the construction of the calibration curve and further quantify samples from swimmer athletes in order to investigate potential quantification differences. It was shown that the existence of a-Toc as endogenous compounds might affect the actual concentrations and should be considered as an essential parameter during the development of a bioanalytical method for the determination of a-tocopherol in human plasma

Standard addition HPLC method for the determination of a-tocopherol in plasma samples of adolescent swimmers

Vitamin E (a-tocopherol, a-Toc) has been widely used as a powerful antioxidant that protects against oxidation of cellular components. It is used to treat muscular dystrophies, menstrual cycle disorders, risks of pregnancy interruption and abnormalities of gonadal function in men. It is also used frequently from athletes as nutritional supplement for performance enhancing. A simple HPLC method has been validated for the determination of a-Toc in human plasma, using a Nova-Pack analytical column. The chromatographic run time was less than 12 minutes using a mobile phase of Acetonitrile-Methanol 85:15 (v/v), at 0.999 mL/min flow rate while UV/Vis detector was adjusted at 292 nm. The purpose of this study was to evaluate two different approaches for the construction of the calibration curve and further quantify samples from swimmer athletes in order to investigate potential quantification differences. It was shown that the existence of a-Toc as endogenous compounds might affect the actual concentrations and should be considered as an essential parameter during the development of a bioanalytical method for the determination of a-tocopherol in human plasma

A network intervention that locates and intervenes with recently HIV-infected persons: The Transmission Reduction Intervention Project (TRIP).

Early treatment, soon after infection, reduces HIV transmissions and benefits patients. The Transmission Reduction Intervention Project (TRIP) evaluated a network intervention to detect individuals recently infected (in the past 6 months). TRIP was conducted in Greece (2013-2015) and focused on drug injector networks. Based on HIV status, testing history, and the results of an assay to detect recent infections, TRIP classified drug injector Seeds into groups: Recent Seeds (RS), and Control Seeds with Long-term HIV infection (LCS). The network members of RS and LCS were traced for two steps. The analysis included 23 RS, 171 network members of the RS, 19 LCS, and 65 network members of the LCS. The per-seed number of recents detected in the network of RS was 5 times the number in the network of LCS (Ratio RS vs. LCS: 5.23; 95% Confidence Interval (CI): 1.54-27.61). The proportion of recents among HIV positives in the network of RS (27%) was approximately 3 times (Ratio RS vs. LCS: 3.30; 95% CI: 1.04-10.43) that in the network of LCS (8%). Strategic network tracing that starts with recently infected persons could support public health efforts to find and treat people early in their HIV infection