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Barriers to participation in an HIV vaccine trial have been examined in many HIV vaccine preparedness studies (VPS). These barriers can be understood in terms of the locus of the barrier (personal vs. social) and the nature of the barrier (risk vs. cost). Another type of barrier is perceived misconceptions. In this systematic review, we categorize barriers, and compare these barriers between the Organization for Economic Co-operation and Development (OECD) countries and the non-OECD countries. In the OECD countries, we retrieved 25 studies reporting personal risks (PR), 9 studies reporting social risks (SR), 10 studies reporting personal costs (PC), and 16 studies reporting misconceptions. In the non-OECD countries, we retrieved 27 studies reporting PR, 19 studies reporting SR, 18 studies reporting PC, 1 study reporting social costs (SC), and 13 studies reporting misconceptions. Important PR were "adverse effects" and "vaccine-induced seropositivity", "distrust of institutions", and "temptation to have unsafe sex" in men who have sex with men (MSM). "Discrimination" was a common SR. "Time commitment" was an important PC, and "family commitments" were a SC in one non-OECD country. "HIV infection from the vaccine" was a common misconception. Both the OECD and the non-OECD countries have similar barriers, and people's decisions to participate in a clinical trial involve multiple barriers. However, these barriers apply to hypothetical HIV vaccine trials, and barriers for actual vaccine trials need further assessment.

A gas chromatography–mass spectrometry isotope dilution (GC–MS ID) method was developed and tested for the determination of 14 common glycol ethers in consumer products. Stable isotope labelled standards, 2-methoxyethanol-D7 and 2-butoxyethanol-13C2 (CDN isotopes) were employed to enhance the accuracy and precision of the glycol ethers determination. A 1000-fold sample dilution with methanol was applied to avoid column overload and contamination. At this dilution matrix effects were in most cases negligible and did not interfere with the analysis. The instrument detection limit (IDL) for analysed compounds varied from 0.01 to 1 μg/mL; while the estimated limit of quantification (LoQ) varied between different glycol ethers from 0.02 to 3.4 μg/mL. Calibration was tested in the range of 0.1–200 μg/mL and showed that the linear fit is upheld from 0.1 to 10 μg/mL, and extends beyond this range for some of the analytes. Recoveries of glycol ethers from products with different matrices were similar. The recoveries varied from 87% to 116% between the analysed compounds, while measurements precision varied between 2% and 14%. The method is applicable to products with glycol ether concentrations above 0.002–0.2% (w/w). The concentration range can be extended below the specified limits by decreasing the dilution factor; however, with lower dilution the sample matrix effect is expected to be stronger. Products with very high concentrations of glycol ether (>20%) may need to be further diluted prior to injection to avoid column overload. The method can be used for testing liquid and aerosol products designed for household use, such as cleaners, paints, solvents and paint stripers, for compliance and enforcement of regulations which limit glycol ethers content.

Weekly filter samples, representing air-borne particles, at Alert, Nunavut, (82°30′N, 62°20′W) collected during the winter of 2000/2001 have been analysed for polychlorinated dibenzo- p- dioxins and dibenzofurans (PCDD/Fs). The sampling period coincided with the occurrence of the Arctic Haze (December–April) when air-borne particulate concentrations are generally high at Alert. Atmospheric phase distribution at average ambient temperature (−28.2°C) estimated using the Junge–Pankow adsorption model and the adsorption model based on octanol–air partition coefficients have shown that most PCDD/F congeners would be particle-bound under such conditions; with particle fractions >90%. The concentrations of both ΣPCDDs and ΣPCDFs observed were lower than those found at Ny-Alesund (78°55′N, 11°56′E) and other locations worldwide. This is attributable to the remoteness of the site and the absence of anthropogenic activities nearby. An apparent peak in concentrations occurred during the third week of 2001 (15–22/1/2001). Weekly averaged 5-day Lagrangian back trajectories have shown that Alert was mainly affected by air originated from North Atlantic and North America during the first week of 2001. The origin of the airmass shifted eastwards further into Russia and Eurasia during the second and third weeks when the air concentrations of PCDD/Fs peaked at Alert. Then, the influence from Eurasia decreased while the North Atlantic sector regained dominance when the concentrations tapered off during the fourth and fifth weeks. In spite of the remoteness of Alert, congener profiles in most samples were enriched with PCDFs, corresponding to “source” profiles as suggested by Wagrowski and Hites (Environ. Sci. Technol. 34 (2000) 2952). Similar profiles were observed in air and tree bark at other Arctic locations. These profiles were probably the result of PCDD/F physical–chemical properties, which influence their transport behaviour between sources and receptors, as well as the unique Arctic environmental conditions. Therefore, the “source” and “sink” homologue profiles generally applicable to sample collected at temperate sites cannot be applied to those collected in the high Arctic.