Hepatitis C in HIV-infected individuals: cure and control, right now

For persons living with HIV, hepatitis C is a major public health problem that must be controlled and could be eliminated. The challenge arises because the hepatitis C virus (HCV) is prevalent among HIV-infected persons in most parts of the world, because HIV worsens all HCV outcomes, and because HCV may add additional individual economic and psychosocial complications to HIV disease. Despite the major benefits of antiretroviral therapy on HIV outcomes, antiretroviral therapy is not sufficient to halt the complications of HCV. Nonetheless, HCV can be controlled at all stages, including prevention of infection and cure. Thus, HCV is an eradicable disease. There are significant inequalities worldwide in HCV control that could markedly constrain the impact of these measures

Constraints from observations and modeling on atmosphere-surface exchange of mercury in eastern North America

Atmosphere-surface exchange of mercury, although a critical component of its global cycle, is currently poorly constrained. Here we use the GEOS-Chem chemical transport model to interpret atmospheric Hg-0 (gaseous elemental mercury) data collected during the 2013 summer Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks (NOMADSS) aircraft campaign as well as ground-and ship-based observations in terms of their constraints on the atmosphere-surface exchange of Hg-0 over eastern North America. Model-observation comparison suggests that the Northwest Atlantic may be a net source of Hg-0, with high evasion fluxes in summer (our best sensitivity simulation shows an average oceanic Hg-0 flux of 3.3 ng m(-2) h(-1) over the Northwest Atlantic), while the terrestrial ecosystem in the summer of the eastern United States is likely a net sink of Hg-0 (our best sensitivity simulation shows an average terrestrial Hg-0 flux of -0.6 ng m(-2) h(-1) over the eastern United States). The inferred high Hg-0 fluxes from the Northwest Atlantic may result from high wet deposition fluxes of oxidized Hg, which are in turn related to high precipitation rates in this region. We also find that increasing simulated terrestrial fluxes of Hg-0 in spring compared to other seasons can better reproduce observed seasonal variability of Hg-0 concentration at ground-based sites in eastern North America.Peer reviewe

Measurement of the vapor phase deposition of polychlorinated bipheyls (PCBs) using a water surface sampler

A water surface sampler (WSS) was employed in combination with greased knife-edge surface deposition plates (KSSs) to measure the vapor phase deposition rates of PCBs to the sampler at an urban site, Chicago, IL. This sampler employed a water circulation system that continuously removed deposited PCBs. Total (gas + particle) and particulate PCB fluxes were collected with the WSS and KSSs, respectively. Gas phase PCB fluxes were then calculated by subtracting the KSS fluxes (particulate) from the WSS fluxes (gas + particle). The calculated gas phase PCB fluxes averaged 830 +/- 910 ng m(-2) d(-1). This flux value is, in general, higher than the fluxes determined using simultaneously measured air-water concentrations in natural waters and is in the absorption direction. This difference is primarily because the PCBs were continuously removed from the WSS water keeping the water PCB concentration near zero. Concurrently, ambient air samples were collected using a modified high volume air sampler. The gas phase PCB concentrations ranged between 1.10 and 4.46 ng m(-3) (average +/- SD, 2.29 +/- 1.28 ng m(-3)). The gas phase fluxes were divided by the simultaneously measured gas phase ambient concentrations to determine the overall gas phase mass transfer coefficients (MTCs) for PCBs. The average gas phase overall MTCs (K.) for each honiolog group ranged between 0.22 and 1.32 cm s(-1) (0.54 +/- 0.47cm s(-1)). The average MTC was in good agreement with those determined using similar techniques

Automated Dry Deposition Sampler

A dry deposition sampling apparatus having at least one thin dry deposition plate with sample collection film is maintained on a support structure which is rotatable about a vertical axis and has a vane to maintain the sharp leading edge of the dry deposition plate(s) headed into the wind. Covers are positioned over the sample collection films automatically upon commencement of precipitation and are automatically moved to a position exposing the sample collection films to the atmosphere upon cessation of precipitation. The duration of exposure of the collection films to the atmosphere is timed, thus providing a dry deposition sampling apparatus which may be left unattended for long periods of time.Sponsorship: Illinois Institute of TechnologyUnited States Paten

Mass transfer coefficients for polycyclic aromatic hydrocarbons (PAHs) to the water surface sampler: Comparison to modeled results

A sampling program was conducted between June and October 1995 in Chicago, IL using a modified water surface sampler (WSS) and dry deposition plates to measure the particulate dry deposition and gas exchange of PAHs. Oxygen transfer experiments were also conducted to evaluate the collection properties of the WSS for gas-phase compounds. Gas-phase fluxes were determined by subtracting the dry deposition plate fluxes (particulate) from WSS fluxes (particulate+gas). These fluxes were divided by concurrently measured ambient concentrations to obtain overall gas phase mass transfer coefficients. Two different two-film models, one developed based on experiments performed with the WSS and, one previously published, were compared to these results. Experimentally determined average gas phase overall mass transfer coefficient (Kg) for seven PAHs was 0.74±0.52cms-1. Experimental Kg values agreed well with those predicted by the model developed for WSS. The values predicted by previously proposed models were within a factor of 3 of the experimental ones

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