Neurobiology of Avoidant/Restrictive Food Intake Disorder in Youth with Overweight/Obesity Versus Healthy Weight

Objective: Avoidant/restrictive food intake disorder (ARFID) occurs across the weight spectrum, however research addressing the coexistesnce of ARFID with overweight/obesity (OV/OB) is lacking. We aimed to establish co-occurrence of OV/OB and ARFID and to characterize divergent neurobiological features of ARFID by weight. Method: Youth with full/subthreshold ARFID (12 with healthy weight [HW], 11 with OV/OB) underwent fasting brain fMRI scan while viewing food/non-food images (M age = 16.92 years, 65% female, 87% white). We compared groups on BOLD response to high-calorie foods (HCF) (vs. objects) in food cue processing regions of interest. Following fMRI scanning, we evaluated subjective hunger pre- vs. post-meal. We used a mediation model to explore the association between BMI, brain activation, and hunger. Results: Participants with ARFID and OV/OB demonstrated significant hyperactivation in response to HCF (vs. objects) in the orbitofrontal cortex (OFC) and anterior insula compared with HW participants with ARFID. Mediation analysis yielded a significant indirect effect of group (HW vs. OV/OB) on hunger via OFC activation (effect = 18.39, SE = 11.27, 95% CI [−45.09, −3.00]), suggesting that OFC activation mediates differences in hunger between ARFID participants with HW and OV/OB. Conclusions: Compared to youth with ARFID and HW, those with OV/OB demonstrate hyperactivation of brain areas critical for the reward value of food cues. Postprandial changes in subjective hunger depend on BMI and are mediated by OFC activation to food cues. Whether these neurobiological differences contribute to selective hyperphagia in ARFID presenting with OV/OB and represent potential treatment targets is an important area for future investigation

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 particle phase dry polychlorinated biphenyls (PCBs) with deposition fluxes of a water surface sampler

It has been shown that the atmospheric pathways including dry deposition are an important source of polychlorinated biphenyls (PCBs) entering surface waters in many locations. To assess how important this pathway is, accurate measurements or modeled estimates of dry deposition are needed. However, dry deposition is not well quantified because the direct measurement of dry deposition is difficult and indirect estimation techniques have substantial uncertainties associated with them. In this study, PCB dry deposition fluxes were directly measured with a water surface sampler (WSS) simultaneously with measurements of airborne concentrations in the Chicago urban area. The average particulate phase PCB flux to the WSS was 240 +/- 160 ng/m(2)-d, and the particulate phase airborne concentrations was 0.08 +/- 0.05 ng/m(3). Average overall dry deposition velocities, calculated by dividing the fluxes by total particle phase PCB concentrations were 4.2 +/- 2.7cm/s. This number is consistent with values determined using similar experimental techniques and higher than the values typically used to model PCB dry deposition. This difference may be due, in part, to the influence of PCBs associated with large particles being deposited onto the WSS. (c) 2005 Elsevier Ltd. All rights reserved

Gas-phase deposition of polychlorinated biphenyls (PCBs) to a water surface sampler

In this study a water surface sampler (WSS) was utilized to directly measure gas phase deposition of polychlorinated biphenyls (PCBs). The measured gas phase PCB fluxes averaged about 880 +/- 660 ngm(-2)d(-1), which was higher than the fluxes calculated using simultaneously measured air and water concentrations for natural surface waters. These large fluxes were due to fact that the measured fluxes were only in the absorption direction since deposited PCBs were continuously removed from the system using an XAD column resulting in the maximum possible flux rate from the air to the WSS water. Ambient air PCBs were also sampled simultaneously with a modified high volume sampler. The gas phase PCB concentrations changed between 0.90 and 4.46 ngm(-3) (2.18 +/- 1.16 ngm(-3)). The mass transfer coefficients (MTCs), calculated by dividing the fluxes by the gas phase concentrations was 0.40 +/- 0.36 cms(-1). The average MTC was comparable with those calculated using a similar configuration of a WSS

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

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

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