Coupling of nitric acid digestion and anion-exchange resin separation for the determination of methylmercury isotopic composition within organisms.

Isotope ratios of methylmercury (MeHg) within organisms can be used to identify sources of MeHg that have accumulated in food webs, but these isotopic compositions are masked in organisms at lower trophic levels by the presence of inorganic mercury (iHg). To facilitate measurement of MeHg isotope ratios in organisms, we developed a method of extracting and isolating MeHg from fish and aquatic invertebrates for compound-specific isotopic analysis involving nitric acid digestion, batch anion-exchange resin separation, and pre-concentration by purge and trap. Recovery of MeHg was quantified after each step in the procedure, and the average cumulative recovery of MeHg was 93.4 ± 2.9% (1 SD, n = 28) for biological reference materials and natural biota samples and 96.9 ± 1.8% (1 SD, n = 5) for aqueous MeHgCl standards. The amount of iHg impurities was also quantified after each step, and the average MeHg purity was 97.8 ± 4.3% (1 SD, n = 28) across all reference materials and natural biota samples after the final separation step. Measured MeHg isotopic compositions of reference materials agreed with literature values obtained using other MeHg separation techniques, and MeHg isotope ratios of aqueous standards, reference materials, and natural biota samples were reproducible. On average, the reproducibility associated with reference material process replicates (2 SD) was 0.10‰ for δ202MeHg and 0.04‰ for Δ199MeHg. This new method provides a streamlined, reliable technique that utilizes a single sample aliquot for MeHg concentration and isotopic analysis. This promotes a tight coupling between MeHg concentration, %MeHg, and Hg isotopic composition, which may be especially beneficial for studying complex food webs with multiple isotopically distinct sources of iHg and/or MeHg.

Use of sequential extraction and mercury stable isotope analysis to assess remobilization of sediment-bound legacy mercury.

The goal of this project was to assess how anthropogenic legacy mercury (Hg) retained in streambed sediment may be remobilized to stream water. To do this, we performed sequential extractions and Hg isotope analyses on streambed sediment collected along the length of East Fork Poplar Creek, a point-source contaminated stream in Oak Ridge, Tennessee, USA. Legacy Hg within streambed sediment appears to have been isotopically fractionated by equilibrium isotope effects driven by isotope exchange between co-existing Hg(0) and Hg(ii) species, potentially over-printing fractionation patterns that would have been imparted by kinetic redox reactions. Weakly-bound and recalcitrant sediment Hg pools were isotopically similar to one another, suggesting that small amounts of recalcitrant Hg may be released and then rapidly and weakly re-adsorbed onto the sediment. This weakly-bound Hg pool appears to contribute dissolved Hg to the hyporheic pore water, which may subsequently enter the surface flow. The isotopic composition of the organically-bound sediment Hg pools, as well as biofilm and suspended particulates, converged with that of the weakly-bound and recalcitrant sediment Hg pools along the flow path. This appears to be indicative of both physical mixing with streambed sediment and the transfer of weakly-bound sediment Hg into biofilm and suspended particulates, followed by re-incorporation into the organically-bound sediment Hg pool. Overall, these results provide evidence that legacy Hg in the streambed is remobilized, enters the stream water as dissolved Hg, and may be incorporated into streambed biofilm, which constitutes a basal resource within the stream ecosystem.

Evaluation of an integrated housing and recovery model for people with severe and persistent mental illnesses: the Doorway program.

Objective The Doorway program is a 3-year pilot integrated housing and recovery support program aimed at people with a severe and persistent mental illness who are 'at risk' or actually homeless. Participants source and choose properties through the open rental market, with appropriate rental subsidy and brokerage support. This arrangement is highly innovative, differing from widely favoured arrangements internationally involving congregate and scattered-site housing owned or managed by the support program. The aim of the present study was to determine the effects of the Doorway program on participants' health, housing, service utilisation and costs. Methods A pre-post study design was used with outcome measures consisting of a number of question inventories and their costs (where relevant). The principal inventories were the Behaviour and Symptom Identification Scale 32 (BASIS-32), a consumer-oriented, self-report measure of behavioural symptoms and distress, the Health of the Nation Outcome Scale (HoNOS), an interviewer-administered measurement tool designed to assess general health and social functioning of mentally ill people and the Outcomes Star (Homelessness) system which measures various aspects of the homelessness experience. Baseline measurements were performed routinely by staff at entry to the program and then at 6-monthly intervals across the evaluation period. Results For 55 of 59 participants, total mean BASIS-32 scores (including as well three of five subscale scores) improved significantly and with moderate effect size. Four of the 10 domain scores on the Outcome Star (Homelessness) inventory also improved significantly, with effect sizes ranging from small-medium (three domains) to large (one domain). Mean usage of bed-based mental health clinical services and general hospital admissions both significantly decreased (with overall net savings of A$3096 per participant per annum). Overall cost savings (including housing) to government ranged from A$1149 to A$19837 depending on the housing type comparator. Conclusion The Doorway program secured housing for this vulnerable group with additional benefits in client outcomes, including reduced use and cost of health services. These findings, if confirmed in larger studies, should have widespread applicability internationally. What is known about the topic? Beneficial effects of housing and recovery programs (Housing First) on people with severe and persistent mental illness and who are 'at risk', or actually homeless, are being demonstrated in Northern America. These effects include housing security, well being, health service utilisation and cost effects on government. However, these beneficial effects can only be regarded as settled for housing security. The highly innovative Doorway care model in which participants source and choose properties through the open rental market, with appropriate rental subsidy and brokerage support, has not been investigated previously. What does this paper add? This paper adds new data on the Doorway care models, it's effects and costs, particularly with regard to participant behavioural distress and social functioning. What are the implications for practitioners? The beneficial effects of this innovative model, if confirmed in larger studies, should have widespread applicability internationally.

Promoting recovery via an integrated model of care to deliver a bed-based, mental health prevention and recovery centre.

OBJECTIVE: This research was conducted in order to explore the experience of care and outcomes for people entering a bed-based step-up/step-down Prevention and Recovery Centre (PARC). METHODS: An audit of files for PARC participants in 2010 collected demographic (age, gender, and marital, housing, employment and education/training status) and clinical measures (length of stay, entry and exit outcome measures, psychiatric hospital use). Participants were also invited to a feedback group to discuss their PARC experience. RESULTS: In 2010, 118 people entered PARC. Most were single and unemployed and 35% were in temporary housing or homeless. In the six months following PARC exit, participants spent significantly less time in psychiatric hospital than in the six months prior to entry (p<0.001). Significant reductions in clinician-rated difficulties were documented at exit (p<0.001). For 40 episodes of care with self-report measures at entry and exit, significant reductions in difficulties with relating to self/others (p=0.004), daily living/role functioning (p=0.006), and depression/anxiety (p=0.019) were seen. Twelve participants attended a feedback group. Positive aspects of PARC included: supportive and caring staff; help with practical issues or community access; therapeutic activities and learning about health; and socialization opportunities. CONCLUSIONS: A step-up/step-down PARC can facilitate recovery for people with mental illness through promoting independence and illness self-management.

What is needed to deliver collaborative care to address comorbidity more effectively for adults with a severe mental illness?

OBJECTIVE: Innovative models of care for people with a severe mental illness have been developed across Australia to more effectively address comorbidity and disability by enhancing the collaboration between clinical and non-clinical services. In particular, this review paper focuses on collaboration that has occurred to address comorbidities affecting the following domains: homelessness; substance addiction; physical ill-health; unemployment; and forensic issues. METHOD: The identification of relevant collaborative care models was facilitated by carrying out a review of the published peer-reviewed literature and policy or other published reports available on the Internet. Contact was also made with representatives of the mental health branches of each Australian state and territory health department to assist in identifying examples of innovative collaborative care models established within their jurisdiction. RESULTS: A number of nationally implemented and local examples of collaborative care models were identified that have successfully delivered enhanced integration of care between clinical and non-clinical services. Several key principles for effective collaboration were also identified. Governmental and organisational promotion of and incentives for cross-sector collaboration is needed along with education for staff about comorbidity and the capacity of cross-sector agencies to work in collaboration to support shared clients. Enhanced communication has been achieved through mechanisms such as the co-location of staff from different agencies to enhance sharing of expertise and interagency continuity of care, shared treatment plans and client records, and shared case review meetings. Promoting a 'housing first approach' with cross-sector services collaborating to stabilise housing as the basis for sustained clinical engagement has also been successful. CONCLUSIONS: Cross-sector collaboration is achievable and can result in significant benefits for mental health consumers and staff of collaborating services. Expanding the availability of collaborative care across Australia is therefore a priority for achieving a more holistic, socially inclusive, and effective mental health care system.

The S-cone contribution to luminance depends on the M- and L-cone adaptation levels: silent surrounds?

Under dim background conditions, the S-cones make little or no contribution to luminance (A. Eisner & D. I. MacLeod, 1980; W. Verdon & A. J. Adams, 1987), yet under conditions of intense long-wavelength adaptation, a small but robust contribution to luminance--as defined by heterochromatic flicker photometry (A. Stockman, D. I. MacLeod, & D. D. DePriest, 1987, 1991) or motion (J. Lee & C. F. Stromeyer, 1989)--can be found. Here, by using selective adaptation and/or tritanopic metamers to isolate the S-cone response, we investigate the dependence of the S-cone luminance input on changes in background wavelength and radiance. Interestingly, the S-cone luminance input disappears completely when no adapting background is present, even though the same S-cone stimulus makes a clear contribution to luminance when a background is present. The dependence of the S-cone luminance input on the wavelength and radiance of the adapting background is surprising. We find that the S-cone signal can be measured on fields of 491 nm and longer wavelengths that exceed a criterion background radiance. These criterion radiances roughly follow an L + M spectral sensitivity, which suggests that the S-cone luminance input is silent unless the L- and M-cones are excited above a certain level. We hypothesize that the L + M cone signals produced by the steady adapting backgrounds somehow "gate" the S-cone luminance signals, perhaps by being modulated by them.