Half-lives of PFOS, PFHxS and PFOA after end of exposure to contaminated drinking water.

BACKGROUND: Municipal drinking water contaminated with perfluorinated alkyl acids had been distributed to one-third of households in Ronneby, Sweden. The source was firefighting foam used in a nearby airfield since the mid-1980s. Clean water was provided from 16 December 2013. OBJECTIVE: To determine the rates of decline in serum perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), and their corresponding half-lives. METHODS: Up to seven blood samples were collected between June 2014 and September 2016 from 106 participants (age 4-84 years, 53% female). RESULTS: Median initial serum concentrations were PFHxS, 277 ng/mL (range 12-1660); PFOS, 345 ng/mL (range 24-1500); and PFOA, 18 ng/mL (range 2.4-92). The covariate-adjusted average rates of decrease in serum were PFHxS, 13% per year (95% CI 12% to 15%); PFOS, 20% per year (95% CI 19% to 22%); and PFOA, 26% per year (95% CI 24% to 28%). The observed data are consistent with a first-order elimination model. The mean estimated half-life was 5.3 years (95% CI 4.6 to 6.0) for PFHxS, 3.4 years (95% CI 3.1 to 3.7) for PFOS and 2.7 years (95% CI 2.5 to 2.9) for PFOA. The interindividual variation of half-life was around threefold when comparing the 5th and 95th percentiles. There was a marked sex difference with more rapid elimination in women for PFHxS and PFOS, but only marginally for PFOA. CONCLUSIONS: The estimated half-life for PFHxS was considerably longer than for PFOS and PFOA. For PFHxS and PFOS, the average half-life is shorter than the previously published estimates. For PFOA the half-life is in line with the range of published estimates

Technical Report - Half-lives of PFOS, PFHxS and PFOA after end of exposure to contaminated drinking water

The present knowledge on PFAS elimination in humans after the end of a dominating source of exposure is scarce. For PFOS and PFHxS only data from fluorochemical workers exist, while a few studies in general populations have reported data for PFOA after end of exposure by drinking water. We here report the first results of analyses of half-life for PFOS, PFHxS and PFOA in a Swedish general population with high exposure in drinking water following cessation of exposure, and compare with hitherto unpublished data on PFOS and PFOA elimination from the C8 study in Ohio, USA. Among 106 persons observed between 6 and 33 months after end of exposure to contaminated drinking water, the shortest half-life was observed for PFOA, mean 2.7 years. The half-life for PFHxS was twice as long, 5.3 years. For PFOS the mean was 3.4 years. The interindividual variation was substantial, with a threefold difference between the 5 and 95 percentiles. In addition, there were also a few extreme outliers. The estimates are well in line with observations in retired fluorocarbon workers, and with observations on PFOA half-live from the C8 study

Sharing knowledge: Final-year healthcare students working together at an interprofessional training ward

Background Healthcare students must learn how to collaborate with colleagues from different professional backgrounds and organisational units. Research has showed what students themselves think they gain from interprofessional education. Less is known about what knowledge students share when doing interprofessional education. Purpose This paper aims to study students’ knowledge sharing when working together as an interprofessional team at an interprofessional training ward. Method The study was conducted using a focused ethnographic approach. Field observations were carried out at two different interprofessional training wards. Fieldnotes, drawings and informal interviews constitute data. Data was analysed iteratively with ‘practice architectures’ as theoretical lens. Discussion/conclusion We found that students share knowledge in different ways during ward rounds, at the student team room and during the reflection session. The ward rounds are more formal and structured; at the student team room, things are buzzing; and the reflection session is weary

Lappeenranta City Bus Cycle

Report of Lappeenranta city bus cycle: Lappeenranta Route 1 Address of Description document: http://www.doria.fi/bitstream/handle/10024/93685/NBNfi-fe201311117322.pdf?sequence=

Cost minimization of a permanent magnet Eddy Current brake by multiobjective particle swarm optimization based on nonlinear reluctance network modeling

Design optimization of a permanent magnet eddy current brake (PM-ECB) is performed by applying multiobjective particle swarm optimization (MO-PSO) for cost minimization. A previously designed and patented PM-ECB is used as a reference model in the study. A quasi-3-dimensional (3D) analytical modeling approach based on a reluctance network considering the actual structure of the reference PM-ECB is proposed and verified. The Gauss-Seidel method is used as a nonlinear solver for the reluctance network modeling, and the braking torque is calculated considering both the skin effect and the armature reaction. Multiobjective optimization is developed by applying a particle swarm algorithm, and a 3D Pareto front is provided to demonstrate all non-dominating design points. Three cost functions, viz. rated braking torque, magnet mass, and magnetic flux density of the yoke, are selected as the objectives for the optimization problem, and the optimum design point is addressed in detail. The optimized design is validated by 3D-FEA and experiments. The results indicate that a 40% reduction in the magnet volume could be brought about by the optimized PM-ECB design with practically the same braking torque. Further, a 40% cost reduction in the optimized brake could be achieved compared with the reference one

Students’ Interprofessional Collaboration in Clinical Practice : Ways of Organizing the Patient Encounter

As health care increases its focus on collaborative practice, universities must provide students with opportunities to learn how to collaborate with different professions and translate this knowledge into practice, known as interprofessional education. Simultaneously, researchers struggle to understand the full complexity of interprofessional education and must therefore conduct multiple-site studies, employ observational work, and apply theory throughout the research process.This paper draws on focused ethnographic fieldwork at two different sites focusing on how students organize collaboration during interprofessional clinical placements. Findings indicate that the way students organize their collaboration is intertwined with how patients were introduced during handovers and involved mobilizing knowledge as “betwixt and between” familiar student practices and unfamiliar clinical practices. Findings also show how authentic situations, artifacts and spatial features supported students to mobilize collaboration.Funding: The study is funded by the Swedish Research Council, 2017-034699.</p

Parameter Selection Guidelines for Direct-on-Line Permanent Magnet Generators Contemplating Fault-Ride-Through Capability

Direct-on-line (DOL) driven permanent-magnet generators (PMSGs) are often applied in small-scale hydropower plants (&#x003C; 10 MW). The Commission Regulation (EU) 2016/631 defines the boundary conditions to operate these generators in parallel with the grid. According to the regulation, fault-ride-through (FRT) capability is required in some cases. FRT scenario of PMSGs was studied by simulations and the importance of machine parameters was analyzed. Machine parameters under interest are damper winding resistance and leakage inductance, stator resistance and leakage inductance, saliency, source voltage, total inductance and system inertia. Authors proved that fault-ride-through can be achieved by utilizing smart machine parameters selection without using complicated control systems and auxiliary equipment. FRT simulations are performed for three PMSGs and their capabilities are explored. Results can be used as a guideline in DOL PMSG design for satisfying FRT requirements. The simulation system was also verified with measurements of a 600 kW PMSG data during a fault situation: an incident where the generator was connected to the grid in phase opposition