Quantitative Structure-Permeation Relationships for Solute Transport Across Silicone Membranes

Purpose. The purpose of this work was to assess the molecular properties that influence solute permeation across silicone membranes and to compare the results with transport across human skin. Methods. The permeability coefficients (log K p) of a series of model solutes across silicone membranes were determined from the analysis of simple transport experiments using a pseudosteady-state mathematical model of the diffusion process. Subsequently, structure-permeation relationships were constructed and examined, focusing in particular on the difference between solute octanol/water and 1,2-dichloroethane/water partition coefficients (Δlog P oct-dce), which reported upon H-bond donor activity, and the computationally derived molecular hydrogen-bonding potential. Results. The hydrogen-bond donor acidity and the lipophilicity of the compounds examined greatly influenced their permeation across silicone membranes. Furthermore, for a limited dataset, a significant correlation was identified between solute permeation across silicone membranes and that through human epidermis. Conclusion. The key molecular properties that control solute permeation across silicone membranes have been identified. For the set of substituted phenols and other unrelated compounds examined here, a similar structure-permeation relationship has been derived for their transport through human epidermis, suggesting application of the results to the prediction of flux across biological barrier

Anatomy of an Alpine Bedload Transport Event: A Watershed‐Scale Seismic‐Network Perspective

The way Alpine rivers mobilize, convey and store coarse material during high-magnitude events is poorly understood, notably because it is difficult to obtain measurements of bedload transport at the watershed scale. Seismic sensor data, evaluated with appropriate seismic physical models, can provide that missing link by yielding time-varying estimates of bedload transport albeit with non-negligible uncertainty. Low cost and ease of installation allow for networks of sensors to be deployed, providing continuous, watershed-scale insights into bedload transport dynamics. Here, we deploy a network of 24 seismic sensors to estimate coarse material fluxes in a 13.4 km2 Alpine watershed during a high-magnitude transport event. First, we benchmark the seismic inversion routine with an independent time-series of bedload transport obtained with a calibrated acoustic system. Then, we apply the procedure to the other seismic sensors across the watershed. Propagation velocities derived from cross-correlation analysis between spatially consecutive bedload transport time-series were too high with respect to typical bedload transport velocity suggesting that a faster-moving water wave (re-)mobilizes local coarse material. Spatially distributed estimates of bedload transport reveal a relative inefficiency of Alpine watersheds in evacuating coarse material, even during a relatively infrequent high-magnitude bedload transport event. Significant inputs estimated for some tributaries were rapidly attenuated as the main river crossed less hydraulically efficient reaches. Only a small proportion of the total amount of material mobilized in the watershed was exported at the outlet. Multiple periods of competent flows are likely necessary to evacuate coarse material mobilized throughout the watershed during individual bedload transport events

Comparison of calibration characteristics of different acoustic impact systems for measuring bedload transport in mountain streams

The Swiss plate geophone (SPG) system has been installed and tested in more than 20 steep gravel-bed streams and rivers, and related studies generally resulted in rather robust calibration relations between signal impulse counts and transported bedload mass. Here, we compare this system with three alternative surrogate measuring systems. A variant of the SPG system uses the same frame (housing) set-up but with an accelerometer instead of a geophone sensor to measure the vibrations of the plate (GP-Acc, for geophone plate accelerometer). The miniplate accelerometer (MPA) system has a smaller dimension of the impact plate and is embedded in more elastomer material than the SPG system. The Japanese pipe microphone (JPM) is a 1 m long version of the system that has been installed in many streams in Japan. To compare the performance of the four systems, we used calibration measurements with direct bedload samples from three field sites and an outdoor flume facility with controlled sediment feed. At our field sites, the systems with an accelerometer and a microphone showed partly large temporal variations in the background noise level, which may have impaired the calibration measurements obtained during certain time periods. Excluding these periods, the SPG, GP-Acc, and JPM all resulted in robust calibration relations, whereas the calibration of the MPA system showed a poorer performance at all sites.</p

Salt Gauging And Stage-Discharge Curve, Avançon De Nant, Outlet Vallon De Nant Catchment

This data set contains the salt gaugings completed over the period 2016 - 2017 to establish a stage-discharge curve at the outlet of the Vallon de Nant catchment. The data set contains also the latest version of the estimated stage-discharge curve, compared to the theoretical curve estimated from the geometric properties of the weir. The salt gaugings have been obtained independently by two different research groups from Institute of Earth Surface Dynamics (IDYST), Faculty of Geosciences and Environement (FGSE), University of Lausanne (UNIL), Stream Biofilm and Ecosystem Research Laboratory (SBER), School of Architecture, Environmental and Civil Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland, The stream gauging station itself was constructed thanks to a joint funding by the Swiss Federal Institute for Forest, Snow and Landscape (WSL), University of Lausanne (chair of Prof. S. Lane) and ETH Zürich (chair of Prof. J. Kirchner). The gauging station is maintained by the Mountain Hydrology and Mass Movements research unit of the Swiss Federal Institute for Forest, Snow and Landscape (WSL) and by the Institute of Earth Surface Dynamics of University of Lausanne

An integrative assessment of the plastic debris load in the Mediterranean Sea

International audienceThe Mediterranean Sea is recognized as one of the most polluted areas by floating plastics. During the Tara Mediterranean expedition, an extensive sampling of plastic debris was conducted in seven ecoregions, from Gibraltar to Lebanon with the aim of providing reliable estimates of regional differences in floating plastic loads and plastic characteristics. The abundance, size, surface, circularity and mass of 75,030 pieces were analyzed and classified in a standardized multi-parameter database. Their average abundance was 2.60 × 105 items km−2 (2.25 × 103 to 8.50 × 106 km−2) resulting in an estimate of about 650 billion plastic particles floating on the surface of the Mediterranean. This corresponds to an average of 660 metric tons of plastic, at the lower end of literature estimates. High concentrations of plastic were observed in the northwestern coastal regions, north of the Tyrrhenian Sea, but also off the western and central Mediterranean basins. The Levantine basin south of Cyprus had the lowest concentrations. A Lagrangian Plastic Pollution Index (LPPI) predicting the concentration of plastic debris was validated using the spatial resolution of the data. The advanced state of plastic degradation detected in the analyses led to the conclusion that stranding/fragmentation/resuspension is the key process in the dynamics of floating plastic in Mediterranean surface waters. This is supported by the significant correlation between pollution sources and areas of high plastic concentration obtained by the LPPI

Underway surface water data during the Tara Oceans expedition in 2009-2012

The Tara Oceans Expedition (2009-2013) sampled the world oceans on board a 36 m long schooner, collecting environmental data and organisms from viruses to planktonic metazoans for later analyses using modern sequencing and state-of-the-art imaging technologies. Tara Oceans Data are particularly suited to study the genetic, morphological and functional diversity of plankton. During the entire expedition (2009-2013), underway measurements were obtained from a meteorological station (BATOS), a thermosalinograph (TSG, SBE 45), a Fast Repetition Rate Flurometer (FRRF, LIFT-FRR01), and a spectrophotometer (WETLabs AC-S). In 2013 underway measurements were enhanced by adding a Photosynthetically Available Radiation (PAR) sensor (QCP2350, Biospherical Instruments, Inc.), a laser spectrofluorometer (WETLabs ALFA, Chekalyuk et al., 2012) that replaced the FRRF, a spectral backscattering sensor (WETLabs Eco-bb3), a pCO2 sensor (ProOceanus CO2-Pro), a pH sensor (Satlantic, SeaFET) and a particle imaging system triggered by chlorophyll-a fluorescence (a prototype of McLane Research Laboratories' Imaging FlowCytobot, Sosik Lab, WHOI). Discrete measurements of CDOM absorption measurements were made using an Ultrapath (WPI Inc.) to calibrate the in-line AC-S. Hence the AC-S was also used to provide CDOM absorption in addition to particulate matter properties. The present dataset contains surface water data measured during the 2009-2012 campaigns of the Tara Oceans Expedition. Latitude and Longitude were obtained from TSG data. The time stamp of this data set is harmonised with that of other underway data in this collection

Underway surface water data during the Tara Oceans expedition in 2013

The Tara Oceans Expedition (2009-2013) sampled the world oceans on board a 36 m long schooner, collecting environmental data and organisms from viruses to planktonic metazoans for later analyses using modern sequencing and state-of-the-art imaging technologies. Tara Oceans Data are particularly suited to study the genetic, morphological and functional diversity of plankton. During the entire expedition (2009-2013), underway measurements were obtained from a meteorological station (BATOS), a thermosalinograph (TSG, SBE 45), a Fast Repetition Rate Flurometer (FRRF, LIFT-FRR01), and a spectrophotometer (WETLabs AC-S). In 2013 underway measurements were enhanced by adding a Photosynthetically Available Radiation (PAR) sensor (QCP2350, Biospherical Instruments, Inc.), a laser spectrofluorometer (WETLabs ALFA, Chekalyuk et al., 2012) that replaced the FRRF, a spectral backscattering sensor (WETLabs Eco-bb3), a pCO2 sensor (ProOceanus CO2-Pro), a pH sensor (Satlantic, SeaFET) and a particle imaging system triggered by chlorophyll-a fluorescence (a prototype of McLane Research Laboratories' Imaging FlowCytobot, Sosik Lab, WHOI). Discrete measurements of CDOM absorption measurements were made using an Ultrapath (WPI Inc.) to calibrate the in-line AC-S. Hence the AC-S was also used to provide CDOM absorption in addition to particulate matter properties. The present dataset contains surface water data measured during the 2013 campaigns of the Tara Oceans Expedition. Latitude and Longitude were obtained from TSG data. The time stamp of this data set is harmonised with that of other underway data in this collection

Harmonised data from underway navigation, meteorology and surface water measurements during the Tara Oceans expedition in 2009-2013

The Tara Oceans Expedition (2009-2013) sampled the world oceans on board a 36 m long schooner, collecting environmental data and organisms from viruses to planktonic metazoans for later analyses using modern sequencing and state-of-the-art imaging technologies. Tara Oceans Data are particularly suited to study the genetic, morphological and functional diversity of plankton. During the entire expedition (2009-2013), underway measurements were obtained from a meteorological station (BATOS), a thermosalinograph (TSG, SBE 45), a Fast Repetition Rate Flurometer (FRRF, LIFT-FRR01), and a spectrophotometer (WETLabs AC-S). In 2013 underway measurements were enhanced by adding a Photosynthetically Available Radiation (PAR) sensor (QCP2350, Biospherical Instruments, Inc.), a laser spectrofluorometer (WETLabs ALFA, Chekalyuk et al., 2012) that replaced the FRRF, a spectral backscattering sensor (WETLabs Eco-bb3), a pCO2 sensor (ProOceanus CO2-Pro), a pH sensor (Satlantic, SeaFET) and a particle imaging system triggered by chlorophyll-a fluorescence (a prototype of McLane Research Laboratories' Imaging FlowCytobot, Sosik Lab, WHOI). Discrete measurements of CDOM absorption measurements were made using an Ultrapath (WPI Inc.) to calibrate the in-line AC-S. Hence the AC-S was also used to provide CDOM absorption in addition to particulate matter properties. The present collection includes three data sets that are harmonised with a common time stamp. The source data sets given in the reference section