Uncertainty estimation of end-member mixing using generalized likelihood uncertainty estimation (GLUE), applied in a lowland catchment

End-member mixing models have been widely used to separate the different components of a hydrograph, but their effectiveness suffers from uncertainty in both the identification of end-members and spatiotemporal variation in end-member concentrations. In this paper, we outline a procedure, based on the generalized likelihood uncertainty estimation (GLUE) framework, to more inclusively evaluate uncertainty in mixing models than existing approaches. We apply this procedure, referred to as G-EMMA, to a yearlong chemical data set from the heavily impacted agricultural Lissertocht catchment, Netherlands, and compare its results to the traditional end-member mixing analysis (EMMA). While the traditional approach appears unable to adequately deal with the large spatial variation in one of the end-members, the G-EMMA procedure successfully identified, with varying uncertainty, contributions of five different end-members to the stream. Our results suggest that the concentration distribution of effective end-members, that is, the flux-weighted input of an end-member to the stream, can differ markedly from that inferred from sampling of water stored in the catchment. Results also show that the uncertainty arising from identifying the correct end-members may alter calculated end-member contributions by up to 30%, stressing the importance of including the identification of end-members in the uncertainty assessment

Interactions of amphiphilic calix[4]arene-based Solid Lipid Nanoparticles with bovine serum albumin.

International audienceThe interaction of Solid Lipid Nanoparticles (SLN) based on amphiphilic calix[4]arene with one of the major circulatory protein, serum albumin, has been investigated by Photon Correlation Spectroscopy (PCS) and Atomic Force Microscopy (AFM). The carrier systems have shown the ability to interact with bovine serum albumin (BSA), which forms a capping layer up to 17nm in depth. AFM imaging revealed that the SLNs are protected by this layer against flattening on surfaces.The interaction of Solid Lipid Nanoparticles (SLN) based on amphiphilic calix[4]arene with one of the major circulatory protein, serum albumin, has been investigated by Photon Correlation Spectroscopy (PCS) and Atomic Force Microscopy (AFM). The carrier systems have shown the ability to interact with bovine serum albumin (BSA), which forms a capping layer up to 17nm in depth. AFM imaging revealed that the SLNs are protected by this layer against flattening on surfaces

A study of the freeze-drying conditions of calixarene based solid lipid nanoparticles.

International audienceIn this note, we report a study of cryoprotectant carbohydrate (glucose, fructose, mannose and maltose) effects on the reconstitution of calixarene based solid lipid nanoparticle (SLN) suspensions after freeze-drying, studied by atomic force microscopy and photon correlation spectroscopy. All carbohydrates tested showed excellent cryoprotection and redispersion properties with the calixarene based SLNs.In this note, we report a study of cryoprotectant carbohydrate (glucose, fructose, mannose and maltose) effects on the reconstitution of calixarene based solid lipid nanoparticle (SLN) suspensions after freeze-drying, studied by atomic force microscopy and photon correlation spectroscopy. All carbohydrates tested showed excellent cryoprotection and redispersion properties with the calixarene based SLNs

Solid lipid nanoparticles (SLNs): Preparation and properties of calix[4]resorcinarene-derived systems

International audiencexx

Determination of the 13C Contents of Organic Acids and Sugars in Fruit Juices. An Intercomparison Study.

Abstract not availableJRC.I - Institute for Health and Consumer Protection (Ispra

AFM imaging of calixarene based solid lipid nanoparticles in gel matrices.

International audienceContact mode atomic force microscopy has been carried out on gels of four current polymers, carbopol 980, carbopol 2020, hyaluronic acid and xanthan containing dispersions of solid lipid nanoparticles (SLNs) of amphiphilic calixarenes. Imaging shows that the SLNs are dispersed within the gels as discrete particles of 150nm in diameter and show little or no aggregation. The simultaneous use of lateral force, topographic and force modulation mode imaging allows a clear interpretation of the observed images, showing the presence of nanoparticles in the sub-surface region and that the SLNs affect the local mechanical properties of the gels. Photon correlation spectroscopy similarly demonstrates a lack of interaction in suspensions.Contact mode atomic force microscopy has been carried out on gels of four current polymers, carbopol 980, carbopol 2020, hyaluronic acid and xanthan containing dispersions of solid lipid nanoparticles (SLNs) of amphiphilic calixarenes. Imaging shows that the SLNs are dispersed within the gels as discrete particles of 150nm in diameter and show little or no aggregation. The simultaneous use of lateral force, topographic and force modulation mode imaging allows a clear interpretation of the observed images, showing the presence of nanoparticles in the sub-surface region and that the SLNs affect the local mechanical properties of the gels. Photon correlation spectroscopy similarly demonstrates a lack of interaction in suspensions

Saltwater intrusion and water management in the unconfined coastal aquifer of Ravenna (Italy): a numerical model

The Ravenna pine forests represent an historical landmark in the Po River Plain. They have great environmental, historical and tourist value. The San Vitale pine for- est is located 10 km north of the town. It is surrounded by an urban area, the city indus- trial infrastructure and the waterworks of the agricultural drainage system. Most land in this area is below mean sea level. As a result, no natural freshwater hydraulic gradient contrasts the density gradient of saltwater. In the last century, many events (land subsi- dence; land reclamation and drainage; urban and industrial development and gas and deep groundwater extractions; coastal dune destruction) led to the intrusion of large vol- umes of brackish and saline groundwater. Today the freshwater in this coastal aquifer con- sists of low salinity water lenses floating on the saltwater wedge. This study is aimed at understanding how past and present human activities have affected the saltwater intru- sion process in the phreatic aquifer and how the predicted future sea level rise will affect the salinisation process. We used a numerical model to quantify these effects on the den- sity-dependent groundwater flow, hydraulic head and salinity distribution, seepage and salt load fluxes to the surface water system. The simulations show that over the last cen- tury artificial subsidence and heavy drainage started the salinisation process in the study area and a relative sea level rise will accelerate the increase in salt load in the coming decades, affecting the entire aquifer. Climatic conditions in the area result in limited pre- cipitations throughout the year and preclude efficient aquifer recharge, especially in spring and summer when saltwater seepage is extensive. The lack of a continuous coastal dune system favors salt wedge intrusion

A systems perspective for climate adaptation in deltas

Deltas are complex and are among the most vulnerable landforms under climate change. Studying them collectively highlights common stressors that drive their most significant challenges. A holistic conceptual framing of a delta and its feeding river basin is fundamental to effective adaptation planning

Determining the relation between groundwater flow velocities and measured temperature differences using active heating-distributed temperature sensing

Active Heating-Distributed Temperature Sensing (AH-DTS) has the potential to allow for the measurement of groundwater flow velocities in situ. We placed DTS fiber-optic cables combined with a heating wire in direct contact with aquifer sediments in a laboratory scale groundwater flow simulator. Using this setup, we empirically determined the relationship between ΔT, the temperature difference by constant and uniform heating of the DTS cable and the background temperature of the groundwater system, and horizontal groundwater flow velocity. Second, we simulated the observed temperature response of the system using a plan-view heat transfer flow model to calibrate for the thermal properties of the sediment and to optimize cable setup for sensitivity to variation in groundwater flow velocities. Additionally, we derived an analytical solution based on the heat flow equation that can be used to explicitly calculate flow velocity from measured ΔT for this specific AH-DTS cable setup. We expect that this equation, after calibration for cable constitution, is valid for estimating groundwater flow velocity based on absolute temperature differences measured in field applications using this cable setup.</p