A Simple Analytical Model of Evaporation in the Presence of Roots

Root systems can influence the dynamics of evapotranspiration of water out of a porous medium. The coupling of evapotranspiration remains a key aspect affecting overall root behavior. Predicting the evapotranspiration curve in the presence of roots helps keep track of the amount of water that remains in the porous medium. Using a controlled visual set-up of a 2D model soil system consisting of monodisperse glass beads, we first perform experiments on actual roots grown in partially saturated systems under different relative humidity conditions. We record parameters such as the total mass loss in the medium and the resulting position of the receding fronts and use these experimental results to develop a simple analytical model that predicts the position of the evaporating front as a function of time as well as the total amount of water that is lost from the medium due to the combined effects of evaporation and transpiration. The model is based on fundamental principles of evaporation flux and includes empirical assumptions on the quantity of stoma in the leaves and the transition time between regime 1 and regime 2. The model also underscores the importance of a much prolonged root life as long as the root is exposed to a partially saturated zone composed of a mixture of air and water. Comparison between the model and experimental results shows good prediction of the position of the evaporating front as well as the total mass loss from evapotranspiration in the presence of real root systems. These results provide additional understanding of both complex evaporation phenomenon and its influence on root mechanisms.Comment: 10 pages, 6 figure

Submicrometric Films of Surface-Attached Polymer Network with Temperature-Responsive Properties

Temperature-responsive properties of surface-attached poly(N-isopropylacrylamide) (PNIPAM) network films with well-controlled chemistry are investigated. The synthesis consists of cross-linking and grafting preformed ene-reactive polymer chains through thiol--ene click chemistry. The formation of surface-attached and cross-linked polymer films has the advantage of being wellcontrolled without any caution of no-oxygen atmosphere or addition of initiators. PNIPAM hydrogel films with same cross-link density are synthesized on a wide range of thickness, from nanometers to micrometers. The swelling-collapse transition with temperature is studied by using ellipsometry, neutron reflectivity, and atomic force microscopy as complementary surface-probing techniques. Sharp and high amplitude temperature-induced phase transition is observed for all submicrometric PNIPAM hydrogel films. For temperature above LCST, surface-attached PNIPAM hydrogels collapse similarly but without complete expulsion of water. For temperature below LCST, the swelling of PNIPAM hydrogels depends on the film thickness. It is shown that the swelling is strongly affected by the surface attachment for ultrathin films below $\sim$150 nm. For thicker films above 150 nm (to micrometers), surface-attached polymer networks with the same cross-link density swell equally. The density profile of the hydrogel films in the direction normal to the substrate is confronted with in-plane topography of the free surface. It results that the free interface width is much larger than the roughness of the hydrogel film, suggesting pendant chains at the free surface.Comment: in Langmuir, American Chemical Society, 2015, LANGMUIR, 31 (42), pp.11516-1152

Kinetics of Gravity-Driven Water Channels Under Steady Rainfall

We investigate the formation of fingered flow in dry granular media under simulated rainfall using a quasi-2D experimental set-up composed of a random close packing of mono-disperse glass beads. Using controlled experiments, we analyze the finger instabilities that develop from the wetting front as a function of fundamental granular (particle size) and fluid properties (rainfall, viscosity).These finger instabilities act as precursors for water channels, which serve as outlets for water drainage. We look into the characteristics of the homogeneous wetting front and channel size as well as estimate relevant time scales involved in the instability formation and the velocity of the channel finger tip. We compare our experimental results with that of the well-known prediction developed by Parlange and Hill [1976]. This model is based on linear stability analysis of the growth of perturbations arising at the interface between two immiscible fluids. Results show that in terms of morphology, experiments agree with the proposed model. However, in terms of kinetics we nevertheless account for another term that describes the homogenization of the wetting front. This result shows that the manner we introduce the fluid to a porous medium can also influence the formation of finger instabilities.Comment: 13 pages, 7 figure

Semi-industrial development of nutritious and healthy seafood dishes from sustainable species

This study aimed to devise innovative, tailor-made, appealing, tasty and semi-industrialized dishes, using sustainable and under-utilized seafood species (bib, common dab, common carp, blue mussel and blue whiting), that can meet the specific nutritional and functional needs of children (8-10-years), pregnant women (20-40-years) and seniors (≥60-years). Hence, contests were organised among cooking schools from 6 European countries and the best recipes/dishes were reformulated, semi-industrially produced and chemically and microbiologically evaluated. The dishes intended for: (i) children and pregnant women had EPA + DHA and I levels that reached the target quantities, supporting the claim as “high in I”; and (ii) seniors were “high in protein” (24.8%-Soup_S and 34.0%-Balls_S of the energy was provided by proteins), “high in vitamin B12”, and had Na contents (≤0.4%) below the defined limit. All dishes reached the vitamin D target value. Sausages_C, Roulade_P, Fillet_P and Balls_S had a well-balanced protein/fat ratio. Roulade_P presented the highest n-3 PUFA/n-6 PUFA ratio (3.3), while Sausages_C the lowest SFA/UNS ratio (0.2). Dishes were considered safe based on different parameters (e.g. Hg-T, PBDEs, Escherichia coli). All represent dietary sources contributing to meet the reference intakes of target nutrients (33->100%), providing valuable options to overcome nutritional and functional imbalances of the three groups.This project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement no. 773400 (SEAFOODTOMORROW). This work was also supported by the Spanish Ministry of Science and Innovation (Project CEX 2018-000794-S), the Generalitat de Catalunya (Consolidated Research Group Water and Soil Quality Unit 2017 SGR 1404) and Fundação para a Ciência e a Tecnologia (FCT)/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES) through national funds (UID/QUI/50006/2019, UIDB/50006/2020, UIDP/50006/2020, UIDB/04423/2020 and UIDP/04423/2020). The authors also thank FCT and the European Union's H2020 Research and Innovation Programme for funding through the project Systemic - An integrated approach to the challenge of sustainable food systems: adaptive and mitigatory strategies to address climate change and malnutrition. Sara Cunha also acknowledges FCT for the IF/01616/2015 contract. Biotage is acknowledged for providing SPE cartridges and Bekolut for the QuEChERS kits. This output reflects the views only of the author(s), and the European Union cannot be held responsible for any use that may be made of the information contained therein

Reccurrent F8 Intronic Deletion Found in Mild Hemophilia A Causes Alu Exonization

cited By 1; Article in PressInternational audienceIncorporation of distant intronic sequences in mature mRNA is an underappreciated cause of genetic disease. Several disease-causing pseudoexons have been found to contain repetitive elements such as Alu elements. This study describes an original pathological mechanism by which a small intronic deletion leads to Alu exonization. We identified an intronic deletion, c.2113+461₂113+473del, in the F8 intron 13, in two individuals with mild hemophilia A. In vivo and in vitro transcript analysis found an aberrant transcript, with an insertion of a 122-bp intronic fragment (c.2113₂114ins2113+477₂113+598) at the exon 13-14 junction. This out-of-frame insertion is predicted to lead to truncated protein (p.Gly705Aspfs*37). DNA sequencing analysis found that the pseudoexon corresponds to antisense AluY element and the deletion removed a part of the poly(T)-tail from the right arm of these AluY. The heterogenous nuclear riboprotein C1/C2 (hnRNP C) is an important antisense Alu-derived cryptic exon silencer and binds to poly(T)-tracts. Disruption of the hnRNP C binding site in AluY T-tract by mutagenesis or hnRNP C knockdown using siRNA in HeLa cells reproduced the effect of c.2113+461₂113+473del. The screening of 114 unrelated families with mild hemophilia A in whom no genetic event was previously identified found a deletion in the poly(T)-tail of AluY in intron 13 in 54% of case subjects (n = 61/114). In conclusion, this study describes a deletion leading to Alu exonization found in 6.1% of families with mild hemophila A in France. © 2017 American Society of Human Genetics