Arabinoxylan/protein gels : structural, rheological and controlled release properties

International audienc

Particle transport induced by internal wave beam streaming in lateral boundary layers

Quantifying the physical mechanisms responsible for the transport of sediments, nutrients and pollutants in the abyssal sea is a long-standing problem, with internal waves regularly invoked as the relevant mechanism for particle advection near the sea bottom. This study focuses on internal-wave-induced particle transport in the vicinity of (almost) vertical walls. We report a series of laboratory experiments revealing that particles sinking slowly through a monochromatic internal wave beam experience significant horizontal advection. Extending the theoretical analysis by Beckebanze et al. (J. Fluid Mech., vol. 841, 2018, pp. 614-635), we attribute the observed particle advection to a peculiar and previously unrecognized streaming mechanism in the stratified boundary layer originating at the lateral walls. This vertical boundary layer streaming mechanism is most efficient for significantly inclined wave beams, when vertical and horizontal velocity components are of comparable magnitude. We find good agreement between our theoretical prediction and experimental results

Embryo Form Project: An original technique for the three-dimensional reconstruction of human embryo morphology

International audienceOur current knowledge on the developmental stages of human embryogenesis has derived from limited numbers of classical studies. Computer technology now permits accurate 3D reconstruction of embryo morphology from serial histological sections. We present a successful technique that uses either fresh or preserved serial histological sections to generate highly detailed 3D image reconstructions of very small human embryos. We present the data we obtained from the reconstruction in virtual space of previously sectioned 15 and 22.5mm embryos. Their morphologies were studied using a DICOM viewer which permitted the analysis of any specific structure in any required orientation. To our knowledge, this is the first time human embryos have been reconstructed in this way. We believe that this reconstruction technique could improve our knowledge on embryo morphogenesis, especially if coupled to the study of genes involved in embryonic development. It may also prove to be a useful pedagogical tool

Physical characterisation of the rhamnogalacturonan and homogalacturonan fractions of sugar beet (Beta vulgaris) pectin

Acid extracted sugar beet (Beta vulgaris) pectin was subjected to enzymatic hydrolysis using fungal pectin methyl esterase (f-PME) and two endopolygalacturonanases (PGs I and II). From the hydrolysate, the RG-I fraction was separated and purified by chromatographic techniques. This RG-I fraction was shown to be of high weight average molar mass (188,000 g/mol), but low intrinsic viscosity (36 ml/g), which is consistent with a random coil conformation (Lp = 1.4 nm). The HG fraction was prepared by mild acid hydrolysis of acid extracted pectin. The HG fraction was found to have a relatively low weight average molar mass (20,000 g/mol), but a rather high intrinsic viscosity (77 ml/g), which is consistent with the HG fraction being rigid in solution (Lp = 9.8 nm). Lower molar mass pectins are richer in HG regions and pectins of higher molar mass are richer in RG-I regions. We conclude that the degradation of the HG region has an important impact on intrinsic viscosity, but less on molar mass and the inverse is true for the degradation of RG-I region. This has important consequences in terms of the functionality of sugar beet pectin molecules. © 2010 Elsevier Ltd

Physiological Whole-Brain Distribution of [¹⁸F]FDOPA Uptake Index in Relation to Age and Gender: Results from a Voxel-Based Semi-quantitative Analysis.

6-[ <sup>18</sup> F]fluoro-L-DOPA ([ <sup>18</sup> F]FDOPA), a positron emission tomography (PET) amino-acid tracer of brain decarboxylase activity, is used to assess the brain dopaminergic system. Using a voxel-based semi-quantitative analysis, this study aimed to determine whether a current brain uptake index of [ <sup>18</sup> F]FDOPA, expressed relative to the occipital background level, varies according to age and gender. One hundred and seventy-seven subjects were retrospectively included. A whole-brain statistical parametric mapping analysis of the [ <sup>18</sup> F]FDOPA uptake index in parametric PET images was performed at a voxel threshold of p < 0.05 (corrected) and p < 0.005 (uncorrected, k cluster > 125). Striatal uptake indices were influenced by age, negatively for the caudate nucleus and positively for the putamen, as well as by gender, with a lower left putaminal uptake index in women. Extra-striatal uptake indices were influenced by age, negatively for the frontal cortex and brainstem and positively for the occipital cortex and cerebellum, as well as by gender (diffuse increase in women). The uptake index of [ <sup>18</sup> F]FDOPA exhibited significant physiological variations according to age and gender and should therefore be considered for PET interpretation

In vitro digestion of mixed leguminous-wheat pastastudy of residual allergenicity of digestion juices and lipid metabolism in the presence of digests

Many research questions remain open in food area including the relationship between processing, structure and resulting nutritional properties. Wheat pasta, pea puree, a mixed meal and 3 mixed legume-wheat pastas, differently dried to introduce changes in pasta structure, were chosen as model foods to investigate impact of processing on resulting peptide composition of digestion juices and their residual allergenicity and whether lipid metabolismwould be modified in the presence of these digests

La digestibilité protéique des pâtes alimentaires et leur allergénicité sont-elles influencées par le séchage

National audienc

Enzymatically cross-linked arabinoxylan microspheres as oral insulin delivery system

Arabinoxylans (AX) microspheres with different insulin/AX mass ratio were prepared by formation of phenoxy radical issued from the ferulic acid by enzymatic oxidation (entrapped in situ of insulin). Phenolic acid content and FT-IR spectrum of unloaded and insulin-loaded AX microspheres revealed that the phenoxy radical issued from the ferulic acid by enzymatic oxidation did not interact covalently with insulin. The microspheres showed a spherical shape, smooth surface and an average diameter of particles of 320 μm. In vitro control release found that AX microspheres minimized the insulin loss in the upper GI tract, retaining high percentage (~75%) of insulin in its matrix. The stability of the secondary structure of insulin was studied by dichroism circular (CD). The CD spectra of insulin released from AX microspheres did not change according to the insulin/AX mass ratio of the microsphere. Significant hypoglycemic effects with improved insulin-relative bioavailability tested on an in vivo murine model revealed the efficacy of these enzymatically cross-linked arabinoxylans microspheres as a new oral insulin carrier