Metagenomics: A viable tool for reconstructing herbivore diet

Metagenomics can generate data on the diet of herbivores, without the need for primer selection and PCR enrichment steps as is necessary in metabarcoding. Metagenomic approaches to diet analysis have remained relatively unexplored, requiring validation of bioinformatic steps. Currently, no metagenomic herbivore diet studies have utilized both chloroplast and nuclear markers as reference sequences for plant identification, which would increase the number of reads that could be taxonomically informative. Here, we explore how in silico simulation of metagenomic data sets resembling sequences obtained from faecal samples can be used to validate taxonomic assignment. Using a known list of sequences to create simulated data sets, we derived reliable identification parameters for taxonomic assignments of sequences. We applied these parameters to characterize the diet of western capercaillies (Tetrao urogallus) located in Norway, and compared the results with metabarcoding trnL P6 loop data generated from the same samples. Both methods performed similarly in the number of plant taxa identified (metagenomics 42 taxa, metabarcoding 43 taxa), with no significant difference in species resolution (metagenomics 24%, metabarcoding 23%). We further observed that while metagenomics was strongly affected by the age of faecal samples, with fresh samples outperforming old samples, metabarcoding was not affected by sample age. On the other hand, metagenomics allowed us to simultaneously obtain the mitochondrial genome of the western capercaillies, thereby providing additional ecological information. Our study demonstrates the potential of utilizing metagenomics for diet reconstruction but also highlights key considerations as compared to metabarcoding for future utilization of this technique

Le suivi des expositions professionnelles aux agents chimiques dangereux et aux produits cancérigènes, mutagènes et reprotoxiques dans une industrie chimique

International audienc

Ketoprofen amorphous form. Part 2. Influence on compression behaviour

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Influence of hydration on the mechanical properties of naproxen sodium

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Influence of crystal habit on the compression and densification mechanism of ibuprofen

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Micro- and Nano-Mechanical Characterisation and Modelling of the Local Matrix Deformation in Fibrereinforced Epoxy

The prediction of the deformation and failure of fibre-reinforced polymer composites via bottom-up multi-scale models has become standard in the composite community. The development of accurate computational multi-scale models relies on the proper description, and thus characterisation of the individual components of the composite ply, i.e. fibres, matrix, and interfaces and interphases between the matrix and the fibres. However, the determination of the properties of these constituents at the micro/nano-scale remains a challenge. Additionally, the properties of the matrix are usually defined using continuum constitutive laws. Hence, there is a need for micro-/nano-mechanical characterisation methods to establish the matrix material response at the fibre/matrix level. These challenges place a limit on the accuracy of composite model predictions, even for simple unidirectional (UD) composites loaded in transverse compression or shear, where the matrix dominates the macroscopic deformation response of the composite. In this study, a combined experimental and numerical approach is used to characterise the individual constituents of a UD composite composed of carbon fibres and an epoxy resin. Emphasis is placed on the measurement and prediction of the constitutive response at a length scale close to the fibre diameter, where e.g. matrix size effects may exist. First, the local matrix deformation response in resin-rich pockets within UDs is probed by nanoindentation and atomic force microscopy (AFM). The extracted properties are compared with macro- and micro-scale properties of RTM6 from previous studies. Second, transverse compression tests on UD specimens are conducted inside a scanning electron microscope (SEM). The local strain field around the fibres is quantified using nano digital image correlation on a microscale region of interest (ROI). The DIC strain maps on a ROI are compared with those predicted via FEA using an established continuum model for RTM6.</p

Prévalence des troubles cognitifs et nutritionnels chez les sujets âgés cancéreux évalués en consultation d’oncogériatrie

National audienc

L'UPSAV une interface entre la ville et l'hôpital.

National audienc