Synthesis and characterization of poly (D,L-lactide-co-ε-caprolactone) for application in tendon/ligament tissue engineering / Wahida Abdul Rahman, Jean-Luc Six and Cécile Nouvel

In this research, copolymers of poly (D,L-lactide-co-ε-caprolactone) (PLCL) with 50:50 feed ratio were synthesized by the coordination-insertion ring opening polymerization (ROP) of cyclic esters at different temperature (130 0C, 150 0C and 200 0C). Both Sn(II)octoate (SnOct2) and isopropanol (iPrOH) were used as catalyst and initiator respectively and polymerization reaction were took part from 24 hours until 1 week. The conversion of monomer D,L-lactide and ε-caprolactone, polydispersity index (PDI) and total average molecular weight of copolymer PLCL can be determined by proton nuclear magnetic resonance (1H-NMR) and size exclusion chromatography coupled multi-angle laser light scattering (SEC-MALLS). Both analyses showed the increasing trend as the reaction temperature increased. The average sequence lengths of the lactidyl units (leLL) and caproyl (lecap) units, the degree of randomness (R) and the transesterification coefficients (TI and TII) were calculated from the 13C-NMR spectra. The average sequence lengths showed the decreasing trends, meanwhile there were small significant value increased for degree of randomness and transesterification coefficients when reaction temperature increased from 130 0C to 200 0C. The fabricated PLCL copolymers have a potential to be transformed into three dimensional scaffold for application in tendon/ligament tissue engineering

Global Soil Biodiversity Atlas

Soils provide numerous ecosystem services. Most people do not know that the key drivers of soil ecosystems are the living organisms within the soil. Soils may be home to over one fourth of all living species on Earth, with a significant part not yet characterized. The first Global Soil Biodiversity Atlas is a product of the Global Soil Biodiversity Initiative. It aims at raising awareness of the importance and beauty of soil biodiversity among the general public and policy makers. Furthermore, it highlights the need to increase efforts to develop a global assessment of soil biodiversity. Data on distribution of soil-dwelling organisms are often difficult to combine. The atlas represents an attempt to create a unique network among soil biodiversity scientists. Such an effort may help in reaching the level of attention that research on soil biodiversity deserves. With contributions from over 80 experts in soil biodiversity from all over the world, and over 170 pages, the atlas will also display distribution maps of the main soil organisms. Furthermore, an exceptionally high number of images will allow non-specialists to get in touch with this fascinating and mysterious world.JRC.D.6-Knowledge for Sustainable Development and Food Securit

Global maps of soil temperature

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km² resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e., offset) between in-situ soil temperature measurements, based on time series from over 1200 1-km² pixels (summarized from 8500 unique temperature sensors) across all the world’s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in-situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Global maps of soil temperature

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world\u27s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (−0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Global maps of soil temperature.

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Polymerization induced self-assembly: an opportunity toward the self-assembly of polysaccharide-containing copolymers into high-order morphologies

International audienc

Synthèse contrôlée et auto-organisation de glycopolymères amphiphiles à greffons polymères mésogènes, destinés à la vectorisation de principes actifs

De nouveaux glycopolymères greffés aux paramètres macromoléculaires contrôlés [dextrane-g-poly(acrylate de diéthylène glycol cholestéryle), Dex-g-PADEGChol] ont été préparés en quatre étapes via la stratégie de synthèse grafting from . L'originalité de ces glycopolymères réside dans la combinaison, et pour la première fois, d'une dorsale polysaccharide hydrophile biocompatible/ biodégradable et de greffons polymères hydrophobes à caractère mésogène. L'ATRP a été utilisée pour contrôler la croissance des greffons PADEGChol en milieu homogène à partir d'un macroamorceur dérivé de dextrane (DexAcBr). Les conditions de polymérisation avaient été préalablement ajustées en étudiant l'homopolymérisation du monomère ADEGChol en présence d'un amorceur modèle et de plusieurs systèmes catalytiques CuIBr/(PMDETA ou OPMI) dans différents solvants (THF ou toluène). Le caractère amphiphile de ces glycopolymères a été évalué et leurs propriétés mésomorphes ont été étudiées par calorimétrie différentielle à balayage, microscopie optique à lumière polarisante et par diffraction des rayons X. Des études préliminaires par microscope électronique à transmission et diffusion dynamique de la lumière polarisée ont démontré que ces glycopolymères adoptent une morphologie vésiculaire appelée polymersome en phase aqueuse, lorsque le DMSO est utilisé comme co-solvant. Ces nano-objets pourront être testés ultérieurement pour la formulation d'un nouveau type de vecteurs de principes actifsNew graft glycopolymers with well-defined parameters [dextran-g-poly(diethylene glycol cholesteryl ether acrylate) (Dex-g-PADEGChol)] have been prepared in four steps using the "grafting from" strategy. Challenge of this work arises from the combination for the first time of a hydrophilic, biocompatible/biodegradable polysaccharide backbone with mesogen hydrophobic polymeric grafts. Controlled growth of the grafts (PADEGChol) was obtained using ATRP initiated in homogeneous medium from a dextran derivative (DexAcBr). In order to find the best polymerization conditions, homopolymerization of ADEGChol monomer was investigated using an initiator model and various catalytic systems CuIBr/(PMDETA or OPMI) in two solvents (Toluene and THF). The amphiphilic properties of such glycopolymers were evaluated and their mesomorphic properties have been studied by thermal polarizing optical microscopy, differential scanning calorimetry and X-ray scattering. Using transmission electron microscopy and dynamic light scattering, vesicular morphology called "polymersome" was observed in aqueous medium when DMSO was used as co-solvent. These polymersomes could be tested as new drug delivery systemsMETZ-SCD (574632105) / SudocNANCY1-Bib. numérique (543959902) / SudocNANCY2-Bibliotheque electronique (543959901) / SudocNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

Elaboration de copolymères biorésorbables pour endoprothèse

L objectif de ce travail était d élaborer un copolymère biodégradable dans le but de développer une endoprothèse biorésorbable. Ainsi, des copolymères de lactide et de glycolide ont été synthétisés par copolymérisation par ouverture de cycle, dans des conditions permettant le contrôle de leurs paramètres macromoléculaires. Après plastification et mise en forme des copolymères par extrusion, l étude des propriétés mécaniques, à l état sec et après immersion en milieu aqueux, a été réalisée. Les essais de traction ont permis de vérifier l importance de la vitesse de sollicitation et d accéder à certaines grandeurs caractéristiques du matériau. L étude de la dégradation des copolymères, sous forme de jonc, a mis en évidence un mécanisme de dégradation hétérogène sur une durée en accord avec l application visée. La plastification par des molécules acides a permis d accélérer la vitesse d hydrolyse des copolymères. En conclusion, les propriétés mécaniques et de dégradation des copolymères PDLGA synthétisés sont donc en adéquation avec le cahier des charges de l application biomédicale.This work describes the synthesis of biodegradable copolymer to design a bioabsorbable endoprosthesis. Lactide and glycolide-based copolymers were synthesized by ring opening polymerization. Experimental conditions were chosen to produce controlled structures. The study of mechanical properties was performed in dry and wet states. During the tensile experiments, the effect of strain rate was noticed and some characteristics parameters were determined. Hydrolytic degradation of materials was fast and revealed a heterogeneous mechanism. Addition of acidic molecules for plasticizing increased the degradation rate of the copolymers.Mechanical properties and degradation of the PDLGA copolymers are indeed in good agreement with the specifications of this biomedical application.NANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF