Kinetic of polymers and nanoparticles adsorption on cellulose nanocrystal surfaces

International audienc

Joint estimation of balanced motions and internal tides from future wide-swath altimetry

Wide-swath altimetry, e.g. the Surface Water and Ocean Topography (SWOT) mission is expected to provide Sea Surface Height (SSH) measurements resolving scales of a few tens of kilometers. Over a large fraction of the globe, the SSH signal at these scales is essentially a superposition of a component due to balanced motions (BMs) and another component due to internal tides (ITs). Several oceanographic applications require the separation of these components and their mapping on regular grids. For that purpose, the paper introduces an alternating minimization algorithm that iteratively implements two data assimilation techniques, each specific to the mapping of one component: a quasi-geostrophic model with Back-and-Forth Nudging for BMs, and a linear shallow-water model with 4-Dimensional Variational (4DVar) assimilation for ITs. The algorithm is tested with Observation System Simulation Experiments (OSSE) where the truth is provided by a primitive-equation ocean model in an idealized configuration simulating a turbulent jet and mode-one ITs. The algorithm reconstructs almost 80% of the variance of BMs and ITs, the remaining 20% being mostly due to dynamics that cannot be described by the simple models used. Importantly, in addition to the reconstruction of stationary ITs, the amplitude and phase of nonstationary ITs are reconstructed. Sensitivity experiments show that the quality of reconstruction significantly depends upon the timing of observations. Although idealized, this study represents a step forward towards the disentanglement of BMs and ITs signals from real wide-swath altimetry data. Plain Language Summary Wide-swath altimetry, e.g. the Surface Water and Ocean Topography (SWOT) mission is expected to provide Sea Surface Height (SSH) images with pixels of 2 km, revealing motions at scales of a few tens of kilometers. At these scales, SSH variations are essentially due to the superposition of slow, balanced motions primarily constrain by Earth’s rotation, and fast, propagating motions due to internal waves mainly generated by interactions between bathymetry and tidal water displacements. Several oceanographic applications require the separation of these two SSH components and their mapping on regular grids. This paper presents an original method to achieve this separation, based on data assimilation approaches and simple dynamical models. Experiments with synthetic SSH images, simulated from an ocean circulation model with detailed physics, show the efficiency of the method

A molecular, morphological and cytological investigation of the identity of non-native Ludwigia (Onagraceae) populations in Britain

A combined molecular, morphological and cytological analysis was used to study the identity and number of species of Ludwigia section Oligospermum occurring in British waterways. Only one taxon was identified for which the name L. grandiflora subsp. hexapetala (Hook. & Arn.) G.L. Nesom & Kartesz is preferred. A chromosome count of 2n = 80 was made for all plants tested and DNA evidence demonstrates that at least two clones are present in Britain. Morphological characters to differentiate L.grandiflora subsp. hexapetala and L. peploides subsp. montevidensis (Spreng.) P.H. Raven are provided. Though the production of fruit in Britain by apparently isolated populations is noted, repeated introduction into the wild from gardens is judged to be primarily responsible for the British distribution of the taxon. Legislative implications are considered and an amendment to Schedule 9 of the UK Wildlife and Countryside Act (1981) is strongly advocated

Repetitive electrostatic pressurised intraperitoneal aerosol chemotherapy (ePIPAC) with oxaliplatin as a palliative monotherapy for isolated unresectable colorectal peritoneal metastases: protocol of a Dutch, multicentre, open-label, single-arm, phase II study (CRC-PIPAC)

Introduction: Repetitive electrostatic pressurised intraperitoneal aerosol chemotherapy with oxaliplatin (ePIPAC-OX) is offered as a palliative treatment option for patients with isolated unresectable colorectal peritoneal metastases (PM) in several centres worldwide. However, little is known about its feasibility, safety, tolerability, efficacy, costs and pharmacokinetics in this setting. This study aims to explore these parameters in patients with isolated unresectable colorectal PM who receive repetitive ePIPAC-OX as a palliative monotherapy. Methods and analysis: This multicentre, open-label, single-arm, phase II study is performed in two Dutch tertiary referral hospitals for the surgical treatment of colorectal PM. Eligible patients are adults who have histologically or cytologically proven isolated unresectable PM of a colorectal or appendiceal carcinoma, a good performance status, adequate organ functions and no symptoms of gastrointestinal obstruction. Instead of standard palliative treatment, enrolled patients receive laparoscopy-controlled ePIPAC-OX (92 mg/m 2 body surface area (BSA)) with intravenous leucovorin (20 mg/m 2 BSA) and bolus 5-fluorouracil (400 mg/m 2 BSA) every 6 weeks. Four weeks after each procedure, patients undergo clinical, radiological and biochemical evaluation. ePIPAC-OX is repeated until disease progression, after which standard palliative treatment is (re)considered. The primary outcome is the number of patients with major toxicity (grade ≥3 according to the Common Terminology Criteria for Adverse Events v4.0) up to 4 weeks after the last ePIPAC-OX. Secondary outcomes are the environmental safety of ePIPAC-OX, procedure-related characteristics, minor toxicity, postoperative complications, hospital stay, readmissions, quality of life, costs, pharmacokinetics of oxaliplatin, progression-free survival, overall survival, and the radiological, histopathological, cytological, biochemical and macroscopic tumour response. Ethics and dissemination: This study is approved by an ethics committee, the Dutch competent authority and the institutional review boards of both study centres. Results are intended for publication in peer-reviewed medical journals and for presentation to patients, healthcare professionals and other stakeholders

Mitochondrial, but not rDNA, genes fail to discriminate dinoflagellate species in the genus Ostreopsis

The marine dinoflagellate genus Ostreopsis includes species producing potent toxic compounds, such as paliytoxin and palytoxin analogs, which might cause problematic blooms in the Mediterranean Sea and other tropical or temperate areas. Phylogenetic and phylogeographical studies based on sequences of ribosomal genes, revealed the existence of distinct species and, within them, clades in relation to geographical distribution potentially representing new or cryptic species. The morphological variability of Ostreopsis complicates the identification of species; thus, molecular analyses of isolates or field samples can be helpful. The aim of this study was to improve the characterization of Ostreopsis species and investigate the geographical distribution by using large dataset composed of both new and old sampled isolates. To determine if mitochondrial genes can be used to identify Ostreopsis species, we designed new primers sets then amplified and sequenced representative regions of the COI (cytochrome c oxydase 1) and cob (cytochrome b) genes. Phylogenetic analyses of the resulting mitochondrial DNA (mtDNA) and existing or new ribosomal DNA (rDNA) sequence data showed little divergence in the mtDNA sequences among Ostreopsis species indicating that neither the COI or cob genes are phylogenetically informative. In contrast, the ribosomal gene phylogeny indicated the existence of distinct Ostreopsis species. A network of haplotypes (based on ITS-5.8S rDNA) inferred from O. cf. ovata isolates collected worldwide revealed that Atlantic/Mediterranean and Indo/Pacific areas might host two separated large populations. In conclusion, it appears that rDNA gene sequences provide an effective molecular means of distinguishing the phylogenetic and phylogeographical relationships among Ostreopsis species.Versión del editor3,083