Biopharmaceutical Assessment of Dexamethasone Acetate-Based Hydrogels Combining Hydroxypropyl Cyclodextrins and Polysaccharides for Ocular Delivery

We previously developed two optimized formulations of dexamethasone acetate (DXMa) hydrogels by means of special cubic mixture designs for topical ocular administration. These gels were elaborated with hydroxypropyl-β-CD (HPβCD) and hydroxypropyl-γ-CD (HPγCD) and commercial hydrogels in order to enhance DXMa water solubility and finally DXMa’s ocular bioavailability and transcorneal penetration. The main objective of this study was to characterize them and to evaluate in vitro, ex vivo, and in vivo their safety, biopermanence, and transcorneal permeation. Gels A and B are Newtonian fluids and display a viscosity of 13.2 mPa.s and 18.6 mPa.s, respectively, which increases their ocular retention, according to the in vivo biopermanence study by PET/CT. These hydrogels could act as corneal absorption promoters as they allow a higher transcorneal permeation of DXMa through porcine excised cornea, compared to DEXAFREE® and MAXIDEX®. Cytotoxicity assays showed no cytotoxic effects on human primary corneal epithelial cells (HCE). Furthermore, Gel B is clearly safe for the eye, but the effect of Gel A on the human eye cannot be predicted. Both gels were also stable 12 months at 25 °C after sterilization by filtration. These results demonstrate that the developed formulations present a high potential for the topical ocular administration of dexamethasone acetateThis work was supported by Labex ARCANE (ANR-11-LABX-0003-01) and Institut de Chimie Moléculaire de Grenoble (FR 2607) and the Glyco@Alps program (ANR-15-IDEX-02). A.F.-F. acknowledges the support obtained from the Instituto de Salud Carlos III (ISCIII) through its research grants (JR18/00014). X.G.-O. acknowledges the financial support of the IDIS (Health Research Institute of Santiago de Compostela) (predoctoral research fellowships)S

Wavelet Analysis for Wind Fields Estimation

Wind field analysis from synthetic aperture radar images allows the estimation of wind direction and speed based on image descriptors. In this paper, we propose a framework to automate wind direction retrieval based on wavelet decomposition associated with spectral processing. We extend existing undecimated wavelet transform approaches, by including à trous with B3 spline scaling function, in addition to other wavelet bases as Gabor and Mexican-hat. The purpose is to extract more reliable directional information, when wind speed values range from 5 to 10 ms−1. Using C-band empirical models, associated with the estimated directional information, we calculate local wind speed values and compare our results with QuikSCAT scatterometer data. The proposed approach has potential application in the evaluation of oil spills and wind farms

Self-assembled biotransesterified cyclodextrins as potential Artemisinin nanocarriers. II: In vitro behavior toward the immune system and in vivo biodistribution assessment of unloaded nanoparticles.

In a previous study, we reported on the formulation of Artemisinin-loaded surface-decorated nanoparticles (nanospheres and nanoreservoirs) by co-nanoprecipitation of PEG derivatives (PEG1500 and PEG4000-stearate, polysorbate 80) and biosynthesized γ-CD fatty esters. In the present study, the co-nanoprecipitation was extended to the use of a PEGylated phospholipid, namely DMPE-PEG2000. As our goal was to prepare long-circulating nanocarriers for further systemic delivery of Artemisinin (ART), here, we have investigated, on the one hand, the in vitro behavior of these surface-modified γ-CD-C10 particles toward the immune system (complement activation and macrophage uptake assays) and, on the other hand, their biodistribution features in mice. These experiments showed that the in vitro plasma protein adsorption and phagocytosis by macrophage cells triggered by γ-CD-C10 nanoparticles were significantly reduced when their surface was decorated with amphiphilic PEGylated molecules, in particular PEG1500-stearate, DMPE-mPEG2000 or polysorbate 80. The prolonged blood circulation time assessed by fluorescence imaging was demonstrated for unloaded γ-CD-C10-based nanospheres and nanoreservoir particles containing DMPE-PEG2000 and polysorbate80, respectively. These nanoparticles also proved to be non-hemolytic at the concentration range used in vivo. Within the limits of the conducted experiments, the co-nanoprecipitation technique may be considered as an alternative for surface modification of amphiphilic CD-based drug delivery systems and may be applied to the systemic delivery of ART

Methods and tools to evaluate the availability of renewable energy sources

The recent statements of both the European Union and the US Presidency pushed in the direction of using renewable forms of energy, in order to act against climate changes induced by the growing concentration of carbon dioxide in the atmosphere. In this paper, a survey regarding methods and tools presently available to determine potential and exploitable energy in the most important renewable sectors (i.e., solar, wind, wave, biomass and geothermal energy) is presented. Moreover, challenges for each renewable resource are highlighted as well as the available tools that can help in evaluating the use of a mix of different sources

Réduction de l'aptitude au feutrage des fibres de laine par traitements oxydatifs et protéolytique de surface

Le retrecissement des etoffes de laine est un phenomene le plus souvent indesirable qui limite l'utilisation de cette fibre dans le secteur textile. Dans 90% des cas, le procede industriel permettant de lutter contre ce phenomene est realise par un traitement a base de chlore et de derive chlore tres polluant. Dans ce contexte, l'utilisation d'enzymes proteolytiques sur une fibre essentiellement de nature proteique est apparue realisable et ecologique. Cependant, la structure responsable du retrecissement est fortement stabilisee par des ponts disulfures qui interdisent l'attaque directe des proteases sur les fibres sans pre-traitement d'oxydation. Apres verification de l'efficacite d'un traitement d'oxydation au chlore suivi de l'hydrolyse enzymatique des fibres, une etape prospective a ete entreprise pour remplacer le chlore par un agent plus neutre sur le plan environnemental. Ainsi, deux traitements ont finalement ete retenus et optimises par la methode des plans d'experiences. Dans le cas de l'oxydation par l'acide performique suivie de l'hydrolyse enzymatique par les subtilisines, un plan d'experiences factoriel a permis de diminuer fortement l'aptitude des fibres au feutrage. Toutefois, l'abaissement de la tenacite des fibres traitees a egalement ete constate sans qu'aucune amelioration satisfaisante n'ait ete apportee par la methode d'optimisation du simplex.L'optimisation d'un deuxieme traitement oxydatif par l'ozone et hydrolyse enzymatique a ete realisee par un plan factoriel complet 2 4 complete par un plan composite centre. A l'issue de cette etude, nous avons demontre que ce procede permet d'eliminer toute forme de feutrage, ameliore les caracteristiques colorimetriques et diminue favorablement le diametre moyen des fibres sans en alterer la tenacite. Une chute importante du taux de 18-methyleicosanoate present au niveau de la cuticule a egalement ete mesuree finalement, un test norme de lavage en machine conclut cette etude en confirmant le caractere irretrecissable des fibres oxydees par l'ozone et attaquees par les subtilisines.LILLE1-BU (590092102) / SudocSudocFranceF

Règles d'accroissement des cristaux, en présence de substance tensio˗actives

Barillet Francis, Choisnard A. Règles d'accroissement des cristaux, en présence de substance tensio˗actives. In: Bulletin de la Société française de Minéralogie, volume 61, 7-8, 1938. pp. 297-303

Développement des techniques spatiales de cartographie du potentiel éolien offshore et côtier par imagerie radarsat : cas du golfe du St-Laurent

This paper document the usefulness of offshore and coastal wind maps from satellite techniques. As a step before metering programs, remote sensing approaches are gaining much interest, especially for offshore analysis. As an intermediate approach, it gives first estimates of the best wind sites. In the complex coastal area of St-Lawrence gulf, strong effects of local topography characterize wind fields and the wind resource assessment is challenging. Wind fields are extracted from Synthetic Aperture Radar (SAR) scenes provided by the RADARSAT-1 satellite and from QuickSCAT scatterometer collocated wind direction. The spatial resolution of such a technique is around 400 m covering wide region until 300 by 300 km. Among interesting findings, it appears that a relative small sample of scenes can already indicates the best spots to investigate for further analysis. Accuracy of the method is evaluated at 1.5 m/s offshore and around 2 m/s close to the shore

Sediment solid phase characteristics on the Amazon shelf obtained in April/May 2021 during RV METEOR cruise M174

The Amazon River is known as a region of intense biochemical reactivity. As a result of increased anthropogenic impacts in its catchment (e.g. population growth, agriculture, and deforestation), The Amazon River is undergoing fundamental changes. The RV METEOR cruise M174 (https://doi.org/10.1594/PANGAEA.935041) aimed to provide an integrated overview of nitrogen cycling processes in areas influenced by the Amazon River, which is crucial to estimate the ecosystem's health and productivity. During this cruise, a MUC was deployed at eight stations to collect short sediment cores, in order to explore the influence of the river on sediments. This dataset presents the results of sediment solid phase characteristics from the surface sediment down to 30 cm depth

Garuda: A lightweight tweet collector tool

International audienceSocial network data are used in a wide range of domains of interest, including politics, marketing or social sciences. Among existing social networks, Twitter appears as a major platform for researchers, as its data are available through API accessible to any Twitter user that requests a developer account. However, for users without information technology skills, it can be difficult to set up a collect and retrieve expected tweets. To this end, we propose Garuda, a lightweight tweet collector tool, allowing to efficiently set up a collect and to transform tweets in a more usable format