Cellefrouin – La fontaine Saint-Martin

Située à l’est de la chapelle Saint-Martin de Cellefrouin, dans un des prés entre le chemin vicinal et la rivière, appelés « Prés de l’abbaye ou des moines » sur le cadastre ancien, la fontaine est sur une parcelle appartenant à la mairie de Cellefrouin. Oubliée de tous, elle a été arasée accidentellement en 2008. Il s’agit d’une petite construction de pierres sèches, de 2,02 m de long sur 1,90 m de large en dimensions extérieures, pour une ouverture trapézoïdale de 0,5 m de long sur 0,59 m d..

Controlled release properties and final macroporosity of a pectin microspheres–calcium phosphate composite bone cement

The use of calcium phosphate cements (CPC) is restricted by their lack of macroporosity and poor drug release properties. To overcome these two limitations, incorporating degradable polymer microparticles into CPC is an attractive option, as polymer microparticles could help to control drug release and induce macroporosity after degradation. Although few authors have yet tested synthetic polymers, the potentiality of polysaccharides’ assuming this role has never been explored. Low-methoxy amidated pectins (LMAP) constitute valuable candidates because of their biocompatibility and ionic and pH sensitivity. In this study, the potentiality of a LMAP with a degree of esterification (DE) of 30 and a degree of amidation (DA) of 19 was explored. The aim of this study was to explore the influence of LMAP microspheres within the composite on the cement properties, drug release ability and final macroporosity after microspheres degradation. Three LMAP incorporation ratios, 2%, 4% and 6% w/w were tested, and ibuprofen was chosen as the model drug. In comparison with the CPC reference, the resulting composites presented reduced setting times and lowered the mechanical properties, which remained acceptable for an implantation in moderate-stress-bearing locations. Sustained release of ibuprofen was obtained on at least 45 days, and release rates were found to be controlled by the LMAP ratio, which modulated drug diffusion. After 4 months of degradation study, the resulting CPC appeared macroporous, with a maximum macroporosity of nearly 30% for the highest LMAP incorporation ratio, and interconnectivity between pores could be observed. In conclusion, LMAP appear as interesting candidates to generate macroporous bone cements with tailored release properties and macroporosity by adjusting the pectin content within the composites

Biomimetic nanocrystalline apatites: Emerging perspectives in cancer diagnosis and treatment

Nanocrystalline calcium phosphate apatites constitute the mineral part of hard tissues, and the synthesis of biomimetic analogs is now wellmastered at the labscale. Recent advances in the fine physicochemical characterization of these phases enable one to envision original applications in the medical field along with a better understanding of the underlying chemistry and related pharmacological features. In this contribution, we specifically focused on applications of biomimetic apatites in the field of cancer diagnosis or treatment. We first report on the production and first biological evaluations (cytotoxicity, proinflammatory potential, internalization by ZR751 breast cancer cells) of individualized luminescent nanoparticles based on Eudoped apatites, eventually associated with folic acid, for medical imaging purposes. We then detail, in a first approach, the preparation of tridimensional constructs associating nanocrystalline apatite aqueous gels and drugloaded pectin microspheres. Sustained releases of a fluorescein analog (erythrosin) used as model molecule were obtained over 7 days, in comparison with the ceramic or microsphere reference compounds. Such systems could constitute original bonefilling materials for in situ delivery of anticancer drug

“Fracture” phenomena in shearing flow of viscous liquids

In start-up of steady shearing flow of two viscous unentangled liquids, namely low-molecular-weight polystyrene and α-D-glucose, the shear stress catastrophically collapses if the shear rate is raised above a value corresponding to a critical initial shear stress of around 0.1–0.3 MPa. The time dependence of the shear stress during this process is similar for the two liquids, but visualization of samples in situ and after quenching reveals significant differences. For α-D-glucose, the stress collapse evidently results from debonding of the sample from the rheometer tool, while in polystyrene, bubbles open up within the sample, as occurs in cavitation. Some similarities are pointed out between these phenomena and that of “lubrication failure” reported in the tribology literature.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47212/1/397_2004_Article_BF00368135.pd

Cellefrouin (Charente). Fontaine Saint-Martin, église prieurale Saint-Martin de Cellefrouin

Cellefrouin est un bourg de Charente limousine, aux confins NE de l’ancien Angoumois médiéval. Connu pour son actuelle église Saint-Nicolas, à l’origine ancienne collégiale Saint-Pierre et centre d’une abbaye augustine de la fin du xie et du début du xiie s., Cellefrouin comptait plusieurs autres édifices religieux, dont les ruines, sur un terrain privé, de la chapelle Saint-Martin, méconnues, sur la rive droite du Son, près de la fontaine Saint-Martin. Il ne subsistait qu’une travée avec deu..