Biodegradable hollow fibres for the controlled release of drugs

Biodegradable hollow fibres of poly-l-lactic acid (PLLA) filled with a suspension of the contraceptive hormone levonorgestrel in castor oil were implanted subcutaneously in rats to study the rate of drug release, rate of biodegradation and tissue reaction caused by the implant. The in vivo drug release was compared with the release in vitro using different release media. Fibres, disinfected with alcohol showed a zero-order release, both in vitro and in vivo, for over 6 months. Fibres, either γ-sterilized or disinfected with alcohol were harvested at time intervals ranging from 1 d to 6 months after implantation. Molecular weights of PLLA, tensile strengths, and remaining amounts of drug were determined as a function of time.\ud \ud The tissue reaction can be described as a very moderate foreign body reaction with the initial presence of macrophages, which are gradually replaced by fibroblasts which form a collagen capsule. Molecular weight determinations of PLLA showed a decrease from an initial Mw of 1.59x10 5 to 5.5 × 10 4 in 4 months (after alcohol sterilization). A gradual decrease in fibre strength with time was observed which did not significantly impair the release rate of levonorgestrel

Environnement intérieur : vers une prise de conscience française de l'enjeu sanitaire

National audienceLargement prise en compte depuis une vingtaine d'années aux Etats-Unis, au Canada et dans les pays nord-européens, la problématique de l'environnement intérieur semble émerger concrètement en France

Preservation of the Cell-Biomaterial Interface at the Ultrastructural Level

Studying the tissue-biomaterial interface at the ultrastructural level is not without problems. Dissolution of the biomaterial in one of the dehydration or embedding media causes holes and shatter during sectioning or dislodgement of the biomaterial. The fine tuning of the hardness of both biomaterial and embedding medium, as well as the introduction of butyl-2,3- epoxypropylether as an intermediate between the dehydration series and the Epon resin , improving the impregnation , will solve many of the problems mentioned. With this improved technique good results were obtained with materials ranging from teflon, poly(Lactic acid) and polyurethanes to tissue culture polystyrene. No holes, shatter or dislodgement of the biomaterial was observed

Non-orthogonal configuration interaction with single substitutions for core-excited states: An extension to doublet radicals

In this paper, we present an open-shell extension of the non-orthogonal configuration interaction singles (NOCIS) method for the calculation of core-excited states, intended for peak assignment in XAS spectra of doublet radicals. This extension requires the consideration of additional configurations due to the singly occupied open-shell orbital, and the addition of essential orbital relaxation effects is found to provide a significant improvement on standard CIS, while maintaining the desirable properties of spin purity, variationality, and size consistency. We apply this method to the calculation of core excitations for several open-shell molecules and demonstrate that it performs competitively with other available methods, despite a lack of dynamic correlation. In particular, relative to CVS-ADC(2)-x, RMS error is reduced by a factor of 6 over usual orthogonal CIS and is comparable to time-dependent density functional theory with the best short-range corrected functionals

The Phoenix Deep Survey: The 1.4 GHz microJansky catalogue

The initial Phoenix Deep Survey (PDS) observations with the Australia Telescope Compact Array have been supplemented by additional 1.4 GHz observations over the past few years. Here we present details of the construction of a new mosaic image covering an area of 4.56 square degrees, an investigation of the reliability of the source measurements, and the 1.4 GHz source counts for the compiled radio catalogue. The mosaic achieves a 1-sigma rms noise of 12 microJy at its most sensitive, and a homogeneous radio-selected catalogue of over 2000 sources reaching flux densities as faint as 60 microJy has been compiled. The source parameter measurements are found to be consistent with the expected uncertainties from the image noise levels and the Gaussian source fitting procedure. A radio-selected sample avoids the complications of obscuration associated with optically-selected samples, and by utilising complementary PDS observations including multicolour optical, near-infrared and spectroscopic data, this radio catalogue will be used in a detailed investigation of the evolution in star-formation spanning the redshift range 0 < z < 1. The homogeneity of the catalogue ensures a consistent picture of galaxy evolution can be developed over the full cosmologically significant redshift range of interest. The 1.4 GHz mosaic image and the source catalogue are available on the web at http://www.atnf.csiro.au/~ahopkins/phoenix/ or from the authors by request.Comment: 16 pages, 11 figures, 4 tables. Accepted for publication by A

Op weg naar een duurzaam elzensingellandschap

Veel elzensingels zijn verdwenen of sterk in kwaliteit achteruit gegaan. De instandhouding van dit type landschap is tegenwoordig enkel mogelijk met behulp van vrijwilligers voor landschapsbeheer en subsidies van de overheid. Alterra heeft met een groep betrokkenen als Staatsbosbeheer, Landschapsbeheer Friesland, LNV Noord, Stichting Boslandbouw bekeken, hoe dit landschap duurzaam ontwikkeld kan worde

Provenance and production: casks in the Dutch archaeological context

The Late Medieval and Early Modern periods in the Netherlands are marked by an upsurge in the production, use and repurposing of casks in cities. This is inextricably linked with the growing marine and riverine trade markets and the increase in artisan production. Casks have been found on shipwrecks, where they were used as containers for merchandise (primary purpose) and in urban areas, where they were repurposed as shafts for wells or cesspits (secondary purpose). As a result, the initial production phase of the lifecycle of casks often remained undetected. This study aims to generate an overview of the dendrochronological studies conducted in the past decades by Dutch dendrochronologists on casks from Dutch archaeological context, in which the felling year of the wood used to construct the casks can be dated from the 12th to 18th centuries, to gain insight into their production by coopers. The first objective is to better understand the diverse provenance areas detected in the coopers’ timber, after which the diachronic developments in the use of the timber from specific provenance areas can be addressed. The main objective is to assess whether it is possible to distinguish locally produced casks from casks used to import merchandise, which was successful in some cases. In addition to the dendrochronological and archaeological data, archival sources were used to contextualize and substantiate the analyses and interpretations.NWORoman Provinces, Middle Ages and Modern Perio