Secure biometric authentication with improved accuracy

We propose a new hybrid protocol for cryptographically secure biometric authentication. The main advantages of the proposed protocol over previous solutions can be summarised as follows: (1) potential for much better accuracy using different types of biometric signals, including behavioural ones; and (2) improved user privacy, since user identities are not transmitted at any point in the protocol execution. The new protocol takes advantage of state-of-the-art identification classifiers, which provide not only better accuracy, but also the possibility to perform authentication without knowing who the user claims to be. Cryptographic security is based on the Paillier public key encryption scheme

Free-standing polyelectrolyte membranes made of chitosan and alginate

Free-standing films have increasing applications in the biomedical field as drug delivery systems for wound healing and tissue engineering. Here, we prepared free-standing membranes by the layer-by-layer assembly of chitosan and alginate, two widely used biomaterials. Our aim was to produce a thick membrane and to study the permeation of model drugs and the adhesion of muscle cells. We first defined the optimal growth conditions in terms of pH and alginate concentration. The membranes could be easily detached from polystyrene or polypropylene substrate without any postprocessing step. The dry thickness was varied over a large range from 4 to 35 μm. A 2-fold swelling was observed by confocal microscopy when they were immersed in PBS. In addition, we quantified the permeation of model drugs (fluorescent dextrans) through the free-standing membrane, which depended on the dextran molecular weight. Finally, we showed that myoblast cells exhibited a preferential adhesion on the alginate-ending membrane as compared to the chitosan-ending membrane or to the substrate side.This work was financially supported by Foundation for Science and Technology (FCT) through the Scholarship SFRH/BD/64601/2009 granted to S.G.C. C.M. is indebted to Grenoble INP for financial support via a postdoctoral fellowship. This work was supported by the European Commission (FP7 Program) via a European Research Council starting grant (BIOMIM, GA 259370 to C.P.). C.P. is also grateful to Institut Universitaire de France and to Grenoble Institute of Technology for financial support. We thank Isabelle Paintrand for her technical help with the confocal apparatus and Patrick Chaudouet for his help with SEM imaging

Analysis of the seasonal variation in biochemical composition of

The biochemical composition of Daphnia magna Straus, the dominant planktonic crustacean of the waste stabilisation pond of Differdange (Grand-Duchy of Luxembourg), was quantitatively determined from October 1993 to July 1994. Over the sampling period, the average composition (mean ± S.D.) was 271 ± 64 mg proteins.g-1 dry weight (DW), 100 ± 28 mg lipids.g-1 (DW), 96 ± 58 μg carotenoids.g-1 (DW), 49 ± 14 mg chitin.g-1 (DW) and 125 ± 78 mg ash.g-1 (DW). The seasonal variations of the biochemical composition were related to several ecological variables (water temperature, dissolved oxygen concentration, pH, water transparency, chlorophyll a concentration and D. magna biomass). The chitin content was positively correlated to the water temperature as a result of the strong influence of this later variable on the moulting rate of the daphnids and, subsequently, on the chitin synthesis by these organisms. The carotenoid content was positively correlated to the water transparency as a result of their photoprotective role in daphnids. The fluctuations of the lipid, protein and ash levels in D. magna depended to the food availability. Despite a seasonal variation in the biochemical composition, D. magna appeared to have adequate lipid and protein levels to be used in aquaculture. Its carotenoid content is similar to fish meals used to color salmonid flesh and these organisms could be used for this purpose. The prospect of using D. magna for chitin extraction is worth considering with respect to its significant chitin content, especially if highly valuable applications are aimed