Effect of alkali halides on α-chymotrypsin activity in the plastein reaction

The influence of different alkali halides (LiF, LiCl. LiBr, NaF, NaCl, NaBr, KF, KCl and KBr) on α-chymotrypsin-catalysed plastein synthesis has been studied in aqueous medium at different substrate concentrations. The results showed an enhancing effect on the plastein synthesis enzyme action by the presence of salts, proportional to salt concentration, which was decreased when the substrate concentration was increased. Additionally, these facts allowed the ions to be classified as a function of their activation power (F^? > Cl^? > Br^?: K⁺ > Na⁺ > Li⁺), which was in agreement with the interpretation of the Hofmeister lyotropic series. The influence of the several phenomena produced by the presence of salts in the plastein reaction, such as, salt-substrate interactions and water activity, as well as the presence of deactivated enzyme was also analysed. The obtained results showed that the substrate concentration is the most important factor, and the activating effect of salts could be simultaneously involved with both a structural change on the substrate conformation and a reduction of water activity into the reaction media, enhancing the catalytic capability of the α-chymotrypsin towards a peptide synthesis action.     

Modeling and verification of a telecommunication application using live sequence charts and the Play-Engine tool

We apply the scenario-based approach to modeling, via the language of live sequence charts (LSCs) and the Play-Engine tool to a real-world complex telecommunication service, . It allows a user to call for help from a doctor, the fire brigade, a car maintenance service, etc. These kinds of services are built on top of an embedded platform, using both new and existing service components, and their complexity stems from their distributed architecture, the various time constraints they entail, and their rapidly evolving underlying systems. A well known problem in this class of telecommunication applications is that of feature interaction, whereby a new feature might cause problems in the execution of existing features. Our approach provides a methodology for high-level modeling of telecommunication applications that can help in detecting feature interaction at early development stages. We exhibit the results of applying the methodology to the specification, animation and formal verification of the Depannage service.

Functionalized Cluster‐Assembled Magnetic Nanostructures for Applications to high Integration‐Density Devices

This paper presents recent results on the preparation and characterization of original magnetic nanostructures from nanoclusters preformed in the gas phase. Magnetic binary‐clusters (i.e. Co‐Sm, Co‐Pt, Co‐Ag) with rather well controlled sizes, structures and compositions, are prepared in the gas phase using a combined laser vaporization‐rare gas condensation source and subsequently deposited at low energy (LECBD : Low Energy Cluster Beam Deposition) on various functionalized substrates to grow cluster‐assembled magnetic nanostructures exhibiting specific magnetic properties. Especially a high magnetic anisotropy and consequently a high magnetic blocking temperature compatible with future applications to high density memory devices and spin electronics are expected. In this context of applications, 2D‐organized arrays of functionalized binary‐cluster assembled dots are prepared by LECBD on FIB‐functionalized substrates (FIB: Focussed Ion Beam) with the ultimate objective to reach areal densities in the range of the Tbits/in².     

An interleaved sampling scheme for the characterization of single qubit dynamics

In this paper, we demonstrate that interleaved sampling techniques can be used to characterize the Hamiltonian of a qubit and its environmental decoherence rate. The technique offers a significant advantage in terms of the number of measurements that are required to characterize a qubit. When compared to the standard Nyquist?CShannon sampling rate, the saving in the total measurement time for the interleaved method is approximately proportional to the ratio of the sample rates.     

Surface enrichment of biomimetic apatites with biologically-active ions Mg2+ and Sr2+: A preamble to the activation of bone repair materials

The surface activation of calcium phosphate-based biomaterials for bone repair is an emerging route for improving bone regeneration processes. One way for such activation is through the exchange of surface calcium ions with biologically-active cations such as Mg²⁺ or Sr²⁺. In this work, the interactions of non-carbonated and carbonated nanocrystalline apatites with Mg²⁺ and Sr²⁺ were investigated by means of ion exchange experiments in solution. Langmuir-type isotherms were determined. For both Sr and Mg, a greater uptake was observed on the carbonated sample, and on both types of apatites the maximum strontium uptake was greater than that of magnesium. Inverse exchanges showed that the proportion of reversibly fixed ions after surface exchange was close to 85% for Mg and 75–80% for Sr. The results are related to the presence of a surface hydrated layer on the nanocrystals and possible exchange mechanisms are discussed. Our results favor the hypothesis of hetero-ionic surface exchanges (Mg²⁺↔Ca²⁺, Sr²⁺↔Ca²⁺) within the hydrated layer, and some analogy with octacalcium phosphate (OCP) is considered. This work should prove helpful for the control and understanding of the activation of synthetic apatite-based powders or scaffolds with bioactive elements, as well as for the global understanding of biomineralization processes.     

Starch and oil in the donor cow diet and starch in substrate differently affect the in vitro ruminal biohydrogenation of linoleic and linolenic acids

Trans isomers of fatty acids exhibit different health properties. Among them, trans-10,cis-12 conjugated linoleic acid has negative effects on milk fat production and can affect human health. A shift from the trans-11 to the trans-10 pathway of biohydrogenation (BH) can occur in the rumen of dairy cows receiving high-concentrate diets, especially when the diet is supplemented with highly unsaturated fat sources. The differences of BH patterns between linoleic acid (LeA) and linolenic acid (LnA) in such ruminal conditions remain unknown; thus, the aim of this work was to investigate in vitro the effects of starch and sunflower oil in the diet of the donor cows and starch level in the incubates on the BH patterns and efficiencies of LeA and LnA. The design was a 4 × 4 Latin square design with 4 cows, 4 periods, and 4 diets with combinations of 21 or 34% starch and 0 or 5% sunflower oil. The rumen content of each cow during each period was incubated with 4 substrates, combining 2 starch levels and either LeA or LnA addition. Capillary electrophoresis single-strand conformation polymorphism of incubates showed that dietary starch decreased the diversity of the bacterial community and the high-starch plus oil diet modified its structure. High-starch diets poorly affected isomerization and first reduction of LeA and LnA, but decreased the efficiencies of trans-11,cis-15-C18:2 and trans C18:1 reduction. Dietary sunflower oil increased the efficiency of LeA isomerization but decreased the efficiency of trans C18:1 reduction. An interaction between dietary starch and dietary oil resulted in the highest trans-10 isomers production in incubates when the donor cow received the high-starch plus oil diet. The partition between trans-10 and trans-11 isomers was also affected by an interaction between starch level and the fatty acid added to the incubates, showing that the trans-10 shift only occurred with LeA, whereas LnA was mainly hydrogenated via the more usual trans-11 pathway, whatever the starch level in the substrate, although the bacterial communities were not different between LeA and LnA incubates. In LeA incubates, trans-10 isomer production was significantly related to the structure of the bacterial community.     

Effect of cooking temperature and cooking time on Warner-Bratzler tenderness measurement and collagen content in rabbit meat

The effects of cooking temperature (50-90?°C) and time (10-120 min) on Warner-Bratzler (WB) tenderness measurement of longissimus lumborum (LL) muscle in 70-day-old rabbits were investigated. Cooking losses, total collagen content and collagen solubility of LL muscle were measured in parallel. Increasing cooking temperature caused a four-phase effect on WB measurement. Stress and total energy were significantly increased between raw meat and cooked meat at 50?°C, then they dramatically decreased to a minimum observed at 60-65?°C, and increased again to reach a maximum at 80-90?°C. Cooking losses exhibited an 83% increase between 50 and 80?°C. At 80?°C, stress and total energy values remained constant after 20 and 40 min respectively. LL muscle collagen content was 16.4±2.3 mg/g of dried muscle. Collagen solubility at 77?°C for 1 h was high: 75.3±8.1%.     

Endocellular pathogenic bacteria in the monogenean Euzetrema knoepffleri

Intracellular bacteria (Rickettsia) are found in the Monogenean Euzetrema knoepffleri, vesicular endoparasite of the Amphibian Euproctus montanus (Urodela). In some conditions, they cause cytoplasmic damage in the host tissues, which demonstrates their pathogenicity. These bacteria are present during all the stages of the life-cycle of E. knoepffleri. Their transmission from one generation to the next occurs through the gametes.     

Oxoacidity and its influence on electrochemical properties of molten tin(II) chloride

The electrochemical properties of molten tin(II) chloride depend on oxoacidity and the corresponding E^°′/pO^2? diagram at 523 K is given. The latter was obtained by coupling voltammetric and potentiometric results with thermochemical data at the same temperature. Consequently, behaviour of electrochemical cells involving this melt is explained.     

Diffraction by lossy dielectric wedges using both heuristic UTDformulations and FDTD

An improvement of the uniform theory of diffraction (UTD) coefficient for the case of a lossy dielectric wedge when a transmitted ray exists is presented. We elaborated two new terms that are added to the classical UTD diffraction coefficient, so that we obtain continuity of the total field. This new UTD formulation is compared to a numerical method based on finite difference time domain (FDTD). We outline the adaptation of the FDTD grid calculation, which was necessary to isolate only one edge diffraction and to treat two-dimensional (2-D) structures with two infinite sides. This comparison allows one to conclude that the new diffraction coefficient is relevant for the case of a lossy dielectric wedge. Then we present a comparison between two different versions of the UTD diffraction coefficient based on single or multiple reflection in the case of a dielectric slab. Thus, we can conclude to the significance of the multipaths for modeling dielectric structures. Finally, we analyze the results obtained with two consecutive wedge vertices in order to show that the slope diffraction related to the doubly diffracted field allows one to predict the field behind the structure when the transmitted field does not exist