Diamond nanoseeding on silicon: Stability under H2 MPCVD exposures and early stages of growth

Detonation nanodiamond dispersed on silicon surfaces underwent different H₂ MPCVD exposures. The induced changes at the surface have been characterized in situ by XPS and XEELS. Then, a short CH₄/H₂ growth step was applied. This sequential study revealed an excellent stability of detonation nanodiamond. The sp³ etching rate is insufficient to remove nanodiamond even under intense H₂ plasma. The H₂ exposure could be successfully used to remove C–C sp² carbon without altering sp³ seeds. Moreover, the formation of silicon carbide observed after the hydrogen treatment is thought to be helpful to enhance the adhesion of nanodiamond particles on the substrate.     

Some Results on FCSR Automata With Applications to the Security of FCSR-Based Pseudorandom Generators

This article describes new theoretical results concerning the general behavior of a feedback with carry shift register (FCSR) automaton. They help to better understand how the initial parameters must be chosen to use this automaton as a basic block of a filtered stream cipher. These results especially concern the structure of the transition graph of an FCSR automaton and the number of iterations of the FCSR transition function required to reach the main part of the graph. A potential linear weakness and a easy way to prevent the corresponding attack are also given.     

Relaxation mechanisms and microstructure in glass and glass-ceramics

Two LAS (Li₂O–Al₂O₃–SiO₂)-type glass-ceramics and their parent glass have been studied by isothermal mechanical spectroscopy. These materials have the same chemical composition but the two glass-ceramics differ in microstructure: one is a ‘β-quartz’ glass-ceramic whereas the other one is of ‘β-spodumene’ type. The isothermal internal friction measurements performed in a frequency sweep [10⁻⁴–31.6 Hz] with an inverted torsion pendulum, submitted to subresonant forced oscillations, at temperatures between 93 and 820 K, have revealed several mechanical relaxation peaks. A single internal friction peak is observed in the glass sample whereas two peaks occur in the ‘β-quartz’ and ‘β-spodumene’ glass-ceramics. A detailed microstructure analysis (XRD, IRTF, SEM, TEM and DTA) and dielectric loss measurements have allowed to interpret these relaxation phenomena. The mechanical relaxation peak observed in the glass (290 K for 1 Hz) is assigned to the stress-induced movement of lithium ions. In each glass-ceramic the ‘low-temperature’ peak (340 K for 1 Hz) is linked with the ion mobility in the respective main crystalline phase. As for the ‘high-temperature’ peak, its origin is totally different for the two glass-ceramics; in the ‘β-quartz’ glass-ceramic it is due to the Mg²⁺ and Zn²⁺ ion relaxation in the crystalline phase, whereas in the ‘β-spodumene’ glass-ceramic it is linked with a complex entity within the residual vitreous phase.     

Real time investigation of diamond nucleation by laser scattering

Diamond nucleation onto diamond-free substrates remains a major challenge for most diamond films applications. In order to quickly form a continuous film across a given surface, several pre-treatments of the substrate have been developed to increase the nucleation density. Amongst those, Bias Enhanced Nucleation (BEN) has been used intensively for many applications, including for instance the synthesis of ultra-thin diamond films, heteroepitaxial diamond films, or nanodiamond films. The determination of the nucleation kinetics during the BEN pretreatment is particularly relevant in order to obtain fundamental informations about plasma/surface interactions and associated nucleation mechanisms. Besides, it is a key challenge to optimise the BEN step for specific applications, such as epitaxy or high nucleation density. The sequential approach which consists of interrupting the process at different time intervals for nucleation density measurement is time consuming and not accurate enough. We propose a real time investigation of diamond nucleation by laser scattering applied to the Bias Enhanced Nucleation (BEN) pre-treatment on silicon carbide. The Microwave Plasma Chemical Vapour Deposition (MPCVD) reactor was equipped with a laser reflectometry system associated with a lock-in laser intensity measurement. In parallel, a kinetics model of nucleation was drawn based on light diffusion of diamond nanoparticles according to their size and density. The modelling results were compared to the experimental data, and characteristic kinetic parameters were worked out for diamond nucleation on silicon carbide. In this study we demonstrated that using a model based on nanoparticles laser scattering it is possible to determine in real time the kinetics of diamond nucleation.     

Defined multi-species semi-liquid ready-to-use sourdough starter

This paper aimed at setting up a protocol for the manufacture of a defined multi-species semi-liquid ready-to-use sourdough starter consisting of lactic acid bacteria (LAB) selected on the basis of their capacity of rapid acidification and adaptation to several technological factors. Preliminarily, 56 strains of sourdough LAB were screened based on the acidification kinetics during sourdough fermentation. The influence of temperature (25-37 degrees C), NaCl (2%, w/w, of wheat flour), initial cell number (10(7)-10(9) cfu g(-1)), dough yield (150-180), substrate for cell cultivation (mMRS or SDB media) and phase of cell growth (exponential or stationary phases) on the kinetics of acidification was also determined. Lactobacillus casei DPPMA27, Weissella confusa DPPMA20 and Lactobacillus fructivorans DPPMA8 were selected and used to produce a defined multi-species semi-liquid sourdough starter. Fermentation was carried out in a 2l batch fermentation bioreactor (12 h at 37 degrees C), under controlled pH, by cultivating cells in a medium made of water (60%), flour and other nutrients (40%). The semi-liquid sourdough starter was stored for 30 days under different conditions and used for dough fermentation (dough yield 160). The microbial composition, acidifying activity and fermentation end-products were kept constant during 21 days of storage. The findings of this study may be useful to increase the use of sourdough in bakery industries.     

Patient-Derived Multiple Myeloma 3D Models for Personalized Medicine—Are We There Yet?

Despite the wide variety of existing therapies, multiple myeloma (MM) remains a disease with dismal prognosis. Choosing the right treatment for each patient remains one of the major challenges. A new approach being explored is the use of ex vivo models for personalized medicine. Two-dimensional culture or animal models often fail to predict clinical outcomes. Three-dimensional ex vivo models using patients’ bone marrow (BM) cells may better reproduce the complexity and heterogeneity of the BM microenvironment. Here, we review the strengths and limitations of currently existing patient-derived ex vivo three-dimensional MM models. We analyze their biochemical and biophysical properties, molecular and cellular characteristics, as well as their potential for drug testing and identification of disease biomarkers. Furthermore, we discuss the remaining challenges and give some insight on how to achieve a more biomimetic and accurate MM BM model. Overall, there is still a need for standardized culture methods and refined readout techniques. Including both myeloma and other cells of the BM microenvironment in a simple and reproducible three-dimensional scaffold is the key to faithfully mapping and examining the relationship between these players in MM. This will allow a patient-personalized profile, providing a powerful tool for clinical and research applications.     

The EQUALANT99 experiment: in situ and satellite data for surface circulation in the tropical Atlantic

In summer 1999, an extensive survey of the tropical Atlantic ocean was operated during the EQUALANT99 cruise. Several experiments were carried out on board including, for the first time in that area, eXpendable Conductivity–Temperature–Depth (XCTD) launches. The aim of this experiment was first to evaluate XCTD temperature and salinity profiles, and secondly to check how XCTD could be used together with altimetric satellite missions in order to capture a good picture of the tropical Atlantic surface circulation.     

Hydrogenation of nanodiamonds using MPCVD: A new route toward organic functionalization

Nanodiamonds (NDs) emerge as excellent candidates for biological applications but their functionalization is still an issue. By analogy with hydrogenated diamond layers, an efficient and homogeneous covalent functionalization can be achieved on hydrogenated NDs. Here is reported an efficient new approach to hydrogenate NDs by reducing all various oxygenated groups into C–H terminations. The hydrogenation treatment is performed by exposing the nanoparticles to microwave hydrogen plasma in the gas phase. The hydrogenation of the nanoparticles has been carefully characterized by FTIR and XPS analysis revealing strong modification and homogenization of their entire surface. To validate this hydrogen treatment, functionalization of the NDs has been conducted by using diazonium reactions. An efficient grafting was observed for the hydrogenated NDs compared to the as-received ones.     

Dietary intakes and food sources of n−6 and n−3 PUFA in french adult men and women

The intake of individual n−6 and n−3 PUFA has been estimated in 4,884 adult subjects (2,099 men and 2,785 women), volunteers from the French SU.VI.MAX intervention trial. The food intakes of each subject were recorded in at least ten 24-h record questionnaires completed over a period of 2.5 yr, allowing the estimation of the daily intake of energy; total fat; and linoleic, α-linolenic, arachidonic, eicosapentaenoic (EPA), n−3 docosapentaenoic (DPA), and docosahexaenoic (DHA) acids. The mean total fat intake corresponded to 94.1 g/d (36.3% of total energy intake) in men and 73.4 g/d (38.1% of energy) in women. The intake of linoleic acid was 10.6 g/d in men and 8.1 g/d in women, representing 4.2% of energy intake; that of α-linolenic acid was 0.94 g/d in men and 0.74 g/d in women, representing 0.37% of energy intake, with a mean linoleic/α-linolenic acid ratio of 11.3. The mean intakes of long-chain PUFA were: arachidonic acid, 204 mg/d in men and 152 mg/d in women; EPA, 150 mg/d in men and 118 mg/d in women; DPA, 75 mg/d in men and 56 mg/d in women; DHA, 273 mg/d in men and 226 mg/d in women; long-chain n−3 PUFA, 497 mg/d in men and 400 mg/d in women. Ninety-five percent of the sample consumed less than 0.5% of energy as α-linolenic acid, which is well below the current French recommendation for adults (0.8% of energy). In contrast, the mean intakes of long-chain n−6 and n−3 PUFA appear fairly high and fit the current French recommendations (total long-chain PUFA: 500 mg/d in men and 400 mg/d in women; DHA: 120 mg/d in men and 100 mg/d in women). The intakes of α-linolenic acid, and to a lesser extent of linoleic acid, were highly correlated with that of lipids. Whereas the main source of linoleic acid was vegetable oils, all food types contributed to α-linolenic acid intake, the main ones being animal products (meat, poultry, and dairy products). The main source of EPA and DHA (and of total long-chain n−3 PUFA) was fish and seafood, but the major source of DPA was meat, poultry, and eggs. Fish and seafood consumption showed very large interindividual variations, the low consumers being at risk of insufficient n−3 PUFA intake.