Corrosion of pure iron in fused sodium methaphosphate

The analytical and potentiometric study (using an Ag/Ag⁺ reference electrode) of the behaviour of pure iron in molten sodium metaphosphate at 750°C shows that a non-polarized electrode corrodes: iron is oxidized to soluble Fe²⁺ ions and, simultaneously, an Fe₂P and FeP₂ deposit resulting from phosphate anion reduction is formed on the electrode surface.The variations of the mixed potential and of the total mass of oxidized iron show that the corrosion rate decreases as the immersion time increases. Such an inhibition comes from the gradual coating of the electrode surface with the iron phosphides: the corrosion rate is controlled by the iron diffusion through the deposit, the thickness of which increases with time.     

Compact adaptive optical system based on blind optimization and a micromachined membrane deformable mirror

We describe and demonstrate an adaptive optical system based on the combination of a micromachined membrane deformable mirror and the stochastic parallel gradient descent control algorithm. This compact and relatively inexpensive adaptive optical system is used to maximize the coupling of a distorted laser beam into a single-mode optical fiber. The coupling efficiency is improved by 12 dB, and the coupling efficiency after correction is 64% of the diffraction-limited coupling efficiency.     

Monocular Vision for Mobile Robot Localization and Autonomous Navigation

This paper presents a new real-time localization system for a mobile robot. We show that autonomous navigation is possible in outdoor situation with the use of a single camera and natural landmarks. To do that, we use a three step approach. In a learning step, the robot is manually guided on a path and a video sequence is recorded with a front looking camera. Then a structure from motion algorithm is used to build a 3D map from this learning sequence. Finally in the navigation step, the robot uses this map to compute its localization in real-time and it follows the learning path or a slightly different path if desired. The vision algorithms used for map building and localization are first detailed. Then a large part of the paper is dedicated to the experimental evaluation of the accuracy and robustness of our algorithms based on experimental data collected during two years in various environments.     

Computing Longest Previous Factor in linear time and applications

We give two optimal linear-time algorithms for computing the Longest Previous Factor (LPF) array corresponding to a string w. For any position i in w, LPF[i] gives the length of the longest factor of w starting at position i that occurs previously in w. Several properties and applications of LPF are investigated. They include computing the Lempel-Ziv factorization of a string and detecting all repetitions (runs) in a string in linear time independently of the integer alphabet size.     

Degradation Products of Tryptophan in Cell Culture Media: Contribution to Color and Toxicity

Biomanufacturing processes may be optimized by storing cell culture media at room temperature, but this is currently limited by their instability and change in color upon long-term storage. This study demonstrates that one of the critical contributing factors toward media browning is tryptophan. LC-MS technology was utilized to identify tryptophan degradation products, which are likely formed primarily from oxidation reactions. Several of the identified compounds were shown to contribute significantly to color in solutions but also to exhibit toxicity against CHO cells. A cell-culture-compatible antioxidant, a-ketoglutaric acid, was found to be an efficient cell culture media additive for stabilizing components against degradation, inhibiting the browning of media formulations, and decreasing ammonia production, thus providing a viable method for developing room-temperature stable cell culture media.     

In vitro activity of 9 antibiotics and 3 beta-lactamase inhibitors against 107 clinical isolates of Acinetobacter baumanii

Twenty eight of 227 patients undergoing restorative proctocolectomy for inflammatory bowel disease, familial adenomatous polyposis or functional disease were over the age of 50 years: ages 50 to 60 (n = 13), 60 to 70 (n = 10), and over 70 (n = 5). Major complications occurred in 5 patients over the age of 50 (18%) compared with 43 patients under the age of 50 (23%). Three patients above the age of 50 had their pouch excised (11%) compared with 23 under the age of 50 (12%). Functional outcome was assessed with a 12 point symptom score. This was similar in all age bands: under 50 years (mean = 2.2; sd +/- 2.2; n = 109), 50 to 60 years (mean = 2.5; sd +/- 2.5; n = 12), 60 to 70 years (mean = 2.8; sd +/- 2.3; n = 7) and over 70 years (mean = 4.0; sd +/- 3.7; n = 5): P > 0.05). When analysed for ulcerative colitis alone, no significant differences were seen between the two age groups. Restorative proctocolectomy in the elderly gives results which are comparable to the younger population.     

Application de la voltampérométrie convolutionnele à la détermination du coefficient de diffusion des ions TiF 6 3− dans l'eutectique LiF−NaF−KF de 600°C a 900°C

Résumé Les coefficients de diffusion des ions TiF ₆ ^3– dans l'eutectique LiF–NaF–KF ont été déterminés de 600 à 900° C à l'aide de la semi-intégration des voltampérogrammes de réduction sur électrode de fer et d'oxydation sur électrode d'argent. Les interférences de la réduction de l'eutectique et d'un ménisque à la surface du bain ont été éliminées. Le coefficient de diffusion des ions TiF ₆ ^3– obéit à la loi d'Arrhénius selon:D=1.4×10^–2 exp (–6154/T) cm² s^–1.     

Synthesis,Chiral Separation,Absolute Configuration Assignment,and Biological Activity of Enantiomers of Retro‐1 as Potent Inhibitors of Shiga Toxin

The Shiga toxin (Stx) family is composed of related protein toxins produced by the bacteria Shigella dysenteriae and certain pathogenic strains of E. coli. No effective therapies for Stx intoxication have been developed yet. However, inhibitors that act on the intracellular trafficking of these toxins may provide new options for the development of therapeutic strategies. This study reports the synthesis, chromatographic separation, and pharmacological evaluation of the two enantiomers of Retro‐1, a compound active against Stx and other such protein toxins. Retro‐1 works by inhibiting retrograde transport of these toxins inside cells. In vitro experiments proved that the configuration of the stereocenter at position 5 is not crucial for the activity of this compound. X‐ray diffraction data revealed (S)‐Retro‐1 to be slightly more active than (R)‐Retro‐1.     

On the influence of gamma prime upon machining of advanced nickel based superalloy

Whilst gamma prime (γ′) phase is the strengthening phase in Ni-based superalloys its influence on machining has been seldom investigated. This paper reports for the first time on the effect of γ′ upon machining of Ni-based superalloys when cutting with parameters yielding different cutting temperature intervals which lead to strengthening/softening effects on the workpiece (sub)surface. In-depth XRD, SEM/FIB, EBSD analysis and unique micro-pillar testing in the workpiece superficial layers indicated that with the increase of γ′ fraction the grain plastic deformation significantly decreased, while specific cutting energy can switch from low to high values influenced by the real cutting temperature.