Performance of a silicon monochromator under high heat load

The performance of a cryogenically cooled double‐crystal silicon monochromator was studied under high‐heat‐load conditions with total absorbed powers and power densities ranging from 8 to 780 W and from 8 to 240 W mm^?2, respectively. When the temperature of the first crystal is maintained close to the temperature of zero thermal expansion of silicon, the monochromator shows nearly ideal performance with a thermal slope error of 0.6 µrad. By tuning the size of the first slit, the regime of the ideal performance can be maintained over a wide range of heat loads, i.e. from power densities of 110 W mm^?2 (at total absorbed power of 510 W) to 240 W mm^?2 (at total absorbed power of 240 W).     

Solid-Liquid Phase Transfer Catalysis Without Solvent: Further Improvement in SNAr Reactions

Solid-liquid PTC without added solvent efficiently promotes SNAr reactions of a variety of anionic nucleophiles generated in situ. This methodology is applied with success to some examples concerning non-activated aromatic systems. TDA-1 is the most effective catalyst.     

Calcium-based hydrated minerals: Promising halogen-free flame retardant and fire resistant additives for polyethylene and ethylene vinyl acetate copolymers

In this study, we evaluated the potential flame retardant effect of calcium-based hydrated minerals, such as hydrated lime, partially and completely hydrated dolomitic limes in polyethylene (MDPE) and ethylene vinyl acetate copolymers (EVA) and compared to that obtained with magnesium di-hydroxide (MDH). The most significant flame retardant effects, observed using the mass loss calorimeter test, indicated that Ca-based MDPE composites showed similar peak Heat Release Rate (pHRR) level to that obtained with MDH composite while the pHRR was lower for Ca-based fillers in EVA compositions. X-ray Diffraction (XRD) data, combined with thermal analysis results, indicated that the calcium di-hydroxide plays a role in the formation of an intumescent cohesive residue during the combustion. Indeed, Ca(OH)₂ reacts with CO₂ formed during the thermal degradation of the polymer to generate CaCO₃ (calcium carbonate) that contributes to the enhancement of the mechanical resistance of the residue.     

Aerodynamic optimization of the flat-plate leading edge for experimental studies of laminar and transitional boundary layers

This work is concerned with the design of a leading edge for a flat-plate model used to study laminar and transitional boundary layers. For this study, the flow over the complete boundary-layer model, including leading edge, flat section, and trailing-edge flap, is modeled. The effect of important geometrical features of the leading edge on the resulting pressure distribution, starting from the well-known symmetric modified super ellipse, is investigated. A minimal pressure gradient on the measurement side of the plate is achieved using an asymmetrical configuration of modified super ellipses, with a thickness ratio of 7/24. An aerodynamic shape optimization is performed to obtain a novel leading edge shape that greatly reduces the length of the non-zero pressure gradient region and the adverse pressure gradient region compared to geometries defined by ellipses. Wind tunnel testing is used to validate the numerical solutions.     

Physical complexity of variable length symbolic sequences

A measure called physical complexity is established and calculated for a population of sequences, based on statistical physics, automata theory, and information theory. It is a measure of the quantity of information in an organism’s genome. It is based on Shannon’s entropy, measuring the information in a population evolved in its environment, by using entropy to estimate the randomness in the genome. It is calculated from the difference between the maximal entropy of the population and the actual entropy of the population when in its environment, estimated by counting the number of fixed loci in the sequences of a population. Up until now, physical complexity has only been formulated for populations of sequences with the same length. Here, we investigate an extension to support variable length populations. We then build upon this to construct a measure for the efficiency of information storage, which we later use in understanding clustering within populations. Finally, we investigate our extended physical complexity through simulations, showing it to be consistent with the original.     

A Synthetic Substrate of DNA Polymerase Deviating from the Bases,Sugar, and Leaving Group of Canonical Deoxynucleoside Triphosphates

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Highlights? A highly modified nucleotide as substrate for polymerases ? The reversibility of the polymerase reaction at the template level ? Synthesis of a nucleoside with two anomeric centers     

N-Glycosidase treatment with 18O labeling and de novo sequencing argues for flagellin FliC glycopolymorphism in Pseudomonas aeruginosa

In prokaryote organisms, N-glycosylation of proteins is often correlated to cell–cell recognition and extracellular events. Those glycoproteins are potential targets for infection control. To date, many surface-glycosylated proteins from bacterial pathogens have been described. However, N-linked Pseudomonas surface-associated glycoproteins remain underexplored. We report a combined enrichment and labeling strategy to identify major glycoproteins on the outside of microorganisms. More precisely, bacteria were exposed to a mix of biotinylated lectins able to bind with glycoproteins. The latter were then recovered by avidin beads, digested with trypsin, and submitted to mass spectrometry. The targeted mixture of glycoproteins was additionally deglycosylated in the presence of H₂ ¹⁸O to incorporate ¹⁸O during PNGase F treatment and were also analyzed using mass spectrometry. This approach allowed us to identify a few tens of potential N-glycoproteins, among which flagellin FliC was the most abundant. To detect the possible sites of FliC modifications, a de novo sequencing step was also performed to discriminate between spontaneous deamidation and N-glycan loss. This approach led to the proposal of three potential N-glycosylated sites on the primary sequence of FliC: N26, N69, and N439, with two of these three asparagines belonging to an N-X-(S/T) consensus sequence. These observations suggest that flagellin FliC is a heterogeneous protein mixture containing both O- and N-glycoforms.