OXIDATION CHEMISTRY IN ASPHALT

A possible mechanism of asphalt oxidation with O₂ or photo-excited O₂ is presented herein. The oxidation reaction will occur via an allowed reaction pathway -charge-transfer (CT) complexes. Oxidation reactions transform the sulfur-containing compounds from electron donors to electron acceptors - sulfoxides. These new electron acceptors form CT complexes with electron donors, particularly nitrogen-containing compounds and aromatic compounds. An increase in the average molecular weight after oxidation of asphalt may be due to the formation of CT complex. Treatment with H₂SO₄ or p-chloranil increases the electron acceptor concentration in asphalt. The resulting products show extremely large increases in viscosity. ESR studies show decreases in the signal intensity ratio of vanadyl porphyrins to free radicals in asphalt after oxidation. The decrease in this ratio may be due to the formation of CT complexes. The introduction of deactivating groups such as nitro or fluoro functional groups, or hydroquinone in asphalt will increase the elastic recovery of original asphalt and thin film oven test residues. These results suggest that the rheological properties of asphalt can be strongly affected by controlling the formation of CT complexes.     

Use of a Novel Extremophilic Xylanase for an Environmentally Friendly Industrial Bleaching of Kraft Pulps

Xylanases can boost pulp bleachability in Elemental Chlorine Free (ECF) processes, but their industrial implementation for producing bleached kraft pulps is not straightforward. It requires enzymes to be active and stable at the extreme conditions of alkalinity and high temperature typical of this industrial process; most commercial enzymes are unable to withstand these conditions. In this work, a novel highly thermo and alkaline-tolerant xylanase from Pseudothermotoga thermarum was overproduced in E. coli and tested as a bleaching booster of hardwood kraft pulps to save chlorine dioxide (ClO₂) during ECF bleaching. The extremozyme-stage (EXZ) was carried out at 90 °C and pH 10.5 and optimised at lab scale on an industrial oxygen-delignified eucalyptus pulp, enabling us to save 15% ClO₂ to reach the mill brightness, and with no detrimental effect on paper properties. Then, the EXZ-assisted bleaching sequence was validated at pilot scale under industrial conditions, achieving 25% ClO₂ savings and reducing the generation of organochlorinated compounds (AOX) by 18%, while maintaining pulp quality and papermaking properties. Technology reproducibility was confirmed with another industrial kraft pulp from a mix of hardwoods. The new enzymatic technology constitutes a realistic step towards environmentally friendly production of kraft pulps through industrial integration of biotechnology.     

Overexpression of Nucleolin and Associated Genes in Prostate Cancer

Prostate cancer (PCa) is the second most frequent cancer and the fifth leading cause of cancer death in men worldwide. If local PCa presents a favorable prognosis, available treatments for advanced PCa display limiting benefits due to therapeutic resistances. Nucleolin (NCL) is a ubiquitous protein involved in numerous cell processes, such as ribosome biogenesis, cell cycles, or angiogenesis. NCL is overexpressed in several tumor types in which it has been proposed as a diagnostic and prognostic biomarker. In PCa, NCL has mainly been studied as a target for new therapeutic agents. Nevertheless, little data are available concerning its expression in patient tissues. Here, we investigated the expression of NCL using a new cohort from Mondor Hospital and data from published cohorts. Results were then compared with NCL expression using in vitro models. NCL was overexpressed in PCa tissues compared to the normal tissues, but no prognostic values were demonstrated. Nine genes were highly co-expressed with NCL in patient tissues and tumor prostate cell lines. Our data demonstrate that NCL is an interesting diagnostic biomarker and propose a signature of genes co-expressed with NCL.     

Review on modelling of corrosion under droplet electrolyte for predicting atmospheric corrosion rate

Atmospheric corrosion of metals is the most common type of corrosion which has a significant impact on the environment and operational safety in various situations of everyday life.Some of the common examples can be observed in land,water and air transportation systems,electronic circuit boards,urban and offshore infrastructures.The dew drops formed on metal surface due to condensation of atmospheric moisture facilitates corrosion as an electrolyte.The corrosion mechanisms under these droplets are different from classically known bulk electrolyte corrosion.Due to thin and non-uniform geometric thickness of the droplet electrolyte,the atmospheric oxygen requires a shorter diffusion path to reach the metal surface.The corrosion under a droplet is driven by the depletion of oxygen in the center of the droplet compared to the edge,known as differential aeration.In case of a larger droplet,differential aeration leads to preferential cathodic activity at the edge and is controlled by the droplet geometry.Whereas,for a smaller droplet,the oxygen concentration remains uniform and hence cathodic activity is not controlled by droplet geometry.The geometry of condensed droplets varies dynamically with changing environmental parameters,influencing corrosion mechanisms as the droplets evolve in size.In this review,various modelling approaches used to simulate the corrosion under droplet electrolytes are presented.In the efforts of developing a comprehensive model to estimate corrosion rates,it has been noted from this review that the influence of geometric evolution of the droplet due to condensation/evaporation processes on corrosion mechanisms are yet to be modelled.Dynamically varying external factors like environmental temperature,relative humidity,presence of hygroscopic salts and pollutants influence the evolution of droplet electrolyte,making it a complex phenomenon to investigate.Therefore,an overview of available dropwise condensation and evaporation models which describes the formation and the evolution of droplet geometry are also presented from an atmo s pheric corrosion viewpoint.     

Does the Financial Times FT50 journal list select the best management and economics journals?

Scientometrics - The ranking of academic journals and the considerable impact of journal lists have been increasingly criticized, especially in management research. To assess the effectiveness of...     

The impact of review articles in management and economics journal rankings and metrics

Scientometrics - In a letter to the editor, Moussa (2021) questions the impact of review articles on the ranking and indicators of journals. Applied to the management and economics FT50 journals...     

Effect of γ phase on mechanical behavior and detwinning evolution of directionally solidified Ni-Mn-Ga alloys under uniaxial compression

Specimens with single-phase martensite, net-like γ/martensite mixed structure and lamella-likeγ/martensite mixed structure were designed to investigate the effect of the γ phase on the mechanical behavior and the detwinning of non-modulated(NM) martensitic variant in Ni-rich Ni-Mn-Ga alloys under uniaxial compression. It can be found the existence of the γ phase significantly enhances the compressive stresses, and the net-like γ phase specimen presents a higher value of compressive strain than that of the lamella-like γ phase specimen. Especially, the detwinning plateau of the lamella-like γ phase specimen is almost invisible due to the martensite colonies with low Schmid factors. Finally, according to the calculation of deformation gradient tensor, we found that the tensors along compression direction(εzz) of net-like γ phase/martensite mixed structure specimen and single-phase martensite specimen are lower than that of the specimen with lamella-like γ phase/martensite mixed structure, which well explained the detwinning strain for these specimens. The present study not only highlights the role ofγ phase on the mechanical behavior, but also provides more guidelines for the mechanical training of Ni-Mn-Ga shape memory alloys.     

Linear stability analysis of mixed convection flow in a horizontal channel filled with nanofluids

The convective instability driven by buoyancy in the Poiseuille–Rayleigh–Bénard flow through two infinite parallel horizontal plates filled with nanofluids is investigated using linear stability analysis. We considered water‐based nanofluids with different volume fractions of aluminum ( $\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3$) and silver ( $\mathrm{A}\mathrm{g}$) nanoparticles. A spectral collocation method founded on Chebyshev polynomials is implemented and the obtained algebraic eigenvalue problem is solved. In this study, we have numerically determined the critical Rayleigh number of the onset of longitudinal and transversal rolls and the results are represented in the form of marginal stability curves. Critical wave numbers that describe the size of convective cells in the flow are also presented, analyzed, and compared with those of the Poiseuille–Rayleigh–Bénard flow without nanoparticles. The effects of the type and nanoparticle volume fractions on the onset of both longitudinal and transversal rolls are investigated.     

Evaluation of 5H-Thiazolo[3,2-α]pyrimidin-5-ones as Potential GluN2A PET Tracers

We describe here our efforts to develop a PET tracer for imaging GluN2A-containing NMDA receptors, based on a 5H-thiazolo[3,2-α]pyrimidin-5-one scaffold. The metabolic stability and overall properties could be optimized satisfactorily, although binding affinities remained a limiting factor for in vivo imaging. We nevertheless identified 7-(((2-fluoroethyl)(3-fluorophenyl)amino)-methyl)-3-(2-(hydroxymethyl)cyclopropyl)-2-methyl-5H-thiazolo-[3,2-α]pyrimidin-5-one ([¹⁸F] 7b ) as a radioligand providing good-quality images in autoradiographic studies, as well as a tritiated derivative, 2-(7-(((2-fluoroethyl)(4-fluorophenyl)amino)methyl)-2-methyl-5-oxo-5H-thiazolo[3,2-α]pyrimidin-3-yl)cyclopropane-1-carbonitrile ([³H₂] 15b ), which was used for the successful development of a radioligand binding assay. These are valuable new tools for the study of GluN2A-containing NMDA receptors, and for the optimization of allosteric modulators binding to the pharmacophore located at the dimer interface of the GluN1-GluN2A ligand-binding domain.