Gold supported on carbon nanotubes for the selective oxidation of glycerol

Gold nanoparticles were supported on multi-walled carbon nanotubes (MWCNTs) by different methods and tested in the selective oxidation of glycerol under basic conditions, with the main purpose of evaluating the effect of the preparation technique on the activity and selectivity. The catalytic performances largely depended on the gold crystallite size. The sol immobilization method was the most suitable technique to prepare gold supported on carbon nanotubes. The use of MWCNTs as support for Au nanoparticles resulted in the oxidation of the secondary hydroxyl group, and therefore, a remarkable high dihydroxyacetone selectivity of about 60% is obtained independently of the preparation method used. A possible explanation based on the peculiar characteristics of the support is proposed. It was also concluded that dihydroxyacetone in the final mixture can be stabilized by lowering the pH to about 3.     

Four new SYBR<Superscript>®</Superscript>Green qPCR screening methods for the detection of Roundup Ready<Superscript>®</Superscript>, LibertyLink<Superscript>®</Superscript>, and CryIAb traits in genetically modified products

SYBR^®Green qPCR methods for the detection of the Roundup Ready^® “CP4-EPSPS”, LibertyLink^® “PAT” and “BAR,” and the Bacillus thuringiensis “CryIAb” traits as present in genetically modified organisms (GMO) were developed. Their specificity, sensitivity, and PCR method efficiency were determined. All methods are specific and generate amplicons of 108, 73, 109, and 69 bp, respectively, for “CP4-EPSPS,” “CryIAb,” “PAT,” and “BAR” targets. They perform well at low target levels and can detect down to 5 copies of their respective targets extracted from a sample. The PCR efficiency of the methods ranges between 91 and 109%. Due to their trait-specific nature, these methods allow an efficient screening between the different GMO. In this way, the number of possible GMO candidates present in a sample can be reduced what results in lower global costs due to limiting of further the number of analytical identification steps. The application of these methods in CoSYPS GMO analysis is illustrated using two GEMMA proficiency test samples and a reference material from the GM rapeseed event RF3. This set of SYBR^®Green qPCR trait-specific methods represents a very interesting novel set of GMO analysis methods allowing cost-effective identification of GM materials in products.     

Oxidation resistance of Ti3AlC2 and Ti3Al0.8Sn0.2C2 MAX phases: A comparison

Ti₃AlC₂ and Ti₃Al_0.8Sn_0.2C₂ MAX phase powders are densified using Spark Plasma Sintering (SPS) technique to obtain dense bulk materials. Oxidation tests are then performed over the temperature range 800°C-1000°C under synthetic air on the two different materials in order to compare their oxidation resistance. It is demonstrated that, in the case of the Ti₃Al_0.8Sn_0.2C₂ solid solution, the oxide layers consist in TiO₂, Al₂O₃, and SnO₂. The presence of Sn atoms in the A planes of the solid solution leads to an easy diffusion of Sn out of the MAX phase which promote the formation of the nonprotective and fast growing SnO₂ oxide. Moreover, the small Al/Ti atom's ratio promotes the growth of a nonprotective rutile-TiO₂ scale as well. In the case of the Ti₃AlC₂ MAX phase, the oxide layer consists in a protective alumina scale; a few TiO₂ grains being observed on the top of the Al₂O₃ layer. The parabolic oxidation rate constants are about 3 orders of magnitude smaller for Ti₃AlC₂ compared to Ti₃Al_0.8Sn_0.2C₂.     

Cationic UV‐curing of epoxidized cardanol derivatives

This paper demonstrates the high reactivity and potentiality of bio‐renewably obtained cardanol‐based epoxy monomers as well as the possibility of tuning the final thermomechanical properties by changing either the epoxy content or the chemical structure of the starting photocurable resin. The reactivity of the cardanol monomers towards the cationic UV‐curing process was investigated by Fourier transform IR analysis and it was shown that a high epoxy group conversion was achieved. Furthermore, the thermomechanical properties were investigated on crosslinked films by means of DSC and dynamic thermomechanical analysis. © 2020 Society of Chemical Industry     

Cobalt‐Catalyzed Reductive Cross‐Coupling Between Benzyl Chlorides and Aryl Halides

A new protocol for the direct reductive cobalt‐catalyzed arylation of benzyl chlorides has been developed in order to form functionalized diarylmethanes. A variety of reactive groups either on the aryl or the benzyl halide was employed. This represents the first cobalt‐catalyzed reductive cross‐coupling which does not require any ligand and pyridine. A reaction pathway is proposed involving a radical benzyl species.

     

Surface film formation on electrodes in a LiCoO2/graphite cell: A step by step XPS study

In this paper, we report on a study of the electrode/electrolyte interfaces of a LiCoO₂/C cell using XPS (X-ray photoelectron spectroscopy). The originality of our work lies in detailed investigations step by step during the first cycle. The results have shown that the formation process of the SEI takes place in different successive stages that are dependent on the potential of the cell. It clearly appears that SEI formation continues in the potential range where lithium ion intercalation proceeds in the carbon electrode. Salt degradation products are formed after solvent decomposition ones. Concerning the LiCoO₂/electrolyte interface, the results obtained have shown the formation of a very thin film on the active material but not on the binders. In all cases, the novel XPS approach applied in the lab, combining core peaks and valence band analyses, allows a precise characterization of the main chemical species of the interface layers. On the basis of these results and in conjunction with literature data, the degradation mechanisms have been discussed.     

EU demonstration project for separate discharge and treatment of urine, faeces and greywater--part I: results.

The main aim of this EU demonstration project was to test two new sanitation concepts to determine if these concepts are more sustainable, compared with the conventional sanitation system, particularly with regard to nutrient recycling. Two different sanitation concepts were tested. One concept comprised the use of gravity separation toilets, the other used vacuum separation toilets. Results from a life-cycle-assessment investigation show that the new sanitation concepts are more sustainable. A cost analysis for an existing residential area did not prove lower costs for the new sanitation concepts in this special case. The experience from this demonstration project shows that prior to a widespread use of the new sanitation concepts, several improvements have to be made. One important issue is the improvement of separation toilets. Since nutrient recycling, water saving and reuse as well energy reduction become more and more important, further research should be undertaken in this field.     

Comparative Genomics of Eight Fusarium graminearum Strains with Contrasting Aggressiveness Reveals an Expanded Open Pangenome and Extended Effector Content Signatures

Fusarium graminearum, the primary cause of Fusarium head blight (FHB) in small-grain cereals, demonstrates remarkably variable levels of aggressiveness in its host, producing different infection dynamics and contrasted symptom severity. While the secreted proteins, including effectors, are thought to be one of the essential components of aggressiveness, our knowledge of the intra-species genomic diversity of F. graminearum is still limited. In this work, we sequenced eight European F. graminearum strains of contrasting aggressiveness to characterize their respective genome structure, their gene content and to delineate their specificities. By combining the available sequences of 12 other F. graminearum strains, we outlined a reference pangenome that expands the repertoire of the known genes in the reference PH-1 genome by 32%, including nearly 21,000 non-redundant sequences and gathering a common base of 9250 conserved core-genes. More than 1000 genes with high non-synonymous mutation rates may be under diverse selection, especially regarding the trichothecene biosynthesis gene cluster. About 900 secreted protein clusters (SPCs) have been described. Mostly localized in the fast sub-genome of F. graminearum supposed to evolve rapidly to promote adaptation and rapid responses to the host’s infection, these SPCs gather a range of putative proteinaceous effectors systematically found in the core secretome, with the chloroplast and the plant nucleus as the main predicted targets in the host cell. This work describes new knowledge on the intra-species diversity in F. graminearum and emphasizes putative determinants of aggressiveness, providing a wealth of new candidate genes potentially involved in the Fusarium head blight disease.