Measurable surface d charge of Pd as a descriptor for the selective hydrogenation activity of quinoline

Au Pd nanoalloys with tunable Pd concentrations have been synthesized and used as model catalysts. They have been directly imaged by high-angle annular dark-field scanning transmission electron microscopy and investigated by thorough analyses of their extended X-ray absorption fine structure, X-ray absorption near-edge structure, X-ray diffraction and X-ray photoelectron spectroscopy measurements. The bimetallic nanoparticles are embedded in a carbonaceous matrix and have almost an identical structure at the atomic level and the same electronic properties as Au Pd bulk alloys with the same compositions. The d-electron increase at surface Pd sites is determined by the Pd concentration of the alloy. Similarly, their activation entropy and catalytic activity for the hydrogenation of quinoline is related to the Pd concentration, with Au50 Pd50 the most active of the alloys investigated. An almost 11 times higher activity was achieved compared to a pure Pd catalyst. The experimentally measurable surface d charge at the Pd sites in the Au Pd was found to linearly correlate with the activation entropy and catalytic activity for the hydrogenation of quinoline. The alloy structure is stable, showing negligible metal segregation, dissolution-redeposition and aggregation during the hydrogenation process which involves strong adsorption.

Effects of Different Water-saving Irrigation Methods on Fruit Quality and Yield of Snow Melon

[Objectives]This study was conducted to explore the most suitable irrigation integration mode for"Tinglin snow melon"in Jinshan District,Shanghai City.[Methods]With the field water holding capacity as the standard,different upper limits of irrigation were set in the four growth stage of snow melon to investigate the effects of such three water-saving irrigation modes as single-row drip irrigation pipes,double-row drip irrigation pipes and drip arrows on the traits and yield of melon plants under the same growth conditions.[Results]The results showed that different irrigation modes had certain effects on the growth,comprehensive quality and yield of snow melon,and the drop arrow mode was better than other two modes.Under the drop arrow mode,the number of snow melons was the highest,7.34 per plant,and the yield was the highest,reaching 15463.35 kg/hm^(2),showing the best yield increasing effect.In addition,the contents of soluble solids and vitamin C in the drop arrow mode were higher than those in the drip irrigation pipe mode.[Conclusions]Compared with other irrigation methods,the drop arrow mode was more suitable for the production of snow melon.

Trimming of N-Glycans by the Golgi-Localized α-1,2-Mannosidases, MNS1 and MNS2, Is Crucial for Maintaining RSW2 Protein Abundance during Salt Stress in Arabidopsis

Asparagine （Asn/N）-Iinked glycans are important for protein folding, trafficking, and endoplasmic reticulum-associated degradation in eukaryotes. The maturation of glycoproteins involves the trimming of mannosyl residues by mannosidases and addition of other sugar molecules to three-branched N-glycans in the Golgi. However, the biological importance of Golgi-mediated mannose trimming is not fully understood. Here, we show that abolishment of two functionally redundant mannosidases, MNS1 and MNS2, responsible for α-1,2-mannose trimming on the A and C branches of plant N-glycans lead to severe root growth inhibition under salt stress conditions in Arabidopsis. In contrast, mutants with defects in the biosynthesis of the oligosaccharide precursor displayed enhanced salt tolerance in the absence of mannose trimming. However, mutation in EBS3, which is required for the formation of the branched N-glycan precursor, suppressed the salt-sensitive phenotype of mnsl mns2 double mutant. Interestingly, we observed that cellulose biosynthesis was compromised in mnsl mns2 roots under high salinity. Consistently, abundance of a membrane anchored endo-13-1,4-endoglucanase （RSW2/KOR） that plays a key role in cellulose biosynthesis and its mutant variant rsw2-1 were modulated by α-1,2-mannose trimming under salt stress. Overexpression of RSW2 could partially rescue the salt-sensitive phenotype of mnsl mns2. Taken together, these results suggest that MNS1/2-mediated mannose trimming of N-glycans is crucial in modulating glycoprotein abundance to withstand salt stress in plants.

Cellulose-based hydrogels regulated by supramolecular chemistry

Supramolecular hydrogels based on cellulose attract increasing attention because of their novel structures and broad potential applications.In this review,hydrogels composed of cellulose are summarized according to category of supramolecular interactions in the networks including hydrogen bonds,electrostatic interactions,host-guest interactions,and others.Supramolecular cellulose-based hydrogels constructed by noncovalent bonding usually exhibit environmental friendliness,designing flexibility and diverse functions,and their properties are variable with incorporating different interactions in hydrogel networks.Moreover,with proper structures and networks,the supramolecular cellulose-based hydrogels are adaptable in diverse fields of research and practical applications,such as self-healing,shape memory,drug delivery,and some other renewable/sustainable materials.The future developments and challenges of the supramolecular hydrogels based on cellulose are discussed as well.