Photocontrollable J-Aggregation of a Diarylethene–Phthalocyanine Hybrid and Its Aggregation-Stabilized Photochromic Behavior

The photocontrollable J-aggregation of a diarylethene–phthalocyanine hybrid (T-ZnPc) and its aggregation-stabilized photochromic behavior were investigated by various techniques. T-ZnPc initially exhibited slight J-aggregation tendency in solvents such as chloroform and toluene through conformational planarization effect, but formed much stronger J-aggregates upon the illumination of 254 nm UV light. In darkness, the UV-irradiated solutions gradually returned to their initial state. These phenomena can be explained by the pronounced change in molecular planarity accompanying the reversible isomerization of the diarylethene units of T-ZnPc. Besides, we have found that the thermal stability of the closed-ring diarylethene isomers in molecularly dispersed T-ZnPc is much poorer than that in aggregates. As long as the aggregates were broken, they converted to corresponding open-ring form instantly. This study provided an example of fully photocontrollable aggregation of phthalocyanines and paved a new way for improving the stability of the photochromic systems

Fabrication of Hierarchical CaCO₃ Mesoporous Spheres: Particle-Mediated Self-Organization Induced by Biphase Interfaces and SAMs

Highly ordered hierarchical calcium carbonate is an important phase involved in calcification by a wide variety of invertebrate organisms, and its formation is of technological interest in the development of functional materials. In this article, porous CaCO3 hierarchical microspheres with a hedgehoglike appearance have been fabricated on the flexible substrate under mild conditions. There are two points that play important roles in the regular organization of the terminal products: one is the biphase interfaces, which are generated by organic solvent n-hexane and an aqueous saturated solution of Ca(OH)2, and the other is hydroxyl-terminated monolayers assembled on the flexible PET (poly(ethylene terephthalate)) substrate. The SEM images show that novel CaCO3 hierarchical microspheres consist of densely stacked “shuttles” by the oriented self-organization of CaCO3 nanoparticles. The IR and XRD spectra indicate that the as-synthesized products are composed of a calcite phase obtained by an ACC (amorphous calcium carbonate)-to-calcite transformation. In view of the results, a nanoparticle-mediated self-organization process induced by biphase interfaces and SAMs template is proposed for the integration of functional materials and nanodevices

Surface Modification of Bacterial Cellulose Aerogels’ Web-like Skeleton for Oil/Water Separation

The cellulose nanofibers of bacterial cellulose aerogel (BCA) are modified only on their surfaces using a trimethylsilylation reaction with trimethyichlorosilane in liquid phase followed by freeze-drying. The obtained hydrophobic bacterial cellulose aerogels (HBCAs) exhibit low density (≤6.77 mg/cm³), high surface area (≥169.1 m²/g), and high porosity (≈ 99.6%), which are nearly the same as those of BCA owing to the low degrees of substitution (≤0.132). Because the surface energy of cellulose nanofibers decreased and the three-dimensional web-like microstructure, which was comprised of ultrathin (20–80 nm) cellulose nanofibers, is maintained during the trimethylsilylation process, the HBCAs have hydrophobic and oleophilic properties (water/air contact angle as high as 146.5°) that endow them with excellent selectivity for oil adsorption from water. The HBCAs are able to collect a wide range of organic solvents and oils with absorption capacities up to 185 g/g, which depends on the density of the liquids. Hence, the HBCAs are wonderful candidates for oil absorbents to clean oil spills in the marine environment. This work provides a different way to multifunctionalize cellulose aerogel blocks in addition to chemical vapor deposition method

Table_1_Genome-wide characterization of L-aspartate oxidase genes in wheat and their potential roles in the responses to wheat disease and abiotic stresses.xlsx

L-aspartate oxidase (AO) is the first enzyme in NAD+ biosynthesis and is widely distributed in plants, animals, and microorganisms. Recently, AO family members have been reported in several plants, including Arabidopsis thaliana and Zea mays. Research on AO in these plants has revealed that AO plays important roles in plant growth, development, and biotic stresses; however, the nature and functions of AO proteins in wheat are still unclear. In this study, nine AO genes were identified in the wheat genome via sequence alignment and conserved protein domain analysis. These nine wheat AO genes (TaAOs) were distributed on chromosomes 2, 5, and 6 of sub-genomes A, B, and D. Analysis of the phylogenetic relationships, conserved motifs, and gene structure showed that the nine TaAOs were clustered into three groups, and the TaAOs in each group had similar conserved motifs and gene structure. Meanwhile, the subcellular localization analysis of transient expression mediated by Agrobacterium tumetioniens indicated that TaAO3-6D was localized to chloroplasts. Prediction of cis-elements indicated that a large number of cis-elements involved in responses to ABA, SA, and antioxidants/electrophiles, as well as photoregulatory responses, were found in TaAO promoters, which suggests that the expression of TaAOs may be regulated by these factors. Finally, transcriptome and real-time PCR analysis showed that the expression of TaAOs belonging to Group III was strongly induced in wheat infected by F. graminearum during anthesis, while the expression of TaAOs belonging to Group I was heavily suppressed. Additionally, the inducible expression of TaAOs belonging to Group III during anthesis in wheat spikelets infected by F. graminearum was repressed by ABA. Finally, expression of almost all TaAOs was induced by exposure to cold treatment. These results indicate that TaAOs may participate in the response of wheat to F. graminearum infection and cold stress, and ABA may play a negative role in this process. This study lays a foundation for further investigation of TaAO genes and provides novel insights into their biological functions.</p

The Role of the Liquid–Liquid Interface in the Synthesis of Nonequilibrium Crystalline Wurtzite ZnS at Room Temperature

In this research, the role that the organic–inorganic liquid interface plays in the synthesis of nonequilibrium crystalline materials is investigated. A hierarchical nanocrystalline film of wurtzite ZnS, the high-temperature stable phase, is successfully prepared at room temperature by an interfacial in situ fabrication process. The organic–inorganic liquid interface constructed by n-hexane and water acts as the reaction zone for the synthesis of ZnS nanocrystalline film. A series of experimental results have proved that the liquid–liquid interface is the key factor for wurtzite ZnS formation at room temperature without any additive. The ZnS film consists of core–shell subunits characterized by ZnS nanoparticles around an organic core. Between the liquid–liquid interface, the core–shell subunits are coupled onto the surface of a SAM-modified substrate by terminal amino groups, so that the ZnS nanocrystalline film is formed by a layer-by-layer mode. This research brings forward a feasible route for synthesizing wurtzite ZnS in one-step process at room temperature and provides some beneficial information for studying the structural kinetics of nonequilibrium crystalline synthesis