Imine-linked microporous polymer organic frameworks (POFs) were synthesized via Schiff base condensation between 1,3,5-triformylbenzene and several readily available diamine monomers. Our facile, one-pot approach results in quantitative yields of POFs with the flexibility to incorporate several functional groups in their pores for tuning the interaction of their surface with different guest molecules. Synthesized POFs exhibit high specific surface areas (up to 1500 m2 g−1) as well as high isosteric heats of H2 adsorption (up to 8.2 kJ mol−1).

We have applied two strategies for the cloning of four genes responsible for the biosynthesis of the GT1a ganglioside mimic in the lipooligosaccharide (LOS) of a bacterial pathogen, Campylobacter jejuni OH4384, which has been associated with Guillain-Barré syndrome. We first cloned a gene encoding an ␣-2,3-sialyltransferase (cst-I) using an activity screening strategy. We then used nucleotide sequence information from the recently completed sequence from C. jejuni NCTC 11168 to amplify a region involved in LOS biosynthesis from C. jejuni OH4384. The LOS biosynthesis locus from C. jejuni OH4384 is 11.47 kilobase pairs and encodes 13 partial or complete open reading frames, while the corresponding locus in C. jejuni NCTC 11168 spans 13.49 kilobase pairs and contains 15 open reading frames, indicating a different organization between these two strains. Potential glycosyltransferase genes were cloned individually, expressed in Escherichia coli, and assayed using synthetic fluorescent oligosaccharides as acceptors. We identified genes encoding a ␤-1,4-N-acetylgalactosaminyl-transferase (cgtA), a ␤-1,3-galactosyltransferase (cgtB), and a bifunctional sialyltransferase (cst-II), which transfers sialic acid to O-3 of galactose and to O-8 of a sialic acid that is linked ␣-2,3-to a galactose. The linkage specificity of each identified glycosyltransferase was confirmed by NMR analysis at 600 MHz on nanomole amounts of model compounds synthesized in vitro. Using a gradient inverse broadband nano-NMR probe, sequence information could be obtained by detection of 3 J(C,H) correlations across the glycosidic bond. The role of cgtA and cst-II in the synthesis of the GT1a mimic in C. jejuni OH4384 were confirmed by comparing their sequence and activity with corresponding homologues in two related C. jejuni strains that express shorter ganglioside mimics in their LOS.

Covalent organic frameworks (COFs) are crystalline polymers with permanent porosity. They are usually synthesized as micrometer-sized powders or two-dimensional thin films and membranes for applications in molecular storage, separation, and catalysis. In this work, we report a general method to integrate COFs with imine or β-ketoenamine linkages into three-dimensional (3D)-printing materials. A 3D-printing template, Pluronic F127, was introduced to coassemble with imine polymers in an aqueous environment. By limitation of the degree of imine polycondensation during COF formation, the amorphous imine polymer and F127 form coassembled 3D-printable hydrogels with suitable shear thinning and rapid self-healing properties. After the removal of F127 followed by an amorphous-to-crystalline transformation, three β-ketoenamine- and imine-based COFs were fabricated into 3D monoliths possessing high crystallinity, hierarchical pores with high surface areas, good structural integrity, and robust mechanical stability. Moreover, when multiple COF precursor inks were employed for 3D printing, heterogeneous dual-component COF monoliths were fabricated with high spatial precision. This method not only enables the development of COFs with sophisticated 3D macrostructure but also facilitates the heterogeneous integration of COFs into devices with interconnected interfaces at the molecular level.

The addition of numerous main metal elements into highentropy alloys (HEAs) have been popular since their discovery in 2004. [2] This has provided a vast combinatorial space for the exploration of new materials with unexplored abnormal functionalities. In general, four core factors, namely, sluggish diffusion, configurational entropy, lattice distortion, and cocktail effects, affect the crystal structure and properties of HEAs. [3] Since 2015, the concept of high entropy has been successfully expanded to include oxides. [4] Similar to HEAs, high-entropy oxides (HEOs) are defined as compositions consisting of oxygen and more than five metal cations in equimolar or near equimolar ratios in the range of 5-35% atomic concentration. [5] HEOs are rapidly emerging as delicate functional constituents that offer excellent compositional flexibility that permits the stabilization of numerous compositions with various crystal structures (e.g., rock-salt, spinel, fluorite, perovskite, and pyrochlore phases). [6] Consequently, HEOs present numerous attractive functional properties, such as high ionic conductivity; [7] superior storage capacity retention and good stable cycles of Li battery; [8] low thermal conductivity and good thermal stability; colossal dielectric constant; [9] and novel magnetic phenomena. [10] However, a deep understanding of their microstructures has yet to emerge. Thus, it is extremely urgent to learn more about the microstructure of HEOs to further understand their anomalous High-entropy oxides (HEOs), which incorporate multiple-principal cations into single-phase crystals and interact with diverse metal ions, extend the border for available compositions and unprecedented properties. Herein, a high-entropy-stabilized (Ca 0.2 Sr 0.2 Ba 0.2 La 0.2 Pb 0.2 )TiO 3 perovskite is reported, and the effective absorption bandwidth (90% absorption) improves almost two times than that of BaTiO 3 . The results demonstrate that the regulation of entropy configuration can yield significant grain boundaries, oxygen defects, and an ultradense distorted lattice. These characteristics give rise to strong interfacial and defect-induced polarizations, thus synergistically contributing to the dielectric attenuation performance. Moreover, the large strains derived from the strong lattice distortions in the high-entropy perovskite offer varied transport for electron carriers. The high-entropy-enhanced positive/negative charges accumulation around grain boundaries and strain-concentrated location, quantitatively validated by electron holography, results in unusual dielectric polarization loss. This study opens up an effective avenue for designing strong microwave absorption materials to satisfy the increasingly demanding requirements of advanced and integrated electronics. This work also offers a paradigm for improving other interesting properties for HEOs through entropy engineering.

Exudates from six species of the genus Eucalyptus and one of the genus Corymbia (formerly Eucalyptus), from the family Myrtaceae, have been characterized by solid-state 13C and solution 1H NMR spectroscopy for the first time. Although these eucalypt kinos, as these exudates often are called, resemble resin (terpenoid) and gum (carbohydrate) exudates in physical appearance, their NMR spectra are dramatically different. In addition to lacking the characteristic terpene saturated resonances, they exhibit strong unsaturated resonances, which are weak for resins and absent for gums. We additionally report that exudates from genera of several other families of flowering plants (Amyris, Centrolobium, Guaiacum, Liquidambar, and Prosopis) also exhibit part or all of this kino spectroscopic signature.