Glycosidic Constituents of Celastrus orbiculatus

Three new, 1 – 3 , and seven known phenolic and terpenic glycosides were isolated from the BuOH‐soluble fraction of 95% EtOH extract of the roots and rhizomes of Celastrus orbiculatus. The structures of the new compounds were elucidated as carvacrol 2‐O‐α‐L ‐rhamnopyranosyl‐(1→6)‐β‐D ‐glucopyranoside ( 1 ), 5‐methoxycarvacrol 2‐O‐α‐L ‐rhamnopyranosyl‐(1→6)‐β‐D ‐glucopyranoside ( 2 ), and 15‐hydroxytorreyol 10‐O‐β‐D ‐apiofuranosyl‐(1→6)‐β‐D ‐glucopyranoside ( 3 ) on the basis of spectroscopic analysis and chemical methods.     

分段控温原位聚合沉积法制备苯胺-邻苯二胺共聚物薄膜

提出在玻璃基体表面原位聚合沉积制备苯胺-邻苯二胺(An-oPD)共聚物薄膜的一种方法:分段控温法,即高温预聚(高水浴温度)、低温聚合(冰水浴)。该法可在缩短聚合反应时间的同时避免暴聚现象,提高成膜效率,所得共聚物薄膜形貌特征优异、膜厚均匀;该法可制得饱和厚度120 nm,电导率9.16×10-2S/cm的An-oPD共聚物薄膜,具有与均聚PAn薄膜不同的电致变色性能。     

苯胺分散聚合中稳定剂PVP-K90的稳定机理

通过分散聚合,在聚酰亚胺(PI)薄膜表面原位沉积聚苯胺(PANI)制备聚苯胺-聚酰亚胺-聚苯胺(PANI-PI-PANI)复合膜。考察了苯胺分散聚合中,不同空间稳定剂的稳定效果(不同分子量的大分子稳定剂PVP及小分子稳定剂CTAB、Tween-20),初步探讨了大分子稳定剂PVP-K90的稳定机理。实验表明,高分子量PVP-K90可稳定PANI良好成膜,且紫外和红外光谱分析证实PANI膜为掺杂态PANI,膜中不含有稳定剂PVP-K90。低分子量的PVP-K30和两亲性小分子稳定剂不能良好地稳定PANI成膜,稳定作用较差。PVP-K90的稳定作用不仅依据亲水-疏水相互作用和表面能的减少,还可能与高分子量PVP的长链分子结构及与水和苯胺的特殊相互作用有关,可用齐聚物沉淀成核机理解释。     

Synthesis,Structure, and Magnetic Properties of Three Novel Sandwich‐type Tungstobismuthates with Triethanolamine

Three novel sandwich‐type polyoxotungstates ( 1 – 3 ) were synthesized in good yield using an in‐situ conventional solution synthesis method by reaction in aqueous media below 80 °C. Compounds 1 – 3 represent the first structurally characterized β‐B‐BiW₉ sandwich‐type polyoxometalates with triethanolamine cations. All three compounds have the same building unit [(X(H₂O)₃)₂(X_0.5W_0.5O)₂(β‐B‐BiW₉O₃₃)₂)]^10– [X = Mn^II ( 1 ), Co^II ( 2 ), Ni^II ( 3 )]. The adjacent units of 1 or 2 are joined by Na⁺ cations in different ways to construct 1D chains or 2D sheets. A 3D supramolecular structure is further formed by hydrogen bond interactions among water molecules and protonated triethanolamine cations. Meanwhile only compound 3 shows a 0D structure. The compounds were characterized by elemental analysis, IR spectroscopy, TG analysis, and single‐crystal X‐ray diffraction. Magnetic measurements on a sample of 1 show the presence of paramagnetic interactions.     

Biocompatible copper(I) catalysts for in vivo imaging of glycans

The Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) is the standard method for bioorthogonal conjugation. However, current Cu(I) catalyst formulations are toxic, hindering their use in living systems. Here we report that BTTES, a tris(triazolylmethyl)amine-based ligand for Cu(I), promotes the cycloaddition reaction rapidly in living systems without apparent toxicity. This catalyst allows, for the first time, noninvasive imaging of fucosylated glycans during zebrafish early embryogenesis. We microinjected embryos with alkyne-bearing GDP-fucose at the one-cell stage and detected the metabolically incorporated unnatural sugars using the biocompatible click chemistry. Labeled glycans could be imaged in the enveloping layer of zebrafish embryos between blastula and early larval stages. This new method paves the way for rapid, noninvasive imaging of biomolecules in living organisms.     

Quantum dots sensitized graphene: In situ growth and application in photoelectrochemical cells

A novel photoelectrochemical cells (PEC) based on quantum dots (QDs) sensitized graphene for light harvesting and energy conversion was described in this work. QDs sensitized graphene was prepared by in situ growth of QDs on noncovalently functionalized graphene. QDs sensitized graphene photoelectrodes showed enhanced photocurrent generation capability and incident photon-to-electron conversion efficiency (IPCE) at visible light, and could also be an efficient platform for other optoelectronic applications.     

MimoDB: a new repository for mimotope data derived from phage display technology

Peptides selected from phage-displayed random peptide libraries are valuable in two aspects. On one hand, these peptides are candidates for new diagnostics, therapeutics and vaccines. On the other hand, they can be used to predict the networks or sites of protein-protein interactions. MimoDB, a new repository for these peptides, was developed, in which 10,716 peptides collected from 571 publications were grouped into 1,229 sets. Besides peptide sequences, other important information, such as the target, template, library and complex structure, was also included. MimoDB can be browsed and searched through a user-friendly web interface. For computational biologists, MimoDB can be used to derive customized data sets and benchmarks, which are useful for new algorithm development and tool evaluation. For experimental biologists, their results can be searched against the MimoDB database to exclude possible target-unrelated peptides. The MimoDB database is freely accessible at http://immunet.cn/mimodb/.     

Water-in-oil microemulsion method preparation and capacitance performance study of Li4Mn5O12

Spinel Li₄Mn₅O₁₂ nanoparticles are successfully prepared by water-in-oil microemulsion method and characterized by X-ray diffraction and scanning electron microscopy. The Li₄Mn₅O₁₂ nanoparticles have sphere-like morphology with particle size less than 50 nm. The Li₄Mn₅O₁₂ and activated carbon (AC) were used as electrodes of Li₄Mn₅O₁₂/AC supercapacitor, respectively. The electrochemical capacitance performance of the supercapacitor was investigated by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. The results showed that the single electrode was able to deliver specific capacitance 252 F g^?1 within potential range 0–1.4 V at a scan rate of 5 mV s^?1 in 1 mol L^?1 Li₂SO₄ solution, and it also showed high coulombic efficiency close to 100%. This material exhibited a good cycling performance.