Highly active and stable porous polymer heterogenous catalysts for decomposition of formic acid to produce H2

Formic acid (FA) has attracted extensive attention as a hydrogen storage material. Here, we develop two heterogeneous catalysts based on porous organic polymers (POPs). After loading the Ru species, the catalyst bearing the triphenylphosphine ligand showed excellent performance in terms of activity and stability for the decomposition of FA to produce hydrogen.     

A hierarchical cobalt/carbon nanotube hybrid nanocomplex-based ratiometric fluorescent nanosensor for ultrasensitive detection of hydrogen peroxide and glucose in human serum

Analytical and Bioanalytical Chemistry - Highly sensitive detection of H2O2 and glucose is critical for fundamental research and disease diagnosis. A ratiometric sensor can simultaneously afford...     

Protocells programmed through artificial reaction networks

As the smallest unit of life, cells attract interest due to their structural complexity and functional reliability. Protocells assembled by inanimate components are created as an artificial entity to mimic the structure and some essential properties of a natural cell, and artificial reaction networks are used to program the functions of protocells. Although the bottom-up construction of a protocell that can be considered truly ‘alive’ is still an ambitious goal, these man-made constructs with a certain degree of ‘liveness’ can offer effective tools to understand fundamental processes of cellular life, and have paved the new way for bionic applications. In this review, we highlight both the milestones and recent progress of protocells programmed by artificial reaction networks, including genetic circuits, enzyme-assisted non-genetic circuits, prebiotic mimicking reaction networks, and DNA dynamic circuits. Challenges and opportunities have also been discussed.

In this review, the milestones and recent progress of protocells programmed by various types of artificial reaction networks are highlighted.     

Bacteria‐Resistant Single Chain Cyclized/Knotted Polymer Coatings

Further to conventional linear, branched, crosslinked, and dendritic polymers, single chain cyclized/knotted polymers (SCKPs) have emerged as a new class of polymer structure with unique properties. Herein, the development of bacteria‐resistant SCKPs is reported and the effect of this structure on the resistance of polymer materials to bacteria is investigated. Four SCKPs were synthesized by reversible addition fragmentation chain transfer (RAFT) homopolymerization of multivinyl monomers (MVMs) and then crosslinked by UV light to form SCKP films. Regardless of MVM type used, the resulting SCKP films showed much higher resistance to bacteria, and up to 75 % less bacterial attachment and biofilm formation, in comparison with the corresponding non‐SCKP films. This is due to the altered surface morphology and hydrophobicity of the SCKP films. These results highlight the critical role of the SCKP structure in enhancing the resistance of polymeric materials to bacteria.     

Self-healing Supramolecular Polymer Composites by Hydrogen Bonding Interactions between Hyperbranched Polymer and Graphene Oxide

A self-healing supramolecular polymer composite (HSP-GO) was designed and prepared via incorporation of modified graphene oxide to hyperbranched polymer by hydrogen-bonding interactions.The polymer matrix based on amino-terminated hyperbranched polymer (HSP-NH2) was synthesized by carboxylation,Curtius rearrangement,and amination of hydroxyl-terminated hyperbranched polyester (HP-OH),while the modified graphene oxide was prepared by transformation of hydroxyl to isocyanate and further to carbamate ester.Spectroscopic methods were utilized to characterize the obtained polymer composites.Stress-strain test was selected to carefully study the self-healing property of HSP-GO.It is found that a small amount of modified graphene oxide (up to 2 wt％) improves the glass transition temperature (Tg),tensile strength,Young's modulus,and self-healing efficiency of the polymer composites.After healed at room temperature for 10 min,the addition of modified graphene oxide improves the self-healing efficiency to 3 7％ of its original tensile strength.The experiment result shows that the self-healing efficiency is related to the density of hydrogen bonding site and the molecular movement.     

Droplet impact on wetted structured surfaces

In this study, we numerically investigate the droplet impact onto a thin liquid film deposited on a structured surface with square pillars and cavities. The time evolution of crown geometry is strongly affected by the surface structure. When the thickness of the liquid film is larger than the structure height, the expanding speed of the crown base radius is independent of the structure width. However, if the liquid film thickness is equal to the structure height, the crown base expands slower as...     

UPLC-MS—MS法测定血液中5种吩噻嗪类药物

建立了超高效液相色谱串联质谱法测定血液中5种吩噻嗪类药物的方法。血液样品经过沉淀蛋白后,在HSSSBC18色谱柱上,经乙腈-0．1％甲酸水溶液梯度洗脱分离,用液相色谱-串联质谱仪以电喷雾电离（ESI＋）、多反应监泖l（MRM）方式进行分析。血液样本中异丙嗪、泰尔登、氯丙嗪、奋乃静、三氟拉嗪提取回收率分剐为62％-65％,71％-97％,66％-107％,72％-95％,77％-96％,检出限分别为0．02,0．01,0．01,0．01,0．01ng／mL。测定结果的相对标准偏差小于7％（n=6）。线性范围为0．05-20ng／mL,相关系数大于0．999。该方法适用于血液中吩噻嗪类药物的分析。     

Processing-Structure-Properties Relationships of Glycerol-Plasticized Silk Films

Silk possesses excellent mechanical properties and biocompatibility due to its unique protein sequences and hierarchical structures. Thus, it has been widely used as a biomaterial in a broad spectrum of biomedical applications. In this study, an in-depth investigation of glycerol-plasticized silk films was carried out to understand the processing-structure-properties relationships. A series of glycerol-plasticized silk films with glycerol contents in the range of 0 to 30% (w/w) were prepared. The molecular structures and organizations of silk proteins and the interactions between glycerol and proteins were studied using FTIR, XRD, and DSC. At a low glycerol content (<12%), DSC revealed that the glass transition temperature and thermally induced crystallization temperature decreased as the glycerol content increased, implying that glycerol mainly interacts with silk proteins through hydrogen bonding. As the glycerol content further increased, the chain mobility of the silk proteins was promoted, leading to the formation of β-sheet structures, water insolubility, and increased crystallinity. In addition, the stretchability and toughness of the films were significantly enhanced. The role of glycerol as a plasticizer in regulating the silk protein structures and determining the properties of the films was thoroughly discussed.     

Study on Purification and Characterization of Polyphenol Oxidase from Acetes chinensis

Acetes chinensis (belonging to the Decapoda Sergestidae genus) is widely distributed in East Asian waters and is extremely widespread and present in the shallow coastal areas of China. Polyphenol oxidase (PPO), which was extracted from Acetes chinensis, was purified in a four-step procedure involving phosphate-buffered saline treatment, ammonium sulphate precipitation, DEAE-Cellulose chromatography, and Phenyl-Sepharose HP chromatography, and then, its biochemical characterization was measured. The specific activity of the purified enzyme was increased to 643.4 U/mg, which is a 30.35 times increase in purification, and the recovery rate was 17.9%. L-dopa was used as the substrate, the enzymatic reactions catalyzed by PPO conformed to the Michaelis equation, the maximum reaction velocity was 769.23 U/mL, and the Michaelis constant K_m was 0.846 mmol/L. The optimal pH of PPO from Acetes chinensis was 7.5, and the optimal temperature was 35 °C. The metal ions experiment showed that Mn²⁺ and K⁺ could enhance the activity of PPO; that Ba²⁺ and Ca²⁺ could inhibit the activity of PPO; and that Cu²⁺ had a double effect on PPO, increasing the PPO activity at low concentrations and inhibiting the PPO activity at high concentrations. The inhibitor experiment showed that the inhibitory effects of EDTA and kojic acid were weak and that ascorbic acid and sodium pyrophosphate had good inhibitory effects. The purification and characterization of Acetes chinensis serve as guidelines for the prediction of enzyme behavior, leading to effective prevention of enzymatic browning during processing.