Preparation of Titania-Silica Composite Aerogel at Atmospheric Pressure and Its Catalytic Performance in the Synthesis of Poly (Butylene Succinate).

Titanates are widely used in the synthesis of polyesters, such as Poly (butylene succinate) (PBS), due to their excellent catalytic activity for polycondensation. However, the hydrolysis sensitivity of titanate and side reactions at high temperatures restrict the further improvement of the molecular weight of polyesters and lead to the high content of end carboxyl group content in the products. In this work, we prepared titania-silica composite aerogels with resistance to hydrolysis and large specific surface area, which were further explored as an efficient catalyst for polycondensation reactions. A series of titania-silica composite aerogel catalysts for PBS polycondensation were successfully prepared by the sol-gel method. The influence of a Ti/Si ratio on the surface morphology and structure of the aerogels was examined. Titania-silica composite aerogel exhibits the surface characteristics of high specific surface area and high Lewis acid content. The specific surface area of titania-silica composite aerogels can reach 524.59 m2/g, and the Lewis acid content on the surface can reach 370.29 µmol/g. Furthermore, the catalytic performance for the polycondensation reaction of PBS was investigated. The intrinsic viscosity of PBS synthesized by catalysis with the composite catalyst with a Ti/Si ratio of 9/1 reaches 1.74 dL/g, with the Mn of 7.72 × 104 g/mol. The hydrolysis resistance stability of the titania-silica composite aerogel is greatly improved compared with traditional tetrabutyl titanate (TBT), and the end carboxyl group content of PBS is effectively reduced to lower than 30 mol/ton.

Transition-Metal-Free Site-Selective γ-C(sp2)-H Monoiodination of Arenes Directed by an Aliphatic Keto Group.

A general γ-C(sp2)-H iodination method directed by an aliphatic keto group has been developed under transition-metal-free conditions for the first time, generating iodoarenes in good to excellent yields with excellent site selectivity. This protocol features a wide range of aryl-substituted ketones, short reaction times, mild reaction conditions, and scalable synthetic procedures. A possible reaction mechanism was also proposed based on several control experiments.

Ingenious preparation of N/NiOx co-doped hierarchical porous carbon nanosheets derived from chitosan nanofibers for high-performance supercapacitors.

It is still a key challenge to find suitable materials and methods to obtain super capacitors (SCs) with high specific capacitance due to the difficulty of balancing low theoretical capacity of conventional carbon materials and the poor ion transportability of transition metal oxide. In this work, N Ni dual-doped porous carbon nanosheets (NiOx-NCNSs) are prepared through a novel way using original N-doped chitosan nanofibers and nickel nitrate to form honeycomb layered structure constructed by 2D fiber network as precursors. NiOx-NCNS exhibits a high specific surface area of 1847.4 m2 g-1 with a rich N content of up to 5.16 wt% and shows a higher specific capacitance of 614.6 F g-1 at a current density of 1 A g-1 than that of carbon nanosheets of undoped Ni (NCNS) (427.5 F g-1). More specifically, the SC assembled using NiOx-NCNS electrodes achieves a high energy density of 20.3 W h kg-1 at a power density of 240.9 W kg-1, which is superior to most of the CNS-based SCs that have been reported. After 10 000 cycles, the symmetric SC retains approximately 85.61% of the initial capacitance. The strategy provided in this work probes the feasibility of high-performance SCs.

Nanocomposites membranes from cellulose nanofibers, SiO2 and carboxymethyl cellulose with improved properties.

The binary nanocomposites blended by carboxymethyl cellulose (CMC) and SiO2 nanoparticles were constructed to prepare the films with superior thermal stability and flame retardant properties. The incorporation of cellulose nanofibers(CNFs) and SiO2 nanoparticles were followed to prepare ternary nanocomposite films exhibiting excellent mechanical properties. The mechanism and chemical reaction of the thermal decomposition for the CMC/SiO2 composite membrane were proposed, which showed that the mass residuals were Na2CO3, SiO2 and Na2SiO3, Na2CO3 when the content of the SiO2 nanoparticles was lowered and higher than 9.6 %, respectively. Compared with the pure CMC, micro combustion calorimeter (MCC) showed that the total heat release (THR) and the peak heat release rate (PHRR) both decreased from 6.4 kJ/g to 5.8 kJ/g, 134 w/g to 27 w/g, respectively. Moreover, mechanical properties of CMC/CNFs/SiO2 membrane showed that the toughness and rigidity of the nanocomposites increased by 56.0 % and 63.0 % on the basis of CMC, respectively.

Synthesis and biological evaluation of 1-(benzofuran-3-yl)-4-(3,4,5-trimethoxyphenyl)-1H-1,2,3-triazole derivatives as tubulin polymerization inhibitors.

The key functions of microtubules and the mitotic spindle in cell division make them attractive targets for cancer therapy. In this study, a series of 1-(benzofuran-3-yl)-4-(3,4,5-trimethoxyphenyl)-1H-1,2,3-triazole derivatives was synthesized, and their antiproliferative activities against HCT116, HeLa, HepG2, and A549 cells were evaluated. 6-Methoxy-N-phenyl-3-(4-(3,4,5-trimethoxyphenyl)-1H-1,2,3-triazol-1-yl)benzofuran-2-carboxamide (17g) exhibited the strongest antiproliferative activities, with IC50 values ranging from 0.57 to 5.7 µM. Mechanistic studies showed that 17g inhibited tubulin polymerization, leading to the disruption of mitotic spindle formation, cell cycle arrest in the G2/M phase, and apoptosis of A549 cells. A docking study indicated that 17g was a good molecular fit at the colchicine binding site of tubulin. These results showed that 17g is a potential anticancer compound that is worthy of further development as a tubulin polymerization inhibitor.

p-Toluenesulfonic acid catalysed fluorination of α-branched ketones for the construction of fluorinated quaternary carbon centres.

A p-toluenesulfonic acid catalyzed fluorination of α-branched ketones for the construction of fluorinated quaternary carbon centers has been developed, featuring a broad substrate scope, environmentally benign reaction conditions, and operational simplicity.

CQDs-Doped Magnetic Electrospun Nanofibers: Fluorescence Self-Display and Adsorption Removal of Mercury(II).

This paper reports the carbon quantum dots-doped magnetic electrospinning nanofibers for the self-display and removal of Hg(II) ions from water. The fluorescent carbon quantum dots and magnetic Fe3O4 nanoparticles were pre-prepared successfully, and they appeared to be homogeneously dispersed in nanofibers via electrospinning. During the sorption of Hg(II) ions, the significant fluorescence signals of nanofibers gradually declined and exhibited a good linear relationship with cumulative adsorption capacity, which could be easily recorded by the photoluminescence spectra. The sorption performance of mercury ions onto the nanofibers was investigated in terms of different experimental factors including contact time, solution pH value, and initial ion concentration. Considering the actual parameters, the nanofibers were sensitive self-display adsorption system for Hg(II) ions in the existence of other cation. The sorption data were described by different kinetic models, which indicate that the whole sorption was controlled by chemical adsorption. The intraparticle diffusion mass transfer was not obvious in this system, which further proved the uniform adsorption and even fluorescence quenching in nanofibers. Additionally, the nanocomposite fiber could regenerate in several cycles with no significant loss of adsorption capacity and fluorescence intensity. Thus, the nanofibers are promising alternatives for environmental pollution incidents. It is especially competent due to its high efficiency for self-display and removal of high concentration of mercury ions.

Atropine 0.5% eyedrops for the treatment of children with low myopia: A randomized controlled trial.

BACKGROUND: This study aimed to assess the efficacy and safety of atropine 0.5% eyedrops (ATE) for the treatment of children with low myopia (LM). METHODS: In this study, a total of 126 children with LM were randomly divided into an intervention group (administered 0.5% ATE) and a control group (administered a placebo), with 63 children in each group. The outcome measurements were changes in the spherical equivalent (SE), and axial length (AL), as well as adverse events (AEs). RESULTS: Compared with placebo, administration of 0.5% ATE led to less progression in LM, as measured by SE, and less increase in AL (P < .01). In addition, no serious AEs occurred in both the groups. CONCLUSION: About 0.5% ATE was efficacious and safe for controlling myopia in children with LM.